CN100456350C - Image processing method, display device and its driving method - Google Patents

Image processing method, display device and its driving method Download PDF

Info

Publication number
CN100456350C
CN100456350C CNB2005100094476A CN200510009447A CN100456350C CN 100456350 C CN100456350 C CN 100456350C CN B2005100094476 A CNB2005100094476 A CN B2005100094476A CN 200510009447 A CN200510009447 A CN 200510009447A CN 100456350 C CN100456350 C CN 100456350C
Authority
CN
China
Prior art keywords
vision signal
gray
signal
subframe
image processing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CNB2005100094476A
Other languages
Chinese (zh)
Other versions
CN1822086A (en
Inventor
宫坂大吾
今井雅雄
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hannstar Display Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to CNB2005100094476A priority Critical patent/CN100456350C/en
Publication of CN1822086A publication Critical patent/CN1822086A/en
Application granted granted Critical
Publication of CN100456350C publication Critical patent/CN100456350C/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

The present invention provides a holding type image processing method. The driving method of a display device and the display device driven by the method are used for improving the quality of motion pictures under the situation of no maximum brightness and contrast reduction. Brightness components of a static sub-frame are distributed to other sub-frames in an image processing method that a frame is divided into sub-frames so as to generate the sub-frames of which the brightness component is higher than the mean value of the frame, and the sub-frames of which the brightness component is lower than the mean value of the frame. As a result, the brightness component keeps unchanged before and after the brightness component is distributed in the period of one frame period.

