EP1347434A1 - Contrast and brightness control of a display - Google Patents
Contrast and brightness control of a display Download PDFInfo
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- EP1347434A1 EP1347434A1 EP02076072A EP02076072A EP1347434A1 EP 1347434 A1 EP1347434 A1 EP 1347434A1 EP 02076072 A EP02076072 A EP 02076072A EP 02076072 A EP02076072 A EP 02076072A EP 1347434 A1 EP1347434 A1 EP 1347434A1
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- contrast
- brightness
- display panel
- display
- video
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- 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
- G09G3/22—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 using controlled light sources
- G09G3/28—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 using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
- G09G3/288—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 using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
- G09G3/291—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 using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes
- G09G3/294—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 using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes for lighting or sustain discharge
- G09G3/2944—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 using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes for lighting or sustain discharge by varying the frequency of sustain pulses or the number of sustain pulses proportionally in each subfield of the whole frame
-
- 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
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
- G09G2320/0276—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0606—Manual adjustment
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0626—Adjustment of display parameters for control of overall brightness
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/066—Adjustment of display parameters for control of contrast
-
- 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
- G09G3/2007—Display of intermediate tones
- G09G3/2018—Display of intermediate tones by time modulation using two or more time intervals
- G09G3/2022—Display of intermediate tones by time modulation using two or more time intervals using sub-frames
-
- 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
- G09G3/2007—Display of intermediate tones
- G09G3/2044—Display of intermediate tones using dithering
-
- 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
- G09G3/2007—Display of intermediate tones
- G09G3/2077—Display of intermediate tones by a combination of two or more gradation control methods
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Power Engineering (AREA)
- Plasma & Fusion (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Control Of Gas Discharge Display Tubes (AREA)
Abstract
Controlling contrast and brightness of a display panel (1) by means
of either a gamma correction unit or a timing and control unit by
controlling luminance of the display panel by varying a number of
sustain pulses per second.
Description
The present invention relates to the control of a display, and more particularly
to contrast and brightness control of a display.
Today, many different types of displays exist. When looking at a display
sometimes a user wants to adjust brightness and/or other settings of the display to get a better
picture. Sometimes it is possible to change the environment instead, for instance to create a
dimmed environment. Often a combination of adjusted settings and environmental conditions
is used. Typical parameters that can be changed in the display are contrast and brightness. In
common (digital) display systems, contrast and brightness can be regulated in the video
stream before a gamma compensation has been performed. This can be represented by a
formula, which includes gamma:
Lout ={B + C*(Videoin /2n -1)}y
where
Videoin = digital video input signal
Lout = Luminance, light from display
B = Brightness offset ( 0 < B < 1, typical default B=0 )
C = Contrast factor ( 0 < C, typical default C=1 )
n = Resolution (number of bits, typical default n=8)
y = Gamma value (1 < y < 3, typical default y=2.4)
Videoin = digital video input signal
Lout = Luminance, light from display
B = Brightness offset ( 0 < B < 1, typical default B=0 )
C = Contrast factor ( 0 < C, typical default C=1 )
n = Resolution (number of bits, typical default n=8)
y = Gamma value (1 < y < 3, typical default y=2.4)
In a Plasma Display Panel, (PDP), a control unit can be used for controlling
the consumed electric power of a display, for instance so that a brightness level is forcibly
lowered to suppress consumption of power below a predetermined level. An Automatic
Power Control (APC) unit avoids overloading the PDP (the panel and the power-supply of
the PDP). In a conventional APC unit, typically the consumption of electric power is detected
by detecting a mean current flowing through a high voltage power source that drives the
PDP. Typically, the detected current value is compared to a reference value and periodically
the APC unit modifies signals driving the PDP.
US-A-5 956 014 describes an analog brightness value set by a variable resistor
that is converted into a digital brightness value.
When the APC unit is limiting the luminance of the PDP, contrast and
brightness settings in the video stream will not have a predictable effect, while the APC unit
will regulate to a new setting. This implies that optimal display performance cannot be
obtained.
It is an object of the invention to provide a method and apparatus for a display
by which contrast and brightness control is improved. The invention is defined by the
independent claims. The dependent claims define advantageous embodiments.
According to a first embodiment of the present invention, the object is realized
by implementing contrast and brightness control in the video stream as a programmable
Color LookUp Table (CLUT) unit, typically combining it with existing gamma and color
point functions. This reduces the hardware cost and improves processing accuracy, since one
quantization step can be omitted.
