CN101751862A - Device for controlling luminance of backlight source and control method thereof - Google Patents
Device for controlling luminance of backlight source and control method thereof Download PDFInfo
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- CN101751862A CN101751862A CN200810219476A CN200810219476A CN101751862A CN 101751862 A CN101751862 A CN 101751862A CN 200810219476 A CN200810219476 A CN 200810219476A CN 200810219476 A CN200810219476 A CN 200810219476A CN 101751862 A CN101751862 A CN 101751862A
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Abstract
The invention discloses a device for controlling luminance of a backlight source and a controlling method thereof, wherein the control method of the luminance of the backlight source is used for providing a pulse-width modulation signal to a backlight control circuit so that the backlight control circuit can control the luminance of the backlight source to change progressively. The control method comprises the following steps of: firstly, setting a target duty cycle of the pulse-width modulation signal; then changing the duty cycle of the pulse-width modulation signal, wherein the changing magnitude is smaller than an absolute value of the differential value of the target duty cycle and the initial duty cycle of the pulse-width modulation signal, and providing the pulse-width modulation signal to the backlight control circuit; judging whether the duty cycle of the pulse-width modulation signal reaches the target duty cycle or not, if so, continuously providing the pulse-width modulation signal to the backlight control circuit, and if not, repeating the previous steps. The invention has the effect on that the progressive adjustment of the luminance of the backlight source can prevent the eyes of a user from discomfort caused by the instant changing of the pictures, and add the aesthetics visually.
Description
[technical field]
The invention relates to a kind of back light source brightness control method, be meant a kind of screen backlight source brightness control method especially with pulse-width modulation signal controlling screen backlight.
[background technology]
Various now electronic installations are LCD for example, portable navigation device (Portable NavigationDevice, PND) cathode fluorescent tube (Cold CathodeFluorescent Lamp is adopted in etc. screen backlight source more, CCFL) and two kinds of light emitting diodes (LED), and in the method for many LED-backlit source brilliance control, wherein a kind of is to utilize pulse width modulation (Pulse Width Modulation, PWM) technology is finished, the principle of its control is by a System on Chip/SoC (System-on-a-Chip, SoC) provide a pulse-width modulation signal and power supply to a backlight control IC, make responsibility cycle (duty cycle) difference adjustment export the size of current in LED-backlit source to, and then control and keep the brightness of backlight according to the pulse-width modulation signal.And when the control backlight from closing (OFF) to unlatching when (ON), System on Chip/SoC is directly to provide the pulse-width modulation signal of the required brightness of the corresponding backlight of its responsibility cycle and power supply to backlight control IC, make and directly light backlight, and in the time will closing backlight, System on Chip/SoC then stops the output pulse width modulating signal and power supply is given backlight control IC, and backlight is extinguished.Yet this kind control mode makes backlight bright or dark from bright commentaries on classics from blackout quickly, causes user's eyes not feel well easily, and visually also very not attractive in appearance.
[summary of the invention]
Therefore, purpose of the present invention is promptly providing a kind of back light source brightness control method that can the progressive adjustments back light source brightness.
So back light source brightness control method of the present invention is in order to providing a pulse-width modulation signal to a backlight control circuit, the brightness that makes this backlight control circuit control a backlight changes progressively, and the method includes the steps of:
(a) set a target responsibility cycle of this pulse-width modulation signal;
(b) change the responsibility cycle of this pulse-width modulation signal, and the change amount is less than the absolute value of target responsibility cycle with the difference of initial responsibility cycle of this pulse-width modulation signal, and provides this pulse-width modulation signal to this backlight control circuit;
(c) whether the responsibility cycle of judging this pulse-width modulation signal reaches the target responsibility cycle, if, execution in step (d), otherwise repeating step (b); And
(d) provide this pulse-width modulation signal to this backlight control circuit.
Compared with prior art, effect of the present invention is, the brightness of gradual adjustment backlight can be avoided user's eyes can not feel well because of the picture instantaneous variation, and can increase visual attractive in appearance again.
For purpose of the present invention, structural attitude and function thereof are had further understanding, conjunction with figs. is described in detail as follows now:
[description of drawings]
Fig. 1 is a circuit box synoptic diagram, and the preferred embodiment of backlight luminance control apparatus of the present invention is described.
Fig. 2 is a process flow diagram, and back light source brightness control method of the present invention is described.
[embodiment]
Consult Fig. 1, preferred embodiment for backlight luminance control apparatus of the present invention, this control device 1 mainly is the screen backlight source that is applied to electronic installation 2, for example LCD, portable navigation device (PortableNavigation Device, PND) etc., give backlight control circuit 3 in order to produce a pulse-width modulation signal, make it can adjust the brightness of backlight 4 progressively.Control device 1 of the present invention can be integrated in a System on Chip/SoC (System-on-a-Chip, SoC), wherein and comprise a control module 11 and a pulse-width modulation module (Pulse Width Modulation, PWM) 12.Control module 11 is coupled to pulse-width modulation module 12, and control pulse-width modulation module 12 produces a pulse-width modulation signal, and backlight control circuit 3 is coupled to pulse-width modulation module 12, and, the brightness of the backlight 4 that is coupled to backlight control circuit 3 is adjusted according to the responsibility cycle (duty cycle) of this pulse-width modulation signal.In the present embodiment, the responsibility cycle of pulse-width modulation signal is directly proportional with brightness, that is to say that the big more then brightness of responsibility cycle is high more, certainly, the responsibility cycle of pulse-width modulation signal and the brightness relation that also can be inversely proportional to, the more little then brightness of responsibility cycle is high more, does not exceed with present embodiment.
