JP2008112070A - Inter-substrate connection structure, inter-substrate connection method, display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting structure between boards resistant, to breaking of wiring on a flexible wiring board and resistant to short-circuiting across an outer frame or the like. <P>SOLUTION: The connecting structure between boards makes electrical connection between a first board 1b and a second board 2 arranged in a case 9; the first board 1b is connected to the second board 2 via a flexible wiring board 30; while the first board 1b is arranged on a top face of the case 9, the second board 2 is arranged on the side face of the case 9; the flexible wiring board 30 is connected to the first board 1b on the top face of the case 9 and is curved along the side face of the case 9 from the top face of the case 9, and is connected to the second board 2 on the side face of the case 9; and the structure is such that the side face of the case 9 is provided with an accommodating concave part 12, formed concave from the side face of the case 9, and the second board 2 is accommodated in the accommodating concave part 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inter-substrate connection structure, an inter-substrate connection method, and a display device such as a liquid crystal display device or an EL display device.

2. Description of the Related Art Conventionally, there is known a display device having a configuration in which a control board is connected to a display panel such as a liquid crystal panel and various control signals are supplied to the display panel through the control board. In such a display device, for example, Patent Document 1 discloses a technique for connecting a display panel and a control board via a flexible wiring board in order to reduce the size of the apparatus.
JP 2004-117659 A

  Patent Document 1 discloses a liquid crystal display device intended to prevent inadvertent damage to a flexible wiring board connected to a liquid crystal panel. Specifically, a sheet metal case having a bottom wall and a side wall bent from an edge of the bottom wall after being pressed, a resin frame disposed along an inner surface of the side wall of the sheet metal case, and the resin frame A liquid crystal panel having an edge supported by the liquid crystal panel, a printed circuit board disposed on the outer surface of the bottom wall of the sheet metal case facing the liquid crystal panel, and the liquid crystal panel and the printed circuit board connected to each other, In a liquid crystal display device including a flexible wiring board that protrudes laterally from the side wall of the sheet metal case and that protrudes laterally, the resin frame has a protruding portion that protrudes laterally from the outer surface of the side wall of the sheet metal case. A technique characterized by the above is disclosed.

  However, in the technique according to Patent Document 1, since the corners of the printed circuit board rub against the flexible circuit board, there may be a problem that the wiring on the flexible wiring board is disconnected. In addition, since the flexible wiring board is lifted from the sheet metal case by the thickness of the printed circuit board, the flexible wiring board can easily come into contact with the outer frame (bezel) of the liquid crystal panel, and the bezel and wiring that are usually made of sheet metal or the like A short circuit may occur between the two.

  The present invention has been made to solve the above-described problems, and when connecting between substrates via a flexible wiring board, the wiring on the flexible wiring board is not easily disconnected, and an outer frame or the like is used. It is an object of the present invention to provide a board-to-board connection structure and a board-to-board connection method that are unlikely to cause a short circuit. Furthermore, the present invention provides a display device having a configuration in which a display panel and a control board are connected using a flexible wiring board, and the wiring on the flexible wiring board is not easily disconnected, and is short-circuited with the outer frame of the display panel. The object is to provide a configuration in which the occurrence of the problem is difficult to occur.

  In order to solve the above-described problems, an inter-board connection structure according to the present invention is an inter-board connection structure that electrically connects a first board and a second board disposed in a housing, the first board and The second substrate is connected to the second substrate via a flexible wiring substrate, the first substrate is disposed on the upper surface of the housing, and the second substrate is disposed on a side surface of the housing. The upper surface of the housing is connected to the first substrate, is curved along the housing side surface from the upper surface of the housing, is connected to the second substrate on the side surface of the housing, and is connected to the side surface of the housing. Is provided with an accommodation recess formed to be recessed from the side of the housing, and the second substrate is accommodated in the accommodation recess.

  According to such an inter-substrate connection structure, the second substrate is accommodated in the accommodating recess formed on the side surface of the housing, so that the influence of the thickness of the second substrate can be eliminated. The flexible wiring board rises due to the disconnection of the wiring at the portion and the thickness of the second substrate, and for example, the problem that the wiring is short-circuited with the outer frame or the like hardly occurs. That is, by housing the second substrate in the housing recess formed on the side surface of the housing, the thickness of the portion of the second substrate protruding from the housing side surface is reduced. For example, the depth of the housing recess is set to the second substrate. If the thickness is the same, the side surface of the housing and the second substrate are flush with each other, and the second substrate does not protrude from the side surface. As a result, the corner portion of the second substrate does not protrude, and the flexible wiring board connected to the second substrate hits the corner portion, so that the trouble that the wiring on the flexible wiring substrate is disconnected hardly occurs. . Similarly, since the protrusion of the second substrate is reduced or eliminated, the floating of the flexible wiring substrate is reduced or prevented, and as a result, a problem of short-circuiting with the outer frame or the like hardly occurs.

