CA1250976A - Method for generating electronically controllable color elements and color display based on the method - Google Patents
Method for generating electronically controllable color elements and color display based on the methodInfo
- Publication number
- CA1250976A CA1250976A CA000503253A CA503253A CA1250976A CA 1250976 A CA1250976 A CA 1250976A CA 000503253 A CA000503253 A CA 000503253A CA 503253 A CA503253 A CA 503253A CA 1250976 A CA1250976 A CA 1250976A
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- CA
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- Prior art keywords
- light
- color
- gate
- source system
- light source
- Prior art date
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Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133621—Illuminating devices providing coloured light
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/23—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour for the control of the colour
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3648—Control of matrices with row and column drivers using an active matrix
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/12—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by switched stationary formation of lamps, photocells or light relays
- H04N3/127—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by switched stationary formation of lamps, photocells or light relays using liquid crystals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3102—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators
- H04N9/3111—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying the colours sequentially, e.g. by using sequentially activated light sources
- H04N9/3114—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying the colours sequentially, e.g. by using sequentially activated light sources by using a sequential colour filter producing one colour at a time
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133621—Illuminating devices providing coloured light
- G02F1/133622—Colour sequential illumination
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2300/00—Aspects of the constitution of display devices
- G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
- G09G2300/0809—Several active elements per pixel in active matrix panels
- G09G2300/0814—Several active elements per pixel in active matrix panels used for selection purposes, e.g. logical AND for partial update
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2300/00—Aspects of the constitution of display devices
- G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
- G09G2300/0809—Several active elements per pixel in active matrix panels
- G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0235—Field-sequential colour display
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/024—Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/08—Details of timing specific for flat panels, other than clock recovery
Abstract
ABSTRACT OF THE DISCLOSURE
Described herein are a method for generating electronically controllable color elements and a color display based on the method, comprising a light gate matrix (9), and a light source system with a set of primary color sources (6, 7, 8) for the primary colors (R, G, B), and control circuits (1...4) for controlling the transmission of light gates in the light gate matrix (9) for a level corresponding to the intensity of the respective primary color in the composite color spectrum of the displayed picture element.
In accordance with the invention, the primary color is generated by pulsing the primary color sources and using only one light gate per picture element for controlling the primary color intensities at the picture element.
The present invention facilitates, among other things, perfect color convergence, improved light transmission efficiency, and simpler production technology for transmission type color displays, due to single light gate construction of the controlled light gate matrix (Figures 1a and 1b).
Described herein are a method for generating electronically controllable color elements and a color display based on the method, comprising a light gate matrix (9), and a light source system with a set of primary color sources (6, 7, 8) for the primary colors (R, G, B), and control circuits (1...4) for controlling the transmission of light gates in the light gate matrix (9) for a level corresponding to the intensity of the respective primary color in the composite color spectrum of the displayed picture element.
In accordance with the invention, the primary color is generated by pulsing the primary color sources and using only one light gate per picture element for controlling the primary color intensities at the picture element.
The present invention facilitates, among other things, perfect color convergence, improved light transmission efficiency, and simpler production technology for transmission type color displays, due to single light gate construction of the controlled light gate matrix (Figures 1a and 1b).
Description
Method for generating electronically controllable color element~ and color display based on the methodO
The present invention provides a method in accordance with the preamble o claim 1 for generating electronically controllable color elements on the screen of a color dicplay.
The invention also covers a color display, implemented with this technology.
The prior-art methods are covered in the following publica-tions:
(1) R. Vatne, P.A. Johnson, Jr., P.J. Bos:
A LC/CRT Field-Sequential Color Display, SID 83 DIGEST, pp. 28...29.
The present invention provides a method in accordance with the preamble o claim 1 for generating electronically controllable color elements on the screen of a color dicplay.
The invention also covers a color display, implemented with this technology.
The prior-art methods are covered in the following publica-tions:
(1) R. Vatne, P.A. Johnson, Jr., P.J. Bos:
A LC/CRT Field-Sequential Color Display, SID 83 DIGEST, pp. 28...29.
(2) P J Bos P.A. Johnson, Jr., K.R. Koehler/Beran:
A Liquid Crystal Optical-Switching Device, SID 8~ DIGEST, pp. 30...31.
A Liquid Crystal Optical-Switching Device, SID 8~ DIGEST, pp. 30...31.
(3) G. Haertling:
PLZT Color Displays, SID 84 DIGEST, pp. 137...140.
PLZT Color Displays, SID 84 DIGEST, pp. 137...140.
(4) H. Kamamori, M. Suginoya, Y. Terada, K. Iwasa:
Multicolor Graphic LCD with Tricolor Layer~ Formed by Electrodeposition, SID 84 DIGEST, pp. 215...218.
Multicolor Graphic LCD with Tricolor Layer~ Formed by Electrodeposition, SID 84 DIGEST, pp. 215...218.
(5) W.A. Barrow, R.B. Coovert, C.N. King:
Strontium Sulphide: The Host for a New High-Efficiency Thin Film EL Blue Phosphor, SID 84 DIGEST, pp. 249.~.250.
Strontium Sulphide: The Host for a New High-Efficiency Thin Film EL Blue Phosphor, SID 84 DIGEST, pp. 249.~.250.
(6) Electroluminescent Displays~
Report 6475, p. 83.
~æsæ~
~7) W.F. Goede:
Technologies for High-Resolution Color Display, 1982 International Display Research Conference, 1482 IEEE, pp. 60.. 63.
(8) T. Uchida, S. Yamamoto, Y. Shivata:
A Full-Color Matrix LCD with Color Layers on the Elec rodes, 1982 International Display Research Conference, 1982 IEEE, pp. 166...170.
.
(9) Displays, October 1984, p. 212.
(10) S. Morozumi, K. Oguchi, S. Yazawa, T. Kodaira, H. Ohshima, T. Mano:
B/W and Color LC Video Displays Addressed by Poly Si TFTS
SID 83 DIGEST, pp. 156...157.
(11) M. Yoshida, K. Tanaka, K. Taniguchi, T. Yamashita, Y. Kakihara, T. Inoguchi:
AC Thin-Film EL Device That Emits White Light, SID 80 DIGEST, pp. 106...107.
(12) J. Chevalier, J-P. Valves:
CRTs With Phosphor and Impregnated Cathodes for Avionics Di~plays, SID 82 DIGEST, pp. 60...61.
(13) Large Screen Display Performance Comparison Chart SID 82 DIGEST, p. 107.
(14) M.G. Clark, I.A. Shanks:
A Field-Sequential Color CRT Using a Liquid Crystal Color Switch SID 82 DIGEST, pp. 172...173.
5~
(15) J.A. Roese, L.E. McCleary, A.S. Khalafalla:
3-D Computex Graphics Using PLZT Electrooptic Ceramics, SID 78 DIGEST, p. 16.
(16) SID 78 DIGEST, p. 16.
(17) GB Patent Publication 2,061,587 (M. Stolov).
~18) B.E. Rogowitz:
Flicker Matchiny: A Technique for Measuring the Perceived Flicker of a VDT, SID 83 DIGEST, pp. 172...173.
(19) Mukao et al. (Hitachi Co. Ltd.):
~ikkei Microdevices, Special Issue, Spring '85 (20) R. Blinc, N.A. Clark, J. Goodby, S.A. Pikin, K. Yoshino:
Ferroelectrics, Vol. 58, Nos 1/2/3/4 (1934) + Vol. 59, Nos. 1/2 (1984).
~ FI Patent Publication 50,333 (J. Antson et al.).
The most generally applied solution for an electronic color display is the shadow-mask tube, common in color television sets, which is based on adjacently located triads of color elements, typically excited with three electron beams (7). In such a display, the entire screen comprises a large number of these color picture element~, or color pixels. A homogeneous color perception from this kind of a color display requires sufficient viewing distance between the observer and the screen to allow the color elements of the color triad to merge in the vision of the observer into a non-discretely perceived color pixel.