Description

Image processing method, display device and driving method thereof
Technical field
The present invention relates to the image processing method and the driving method thereof of maintenance display device, and the display device that uses this driving method, more exactly, relate to and be used to improve the image processing method of motion picture picture quality (motion picture quality) and the driving method of display device, and the display device that uses this driving method.
Background technology
In recent years, the screen size in the active array type liquid crystal display, demonstration degree of accuracy and unmixed colour purity obtain increasing, and can show the rest image with enough high image qualities.On the other hand, although in showing motion picture, improve picture quality, still there is not to obtain to be equivalent to the picture quality of CRT (cathode-ray tube (CRT)) by increasing liquid crystal response speed.
When motion picture shows is when carrying out by the maintenance display device that includes liquid crystal display, what visually identify during display-object that the observer moves on view screen is the moving target profile that blurs, the moving image quality that the result recognizes descend (hereinafter will be this because display-object on the screen mobile cause visually identifying be that this phenomenon of display-object profile (bluring of motion picture) of bluring is called " edge fog ").
The reason of this motion picture deterioration in the maintenance display device is at the Information and Communication Engineering teacher Ishiguro of electronics research institute, and the technical research report EID 96-4 (1996) of Kurita has in detail in (hereinafter being called non-patent file 1) and tells about.Talk about in non-patent file 1, the deterioration of motion picture quality is by keep (showing same gray level in a frame period continuously) to be caused such as 0 rank in the TFT active components such as (thin film transistor (TFT)s) from the principle in the liquid crystal display.
This shows the deterioration that only can not prevent the motion picture quality by the liquid crystal response speed in the increase liquid crystal display.That is to say that the deterioration of motion picture quality is to be kept causing by 0 rank of display element, and can not avoid by existing driving method.
By increasing the overwrite speed (frame per second) of picture, can improve the impaired condition of motion picture quality.But in the method, need come the original non-existent frame picture of interpolation (picture that shows) between the primitive frame picture by Flame Image Process, the result is difficult to improve the impaired condition of motion picture quality by this method.When frame per second being established when high, the data volume during transmission video signal increases, and therefore this method can't be applied to the insufficient existing broadcast facility of video signal transmission wire capacity.
In order to address the above problem, several method has been proposed, the liquid crystal that wherein has the high-speed response characteristic is used to carry out black replacement (no matter the original gray level value of its predetermined time period in a frame in frame, show black in the pixel), thereby realize that the false pulse type shows, to improve the motion picture quality.
The method of carrying out the black replacement is included in (black is reset and driven) method (the first black remapping method) of the reset voltage that writes corresponding black output in the liquid crystal, the method backlight (the second black remapping method) according to the frame period synchronous flashing, and use with the same direction of driven sweep direction on the method (the 3rd black remapping method) of the optical shutter that moves.The prior art relevant with the first black remapping method is included in (6~7 pages of Japanese patent application 2000-122596, Fig. 7) (hereinafter be called patent file 1) in disclosed " display device " and Japanese patent application 2002-23707 (4~5 pages, Fig. 6) (hereinafter be called patent file 2) in disclosed " display device ".The prior art relevant with the second black remapping method is included among the Japanese patent application 2000-275604 (hereinafter being called patent file 3) disclosed " liquid crystal display ".The prior art relevant with the 3rd black remapping method is included among the Japanese patent application 2002-148712 (hereinafter being called patent file 4) disclosed " projecting liquid crystal displaying equipment ".
Invention disclosed provides the display surface with a plurality of pixel columns in patent file 1, wherein display surface can be during writing at least one of a plurality of pixel columns with image, black is write in other pixel columns, carried out the black replacement, thereby improved the motion picture quality.
Invention disclosed provides the maintenance display device in patent file 2, wherein as the frame of unit interval of being used to Show Picture, be divided into a plurality of subframes on time, and wherein according to the brightness of the picture of input before, the brightness that is input to the picture in the equipment self descends with set rate.The use of this structure of invention disclosed in patent file 2 prevents that picture from thickening when showing motion picture, suppressed the picture lowering of luminance simultaneously.
Invention disclosed provides liquid crystal display in patent file 3, the luminaire that wherein has a plurality of bulbs obtains distributing, and make the set time that response begins constantly from the liquid-crystal display section that is assigned with the zone corresponding to each of luminaire after, in this zone corresponding to being subjected to the control of illumination driver by the bulb of the luminaire of response region and opening, and then through being closed after the set time.This structure has reduced owing to 0 rank keep the edge fog cause, thereby has improved the motion picture quality.
Invention disclosed provides a kind of structure in patent file 4, wherein is distributed with machinery or electronic shutter in optical path, and Shows Picture and carry out synchro switch along with one, so that the non-static part of excision display lamp.This structure has reduced owing to 0 rank keep the edge fog cause, thereby has improved the motion picture quality.
But, be used for to suppress to prevent that ill-defined each method from all can cause other problems that wherein display brightness and contrast descend because of inserting the black replacement because the above-mentioned black of the motion picture deterioration that the maintenance of 0 rank causes is reset by inserting.
Especially, according to the The Application of Technology of invention disclosed in above-mentioned patent file 1 and 2, reduced the brightness that shows when having high-high brightness white.
In above-mentioned patent file 3 in the invention disclosed, be in by illuminating state by all light sources that make luminaire, the decline of the display brightness when having suppressed to show rest image, but when showing motion picture, compare with the situation of not carrying out the black replacement, gray scale has descended, and erect image is such in the situation of the invention described in patent file 1 and 2.
Invention disclosed has only whole screen or the one-row pixels of using display device to be the unit in above-mentioned patent file 4, can carry out black and reset.As a result, when showing motion picture, the pixel that does not need to carry out the black replacement is carried out the black replacement, therefore reduced display brightness.
Like this, therefore under the situation that does not reduce high-high brightness and contrast, can not improve the motion picture quality.
Summary of the invention
Above-mentioned situation has been considered in proposition of the present invention.Target of the present invention is to propose a kind of image processing method, be used to drive the method for display device, and, be used under the situation that does not reduce high-high brightness and contrast, improving the motion picture quality of maintenance display device by the display device that this method drives.
In order to realize above-mentioned target, as the first embodiment of the present invention, proposed the image processing method that a kind of wherein vision signal in a frame period is time-divided into a plurality of subframes, and at least a portion of the luminance component of the vision signal of predetermined subframe is assigned to the vision signal of undersaturated other subframes of luminance component.
In first embodiment, vision signal is the gray-scale signal of expression display element output level, and under the preferable case gray-scale value of the vision signal of subframe is distributed to the vision signal of other subframes.In addition, under the preferable case before the distribution of luminance component and do not change the overall brightness in a frame period afterwards.
In any image processing method of above-mentioned first embodiment, for any vision signal, under the preferable case at least a portion of the luminance component of the vision signal of predetermined subframe is distributed to the vision signal of undersaturated other subframes of luminance component with a plurality of color components that form color video.
In order to realize above-mentioned target, as the second embodiment of the present invention, a kind of driving and control method of maintenance display device have been proposed, wherein its brightness shows a predetermined period corresponding to the light of incoming video signal by display element, the vision signal that it is characterized in that a frame period is time-divided into a plurality of subframes, at least a portion of the luminance component of the vision signal of predetermined subframe is assigned to the vision signal of undersaturated other subframes of luminance component, and its feature is that also its brightness shows by display element in each period of sub-frame corresponding to the light of the vision signal of each subframe that has been assigned with luminance component.
In above-mentioned second embodiment according to the present invention, vision signal is the gray-scale signal of expression display element output level under the preferable case, and the gray-scale value of the vision signal of predetermined subframe is assigned to the vision signal of other frames.Under the preferable case before the distribution of luminance component and also do not change the overall brightness in a frame period afterwards.
In any driving and control method according to the maintenance display device of above-mentioned second embodiment, the colour-video signal that vision signal is made up of a plurality of color components under the preferable case, and for each color component, at least a portion of the luminance component of the vision signal of predetermined subframe is assigned to the vision signal of undersaturated other subframes of luminance component, and allocation proportion is the same with the ratio of the color component with maximum overall brightness.
In order to realize above-mentioned target, as the third embodiment of the present invention, a kind of display device has been proposed, comprising: image processing apparatus, be used for after the vision signal of being imported is carried out Flame Image Process, the vision signal of being imported being exported as gray-scale signal; And display device, be used for to Show Picture corresponding to brightness from the gray-scale signal of image processing apparatus output, wherein image processing apparatus comprises: the device that is divided into a plurality of subframes when being used for the vision signal with a frame period; Be used to specify the device of each time-division subframe sequence number, this sequence number is assigned to each subframe in the frame; And the grey level transition device, be used to each subframe to generate gray-scale signal, so that at least a portion of the luminance component of the vision signal of predetermined subframe is distributed to the vision signal of undersaturated other subframes of luminance component.
In above-mentioned the 3rd embodiment according to the present invention, the grey level transition device is by carrying out the four fundamental rules fundamental operation or with reference to look-up table under the preferable case, at least a portion of the luminance component of the vision signal of predetermined subframe distributed to the vision signal of undersaturated other subframes of luminance component.
In order to realize above-mentioned target, as the fourth embodiment of the present invention, a kind of display device has been proposed, comprising: the gray-scale voltage generating apparatus is used for generating the gray-scale voltage signal according to the vision signal of input, and is used for the output gray level magnitude voltage signals; And display device, being used for Showing Picture with brightness corresponding to the gray-scale voltage signal, this display device further comprises: the device that is divided into a plurality of subframes when being used for a frame video signal; Be used to specify the device of each time-division subframe sequence number, this sequence number is assigned to each subframe in the frame; And the device that is used to change reference voltage, the gray-scale voltage generating apparatus generates the gray-scale voltage signal according to reference voltage, so that at least a portion of the luminance component of the vision signal of predetermined subframe is distributed to the vision signal of undersaturated other subframes of luminance component.
In above-mentioned third and fourth embodiment according to the present invention, the colour-video signal that vision signal is made up of a plurality of color components under the preferable case, and for each color component, at least a portion of the luminance component of the vision signal of predetermined subframe is distributed to the vision signal of undersaturated other subframes of luminance component, and allocation proportion is the same with the ratio of the color component with maximum overall brightness.Under the preferable case before the distribution of luminance component and do not change the overall brightness in a frame period afterwards.
In order to realize above-mentioned target, as the fifth embodiment of the present invention, a kind of display device has been proposed, comprising: image processing apparatus, be used for after the vision signal of being imported is carried out Flame Image Process, the vision signal of being imported being exported as gray-scale signal; And display device, be used for Showing Picture with brightness corresponding to the gray-scale signal of exporting from image processing apparatus, wherein image processing apparatus is according to above-mentioned first embodiment of the present invention, to the vision signal carries out image processing method of being imported.