  Note that the second substrate can be accommodated in the accommodating recess, and for example, the second substrate can be configured not to be fixed to the housing (that is, the second substrate can be moved in the accommodating recess). In this case, even if the second substrate expands due to the influence of heat or the like and warps and deforms, a load is not applied to the connection portion with the flexible wiring substrate, and the occurrence of peeling or disconnection is prevented or suppressed. It becomes possible.

In the inter-board connection structure of the present invention, the first substrate is a substrate provided in an electronic device disposed on the housing, and the second substrate is a control substrate that controls the electronic device. There can be.
In this case, it is possible to realize an electrical connection between the electronic device and the control board that is unlikely to cause a disconnection or a short circuit, so that the operation reliability of the electronic device can be improved.

A conductive film may be disposed on the second substrate, and the conductive film may be connected to the flexible wiring substrate via an anisotropic conductive adhesive layer.
In this case, since the second substrate is accommodated in the accommodating recess, it is difficult for the flexible wiring substrate to be subjected to useless force, and problems such as peeling between the flexible wiring substrate and the anisotropic conductive adhesive layer are unlikely to occur. Become. In particular, when the second substrate is accommodated in the accommodating recess and the side surface of the housing and the second substrate surface are flush with each other, the effect of suppressing peeling becomes significant.

The first substrate and the second substrate may be rigid substrates.
In this way, when connecting a flexible wiring board to a rigid board, if the corner of the rigid board protrudes, the flexible wiring board may hit the corner and cause disconnection, but in the present invention Since the rigid substrate is accommodated in the accommodating recess to prevent or reduce the protrusion of the substrate, the disconnection or the like hardly occurs.

The casing may be made of a resin material.
In this case, the housing recess according to the present invention can be easily formed at the time of resin molding, which can contribute to cost reduction and can also prevent a short circuit to the housing.

The housing recess may have a depth equal to or greater than the plate thickness of the second substrate.
In this case, the protrusion (protrusion) of the second substrate can be surely eliminated, and as a result, the above-described disconnection or short circuit can be further prevented or suppressed.

In addition, by making the depth of the housing recess and the thickness of the second substrate the same, the side surface of the housing and the plate surface of the second substrate are in a state where the second substrate is housed in the housing recess. Can be flush.
Also in this case, the protrusion (projection) of the second substrate can be surely eliminated, and as a result, the above-described disconnection and short circuit can be further prevented or suppressed, and the flexible wiring substrate and the second substrate can be prevented. In addition, for example, when a flexible wiring board is connected via an anisotropic conductive adhesive layer, peeling does not easily occur.

The casing is provided with a substrate drop prevention means that prevents or suppresses the second substrate from dropping from the receiving recess when the second recess is received in the receiving recess. Can do.
In this case, it is possible to prevent or suppress the second substrate from being removed from the housing recess, so that the above-described disconnection or short circuit is less likely to occur.
In addition, as a board | substrate drop-off suppression means, the suppression member (projection piece) provided in the entrance of the accommodation recessed part can be illustrated, and specifically, the 2nd accommodated in the inside in the form which shields the entrance of an accommodation recessed part a little. A holding member (projection piece) or the like that suppresses a part of the substrate is preferable.

  Next, in order to solve the above-mentioned problem, the inter-board connection method of the present invention is an inter-board connection method for electrically connecting a first substrate and a second substrate disposed in a housing, wherein the housing A step of disposing a first substrate on an upper surface; and a second substrate disposing step of disposing a second substrate electrically connected to the first substrate via a flexible wiring substrate on a side surface of the housing. And the second substrate disposing step is performed while the flexible wiring substrate is curved from the upper surface of the housing along the side surface of the housing, and is further recessed in the side surface of the housing. The second substrate is accommodated in the accommodated recessed portion.

