CN101572061A - Data-driven integrated circuit of liquid crystal display device - Google Patents
Data-driven integrated circuit of liquid crystal display device Download PDFInfo
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- CN101572061A CN101572061A CNA2008101056085A CN200810105608A CN101572061A CN 101572061 A CN101572061 A CN 101572061A CN A2008101056085 A CNA2008101056085 A CN A2008101056085A CN 200810105608 A CN200810105608 A CN 200810105608A CN 101572061 A CN101572061 A CN 101572061A
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Abstract
The invention provides a data-driven integrated circuit of a liquid crystal display device, which comprises a serial-to-parallel conversion unit, a shift register, a latch, a digital-to-analog converter, a switching unit and an output buffer, wherein the switching unit is positioned between each digital-to-analog converter and the corresponding output buffer, and controls the input end of the output buffer to connect the output end of the digital-to-analog converter or pre-charging level through Load signals; when the Load signals are in high level, the input end of the output buffer is connected with pre-charging voltage; and when the Load signals are in low level, the input end of the output buffer is connected with the output end of the digital-to-analog converter. The data-driven integrated circuit can effectively reduce charging time of a pixel capacitor of a pixel point of a drive circuit.
Description
Technical field
The present invention relates to the liquid crystal indicator Driving technique, relate in particular to a kind of data-driven integrated circuit (IC) of liquid crystal indicator.
Background technology
At present, the world has entered the information revolution epoch, and display technique and display device have occupied crucial status in the evolution of infotech.And, become the direction of display technique development because flat pannel display has little, radiationless, the advantage such as do not glimmer of in light weight, thin thickness, volume.
In flat panel display, Thin Film Transistor-LCD (TFT LCD) has characteristics low in energy consumption, that manufacturing cost is relatively low and radiationless, has occupied leading position in flat panel display market.
Fig. 1 is the drive principle synoptic diagram of thin film transistor liquid crystal display screen pixel, and as shown in Figure 1, each pixel in the LCDs can be regarded liquid crystal capacitance C in parallel as
LCWith memory capacitance C
Stg, described liquid crystal capacitance C
LCWith memory capacitance C
StgBe also referred to as pixel capacitance.One end of pixel capacitance is connected to the source electrode of TFT101, and the drain electrode of TFT101 then is connected to the data line 106 of LCDs; And the other end of pixel capacitance is connected on the common electric voltage (VCOM) of LCDs.Capacitor C
dIt is the distributed capacitance between data line 106 and the VCOM.
The corresponding pixel charging voltage of gray shade scale is followed in one of data-driven IC output, and this voltage must pass through data line and TFT switch, just arrives pixel electrode at last.Because data line exists distributed resistance and distributed capacitance, we simply can be expressed as R
dAnd C
d, its synoptic diagram as shown in Figure 2.We know that LCDs generally adopts positive and negative AC driving pixel in order to prevent that liquid crystal is easily aging under direct drive; In order to improve the display frame quality, the driving of LCDs generally adopts a upset or 1 mode that adds 2 counter-rotatings to drive pixel, shown in Fig. 5 a and 5b.
Under an inversion driving mode, it is that positive polarity drives that data-driven IC drives current pixel, is that negative polarity drives when then next line drives, and like this, data-driven IC drives before the current line, must neutralize distributed capacitance C on the data line earlier
dIn again the current line pixel is charged behind the residual opposite polarity electric charge of lastrow.Add under 2 inversion driving modes for 1, owing to be one counter-rotatings of two row, so only when counter-rotating takes place polarity, just the electric charge that previous row is remained on the distributed capacitance of data line neutralizes.
The concrete principle of work block diagram of data-driven IC comprises as shown in Figure 3: serial converter 301, bidirectional shift register 302, latch 303, digital/analog converter 304 and output buffer 305, wherein,
The gray-scale data that TCON sends be a pixel then a pixel transmit, and during data-driven IC output, be that the data of whole one-row pixels are exported simultaneously, therefore, need to use shift register that described gray-scale data is converted into data line.Wherein, bidirectional shift register is meant the direction of displacement that shift register can be set, and promptly both can shift to last pixel data by first pixel data of delegation, also can shift to first pixel data from last pixel data of delegation.
