WO2015010456A1 - Led背光亮度的调整方法 - Google Patents

Led背光亮度的调整方法 Download PDF

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Publication number
WO2015010456A1
WO2015010456A1 PCT/CN2014/070673 CN2014070673W WO2015010456A1 WO 2015010456 A1 WO2015010456 A1 WO 2015010456A1 CN 2014070673 W CN2014070673 W CN 2014070673W WO 2015010456 A1 WO2015010456 A1 WO 2015010456A1
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Prior art keywords
led
brightness
current
value
led backlight
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PCT/CN2014/070673
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English (en)
French (fr)
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文东
秦建设
李建强
杨勇
张海鹰
左德祥
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深圳Tcl新技术有限公司
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Priority to EP14829741.9A priority Critical patent/EP3026986A4/en
Priority to US14/894,427 priority patent/US9532426B2/en
Publication of WO2015010456A1 publication Critical patent/WO2015010456A1/zh

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0613—The adjustment depending on the type of the information to be displayed
    • G09G2320/062—Adjustment of illumination source parameters
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G09G2320/0633—Adjustment of display parameters for control of overall brightness by amplitude modulation of the brightness of the illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G09G2320/064—Adjustment of display parameters for control of overall brightness by time modulation of the brightness of the illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0666—Adjustment of display parameters for control of colour parameters, e.g. colour temperature
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/021—Power management, e.g. power saving

