JP2007171737A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which has display on a first scan line that will not be made obscure and is prevented from electrostatic breakdown. <P>SOLUTION: The liquid crystal display device includes a first substrate 3, a second substrate 4, and a liquid crystal 5 provided between both substrates 3 and 4. First to N-th (N is an integer equal to or larger than 2) scan lines g1 to g600 and a plurality of signal lines s1 to s2400 arranged in a matrix form, a dummy line 15 provided along the first scan line g1 in the vicinity of the outside of the first scan line, switching elements 25 connected to the first scan line g1 and respective signal lines s1 to s2400, auxiliary capacitors 26 connected between respective switching elements 25 and the dummy line 15, scan drive parts 31a and 31b for driving the scan lines g1 to g600, and signal drive parts 30a to 30e for driving the signal lines s1 to s2400 are provided on the first substrate 3, and the scan drive parts 31a and 31b always output a voltage equal to or lower than the non-selection time drive, voltage, to the dummy line 15 during scanning. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device.

Conventionally, this kind of apparatus is shown by patent document 1, for example. According to Patent Document 1, the scanning substrate 2 and the signal substrate 3 are bonded together by the seal portion 4. A dummy pattern 12 is provided near the outside of the first scanning line 6.
JP 2001-125124 A

  In the above apparatus, the dummy pattern 12 is provided, but there is a first disadvantage that no countermeasures for preventing electrostatic breakdown are taken. In order to eliminate this drawback, the present inventor manufactured an improved liquid crystal panel as shown in FIG. In FIG. 4, scanning lines G1 to G600 and signal lines S1 to S2400 are arranged in a matrix on the first substrate 101. A common wiring 102 is provided outside the scanning line G1.

  A second substrate (not shown) is provided above the paper surface of FIG. 4, and a liquid crystal 101 a is provided between the first substrate 101 and the second substrate. A common electrode (for example, DC 3.4 volts) is applied to the common wiring 102 via the common terminal 103. The scanning lines G1 to G600 and the signal lines S1 to S2400 are connected to the common wiring 102 via the electrostatic breakdown preventing measure 106. In this way, measures for preventing electrostatic breakdown are taken.

  Each switching element 104 is connected between the scanning line G1 and each signal line S1 to S2400. An auxiliary capacitor 105 is provided between each switching element 104 and the common wiring 102. However, the liquid crystal panel 100 has a second drawback that the display on the first scanning line G1 is unclear. As a result of investigation of the cause by the present inventor, the selection driving voltage is applied to the first scanning line G1, and the gradation voltage is written to the liquid crystal 101a and the auxiliary capacitor 105 from the signal lines S1 to S2400.

  Thereafter, a non-selection drive voltage (for example, −10 volts) is applied to the first scanning line G1. The auxiliary capacitor 105 is charged with a voltage V1. The gradation voltage output to the signal lines S1 to S2400 is usually 0 to 10 volts. Therefore, the voltage V1 = the gradation voltage−the common voltage = −3.4 to 6.6 volts is small.

  When this is not selected, the charging voltage of the auxiliary capacitor 105 gradually decreases due to the leakage current of the switching element 104 (for example, leakage from the drain to the gate). Therefore, it has been found that the display on the first scanning line G1 becomes unclear. Accordingly, the present invention provides a liquid crystal display device in which the display on the first scanning line is not blurred and electrostatic breakdown is prevented in consideration of such a conventional defect.

  In order to solve the above-mentioned problem, the present invention of claim 1 includes a first substrate, a second substrate, and a liquid crystal provided between both substrates, and is arranged in a matrix on the first substrate. Scanning lines from the first to Nth (N is an integer of 2 or more) and a plurality of signal lines, a dummy line provided in the vicinity of the first scanning line, and the first line Each switching element connected to the scanning line and each signal line, each auxiliary capacitor connected between each switching element and the dummy line, a scanning drive unit that drives each scanning line, and each signal line A signal driving unit for driving, and the scanning driving unit always outputs a voltage equal to or lower than a non-selected driving voltage to the dummy line during scanning.

  According to the second aspect of the present invention, each pixel electrode is provided near the intersection of each scanning line and each signal line, and each switching element is connected to each scanning line, each signal line, and each pixel electrode, and each auxiliary capacitor Are connected between each pixel electrode and the dummy line, and are connected between each pixel electrode and each scanning line.

  According to a third aspect of the present invention, a common electrode is provided on the back surface of the second substrate, a common wire disposed on the first substrate and connected to the common electrode is provided, and the common wire and the dummy line are provided. In between, an electrostatic breakdown preventing element was provided.

