CN101685610A - Driving method of liquid crystal display device - Google Patents

Abstract

The invention discloses a driving method of a liquid crystal display device, which is applicable to normally-black liquid crystal display devices. The liquid crystal display device comprises a first display screen with a plurality of first pixels, a backlight source, and an adjusting screen with a plurality of second pixels. The method comprises the following steps: when the first pixels on the display screen display black pictures, changing the voltage of the corresponding second pixels on the adjusting screen to greatly reduce the intensity of the light entering the first pixels; and when the display patterns of the first pixels in the display screen are non-black pictures, applying a voltage to the corresponding second pixels on the adjustment screen by using a time sequence generator during an initial time interval when the video data of the display screen is applied, and continuously applying the voltage during the time period for holding the video data till the first pixels display black pictures. The driving method for the liquid crystal display device enables the liquid crystal display device to realize dynamic contrast adjustment technology by using sub-pixels as a region.

Description

The driving method of liquid crystal indicator

The application is dividing an application of following application:

Denomination of invention: liquid crystal indicator and drive unit thereof, driving method

The applying date: on May 9th, 2008

Application number: 200810037184.3

Technical field

The present invention relates to a kind of driving method of liquid crystal indicator, particularly relate to a kind of driving method that can improve the liquid crystal indicator of dynamic contrast.

Background technology

LCD is one of present most widely used flat-panel monitor.LCD can be carried out the sign of display performance with a plurality of optical parametrics, as brightness, contrast, response speed, visual angle etc.Wherein, contrast is an important optical parametric, and the raising of contrast can make the contrast effect of picture strengthen, and shows good stereovision, also is conspicuous to the lifting of display effect.

The method that improves contrast has two kinds: a kind of is the brightness that improves white attitude picture, and this method realizes easily, but too high brightness meeting causes light leak serious, image fault, the user also can feel more dazzling in the process of using, bring power consumption to increase problems such as life of product shortening simultaneously.Another kind method is to reduce the brightness of the black attitude picture of LCD.

Liquid crystal indicator can be divided into three parts, module backlight, liquid crystal cell and driving circuit section.Liquid crystal itself is non-luminous, mainly is that the light that under the effect of electricity backlight is sent is modulated, and plays the effect of " light valve ", control light pass through what.Black attitude picture is exactly the complete closing state of liquid crystal light valve, yet, in this state,, still have micro-transmittance to come out because backlight is in opening always, the brightness of black attitude is approximately 0.1～1.0cd/m2.The state that backlight is opened always limits the reduction amplitude of black attitude brightness to some extent, and contrast can not be increased dramatically.

Can allow the brightness of black attitude reduce greatly by the brightness of closing or reduce backlight, thereby contrast can be largely increased.Dynamically adjust the brightness of backlight by the monochrome information in the real-time analysis input signal, can reach the better contrast effect, the contrast of this moment can characterize with " dynamic contrast " parameter.The promptly dynamic backlight intensity of adjusting is dynamically promoted contrast.

In the dynamic contrast technology, the backlight of use is generally the light emitting diode (LED) of the cold-cathode fluorescent of straight-down negative (CCFL) fluorescent tube or array.The fluorescent tube of CCFL is longer, the brilliance control of the corresponding a plurality of display pixel area of fluorescent tube, and LED is subjected to encapsulation technology at present, and the restriction of heat dissipation technology and cost can not realize the back light source structure of the corresponding sub-pixel of a LED.Therefore, present dynamic adjustment technology backlight can only be controlled the brightness in backlight piece zone, is easy to generate the cross-luma problem, and to sharpness, color restoration capability etc. are influence to some extent also.And if can in the zone of sub-pixel size, realize the dynamic contrast adjustment then can realizing better display effect.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of driving method of liquid crystal indicator, and making this liquid crystal indicator can be that the dynamic contrast adjustment technology is realized in the zone with the sub-pixel.

