CN101441856B - Backlight module and method for controlling lightness thereof - Google Patents
Backlight module and method for controlling lightness thereof Download PDFInfo
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- CN101441856B CN101441856B CN2008101850332A CN200810185033A CN101441856B CN 101441856 B CN101441856 B CN 101441856B CN 2008101850332 A CN2008101850332 A CN 2008101850332A CN 200810185033 A CN200810185033 A CN 200810185033A CN 101441856 B CN101441856 B CN 101441856B
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Abstract
The invention provides a backlight module and a method for controlling the illumination of the backlight module. The backlight module comprises a plurality of luminous sources, an optical sensor and a control circuit. Each luminous source of the plurality of the luminous sources can be independently operated. The optical sensor is used for detecting the illumination of the plurality of the luminous sources so as to generate a luminance signal. The control circuit is used for driving the plurality of the luminous sources according to the luminance signal. When the backlight module is used for a scanning backlight liquid crystal display, the control circuit closes part of the luminous sources of the plurality of the luminous sources according to a display signal. When the plurality of the luminous sources are all opened, the control circuit reads the luminance signal, and adjusts the illumination of the backlight module according to the luminance signal.
Description
Technical field
The present invention refers to a kind of backlight module of may command brightness of the LCD that is used for scanning backlight especially about the method for a kind of backlight module and control brightness of backlight module.
Background technology
(light emitting diode LED) because volume is little low with power consumption, has been widely used in the backlight liquid crystal display module as light emitting source to light emitting diode.In addition, when the backlight liquid crystal display module is used light emitting diode, normally light-emitting diode (LED) module is arranged in the array that comprises a plurality of row and a plurality of row, but the light emitting source independent operation of each row or each row, so the backlight module of light emitting diode can be used for the LCD of scanning backlight.Yet because the material behavior of light emitting diode, its luminescence efficiency can rise and descend along with temperature.Under the situation of long-time use LCD, the temperature arround the heat that lumination of light emitting diode produced will make rises, and causes brightness of backlight module to descend.Therefore, LCD utilizes an OPTICAL SENSORS to detect brightness of backlight module, and is stable to keep brightness of backlight module.
Please refer to Fig. 1, Fig. 1 is the synoptic diagram of the backlight module of known technology.Backlight module 10 comprises a plurality of light emitting sources 12 and an OPTICAL SENSORS 14.A plurality of light emitting sources 12 are light-emitting diode (LED) module, are arranged in the array that comprises a plurality of row and a plurality of row, but the light emitting source independent operation of each row or each row.OPTICAL SENSORS 14 is arranged near a plurality of light emitting sources 12, is used for detecting the brightness variation of a plurality of light emitting sources 12, and as shown in Figure 1, OPTICAL SENSORS 14 is arranged at the center of backlight module 10.OPTICAL SENSORS 14 produces a luminance signal according to the brightness of a plurality of light emitting sources 12, is used for keeping the brightness stability of a plurality of light emitting sources 12.When backlight module 10 is used for the LCD of scanning backlight, but light emitting source 12 independent operations of each row of backlight module 10 or each row, and backlight module 10 can be according to shows signal closed portion light emitting source 12.Yet when backlight module 10 closed portion light emitting sources 12, the brightness of backlight module 10 descends, if will produce very big error with the brightness that this moment, OPTICAL SENSORS 14 detected luminance signals were adjusted backlight module 10.
Please refer to Fig. 2, Fig. 2 is the synoptic diagram of control signal of the backlight module 10 of Fig. 1.YDIO represents the sweep signal of LCD, and YCLK represents the clock signal of LCD, and on behalf of backlight, ON open, and on behalf of backlight, OFF close.Each row light emitting source 12 of backlight module 10 is all opened in the time at a picture frame, OPTICAL SENSORS 14 detected luminance signals will remain on a voltage quasi position, when luminance signal has change, backlight module 10 can be according to luminance signal adjustment drive the electric current of a plurality of light emitting sources, to keep the brightness stability of backlight module 10.
Please refer to Fig. 3, Fig. 3 is used for the synoptic diagram of control signal of the LCD of scanning backlight for the backlight module 10 of Fig. 1.When backlight module 10 was used for the LCD of scanning backlight, backlight module 10 was along with the light emitting source of the shows signal closed portion of LCD.LCD is closed the backlight 12 of sweep trace opposite position when sweep trace is opened according to shows signal, can reduce the phenomenon of LCD dynamic fuzzy.Therefore, in the time, the light emitting source of each row will be closed a period of time respectively at a picture frame.As shown in Figure 3, when the 1st～135 sweep trace opened, the 1st row backlight was closed, and when the 136th～270 sweep trace opened, the 2nd row backlight was closed ..., when the 946th～1080 sweep trace opened, the 8th row backlight was closed.Yet when the part light emitting source was closed, the voltage quasi position of OPTICAL SENSORS 14 detected luminance signals will reduce, and when pent light emitting source was healed near OPTICAL SENSORS 14, the voltage quasi position of the luminance signal that OPTICAL SENSORS 14 is detected will be lower.Because OPTICAL SENSORS 14 is arranged at the relative position of the 5th row light emitting source, therefore when the 5th row light emitting source was closed, the voltage quasi position of the luminance signal that OPTICAL SENSORS 14 is detected was minimum.