  According to such an inter-substrate connection method, the influence of the thickness of the second substrate can be eliminated by accommodating the second substrate in the accommodating recess formed on the side surface of the housing. The flexible wiring board rises due to the disconnection of the wiring at the portion and the thickness of the second substrate, and for example, the problem that the wiring is short-circuited with the outer frame or the like hardly occurs. That is, by housing the second substrate in the housing recess formed on the side surface of the housing, the thickness of the portion of the second substrate protruding from the housing side surface is reduced. For example, the depth of the housing recess is set to the second substrate. If the thickness is the same, the side surface of the housing and the second substrate are flush with each other, and the second substrate does not protrude from the side surface. As a result, the corner portion of the second substrate does not protrude, and the flexible wiring board connected to the second substrate hits the corner portion, so that the trouble that the wiring on the flexible wiring substrate is disconnected hardly occurs. . Similarly, since the protrusion of the second substrate is reduced or eliminated, the floating of the flexible wiring substrate is reduced or prevented, and as a result, a problem of short-circuiting with the outer frame or the like hardly occurs.

  Next, in order to solve the above-described problem, a display device of the present invention is a display device including a display panel and a control board that controls the display panel, and a housing for mounting the display panel And an external connection board that is provided in the display panel and electrically connects the display panel and the control board, and a flexible wiring board that electrically connects the external connection board and the control board. The flexible wiring board is connected to the external connection board on the upper surface of the casing, is curved along the side of the casing from the upper surface of the casing, and is connected to the control board on the side of the casing. The housing side surface is provided with a housing recess formed to be recessed from the housing side surface, and the control board is housed in the housing recess.

  According to such a display device, by accommodating the control board in the housing recess formed on the side surface of the housing, the influence of the thickness of the control board can be eliminated, and the disconnection of the wiring at the corner of the control board In addition, the flexible wiring board floats due to the influence of the thickness of the control board, and it is difficult to cause a problem that the wiring is short-circuited with an outer frame or the like that accommodates the display panel, for example. That is, by accommodating the control board in the housing recess formed on the side surface of the housing, the thickness of the control board protruding from the side surface of the housing is reduced. For example, the depth of the housing recess is made the same as the thickness of the control board. By doing so, the casing side surface and the control board are flush with each other, and the control board does not protrude from the side surface. As a result, the corner portion of the control board does not protrude, and the flexible wiring board connected to the control board hits the corner portion, so that the problem that the wiring on the flexible wiring board is disconnected hardly occurs. Similarly, the protrusion of the control board is reduced or eliminated, so that the floating of the flexible wiring board is prevented or reduced, and as a result, a short circuit with the outer frame or the like hardly occurs. As a result, the operational reliability of the display device can be increased.

  In addition, it can be set as the structure which accommodates a control board in an accommodation recessed part, for example, the said control board is not fixed with respect to a housing | casing (namely, the structure which can move a control board within an accommodation recessed part). In this case, even if the control board expands due to the influence of heat or the like and warps and deforms, no load is applied to the connection part with the flexible wiring board, and the occurrence of peeling or disconnection is prevented or suppressed. Is possible.

In the display device of the present invention, a conductive film may be provided on the control substrate, and the conductive film may be connected to the flexible wiring substrate via an anisotropic conductive adhesive layer.
In this case, since the control board is housed in the housing recess, useless force is hardly applied to the flexible wiring board, and problems such as peeling between the flexible wiring board and the anisotropic conductive adhesive layer hardly occur. . In particular, when the control board is housed in the housing recess and the housing side surface and the control board surface are flush with each other, the effect of suppressing peeling becomes significant.

The display panel may be a liquid crystal panel, and a backlight may be disposed on the opposite side of the housing from the side on which the liquid crystal panel is disposed.
In this case, the display device is a liquid crystal device, and the backlight and the liquid crystal panel can be suitably held or protected integrally.

The external connection board and the control board may be rigid boards.
In this way, when connecting a flexible wiring board to a rigid board, if the corner of the rigid board protrudes, the flexible wiring board may hit the corner and cause disconnection, but in the present invention Since the rigid substrate is accommodated in the accommodating recess to prevent or reduce the protrusion of the substrate, the disconnection or the like hardly occurs.

The casing may be made of a resin material.
In this case, the housing recess according to the present invention can be easily formed at the time of resin molding, which can contribute to cost reduction and can also prevent a short circuit to the housing.

The housing recess may have a depth equal to or greater than the plate thickness of the control board.
In this case, the protrusion (protrusion) of the control board can be surely eliminated, and as a result, the occurrence of the above-described disconnection or short circuit can be further prevented or suppressed.

