CN101520995B - Drive method of LCD backlight modules - Google Patents
Drive method of LCD backlight modules Download PDFInfo
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- CN101520995B CN101520995B CN2009101114051A CN200910111405A CN101520995B CN 101520995 B CN101520995 B CN 101520995B CN 2009101114051 A CN2009101114051 A CN 2009101114051A CN 200910111405 A CN200910111405 A CN 200910111405A CN 101520995 B CN101520995 B CN 101520995B
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Abstract
The invention relates to a drive method of LCD backlight modules, which is characterized in that a first operating current with fixed value is provided within a first scheduled period to adjust the brThe invention relates to a drive method of LCD backlight modules, which is characterized in that a first operating current with fixed value is provided within a first scheduled period to adjust the brightness of a backlight from a first brightness to a second brightness; and after the brightness of the backlight reaches the second brightness, a second operating current with a pulse form is provideightness of a backlight from a first brightness to a second brightness; and after the brightness of the backlight reaches the second brightness, a second operating current with a pulse form is provided within a second scheduled period for the backlight to improve the dynamic fuzzy. d within a second scheduled period for the backlight to improve the dynamic fuzzy.
Description
Technical field
The present invention is relevant to a kind of driving method of LCD backlight module, refers to a kind of driving method that can improve the LCD backlight module of dynamic fuzzy especially.
Technical background
LCD (Liquid Crystal Display, LCD) have that external form is frivolous, power consumption is few and a characteristic such as radiationless pollution, (personal digitalassistant PDA) waits on the information product to be widely used in computer system, mobile phone, personal digital assistant.LCD is to utilize the rotation that changes liquid crystal to control the amount of penetrating of light, to show the GTG of different brightness.(LCD then is to use voltage to keep the type of drive of (hold-type) continuously for cathode ray tube, the CRT) display mode of display use pulsed (impulse-type) compared to cathode-ray tube (CRT).Because liquid crystal rotates to be continuous variation, therefore slow than cathode-ray tube display on the reaction velocity of animate, so LCD picture when showing mobile object is easy to generate the phenomenon of dynamic fuzzy (motionblur).In order to solve the problem of dynamic fuzzy, generally can in LCD, use black plug (black insertion) technology to simulate the display mode of cathode-ray tube display.
In the given data black insertion technology, the backlight liquid crystal display module is to adopt whole the backlight that formula is lighted, utilize driving circuit to change data quantity adding black picture, that is to insert the GTG value between adjacent frames (frame) termly be 0 or the subgraph frame of relatively low GTG value.Under the situation that module backlight continues to light, because the liquid crystal reaction time is slow, the data black insertion technology only can improve the problem of dynamic fuzzy slightly, and can derive problems such as film flicker and luminance shortage.Simultaneously, oversize because of the signal transmission path of data line possibly when using the data black insertion technology on large-sized LCD, and produce problems such as electromagnetic interference (EMI) or signal degradation.
In known flicker backlight (blanking backlight) black insertion technology, the backlight liquid crystal display module is to adopt whole flicker backlight, under the situation that does not change data quantity, adds black picture in the mode of closing backlight.Flicker backlight black insertion technology can improve the problem of dynamic fuzzy, but can derive problems such as film flicker, ghost (ghost image) phenomenon and luminance shortage.
In known scanning type backlight (scanning backlight) black insertion technology, the backlight liquid crystal display module is to adopt the partly flickering backlight, and under the situation that does not change data quantity, the mode of backlight adds black picture to close partly.Because backlight changes the mode of P-SCAN and the data quantity synchronous scanning of liquid crystal into, treat to light with corresponding block backlight again when liquid crystal is reached stable state, therefore can improve problems such as dynamic fuzzy, film flicker, ghost phenomenon, but still have problems such as slight film flicker and luminance shortage.
