JP2006126294A - Planar display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure a sufficient interval between conductors on a flexible wiring board which is to be integrated with a drive IC. <P>SOLUTION: A planar display device comprises a display panel DP; a wiring substrate section BP whereon a bus wiring BS is formed; drive circuits YD and XD which include a plurality of drive ICs 20, respectively integrated with a plurality of flexible wiring boards 21, each being arranged between the display panel DP and the wiring substrate section BP, and drive the display panel DP; and a controller 5 for controlling the drive circuits YD and XD via the bus wiring BS. Especially, each drive IC 20 is arranged, out of alignment with the center in a direction along the outer periphery of the display panel DP so as to make the wiring pattern of the corresponding flexible wiring board 21 asymmetric. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flat display device in which a plurality of driving IC packages are provided along an outer edge of a display panel.

  For example, flat display devices such as liquid crystal display devices are widely used as monitor displays for computers, car navigation systems, television receivers, and the like.

  A liquid crystal display device generally includes a liquid crystal display panel including a matrix array of a plurality of liquid crystal pixels, and a display control circuit that controls the liquid crystal display panel. The liquid crystal display panel has a structure in which a liquid crystal layer is sandwiched between an array substrate and a counter substrate.

  The array substrate has a plurality of pixel electrodes arranged in a substantially matrix, a plurality of scanning lines arranged along a row of the plurality of pixel electrodes, a plurality of signal lines arranged along a column of the plurality of pixel electrodes, and a plurality of And a plurality of switching elements arranged in the vicinity of the intersection positions of the scanning lines and the plurality of signal lines. Each switching element is formed of, for example, a thin film transistor (TFT), and conducts when the corresponding scanning line is driven, and applies the potential of the corresponding signal line to the corresponding pixel electrode. A common electrode is provided on the counter substrate so as to face the plurality of pixel electrodes arranged on the array substrate. The pair of pixel electrodes and the common electrode constitute a pixel together with a pixel region which is a part of the liquid crystal layer located between these electrodes, and the liquid crystal molecule arrangement is controlled by an electric field between the pixel electrode and the common electrode in the pixel region. The display control circuit includes a scanning line driving circuit that drives a plurality of scanning lines, a signal line driving circuit that drives a plurality of signal lines, and a controller that controls the scanning line driving circuit and the signal line driving circuit. In general, the scanning line driving circuit and the signal line driving circuit are configured by a plurality of scanning line driving ICs and signal line driving ICs arranged along the outer edge of the display panel. Each drive IC is a tape carrier package (TCP) integrated with a flexible wiring board.

  In the case where the liquid crystal display device is mainly used for a television receiver that displays a moving image, use of an OCB mode liquid crystal display panel in which liquid crystal molecules exhibit good response has been studied (see Patent Document 1). In this liquid crystal display panel, the liquid crystal is in a spray orientation almost lying down before power-on by an alignment film rubbed in parallel with each other on the pixel electrode and the common electrode. The liquid crystal display panel performs a display operation after the liquid crystal is changed from the spray alignment to the bend alignment by a relatively strong electric field applied in the initialization process when the power is turned on.

In the case of a liquid crystal display device for a television receiver, the display panel is required to have not only the responsiveness described above but also high definition and a high aspect ratio. For this reason, the number of signal lines tends to increase significantly. Since the number of signal line driving ICs increases as the number of signal lines increases, a plurality of tape carrier packages are arranged between the bus wiring board on which the bus wiring is formed and the display panel, and the controller board is independent from the bus wiring board. It is conceivable to commonly control the signal line driver ICs from the controller arranged above via the bus wiring. In this case, the manufacturing cost can be reduced by making the controller board smaller than the bus wiring board.
JP 2002-202491 A

  By the way, the bus wiring of the above-mentioned bus wiring board includes a scanning line driving circuit control bus and a power supply bus in addition to the signal line driving circuit control bus, and the scanning line driving circuit control signal and power supply voltage are used as the signal line driving circuit. The plurality of tape carrier packages arranged along the outer edge of the display panel are supplied to the display panel side through the one located at the outermost contour.

  A conventional tape carrier package has a structure in which a signal line driving IC is arranged at the center of a flexible wiring board as shown in FIG. The flexible wiring board includes a bridge wiring for drawing a control bus for the scanning line driving circuit and a power supply bus into the display panel, and the bridge wiring is formed redundantly on both sides of the signal line driving IC. The scanning line driving circuit is connected to the scanning line driving circuit control bus on the bus wiring substrate via one of wiring formed in the display panel and bridge wiring formed on both sides of the signal line driving IC.