In order to realize above-mentioned target, as the sixth embodiment of the present invention, a kind of display device has been proposed, wherein the driving method according to the maintenance display device of above-mentioned second embodiment of the present invention Shows Picture.
According to the present invention, can propose a kind of image processing method, be used to drive the method for display device, and by display device that this method drove, be used under the situation that does not reduce high-high brightness and contrast, improve the motion picture quality in the maintenance display device.
Description of drawings
Come to tell about in detail the preferred embodiments of the present invention below with reference to the accompanying drawings, wherein:
Fig. 1 shows principle of the present invention;
Fig. 2 shows the structure according to the liquid crystal display that is used to carry out the first embodiment of the present invention under the preferable case;
Fig. 3 shows the structure according to the image processing section of the liquid crystal display of first embodiment;
Fig. 4 is according to the processing time sequential routine figure in the Digital Image Processing part of the liquid crystal display of first embodiment;
Fig. 5 shows to according to the amplification factor of carrying out the liquid crystal display of the first embodiment of the present invention in the preferred case the LUT example that part provides being set;
Fig. 6 shows to the amplification factor according to the liquid crystal display of first embodiment LUT example that part provides is set;
Fig. 7 is according to the processing time sequential routine figure in the Digital Image Processing part of the liquid crystal display of first embodiment;
Fig. 8 shows corresponding to changing from the pixel intensity according to the signal of the image processing part branch the liquid crystal display of first embodiment output;
Fig. 9 shows the structure according to the image processing section of the liquid crystal display that is used to carry out the second embodiment of the present invention under the preferable case;
The LUT example that is provided for the grey level transition part according to the liquid crystal display of second embodiment is provided Figure 10;
Figure 11 shows the structure according to the image processing section of the liquid crystal display that is used to carry out the third embodiment of the present invention under the preferable case;
Figure 12 shows to the amplification factor according to the liquid crystal display of the 3rd embodiment the LUT example that part provides is set;
Figure 13 shows the structure according to the Digital Image Processing part of the liquid crystal display that is used to carry out the fourth embodiment of the present invention under the preferable case;
Figure 14 shows the structure according to the liquid crystal display that is used to carry out the fifth embodiment of the present invention under the preferable case;
Figure 15 shows the structure according to the image processing section of the liquid crystal display of the 5th embodiment;
Figure 16 shows the process that partly produces output signal according to the frame rate conversion of the liquid crystal display of the 5th embodiment;
Figure 17 shows the process that partly produces output signal according to the Digital Image Processing of the liquid crystal display of the 5th embodiment;
Figure 18 is the processing time sequential routine figure according to the Digital Image Processing part of the liquid crystal display that is used for carrying out the sixth embodiment of the present invention under the preferable case;
Figure 19 shows to the amplification factor according to the liquid crystal display of the 6th embodiment the LUT example that part provides is set;
Figure 20 shows corresponding to changing from the pixel intensity according to the signal of the image processing part branch the liquid crystal display of the 6th embodiment output;
Figure 21 shows the structure according to the liquid crystal display that is used to carry out the seventh embodiment of the present invention under the preferable case;
Figure 22 shows the structure according to the image processing section of the liquid crystal display of the 7th embodiment;
Figure 23 shows the I/O characteristic according to the D/A converter of the liquid crystal display of the 7th embodiment;
Figure 24 shows the structure of reference gray level step voltage generating portion;
Figure 25 shows another exemplary construction according to the image processing section of the liquid crystal display of the 7th embodiment;
Figure 26 shows the structure according to the image processing section of the liquid crystal display that is used to carry out the eighth embodiment of the present invention under the preferable case;
Figure 27 is a figure, is used for explaining the processing of overdriving, and wherein A shows the input gray grade value, and B shows transmissivity;
Another exemplary construction of the LUT that is provided for the grey level transition part according to the liquid crystal display of the 8th embodiment is provided Figure 28; And
Figure 29 is a figure, is used for explaining the processing of overdriving, and wherein A shows the response wave shape in the existing driving method, and B shows the response wave shape when processing is overdrived in execution.
Embodiment
(inventive principle)
Be input to digital video signal, sent by speed with per second f frame such as maintenance display devices such as liquid crystal displays.F is called frame per second.In shared maintenance display device, frame per second equals driving frequency (the maintenance display device is used to rewrite the operating frequency of screen display).
But, in the present invention, set driving frequency is higher than frame per second.N times of this situation that hereinafter with the driving frequency is frame per second is example, explains principle of the present invention.In this case, a frame (frame period) is divided into n subframe (drive cycle).That is to say that in the present invention in order to rewrite picture in period of sub-frame, driving frequency is n doubly (n * f), and the drive cycle (n * f) that is 1/ of frame per second.
Except driving frequency was higher than frame per second, the structure of describing among the application was identical with the structure of existing maintenance display device, unless need specialize.That is to say that the present invention is mainly the mode of aim target each in gray level being distributed to n time-division subframe.
Fig. 1 shows the mode of gray level being distributed to each subframe of forming a frame.Here, taking the situation of n=3 is example.The transverse axis express time, and the longitudinal axis is represented the brightness of each RGB component.Below, explain the method for luminance component being distributed to each subframe of a frame with reference to figure 1.
Gray level three subframes is under the independent controlled situation, very many combinations can occur on gray level expression method.For example, be defined as 1 brightness transition in the brightness according to white, (under situation B)=(0.6,0.5,0.2), any one output valve can be set to (0.6,0.5,0.2) (thick line among Fig. 1) to the input signal values of pixel in three subframes for R, G.In this case, be presented at maintenance display device the same that motion picture and driving frequency on the screen equals frame per second, therefore can not improve moving image quality.
Alternatively, each output valve first and second subframes is set to (0.6,0.5,0.2) and do not consider input signal values and carry out so-called " black reset drive ", the output valve of the 3rd subframe is set to (0,0,0) under the situation, reduced the deterioration that shows the motion picture quality that is caused by maintenance.But, owing in the 3rd frame that shows with brightness at first, carried out black display corresponding to input signal values, so the brightness of entire frame descends.
Any one luminance component of n subframe can be assigned to (in above-mentioned example, the luminance component of the 3rd subframe is assigned to first and second subframes) in other frames according to maintenance display device of the present invention.For example, subframe value by first and second subframes is set to (0.9,0.75,0.3) and the subframe value of the 3rd subframe be set to (0,0,0), then the overall brightness on a whole frame will keep constant, and can reduce the deterioration of motion picture quality, can not make brightness decline (Fig. 1: thick point-like outline line) simultaneously.
On the other hand, when input signal values during, then all luminance components of any subframe can't be distributed to other subframes greater than (n-1)/n.For example, under the situation of n=3, when input signal values greater than 2/3 the time, all luminance components of the 3rd subframe can not be assigned to other frames.In this case, can improve the motion picture quality by any one luminance component of these subframes is distributed to other subframes as much as possible.
Because any one luminance component of these subframes can not be assigned to other subframes (because the luminance component of all subframes is a maximal value) that are in white and show, therefore can't carry out Luminance Distribution.
In the natural picture that does not include the pixel that has high brightness in a large number, (luminance component of any subframe can not be assigned to other subframes), can improve the motion picture quality of motion picture, even include at motion picture under the situation of this pixel and also be fine.
Although along with the brightness of whole screen display increases, flicker trends towards obviously, according to the present invention, has rewritten screen display for being in each subframe that has an equal state with the situation that refresh rate is adjusted to n times, thus the generation that can suppress to glimmer.
By using this structure, can suppress the decline of high-high brightness, and can improve the motion picture quality.
In the method that is used for gray level is distributed to n subframe, make that the number of the subframe that luminance component is relatively concentrated is the least possible, perhaps the source of luminance component is fixed.That is to say that during handling, the number with subframe of minimum luminance component remains unchanged under the preferable case.
Be used to distribute the concrete grammar of gray level to comprise a kind of being used for by incoming video signal being multiply by the method for the amplification coefficient that obtains according to each subframe numbers, and a kind of being used for by using look-up table to carry out the method for grey level transition.Under the situation of liquid crystal display, can also realize this method by such structure, wherein in this structure, change the reference gray level step voltage that is used for the digital grayscale conversion of signals is become to be used for the D/A converter of the aanalogvoltage that writes at liquid crystal.Concrete method is not limited to said method, and can use other can obtain result's technology according to above-mentioned distribution method.
From needing not to be consistent to quantity allotted as the subframe of distributing target as the subframe of distributing the source.For example, under the situation of n=3, even the amount that is assigned to first subframe increase under the situation more than the amount that is assigned to second subframe, also can improve the motion picture quality.In addition, any subframe can be used to distribute luminance component as the distribution source.That is to say that this distribution is not limited to from the situation of the 3rd subframe to the first and second subframe, and can carry out from the distribution of first subframe to the second and the 3rd subframe, and from the distribution of second subframe to the first and the 3rd subframe.But, all continuous motion pictures need use the fixing subframe with same numeral as the distribution source to handle.
Explain below according to the preferred embodiments of the present invention based on above-mentioned principle.
(first embodiment)
Structure of the present invention
Tell about below and be used for carrying out in the preferred case the first embodiment of the present invention.Fig. 2 shows the structure according to the liquid crystal display of present embodiment.This liquid crystal display comprises image processing section 11 and liquid-crystal display section 12.Image processing section 11 comprises memory portion 21, is used to store the picture signal of being imported, and Digital Image Processing part 22, is used for the picture signal of being imported is carried out arithmetical operation.
Liquid-crystal display section 12 comprises scan line driver 33, signal line drive 34 and picture element matrix part 38.Picture element matrix part 38 comprises a plurality of sweep traces 31, a plurality of signal wire 32, a plurality of pixel 35, auxiliary capacitor 36 and thin film transistor (TFT) (TFT) 37.A plurality of sweep traces 31 and a plurality of signal wire 32 intersect.Each intersection at sweep trace 31 and sweep trace 32 is connected with pixel 35 via TFT 37.Auxiliary capacitor 36 is in parallel with each pixel 35, so that suppress to cause owing to the characteristics fluctuation of pixel 35 variation of display gray scale.
Scan line driver 33 controls are input to the signal of a plurality of sweep traces 31.Signal line drive 34 is being controlled the signal that is input to a plurality of signal wires 32.
Here, explained from working as digital signal input (control signal CLK (Hsync, Vsync, data enable (DE))+digital video signal (R, G, B)) when being input to image processing section 11, to this processing procedure that picture ought be presented in the liquid-crystal display section 12.The digital signal of 11 pairs of inputs of image processing section is carried out arithmetical operation, and controls according to the control signal of being imported, and output digital video signal and control signal are given liquid crystal display part 12.
The digital video signal and the control signal that output to liquid-crystal display section 12 from image processing section 11 are assigned to scan line driver 33 and signal line drive 34 respectively.Signal line drive 34 is according to the voltage-light characteristic of imposing on pixel 35, and from the gamma characteristic of the vision signal imported and the conversion characteristic that obtains converts digital video signal to analog voltage signal (D/A conversion).
Signal line drive 34 imposes on the pixel 35 that is connected to sweep trace 31 via the signal that TFT37 will be converted into aanalogvoltage, wherein scan line driver 33 applies the ON of-state voltage according to digital video signal and control signal from image processing section 11 inputs selectively to sweep trace 31.The voltage that signal line drive 34 imposes on pixel 35 is converted into light via pixel 35, so that show as image.