For addressing the above problem, the invention provides a kind of driving method of liquid crystal indicator, be applicable to the liquid crystal indicator of normal black pattern, described liquid crystal indicator comprises a display screen, is formed with a plurality of first pixels; One backlight; One adjusts screen, is formed with a plurality of second pixels; This method may further comprise the steps: when first pixel on the display screen is shown as picture black, go up corresponding second pixel change voltage to adjusting screen, the light intensity that enters first pixel is significantly reduced; When the display pattern of first pixel in detecting display screen is non-black picture, in to the initial time interval that applies the display screen video data, timing sequencer applies voltage to adjusting corresponding second pixel of screen, and be continuously applied voltage in the retention time at video data, show black picture until first pixel.

The driving method of liquid crystal indicator of the present invention, adjust screen owing between display screen and backlight, be provided with one, adjusting screen can be according to the input signal of display screen, in the scope of pixel region, real-time adjustment enters the size of the incident light of display screen, and the dynamic contrast of display screen is improved.

Description of drawings

For above-mentioned purpose of the present invention, feature and advantage can be become apparent, below in conjunction with accompanying drawing the specific embodiment of the present invention is elaborated, wherein:

Fig. 1 is the structural representation of traditional liquid crystal indicator;

Fig. 2 is the structural representation of liquid crystal indicator of the present invention;

Fig. 3 is the adjustment screen structural representation in the embodiment of the invention;

Fig. 4 is the structural representation of the embodiment of the invention;

Fig. 5 is the structural representation of the embodiment of the invention;

Fig. 6 is the structural representation of the embodiment of the invention;

Fig. 7 is the block diagram of drive unit embodiment of the present invention.

Among the figure:

1. display screen

10. second substrate, 101. first pixels

11. first substrate

12. first liquid crystal layer

13. first oriented layer

14. first Polarizer

15. second Polarizer

2. backlight

3. adjust screen

30.tetrabasal 301. second pixels

31. the 3rd substrate

32. second liquid crystal layer

33. second oriented layer

34. the 3rd Polarizer

35. the 4th Polarizer

4. Polarizer

5. time schedule controller

6. first data driver

7. first grid driver

8. first gamma voltage generator

9. second data driver

10. second grid driver

11. second gamma voltage generator

Embodiment

The invention will be further described below in conjunction with accompanying drawing and exemplary embodiments.

Fig. 2 is the structural representation of liquid crystal indicator of the present invention; Fig. 3 is the adjustment screen structural representation in the embodiment of the invention.

Please refer to Fig. 2, liquid crystal indicator of the present invention comprises adisplay screen 1, abacklight 2 and anadjustment screen 3, adjustsscreen 3 betweendisplay screen 1 and backlight 2.The structure ofdisplay screen 1 is identical with the display screen structure of existing liquid crystal indicator, as shown in Figure 1, comprisefirst substrate 11 andsecond substrate 10 that are oppositely arranged, be filled in first pixel 101 that is formed with a plurality of one-tenth arranged on first liquid crystal layer, 12, thesecond substrates 10 betweenfirst substrate 11 andsecond substrate 10;Backlight 2 is positioned atdisplay screen 1 back, fordisplay screen 1 provides light source; Adjustscreen 3, be used for dynamically adjusting the incident intensity ofdisplay screen 1, with reference to Fig. 3, adjustscreen 3 and comprise the3rd substrate 31 and the tetrabasal 30 that is oppositely arranged, be filled in secondliquid crystal layer 32 between the3rd substrate 31 and thetetrabasal 30, be formed withsecond pixel 301 of a plurality of one-tenth arranged on thetetrabasal 30, the position of describedadjustment screen 3 anddisplay screen 1 are aimed at, andsecond pixel 301 of adjustingscreen 3 is corresponding one by one with first pixel 101 ofdisplay screen 1.

Describedfirst substrate 11 is a color membrane substrates, and inside surface exists black matrix layer, look resistance layer, flatness layer, common electrode layer and first orientedlayer 13 successively; Describedsecond substrate 10 is an array base palte, first pixel 101 is by thin film transistor (TFT) (TFT) switch drive, it is under the situation that does not apply electric field that there is the effect of pixel electrode and first oriented layer, 13, the first orientedlayer 13 in inside surface, and liquid crystal molecule is arranged along specific direction.