Color displays based on adjacent color elements, excited by ~eans other than the electro~ beam excitation, also exist. For example, the matrix-controlled ~luorescent plasma display is in principle capable cf generating a display equivalent to that of the shadow mask picture tube (16). These display devices are cate~orized as active display components, characterized with active emission o light from the color elements.
A color display with parallel control of adjacent color elements can also be formed from a light gate matrix with controllable light transmission, complemented with color ilters on the light path and a light source at the rear of the display (4, 8, 10). Such a light gate matrix is generally implemented with liquid-crystal (LC) cells in which each pixel typically comprises three light cells with individual parallel control, each cell being tuned to transmit one of the primary colors via its blue, green, or red filter. Correspondingly, the light source spectrum must contain sufficient energy at all primary color wave-lengths. The LC light gate matrix color display with color filters has been applied to small~size TV receivers with the advantages of low weight and low profile, compared to the conventional picture tube. One of the disadvantages of color displays with adjacent primary color light switches is the relatively low transmission efficiency, among other factors, caused by the fact that the light source emission for each primary color is efectively transmitted only via one third (1/3) of the pixel area. In practice, the effective light gate area is even smaller, due to the unavoidable lands between the light gates.
All display solutions with adjacent color elements are limited by insufficient color convergence, directly related to the relative distance between the primary color elements.
This disadvantage is especially discernible in color graphic displays and other color displays where there is a need for high definition.
~d. ~
One solution for improved color convergence is the so-called penetration picture tube, in which the light-emitting layer on the screen of the picture tube consists of superim-posed phosphor layers with different emission wavelengths for the primary colors (12). The emitted wavelength can be selected by altering the energy of the excited electron beam and therewith controlling the penetration depth to reach the phosphor layer with the desired wavelength.
However, the penetra~ion-type picture tubes do not cover the entire perceivable color spectrum. Due to the complicated control electronics of the electron beam acceleration voltage, the control functions in this kind of a picture tube are awkward. Consequently, the penetration picture tube is only used in special applications.
Another recently developed solution is a combination color display with sequential color fields of two pri~ary colors.
In this case, the picture fields for the two primary colors are generated with a single color picture tube complement-ed with color polarizers for color separation and LC color separators for the selection of se~uential color fields (1, 14). However, the scale of hues in this display i5 limited to the scale of the two primary colors and their combinations. In this system, generating a color picture without flicker presupposes that the LC color separator, in this case the polarization separator, is capable of operating at a frequency of about 100...120 Hz. The-turn-on and turn-off times of the LC cell, described in reference ~1), are about 1 ms. This is sufficient for fulfilling this requirement. The basic limitation~ of this solution are the restricted spectrum of colors within the combinations of the two primary color components and the high intensity loss which is due to the low transmission efficiency in the polarizer.
In a color picture projection display, the color picture is generally the addition of the separately generated ~3b. ;~' ~5 ~ ~ 7 ~i3 primary color pictures from the primary color channels.
These are combined in an optical lens system tha~ projects the primary color pictures on a single screen (13).
The color display method according to the invention aims to eliminate the disadvantages found in the conventional solutions mentioned above and to propose a completely new method and solution for providing color control in the color elements of a display, comprising a light source system and picture elements formed by light gates.
In accordance with the present invention, the 'Synchrogate' method implements the color control of picture elements in a color display with light gates, synchronized to sequential primary color pulses, which are individually generated in the incorporated light source system. Consequently, the light gates act as transmission-controlled switches for the rear-projecting light source in the systemO The transmission of a light gate is driven to proper level for the activation time of the primary color component to correspond to the intensity of the primary color component in the added color spectrum of the picture element. The primary c~lors are generated in the light source system as individual short pulses of colored light, sequentially pulsed at a rate which is sufficiently high for the continuous, flicXer-free perception of the added color from the picture element. The 'Synchrogate' method facilitates the generation of added colors by one light gate for each pixel, providing perfect color convergence.
The Synchrogate color display in accordance with the present invention comprises in its "direct view" mode a display screen with a matrix of light-gate-type picture elements or a group of light gates, a light source system at the rear of the display for generating the primary color light pulses, and a synchronization circuit for controlling these basic elements synchronously by control circuits.
Report 6475, p. 83.
~æsæ~
~7) W.F. Goede:
Technologies for High-Resolution Color Display, 1982 International Display Research Conference, 1482 IEEE, pp. 60.. 63.
(8) T. Uchida, S. Yamamoto, Y. Shivata:
A Full-Color Matrix LCD with Color Layers on the Elec rodes, 1982 International Display Research Conference, 1982 IEEE, pp. 166...170.
.
(9) Displays, October 1984, p. 212.
(10) S. Morozumi, K. Oguchi, S. Yazawa, T. Kodaira, H. Ohshima, T. Mano:
B/W and Color LC Video Displays Addressed by Poly Si TFTS
SID 83 DIGEST, pp. 156...157.
(11) M. Yoshida, K. Tanaka, K. Taniguchi, T. Yamashita, Y. Kakihara, T. Inoguchi:
AC Thin-Film EL Device That Emits White Light, SID 80 DIGEST, pp. 106...107.
(12) J. Chevalier, J-P. Valves:
CRTs With Phosphor and Impregnated Cathodes for Avionics Di~plays, SID 82 DIGEST, pp. 60...61.
(13) Large Screen Display Performance Comparison Chart SID 82 DIGEST, p. 107.
(14) M.G. Clark, I.A. Shanks:
A Field-Sequential Color CRT Using a Liquid Crystal Color Switch SID 82 DIGEST, pp. 172...173.
5~
(15) J.A. Roese, L.E. McCleary, A.S. Khalafalla:
3-D Computex Graphics Using PLZT Electrooptic Ceramics, SID 78 DIGEST, p. 16.
(16) SID 78 DIGEST, p. 16.
(17) GB Patent Publication 2,061,587 (M. Stolov).
~18) B.E. Rogowitz:
Flicker Matchiny: A Technique for Measuring the Perceived Flicker of a VDT, SID 83 DIGEST, pp. 172...173.
(19) Mukao et al. (Hitachi Co. Ltd.):
~ikkei Microdevices, Special Issue, Spring '85 (20) R. Blinc, N.A. Clark, J. Goodby, S.A. Pikin, K. Yoshino:
Ferroelectrics, Vol. 58, Nos 1/2/3/4 (1934) + Vol. 59, Nos. 1/2 (1984).
~ FI Patent Publication 50,333 (J. Antson et al.).
The most generally applied solution for an electronic color display is the shadow-mask tube, common in color television sets, which is based on adjacently located triads of color elements, typically excited with three electron beams (7). In such a display, the entire screen comprises a large number of these color picture element~, or color pixels. A homogeneous color perception from this kind of a color display requires sufficient viewing distance between the observer and the screen to allow the color elements of the color triad to merge in the vision of the observer into a non-discretely perceived color pixel.
Color displays based on adjacent color elements, excited by ~eans other than the electro~ beam excitation, also exist. For example, the matrix-controlled ~luorescent plasma display is in principle capable cf generating a display equivalent to that of the shadow mask picture tube (16). These display devices are cate~orized as active display components, characterized with active emission o light from the color elements.
A color display with parallel control of adjacent color elements can also be formed from a light gate matrix with controllable light transmission, complemented with color ilters on the light path and a light source at the rear of the display (4, 8, 10). Such a light gate matrix is generally implemented with liquid-crystal (LC) cells in which each pixel typically comprises three light cells with individual parallel control, each cell being tuned to transmit one of the primary colors via its blue, green, or red filter. Correspondingly, the light source spectrum must contain sufficient energy at all primary color wave-lengths. The LC light gate matrix color display with color filters has been applied to small~size TV receivers with the advantages of low weight and low profile, compared to the conventional picture tube. One of the disadvantages of color displays with adjacent primary color light switches is the relatively low transmission efficiency, among other factors, caused by the fact that the light source emission for each primary color is efectively transmitted only via one third (1/3) of the pixel area. In practice, the effective light gate area is even smaller, due to the unavoidable lands between the light gates.
