CN103093727B - Backlight control signal method of adjustment and device - Google Patents
Backlight control signal method of adjustment and device Download PDFInfo
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- CN103093727B CN103093727B CN201310024325.9A CN201310024325A CN103093727B CN 103093727 B CN103093727 B CN 103093727B CN 201310024325 A CN201310024325 A CN 201310024325A CN 103093727 B CN103093727 B CN 103093727B
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Abstract
The invention discloses a kind of backlight control signal method of adjustment and device, its method comprises: obtain the frequency of sweep signal and the screen parameter of LCDs; According to the frequency of described sweep signal, determine the frequency of present PWM signal; According to the screen parameter of described LCDs, determine the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal; When the trigger instants of the rising edge of present PWM signal arrives, trigger the rising edge of the pwm signal in the pwm signal cycle, and according to the frequency of present PWM signal, high level part and low level part, export described pwm signal.The present invention avoids not mating to cause because of pwm signal and the frequency of sweep signal to there is phase shifts or pwm signal between the two on the liquid-crystalline glasses of LCDs because reversal of poles causes the cramping at liquid crystal two ends to change, and effectively prevent phenomenon LCDs occurring rolling water wave ripple.<!--1-->
Description
Technical field
The present invention relates to liquid crystal technology field, be related specifically to backlight control signal method of adjustment and device.
Background technology
At present, liquid crystal TV set becomes main flow on the market, and just at fast growth.The LCDs great majority of liquid crystal TV set adopt LED or cold cathode fluorescent lamp as backlight, the pwm signal that liquid crystal TV set provides a fixed frequency by counter control register is used for controlling the switch of liquid crystal screen back light source, and is adjusted the brightness of backlight by the dutycycle adjusting this PWM.The system board of liquid crystal TV set provides sweep signal Vsync to LCDs, and to carry out the scanning of screen-picture, this sweep signal frequency is not a fixed value, relevant with the Vsync signal of input.When the pwm signal frequency f being used for controlling LCD screen backlight that counter control register provides
pWMthe sweep signal frequency f provided with system board
vSYNCwhen not mating, there is phase shifts between the two, cause in LCDs and occur rolling water ripple phenomenon.Even if there is not phase association and frequency association between pwm pulse and Vsync, but due to the code book on the liquid-crystalline glasses of LCDs in reversal of poles time, there is slight change in the cramping at liquid crystal two ends, the rolling water ripple phenomenon of overall picture can be caused equally to occur.The appearance of these rolling water ripples, seriously have impact on the visual effect of beholder, and causes bad impact to the eyesight of beholder.
Summary of the invention
Fundamental purpose of the present invention for provide a kind of effectively avoid rolling water ripples to disturb backlight control signal method of adjustment and device.
The present invention proposes a kind of backlight control signal method of adjustment, comprises step:
Obtain the frequency of sweep signal and the screen parameter of LCDs;
According to the frequency of described sweep signal, determine the frequency of present PWM signal;
According to the screen parameter of described LCDs, determine the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal;
When the trigger instants of the rising edge of present PWM signal arrives, trigger the rising edge of the pwm signal in the pwm signal cycle, and according to the frequency of present PWM signal, high level part and low level part, export described pwm signal.
Preferably, the described screen parameter according to LCDs, determine that the step of the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal specifically comprises:
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal;
According to the Clock Multiplier Factor PreScale preset and described scanning number of buses Vtotal, obtain the number of scanning lines M=Vtotal ÷ PreScale of described sweep signal within a pwm signal cycle;
According to the occupy ratio duty preset and the number of scanning lines M of described sweep signal within a pwm signal cycle, obtain high level number of scanning lines N1=M × duty and low level number of scanning lines N2=M × (1-duty), the high level part of the corresponding present PWM signal of described high level number of scanning lines N1 within a pwm signal cycle, the low level part of the corresponding present PWM signal of described low level number of scanning lines N2 within a pwm signal cycle;
Described sweep signal is arrived the moment of (i-1) × M+1 horizontal scanning line, be defined as the trigger instants of the rising edge of the pwm signal in i-th pwm signal cycle of triggering.
Preferably, the described frequency according to sweep signal, determine that the step of the frequency of present PWM signal specifically comprises:
According to the Clock Multiplier Factor PreScale preset and the frequency f of described sweep signal
vSYNC, obtain the frequency f of pwm signal
pWM=PreScale × f
vSYNC.