According to a second embodiment of the present invention, the object is
realized by implementing contrast and brightness control independent from the video
processing, close to the display.
According to a third embodiment of the invention, contrast and brightness are
implemented in an existing power control unit, typically an APC unit that controls luminance
of the display panel, typically a PDP. This provides optimal display performance with only
little extra hardware cost. Furthermore, digital video processing is not affected since the unit
is separated from the video processing.
According to a fourth embodiment of the invention, contrast and brightness
regulations are performed in the APC unit by varying the number of sustain pulses per
second. In this way, new settings will have a predictable effect.
Preferably, the brightness of the display panel is set by increasing or
decreasing the number of sustain pulses (per time period) to a given sub-field of the display
panel in accordance with a given brightness value.
These and other aspects of the invention will be apparent from and elucidated
with reference to the embodiments(s) described hereinafter.
The present invention will be more clearly understood from the following
description of the preferred embodiments of the invention read in conjunction with the
attached drawings, in which:
A PDP device, plasma display controller and plasma display driving method
according to various embodiments of the present invention will now be described in detail
with reference to the accompanying drawing figures.
In the following, a PDP device will be described; however it should be noted
that this is only an example of a display type. Other types of displays typically other sub-field
driven displays, for instance liquid crystal displays (LCDs) etc are also within the scope of
the invention as set out in the claims.
A user is often equipped with a set of controls to adjust a display to a specific
environment or to adjust video processing to personal preferences. In some displays, an
automated process, driven by data from sensors might take care of the adjustment of the
display for specific environmental conditions. Other displays will require the user to give
feedback via the user controls. However, besides these adjustments, a user may like to
change some settings to match with personal preferences, examples are for instance: color
saturation, more contrast at specific grey-levels (for instance to see the back-ground of a
horror-scene), histogram control or color-point (to get a warm or cool impression of an
image). These are typical video processing features not correlated to environmental
conditions.
The image quality of a PDP device depends on parameters such as: black-level,
contrast ratio (dark room/dim surround/daylight), dynamic peak white (small area and
short time), average peak white (large area and continuous), white point (e. g. D65), number
of displayable grey-levels, and dithering. Contrast and brightness control are user settings,
influencing the luminance and contrast ratio. This will be described below with reference to
accompanying drawing figures 1-4.
In Fig. 1 it is illustrated a PDP 1 generating light (illustrated by arrows going
out from the PDP). The contrast ratio (CR) follows the formula:
CR = Lmax /Lmin
where Lmin = minimum Luminance (light).
Lmax = maximum Luminance (light).
Lmax = maximum Luminance (light).
In Fig. 2, the PDP reflects incident light (Lin) as reflected light (Lref). The
reflection ratio (r) can be represented in a formula:
r = Lref /Lin < 1
In Fig. 3 the PDP generating and reflecting light is illustrated, whereby CR can
be represented by a formula :
CR= n*(Lmax + n*r*Lin )/n*(Lmin + n*r*Lin )
where
n = filter plate transparency < 1.
n = filter plate transparency < 1.
If, as illustrated in Fig. 4, a PDP also is under the influence of ambient light
(Lamb), CR can be represented by a formula as follows:
CR = {n*(Lmax + n*r*Lin ) + x*(Lamb)} / {n*(Lmin n*r*Lin ) + x*(Lamb )}
where
x = part of ambient light which affects the perception ( 0 < x < 1)
x = part of ambient light which affects the perception ( 0 < x < 1)
The formulas (III) - (V) show that Lin and Lamb reduce the theoretical CR.
Moreover, they also show that Lmin should be kept as small as possible (generate less light
during address and erase phase). Lref can be reduced by reducing n in front of the panel, but
this also reduces L' = n*Lmax . Lin and Lamb can be reduced by operating in a dimmed
environment, i. e. closed curtains for instance.
A method of controlling a display panel according to a preferred embodiment
of the invention will now be discussed. The method comprises the step of providing manual
contrast and/or brightness control by controlling the luminance of the display panel.
This will be further described in the next formulas, which compare the effects
of contrast and brightness regulation with processing in the video versus processing in the
luminance domain:
Lout = {B + C*(Videoin /2n -1)}y = B' + C'*(Videoin /2n -1)y
Assuming y=2 and B'= B2, C'= C2, the formula becomes:
Lout = {B + C*(Videoin /2n -1)}2 = B2 + C2 *(Videoin /2n -1)2
Lout = B2 + 2BC*(Videoin /2n -1) + C2 *( Videoin /2n -1)2 = B2 + C2 *(Videoin /2n -1)2
Ldif = 2BC*( Videoin /2n -1)
When the brightness control B=0, the luminance difference Ldif = 0.
