General introduction of the present invention
In sum, thus the purpose of this invention is to provide a kind of method for displaying image and a kind of scale that is used for to the power circuit of back lighting power supply that can make when being presented on the transmissive liquid crystal display device in transmissive liquid crystal display device to the image is made up of motion picture and still frame diminishes, makes power circuit to become the transmissive liquid crystal display device that at a low price and power consumption that make back lighting reduces minimizing scintillation, trace phenomenon and image retention phenomenon.Therefore, can obtain the suitable display characteristic of display characteristic that provides with CRT.
According to a first aspect of the present invention, provide a kind of be used for comprise LCD and from the transmissive liquid crystal display device of back luminous back lighting of LCDs to LCDs the method for display image, this method comprises:
According to the testing result of image motion by between picture signal and non-image signal, changing and by described picture signal and described non-image signal are added to the step that numerous data electrodes of forming LCD come display image signals or are different from the non-image signal of picture signal.
Adopt above-mentioned configuration, when the image of being made up of motion picture and still frame is presented on the LCD, to the power circuit of back lighting power supply can become miniaturization with at a low price, and the power consumption of back lighting can be reduced.In addition, it is possible reducing the scintillation, trace phenomenon and the image retention phenomenon that take place on display screen, and the display characteristic that the acquisition level is identical with the display characteristic of CRT monitor also is possible.
In the description in front, preferred pattern is a kind of like this pattern, and one of them or numerous motion picture parameter are according to coming self-monitoring result to be controlled.
Adopt above-mentioned configuration, when the motion of the image that plan to show is fast the time, control can be added up like this, so that the motion picture parameter is made response to motion fast, when the motion of the image that plan to show is slowly the time, though the motion picture parameter can not be made response to motion slowly, the beautiful image of acquisition is possible on the screen by being controlled at.For example, when the motion of image is fast the time, although show that the speed of non-image signal is increased gradually during a frame period, control is utilization like this, so that the level of non-image the signal all level of more approaching white rather than the level of black.By above-mentioned control, though the minimizing of display brightness can be avoided, black floats, and contrast reduces.In other words, when the motion of image is fast the time, rapid movement is accompanied by the sacrifice contrast.On the other hand, when the motion of image is slowly the time, the speed that shows non-image signal during a frame period and the level of non-image signal be control like this so that signal level becomes the level of black.By above-mentioned configuration, display brightness and contrast all increase.In other words, when the motion of image became low speed, though can not follow motion fast, the image with high brightness and contrast can be realized.The motion picture parameter is not limited to the parameter of describing in embodiments of the invention.The motion picture parameter comprises, for example, is used to control the parameter of overshoot.
In addition, preferred pattern is a kind of like this pattern, and non-image signal wherein is the corresponding signal of signal level with certain regulation of picture signal.
In addition, preferred pattern is a kind of like this pattern, and non-image signal wherein is the corresponding signal of picture black with certain regulation of picture signal.
In addition, preferred pattern is a kind of like this pattern, and motion picture parameter wherein comprises one of following parameter at least: the speed, the signal level of non-image signal and the illumination of back lighting that show non-image signal during a frame period.
In addition, preferred pattern is a kind of like this pattern, and it is detected or be included in the size of the motion vector in the picture signal from image wherein coming self-monitoring result.
Adopt above-mentioned configuration, control can be used like this, so that the motion picture parameter can change according to the size of motion vector, can obtain high-quality image like this.
In addition, preferred pattern is a kind of like this pattern, and it is detected or be included in the size of the motion vector the most fast in the picture signal in certain regulation zone of image from certain regulation zone of image wherein coming self-monitoring result.
In addition, preferred pattern is a kind of like this pattern, wherein respond result from the detection of motion of image, when image when still frame changes to motion picture, control is like this utilization, so that the motion picture parameter promptly follows self-monitoring result, when image when motion picture changes to still frame, control is utilization like this, so that the motion picture parameter follows self-monitoring result lentamente.
Adopt above-mentioned configuration, control can be used like this, so that the part of only changing between motion picture and still frame, the part graded in accordance with regulations of promptly having only display brightness to change.This makes the observer to watch under the situation of the sensation that does not have to upset.
In addition, preferred pattern is a kind of like this pattern, promptly when the motion vector size changes on the direction that this yardstick increases progressively, control is utilization like this, so that in the change of the motion picture parameter size of accompany movement vector promptly, when the motion vector size changed on the direction that this yardstick successively decreases, control was like this utilization, so that in the change of the motion picture parameter size of accompany movement vector lentamente.
In addition, preferred pattern is a kind of like this pattern, promptly when the direction of the control that comes self-monitoring results change to increase progressively to the speed that need cause the non-image signal of demonstration during a frame period, control is utilization like this, so that the variation in the motion picture parameter is the size of accompany movement vector promptly, when the direction of the control that comes self-monitoring results change to successively decrease to the speed that need cause the non-image signal of demonstration during a frame period, control is like this utilization, so that the size of accompany movement vector lentamente of the variation in the motion picture parameter.
In addition, preferred pattern is a kind of like this pattern, convert non-image signal to and be added to numerous data electrodes of forming LCDs after the picture signal experience gamma correction wherein, and motion picture parameter wherein comprises the information about gamma correction.
Adopt above-mentioned configuration, exist several change back lightings illumination, change the situation of the spectrum of light source.During this time, by the characteristic that control is carried out gamma correction to picture signal, the chromatic characteristic of the image that is shown can access adjustment.
In addition, preferred pattern is a kind of like this pattern, be used for wherein on numerous main scanning display lines of LCD showing that the Displaying timer of non-image signal sets by this way, so that when non-image signal is presented on numerous main scanning display lines, there is the superimposed time cycle of Displaying timer, and is closed in back lighting during the superimposed cycle of Displaying timer or during the Displaying timer part in superimposed cycle.
In addition, preferred pattern is a kind of like this pattern, the Displaying timer that wherein is used for showing non-image signal on two of LCD or many main scanning display lines is for per two or many main scanning display lines or to be configured to for every two or more be different, and partly is closed corresponding to two or many main scanning display lines or two or more back lighting.
Preferred pattern is a kind of like this pattern, and wherein the Displaying timer of non-image signal is used for presenting to numerous data electrodes the control of the timing of non-image signal.
Preferred pattern is a kind of like this pattern, wherein image is made up of numerous windows, and between picture signal that is used for each window and non-image signal, switch according to result from the detection of motion of image, and through numerous data electrodes that the signal that switching is sent to the composition LCD, so that display image signals or non-image signal.
Adopt above-mentioned configuration, in the presence of all windows display on LCD in, if it is different planning the displaying contents type of the picture signal that shows at each window, kinematic parameter can be controlled in each window so.Therefore, in this case, high-quality image can obtain.
Preferred pattern is a kind of like this pattern, and one of them or numerous motion picture parameter are from the result of the detection of motion of the image of forming this window or according to coming self-monitoring result, the type of image or the size of window to control at each window basis.
Adopt above-mentioned configuration, the motion that is shown image is the notion that derives from the size that is independent of the window that is shown.Yet the true velocity of object depends on the size of screen.For example, the problem that why does not have liquid crystal servo-actuated service speed on 5-type LCD is because display screen is so little, and speed is 1/10th of 50-type LCD.Therefore, by the controlled motion frame parameter, according to the size that is shown window, the speed of servo-actuated operation can use the real motion speed of object to obtain calibration on display screen.Furtherly, the speed of observer's visual experience depends on two formed angles of point that object moves betwixt during the official hour cycle, promptly depends on the size at visual angle.In addition, the speed of the true velocity of object on display screen is not only depended at the visual angle, and depends on the distance between display screen and the observer.So for the movement velocity controlled motion frame parameter of feeling with the observer, control must be to apply by the size of the result of the detection of motion of the image that constitutes window, window and the distance from the display screen to observer.Yet, because the distance between display screen and the observer do not change according to the time, though this distance is sure be not included in as Control Parameter in, it also drops within the initial value scope.In some cases, the motion that is about to the image of demonstration can be passed through the type prediction of the image of demonstration soon.For example, in sports cast the motion of image just the motion than image in the general news program is fast.So according to the type of image, the motion picture parameter can be controlled.
Preferred pattern is a kind of like this pattern, wherein basis is from the result of the detection of motion of the image that constitutes window, when image is determined when being motion picture, picture signal and non-image signal are sent to numerous data electrodes during a frame period, when image is determined when being rest image, picture signal only is sent to numerous data electrodes twice or repeatedly during a frame period.
Preferred pattern is a kind of like this pattern, and wherein the motion picture parameter comprises speed, the level of non-image signal and the illumination of back lighting that is used for showing non-image signal during a frame period.
Preferred pattern is a kind of like this pattern, wherein picture signal is converted into non-image signal after experience gamma correction, be added to numerous data electrodes of forming LCD then, and motion picture parameter wherein comprises the information about gamma correction.
Preferred pattern is a kind of like this pattern, and wherein the multiplication coefficient with the corresponding regulation of motion picture parameter that is used for window is multiplied by the picture signal of forming window, and is applied to numerous data electrodes from the result of multiplying.
Preferred pattern is a kind of like this pattern, and wherein multiplication coefficient is the coefficient that reduces the discontinuous variation of the display brightness that is caused by the discontinuous variation that shows the speed of the non-image signal of forming window during a frame period.
Preferred pattern is a kind of like this pattern, and wherein multiplication coefficient comprises the information about gamma correction.