Definitions

  • the invention relates to the field of liquid crystal television technology, and in particular relates to a method for adjusting the brightness of an LED backlight.
  • the adjustment of the LED backlight brightness of the LCD TV usually adopts the PWM dimming mode, that is, the current through the LED lamp is kept unchanged, and the duty ratio of the PWM wave is changed, so that the LED light of the backlight strip is turned on and the off time is followed. Change to achieve the purpose of adjusting the brightness of the backlight.
  • the duty cycle of the PWM is 100%, the LED backlight strip is always on, corresponding to the maximum backlight brightness of the TV; gradually reducing the duty cycle of the PWM wave, the backlight brightness is also gradually reduced.
  • the PWM dimming method has the following disadvantages: 1. When the current of the LED lamp is fixed to the current at the maximum brightness, the LED luminous efficiency is low, and the backlight loss is large; 2.
  • the main object of the present invention is to provide a method for adjusting the brightness of an LED backlight, which can improve the luminous efficiency of the LED, reduce the backlight loss, and reduce the noise generated by the LED driving circuit.
  • the invention provides a method for adjusting brightness of an LED backlight, comprising the following steps:
  • the PWM duty ratio is kept at a maximum value, and the brightness of the LED backlight is adjusted by adjusting the conduction current of the LED;
  • the on-current of the LED is kept constant, and the brightness of the LED backlight is adjusted by adjusting the PWM duty ratio to vary between the maximum value and the minimum value.
  • the preset value is any value within a range of 36% to 84% of the maximum brightness of the LED backlight.
  • the maximum value of the PWM duty cycle is a value in the range of 80% to 100%.
  • the preset value is a brightness value of the LED backlight corresponding to when the ON current of the LED is at a predetermined value, and the predetermined value of the ON current of the LED is determined by the color coordinate change characteristic and the luminous efficiency of the LED.
  • the predetermined value of the LED on current is any value within a range of 30% to 80% of the maximum value of the on current of the LED during actual operation.
  • the predetermined value of the LED on current is 42% of the maximum value of the on current of the LED when actually operating.
  • the preset value is any value within a range of 36% to 84% of the maximum brightness of the LED backlight.
  • the preset value is 48.3% of the maximum brightness of the LED backlight.
  • the step of adjusting the brightness of the LED backlight by adjusting the conduction current of the LED backlight includes:
  • the PWM duty ratio is kept at a maximum value, and the on-current of the LED is increased to the on-current of the LED during actual operation.
  • the maximum value when the brightness of the LED backlight is reduced to a preset value, the PWM duty ratio is maintained at a maximum value, and the on current of the LED is reduced to a predetermined value of the on current.
  • the maximum value of the PWM duty cycle is a value in the range of 80% to 100%.
  • the minimum value of the PWM duty ratio is a value in the range of 0% to 30%.
  • the step of adjusting the brightness of the LED backlight by adjusting the PWM duty ratio between the maximum value and the minimum value includes: :
  • the current LED backlight brightness is not higher than a preset value
  • the on-current of the LED is kept constant to a predetermined value of the on-current, and the PWM duty ratio is decreased.
  • the ON current of the LED is kept constant to a predetermined value of the ON current, and the PWM duty ratio is increased to a maximum value.
  • the minimum value of the PWM duty ratio is a value in the range of 0% to 30%.
  • the method for adjusting the brightness of the LED backlight of the present invention selects PWM dimming or conducting current dimming according to the backlight brightness of the current LED, so that the conduction current of the LED is not always maintained at the maximum value, thereby greatly improving the LED.
  • Luminous efficiency reduces backlight loss.
  • the on-current dimming ie, analog dimming
  • the analog dimming can avoid the noise generated by the LED driving circuit;
  • the PWM modulation is adopted. Light, at this time, the on-current of the LED is at a predetermined value and not the maximum value, and the noise generated by the LED driving circuit can also be avoided.
  • FIG. 1 is a schematic flow chart of an embodiment of a method for adjusting brightness of an LED backlight according to the present invention
  • FIG. 4 is a graph of LED backlight brightness adjustment when the LED on current is predetermined to select 42% of the maximum on current of the LED when the LED is actually operated.
  • Fig. 5 is a comparison diagram of luminous efficiency of an LED.
  • FIG. 1 is a schematic flow chart of an embodiment of a method for adjusting brightness of an LED backlight according to the present invention
  • FIG. 2 is a graph showing changes in color coordinate characteristics of the LED
  • FIG. 3 is a graph showing changes in luminous efficiency of the LED.
  • Step S10 if the brightness of the current LED backlight is higher than a preset value, the PWM duty ratio is kept at a maximum value, and the brightness of the LED backlight is adjusted by adjusting the conduction current of the LED;
  • the maximum value of the PWM duty ratio is preferably 100%, 99%, and may be any value in the range of 80% to 100%.
