CN102930830A - Method for improving non-uniformity of scanning backlight - Google Patents
Method for improving non-uniformity of scanning backlight Download PDFInfo
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- CN102930830A CN102930830A CN2012104240166A CN201210424016A CN102930830A CN 102930830 A CN102930830 A CN 102930830A CN 2012104240166 A CN2012104240166 A CN 2012104240166A CN 201210424016 A CN201210424016 A CN 201210424016A CN 102930830 A CN102930830 A CN 102930830A
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Abstract
The invention provides a method for improving non-uniformity of scanning backlight. The scanning backlight is scanned and driven through a backlight drive. The method comprises the following steps of: dividing the scanning backlight into n (n is not smaller than 2) regions to perform sequential scanning and driving; setting n independent current feedback control devices in the backlight drive, and utilizing an independent circuit for control in each region; and adjusting the circuit control of each region to enable the pulse brightness of lamp bars in the regions on two sides to be larger than that of other regions when the lamp bars are turned on. According to the method, the ignition brightness of each backlight region is controlled through a multichannel independent current control structure and driving the control of LED (Light Emitting Diode) independent current, the ignition brightness of the regions on the uppermost and lowest sides of the backlight is reinforced by adjusting and controlling the current values of corresponding channels when the scanning backlight scans the regions on the uppermost and lowest sides, and finally the optical interference among the backlight regions is realized, so that the uniformity of the integral backlight brightness can be to optimized.
Description
Technical field
The present invention relates to a kind of LCD backlight Drive Control Technique, relate in particular to a kind of method of improving the scanning backlight inequality.
Background technology
General liquid crystal display is for promoting MPRT(Moving Picture Response Time: the dynamic image reaction time) or under 3D uses, the scanning backlight module architectures of roughly can arranging in pairs or groups comes Improve Efficiency, scanning backlight is usually with the plural number zone that is distinguished into backlight, each occupied area in zone of scanning backlight is consistent haply, and controlling each regional LED, to light the time long too.Because optics phase mutual interference between the block backlight, the regional luminance of the most up and down both sides backlight that make is partially dark; And other zone line brightness are partially bright, Integral back luminance brightness homogeneity variation when causing the scanning backlight action.
Figure 1 shows that the synoptic diagram in backlight subarea territory, LCD backlight is distinguished into n(n 〉=2 with scanning backlight under scan-type is used) carry out P-SCAN under the individual regional architecture and drive.
Block1, the Block2 to Blockn of being numbered backlight in each zone, wherein Block1 and Blockn belong to the two side areas in backlight.
Figure 2 shows that the interference synoptic diagram of scanning backlight light, the dotted line among Fig. 2 is the brightness that regional backlight lamp bar is lighted, and solid line is that regional backlight lamp bar is lighted and seen through for the postrotational brightness of liquid crystal, and the light mean flow rate in Block1 and Blockn zone is La1 and Lan; Block2 is that La2 is to Lan-1 to the light mean flow rate in Block n-1 zone, because the disturbing factor of light causes the scanning backlight block to be lower than other zone leveling brightness La2 to Lan-1 in La1 and the Lan mean flow rate in Block1 and Blockn zone, the homogeneity in n zone is bad.
Existing general liquid crystal display collocation scanning backlight comes Improve Efficiency, and scanning backlight is distinguished into to several block of cells backlight usually.Because optics phase mutual interference between the block backlight causes the block brightness of both sides, up and down backlight partially dark; And other mesozone Block Brightness are partially bright, Integral back luminance brightness homogeneity variation when causing the scanning backlight action.
Summary of the invention
The present invention discloses the method for improving the scanning backlight inequality of the structure of a kind of hyperchannel separate current control, and to reach between the backlight area after the mutual interference of optics phase, Integral back luminance brightness homogeneity is optimized.
The invention provides a kind of method of improving the scanning backlight inequality, it is comprised the steps: by the backlight driver turntable driving
Scanning backlight is divided into n ((n 〉=2)) zone carries out the P-SCAN driving;
Be provided with n independently electric current feedback control device in the backlight driver, independently circuit control is adopted in each zone;
Regulate the circuit control of regional, so that the pulse brightness of the lamp bar of two side areas when lighting is higher than other zones.
Described electric current feedback control device control method is as follows:
The anodic bonding of each area lights bar is connected to DC voltage together afterwards, and this DC voltage is changed by DC-DC converting circuit;
The negative electrode of each area lights bar then is independently connected to backlight driver, and the negative electrode of each area lights bar is connected to first the source electrode of MOSFET, and the grid of MOSFET is connected to the output of comparer;
The positive pole input of comparer connects the accurate position of a DC reference voltage, and the negative pole input of comparer connects the accurate position of feedback voltage of a resistance;
The drain electrode of MOSFET is connected to a resistance;
Each area lights bar all independently arranges to transfer establishes resistance, and the electric current that two side areas is set is feedback the controlling resistance value less than other area resistance value.