Preferred pattern is a kind of like this pattern, wherein the level of non-image signal and to be determined at image in the speed that shows non-image signal during the frame period be to be identical between numerous windows of motion picture.
Preferred pattern is a kind of like this pattern, and wherein to be judged be that numerous windows of motion picture are not shared identical main scanning display line in liquid crystal indicator to image.
According to a second aspect of the present invention, provide have LCD and from the back of LCD to the transmission-type liquid liquid crystal indicator of the luminous back lighting of LCD, this device comprises:
Be used for the detection of motion circuit of detected image; And
By according to from the result of the detection of motion of image in picture signal be different from and switch between the non-image signal of picture signal and by using the control circuit that numerous data electrodes of forming LCD come display image signals or non-image signal.
Adopt above-mentioned configuration, when image by motion picture form and rest image when being presented on the LCD, to the power circuit of back lighting power supply can become miniaturization, at a low price, power consumption also can reduce.In addition, it is possible reducing scintillation, trace phenomenon and the image retention phenomenon and the acquisition level display characteristic identical with the display characteristic of CRT monitor that occur on display screen.
According to a third aspect of the present invention, a kind of transmissive liquid crystal display device according to claim 25 is provided, wherein control circuit is according to coming self-monitoring result to control one or numerous motion picture parameter.
Adopt above-mentioned configuration, when the motion of the image that is shown is fast the time, control can be utilization like this, so that kinematic parameter is made a response to motion fast, when the motion that is shown image is slowly the time, though kinematic parameter can not be made a response to motion slowly, control can make the image on the screen look may be as smart as a new pin.For example, when the motion of image is fast, the speed that is used for during a frame period, showing non-image signal simultaneously be increase progressively in, control is utilization like this, so that the level of the very approaching white of level of non-image signal rather than the level of black.By above-mentioned control, though the minimizing of display brightness can be avoided, black is floating, contrast descends.In other words, when the motion of image is fast the time, rapid movement is accompanied by the sacrifice contrast.On the other hand, when the motion of image is slowly the time, be used for during a frame period, showing that the level of the speed of non-image signal and non-image signal is controlled like this, so that signal level becomes the level of black.By above-mentioned configuration, display brightness and contrast all increase to some extent.In other words, when the motion of image is slack-off,, there is the image of high brightness and contrast to realize though motion can not be followed fast.The motion picture parameter is not limited to institute's characterising parameter in embodiments of the invention.For example, motion picture comprises the parameter that is used for overshoot control.
Hereinbefore, preferred pattern is a kind of like this pattern, and wherein non-image signal is the signal corresponding to the signal level of certain regulation of picture signal.
In addition, preferred pattern is a kind of like this pattern, and wherein non-image signal is the signal corresponding to the signal level of certain regulation of picture signal.
In addition, preferred pattern is a kind of like this pattern, and wherein the motion picture parameter is to be made up of one of following parameter at least: the speed, the signal level of non-image signal and the illumination of back lighting that show non-image signal during a frame period.
In addition, preferred pattern is a kind of like this pattern, and it is detected or be included in the size of the motion vector in the picture signal from image wherein coming self-monitoring result.
In addition, preferred pattern is a kind of like this pattern, and it is detected or be included in the picture signal in the zone of certain regulation of image the size of motion vector the most fast from the zone of certain regulation of image wherein coming self-monitoring result.
In addition, preferred pattern is a kind of like this pattern, wherein control circuit response is to the result from the detection of motion of image, when image applies control like this when still frame changes to motion picture, so that the motion picture parameter promptly follows self-monitoring result, when image applies control like this when motion picture changes to still frame, so that the motion picture parameter follows self-monitoring result lentamente.
Adopt above-mentioned configuration, control can be used like this, so that the motion picture parameter can change according to the size of the motion vector that can obtain high quality graphic.
In addition, adopt above-mentioned configuration, control can be used like this, so that the part only switched between motion picture and still frame, and the part of promptly having only display brightness to change is that in accordance with regulations gradient changes.This can watch the observer not having under the situation of confused.
In addition, preferred pattern is a kind of like this pattern, wherein control circuit applies control like this when the size of motion picture changes on the direction of described size increments, so that the variation of motion picture parameter is the size of accompany movement vector promptly, when changing, the size of motion picture applies control like this on the direction that described size is successively decreased, so that the variation of the motion picture parameter size of accompany movement vector lentamente.
In addition, preferred pattern is a kind of like this pattern, wherein control circuit applies control like this when coming self-monitoring result to change to must to have to cause the direction that shows the control that the non-image speed of making signal increases gradually during a frame period, so that the variation aspect the motion picture parameter is the size of accompany movement vector promptly, when coming self-monitoring result to change to must to have to cause the direction that during a frame period, shows the control that the non-image speed of making signal reduces gradually, apply control like this, so that the size of accompany movement vector lentamente of the variation aspect the motion picture parameter.
In addition, preferred pattern is a kind of like this pattern, comprising the gamma-correction circuit that picture signal is carried out gamma correction, wherein control circuit is becoming non-image signal and it is sent to numerous data electrodes of forming LCD from the output signal of gamma-correction circuit, and wherein the motion picture parameter comprises information about gamma correction.
Adopt above-mentioned configuration, have the illumination of several back lightings to change and situation that the spectrum of light source changes.During this time, by the characteristic of control to the gamma correction of picture signal, the chromatic characteristic of the image that is shown can access adjustment.
In addition, preferred pattern is a kind of like this pattern, wherein control circuit is set and to be used for the Displaying timer that has certain period, the superimposed mode of Displaying timer shows non-image signal on numerous main scanning display lines of LCD when non-image signal is presented on numerous main scanning display lines in this period, and wherein back lighting during Displaying timer is superimposed or a part of Displaying timer be switched off during superimposed.
In addition, preferred pattern is a kind of like this pattern, wherein control circuit is set Displaying timer, adopt the non-image signal of this Displaying timer to be presented at like this on two of LCD or many main scanning display lines, so that for per two or many main scanning display lines or every two or more non-image signals is different, and turns off and described two or many main scanning display lines or two or more corresponding those partly back lightings.
In addition, preferred pattern is a kind of like this pattern, wherein the control circuit Displaying timer that transmits the non-image signal of timing controlled of non-image signal to numerous data electrodes.
In addition, preferred pattern is a kind of like this pattern, wherein image is made up of numerous windows, and control circuit switches between picture signal that is used for each window and non-image signal according to the testing result of image motion, and sending numerous data electrodes of forming LCD to, so that display image signals or non-image signal through the signal that switches.
Adopt above-mentioned configuration, in the presence of all windows display on LCD in, if the kind of the content of the picture signal that shows in each window is different, the motion picture parameter can be controlled in each window so.So in this case, high-quality image can obtain.
In addition, preferred pattern is a kind of like this pattern, and wherein the control circuit basis is controlled or the numerous motion picture parameter that is used for each window from the result of the detection of motion of the image of forming window or according to the size of type of coming self-monitoring result, image or window.
In addition, preferred pattern is a kind of like this pattern, wherein control circuit according to the result of the detection of motion of the image of forming window and image be determined be motion picture in, in during the frame period, picture signal and non-image signal are sent to numerous data electrodes, and image be determined be still frame in, only picture signal and non-image signal are sent to twice of numerous data electrode or repeatedly in during the frame period.
In addition, preferred pattern is a kind of like this pattern, and wherein the motion picture parameter is the level and the illumination of non-picture signal when showing non-image signal in during a frame period.
In addition, preferred pattern is a kind of like this pattern, wherein control circuit becomes non-image signal to this picture signal after finishing the gamma correction of picture signal, then it is added on numerous data electrodes of forming LCD, and wherein the motion picture parameter comprises information about gamma correction.
Preferred pattern is a kind of like this pattern, and wherein the control circuit handle multiply by the picture signal of forming window with the multiplication coefficient of the corresponding regulation of motion picture parameter that is used for window, and the result from multiplying is sent to numerous data electrodes.
Preferred pattern is a kind of like this pattern, and wherein multiplication coefficient is the coefficient that reduces the discontinuous variation of the display brightness that is caused by the discontinuous variation that shows the speed of the non-image signal of forming window during a frame period.
Preferred pattern is a kind of like this pattern, and wherein multiplication coefficient comprises gamma correction.
Preferred pattern is a kind of like this pattern, and wherein control circuit is adjusted like this, so that the level of non-image signal and judged respectively that at numerous images wherein being is identical between the window of motion picture in the speed that shows non-image signal during the frame period.
In addition, preferred pattern is a kind of like this pattern, and wherein numerous images have wherein been judged it is that the window of motion picture is not shared identical main scanning display line in the liquid crystal indicator respectively.
Adopt above-mentioned configuration, switching is according to carrying out between the picture signal of composition diagram picture and non-image signal from the result of the detection of motion of image, and the data electrode of numerous composition liquid crystal indicators is for display image signals and non-image signal and adopted.So, be made into for the power circuit of back lighting power supply the miniaturization that reduces power consumption with at a low price.In addition, can obtain liquid crystal indicator, its display characteristic level is identical with CRT monitor, and scintillation, trace phenomenon and image retention phenomenon can be reduced.
Detailed description of the present invention
Realize that best mode of the present invention further describes in detail with various embodiments with reference to the accompanying drawings.
