JP2004177578A - Electronic module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic module which can deal with high densification and has high reliability of electrical connection. <P>SOLUTION: The electronic module 100 is provided with an electronic circuit board 4 having circuit elements and signal lines connected to the circuit elements on a main surface and having substrate terminals connected to each of the signal lines, a plurality of driving circuit boards 8 packaged to the electronic circuit board adjacently to each other, and a wiring board 10 for supplying prescribed signals to each of the driving circuit boards 8. The wiring board 10 has terminals respectively at the major surface and rear side surface facing the same direction as the direction of the main surface of the electronic circuit board 4. The one driving circuit board 8 is electrically connected to the terminals on the main surface of the wiring board 10 and the other driving circuit board 8 is electrically connected to the terminals on the rear side surface of the wiring board 10. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic module, and more particularly, to a mounting structure of an electronic circuit board, a drive circuit board, and a wiring board.
[0002]
[Prior art]
For example, as a method of mounting an LSI driver on a display device, there is a tape automatic bonding (TAB) technology. Specifically, this is a method of connecting a TCP configured by mounting an LSI driver on a flexible substrate made of polyimide as a base material to a display panel and a printed circuit board. The printed board has a multilayer structure composed of, for example, four epoxy resin layers. A thin copper foil layer is formed between the epoxy resin layers, and a circuit is patterned on the copper foil layer. The circuit of the copper foil layer is connected to an electric signal input terminal formed on one side of the printed circuit board. The input terminal of the printed circuit board is thermocompression-bonded to TCP via an anisotropic conductive layer.
[0003]
2. Description of the Related Art In recent years, high definition (miniaturization of pixels) of a display device has become mainstream, and accordingly, the pitch of a display panel and terminals of a TCP have been narrowed. However, narrowing the pitch causes problems such as short-circuiting between adjacent terminals and difficulty in positioning.
[0004]
In addition, as the definition of the display device becomes higher, the size of the LSI driver increases, and the size of the TCP increases. When the size of the TCP increases, there is a problem that the outer size of the display device increases.
[0005]
Therefore, a display device shown in FIG. 6 is proposed in Patent Document 1.
[0006]
FIG. 6 is a partial schematic view of the liquid crystal display device disclosed in Patent Document 1. In this liquid crystal display device, TCPs 4 a and 4 b having an LSI driver 5 are mounted in a terminal area 2 of a liquid crystal panel 1. The shapes of the adjacent TCPs 4a and 4b are different from each other. In this liquid crystal display device, input terminals 6b of TCPs 4a and 4b mounted adjacent to the liquid crystal panel 1 are arranged in a staggered manner on the printed circuit board 3. In the above-mentioned liquid crystal display device, the pitch of the input terminals of the TCP can be set to be somewhat wide.
[0007]
A display device shown in FIG. 7 is proposed in Patent Document 2.
[0008]
FIG. 7 is a partial schematic view of the liquid crystal display device disclosed in Patent Document 2. As shown in FIG. 7, in the liquid crystal display device of Patent Document 2, a TCP 4 having an LSI driver 5 is mounted in a terminal area 2 of a liquid crystal panel 1.
[0009]
The TCP 4 has a via barrel shape in which the area near the center is wider than the end area where the input terminal 6 and the output terminal 7 are formed. Therefore, even if the size of the LSI driver 5 increases, the increase in the outer size of the TCP is suppressed. Further, a bent portion 8 is provided at a portion where adjacent TCPs overlap. Therefore, even when a plurality of TCPs are mounted close to each other, the TCP and the LSI driver 5 of the adjacent TCP are configured not to overlap.
[0010]
[Patent Document 1]
JP-A-5-173166 (FIG. 1)
[Patent Document 2]
JP-A-9-90392 (FIG. 2)
[0011]
[Problems to be solved by the invention]
However, the above-described conventional liquid crystal display device cannot sufficiently cope with a case where a higher definition of the display device is required. In the above description, the problem in the conventional display device is described by taking the liquid crystal display device as an example. However, the above problem is not limited to the liquid crystal display device, but also occurs in other display devices such as an organic EL display device. Further, the same problem occurs not only in the case of a display device but also in a case where high density (narrow pitch) is required in various electronic modules.
