Background technology
Lcd technology is progressively substituting traditional cathode ray tube (CRT) display technique with its many advantage on display effect.Liquid crystal display is carried out light output switching by picture element matrix and is come display image, pixel itself does not possess the ability of active illuminating, need provide efficiently by back light system, light source transmission uniformly realizes light output, this is different from the mode of the sort of scanning imagery of CRT, thereby liquid crystal display can not produce flickering.
But, LCD, especially Thin Film Transistor-LCD (Thin FilmTransistor-Liquid Crystal Display, hereinafter to be referred as TFT-LCD) type of drive make screen keep the show state of a frame complete picture in a long time, content when having loaded the next frame picture on the screen just changes, and promptly liquid crystal indicator has maintenance (Hold Type) characteristic in videograph process.This display characteristic can make the people visually produce the phenomenon of smear when on the picture during object rapid movement.This is because people's vision system has very complicated apperceive characteristic, and visual persistence is exactly one of very important characteristic wherein.That is to say that the subjective luminance of vision system institute perception always lags behind the light signal that affacts human eye.When external optical signal acted on human eye, vision system can not produce corresponding brightness sensation immediately, but need one of experience ascending gradually, finally reach stable brightness sensation process.Equally, after the light signal that affacts human eye disappears, the original subjective luminance sensation of vision system can not disappear immediately yet, but a decay is gradually arranged, until the deferring procedure of last disappearance, this phenomenon just is called eye storage characteristic, human visual system's average visual persists the time greatly about about 0.1 second, and can be slightly variant because of the color various durations of thorn laser rays.Do the time spent when human eye is subjected to the periodically variable light pulse signal of brightness, if the frequency that signal changes is enough high, the effect quiescent interval is less than the retentivity time of eye of human eye, and human eye will think that what see is signal continuous, flicker free.But the moving object speed on picture is very fast, and when difference was big between the two frame pictures, then in vision system, previous frame picture that fades away and the next frame picture of setting up gradually can overlap, thereby produce smear.
For solving smear problem, attempt in the prior art replacing conventional fixed to continue luminous mode with scanning backlight, realization is lined by line scan, so just imitated cathode-ray tube (CRT) (Crystal RayTube largely, hereinafter to be referred as CRT) in the electron gun scanning theory, make that the signal switching mode and the pulsed among the CRT of pixel are approximate, avoid the smear of dynamic menu with this.
A kind of specific embodiments in the existing scanning backlight source technology, can referring to application number the United States Patent (USP) of US2004/0047141, in this patent the linear backlight that is arranged on the light guide plate both sides originally is arranged between light guide plate and the display panels, directly provide light source from the display panels dead astern, and be that cold-cathode fluorescence lamp (the to call CCFL in the following text) fluorescent tube that be arranged in parallel is provided with rotatable backlight reflecting plate, on the backlight reflecting plate of sealing, be provided with an opening, when the opening of rotary reflection plate mechanically during towards display panels, then the CCFL light in this reflecting plate can be injected in the display panels, the opening CCFL in the reflecting plate of display panels dorsad then can't be injected light to display panels, and the rotary reflection plate can be realized scanning backlight one by one.The light source that this technical scheme adopted is CCFL, is a kind of LCD light source commonly used, still, this linear light sorurce size of CCFL is bigger, is subjected to the restriction of its size, and the quantity of scanning fluorescent tube can not be too many, so can not be suitable with each the row pixel cell corresponding, can not effectively solve smear problem.And this technical scheme adopts physical construction to rotate scanning backlight, and meeting backlight changes with reflecting plate anglec of rotation difference, and brightness instability, display effect are not good, and physical construction is also complicated simultaneously, realizes the cost height.On the other hand, backlight used in the prior art is as CCFL, can only send white light source,, make it need be lasting luminous with constant brightness again because itself and the corresponded manner of pixel cell, the contrast of so not only brightness, color is low, and the energy consumption of backlight is also higher.