Preferably, the described screen parameter according to LCDs, also comprises after determining the step of the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal:
In Preset Time, the frequency detecting described sweep signal whether within the scope of the sweep signal frequency threshold preset, whether the frequency of present PWM signal within the scope of the pwm signal frequency threshold preset;
When the frequency of described sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of present PWM signal is when exceeding default pwm signal frequency threshold scope, using the trigger instants of the trigger instants of the rising edge of a front pwm signal as the rising edge of present PWM signal, using the frequency of the frequency of a front pwm signal as present PWM signal, using the high level part of the high level part of a front pwm signal as present PWM signal, using the low level part of the low level part of a front pwm signal as present PWM signal.
The present invention also proposes a kind of backlight control signal adjusting gear, comprising:
Acquisition module, for the screen parameter of the frequency and LCDs that obtain sweep signal;
Generation module, for the frequency according to described sweep signal, determines the frequency of present PWM signal; According to the screen parameter of described LCDs, determine the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal;
Trigger module, when the trigger instants for the rising edge at present PWM signal arrives, triggers the rising edge of the pwm signal in the pwm signal cycle, and according to the frequency of present PWM signal, high level part and low level part, exports described pwm signal.
Preferably, described generation module specifically for:
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal;
According to the Clock Multiplier Factor PreScale preset and described scanning number of buses Vtotal, obtain the number of scanning lines M=Vtotal ÷ PreScale of described sweep signal within a pwm signal cycle;
According to the occupy ratio duty preset and the number of scanning lines M of described sweep signal within a pwm signal cycle, obtain high level number of scanning lines N1=M × duty and low level number of scanning lines N2=M × (1-duty), the high level part of the corresponding present PWM signal of described high level number of scanning lines N1 within a pwm signal cycle, the low level part of the corresponding present PWM signal of described low level number of scanning lines N2 within a pwm signal cycle;
Described sweep signal is arrived the moment of (i-1) × M+1 horizontal scanning line, be defined as the trigger instants of the rising edge of the pwm signal in i-th pwm signal cycle of triggering.
Preferably, described generation module also specifically for:
According to the Clock Multiplier Factor PreScale preset and the frequency f of described sweep signal
vSYNC, obtain the frequency f of pwm signal
pWM=PreScale × f
vSYNC.
Preferably, described backlight control signal adjusting gear, also comprises protection module, for:
In Preset Time, the frequency detecting described sweep signal whether within the scope of the sweep signal frequency threshold preset, whether the frequency of present PWM signal within the scope of the pwm signal frequency threshold preset;
When the frequency of described sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of present PWM signal is when exceeding default pwm signal frequency threshold scope, using the trigger instants of the trigger instants of the rising edge of a front pwm signal as the rising edge of present PWM signal, using the frequency of the frequency of a front pwm signal as present PWM signal, using the high level part of the high level part of a front pwm signal as present PWM signal, using the low level part of the low level part of a front pwm signal as present PWM signal.
The present invention adjusts the output of pwm signal according to the screen parameter of the frequency of sweep signal and LCDs, avoid not mating to cause because of pwm signal and the frequency of sweep signal to there is phase shifts or pwm signal between the two on the liquid-crystalline glasses of LCDs because reversal of poles causes the cramping at liquid crystal two ends to change, effectively prevent phenomenon LCDs occurring rolling water wave ripple.
Accompanying drawing explanation
Fig. 1 is the process flow diagram of the first embodiment of backlight control signal method of adjustment of the present invention;
Fig. 2 is the process flow diagram of the second embodiment of backlight control signal method of adjustment of the present invention;
Fig. 3 is the process flow diagram of the 3rd embodiment of backlight control signal method of adjustment of the present invention;
Fig. 4 is the process flow diagram of the 4th embodiment of backlight control signal method of adjustment of the present invention;
Fig. 5 is the structural representation of the first embodiment of backlight control signal adjusting gear of the present invention;
Fig. 6 is the structural representation of the second embodiment of backlight control signal adjusting gear of the present invention.
The realization of the object of the invention, functional characteristics and advantage will in conjunction with the embodiments, are described further with reference to accompanying drawing.