[0012]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic module with high electrical connection reliability that can cope with high density.
[0013]
[Means for Solving the Problems]
An electronic module according to an aspect of the invention includes a plurality of circuit elements and a plurality of signal lines connected to each of the plurality of circuit elements on a main surface, and a plurality of circuit elements connected to each of the plurality of signal lines. An electronic circuit board having a substrate terminal, a first drive circuit board and a second drive circuit board, each having a drive circuit, mounted on the electronic circuit board adjacent to each other, and the first drive circuit board and An electronic module comprising: a wiring board for supplying a predetermined signal to each of the second drive circuit boards, wherein the wiring board has a main surface facing the same direction as the main surface of the electronic circuit board; The first drive circuit board has a plurality of terminals on a back surface opposed to the main surface, and the first drive circuit board is electrically connected to the plurality of terminals on the main surface of the wiring board. The drive circuit board is Wherein said plurality of being electrically connected to a terminal of the back surface of the line board, thereby the problem is solved.
[0014]
The plurality of substrate terminals are formed on the main surface of the electronic circuit board and a back surface opposite to the main surface, and the first drive circuit board and the second drive circuit board have a plurality of An input terminal and a plurality of output terminals, wherein the plurality of input terminals and the plurality of output terminals of the first drive circuit board are respectively the plurality of terminals on the main surface of the wiring board and the electronic circuit board And the plurality of input terminals and the plurality of output terminals of the second drive circuit board are electrically connected to the plurality of substrate terminals of the second drive circuit board, respectively. And the plurality of board terminals on the back surface of the electronic circuit board.
[0015]
It is preferable that the main surface of the first drive circuit board and the main surface of the second drive circuit board are arranged so as to face in opposite directions.
[0016]
The plurality of substrate terminals formed on the back surface of the electronic circuit board extend from the main surface of the electronic circuit board to the back surface via an end surface existing between the main surface and the back surface. It is preferable to be connected to the plurality of signal lines.
[0017]
The wiring board includes the plurality of terminals connected to the plurality of input terminals of the first drive circuit board in a first terminal area, and is connected to the plurality of input terminals of the second drive circuit board. The plurality of terminals provided in a second terminal region, and at least a part of the first terminal region and at least a part of the second terminal region when viewed from a normal direction of the main surface of the wiring board. May overlap each other.
[0018]
Between the plurality of input terminals of the first drive circuit board and the plurality of terminals of the wiring board, between the plurality of input terminals of the second drive circuit board and the plurality of terminals of the wiring board, The plurality of output terminals of the first drive circuit board and the plurality of board terminals of the electronic circuit board, and the plurality of output terminals of the second drive circuit board and the plurality of boards of the electronic circuit board An anisotropic conductive layer may be arranged between the terminal and the terminal.
[0019]
Preferably, the first drive circuit board and the second drive circuit board are substantially the same.
[0020]
Preferably, the wiring board is made of PWB.
[0021]
A liquid crystal display device is suitably configured using the electronic module described above.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described by taking a liquid crystal module used for an active matrix type liquid crystal display device as an example. However, the present invention is widely applied to an electronic module used for an electronic device such as an organic EL display device or an image sensor. Can be applied.
[0023]
The liquid crystal module of the present embodiment includes an active matrix substrate (electronic circuit substrate), a driving circuit substrate mounted on the active matrix substrate, and a wiring substrate for supplying a predetermined signal to the driving circuit substrate. On the main surface of the active matrix substrate, switching elements (circuit elements) and signal lines connected to the switching elements are provided. The active matrix substrate is further provided with substrate terminals connected to the signal lines.