Summary of the invention
Fundamental purpose of the present invention is to provide a kind of method for driving backlight source of liquid crystal display apparatus by some embodiment, can obviously reduce the picture smear phenomenon of LCD, improve brightness, color contrast simultaneously, effectively improve display effect, and reduce the backlight energy consumption.
A further object of the present invention is to provide a kind of backlight source of liquid crystal display apparatus by some embodiment again, can obviously reduce the picture smear phenomenon of LCD, improves brightness, color contrast simultaneously, effectively improves display effect, and reduces the backlight energy consumption.
For realizing fundamental purpose of the present invention, the technical scheme by some embodiment provide a kind of method for driving backlight source of liquid crystal display apparatus comprises the steps:
Step 1, calculate the indicating characteristic value of each pixel region according to vision signal, and according to vision signal and each pixel region indicating characteristic value generation backlight control signal, wherein, the step of calculating each pixel region indicating characteristic value according to vision signal is specially: the color threshold values and the brightness value that calculate each pixel region according to vision signal;
Step 2, the backlight control signal is sent to the each point backlight, wherein, the corresponding pixel of some backlight;
Step 3, the point backlight is according to the backlight control signal, synchronously open or close with the procedure for displaying of pixel on the display panels with behavior unit, and the indicating characteristic value when opening according to the adjustment of backlight control signal, indicating characteristic value during described the unlatching is for opening the color threshold values and the brightness value of time point backlight, wherein, the first row point backlight begins back delay setting-up time at described video signal frame and opens, wherein, the step that the some backlight is opened or closed with behavior unit is specially: after delegation's point backlight is opened, close after continuing for some time, then carry out the unlatching of next line point backlight.
Can know by above technology, the technique scheme of method for driving backlight source of liquid crystal display apparatus of the present invention has realized control respectively that a some backlight is opened or closed, but the shown image in respective pixel unit is controlled the indicating characteristic value of each point backlight respectively simultaneously, and the indicating characteristic value comprises color threshold values and/or brightness value at least.
Be to realize a further object of the present invention, the technical scheme by some embodiment again provide a kind of backlight source of liquid crystal display apparatus comprises: the backlight dot matrix, form by the some backlight of corresponding setting with pixel cell; Control device, being used for the reference mark backlight opens or closes, wherein: the some backlight is the colour point backlight of controllable color, a described some backlight is corresponding with a described pixel cell, and control device is connected respectively with the each point backlight, the procedure for displaying that is used to control pixel on each point backlight and the display panels is synchronously opened or is closed, and color and/or the brightness of control when opening, wherein, the reference mark backlight is opened or is closed and is specially: after control delegation's point backlight is opened, close after continuing for some time, then carry out the unlatching of next line point backlight.
By above technical scheme as can be known, in this backlight source of liquid crystal display apparatus, the ranks matrix that adopts colored pointolite composition is as backlight, avoided the size restrictions of linear light source, the point backlight of fair amount can be set with respect to Pixel Dimensions, and be connected respectively with the each point backlight by control device, color, brightness that can the reference mark light source also can be controlled its unlatching flexibly or closes.
Therefore, backlight source of liquid crystal display apparatus of the present invention and backlight drive method have following advantage:
1, the some backlight is corresponding mutually with pixel cell, and the drive point backlight is opened or closed line by line, can effectively avoid the smear phenomenon, improves display effect;
2, the color and the brightness of some backlight can be adjusted according to the shown image of pixel cell, can improve color, luminance contrast that image shows, have improved display effect;
3, the some backlight is not to continue luminously, and its brightness is to be provided with on demand, so can reduce the energy consumption of backlight.
Also in conjunction with the accompanying drawings the present invention is described in further detail below by specific embodiment.
