CN202178047U - Liquid crystal display backlight device with integral light-adjusting function - Google Patents
Liquid crystal display backlight device with integral light-adjusting function Download PDFInfo
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- CN202178047U CN202178047U CN2011203127862U CN201120312786U CN202178047U CN 202178047 U CN202178047 U CN 202178047U CN 2011203127862 U CN2011203127862 U CN 2011203127862U CN 201120312786 U CN201120312786 U CN 201120312786U CN 202178047 U CN202178047 U CN 202178047U
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Abstract
The utility model relates to a liquid crystal display backlight device with an integral light-adjusting function, which comprises a light-emitting diode (LED) light-adjusting plate, a video signal interface plate, an LED driving plate, a field programmable gata array (FPGA) (programmable logic) control plate, a power supply plate and a liquid crystal screen interface plate. A video signal is decoded by a video signal interface plate and then enters the FPGA control plate, and an LED brightness adjusting signal output by the FPGA control plate and liquid crystal image element brightness adjusting signals are respectively connected to the LED driving plate and the liquid crystal screen interface plate. An LED backlight source needs no split arrangement and control and is small in control channel, low in hardware cost and free of local light interference influencing display quality.
Description
Technical field
The utility model relates to technical field of liquid crystal display, particularly a kind of LCD backlight device with integrally adjusting light function.
Background technology
(Liquid Crystal Display LCD) through the development in 30 years, has become the mainstream technology of FPD in liquid crystal display.Liquid crystal molecule itself is not luminous, needs the backlighted viewing area.The LCD backlight that uses at present mainly contain cold-cathode fluorescence lamp (Cold Cathode Fluorescent, CCFL) and light emitting diode (Light Emitting Diode, LED) two kinds.LED has advantages such as life-span length, environmental protection, response time is fast, just progressively enlarges in the application of field of liquid crystal display.
There are two inherent defects in liquid crystal display: (1) contrast is low; (2) power consumption is big.Many researchers adopts dynamic light adjustment technology backlight to improve the liquid crystal display contrast at present, cuts down the consumption of energy simultaneously.Can the dynamic light adjustment technology be divided into overall light modulation and local dimming according to backlight brightness regulation method.Overall situation light modulation is the whole backlight illumination that changes, and local dimming then is to be divided into the zone that several can be controlled separately with backlight, confirms the backlight illumination that this is regional according to the eigenwert of this zone correspondence image.With respect to local dimming, overall light modulation need not carried out zoning design, control to backlight, and required control chip is few, and hardware cost is low.Owing to do not need subregion, do not have the light cross-interference issue that exists in the present local dimming method.The overall situation light modulation also have an outstanding benefit be can either direct-type backlight also can side go out formula backlight in the realization, can satisfy the requirement that volume is frivolous, contrast is high, energy consumption is low simultaneously.
The patent of invention " method and the device thereof of LED-backlit source integrally adjusting light " that University of Fuzhou proposes (application number: 200910309165.6) need preset backlight light-adjusting degree of distortion; According to this degree of distortion image is compressed, combine extraneous brightness to confirm the backlight dimming parameter simultaneously.This utility model is not carried out any adjusting to the liquid crystal pixel gray scale, can suitably improve dynamic contrast, but can't improve static contrast.
Patent of invention " side light type LED back light dynamic partition the control method " (application number: 201010510536.X) proposed a kind of side that can be used in and gone out formula local dimming method backlight that Guangzhou Skyworth Flat Panel display Science and Technology Co., Ltd proposes.LED is arranged on four sides of LGP, and the zone that horizontal longitudinal direction LED intersects is the control area of these LED, realizes local dimming with this.This utility model goes out formula in side and realized local dimming on backlight, and is different with the overall light modulation of the utility model, also is not suitable for direct-light type LED backlight.
The patent of invention that Qingdao Hisense Electric Appliance Co., Ltd obtains the authorization " method of adjustment of liquid crystal display contrast and device " (application number: 200710111510.6) proposed a kind of method that can improve the liquid crystal display dynamic contrast; After the backlight dimming factor is confirmed; Take identical adjustment coefficient to adjust to all liquid crystal pixels; This method can improve the liquid crystal display dynamic contrast, can't improve static contrast.