[0024]
The wiring substrate has a main surface facing in the same direction as the main surface of the active matrix substrate and a back surface facing the main surface, and terminals are provided on each of the main surface and the back surface. The drive circuit board (first drive circuit board) is electrically connected to the terminal on the main surface of the wiring board, and is another drive circuit board mounted on the active matrix substrate adjacent to the drive circuit board. The (second drive circuit board) is electrically connected to terminals on the back surface of the wiring board.
[0025]
In the above-described liquid crystal module, terminals provided on the wiring board for electrical connection with the drive circuit board are arranged on each of the main surface and the back surface of the wiring board. Therefore, the terminals can be arranged at a wider pitch than in a case where the terminals are arranged in a line only on the main surface of the wiring board, so that a short circuit can be prevented, and the mounting accuracy and the yield can be increased. Therefore, a liquid crystal module with high reliability of electrical connection that can cope with high definition is provided.
[0026]
In the wiring board, a terminal connected to the input terminal of the first drive circuit board is provided in a first terminal area of the wiring board, and a terminal connected to the input terminal of the second drive circuit board is provided on the wiring board. In the case where the second terminal region is provided in the second terminal region, for example, the first terminal region and the second terminal region may be partially overlapped with each other when viewed from the normal direction of the main surface of the wiring board. it can. By arranging the terminal regions on the wiring board as described above, the pitch of the terminals can be made wider.
[0027]
Note that, in this specification, a “terminal” is a portion that is electrically connected to a wiring or the like and is a portion that can be electrically connected to another conductive member. It is not necessary to be provided at the end of the wiring or the like, and the wiring and the terminal may or may not be integrally formed using the same material.
[0028]
In one embodiment, substrate terminals are formed on both the main surface of the active matrix substrate and the back surface facing the main surface. When terminals and substrate terminals are provided on the wiring substrate and the active matrix substrate, respectively, as described above, substantially the same drive circuit board can be used for the first and second drive circuit boards, thereby increasing the manufacturing cost. Can be suppressed.
[0029]
Specifically, it is mounted as follows using first and second drive circuit boards formed of substantially the same drive circuit board.
[0030]
Each of the first and second drive circuit boards has an input terminal and an output terminal on the same surface (main surface). The input terminals of the first drive circuit board are electrically connected to the terminals formed on the main surface of the wiring board, and the output terminals are electrically connected to the board terminals formed on the main surface of the active matrix substrate. Connecting. Also, the input terminals of the second drive circuit board are electrically connected to the terminals formed on the back surface of the wiring board, and the output terminals are electrically connected to the board terminals formed on the back surface of the active matrix substrate. I do. The first and second drive circuit boards are mounted such that their main surfaces face in opposite directions.
[0031]
In one embodiment, a substrate terminal formed on the back surface of the active matrix substrate has a signal line extending from the main surface of the active matrix substrate to the back surface via an end surface existing between the main surface and the back surface. It is connected.
[0032]
Hereinafter, a liquid crystal module 100 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the liquid crystal module 100.
[0033]
As shown in FIG. 1, the liquid crystal module 100 includes a display panel 2, a TCP (tape carrier package) 8, and a printed wiring board 10. The display panel 2 includes an active matrix substrate 4, an opposing substrate 6 disposed to face the substrate 4, and a liquid crystal layer (not shown) disposed between the two substrates. The liquid crystal module 100 exemplifies a case where a TCP and a printed wiring board (PWB) are used as the driving circuit board and the wiring board, respectively, but the driving circuit board and the wiring board are not limited to these. For example, COF (chip-on-film) or the like may be used for the drive circuit board.
[0034]
The active matrix substrate 4 includes, for example, a TFT for driving a pixel as a switching element, and has a source line and a gate line connected to the TFT as a signal line. Each of the source line and the gate line has a substrate terminal, and these substrate terminals are electrically connected to the output terminal of the TCP. The counter substrate 6 has a counter electrode (not shown) on the liquid crystal layer side surface. The TCP 8 is connected to the printed wiring board 10. The printed wiring board 10 is connected to, for example, an FPC (not shown), and a predetermined signal or the like is supplied from an external circuit board via the FPC.