Wherein, during the rising edge of Load signal, the pixel data of a described full line that obtains in the bidirectional shift register 302 can send to latch 303 and preserve, in case after bidirectional shift register 302 sends to latch 303 with the pixel data of a described full line, bidirectional shift register 302 will be proceeded the displacement of next line pixel data.
Latch 303, be used to preserve the gray-scale data of the described one-row pixels of bidirectional shift register 302 outputs, the pixel data that drives display screen so just can not be subjected to the influence of next line shift register content variation, and the pixel data that latch will drive display screen is transferred to digital/analog converter (DAC) 304.
Digital/analog converter 304, the digital signal that is used for the described pixel data that will receive changes into aanalogvoltage, and described aanalogvoltage is sent to output buffer 305.
The voltage of 64 gray shade scales of 6bit can generate by the dividing potential drop that data-driven IC positive internal voltage drives 63 resistance string in 63 resistance string in district and negative voltage driving district.And, therefrom extract 14 points out as reference voltage, be referred to as gamma reference voltage V1～V14 again, can adjust the output of drive integrated circult by regulating these 14 gamma reference voltages, can obtain the gamma curve of required LCDs.
The purpose of amplifying is to make described aanalogvoltage to have the ability that drives LCDs.Wherein, during the negative edge of Load signal, output buffer 305 is wanted the output of gray-scale displayed voltage with LCDs, remains to till the rising edge of next Load signal always, and when the Load high level, data-driven IC is output as high-impedance state.The output waveform of data integrated circuit as shown in Figure 4.
Wherein, in the prior art, the circuit diagram of digital/analog converter 304 among the data-driven IC and output buffer 305 parts generally as shown in Figure 6, behind each digital/analog converter 602, all connect an output buffer 601, output buffer 601 amplifies corresponding aanalogvoltage, obtains final output voltage Y1～Yn.Wherein, the value of n depends on the number of pixels that every row comprised in the LCDs.
Mention above, when LCD added 2 inversion modes driving LCDs at an inversion mode or 1, when driving polarity changed, the output of drive integrated circult at first needed data line distributed capacitance C
dIn the residual opposite polarity charging neutrality of lastrow, and then data line distributed capacitance and pixel capacitance carried out the charging of polarity opposite charges.Charging neutrality in the data line distributed capacitance needs the regular hour, if our charging neutrality in the negative edge of load signal just begins the data line distributed capacitance, this must take the duration of charging of one part of pixel point, under fixing line frequency, also just reduced the duration of charging of pixel, this is for high-resolution LCDs, and the charge rate that this can have influence on the LCDs pixel influences picture quality.
At present, can use electric charge to share (charge sharing) method, when Load signal high level, with adjacent two the output internal short-circuits of data-driven IC, because LCD has adopted some counter-rotating, then adjacent output is just in time opposite, so, during adjacent two output short-circuits, left and right sides adjacent data line can neutralize positive and negative charge just by drive IC internal short-circuit circuit, when this all shows same gray shade scale to all pixels,, will have good effect because positive and negative charge is identical just; But, when if picture displayed just in time is black and white screen, it is bigger that gray shade scale differs, and the positive and negative charge that adjacent data line drives pixel is not just in time equal, at this moment puts up with and can not neutralize fully, therefore, in this case, electric charge is shared (charge sharing) and can't will be fallen the charging neutrality in the data line distributed capacitance, so also residual many identical electric charges of lastrow polarity in the DATA DISTRIBUTION electric capacity, in the load negative edge and the time, can take duration of charging of pixel.
Summary of the invention
In view of this, fundamental purpose of the present invention is to provide a kind of data-driven integrated circuit of liquid crystal indicator, can effectively increase the duration of charging of drive integrated circult to the pixel capacitance of pixel.