All display solutions with adjacent color elements are limited by insufficient color convergence, directly related to the relative distance between the primary color elements.
This disadvantage is especially discernible in color graphic displays and other color displays where there is a need for high definition.
~d. ~
One solution for improved color convergence is the so-called penetration picture tube, in which the light-emitting layer on the screen of the picture tube consists of superim-posed phosphor layers with different emission wavelengths for the primary colors (12). The emitted wavelength can be selected by altering the energy of the excited electron beam and therewith controlling the penetration depth to reach the phosphor layer with the desired wavelength.
However, the penetra~ion-type picture tubes do not cover the entire perceivable color spectrum. Due to the complicated control electronics of the electron beam acceleration voltage, the control functions in this kind of a picture tube are awkward. Consequently, the penetration picture tube is only used in special applications.
Another recently developed solution is a combination color display with sequential color fields of two pri~ary colors.
In this case, the picture fields for the two primary colors are generated with a single color picture tube complement-ed with color polarizers for color separation and LC color separators for the selection of se~uential color fields (1, 14). However, the scale of hues in this display i5 limited to the scale of the two primary colors and their combinations. In this system, generating a color picture without flicker presupposes that the LC color separator, in this case the polarization separator, is capable of operating at a frequency of about 100...120 Hz. The-turn-on and turn-off times of the LC cell, described in reference ~1), are about 1 ms. This is sufficient for fulfilling this requirement. The basic limitation~ of this solution are the restricted spectrum of colors within the combinations of the two primary color components and the high intensity loss which is due to the low transmission efficiency in the polarizer.
In a color picture projection display, the color picture is generally the addition of the separately generated ~3b. ;~' ~5 ~ ~ 7 ~i3 primary color pictures from the primary color channels.
These are combined in an optical lens system tha~ projects the primary color pictures on a single screen (13).
The color display method according to the invention aims to eliminate the disadvantages found in the conventional solutions mentioned above and to propose a completely new method and solution for providing color control in the color elements of a display, comprising a light source system and picture elements formed by light gates.
In accordance with the present invention, the 'Synchrogate' method implements the color control of picture elements in a color display with light gates, synchronized to sequential primary color pulses, which are individually generated in the incorporated light source system. Consequently, the light gates act as transmission-controlled switches for the rear-projecting light source in the systemO The transmission of a light gate is driven to proper level for the activation time of the primary color component to correspond to the intensity of the primary color component in the added color spectrum of the picture element. The primary c~lors are generated in the light source system as individual short pulses of colored light, sequentially pulsed at a rate which is sufficiently high for the continuous, flicXer-free perception of the added color from the picture element. The 'Synchrogate' method facilitates the generation of added colors by one light gate for each pixel, providing perfect color convergence.
The Synchrogate color display in accordance with the present invention comprises in its "direct view" mode a display screen with a matrix of light-gate-type picture elements or a group of light gates, a light source system at the rear of the display for generating the primary color light pulses, and a synchronization circuit for controlling these basic elements synchronously by control circuits.
- 7 In the 'projection' mode, the Synchroyate display comprises the light source system, ~ light ~ate matrix, their control circuits, and an optical system for projecting the image, generated in the light gate system, on a separate projection screen.
In accordance with a particular embodiment of the invention there is provided a method for using video signal lines for generating picture elements with individual color control on a color display screen, using at least two light gates and a common light source system for the light gates, and emitting separately at least two primary colors. The light source system is activated separately for each primary color to generate a switched light source that incorporates the diferent primary color components, and each control circuit is used for controlling the transmission of each ligh-t gate to achieve the desired color intensity. The method consists of the steps of generating a primary color component in the light source system as alternating light cycles, and emitting one primary color at a time, with a repetition frequency of at least 25 Hz.
Each picture element color is generated by adjusting the transmission of each light gate synchronously with a primary color emission cycle of each primary color component in a ratio required to generate the desired additive color perception. A basic sequence of each video signal line cycle is divided by -the number of primary colors to provide a corresponding number of sequential sub-sequences, and each sub-sequence is further divided into basic operating cycles ti and ta. ti is used for transferring the video signal information to each light qate and ta ~ ~5~?~7~
- 7a -is used for activating the light source system to generate a light pulse of the corresponding primary color.
In accordance with a particular embodiment of an apparatus for carrying out the above method, there is provided a color display including at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of ¦ each light gate according to desired control signals. The color display includes a synchroniz-ation section, constructed to activate the primary colors of the light source system individually and sequentially at a repetltion frequency of at least 25 Hz. The light source system comprises a vacuum fluorescent construction with emitting primary color I areas for emitting the different primary colors.
Control circuits are constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate. Means are provided for dividing a basic sequence of each cycle of light I transmitted through the light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and for dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for transferring signal - 7b -information to each light gate and using -ta for activating the light source system to generate a light pulse of the corresponding prirnary color.
~y means of the invention, considerable advantages are obtained. Thus, the color convergence is inherently perfect since all basic color components are controlled by the same light gate. This cannot be achieved in any display with adjacent primary color elements. When the same light gate is used for each primary color as the controlled picture I element, a triplet, in practice even grea-ter trans-j mission is obtained, compared to a picture element ¦ comprising adjacent color elements. This has the ¦ added advantage that each primary color source is activated only for the duration of the corresponding primary color component of the picture element. In ¦ accordance with the invention, the method provides a light transmission efficiency exceeding in triple the efficiency of displays with adjacent color elements.
The color purity or monochromaticity of a primary color genera-ted by filtering from a continuous spectrum source is generally worse than that from a monochromatic light source. Consequently, the method according to the invention provides the addi tional advantage of a larger coverage of hues in the color coordinate system. Moreover, one o~ the advantages of the sys~em is the reduction of individual-ly controlled light gate elements to one third (1/3), when compared with the solution based on adjacent color elements. This simpli~ies the light gate matrix construction.
The light gate matrix of the Synchrogate display also disposes with the color filters in the light gate matrix.
Compared to the solution with adjacent light gates, the light gates in this invention are required to operate at approximately triple rate, which is, however, achievable with state-of-art light gate constructions. For instance, the light gate types indicated in references 2, 3, 15, 19, 20 have sufficient speed for this purpose.
These advantages are shown together with other advantages and characteristics in Tables 1 and ~, supplemented as appendices, in which the Synchrogate display is compared to prior-art color displays, based on the combination of a light gate and a light source. The comparison includes display solutions of reference publications (4 and 1), the former being a parallel color display with adjacent light gate elements and filters and the latter a field-sequential color display in which the alternate primary color fields are separated with a liyht gate. The display solution presented in reference publication (17), comprising the combination of a color-selectable light source at the rear and a light gate display, ~s not a functionalj color display but rather a monochrome display with a selection facility for display color by changing the color of the projecting light source at the rear.
The term critical flickex frequency in the comparison table in conjunction with Synchrogate and field-sequential displays refers to the repetition rate of light or picture fields, at which the human eye integrates the repetiti~e light or images into a continuous light or image informa-tion. In practice, the critical flicker frequency depends on the brightness, surface type, contrast, and observer-related S~.-3~
factors of the light or image. Typically the critical flicker frequency is in excess of 25 Hz, see reference ( 1 ~ ) O
The invention will be examined in more detail in the following with the aid of the exemplifying embodiments in accordance with the attached drawings.
Figures la and lb show in a front and side view one embodiment of the display in accordance with the invention.
Figure 2a shows the block diagram of an embodiment of the display in accordance with the invention.
Figure 2b shows in basic diagram form and in enlarged scale an embodiment of one liquid-crystal light gate drive circuit.
Figure 2c shows in basic diagram form and in enlarged scale an embodiment of one liquid-crystal light gate drive circuit in conjuncion with input latches.