Embodiment
Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
As shown in Figure 1, Fig. 1 is the process flow diagram of the first embodiment of backlight control signal method of adjustment of the present invention.The backlight control signal method of adjustment that the present embodiment is mentioned comprises:
Step S10, obtains the frequency of sweep signal and the screen parameter of LCDs;
The method of the present embodiment is implemented to perform by the system board of liquid crystal display.Wherein, system board is connected with LCDs, and sweep signal is produced by system board, and screen parameter can directly be stored in the storer of system board, also can be obtained to LCDs by system board.
Step S20, according to the frequency of sweep signal, determines the frequency of present PWM signal;
In order to avoid not mating with the frequency of sweep signal because of pwm signal, cause and there is phase shifts between the two, therefore, the present embodiment determines the frequency of present PWM signal according to the frequency of sweep signal, is conducive to the phenomenon avoiding LCDs occurring rolling water wave ripple.
Step S30, according to the screen parameter of LCDs, determines the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal;
In order to avoid pwm signal on the liquid-crystalline glasses of LCDs because of reversal of poles, the cramping at liquid crystal two ends is caused to change, therefore, the present embodiment determines the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal according to the screen parameter of LCDs, avoids the situation of rolling water wave ripple to occur further.
Step S40, when the trigger instants of the rising edge of present PWM signal arrives, triggers the rising edge of the pwm signal in the pwm signal cycle, and according to the frequency of present PWM signal, high level part and low level part, output pwm signal.
The pwm signal of the present embodiment is produced by the system board of liquid crystal display, and exports the backlight constant current plate of LCDs to, controls the brightness of backlight.Avoid the problem of the TV flicker that the existing pwm signal produced by counter control register is caused because the backlight dutycycle occurred in television system handoff procedure changes suddenly.Simultaneously, the present embodiment adjusts the output of pwm signal according to the screen parameter of the frequency of sweep signal and LCDs, avoid not mating to cause because of pwm signal and the frequency of sweep signal to there is phase shifts or pwm signal between the two on the liquid-crystalline glasses of LCDs because reversal of poles causes the cramping at liquid crystal two ends to change, effectively prevent phenomenon LCDs occurring rolling water wave ripple.
As shown in Figure 2, Fig. 2 is the process flow diagram of the second embodiment of backlight control signal method of adjustment of the present invention.The present embodiment is on basis embodiment illustrated in fig. 1, and describe in detail step S20, step S20 specifically comprises:
Step S21, according to the Clock Multiplier Factor PreScale preset and the frequency f of sweep signal
vSYNC, obtain the frequency f of pwm signal
pWM=PreScale × f
vSYNC.
The Clock Multiplier Factor PreScale preset of the present embodiment is natural number, such as f
vSYNC=60Hz, PreScale=2, f
pWM=2 × 60=120Hz.The present embodiment determines the frequency of present PWM signal according to the frequency of sweep signal, can guarantee to keep stable frequency relation between pwm signal and sweep signal, avoid because pwm signal does not mate with the frequency of sweep signal, cause and there is phase shifts between the two, be conducive to the phenomenon avoiding LCDs occurring rolling water wave ripple.
As shown in Figure 3, Fig. 3 is the process flow diagram of the 3rd embodiment of backlight control signal method of adjustment of the present invention.The present embodiment is on basis embodiment illustrated in fig. 1, and describe in detail step S30, step S30 specifically comprises:
Step S31, according to the screen parameter of LCDs, obtains scanning number of buses Vtotal;
The system board of the present embodiment is according to the vertical busses number Vtotal of the known image scanning of screen parameter of LCDs, and such as, Vtotal is 1125 row.
Step S32, according to the Clock Multiplier Factor PreScale preset and scanning number of buses Vtotal, obtains the number of scanning lines M=Vtotal ÷ PreScale of sweep signal within a pwm signal cycle;
According to the Clock Multiplier Factor PreScale that system board is preset, calculate scanning M line by the cycle of a generation PWM waveform.Wherein, the result of calculation that the Clock Multiplier Factor PreScale preset generally is more than or equal to 2, M gets the integer rounded up.Such as, PreScale=2, Vtotal=1125 are capable, and M=1125 ÷ 2=563 is capable, and namely every 563 line scan signals are a PWM cycle.