First embodiment
Fig. 1 be represent according to first embodiment of the present invention use on color LCD display image the block diagram of configuration of transmissive liquid crystal display device of method.The transmissive liquid crystal display device of first embodiment comprises color LCD 1, motion detection circuit 2, control circuit 3, frame memory 4, blanking regularly generative circuit 5, gamma-correction circuit (gamma correction circuit) 6, data converting circuit 7, data electrode driver circuit 8, scan electrode driving circuit 9, back lighting 10 and inverter 11.
Color LCD 1 is to use the active matrix drive-type color LCD of TFT (thin-film transistor) as switch element.In the color LCD 1 of first embodiment, used as the pixel (not shown) by the scan electrode (not shown) of placing by the interval of determining on numerous directions of being expert at (gate line) and numerous data electrode (not shown) (source electrode line) area surrounded of on the direction of row, placing by the interval of determining.Each pixel of the color LCD 1 of this embodiment all has as the liquid crystal cells (not shown) of equivalent electric capacitive load, common electrode (not shown), drives the TFT (not shown) of corresponding liquid crystal unit and accumulate the capacitor (not shown) of a data charge in the vertical sync period.In order to drive this color LCD 1, as utility voltage V
ComWhen (not shown) is added on the common electrode, respectively based on all as the red data D of digital of digital video data
R, green data D
GWith blue data D
BThe red data signal, green data signal and the data blue signal that produce are sent to data electrode, simultaneously based on horizontal-drive signal S
HWith vertical synchronizing signal S
VThe sweep signal that produces is sent to scan electrode.This makes colored character, image or similar thing be presented on the display screen of color LCD 1.This color LCD 1 is called as WXGA (wide XGA (Extended Graphics Array)), and in this embodiment, it provides 1365 * 768 pixel resolutions.A pixel comprises three some pixels that are used for redness (R), green (G) and blue (B), so the sum of some pixel is " 3 * 1365 * 768 ".
Motion detection circuit 2 is from by all as the red data D of digital of digital video data feed-in from the outside
B, green data D
GWith blue data D
BDetect numerous motion vectors in the image of forming, extract the fastest vector from a plurality of motion vectors, then it as motion vector data D
VBe sent to control circuit 3.Be used for being divided into three types method, described below from the method for motion picture detection motion vector.First kind of method that detects motion vector is the method that is called " BMA ".In BMA, employed technological concept is with used identical in pattern matching.In other words, whether the zone that gets clogged in present image exists and is to check by present image and the image of passing by are compared in the somewhere in the past the image.More particularly, the differential absolute value is by each corresponding pixel addition in piece, and the position that differential absolute value sum becomes minimum value in each piece is used as motion vector and uses.This method provides high measurement accuracy, has shortcoming but become in the amount of calculation of operation aspect huge.
The second method that is used for detecting motion vector is the method that is called " gradient method ".This gradient method is based on following model: time certain position, corresponding time aspect producing difference with amount of exercise as the image motion of spatial gradient.Therefore, motion vector can obtain by pressing spatial gradient difference sliced time.In this method, more a spot of operational computations is essential, yet when the motion quantitative change was big, the precision of detection reduced.This is because above-mentioned model does not contain.
The third method that is used for detecting motion vector is the method that is called " phase correlation method ".In this method, after finishing to the Fourier transform that is present in the present image locational blocks of data identical with image in the past, the side-play amount of phase place is detected in certain frequency range, utilizes completed phase term to carry out inverse-Fourier transform in order to detect motion vector then.The characteristic of this method be for the size of the precision block that guarantees to detect must be bigger than the level of regulation.This proposes the huge problem of operational computations amount of a Fourier transform.In addition, have another shortcoming, that is exactly because the accuracy of detection of motion vector equals pixel is carried out the precision of the pixel of Fourier transform, so the vector that can obtain only is the motion vector of input pixel pitch.
In addition, with regard to the details of the configuration of the method that is used for detecting motion vector and motion vector detecting circuit and operation, please refer to Japanese Patent Application Publication Hei9-93585 and Hei9-212650 number.
Above-mentioned first to the third motion vector detecting method selected which kind of method for testing motion can according to the configuration of control precision essential when using method for displaying image of the present invention, the control circuit that uses at that time, in the motion vector detecting circuit coupling or similarly thing determine.
For example, control circuit 3 is made up of ASIC (application-specific IC).Control circuit 3 responds the horizontal-drive signal S of feed-in from the outside
HWith vertical synchronizing signal S
VControl data change-over circuit 7, data electrode driver circuit 8 and scan electrode driving circuit 9.In addition, control circuit 3 is according to the motion vector data D from motion detection circuit 2 feed-ins
VSize select blanking sign indicating number BC and it be supplied to blanking timing generation circuit 5 and inverter 11.Fig. 2 represents an example of the relation between blanking sign indicating number BC and the blanking ratio.Blanking that is to say than pointing out during a frame period the not speed of the time cycle of display image, and it is the speed of time cycle that blanking is provided of representing with percentage.Blanking is than being with the value appointment of blanking sign indicating number BC.In addition, control circuit 3 produces gamma correction code GC and it is offered gamma-correction circuit 6 according to the motion vector data DV from motion vector detecting circuit 2 feed-ins.This gamma correction code GC will make an explanation after a while.Hereinafter, blanking sign indicating number BC, gamma correction code GC, blanking level (BL) (below described) and the illumination of back lighting are collectively referred to as " motion picture parameter ".
Frame memory 4 is made up of the semiconductor memory such as RAM (random access memory), and it stores the red data D by the digital of digital video data of conduct feed-in from the outside
R, green data D
GWith blue data D
BNumerous two field pictures of forming.Why use frame memory 4 to be because following reason.In other words, for example, shown in the waveform among Fig. 3, as above-mentioned motion vector data D
VWhen promptly changing, if the motion picture parameter changes consistently with this rapid variation, image retention phenomenon and/or trace phenomenon will take place so, thereby cause image quality decrease.As motion vector data D
VAs in Fig. 3 with waveform " a " show vertiginous the time, kinematic parameter as in Fig. 3 with waveform " b " show according to relying at motion vector data D
VThe predetermined rate of change of several frames before taking place to change rapidly changes.This feasible possibility that becomes that reduces image retention phenomenon and/or trace phenomenon, thus image quality decrease prevented.
Blanking timing generation circuit 5 produces according to the blanking sign indicating number BC from control circuit 3 feed-ins and is used for to display image and blanking timing signal S regularly is provided not the pause period that is presented at the frame on the color LCD at image
TM(not shown).
Gamma-correction circuit 6 according to from the gray correction code GC of control circuit 3 feed-ins by to from the outside or the red data D of frame memory 4 feed-ins as digital of digital video data
R, green data D
GWith blue data D
BCarrying out gamma correction provides gray scale, then them as red data D
RG, green data D
GGWith blue data D
BGOutput.
Next, gamma correction will be explained.The reproducing characteristic of image is with the curve representation in the curve chart (for example, the logarithm value of the display brightness of the reproduced image that shows as abscissa and the digital video signal that utilizes video camera to provide with display screen of the logarithm value of the display brightness that had originally with the object such as scene, profile that uses video camera to take draw as ordinate curve chart).When the curve inclination angle of expression reproducing characteristic was defined as " θ ", " tan θ " was called as " gradation of image (γ) ".When the display brightness of object on display in the reproduction of reality, in other words, when the numerical value of abscissa (input) increases progressively 1 and ordinate (output) when also increasing progressively 1, represent the curve of reproducing characteristic to become straight line with 45 ° of inclinations angle, and because Tan θ=1, so gradation of image becomes 1.So, for the gradation of image (γ) of whole system that reproduces the display brightness of object faithfully, comprise the video camera that is used for reference object and be used for the display of reproduced image must be " 1 ".Yet every kind such as CCD (charge coupled cell) that constitutes video camera or the gradation of image that the imaging device the CRT monitor all has it.The gradation of image of CCD is " 1 ", and the gradation of image of CRT monitor is about " 2.2 ".In order to make gamma correction to whole system is " 1 " and in order to obtain the reasonable reproduced image of gray scale, and it is essential that digital of digital video data is proofreaied and correct, and this correction is called as " gamma correction ".In general, gamma correction is carried out digital of digital video data, so that have the data that the gamma characteristic with CRT monitor is complementary.
