JPH0643690U - Printed wiring board for display panel drive circuit - Google Patents

Abstract

(57) [Summary] [Structure] On the surface of a glass epoxy sheet 33 having a thickness of 50 μm, a terminal arrangement pattern 35 connected to the electrode arrangement portion of the display panel 15 and a drive circuit pattern on which electronic parts such as ICs are mounted. 37, a connection wiring pattern 39 connecting the terminal arrangement pattern 35 and the drive circuit pattern 37 was formed, and the portion of the connection wiring pattern 39 was used as a bent portion. [Effect] With the glass epoxy sheet, the flexibility required for the bent wiring can be obtained, and since the thermal expansion is small, the connection by the hot press can be surely performed to the display panel having the extremely small electrode arrangement pitch. Since the terminal arrangement pitch can be reduced, the drive circuits can be integrated on two sides, which is advantageous for downsizing and cost reduction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a printed wiring board used for a drive circuit of a display panel.

[0002]

[Prior art]

 Display panels such as liquid crystal display panels and plasma display panels are used as display devices for small televisions and small computers. FIG. 3 shows a configuration example of a television using a liquid crystal display panel. The liquid crystal display panel 1 has a structure in which a liquid crystal matrix 5 and a drive circuit 7 are formed on a glass substrate 3. The drive circuits 7 are arranged on the respective sides of the liquid crystal matrix 5, one set of drive circuits facing each other on the two sides is for the X-axis, and the other set of drive circuits is for the Y-axis. The television signal received by the antenna 9 is amplified, separated and converted by the main board 11, distributed by the control circuit 13 to each drive circuit 7, and displayed as an image on the liquid crystal matrix 5.

When the drive circuit 7 is arranged around the liquid crystal matrix 5 as shown in FIG. 3, the panel becomes large relative to the screen. As a modification of this, there is a display panel as shown in Fig. 4. This is because the liquid crystal display panel 15 in which only the liquid crystal matrix 5, the X-axis and Y-axis electrodes are formed on the glass substrate 3, and the drive circuit board 17 in which electronic components 19 such as ICs are mounted are separately manufactured. The tape-shaped wiring material 21 is connected to each other, and the tape-shaped wiring material 21 is bent to arrange the drive circuit 17 on the back side of the liquid crystal display panel 15. However, this structure has many connection points, and thus has a drawback in that a connection failure is likely to occur.

Therefore, as shown in FIG. 5, a flexible drive circuit in which an electronic component 19 such as an IC is mounted on an FPC (flexible printed wiring board) 23 in which a drive circuit pattern and a terminal array pattern are formed on the surface of a polyimide film. There is also proposed a structure in which the substrate 25 and the liquid crystal display panel 15 as described above are separately formed, and the terminal portions of the flexible drive circuit board 25 are directly connected to the electrode portions of the liquid crystal display panel 15.

[0005]

[Problems to be solved by the device]

 However, in order to connect the terminal part of the flexible drive circuit board to the electrode part of the display panel, it is necessary to insert an anisotropic conductive film between them and hot press at a temperature of about 170 ° C. At this time, the FPC that uses a polyimide film has a much larger thermal expansion than the substrate (usually glass) of the display panel, so the terminals and electrodes arranged with minute pitches may be misaligned, resulting in poor connection. There's a problem. In particular, recently, as the display panel has become higher in image quality, the electrode pitch of the display panel has become finer, and there is a situation where the FPC using a polyimide film cannot handle it.

[0006]

[Means for Solving the Problems]

 In view of the above problems, the present invention provides a printed wiring board for a drive circuit of a display panel, which can cope with higher image quality and higher density of the display panel, and the structure thereof is glass with a thickness of 70 μm or less. On the surface of the epoxy sheet, a terminal array pattern connected to the electrode array part of the display panel, a drive circuit pattern that mounts electronic parts such as ICs to form a drive circuit of the display panel, the terminal array pattern and the drive. A connecting wiring pattern that connects between the circuit patterns is formed, and the portion of the connecting wiring pattern is a bent portion.