Further, by making the depth of the housing recess and the thickness of the control board the same, the side surface of the housing and the plate surface of the control board are flush with each other in a state where the control board is housed in the housing recess. can do.
Also in this case, the protrusion (projection) of the control board can be surely eliminated, and as a result, the occurrence of the disconnection or short circuit described above can be further prevented or suppressed, and the flexible wiring board and the control board can be prevented. Connection stability can also be imparted. For example, when a flexible wiring board is connected via an anisotropic conductive adhesive layer, peeling does not easily occur.

The housing may be provided with a substrate drop prevention means that prevents or suppresses the control board from falling out of the housing recess while the control board is housed in the housing recess. .
In this case, it is possible to prevent or suppress the control board from falling out of the housing recess, so that the above-described disconnection or short circuit is less likely to occur.
In addition, as a board | substrate fall-off suppression means, the control member (projection piece) provided in the entrance of the accommodation recessed part can be illustrated, and specifically, the control board accommodated in the inside in the form which shields the entrance of the accommodation recessed part a little It is preferable to use a restraining member (projection piece) or the like that suppresses a part of the surface.

  The display panel includes pixels arranged in a matrix, source wirings for supplying data signals to the pixels, and gate wirings for supplying scanning signals. It may be a source circuit board that controls output of a signal to the source wiring. Alternatively, the control board may be a gate circuit board that controls the output of signals to the gate wiring. By accommodating such a circuit board in the accommodation recess according to the present invention and connecting it to the flexible wiring board, the connection stability can be improved, and thus the reliability of the display device can be improved. It becomes.

  According to the inter-substrate connection structure and inter-substrate connection method of the present invention, it is difficult to cause disconnection or short circuit, and stable inter-substrate connection can be realized. In addition, according to the display device of the present invention, disconnection, short circuit, and the like are unlikely to occur, stable board-to-board connection can be realized, and as a result, display with high reliability can be realized.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a plan view showing a schematic configuration of a liquid crystal panel, FIG. 2 is an exploded perspective view of a liquid crystal display device (display device) provided with the liquid crystal panel, and FIG. 3 shows a configuration of an inter-substrate connection structure provided in the liquid crystal display device. 4 is a side view showing the configuration of the inter-substrate connection structure, FIG. 5 is a side view showing the configuration of the inter-substrate connection structure according to the comparative example, and FIG. 6 is a diagram showing the connection between the flexible wiring board and the printed wiring board. It is sectional drawing which expands and shows the connection aspect between them.
Note that in this embodiment, a liquid crystal display device is described as a display device; however, the present invention is not limited to this, and other display devices such as an electroluminescence display device (EL display device) may be used.

  The liquid crystal display device 10 according to the present embodiment includes a liquid crystal panel 1 as a display panel including an upper glass substrate 1a and a lower glass substrate 1b sandwiched between deflection plates (not shown). A liquid crystal layer (not shown) is sandwiched between the upper glass substrate 1a and the lower glass substrate 1b together with panel electrode terminals 6 as external connection terminals. The lower glass substrate 1b is an element substrate, and pixels (not shown) having TFT elements are arranged in a matrix. The upper glass substrate 1a is a counter substrate, and color filters (not shown) corresponding to the pixels of the lower glass substrate 1b are arranged.

  Further, source wiring and gate wiring (not shown) formed so as to intersect with each other in a lattice shape are formed on the lower glass substrate 1b, and are connected to TFT elements formed in each pixel. Each wiring extends to the end of the lower glass substrate 1b and is connected to semiconductor elements 3a and 4a as liquid crystal drivers.

  The lower glass substrate 1b is formed longer than the upper glass substrate 1a, and the panel electrode terminal 6 is exposed and extended to the lower glass substrate 1b. The panel electrode terminal 6 is a terminal for applying a voltage for driving the liquid crystal panel 1 to the liquid crystal driving electrode, and a wiring (not shown) is connected to the liquid crystal driving electrode (not shown) in the liquid crystal panel 1. Connected through.

  The liquid crystal display device 10 has a semiconductor device that functions as a liquid crystal driver for driving the liquid crystal panel 1. This semiconductor device is mounted on a flexible wiring substrate 30 on which a Cu (copper) foil pattern 3b (see FIG. 6) as a wiring pattern is formed on the surface of a flexible film substrate 3, and on the surface side of the flexible wiring substrate 30. The semiconductor element 3a functions as a liquid crystal driver integrated circuit (IC). Therefore, this semiconductor device is mounted on COF (Chip On Film). A flexible wiring board mounted with COF like the flexible wiring board 30 is generally called “COF” and is thinner than a flexible wiring board mounted with TCP.