Fig. 4 represents the characteristic curve (gamma curve) of display brightness (output) to the gray scale (input) of CRT monitor and color LCD 1.In Fig. 4, curve " a " is the gradation of image characteristic curve of CRT monitor, and curve " b " be image when white during a frame period by the gradation of image characteristic curve that obtains when being presented on the color LCD 1 continuously.Hereinafter, still frame is presented at situation on the color LCD 1 and is called as " usual situation about driving ".Curve " c " be for show on the color LCD 1 motion picture the time cycle of display image signals be equivalent in the first half of a frame period the inside 50% and time cycle of showing non-image signal be equivalent to back 50% in half a frame period the inside in and the gradation of image characteristic curve that when the blanking level BL of non-image signal is 127/255, obtains.Blanking level BL is in order to make black display on color LCD 1 and the voltage levvl of regulation, and white level is expressed as 255/255 in normal picture signal, and black level is expressed as 0/255 in normal picture signal.Originally, though blanking level BL is 0/255 ideally,, under the sort of situation, as describing the front, display brightness uprises along with the speed of blanking signal and reduces gradually.Reduce and improve display brightness for fear of display brightness, make blanking level BL than 0/255 height.In this case, black floats, and that is to say, the demonstration of black becomes bright, so the gradation of image characteristic changes.Even blanking is than relying on blanking sign indicating number BC to increase progressively conversely speaking,, in theory, if blanking level BL remains on 0/255, the gradation of image characteristic will not change so.On the other hand, because display brightness successively decreases because of the blanking ratio increases progressively, it is essential that the illumination BB (not shown) of rising back lighting becomes.Yet when the illumination BB of back lighting raise, the power consumption of power supply will increase usually.In addition, when being subjected to the Characteristics Control of back lighting, power exist certain to limit by changing when illumination.If the illumination BB of back lighting only is raised, will not take place in the change aspect the gradation of image characteristic of LCD.Yet in fact, in some cases, the spectral distribution of back lighting is owing to the illumination BB of the back lighting that increases progressively is changed.In this case, in the liquid crystal indicator that Fig. 1 showed, because the gradation of image characteristic of LCD changes, be essential so select suitable gamma correction code GC according to the motion picture parameter such as the illumination BB of blanking sign indicating number BC, blanking level BL and back lighting.In addition, aspect optimal gradation of image characteristic, obviously exist certain difference in plan (for example, between binary picture and the image such as photo) between the pattern that shows on the color LCD 1.Gamma correction code GC is not always only selected according to the illumination BB of blanking sign indicating number BC, blanking level BL or back lighting.Therefore, in embodiments, gamma correction code GC is added on the motion picture parameter.
Therefore, in Fig. 1, control circuit 3 is according to the motion vector data D from motion detection circuit 2 feed-ins
VProduce gamma correction code GC and it is fed to gamma-correction circuit 6 with control signal from the feed-in of display control section (not shown).Here, be to be used for making the characteristic of the image that is shown to be suitable for the signal of observer's preferential selection from the control signal of display control section feed-in.Yet, in Fig. 4, the relative display brightness that display brightness obtains when being expressed as being defined as " 1 " when display brightness shows with the highest gray scale of each demonstration.
As what from Fig. 4, see, even picture is displayed on the identical color LCD 1, in the situation of the usual driving that is showing still frame aspect the gradation of image characteristic with show between the situation of motion picture and exist certain difference.So, gamma-correction circuit 6 according to from the gamma correction code GC of control circuit 3 feed-ins in the situation of the usual driving that shows still frame with show between the situation of motion picture to each red data D
R, green data D
GWith blue data D
BCarrying out different γ proofreaies and correct.Gamma correction code GC is as all red data D
R, green data D
GWith blue data D
BAll be determined is that still frame and having sent is set to " 0 " when being used for showing the instruction of still frame; As all red data D
R, green data D
GWith blue data D
BAll be determined is that motion picture and having sent is set to " 1 " when being used for showing the instruction of motion picture.In addition, in color LCD 1, the performance transmission coefficient t is not linear to the characteristic curve (V-T characteristic curve) of the voltage V that imposes on data electrode, and the ratio of the variation of transmission coefficient and the variation of applied voltage V is little in that black level is arranged near showing the zone that exists.In addition, because the V-T characteristic curve is different in every kind of color of red, green, blue, so the gradation of image characteristic curve is different in every kind of color of red, green, blue.Therefore, gamma-correction circuit 6 is to each red data D
R, green data D
GWith blue data D
BCarry out gamma correction separately, so that their central each can both make the characteristic of the transmission coefficient t of every kind of central color of redness, green and blueness be complementary with the voltage that imposes on data electrode.
Data converting circuit 7 is according to the timing signal S of controlled circuit 3 controls from 5 feed-ins of blanking timing generation circuit
TMAt red data D
RG, green data D
GGWith blue data D
BGAnd change and export the data that are converted between the blanking signal.Here, the blanking signal representative has the signal of black display on color LCD 1, and each red data D
RG, green data D
GGWith blue data D
BGIt all is the magnitude of voltage (that is blanking level BL) that makes the regulation of black display on color LCD 1.
Data electrode driver circuit 8 is according to selecting to use from the red data D of data converting circuit 7 feed-ins from the timing of each control signal of control circuit 3 feed-ins
RG, green data D
GG, blue data D
BGOr the grayscale voltage of blanking signal regulation, and each selected voltage imposed on data electrode corresponding in color LCD 1 as red data signal, green data signal and data blue signal.Scan electrode driving circuit 9 adopts from the timing of control circuit 3 feed-in control signals and produces sweep signal continuously and continuously the signal that is produced is imposed on scan electrode corresponding color LCD 1.
Back lighting 10 makes from the light diffusion of light source by light source and being used for and this light source is used as the light diffusion member that flat-plate light source uses forms, and it illuminates the back side of the color LCD 1 that is not luminescent device itself.The light source of back lighting 10 comprises fluorescent tube, high-pressure discharge lamp, flat florescent lamp, electroluminescent cell, the light-emitting component such as the light-emitting diode of white etc.
Fig. 5 shows 8 fluorescent lamps 12 of use
1To 12
8Diagrammatic top view as the back lighting 10 of light source.As shown in Figure 5, fluorescent lamp 12
1To 12
8In accordance with regulations interval L arranges on accurate scanning direction (being the direction of the row of color LCD 1).Fig. 6 is that all fluorescent lamps 12 are worked as in graphic extension
1To 12
8The illumination of the back lighting 10 that obtains when all being switched on.Inverter 11 glistens in back lighting 10 according to the blanking code BC from control circuit 3 feed-ins.
Next, the operation with liquid crystal indicator of above-mentioned configuration will make an explanation below.At first, gamma correction is at each the red data D that is equivalent to feed-in from the outside in time cycle of 1/4th in frame period
R, green data D
GWith blue data D
BCarry out, and through the data of gamma correction by respectively as red data D
RG, green data D
GGWith blue data D
BGPresent to data electrode driver circuit 8.
Next, the key points for operation of the liquid crystal indicator of first embodiment will be described below.At first, motion detection circuit 2 is from by the red data D as digital of digital video data feed-in from the outside
R, green data D
GWith blue data D
BThe image the inside of forming detects numerous motion vectors.In addition, frame memory 4 stores by the red data D as digital of digital video data
R, green data D
GWith blue data D
BNumerous two field pictures of forming.Then, motion detection circuit 2 extracts the fastest motion vector from numerous detected motion vectors the inside, and it as motion vector data D
VPresent to control circuit 3.This causes that control circuit 3 is according to motion vector data D
VProduce blanking code BC and gamma correction code GC.Here, control circuit 3 is as motion vector data D
VAs in Fig. 3 with waveform " a " show vertiginous the time motion picture parameter after changing the motion picture parameter and export change as the rate of change of in Fig. 3, showing according to being used in several frames predictions of motion vector data before taking place to change fast with waveform " b ".Then, control circuit 3 blanking sign indicating number BC present to blanking timing generation circuit 5 and inverter 11 both, simultaneously gamma correction code GC is presented to gamma-correction circuit 6.In addition, control circuit 3 is according to horizontal-drive signal SH, vertical synchronizing signal SV or similar thing control data change-over circuit 7, data electrode driver circuit 8 and scan electrode driving circuit 9.So, because blanking timing generation circuit 5 produces timing signal STM according to the blanking sign indicating number BC from control circuit 3 feed-ins and it is presented to data converting circuit 7.In addition, gamma-correction circuit 6 according to gamma correction code GC to as digital of digital video data from the outside or from the red data D of frame memory 4 feed-ins
R, green data D
GWith blue data D
BCarry out gamma correction so that provide gray scale to them, then them as red data D
RG, green data D
GGWith blue data D
BGOutput.Controlled circuit 3 controls of data converting circuit 7 and according to the timing signal S that regularly produces circuit 5 feed-ins from blanking
TMAt each red data D from gamma-correction circuit 6 feed-ins
RG, green data D
GGWith blue data D
BGAnd change and export data after the conversion between the blanking signal.So data electrode driver circuit 8 adopts from the timing of each control signal of control circuit 3 feed-ins and selects by means of the red data D from data converting circuit 7 feed-ins
RG, green data D
GGWith blue data D
BGThe grayscale voltage of regulation and each selected voltage imposed on data electrode corresponding in the color LCD 1 as red data signal, green data signal and data blue signal.In addition, scan electrode driving circuit 9 adopts from the timing of control circuit 3 feed-in control signals and produces sweep signal continuously and continuously the signal that generates is imposed on scan electrode corresponding the color LCD 1.Simultaneously, inverter 11 makes eight fluorescent lamps (12 forming back lighting 10 according to the blanking sign indicating number BC from control circuit 3 feed-ins
1To 12
8) flash of light.
This makes the high-quality colour image of being made up of motion picture and still frame to be presented on the color LCD 1 under the situation that reduces power consumption.
Next, describe the power consumption that reduces back lighting 10 in detail.In this embodiment, in order to reduce the power consumption of back lighting 10, take standard of measurement (measure) A and standard of measurement B.As standard of measurement A, eight all fluorescent lamps 12 of showing among Fig. 5
1To 12
8Flash of light simultaneously.As standard of measurement B, eight fluorescent lamps 12 showing among Fig. 5
1To 12
8Scanning according to scan electrode corresponding in color LCD 1 is glistened successively.
