CN101311782A - Gray scale voltage generation circuit and its operation method - Google Patents
Gray scale voltage generation circuit and its operation method Download PDFInfo
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- CN101311782A CN101311782A CNA2007101042976A CN200710104297A CN101311782A CN 101311782 A CN101311782 A CN 101311782A CN A2007101042976 A CNA2007101042976 A CN A2007101042976A CN 200710104297 A CN200710104297 A CN 200710104297A CN 101311782 A CN101311782 A CN 101311782A
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Abstract
A gray scale voltage-generating circuit can receive pixel data and can generate a first gray scale voltage during a first period according to a first reference voltage, thus leading a display to show a plurality of different gray scales according to the pixel data. The gray scale voltage-generating circuit can generate a second gray scale voltage during a second period according to a second reference voltage, thus causing the display to show a common gray scale. The first reference voltage is different from the second reference voltage.
Description
Technical field
The present invention relates to a kind of GTG (Gray Scale) voltage generation circuit, particularly relate to a kind of gray scale voltage generation circuit that is applicable to flat-panel screens.
Background technology
There is many flat-panel screens (Flat Panel Display) technology to be developed in succession in recent years, wherein, LCD (LCD) because have that high image quality, volume are little, in light weight, advantages such as low voltage drive, low power consumption and applied range, therefore be widely used in medium and small Portable TV, mobile phone, shoot with video-corder consumer electronics or computer products such as projector, mobile computer, desktop display and projection TV, and replace cathode-ray tube (CRT) (Cathode Radiation Tube gradually; CRT), become the main flow of following display, wherein thin film transistor (TFT) (Thin Film Transistor particularly; TFT) LCD because of the characteristic of its high display quality and low consumpting power, has almost occupied most market.
Thin Film Transistor-LCD is by applying the pixel of a suitable gray scale voltage on panel, uses the angle that changes the pixel liquid crystal molecule, and then changes the transmittance of panel, and reaches the GTG that institute's desire shows.Yet, because of the video picture mode of LCD is a freeze mode (Hold-type) video picture mode, different with pulsed (Impulse-type) the video picture mode of traditional cathode-ray tube display, therefore, when the video picture mode of using freeze mode shows a dynamic image, will produce smear (Blurring) phenomenon to the human visual system.Known solution is the Push And Release with the switching backlight module at present, or by the black picture signal of system end input, to insert the method for black picture, solves above-mentioned problem.Yet it is more high-power that the Push And Release that constantly switches backlight module will cause backlight module to expend, and if specially send the signal of black picture by system end, need extra controlling signal, thus, will increase the complexity of system end line design.
In addition, in the moment of LCD start (Turn On), the data signals that this moment is correct for example can be low voltage difference signal (Low Voltage Differential Signal; LVDS), do not input to data drive circuit (Data Driver) as yet, but this moment, data drive circuit can be because of last time showing or other factors, make its inside have remaining data current potential, be called original state (Initial State), existing side by side is about to this residual data current potential output, moreover different data driver (Driving IC) can be exported different signals according to its different original state.Although this moment, fluorescent tube was not lighted as yet, but still indistinctly can on picture, see banded noise.
Summary of the invention
Therefore, the purpose of this invention is to provide a kind of gray scale voltage generation circuit, need not switch the Push And Release of backlight module, promptly exportable black picture.
Another object of the present invention is that a kind of gray scale voltage generation circuit is being provided, switch in the gray scale voltage generation circuit is arranged in the data driver, and by these switches of control, make the black picture of display output, the banded noise that on display picture, produces when avoiding system's power supply.
Another purpose of the present invention is that a kind of gray scale voltage generation circuit is being provided, and switch set in the gray scale voltage generation circuit can directly be formed by data driver technology, so can save the cost of part.
A further object of the present invention is that a kind of gray scale voltage generation circuit is being provided, and switch directly is arranged in the data driver, so be easier to reach high-frequency operation.
According to above-mentioned purpose of the present invention, a kind of device is proposed, at least comprise a gray scale voltage generation circuit, can receive a pixel data, and can be in the cycle very first time, according to one first group of reference voltage, produce one first group of gray scale voltage, with according to this pixel data, make a display show a plurality of different shade of gray, and can be in one second time cycle, according to one second group of reference voltage, produce one second group of gray scale voltage, so that this display shows a common shade of gray, wherein second group of reference voltage of this first group of reference voltage and this is different.
According to embodiments of the invention, above-mentioned common shade of gray comprises a black picture at least.
According to another object of the present invention, a kind of gray scale voltage generation circuit is proposed, be arranged in a data driver.Above-mentioned gray scale voltage generation circuit comprises one first digital/analog converter and one first on-off circuit at least.First digital/analog converter is in order to export one first group of gray scale voltage.First on-off circuit comprises one first switch, a second switch and a first input end at least.First switch is electrically connected first digital/analog converter, and second switch is electrically connected first input end, and the second switch and first switch inverse.First input end can be imported one first reference voltage.
In the cycle very first time, first switch conduction, not conducting of second switch, then first digital/analog converter is exported first group of gray scale voltage, so that a display shows a plurality of different shade of gray, and in one second time cycle, the first not conducting of switch, first reference voltage is then exported in the second switch conducting, so that display shows a common shade of gray.
According to one embodiment of the invention, comprise at least that also a selector switch and first input end are electrically connected, to select first reference voltage from a plurality of reference voltage sources.According to one embodiment of the invention, also comprise a sequential control circuit at least, with a controlling signal of the above-mentioned switch of output control.