The present invention is by the structure of hyperchannel separate current control, it is lower to see through the control of driving LED separate current, brightness when controlling each backlight area and lighting, when scanning backlight is just scanning block in both sides the most up and down, seeing through regulation and control increases the current value of corresponding passage, allow backlight the most up and down when the block of both sides is lighted brightness strengthen, finally reach between the block backlight after the mutual interference of optics phase, Integral back luminance brightness homogeneity is optimized, and the present invention can also be used for eliminating the Mura technology.
Description of drawings
Fig. 1 is the subregional synoptic diagram of scanning backlight;
Fig. 2 is the interference synoptic diagram in backlight subarea shown in Figure 1 territory;
Fig. 3 is the structural representation of scanning backlight of the present invention and backlight driver;
Fig. 4 is the principle schematic of the recirculation control device of backlight driver of the present invention.
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.
The present invention discloses a kind of method of improving the scanning backlight inequality, this method is used for LCD backlight under scan-type is used, as shown in Figure 3, scanning backlight is distinguished into n(n 〉=2) carry out P-SCAN under the individual zone and drive, Block1, the Block2 to Blockn of being numbered backlight in each zone, wherein Block1 and Blockn belong to the two side areas in backlight.
First regional Block1 of this scanning backlight and last regional Blockn have other zones (Block2-Blockn-1) Yi Bian only have about this two zone; And the extremely last penult of second area Block2 zone Blockn-1, these regional the right and lefts all have other zones backlight.
Be a direct current power supply by backlight driver (LED Converter) 10 input voltages, become backlight lamp bar 40 to drive required voltage voltage transitions through DC-DC circuit (DC/DC) 30, these lamp bar 40 driving voltages are connected to the anode (P) of each area lights bar backlight, and the anode of each area lights bar all links together.The negative electrode of each area lights bar then is independently connected to backlight driver 10, backlight driver 10 is respectively equipped with independently electric current feedback control device (Current Sink*n) 20 for each area lights bar, this electric current feedback control device (Current Sink*n) 20 is equivalent to the current mirror function, the size of current that determining area lamp bar flows through, the light on and off of also gated sweep formula block lamp backlight bar reach the accurate adjustment purpose of scan function backlight and brightness simultaneously.
Described lamp bar 40 is straight-down negative or side entering type lamp bar, and each regional backlight lamp bar can independently be controlled voltage or electric current.
The driver that this scanning backlight drives lamp bar 40 has several independently to feedback control channel, and each back coupling passage all can independently be controlled, and backlight driver (LED Converter) 10 can independently be regulated and control each regional lamp bar backlight.
Reaching the circuit size that each area lights bar flows through by this electric current feedback control device (Current Sink*n) 20 can independently control, and the electric current of middle two side areas Block1 backlight and Blockn is feedback controlling resistance value R1 and Rn less than other zones (Block2 to Blockn-1) resistance value R2 to Rn-1.Two side areas Block1 in backlight and the brightness of Blockn are by originally partially secretly increasing brightness because of turning R1 and Rn down, and other zone line brightness preservations are constant, so that Integral back luminance brightness homogeneity optimization when adjusting rear scanning backlight and moving.
First regional Block1 of scanning backlight and last regional Blockn, these two blocks adopt separate current or Current Control, pulse brightness when the backlight lamp bar of regulating these two zones (Block1 and Blockn) is lighted, so that the pulse brightness of the lamp bar in these two zones when lighting is higher than other zones, finally reach between the block backlight after the mutual interference of optics phase, Integral back luminance brightness homogeneity is optimized.
Electric current feedback control device (Current Sink) 20 is divided into 1 to n passage, and each passage is independently controlled corresponding Block 1~Block n.
The principle of the electric current feedback control device of backlight driver (Current Sink) as shown in Figure 4, the anodic bonding of each area lights bar is connected to DC voltage (Vout) together afterwards, and this DC voltage (Vout) can be changed formation by DC-DC converting circuit (DC/DC) 30.The negative electrode of each area lights bar then is independently connected to backlight driver 10, the negative electrode of each area lights bar is connected to first the source electrode of MOSFET, the grid of MOSFET is connected to the output of comparer (Buffer), and the positive pole input of comparer (Buffer) connects the accurate position of a DC reference voltage (Vref); The negative pole input of comparer (Buffer) connects the accurate position of feedback voltage (VA) of a resistance R, and the drain electrode of MOSFET is connected to a resistance R.Each area lights bar all independently arranges to transfer establishes resistance R, and the lamp bar arranges R1 in the first area; At second area lamp bar R2 is set; In the end the area lights bar arranges Rn.The present invention is under scanning backlight is used, if R1 and the Rn both sides block of gated sweep formula in backlight respectively can be turned the resistance value of R1 and Rn down the resistance value that arrives Rn-1 in R2.
