CN102890918A - Dynamic backlight driving method - Google Patents
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- CN102890918A CN102890918A CN2012104238965A CN201210423896A CN102890918A CN 102890918 A CN102890918 A CN 102890918A CN 2012104238965 A CN2012104238965 A CN 2012104238965A CN 201210423896 A CN201210423896 A CN 201210423896A CN 102890918 A CN102890918 A CN 102890918A
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Abstract
The invention relates to a dynamic backlight driving method which comprises the following steps of: dividing backlight into a plurality of areas in the vertical direction, wherein the brightness of a backlight source can be independently controlled by backlight in each area; for an image in each area, counting and analyzing an image gray scale of each area, and re-determining the backlight gray of each area; recalculating the image gray scale of each area according to the re-determined backlight gray of each area, so that gray values of pixels passing through the backlight is invariable; and displaying a final image picture on a liquid crystal display panel. According to the scheme, the dynamic backlight driving method is applicable to a direct type backlight mode and an edge-type backlight mode; the problems that the method is only applicable to a single backlight mode of direct type light-emitting diode (LED) backlight and the cost of an external circuit and a driving loop is relatively high due to huge technical data of image data in the prior art are effectively solved; and meanwhile, by the adoption of a pulse wave type backlight driving display panel, smears in a process of moving the image is greatly improved.
Description
Technical field
The present invention relates to a kind of dynamic backlight driving method, particularly a kind of LED-backlit source driving method.
Background technology
In the existing liquid crystal indicator, light emitting diode (LED) few with power consumption and that can improve image quality is made the light source of the backlight of liquid crystal panel.But backlight and vision signal are irrespectively luminous with constant luminance, by control the light transmission rate of liquid crystal panel according to the brightness of vision signal, show the video of desired brightness.Therefore, even darker video, the electric power of backlight can not reduce yet, but constant consumption, electrical efficiency is bad.As its countermeasure, proposed to make the Dimmable of backlight, control the gray shade scale of liquid crystal panel and the brightness of backlight based on the level (level) of incoming video signal, reduce thus power consumption, improve the technology of image quality.In addition, also knownly be divided into a plurality of zones (area) with backlight in vertical and horizontal direction, as shown in Figure 1, to be divided into a plurality of zones as the backlight vertical and horizontal direction of backlight with LED200, be about to the display panel 100 in correspondence backlight is divided into a plurality of zones, distribute for single area statistics image data, distributing according to data calculates this zone gray scale backlight, and recomputating corresponding image data according to this gray scale backlight, the transmission data is also adjusted backlight.But the method is only applicable to direct-light type LED backlight, and the image data computational data is huge, the external circuit cost is higher, this region-type directly descends backlight drive not only to comprise LED and drives the loop and also comprise the backlight drive loop, the driving circuit cost is higher, the liquid crystal panel of this downward back optical drive is thicker simultaneously, and the whole slimming difficulty of liquid crystal indicator is higher.
Summary of the invention
Goal of the invention: the objective of the invention is in order to overcome the above-mentioned mode single backlight that is only applicable to direct-light type LED backlight, and huge because of the image data technical data, and the external circuit cost that causes is higher and drive the higher problem of loop cost.
Summary of the invention: in order to reach above-mentioned goal of the invention, the invention provides a kind of dynamic backlight driving method, be used for display panels, comprise the steps:
Step 1: on vertical direction, be distinguished into a plurality of zones with backlight, and the backlight of each zone can independently be controlled back light source brightness;
Step 2: to each area image, each regional image gray scale of statistical study redefines the gray scale backlight in each zone;
Step 3: according to the gray scale backlight that each zone redefines, recomputate the GTG of each regional image, the gray-scale value that pixel is presented after backlight is constant;
Step 4: display panels shows final image frame.
Wherein, adopt during backlight being lit in described each zone the pulse wave formula to drive;
Further, the frequency of described backlight lightening is identical with the frequency that the show image of described display panels upgrades.
Further, width and the height-adjustable of the pulse wave of described pulse wave formula driving;
Further, the backlight of described each zone lighted when this regional liquid crystal reaction is extremely stablized;
Further, the described GTG of each regional image that recomputates is more than or equal to former ash.
Beneficial effect: by to each regional image gray scale of input and redefining of back light source brightness, be not only applicable to direct-type backlight, also be applicable to the side entrance back mode.Effectively solved the mode single backlight of the only applicable direct-light type LED backlight that prior art exists, and huge because of the image data technical data, and and the external circuit cost that causes is higher and drive the higher problem of loop cost.Adopt pulse wave formula backlight drive display panel, the smear when also significantly improving image and moving.