According to another purpose of the present invention, a kind of gray scale voltage generation circuit is proposed, comprise resistance string and one second interior resistance string in one first voltage end, one second voltage end, a plurality of bleeder circuit, a plurality of switch, one first at least.First voltage end is in order to import one first reference voltage, and second voltage end is in order to import one second reference voltage.A plurality of bleeder circuits are electrically connected between first voltage end and second voltage end, in order to produce a plurality of dividing potential drops.A plurality of switches, wherein an end of each switch is electrical connected with bleeder circuit partly respectively.Resistance string is electrically connected the maximum of these dividing potential drops and the other end of part switch in first, and the first interior resistance string can be further divided into these dividing potential drops of part one first group of gray scale voltage output.Resistance string is electrically connected the reckling of these dividing potential drops and the other end of rest switch in second, and the second interior resistance string can be further divided into all the other these dividing potential drops one second group of gray scale voltage output.
In the cycle very first time, these switch conductions, gray scale voltage generation circuit is exported first group of gray scale voltage and second group of gray scale voltage by resistance string in the first interior resistance string and second, so that a display shows a plurality of different shade of gray.And in one second time cycle, these not conductings of switch, gray scale voltage generation circuit is exported the maximum of these dividing potential drops and the reckling of these dividing potential drops by resistance string in the first interior resistance string and second, so that display shows a common shade of gray.
According to one embodiment of the invention, also comprise a sequential control circuit at least, with a controlling signal of these switches of output control.Above-mentioned switch is N type metal oxide semiconductor transistor (NMOS) or P-type mos transistor (PMOS), and this display is the stable twisted nematic LCD.
According to a further object of the present invention, propose a kind of gray scale voltage generation circuit, comprise resistance string in one first voltage end, one second voltage end, a plurality of bleeder circuit, a plurality of first switch, one first, one second interior resistance string, a second switch, one the 3rd switch, a tertiary voltage end and one the 4th voltage end at least.First voltage end is in order to import one first reference voltage, and second voltage end is in order to import one second reference voltage.A plurality of bleeder circuits are electrically connected between first voltage end and second voltage end, in order to produce a plurality of dividing potential drops.A plurality of first switches, wherein an end of each first switch is electrically connected with first voltage end and each these bleeder circuit respectively.Resistance string is electrically connected the other end of first these first switches of part in first, and the first interior resistance string can be further divided into these dividing potential drops of part one first group of gray scale voltage output.Resistance string is electrically connected the other end of all the other these first switches in second, and the second interior resistance string can be further divided into all the other these dividing potential drops one second group of gray scale voltage output.Second switch be electrically connected on these first switches one of them and first between the resistance string, second switch and these first switch inverse.The 3rd switch be electrically connected on these first switches wherein another and second between the resistance string, the 3rd switch and these first switch inverse.Tertiary voltage end and second switch are electrical connected, and the tertiary voltage end is in order to import one the 3rd reference voltage.The 4th voltage end and the 3rd switch are electrical connected, and the 4th voltage end is in order to import one the 4th reference voltage.
In the cycle very first time, these first switch conductions, second switch and the 3rd not conducting of switch, gray scale voltage generation circuit is exported first group of gray scale voltage and second group of gray scale voltage by resistance string in the first interior resistance string and second, so that a display shows a plurality of different shade of gray.And in one second time cycle, these not conductings of first switch, second switch and the 3rd switch conduction, gray scale voltage generation circuit is exported the 3rd reference voltage and the 4th reference voltage by resistance string in the first interior resistance string and second, so that display shows a common shade of gray.
According to one embodiment of the invention, when display was vertical alignment type liquid crystal display device, the 3rd reference voltage and the 4th reference voltage equaled V
COMVoltage.When display was the stable twisted nematic LCD, the 3rd reference voltage equaled the maximum of first group of gray scale voltage, and the 4th reference voltage equals the reckling of second group of gray scale voltage.According to one embodiment of the invention, also comprise a control circuit at least, a controlling signal of exportable these switches of control.
According to a purpose more again of the present invention, a kind of method of operating of gray scale voltage generation circuit is proposed, comprise at least: control a plurality of reference voltages and produce a plurality of gray scale voltages, to control the shown GTG of a plurality of pixels of a display.The step of above-mentioned these reference voltages of control comprises at least: in the cycle very first time, set these reference voltages to different values, so that these pixels according to pixel data, show different shade of gray; And in one second time cycle, set these reference voltages to one or more values, so that these pixels show a common shade of gray, this common shade of gray and pixel data are irrelevant.
According to one embodiment of the invention, wherein the step of these these reference voltages of control comprises a plurality of switches of control at least, to determine the setting value of these reference voltages.
Description of drawings
For above and other objects of the present invention, feature and advantage can be become apparent,, and be described with reference to the accompanying drawings as follows especially exemplified by a preferred embodiment:
Fig. 1 shows the gray scale voltage generation circuit synoptic diagram according to first embodiment of the invention.
Fig. 2 shows the gray scale voltage generation circuit synoptic diagram according to second embodiment of the invention.
Fig. 3 shows the gray scale voltage generation circuit synoptic diagram according to third embodiment of the invention.
Fig. 4 shows the gray scale voltage generation circuit synoptic diagram according to fourth embodiment of the invention.