  • the preset value is a brightness value of the LED backlight corresponding to the on current of the LED being at a predetermined value, and the predetermined value of the LED on current is determined by the color coordinate change characteristic and the luminous efficiency of the LED, and the setting standard is Yes: It can improve the luminous efficiency without changing the color coordinates too much and affecting the picture quality.
  • the color coordinate x is basically unchanged, and the color coordinate y varies by ⁇ 0.003.
  • the variation range is small, and has no effect on the image viewing quality.
  • the predetermined values of the on-current may be different due to different LED color coordinate variation characteristics (for example, there may be 41%, 43%, etc.), the backlight brightness preset value will also be different depending on the predetermined value of the on current.
  • the above 42% is set based on the maximum value of the on-current of the LED when the actual operation of the LED is equal to the rated current of the LED, and the maximum value of the on-current may be greater or smaller than the rated value of the LED in consideration of the actual operation of the LED. Current (for example, 1.2 times rated current or 0.5 times rated current).
  • the maximum value of the on-current of the LED during actual operation may be only 60% of the rated current of the LED.
  • the predetermined value of the LED conduction current selects 42% of the rated current of the LED, which is actually the conduction current of the LED during actual operation. 70%. Therefore, the predetermined value of the LED on current can be selected according to different conditions within a range of 30% to 80% of the maximum value of the on current of the LED during actual operation.
  • the preset value of the brightness of the backlight is about a value ranging from 36% to 84% of the maximum brightness of the LED backlight.
  • adjusting the backlight brightness of the LED includes the following steps of increasing the brightness of the LED backlight to the maximum brightness and reducing the brightness of the LED backlight to a preset value:
  • keeping the PWM duty cycle at the maximum value increases the on-current of the LED to the maximum value of the on-current when the LED actually operates, thereby increasing the brightness of the LED backlight from the current LED backlight brightness to the brightness. Maximum value.
  • the PWM duty ratio is also kept at a maximum value, and the on current of the LED is reduced to a predetermined value of the on current, thereby reducing the brightness of the LED backlight from the current LED backlight brightness to the default value.
  • step S20 if the current LED backlight brightness is not higher than a preset value, the on-current of the LED is kept constant, and the brightness of the LED backlight is adjusted by adjusting the PWM duty ratio to vary between the maximum value and the minimum value.
  • the minimum value of the above PWM duty ratio is preferably 10%, and may be any value in the range of 0% to 30%.
  • adjusting the backlight brightness of the LED includes the following steps of reducing the brightness of the LED backlight to the minimum value of the brightness and increasing the brightness of the LED backlight to a preset value:
  • keeping the on current of the LED constant is a predetermined value of the on current, and reducing the PWM duty ratio to a minimum value, thereby reducing the brightness of the LED backlight from the current LED backlight brightness to the minimum brightness. value.
  • the ON current of the LED is also kept constant to a predetermined value of the on current, and the PWM duty ratio is increased to a maximum value, thereby increasing the brightness of the LED backlight from the current LED backlight brightness to default value.
  • FIG. 4 is a graph of LED backlight brightness adjustment when the LED on current is preset to select 42% of the maximum on current of the LED when the LED is actually operated.
  • the on-current of the LED is kept constant at 42%, and the PWM duty ratio is increased from 0% to 100%, thereby increasing the brightness of the LED backlight from 0% to 48.3%; continue to increase the backlight brightness, keep the PWM duty cycle 100%, increase the LED's on current from 42% to 100%, thereby increasing the brightness of the LED backlight from 48.3% to 100%.
  • the PWM duty cycle is kept at 100%, and the on-current of the LED is reduced from 100% to 42%, thereby reducing the brightness of the LED backlight from 100% to 48.3. %;
  • the ON current of the LED is kept constant at 42%, and the PWM duty ratio is reduced from 100% to 0%, thereby reducing the brightness of the LED backlight from 48.3% to 0%.
  • FIG. 5 is a comparison diagram of luminous efficiency of LEDs.
  • C1 represents the luminous efficiency of the LED which is only PWM dimming in the prior art, and is maintained at 100%;
  • C2 represents the luminous efficiency of the mixed dimming LED of the present invention, which is increased from 100% to 115%. It can be seen that the method for adjusting the brightness of the LED backlight of the present invention greatly improves the luminous efficiency of the LED.
  • the method for adjusting the brightness of the LED backlight of the present invention selects PWM dimming or conducting current dimming according to the backlight brightness of the current LED, so that the conduction current of the LED is not always maintained at the maximum value, thereby greatly improving the LED.
  • Luminous efficiency reduces backlight loss.
  • the on-current dimming ie, analog dimming
  • the analog dimming can avoid the noise generated by the LED driving circuit;
  • the PWM modulation is adopted. Light, at this time, the on-current of the LED is at a predetermined value and not the maximum value, and the noise generated by the LED driving circuit can also be avoided.