For achieving the above object, technical scheme of the present invention is achieved in that
The invention provides a kind of data-driven integrated circuit of liquid crystal indicator, comprise serial converting unit, shift register, latch, digital/analog converter and output buffer; This data-driven integrated circuit also comprises switching device shifter,
Described switching device shifter is between each digital/analog converter and corresponding output buffer, and described switching device shifter links to each other with the output terminal of digital/analog converter or links to each other with pre-charge level by the input end of Load signal controlling output buffer; And,
When the Load signal was high level, the input end of output buffer linked to each other with pre-charge voltage, and when the Load signal was low level, the input end of output buffer linked to each other with the output terminal of digital/analog converter.
Wherein, described switching device shifter is made up of two switches, wherein,
One end of a switch links to each other with pre-charge voltage, and the other end links to each other with the input end of output buffer; One end of another switch links to each other with the output terminal of digital/analog converter, and the other end links to each other with the input end of output buffer; And,
Described switch closure when the Load signal is high level disconnects during low level;
Described another switch disconnects closure during low level during for high level when the Load signal.
Described switch is that bipolar transistor switching tube or field effect transistor switch pipe or other can be integrated in circuit switch inside device.
Described pre-charge voltage is half (1/2) AVDD of data-driven integrated circuit driving voltage or the gamma reference voltage central value of data-driven integrated circuit.
The preparation method of described (1/2) AVDD voltage is: two resistors that resistance is identical that between AVDD and ground, are connected in series, and the voltage that connects on the lead of described two resistors is (1/2) AVDD; The gamma reference voltage central value also can be carried out the dividing potential drop acquisition to the anode of same GTG and the gamma voltage of negative terminal by the resistance of two similar resistance.
The data-driven integrated circuit of liquid crystal indicator provided by the present invention, by between digital/analog converter and output buffer, increasing a switching device shifter, utilize the output of the high-low level controlling and driving IC of load signal, make that the voltage signal of inputoutput buffer is a pre-charge voltage when load is high level; When load is low level, the voltage signal of inputoutput buffer is the grayscale voltage that digital/analog converter is exported, thereby between Load signal high period, promptly from the rising edge to the negative edge during this period of time in, the voltage of drive integrated circult output is pre-charge voltage, drive integrated circult just neutralizes to positive and negative charge in the distributed capacitance of data line or the part neutralization, just only need begin to continue charging when next line polarity drives on the contrary in existing zero charge or under near the zero charge state, this just has been equivalent to increase the duration of charging of drive integrated circult to the pixel charging.Further, increased the driving force of data-driven integrated circuit.
Description of drawings
Fig. 1 is the drive principle synoptic diagram of prior art thin film transistor liquid crystal display screen pixel;
Fig. 2 drives the principle schematic of single pixel for the prior art data-driven integrated circuit;
Fig. 3 is the principle of work synoptic diagram of prior art data-driven integrated circuit;
Fig. 4 is the output waveform synoptic diagram of prior art data-driven integrated circuit;
Fig. 5 a is prior art LCD point inversion driving mode synoptic diagram;
Fig. 5 b is that prior art LCD 1 adds 2 inversion driving mode synoptic diagram;
Fig. 6 is a prior art data drive circuit part-structure synoptic diagram;
Fig. 7 is a data drive circuit part-structure synoptic diagram of the present invention;
Fig. 8 is the output waveform synoptic diagram of data-driven integrated circuit of the present invention.
Embodiment
Basic thought of the present invention is: by increase a switching device shifter between each digital/analog converter output buffer corresponding with described converter, this switching device shifter is by the voltage signal of the high-low level control inputoutput buffer of Load signal, and then the output of control data drive integrated circult, make when the Load signal is high level, the voltage signal of inputoutput buffer is a pre-charge voltage, and when the Load signal was low level, the voltage signal of inputoutput buffer was the aanalogvoltage that digital/analog converter is exported.Between Load signal high period, promptly from the rising edge to the negative edge during this period of time in, the voltage of drive integrated circult output is pre-charge voltage, drive integrated circult just neutralizes to positive and negative charge in the distributed capacitance of data line or the part neutralization, just only need begin to continue charging when next line polarity drives on the contrary in existing zero charge or under near the zero charge state, this just has been equivalent to increase the duration of charging of drive integrated circult to the pixel charging.