Fig. 5 shows the sequential control synoptic diagram that produces black picture according to the gray scale voltage generation circuit of present embodiment.
The reference numeral explanation
102: digital/analog converter 104: on-off circuit
106: output buffer
202: the first digital/analog converters
206: the first output buffers of 204: the first on-off circuits
208: the second digital/analog converters
210: 212: the second output buffers of second switch circuit
214: multiplexer 302: input end
304: earth terminal 306: bleeder circuit
310: the second interior resistance string of resistance string in 308: the first
402: input end 404: earth terminal
406: 408: the first interior resistance string of bleeder circuit
504: the controlling signal 506 of electronegative potential: the controlling signal of noble potential
508: the controlling signal 510 of electronegative potential: the controlling signal of noble potential
Embodiment
The present invention discloses a kind of gray scale voltage generation circuit, by the switch in the control gray scale voltage generation circuit, make the simulation gray scale voltage or a common voltage of gray scale voltage generation circuit image output, this common voltage can make display show a common shade of gray, for example can be a black picture.Black picture can be shown between the normal images picture, with the smear phenomenon of minimizing dynamic image, or is shown in before the system initialization, makes display when initial start, can demonstrate uniform black image, with the banded noise of resolution system power supply moment generation.In order to make narration of the present invention more detailed and complete, can describe with reference to the following example and in conjunction with Fig. 1 to Fig. 5.
First embodiment:
Please refer to Fig. 1, Fig. 1 is the gray scale voltage generation circuit synoptic diagram according to first embodiment of the invention.The gray scale voltage generation circuit of present embodiment is arranged in data driver, comprises a digital/analog converter 102, an on-off circuit 104 and an output buffer 106 at least.On-off circuit 104 comprises a switch Q1, a switch Q2 and an input end Vx at least, wherein, and switch Q1 and switch Q2 anti-phase (promptly two switches are not the state of conducting simultaneously).Switch Q1 and switch Q2 for example can be used as the assembly of switch for N type metal oxide semiconductor transistor (NMOS), P-type mos transistor (PMOS) or other.Input end Vx can import arbitrary magnitude of voltage, for example can be GMA 1, GMA 10, V
COM....The gray scale voltage generation circuit of present embodiment also comprises a sequential control circuit (not shown) at least, can produce gauge tap Q1 and the required controlling signal of switch Q2.In addition, in other embodiments of the invention, can comprise that also a selector switch and input end Vx are electrically connected, from a plurality of reference voltage sources, to select an input voltage.
In the present embodiment, gray scale voltage generation circuit can utilize controlling signal to come the Push And Release of gauge tap Q1 and switch Q2, make simulation gray scale voltage that output buffer 106 output digital/analog converters 102 are transmitted or the magnitude of voltage of input end Vx, and then make display show normal images or black picture.With vertical orientation (VA) type LCD is example, when controlling signal is noble potential (High), switch Q1 conducting, not conducting of switch Q2, then output buffer 106 can be exported the simulation gray scale voltage that digital/analog converter 102 is transmitted, make display show a plurality of different shade of gray, that is display show the normal images picture.And when controlling signal is electronegative potential (Low), not conducting of switch Q1, switch Q2 conducting, the magnitude of voltage of importing because of input end Vx is V
COM, output buffer 106 can output V
COMMagnitude of voltage makes display show a common shade of gray, and for example display shows a black picture.In other embodiments of the invention, other value is imported in the also visual practical application of input end Vx, makes display show black picture.
Second embodiment:
Please refer to Fig. 2, Fig. 2 is the gray scale voltage generation circuit synoptic diagram according to second embodiment of the invention.Present embodiment is particularly useful for twisted nematic (TN) type LCD.The gray scale voltage generation circuit of present embodiment is arranged in data driver, comprises one first digital/analog converter 202, one first on-off circuit 204, one first output buffer 206, one second digital/analog converter 208, a second switch circuit 210, one second output buffer 212 and a multiplexer 214 at least.First on-off circuit 204 comprises a switch Q1, a switch Q2 and a first input end Vx at least
1, wherein, switch Q1 and switch Q2 are anti-phase.Second switch circuit 210 comprises a switch Q3, a switch Q4 and one second input end Vx at least
2, wherein, switch Q3 and switch Q4 are anti-phase.Above-mentioned switch for example can be used as the assembly of switch for N type metal oxide semiconductor transistor, P-type mos transistor or other.The gray scale voltage generation circuit of present embodiment also comprises a sequential control circuit (not shown) at least, can produce gauge tap Q1, switch Q2, switch Q3 and the required controlling signal of switch Q4.
In the present embodiment, gray scale voltage generation circuit can utilize controlling signal to come the Push And Release of gauge tap Q1, switch Q2, switch Q3 and switch Q4, makes first output buffer 206 and second output buffer 212 export the simulation gray scale voltage that first digital/analog converter 202 and second digital/analog converter 208 transmitted respectively or exports first input end Vx respectively
1With the second input end Vx
2Magnitude of voltage, and then make display show normal images or black picture.