  The Cu (copper) foil pattern 3b of the flexible wiring board 30 has an output outer lead for connecting to the liquid crystal panel 1 at one end, and an input outer lead (for connecting to another circuit board at the other end). Terminal 3d). In this embodiment, the Cu (copper) foil pattern 3b is used as the wiring pattern, but the wiring pattern may be a pattern made of another conductor, for example, aluminum (Al).

  As shown in FIG. 6, the film base 3 of the flexible wiring board 30 is made of a thin film made of a polyimide resin or the like, and has a thickness of 40 μm or less, more preferably 25 μm to 40 μm. It has flexibility.

  A solder resist 3c as an insulating protective layer is laminated on the Cu (copper) foil pattern 3b formed on the surface of the flexible wiring board 30. The solder resist 3c is made of a material such as polyimide, for example, and insulates the Cu (copper) foil pattern 3b from the outside, and protects the Cu (copper) foil pattern 3b from corrosion such as rust generation. And plays a role of improving the bending resistance of the flexible wiring board 30. In particular, the solder resist 3c is formed such that the end portion of the Cu (copper) foil pattern 3b is exposed so that the end portion of the Cu (copper) foil pattern 3b can be used as an electrode.

  The solder resist 3c is provided with an opening (not shown) for connection with the semiconductor element (driver chip) 3a. The Cu (copper) foil pattern 3b exposed from the opening serves as an inner lead (not shown) for connection to the driver chip 3a.

  As described above, one end of the flexible wiring board 30 having the Cu (copper) foil pattern 3b on the surface extends to the liquid crystal panel 1 side, and a pattern terminal as a terminal portion formed at the end of the Cu (copper) foil pattern 3b. The portions (not shown) are connected by an anisotropic conductive adhesive (ACF) at the end of the panel electrode terminal 6 formed on the lower glass substrate (external connection substrate) 1b of the liquid crystal panel 1. ing. Thus, the semiconductor element 3a of the semiconductor device according to the present embodiment functions as a liquid crystal driver integrated circuit (IC) and functions as a liquid crystal driver that drives the liquid crystal panel 1.

  On this semiconductor element 3 a, a protruding electrode (not shown) made of Au having a height of about 10 μm is formed on the surface connected to the flexible substrate 30 by plating. In this semiconductor element 3a, all the protruding electrodes and the flexible substrate 30 are connected together by face down ILB (Inner Lead Bonding). This connection is performed by thermocompression bonding, and is performed by a eutectic of Au, which is a protruding electrode material, and Sn electrolessly plated on the surface of the flexible substrate 30.

  On the other hand, at the end of the flexible wiring substrate 30 opposite to the liquid crystal panel (display panel) 1, the pattern terminal portion 3d formed at the end of the Cu (copper) foil pattern 3b is an anisotropic conductive adhesive layer. It is connected to the pattern terminal portion (first connection terminal) 2d of the printed wiring board (control board) 2 via the (ACF) 5 and obtains electric power etc. by a power supply circuit or the like. That is, inter-substrate connection is performed through the anisotropic conductive adhesive layer 5 in a state where the pattern terminal portion 3 d of the flexible wiring board 30 and the pattern terminal portion 2 d of the printed wiring board 2 face each other.

  The printed wiring board 2 is composed of a rigid board, which is a source circuit board in this embodiment, and is a circuit board (control board) that controls output of signals to source wiring (not shown) formed on the liquid crystal panel 1. It is. In this printed wiring board 2, a Cu (copper) foil pattern 2a is formed on a rigid base 2c, and a solder resist 2b is further formed on the Cu (copper) foil pattern 2a.

  The anisotropic conductive adhesive layer 5 is obtained by dispersing conductive particles in an insulating adhesive. The anisotropic conductive adhesive layer 5 serves to join the pattern terminal portion 2d and the pattern terminal portion 3d with an adhesive, and also serves to electrically connect the pattern terminal portion 2d and the pattern terminal portion 3d with conductive particles. To fulfill.

  The adhesive is preferably a thermosetting adhesive such as an epoxy resin or an acrylic resin because it can be joined by thermocompression bonding. The conductive particles include metal particles such as Ni, metal particles obtained by performing Au plating on metal particles such as Ni, carbon particles, and thermoplastic resin particles (plastic particles) by Au plating or Au / Ni plating (on the ground). Plated thermoplastic resin particles plated with Au after forming an Ni layer), transparent conductive particles such as ITO (Indium Tin Oxide), and conductive particle composites in which metal particles such as Ni are mixed with polyurethane Plastic or the like can be used. Of these, plated thermoplastic resin particles are particularly preferable as the conductive particles. The particle size of the conductive particles is preferably in the range of 3 μm to 12 μm. In the case of plated thermoplastic resin particles, it is preferable that the thermoplastic resin particles having a particle diameter of 3 μm to 5 μm are plated. Furthermore, as the anisotropic conductive adhesive layer 5, there are a film type and a paste type, but the film type is more preferable because it is easy to handle and the thickness can be adjusted accurately.