(1) under the situation of standard of measurement A:
Fig. 7 to 11 is illustrated in the sweep signal Y that presents in the color LCD 1 to 768 scan electrodes
1To Y
768Waveform and the backlight illumination signal S that when adopting standard of measurement A, obtains
LWaveform.Sweep signal Y in Fig. 7 to 11 displaying
1To Y
768In, P
DBe to make to be connected on the whole conductings of TFT on the corresponding scan electrode and to reach the image of in the liquid crystal cells that driven by TFT, writing the high potential of picture signal to write pulse.Similarly, the sweep signal Y that in Fig. 7 to 11, shows
1To Y
768In, P
BBe to make to be connected on the whole conductings of TFT on the corresponding scan electrode and to reach the blanking of in the liquid crystal cells that driven by TFT, writing the high potential of blanking signal to write pulse.
Fig. 7 shows that blanking sign indicating number BC is " 0 ", and promptly blanking is than the situation that is 0%.In Fig. 7, because the blanking ratio is 0%, so at each sweep signal Y
1To Y
768The inside regularly departs from being equivalent to image and writing pulse P
DTime cycle.In addition, shown in Fig. 7 (7), back lighting control signal S
LBe high potential at any time, that is to say, eight all fluorescent lamps 12
1To 12
8In a complete frame period, all connect and light.In addition, arrive each the sweep signal Y that shows in (6) at Fig. 7 (1)
1To Y
768All be added on the corresponding scan electrode by each image duration in odd-numbered and sequence even-numbered in the same way.Fig. 8 and Fig. 9 show some examples, and blanking sign indicating number BC is " 10 " in these examples, that is to say, the blanking ratio is 25%.Arrive the sweep signal Y that shows in (6) at Fig. 8 (1)
1To Y
768When being in the sequence of odd-numbered, frame is added on the corresponding scan electrode, and at the sweep signal Y of Fig. 9 (1) displaying in (6)
1To Y
768When being in the sequence of even-numbered, frame is added on the corresponding scan electrode.Conspicuous as in Fig. 8, going up from (1) and (2) and (5) and (6), be present in each the sweep signal Y in the sequence of odd-numbered
2n-1With the sweep signal Y in the at the heel sequence that is present in even-numbered
2n(n is a natural number) has same waveform.On the other hand, be present in each sweep signal Y in the sequence of even-numbered
2nWith the sweep signal Y in the at the heel sequence that is present in odd-numbered
2n(n is a natural number) has same waveform.In other words, in this embodiment, the image duration in the sequence of odd-numbered is by scanning the sweep signal Y in the sequence that is present in odd-numbered simultaneously
2n-1With the sweep signal Y in the sequence that is present in even-numbered
2nBoth, identical signal is transferred to the TFT of corresponding pixel simultaneously.So, when comparing, scan the needed time can be reduced to half with the situation that delegation is scanned.Yet if use this display packing like this, because the main scanning line density that is used to show is reduced to half, display resolution is lowered.This display packing often is used when so employed interleaved signal of NTSC system is presented on the LCD.With regard to regard to the picture signal of using in such NTSC system, effectively the number of main scanning line is about 480, and a frame is made up of two fields, and first field is only to be made up of the odd lines signal, and second field is only to be made up of the even lines signal.Each odd-numbered frame and even frame correspond respectively to each the first above-mentioned field and second field.On the other hand, in this embodiment, because the number by the longitudinal direction pixel is 768 in color LCD 1, so in order to be presented at the picture signal of using in the NTSC system, it is essential changing aspect scan line.
Yet, when the number of pixel is 480 by longitudinal direction on color LCD when, in fact picture signal in first field of the picture signal of using in the NTSC system can show during odd-numbered frame, and in fact the picture signal in second field of the picture signal of using in the NTSC system can show during even frame.Otherwise, when data are presented on the color LCD, by " sparse " picture signal simply and at any time scanning simultaneously be present in sweep signal Y in the odd number sequence
2n-1With the at the heel sweep signal Y that is present in the even number sequence
2n, under the situation of not distinguishing odd-numbered frame or even frame, same signal can be transferred to the TFT of each corresponding pixel simultaneously by two lines.Yet display resolution is reduced to half.
By using above-mentioned driving method, even display brightness does not use the sort of yet obtainable display brightness of scan method that doubles used in second conventional example no better than.So in above-mentioned embodiment, color LCD 1, data electrode driver circuit 8 and scan electrode driving circuit 9 can be for simpler and dispose.In Fig. 8 and Fig. 9,, be used for writing image and write pulse P because the blanking ratio is 25%
DTiming at each sweep signal Y
1To Y
768In all be slightly offset, and be used for blanking pulse P
BTiming write pulse P at two images
DBetween depart from 3/4ths the time cycle that equals a frame a little.In addition, shown in Fig. 8 (7) and Fig. 9 (7), back lighting control signal S
LAll the time be high level, eight promptly all fluorescent lamps 12
1To 12
8During whole frame periods, all be switched on and light.
Figure 10 shows an example, and blanking sign indicating number BC is " 20 " in this example, i.e. blanking ratio is 59%, and arrives the sweep signal Y that shows in (6) at Figure 10 (1)
1To Y
768When being in the odd number sequence, frame is applied in.Conspicuous as in Fig. 8, going up from (1) and (2) and (5) and (6), be present in the sweep signal Y in the odd number sequence
2n-1With immediately following the sweep signal Y that is present in thereafter in the even number sequence
2n(n is a natural number) has identical waveform.In addition, though the situation that frame is present in the even number sequence does not show that timing is different from the situation of showing in Fig. 9, and is present in the sweep signal Y in the even number sequence
2n-1With immediately following the sweep signal Y that is present in thereafter in the odd number sequence
2n(n is a natural number) has identical waveform.In Figure 10,, write pulse P so be used for writing image because the blanking ratio is 50%
DTiming at each sweep signal Y
1To Y
768In all be slightly offset, and be used for blanking pulse P
BTiming write pulse P at two images
DBetween depart from half the time cycle that equals a frame.In addition, shown in Figure 10 (1) and 10 (6), during the time cycle after being present in for 3/4ths in the frame period, has only blanking pulse P
BAt each sweep signal Y
1To Y
768Middle generation and blanking show on all scan lines.So, as that in Figure 10 (7), shows, back lighting control signal S
LBe present in a frame period 3/4ths after time cycle in become electronegative potential, in other words, be present in a frame period during the time cycle after 3/4ths eight all fluorescent lamps 12
1To 12
8All be switched off.
In Figure 11, be under the situation of " 30 " at blanking sign indicating number BC, promptly in blanking than being under 75% the situation, at the sweep signal Y of Figure 11 (1) displaying in (6)
1To Y
768When being in the odd number sequence, frame is fed.In Figure 11, shown in Figure 11 (1) and (2) and Figure 11 (5) and 11 (6), be present in the sweep signal Y in the odd number sequence
2n-1With immediately following the sweep signal that is present in thereafter in the even number sequence
2n(n is a natural number) has identical waveform.In addition, do not show, regularly only be different from the situation of in Fig. 9, showing, and each is present in the sweep signal Y in the even number sequence though be present in the situation of the frame in the even number sequence
2nWith immediately following the sweep signal Y that is present in thereafter in the odd number sequence
2n+1(n is a natural number) has identical waveform.
In Figure 11,, be used for writing image and write pulse P because the blanking ratio is 75%
DTiming at each sweep signal Y
1To Y
768All be slightly offset, and be used for blanking pulse P
BTiming writing pulse P at two images
DBetween depart from the time cycle that equals 1/4th frames a little.In addition, shown in Figure 11 (1) and 11 (6), in a frame period, exist in the time cycle of half, have only blanking pulse P
BAt each sweep signal Y
1To Y
768The middle generation, and blanking shows on all scan lines.So, as that in Figure 11 (7), shows, back lighting control signal S
LIn time cycle after being present in a frame period half all is electronegative potential, that is to say, be present in the frame period half after time cycle in, eight all fluorescent lamps 12
1To 12
8All be switched off.
Next,, double in second conventional example of scan method in use in order to compare, when blanking when being 0%, 25%, 50% and 75%, each sweep signal Y
1To Y
384Waveform be illustrated among Figure 12 to Figure 15.At Figure 12 to sweep signal Y that Figure 15 showed
1To Y
384In, P
DRepresent that above-mentioned image writes pulse, and P
BIt is above-mentioned blanking pulse.Double scan method and represent a kind of method, each picture signal wherein is all by scanning the TFT that is transferred to every corresponding each corresponding image of scan line simultaneously on eight scan lines.When in Figure 12 to 15, show double scan method and be used in, sweep signal Y
1With sweep signal Y
192Scanned simultaneously, then sweep signal Y
2To sweep signal Y
194Scanned last sweep signal Y successively simultaneously
193With sweep signal Y
384Scanned simultaneously, and the scan operation in a frame finishes.Therefore, in doubling scan method, in order to shift and two corresponding picture signals of scan line simultaneously, the circuit scale of data electrode driver circuit 8 is doubled.Yet in doubling scan method, the scanning time necessary can be reduced to half under the situation that does not reduce main scanning resolution.
In Figure 12, if blanking sign indicating number BC is " 0 ", that is to say, if the blanking ratio is " 0% ", so at each sweep signal Y
1To Y
768In, have only image to write pulse P
DTiming departed from the time cycle that equals 1/4th frames a little.Figure 13 shows that blanking sign indicating number BC is the situation of " 10 ", that is to say that blanking is than the situation that is 25%.In Figure 13, because the blanking ratio is 25%, at each sweep signal Y
1To Y
768In be used for writing image and write pulse P
DTiming all depart from 1/4th the time cycle that equals a frame period a little, and write pulse P at two images
DBetween be used for blanking pulse P
BTiming departed from 3/4ths the time cycle that equals a frame a little.