It can be proven that when B=0 it does not matter whether contrast processing is done in
video or luminance domain.
Preferably, the luminance of the display panel is controlled according to the
formula:
Videoout = (2n -1) * {B + C*(Videoin /2n -1)}
where
Videoin = digital video input signal
Lout = Luminance, light from display
B = Brightness offset
C = Contrast factor
n = Resolution
y = Gamma value
or in an existing gamma correction unit, according to the formula:Lout ={B + C*(Videoin /2n -1)}y
Videoin = digital video input signal
Lout = Luminance, light from display
B = Brightness offset
C = Contrast factor
n = Resolution
y = Gamma value
or in an existing gamma correction unit, according to the formula:
The control can also provided according to an alternative formula:
Lout = {B + C*(Videoin /2n -1) - (D* |(Videoin /2n -1)- E | }y
A preferred embodiment of the invention will now be described, with
reference to Fig. 5, in which it is illustrated how contrast/brightness control is provided in the
video stream.
In Fig. 5 is a block diagram illustrating a preferred embodiment of a display
system 10, provided with a PDP 1, a contrast/brightness controller 3, an automatic power
control unit 4, a sub-field processor 2, a dithering unit 5, and a gamma unit 6.
To reduce hardware requirement and to improve processing accuracy, contrast
and brightness control can be combined with the gamma processing. It can be implemented
as one LUT 8. Its content can be calculated off-line by a µ-controller (not shown) and
downloaded into the LUT 8.
A user might like to have the classic controls available, even if they would not
be required for an optimal adjustment of the display. For PDP devices this would be the
brightness control. To provide a user with a control, which will not deteriorate the image-quality,
the classic effect can be replaced by another effect. For instance, it is possible to use
a slight modification of the LUT content to provide more contrast in the dark areas of a
scene, at the cost of contrast in the brighter areas.
In this case a user-controlled video-dependent luminance component is added
to the normal luminance due to gamma to get a modified gamma curve which results in a
higher contrast in darker areas (steeper gamma curve) and less contrast for brighter areas
(less steep gamma curve).
An alternative embodiment of the invention will now be described, with
reference to Fig. 6, in which it is illustrated how contrast/brightness control is provided in an
automatic power control (APC) unit.
Fig. 6 is a block diagram illustrating a preferred embodiment of a display
system 10, in the following referred to as a "display", according to another embodiment of
the invention. The display 10 comprises a PDP 1 having display cells arranged in a X-Y
orthogonal matrix, a processor unit 2, a contrast/brightness controller 3 and an automatic
power control unit 4.
The PDP 1 is of conventional type and will therefore not be described in more
detail since PDPs are well known. The contrast/brightness controller 3 is connected to the
automatic power control unit 4, or can be a part of the same. Also software-only solutions are
possible, provided that the contrast/brightness controller 3 is adjacent to or part of the power
control unit 4.
In an AC-type PDP device, the data to be displayed is written for every line,
and then the PDP is maintained by sustain discharges. The brightness of the PDP varies in
proportion to the number of sustain discharges per time interval, and hence the brightness can
be changed by the number of sustain discharges.
The automatic power control unit 4 modulates the consumed power of a
display, in this embodiment the PDP 1. The generated light is regulated by changing the
number of sustain pulses per second to the PDP. After image load of a frame has been
determined, the light generated by the image can be amplified or attenuated, save guarding
the PDP.
In a conventional PDP device, in case the APC unit is attenuating the image to
reduce the power consumption or temperature, the luminance of the image is reduced. In this
case, a user might try to change contrast/brightness settings to increase the luminance. When
amplifying the video-data, the APC unit would immediately attenuate the image
representation, back to the initial level but at reduced quality. This can be avoided by
providing the contrast/brightness settings to the automatic power control unit according to the
invention as implemented in the embodiment shown in Fig. 6.
Preferably, according to another preferred embodiment of the invention, the
controller 3 can be arranged to provide for a user to set parameters to satisfy the user.
In this way, the digital video processing is not affected by the user-controllable
contrast and brightness settings, since the settings are implemented after the processing has
been performed in the processor 2. Therefore, it is possible to exploit the full available
dynamic range for video data processing.