  The solder resist 2b is an insulating protective film made of a resin material. Here, the solder resist 2b is composed of an epoxy resin-based heat-resistant coating material. Examples of film forming methods for the solder resist 2b include a screen printing method and a photographic printing method. Can be adopted.

  On the other hand, as shown in FIG. 2, the liquid crystal display device 10 includes the liquid crystal panel 1, a backlight 8 that irradiates the liquid crystal panel 1 with light from the back side, and the liquid crystal panel 1 and the backlight 8. And a bezel 11 for protecting or fixing the liquid crystal panel 1 and the backlight 8 integrated by the backlight chassis 9. The backlight 8 includes a plurality of fluorescent lamps 8a arranged in parallel on a plate-shaped metal member 8b. The backlight chassis 9 is formed by molding a resin material, and the bezel 11 is formed from a frame-shaped metal member. It will be.

  Further, the backlight chassis 9 is formed with a counterbore portion (accommodation recess) 12 for accommodating the printed wiring board 2, and the counterbore portion 12 is a suppressing member that prevents or suppresses dropping of the printed wiring board 2 accommodated therein. (Substrate drop prevention means) 13 is formed. That is, the printed wiring board 2 connected to the liquid crystal panel 1 shown in FIG. 1 is formed in the counterbore portion 12 recessed in the side surface of the backlight chassis 9 in the liquid crystal display device 10 as shown in FIGS. It is accommodated and is prevented from falling off the counterbore portion 12 by the holding member 13.

  Here, the liquid crystal panel (electronic device, display panel) 1 is installed on the upper surface 9 a (panel receiving portion or panel receiving surface) of the backlight chassis 9 via a cushion rubber 14, and a rigid lower glass on the cushion rubber 14. A substrate (first substrate, external connection substrate) 1b is arranged. On the other hand, the flexible wiring board 30 is connected to the lower glass substrate 1b as described above, and a printed wiring board (control board) disposed on the counterbore portion 12 of the side surface 9b of the backlight chassis 9 through the flexible wiring board 30. , Circuit board) 2 and the lower glass substrate 1b.

  The flexible wiring board 30 is connected to the lower glass substrate 1b on the upper surface 9a of the backlight chassis 9, is curved from the upper surface 9a to the side surface 9b, and is connected to the printed wiring board 2 on the side surface 9b. And the printed wiring board 2 is accommodated in the counterbore part 12 formed in the side surface 9b of the backlight chassis 9, and the protrusion from the side surface 9b of the printed wiring board 2 is eliminated by this. Specifically, by accommodating the printed wiring board 2 in the counterbore part 12, the protrusion of the printed wiring board 2 from the side surface 9b of the backlight chassis is eliminated as shown in FIG. By forming the counterbore part 12 at a depth equal to or greater than the thickness, the protrusion is eliminated. More preferably, the counterbore part 12 is formed at the same depth as the thickness of the printed wiring board 2, so that the printed wiring board 2 is formed. In the counterbore part 12, the board surface of the printed wiring board 2 and the side surface 9 b of the backlight chassis 9 can be flush with each other.

  Further, the holding member 13 provided on the counterbore portion 12 of the backlight chassis 9 is configured as a protruding piece that protrudes from the side surface of the chassis 9 and covers a part of the counterbore portion 12. Specifically, a main body portion 13a that protrudes upward from the lower end portion 12a of the counterbore portion 12, a protrusion that protrudes from the main body portion 13a to the printed wiring board 2 side, is in contact with the printed wiring board 2, and the substrate 2 swings. And a plurality of protrusions 13b are formed along the longitudinal direction of the counterbore part 12 (that is, the longitudinal direction of the printed wiring board 2). The counterbore part 12 and the holding member 13 of the backlight chassis 9 are molded when the chassis made of a resin material is manufactured.