Abstract

一种LED背光亮度的调整方法，包括以下步骤：如当前LED背光亮度高于预设值，则保持PWM占空比为最大值，通过调整LED的导通电流来调整LED背光的亮度（S10）；如当前LED背光亮度不高于预设值，则保持LED的导通电流恒定，通过调整PMW占空比在最大值与最小值之间变化来调整LED背光的亮度（S20）。本方法能够提高LED的发光效率，减小背光损耗，降低LED驱动电路产生的噪声。

Description

LED背光亮度的调整方法
技术领域
本发明涉及到液晶电视技术领域，特别涉及到一种LED背光亮度的调整方法。　　　
背景技术
　　　目前，液晶电视机的LED背光亮度的调整通常采用PWM调光方式，即保持通过LED灯的电流不变，改变PWM波的占空比，使背光灯条的LED灯导通、截止时间随之改变，从而达到调整背光亮度的目的。当PWM的占空比为100%时，LED背光灯条常亮，此时对应电视机的最大背光亮度；逐步降低PWM波的占空比，背光亮度也随之逐步降低。然而，PWM调光方式具有如下缺点：1、通过LED灯的电流固定为最大亮度时的电流，使LED发光效率较低、背光的损耗较大；2、通过LED灯的电流固定为最大亮度时的电流，此情况下，如果 PWM 的信号频率正好落在 100Hz 到 20kHz 人耳听觉频率范围内时，LED 驱动电路周围的电感和输出电容就会产生较大的噪声。 　　　
发明内容
　　　本发明的主要目的为提供一种LED背光亮度的调整方法，能够提高LED的发光效率，减小背光损耗，降低LED驱动电路产生的噪声。
　　　本发明提供一种LED背光亮度的调整方法，包括以下步骤：
　　　如当前LED背光亮度高于预设值，则保持PWM占空比为最大值，通过调整LED的导通电流来调整LED背光的亮度；
　　　如当前LED背光亮度不高于预设值，则保持LED的导通电流恒定，通过调整PWM占空比在最大值与最小值之间变化来调整LED背光的亮度。
　　　优选地，所述预设值为LED背光的亮度最大值的36%~84%范围内的任意数值。
　　　优选地，所述PWM占空比的最大值为80%~100%范围内的数值。
　　　优选地，所述预设值为LED的导通电流处于预定值时所对应的LED背光的亮度值，所述LED的导通电流的预定值由LED的色坐标变化特性和发光效率决定。
　　　优选地，所述LED导通电流的预定值为LED实际工作时导通电流的最大值的30%~80%范围内的任意数值。
　　　优选地，所述LED导通电流的预定值为LED实际工作时导通电流的最大值的42%。
　　　优选地，所述预设值为LED背光的亮度最大值的36%~84%范围内的任意数值。
　　　优选地，所述预设值为LED背光的亮度最大值的48.3%。
　　　优选地，所述如当前LED背光亮度高于预设值，则保持PWM占空比为最大值，通过调整LED背光的导通电流来调整LED背光的亮度的步骤包括：
　　　如当前LED背光亮度高于预设值，在将LED背光的亮度增大至亮度最大值时，保持PWM占空比为最大值，将LED的导通电流增大至LED实际工作时导通电流的最大值；在将LED背光的亮度减小至预设值时，保持PWM占空比为最大值，将LED的导通电流减小至所述导通电流的预定值。
　　　优选地，所述PWM占空比的最大值为80%~100%范围内的数值。
　　　优选地，所述PWM占空比的最小值为0%~30%范围内的数值。
　　　优选地，所述如当前LED背光亮度不高于预设值，则保持LED的导通电流恒定，通过调整PWM占空比在最大值与最小值之间变化来调整LED背光的亮度的步骤包括：
　　　如当前LED背光亮度不高于预设值，在将LED背光的亮度减小至亮度最小值时，保持LED的导通电流恒定为所述导通电流的预定值，将PWM占空比减小至最小值；在将LED背光的亮度增大至预设值时，保持LED的导通电流恒定为所述导通电流的预定值，将PWM占空比增大至最大值。
　　　优选地，所述PWM占空比的最小值为0%~30%范围内的数值。　　　
　　　相较于现有技术，本发明LED背光亮度的调整方法根据当前LED的背光亮度选择PWM调光或者导通电流调光，使得LED的导通电流并非一直保持在最大值，大大提高了LED的发光效率，减小了背光损耗。另外，在LED背光亮度高于预设值时采用导通电流调光(即模拟调光)，模拟调光可以避免LED驱动电路产生噪声；在LED背光亮度不高于预设值时采用PWM调光，此时LED的导通电流处于预定值并非最大值，也可以避免LED驱动电路产生噪声。　
附图说明
图1为本发明LED背光亮度的调整方法实施例的流程示意图；
图2为LED的色坐标变化特性的曲线图；
图3为LED的发光效率变化特性的曲线图；
图4为LED导通电流预定值选择LED实际工作时导通电流最大值的42%时LED背光亮度调整的曲线图。
图5是LED的发光效率的对比图。
本发明目的的实现、功能特点及优点将结合实施例，参照附图做进一步说明。　　　
具体实施方式
应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
参照图1至图3，图1为本发明LED背光亮度的调整方法实施例的流程示意图；图2为LED的色坐标变化特性的曲线图；图3为LED的发光效率变化特性的曲线图。
本实施例所提供的LED背光亮度的调整方法，包括：
步骤S10，如当前LED背光亮度高于预设值，则保持PWM占空比为最大值，通过调整LED的导通电流来调整LED背光的亮度；
　　　本实施例中，所述PWM占空比的最大值优选100%、99%，可为80%~100%范围内的任意数值。
