CN101266345B - Backlight module and its drive method and LCD device - Google Patents
Backlight module and its drive method and LCD device Download PDFInfo
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- CN101266345B CN101266345B CN2007100857734A CN200710085773A CN101266345B CN 101266345 B CN101266345 B CN 101266345B CN 2007100857734 A CN2007100857734 A CN 2007100857734A CN 200710085773 A CN200710085773 A CN 200710085773A CN 101266345 B CN101266345 B CN 101266345B
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Abstract
A drive method of a backlight module is disclosed, wherein the backlight module has an impulse-width modulation unit and at least a luminous diode which is dived by a first impulse-width modulation signal corresponding to the first duty ratio. The drive method of the backlight module contains the following steps: detecting the light generated by luminous diodes to produce the signal value; comparison signal value and the desired value in order to produce the comparative result; regulating the first duty cycle and the second duty cycle according to the comparative result; producing a second impulse-width modulation signal according to the second duty cycle by the impulse-width modulation unit in order to drive the luminous diodes, wherein, the second duty cycle is substantively larger than75%.
Description
Technical field
The present invention relates to a kind of luminescence unit and driving method thereof and flat display apparatus, particularly a kind of backlight module and driving method and liquid crystal indicator.
Background technology
Along with showing development of science and technology, flat display apparatus and products thereof is used by people widely, and liquid crystal indicator is because of having that build is frivolous, low power consumption and advantageous characteristic such as radiationless, replace the conventional cathode ray tube display device gradually, and be applied to the electronic product of numerous species.
Please refer to liquid crystal indicator shown in Figure 1, known 1 and comprise a backlight module 11 and a display panels 12.Wherein, backlight module 11 mainly has one drive circuit 111 and at least one light emitting diode 112.Driving circuit 111 produce pulse-width signal PM with driven for emitting lights diode 112 so that it emits beam LT.Display panels 12 utilize the light LT that sent by light emitting diode 112 as backlight with display frame.
Yet, owing to the optical characteristics (for example colourity or briliancy etc.) of the light emitting diode 112 light LT that produces is understood along with the 112 employed times of light emitting diode produce change or decay, therefore, in order to address the above problem, the dealer develops a liquid crystal indicator 2.Please refer to liquid crystal indicator shown in Figure 2, known 2 and comprise a backlight module 21 and a display panels 22.Wherein, backlight module 21 has one drive circuit 211, at least one light emitting diode 212 and a photodetector 213, and driving circuit 211 has a pwm unit 2111 and an arithmetic element 2112.For instance, it is 50% pulse-width signal PM ' that pwm unit 2111 can produce dutycycle (duty ratio), with driven for emitting lights diode 212 LT ' that emits beam.The light LT ' that photodetector 213 detection light emitting diodes 212 are sent is to produce signal value SN ', arithmetic element 2112 calculates the error value E R ' between signal value SN ' and the desired value TT ', and exports pwm unit 2111 to adjust pulse-width signal PM '.Thus, promptly form the constantly pulse-width signal PM ' that produced of feedback modifiers pwm unit 2111 of closed loop (close loop).
In other words, it is that the pulse-width signal (not shown) sent a correction back light (not shown) with driven for emitting lights diode 212 after one of 50%+ Δ (Δ is an error amount, for example is 1%) was revised that pwm unit 2111 produces dutycycle according to error value E R '.At this moment, display panels 22 receives revises back light, with colourity or the briliancy of revising shown image.
Usually, has digitial controller (digital IC) in the driving circuit 211 usually, with control pwm unit 2111 and arithmetic element 2112.When adjusting the dutycycle of pulse-width signal PM ',, then can heal and revise the dutycycle of pulse-width signal PM ' accurately if adjustable unit scale is littler.For example: adjustable unit scale is that 0.1% o'clock precision promptly is 1% precision greater than adjustable unit scale, and relatively also can heal and revise colourity or briliancy accurately.
Yet, with regard to known liquid crystal indicator 2,, need the hardware (for example arithmetic element 2112) of higher arithmetic capability to cooperate if want to have less adjustable unit scale, thus, then can improve the cost of products of liquid crystal indicator 2.Therefore, how to provide a kind of hardware device that can not need higher arithmetic capability, but still a kind of backlight module and the driving method and the liquid crystal indicator of accuracy controlling light colourity or briliancy, real one of the current important topic that belongs to.
Summary of the invention
Because above-mentioned problem, purpose of the present invention still can be regulated and control the mould a kind of backlight of light colourity or briliancy more accurately and determine and driving method and liquid crystal indicator for a kind of hardware that can not need higher arithmetic capability is provided.
Therefore, for reaching above-mentioned purpose, driving method according to a kind of backlight module of the present invention, backlight module has pwm unit and at least one light emitting diode, light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence, and the driving method of backlight module comprises the following step: the detection light that light emitting diode sent is to produce signal value; Comparison signal value and desired value are to produce comparative result; Adjust first dutycycle to the second dutycycle according to comparative result; Produce second pulse-width signal with the driven for emitting lights diode by pwm unit according to second dutycycle, wherein second dutycycle is in fact greater than 75% and less than 100%.