  However, if the size of the signal line driving IC of each tape carrier package increases due to the increase in the size of the display panel or the number of wirings of the control bus for the scanning line driving circuit and the power supply bus increases, it is integrated with the signal line driving IC. It becomes difficult to ensure a sufficient wiring interval in the flexible wiring board.

  An object of the present invention is to provide a flat display device capable of ensuring a sufficient wiring interval in a flexible wiring board integrated with a driving IC.

  According to the present invention, a display panel includes a display panel, a wiring board portion on which bus wiring is formed, and a plurality of driving ICs each integrated with a plurality of flexible wiring boards respectively disposed between the display panel and the wiring board portion. Drive circuit and a controller for controlling the drive circuit via the bus wiring, and each drive IC from the center in the direction along the outer edge of the display panel so as to make the wiring pattern of the corresponding flexible wiring board asymmetric. A flat display device is provided that is offset.

  In this flat display device, each driving IC is arranged so as to be shifted from the center in the direction along the outer edge of the display panel so as to make the wiring pattern of the corresponding flexible wiring board asymmetric. That is, since a wide empty space is created on the side opposite to the side where the drive IC is shifted in the flexible wiring board, an auxiliary wiring such as a bridge wiring connecting the display panel and the wiring board portion is formed in this empty space. It is possible to secure a sufficient wiring interval in the wiring. Therefore, the auxiliary wiring can be arranged on the desired side without wasting the width of the flexible wiring board as in the case where the auxiliary wiring is redundantly provided on both sides of the drive IC.

  Hereinafter, an active matrix liquid crystal display device according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 schematically shows a circuit configuration of the liquid crystal display device. The liquid crystal display device includes a liquid crystal display panel DP and a display panel control circuit CNT connected to the display panel DP. The liquid crystal display panel DP has a structure in which a liquid crystal layer 3 is sandwiched between an array substrate 1 and a counter substrate 2 which are a pair of electrode substrates. The display panel control circuit CNT controls the transmittance of the liquid crystal display panel DP by the liquid crystal driving voltage applied from the array substrate 1 and the counter substrate 2 to the liquid crystal layer 3.

  The array substrate 1 includes a plurality of pixel electrodes PE arranged in a substantially matrix on a transparent insulating substrate such as glass, and a plurality of scanning lines Y (Y1 to Ym) arranged along a row of the plurality of pixel electrodes PE. , A plurality of signal lines X (X1 to Xn) arranged along a column of the plurality of pixel electrodes PE, and arranged near the intersection position of the scanning lines Y and the signal lines X and driven through the corresponding scanning lines Y, respectively. In this case, the corresponding signal line X and the corresponding pixel electrode PE are conducted to have a plurality of pixel switching elements W. Each pixel switching element W is formed of, for example, a thin film transistor, the gate of the thin film transistor is connected to the scanning line Y, and the source-drain path is connected between the signal line X and the pixel electrode PE.

  The counter substrate 2 includes, for example, a color filter disposed on a transparent insulating substrate such as glass, and a common electrode CE disposed on the color filter so as to face the plurality of pixel electrodes PE. Each pixel electrode PE and common electrode CE is made of a transparent electrode material such as ITO (Indium Tin Oxide), and is covered with an alignment film, and is controlled to a liquid crystal molecular arrangement corresponding to the electric field from the pixel electrode PE and common electrode CE. A pixel PX is configured together with a pixel region which is a part of the liquid crystal layer 3.

  Each of the plurality of pixels PX has a liquid crystal capacitor CLC between the pixel electrode PE and the common electrode CE, and an auxiliary capacitor Cs is connected in parallel to the liquid crystal capacitor CLC.

  The display panel control circuit CNT includes a pair of scanning line drive circuits YD that sequentially drive the plurality of scanning lines Y1 to Ym so that the plurality of switching elements W are conducted in units of rows. A signal line driving circuit XD for outputting the pixel voltage Vs to the plurality of signal lines X1 to Xn during a period of conduction by driving, and a pair of scanning line driving circuit YD and signal line driving circuit XD for a video signal input from the outside. Including a controller 5 for controlling the operation timing and the like. The pixel voltage Vs is a voltage applied to the pixel electrode PE with the common voltage Vcom of the common electrode CE as a reference, and the polarity is periodically inverted with respect to the common voltage Vcom.