Fig. 3 shows the detailed structure of image processing section 11.Digital Image Processing part 22 comprises: counter and control signal generating portion 44 are used for controlling according to the control signal of being imported the timing of output control signal, and are used to generate Counter Value; Amplification factor is provided with part 42, is used for according to the vision signal sum counter value of being imported amplification factor being set; Buffer memory 43 is used for by the processing time delayed video signal of part 42 is set in amplification factor; And Arithmetic Section 41, be used for the amplification factor that part 42 is provided with being set and come vision signal is carried out arithmetical operation according to amplification factor.Be imported into digital video signal in the Digital Image Processing part 22 via the FIFO (not shown) from memory portion 21 input and output.Vision signal to and writing and reading according to the storer control signal and carry out from memory portion 21.
(invention operation)
Next, tell about operation according to the liquid crystal display of present embodiment.
Fig. 4 shows and sequential chart from each signal of Digital Image Processing part 22 input and output.One frame is being divided under the situation of n subframe, the vertical synchronizing signal Vsync that n pulse arranged in a frame period is from counter and 44 outputs of control signal generating portion.Counter Value is the value that shows the subframe sequence number that is included in the frame, and rises at Vsync that point is counted device and control signal generating portion 44 changes.By a frame being divided into n subframe, from the output signal of memory portion 21 and such as Hsync and DE etc. the output of signal synchronously regularly also be changed into the n of frame per second doubly.The timing of these control signals is provided with by counter and control signal generating portion 44, among the erect image Vsync like that.
In Fig. 3, be input in the control signal of counter and control signal generating portion 44, vertical synchronizing signal Vsync is modulated in counter and control signal generating portion 44 after n times in its frequency, and a part that is used as the output control signal sends to liquid-crystal display section 12.Other control signals are after counter and control signal generating portion 44 are carried out frequency inverted, and a part that is used as the output control signal sends to liquid-crystal display section 12, among the erect image vertical synchronizing signal Vsync like that.
In counter and control signal generating portion 44, also generated the storer control signal, so that regularly, control view data to/writing and reading from memory portion 21 according to the generation of synchronizing signal.
The n system counter of the output that is used to count vertical synchronizing signal is provided in counter and control signal generating portion 44.The count value of counter is the value that shows the subframe sequence number in the frame, and is sent to amplification factor part 42 is set.
Be sent to amplification factor from the digital video signal of memory portion 21 output part 42 and buffer memory 43 are set.In buffer memory 43, for that the result of part 42 is set is synchronous with amplification factor, output has been delayed the schedule time (being used to calculate the time of amplification factor a).
Be provided with in the part 42 in amplification factor, exported the amplification factor that the rgb value sum counter value according to input signal obtains.For each color component that distributes similarly,, need to use identical amplification factor for any one color component of RGB.For this reason, amplification factor is provided with part 42 and extracts the color component with maximum brightness value from each color component of RGB, and determines amplification factor with reference to the look-up table (LUT) 421 based on the brightness value sum counter value of color component.
Fig. 5 shows the structure that the LUT421 that part 42 stores is set by the amplification factor in the present embodiment.Here, suppose gamma correction γ=2.2 that input signal values is suffered.Suppose that the maximum gray scale extreme value that shows corresponding to white is 255 gray levels (8 bits).Because a frame is divided into n subframe, therefore when the high-high brightness in hypothesis one frame is 1, can be positioned at the scope of 0~1/n by the brightness that a subframe is represented.
Maximal value at each color component of RGB is not more than int (255 * (1/n) 1/2.2) under the situation of individual gray level, (wherein int (x) expression is to the x round numbers), maybe when converting brightness under the situation less than 1/n, amplification factor is provided with part 42 and determines amplification factor a, makes all luminance components be assigned to first subframe.
Maximal value at each color component of RGB is not less than int (255 * (1/n) 1/2.2)+1 gray level, and be not more than int (255 * (2/n) 1/2.2) situation under (if convert to brightness value then is not less than 1/n and less than 2/n), amplification factor is provided with part 42 and determines amplification factor a, makes all luminance components be assigned to first and second subframes.
Under the optional situation, when the maximal value of each color component of RGB is not less than int (255 * (n-1/n) 1/2.2(if converting brightness value to then is not less than (n-1)/n), amplification factor is provided with part 42 and determines amplification factor a, makes all luminance components be assigned with, so that make the luminance component of leaving n subframe for as far as possible little during)+1 gray level.
Arithmetic Section 41 will be provided with each RGB color component that part 42 determined amplification factor a multiply by incoming video signal by amplification factor, and (aR, aG aB) export to liquid crystal display 12 as digital video signal with the factor as a result.
In a frame period, owing in Arithmetic Section 41, carry out before the arithmetical operation and afterwards (in other words, between digital video input signal and digital video output signal) overall brightness can not change, therefore high-high brightness and contrast do not reduce, and realized the false pulse demonstration, as a result, improved the motion picture quality.
Here, suppose when determining above-mentioned amplification factor a, for each color component of RGB has used identical value.This is because under the situation that the luminance component ratio is different in subframe, has generated false colour (colors different with the color of desired display) when showing motion picture.But, even the amplification factor difference of each color component of RGB also can obtain to improve the effect of motion picture quality.
Like this, by luminance component is concentrated on a part of subframe, and do not consider the separated number n of a frame, then improved the motion picture quality, can not reduce brightness simultaneously.Use bigger n value, can carry out the demonstration of 0 brightness value more easily, just black display.As a result, can obtain to improve the remarkable result of motion picture quality.
Be that example is told about the operation according to the liquid crystal display of present embodiment in detail below with n=3.
Fig. 6 shows the value of the LUT when the gamma correction γ that is subjected to of hypothesis input signal values=2.2.Here, suppose that the maximum gray scale value that shows corresponding to white is 255 gray levels (8 bits).
Be no more than at the most at the gray-scale value of each color component of RGB under the situation of 154 gray levels (if convert brightness to, then less than 1/3), amplification factor is provided with part 42 and determines amplification factor a, makes all luminance components be assigned to first subframe.
The maximal value of the gray-scale value of each color component of RGB be not less than 155 and be not more than under the situation of 212 gray levels (if convert to brightness value then be not less than 1/3 and less than 2/3), amplification factor is provided with part 42 and determines amplification factor a, makes the luminance component of the 3rd subframe be assigned to first and second subframes.
Be not less than in the maximal value of the gray-scale value of each color component of RGB under the situation of 213 gray levels (if convert brightness to, then be not less than 2/3), amplification factor is provided with part 42 and determines amplification factor a, make the luminance component of the 3rd subframe be assigned to first and second subframes, so that make the luminance component of leaving the 3rd subframe for as far as possible little.
Arithmetic Section 41 will be provided with each RGB color component that amplification factor a that part 42 determines multiply by received image signal by amplification factor, and (aR, aG aB) export to liquid crystal display 12 as digital video signal with the factor as a result.
In a frame period, owing in Arithmetic Section 41, carry out before the arithmetical operation and afterwards (in other words, between digital video input signal and the digital video output signal) overall brightness do not change, therefore high-high brightness and contrast do not reduce, and realized the false pulse demonstration, as a result, improved the motion picture quality.
Here, suppose when amplification factor is provided with part 42 and determines above-mentioned amplification factor a, for each color component of RGB has used identical value.This is because under the different situation of brightness ratio between the subframe, has generated false colour (colors different with the color of desired display) when showing motion picture.But, even the amplification factor difference of each color component of RGB also can obtain to improve the effect of motion picture quality.
Input gray grade shown in Figure 7 is the output signal from memory portion 21, and output gray level is the output from Arithmetic Section 41.Counter Value is to send to the signal that amplification factor is provided with part 42 from counter and control signal generating portion 44, and amplification factor a is that amplification factor is provided with the signal that part 42 outputs to Arithmetic Section 41.Counter Value obtains counting at the rising point of Vsync output, and shows the subframe sequence number in the frame.
As shown in the figure, at hypothesis every frame 3 times the RGB gray-scale signal is input under the situation of memory portion 21, wherein the gray-scale value of each color component is set to (R, G, B)=(210,150,72), the maximum gray scale value of input signal is 210 in this case.
Amplification factor a is provided with part 42 bases LUT 421 as shown in Figure 6 by amplification factor to determine that the result determines a=1.214 for first subframe, is that second subframe determined a=1.191, and is that the 3rd subframe determined a=0.
For each color component of RGB, be used for determining that the input gray grade value (digital video signal) of amplification factor a also is imported into buffer memory 43 from memory portion 21.Be set to amplification factor the time delay of buffer memory 43 time that part 42 is used for determining amplification factor a is set, and postponed the input gray grade value of the schedule time and be output to Arithmetic Section 41.
Arithmetic Section 41 for each color component of RGB is carried out arithmetical operation, and with the part that the output gray level value that obtains is exported as digital video, is exported to liquid-crystal display section 12 according to the amplification factor a of each subframe.
Fig. 8 shows will being worth corresponding voltage with the output gray level of using above-mentioned amplification factor a to calculate by scan line driver 33 and signal line drive 34 and is applied on the pixel 35 in this case time-light characteristic.
Vision signal γ=2.2 are imported and to before in Arithmetic Section 41, carrying out arithmetical operation and under the situation about comparing of R luminance component afterwards in hypothesis, as can be seen before handling, (210/255) 2.2=0.652, and after handling, 1/3 * (255/255) 2.2+ 1/3 * (250/255) 2.2=0.652, show before the processing of Arithmetic Section 41 and afterwards, overall brightness does not change.In addition, amplification factor is that 0 the 3rd subframe belongs to black display, therefore can improve the motion picture quality.
Like this, the motion picture quality can be improved, brightness can be do not reduced simultaneously according to the liquid crystal display of present embodiment.
Although told about several examples here, wherein under the situation of brightness transition, 1/3 and 2/3 value is used as the scope lower limit, being used for determining amplification factor, can obtain same effect in these values of use under as the situation of range limit.
(second embodiment)
Tell about below and be used for carrying out in the preferred case the second embodiment of the present invention.With the same according to the liquid crystal display of first embodiment, comprise image processing section 11 and liquid-crystal display section 12 according to the liquid crystal display of present embodiment.
Fig. 9 shows the structure according to the image processing section 11 of the liquid crystal display of present embodiment.In the present embodiment, Digital Image Processing part 22A does not comprise Arithmetic Section 41 and buffer memory 43, and comprises grey level transition part 45.
In the present embodiment, be imported into grey level transition part 45 from the count value of counter and 44 outputs of control signal generating portion and the digital video signal of exporting from memory portion 21 (gray-scale value of input).
In grey level transition part 45, with reference to the LUT 451 based on the input gray grade value and the count value of digital video signal as shown in figure 10, and the part that corresponding value is exported as digital video signal is output to liquid-crystal display section 12.LUT as shown in figure 10 just is divided into the situation of three subframes corresponding to the situation of n=3 when with a frame.
In the present embodiment,, therefore compare, can reduce the circuit scale of image processing section 11 with first embodiment owing in image processing section 11, there is not amplifier (Arithmetic Section 41).
In said structure, improved the motion picture quality, do not reduce brightness simultaneously, therefore reduced edge fog.
In the present embodiment, because gray-scale value according to each color component, with reference to LUT, and do not extract color component with maximum gray scale value from each color component of RGB, therefore can't be as according to according to the liquid crystal display of first embodiment, reaching the effect that prevents false color.But, owing in liquid crystal display, in white and black display, do not have false color, therefore can obtain and motion picture quality same in liquid crystal display according to first embodiment according to present embodiment.