In addition, for reaching above-mentioned purpose, comprise at least one light emitting diode according to a kind of backlight module of the present invention, one photodetector, one pwm unit and a comparing unit, wherein, light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence, the photodetector detection light that light emitting diode sent is to produce signal value, comparing unit comparison signal value and desired value are to produce comparative result, pwm unit is adjusted first dutycycle to the second dutycycle according to comparative result, and produce second pulse-width signal with the driven for emitting lights diode according to second dutycycle, wherein second dutycycle is in fact greater than 75% and less than 100%.
Moreover, for reaching above-mentioned purpose, comprise a backlight module and a display panels according to a kind of liquid crystal indicator of the present invention.Backlight module has at least one light emitting diode, one photodetector, one pwm unit and a comparing unit, wherein, light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence, the photodetector detection light that light emitting diode sent is to produce signal value, comparing unit comparison signal value and desired value are to produce comparative result, pwm unit is adjusted first dutycycle to the second dutycycle according to comparative result, and produce second pulse-width signal with the driven for emitting lights diode according to second dutycycle, wherein second dutycycle is in fact greater than 75% and less than 100%; The light that light emitting diode sent provides display panels to show required light source.
Again, for reaching above-mentioned purpose, driving method according to another kind of backlight module of the present invention, backlight module has pwm unit and at least one light emitting diode, light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence, and the driving method of backlight module comprises the following step: the detection light that light emitting diode sent is to produce signal value; Comparison signal value and desired value are to produce comparative result; Adjust first dutycycle to the second dutycycle according to comparative result; Judge second dutycycle, wherein if second dutycycle greater than 75% and less than 100% o'clock, produce second pulse-width signal with the driven for emitting lights diode by pwm unit according to second dutycycle, if second dutycycle was less than 75% o'clock, adjust second dutycycle to the, three dutycycles by pwm unit, and the 3rd dutycycle is greater than 75% and less than 100%, and produces the 3rd pulse-width signal with the driven for emitting lights diode by pwm unit according to the 3rd dutycycle.
In addition, for reaching above-mentioned purpose, comprise at least one light emitting diode according to another kind of backlight module of the present invention, one photodetector, one pwm unit, one comparing unit and a judging unit, wherein, light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence, the photodetector detection light that light emitting diode sent is to produce signal value, comparing unit comparison signal value and desired value are to produce comparative result, pwm unit is adjusted first dutycycle to the second dutycycle according to comparative result, judgment unit judges second dutycycle, wherein if second dutycycle greater than 75% and less than 100% o'clock, pwm unit produces second pulse-width signal with the driven for emitting lights diode according to second dutycycle, if second dutycycle was less than 75% o'clock, pwm unit is adjusted second dutycycle to the, three dutycycles, and the 3rd dutycycle is greater than 75% and less than 100%, and pwm unit produces the 3rd pulse-width signal with the driven for emitting lights diode according to the 3rd dutycycle.
Moreover, for reaching above-mentioned purpose, comprise a backlight module and a display panels according to another kind of liquid crystal indicator of the present invention.Backlight module has at least one light emitting diode, one photodetector, one pwm unit, one comparing unit and a judging unit, wherein, light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence, the photodetector detection light that light emitting diode sent is to produce signal value, comparing unit comparison signal value and desired value are to produce comparative result, pwm unit is adjusted first dutycycle to the second dutycycle according to comparative result, judgment unit judges second dutycycle, if second dutycycle is greater than 75% and less than 100% o'clock, pwm unit produces second pulse-width signal with the driven for emitting lights diode according to second dutycycle, if second dutycycle was less than 75% o'clock, pwm unit is adjusted second dutycycle to the, three dutycycles, and the 3rd dutycycle is greater than 75% and less than 100%, and pwm unit produces the 3rd pulse-width signal with the driven for emitting lights diode according to the 3rd dutycycle, and the light that light emitting diode sent provides display panels to show required light source.
From the above, according to backlight module of the present invention and driving method and liquid crystal indicator, compare with known techniques, pwm unit of the present invention can be with the dutycycle correction of generation pulse-width signal and is maintained at greater than 75% (be higher than known 50%), institute is so that backlight module of the present invention and driving method thereof and liquid crystal indicator, can the upgrade hardware arithmetic capability of pwm unit, still can accurately regulate and control light colourity or briliancy, and then save the cost of HardwareUpgring.