With the stable twisted nematic LCD is example, in the present embodiment, when controlling signal is noble potential, switch Q1 and switch Q3 conducting, switch Q2 and not conducting of switch Q4, then first output buffer 206 can be simulated gray scale voltage via first group that multiplexer 214 outputs first digital/analog converter 202 is transmitted, second output buffer 212 can be simulated gray scale voltage via second group that multiplexer 214 outputs second digital/analog converter 208 is transmitted, make display show a plurality of different shade of gray, that is display show the normal images picture.And when controlling signal was electronegative potential, switch Q1 and not conducting of switch Q3, and switch Q2 and switch Q4 conducting were because of first input end Vx
1The magnitude of voltage of input is the GMA 1 and the second input end Vx
2The magnitude of voltage of input is GMA 10, then first output buffer 206 can be via multiplexer 214 output GMA 1 magnitude of voltage, second output buffer 212 can make display show a common shade of gray via multiplexer 214 output GMA 10 magnitudes of voltage, and for example display shows a black picture.
In addition, because present embodiment uses the stable twisted nematic LCD, and the stable twisted nematic LCD needs periodically liquid crystal to be reversed, so present embodiment can utilize multiplexer 214 to change to be sent to the signal polarity of first output buffer 206 and second output buffer 212, thus, first output buffer 206 and second output buffer 212 be output cathode signal and negative polarity signal periodically just, so can reduce the quantity of output buffer, reduce circuit complexity.In the present embodiment, multiplexer 214 makes first output buffer 206 and second output buffer 212 alternately export first group of simulation gray scale voltage/GMA 1 magnitude of voltage and second group of simulation gray scale voltage/GMA 10 magnitude of voltage according to another controlling signal.For example, suppose that first group of simulation gray scale voltage is the positive polarity gray scale voltage, and second group of simulation gray scale voltage is the negative polarity gray scale voltage, and utilize a POL controlling signal to control the output of multiplexer 214, then when the POL controlling signal is noble potential, first output buffer, 206 output first group of gray scale voltage (positive polarity), second output buffer, 212 output second group of gray scale voltage (negative polarity).And when the POL controlling signal is electronegative potential, first output buffer, 206 output second group of gray scale voltage (negative polarity), second output buffer, 212 output first group of gray scale voltage (positive polarity).Perhaps, when the POL controlling signal is noble potential, first output buffer, 206 output GMA, 1 magnitude of voltage, second output buffer, 212 output GMA, 10 magnitudes of voltage.And when the POL controlling signal is electronegative potential, first output buffer, 206 output GMA, 10 magnitudes of voltage, second output buffer, 212 output GMA, 1 magnitude of voltage.Positive polarity signal and negative polarity signal are by first output buffer 206 and the second alternately output of output buffer 212, and liquid crystal just can periodically reverse.
The 3rd embodiment:
Please refer to Fig. 3, Fig. 3 is the gray scale voltage generation circuit synoptic diagram according to third embodiment of the invention.Present embodiment is applicable to the stable twisted nematic LCD.The gray scale voltage generation circuit of present embodiment comprises resistance string 308 and one second interior resistance string 310 in an input end 302, an earth terminal 304, bleeder circuit 306, a plurality of switch (switch Q1 is to switch Q8), one first at least.Input end 302 is in order to import a reference voltage (V
REF); Earth terminal 304 is in order to import a ground voltage; Bleeder circuit 306 is electrically connected between input end 302 and the earth terminal 304, and bleeder circuit 306 comprises 10 resistance, and (R1～R10) is in order to minute to extrude 10 gray scale voltages (GMA1～GMA 10); By controlling signal control conducting whether switch Q1 is electrical connected with bleeder circuit 306 respectively to switch Q8, can make above-mentioned gray scale voltage (GMA 1～GMA 10) of gray scale voltage generation circuit output or fixed voltage (GMA 1 and GMA 10).Resistance string 308 is electrically connected input end 302 and part bleeder circuit in first, resistance string 310 is electrically connected between remaining bleeder circuit in second, in first in the resistance string 308 and second resistance string 310 can be one first group of gray scale voltage (V0～V63) and one second group of gray scale voltage (V ' 0～V ' 63) with 10 further dividing potential drops of gray scale voltage, as shown in Figure 3.Above-mentioned switch for example can be used as the assembly of switch for N type metal oxide semiconductor transistor, P-type mos transistor or other.The gray scale voltage generation circuit of present embodiment also comprises a sequential control circuit (not shown) at least, can produce gauge tap Q1 to the required controlling signal of switch Q8.
In the present embodiment, gray scale voltage generation circuit can utilize controlling signal come gauge tap Q1 to the conducting of switch Q8 whether, exporting magnitude of voltage to a digital/analog converter of first group of gray scale voltage and second group of gray scale voltage or output GMA 1 and GMA10, and then make display show normal images or black picture.
In the present embodiment, when controlling signal is noble potential, switch Q1 is to switch Q8 conducting, then bleeder circuit 306 normal operations, reference voltage dividing potential drop with input, (GMA 1～GMA10) to produce 10 gray scale voltages, again through resistance string 310 dividing potential drops in the first interior resistance string 308 and second, make gray scale voltage generation circuit export first group of gray scale voltage (V0～V63) and second group of gray scale voltage (V ' 0～V ' 63) to digital/analog converter, and then make display show a plurality of different shade of gray, that is display shows the normal images picture.And when controlling signal is electronegative potential, switch Q1 is to not conducting of switch Q8, then resistance string 310 is a floating in the first interior resistance string 308 and second, gray scale voltage generation circuit output GMA 1 magnitude of voltage (V0～V63 all equals GMA 1) and GMA 10 magnitudes of voltage (V ' 0～V ' 63 all equal GMA 10) are to digital/analog converter, make the positive polarity output buffer in the data driver all export GMA 1 magnitude of voltage, and make the negative polarity output buffer all export GMA 10 magnitudes of voltage, and then make display show a common shade of gray, for example display shows a black picture.