Like this, can improve the motion picture quality, and its structure is wanted beguine simple according to the liquid crystal display of first embodiment, can not reduce brightness simultaneously according to the liquid crystal display of present embodiment.
(the 3rd embodiment)
Be input as at digital video signal under the situation of 8 bits, above-mentioned first and second embodiment can make the LUT that is quoted when conversion gray level or definite amplification factor that is provided have record corresponding to 256 gray levels (that is to say to have same number with the gray level of digital video signal input).
But, in this structure, be provided with in part 42 or the grey level transition part 45, need 256 * (the required bit number of LUT that is used for a gray level) so big memory spans for LUT 421 and 451 being stored in amplification factor.Therefore, in the present embodiment, told about the structure that is used to reduce to be used to store the memory span of LUT.
The same with in first embodiment, liquid crystal display according to the present invention comprises image processing section 11 and liquid-crystal display section 12.
Figure 11 shows the structure according to the image processing section 11 of the liquid crystal display of present embodiment.In the present embodiment, image processing section 11 the same with according to the liquid crystal display of first embodiment, and comprise memory portion 21 and Digital Image Processing part 22B.But, in this embodiment, by the amplification factor of Digital Image Processing part 22B LUT 421A that part 42A stored being set numerically is different from by the amplification factor according to the Digital Image Processing part 22 of the liquid crystal display of first embodiment included LUT 421 of part 42 is set.Although told about here have with liquid crystal display according to first embodiment in the structure of the same Digital Image Processing part, this structure can comprise and Digital Image Processing part the same in the liquid crystal display according to second embodiment.In this case, LUT is stored in the grey level transition part 45.
The amplification factor that Figure 12 shows by present embodiment is provided with the LUT421A that part 42A is stored.LUT is corresponding to n=3, just is divided into the situation that three subframes are carried out processing by with a frame time.In LUT 421A, these records are made of three gray level region, and comprising the zone of 0~154 gray level, wherein maximum gray scale is less than 1/3 of white; The zone of 155~212 gray levels, wherein maximum gray scale be not less than white 1/3 and less than 2/3 of white; And the zone of 213~255 gray levels, wherein maximum gray scale be not less than white 2/3, and in each gray level region reference be identical value.These are worth with identical corresponding to the value of the maximum gray scale value in each gray level region among the LUT 421 among first embodiment as shown in Figure 7, just 154 gray levels, 212 gray levels and 255 gray levels.
Although by data volume according to the employed LUT 421A of the liquid crystal display of present embodiment, with compare extremely for a short time with 451 data volume according to the employed LUT 421 of the liquid crystal display of first and second embodiment, even when using LUT 421A, under above the situation that does not have result of calculation in the Arithmetic Section 41 of 255 gray levels, also can distribute luminance component.
Like this, the liquid crystal display of present embodiment can improve the motion picture quality under the situation that does not reduce brightness, and and then can be reduced to less than the memory span according to the liquid crystal display of first and second embodiment with carrying out to handle to improve the required memory span (being used to store the memory span of LUT) of motion picture quality.
(the 4th embodiment)
Tell about below and be used for carrying out in the preferred case the fourth embodiment of the present invention.Liquid crystal display according to present embodiment comprises image processing section 11 and liquid-crystal display section 12, in first embodiment.
The structure of the image processing section 11 that provides for the liquid crystal display according to present embodiment is provided Figure 13.Although the image processing section 11 that provides for the liquid crystal display according to present embodiment is the same with as shown in Figure 3 first embodiment almost, the structure of Digital Image Processing part 22 is different.Digital Image Processing part 22 in the present embodiment includes additive value part 50 is set, rather than amplification factor is provided with part 42.
Additive value is provided with part 50 according to each the color component R from memory portion 21 inputs, G, B, and from the count value of counter and 44 inputs of control signal generating portion, output all different additive value aR, aG and aB for each color component.
Additive value is provided with part 50 and extracts the color component with maximum gray scale value from each color component of RGB, and determines additive value with reference to the LUT501 based on the count value of gray-scale value and color component.Therefore, the ratio of the additive value of each color component is identical with the amplitude proportional of the gray-scale value of each color of importing from memory portion 21.
Although carrying out, Arithmetic Section 41 is used for multiply by respectively from the amplification factor a that amplification factor is provided with part 42 outputs from the processing of the gray-scale value of each color of buffer memory 43 outputs at first embodiment, but in the present embodiment, Arithmetic Section 41 is carried out and is used for and will the additive value and processing from the gray-scale value addition of each color component of buffer memory 43 outputs of each color component of part 50 outputs be set from additive value.
Because the same among other structures and operation and first embodiment, so ignored the explanation of repetition.
In the present embodiment, in a frame period, owing in Arithmetic Section 41, carry out before the arithmetical operation and afterwards (in other words, between digital video input signal and digital video output signal) not change of overall brightness, therefore high-high brightness and contrast do not descend, and having realized the false pulse demonstration, the result has improved the motion picture quality.
(the 5th embodiment)
In above-mentioned first to fourth embodiment, told about the situation that a frame is time-divided into any n frame (n is any natural number), in other words, promptly the driving frequency of liquid crystal display is the situation of the natural multiple of video frequencies.But, because the present invention is applicable to that driving frequency is not the situation of natural multiple, in the 5th embodiment, explained that driving frequency is that f2 and picture frequency are the f1 (situations of f2>f1).
Figure 14 shows the liquid crystal display according to present embodiment.This liquid crystal display comprises image processing section 11A and liquid-crystal display section 12, as in the liquid crystal display according to first embodiment.But, in the present embodiment, image processing section 11A includes the frame rate conversion part 23 in the previous stage of Digital Image Processing part 22D.
The frame per second of the vision signal that frame rate conversion part 23 conversion is imported, and will be converted signal and output to Digital Image Processing part 22D.
Next, told about the structure of Digital Image Processing part 22D.Figure 15 shows the structure of the image processing section 11A among this embodiment.Digital Image Processing part 22D comprises that Arithmetic Section 41, amplification factor are provided with part 42, buffer memory 43 sum counters and control signal generating portion 44, the same with among first embodiment.But, in the present embodiment, control signal and digital video signal input are not by memory portion 21 outputs, but by 23 outputs of frame rate conversion part, and be imported into Digital Image Processing part 22D.In the present embodiment, write information to memory portion 21 and therefrom read message be not the control that is subjected to counter and control signal generating portion 44, but be subjected to the control of frame rate conversion part 23.
Explain the operation of frame per second conversion portion 23 and Digital Image Processing part 22D below with reference to Figure 16 and 17.
Figure 16 is a figure, shows the vision signal that is input to frame rate conversion part 23 under the condition of f2=2.5 * f1, and the vision signal that outputs to Digital Image Processing part 22D from frame rate conversion part 23.The transverse axis express time, and frame picture F is changing at any time.The top of figure shows the time series of the frame picture of input end vision signal, and the frame picture change into F1, F2, F3 ....On the other hand, the time series of the frame picture of output terminal vision signal is represented in the bottom of this figure, and the frame picture change into F1 ', F2 ', F3 ' ....The frame picture F1 of input and the frame picture F1 ' of output are the images of synchronization.
In shared frame rate conversion, need be at each 1/f2 cycle output frame picture F ' as the output cycle.On the other hand, in liquid crystal display,, just each n/f2 cycle, exported frame picture F ' in each cycle as output cycle integral multiple according to present embodiment.
In example as shown in figure 16, for each 2/f2 has generated frame picture F ', and for the frame picture that does not wherein have delta frame picture F ', the image of former frame is used as former state output.At this moment, be F1 ', F1 ', F2 ', F2 ' from the time series of the two field picture of frame rate conversion part 23 output, F3 ', F3 ' ..., make and in a plurality of frames, exported same width of cloth image.In other words, image transitions has the same meaning with the frame rate conversion of carrying out f ' 2=1.25 * f1.But, piece image was repeatedly exported in the cycle of f ' 2.
Although in frame rate conversion, the arithmetical operation of conversion process becomes complicated along with the increase of conversion amplification factor, and in the present embodiment, the conversion amplification factor is suppressed smallerly, and therefore the conversion amplification factor in frame rate conversion can be smaller.
Figure 17 is a figure, shows vision signal that is input to digital video signal processing part 22D and the vision signal of exporting from Digital Image Processing part 22D.The transverse axis express time, and frame picture F changes at any time.Shown in the top of figure, and the sequential of the frame picture of output terminal vision signal is shown in the bottom of figure in the sequential of the frame picture of input end vision signal.
Here the processing of Zhi Hanging is the same with the processing described in first embodiment.That is to say, in an example shown, because successively the same image of two frames is imported among the Digital Image Processing part 22D, so Digital Image Processing part 22D is considered as first subframe with 2/f2, and 1/f2 is considered as second subframe, distributes so that carry out gray level.As a result, the luminance component of second subframe is distributed to first subframe as much as possible, so that obtain as F " 1, F " ' 1, F " 2, F " ' 2, F " 3, F " ' 3 ... the sequential of output frame.
As mentioned above, in driving frequency is that f2 and video frequencies are that f1 is (under the situation of f2>f1), in frame rate conversion part 23, carried out f2/nf1 frequency inverted doubly, and a frame is divided into n subframe when being considered to, so that in Digital Image Processing part 22D, it is carried out the gray level distribution.Even, also can under the situation that does not reduce brightness, improve the motion picture quality therefore, in the cutting apart under the situation that number is a positive count an of frame.
Like this, just can obtain effect of the present invention, suppose that driving frequency is higher than video frequencies, and a frame can be time-divided into a subframe arbitrarily.
(the 6th embodiment)
Above-mentioned first to the 5th embodiment tells about under the identical situation of each period of sub-frame of forming a frame.But, (in other words the present invention can be applied to form each period of sub-frame of frame situation inequality, ground was not divided into the subframe with identical time cycle when promptly a frame was waited), the 6th embodiment tells about under each period of sub-frame of forming frame situation inequality.
The same according to the structure of the liquid crystal display of present embodiment and first embodiment.But, the computing frequency of counter and control signal generating portion 44 is different from the frequency in first embodiment, and by amplification factor the employed LUT 423 that are used for determining amplification factor a of part 42 is set and also is different from LUT 421 at first embodiment.
Figure 18 shows the sequential chart under the situation about Showing Picture in the pixel 35 according to the liquid-crystal display section in the liquid crystal display of present embodiment 12.Here, suppose that a frame is time-divided into two subframes, and the ratio of first period of sub-frame and second period of sub-frame is 2: 1 (first period of sub-frame is the twice of second period of sub-frame).
Be input to the digital video signal of image processing section 11 with video frequencies f, after in being stored in memory portion 21, be input to Digital Image Processing part 22 with the driving frequency (just three of video frequencies times) that is used for handling second subframe (subframe) with shorter time cycle temporarily.
At this moment, the vision signal of same image is imported into Digital Image Processing part 22 during two period of sub-frame, the same with in above-mentioned each embodiment.
Because the length of time cycle of first subframe is the twice of second subframe, so the digital video signal in first subframe finishes in the preceding half period of first subframe, and is therefore invalid in the back half period of first subframe.Digital Image Processing part 22 reading number vision signal from memory portion 21 not during periods of inactivity.
In the beginning of each subframe, Vsync is output with pulse mode.At this moment, during first period of sub-frame, the hold period that writes the gray-scale value of pixel 35 is the twice of second period of sub-frame.
Therefore, when the maximum gray scale value of any one color component of RGB is not more than 212 gray levels (if converting brightness to then less than 2/3), all luminance components of second subframe are assigned to first subframe.