Description of drawings
Fig. 1 to Fig. 2 is a prescription piece synoptic diagram, shows known liquid crystal indicator;
Fig. 3 is a flow process synoptic diagram, shows the driving method of the backlight module of first embodiment of the invention;
Fig. 4, Fig. 7, Fig. 8 and Fig. 9 are a prescription piece synoptic diagram, displayed map 3 described backlight modules;
Fig. 5 is an experimental result, shows the relation of light emitting diode emitted light on time and briliancy;
Fig. 6 is an experimental result, shows the position relation of light emitting diode emitted light corresponding chromaticity coordinate under different time;
Figure 10 is a flow process synoptic diagram, shows the driving method of the backlight module of second embodiment of the invention;
Figure 11 and Figure 12 are a prescription piece synoptic diagram, show the described backlight module of Figure 10;
Figure 13 is a prescription piece synoptic diagram, shows the liquid crystal indicator of first embodiment of the invention; And
Figure 14 is a prescription piece synoptic diagram, shows the liquid crystal indicator of second embodiment of the invention.
The component symbol explanation:
1: liquid crystal indicator
11: backlight module
111: driving circuit
112: light emitting diode
12: display panels
2: liquid crystal indicator
21: backlight module
211: driving circuit
2111: pwm unit
2112: arithmetic element
212: light emitting diode
213: photodetector
22: display panels
3: liquid crystal indicator
31: backlight module
311: light emitting diode
3132: pwm unit
3131: comparing unit
3133: judging unit
3134: setup unit
312: photodetector
313: driving circuit
32: display panels
4: liquid crystal indicator
41: backlight module
42: display panels
411: light emitting diode
412: photodetector
413: driving circuit
4131: pwm unit
4132: comparing unit
4133: setup unit
C1: first current level
C1 ': current level
C2: second current level
C2 ': current level
C3: the 3rd current level
D1: first dutycycle
D1 ': first dutycycle
D2: second dutycycle
D2 ': second dutycycle
D3: the 3rd dutycycle
D4: the 4th dutycycle
ER ': error amount
E1, E1 ': comparative result
L1, L1 ', L2, L2 ': light
L3, L4, LT, LT ': light
P1: first pulse-width signal
P1 ': first pulse-width signal
P2: second pulse-width signal
P2 ': second pulse-width signal
P3: the 3rd pulse-width signal
P4: the 4th pulse-width signal
PM, PM ': pulse-width signal
S1, S1 ': signal value
CB, CB ': chromatic value or brightness value
SN ': signal value
T1, T1 ', TT ': desired value
ST31～ST37: the step of the driving method of backlight module
ST41～ST45: the step of the driving method of backlight module
Embodiment
Hereinafter with reference to relevant drawings, backlight module and driving method and liquid crystal indicator according to the embodiment of the invention are described, wherein components identical will be illustrated with identical reference marks.
First embodiment of the driving method of backlight module
Please be simultaneously with reference to Fig. 3 and shown in Figure 4, can comprise step ST31 to step ST37 according to the driving method of the backlight module of first embodiment of the invention.And backlight module 31 can comprise at least one light emitting diode 311, a photodetector 312, a comparing unit 3131, a pwm unit 3132, a judging unit 3133 and a setup unit 3134.Wherein, pwm unit 3132 can produce the first pulse-width signal P1 with driven for emitting lights diode 311 L1 that emits beam according to the first dutycycle D1 and the first current level C1.In the present embodiment, unit such as comparing unit 3131, pwm unit 3132, judging unit 3133 and setup unit 3134 constitute driving circuit 313.
In step ST31, produce desired value T1 according to chromatic value or brightness value CB.In the present embodiment, step ST31 produces desired value T1 by setup unit 3134 according to chromatic value or brightness value CB computing, and wherein, chromatic value or brightness value CB can be user's value of ordering certainly by external setting-up, are the preset value of product export perhaps.
In step ST32, the light L1 that detection light emitting diode 311 is sent is to produce signal value S1.In the present embodiment, step ST32 detects light L1 that light emitting diodes 311 are sent to produce signal value S1 to comparing unit 3131 by photodetector 312.Wherein signal value S1 can be magnitude of voltage, current value and maybe can represent the power of the signal (as: frequency) of light intensity with the corresponding photodetector 312 light L1 that detected.
In step ST33, be comparison signal value S1 and desired value T1 producing comparative result E1, and whether need to adjust the first dutycycle D1 according to comparative result E1 decision.In the present embodiment, step ST33 be by comparing unit 3131 comparison signal value S1 and desired value T1 producing comparative result E1, and whether need to adjust the first dutycycle D1 according to comparative result E1 decision by pwm unit 3132.For example, when comparative result E1 during (difference of expression signal value S1 and desired value T1 not quite or much at one) less than threshold value, then can be in execution in step ST33 after after a period of time, repeated execution of steps ST32 is once again.Otherwise, when comparative result E1 greater than threshold value, execution in step ST34 then.
In step ST34, be to adjust first dutycycle D1 to the second dutycycle D2 according to comparative result E1, for example if the first dutycycle D1 is that 90%, the second dutycycle D2 then is the 90%+ Δ, wherein comparative result E1 is many more greater than threshold value, and Δ is also big relatively more.In the present embodiment, step ST34 adjusts first dutycycle D1 to the second dutycycle D2 by pwm unit 3132 according to comparative result E1, also can adjust dutycycle by setup unit 3134 certainly, and present embodiment is an example with the former.Thus, promptly form the pulse-width signal P1 that a closed loop is produced with feedback modifiers pwm unit 3132.