Step S33, according to the occupy ratio duty preset and the number of scanning lines M of sweep signal within a pwm signal cycle, obtain high level number of scanning lines N1=M × duty and low level number of scanning lines N2=M × (1-duty), the high level part of the corresponding present PWM signal of high level number of scanning lines N1 within a pwm signal cycle, the low level part of the corresponding present PWM signal of low level number of scanning lines N2 within a pwm signal cycle;
The result of calculation of high level number of scanning lines N1 and low level number of scanning lines N2 gets the integer rounded up.Such as, duty=30%, N1=563 × 30%=169 is capable, N2=563 × (1-30%)=394 row, namely within the sweep time of 563 row, has are high level 169 horizontal-scanning intervals, and the sweep time of other 394 row is low level.Determine high level part and the low level part of present PWM signal according to the screen parameter of LCDs, pwm signal can be avoided on the liquid-crystalline glasses of LCDs because of reversal of poles, cause the cramping at liquid crystal two ends to change.
Step S34, arrives by sweep signal in the moment of (i-1) × M+1 horizontal scanning line, is defined as the trigger instants of the rising edge of the pwm signal in i-th pwm signal cycle of triggering.
By the rising edge of pwm signal in the pwm signal cycle and the rising edge alignment of sweep signal, guarantee between pwm signal and sweep signal, to keep stable phase relation, avoid the situation of rolling water wave ripple to occur further.
As shown in Figure 4, Fig. 4 is the process flow diagram of the 4th embodiment of backlight control signal method of adjustment of the present invention.The present embodiment, on basis embodiment illustrated in fig. 1, adds the step of frequency protection, namely also comprises after step S30:
Step S51, in Preset Time, detects the frequency f of sweep signal
vSYNCwhether f within the scope of the sweep signal frequency threshold preset
mIN-VSYNC≤ f
vSYNC≤ f
mAX-VSYNC, present PWM signal frequency f
pWMwhether f within the scope of the pwm signal frequency threshold preset
mIN-PWM≤ f
pWM≤ f
mAX-PWM; If so, then step S40 is performed; If not, then step S52 is performed;
Step S52, in the frequency f of sweep signal
vSYNCexceed default sweep signal frequency threshold scope f
vSYNC< f
mIN-VSYNCor f
vSYNC> f
mAX-VSYNCtime, or the frequency f of present PWM signal
pWMexceed default pwm signal frequency threshold scope f
pWM< f
mIN-PWMor f
vSYNC> f
mAX-PWMtime, using the trigger instants of the trigger instants of the rising edge of a front pwm signal as the rising edge of present PWM signal, using the frequency of the frequency of a front pwm signal as present PWM signal, using the high level part of the high level part of a front pwm signal as present PWM signal, using the low level part of the low level part of a front pwm signal as present PWM signal.
The present embodiment considers following situation, when sweep signal is unstable, sweep signal frequency can be caused to produce transient change, if now pwm signal frequency along with the sweep signal frequency of instability adjust time, then easily produce rolling water wave wave interference, in order to avoid above-mentioned situation occurs, when sweep signal is unstable, keep pwm signal according to the frequency of the pwm signal of last subnormal output and phase place, by the time after sweep signal frequency stabilization, again according to frequency and the phase place of stable sweep signal adjustment pwm signal, the situation that further avoid rolling water wave ripple occurs.
As shown in Figure 5, Fig. 5 is the structural representation of the first embodiment of backlight control signal adjusting gear of the present invention.The backlight control signal adjusting gear that the present embodiment is mentioned comprises:
Acquisition module 10, for the screen parameter of the frequency and LCDs that obtain sweep signal;
Generation module 20, for the frequency according to sweep signal, determines the frequency of present PWM signal; According to the screen parameter of LCDs, determine the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal;
Trigger module 30, when the trigger instants for the rising edge at present PWM signal arrives, triggers the rising edge of the pwm signal in the pwm signal cycle, and according to the frequency of present PWM signal, high level part and low level part, output pwm signal.