Figure 3a shows the signal timing diagram for the different sections of an embodiment in accordance with the invention during a full horizontal scan.
Figure 3b shows the signal timing diagram for the different components of an embodiment in accordance with the invention during a full horizontal scan in conjunction with input latches.
Figures 4a and 4b show another embodiment in accordance with the invention as a front view and a side view, respectively.
Figures Sa and 5b show a third embodiment in accordance with the invention as a front view and a side view, respectively.
Figures 6a and 6b show a fourth embodiment in accordance with the invention as a front view and a side view, respectively.
Figures 7a and 7b show a fifth embodiment in accordance with the invention as a front view and a side view, respectively.
Figure 8a shows in schematic form an embodiment in accordance with the invention for an application in projection display.
Figure 8b shows the rotating color separation filter in front view for the embodiment shown in Figure 8a.
Figure 9a, 9b, and 9c show an embodiment in accordance with the invention for an application in a so-called hybrid display.
Figures lOa and lOb show a comparison between the areas of color elements on the display screen and associated light gates for a display with adjacent color elements and for a display in accordance with the invention, respectively.
The display device implementing the method according to the invention comprises the basic components shown in Figures la and lb: a light gate matrix 9 and a light source system with primary color light sources 6, 7, and 8, and drive circuits 1...4 that control the synchronous operation o~ the light gate matrix 9 and light source system 6, 7, 8 appropriately according to the method of the invention.
The light gate matrix 9 is implemented with light gate elements 10 that are driven during the generation of the corresponding primary colox picture to a transmission level which corresponds to the intensity of displayed primary color in the picture element. A response time of about or less than 2 ms is required for the light gate element 10. A period of a few milliseconds tiR, tiG, tiB (Figures 3a, 3b) is available for driving the picture ~1 field information into light gate matrix 9. To achieve the highest possible efficiency, the light source 6, 7,
In accordance with a particular embodiment of the invention there is provided a method for using video signal lines for generating picture elements with individual color control on a color display screen, using at least two light gates and a common light source system for the light gates, and emitting separately at least two primary colors. The light source system is activated separately for each primary color to generate a switched light source that incorporates the diferent primary color components, and each control circuit is used for controlling the transmission of each ligh-t gate to achieve the desired color intensity. The method consists of the steps of generating a primary color component in the light source system as alternating light cycles, and emitting one primary color at a time, with a repetition frequency of at least 25 Hz.
Each picture element color is generated by adjusting the transmission of each light gate synchronously with a primary color emission cycle of each primary color component in a ratio required to generate the desired additive color perception. A basic sequence of each video signal line cycle is divided by -the number of primary colors to provide a corresponding number of sequential sub-sequences, and each sub-sequence is further divided into basic operating cycles ti and ta. ti is used for transferring the video signal information to each light qate and ta ~ ~5~?~7~
- 7a -is used for activating the light source system to generate a light pulse of the corresponding primary color.
In accordance with a particular embodiment of an apparatus for carrying out the above method, there is provided a color display including at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of ¦ each light gate according to desired control signals. The color display includes a synchroniz-ation section, constructed to activate the primary colors of the light source system individually and sequentially at a repetltion frequency of at least 25 Hz. The light source system comprises a vacuum fluorescent construction with emitting primary color I areas for emitting the different primary colors.
Control circuits are constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate. Means are provided for dividing a basic sequence of each cycle of light I transmitted through the light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and for dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for transferring signal - 7b -information to each light gate and using -ta for activating the light source system to generate a light pulse of the corresponding prirnary color.
~y means of the invention, considerable advantages are obtained. Thus, the color convergence is inherently perfect since all basic color components are controlled by the same light gate. This cannot be achieved in any display with adjacent primary color elements. When the same light gate is used for each primary color as the controlled picture I element, a triplet, in practice even grea-ter trans-j mission is obtained, compared to a picture element ¦ comprising adjacent color elements. This has the ¦ added advantage that each primary color source is activated only for the duration of the corresponding primary color component of the picture element. In ¦ accordance with the invention, the method provides a light transmission efficiency exceeding in triple the efficiency of displays with adjacent color elements.
The color purity or monochromaticity of a primary color genera-ted by filtering from a continuous spectrum source is generally worse than that from a monochromatic light source. Consequently, the method according to the invention provides the addi tional advantage of a larger coverage of hues in the color coordinate system. Moreover, one o~ the advantages of the sys~em is the reduction of individual-ly controlled light gate elements to one third (1/3), when compared with the solution based on adjacent color elements. This simpli~ies the light gate matrix construction.
The light gate matrix of the Synchrogate display also disposes with the color filters in the light gate matrix.
Compared to the solution with adjacent light gates, the light gates in this invention are required to operate at approximately triple rate, which is, however, achievable with state-of-art light gate constructions. For instance, the light gate types indicated in references 2, 3, 15, 19, 20 have sufficient speed for this purpose.
These advantages are shown together with other advantages and characteristics in Tables 1 and ~, supplemented as appendices, in which the Synchrogate display is compared to prior-art color displays, based on the combination of a light gate and a light source. The comparison includes display solutions of reference publications (4 and 1), the former being a parallel color display with adjacent light gate elements and filters and the latter a field-sequential color display in which the alternate primary color fields are separated with a liyht gate. The display solution presented in reference publication (17), comprising the combination of a color-selectable light source at the rear and a light gate display, ~s not a functionalj color display but rather a monochrome display with a selection facility for display color by changing the color of the projecting light source at the rear.
The term critical flickex frequency in the comparison table in conjunction with Synchrogate and field-sequential displays refers to the repetition rate of light or picture fields, at which the human eye integrates the repetiti~e light or images into a continuous light or image informa-tion. In practice, the critical flicker frequency depends on the brightness, surface type, contrast, and observer-related S~.-3~
factors of the light or image. Typically the critical flicker frequency is in excess of 25 Hz, see reference ( 1 ~ ) O
The invention will be examined in more detail in the following with the aid of the exemplifying embodiments in accordance with the attached drawings.
Figures la and lb show in a front and side view one embodiment of the display in accordance with the invention.
Figure 2a shows the block diagram of an embodiment of the display in accordance with the invention.
Figure 2b shows in basic diagram form and in enlarged scale an embodiment of one liquid-crystal light gate drive circuit.
Figure 2c shows in basic diagram form and in enlarged scale an embodiment of one liquid-crystal light gate drive circuit in conjuncion with input latches.
Figure 3a shows the signal timing diagram for the different sections of an embodiment in accordance with the invention during a full horizontal scan.
Figure 3b shows the signal timing diagram for the different components of an embodiment in accordance with the invention during a full horizontal scan in conjunction with input latches.
Figures 4a and 4b show another embodiment in accordance with the invention as a front view and a side view, respectively.
Figures Sa and 5b show a third embodiment in accordance with the invention as a front view and a side view, respectively.
Figures 6a and 6b show a fourth embodiment in accordance with the invention as a front view and a side view, respectively.
Figures 7a and 7b show a fifth embodiment in accordance with the invention as a front view and a side view, respectively.
Figure 8a shows in schematic form an embodiment in accordance with the invention for an application in projection display.
Figure 8b shows the rotating color separation filter in front view for the embodiment shown in Figure 8a.
Figure 9a, 9b, and 9c show an embodiment in accordance with the invention for an application in a so-called hybrid display.
Figures lOa and lOb show a comparison between the areas of color elements on the display screen and associated light gates for a display with adjacent color elements and for a display in accordance with the invention, respectively.
The display device implementing the method according to the invention comprises the basic components shown in Figures la and lb: a light gate matrix 9 and a light source system with primary color light sources 6, 7, and 8, and drive circuits 1...4 that control the synchronous operation o~ the light gate matrix 9 and light source system 6, 7, 8 appropriately according to the method of the invention.