  The pair of scanning line drive circuits YD have the same structure and are arranged on both sides of the array substrate 1 in the direction along the plurality of scanning lines Y. The signal line drive circuit XD is disposed on one side of the array substrate 1 in the direction along the plurality of signal lines X. The controller 5 designates the control signal CTY for sequentially driving the plurality of scanning lines Y, the serial pixel data DATA obtained from the video signal in units of pixels PX for one row, and the output polarity, and the pixel data DATA. A control signal CTX to be assigned to each of the plurality of signal lines X, a predetermined number of gradation reference voltages VREF used to convert the image data DATA to the pixel voltage Vs, and the like are generated. The control signal CTY and the compensation voltage are supplied from the controller 5 to the pair of scanning line drive circuits YD, and the control signal CTX, pixel data DATA, and gradation reference voltage VREF are supplied from the controller 5 to the signal line drive circuit XD.

  The scanning line driving circuit YD sequentially selects a plurality of scanning lines Y1 to Ym in one frame period under the control of the control signal CTY, and turns on the on-voltage that causes the pixel switching elements W in each row to conduct only for one horizontal scanning period. Supply. The signal line driving circuit XD converts the pixel data DATA supplied to the pixels PX for one row every horizontal scanning period into pixel voltages Vs with reference to a predetermined number of gradation reference voltages VREF, and Output in parallel to the signal lines X1 to Xn.

  For example, when the scanning line driving circuit YD drives the scanning line Y1 with an on-voltage to make all the pixel switching elements W connected to the scanning line Y1 conductive, the pixel voltage Vs on the signal lines X1 to Xn is switched to these pixels. It is supplied to the pixel electrodes PE for one row through the elements W, respectively.

  FIG. 2 shows an external wiring structure of the liquid crystal display device shown in FIG. As shown in FIG. 2, the liquid crystal display device includes first to fourth bus wiring boards BPA, BPB, BPC, and BPD as wiring board portions BP in which bus wirings BS extending along the outer edge of the display panel DP are formed. Have. The first and second bus wiring boards BPA and BPB are provided for the signal line driving circuit XD, and the third and fourth bus wiring boards PBC and BPD are provided for the pair of scanning line driving circuits YD. Each of these scanning line drive circuits YD is constituted by a plurality of tape carrier packages TCP1 each connected to a plurality of scanning lines Y by a predetermined number. Each tape carrier package TCP1 is formed by mounting a scanning line driving IC 10 on a flexible wiring board 11 and integrating them. The signal line driving circuit XD is configured by a plurality of tape carrier packages TCP2 each connected to a plurality of signal lines X by a predetermined number. Each tape carrier package TCP2 is obtained by mounting a signal line driving IC 20 on a flexible wiring board 21 and integrating them.

  In each of the pair of scanning line driving circuits YD, the flexible wiring board 11 of all the tape carrier packages TCP1 is disposed between the display panel DP and the third bus wiring board BPC or between the display panel DP and the fourth bus wiring board BPD. . In the signal line driving circuit XD, half of the flexible wiring boards 21 of the tape carrier package TCP2 are arranged between the display panel DP and the first bus wiring board BPA, and the remaining half of the flexible wiring boards 21 of the tape carrier package TCP2 are connected to the display panel DP. And between the second bus wiring boards BPB.

  The controller 5 is connected to the bus wiring BS and disposed on the controller board CP independent of the wiring board portion BP, and controls the scanning line driving circuit YD and the signal line driving circuit XD via the bus wiring BS. The first and second bus wiring boards BPA, BPB and the controller board CP are connected by the connector CN and the flexible wiring material FB. As the flexible wiring material FB, a flexible wiring board, a flexible flat cable, or the like is used. The bus wiring BS of the first and second bus wiring boards BPA and BP2 supplies a control bus for the scanning line driving circuit YD for supplying the control signal CTY, the control signal CTX, the pixel data DATA, the gradation reference voltage VREF, and the like. It includes a control bus for the signal line driving circuit XD, and a power supply bus for supplying operating voltages for the scanning line driving circuit YD, the signal line driving circuit XD, and the like. The bus lines BS of the third and fourth bus wiring boards BPC and BPD include a control bus for the scanning line driving circuit YD that supplies a control signal CTY and the like. The bus wiring BS of the first bus wiring board BPA and the bus wiring BS of the second bus wiring board BPB are independent from each other and are common on the controller board CP.