Consult Fig. 2, back light source brightness control method of the present invention can be realized by a software program that is stored in the computer-readable medium storing (for example being located at the flash memory (flash) in the control device 1), for reading in the control module 1 and load and execution.Since the backlight 4 of electronic installation 2 from the control principle that reaches passs (its brightness from bright to complete dark) open from closing to backlight 4 (its brightness from entirely secretly to bright) identical, so followingly will from closing to come the control flow of control module 1 be described with backlight 4.
What deserves to be mentioned is, in the above-mentioned steps 51, the target responsibility cycle of pulse-width modulation signal is not with 50% exceeding that present embodiment is supposed, it can be a preceding electronic installation 2 in use, the responsibility cycle of the pairing pulse-width modulation signal of backlight 4 brightness, for instance, if be that responsibility cycle at the pulse-width modulation signal is to be closed under 60% backlight 4 brightness before the electronic installation 2, then control module 11 can be before the power supply disappearance, in buffer, the target responsibility cycle is set at 60%, therefore when electronic installation 2 was unlocked again, its backlight 4 was 60% o'clock brightness through the responsibility cycle that will be set to the pulse-width modulation signal after the above-mentioned steps 51～53.
In addition, the initial responsibility cycle of pulse-width modulation signal is 0%, and recruitment each time is 1%, that is to say that the pulse-width modulation signal can go through 50 times modulation, its responsibility cycle just can reach the target responsibility cycle, and in the process that increases progressively, the brightness of backlight 4 also can be gradually bright along with the increase of responsibility cycle, thus user's eyes do not have because of backlight 4 quickly from the bright discomfort that causes of blackout.Certainly, the recruitment of each responsibility cycle can be inversely proportional to the number of times of going through modulation, and for example each responsibility cycle increases by 2%, then only needs 25 times modulation can reach the target responsibility cycle.In addition, the recruitment of responsibility cycle also can be neither identical at every turn, but no matter be to use which kind of method, total the credit union of its recruitment is all the absolute value of target responsibility cycle with the difference of initial responsibility cycle of pulse-width modulation signal.
Similarly, backlight 4 at electronic installation 2 is closed from being opened to, also can be by the way, just the target responsibility cycle of pulse-width modulation signal is 0%, and the responsibility cycle of pulse-width modulation signal can be decremented to 0% from certain certain value (responsibility cycle of the pulse-width modulation signal of correspondence when being backlight 4 unlatchings), and backlight 4 brightness meetings are gradually dark along with the minimizing of responsibility cycle, so the user also can not feel well because of the instantaneous variation of picture brightness.In addition, back light source brightness control method of the present invention not only is used for two states that backlight 4 switches between opening and closing, also can be used for when electronic installation 2 enters battery saving mode and makes backlight 4 brightness deteriorations, as long as the target responsibility cycle of pulse-width modulation signal is changed, control module 11 all can utilize control method of the present invention, and gradual change backlight 4 is to brightness that should the target responsibility cycle.
In sum, back light source brightness control method of the present invention is by the responsibility cycle of gradual change pulse-width modulation signal, make backlight to adjust along with responsibility cycle gradually, not only do not have the discomfort that causes user's eyes because of backlight moment change brightness, more increased attractive in appearance yet.
Claims (14)
1. back light source brightness control method, in order to provide a pulse-width modulation signal to a backlight control circuit, the brightness that makes this backlight control circuit control a backlight changes progressively, it is characterized in that, and the method includes the steps of:
(a) set a target responsibility cycle of this pulse-width modulation signal;
(b) change the responsibility cycle of this pulse-width modulation signal, and the change amount is less than the absolute value of target responsibility cycle with the difference of initial responsibility cycle of this pulse-width modulation signal, and provides this pulse-width modulation signal to this backlight control circuit;
(c) whether the responsibility cycle of judging this pulse-width modulation signal reaches this target responsibility cycle, if, execution in step (d), otherwise repeating step (b); And
(d) continue to provide this pulse-width modulation signal to this backlight control circuit.
2. back light source brightness control method as claimed in claim 1 is characterized in that, the initial responsibility cycle of this pulse-width modulation signal is zero, and it controls this back light source brightness for complete dark, and this target responsibility cycle is controlled this backlight and produced a predetermined luminance.
3. back light source brightness control method as claimed in claim 1, it is characterized in that the initial responsibility cycle of this pulse-width modulation signal is a certain value, it controls this back light source brightness is a brightness, and this target responsibility cycle is zero, and it controls this back light source brightness for complete dark.