By forming the counterbore portion 12 as described above, the liquid crystal display device 10 of the present embodiment has the following operational effects.
That is, by accommodating the printed wiring board 2 in the counterbore portion 12 formed on the side surface 9b of the backlight chassis 9, the influence of the thickness of the printed wiring board 2 can be eliminated, and it is made of a rigid base material. The flexible wiring board 30 is lifted due to the disconnection of the wiring at the corner of the printed wiring board 2 or the thickness of the printed wiring board 2, and the wiring is connected to the bezel 11 (see FIG. 2) that accommodates the liquid crystal panel 1. It is difficult for a short circuit to occur.

  That is, when the counterbore part 12 is not provided, the printed wiring board 2 makes a business trip from the side surface 9b of the backlight chassis 9 as shown in FIG. In this case, the flexible wiring board 30 comes into contact with the corner of the printed wiring board 2, and the copper foil pattern 3 b on the flexible wiring board 30 is disconnected due to the contact, or the flexible wiring board 30 is lifted and comes into contact with the bezel 11. In some cases, a short circuit may occur with the bezel 11. However, the counterbore portion 12 is provided as in the present embodiment to eliminate the influence of the thickness of the printed wiring board 2 so that the corner of the printed wiring board 2 contacts the flexible wiring board 30 as described above. In addition, since the floating of the flexible wiring board 30 can also be eliminated, it is possible to prevent or suppress the occurrence of problems such as disconnection or short circuit.

  In particular, since the depth of the counterbore portion 12 is the same as the thickness of the printed wiring board 2, the side surface 9 b of the backlight chassis 9 and the plate surface of the printed wiring board 2 are flush with each other. The wiring board 2 is configured not to protrude reliably. As a result, the corners of the printed wiring board 2 do not protrude, and the flexible wiring board 30 connected to the printed wiring board 2 hits the corners, so that the problem that the wiring on the flexible wiring board 30 is disconnected is less likely to occur. As a result, the operation reliability of the liquid crystal display device 10 becomes very high.

  In the present embodiment, the copper foil pattern (conductive film) 2 a of the printed wiring board 2 is connected to the flexible wiring board 30 via the anisotropic conductive adhesive layer 5. In the present embodiment in which the printed wiring board 2 is accommodated in the counterbore part 12, it is difficult to apply a useless force to the flexible wiring board 30. In the configuration using the anisotropic conductive adhesive layer 5 as described above, the flexible wiring board 30 is used. And the anisotropic conductive adhesive layer 5 are less prone to problems such as peeling.

In order to realize the connection structure between the substrates, the following method (inter-substrate connection method) is used.
First, the backlight chassis 9 in which the counterbore 12 is recessed on the side surface is obtained by molding. Next, the backlight 8 is assembled to the backlight chassis 9, and the backlight chassis 9 and the liquid crystal panel 1 are integrated. At this time, the lower glass substrate 1b of the liquid crystal panel 1 is disposed on the upper surface 9a of the backlight chassis 9, while the flexible wiring substrate 30 connected to the lower glass substrate 1b is moved from the upper surface 9a of the backlight chassis 9 to the side surface 9b. The printed wiring board 2 connected to the other end of the flexible wiring board 30 is accommodated in the counterbore part 12 of the backlight chassis 9 while being bent along the line. Thereafter, by integrally protecting the liquid crystal panel 1 and the outside of the backlight chassis 9 with the bezel 11, the above-described inter-board connection structure can be realized.

Although the embodiment according to the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.
For example, in the above-described embodiment, the inter-board connection structure between the printed wiring board 2 as the source wiring board and the flexible wiring board 30 is shown as an example. However, for example, the printed wiring board 7 as the gate wiring board of the liquid crystal display device 10. The inter-substrate connection structure can also be adopted on the side (see FIG. 1). Specifically, a flexible substrate 40 including a semiconductor element 4a on a flexible film base 4 is connected to a gate wiring substrate (printed wiring substrate) 7, and the gate wiring substrate 7 is connected to a backlight chassis. Nine counterbore portions 12 can be accommodated.

  In the above-described embodiment, the liquid crystal display device is shown as an example of the display device. However, the display device is not particularly limited as long as it is a display device that performs pixel display and requires connection between substrates. For example, EL display devices, plasma light emitting display devices, electrophoretic display devices, and the like can be exemplified.