Please refer to Fig. 1, the oscillogram of Fig. 1 has illustrated the running of one scan formula module backlight in the prior art.In Fig. 1, S1 represents the sweep signal of backlight, and D is the responsibility cycle (duty cycle) of signal S1, and T is the cycle of signal S1.Signal IL represents the operating current of backlight, and signal LS represents the brightness of backlight, and Tr is the brightness rise time, and Tf is brightness fall time.Signal S1 is used for controlling the unlatching of backlight and closing, and the time ratio that backlight is opened and closed is then determined by responsibility cycle D.When signal S1 opened backlight, fluorescent tube needed elapsed time Tr could arrive stable brightness; When signal S1 closed backlight, fluorescent tube needed elapsed time Tf to grow dark completely.General common use fluorescent lamp is used as Backlight For Liquid Crystal Display Panels, hot-cathode fluorescent light tube (hot cathode fluorescent lamp for example, HCFL) and the cold cathode fluorescent lamp pipe (cold cathode fluorescent lamp, CCFL), its light reaction velocity is slower.With the cold cathode fluorescent lamp pipe is example, and each about 3 milliseconds of its photopolymerization initiation time (relative brightness 10% rises to 90%) and optical attenuation times, the time that reaches stable state owing to fluorescent tube is longer, makes the effect of improving dynamic fuzzy be restricted.
Summary of the invention
The invention provides a kind of driving method of LCD backlight module, this method can shorten the brightness rise time and the fall time of backlight lighting tube, helps significantly improving dynamic fuzzy.
Method of the present invention is achieved in that one first operating current that the tool fixed value is provided is to transfer to one second brightness with a back light source brightness by one first brightness in one first scheduled period; And after the brightness of this backlight reached this second brightness, one second operating current that the tool impulse form was provided in one second scheduled period was to this backlight.
Remarkable advantage of the present invention is reasonable in design, is skillfully constructed, and can shorten the brightness rise time and the fall time of backlight lighting tube, helps significantly improving dynamic fuzzy.
Description of drawings
Fig. 1 is the oscillogram when one scan formula module backlight operates in the prior art.
Fig. 2 is the sequential chart of a kind of scanning backlight module unit driving method in the first embodiment of the invention.
Fig. 3 is the sequential chart of a kind of scanning backlight module unit driving method in the second embodiment of the invention.
Fig. 4 is the sequential chart of a kind of scanning backlight module unit driving method in the third embodiment of the invention.
[main element symbol description]
The S1 sweep signal
The IL operating current
TON_R, TON_F opening time
TOFF_R, TOFF_F shut-in time
The Tr brightness rise time
Tf brightness fall time
The D responsibility cycle
T, TON, TOFF, T1～T4 cycle
Xr, Yr, Xf, Yf, LS brightness
Embodiment
In the middle of instructions and follow-up claim, used some vocabulary to censure specific element.The person with usual knowledge in their respective areas should understand, and same element may be called with different nouns by manufacturer.This instructions and follow-up claim are not used as the mode of distinct elements with the difference of title, but the benchmark that is used as distinguishing with the difference of element on function.Be to be an open term mentioned " comprising " in the middle of the instructions in the whole text, so should be construed to " comprise but be not limited to ".
Use the fixedly sweep signal S1 of responsibility cycle compared to prior art, the present invention adjusts sweep signal according to the light characteristic of scanning backlight module fluorescent tube, after backlight module group lamp tube was opened a period of time, the present invention can close and open backlight module group lamp tube alternately according to a preset frequency.Please refer to Fig. 2, Fig. 2 is the sequential chart of a kind of scanning backlight module unit driving method in the first embodiment of the invention.S1 represents the sweep signal of backlight in Fig. 2, and signal IL represents the operating current of backlight, and signal LS represents the brightness of backlight.By the family curve of lighting tube brightness among Fig. 1 and Fig. 2 as can be known, the period T of signal S1 comprises one opens period T ON and and closes period T OFF, and in each opened period T ON, the wave mode of signal LS respectively comprised a rapid reaction period T 1 and a slow reaction period T 2.When unlatching period T ON was initial, the fluorescent tube of module backlight was in the rapid reaction period T 1, and this moment, the light reaction velocity was very fast, and backlight module group lamp tube brightness meeting is risen apace; After opening a period of time, the fluorescent tube of module backlight enters slow reaction period T 2, and this moment, the light reaction velocity was slack-off, and backlight module group lamp tube brightness meeting is risen lentamente.When slow reaction period T 2, backlight module group lamp tube brightness promotes limited, but significantly elongates to reach the required brightness rise time Tr of stable state.