Then, please refer to Fig. 5 to Fig. 6 so that two experimental results to be described.
Please refer to shown in Figure 5, it shows the relation of light emitting diode emitted light on time and briliancy, wherein, the first experiment group is to be about the light that 50% pwm unit driven for emitting lights diode sends with dutycycle, and the mean value of measuring light luminance variations amount in two hours is about 1.66%; The second experiment group is to be about the light that 60% pwm unit driven for emitting lights diode sends with dutycycle, and the mean value of measuring luminance variations amount in two hours is about 1.5%; The 3rd experiment group is to be about 90% pwm unit driven for emitting lights diode with dutycycle to emit beam, and the mean value of measuring luminance variations amount in two hours is about 0.5%.
By the experimental result of Fig. 5 as can be known, when if pwm unit emits beam with the higher pwm unit driven for emitting lights diode of dutycycle, the light that light emitting diode sent can have less luminance variations amount, that is to say, when dutycycle was higher, pwm unit can more accurately be regulated and control the brightness value of light.
Please refer to shown in Figure 6ly, it has shown the variation of light emitting diode emitted light corresponding chromaticity coordinate (CIE 1976 UCS chromatic diagrams) under long-time operation.Wherein, the first experiment group is to be about 50% pwm unit driven for emitting lights diode with dutycycle to emit beam, and the mean value (Δ u ' v ') of measuring light colourity variable quantity in two hours is 0.00378; The second experiment group is to be about 60% pwm unit driven for emitting lights diode with dutycycle to emit beam, and the mean value (Δ u ' v ') of measuring light colourity variable quantity in two hours is 0.00349; The 3rd experiment group is to be about with dutycycle that 90% pwm unit driven for emitting lights diode emits beam and the mean value (Δ u ' v ') of measuring light colourity variable quantity in two hours is 0.00193.
By the experimental result of Fig. 6 as can be known, when if pwm unit emits beam with the higher pwm unit driven for emitting lights diode of dutycycle, the light that light emitting diode sent can have less colourity variable quantity, that is to say, when dutycycle was higher, pwm unit can more accurately be regulated and control the chromatic value of light.
Comprehensive above-mentioned two result of experiment, if the present invention can make the dutycycle correction of pulse-width signal that pwm unit produces and be maintained under the higher ratio and (for example be higher than 75%), then can make pwm unit can more accurately regulate and control light colourity, briliancy.
Please be simultaneously with reference to Fig. 3 and shown in Figure 7, in step ST35, judging unit 3133 judges whether the second dutycycle D2 is lower than 75%, in the present embodiment, when if the second dutycycle D2 is 90% (greater than 75%, and less than 100%), execution in step ST36 then, step ST36 produces the second pulse-width signal P2 by pwm unit 3132 according to the second dutycycle D2 (greater than 75%, and less than 100%) to send revised light L2 with as backlight with driven for emitting lights diode 311.Afterwards, backlight module 31 can be at completing steps ST36 after a period of time, again repeated execution of steps ST32 once, to revise colourity or briliancy.
Otherwise, please be simultaneously with reference to Fig. 3 and shown in Figure 8, when if the second dutycycle D2 is 70% (less than 75%), execution in step ST37 then, it is to adjust first current level C1 to the second current level C2 by pwm unit 3132, and the second dutycycle D2 is adjusted to the 3rd dutycycle D3, wherein, the 3rd dutycycle D3 needs greater than 75%, and less than 100% (for example being 90%), and the first current level C1 needs greater than the second current level C2, and the preferably is: the product of the second current level C2 and the 3rd dutycycle D3 equals the product of the first current level C1 and the second dutycycle D2 in fact.Then, produce the 3rd pulse-width signal P3 by pwm unit 3132 according to the 3rd dutycycle D3 (greater than 75%, and less than 100%) again and send revised light L3 with as backlight with driven for emitting lights diode 311.Afterwards, backlight module 31 can be at completing steps ST37 after a period of time, repeated execution of steps ST32 is once again.
In addition, please be simultaneously with reference to Fig. 3 and shown in Figure 9, step ST35 judges except judging whether the second dutycycle D2 is lower than 75% by judging unit 3133, more can comprising by judging unit 3133 whether the second dutycycle D2 has reached 100%.Wherein, if judging unit 3133 judges that the second dutycycle D2 is at 100% o'clock, execution in step ST37 then, it is to adjust the first current level C1 to the, three current level C3 by pwm unit 3132, and adjust the second dutycycle D2 to the, four dutycycle D4, wherein, the 4th dutycycle D4 needs greater than 75%, and less than 100% (for example being 90%), and the 3rd current level C3 needs greater than the first current level C1, and the preferably is: the product of the 3rd current level C3 and the 4th dutycycle D4 equals the product of the first current level C1 and the second dutycycle D2 in fact.Then, pwm unit 3132 produces the 4th pulse-width signal P4 according to the 4th dutycycle D4 (greater than 75%, and less than 100%) and the 3rd current level C3 and sends with driven for emitting lights diode 311 and revise back light L4 with as backlight.Afterwards, backlight module 31 can be at completing steps ST37 after a period of time, repeated execution of steps ST32 is once again.