Description of drawings
Fig. 1 is prior art direct-light type LED backlight mode synoptic diagram;
Fig. 2 is the present invention's synoptic diagram that is divided 4 zones backlight;
Fig. 3 is the pulse wave synoptic diagram that each regional pulse wave formula of the present invention drives;
Fig. 4 is the backlight and panel liquid crystal driving waveform correlation figure in each zone of the present invention;
Fig. 5 is process flow diagram of the present invention;
Fig. 6 is each regional pixel gray level distribution plan of the present invention's one picture image;
Fig. 7 is the present invention zone 1 pixels statistics histogram;
Fig. 8 is the gray scale synoptic diagram backlight that zone 1 of the present invention redefines;
Fig. 9 is the pixel histogram that zone 1 of the present invention is added up again;
Figure 10 is the brightness rank transformation curve figure after the present invention's one original brightness rank correspondence image is processed;
Figure 11 is the framework map that image of the present invention is processed;
Among the figure 100, display panel, 200, LED.
Embodiment
Below in conjunction with the drawings and specific embodiments, further illustrate the present invention, should understand these embodiment only is used for explanation the present invention and is not used in and limits the scope of the invention, after having read the present invention, those skilled in the art all fall within the application's claims limited range to the modification of the various equivalent form of values of the present invention.
Present embodiment describes (this patent is not limited in the LED-backlit mode) with the light emitting diode (light-emitting diode, LED) of side-light type lamp bar design as the structure of the liquid crystal display of backlight.At first LED-backlit source backlight is distinguished into a plurality of zones on vertical direction, present embodiment is distinguished into four zones with LED-backlit source backlight on vertical direction, be about to be distinguished into four zones with the display panel 100 of corresponding liquid crystal display backlight according to backlight on vertical direction.As shown in Figure 2, divide into zone 1, zone 2, zone 3 and zone 4.The independent control in each zone back light source brightness, and adopt when lighting the pulse wave formula to drive as shown in Figure 3 driving pulse wave, the permanent bright formula of difference prior art is backlight.Pulse bandwidth and capable of regulating highly according to actual needs, the frequency of pulse wave is identical with the display panels sweep frequency simultaneously.Because liquid crystal reaction needed time of liquid crystal display, if take the panel of picture update rate 60Hz as example, each pixel can be written into pixel voltage one time every 16.6ms, so regional is backlight should light when stablizing in this regional liquid crystal reaction.And because the liquid crystal display display panel is to adopt the mode of lining by line scan, so its stable time of panel picture element from top to bottom is neither identical.Fig. 4 is the corresponding waveform that the liquid crystal display display panel divides the backlight and liquid crystal reaction in four zones, dotted line is the variation of panel transmitance among the figure, solid line is each zone luminance variations backlight, changed by the transmitance that can find out the panel zones of different among the figure, liquid crystal display-driving adopts the mode of vertical scanning, the sequential that image data writes picture element from top to bottom, the picture element in zone 1 can be written into first voltage, after picture element is written into voltage, the electric field that puts on liquid crystal can change and make the liquid crystal action, this action generally needs tens of milliseconds, therefore the transmitance waveform among the figure can slowly rise or slowly drop to stable, the most stable state of liquid crystal betides before data write next time, therefore before writing picture element, lower secondary data must light (waveform backlight in zone one in such as Fig. 4) backlight, can guarantee that so just image display is correct, after the picture element in zone one all is written into image data, can begin the picture element in zone two is write image data, the write time of picture element and zone two middle picture elements can differ for 1/4th auspicious time of picture in the middle of the zone one, if take the panel of picture update rate 60Hz as example, write time can differ 4.15 milliseconds, because present embodiment is with four districts that are divided into backlight, therefore the write time in zone one and zone two can differ for 1/4th auspicious time of picture, if be divided into eight zones with backlight, then zone one can differ the auspicious time of eighth picture with the write time in zone two, by that analogy, because the picture element write time in zone two is the auspicious time of picture of the delay 1/4th in zone one, therefore liquid crystal reaction to stable state also can postpone for 1/4th auspicious time of picture, so zone two backlight photo the backlight lightening time in zone one also need postpone for 1/4th auspicious time of picture, the rest may be inferred to zone three and zone four.