When the maximum gray scale value of any one color component is not less than 213 gray levels (if convert brightness to then be not less than 2/3), the luminance distribution of execution makes that to stay second luminance component in the subframe as far as possible little.
Figure 19 shows amplification factor the structure of part 42 at the LUT 423 of the time institute's reference that distributes luminance component according to this rule is set.In the present embodiment, because a frame is divided into two subframes, so LUT is by forming less than the data volume under the situation that a frame is divided into three subframes.
Figure 20 shows the time-light characteristic that is written into the vision signal in the pixel 35, as carrying out the The results of data processing described in the present embodiment.Because the luminance component of second subframe is assigned to first subframe, therefore in second period of sub-frame, has carried out black display, and realized the false pulse demonstration.
Like this, even under the mutually different situation of length of time cycle of each subframe of forming a frame, also can improve the motion picture quality, and can not reduce brightness.
(the 7th embodiment)
In above-mentioned each embodiment, all be in the liquid crystal display of telling about by digital video signal being carried out arithmetic processing and grey level transition, under the situation that does not reduce brightness, having improved the motion picture quality.
In the present embodiment, the structure of telling about has improved the motion picture quality by the reference gray level step voltage of the D/A converter of change liquid crystal display under the situation that does not reduce brightness.
Figure 21 shows the structure according to the liquid crystal display of present embodiment.This liquid crystal display the same with according to the liquid crystal display of first embodiment is except it further comprises reference gray level level signal generating portion 13.
In the present embodiment, not only be sent to liquid-crystal display section 12 from the output of Digital Image Processing part 22E, and be sent to reference gray level level signal generating portion 13.Output from reference gray level level signal generating portion 13 is sent to the D/A converter 14 that is included among the signal line drive 34A.
Figure 22 shows the structure of digital signal processing part 22E, and the situation that is used for digital signal processing part 22E is connected to other funtion parts.Digital signal processing part 22E is identical with the digital signal processing part 22 of first embodiment, does not just comprise Arithmetic Section 41.In this enforcement, the amplification factor data that part 42B output is set from amplification factor are sent to reference gray level level signal generating portion 13.Output from buffer memory 43 also is sent to D/A converter 14.
In the present embodiment, the processing that the gray level that is used to improve the motion picture quality is distributed is carried out by D/A converter 14.Reference gray level level signal generating portion 13 is provided with the reference gray level step voltage according to the amplification factor data that part 42B input is set from amplification factor.
The reference gray level step voltage comprise output voltage V 1, V2 ..., Vn, they be when according to certain reference voltage with gray-scale value D1, D2 ..., obtain when Dn is input to D/A converter 14.In D/A converter 14 as shown in figure 23,, convert the digital signal of importing to voltage output according to the reference gray level step voltage that generates by reference gray level level signal generating portion 13.When input was different from the gray-scale value of reference gray level level value, D/A converter 14 was determined output voltage by interpolation method (interpolation).
For example, when the amplification factor data that part 42B output is set from amplification factor are 1.202 times, reference gray level level signal generating portion 13 is determined the reference gray level step voltages, so that will export corresponding to the output voltage of 1.202 times of brightness of the output brightness of input gray grade value.
In D/A converter 14,, will become aanalogvoltage from the conversion of signals of buffer memory 43 outputs, and send it to pixel 35 according to the reference gray level step voltage that changes.
In the present embodiment, because reference gray level level signal generating portion 13 changes the reference gray level step voltage according to the amplification factor data that part 42B output is set from amplification factor, then among first embodiment, carry out the identical gray-scale voltage that has under the situation of gray level distribution like that from D/A converter 14 outputs and Arithmetic Section 41.
Told about the processing that the picture amplitude is double (just brightness is double) below, as an object lesson of Flame Image Process.Although in above-mentioned each embodiment, the picture amplitude changes by combine digital Flame Image Process in digital signal processing part 22, but in the present embodiment, the reference voltage that produces makes that to receive the brightness of reference gray level level signal generating portion 13 input signals that are used for " brightness is doubled " signal double in that part 42B is set from amplification factor, so that it is outputed to D/A converter 14.Therefore, obtained to be used to make identical output under the situation of the double processing of the value of data image signal processing costs with execution.
Figure 24 shows the exemplary construction of the reference gray level level signal generating portion 13 in the present embodiment.Reference gray level level signal generating portion 13 comprises a plurality of D/A converters (DAC) 14 and digital signal generating portion 15.Digital signal generating portion 15 is according to being provided with the signal that part 42B sends out from amplification factor, will output to D/A converter 14 corresponding to the digital signal of the value of reference gray level step voltage V1~V9.D/A converter 14 is according to the signal that sends out from digital signal generating portion 15, and output is corresponding to the aanalogvoltage of the signal of importing from buffer memory 43.
By carrying out above-mentioned processing, D/A converter 14 can generate expectation reference gray level step voltage for any switching signal that part 42B output is set by amplification factor.
Here, amplification factor is provided with part 42B can obtain maximum gray scale for each pixel 35, and reference gray level level signal generating portion 13 uses Dot Clock (being used to send the clock of a pixel data) to change the reference gray level step voltage.
On the other hand, as shown in figure 25, send to the maximum gray scale value that maximum gray scale value that amplification factor is provided with part 42B is used as a frame full screen display by taking, also can make reference gray level level signal generating portion 13 1 frames one frame ground change the reference gray level step voltage.
Like this, impose on the reference voltage of pixel by change, rather than, just can improve the motion picture quality, can not reduce brightness simultaneously by vision signal is carried out digital processing.
(the 8th embodiment)
In above-mentioned each embodiment, the operation of telling about is under the short situation of the pixel response period ratio period of sub-frame that imposes on liquid crystal display.In the present embodiment, explanation is the response cycle situation longer than period of sub-frame of pixel.
Figure 26 shows the structure according to the liquid crystal display of present embodiment.Image forming apparatus comprises image processing section 11 and liquid-crystal display section 12, the same with in first embodiment.Although in the present embodiment, image processing section 11 is the same with second embodiment almost, and Digital Image Processing part 22F comprises the part 46 of overdriving, rather than grey level transition part 45.The part of overdriving 46 is carried out the processing that is used for determining the output gray level value according to the vision signal of last subframe and the vision signal of current subframe with reference to LUT 461.
(B) two kinds of signals are imported into the part 46 of overdriving for X=R, G from the Xold of memory portion 21 and Xnew.Here, Xnew is the gray-scale signal of current subframe, and Xold is the subframe signal of last subframe in the same pixel.
Number of sub-frames from counter and control signal generating portion 44 is sent to the part 46 of overdriving as count value, this with above-mentioned each embodiment in the same.In addition, beyond the gray-scale signal of current subframe, also be imported into the part 46 of overdriving from the subframe gray-scale signal of the last subframe of memory portion 21.The part of overdriving 46 is used LUT 461, carries out grey level transition according to the number of sub frames of input and the gray-scale signal of input, this with second embodiment in the same.Then, according to carrying out grey level transition (processing of overdriving), current subframe is carried out grey level transition gray-scale value afterwards so that the gray-scale value after the period of sub-frame arrives by grey level transition and the gray-scale value that conversion gray-scale value before obtains.Here, consider the response time of liquid crystal, the processing execution of overdriving grey level transition makes luminance component arrive expectation value during a frame period.
Specifically, overdrive to handle and refer to this processing, promptly the display gray scale in the pixel 35 of liquid-crystal display section 12 changes under the situation of 192 gray levels from 64 gray levels shown in Figure 27 A, gray-scale value change into 64,224,192 ..., and general gray-scale value change into 64,192,192 ....That is to say, in the method for handling of overdriving, under the situation that increases gray-scale value when the gray-scale value of generation during greater than the original gray level value, be imported into this pixel less than the value of original gray level value.
Because shortened the time that arrives expectation intermediate grey scales value by the overdriving processing of carrying out shown in Figure 27 B, the response time just as liquid crystal when therefore carrying out demonstration has been shortened.But, gray level is being changed to maximum gray scale and the minimal gray level (words of representing with 8 bits, be exactly 0 gray level (deceiving) and 255 gray levels (in vain)) situation under, can not input to pixel greater than the gray level of (or less than) original gray level value, thereby and can't carry out the processing of overdriving.
Here, in the design liquid crystal display, by consider by white to black or by black to faster from which response time, to change the LUT461 that is used to carry out grey level transition under the preferable case.For example, usually, under the situation of general white TN (twisted nematic) liquid crystal, by white to the black response time than by black fast to the white response time.At this moment, from being almost the 3rd black subframe to the response of first subframe of subsequent subframe, the response nargin that compares white to the response nargin of intermediate grey scales is big.Therefore, in this case, use LUT 461 under the preferable case, it has distributed to second frame with maximum gray scale, as shown in figure 28.
Figure 29 A shows at the response wave shape of maximum gray scale being distributed under first word frame condition, and Figure 29 B shows the response wave shape in the present embodiment of use LUT as shown in figure 28.These waveforms are that the gray-scale value in each subframe is the example under 255,192 and 0 the situation.Here, suppose the response time of (responses of from 255 to 0 gray levels) liquid crystal under response time at (response of from 0 to 255 gray level) liquid crystal under the situation that gray-scale value increases is greater than situation about reducing at gray-scale value.
Shown in Figure 29 A, when gray-scale value 255 is distributed to first subframe, gray-scale value 192 is distributed to second subframe, and when gray-scale value 0 distributed to the 3rd subframe, need liquid crystal during first period of sub-frame, to respond from minimal gray level value 0 to maximum gray scale value 255.And, because the original gray level value is a maximum gray scale in this case, therefore can't carry out the processing of overdriving.Therefore, under the situation that response speed of liquid crystal is lower when increasing progressively gray-scale value, do not finish the response of liquid crystal during first period of sub-frame, overall brightness will be not enough in a frame period for the result.
On the other hand, shown in Figure 29 B, when gray-scale value 192 is distributed to first subframe, gray-scale value 255 is distributed to second subframe, and when gray-scale value 0 is distributed to the 3rd subframe, need liquid crystal during first period of sub-frame, only to respond from 0 to 192 gray level variation, and and then can handle by overdriving and shorten the response time.Although need liquid crystal during second period of sub-frame, to respond from 192 to 255 gray level variation, but therefore the scope that gray level changes does not need to carry out the processing of overdriving and just can finish response less than the variation range in first subframe during second period of sub-frame.
Here, though the situation of the low-response when having told about the response ratio minimizing gray-scale value when increasing gray-scale value, but it is opposite, response when increasing gray-scale value is faster under the situation, by avoiding before subframe being used as the source that is used to distribute gray-scale value, the high grade grey level value being distributed to this subframe, can obtain same effect.
According to response speed of liquid crystal LUT 461 is applied to liquid crystal display, in the processing of overdriving, provides a nargin, to prevent to reduce brightness.
Like this, even under the situation of the response time of display element, overdrive by use and to handle the response speed that improves display element, also can under the situation that does not reduce brightness, improve the motion picture quality greater than period of sub-frame.
Above-mentioned each embodiment is the example of preferred enforcement of the present invention, and the present invention is not limited to these embodiment.
For example, although in above-mentioned each embodiment, explained the situation (will output to the method for pixel) of independent use display-apparatus driving method corresponding to the signal of black, but even backlight in conjunction with flicker and use similar approach such as electronic shutter implementing under the situation of this method, also can obtain with above-mentioned situation in the same effect.
Therefore, can carry out various corrections to the present invention.