Therefore, unlatching period T ON at backlight module group lamp tube, first embodiment of the invention when rapid reaction period T 1 with tool fixedly the sweep signal S1 of noble potential come driven sweep formula module backlight, the sweep signal S1 that changes when slow reaction period T 2 with impulse form comes driven sweep formula module backlight.When rapid reaction period T 1, the opening time of sweep signal S1 is represented by T1 equally; When slow reaction period T 2, opening time and the shut-in time of pulse sweep signal S1 are represented by TON_R and TOFF_R respectively.As shown in Figure 2, backlight module group lamp tube is unlatching in rapid reaction period T 1, therefore can promote Xr to a predetermined luminance apace.After entering slow reaction period T 2, the sweep signal S1 of impulse form at first closes fluorescent tube, and this moment, lighting tube brightness can be successively decreased gradually by predetermined luminance, is being Yr through attenuation amplitude behind the TOFF_R.Excessive in order not allow lighting tube brightness depart from predetermined value, the sweep signal S1 of impulse form can open fluorescent tube once more, and this moment, lighting tube brightness can increase progressively gradually, is reaching predetermined luminance again through behind the TON_R.
First embodiment of the invention can decide fluorescent tube opening time TON_R, T1 and shut-in time TOFF_R according to fluorescent tube characteristic and operating conditions.For instance, if wish the brightness rise time is foreshortened to T1, can learn according to light reaction rate to reach the required Xr value of predetermined luminance.Simultaneously, the wave mode shock range of wishing signal LS between the steady state period behind the T1 is less than 1/10, that is Yr/Xr＜1/10, thus opening time TON_R and shut-in time TOFF_R is neither can be greater than T1/10.First embodiment of the invention can all be made as T1/10 with each shut-in time TOFF_R of sweep signal S1 of impulse form.On the other hand, if consider the nonlinearities change of particle decay (particle decay) in the fluorescent tube characteristic, then can add a characterisitic parameter P, each shut-in time TOFF_R of sweep signal S1 of impulse form is reduced gradually, for example the shut-in time is T1/ (10-4P/5) for the first time behind T1, shut-in time is T1/ (10-3P/5) for the second time ..., the rest may be inferred.First embodiment of the invention is adjusted sweep signal S1 at the characteristic of fluorescent tube, when rapid reaction period T 1 with tool fixedly the sweep signal S1 of noble potential come driven sweep formula module backlight, significantly shorten the characteristic rise time of light; The sweep signal S1 that changes when slow reaction period T 2 with impulse form comes driven sweep formula module backlight, makes the light family curve can maintain predetermined luminance, therefore can significantly improve dynamic fuzzy.
Please refer to Fig. 3, Fig. 3 is the sequential chart of a kind of scanning backlight module unit driving method in the second embodiment of the invention.S1 represents the sweep signal of backlight in the 3rd figure, and signal IL represents the operating current of backlight, and signal LS represents the brightness of backlight.By the family curve of lighting tube brightness among Fig. 1 and Fig. 3 as can be known, the period T of signal S1 comprises one opens period T ON and and closes period T OFF, and in each closed period T OFF, the wave mode of signal LS respectively comprised a rapid reaction period T 3 and a slow reaction period T 4.Close period T OFF when initial, the fluorescent tube of module backlight is in the rapid reaction period T 3, and this moment, the light reaction velocity was very fast, and backlight module group lamp tube brightness can descend apace; After closing a period of time, the fluorescent tube of module backlight enters slow reaction period T 4, and this moment, the light reaction velocity was slack-off, and backlight module group lamp tube brightness descends lentamente.When slow reaction period T 4, backlight module group lamp tube brightness descends limited, but significantly elongates to reach required brightness Tf fall time of stable state.