Embodiment
Method for driving backlight source of liquid crystal display apparatus embodiment
Be illustrated in figure 1 as the process flow diagram of method for driving backlight source of liquid crystal display apparatus specific embodiment of the present invention, the driving process of present embodiment backlight is carried out synchronously with the process that drives the pixel display image, after the vision signal input control device, produce horizontal data signal and vertical scanning signal, the demonstration of pixel on the control display panels, simultaneously, the driving flow process of present embodiment backlight also begins to carry out, and comprises the steps:
Steps A 1, control device are calculated the indicating characteristic value of each pixel region according to vision signal, and this indicating characteristic value comprises color threshold values and/or brightness value at least, and produces the backlight driver control signal according to vision signal and each pixel region indicating characteristic value;
Steps A 2, control device send to the each point backlight with the backlight control signal;
Steps A 3, some backlight are opened or are closed with behavior unit according to the backlight control signal, and the indicating characteristic value when opening according to the adjustment of backlight control signal, promptly are at least color threshold values and/or brightness value when adjusting self unlatching.
Among the above-mentioned steps A1, control device can only be controlled brightness or color, also can control simultaneously.Control color by control color threshold values, and control its brightness by the power of control backlight.
Among the above-mentioned steps A3, one of concrete mode that the some backlight is opened or closed with behavior unit can for:
A first row point backlight is promptly lighted in steps A 301, unlatching, after continuing to light a period of time, closes, and promptly extinguishes first a row point backlight;
Steps A 302, light next line point backlight, after continuing to light a period of time, extinguish this row point backlight, circulation execution in step A302, to the last delegation's point backlight extinguishes.
Said process can be opened or close with a behavior unit, as shown in Figure 2, and also can be with two row, even triplex row etc. is a unit.
The another kind of concrete mode of above-mentioned steps A3 can for:
Steps A 311, light preceding two row point backlights, continue to light a period of time;
Steps A 312, light the third line point backlight when extinguishing the first row point backlight, continue to light a period of time;
Steps A 313, the some backlight that extinguishes previous row are lighted next line point backlight simultaneously, continue to light a period of time, circulation execution in step A313, and to the last delegation's point backlight extinguishes.
There is the overlapping region in the point backlight that technique scheme is promptly lighted successively, and the overlapping region can be a delegation, as shown in Figure 3, also can be multirow.
The mode of opening or closing with the some backlight of behavior unit can also have multiple, can light successively from top to bottom, also can be according to other rule scanning, for example, the point backlight of opening is capable to have certain angle with the liquid crystal panel edge, promptly from the oblique scanning in a certain angle.
In the above-described embodiments, putting the unlatching of backlight or closing all is the pulsed drive that are subjected to the backlight control signal, this pulse signal can be controlled by the variation of liquid crystal panel vertical scanning signal, a kind of pulse signal concrete form that is wherein adopted as shown in Figure 4, the first horizontal pulse signal is vision signal (STV) among Fig. 4, the first horizontal pulse signal is the commencing signal of row, it also is the commencing signal of liquid crystal panel display image one frame, the second horizontal pulse signal is the clock pulse signal (CPV) of liquid crystal panel row, the third line is backlight start signal (CPV '), L1 is the frame period, L2 is that first row point backlight is opened the time delay that begins with respect to liquid crystal panel one frame, L3 is the clock pulse signal cycle of liquid crystal panel row, L4 is that first row point backlight is lighted the retention time, corresponding one by one each the row point backlight of each row of following n1~nn, some backlight are lighted when pulse reaches high level and are continued luminously, then extinguish when pulse reaches low level.
The technical scheme of the foregoing description, this backlight control signal drive point backlight is lighted line by line from top to bottom and is extinguished, synchronous with the procedure for displaying of pixel on the display panels, can effectively avoid the generation of smear phenomenon, improve the visual effect that the people brings that is shown to of liquid crystal indicator, and also saved the power supply energy consumption than lasting luminous backlight.