Below, be described with reference to the accompanying drawings the realization of the data-driven integrated circuit of liquid crystal indicator of the present invention by specific embodiment.
Fig. 7 is the data-driven IC structural representation of liquid crystal indicator of the present invention, as shown in Figure 7, compare with Fig. 6 of the prior art, between each digital/analog converter 602 of prior art and corresponding output buffer 601, increased a switching device shifter, pre-charge level input end and control signal load signal input part.Each switching device shifter by two K switch n and Kn0 form (n=1,2 ... .), wherein, the circuit of the corresponding output of n Yn.Described switch can be integrated in switching device in the integrated circuit for bipolar transistor switching tube or field effect transistor switch pipe or other.
Because each bar line construction of output Y1～Yn is identical, is that example describes with the circuit of exporting Y1.As shown in Figure 7, an end a1 of K switch 1 links to each other with pre-charge voltage VA, and the other end b1 of K switch 1 links to each other with the input end of output buffer 601.One end a10 of K switch 10 links to each other with the output terminal of digital/analog converter 602, and the other end b10 of K switch 10 links to each other with the input end of output buffer 601.The Load signal is used for the closure and the disconnection of driving switch K1 and K switch 10.Closure when K switch 1 is high level at the Load signal disconnects during low level.K switch 10 disconnects closure during low level at the Load signal during for high level.
Thus, when the Load signal is high level, K switch 1 closure, K10 disconnects, the voltage signal of inputoutput buffer 601 is pre-charge voltage VA, at this moment, the no show still of the negative edge of Load signal, pre-charge voltage VA is input to output buffer 601, amplify in the input data line of back by output buffer 601, the voltage of drive integrated circult output at this moment is exactly VA, this voltage can carry out pre-charge for the distributed capacitance of data line, in and the data line distributed capacitance in electric charge, when the Load signal transfers low level to by high level, be that negative edge arrives, K switch 1 disconnects, the K10 closure, in the aanalogvoltage inputoutput buffer 601 of digital/analog converter 602 outputs, when carrying out the driving of liquid crystal display pixel electrode by output buffer 601 amplifications, the voltage of drive integrated circult output is exactly from the voltage of gray-scale data through the digital/analog converter conversion, this voltage just on the basis that pre-charge voltage neutralizes in advance to the distributed capacitance of data line continuation the distributed capacitance and the pixel capacitance of data line charged.
Described pre-charge voltage VA can be the gamma voltage central value of (1/2) data-driven integrated circuit driving voltage (AVDD) or data-driven integrated circuit.But, this pre-charge voltage can make logarithm according in the line distributed capacitance and after the electric charge stayed in the data line distributed capacitance be (VA-VCOM) * C
dWherein, (1/2) AVDD can obtain by circuit as shown in Figure 7, that is: AVDD connects an end of resistor R 1, the other end of resistor R 1 links to each other with an end of resistor R 2, the end ground connection that resistor R 2 is not connected with resistor R 1, and R1 is identical with the resistance of R2, at this moment, under the state of not considering the lead resistance, any point voltage on the lead of connection R1 and R2 is (1/2) AVDD.When lead between R1 and the R2 was connected, pre-charge voltage VA was (1/2) AVDD with VA.
When use as shown in Figure 7 circuit structure and during switching device, when the Load signal is high level, the voltage signal of inputoutput buffer 601 is half of AVDD voltage, and when the Load signal is low level, the voltage signal of inputoutput buffer 601 is the aanalogvoltage that digital/analog converter 602 is exported, C as shown in Figure 8
dIn.At this moment, data-driven IC is except high level that can the output cathode driving, low level that negative polarity drives, can also output voltage be the intermediate level of driving voltage, this drive integrated circult can be exported three grades of level, is called the data integrated circuit of multipole output again.