According to another preferred embodiment of the invention, the contrast and
brightness of the PDP are set by increasing or decreasing the number of sustain pulses (per
time period) to a given sub-field of the PDP 1 in accordance with the given values. This is a
very accurate control mechanism, which gives an optimal and predictable adjustment.
An offset in the video-level due to brightness control according to formula
Lout ={B + C*(Videoin /2n -1)}y
will generate a small color saturation artifact with respect to original image. This is not
important when the brightness is adjusted to the black level of the display (for CRT the
offset-current of an electron gun should be adjusted to get a just-noticeable video level "1").
Driving sustain pulses to a fully addressed display gives the effect of a classic brightness
control. This can be achieved by addressing all lines at once instead of one-by-one, saving
time.
For PDP, the brightness is typically set to "0", while a minimum luminance
pixel is already clearly visible.
Amplifying the sustain level of sub-fields (C) resembles the effect of a
contrast regulation. It can be noted that these variations are performed in the luminance
domain instead of the video domain, however this has no impact.
Since the contrast/brightness controller 3 is implemented in the automatic
power control unit 4, preferably in a timing and control unit of the same (not shown), it can
provide an optimal display performance, driven by software, with only little extra hardware
cost.
When contrast and brightness control is done in the timing and control
process, various timing aspects can be included. Temporary driving the display above the
recommended automatic power control level can provide a better match with the user's
demands.
Often a display supports a limited number of grey-levels, combined with
dithering. When user-control and APC regulate the video level, for each pixel a course
stepwise variation of the video level is calculated. The dynamic range of the video-data must
allow increasing video-levels. In case of a user-control and APC regulating the sustain-level,
variations on the sustain level step-size will cause variations of image representation at a
more accurate resolution. In this case the video processing chain is independent of binary
distributed sub-field weights. For Example: Video levels 1-2-4-8-16-64-128 related to e. g.
4-8-16-32-64-128-256-512 sustain pulses. 25 % reduction implies the following sustain
levels: 3-6-12-24-48-96-192-384.
10 % reduction (combined with temporal sustain dithering): 3,6-7,2-14,4-28,8-57,6-115,2-230,4
sustain pulses.
The invention can be realized by controlling contrast and brightness in a
display panel by means of either a gamma correction unit, controlling luminance of the
display panel by varying video levels, an automatic power control unit, already controlling
luminance of the display panel by varying a number of sustain pulses per second, or a timing
and control unit, controlled by software process which is already controlling luminance of the
display panel by varying a number of sustain pulses per second.
It should be noted that the above-mentioned embodiments illustrate rather than
limit the invention, and that those skilled in the art will be able to design many alternative
embodiments without departing from the scope of the appended claims. In the claims, any
reference signs placed between parentheses shall not be construed as limiting the claim. The
word "comprising" does not exclude the presence of elements or steps other than those listed
in a claim. The word "a" or "an" preceding an element does not exclude the presence of a
plurality of such elements. The invention can be implemented by means of hardware
comprising several distinct elements, and by means of a suitably programmed computer. In
the device claim enumerating several means, several of these means can be embodied by one
and the same item of hardware. The mere fact that certain measures are recited in mutually
different dependent claims does not indicate that a combination of these measures cannot be
used to advantage.
Claims (12)
- A method of controlling a display panel, said method comprising the step of:providing manual contrast and/or brightness control by controlling the luminance of the display panel.
- A method according to claim 1, wherein the contrast and/or brightness of the display panel is set by increasing or decreasing the video-level to a given pixel of the display panel in accordance with a given value, processed by a programmable lookup table, combined with gamma correction function.
- A method according to claim 1, further comprising the step of:implementing contrast/and brightness control independent from video processing, close to the display.
- A method according to claim 3, wherein the control is provided in an existing automatic power control unit.
- A method according to claim 1, wherein the contrast and/or brightness of the display panel is set by increasing or decreasing the number of sustain pulses (per time period) to a given sub-field of the display panel in accordance with a given value, preferably processed by software, and preferably combined with automatic power control function.
- A method according to claim 5, wherein the brightness control is achieved by controlled light generation on the complete panel, during the erase phase of a display panel, typically a PDP.
- A method according to claim 1, wherein the control is provided in an existing timing and control unit.
- A method according to claim 5, wherein the contrast and/or brightness regulation is combined with a timing and control function.
- A contrast/brightness controller for controlling a display panel, arranged to provide manual contrast and/or brightness control by controlling the luminance of the display panel.