This device is arranged in the system board of liquid crystal display.Wherein, system board is connected with LCDs, and sweep signal is produced by system board, and screen parameter can directly be stored in the storer of system board, also can be obtained to LCDs by system board.In order to avoid not mating with the frequency of sweep signal because of pwm signal, cause and there is phase shifts between the two, therefore, the present embodiment determines the frequency of present PWM signal according to the frequency of sweep signal, is conducive to the phenomenon avoiding LCDs occurring rolling water wave ripple.In order to avoid pwm signal on the liquid-crystalline glasses of LCDs because of reversal of poles, the cramping at liquid crystal two ends is caused to change, therefore, the present embodiment determines the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal according to the screen parameter of LCDs, avoids the situation of rolling water wave ripple to occur further.The pwm signal of the present embodiment is produced by the system board of liquid crystal display, and exports the backlight constant current plate of LCDs to, controls the brightness of backlight.Avoid the problem of the TV flicker that the existing pwm signal produced by counter control register is caused because the backlight dutycycle occurred in television system handoff procedure changes suddenly.Simultaneously, the present embodiment adjusts the output of pwm signal according to the screen parameter of the frequency of sweep signal and LCDs, avoid not mating to cause because of pwm signal and the frequency of sweep signal to there is phase shifts or pwm signal between the two on the liquid-crystalline glasses of LCDs because reversal of poles causes the cramping at liquid crystal two ends to change, effectively prevent phenomenon LCDs occurring rolling water wave ripple.
The generation module 20 of the embodiment of the present invention specifically for:
According to the Clock Multiplier Factor PreScale preset and the frequency f of sweep signal
vSYNC, obtain the frequency f of pwm signal
pWM=PreScale × f
vSYNC.
The Clock Multiplier Factor PreScale preset of the present embodiment is natural number, such as f
vSYNC=60Hz, PreScale=2, f
pWM=2 × 60=120Hz.The present embodiment determines the frequency of present PWM signal according to the frequency of sweep signal, can guarantee to keep stable frequency relation between pwm signal and sweep signal, avoid because pwm signal does not mate with the frequency of sweep signal, cause and there is phase shifts between the two, be conducive to the phenomenon avoiding LCDs occurring rolling water wave ripple.
The generation module 20 of the embodiment of the present invention also specifically for:
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal;
According to the Clock Multiplier Factor PreScale preset and scanning number of buses Vtotal, obtain the number of scanning lines M=Vtotal ÷ PreScale of sweep signal within a pwm signal cycle;
According to the occupy ratio duty preset and the number of scanning lines M of sweep signal within a pwm signal cycle, obtain high level number of scanning lines N1=M × duty and low level number of scanning lines N2=M × (1-duty), the high level part of the corresponding present PWM signal of high level number of scanning lines N1 within a pwm signal cycle, the low level part of the corresponding present PWM signal of low level number of scanning lines N2 within a pwm signal cycle;
Sweep signal is arrived the moment of (i-1) × M+1 horizontal scanning line, be defined as the trigger instants of the rising edge of the pwm signal in i-th pwm signal cycle of triggering.
The system board of the present embodiment is according to the vertical busses number Vtotal of the known image scanning of screen parameter of LCDs, and such as, Vtotal is 1125 row.According to the Clock Multiplier Factor PreScale that system board is preset, calculate scanning M line by the cycle of a generation PWM waveform.Wherein, the result of calculation that the Clock Multiplier Factor PreScale preset generally is more than or equal to 2, M gets the integer rounded up.Such as, PreScale=2, Vtotal=1125 are capable, and M=1125 ÷ 2=563 is capable, and namely every 563 line scan signals are a PWM cycle.The result of calculation of high level number of scanning lines N1 and low level number of scanning lines N2 gets the integer rounded up.Such as, duty=30%, N1=563 × 30%=169 is capable, N2=563 × (1-30%)=394 row, namely within the sweep time of 563 row, has are high level 169 horizontal-scanning intervals, and the sweep time of other 394 row is low level.Determine high level part and the low level part of present PWM signal according to the screen parameter of LCDs, pwm signal can be avoided on the liquid-crystalline glasses of LCDs because of reversal of poles, cause the cramping at liquid crystal two ends to change.By the rising edge of pwm signal in the pwm signal cycle and the rising edge alignment of sweep signal, guarantee between pwm signal and sweep signal, to keep stable phase relation, avoid the situation of rolling water wave ripple to occur further.