In addition, the gamma voltage central value that pre-charge voltage VA also can the application data drive integrated circult among Fig. 7, gamma voltage central value also can be carried out dividing potential drop to the gamma voltage of the anode of same GTG and negative terminal by the resistance of two similar resistance and obtained.At this moment, when the Load signal was high level, the voltage of inputoutput buffer 601 was the gamma reference voltage center voltage, and this voltage is also relatively near VCOM, when the Load signal was low level, the voltage of inputoutput buffer 601 was the aanalogvoltage of digital/analog converter output.Like this, also can be to a certain extent earlier in and the electric charge on the distributed capacitance of data line, the duration of charging of electric charge when reducing Load signal negative edge.
The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention.
Claims (5)
1, a kind of data-driven integrated circuit of liquid crystal indicator comprises serial converting unit, shift register, latch, digital/analog converter and output buffer; It is characterized in that this data-driven integrated circuit also comprises switching device shifter,
Described switching device shifter is between each digital/analog converter and corresponding output buffer, and described switching device shifter links to each other with the output terminal of digital/analog converter or links to each other with pre-charge level by the input end of Load signal controlling output buffer; And,
When the Load signal was high level, the input end of output buffer linked to each other with pre-charge voltage, and when the Load signal was low level, the input end of output buffer linked to each other with the output terminal of digital/analog converter.
2, the data-driven integrated circuit of liquid crystal indicator according to claim 1 is characterized in that, described switching device shifter is made up of two switches, wherein,
One end of a switch links to each other with pre-charge voltage, and the other end links to each other with the input end of output buffer; One end of another switch links to each other with the output terminal of digital/analog converter, and the other end links to each other with the input end of output buffer; And,
Described switch closure when the Load signal is high level disconnects during low level;
Described another switch disconnects closure during low level during for high level when the Load signal.
3, the data-driven integrated circuit of liquid crystal indicator according to claim 2 is characterized in that, described switch is that bipolar transistor switching tube or field effect transistor switch pipe or other can be integrated in circuit switch inside device.
According to each described data-driven integrated circuit of claim 1 to 3, it is characterized in that 4, described pre-charge voltage is half (1/2) AVDD of data-driven integrated circuit driving voltage or the gamma reference voltage central value of data-driven integrated circuit.
5, data-driven integrated circuit according to claim 4, it is characterized in that, the preparation method of described (1/2) AVDD voltage is: two resistors that resistance is identical that between AVDD and ground, are connected in series, and the voltage that connects on the lead of described two resistors is (1/2) AVDD; The gamma reference voltage central value also can be carried out the dividing potential drop acquisition to the anode of same GTG and the gamma voltage of negative terminal by the resistance of two similar resistance.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105185337A (en) * | 2011-09-30 | 2015-12-23 | 株式会社日本显示器 | Driving circuit and video line driving circuit |
| CN110517647A (en) * | 2019-08-30 | 2019-11-29 | 上海中航光电子有限公司 | The driving method and liquid crystal display device of liquid crystal display panel |
| CN111261125A (en) * | 2020-03-19 | 2020-06-09 | 合肥京东方显示技术有限公司 | Data driver, control method thereof and display device |
| CN112669781A (en) * | 2020-12-14 | 2021-04-16 | 北京奕斯伟计算技术有限公司 | Display processing method, display processing device and display panel |
-
2008
- 2008-04-30 CN CNA2008101056085A patent/CN101572061A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105185337A (en) * | 2011-09-30 | 2015-12-23 | 株式会社日本显示器 | Driving circuit and video line driving circuit |
| CN105185337B (en) * | 2011-09-30 | 2018-01-30 | 株式会社日本显示器 | Drive circuit and video line drive circuit |
| CN110517647A (en) * | 2019-08-30 | 2019-11-29 | 上海中航光电子有限公司 | The driving method and liquid crystal display device of liquid crystal display panel |
| CN111261125A (en) * | 2020-03-19 | 2020-06-09 | 合肥京东方显示技术有限公司 | Data driver, control method thereof and display device |
| CN111261125B (en) * | 2020-03-19 | 2021-10-22 | 合肥京东方显示技术有限公司 | Data driver, control method thereof and display device |
| CN112669781A (en) * | 2020-12-14 | 2021-04-16 | 北京奕斯伟计算技术有限公司 | Display processing method, display processing device and display panel |
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Application publication date: 20091104 |