In order to manufacture conveniently, adjusting structure, the material ofscreen 3 anddisplay screen 1 and form can be identical, also can do a little change.As in order to increase brightness, adjust the look resistance layer ofscreen 3 and can remove, keep black matrix layer, the3rd substrate 31 is changed to black matrix base plate, the purpose that black matrix keeps is to cover the TFT device of adjustingscreen 3, prevents that outer illumination is mapped on the TFT, produces leakage current.

Fig. 4 is the structural representation of the embodiment of the invention.Please refer to Fig. 4, the outside surface of describedfirst substrate 10 is provided withfirst Polarizer 14, the outside surface of describedsecond substrate 11 is provided withsecond Polarizer 15, the outside surface of described the3rd substrate 31 is provided with the3rd Polarizer 34, the outside surface of describedtetrabasal 30 is provided with the4th Polarizer 35, describedfirst Polarizer 14 is parallel with the absorption axes direction of the3rd Polarizer 34, describedsecond Polarizer 15 is parallel with the absorption axes of the4th Polarizer 35, andfirst Polarizer 14,second Polarizer 15 are vertical with the absorption axes direction of the3rd Polarizer 34, the 4th Polarizer 35.In this structure,display screen 1 andadjustment screen 3 are wanted accurate contraposition and fixing.Used 4 Polarizers in this structure altogether, the transmitance of whole device is lower, can reduce Polarizer quantity.

Please refer to Fig. 5, compare Fig. 4, this liquid crystal indicator has used 3 Polarizers altogether, i.e.first Polarizer 14,second Polarizer 15 and the4th Polarizer 35, describedfirst Polarizer 14 is parallel with the absorption axes direction of the4th Polarizer 35, and vertical with the absorption axes direction of second Polarizer 15.This structure can improve the whole transmitance of liquid crystal indicator.

Please refer to Fig. 6, the liquid crystal indicator of the embodiment of the invention can only adopt 2 Polarizers.The outside surface that is describedfirst substrate 11 is provided withfirst Polarizer 14, the outside surface ofsecond substrate 10 is provided withsecond Polarizer 15, the absorption axes of describedfirst Polarizer 14 andsecond Polarizer 15 is vertical mutually, and what it adjustedscreen 3 employings is spiral phase liquid crystal (PSCT) display device structure of polymer stabilizing.PSCT has such characteristic, by changing the voltage that applies on it, can make and adjustscreen 3 conversion mutually between scattering states and transmission state.

The embodiment of the invention has also proposed corresponding driving method, first pixel 101 ofdisplay screen 1 is x,second pixel 301 of adjustingscreen 3 is x ', the pixel x ' that adjustsscreen 3 is corresponding with the pixel x ofdisplay screen 1, whendisplay screen 1 certain pixel x is shown as picture black, can change voltage (apply voltage or remove voltage) to the x ' pixel of adjusting corresponding display screen x pixel on thescreen 3, the light intensity by adjusting screen x ' pixel is significantly reduced, significantly reduce even enter the light intensity of display screen x pixel.When liquid crystal display was normal white display mode, liquid-crystal apparatus did not apply voltage in original state to the liquid crystal of adjusting screen.The display pattern of certain sub-pixel x is when deceiving picture in detecting display screen, in to the initial time interval that applies the display screen video data, 5 pairs of timing sequencers are adjusted the corresponding x ' pixel of screen and are applied voltage, and be continuously applied voltage in the retention time at video data, no longer show black picture until the x pixel.

If liquid crystal display is normal black display mode, liquid-crystal apparatus does not apply voltage in original state to the liquid crystal of adjusting screen 3.When the display pattern of certain sub-pixel x is non-black picture in detectingdisplay screen 1, in to the initial time interval that applies the display screen video data, 5 pairs of timing sequencers are adjustedscreen 3 corresponding x ' pixels and are applied voltage, and be continuously applied voltage in the retention time at video data, show that until the x pixel black picture removes the driving voltage of adjusting screen again.