[0035]
In the following description, the surface of the active matrix substrate 4 on which TFTs and signal lines are provided may be referred to as the display panel 2 or the main surface of the active matrix substrate 4.
[0036]
Hereinafter, the liquid crystal module 100 will be described in detail.
[0037]
First, the printed wiring board 10 and the TCP 8 will be described with reference to FIGS. FIG. 2A is a partial plan view showing a 2A region of the liquid crystal module 100 shown in FIG. 1, and FIG. 2B is a view of the liquid crystal module 100 shown in FIG. is there. As will be described later, FIG. 2 illustrates a TCP 8 having a shape different from that of the TCP 8 shown in FIG. FIG. 3 is a cross-sectional view corresponding to 3A-3A ′ of the printed wiring board 10 shown in FIG.
[0038]
As shown in FIGS. 2 and 3, the printed wiring board 10 has the terminals 12 on both the main surface 22 and the back surface 24. Among the plurality of terminals 12, a terminal 12A connected to the input terminal of the TCP 8A is formed on the main surface 22 of the printed wiring board 10, and is a terminal connected to the input terminal of the TCP 8B mounted adjacent to the TCP 8A. 12B is formed on the back surface 24 of the printed wiring board 10.
[0039]
The pitch of the terminals 12 is set wider than when the terminals are arranged in a line only on the main surface of the printed wiring board 10. That is, when the printed wiring board 10 is viewed from the normal direction of the main surface 22, the terminal region where the terminal 12A is provided and the terminal region where the terminal 12B is provided partially overlap. The terminals 12A and the terminals 12b are provided on different surfaces of the printed wiring board 10, respectively, so that even if they are arranged as described above, there is no short circuit.
[0040]
As shown in FIG. 3, the printed wiring board 10 has a multilayer structure of an insulating layer (for example, an epoxy resin layer) 18. A copper foil layer 20 in which a predetermined circuit is patterned is formed between the insulating layers 18 and on the main surface 22 and the back surface 24. Further, a through hole 16 whose inside is filled with a conductive material is provided at a predetermined position of the insulating layer 18, and the separated copper foil layer 20 is electrically connected by the through hole 16. The printed wiring board 10 has the above-described configuration, and can extract signals and the like from the terminals 12A on the main surface 22 and the terminals 12B on the back surface 24.
[0041]
The TCP 8 includes a drive circuit (for example, a driver LSI) 9, an input terminal (not shown in FIG. 2) electrically connected to the output terminal 12 of the printed wiring board 10, and a substrate terminal (not shown in FIG. 2) of the liquid crystal panel 2. And an output terminal (not shown in FIG. 2) that is electrically connected to the output terminal. The input terminal and the output terminal are provided on the same surface (main surface) of the TCP 8, and the drive circuit 9 is provided on the back surface opposite to the main surface. The TCPs 8 used in the liquid crystal module 100 are substantially the same. The pitch of the input terminals of the TCP 8 is set wider than in the related art in accordance with the pitch of the terminals 12 of the printed wiring board 10 described above.
[0042]
The plurality of TCPs 8 are mounted such that the main surfaces of adjacent TCPs 8 face in opposite directions. As shown in FIG. 2A, for example, in the four TCPs 8, the surface on which the drive circuit 9 is provided (the back surface) is arranged on the display surface side (upper side) of the liquid crystal module 100 in the order from the direction of the arrow 2 </ b> B, and opposite to the display surface Side (the lower side), the display surface side (the upper side), and the opposite side (the lower side) of the display surface. 2B. Among the two TCPs 8 shown in FIG. 2B, the TCP 8A in which the drive circuit 9 is mounted so as to face upward is present in the foreground when viewed from the direction of the arrow 2B in FIG. The TCP 8B, on which the drive circuit 9 is mounted so as to face downward, is located behind the TCP 8A when viewed from the direction of the arrow 2B.