　　　所述预设值为LED的导通电流处于预定值时所对应的LED背光的亮度值，所述LED导通电流的预定值是由LED的色坐标变化特性和发光效率决定的，设定标准是：既能提高发光效率，又不使色坐标变化太大而影响画面品质。
　　　图2中，LED导通电流为100%时，达到额定电流。如图2和图3所示，LED的导通电流减小，其发光效率会增高，色坐标x变化比较小，但色坐标y在导通电流低于LED实际工作时导通电流最大值(此处假设LED实际工作时导通电流最大值=LED的额定电流)的42%后会明显变高。从图2可以看出，当LED的导通电流在LED实际工作时导通电流最大值的100%~42%之间变化时，整体背光灯条的色坐标x和色坐标y变化都较小，色坐标x基本不变，色坐标y变化量<0.003，该变化范围很小，对图像观看质量无影响；当导通电流从42%进一步降低时，色坐标y变化速度明显加快，开始对图像的观看质量产生明显影响。故本实施例中，所述LED导通电流的预定值为LED实际工作时导通电流最大值的42%，此时从图3可以看出，LED的发光效率为115%，通过42%*1.15=48.3%计算可以得到，上述背光亮度的预设值为LED背光的亮度最大值的48.3%。
　　　不过，在上述LED实际工作时导通电流最大值等于LED的额定电流的条件下，由于不同的LED色坐标变化特性不同，所以导通电流预定值也会有差异(例如有可能为41%、43%等)，背光亮度预设值也会对应地因导通电流预定值不同而不同。另外，上述的42%是基于LED实际工作时导通电流的最大值等于LED的额定电流的条件下设定的，考虑到LED实际工作时导通电流的最大值有可能大于或者小于LED的额定电流(例如，1.2倍的额定电流或者0.5倍的额定电流)。举例来说，LED实际工作时导通电流的最大值可能只是LED额定电流的60%，此时LED导通电流的预定值选择LED额定电流的42%，实际为LED实际工作时导通电流的70%。因此，所述LED导通电流的预定值可以根据不同情况选择LED实际工作时导通电流的最大值的30%~80%范围内的数值。相应的，所述背光亮度的预设值大约选择LED背光的亮度最大值的36%~84%范围内的数值。
　　所述步骤S10中，调整LED的背光亮度包括以下将LED背光的亮度增大至亮度最大值和将LED背光的亮度减小至预设值两种情况：
　　　一、将LED背光的亮度增大至亮度最大值：
　　　在这种情况下，保持PWM占空比为最大值，将LED的导通电流增大至LED实际工作时导通电流的最大值，从而将LED背光的亮度从当前LED背光亮度增大至亮度最大值。
　　　二、将LED背光的亮度减小至预设值：
　　　在这种情况下，同样保持PWM占空比为最大值，将LED的导通电流减小至所述导通电流的预定值，从而将LED背光的亮度从当前LED背光亮度减小至所述预设值。
　　　步骤S20，如当前LED背光亮度不高于预设值，则保持LED的导通电流恒定，通过调整PWM占空比在最大值与最小值之间变化来调整LED背光的亮度。上述PWM占空比的最小值优选10%，可为0%到30%范围内的任意数值。
　　所述步骤S20中，调整LED的背光亮度包括以下将LED背光的亮度减小至亮度最小值和将LED背光的亮度增大至预设值两种情况：
　　　一、将LED背光的亮度减小至亮度最小值：
　　　在这种情况下，保持LED的导通电流恒定为所述导通电流的预定值，将PWM占空比减小至最小值，从而将LED背光的亮度从当前LED背光亮度减小至亮度最小值。
　　　二、将LED背光的亮度增大至预设值：
　　　在这种情况下，则同样保持LED的导通电流恒定为所述导通电流的预定值，将PWM占空比增大至最大值，从而将LED背光的亮度从当前LED背光亮度增大至预设值。
　　　请参阅图4，图4为LED导通电流预定值选择LED实际工作时导通电流最大值的42%时LED背光亮度调整的曲线图。
　　　当LED背光的亮度从0%开始调高时，保持LED的导通电流恒定为42%，将PWM占空比从0%增大至100%，从而将LED背光的亮度从0%增大至48.3%；继续调高背光亮度时，保持PWM占空比为100%，将LED的导通电流从42%增大至100%，从而将LED背光的亮度从48.3%增大至100%。
　　　当LED背光的亮度从100%开始调低时，保持PWM占空比为100%，将LED的导通电流从100%减小至42%，从而将LED背光的亮度从100%减小至48.3%；继续调低背光亮度时，保持LED的导通电流恒定为42%，将PWM占空比从100%减小至0%，从而将LED背光的亮度从48.3%减小至0%。
　　　图4只是举例说明，以便于理解，PWM占空比的最大值并非一定是100%，最小值也并非一定是0%，相应的，背光亮度的最大值也并非一定值100%，最小值也并非一定是0%。
　　　请参阅图5，图5是LED的发光效率的对比图。图中，C1表示现有技术中只采用PWM调光的LED的发光效率，保持在100%；C2表示本发明混合调光的LED的发光效率，从100%升高至115%。可见，本发明LED背光亮度的调整方法使得LED的发光效率大大提高。
　　　相较于现有技术，本发明LED背光亮度的调整方法根据当前LED的背光亮度选择PWM调光或者导通电流调光，使得LED的导通电流并非一直保持在最大值，大大提高了LED的发光效率，减小了背光损耗。另外，在LED背光亮度高于预设值时采用导通电流调光(即模拟调光)，模拟调光可以避免LED驱动电路产生噪声；在LED背光亮度不高于预设值时采用PWM调光，此时LED的导通电流处于预定值并非最大值，也可以避免LED驱动电路产生噪声。
以上所述仅为本发明的优选实施例，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本发明的专利保护范围。