4. back light source brightness control method as claimed in claim 1, it is characterized in that the initial responsibility cycle of this pulse-width modulation signal is a certain value, it controls this back light source brightness is one first brightness, and this target responsibility cycle is another definite value, and it controls this back light source brightness is one second brightness.
5. back light source brightness control method as claimed in claim 1, it is characterized in that, in its step (b), if this target responsibility cycle is greater than this initial responsibility cycle, then the responsibility cycle of this pulse-width modulation signal is increased, if this target responsibility cycle is less than this initial responsibility cycle, then the responsibility cycle of this pulse-width modulation signal is reduced.
6. as each described back light source brightness control method in the claim 1-5 item, it is characterized in that, during each execution in step (b), the change amount of this pulse-width modulation signal is a certain value, and the definite value sum total behind the certain number of times of repeating step (b) is the absolute value of target responsibility cycle with the difference of initial responsibility cycle of this pulse-width modulation signal.
7. as each described back light source brightness control method in the claim 1-5 item, it is characterized in that, during each execution in step (b), the change amount of this pulse-width modulation signal is the change value, and the change amount sum total behind the certain number of times of repeating step (b) is the absolute value of target responsibility cycle with the difference of initial responsibility cycle of this pulse-width modulation signal.
8. back light source brightness control method as claimed in claim 6 is characterized in that, in its step (b), the change amount of this pulse-width modulation signal is 1%.
9. a backlight luminance control apparatus in order to provide a pulse-width modulation signal to a backlight control circuit, makes the brightness of controlling a backlight progressively, it is characterized in that this backlight luminance control apparatus comprises:
One pulse-width modulation module is in order to produce a pulse-width modulation signal; And
One control module is coupled to this pulse-width modulation module, and controls this pulse-width modulation module, and this pulse-width modulation signal is changed progressively from an initial responsibility cycle, reaches a target responsibility cycle up to the responsibility cycle of this pulse-width modulation signal.
10. backlight luminance control apparatus as claimed in claim 9 is characterized in that, the each change amount of the pulse-width modulation signal that this pulse-width modulation module is produced is less than the absolute value of target responsibility cycle with the difference of initial responsibility cycle of this pulse-width modulation signal.
11. backlight luminance control apparatus as claimed in claim 9, it is characterized in that, the initial responsibility cycle of this pulse-width modulation signal that this control device sent is a certain value, it controls this back light source brightness is one first brightness, and this target responsibility cycle is another definite value, and it controls this back light source brightness is one second brightness.
12. backlight luminance control apparatus as claimed in claim 9, it is characterized in that, if this target responsibility cycle is greater than this initial responsibility cycle, then this control module can be controlled the responsibility cycle increase of this pulse-width modulation signal, if this target responsibility cycle is less than this initial responsibility cycle, then this control module can be controlled the responsibility cycle minimizing of this pulse-width modulation signal.
13. as each described backlight luminance control apparatus in the claim 9-13 item, it is characterized in that, this control module is a certain value to the change amount of this pulse-width modulation signal at every turn, and repeats the absolute value of the change amount sum total of certain number of times for target responsibility cycle with the difference of initial responsibility cycle of this pulse-width modulation signal.
14. as each described backlight luminance control apparatus in the claim 9-13 item, it is characterized in that, this control module is the change value to the change amount of this pulse-width modulation signal at every turn, and repeats the absolute value of the change amount sum total of certain number of times for target responsibility cycle with the difference of initial responsibility cycle of this pulse-width modulation signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810219476A CN101751862A (en) | 2008-11-28 | 2008-11-28 | Device for controlling luminance of backlight source and control method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810219476A CN101751862A (en) | 2008-11-28 | 2008-11-28 | Device for controlling luminance of backlight source and control method thereof |
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| CN101751862A true CN101751862A (en) | 2010-06-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN200810219476A Pending CN101751862A (en) | 2008-11-28 | 2008-11-28 | Device for controlling luminance of backlight source and control method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102403918A (en) * | 2010-09-07 | 2012-04-04 | 致茂电子(苏州)有限公司 | Power module and power supplier with same |
| CN104641310A (en) * | 2012-07-16 | 2015-05-20 | 西门子公司 | Process image of a technical system, in particular a railway track system |
| CN106448575A (en) * | 2016-11-09 | 2017-02-22 | 广州视源电子科技股份有限公司 | A backlight adjusting method and a backlight drive circuit |
-
2008
- 2008-11-28 CN CN200810219476A patent/CN101751862A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102403918A (en) * | 2010-09-07 | 2012-04-04 | 致茂电子(苏州)有限公司 | Power module and power supplier with same |
| CN104641310A (en) * | 2012-07-16 | 2015-05-20 | 西门子公司 | Process image of a technical system, in particular a railway track system |
| CN106448575A (en) * | 2016-11-09 | 2017-02-22 | 广州视源电子科技股份有限公司 | A backlight adjusting method and a backlight drive circuit |
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Open date: 20100623 |