The 4th embodiment:
Then, please refer to Fig. 4, Fig. 4 is the gray scale voltage generation circuit synoptic diagram according to fourth embodiment of the invention.The gray scale voltage generation circuit of present embodiment comprises resistance string 408, one second interior resistance string 410, a first input end Vx in an input end 402, an earth terminal 404, bleeder circuit 406, a plurality of switch (switch Q1 is to switch Q10), one first at least
1, one second input end Vx
2, a switch Q11 and a switch Q12, wherein, switch Q1 is anti-phase to switch Q10 and switch Q11, switch Q11 and switch Q12 homophase.Input end 402 is in order to import a reference voltage (V
REF); Earth terminal 404 is in order to import a ground voltage; Bleeder circuit 406 is electrically connected between input end 402 and the earth terminal 404, and bleeder circuit 406 comprises 10 resistance, and (R1～R10) is in order to minute to extrude 10 gray scale voltages (GMA 1～GMA 10); Switch Q1 is electrical connected with input end 402 and bleeder circuit 406 respectively to the end of switch Q10.Resistance string 408 is electrically connected the other end of switch Q1 to switch Q5 in first, resistance string 410 is electrically connected the other end of switch Q6 to switch Q10 in second, in first in the resistance string 408 and second resistance string 410 can be one first group of gray scale voltage (V0～V63) and one second group of gray scale voltage (V ' 0～V ' 63) with 10 further dividing potential drops of gray scale voltage, as shown in Figure 4.
Switch Q11 is electrically connected between the switch Q1 and the first interior resistance string 408, and switch Q11 is electrically connected first input end Vx
1, switch Q12 is electrically connected between the switch Q10 and the second interior resistance string 410, and switch Q12 is electrically connected the second input end Vx
2By controlling signal control conducting whether switch Q1 can make the above-mentioned gray scale voltage of gray scale voltage generation circuit output (GMA 1～GMA10) or output first input end Vx to switch Q10, switch Q11 and switch Q12
1With the second input end Vx
2Magnitude of voltage.Above-mentioned switch for example can be used as the assembly of switch for N type metal oxide semiconductor transistor, P-type mos transistor or other.The gray scale voltage generation circuit of present embodiment also comprises a sequential control circuit (not shown) at least, can produce gauge tap Q1 to switch Q10, switch Q11 and the required controlling signal of switch Q12.
In the present embodiment, gray scale voltage generation circuit can utilize controlling signal come gauge tap Q1 to the conducting of switch Q10, switch Q11 and switch Q12 whether, to export first group of gray scale voltage and second group of gray scale voltage or output first input end Vx
1With the second input end Vx
2Magnitude of voltage to a digital/analog converter, and then make display show normal images or black picture.
With the vertical alignment type liquid crystal display device is example, when controlling signal is noble potential, switch Q1 is to switch Q10 conducting, switch Q11 and not conducting of switch Q12, then bleeder circuit 406 normal operations, reference voltage dividing potential drop with input, to produce 10 gray scale voltages (GMA 1～GMA 10), again through resistance string 410 dividing potential drops in the first interior resistance string 408 and second, make gray scale voltage generation circuit export first group of gray scale voltage (V0～V63) and second group of gray scale voltage (V ' 0～V ' 63) to digital/analog converter, and then make display show a plurality of different shade of gray, that is display shows the normal images picture.And when controlling signal was electronegative potential, switch Q1 was to not conducting of switch Q10, and switch Q11 and switch Q12 conducting, then resistance string 410 is a floating in the first interior resistance string 408 and second, because of first input end Vx
1With the second input end Vx
2The magnitude of voltage of input is all V
COM, then V0～V63 and V ' 0～V ' 63 all equal V
COMMagnitude of voltage, gray scale voltage generation circuit just can be exported V
COMMagnitude of voltage makes the output buffer output V in the data driver to digital/analog converter
COMMagnitude of voltage, and then make display show a common shade of gray, for example display shows a black picture.
Then, be example with the stable twisted nematic LCD again, when controlling signal is noble potential, switch Q1 is to switch Q10 conducting, switch Q11 and not conducting of switch Q12, then bleeder circuit 406 normal operations, reference voltage dividing potential drop with input, to produce 10 gray scale voltages (GMA 1～GMA 10), again through resistance string 410 dividing potential drops in the first interior resistance string 408 and second, make gray scale voltage generation circuit export first group of gray scale voltage (V0～V63) and second group of gray scale voltage (V ' 0～V ' 63) to digital/analog converter, and then make display show a plurality of different shade of gray, that is display shows the normal images picture.And when controlling signal was electronegative potential, switch Q1 was to not conducting of switch Q10, and switch Q11 and switch Q12 conducting, then resistance string 410 is all floating in the first interior resistance string 408 and second, because of first input end Vx
1The magnitude of voltage of input is the GMA 1 and the second input end Vx
2The magnitude of voltage of input is GMA 10, then V0～V63 equals GMA 1 and V ' 0～V ' 63 equals GMA 10, gray scale voltage generation circuit can be exported GMA 1 magnitude of voltage and GMA 10 magnitudes of voltage to digital/analog converter, make the positive polarity output buffer in the data driver all export GMA 1 magnitude of voltage, and make the negative polarity output buffer all export GMA 10 magnitudes of voltage, and then make display show a common shade of gray, for example display shows a black picture.In other embodiments of the invention, first input end Vx
1With the second input end Vx
2The magnitude of voltage of input also can give different magnitudes of voltage according to actual demand, so that display shows black picture.