In the concrete application of above embodiment, when display screen pixel x is shown as picture black, can go up x ' the pixel change voltage (apply voltage or remove voltage) of corresponding display screen x pixel to adjusting screen, light intensity by adjusting screen X ' is significantly reduced, significantly reduce even enter the light intensity of display screen x pixel, thereby reach the effect of dynamic raising contrast.

Fig. 7 is the block diagram of patent drive unit of the present invention.Time schedule controller 5 is respectively byfirst data driver 6 ofdisplay screen 1, thefirst grid driver 7 ofdisplay screen 1, and aγ voltage generator 8 makesdisplay screen 1 can access demonstration.The oneγ voltage generator 8 can produce m γ voltage, and wherein V1 is a minimum voltage, and Vm is a ceiling voltage.

Time schedule controller 5 passes through to adjust second data driver 9 of screen 3, the second grid driver 10 of adjustment screen 2 respectively, and 11 pairs of adjustment screens 3 of the 2nd γ voltage generator drive.11 of the 2nd γ voltage generators produce 2 γ voltages, are respectively the V1 minimum voltage, the Vm ceiling voltage.In time schedule controller 5, there is a logical circuit, is used for judging and applies voltage V1 or Vm for adjustment screen 3.With normal white display mode is example, when voltage be minimum voltage V1 is normal white attitude with adjusting screen 3 not applying voltage (V1=0V) or apply at display screen 1, and the logical circuit in the time schedule controller 5 has first logical value 0.Display screen 3 is by a γ voltage generator 8 normal display frames, when picture is deceived in the demonstration of display screen x pixel, the voltage that 8 couples of display screen x of the one γ voltage generator pixel applies is Vm, at this moment, logical circuit changes to second logical value 1 in the time schedule controller 5, and judges in view of the above in the initial time of x pixel video data, and the x ' pixel corresponding with the x pixel applies voltage Vm on the screen 3 to adjusting, the light intensity that enters the x pixel is significantly reduced, thereby improve contrast dynamically.X ' pixel is continuously applied voltage Vm in black picture video data hold time, no longer shows black picture until the x pixel.Logical circuit judges that the x pixel for black picture, then is returned to first logical value 0, and the x ' pixel of adjusting screen is applied voltage V1.

If the brightness of backlight is 5800cd/m2, the transmitance of Polarizer monomer is 43%, use traditional display device, the penetrance of display screen is 5.6%, the brightness that is bright attitude is 324cd/m2, and the penetrance of dark attitude is 0.005%, and the brightness of dark attitude is about 0.3cd/m2, and contrast can reach 1080: 1.And use display device embodiment of the present invention, and when display screen matrix x shows the black picture, can shield the X ' pixel that goes up corresponding display screen x pixel to adjustment simultaneously to apply voltage, the light intensity that enters the x pixel that makes of dynamic real-time reduces.If this moment, back light source brightness brought up to 12,000cd/m2, the transmitance of whole device is 1.25%, the brightness of bright attitude is 150cd/m2, and the penetrance theoretical value of dark attitude is 0.000025%, the dark attitude brightness of x pixel can be far smaller than 0.015cd/m2, and its dynamic contrast can be considerably beyond 10,000: 1.

Though the present invention discloses as above with preferred embodiment; right its is not in order to qualification the present invention, any those skilled in the art, without departing from the spirit and scope of the present invention; when can doing a little modification and perfect, so protection scope of the present invention is when with being as the criterion that claims were defined.

Claims (1)

1, a kind of driving method of liquid crystal indicator is applicable to normal liquid crystal indicator of deceiving pattern, and described liquid crystal indicator comprises a display screen, is formed with a plurality of first pixels; One backlight; One adjusts screen, is formed with a plurality of second pixels; This method may further comprise the steps:

When first pixel on the display screen is shown as picture black, go up corresponding second pixel change voltage to adjusting screen, the light intensity that enters first pixel is significantly reduced;

When the display pattern of first pixel in detecting display screen is non-black picture, in to the initial time interval that applies the display screen video data, timing sequencer applies voltage to adjusting corresponding second pixel of screen, and be continuously applied voltage in the retention time at video data, show black picture until first pixel.

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