Hold, because of the driving method of backlight module of the present invention is with the dutycycle correction of generation pulse-width signal and maintains greater than 75% (be higher than known 50%), so that the driving method of backlight module of the present invention can be regulated and control light colourity or briliancy more accurately under the arithmetic capability of pwm unit of needn't upgrading.
In addition, driving method that it should be noted that backlight module of the present invention can also not given unnecessary details at this as the preposition step of regulation and control colour temperature in addition except regulating and control light colourity or briliancy.
Second embodiment of the driving method of backlight module
Please be simultaneously with reference to Figure 10 and shown in Figure 11, can comprise step ST41 to step ST45 according to the driving method of the backlight module of second embodiment of the invention.And backlight module 41 can comprise at least one light emitting diode 411, a photodetector 412, pwm unit 4131, a comparing unit 4132 and a setup unit 4133, wherein, pwm unit 4131 can produce the first pulse-width signal P1 ' with the driven for emitting lights diode L1 ' that emits beam according to the first dutycycle D1 ' and current level C1 '.In the present embodiment, unit such as pwm unit 4131, comparing unit 4132 and setup unit 4133 constitute driving circuit 413.
In step ST41, it produces desired value T1 ' according to chromatic value or brightness value CB '.Wherein, chromatic value or brightness value CB ' can be value of ordering certainly that the user sets up on their own, perhaps are the preset value of product export.In addition, step ST41 also can produce current level C2 ' according to chromatic value or brightness value CB ' except producing desired value T1 ' according to chromatic value or brightness value CB '.Wherein, current level C2 ' can be identical with current level C1 ', also can be different.In the present embodiment, step ST41 produces current level C2 ' by setup unit 4133 according to chromatic value or brightness value CB ', output current level C2 ' is to pwm unit 4131 again, perhaps step ST41 also can directly produce current level C2 ' according to chromatic value or brightness value CB ' by pwm unit 4131, and present embodiment is to be example with the former.
Then, execution in step ST42, the light L1 ' that its detection light emitting diode 411 is sent is to produce signal value S1 '.In the present embodiment, step ST42 detects the light L1 ' that light emitting diode 411 is sent by photodetector 412, to produce signal value S1 ' to comparing unit 4132.Wherein signal value S1 ' can be magnitude of voltage, current value and maybe can represent the power of the signal (as: frequency) of light intensity with the corresponding photodetector 412 light L1 ' that detected.
Then, execution in step ST43, its be comparison signal value S1 ' with desired value T1 ' producing comparative result E1 ', and whether need to adjust the first dutycycle D1 ' by comparative result E1 ' decision.In the present embodiment, step ST43 is to produce comparative result E1 ' by comparing unit 4132 comparison signal value S1 ' and desired value T1 ', and output comparative result E1 ' is to pwm unit 4131, and then whether need to adjust the first dutycycle D1 ' according to comparative result E1 ' decision by pwm unit 4131, for example, as comparative result E1 ' during less than threshold value, then at completing steps ST43 after by certain hour, repeated execution of steps ST42 again.Otherwise, when comparative result E1 ' greater than a threshold value, please be simultaneously with reference to Figure 10 and shown in Figure 12, execution in step ST44 then, it is to adjust the first dutycycle D1 ' to the second dutycycle D2 ' according to comparative result E1 ', and wherein, the second dutycycle D2 ' is greater than 75%, the preferably is: the second dutycycle D2 ' is greater than 75%, and less than 95%.For example, if the second dutycycle D2 ' is that 90%, the second dutycycle D2 ' then is the 90%+ Δ, wherein comparative result E1 ' is many more greater than threshold value, and Δ is also big relatively more.Thus, promptly form the pulse-width signal P1 ' (as shown in figure 11) that a closed loop is produced with follow-up feedback modifiers pwm unit 4131.
Therefore, behind completing steps ST44, execution in step ST45, it is to produce the second pulse-width signal P2 ' according to the second dutycycle D2 ' (greater than 75%, and less than 95%).In the present embodiment, step ST44 produces the second pulse-width signal P2 ' with driven for emitting lights diode 411 L2 ' that emits beam by pwm unit 4131 according to second dutycycle D2 ' (greater than 75%, and less than 95%) and current level C2 '.
Hold, because of the driving method of backlight module of the present invention is with the dutycycle correction of generation pulse-width signal and is maintained at greater than 75% (be higher than known 50%), so that the driving method of backlight module of the present invention can be regulated and control light colourity or briliancy more accurately under the arithmetic capability of pwm unit of needn't upgrading.
In addition, driving method that it should be noted that backlight module of the present invention is except regulating and control light colourity or briliancy, and also adjustable certainly colour temperature is not given unnecessary details at this.