In sum, LCD utilizes OPTICAL SENSORS to detect brightness of backlight module, and is stable to keep brightness of backlight module.Yet, when backlight module is used for the LCD of scanning backlight, because backlight module along with the light emitting source of the shows signal closed portion of LCD, will produce very big error if still adjust brightness of backlight module according to the detected luminance signal of OPTICAL SENSORS this moment.
Summary of the invention
According to embodiments of the invention, provide a kind of method of controlling brightness of backlight module.Described method comprises provides one to have the backlight module and a shows signal of a plurality of light emitting sources, close the part light emitting source of described a plurality of light emitting sources according to described shows signal, when described a plurality of light emitting sources are all opened, the brightness of reading described a plurality of light emitting sources reaches and adjusts described brightness of backlight module according to described luminance signal to produce a luminance signal.
According to embodiments of the invention, other provides a kind of backlight module of may command brightness.Described backlight module comprises a plurality of light emitting sources, an OPTICAL SENSORS and a control circuit.But each light emitting source independent operation of described a plurality of light emitting sources.Described OPTICAL SENSORS is used for detecting the brightness of described a plurality of light emitting sources to produce a luminance signal.Described control circuit is used for cutting out according to a shows signal part light emitting source of described a plurality of light emitting sources, and reads described luminance signal when described a plurality of light emitting sources are all opened.
Embodiments of the invention provide the method for backlight module and control brightness of backlight module, and backlight module comprises a plurality of light emitting sources, an OPTICAL SENSORS and a control circuit.When described a plurality of light emitting sources were all opened, described control circuit read luminance signal, to adjust described brightness of backlight module according to described luminance signal.
Description of drawings
Fig. 1 is the synoptic diagram of the backlight module of known technology.
Fig. 2 is the synoptic diagram of control signal of the backlight module of Fig. 1.
Fig. 3 is used for the synoptic diagram of control signal of the LCD of scanning backlight for the backlight module of Fig. 1.
Fig. 4 is the synoptic diagram of backlight module of the present invention.
Fig. 5 is the synoptic diagram of method first embodiment of control brightness of backlight module of the present invention.
Fig. 6 is the synoptic diagram of method second embodiment of control brightness of backlight module of the present invention.
Drawing reference numeral
10,20 backlight modules 12, more than 22 light emitting source
14,24 OPTICAL SENSORS, 26 control circuits
YDIO sweep signal YCLK clock signal
The ON backlight is opened the OFF backlight and is closed
B hides from view period CH15～CH0 output channel
Embodiment
Please refer to Fig. 4, Fig. 4 is the synoptic diagram of backlight module of the present invention.Backlight module 20 comprises a plurality of light emitting sources 22, an OPTICAL SENSORS 24 and a control circuit 26.A plurality of light emitting sources 22 are light-emitting diode (LED) module, are arranged in the array that comprises a plurality of row and a plurality of row.A plurality of light emitting sources 22 are electrically connected at control circuit 26, but the light emitting source independent operation of each row or each row.Control circuit 26 cuts out the part light emitting source of a plurality of light emitting sources 22 according to a shows signal.OPTICAL SENSORS 24 is arranged near a plurality of light emitting sources 22, be used for detecting the brightness variation of a plurality of light emitting sources 22, the position of OPTICAL SENSORS 24 is restriction not, normal light sensor 24 can be arranged at the position of the mean flow rate that can detect backlight module 20, as shown in Figure 4, OPTICAL SENSORS 24 is arranged at the center of backlight module 20.OPTICAL SENSORS 24 is electrically connected at control circuit 26, and produces a luminance signal according to the brightness of a plurality of light emitting sources 22 and be sent to control circuit 26.In an embodiment of the present invention, backlight module 20 is used for the LCD of scanning backlight, when control circuit 26 during according to shows signal closed portion light emitting source 22, control circuit 26 does not read OPTICAL SENSORS 24 detected luminance signals, when a plurality of light emitting sources 22 were all opened, control circuit 26 just went to read OPTICAL SENSORS 24 detected luminance signals.