The light gate matrix 9 is implemented with light gate elements 10 that are driven during the generation of the corresponding primary colox picture to a transmission level which corresponds to the intensity of displayed primary color in the picture element. A response time of about or less than 2 ms is required for the light gate element 10. A period of a few milliseconds tiR, tiG, tiB (Figures 3a, 3b) is available for driving the picture ~1 field information into light gate matrix 9. To achieve the highest possible efficiency, the light source 6, 7,
8 is activated only for the time taR, taG, taB, during which the picture information corresponding to each primary color R, G, B is totally transferred to light gate matrix
9 and light gate elements 10 are controlled for their corresponding transmission levels.
On the basis of prior-art technolo~y, the most straightforward solution for implementing the light gate matrix is a liquid-crystal light gate matrix driven by thin-film transistors, principally much in the same way a~ in prior-art light gate matrices with adjacent, color-filtered ligh~ gate elements.
A display according to the invention can be realized using the following main blocks, shown in Figures 2a and 2b.
Block 1: Video signal memory for converting the input signal into serial form, compatible with the display.
Block 2: Data input drivers for controlling the light gate matrix columns cl...cm.
Block 3: Selectors for light gate matrix rows rl...rn.
Block 4: Timing circuits and power supply.
Block 5: Light source system that comprises of separately activated primary color emitting light sources 6, 7, and 8 for red, green, and blue colors, respectively.
Block 9: LC light gate matrix in which the gate elements 9 are driven by an integral thin-film transistor array.
Block 15 (Figure 2b): The gate electrode G of a thin-film transistor 15, driving an individual light gate element 10, 7~J
is connected to matrix rows rj which are controlled by the row selectors of block 3. The drain electrode D of the thin-film transistor 15 is connected to column linec:
Ci o matrix 9, through which a data driver 2 feeds the intensity information of the corresponding element via the thin-film transistor source electrode S at point 12 to the capacitance formed by the LC element. The other electrode of the liquid crystal element 16 is a common electrode 17.
Block 49: Drivers of the light sources 6, 7, 8 in the lîght source system 5.
The so-called Syncrogate display according to the invention presupposes the following performance by the light gate element 10:
a. response time of < 2 ms, and b. controllable transmission level for all primary color spectrum components.
The response requirement is best fulfilled among the prior-art solutions by PLZT light gates (3, 15) and ferroelectric liquid crystal light gates (19, 20~. The ~-cell (2) also complies with the response requirements. The transmission of the referred cell types is controllable by a transverse electric field across the cell for all primary color components R, G, B.
Due to a lower control voltage among other things, the LC cells have given better yield than the PLZT cells in light gate matrix constructions with a large number of cells. The best results have been achieved with LC matrices driven by thin-film transistors (TFT). In prior-art solutions, each LC element in the light gate matrix i5 typically driven by one TFT whose gate and drain electrodes are connected to row and column lines rj and ci of light gate ~5~?~
matrix 9 (Figure 2b). The drive voltage imposed via each column line Ci is transferred through the channel of the TFT, which is driven conductive by the drive siynal from the row selection line, to the capacitance formed by the LC cell. To increase the cell time constant, the capacitance is generally paralleled with a thin-film capacitor to achieve the 20 ms storage ~ime; typically required for cells in adjacent color element displays. The display solution in accordance with the invention operates even with a matrix cell storage time of 1/3 x 20 ms. Contrasting to this, the response time must be < 5 us as the solutions based on adjacent color element matrices typically manage with a longer response time of c 30 us.
An alternative (Figure 2c) for a cell driven by one thin-film transistor is to include another TFT as an input latch which allows the information ~f the next field to be transfer-red into the matrix during the display of the previous field without interfering with the displayed field. The intensity signal is stored in a capacitor 60 and switched to the light gate element by switching on a thin-film transistor 61 in all primary color elements via an electrode 62.
.
Figure 3a shows the signal ~iming diagram for a display according to the invention, in which the light gate matrix 9 is implemented with the so-called TFT-LC construction (Figure 2a). The control method for matrix 9 is "li~e-at-time". The signal timing is controlled by a timing unit 4 which is synchronized with the input video signal.
The basic operating sequence tt (e.g. 20 ms) comprises three sequential sub-sequences tR, tG, and tB during which the red, green, and blue color subfields are generated.
Furthermore, each of the three sub-sequences comprises two basic operating cycles of which the first ones tiR, tiG~ and tiB transfers the video information of each subfield via column lines cl ..cm to the elements of light gate matrix 9 row (rl---rn) one at a time. The control voltages imposed on ~he LC elements are shown in Figure 3a, waveforms rl, Cl---cm; rn~ cl...cm. The second basic cycles taR, ta~ taB are reserved for light source activation so that the light pulse from the red light source is generated during taR, the green pulse from the green light source during taG, and the blue pulse from the blue light source during ~aB, respectlvely. In addition to the basic cycles, the sub-sequences tR, t&, tB m~lst reserve time for light gate state change tLG and light source turn-off delays TR. ~G, ~B. Figure 3b shows the corresponding sequences, sub-sequences, and basic cycles for a light gate matrix with input memories. In this construction, the basic cycles ta and ti may occur simultaneously. An additional sequence for the input memory enable pulse is required with a duration of the same order as the input write pulse.
The light source system 5 of the display comprises of light sources for primary colors R~ G, and which are indivi-dually controlled for a pulse duration of < 3 ms.
The implementation of primary color sources 6, 7, 8, which must be equally displayed to the observer, can be done using any of the several prior-art light source constructions.
An optimal light source is a transparent, flat-surfaced, and low-profiled light source, emitting the primary colors R, G, and B, and permitting the location of all primary color sources 6, 7, 8 of a typical color display aligned in the observation direction. A light source fulfilling these requirements is, for example, the thin-film electrolu-minescent cell according to the Appendix (21), consisting of an electroluminescent construction (Figures 5a and 5b), produced with thin-film technology on a glass plate 18 as an electroluminescent layer 24 with transparent electrodes 23, 25.
~ 2~
Consequently, in this construction the electroluminescent primary light sources, or EL lamps, are located behind the light gate matrix 9, sandwiched together in the size o~ the light gate matrix. The EL lamps R, G, B can be driven in their resonance mode which sets lower efficiency requirements for them than in the multiplexed EL display.
The primary color sources can also be constructed as shown in Figures 4a, 4b. In this implementation, the emitted light field of the adjacently or parallel located primary color sources 19, 20, 21 is homogenized by a diffuser 22, e.g. a frosted glass, between the light source and the light gate matrix. Each primary color source R, G, B
is configured as a parallel controlled group of light emitting diodes, e.g. as columns 19, 20, 21.
Furthermore, the light source field can be constructed as a vacuum fluorescent emitter, incorporating at a sufficient density strip- or dot-formed areas of each primary color, or a combination of these (Figures 6a, 6b3. In this construc-tion, fluorescent strips 31, 32, 33 are located in parallel for the primary colors R, G, B on a glass plate 18. Spaced from these strips 31, 32, 33 is a cathode structure 50.
The strips 31, 32, 33 and the cathode structure 50 are enclosed in a vacuum package, comprising a diffuser plate 22, seals 30, and spacers 26. The primary-color emitting fluorescent materials are printed as narrow strips over separate anode electrodes 27, 28, 29. The selection of R, G, and B light pulses is made by anode commutation.
In the projector mode (Figures 8a, 8b), the light source 41, 42 is most easily implemented with a single white light emitting source 41, 42, e.g. a xenon gas-discharge lamp which is pulsea to improve the efficiency, and a primary color separation filter 37 on the light transmission path, rotated synchronously with the control signals of the light gate matrix 9.
~ ~5~7~
The filter 37 is rotated by an electric motor 39 via a shaft 38 synchronously with a drive signal from a drive unit 40, controlling the matrix 9. The circular filter plate 37 is divided by black sectors 41 into three transparent filter sections 38, 39, 40 for the three primary colors R, G, B, respectively. The e~itted light from the light source 41 is transmitted via the color separation to a reflector 42 and therefrom via the optical light gate system 43.~.46 as the desired color pattern on a screen 47.