The top view which shows schematic structure of a liquid crystal panel. The disassembled perspective view of a liquid crystal display device provided with a liquid crystal panel. The expansion perspective view which shows the structure of the connection structure between board | substrates with which a liquid crystal display device is provided. The side view which shows the structure of the connection structure between board | substrates with which a liquid crystal display device is provided. The side view which shows the structure of the connection structure between the boards which concerns on a comparative example. Sectional drawing which expands and shows the connection aspect between a flexible wiring board and a printed wiring board.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal panel (display panel, electronic device), 1b ... Lower glass board | substrate (1st board | substrate, external connection board), 2 ... Printed wiring board (2nd board | substrate, control board), 9 ... Backlight chassis (housing | casing) DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display device (display apparatus), 12 ... Housing recessed part, 30 ... Flexible wiring board

Claims (19)

A board-to-board connection structure for electrically connecting a first board and a second board disposed in a housing,
The first substrate and the second substrate are connected via a flexible wiring substrate, the first substrate is disposed on the upper surface of the housing, and the second substrate is disposed on a side surface of the housing.
The flexible wiring board is connected to the first substrate on the upper surface of the housing, is curved along the housing side surface from the upper surface of the housing, is connected to the second substrate on the housing side surface, and
An inter-substrate connection structure, wherein a housing recess is formed on the side of the housing so as to be recessed from the side of the housing, and the second substrate is received in the housing recess.   The first substrate is a substrate provided in an electronic device disposed on the housing, and the second substrate is a control substrate for controlling the electronic device. The board-to-board connection structure described.   The copper wiring is disposed on the second substrate, and the copper wiring is connected to the flexible wiring substrate via an anisotropic conductive adhesive layer. Board-to-board connection structure.   4. The inter-board connection structure according to claim 1, wherein the first substrate and the second substrate are rigid substrates. 5.   The inter-board connection structure according to claim 1, wherein the casing is made of a resin material.   6. The inter-substrate connection structure according to claim 1, wherein the accommodating recess has a depth equal to or greater than a plate thickness of the second substrate.   The side surface of the housing and the plate surface of the second substrate are flush with each other in a state in which the second substrate is accommodated in the accommodating recess. The board-to-board connection structure described in 1.   The housing is provided with a substrate drop prevention means that prevents or suppresses the second substrate from dropping out of the housing recess in a state where the second substrate is housed in the housing recess. The inter-board connection structure according to any one of claims 1 to 7. An inter-board connection method for electrically connecting a first board and a second board disposed in a housing,
Disposing a first substrate on the upper surface of the housing;
A second substrate disposing step of disposing a second substrate electrically connected to the first substrate via a flexible wiring substrate on the side surface of the housing;
The second substrate disposing step is performed while the flexible wiring substrate is curved from the upper surface of the casing along the side surface of the casing, and is further recessed in the side surface of the casing with respect to the side surface of the casing. A board-to-board connection method comprising: housing the second board in a housing recess. A display device comprising a display panel and a control board for controlling the display panel,
A housing for mounting the display panel;
Provided in the display panel, an external connection substrate for electrical connection between the display panel and the control substrate,
A flexible wiring board that electrically connects the external connection board and the control board;
The flexible wiring board is connected to the external connection board on the upper surface of the casing, is curved along the side of the casing from the upper surface of the casing, is connected to the control board on the side of the casing,
The display device is characterized in that a housing recess is formed on the side of the housing so as to be recessed from the side of the housing, and the control board is housed in the housing recess.   The display device according to claim 10, wherein a conductive film is disposed on the control substrate, and the conductive film is connected to the flexible wiring substrate via an anisotropic conductive adhesive layer.   The display device according to claim 10, wherein the display panel is a liquid crystal panel, and a backlight is disposed on a side of the housing opposite to the side on which the liquid crystal panel is disposed. .   The display device according to claim 10, wherein the external connection substrate and the control substrate are rigid substrates.   The display device according to claim 10, wherein the housing is made of a resin material.   The display device according to claim 10, wherein the housing recess has a depth equal to or greater than a plate thickness of the control board.   The side surface of the housing and the plate surface of the control board are flush with each other in a state in which the control board is housed in the housing recess. Display device.   The housing is provided with a substrate drop prevention means for preventing or suppressing the control board from falling out of the housing recess when the control board is housed in the housing recess. Item 17. The display device according to any one of Items 10 to 16. The display panel includes pixels arranged in a matrix, source wiring for supplying a data signal to the pixel, and gate wiring for supplying a scanning signal,
18. The display device according to claim 10, wherein the control board is a source circuit board that controls output of a signal to the source wiring. The display panel includes pixels arranged in a matrix, source wiring for supplying a data signal to the pixel, and gate wiring for supplying a scanning signal,
The display device according to claim 10, wherein the control substrate is a gate circuit substrate that controls output of a signal to the gate wiring.

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