As shown in Figure 6, Fig. 6 is the structural representation of the second embodiment of backlight control signal adjusting gear of the present invention.The present embodiment adds protection module 40 on basis embodiment illustrated in fig. 5, for:
In Preset Time, the frequency detecting sweep signal whether within the scope of the sweep signal frequency threshold preset, whether the frequency of present PWM signal within the scope of the pwm signal frequency threshold preset;
When the frequency of sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of present PWM signal is when exceeding default pwm signal frequency threshold scope, using the trigger instants of the trigger instants of the rising edge of a front pwm signal as the rising edge of present PWM signal, using the frequency of the frequency of a front pwm signal as present PWM signal, using the high level part of the high level part of a front pwm signal as present PWM signal, using the low level part of the low level part of a front pwm signal as present PWM signal.
The present embodiment considers following situation, when sweep signal is unstable, sweep signal frequency can be caused to produce transient change, if now pwm signal frequency along with the sweep signal frequency of instability adjust time, then easily produce rolling water wave wave interference, in order to avoid above-mentioned situation occurs, when sweep signal is unstable, keep pwm signal according to the frequency of the pwm signal of last subnormal output and phase place, by the time after sweep signal frequency stabilization, again according to frequency and the phase place of stable sweep signal adjustment pwm signal, the situation that further avoid rolling water wave ripple occurs.
The foregoing is only the preferred embodiments of the present invention; not thereby the scope of the claims of the present invention is limited; every utilize instructions of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.
Claims (8)
1. a backlight control signal method of adjustment, is characterized in that, comprises step:
Obtain the frequency of sweep signal and the screen parameter of LCDs;
According to the frequency of described sweep signal, determine the frequency of present PWM signal;
According to the screen parameter of LCDs, obtain scanning number of buses Vtotal; According to the Clock Multiplier Factor PreScale preset and described scanning number of buses Vtotal, obtain the number of scanning lines M=Vtotal ÷ PreScale of described sweep signal within a pwm signal cycle; The trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal is determined according to the occupy ratio duty preset and the number of scanning lines M of described sweep signal within a pwm signal cycle;
If in Preset Time, the frequency detecting described sweep signal within the scope of the sweep signal frequency threshold preset, the frequency of present PWM signal is within the scope of the pwm signal frequency threshold preset; Then when the trigger instants of the rising edge of present PWM signal arrives, trigger the rising edge of the pwm signal in the pwm signal cycle, and according to the frequency of present PWM signal, high level part and low level part, export described pwm signal.
2. backlight control signal method of adjustment according to claim 1, it is characterized in that, the described screen parameter according to LCDs, determine that the step of the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal specifically comprises:
According to the occupy ratio duty preset and the number of scanning lines M of described sweep signal within a pwm signal cycle, obtain high level number of scanning lines N1=M × duty and low level number of scanning lines N2=M × (1-duty), the high level part of the corresponding present PWM signal of described high level number of scanning lines N1 within a pwm signal cycle, the low level part of the corresponding present PWM signal of described low level number of scanning lines N2 within a pwm signal cycle;
Described sweep signal is arrived the moment of (i-1) × M+1 horizontal scanning line, be defined as the trigger instants of the rising edge of the pwm signal in i-th pwm signal cycle of triggering.
3. backlight control signal method of adjustment according to claim 2, is characterized in that, the described frequency according to sweep signal, determines that the step of the frequency of present PWM signal specifically comprises:
According to the Clock Multiplier Factor PreScale preset and the frequency f of described sweep signal
vSYNC, obtain the frequency f of pwm signal
pWM=PreScale × f
vSYNC.
4. the backlight control signal method of adjustment according to Claims 2 or 3, it is characterized in that, the described screen parameter according to LCDs, also comprises after determining the step of the trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal:
In Preset Time, the frequency detecting described sweep signal whether within the scope of the sweep signal frequency threshold preset, whether the frequency of present PWM signal within the scope of the pwm signal frequency threshold preset;
When the frequency of described sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of present PWM signal is when exceeding default pwm signal frequency threshold scope, using the trigger instants of the trigger instants of the rising edge of a front pwm signal as the rising edge of present PWM signal, using the frequency of the frequency of a front pwm signal as present PWM signal, using the high level part of the high level part of a front pwm signal as present PWM signal, using the low level part of the low level part of a front pwm signal as present PWM signal.