A light source construction comprising monochromatic primary color fluorescent tubes 34, 35, 36 or equivalent neon discharge tubes is shown in Figures 7a, 7b. The rise and decay response requirements on these light sources can be fulfilled using e.g. UV-excited lanthanide-type ~luorescent materials. Also in this case, the function of diffuser 22 is to homogenize the emitting surface intensity for the light gate matrix 9.
The embodiments of the invention described above refer to implementations in accordance with the invention which are based on the use of an LC light gate matrix with integral thin-film transistor control circuitry.
When the desired picture resolution is low, the invention also covers solutions in which the individual picture elements are implemented with discrete light gate elements in a hybrid constructio~, possibly provided with a separate driver circuitry. This implementation allows the use of conventional integrated circuits for the control ~f the light gates as suggested for an instrument panel display, depicted in Figures 9a, 9b, 9c. The support structure in this solution for the light gate matrix is a glass plate 51. An opaque insulating material layer 52 is printed on the surface of the glass plate 51 everywhere except on the areas of the light gate elements. On top of the h~
insulating layer 52, a conductor pattern 53 is printed.
This provides ~he wiring from the light gate element contacts 54 to the control circuit contacts 55.
Both the light elements and the control circuits are attached to the glass plate 51, using surface-mounting technology.
An individual light gate display 56 may consist of separately contacted light gate elements 58 which are driven via signal lines, attached to the light gate display edge.
If the construction is based on PLZT light gate elements, a control voltage of about 1500..200 V is required from the driver circuits 57. They can be of the same type as for EL and plasma displays. A driver circuit of this type typically controls 32 or 64 light gate elements.
Although the implementations described as examples of the embodi~ents in accordance with the invention refer to the use of three primary colors, it is clear that the scope o the invention also covers the use of, for example, two, four or even more primary colors.
Adjncent element Pield-sequential Synchrogate display diaplay display (parallel filter construction) Light source Combination- Combination- Separ~te primary color emitter for color emitting color emitter3 primary color~ picture tube for . 2 primary colors Picture genera- In light gate At light sourc~ In light gate tion matrix matrix Intensity con- Transmission Pixel-level control ~ransmission trol for prima- control of at light gatea control of ry colors light gates light gate3 Separation o~ Filters in l$ght Color polnrizers Inherent in primary colors gate matrix and light gate separate color separator sources ~ynchronous ~one Light gate separa- Primary color operations . tor aubfields of frame in light . gate matrix .
A~ded color Primary color pictur~ emitter control __ Color spectrum All colors within Combinatlon~ of 2 All color~ within primary color primary colors primary color spectrum 3pectrum Color conver- Incomplete Complete Complete ~.Z~ 7~
Adjacent element Field-sequential Synchrogate . di~play display display (parallel f$1ter ~onstruction) _ Number o~ light 3 x number of 1 Number of picture gates picture element8 elements Re5ponse re- ~ 20 ms ~ 3 mg < 2 ms quirement f or light gates _ Control inter- ~ 30 u3 ~ 3 ms ~ 5 us val for a _ _ .
liqht gate __ Field multi- ~P-S)(P/3-S) 1 tp_5)2 plier/primary p2 p2 Refer to Fig. lOa . Refer to Fig lOb
On the basis of prior-art technolo~y, the most straightforward solution for implementing the light gate matrix is a liquid-crystal light gate matrix driven by thin-film transistors, principally much in the same way a~ in prior-art light gate matrices with adjacent, color-filtered ligh~ gate elements.
A display according to the invention can be realized using the following main blocks, shown in Figures 2a and 2b.
Block 1: Video signal memory for converting the input signal into serial form, compatible with the display.
Block 2: Data input drivers for controlling the light gate matrix columns cl...cm.
Block 3: Selectors for light gate matrix rows rl...rn.
Block 4: Timing circuits and power supply.
Block 5: Light source system that comprises of separately activated primary color emitting light sources 6, 7, and 8 for red, green, and blue colors, respectively.
Block 9: LC light gate matrix in which the gate elements 9 are driven by an integral thin-film transistor array.
Block 15 (Figure 2b): The gate electrode G of a thin-film transistor 15, driving an individual light gate element 10, 7~J
is connected to matrix rows rj which are controlled by the row selectors of block 3. The drain electrode D of the thin-film transistor 15 is connected to column linec:
Ci o matrix 9, through which a data driver 2 feeds the intensity information of the corresponding element via the thin-film transistor source electrode S at point 12 to the capacitance formed by the LC element. The other electrode of the liquid crystal element 16 is a common electrode 17.
Block 49: Drivers of the light sources 6, 7, 8 in the lîght source system 5.
The so-called Syncrogate display according to the invention presupposes the following performance by the light gate element 10:
a. response time of < 2 ms, and b. controllable transmission level for all primary color spectrum components.
The response requirement is best fulfilled among the prior-art solutions by PLZT light gates (3, 15) and ferroelectric liquid crystal light gates (19, 20~. The ~-cell (2) also complies with the response requirements. The transmission of the referred cell types is controllable by a transverse electric field across the cell for all primary color components R, G, B.
Due to a lower control voltage among other things, the LC cells have given better yield than the PLZT cells in light gate matrix constructions with a large number of cells. The best results have been achieved with LC matrices driven by thin-film transistors (TFT). In prior-art solutions, each LC element in the light gate matrix i5 typically driven by one TFT whose gate and drain electrodes are connected to row and column lines rj and ci of light gate ~5~?~
matrix 9 (Figure 2b). The drive voltage imposed via each column line Ci is transferred through the channel of the TFT, which is driven conductive by the drive siynal from the row selection line, to the capacitance formed by the LC cell. To increase the cell time constant, the capacitance is generally paralleled with a thin-film capacitor to achieve the 20 ms storage ~ime; typically required for cells in adjacent color element displays. The display solution in accordance with the invention operates even with a matrix cell storage time of 1/3 x 20 ms. Contrasting to this, the response time must be < 5 us as the solutions based on adjacent color element matrices typically manage with a longer response time of c 30 us.
An alternative (Figure 2c) for a cell driven by one thin-film transistor is to include another TFT as an input latch which allows the information ~f the next field to be transfer-red into the matrix during the display of the previous field without interfering with the displayed field. The intensity signal is stored in a capacitor 60 and switched to the light gate element by switching on a thin-film transistor 61 in all primary color elements via an electrode 62.
.
Figure 3a shows the signal ~iming diagram for a display according to the invention, in which the light gate matrix 9 is implemented with the so-called TFT-LC construction (Figure 2a). The control method for matrix 9 is "li~e-at-time". The signal timing is controlled by a timing unit 4 which is synchronized with the input video signal.
The basic operating sequence tt (e.g. 20 ms) comprises three sequential sub-sequences tR, tG, and tB during which the red, green, and blue color subfields are generated.
Furthermore, each of the three sub-sequences comprises two basic operating cycles of which the first ones tiR, tiG~ and tiB transfers the video information of each subfield via column lines cl ..cm to the elements of light gate matrix 9 row (rl---rn) one at a time. The control voltages imposed on ~he LC elements are shown in Figure 3a, waveforms rl, Cl---cm; rn~ cl...cm. The second basic cycles taR, ta~ taB are reserved for light source activation so that the light pulse from the red light source is generated during taR, the green pulse from the green light source during taG, and the blue pulse from the blue light source during ~aB, respectlvely. In addition to the basic cycles, the sub-sequences tR, t&, tB m~lst reserve time for light gate state change tLG and light source turn-off delays TR. ~G, ~B. Figure 3b shows the corresponding sequences, sub-sequences, and basic cycles for a light gate matrix with input memories. In this construction, the basic cycles ta and ti may occur simultaneously. An additional sequence for the input memory enable pulse is required with a duration of the same order as the input write pulse.