Please refer to Fig. 5, Fig. 5 is the synoptic diagram of method first embodiment of control brightness of backlight module of the present invention.In the present embodiment, explain with the backlight module 20 of Fig. 4, control circuit 26 can cut out the light emitting source 22 of each row according to shows signal.The brightness that backlight module 20 uses OPTICAL SENSORS 24 to detect a plurality of light emitting sources 22 changes, and forms feedback loop to keep the brightness stability of a plurality of light emitting sources 22 by control circuit 26.Yet, when backlight module 20 is used for the LCD of scanning backlight, backlight module 20 is along with the light emitting source of the shows signal closed portion of LCD, and control circuit 26 then can produce error as if the brightness of adjusting light emitting source 22 according to OPTICAL SENSORS 24 detected luminance signals at this moment.When backlight module 20 was used for the LCD of scanning backlight, the signal of controlling a plurality of light emitting sources 22 as shown in Figure 5.YDIO represents the sweep signal of LCD, and YCLK represents the clock signal of LCD, and on behalf of backlight, ON open, and on behalf of backlight, OFF close.LCD is closed the backlight 22 of sweep trace opposite position when sweep trace is opened according to shows signal, can reduce the phenomenon of LCD dynamic fuzzy.Therefore, in the time, the light emitting source of each row will be closed a period of time respectively at a picture frame.When the 1st～135 sweep trace opened, the 1st row backlight was closed, and when the 136th～270 sweep trace opened, the 2nd row backlight was closed ..., when the 946th～1080 sweep trace opened, the 8th row backlight was closed.LCD has one section and hides from view (blanking) period B between each picture frame, this moment, all light emitting sources 22 of backlight module 20 were all opened, therefore control circuit 26 of the present invention just reads the luminance signal that OPTICAL SENSORS 24 is detected at the period B that hides from view of LCD, control circuit 26 is according to the brightness of hiding from view the adjustment light emitting source 22 that luminance signal that period B reads can be correct, to keep the brightness stability of light emitting source 22.
Please refer to Fig. 6, Fig. 6 is the synoptic diagram of method second embodiment of control brightness of backlight module of the present invention.In the present embodiment, equally the backlight module 20 with Fig. 4 explains, and different is, control circuit 26 can be according to the light emitting source 22 of each row of shows signal independent operation and each row, and for example, the light emitting source of each row comprises the output channel CH15～CH0 of 16 row.When backlight module 20 was used for the LCD of scanning backlight, control circuit 26 utilized the work period (duty cycle) to control the light emitting source 22 of each row and each row.Light emitting source 22 with the 1st row is an example, and the work period of output channel CH15 is 50%, represent the 1st light emitting source 22 that is listed as the 1st row in front half picture frame time open, half picture frame time of back closes.The work period of output channel CH14 is 60%, represents the 1st light emitting source 22 that is listed as the 2nd row to open in preceding 60% picture frame time, and the picture frame time of back 40% closes.Therefore, when control circuit 26 utilized the work period to control the light emitting source 22 of each row and each row, control circuit 26 must just read the luminance signal that OPTICAL SENSORS 24 is detected when a plurality of light emitting sources 22 are all opened.As shown in Figure 6, the work period of output channel CH15, CH14, CH13, CH12 is respectively 50%, 60%, 80%, 40%, output channel CH11～CH0 then is all 100%, so control circuit 26 will be according to the work period 40% of minimum, the picture frame preceding 40% reads the luminance signal that OPTICAL SENSORS 24 is detected in the time.It should be noted that it is work period according to the minimum of a plurality of light emitting sources 22 that control circuit 26 reads luminance signal that OPTICAL SENSORS 24 detected.For example, the work period of the minimum of the light emitting source of the 1st row is that the work period of the minimum of 40%, the 2 light emitting source that is listed as is 30%, and then control circuit 26 needs the picture frame preceding 30% read the luminance signal that OPTICAL SENSORS 24 is detected in the time.
According to the first embodiment of the present invention and second embodiment, the OPTICAL SENSORS 24 of utilizing backlight module 20 detects the brightness of a plurality of light emitting sources 22 to produce luminance signal, when a plurality of light emitting sources 22 were all opened, control circuit 26 just went to read OPTICAL SENSORS 24 detected luminance signals.In first embodiment, control circuit 26 can cut out the light emitting source 22 of each row according to shows signal, so control circuit 26 reads the luminance signal that OPTICAL SENSORS 24 is detected in the period of hiding from view of LCD.In a second embodiment, control circuit 26 can cut out the light emitting source 22 of each row and each row according to shows signal, so control circuit 26 reads the luminance signal that OPTICAL SENSORS 24 is detected in the work period of the minimum of a plurality of light emitting sources 22.In a word, for a plurality of light emitting sources that can independently control, control circuit only just goes to read the detected luminance signal of OPTICAL SENSORS when a plurality of light emitting sources are all opened.