The LED-backlit overall situation light-dimming method that the utility model proposes promptly can be used for direct-type backlight and can be used for side again to go out formula backlight, applied widely.Can only improve the effect of liquid crystal display dynamic contrast to present most of light modulation algorithms, the utility model can improve dynamic contrast, also can effectively improve static contrast.
Summary of the invention
The purpose of the utility model is to provide a kind of overall light-dimming method that is used for the LED-backlit of liquid crystal display; This method had both solved the problem that existing light modulation algorithm can't improve static contrast; Have again simultaneously that control channel is few, hardware cost is low, do not have light advantage such as crosstalk, be applicable to that direct-type backlight and side go out the formula LED-backlit.
Another purpose of the utility model is to provide a kind of back lighting device that helps to improve static contrast of liquid crystal display and dynamic contrast, to solve the problem that the liquid crystal display contrast is not high, energy consumption is big.
For realizing above-mentioned purpose, the utility model adopts following technical scheme:
Said LCD backlight device with integrally adjusting light function comprises led light source plate 101, LED drive plate 102, video signal interface plate 103, FPGA (FPGA) control panel 104, LCD Interface plate 105, power panel 106;
Led light source plate 101 does not need subregion, can be straight-down negative, can be that side goes out formula yet;
Video signal interface plate 103 is connected with video input signals, and the decoded signal of video signal interface plate 103 outputs is connected to the signal input part of FPGA (FPGA) control panel 104;
The LED brightness adjusting signal of FPGA (FPGA) control panel 104 outputs is connected to the signal input part of LED drive plate 102;
Each pixel intensity adjustment signal of the liquid crystal of FPGA (FPGA) control panel 104 outputs is connected to the signal input part of LCD Interface plate 105;
The external liquid crystal display of the signal output part of LCD Interface plate 105;
The signal output part of LED drive plate 102 is connected with led light source plate 101 input ends.
Description of drawings
Fig. 1 is the device block diagram of the utility model.
Fig. 2 is the utility model overall situation light-dimming method process flow diagram.
Fig. 3 is the utility model input picture statistical graph.A is a histogram, and b is the accumulative total histogram.
Fig. 4 is the original S curve of the utility model.
Fig. 5 is the S curve that the utility model is used to improve contrast.Fig. 5 a is to be to be for the more moderate image of brightness ratio for brighter image, Fig. 5 c for darker image, Fig. 5 b
Fig. 6 is the back lighting device instance 1 of the utility model.
Fig. 7 is the back lighting device instance 2 of the utility model.
Embodiment
The core of the utility model is to provide the method for a kind of effective raising liquid crystal display dynamic contrast and static contrast, and this method need be to the subregion that carries out backlight, incoming video signal is carried out statistical study after, generate the backlight brightness values after the light modulation.Simultaneously according to the S curve to liquid crystal each sub-pixel brightness adjust.
See also the device block diagram of Fig. 1.Back lighting device 1 comprises led light source plate 101, LED drive plate 102, video signal interface plate 103, FPGA (FPGA) control panel 104, LCD Interface plate 105 and power panel 106.Led light source plate 101 can be a straight-down negative, also can be that side goes out formula.Video input signals at first gets into video signal interface plate 103 and decodes, and decoded signal gets into FPGA control panel 104.FPGA control panel 104 comprises chips such as programmable logic controller (PLC) FPGA, storer; FPGA analyzes the output signal from video signal interface plate 103; Produce LED brightness adjusting signal and each pixel intensity adjustment signal of liquid crystal according to overall light modulation algorithm, import LED drive plate 102 and LCD Interface plate 105 respectively.Power panel 106 receives electric main, and the DC voltage that needs is provided for each circuit board.
See also the overall light-dimming method process flow diagram of realizing in the FPGA control panel 104 of Fig. 2.At first the output signal from video signal interface plate 103 is carried out analyzing and processing; Obtain characteristic parameters such as pixel grey scale maximal value, the sub-pixel red (R) of whole two field picture, green (G), blue (B) each color maximum brightness value, average gray, colour brightness mean value, confirm the backlight illumination dim factor
k, be shown below:
In the formula,
k 0 Be the dim factor initial value, can select 0.5,0.75 or other values.
bBe the influence coefficient of image to backlight illumination, its value will be considered initial value
k 0 , guarantee
kIn (0,1) scope.For example, when
k 0 Got 0.5 o'clock,
b=510, when
k 0 Got 0.75 o'clock,
b=1020.