  As in the first aspect, the scanning drive section always outputs a voltage equal to or lower than the non-selection driving voltage to the dummy line during scanning. As a result, when the first scanning line is not selected, the charging voltage V2 of each auxiliary capacitor connected to the dummy line is V2 = output of the signal driver (gray scale voltage) − (voltage applied to the dummy line). . Therefore, V2 is very large compared to VI (charging voltage of each auxiliary capacitor in the improved liquid crystal panel). As a result, even if each auxiliary capacitor is discharged little by little, the voltage V2 is sufficiently large during one frame, so that the display on the first scanning line is prevented from becoming unclear.

  The scan driver outputs a drive voltage when not selected. When the applied voltage to the dummy line is equal to the non-selection drive voltage, the output of the scanning drive unit can be used as it is as the applied voltage. When the applied voltage to the dummy line is smaller than the non-selection drive voltage, the output of the scan drive unit via the resistor can be used as the applied voltage by providing a predetermined resistance or the like in the scan drive unit. Thus, with a simple configuration, a voltage equal to or lower than the non-selection driving voltage can be always output to the dummy line.

  As described in claim 2, by providing each pixel electrode between the dummy line and the first scanning line, the electrode functions as a dummy electrode. That is, even if static electricity enters through the dummy line, the dummy pixel electrode is destroyed, so that the pixel electrode connected to the second to Nth scanning lines is destroyed via each switch element. Can be prevented.

  As in the third aspect, the electrostatic breakdown preventing element is provided between the common wiring connected to the common electrode and the dummy line. As a result, even if static electricity is applied to the common wiring, a current due to the static electricity flows to the common electrode. As a result, when static electricity is generated, each auxiliary capacitor connected to the common wiring and each switching element can be prevented from being destroyed.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below in detail with reference to embodiments and the drawings. The embodiments described below exemplify liquid crystal display devices for embodying the technical idea of the present invention. However, the present invention is not intended to be specified in this embodiment, and the present invention is equally applicable to various modifications without departing from the technical concept shown in the claims. It can be applied.

  The liquid crystal display device 1 according to the present embodiment will be described below with reference to FIGS. FIG. 1 is a block diagram of the liquid crystal display device 1. FIG. 2 is an electric circuit diagram of a liquid crystal panel used in the liquid crystal display device 1. FIG. 3 is a partial cross-sectional view of a liquid crystal panel used in the liquid crystal display device 1.

  In FIG. 3, the liquid crystal panel 2 includes a first substrate 3, a second substrate 4, and a liquid crystal 5 provided between both the substrates 3 and 4. The first substrate 3 and the second substrate 4 are made of, for example, a glass substrate. A sealing agent 6 is formed to seal the liquid crystal 5.

  On the first substrate 3, a wiring 7 having a predetermined pattern and a drain electrode 8 are formed. An insulating layer 9 is formed so as to cover the wiring 7 and the drain electrode 8.

  Each pixel electrode 10 is formed on the insulating layer 9 so as to be electrically connected to each drain electrode. An alignment film 11 is formed so as to cover each pixel electrode.

  A black matrix 12 and a color filter layer 13 are formed on the back surface of the second substrate 4. For example, the color filter layer 13 is formed by sequentially repeating each of R, G, and B filters in a stripe shape.

  A common electrode 14 is formed so as to cover the black matrix 12 and the color filter layer 13. An alignment film 11 is formed so as to cover the common electrode 14.

  As shown in FIG. 2, on the first substrate 3, scanning lines g1 to g600 from the first to the Nth (N is an integer of 2 or more, for example, N = 600) and a plurality of signals are arranged in a matrix. Lines s1 to s2400 are formed.

  The left ends of the scanning lines g1 to g600 are connected to terminals G1 to G600, respectively. The lower ends of the signal lines s1 to s2400 are connected to the terminals S1 to S2400, respectively.

  The dummy line 15 is formed near the outside along the first scanning line g1. The left end of the dummy line 15 is connected to the terminal D. The common terminal 16 is formed on the first substrate 3.

  The left end of the common wiring 17 is connected to the common terminal 16, and the right end is connected to the common electrode 14 provided on the back surface of the second substrate 4 through a connection portion 18 made of gold or the like.

  The lower end of the common wiring 19 is connected to the connection portion 18, and the upper end is connected to the connection portion (made of gold or the like). The common wiring 21 has a left end connected to a connecting portion (made of gold or the like) 20 and a left end connected to a connecting portion 22 (made of gold or the like).

  The right end of the common wiring 23 is connected to the common wiring 19 and the left end is connected to the electrostatic breakdown preventing element 24. That is, the common wires 19 and 23 are disposed on the first substrate 3 and connected to the common electrode 14. An electrostatic breakdown preventing element 24 is formed between the common wirings 19 and 23 and the dummy line 15.

  Similarly, an electrostatic breakdown preventing element 24 is formed between the common wiring 19 and each of the scanning lines g1 to g600.