Therefore, close period T OFF at backlight module group lamp tube, second embodiment of the invention when rapid reaction period T 3 with tool fixedly the sweep signal S1 of electronegative potential come driven sweep formula module backlight, the sweep signal S1 that changes when slow reaction period T 4 with impulse form comes driven sweep formula module backlight.When rapid reaction period T 3, the shut-in time of sweep signal S1 is represented by T3 equally; When slow reaction period T 4, opening time and the shut-in time of pulse sweep signal S1 are represented by TON_F and TOFF_F respectively.As shown in Figure 3, backlight module group lamp tube is in rapid reaction period T 3 closes, and therefore can reduce Xf to a predetermined luminance apace.After entering slow reaction period T 4, the sweep signal S1 of impulse form at first opens fluorescent tube, and this moment, lighting tube brightness can be increased gradually by predetermined luminance, is being Yf through increasing degree behind the TON_F.Excessive in order not allow lighting tube brightness depart from predetermined value, the sweep signal S1 of impulse form can close fluorescent tube once more, and this moment, lighting tube brightness descended once more, is reaching predetermined luminance again through behind the TOFF_F.
Second embodiment of the invention can decide fluorescent tube opening time TON_F, T3 and shut-in time TOFF_F according to fluorescent tube characteristic and operating conditions.For instance, if wish brightness is foreshortened to T3 fall time, can learn according to light reaction rate to reach the required Xf value of predetermined luminance.Simultaneously, the wave mode shock range of wishing signal LS between the steady state period behind the T3 is less than 1/10, that is Yf/Xf＜1/10, thus opening time TON_F and shut-in time TOFF_F is neither can be greater than T3/10.Second embodiment of the invention can all be made as T3/10 with each opening time TON_F of sweep signal S1 of impulse form.On the other hand, if consider the nonlinearities change of particle cumlative energy in the fluorescent tube characteristic, then can add a characterisitic parameter P, each opening time TON_F of sweep signal S1 of impulse form is reduced gradually, for example the opening time is T1/ (10-4P/5) for the first time behind T3, opening time is T1/ (10-3P/5) for the second time ..., the rest may be inferred.Second embodiment of the invention is closed period T OFF at the characteristic of fluorescent tube, when rapid reaction period T 3 with tool fixedly the sweep signal S1 of electronegative potential come driven sweep formula module backlight, significantly shorten light characteristic fall time; The sweep signal S1 that changes when slow reaction period T 4 with impulse form comes driven sweep formula module backlight, makes the light family curve can maintain predetermined luminance, therefore can significantly improve dynamic fuzzy.
Please refer to Fig. 4, Fig. 4 is the sequential chart of a kind of scanning backlight module unit driving method in the third embodiment of the invention.S1 represents the sweep signal of backlight in Fig. 4, and signal IL represents the operating current of backlight, and signal LS represents the brightness of backlight.Third embodiment of the invention is carried out aforementioned first and second embodiment simultaneously, unlatching period T ON at backlight lighting tube, third embodiment of the invention when rapid reaction period T 1 with tool fixedly the sweep signal S1 of noble potential come driven sweep formula module backlight, the sweep signal S1 that changes when slow reaction period T 2 with impulse form comes driven sweep formula module backlight.Close period T OFF at backlight lighting tube, third embodiment of the invention when rapid reaction period T 3 with tool fixedly the sweep signal S1 of electronegative potential come driven sweep formula module backlight, the sweep signal S1 that changes when slow reaction period T 4 with impulse form comes driven sweep formula module backlight.The running of third embodiment of the invention and light family curve LS and aforementioned first and second embodiment are similar, do not add in addition at this and give unnecessary details.Simultaneously, third embodiment of the invention also can decide fluorescent tube opening time TON_R, TON_F, T1 and shut-in time TOFF_R, TOFF_F, T3 according to fluorescent tube characteristic and operating conditions, therefore can significantly improve dynamic fuzzy.
The present invention adjusts sweep signal according to the light characteristic of scanning backlight module fluorescent tube, after backlight module group lamp tube is opened a period of time, the present invention can close and open backlight module group lamp tube alternately according to a preset frequency, therefore can shorten the brightness rise time and the fall time of backlight lighting tube, significantly improve dynamic fuzzy.