Can adopt several different methods to confirm
L Blu Equation 2 has provided several kinds and has confirmed
L Blu Method.First kind of instance is to take each sub-pixel R, G, the peaked method of B brightness.Second instance is to take the peaked method of each sub-pixel gray scale.The 3rd instance is at first to take out each pixel R, G, B brightness maximal value, then all pixel maximal values is averaged the method for computing.The 4th instance is the gray-scale value that at first calculates each sub-pixel, and all grey scale pixel values are averaged computing:
（2）
The adjustment factor backlight
kAfter confirming, according to
kGenerate the PWM drive signal of LED-backlit.If backlight do not have that the dutycycle of pwm signal is R before the light modulation
1, the pwm signal dutycycle that generates after the light modulation is R
2, then
R
2=R
1×k
Because k always is less than or equal to 1,, reduced energy consumption so backlight illumination gets backlight illumination before also always being less than or equal to light modulation after the light modulation.
After backlight illumination is confirmed,, need adjust liquid crystal pixel brightness for the reduction and the raising contrast of compensate for backlight brightness.Different from the past all pixels are taked the method for identical adjusting range, the present invention adjusts separately each liquid crystal pixel brightness according to the S curve, because each pixel adjusting range is different, has effectively improved and shows static contrast.The S curvilinear equation is following:
The S curvilinear equation comprises
AWith
aTwo parameters, wherein
AWith
aRelation be shown below:
In the formula
L g It is S knee point coordinate.The S knee point
L g Determined the setting range of contrast, as shown in Figure 5, brightness greater than
L g The pixel adjustment factor greater than 1, brightness less than
L g The pixel adjustment factor less than 1.For guaranteeing that the light modulation algorithm is applicable to various images, the S knee point
L g By the input picture decision, can be to comprise the brightness value that all pixel certain proportions (as 50%) are corresponding in the accumulative total histogram, also can get all pixel average gray values of image.
See also Fig. 3 curve.Fig. 3 (a) is the statistics histogram of image, and Fig. 3 (b) is the accumulative total histogram of image.N among Fig. 3 (a)
MaxAnd N
MinIt is respectively the brightness value of the maximum and minimum correspondence of quantity in the histogram.H among Fig. 3 (b)
25, H
50, H
75It is respectively the brightness value that comprises the correspondence of all pixels 25%, 50% and 75% in the accumulative total histogram.
L g Can confirm by the eigenwert that obtains among Fig. 3.The method of confirming has various ways, and following formula has provided 5 kinds of possible obtaining value methods:
L g After confirming, get
a=0.22, can obtain according to equation 4
A, obtain the S curve according to equation 3 thus.Fig. 4 is the original S curve that obtains according to equation 3, and its initial point and terminal point through (0,0) and (255,255) 2 points, can't not replenish liquid crystal pixel brightness, so need carry out translation and stretching to curve, obtain the S curve of Fig. 5.Fig. 5 has provided 3 typical S curves.Fig. 5 a is for darker image, and its flex point brightness is lower, thus less to the lower pixel adjustment of gray scale, to avoid image fault than dark-part.Fig. 5 b is for brighter image, and its flex point brightness is higher, thus less to the higher pixel adjustment of gray scale, to avoid image fault than bright parts.Fig. 5 c is for the more moderate image of brightness ratio, and its flex point brightness is placed in the middle, for gray scale low and higher pixel all adjust, improve contrast.After obtaining the S curve, the brightness value L original according to liquid crystal pixel
In(horizontal ordinate) searched the ordinate output L of corresponding S curve
Out, with L
OutSend into the LCD Interface plate.
See also embodiment shown in Figure 61.This instance 1 is that the side with overall dimming function goes out formula LED-backlit device, comprises that side goes out formula LED lamp 601, LGP 602, LED drive plate 603, video signal interface plate 604, FPGA control panel 605, circuit board support 606, power panel 607 and LCD Interface plate 608.Because adopt side to go out mode, the LED quantity that needs is few, all circuit boards can be arranged in the one side of circuit board support 606.