  Further, an electrostatic breakdown preventing element 24 is formed between the common wiring 21 connected to the common electrode 14 and the signal lines s1 to s2400.

  Next, the periphery of the dummy line 15 and the first scanning line g1 shown in FIG. 2 will be described. Each switching element 25 is connected to the first scanning line g1 and the signal lines s1 to s2400.

  Each switching element 25 is made of, for example, a TFT (thin film transistor). The source of each switching element 25 is connected to each signal line s1 to s2400. The gate of each switching element 25 is connected to the first scanning line g1.

  The drain of each switching element 25 is connected to one side of the liquid crystal 5 (the lower side of the liquid crystal 5 in FIG. 3). The other side of the liquid crystal 5 (the upper side of the liquid crystal 5 in FIG. 3) is connected to the common electrode 14.

  Each auxiliary capacitor 26 is connected between each switching element 25 and the dummy line 15. That is, one side of each auxiliary capacitor 26 is connected to the drain of the switching element 25, and the other side is connected to the dummy line 15. In the above description, the pixel electrode 10 is not formed.

  Next, the periphery of the scanning lines g2 to g600 will be described. Each pixel electrode 10 is provided near the intersection of each scanning line g2 to g600 and each signal line s1 to s2400.

  Each switching element 25 is connected to each pixel electrode 10, each scanning line g2 to g600, and each signal line s1 to s2400.

  Each auxiliary capacitor 26 is connected between each pixel electrode 10 and each scanning line g1 to g600.

  Unlike the above description, each pixel electrode 10 may be provided in the vicinity of the intersection of the first scanning line g1 and the signal lines s1 to s2400 as necessary. At this time, each auxiliary capacitor 26 is connected between each pixel electrode 10 and the dummy line 15.

  In the following description, an example in which the pixel electrode 10 is not formed between the first scanning line g1 and the dummy line 15 will be described. The liquid crystal panel 2 is constituted by the above components.

  Next, a liquid crystal display device 1 using the liquid crystal panel 2 will be described with reference to FIG. The liquid crystal display device 1 includes a liquid crystal panel 2, a control circuit 27, a power supply circuit 28, a gamma circuit 29, a plurality (for example, five) of signal driving units 30a, 30b, 30c, 30d, and 30e, It is comprised from the scanning drive part 31a, 31b etc. (for example, two pieces).

  The control circuit 27 receives a data enable signal DE sent from a computer, a television device, a video playback device, a DVD playback device (both not shown) and the like via an input interface (not shown).

  The control circuit 27 receives, for example, RGB 8-bit image data IRD, IGD, and IBD sent from the above-described device or the like. The control circuit 12 receives the dot clock signal DOTCLK, the vertical synchronization signal VSYNC, and the horizontal synchronization signal HSYNC.

  The control circuit 27 processes the input signal and outputs display data ORD, OGD, OBD, polarity inversion signal POL, strobe signal STRB, clock signal CLK, and the like to the signal drivers 30a to 30e.

  Further, the control circuit 27 outputs the vertical clock signal CPV to the scan driving units 31a and 31b. The control circuit 27 outputs a frame signal FLM to the scan drivers 31a and 31b.

  Further, the control circuit 27 outputs a control signal CONT indicating the power supply sequence to each component to the power supply circuit 28. In this manner, the control circuit 27 outputs various signals to the power supply circuit 28, the scan driving units 31a and 31b, and the signal driving units 30a to 30e.

  The power supply circuit 28 outputs an appropriate DC voltage to each component based on the input DC voltage VIN (for example, 12 volts). Specifically, the power supply circuit 28 outputs a first voltage VGEN (for example, 5 volts) to the gamma circuit 29.

  The power supply circuit 28 is used for driving the control circuit 27, the logic units (not shown) of the signal drivers 30a to 30e, and the logic units (not shown) of the scan drivers 31a and 31b. The voltage VDD (for example, 3.3 volts) is output.

  The power supply circuit 28 outputs the first voltage VGEN to each output unit (not shown) included in the signal driving units 30a to 30e.

  The power supply circuit 13 has a second voltage VGH (for example, DC 10 volts) and a third voltage VGL (for example, −15 volts) for each output unit (not shown) included in the scan driving units 31a and 31b. Is output.

  The gamma circuit 29 resistively divides the first voltage VGEN output from the power supply circuit 28 and the ground voltage (not shown), thereby applying gamma correction voltages VGM1 to VGM10 to the signal driving units 30a to 30e. Output.

  Each of the signal driving units 30a to 30e uses the gamma correction voltages VGM1 to VGM10 as a reference voltage for a built-in D / A converter (not shown).

  As a result, each of the signal driving units 30a to 30e performs analog conversion on the input display data ORD, OGD, and OBD, and the analog-converted gradation is applied to each of the signal lines s1 to s2400 via the built-in output unit. A voltage (for example, DC 0 to 10 volts) is output. Further, the power supply circuit 28 has a power supply IC 32.