Figure 14 shows that blanking sign indicating number BC is " 20 ", and promptly blanking is than the situation that is 50%.In Figure 14, because the blanking ratio is 50%, at each sweep signal Y
1To Y
768In be used for writing image and write pulse P
DTiming departed from 1/4th the time cycle that equals a frame period a little, and write pulse P at two images
DBetween be used for blanking pulse P
BTiming departed from half the time cycle that equals a frame a little.In Figure 15,, that is to say that the blanking ratio is 75%, at each sweep signal Y because blanking sign indicating number BC is 30
1To Y
768In be used for writing image and write pulse P
DTiming departed from 1/4th the time cycle that equals a frame period a little, and write pulse P at two images
DBetween be used for blanking pulse P
BTiming departed from 1/4th the time cycle that equals a frame a little.In addition, the result who compares in above-mentioned standard of measurement A and second conventional example will be described after a while.
(2) under the situation of standard of measurement B:
In Figure 16 to 19, the back lighting control signal S that when adopting standard of measurement B, obtains
L1To S
L8Waveform and sweep signal Y
1To Y
768768 waveforms on color LCD 1 are demonstrated out.At Figure 16 to each sweep signal Y that Figure 19 showed
1To Y
768In, BC is " 0 " when the blanking sign indicating number, that is to say, when the blanking ratio is " 0% ".In Figure 16 because the blanking ratio is 0%, as at Figure 16 (9) to shown in 16 (11), at each sweep signal Y
1To Y
768In, image writes pulse P
DTiming only departed from a little.In addition, as that shows in to 16 (8), back lighting control signal S at Figure 16 (1)
L1To S
L8All the time be high level, that is to say, eight fluorescent lamps 12 in a complete frame period
1To 12
8All be switched on and light.
In Figure 17, BC is " 10 " when the blanking sign indicating number, that is to say, blanking is when being 25%.In Figure 11, because the blanking ratio is 25%, as shown in figure 17, at each sweep signal Y
1To Y
768In, image writes pulse P
DTiming departed from a little, and write pulse P at two images
DBetween be used for blanking pulse P
BTiming departed from 3/4ths the time cycle that equals a frame a little.In addition, as Figure 17 (1) to shown in 17 (8), though back lighting control signal S
L1To S
L8Timing be slightly offset and become low level, but do not have signal to become low level simultaneously.This makes eight fluorescent lamps 12
1To 12
8In the middle of always have one during a frame period, to light.
In Figure 18, blanking sign indicating number BC is " 20 ", that is to say, the blanking ratio is 50%.In Figure 18, because the blanking ratio is 50%, at each sweep signal Y
1To Y
768In, as at Figure 18 (9) to shown in 18 (11), image writes pulse P
DTiming departed from a little, and write pulse P at two images
BBetween be used for blanking pulse P
BTiming depart from half the time cycle that equals a frame a little.As Figure 18 (1) to shown in 18 (8), each back lighting control signal S
1To S
8Depart from a little and only a frame period 1/4th during become low level.
Figure 19 shows that blanking sign indicating number BC is the situation of " 30 ", that is to say, when the situation of blanking when being 75%.In Figure 19 because the blanking ratio is 75%, as Figure 18 (9) to shown in 18 (11), at each sweep signal Y
1To Y
768In, image writes pulse P
DTiming be slightly offset, and write pulse P at two images
BBetween be used for blanking pulse P
BTiming depart from 1/4th the time cycle that equals a frame a little.As that shows in to 19 (8), each back lighting control signal S at Figure 19 (1)
L1To S
L8All be slightly offset and only during half of a frame period, become low level.
Next, at blanking sign indicating number BC and blanking than the display brightness of Coefficient of Utilitization (lighting rate), power consumption and back lighting 10 relatively between standard of measurement A in second conventional example and the standard of measurement B.
Figure 20 is the chart that represents from according to the result of the comparison of the first embodiment back lighting 10 between standard of measurement A and standard of measurement B.As conspicuous, under the situation of standard of measurement A, because eight fluorescent lamps 12 from Figure 20
1To 12
8Be synchroflash, so the peak value of Coefficient of Utilitization remains unchanged.Otherwise, under the situation of standard of measurement B, because eight fluorescent lamps 12
1To 12
8Glisten in order,, depend on the blanking ratio so the peak value of Coefficient of Utilitization changes.In addition, under standard of measurement A and two kinds of situations of standard of measurement B, the mean value of Coefficient of Utilitization changes, and depends on the blanking ratio.
In Figure 21, provide when the illumination of fluorescent lamp the power consumption that occurs in when controlled like this so that display brightness is equal to each other in the back lighting 10 in standard of measurement A and standard of measurement B and in traditional example.In Figure 21, if the blanking ratio is 0%, power consumption all equates in every kind of situation so, and it is 100%.In second above-mentioned conventional example, if the blanking ratio is " a " %, power consumption is { 100/ (100-a) } % so, (a>0).As conspicuous from Figure 21, between the situation of second conventional example, standard of measurement A and standard of measurement B difference not taking place though be engraved in aspect the power consumption, occurs between second conventional example, standard of measurement A and the standard of measurement B in significant difference aspect the average power consumption when peak value.This is because following reason.In other words, when blanking than becoming than higher the time, for keep with in blanking than being identical display brightness in 0% the situation, if do not take measures, the power consumption of back lighting 10 will increase gradually so.As in the situation of standard of measurement A, by blanking pulse P
BImpose on all scan electrodes and by turning off back lighting 10, though peak value constantly power consumption remain unchanged, the illumination of working as back lighting 10 becomes useless the time, if back lighting 10 is lighted, average power consumption can be reduced so.On the other hand, in the situation of standard of measurement B, because eight fluorescent lamps 12
1To 12
8According to blanking than flash of light in succession, so reduce back lighting 10 peak value constantly power consumption and average power consumption the two be possible.In addition, in Figure 21, the representative of parenthetic numerical value is when the brightness of back lighting 10 does not change and peak value power consumption constantly obtains when being maintained at 100% all the time display brightness.
Figure 22 show when power consumption and display brightness all be 100% brightness that occurs in blanking when being 0% and work as back lighting 10 from only 100% rising to peaked 133% and between second conventional example, standard of measurement A and standard of measurement B, obtain, that is to say, the comparative result of the power consumption that when the power consumption in the peak value moment can not rise to 133%, between second conventional example, standard of measurement A and standard of measurement B, obtains and the speed of display brightness when being impossible than what could obtain when being 0% in blanking.In addition, Figure 23 show illustrate for keep according to first embodiment of the present invention when display brightness be when blanking sign indicating number BC is " 0 ", obtain 100% in the curve chart of the necessary power consumption of display brightness that obtains.In other words, Figure 23 shows the curve chart that the power consumption of showing among Figure 21 is drawn as curve.In Figure 23, curve " a " is showed the state that obtains under the situation of second conventional example and standard of measurement A when power consumption is in its peak level, and curve " b " show when power consumption the average level that is in it under the situation of standard of measurement A and under the situation of standard of measurement B, be in it peak level and its average level in the state that obtains.
If Figure 24 is that to illustrate according to first embodiment of the present invention can enough blanking sign indicating number BC be that " 0 " is the curve chart of the display brightness kept of 100% power consumption so.In other words, Figure 24 shows the numerical value that is drawn as the curve acquisition by the display brightness that Figure 21 is showed.In Figure 24, curve " a " is showed the state that obtains when power consumption in the peak level that is in it under the situation of second conventional example and standard of measurement A, and curve " b " show when display brightness in the average level that is in it under the situation of standard of measurement A and the state of acquisition when under the situation of standard of measurement A, being in its peak value and being in its average level.Figure 25 be show display brightness and be used for keeping when power consumption and display brightness all be 100% when occurring in blanking code BC and be " 0 " and when the brightness of back lighting 10 might from blanking than can obtain when being 0% 100% be elevated in peaked 133%, promptly when the curve chart of power consumption necessary power consumption of display brightness of acquisition when the peak value moment only can be elevated to 133%.In other words, Figure 25 shows by the display brightness of showing among Figure 22 being drawn as the numerical value that curve obtains.In Figure 25, curve " a " is showed when power consumption and is being in its peak level and is being in the state that obtains in its average level under second conventional example and situation standard of measurement A and under second conventional example and situation standard of measurement B; Curve " b " is showed when display brightness be in the state that obtains in its peak level under second conventional example and situation standard of measurement A; And curve " c " show when display brightness in the average level that is in it under the situation of standard of measurement A and under the situation of standard of measurement B, be in its peak level and be in the state that obtains in its average level.
Therefore, according to first embodiment, blanking timing generation circuit 5, gamma-correction circuit 6 and inverter 11 all are that basis is from numerous motion vector data D that extract in the detected motion vector image
VControlled.So according to the configuration of this embodiment, flicker takes place, both do not had the trace phenomenon not have image retention to take place yet, even and blanking is provided, the power consumption of back lighting 10 also can reduce.This makes and is fit to provide the power circuit of power to dispose so small and exquisitely with low price.
Next, explain the particular instance of power consumption in back lighting 10.When color LCD 1 be above-mentioned WXGA type and also display brightness be set to when driving normally 500[cd/m
2] time and when the display pattern that be called " grid mark (checker flag) " is presented on the color LCD with the display brightness of maximum, the power consumption of back lighting 10 is about 12 watts.Here, grid mark representative has the display pattern that identical shaped white square and black squares are alternately arranged.As shown in figure 12, about 12 watts power consumption is relying on standard of measurement A to realize under the situation of mean value and is relying on standard of measurement B to realize being reduced under the situation of peak value and mean value only about half of.