First embodiment of backlight module
Please refer to shown in Figure 4ly, have at least one light emitting diode 311, a photodetector 312, a pwm unit 3132, a comparing unit 3131 and a judging unit 3133 according to the backlight module 31 of first embodiment of the invention.Wherein, the backlight module 31 of present embodiment describes in detail in the driving method of the backlight module of first embodiment of the invention, does not give unnecessary details at this.
In addition, it should be noted that, the driving circuit 313 of backlight module 31 more can comprise a setup unit 3134, produce desired value T1 with foundation chromatic value or brightness value CB, and in the present embodiment, pwm unit 3132, comparing unit 3131, judging unit 3133 and setup unit 3134 can be integrated into a microcontroller (MCU), and are respectively the mac function in the microcontroller.
Moreover, the driving circuit 313 of backlight module 31 more can comprise a converting unit (not shown), for example be a DC-DC rectifier (DC-DC converter), wherein, converting unit can electrically connect with pwm unit 3132 and light emitting diode 311 respectively, with pulse-width signal (P1, P2, P3 or P4) corresponding conversion that pwm unit 3132 is produced is a drive current, and perhaps driving voltage is with driven for emitting lights diode 311.
Again, light emitting diode 311 can be a red light-emitting diode, a green light LED or a blue light-emitting diode.Relatively, photodetector 312 can be a ruddiness detecting element, a green glow detecting element or a blue light detecting element, to detect the light that light emitting diode 311 is sent.In addition, signal value S1 can be a magnitude of voltage or the current value power with corresponding photodetector 312 light L1, L2, L3 or the L4 of being detected.
Hold, because of backlight module of the present invention is with the dutycycle correction of generation pulse-width signal and is maintained at greater than 75% (be higher than known 50%), under the arithmetic capability of pwm unit, still can regulate and control light colourity or briliancy more accurately so that backlight module of the present invention can be upgraded.
Second embodiment of backlight module
Please refer to shown in Figure 11ly, have at least one light emitting diode 411, a photodetector 412 1 pwm units 4131 and a comparing unit 4132 according to the backlight module 41 of second embodiment of the invention.Wherein, the backlight module 41 of present embodiment describes in detail in the driving method of the backlight module of second embodiment of the invention, does not give unnecessary details at this.
In addition, it should be noted that, the driving circuit 413 of backlight module 41 more can comprise a setup unit 4133, produce desired value T1 ' with foundation chromatic value or brightness value CB ', and in the present embodiment, pwm unit 4131, comparing unit 4132 and setup unit 4133 can be integrated into a microcontroller (MCU), and are respectively the mac function in the microcontroller.
Moreover, the driving circuit 413 of backlight module 41 more can comprise a converting unit (not shown), for example be a DC-DC rectifier (DC-DC converter), wherein, converting unit can electrically connect with pwm unit 4131 and light emitting diode 411 respectively, with pulse-width signal P2 ' corresponding conversion that pwm unit 4131 is produced is a drive current, and perhaps driving voltage is with driven for emitting lights diode 411.
Again, light emitting diode 411 can be a red light-emitting diode, a green light LED or a blue light-emitting diode.Relatively, photodetector 412 can be a ruddiness detecting element, a green glow detecting element or a blue light detecting element, to detect the light that light emitting diode 411 is sent.In addition, signal value S1 ' can be a magnitude of voltage or the current value power with the corresponding photodetector 412 light L1 ' that detected.
Hold, because of backlight module of the present invention is with the dutycycle correction of generation pulse-width signal and is maintained at greater than 75% (be higher than known 50%), under the arithmetic capability of pwm unit, still can regulate and control light colourity or briliancy more accurately so that backlight module of the present invention can be upgraded.
First embodiment of liquid crystal indicator
Please refer to shown in Figure 13ly, comprise a backlight module 31 and a display panels 32 according to the liquid crystal indicator 3 of first embodiment of the invention.Backlight module 31 has at least one light emitting diode 311, a photodetector 312, a pwm unit 3132, a comparing unit 3131 and a judging unit 3133.Wherein, the backlight module 31 of present embodiment describes in detail in the backlight module of first embodiment of the invention, does not give unnecessary details at this.
Light L2, L4 that light emitting diode 311 is sent (not showing among Figure 13) or light L3 provide display panels 32 to show required light source.
Hold, because of liquid crystal indicator of the present invention with the dutycycle correction of generation pulse-width signal and be maintained at greater than 75% (be higher than known 50%), so that backlight module of the present invention can be regulated and control light colourity or briliancy more accurately under the arithmetic capability of pwm unit of needn't upgrading.
Second embodiment of liquid crystal indicator
Please refer to shown in Figure 14ly, comprise a backlight module 41 and a display panels 42 according to the liquid crystal indicator 4 of second embodiment of the invention.Backlight module 41 has at least one light emitting diode 411, a photodetector 412, a pwm unit 4131 and a comparing unit 4132.Wherein, the backlight module 41 of present embodiment describes in detail in the backlight module of second embodiment of the invention, does not give unnecessary details at this.