  As described above, the signal driving units 30a to 30e drive the signal lines s1 to s2400. That is, the signal driving units 30a to 30e output gradation voltages in accordance with the display data ORD, OGD, and OBD to the signal lines s1 to s2400.

  The scan driving units 31a and 31b drive the scan lines g1 to g600. That is, the scan driving units 31a and 31b first output a selection driving voltage (for example, DC 10 volts) to the scanning line g1, and a non-selection driving voltage (for example, to the scanning lines g2 to g600). DC-10 volts) is output.

  Next, the scanning drive units 31a and 31b output a selection driving voltage to the scanning line g2, and output a non-selection driving voltage to the scanning lines g1, g3 to g600. In this way, the same operation is repeated.

  That is, the scanning drive units 31a and 31b sequentially scan the scanning lines g1 to g600 one by one. In this way, the scanning drive units 31a and 31b end the scanning of the first frame. Similarly, the scan driving units 31a and 31b scan the second frame to the nth frame.

  Further, the scanning drive unit 31a always outputs a voltage equal to or lower than the non-selection driving voltage to the dummy line 15 during the scanning. The liquid crystal display device 1 is composed of the above components.

  Next, a characteristic operation of the liquid crystal display device 1 will be described with reference to FIGS. As described above, the scan drive unit 31a always outputs a voltage equal to or lower than the non-selection drive voltage to the dummy line 15 during scanning. In the following description, for example, it is assumed that a non-selection drive voltage (for example, −10 volts) is output.

  First, the scanning drive units 31a and 31b output a selection driving voltage to the scanning line g1, and output a non-selection driving voltage to the scanning lines g2 to g600.

  At this time, the signal driving units 30a to 30e output gradation voltages to the signal lines s1 to s2400, respectively. At this time, each switching element 25 connected to the first scanning line g1 is turned on, and the gradation voltage is written in the liquid crystal 5 and each auxiliary capacitor 26.

  Next, the selection driving voltage is output to the scanning line g2, and the non-selection driving voltage is output to the scanning lines g1, g3 to g600. At this time, the voltage V2 is applied and charged to each auxiliary capacitor 26 connected to the first scanning line g1 via each switching element 25.

  For example, if the gradation voltage is 0 to 10 volts, the voltage V2 = gradation voltage− (voltage applied to the dummy line 15) = 10 to 20 volts. As a result, V2> V1. However, V1 is a voltage applied to each auxiliary capacitor 105 connected to the first scanning line G1 in the improved example as described above.

  As described above, the voltage V2 is extremely large as compared with the improved example. As described above, when the first scanning line g1 is not selected, the charging voltage of the auxiliary capacitor 26 gradually decreases due to the leakage current of the switching element 25. However, since the voltage V2 at the time of the first charge is sufficiently large, the voltage V2 is maintained at a sufficiently large value for one frame even if it is discharged little by little. As a result, the display on the first scanning line g1 is prevented from becoming unclear.

It is a block diagram of the liquid crystal display device 1 which concerns on the Example of this invention. FIG. 2 is an electric circuit diagram of a liquid crystal panel 2 used in the liquid crystal display device 1. 4 is a partial cross-sectional view of the liquid crystal panel 2. FIG. It is an electric circuit diagram of the liquid crystal panel which improved the prior art example.

Explanation of symbols

3 First substrate 4 Second substrate 5 Liquid crystal g1 to g600 Scan line s1 to s2400 Signal line 15 Dummy line 25 Switching element 26 Auxiliary capacitor 30a to 30e Signal drive unit 31a, 31b Scan drive unit

Claims (3)

A first substrate, a second substrate, and a liquid crystal provided between both substrates, and a first to Nth scan (N is an integer of 2 or more) arranged in a matrix on the first substrate. A plurality of signal lines, a plurality of signal lines, dummy lines provided near the outside along the first scanning lines, switching elements connected to the first scanning lines and the signal lines, Each auxiliary capacitor connected between the switching element and the dummy line, a scan driving unit for driving each scanning line, and a signal driving unit for driving each signal line, the scanning driving unit at the time of scanning A liquid crystal display device characterized in that a voltage equal to or lower than a non-selected driving voltage is always output to the dummy line. Each pixel electrode is provided near the intersection of each scanning line and each signal line, each switching element is connected to each scanning line, each signal line, and each pixel electrode, and each auxiliary capacitor is connected to each pixel electrode and each dummy 2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is connected between each pixel electrode and each scanning line. A common electrode is provided on the back surface of the second substrate, a common wiring disposed on the first substrate and connected to the common electrode is provided, and an electrostatic breakdown is provided between the common wiring and the dummy line. 2. A liquid crystal display device according to claim 1, further comprising a prevention element.

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