The light source system 5 of the display comprises of light sources for primary colors R~ G, and which are indivi-dually controlled for a pulse duration of < 3 ms.
The implementation of primary color sources 6, 7, 8, which must be equally displayed to the observer, can be done using any of the several prior-art light source constructions.
An optimal light source is a transparent, flat-surfaced, and low-profiled light source, emitting the primary colors R, G, and B, and permitting the location of all primary color sources 6, 7, 8 of a typical color display aligned in the observation direction. A light source fulfilling these requirements is, for example, the thin-film electrolu-minescent cell according to the Appendix (21), consisting of an electroluminescent construction (Figures 5a and 5b), produced with thin-film technology on a glass plate 18 as an electroluminescent layer 24 with transparent electrodes 23, 25.
~ 2~
Consequently, in this construction the electroluminescent primary light sources, or EL lamps, are located behind the light gate matrix 9, sandwiched together in the size o~ the light gate matrix. The EL lamps R, G, B can be driven in their resonance mode which sets lower efficiency requirements for them than in the multiplexed EL display.
The primary color sources can also be constructed as shown in Figures 4a, 4b. In this implementation, the emitted light field of the adjacently or parallel located primary color sources 19, 20, 21 is homogenized by a diffuser 22, e.g. a frosted glass, between the light source and the light gate matrix. Each primary color source R, G, B
is configured as a parallel controlled group of light emitting diodes, e.g. as columns 19, 20, 21.
Furthermore, the light source field can be constructed as a vacuum fluorescent emitter, incorporating at a sufficient density strip- or dot-formed areas of each primary color, or a combination of these (Figures 6a, 6b3. In this construc-tion, fluorescent strips 31, 32, 33 are located in parallel for the primary colors R, G, B on a glass plate 18. Spaced from these strips 31, 32, 33 is a cathode structure 50.
The strips 31, 32, 33 and the cathode structure 50 are enclosed in a vacuum package, comprising a diffuser plate 22, seals 30, and spacers 26. The primary-color emitting fluorescent materials are printed as narrow strips over separate anode electrodes 27, 28, 29. The selection of R, G, and B light pulses is made by anode commutation.
In the projector mode (Figures 8a, 8b), the light source 41, 42 is most easily implemented with a single white light emitting source 41, 42, e.g. a xenon gas-discharge lamp which is pulsea to improve the efficiency, and a primary color separation filter 37 on the light transmission path, rotated synchronously with the control signals of the light gate matrix 9.
~ ~5~7~
The filter 37 is rotated by an electric motor 39 via a shaft 38 synchronously with a drive signal from a drive unit 40, controlling the matrix 9. The circular filter plate 37 is divided by black sectors 41 into three transparent filter sections 38, 39, 40 for the three primary colors R, G, B, respectively. The e~itted light from the light source 41 is transmitted via the color separation to a reflector 42 and therefrom via the optical light gate system 43.~.46 as the desired color pattern on a screen 47.
A light source construction comprising monochromatic primary color fluorescent tubes 34, 35, 36 or equivalent neon discharge tubes is shown in Figures 7a, 7b. The rise and decay response requirements on these light sources can be fulfilled using e.g. UV-excited lanthanide-type ~luorescent materials. Also in this case, the function of diffuser 22 is to homogenize the emitting surface intensity for the light gate matrix 9.
The embodiments of the invention described above refer to implementations in accordance with the invention which are based on the use of an LC light gate matrix with integral thin-film transistor control circuitry.
When the desired picture resolution is low, the invention also covers solutions in which the individual picture elements are implemented with discrete light gate elements in a hybrid constructio~, possibly provided with a separate driver circuitry. This implementation allows the use of conventional integrated circuits for the control ~f the light gates as suggested for an instrument panel display, depicted in Figures 9a, 9b, 9c. The support structure in this solution for the light gate matrix is a glass plate 51. An opaque insulating material layer 52 is printed on the surface of the glass plate 51 everywhere except on the areas of the light gate elements. On top of the h~
insulating layer 52, a conductor pattern 53 is printed.
This provides ~he wiring from the light gate element contacts 54 to the control circuit contacts 55.
Both the light elements and the control circuits are attached to the glass plate 51, using surface-mounting technology.
An individual light gate display 56 may consist of separately contacted light gate elements 58 which are driven via signal lines, attached to the light gate display edge.
If the construction is based on PLZT light gate elements, a control voltage of about 1500..200 V is required from the driver circuits 57. They can be of the same type as for EL and plasma displays. A driver circuit of this type typically controls 32 or 64 light gate elements.
Although the implementations described as examples of the embodi~ents in accordance with the invention refer to the use of three primary colors, it is clear that the scope o the invention also covers the use of, for example, two, four or even more primary colors.
Adjncent element Pield-sequential Synchrogate display diaplay display (parallel filter construction) Light source Combination- Combination- Separ~te primary color emitter for color emitting color emitter3 primary color~ picture tube for . 2 primary colors Picture genera- In light gate At light sourc~ In light gate tion matrix matrix Intensity con- Transmission Pixel-level control ~ransmission trol for prima- control of at light gatea control of ry colors light gates light gate3 Separation o~ Filters in l$ght Color polnrizers Inherent in primary colors gate matrix and light gate separate color separator sources ~ynchronous ~one Light gate separa- Primary color operations . tor aubfields of frame in light . gate matrix .
A~ded color Primary color pictur~ emitter control __ Color spectrum All colors within Combinatlon~ of 2 All color~ within primary color primary colors primary color spectrum 3pectrum Color conver- Incomplete Complete Complete ~.Z~ 7~
Adjacent element Field-sequential Synchrogate . di~play display display (parallel f$1ter ~onstruction) _ Number o~ light 3 x number of 1 Number of picture gates picture element8 elements Re5ponse re- ~ 20 ms ~ 3 mg < 2 ms quirement f or light gates _ Control inter- ~ 30 u3 ~ 3 ms ~ 5 us val for a _ _ .
liqht gate __ Field multi- ~P-S)(P/3-S) 1 tp_5)2 plier/primary p2 p2 Refer to Fig. lOa . Refer to Fig lOb
Claims (10)
1. A method using video signal lines for generating picture elements with individual color control on a color display screen, using at least two light gates and a common light source system for the light gates, and emitting separately at least two primary colors, wherein the light source system is activated separately for each primary color to generate a switched light source that incorporates the different primary color components, and by using control circuits for controlling the transmission of each light gate to achieve the desired color intensity, said method comprising:
generating the primary color components in the light source system as alternating light cycles, and emitting one primary color at a time, with a repetition frequency of at least 25 Hz, generating each picture element color by adjusting the transmission of each light gate synchronously with a primary color emission cycle of each primary color component in a ratio required to generate the desired additive color perception; and dividing a basic sequence of each video signal line cycle by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for transferring the video signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
generating the primary color components in the light source system as alternating light cycles, and emitting one primary color at a time, with a repetition frequency of at least 25 Hz, generating each picture element color by adjusting the transmission of each light gate synchronously with a primary color emission cycle of each primary color component in a ratio required to generate the desired additive color perception; and dividing a basic sequence of each video signal line cycle by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for transferring the video signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
2. A method as claimed in claim 1, characterized in that the light source system is activated separately for each of three primary colors.
3. A method as claimed in claim 1, characterized in that the said basic cycles occur in each sub-sequence sequentially.
4. A method as claimed in claim 1, characterized in that the said basic cycles occur in each sub-sequence simultaneously.
5. A method as claimed in claim 1, further comprising utilizing a light gate matrix, and trans-ferring the video signal information to each light gate from a data input driver via column lines in parallel form for one row at a time.