Then, please refer to Fig. 5, Fig. 5 shows the sequential control synoptic diagram that produces black picture according to the gray scale voltage generation circuit of present embodiment.When sequential control circuit is sent as shown in Figure 5 controlling signal, can reach the effect that black picture inserts.For example; when controlling signal is noble potential (502,506 and 510); switch Q1 is to switch Q10 conducting; switch Q11 and not conducting of switch Q12; then gray scale voltage generation circuit can be exported first group of gray scale voltage (V0～V63) and second group of gray scale voltage (V ' 0～V ' 63); data driver meeting normal operation this moment, display can show normal pictures.And when controlling signal is electronegative potential (504 and 508), switch Q1 is to not conducting of switch Q10, switch Q11 and switch Q12 conducting, and then gray scale voltage generation circuit can be exported first input end Vx
1With the second input end Vx
2Magnitude of voltage, the black picture of liquid crystal display displays one this moment because of quick switching of display cycle can effectively improve the smear phenomenon, promotes the display display quality.
What deserves to be mentioned is, in various embodiments of the present invention, the conducting that only needs to control each switch by controlling signal of sequential control circuit output whether, just the picture of may command display is output as normal pictures or black picture.In addition, each input terminal voltage value also only is an example, and in other embodiments of the invention, each input terminal voltage value also can give different magnitudes of voltage according to actual demand.
By the embodiment of the invention described above as can be known, an advantage of the present invention is, gray scale voltage generation circuit of the present invention can be by the switch in the control gray scale voltage generation circuit, make gray scale voltage generation circuit export a fixed voltage value, so that display produces black picture, can solve the banded noise of Thin Film Transistor-LCD in system's power supply moment generation.
By the embodiment of the invention described above as can be known, another advantage of the present invention is, gray scale voltage generation circuit of the present invention can utilize the switch in the gray scale voltage generation circuit to produce black picture, do not need the system's signal of the black picture of extra input or the Push And Release of switching backlight module, just can solve the smear problem of Thin Film Transistor-LCD.
By the embodiment of the invention described above as can be known, another advantage of the present invention is that switch set in the gray scale voltage generation circuit can directly be formed by data driver technology, so can save the cost of part, and because of switch directly is arranged in the data driver, so be easier to reach high-frequency operation.
Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; those skilled in the art can be used for a variety of modifications and variations under the premise without departing from the spirit and scope of the present invention, so protection scope of the present invention is as the criterion with claim of the present invention.
Claims (12)
1. a display device comprises at least:
One gray scale voltage generation circuit, can receive a pixel data, and can be in the cycle very first time, according to one first group of reference voltage, produce one first group of gray scale voltage, and can produce one second group of gray scale voltage according to one second group of reference voltage, wherein second group of reference voltage of this first group of reference voltage and this is different; And
One liquid crystal panel in the cycle very first time, receives this first group of gray scale voltage with according to a plurality of according to the show different shade of gray of this prime number, in one second time cycle, receives this second group of gray scale voltage to show a common shade of gray.
2. display device as claimed in claim 1, wherein this gray scale voltage generation circuit at least also comprises:
One digital/analog converter is in order to transmit this first group of gray scale voltage; And
One on-off circuit comprises at least:
One first switch is electrically connected this digital/analog converter;
One second switch, this second switch and this first switch inverse; And
One input end is electrically connected this second switch, and this input end can be imported this second group of reference voltage;
Wherein, in this cycle very first time, this first switch conduction, this not conducting of second switch, then this digital/analog converter transmits this first group of gray scale voltage, so that this display shows the shade of gray that these are different, and in this second time cycle, this not conducting of first switch, this second switch conducting, then this gray scale voltage generation circuit is exported this second group of gray scale voltage, so that this display shows this common shade of gray.
3. display device as claimed in claim 1, wherein this gray scale voltage generation circuit at least also comprises:
A plurality of bleeder circuits are electrically connected between one first voltage end and one second voltage end, and these bleeder circuits are in order to produce this first group of reference voltage;
A plurality of switches, wherein an end of each these switch is electrical connected with these bleeder circuits partly respectively;
Resistance string in one first is electrically connected the maximum of this first group of reference voltage and the other end of these switches of part; And
Resistance string in one second is electrically connected a reckling of this first group of reference voltage and the other end of all the other these switches, and this first interior resistance string and this second interior resistance string can be this first group of gray scale voltage output with this first group of reference voltage dividing potential drop;
Wherein, in this cycle very first time, these switch conductions, this gray scale voltage generation circuit is exported this first group of gray scale voltage by this first interior resistance string and this second interior resistance string, so that this display shows the shade of gray that these are different, in this second time cycle, these not conductings of switch, this the maximum and this reckling that this second group of reference voltage is this first group of reference voltage, this gray scale voltage generation circuit is exported this second group of gray scale voltage by this first interior resistance string and this second interior resistance string, so that this display shows this common shade of gray, this maximum and this reckling that this second group of gray scale voltage is this first group of reference voltage.