The simple driving flow process of present embodiment as shown in Figure 5, the below is described in detail each step in the flow process:
Step S501: with backlight in the vertical direction zoning;
Step S502: each regional image gray scale is done statistical study recalculate gray scale backlight;
Step S503: the gray scale that recomputates image according to the gray scale backlight of the new calculating in each zone;
Step S504: show final image frame;
Further describe for above step, the histogram of the pixel gray level distribution statistics in a picture image as shown in Figure 6 and corresponding regional 1, zone 2, zone 3 and zone 4, transverse axis is the GTG value, the longitudinal axis is the statistics numbers of this GTG.Pixel gray level statistic histogram take regional 1 is as example, and the pixel gray level statistic histogram in zone 1 has as shown in Figure 7 drawn a new gray-scale value backlight as shown in Figure 8 behind the algorithm of graphics processing unit.The algorithmic approach that determines gray scale backlight has a lot, and some is to get this district's image maximum gray value, the maximum gray value is replaced with high gray 255 rank, and reduce gray scale backlight to the gray scale of former GTG value, is gray scale backlight.If for example the statistics image data finds that this district's maximum gray value is 200 rank, gray scale is 160nits, then first this GTG value is pulled to 255 GTGs, and reduces gray scale backlight, reduce making gray scale become 160nits, the corresponding gray scale backlight of this GTG can find its corresponding formula in the mode that measures in advance.This patent is not done restriction to the algorithm of gray scale backlight, can set as required certain algorithm.Graphics processing unit calculates the image greyscale that as shown in Figure 8 gray-scale value desirable backlight calculates the correspondence as shown in Figure 9 that makes new advances according to backlight control unit, and the gray-scale value that pixel is presented after backlight is constant.And this image frame transferred to display panels.Other three zones are no longer described in detail.The image data that liquid crystal display receives is after image is processed, and the GTG value after image is processed is more than or equal to former GTG value.GTG value curve after former GTG value correspondence image is as shown in figure 10 processed because the as a result raw video maximum gray that comes out is 200 rank, can become 255 GTGs as can be seen from Figure after image is processed.
Shown in the framework map that the image of Figure 11 is processed, picture memory is responsible for the input image data is stored and offer the image statistic unit, the image statistic unit is responsible for that each area image data gray-scale distribution is done statistics image statistic unit this statistics is offered graphics processing unit and backlight control unit, and backlight control unit distributes according to the image after adding up and calculates the gray-scale value desirable backlight in each zone.Graphics processing unit each desirable brightness value backlight in zone that image distributes and backlight control unit calculates after according to statistics calculates corresponding image data, and with data transmission to display panels.
Adopt technical scheme of the present invention, be not only applicable to direct-type backlight, also be applicable to the side entrance back mode, not only effectively solved the problem that prior art exists, adopt pulse wave formula backlight drive display panel, the smear when also significantly improving image and moving.
Claims (6)
1. a dynamic backlight driving method is used for display panels, it is characterized in that, comprises the steps:
Step 1: on vertical direction, be distinguished into a plurality of zones with backlight, and the backlight of each zone can independently be controlled back light source brightness;
Step 2: each regional image gray scale of statistical study redefines the gray scale backlight in each zone;
Step 3: according to the gray scale backlight that each zone redefines, recomputate the GTG of each regional image, the gray-scale value that pixel is presented after backlight is constant;
Step 4: display panels shows final image frame.
2. a kind of dynamic backlight driving method according to claim 1 is characterized in that: adopt the pulse wave formula to drive during backlight being lit in described each zone.
3. a kind of dynamic backlight driving method according to claim 1 is characterized in that: the frequency that is lit backlight in described each zone is identical with the frequency that the show image of described display panels upgrades.
4. a kind of dynamic backlight driving method according to claim 2 is characterized in that: width and the height-adjustable of the pulse wave that described pulse wave formula drives.
5. a kind of dynamic backlight driving method according to claim 2 is characterized in that: the backlight of described each zone lighted when stablizing in this regional liquid crystal reaction.
6. a kind of dynamic backlight driving method according to claim 1, it is characterized in that: the described GTG of each regional image that recomputates is more than or equal to former ash.