The light L2 ' that light emitting diode 411 is sent provides display panels 42 to show required light source.
Hold, because of liquid crystal indicator of the present invention with the dutycycle correction of generation pulse-width signal and be maintained at greater than 75% (be higher than known 50%), so that backlight module of the present invention can be regulated and control light colourity or briliancy more accurately under the arithmetic capability of pwm unit of needn't upgrading.
From the above, driving method, backlight module and liquid crystal indicator according to backlight module of the present invention, because of pwm unit can be with the dutycycle correction of generation pulse-width signal and be maintained at greater than 75% (be higher than known 50%), so that the driving method of backlight module of the present invention, backlight module and liquid crystal indicator, can under the arithmetic capability of pwm unit of needn't upgrading, regulate and control light colourity or briliancy more accurately.
The above only is an illustrative, but not is restricted.Anyly do not break away from spirit of the present invention and scope, and it is carried out equivalent modifications or change, all should be included in the claim restricted portion.
Claims (18)
1. the driving method of a backlight module, this backlight module has pwm unit and at least one light emitting diode, and this light emitting diode is driven according to first pulse-width signal of one first dutycycle correspondence, and the driving method of this backlight module comprises:
Detect light that this light emitting diode sends to produce signal value;
Relatively this signal value and desired value are to produce comparative result;
Adjust this first dutycycle to the second dutycycle according to this comparative result; And
Produce one second pulse-width signal to drive this light emitting diode by this pwm unit according to this second dutycycle, wherein this second dutycycle is in fact greater than 75% and less than 100%.
2. the driving method of backlight module as claimed in claim 1, wherein producing one second pulse-width signal by this pwm unit according to this second dutycycle with the step that drives this light emitting diode is, by this pwm unit according to this second duty when a current level produce this second pulse-width signal to drive this light emitting diode.
3. the driving method of backlight module as claimed in claim 1, wherein this second dutycycle is in fact greater than 75% and less than 95%.
4. backlight module comprises:
At least one light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence;
One photodetector detects light that this light emitting diode sends to produce signal value;
One comparing unit, relatively this signal value and desired value are to produce comparative result; And
One pwm unit, adjust this first dutycycle to the second dutycycle according to this comparative result, and produce one second pulse-width signal to drive this light emitting diode according to this second dutycycle, wherein this second dutycycle is in fact greater than 75% and less than 100%.
5. backlight module as claimed in claim 4, wherein this pwm unit according to this second duty when a current level produce one second pulse-width signal to drive this light emitting diode.
6. backlight module as claimed in claim 4, wherein this second dutycycle is in fact greater than 75% and less than 95%.
7. liquid crystal indicator comprises:
One backlight module has:
At least one light emitting diode is used for being driven according to one first pulse-width signal of the first dutycycle correspondence;
One photodetector detects light that this light emitting diode sends to produce signal value;
One comparing unit, relatively this signal value and desired value are to produce a comparative result; And
One pwm unit, be used for adjusting this first dutycycle to the second dutycycle according to this comparative result, and produce one second pulse-width signal to drive this light emitting diode according to this second dutycycle, wherein this second dutycycle is in fact greater than 75% and less than 100%; And
One display panels, wherein the light that this light emitting diode sent provides this display panels to show required light source.
8. liquid crystal indicator as claimed in claim 7, wherein this pwm unit according to this second duty when a current level produce one second pulse-width signal to drive this light emitting diode.
9. liquid crystal indicator as claimed in claim 7, wherein this second dutycycle is in fact greater than 75% and less than 95%.
10. the driving method of a backlight module, this backlight module has pwm unit and at least one light emitting diode, and this light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence, and the driving method of this backlight module comprises:
Detect light that this light emitting diode sends to produce signal value;
Relatively this signal value and desired value are to produce comparative result;
Adjust this first dutycycle to the second dutycycle according to this comparative result; And
Judge this second dutycycle, wherein if this second dutycycle greater than 75% and less than 100% o'clock, produce second pulse-width signal to drive this light emitting diode by this pwm unit according to this second dutycycle, if this second dutycycle was less than 75% o'clock, adjust this second dutycycle to the, three dutycycles by this pwm unit, and the 3rd dutycycle is greater than 75% and less than 100%, and produces the 3rd pulse-width signal to drive this light emitting diode by this pwm unit according to the 3rd dutycycle.
11. the driving method of backlight module as claimed in claim 10, wherein judge in the step of this second dutycycle, if this second dutycycle is greater than 75% and less than 100% o'clock, by this pwm unit according to this second duty when one first current level produce this second pulse-width signal to drive this light emitting diode, if this second dutycycle was less than 75% o'clock, adjust this second dutycycle to the 3rd dutycycle by this pwm unit, and adjust this first current level to, second current level, by this pwm unit according to the 3rd duty when this second current level produce the 3rd pulse-width signal to drive this light emitting diode, wherein the 3rd dutycycle is greater than 75% and less than 100%, and this first current level is greater than this second current level.