Claims (15)

1. image processing method, wherein the vision signal in a frame period is time-divided into a plurality of subframes, and wherein at least a portion of the luminance component of the vision signal of predetermined subframe is assigned to the vision signal of undersaturated other subframes of luminance component.
2. image processing method as claimed in claim 1, wherein said vision signal are the gray-scale signals of expression display element output level, and the gray-scale value of the vision signal of wherein said subframe is assigned to the vision signal of other subframes.
3. image processing method as claimed in claim 1, wherein before the distribution of luminance component and afterwards, the overall brightness in a frame period does not change.
4. image processing method as claimed in claim 1, wherein for any vision signal of a plurality of color components of forming coloured image, at least a portion of the luminance component of the vision signal of predetermined subframe is assigned to the vision signal of undersaturated other subframes of luminance component with identical ratio, and described ratio is determined according to the gray level of the color component with maximum overall brightness.
5. one kind is used for coming at the driving method of display element with the maintenance display device of predetermined period display light with the brightness corresponding to incoming video signal, the vision signal that wherein is used for a frame period is time-divided into a plurality of subframes, wherein at least a portion of the luminance component of the vision signal of predetermined subframe is assigned to the vision signal of undersaturated other subframes of luminance component, and wherein its brightness shows by described display element in each period of sub-frame corresponding to the light of the vision signal of each subframe that has been assigned with luminance component.
6. the driving method of maintenance display device as claimed in claim 5, wherein said vision signal is the gray-scale signal of the output level of the described display element of expression, and the gray-scale value of the vision signal of wherein said predetermined subframe is assigned to the vision signal of other subframes.
7. the driving method of maintenance display device as claimed in claim 5, wherein before the distribution of luminance component and afterwards the overall brightness in a frame period does not change.
8. the driving method of maintenance display device as claimed in claim 5, the colour-video signal that wherein said vision signal is made up of a plurality of color components, and wherein for each color component, at least a portion of the luminance component of the vision signal of predetermined subframe is assigned to the vision signal of undersaturated other subframes of luminance component with identical ratio, and described ratio is determined according to the gray level of the color component with maximum overall brightness.
9. display device, comprising: image processing apparatus is used for after the vision signal of being imported is carried out Flame Image Process the vision signal of being imported being exported as gray-scale signal; And display device, be used for brightness corresponding to the gray-scale signal of exporting from described image processing apparatus, carry out picture and show.
Described image processing apparatus comprises:
The device that is divided into a plurality of subframes when being used for the vision signal with a frame; And
Be used to specify the device of each time-division subframe sequence number, this sequence number is assigned to each subframe in the frame; And
The grey level transition device is used to described each subframe to generate gray-scale signal, so that at least a portion of the luminance component of the vision signal of predetermined subframe is distributed to the vision signal of undersaturated other subframes of luminance component.
10. display device as claimed in claim 9, wherein said grey level transition device is by carrying out the four fundamental rules fundamental operation or with reference to look-up table, at least a portion of the luminance component of the vision signal of predetermined subframe distributed to the vision signal of undersaturated other subframes of luminance component.
11. a display device comprises: the gray-scale voltage generating apparatus is used for generating the gray-scale voltage signal according to the vision signal of input, and is used for the output gray level magnitude voltage signals; And display device, be used for carrying out screen display corresponding to the brightness of described gray-scale voltage signal,
Described display device further comprises: the device that is divided into a plurality of subframes when being used for a frame video signal; And
Be used to specify the device of sequence number of the vision signal of each time-division subframe, this sequence number is assigned to each subframe in the frame; And
Make described gray-scale voltage generating apparatus generate the device of described gray-scale voltage signal thereby be used to change reference value, so that at least a portion of the luminance component of the vision signal of predetermined subframe is distributed to the vision signal of undersaturated other subframes of luminance component.
12. display device as claimed in claim 9, the colour-video signal that wherein said vision signal is made up of a plurality of color components, and wherein for each color component, at least a portion of the luminance component of the vision signal of predetermined subframe is assigned to the vision signal of undersaturated other subframes of luminance component with identical ratio, and described ratio is determined according to the gray level of the color component with maximum overall brightness.
13. display device as claimed in claim 9, wherein before the distribution of luminance component and afterwards the overall brightness in a frame period does not change.
14. a display device comprises: image processing apparatus is used for after the vision signal of being imported is carried out Flame Image Process the vision signal of being imported being exported as gray-scale signal; And display device, be used for showing that to carry out picture wherein said image processing apparatus is carried out image processing method as claimed in claim 1 to the vision signal of described input corresponding to the brightness of the gray-scale signal of exporting from described image processing apparatus.
15. a display device is used for carrying out picture according to the driving method of maintenance display device as claimed in claim 5 and shows.
CNB2005100094476A 2005-02-16 2005-02-16 Image processing method, display device and its driving method Active CN100456350C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CNB2005100094476A CN100456350C (en) 2005-02-16 2005-02-16 Image processing method, display device and its driving method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CNB2005100094476A CN100456350C (en) 2005-02-16 2005-02-16 Image processing method, display device and its driving method