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| CN2012104238965A CN102890918A (en) | 2012-10-30 | 2012-10-30 | Dynamic backlight driving method |
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104318905A (en) * | 2014-09-19 | 2015-01-28 | 小米科技有限责任公司 | Method and device for adjusting screen backlight |
| CN104599642A (en) * | 2014-12-31 | 2015-05-06 | 小米科技有限责任公司 | Backlight control method and backlight control device |
| CN105047142A (en) * | 2015-09-01 | 2015-11-11 | 青岛海信电器股份有限公司 | Liquid crystal display brightness control method and device and liquid crystal display equipment |
| US10074318B2 (en) | 2015-09-01 | 2018-09-11 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| US10127867B2 (en) | 2015-09-01 | 2018-11-13 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| US10170057B2 (en) | 2015-10-16 | 2019-01-01 | Hisense Electric Co., Ltd. | Method and apparatus for controlling liquid crystal display brightness, and liquid crystal display device |
| US10181294B2 (en) | 2015-10-16 | 2019-01-15 | Hisense Electric Co., Ltd. | Method and apparatus for controlling liquid crystal display brightness, and liquid crystal display device |
| US10235946B2 (en) | 2015-09-01 | 2019-03-19 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| US10269308B2 (en) | 2015-09-17 | 2019-04-23 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| CN109767733A (en) * | 2019-03-29 | 2019-05-17 | 厦门天马微电子有限公司 | Display control method, display control unit and electronic equipment |
| CN110969980A (en) * | 2019-12-27 | 2020-04-07 | Tcl华星光电技术有限公司 | Display device and driving method thereof |
| CN111312142A (en) * | 2020-02-27 | 2020-06-19 | 福建华佳彩有限公司 | Driving method and device for improving image display quality |
| CN111341275A (en) * | 2019-12-31 | 2020-06-26 | Tcl集团股份有限公司 | Display control method, display device and storage medium |
| CN111354323A (en) * | 2020-04-26 | 2020-06-30 | 成都中电熊猫显示科技有限公司 | Display panel brightness control method and display device |
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Cited By (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104318905A (en) * | 2014-09-19 | 2015-01-28 | 小米科技有限责任公司 | Method and device for adjusting screen backlight |
| CN104599642B (en) * | 2014-12-31 | 2017-05-03 | 小米科技有限责任公司 | Backlight control method and backlight control device |
| CN104599642A (en) * | 2014-12-31 | 2015-05-06 | 小米科技有限责任公司 | Backlight control method and backlight control device |
| US10235946B2 (en) | 2015-09-01 | 2019-03-19 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| US9953587B2 (en) | 2015-09-01 | 2018-04-24 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| US10074318B2 (en) | 2015-09-01 | 2018-09-11 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| US10127867B2 (en) | 2015-09-01 | 2018-11-13 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| CN105047142A (en) * | 2015-09-01 | 2015-11-11 | 青岛海信电器股份有限公司 | Liquid crystal display brightness control method and device and liquid crystal display equipment |
| CN105047142B (en) * | 2015-09-01 | 2017-11-24 | 青岛海信电器股份有限公司 | Liquid crystal display brightness control method and device and liquid crystal display |
| US10269308B2 (en) | 2015-09-17 | 2019-04-23 | Hisense Electric Co., Ltd. | Apparatus and method for controlling liquid crystal display brightness, and liquid crystal display device |
| US10783836B2 (en) | 2015-10-16 | 2020-09-22 | Hisense Visual Technology Co., Ltd. | Method and apparatus for controlling liquid crystal display brightness, and liquid crystal display device |
| US10170057B2 (en) | 2015-10-16 | 2019-01-01 | Hisense Electric Co., Ltd. | Method and apparatus for controlling liquid crystal display brightness, and liquid crystal display device |
| US10181294B2 (en) | 2015-10-16 | 2019-01-15 | Hisense Electric Co., Ltd. | Method and apparatus for controlling liquid crystal display brightness, and liquid crystal display device |
| CN109767733A (en) * | 2019-03-29 | 2019-05-17 | 厦门天马微电子有限公司 | Display control method, display control unit and electronic equipment |
| CN109767733B (en) * | 2019-03-29 | 2021-01-05 | 厦门天马微电子有限公司 | Display control method, display control device and electronic equipment |
| CN110969980A (en) * | 2019-12-27 | 2020-04-07 | Tcl华星光电技术有限公司 | Display device and driving method thereof |
| WO2021128488A1 (en) * | 2019-12-27 | 2021-07-01 | Tcl华星光电技术有限公司 | Display apparatus and driving method therefor |
| CN111341275A (en) * | 2019-12-31 | 2020-06-26 | Tcl集团股份有限公司 | Display control method, display device and storage medium |
| CN111312142A (en) * | 2020-02-27 | 2020-06-19 | 福建华佳彩有限公司 | Driving method and device for improving image display quality |
| CN111312142B (en) * | 2020-02-27 | 2023-07-25 | 福建华佳彩有限公司 | Driving method and device for improving image display quality |
| CN111354323A (en) * | 2020-04-26 | 2020-06-30 | 成都中电熊猫显示科技有限公司 | Display panel brightness control method and display device |
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