The above only is preferred embodiment of the present invention, and all equalizations of being done according to the present patent application claim change and modify, and all should belong to covering scope of the present invention.
Claims (7)
1. the driving method of a LCD backlight module is characterized in that:
Provide in the rapid reaction period T 1 in the unlatching cycle of backlight module group lamp tube tool fixedly the sweep signal S1 of noble potential be climbed to one second brightness with brightness from one first brightness with a backlight; And
After the brightness of this backlight reached this second brightness from this first brightness, the sweep signal S1 that impulse form is provided in the slow reaction period T 2 in the unlatching cycle of backlight module group lamp tube was to drive this module backlight.
2. the driving method of LCD backlight module according to claim 1 is characterized in that:
Reach the required time of this second brightness according to this backlight by this first brightness and set this rapid reaction period T 1.
3. the driving method of LCD backlight module according to claim 1, it is characterized in that: be set in open period and the down periods of the sweep signal S1 of these impulse forms in this slow reaction period T 2 according to this second brightness and one first brightness running parameter, wherein this first brightness running parameter is relevant to the ratio of this first brightness and this second brightness.
4. the driving method of LCD backlight module according to claim 1 is characterized in that:
Be set in open period and the down periods of the sweep signal S1 of these impulse forms in this slow reaction period T 2 according to a characterisitic parameter of this backlight, wherein this characterisitic parameter is relevant to the particle decay characteristic of this backlight.
5. the driving method of LCD backlight module according to claim 1 is characterized in that:
Closing of backlight module group lamp tube provide in the rapid reaction period T 3 in the cycle tool fixedly the sweep signal S1 of electronegative potential drop to this first brightness with brightness fast from this second brightness with this backlight; And
When the brightness of this backlight when this second brightness reaches this first brightness, provide the sweep signal S1 of impulse form to drive this module backlight closing in the slow reaction period T 4 in the cycle of backlight module group lamp tube.
6. the driving method of LCD backlight module according to claim 5 is characterized in that:
Reach the required time of this first brightness according to this backlight by this second brightness and set this rapid reaction period T 3, be set in open period and the down periods of the sweep signal S1 of these impulse forms in this slow reaction period T 4 according to this first brightness and one second brightness running parameter, wherein this second brightness running parameter is relevant to the ratio of this first brightness and this second brightness.
7. the driving method of LCD backlight module according to claim 5 is characterized in that:
Be set in open period and the down periods of the sweep signal S1 of these impulse forms in this slow reaction period T 4 according to a characterisitic parameter of this backlight, wherein this characterisitic parameter is relevant to the particle decay characteristic of this backlight or the particle cumlative energy characteristic of this backlight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101114051A CN101520995B (en) | 2009-04-02 | 2009-04-02 | Drive method of LCD backlight modules |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009101114051A CN101520995B (en) | 2009-04-02 | 2009-04-02 | Drive method of LCD backlight modules |
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| CN101520995A CN101520995A (en) | 2009-09-02 |
| CN101520995B true CN101520995B (en) | 2011-02-16 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105405407A (en) * | 2014-09-12 | 2016-03-16 | 群创光电股份有限公司 | Display device and backlight drive method thereof |
| TWI721375B (en) * | 2019-02-22 | 2021-03-11 | 友達光電股份有限公司 | Timing controller, display device and screen displaying method |
| CN114023275B (en) * | 2021-11-29 | 2022-09-27 | Tcl华星光电技术有限公司 | Driving method and driving device of backlight module |
| CN115032833A (en) * | 2022-05-26 | 2022-09-09 | 武汉华星光电技术有限公司 | Display device |
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Effective date of registration: 20130604 Address after: 350015 No. 1 Xingye Road, Mawei Science Park, Fujian, Fuzhou Patentee after: CPTF Optronics Co., Ltd. Address before: 350015 No. 1 Xingye Road, Mawei Science Park, Fujian, Fuzhou Patentee before: CPTF Optronics Co., Ltd. Patentee before: Chunghwa Picture Tubes Ltd. |
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