Publications (2)

Publication Number Publication Date
CN1822086A CN1822086A (en) 2006-08-23
CN100456350C true CN100456350C (en) 2009-01-28

Family

ID=36923419

Family Applications (1)

Application Number Title Priority Date Filing Date
CNB2005100094476A Active CN100456350C (en) 2005-02-16 2005-02-16 Image processing method, display device and its driving method

Country Status (1)

Country Link
CN (1) CN100456350C (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5278730B2 (en) 2008-04-16 2013-09-04 Nltテクノロジー株式会社 CONTROLLER, HOLD TYPE DISPLAY, ELECTRONIC DEVICE, SIGNAL ADJUSTMENT METHOD FOR HOLD TYPE DISPLAY
CN106504717B (en) * 2016-12-27 2018-01-12 惠科股份有限公司 The driving method and display device of a kind of display device
CN107610660B (en) 2017-09-18 2019-08-09 惠科股份有限公司 A kind of driving method and display device of display device
CN110910429B (en) * 2019-11-19 2023-03-17 成都市联洲国际技术有限公司 Moving target detection method and device, storage medium and terminal equipment

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000148084A (en) * 1998-11-09 2000-05-26 Matsushita Electric Ind Co Ltd Driving method of plasma display
US6127991A (en) * 1996-11-12 2000-10-03 Sanyo Electric Co., Ltd. Method of driving flat panel display apparatus for multi-gradation display
CN1406369A (en) * 2000-12-27 2003-03-26 松下电器产业株式会社 Method for driving liquid crystal display panel and liquid crystal display device
EP1353315A1 (en) * 2002-04-11 2003-10-15 Thomson Licensing S.A. Method and apparatus for processing video pictures to improve grey scale resolution of a display device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6127991A (en) * 1996-11-12 2000-10-03 Sanyo Electric Co., Ltd. Method of driving flat panel display apparatus for multi-gradation display
JP2000148084A (en) * 1998-11-09 2000-05-26 Matsushita Electric Ind Co Ltd Driving method of plasma display
CN1406369A (en) * 2000-12-27 2003-03-26 松下电器产业株式会社 Method for driving liquid crystal display panel and liquid crystal display device
EP1353315A1 (en) * 2002-04-11 2003-10-15 Thomson Licensing S.A. Method and apparatus for processing video pictures to improve grey scale resolution of a display device

Also Published As

Publication number Publication date
CN1822086A (en) 2006-08-23

Similar Documents

Publication Publication Date Title
US7924251B2 (en) Image processing method, display device and driving method thereof
CN101188093B (en) Liquid crystal display and driving method thereof
KR100592385B1 (en) Driving Method and Driving Device of Liquid Crystal Display
CN100505021C (en) Display device, apparatus for driving the same and method of driving the same
CN100426057C (en) Liquid crystal display device and method for driving liquid crystal display device
CN101038411B (en) Liquid crystal driving device
US9875680B2 (en) Method and apparatus for generation of gray scale adjustment voltage and panel driver circuit
KR101146408B1 (en) Display and Driving Method thereof
KR20050069870A (en) Method and apparatus for driving liquid crystal display
WO2007026551A1 (en) Display device, display method, display monitor, and television set
US11869439B2 (en) Display apparatus reducing power consumption and method of driving display panel using the same
US10019951B2 (en) Display apparatus and method for driving display apparatus
CN100456350C (en) Image processing method, display device and its driving method
CN101138018A (en) Display devices and driving methods therefor
CN101499234A (en) Image display apparatus, method for controlling the same, and electronic device
KR101363652B1 (en) LCD and overdrive method thereof
KR101517392B1 (en) Display device and method for driving the same
KR100949492B1 (en) Method and Apparatus for Driving Liquid Crystal Display Device
KR101264689B1 (en) Liquid crystal display device and driving method thereof
JP4421653B2 (en) Display device, drive control device thereof, and display method
KR20050000658A (en) Method and Apparatus for Driving Liquid Crystal Display Device
US20070205973A1 (en) Method for driving lcd panels
KR101186098B1 (en) Display and Driving Method thereof
KR20050120264A (en) Method and apparatus for driving liquid crystal display
JP4254963B2 (en) Liquid crystal display

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
ASS Succession or assignment of patent right

Owner name: JINZHEN CO., LTD.

Free format text: FORMER OWNER: NEC CORP.

Effective date: 20130509

C41 Transfer of patent application or patent right or utility model
TR01 Transfer of patent right

Effective date of registration: 20130509

Address after: Samoa Apia hiSoft Center No. 217 mailbox

Patentee after: Jinzhen Co.,Ltd.

Address before: Tokyo, Japan

Patentee before: NEC Corp.

TR01 Transfer of patent right
TR01 Transfer of patent right

Effective date of registration: 20230525

Address after: Floor 4, No. 15, Lane 168, Xingshan Road, Neihu District, Taipei City, Taiwan, China, 114762, China

Patentee after: HANNSTAR DISPLAY Corp.

Address before: Apia, hiSoft center, No. 217 mailbox

Patentee before: Jinzhen Co.,Ltd.