See also embodiment shown in Figure 72.This instance 2 is the direct-light type LED backlight devices with overall dimming function, comprises straight-down negative LED lamp 701, FPGA control panel 702, video signal interface plate 703, LED drive plate 704, circuit board support 705, power panel 706 and LCD Interface plate 707.Owing to adopt straight mode down; The LED quantity that needs is more, needs on the LED drive plate 704 to arrange more chip for driving, possibly cause LED drive plate 704 sizes bigger; All circuit boards can't be arranged in the identical faces of circuit board support 705, so circuit board is installed in the two sides of circuit board support 705.Circuit board that dotted line is represented among Fig. 7 and signal lead are in the distance L ED of circuit board support 705 lamp 701 one side far away, and distance L ED lamp 701 nearer one sides are installed LED drive plate 704.
Embodiment by above the utility model is visible, and the back lighting device of the utility model can be that side goes out formula, also can be straight-down negative.The led light source plate need not carry out zoning design, control, has practiced thrift hardware cost and development time, has overcome subregion and has controlled unavoidable light cross-interference issue.The FPGA control panel that comprises in the utility model; Can adjust backlight illumination in real time according to input picture; According to the S curve each pixel brightness value is adjusted simultaneously, brightness value is adjusted the factor greater than 1 greater than the pixel of flex point, and brightness value is adjusted the factor less than 1 less than the pixel of flex point; Effectively improve static contrast of liquid crystal display and dynamic contrast thus, cut down the consumption of energy simultaneously.
Though through case description the utility model; Those of ordinary skills know; The utility model has many distortion and variation and does not break away from the spirit of the utility model, hopes that appended claim comprises these distortion and variation and do not break away from the spirit of the utility model.
Claims (1)
1. LCD backlight device with integrally adjusting light function, it is characterized in that: said LCD backlight device with integrally adjusting light function comprises led light source plate (101), LED drive plate (102), video signal interface plate (103), FPGA control panel (104), LCD Interface plate (105), power panel (106);
Led light source plate (101) does not need subregion, can be straight-down negative, can be that side goes out formula yet;
Video signal interface plate (103) is connected with video input signals, and the decoded signal of video signal interface plate (103) output is connected to the signal input part of FPGA control panel (104);
The LED brightness adjusting signal of FPGA control panel (104) output is connected to the signal input part of LED drive plate (102);
Each pixel intensity adjustment signal of the liquid crystal of FPGA control panel (104) output is connected to the signal input part of LCD Interface plate (105);
The external liquid crystal display of signal output part of LCD Interface plate (105);
The signal output part of LED drive plate (102) is connected with led light source plate (101) input end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203127862U CN202178047U (en) | 2011-08-25 | 2011-08-25 | Liquid crystal display backlight device with integral light-adjusting function |
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| CN2011203127862U CN202178047U (en) | 2011-08-25 | 2011-08-25 | Liquid crystal display backlight device with integral light-adjusting function |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103606363A (en) * | 2013-12-04 | 2014-02-26 | 中航华东光电有限公司 | LCD type helmet display driving circuit based on FPGA |
| WO2020124881A1 (en) * | 2018-12-20 | 2020-06-25 | 深圳创维－Rgb电子有限公司 | Mini led television control system and method |
| CN112509525A (en) * | 2020-12-02 | 2021-03-16 | Tcl华星光电技术有限公司 | Control method and control device for liquid crystal display backlight module |
-
2011
- 2011-08-25 CN CN2011203127862U patent/CN202178047U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103606363A (en) * | 2013-12-04 | 2014-02-26 | 中航华东光电有限公司 | LCD type helmet display driving circuit based on FPGA |
| WO2020124881A1 (en) * | 2018-12-20 | 2020-06-25 | 深圳创维－Rgb电子有限公司 | Mini led television control system and method |
| US11303842B2 (en) | 2018-12-20 | 2022-04-12 | Shenzhen Skyworth-Rgb Electronic Co., Ltd | Mini LED television control system and method |
| CN112509525A (en) * | 2020-12-02 | 2021-03-16 | Tcl华星光电技术有限公司 | Control method and control device for liquid crystal display backlight module |
| CN112509525B (en) * | 2020-12-02 | 2022-04-26 | Tcl华星光电技术有限公司 | Control method and control device for liquid crystal display backlight module |
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| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120328 Termination date: 20120825 |