- A contrast/brightness controller according to claim 9, wherein the controller is connected to or part of an automatic power control unit.
- A contrast/brightness controller according to claim 10, arranged to control the luminance by increasing or decreasing the number of sustain pulses to a given sub-field of the display panel.
- A display comprising a display panel, a sub-field processor, an automatic power control unit and a contrast brightness controller according to claim 9.
Priority Applications (1)
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EP02076072A EP1347434A1 (en) | 2002-03-18 | 2002-03-18 | Contrast and brightness control of a display |
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EP02076072A EP1347434A1 (en) | 2002-03-18 | 2002-03-18 | Contrast and brightness control of a display |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1624678A1 (en) * | 2004-03-05 | 2006-02-08 | Matsushita Electric Industries Co., Ltd. | Image signal processing method, image signal processing apparatus, and image displaying apparatus |
EP1796064A1 (en) * | 2005-12-12 | 2007-06-13 | Deutsche Thomson-Brandt Gmbh | Apparatus for driving a plasma display panel with APL pre-measurement and corresponding method |
EP1796065A1 (en) * | 2005-12-12 | 2007-06-13 | Thomson Licensing | Apparatus for driving a plasma display panel with APL pre-measurement and corresponding method |
EP1821277A2 (en) * | 2006-02-20 | 2007-08-22 | Thomson Licensing | Method for driving plasma display panel with attenuation estimation and compensation and corresponding apparatus |
CN100423050C (en) * | 2003-10-16 | 2008-10-01 | 三星Sdi株式会社 | Plasma display panel device, white linearity control device and control method thereof |
CN113870746A (en) * | 2021-09-23 | 2021-12-31 | 北京德为智慧科技有限公司 | Display testing method, display, terminal equipment and storage medium |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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EP0811963A1 (en) * | 1996-06-06 | 1997-12-10 | Hitachi, Ltd. | Plasma display device and driving method |
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Cited By (14)
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CN100423050C (en) * | 2003-10-16 | 2008-10-01 | 三星Sdi株式会社 | Plasma display panel device, white linearity control device and control method thereof |
US7649507B2 (en) | 2003-10-16 | 2010-01-19 | Samsung Sdi Co., Ltd. | Plasma display panel device, white linearity control device and control method thereof |
EP1624678A1 (en) * | 2004-03-05 | 2006-02-08 | Matsushita Electric Industries Co., Ltd. | Image signal processing method, image signal processing apparatus, and image displaying apparatus |
US7439984B2 (en) | 2004-03-05 | 2008-10-21 | Matsushita Electric Industrial Co., Ltd. | Image signal processing method, image signal processing apparatus, and image displaying apparatus |
EP1624678A4 (en) * | 2004-03-05 | 2007-10-10 | Matsushita Electric Ind Co Ltd | Image signal processing method, image signal processing apparatus, and image displaying apparatus |
CN1983361B (en) * | 2005-12-12 | 2010-06-30 | 汤姆森许可贸易公司 | Apparatus for driving plasma display panel with APL pre-measurement and corresponding method |
EP1796065A1 (en) * | 2005-12-12 | 2007-06-13 | Thomson Licensing | Apparatus for driving a plasma display panel with APL pre-measurement and corresponding method |
EP1796064A1 (en) * | 2005-12-12 | 2007-06-13 | Deutsche Thomson-Brandt Gmbh | Apparatus for driving a plasma display panel with APL pre-measurement and corresponding method |
US8125500B2 (en) | 2005-12-12 | 2012-02-28 | Thomson Licensing | Apparatus for driving a plasma display panel with APL pre-measurement and corresponding method |
TWI411995B (en) * | 2005-12-12 | 2013-10-11 | Thomson Licensing | Apparatus for driving a plasma display panel with apl pre-measurement and corresponding method |
EP1821277A2 (en) * | 2006-02-20 | 2007-08-22 | Thomson Licensing | Method for driving plasma display panel with attenuation estimation and compensation and corresponding apparatus |
EP1821277A3 (en) * | 2006-02-20 | 2010-02-17 | Thomson Licensing | Method for driving plasma display panel with attenuation estimation and compensation and corresponding apparatus |
CN113870746A (en) * | 2021-09-23 | 2021-12-31 | 北京德为智慧科技有限公司 | Display testing method, display, terminal equipment and storage medium |
CN113870746B (en) * | 2021-09-23 | 2024-03-01 | 北京德为智慧科技有限公司 | Display testing method, display, terminal equipment and storage medium |
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