[0007]

[Action]

 Conventionally, a wiring board using a glass epoxy sheet was generally considered to be a rigid flat plate, and it was considered that the wiring board was not flexible enough to allow bent wiring. A printed wiring board using a glass epoxy sheet with a thickness of 70 μm or less (50 ± 20 μm) is not as flexible as an FPC using a conventional polyimide film, but is flexible enough to withstand bending wiring. Turned out to have. Since a wiring board using such a glass epoxy sheet has a smaller thermal expansion than a wiring board using a polyimide film, it is possible to reliably connect the display panel to the fine pitch electrodes by hot pressing.

[0008]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. The printed wiring board 31 for a display panel drive circuit uses a glass epoxy sheet 33 having a thickness of 50 μm as an insulating substrate. On the surface of the glass epoxy sheet 33, a terminal arrangement pattern 35 connected to the electrode arrangement portion of the display panel 15, a drive circuit pattern 37 for mounting an IC and other electronic parts to form a drive circuit of the display panel, A connection wiring pattern 39 connecting between the terminal array pattern 35 and the drive circuit pattern 37 is formed. Reference numeral 35a is an individual terminal, 37a is an IC mounting portion having a pad array portion around it, and 39a is an individual connection wiring.

The glass epoxy sheet 33 is obtained by impregnating a glass fiber woven cloth having a thickness of 38 μm, which is a plain weave of glass fibers with a density of 56 warps × 56 wefts / inch, with an epoxy resin. Copper foil is attached to both surfaces of the glass epoxy sheet 33 by a conventional method, and pattern etching is performed to form the terminal arrangement pattern 35, the drive circuit pattern 37, and the connection wiring pattern 39.

The arrangement pitch of the terminals of the terminal arrangement pattern 35 is, for example, 760 μm (319 terminals) when terminals for one direction (X-axis direction or Y-axis direction) are arranged on two opposite sides of the display panel 15. However, when terminals for one direction (X-axis direction or Y-axis direction) are collectively arranged on one side of the display panel 15, the size is 380 μm (638 terminals). In particular, a terminal arrangement with a pitch of 380 μm cannot be supported by a conventional FPC using a polyimide film.

The printed wiring board 31 for the display panel drive circuit is used as shown in FIG. That is, after the IC 19 is mounted on the IC mounting portion 37a and the terminal arrangement pattern 35 is connected to the electrode arrangement portion of the display panel 15 via the anisotropic conductive film 41 by a hot press (170 ° C.), the connection wiring pattern 39 is formed. By bending the part, the part of the drive circuit pattern 37 is arranged on the back side of the display panel 15.

[0012]

[Effect of device]

 As described above, in the printed wiring board for a display panel drive circuit according to the present invention, the flexibility required for the bent wiring is obtained by using the glass epoxy sheet with a thickness of 70 μm or less for the insulating substrate. Moreover, since the thermal expansion is small, it is possible to reliably connect to the display panel with an extremely small electrode array pitch by hot pressing. In addition, since the terminal arrangement pitch can be made small, it is possible to combine the drive circuits conventionally provided on the four sides of the display panel into two sides, which is advantageous for downsizing and cost reduction.

[Brief description of drawings]

FIG. 1 is a plan view showing a printed wiring board for a display panel driving circuit according to an embodiment of the present invention.

FIG. 2 is a front view showing a usage state of the printed wiring board of FIG.

FIG. 3 is an explanatory diagram showing an example of a television using a liquid crystal display panel.

FIG. 4 is a plan view showing an example of a conventional display panel.

FIG. 5 is a plan view showing another example of a conventional display panel.

[Explanation of symbols]

 15: Display Panel 19: IC 31: Display Panel Printed Circuit Board for Drive Circuit 33: Glass Epoxy Sheet 35: Terminal Arrangement Pattern 35a: Terminal 37: Drive Circuit Pattern 37a: IC Mounting Section 39: Contact Wiring Pattern 39a: Contact Wiring 41 : Anisotropic conductive film

Front Page Continuation (72) Inventor Kazuyuki Yamamori 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A drive for forming a drive circuit of a display panel by mounting a terminal array pattern connected to an electrode array part of the display panel and an electronic component such as an IC on the surface of a glass epoxy sheet having a thickness of 70 μm or less. A printed wiring board for a display panel drive circuit, characterized in that a circuit pattern and a connecting wiring pattern connecting the terminal arrangement pattern and the driving circuit pattern are formed, and a portion of the connecting wiring pattern is a bent portion.