[0043]
In the liquid crystal module 100 shown in FIG. 2A, when viewed from the normal direction of the main surface of the display panel 2, the adjacent TCPs 8 partially overlap not only in the terminal region but also outside the terminal region, The mounting is performed so that the overlapping area 14 is formed. For example, when the size of the driving circuit 9 mounted on the TCP 8 increases and the outer size of the TCP 8 increases, not only does the terminal region of the adjacent TCP partially overlap as shown in FIG. 2A, the same number of TCPs 8 can be mounted in a narrower area when they are superimposed, so that an increase in the outer size of the display device can be suppressed.
[0044]
Next, the active matrix substrate 4 included in the display panel 2 will be described with reference to FIG.
[0045]
FIG. 4 is a view of the active matrix substrate 4 shown in FIG. 1 as viewed from the direction of arrow 4A.
[0046]
As shown in FIG. 4, the active matrix substrate 4 has a main surface 38, a back surface 42 facing the main surface 38, and an end surface 40 arranged between the main surface 38 and the back surface 42. The signal line 28 extends to the back surface 42 via the end surface 40. Each signal line 28 has, for example, a substrate terminal 28A on the main surface 38 and a substrate terminal 28B on the back surface 42, so that signals and the like can be extracted from both the main surface 38 and the back surface 42. ing.
[0047]
The signal line 28 and the substrate terminal are formed, for example, as follows. For example, the signal wiring 28 is formed by mask evaporation using a material such as Al (TaN). After forming the signal lines 28, an insulating film is formed so as to cover the signal lines 28. An opening is formed in a predetermined region of the insulating film to expose a predetermined portion of the signal line, and this portion is used as a substrate terminal.
[0048]
Note that, as long as the signal line 28 and the output terminal 44 of the TCP 8 can be electrically connected to both the main surface 38 and the back surface 42 of the active matrix substrate 4, the signal line and the substrate terminal are not limited to the above-described configuration. . For example, of the signal lines 28, only predetermined signal lines may be selectively extended to the rear surface 42 via the end surface 40.
[0049]
FIG. 5A is a cross-sectional view corresponding to 5A-5A ′ of the liquid crystal module 100 shown in FIG. 1, and FIG. 5B is a cross-sectional view corresponding to 5B-5B ′. FIG. 5C schematically shows the 5C portion of FIG. 5A as viewed from the normal direction of the main surface of the display panel 2. FIG. 5D schematically shows a view of the 5D portion in FIG. 5B viewed from the normal direction of the main surface of the display panel 2.
[0050]
As shown in FIGS. 5A and 5C, the output terminal 48 of the TCP 8A is connected to the substrate terminal 28A on the main surface 42 of the active matrix substrate 4. The input terminal 46 of the TCP 8A is connected to the terminal 12A on the main surface of the printed wiring board 10. Further, as shown in FIGS. 5B and 5D, the output terminal 48 of the TCP 8B is connected to the substrate terminal 28B on the back surface 38 of the active matrix substrate 4. The input terminal 46 of the TCP 8B is connected to the terminal 12B on the back surface of the printed wiring board 10. The TCP 8 is thermocompression-bonded to the display panel 2 and the wiring substrate 10 with the anisotropic conductive layer (ACF) 44 interposed therebetween, and electrical connection between corresponding terminals is made via the ACF 44. In FIGS. 5C and 5D, a broken line region 30 indicates a region that is thermocompression-bonded by the ACF 44.
[0051]
【The invention's effect】
According to the present invention, it is possible to provide an electronic module with high reliability of electrical connection that can cope with high density.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an outline of an embodiment of the present invention.
2A is a partial plan view showing a 2A region of the liquid crystal module shown in FIG. 1, and FIG. 2B is a view of the liquid crystal module shown in FIG.
FIG. 3 is a cross-sectional view corresponding to 3A-3A ′ of the printed wiring board shown in FIG.
FIG. 4 is a view of the active matrix substrate shown in FIG. 1 as viewed from the direction of arrow 4A.