  Here, the controller 5 is connected to the control bus for the scanning line driving circuit YD, the control bus for the signal line driving circuit XD, and the power supply bus in each of the first and second bus wiring boards BPA and BPB. In particular, the control bus for the signal line driver circuit XD on the first bus wiring board BPA and the control bus for the signal line driver circuit XD on the second bus wiring board BPB may be independent in order to shorten the wiring length. preferable. On the end side far from the boundary between the first and second bus wiring boards BPA and BPB, the bus wiring BS of the first bus wiring board BPA and the bus wiring BS of the second bus wiring board BPB (specifically, scanning line driving) Circuit YD control bus and power supply bus) are respectively drawn into the display panel DP through the flexible wiring board 21 closest to the end, and further, the bus wiring BS (specifically, the control bus for the scanning line driving circuit YD) is provided. It is connected to the bus wiring BS of the third and fourth bus wiring boards BPC and BPD via the nearest flexible wiring board 11, respectively.

  3 shows a planar structure of the first group of tape carrier packages TCP2 arranged between the display panel DP and the first bus wiring board BPA, and FIG. 4 is arranged between the display panel DP and the second bus wiring board BPB. The plane structure of the tape carrier package TCP2 of the second group is shown. In each tape carrier package TCP2, the flexible wiring board 21 has a signal line driving wiring 22 used for input / output of the signal line driving IC 20 and a scanning line driving wiring 23 used for controlling the scanning line driving circuit YD. The signal line driving circuit XD bus on the first and second bus wiring boards BPA and BPB is connected to the signal line driving IC 20 by the signal line driving wiring 22, and the output portion of the signal line driving IC 20 is the signal line driving wiring. 22 is connected to a predetermined number of signal lines X. The scanning line driving circuit YD buses on the first and second bus wiring boards BPA and BPB are connected to wirings on the display panel DP respectively directed to the pair of scanning line driving circuits YD by the scanning line driving wirings 23. For the power buses on the first and second bus wiring boards BPA and BPB, the signal line driving wiring 22 is assigned to the power bus portion for the signal line driving circuit XD, and the scanning line driving wiring 23 is the scanning line. Allocated to the power supply bus portion for the drive circuit.

  In the first group of tape carrier packages TCP2, the signal line driving IC 20 is arranged on the right side of the flexible wiring board 21 in the direction along the outer edge of the display panel DP. On the other hand, in the tape carrier package TCP2 of the second group, the signal line driving IC 20 is shifted to the left from the center of the flexible wiring board 21 in the direction along the outer edge of the display panel DP. Thereby, a wide empty space can be formed on the side opposite to the signal line driving IC 20 in the flexible wiring board 21, and the scanning line driving wiring 23 is formed in this empty space. Here, the scanning line driving wiring 23 is a direction along the outer edge of the display panel DP as a bridge wiring for drawing at least a part of the bus wiring BS on the first and second wiring boards BPA and BPB into the display panel DP. In the empty space not occupied by the signal line driving IC 20.

  Accordingly, the scanning line driving wiring 23 is located on one side of the signal line driving IC 20 in the first group of flexible wiring boards 21 arranged between the first bus wiring board BPA and the display panel DP, and the second bus wiring board BPB. And in the 2nd group flexible wiring board 21 arrange | positioned between display panels DP, it will be located in the other side of the signal line drive IC20.

  In such a configuration, the scanning line driving circuit YD control bus and the power supply bus, which are part of the bus wiring BS on the first bus wiring board BPA, are the left scanning line driving among the flexible wiring boards 21 of the first group. A control bus for the scanning line driving circuit YD, which is drawn into the display panel DP through the scanning line driving wiring 23 of the wiring board 21 closest to the circuit YD and is part of the bus wiring BS on the second bus wiring board BPB, and The power supply bus is drawn into the display panel DP through the scanning line driving wiring 23 of the wiring board 21 closest to the right scanning line driving circuit YD among the flexible wiring boards 21 of the second group.

  In the above-described embodiment, each signal line driving IC 20 is arranged so as to be shifted from the center in the direction along the outer edge of the display panel DP so that the wiring pattern of the corresponding flexible wiring board 21 is asymmetric. That is, since a wide empty space is formed on the side opposite to the side where the signal line driving IC 20 is shifted in the flexible wiring board 21, it is like a bridge wiring (scanning line driving wiring 23) connecting the display panel DP and the bus wiring boards BPA and BPB. By forming a simple auxiliary wiring in this empty space, it is possible to secure a sufficient wiring interval G that facilitates the mounting of the auxiliary wiring and improves the reliability at the time of mounting. Therefore, the auxiliary wiring can be arranged on the desired side without wasting the width of the flexible wiring board 21 as in the case where the auxiliary wiring is redundantly provided on both sides of the signal line driving IC 20.

  In addition, this invention is not limited to the above-mentioned embodiment, It can deform | transform variously in the range which does not deviate from the summary.