5. a backlight control signal adjusting gear, is characterized in that, comprising:
Acquisition module, for the screen parameter of the frequency and LCDs that obtain sweep signal;
Generation module, for the frequency according to described sweep signal, determines the frequency of present PWM signal; According to the screen parameter of LCDs, obtain scanning number of buses Vtotal; According to the Clock Multiplier Factor PreScale preset and described scanning number of buses Vtotal, obtain the number of scanning lines M=Vtotal ÷ PreScale of described sweep signal within a pwm signal cycle; The trigger instants of the high level part of present PWM signal and the rising edge of low level part and present PWM signal is determined according to the occupy ratio duty preset and the number of scanning lines M of described sweep signal within a pwm signal cycle;
Trigger module, when the trigger instants for the rising edge at present PWM signal arrives, triggers the rising edge of the pwm signal in the pwm signal cycle, and according to the frequency of present PWM signal, high level part and low level part, exports described pwm signal.
6. backlight control signal adjusting gear according to claim 5, is characterized in that, described generation module specifically for:
According to the occupy ratio duty preset and the number of scanning lines M of described sweep signal within a pwm signal cycle, obtain high level number of scanning lines N1=M × duty and low level number of scanning lines N2=M × (1-duty), the high level part of the corresponding present PWM signal of described high level number of scanning lines N1 within a pwm signal cycle, the low level part of the corresponding present PWM signal of described low level number of scanning lines N2 within a pwm signal cycle;
Described sweep signal is arrived the moment of (i-1) × M+1 horizontal scanning line, be defined as the trigger instants of the rising edge of the pwm signal in i-th pwm signal cycle of triggering.
7. backlight control signal adjusting gear according to claim 6, is characterized in that, described generation module also specifically for:
According to the Clock Multiplier Factor PreScale preset and the frequency f of described sweep signal
vSYNC, obtain the frequency f of pwm signal
pWM=PreScale × f
vSYNC.
8. the backlight control signal adjusting gear according to claim 6 or 7, is characterized in that, also comprise protection module, for:
In Preset Time, the frequency detecting described sweep signal whether within the scope of the sweep signal frequency threshold preset, whether the frequency of present PWM signal within the scope of the pwm signal frequency threshold preset;
When the frequency of described sweep signal exceeds default sweep signal frequency threshold scope, or the frequency of present PWM signal is when exceeding default pwm signal frequency threshold scope, using the trigger instants of the trigger instants of the rising edge of a front pwm signal as the rising edge of present PWM signal, using the frequency of the frequency of a front pwm signal as present PWM signal, using the high level part of the high level part of a front pwm signal as present PWM signal, using the low level part of the low level part of a front pwm signal as present PWM signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310024325.9A CN103093727B (en) | 2013-01-23 | 2013-01-23 | Backlight control signal method of adjustment and device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310024325.9A CN103093727B (en) | 2013-01-23 | 2013-01-23 | Backlight control signal method of adjustment and device |
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| Publication Number | Publication Date |
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| CN104299578B (en) * | 2014-11-10 | 2016-09-14 | 深圳市华星光电技术有限公司 | Back light unit and driving method, liquid crystal indicator |
| CN104851374A (en) * | 2015-06-04 | 2015-08-19 | 深圳康荣电子有限公司 | Air circulation refrigerating advertising player and refrigerating method thereof |
| CN107195275B (en) | 2017-07-27 | 2019-09-06 | 青岛海信电器股份有限公司 | A kind of multi partition dynamic backlight driving method and TV |
| CN113035136B (en) * | 2019-12-09 | 2022-06-21 | 瑞昱半导体股份有限公司 | Signal processing method for maintaining relative relationship of signals and electronic device thereof |
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| CN1896815A (en) * | 2005-08-31 | 2007-01-17 | 南京Lg同创彩色显示系统有限责任公司 | Current control device of liquid crystal display circulation device |
| CN101388184A (en) * | 2007-09-13 | 2009-03-18 | 北京京东方光电科技有限公司 | Method and apparatus for improving water noise of LCD |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1896815A (en) * | 2005-08-31 | 2007-01-17 | 南京Lg同创彩色显示系统有限责任公司 | Current control device of liquid crystal display circulation device |
| CN101388184A (en) * | 2007-09-13 | 2009-03-18 | 北京京东方光电科技有限公司 | Method and apparatus for improving water noise of LCD |
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