5A is a cross-sectional view corresponding to 5A-5A ′ of the liquid crystal module shown in FIG. 1, FIG. 5B is a cross-sectional view corresponding to 5B-5B ′, and FIG. 5D is a diagram of the 5C portion viewed from the normal direction of the main surface of the display panel, and FIG. 5D is a diagram of the 5D portion viewed from the normal direction of the main surface of the display panel.
FIG. 6 is a partial schematic view of a liquid crystal display device disclosed in Patent Document 1.
FIG. 7 is a partial schematic diagram of a liquid crystal display device disclosed in Patent Document 2.
[Explanation of symbols]
2 Display panel 4 Active matrix substrate 6 Counter substrate 8 TCP
8A TCP
8B TCP
9 Drive circuit 10 Printed wiring board 12 Terminal 12A Terminal 12B Terminal 14 Superposition area 16 Through hole 18 Insulating layer 20 Copper foil layer 22 Main surface 24 Back surface 28 Signal line 28A Board terminal 28B Board terminal 38 Main surface 40 End surface 42 Back surface 44 Output terminal 46 input terminal 48 output terminal

Claims (9)

An electronic circuit having a plurality of circuit elements and a plurality of signal lines connected to each of the plurality of circuit elements on a main surface, and having a plurality of substrate terminals connected to each of the plurality of signal lines. Board and
A first drive circuit board and a second drive circuit board, each having a drive circuit, mounted on the electronic circuit board adjacent to each other;
An electronic module comprising: a wiring board for supplying a predetermined signal to each of the first drive circuit board and the second drive circuit board;
The wiring board has a plurality of terminals on each of a main surface facing the same direction as the main surface of the electronic circuit board, and a back surface facing the main surface,
The first drive circuit board is electrically connected to the plurality of terminals on the main surface of the wiring board,
The electronic module, wherein the second drive circuit board is electrically connected to the plurality of terminals on the back surface of the wiring board. The plurality of substrate terminals are formed on the back surface opposite to the main surface and the main surface of the electronic circuit board,
The first drive circuit board and the second drive circuit board each have a plurality of input terminals and a plurality of output terminals on each main surface,
The plurality of input terminals and the plurality of output terminals of the first drive circuit board are, respectively, the plurality of terminals on the main surface of the wiring board and the plurality of substrate terminals on the main surface of the electronic circuit board. Electrically connected,
The plurality of input terminals and the plurality of output terminals of the second drive circuit board are electrically connected to the plurality of terminals on the back side of the wiring board and the plurality of board terminals on the back side of the electronic circuit board, respectively. The electronic module according to claim 1, wherein the electronic module is connected to the electronic module. The electronic module according to claim 1, wherein the main surface of the first drive circuit board and the main surface of the second drive circuit board are arranged so as to face in opposite directions. The plurality of substrate terminals formed on the back surface of the electronic circuit board extend from the main surface of the electronic circuit board to the back surface via an end surface existing between the main surface and the back surface. The electronic module according to claim 2, wherein the electronic module is connected to the plurality of signal lines. The wiring board includes the plurality of terminals connected to the plurality of input terminals of the first drive circuit board in a first terminal area, and is connected to the plurality of input terminals of the second drive circuit board. A plurality of terminals in a second terminal area.
The at least part of the first terminal region and at least a part of the second terminal region overlap with each other when viewed from a normal direction of the main surface of the wiring substrate. An electronic module according to claim 1. Between the plurality of input terminals of the first drive circuit board and the plurality of terminals of the wiring board, between the plurality of input terminals of the second drive circuit board and the plurality of terminals of the wiring board, The plurality of output terminals of the first drive circuit board and the plurality of board terminals of the electronic circuit board, and the plurality of output terminals of the second drive circuit board and the plurality of boards of the electronic circuit board The electronic module according to claim 2, wherein an anisotropic conductive layer is disposed between the terminal and the terminal. The electronic module according to claim 1, wherein the first driving circuit board and the second driving circuit board are substantially the same. The electronic module according to any one of claims 1 to 7, wherein the wiring board is PWB. A liquid crystal display device comprising the electronic module according to claim 1.

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