Second embodiment
Figure 26 shows the block diagram that uses according to second embodiment of the present invention configuration of the liquid crystal indicator of the method for display image on LCD.
This liquid crystal indicator comprises LCD21, motion detection circuit 22, video processing circuits 23, graphic processing circuit 24, storage circuit 25, multiwindow control circuit 26, display control circuit 27 and bus 28.Motion detection circuit 22, video processing circuits 23, graphic processing circuit 24, storage circuit 25, multiwindow control circuit 26, display control circuit 27 are joined to one another by bus 28.In addition, the back lighting (not shown) is connected all the time.
As shown in figure 27, LCD 21 has the resolution of 1080 row * 1920 pixels, and display resolution is that the window 31 and the resolution of 810 row * 1440 pixels are the window 32 of 850 row * 1400 pixels on this display screen.Hereinafter, the entire display screen of LCD 21 is called " window 30 ".
22 pairs of motion detection circuits are by outside feed-in and not compressed as yet digital of digital video data D
PEach screen of forming detects numerous motion vectors, and extracts the fastest motion vector from described numerous motion vectors.In addition, motion detection circuit 22 is set motion picture parameter MP according to the fastest motion vector that extracts
1And it is transferred to display control circuit 27 by bus 28.In this embodiment, motion picture parameter MP
1Be to set like this, so that it is corresponding to 0% to 75% blanking rate.Under the situation of rest image, the blanking rate is 0%.In addition, with regard to the configuration and operation of the method that detects motion vector and testing circuit, please refer to Japanese Patent Application Publication Hei 9-93585 and Hei 9-212650 number.In addition, motion detection circuit 22 passes through bus 28 digital of digital video data D
PBe sent to storage circuit 25.
23 pairs of video processing circuitss are by outside feed-in and not compressed as yet digital of digital video data D
CPEach screen of forming detects numerous motion vectors, and extracts the fastest motion vector.In addition, video processing circuits 23 is set motion picture parameter MP according to the fastest motion vector that is extracted
2And it is transferred to display control circuit 27 by bus 28.In this embodiment, motion picture parameter MP
2Be to set like this, so that it is corresponding to 0 to 75% blanking rate.Under the situation of rest image, the blanking ratio is 0%.In addition, video processing circuits 23 is digital of digital video data D
CPExtend to digital of digital video data D
EPAnd the digital of digital video data D that obtains by expansion
EPTransfer to storage circuit 25 through bus 28.
Video processing circuits 23 is digital of digital video data D
CPBe expanded into digital of digital video data D
EPThe time finish the processing that reduces resolution according to the storage volume of congestion state during transferring data and storage circuit 25 in bus 28.Here, the processing representative that reduces resolution reduces digital of digital video data D
EPThe processing of data volume.
The image of graphic processing circuit 24 basis feed-ins from the outside writes instruction CMD and image writes data D
PPProduce still image data D
SPAnd pass through bus 28 still image data D
SPTransfer to storage circuit 25.Storage circuit 25 is to be made of the video memory such as RAM (random access memory), and stores the digital of digital video data D that is transferred to the appointed area by bus 28
P, digital of digital video data D
EPWith still image data D
SP
26 management of multiwindow control circuit are used for demonstration, information and the above-mentioned motion picture parameter of whole windows, so that be presented at on the LCD 21 that shows among Figure 27.In addition, multiwindow control circuit 26 is presented the maximum access speed " α " of storage circuit 25 and memory capacity X and about the information (for example, " displaying contents type T " or " priority P ") of window 30 to 32." displaying contents type T " is fed to discern it and prepares mainly type with form content displayed in window 30 to 32 of data." displaying contents type T " is " 1 " for graph data, and is " 2 " for video data." priority P " is provided in addition, is in order to point out its " front and back " relation in the presence of all when windows display shows on LCD 21.For example, if the value of priority P is 1, it points out that this window is positioned at top position so.Then, the value increase along with priority P for example, is increased to " 3 " from " 2 ", and it points out that window is positioned at the back in order.Figure 28 is the chart that illustrates with an example of the information of each window 30~32 that is subjected to multiwindow control circuit management according to second embodiment of the present invention and motion picture relating to parameters.As Figure 28 and shown in Figure 29, window size, the window's position, displaying contents type, priority P and motion picture parameter are all managed by window number.The content of showing in Figure 29 is described after a while.
The demonstration of each window is finished in the instruction that display control circuit 27 sends according to multiwindow control circuit 26.In other words, display control circuit 27 is at first the digital of digital video data D that will show on each window
P, digital of digital video data D
EPWith still image data D
SPFrom storage circuit 25, read.Then, display control circuit 27 so that be used for showing the numerical data D that each is above-mentioned
P, digital of digital video data D
EPWith still image data D
SPThe digital of digital video data D of mode that be complementary of the size of window to being read out
P, digital of digital video data D
EPWith still image data D
SPFinish reduction and handle (that is, " rarefaction " handled) or expand processing (that is, interpolation is handled), and be presented on the LCD 21.For example, if digital of digital video data D
SPBe to be stored by " rarefaction (that is, reduction) " state to half in the vertical with it in storage circuit 25, display control circuit 27 is having by vertically from digital of digital video data D so
EPIn shown it at corresponding window after the sparse interpolative data that falls.At this moment, motion detection circuit 22 is based on the motion picture parameter MP from motion detection circuit 22 and video processing circuits 23 feed-ins
1And MP
2, finish reduction and expand processing, and produce demonstration motion picture parameter PM, so that in each window, cause level and smooth change.Adjusting is performed such, so that the motion of object becomes and follows the tracks of (that is, showing the variation of motion picture parameter) than faster the time and also become than comparatively fast in the image; Follow the tracks of when the motion of object becomes slow (that is, by the control that lags behind) in image and also become slow.Why use the reasons are as follows of the control that lags behind at this.In general, variation when the people is not converted into motion picture to still frame produces reaction, yet the variation the when people is converted into still frame to motion picture produces reaction.
Next the configuration of image processing circuit 23 is described.Figure 30 is the block diagram of graphic extension according to the configuration of the video processing circuits 23 of second embodiment of the present invention.The video processing circuits 23 of this embodiment comprises decoding treatment circuit 41, timer 42 and low resolution treatment circuit 43.
Decoding treatment circuit 41 is from forming the compressed digital video data D of feed-in from the outside
CPEvery screen in detect numerous motion vectors and from numerous motion vectors, extract the fastest vector.In addition, decoding treatment circuit 41 is set motion picture parameter MP according to the fastest motion vector that extracts
2And it is transferred to display control circuit 27 by bus 28.
In addition, decoding treatment circuit 41 is the digital of digital video data D of feed-in
CPBe expanded into digital of digital video data D
EPAnd the digital of digital video data D that obtains from expansion
EPTransfer to storage circuit 25 by bus 28.Decoding treatment circuit 41 is digital of digital video data D
CPBe expanded into digital of digital video data D
EPIn time, handle according to finishing " rarefaction " from the instruction of low resolution treatment circuit 43.The instruction that decoding processing circuit 41 is accepted from low resolution treatment circuit 43, for example, with the form of " k=1/2 ".This makes decoding treatment circuit 41 finish " rarefaction " and handles, so that when finishing expansion data are reduced to half.Above-mentioned symbol " k " expression " rarefaction " coefficient, this coefficient are pointed out to represent by " rarefaction " and are handled the amount of the digital of digital video data that obtains and pass through to expand compressed digital of digital video data D under the situation of not carrying out " rarefaction " processing
CPThe digital of digital video data D that obtains
CPThe coefficient of speed of amount.So it is the numerical value of rarefaction coefficient " k " is more little, just many more by the sparse digital of digital video data that falls.Figure 29 A and 29B show the instantiation of " rarefaction " processing that decoding treatment circuit 41 is finished.In Figure 29 A and 29B, the numbering of row number expression row, the numbering of pixel number expression row.Figure 29 A shows that resolution is that to be become resolution by rarefaction be the situation of the pixel block of 4 pixels * 8 row for the pixel block of 8 pixels * 8 row.In this case, decoding treatment circuit 41 utilizes from the rarefaction coefficient " k " (=1/2) of low resolution treatment circuit 43 feed-ins and finishes rarefaction at each row.On the other hand, Figure 29 B shows that the pixel block of 8 pixels * 8 row is by the sparse situation that changes into the pixel block of 4 pixels * 4 row.In this case, decoding treatment circuit 41 utilizes from the rarefaction coefficient " k " (=1/4) of low resolution treatment circuit 43 feed-ins and lists and finish rarefaction at each row simultaneously at each.
Timer 42 has the function of Measuring Time, and the passage of the time of low resolution treatment circuit 43 is just notified in every passage one second.Low resolution treatment circuit 43 inside have the storage low resolution to handle the memory 44 of needed information.Low resolution treatment circuit 43 obtains necessary information and judges whether low resolution is handled is essential from multiwindow control circuit 26, graphic processing circuit 24 and decoding treatment circuit 41, sends command request requisite the time and deciphers treatment circuit 41 and finish " rarefaction processing " when judging that low resolution is handled.Low resolution treatment circuit 43 according to the priority P of each window, will be in window the type etc. of content displayed judge whether low resolution is handled is essential.If the priority P of window 31 is " 2 ", and window 31 is positioned at the back of window 32, and low resolution treatment circuit 43 just judges that it is essential that low resolution is handled.