Claims (13)

  1. 一种LED背光亮度的调整方法，其特征在于，包括以下步骤：
    　　　如当前LED背光亮度高于预设值，则保持PWM占空比为最大值，通过调整LED的导通电流来调整LED背光的亮度；
    　　　如当前LED背光亮度不高于预设值，则保持LED的导通电流恒定，通过调整PWM占空比在最大值与最小值之间变化来调整LED背光的亮度。
  2. 根据权利要求1所述的LED背光亮度的调整方法，其特征在于，所述预设值为LED背光的亮度最大值的36%~84%范围内的任意数值。
  3. 根据权利要求1所述的LED背光亮度的调整方法，其特征在于，所述PWM占空比的最大值为80%~100%范围内的数值。
  4. 根据权利要求1所述的LED背光亮度的调整方法，其特征在于，所述预设值为LED的导通电流处于预定值时所对应的LED背光的亮度值，所述LED的导通电流的预定值由LED的色坐标变化特性和发光效率决定。
  5. 根据权利要求4所述的LED背光亮度的调整方法，其特征在于，所述LED导通电流的预定值为LED实际工作时导通电流的最大值的30%~80%范围内的任意数值。
  6. 根据权利要求5所述的LED背光亮度的调整方法，其特征在于，所述LED导通电流的预定值为LED实际工作时导通电流的最大值的42%。
  7. 根据权利要求4所述的LED背光亮度的调整方法，其特征在于，所述预设值为LED背光的亮度最大值的36%~84%范围内的任意数值。
  8. 根据权利要求7所述的LED背光亮度的调整方法，其特征在于，所述预设值为LED背光的亮度最大值的48.3%。
  9. 根据权利要求4所述的LED背光亮度的调整方法，其特征在于，所述如当前LED背光亮度高于预设值，则保持PWM占空比为最大值，通过调整LED背光的导通电流来调整LED背光的亮度的步骤包括：
    　　　如当前LED背光亮度高于预设值，在将LED背光的亮度增大至亮度最大值时，保持PWM占空比为最大值，将LED的导通电流增大至LED实际工作时导通电流的最大值；在将LED背光的亮度减小至预设值时，保持PWM占空比为最大值，将LED的导通电流减小至所述导通电流的预定值。
  10. 根据权利要求4所述的LED背光亮度的调整方法，其特征在于，所述PWM占空比的最大值为80%~100% 范围内的数值。
  11. 根据权利要求4所述的LED背光亮度的调整方法，其特征在于，所述PWM占空比的最小值为0%~30%范围内的数值。
  12. 根据权利要求4所述的LED背光亮度的调整方法，其特征在于，所述如当前LED背光亮度不高于预设值，则保持LED的导通电流恒定，通过调整PWM占空比在最大值与最小值之间变化来调整LED背光的亮度的步骤包括：
    　　　如当前LED背光亮度不高于预设值，在将LED背光的亮度减小至亮度最小值时，保持LED的导通电流恒定为所述导通电流的预定值，将PWM占空比减小至最小值；在将LED背光的亮度增大至预设值时，保持LED的导通电流恒定为所述导通电流的预定值，将PWM占空比增大至最大值。
  13. 根据权利要求12所述的LED背光亮度的调整方法，其特征在于，所述PWM占空比的最小值为0%~30%范围内的数值。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113326029A (zh) * 2021-05-13 2021-08-31 深圳恒之源技术股份有限公司 一种led灯具亮度调节方法、系统及计算机可读存储介质