6. A color display including at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according to desired control signals, comprising an improvement wherein the color display includes a synchronization section, constructed to activate the primary colors of the light source system individually and sequentially at a repetition frequency of at least 25 Hz, wherein said light source system comprises a vacuum fluorescent con-struction with emitting primary color areas for emitting the different primary colors;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the -transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the -transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
7. A color display, including:
at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according to desired control signals, comprising an improvement wherein the color display includes a synchronization section, constructed to activate the primary colors of the light source system individually and sequentially at a repetition frequency of at least 25 Hz, wherein the light;
source system comprises a structure of fluorescent tubes;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according to desired control signals, comprising an improvement wherein the color display includes a synchronization section, constructed to activate the primary colors of the light source system individually and sequentially at a repetition frequency of at least 25 Hz, wherein the light;
source system comprises a structure of fluorescent tubes;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
8. A color display, including:
at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according to desired control signals, comprising an improvement wherein the color display includes a synchronization section, constructed to activate the primary colors of the light source system at a repetition frequency of at least 25 hz, wherein a diffuser is disposed in front of the light sources for homogenizing the color emitting field;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according to desired control signals, comprising an improvement wherein the color display includes a synchronization section, constructed to activate the primary colors of the light source system at a repetition frequency of at least 25 hz, wherein a diffuser is disposed in front of the light sources for homogenizing the color emitting field;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
9. A color display, including:
at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according to desired control signals, comprising an improvement wherein the color display includes a synchronization section constructed to activate the primary colors of the light source system at a repetition frequency of at least 25 Hz;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate, wherein the light gate elements comprise discrete components mounted on a glass plate which provides a display conductor substrate and a structural frame; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding numer of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according to desired control signals, comprising an improvement wherein the color display includes a synchronization section constructed to activate the primary colors of the light source system at a repetition frequency of at least 25 Hz;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate, wherein the light gate elements comprise discrete components mounted on a glass plate which provides a display conductor substrate and a structural frame; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding numer of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
10. A color display, including:
at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according -to desired control signals, comprising an improvement wherein the color display includes a synchronization section, constructed to activate the primary colors of the light source system at a repetition frequency of at least 25 Hz;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate, wherein the control circuits for driving an individual light gate include an input memory consisting of a thin-film transistor and a latch capacitor for transferring the picture information simultaneously to all picture elements by a signal on a common enable electrode line for all picture elements; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
at least two light gates as display elements, a light source system at the rear of the display, constructed for emitting at least two different primary colors, and control circuits for controlling the transmission of each light gate according -to desired control signals, comprising an improvement wherein the color display includes a synchronization section, constructed to activate the primary colors of the light source system at a repetition frequency of at least 25 Hz;
control circuits constructed to drive each light gate synchronously with the synchronization section so that when any one of the primary color sources is in the activated state, the transmitted light intensity via the corresponding light gate is respectively proportional to the magnitude of the primary color component in the additive color, generated by the light gate, wherein the control circuits for driving an individual light gate include an input memory consisting of a thin-film transistor and a latch capacitor for transferring the picture information simultaneously to all picture elements by a signal on a common enable electrode line for all picture elements; and means for dividing a basic sequence of each cycle of light transmitted through said light gates by the number of primary colors to provide a corresponding number of sequential sub-sequences, and dividing each sub-sequence further into basic operating cycles ti and ta, and using ti for trans-ferring signal information to each light gate and using ta for activating the light source system to generate a light pulse of the corresponding primary color.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI850874A FI73325C (en) | 1985-03-05 | 1985-03-05 | FOERFARANDE FOER ALSTRING AV INDIVIDUELLT REGLERBARA BILDELEMENT OCH PAO DESSA BASERAD FAERGDISPLAY. |
| FI850874 | 1985-03-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1250976A true CA1250976A (en) | 1989-03-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000503253A Expired CA1250976A (en) | 1985-03-05 | 1986-03-04 | Method for generating electronically controllable color elements and color display based on the method |
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| US (1) | US4907862A (en) |
| JP (1) | JPS61281692A (en) |
| CN (1) | CN86102354A (en) |
| AU (1) | AU593239B2 (en) |
| BE (1) | BE904319A (en) |
| BR (1) | BR8600925A (en) |
| CA (1) | CA1250976A (en) |
| CH (1) | CH672196A5 (en) |
| DD (1) | DD243578A5 (en) |
| DE (1) | DE3606404A1 (en) |
| DK (1) | DK97686A (en) |
| ES (1) | ES8707804A1 (en) |
| FI (1) | FI73325C (en) |
| FR (1) | FR2578705B1 (en) |
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| IN (1) | IN165865B (en) |
| IT (1) | IT1190215B (en) |
| NL (1) | NL8600540A (en) |
| NO (1) | NO860801L (en) |
| SE (1) | SE461692B (en) |
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-
1986
- 1986-02-27 DE DE19863606404 patent/DE3606404A1/en not_active Withdrawn
- 1986-02-27 GB GB8604906A patent/GB2172733B/en not_active Expired
- 1986-03-03 BE BE1/011446A patent/BE904319A/en not_active IP Right Cessation
- 1986-03-04 IT IT47713/86A patent/IT1190215B/en active
- 1986-03-04 CA CA000503253A patent/CA1250976A/en not_active Expired
- 1986-03-04 BR BR8600925A patent/BR8600925A/en unknown
- 1986-03-04 CH CH877/86A patent/CH672196A5/de not_active IP Right Cessation
- 1986-03-04 AU AU54279/86A patent/AU593239B2/en not_active Ceased
- 1986-03-04 FR FR8603019A patent/FR2578705B1/en not_active Expired - Fee Related
- 1986-03-04 NO NO860801A patent/NO860801L/no unknown
- 1986-03-04 SE SE8600983A patent/SE461692B/en not_active IP Right Cessation
- 1986-03-04 NL NL8600540A patent/NL8600540A/en not_active Application Discontinuation
- 1986-03-04 DD DD86287553A patent/DD243578A5/en not_active IP Right Cessation
- 1986-03-04 DK DK97686A patent/DK97686A/en not_active Application Discontinuation
- 1986-03-05 ES ES552660A patent/ES8707804A1/en not_active Expired
- 1986-03-05 IN IN164/CAL/86A patent/IN165865B/en unknown
- 1986-03-05 JP JP61046446A patent/JPS61281692A/en active Pending
- 1986-03-05 CN CN198686102354A patent/CN86102354A/en active Pending
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1989
- 1989-04-18 US US07/341,236 patent/US4907862A/en not_active Expired - Lifetime
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| DD243578A5 (en) | 1987-03-04 |
| SE8600983L (en) | 1986-09-06 |
| FI850874A0 (en) | 1985-03-05 |
| FI73325C (en) | 1987-09-10 |
| FR2578705A1 (en) | 1986-09-12 |
| DK97686D0 (en) | 1986-03-04 |
| NL8600540A (en) | 1986-10-01 |
| GB2172733A (en) | 1986-09-24 |
| CN86102354A (en) | 1986-12-03 |
| US4907862A (en) | 1990-03-13 |
| DK97686A (en) | 1986-09-06 |
| BR8600925A (en) | 1986-11-11 |
| AU593239B2 (en) | 1990-02-08 |
| CH672196A5 (en) | 1989-10-31 |
| ES8707804A1 (en) | 1987-08-16 |
| AU5427986A (en) | 1986-09-11 |
| SE8600983D0 (en) | 1986-03-04 |
| NO860801L (en) | 1986-09-08 |
| IN165865B (en) | 1990-02-03 |
| IT8647713A0 (en) | 1986-03-04 |
| DE3606404A1 (en) | 1986-09-11 |
| ES552660A0 (en) | 1987-08-16 |
| GB8604906D0 (en) | 1986-04-03 |
| FI850874L (en) | 1986-09-06 |
| IT1190215B (en) | 1988-02-16 |
| SE461692B (en) | 1990-03-12 |
| FI73325B (en) | 1987-05-29 |
| BE904319A (en) | 1986-09-03 |
| GB2172733B (en) | 1989-11-22 |
| JPS61281692A (en) | 1986-12-12 |
| FR2578705B1 (en) | 1990-10-19 |
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