Next will describe the configuration of display control circuit 27 in detail.Figure 31 is the block diagram of configuration of showing the display control circuit 27 of this embodiment.The display control circuit 27 of this embodiment comprises demonstration motion picture parameter generation circuit 51, gamma-correction circuit 52, frame memory 53, control circuit 54, data electrode driver circuit 55 and scan electrode driving circuit 56.
Show that motion picture parameter generation circuit 51 is according to the motion picture parameter MP from motion detection circuit 22 and video processing circuits 23 feed-ins
1And MP
2Produce demonstration motion picture parameter PM, so that level and smooth variation occurs in each window.Here, Figure 32 shows motion picture parameter MP
1And MP
2And the example that shows the relation between the motion picture parameter PM.In Figure 32, waveform " a " expression motion picture parameter MP
1And MP
2, waveform " b " expression motion picture parameter PM.In the example that Figure 32 showed, show the speed of the following motion picture parameter MP of motion picture parameter PM
1Rise to MP
2The speed of following be set to than showing motion picture parameter PM accompany movement frame parameter MP
1And MP
2The speed of following of decline big four times.
Gamma-correction circuit 52 bases are from the demonstration motion picture parameter MP of demonstration motion picture parameter generation circuit 51 feed-ins, by the digital of digital video data D to all reading from storage circuit 25 as digital of digital video data
1, digital of digital video data D
EPWith still image data D
SPCarrying out gamma correction provides gray scale, then them as view data D
GPOutput.That frame memory 53 is made up of the semiconductor memory such as RAM and be controlled circuit 54 controls, it is storing the numerous frame image data D from gamma-correction circuit 52 feed-ins
GP
Control circuit 54 is made up of ASIC, and its is according to the synchronizing signal S of feed-in from the outside
SYCControl view data D
GPTo the storage of frame memory 53, and according to demonstration motion picture parameter PM view data D that reads from frame memory 53 from 51 feed-ins of demonstration motion picture parameter generation circuit
GPOr blanking signal is transferred to data electrode driver circuit 55.In addition, control circuit 54 is according to synchronizing signal S
SYCOr demonstration motion picture parameter PM control data electrode drive circuit 55 and scan electrode driving circuit 56.In other words, as shown in figure 33, control circuit 54 all writes the sweep signal Y that pulse P forms to each and every one by four images
1To Y
768Be added on the scan electrode, so that identical data-signal was added on the data electrode by four times during a frame period.This is because of being different in blanking in the middle of the delegation than in each pixel.Therefore, briefly, have only the blanking of four types can set than (comprising 0%, 25%, 50% and 75%).Yet in order to improve the quality of image, shown in figure 32, control must be to cause to show that motion picture parameter PM changes smoothly, and consistent with this variation, as shown in figure 34, changes relative brightness smoothly and is absolutely necessary.Then, as shown in figure 35, demonstration applies control to control circuit 54 to image by changing each parameter.In other words, as shown in figure 33, so long as in a frame period, write pulse P by four images each and every one all being
DThe sweep signal Y that forms
1To Y
768Be added on the scan electrode, just only comprise that four blankings of 0%, 25%, 50% and 75% can be set than type.So relative brightness is shown in the relative brightness that obtains before the multiplying as shown in figure 35, and only comprises that four type relative brightnesses of 100%, 75%, 50% and 25% can obtain.Then, control circuit 54 passes through view data D
GPMultiply by multiplication coefficient shown in Figure 35 and by only utilizing view data D
GPAdjust brightness and apply control like this, so that final relative brightness changes as the ground of showing in 34.In addition, if view data D
GPBe Still image data D
SP, so, picture signal (rather than blanking signal) is added on the data electrode.Data electrode driver circuit 55 is used from the used timing of the various types of control signals of control circuit 54 feed-ins and is selected by the view data D from control circuit 54 feed-ins
GPOr the grayscale voltage of blanking signal regulation and selected grayscale voltage is added in LCD21 on the corresponding data electrode as data-signal.Scan electrode driving circuit 56 produces sweep signal continuously according to the timing from control circuit 54 feed-in control signals and continuously the signal that produces is presented to corresponding scan electrode among LCD 21.
Therefore, configuration according to second embodiment, when multiwindow showed in LCD 21, if the type of the displaying contents of view data to be shown is different in each window, it was possible that the demonstration motion picture parameter PM that is used for each window is applied control.So, in this case, acquisition be high-quality image.At this moment, blanking can be set in discontinuous mode than only, comprises 0%, 25%, 50% and 75%.Yet, show that motion picture parameter PM can be set smoothly.Figure 37 shows that configuration is different from those the example of showing of LCD 21 in Figure 27.Figure 37 shows the screen of LCD 21, and as the screen of showing in Figure 27, has the resolution of 1080 row * 1920 pixels.Yet the window of showing among Figure 37 is different from the window of showing in Figure 27, and this window comprises that resolution is that window 61, the resolution of 480 row * 640 pixels are the window 62 of 360 row * 480 pixels and as the window 60 of entire display screen.Outside these three windows, might have the window of numerous demonstration motion pictures, and each window is not shared identical scan line in the middle of the numerous windows that show motion picture.In other words, for example, when motion picture was presented in window 61 and the window 62, as shown in figure 37, window 61 was not shared identical scan line with window 62.In this case, motion picture can not be displayed on the window 60.Otherwise when motion picture was presented in the window 60, it was impossible that motion picture is presented in window 61 and 62.Therefore, rely on to form the above-mentioned window and the demonstration of controlled motion picture, use standard of measurement A that provides in the first embodiment or the motion picture display packing of standard of measurement B can be used.This makes the power consumption of back lighting to be reduced.In addition, by changing the blanking ratio continuously, high-quality image can obtain.
Obviously the present invention is not limited to above-mentioned embodiment, but can be changed and revise under situation about not departing from the scope of the present invention with spirit.For example, in the first above-mentioned embodiment, motion vector is to detect from the whole screen of LCD1 in the example that is demonstrated, yet, shown in 36 figure, the place of detecting motion vector can be limited in the core " b " of the whole screen " a " of LCD 1.
In addition, in the first above-mentioned embodiment, kinematic parameter is according to motion vector data D in the example that is demonstrated
VSet, yet the motion picture parameter can be according to motion vector data D
VSize set.
In addition, in the first above-mentioned embodiment, the blanking of back lighting 10 ratio and Coefficient of Utilitization both are according to motion vector data D in the example that is demonstrated
VChange, yet it also is possible only changing one of them.
In addition, in the first above-mentioned embodiment, eight fluorescent lamps 12 have been installed in the example that is demonstrated
1To 12
8Yet,, the fluorescent lamp of any number all may be used.In addition, light source is not limited to fluorescent lamp, and various dissimilar light source all may be used.
In addition, in each above-mentioned embodiment, motion vector detects from digital of digital video data in the example that is demonstrated.Yet, for example, if the numerical data of feed-in from the outside be compression or with MPEG (Motion Picture Experts Group) 1, MPEG2 or mpeg 3 coding, owing in motion vector has been included in, this motion vector can be used.This makes the detection of omitting motion vector become possibility, and feasible in real time motion picture being presented at becomes possibility on the LCD.
In addition, in each embodiment, on the part of switching between motion picture and the still frame, do not apply control, yet, control can apply like this, so that motion picture parameter in accordance with regulations gradient in the part that display brightness changes changes.In addition, control may apply like this, so that the motion picture parameter is according to motion vector data D
VSize variation.Can provide high-quality image like this.
In addition, in the second above-mentioned embodiment and in the example that Figure 35 showed, show motion picture parameter PM by setting every 5%, yet it can be to set in meticulousr mode.
In addition, in the second above-mentioned embodiment, show that in the example that is demonstrated motion picture parameter PM changes all the time, yet, if motion picture parameter MP
1And MP
2Variation be rapid, might show that so motion picture parameter PM does not change.
In addition, in second embodiment, do not mention the period of change that shows motion picture parameter PM, yet, show that motion picture parameter PM may be the mid point change at a line period.
In addition, in second embodiment, in the example that is demonstrated processed be two systems comprise digital of digital video data D
PWith digital of digital video data D
EPMoving picture data and the still image data D of a system
SPYet if moving picture data is made up of a system, blanking is than itself being continually varying so.Configuration and function can be utilized as much as possible mutually in above-mentioned embodiment.
In addition, in each embodiment, processed in the example that is demonstrated is digital of digital video data, yet this invention goes for the situation of treatment of simulated vision signal.
In addition, in each embodiment, motion vector is detected in the example that is demonstrated, and the motion picture parameter is set according to motion vector, yet the motion of image is based on the dependency relation of successive frame, and is based upon that basis and goes up motion picture parameter and can be set.
In addition, in each embodiment, liquid crystal indicator changes the blanking ratio automatically in the example that is demonstrated, yet the observer can change the blanking ratio according to his hobby and the kind of digital of digital video data (for example, I sports program).
In addition, in each embodiment, blanking is compared according to the motion picture parameter change in the example that is demonstrated, yet, the blanking signal level that blanking is more fixing than changing.
In addition, blanking ratio and blanking signal level can be according to the motion picture parameter changes.
The present invention goes for the monitor of the information processor such as television receiver, personal computer.