In the technical scheme of present embodiment, some backlight can corresponding pixel, and the color threshold values of this backlight and/or brightness value are promptly decided according to the color and/or the brightness of the shown image of this pixel so.Point backlight also can corresponding a plurality of pixels, i.e. pixel region, and control device need calculate the color average and/or the average brightness of the shown image of this area pixel so, as the color threshold values and/or the brightness value of a backlight.Color threshold values and/or brightness value control respective point backlight to calculate can make shown color of a backlight and/or brightness consistent in the color and/or the brightness of respective pixel or subregion with the display panels epigraph.
Adopt technique scheme, the color and/or the brightness of some backlight can be controlled according to its pairing pixel shown color of image and/or brightness, be consistent with color of image and/or brightness, then can significantly improve the contrast of the shown image of liquid crystal indicator, color is more bright-coloured, and display effect is better.
The point backlight that is adopted in the foregoing description can but be not limited to colorful light-emitting diode (LightEmitting Diode, hereinafter to be referred as LED), also can be other forms, in addition, development along with the LED technology, can also further reduce the volume of LED, thereby reduce the thickness of backlight source of liquid crystal display apparatus, reduce the size of liquid crystal indicator.
Backlight source of liquid crystal display apparatus embodiment
Be illustrated in figure 5 as the structural representation of backlight source of liquid crystal display apparatus specific embodiment of the present invention, this backlight source of liquid crystal display apparatus comprises: be arranged on display panels 1 back, with the corresponding some backlight 3 of pixel cell 2 on the display panels 1, be the LED 3 of color tunable, be used for driving LED 3 control of turning devices, this control device is connected respectively with each LED 3, is used to control the unlatching of LED3 or closes and color and/or the brightness of LED3 when opening.
In concrete the application, the control device of backlight generally is wholely set with the controller that drives the pixel cell display image, not only controls the unlatching of backlight or closes, and also controls pixel cell 2 display images.The control device of backlight can be made up of control module and backlight source driving circuit.Can adopt field programmable gate array (Field Programable Gate Array, hereinafter to be referred as FPGA) 4 as control module, control module is used for receiving video signals, and generation horizontal data signal and vertical scanning signal, be transferred to coupled source electrode drive circuit 5 and gate driver circuit 6 respectively, so that the pixel cell on the display panels 12 is controlled display image.FPGA 4 also produces the backlight control signal simultaneously and sends to coupled backlight source driving circuit 7, this backlight source driving circuit 7 links to each other with each LED 3, color and/or brightness when controlling its unlatching respectively, and with the unlatching of behavior unit control LED 3 or close, be the unit that delegation or two goes or more the LED 3 of multirow is an execution action, open together or close together.
The concrete course of work of present embodiment can adopt the embodiment of method for driving backlight source of liquid crystal display apparatus of the present invention, the LED3 that control device drives with behavior unit opens or closes, thereby realize the backlight scanning technique, reduce the smear phenomenon, and further according to color and/or the brightness of the LED3 of the color of pixel cell 2 shown images and/or brilliance control correspondence, improve the color of image and/or brightness, contrast, improve display effect.
Further, in the present embodiment, LED3 can corresponding pixel cell 2, also can be corresponding two or three or more a plurality of pixel cell 2, the quantity of LED3 institute respective pixel unit 2 should be able to guarantee display effect, sets as the case may be.This technical scheme not only can solve the problem of smear phenomenon, and the quantity of minimizing LED that can also be suitable is saved cost.
One of ordinary skill in the art will appreciate that: all or part of step that realizes said method embodiment can be finished by the relevant hardware of programmed instruction, aforesaid program can be stored in the computer read/write memory medium, this program is carried out the step that comprises said method embodiment when carrying out; And aforesaid storage medium comprises: various media that can be program code stored such as ROM, RAM, magnetic disc or CD.
It should be noted that at last: above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the spirit and scope of various embodiments of the present invention technical scheme.