In sum, the invention provides the method for a kind of backlight module and control brightness of backlight module.Backlight module comprises a plurality of light emitting sources, an OPTICAL SENSORS and a control circuit.But each light emitting source independent operation of described a plurality of light emitting sources.Described OPTICAL SENSORS is used for detecting the brightness of described a plurality of light emitting sources to produce a luminance signal.Described control circuit drives described a plurality of light emitting source according to described luminance signal.When described backlight module was used for one scan formula LCD backlight, described control circuit cut out the part light emitting source of described a plurality of light emitting sources according to a shows signal.When described a plurality of light emitting sources were all opened, described control circuit read described luminance signal, to adjust described brightness of backlight module according to described luminance signal.
The above only is preferred embodiment of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to covering scope of the present invention.
Claims (12)
1. a method of controlling brightness of backlight module is characterized in that, described method comprises:
One backlight module with a plurality of light emitting sources is provided;
One shows signal is provided;
Close the part light emitting source of described a plurality of light emitting sources according to described shows signal;
When described a plurality of light emitting sources are all opened, read from light sensors to the brightness of described a plurality of light emitting sources to produce a luminance signal; And
Adjust described brightness of backlight module according to described luminance signal.
2. the method for claim 1 is characterized in that, provides a backlight module with a plurality of light emitting sources to comprise to provide a backlight module with a plurality of light emitting sources of lining up a plurality of row.
3. method as claimed in claim 2 is characterized in that, the part light emitting source of closing described a plurality of light emitting sources according to described shows signal comprises according to described shows signal closes the wherein light emitting source of row of described a plurality of row.
4. the method for claim 1, it is characterized in that the part light emitting source of closing described a plurality of light emitting sources according to described shows signal comprises according to described shows signal adjusts the work period of described a plurality of light emitting sources to close the part light emitting source of described a plurality of light emitting sources.
5. the method for claim 1, it is characterized in that, when described a plurality of light emitting sources are all opened, the brightness of reading described a plurality of light emitting sources comprises that to produce described luminance signal the brightness of reading described a plurality of light emitting sources is to produce described luminance signal when the work period of described a plurality of light emitting sources all is unlatching.
6. the method for claim 1, it is characterized in that, when described a plurality of light emitting sources are all opened, the brightness of reading described a plurality of light emitting sources is included in one and hides from view the period and make described a plurality of light emitting source all open to produce described luminance signal, and the brightness of reading described a plurality of light emitting sources is to produce described luminance signal.
7. the backlight module of a may command brightness is characterized in that, described backlight module comprises:
A plurality of light emitting sources, but each light emitting source independent operation;
One OPTICAL SENSORS is used for detecting the brightness of described a plurality of light emitting sources to produce a luminance signal; And
One control circuit is used for cutting out according to a shows signal part light emitting source of described a plurality of light emitting sources, and reads described luminance signal when described a plurality of light emitting sources are all opened.
8. backlight module as claimed in claim 7 is characterized in that, described a plurality of light emitting sources are lined up a plurality of row.
9. backlight module as claimed in claim 8 is characterized in that, the same row light emitting source of a plurality of light emitting sources can be closed simultaneously.
10. backlight module as claimed in claim 7 is characterized in that, described control circuit utilization is adjusted the work period of described a plurality of light emitting sources to close described a plurality of light emitting source.
11. backlight module as claimed in claim 7 is characterized in that, described control circuit reads described luminance signal when the work period of described a plurality of light emitting sources all is unlatching.
12. backlight module as claimed in claim 7 is characterized in that, described control circuit in hiding from view the period when making that described a plurality of light emitting source is all opened, reads described luminance signal in described shows signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101850332A CN101441856B (en) | 2008-12-26 | 2008-12-26 | Backlight module and method for controlling lightness thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2008101850332A CN101441856B (en) | 2008-12-26 | 2008-12-26 | Backlight module and method for controlling lightness thereof |
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| CN101441856A CN101441856A (en) | 2009-05-27 |
| CN101441856B true CN101441856B (en) | 2010-09-29 |
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| CN102194422A (en) * | 2011-06-10 | 2011-09-21 | 中航华东光电有限公司 | Control circuit of backlight module and control method thereof |
| CN107731174B (en) * | 2017-10-31 | 2019-12-24 | 武汉天马微电子有限公司 | Display device and electronic equipment |
| CN111199697B (en) * | 2018-11-16 | 2023-06-30 | 瑞昱半导体股份有限公司 | Display device and display method for reducing dynamic blurring |
| CN109448642B (en) * | 2018-12-13 | 2020-12-18 | 厦门天马微电子有限公司 | Display module, driving method thereof and display device |
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