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10665181B2 (en) * 2017-06-28 2020-05-26 Apple Inc. Backlights with dynamic dimming ranges
CN103415109B (zh) * 2013-07-22 2015-09-30 深圳Tcl新技术有限公司 Led背光亮度的调整方法
CN104766567A (zh) * 2015-03-18 2015-07-08 康佳集团股份有限公司 一种led背光驱动电路及其亮度调节方法
KR102415744B1 (ko) * 2015-06-03 2022-07-04 삼성전자주식회사 인접한 두 휘도 단계 사이에 새로운 휘도 단계를 생성하는 방법 및 전자 장치
CN105187749B (zh) 2015-09-25 2018-08-31 深圳创维－Rgb电子有限公司 一种电视背光驱动装置及其驱动方法
CN105187124B (zh) * 2015-09-28 2018-05-18 中国人民解放军信息工程大学 一种基于背光调制的信息传输方法和装置
CN105810156B (zh) * 2016-05-25 2018-06-01 武汉华星光电技术有限公司 背光调节方法及背光调节电路
CN106205503B (zh) * 2016-08-01 2019-08-09 青岛海信电器股份有限公司 一种led亮度调节方法和装置
CN106793252A (zh) * 2016-11-25 2017-05-31 上海航空电器有限公司 一种电压和占空比双控的led照明调光方法
CN106658840A (zh) * 2016-12-09 2017-05-10 上海航空电器有限公司 一种用于控制飞机led指示灯亮度的方法和装置
CN106710536A (zh) * 2017-03-10 2017-05-24 广东欧珀移动通信有限公司 调整显示屏亮度的方法、装置及终端
CN109389947B (zh) * 2017-08-09 2021-05-11 群创光电股份有限公司 显示设备
US10986707B2 (en) 2017-08-09 2021-04-20 Innolux Corporation Display device
CN108039152B (zh) * 2017-12-14 2020-11-13 深圳Tcl新技术有限公司 背光驱动控制方法、设备及计算机可读存储介质
CN113889037B (zh) * 2021-11-12 2023-02-17 京东方科技集团股份有限公司 显示面板及其驱动方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060170370A1 (en) * 2005-02-02 2006-08-03 Patent-Treuhand-Gesellschaft Fur Elektrisch Gluhlampen Mbh Method and system for dimming light sources
CN101137262A (zh) * 2006-08-30 2008-03-05 精工爱普生株式会社 发光元件驱动装置及其驱动方法
CN101836505A (zh) * 2007-10-25 2010-09-15 松下电工株式会社 Led调光装置
CN103167688A (zh) * 2011-12-09 2013-06-19 松下电器产业株式会社 点亮装置
CN103415109A (zh) * 2013-07-22 2013-11-27 深圳Tcl新技术有限公司 Led背光亮度的调整方法

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4686644B2 (ja) * 2009-07-07 2011-05-25 シャープ株式会社 液晶表示装置
US8872810B2 (en) * 2010-10-12 2014-10-28 National Semiconductor Corporation Combined digital modulation and current dimming control for light emitting diodes
CN102612227B (zh) * 2012-03-09 2014-02-12 矽力杰半导体技术(杭州)有限公司 一种混合调光电路及其混合调光方法
CN102708801A (zh) * 2012-06-06 2012-10-03 天津三星电子有限公司 一种显示终端背光亮度的控制方法及其显示终端
CN102843828B (zh) * 2012-08-06 2014-05-14 电子科技大学 一种pwm调制电路
CN202855273U (zh) * 2012-09-13 2013-04-03 上海江森自控汽车电子有限公司 基于差分反馈的lcd显示屏背光恒流驱动电路

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060170370A1 (en) * 2005-02-02 2006-08-03 Patent-Treuhand-Gesellschaft Fur Elektrisch Gluhlampen Mbh Method and system for dimming light sources
CN101137262A (zh) * 2006-08-30 2008-03-05 精工爱普生株式会社 发光元件驱动装置及其驱动方法
CN101836505A (zh) * 2007-10-25 2010-09-15 松下电工株式会社 Led调光装置
CN103167688A (zh) * 2011-12-09 2013-06-19 松下电器产业株式会社 点亮装置
CN103415109A (zh) * 2013-07-22 2013-11-27 深圳Tcl新技术有限公司 Led背光亮度的调整方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113326029A (zh) * 2021-05-13 2021-08-31 深圳恒之源技术股份有限公司 一种led灯具亮度调节方法、系统及计算机可读存储介质
CN113326029B (zh) * 2021-05-13 2024-03-22 深圳恒之源技术股份有限公司 一种led灯具亮度调节方法、系统及计算机可读存储介质

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