  In the above-described embodiment, the pair of scanning line driving circuits YD are arranged on both sides of the display panel DP. However, a single scanning line driving circuit YD may be arranged on one side of the display panel DP.

  In the above-described embodiment, the active matrix liquid crystal display device has been described as an example. However, the present invention can be applied to various liquid crystal display devices regardless of the liquid crystal driving method. Therefore, for example, the present invention can be applied to a liquid crystal display device that directly drives a liquid crystal pixel via the scanning line X and the signal line X without using the pixel switching element W. Further, the present invention can be applied to a flat display device such as a liquid crystal display device using a TN liquid crystal pixel, an FED device using a self-light emitting element as a pixel, and an organic EL display device as long as the display panel is controlled from the outside. it can.

1 is a diagram schematically showing a circuit configuration of an active matrix liquid crystal display device according to an embodiment of the present invention. It is a figure which shows the external wiring structure of the liquid crystal display device shown in FIG. It is a figure which shows the planar structure of the tape carrier package of the 1st group arrange | positioned between the display panel shown in FIG. 2, and a 1st bus wiring board. It is a figure which shows the planar structure of the tape carrier package of the 2nd group arrange | positioned between the display panel shown in FIG. 2, and a 2nd bus wiring board. It is a figure which shows the planar structure of the conventional tape carrier package.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Array substrate, 2 ... Opposite substrate, 3 ... Liquid crystal layer, 5 ... Controller, 10 ... Scan line drive IC, 11 ... Flexible wiring board, 20 ... Signal line drive IC, 21 ... Flexible wiring board, 22 ... Signal line drive Wiring, 23 ... scanning line driving wiring, TCP1, TCP2 ... tape carrier package, BP ... wiring board, BPA, BPB, BPC, BPD ... bus wiring board, BS ... bus wiring, PS ... bypass wiring, CP ... controller Substrate, DP ... liquid crystal display panel, PE ... pixel electrode, CE ... common electrode, CLC ... liquid crystal capacitor, Cs ... auxiliary capacitor, PX ... liquid crystal pixel, W ... switching element, Y ... scanning line, X ... signal line, CN ... Connector, FB ... flexible wiring material, CNT ... display panel control circuit, YD ... scanning line drive circuit, XD ... signal line drive circuit.

Claims (7)

The display panel is driven by including a display panel, a wiring board portion on which bus wiring is formed, and a plurality of driving ICs respectively integrated with the display panel and a plurality of flexible wiring boards arranged between the wiring board portions. A driving circuit and a controller for controlling the driving circuit via the bus wiring, each driving IC from the center in the direction along the outer edge of the display panel so as to make the wiring pattern of the corresponding flexible wiring board asymmetrical A flat display device characterized by being displaced. The flexible wiring board includes a bridge wiring for drawing at least a part of the bus wiring on the wiring board portion into the display panel, and the bridge wiring is not occupied by the drive IC in a direction along an outer edge of the display panel. The flat display device according to claim 1, wherein the flat display device is disposed in an empty space. The wiring board portion includes first and second bus wiring boards, and the bridge wiring is positioned on one side of the drive IC in a first group of flexible wiring boards disposed between the first bus wiring board and the display panel. 3. The flat display device according to claim 2, wherein the flat panel display device is located on the other side of the drive IC in a second group of flexible wiring boards disposed between the second bus wiring substrate and the display panel. A part of the bus wiring on the first bus wiring board is drawn into the display panel via any bridge wiring of the first group of flexible wiring boards, and one of the bus wirings on the second bus wiring board is drawn. The flat display device according to claim 3, wherein the portion is pulled into the display panel through any bridge wiring of the second group of flexible wiring boards. The display panel includes a plurality of pixels arranged in a substantially matrix, a plurality of scanning lines arranged along a row of the plurality of pixels, a plurality of signal lines arranged along a column of the plurality of pixels, and A plurality of switching elements that are arranged in the vicinity of intersection positions of the plurality of scanning lines and the plurality of signal lines and that connect the corresponding signal lines to corresponding pixels when selected via the corresponding scanning lines, A scanning line driving circuit for driving the plurality of scanning lines and a signal line driving circuit for driving the plurality of signal lines, wherein the signal line driving circuit is constituted by the plurality of driving ICs. 2. A flat display device according to 2. The flat display device according to claim 5, wherein the bridge line includes at least one of the control bus for the scanning line driving circuit and a power supply bus. 2. The flat display device according to claim 1, wherein the driving IC is integrated with the flexible wiring board to constitute a tape carrier package.

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