By the resistance value of R1 and Rn being turned down the resistance value in R2 to Rn-1, so that the brightness of the two side areas Block1 in backlight and Blockn is by originally partially secretly because turning R1 down and Rn increases brightness, other zone line brightness preservations are constant, so that adjust Integral back luminance brightness homogeneity optimization when scanning backlight moves afterwards.
The present invention is by the structure of hyperchannel separate current control, it is lower to see through the control of driving LED separate current, brightness when controlling each backlight area and lighting, when scanning backlight is just scanning block in both sides the most up and down, seeing through regulation and control increases the current value of corresponding passage, allow backlight the most up and down when the block of both sides is lighted brightness strengthen, finally reach between the block backlight after the mutual interference of optics phase, Integral back luminance brightness homogeneity is optimized, and the present invention can also be used for eliminating the Mura technology.
Claims (9)
1. method of improving the scanning backlight inequality, it be is characterized in that by the backlight driver turntable driving, comprises the steps:
Scanning backlight is divided into n ((n 〉=2)) zone carries out the P-SCAN driving;
Be provided with n independently electric current feedback control device in the backlight driver, independently circuit control is adopted in each zone;
Regulate the circuit control of regional, so that the pulse brightness of the lamp bar of two side areas when lighting is higher than other zones.
2. the method for improving the scanning backlight inequality according to claim 1 is characterized in that: the electric current of two side areas is feedback the controlling resistance value less than other area resistance value.
3. the method for improving the scanning backlight inequality according to claim 1, it is characterized in that: the electric current feedback control device is divided into 1 to n passage, and each passage is independently controlled each self-corresponding zone.
4. the method for improving the scanning backlight inequality according to claim 1, it is characterized in that: on one side first zone and last zone about only have other zones arranged, second area to the last the right and left in penult zone all has other zones backlight.
5. the method for improving the scanning backlight inequality according to claim 1, it is characterized in that: described backlight driver input voltage is a direct current power supply, becomes backlight lamp bar to drive required voltage voltage transitions through DC-DC circuit.
6. the method for improving the scanning backlight inequality according to claim 1, it is characterized in that: the anode of each area lights bar all links together, and the negative electrode of each area lights bar is independently connected to backlight driver.
7. the method for improving the scanning backlight inequality according to claim 1, it is characterized in that: described lamp bar is straight-down negative or side entering type lamp bar.
8. according to claim 1 to the 7 described methods of improving the scanning backlight inequality, it is characterized in that: the voltage of the backlight lamp bar that each is regional or electric current are independently controlled by the electric current feedback control device.
9. the method for improving the scanning backlight inequality according to claim 1, it is characterized in that: described electric current feedback control device control method is as follows:
The anodic bonding of each area lights bar is connected to DC voltage together afterwards, and this DC voltage is changed by DC-DC converting circuit;
The negative electrode of each area lights bar then is independently connected to backlight driver, and the negative electrode of each area lights bar is connected to first the source electrode of MOSFET, and the grid of MOSFET is connected to the output of comparer;
The positive pole input of comparer connects the accurate position of a DC reference voltage, and the negative pole input of comparer connects the accurate position of feedback voltage of a resistance;
The drain electrode of MOSFET is connected to a resistance;
Each area lights bar all independently arranges to transfer establishes resistance, and the electric current that two side areas is set is feedback the controlling resistance value less than other area resistance value.
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Citations (5)
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CN1873504A (en) * | 2005-05-31 | 2006-12-06 | 三星电子株式会社 | Backlight system and liquid crystal display employing the same |
US20070091036A1 (en) * | 2005-10-20 | 2007-04-26 | Mingkwang Han | Apparatus and method for regulating white LEDs |
CN101197109A (en) * | 2007-04-19 | 2008-06-11 | 友达光电股份有限公司 | Current feedback and compensation circuit, led driving device and backlight system |
CN101772237A (en) * | 2008-12-31 | 2010-07-07 | 凹凸电子(武汉)有限公司 | Circuit for controlling light sources, method and display system |
US20110205250A1 (en) * | 2010-02-23 | 2011-08-25 | Samsung Mobile Display Co., Ltd. | Organic Light Emitting Display and Driving Method Thereof |
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Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1873504A (en) * | 2005-05-31 | 2006-12-06 | 三星电子株式会社 | Backlight system and liquid crystal display employing the same |
US20070091036A1 (en) * | 2005-10-20 | 2007-04-26 | Mingkwang Han | Apparatus and method for regulating white LEDs |
CN101197109A (en) * | 2007-04-19 | 2008-06-11 | 友达光电股份有限公司 | Current feedback and compensation circuit, led driving device and backlight system |
CN101772237A (en) * | 2008-12-31 | 2010-07-07 | 凹凸电子(武汉)有限公司 | Circuit for controlling light sources, method and display system |
US20110205250A1 (en) * | 2010-02-23 | 2011-08-25 | Samsung Mobile Display Co., Ltd. | Organic Light Emitting Display and Driving Method Thereof |
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