4. display device as claimed in claim 1, wherein this gray scale voltage generation circuit at least also comprises:
A plurality of bleeder circuits are electrically connected between one first voltage end and one second voltage end, and these bleeder circuits are in order to produce this first group of reference voltage;
A plurality of first switches, wherein an end of each these first switch is electrically connected with this first voltage end and each these bleeder circuit respectively;
Resistance string in one first, electrical connection first is the other end of these first switches partly;
Resistance string in one second is electrically connected the other end of all the other these first switches, this in first resistance string with this in second resistance string can be that this first group of gray scale voltage exported with this first group of reference voltage dividing potential drop;
One second switch is electrically connected in one of them and this first of these first switches between resistance string this second switch and these first switch inverse;
One the 3rd switch, be electrically connected on these first switches wherein another and this in second between the resistance string, the 3rd switch and these first switch inverse;
One first input end is electrical connected with this second switch, in order to input this second group of reference voltage partly; And
One second input end is electrical connected with the 3rd switch, in order to import remaining this second group of reference voltage;
Wherein, in this cycle very first time, these first switch conductions, this second switch and the 3rd not conducting of switch, this gray scale voltage generation circuit is exported this first group of gray scale voltage by this first interior resistance string and this second interior resistance string, so that this display shows the shade of gray that these are different, in this second time cycle, these not conductings of first switch, this second switch and the 3rd switch conduction, this gray scale voltage generation circuit is exported this second group of gray scale voltage by this first interior resistance string and this second interior resistance string, so that this display shows this common shade of gray, this second group of gray scale voltage is this second group of reference voltage.
5. a display device comprises:
One gray scale voltage generation circuit comprises:
One first digital/analog converter is in order to export one first group of gray scale voltage; And
One first on-off circuit comprises at least:
One first switch is electrically connected this first digital/analog converter;
One second switch, this second switch and this first switch inverse; And
One first input end is electrically connected this second switch, and this first input end can be imported one first reference voltage; And
One liquid crystal panel in the cycle very first time, receives this first group of gray scale voltage showing a plurality of different shade of gray, and receives this first reference voltage to show a common shade of gray in one second time cycle;
Wherein, in this cycle very first time, this first switch conduction, this not conducting of second switch, then this first digital/analog converter is exported this first group of gray scale voltage, and in this second time cycle, this not conducting of first switch, this first reference voltage is then exported in this second switch conducting.
6. display device as claimed in claim 5 comprises that at least also a selector switch and this first input end are electrically connected, to select this first reference voltage from a plurality of reference voltage sources.
7. display device as claimed in claim 5 at least also comprises:
One second digital/analog converter is in order to export one second group of gray scale voltage; And
One second switch circuit comprises at least:
One the 3rd switch is electrically connected this second digital/analog converter;
One the 4th switch, the 4th switch and the 3rd switch inverse; And
One second input end is electrically connected the 4th switch, and this second input end can be imported one second reference voltage;
Wherein, in this cycle very first time, the 3rd switch conduction, the 4th not conducting of switch, then this second digital/analog converter is exported this second group of gray scale voltage, and in this second time cycle, the 3rd not conducting of switch, the 4th switch conduction is then exported this second reference voltage, so that this display shows this common shade of gray.
8. display device as claimed in claim 5, at least also comprise that one first output buffer is electrically connected a multiplexer respectively with one second output buffer, this multiplexer can be according to a controlling signal, in this cycle very first time, make this first output buffer and this second output buffer alternately export this first group of gray scale voltage and this second group of gray scale voltage, in this second time cycle, make this first output buffer and this second output buffer alternately export this first reference voltage and this second reference voltage.
9. display device as claimed in claim 8, wherein when this controlling signal is noble potential, this first output buffer is exported this first group of gray scale voltage, this second output buffer is exported this second group of gray scale voltage, and when this controlling signal is electronegative potential, this first output buffer is exported this second group of gray scale voltage, and this second output buffer is exported this first group of gray scale voltage.
10. display device as claimed in claim 8, wherein when this controlling signal is noble potential, this first output buffer is exported this first reference voltage, this second output buffer is exported this second reference voltage, and when this controlling signal is electronegative potential, this first output buffer is exported this second reference voltage, and this second output buffer is exported this first reference voltage.
11. a display device comprises at least:
One gray scale voltage generation circuit comprises:
One first voltage end is in order to import one first reference voltage;
One second voltage end is in order to import one second reference voltage;
A plurality of bleeder circuits are electrically connected between this first voltage end and this second voltage end, in order to produce a plurality of dividing potential drops;
A plurality of switches, wherein an end of each these switch is electrical connected with this bleeder circuit partly respectively;
Resistance string in one first is electrically connected the maximum of these dividing potential drops and the other end of these switches of part, and this first interior resistance string can be further divided into these dividing potential drops of part one first group of gray scale voltage output; And
Resistance string in one second is electrically connected the reckling of these dividing potential drops and the other end of all the other these switches, and this second interior resistance string can be further divided into all the other these dividing potential drops one second group of gray scale voltage output; And
One liquid crystal panel, in the cycle very first time, receive second group of gray scale voltage of this first group of gray scale voltage and this to show a plurality of different shade of gray, in one second time cycle, the reckling of exporting the maximum of these dividing potential drops and these dividing potential drops is to show a common shade of gray;
Wherein, in this cycle very first time, these switch conductions, this gray scale voltage generation circuit is exported this first group of gray scale voltage and this second group of gray scale voltage by this first interior resistance string and this second interior resistance string, in this second time cycle, these not conductings of switch, this gray scale voltage generation circuit is exported the maximum of these dividing potential drops and the reckling of these dividing potential drops by this first interior resistance string and this second interior resistance string.