12. the driving method of backlight module as claimed in claim 11, wherein the product of this second current level and the 3rd dutycycle equals the product of this first current level and this second dutycycle in fact.
13. a backlight module comprises:
At least one light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence;
One photodetector detects light that this light emitting diode sends to produce signal value;
One comparing unit, relatively this signal value and desired value are to produce a comparative result;
One pwm unit is used for adjusting this first dutycycle to the second dutycycle according to this comparative result; And
One judging unit, judge this second dutycycle, wherein if this second dutycycle greater than 75% and less than 100% o'clock, this pwm unit produces second pulse-width signal to drive this light emitting diode according to this second dutycycle, if this second dutycycle was less than 75% o'clock, this pwm unit is adjusted this second dutycycle to the, three dutycycles, and the 3rd dutycycle is greater than 75% and less than 100%, and this pwm unit produces the 3rd pulse-width signal to drive this light emitting diode according to the 3rd dutycycle.
14. backlight module as claimed in claim 13, this second dutycycle of this judgment unit judges wherein, if this second dutycycle is greater than 75% and less than 100% o'clock, this pwm unit according to this second duty when one first current level produce this second pulse-width signal to drive this light emitting diode, if this second dutycycle was less than 75% o'clock, this pwm unit is adjusted this second dutycycle to the 3rd dutycycle, and adjust this first current level to, second current level, this pwm unit according to the 3rd duty when this second current level produce the 3rd pulse-width signal to drive this light emitting diode, wherein the 3rd dutycycle is greater than 75% and less than 100%, and this first current level is greater than this second current level.
15. backlight module as claimed in claim 14, wherein the product of this second current level and the 3rd dutycycle equals the product of this first current level and this second dutycycle in fact.
16. a liquid crystal indicator comprises:
One backlight module has:
At least one light emitting diode is driven according to first pulse-width signal of the first dutycycle correspondence;
One photodetector detects light that this light emitting diode sends to produce signal value;
One comparing unit, relatively this signal value and desired value are to produce a comparative result;
One pwm unit is adjusted this first dutycycle to the second dutycycle according to this comparative result; And
One judging unit, judge this second dutycycle, if this second dutycycle is greater than 75% and less than 100% o'clock, this pwm unit produces second pulse-width signal to drive this light emitting diode according to this second dutycycle, if this second dutycycle was less than 75% o'clock, this pwm unit is adjusted this second dutycycle to the 3rd dutycycle, and the 3rd dutycycle is greater than 75% and less than 100%, and this pwm unit produces one the 3rd pulse-width signal to drive this light emitting diode according to the 3rd dutycycle; And
One display panels, wherein the light that light emitting diode sent provides this display panels to show required light source.
17. liquid crystal indicator as claimed in claim 16, this second dutycycle of this judgment unit judges wherein, if this second dutycycle is greater than 75% and less than 100% o'clock, this pwm unit according to this second duty when one first current level produce this second pulse-width signal to drive this light emitting diode, if this second dutycycle was less than 75% o'clock, this pwm unit is adjusted this second dutycycle to the 3rd dutycycle, and adjust this first current level to, second current level, this pwm unit according to the 3rd duty when this second current level produce the 3rd pulse-width signal to drive this light emitting diode, wherein the 3rd dutycycle is greater than 75% and less than 100%, and this first current level is greater than this second current level.
18. liquid crystal indicator as claimed in claim 17, wherein the product of this second current level and the 3rd dutycycle equals the product of this first current level and this second dutycycle in fact.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2007100857734A CN101266345B (en) | 2007-03-14 | 2007-03-14 | Backlight module and its drive method and LCD device |
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| CN2007100857734A CN101266345B (en) | 2007-03-14 | 2007-03-14 | Backlight module and its drive method and LCD device |
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| CN101266345B true CN101266345B (en) | 2011-04-20 |
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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 |
| CN105096843A (en) * | 2015-08-19 | 2015-11-25 | 京东方科技集团股份有限公司 | Backlight source, adjustment method and adjustment device thereof and display device |
| CN107146582B (en) * | 2017-06-14 | 2019-09-13 | 昆山龙腾光电有限公司 | Backlight driver and its driving method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1428758A (en) * | 2001-11-14 | 2003-07-09 | 松下电器产业株式会社 | Drive circuit and drive method, back light, liquid crystal display device for piezoelectric transformer |
| CN1547062A (en) * | 1997-10-16 | 2004-11-17 | Nec������ʽ���� | Cold-cathode tube lighting circuit with protection circuit for piezoelectric transformer |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1547062A (en) * | 1997-10-16 | 2004-11-17 | Nec������ʽ���� | Cold-cathode tube lighting circuit with protection circuit for piezoelectric transformer |
| CN1428758A (en) * | 2001-11-14 | 2003-07-09 | 松下电器产业株式会社 | Drive circuit and drive method, back light, liquid crystal display device for piezoelectric transformer |
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