12. a display device comprises at least:
One gray scale voltage generation circuit comprises:
One first voltage end is in order to import one first reference voltage;
One second voltage end is in order to import one second reference voltage;
A plurality of bleeder circuits are electrically connected between this first voltage end and this second voltage end, in order to produce a plurality of dividing potential drops;
A plurality of first switches, wherein an end of each these first switch is electrically connected with this first voltage end and each these bleeder circuit respectively;
Resistance string in one first, electrical connection first is the other end of these first switches partly, and this first interior resistance string can be further divided into these dividing potential drops of part one first group of gray scale voltage output;
Resistance string in one second is electrically connected the other end of all the other these first switches, this in second resistance string all the other these dividing potential drops can be further divided into one second group of gray scale voltage output;
One second switch is electrically connected in one of them and this first of these first switches between resistance string this second switch and these first switch inverse;
One the 3rd switch, be electrically connected on these first switches wherein another and this in second between the resistance string, the 3rd switch and these first switch inverse;
One tertiary voltage end is electrical connected with this second switch, and this tertiary voltage end is in order to import one the 3rd reference voltage; And
One the 4th voltage end is electrical connected with the 3rd switch, and the 4th voltage end is in order to import one the 4th reference voltage; And
One liquid crystal panel, in the cycle very first time, receive second group of gray scale voltage of this first group of gray scale voltage and this to show a plurality of different shade of gray, in one second time cycle, receive the 3rd reference voltage and the 4th reference voltage to show a common shade of gray;
Wherein, in this cycle very first time, these first switch conductions, this second switch and the 3rd not conducting of switch, this gray scale voltage generation circuit is exported this first group of gray scale voltage and this second group of gray scale voltage by this first interior resistance string and this second interior resistance string, in this second time cycle, these not conductings of first switch, this second switch and the 3rd switch conduction, this gray scale voltage generation circuit is exported the 3rd reference voltage and the 4th reference voltage by this first interior resistance string and this second interior resistance string.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101042976A CN101311782B (en) | 2007-05-25 | 2007-05-25 | Gray scale voltage generation circuit and its operation method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2007101042976A CN101311782B (en) | 2007-05-25 | 2007-05-25 | Gray scale voltage generation circuit and its operation method |
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| CN101311782A true CN101311782A (en) | 2008-11-26 |
| CN101311782B CN101311782B (en) | 2011-07-20 |
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| CN2007101042976A Expired - Fee Related CN101311782B (en) | 2007-05-25 | 2007-05-25 | Gray scale voltage generation circuit and its operation method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104505016A (en) * | 2015-01-13 | 2015-04-08 | 京东方科技集团股份有限公司 | Display driving circuit, display driving device, display device and driving method |
| CN104505051A (en) * | 2014-12-31 | 2015-04-08 | 深圳市华星光电技术有限公司 | Liquid crystal display and control method thereof |
| CN104700800A (en) * | 2015-01-07 | 2015-06-10 | 友达光电股份有限公司 | Gamma voltage generation circuit and gamma voltage generation method |
| WO2017028351A1 (en) * | 2015-08-20 | 2017-02-23 | 深圳市华星光电技术有限公司 | Liquid crystal display drive device and liquid crystal display drive method |
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| JP4878795B2 (en) * | 2005-08-16 | 2012-02-15 | ルネサスエレクトロニクス株式会社 | Display control circuit and display control method |
| CN100428325C (en) * | 2005-08-25 | 2008-10-22 | 凌阳科技股份有限公司 | Source circuit and method for driving liquid crystal display device |
| CN100444235C (en) * | 2005-09-30 | 2008-12-17 | 群康科技(深圳)有限公司 | Liquid-crystal display device and its driving circuit |
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| CN104505051A (en) * | 2014-12-31 | 2015-04-08 | 深圳市华星光电技术有限公司 | Liquid crystal display and control method thereof |
| WO2016106927A1 (en) * | 2014-12-31 | 2016-07-07 | 深圳市华星光电技术有限公司 | Liquid crystal display and control method therefor |
| CN104700800A (en) * | 2015-01-07 | 2015-06-10 | 友达光电股份有限公司 | Gamma voltage generation circuit and gamma voltage generation method |
| CN104700800B (en) * | 2015-01-07 | 2017-04-12 | 友达光电股份有限公司 | Gamma voltage generation circuit and gamma voltage generation method |
| CN104505016A (en) * | 2015-01-13 | 2015-04-08 | 京东方科技集团股份有限公司 | Display driving circuit, display driving device, display device and driving method |
| WO2017028351A1 (en) * | 2015-08-20 | 2017-02-23 | 深圳市华星光电技术有限公司 | Liquid crystal display drive device and liquid crystal display drive method |
| CN108458766A (en) * | 2018-04-20 | 2018-08-28 | 重庆电子工程职业学院 | A kind of low power-consumption intelligent flowmeter |
| CN108962180A (en) * | 2018-09-19 | 2018-12-07 | 昆山龙腾光电有限公司 | Gamma switching circuit and liquid crystal display device |
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| Publication number | Publication date |
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| CN101311782B (en) | 2011-07-20 |
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