JP3733825B2 - Electro-optical device and electronic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electro-optical device and an electronic apparatus including the electro-optical device, and more particularly to a power feeding structure for an input terminal of the electro-optical device.
[0002]
[Prior art]
In general, in various electro-optical devices such as a liquid crystal device, an electroluminescence (EL) display device, and a plasma display, a predetermined electric field is applied to an electro-optical material arranged along a substrate, and the electro-optical material is used. The optical characteristics are controlled by driving. In this case, an input terminal for directly or indirectly applying an electric field to the electro-optic material is formed on the substrate surface, and various electric signals are input to the input terminal from the outside.
[0003]
Usually, the input terminal is conductively connected to various wiring members (flexible wiring board, TAB board, etc.) through an anisotropic conductive film (ACF) and the like, and is connected to the outside through these wiring members. The However, if it connects in this way, it will become difficult to remove a wiring member, and rework, maintenance, etc. will become impossible. Furthermore, since a heating and pressurizing step for conducting conductive connection via an anisotropic conductive film is required, a method for connecting an input terminal and a wiring member via an elastic connector has been proposed.
[0004]
As an example of an electro-optical device having such a conductive connection method, a configuration example of a conventional liquid crystal display device is shown in FIGS. A liquid crystal display device 10 shown in FIG. 5 is sealed by sandwiching a liquid crystal layer between substrates 11 and 12 made of glass or the like, and polarizing plates 13 and 14 are attached on the outer surfaces of the substrates 11 and 12. 11 is provided with a liquid crystal panel having a COG (chip on glass) structure in which a semiconductor element 15 for driving liquid crystal is mounted on the surface of 11. This liquid crystal panel is installed on a lower case 16 having a light guiding function made of transparent resin or the like, and an upper case 17 made of metal or the like is mounted thereon, and this upper case 17 is used for an electronic device (for example, a mobile phone). It is fixed to the circuit board 1 installed inside by an engaging portion (not shown). A rectangular opening 16 a is formed in the lower case 16, and an elastic connector 18 is introduced into the opening 16 a and is accommodated in a compressed state between the surface of the substrate 11 and the circuit board 1. The elastic connector 18 is configured to be in conductive contact with an input terminal (not shown) formed on the surface of the panel substrate 11 and a board-side terminal 1 a formed on the circuit board 1. The circuit board 1 is mounted with a light emitting element 1b such as a light emitting diode (LED), and the light emitted from the light emitting element 1b illuminates the liquid crystal panel uniformly from below by the light guide plate function of the lower case 16. It is configured.
[0005]
A liquid crystal display device 20 shown in FIG. 6 includes a liquid crystal panel including substrates 21 and 22, polarizing plates 23 and 24, and a semiconductor element 25 between the lower case 26 and the upper case 27 having a light guiding function. Is housed in. An input terminal (not shown) is formed on the surface of the substrate 21 in the liquid crystal panel, and the input terminal of the flexible wiring substrate 29 arranged so as to be led out from the inside of the upper case 27 through the elastic connector 28. Conductive connection is made to a connection terminal (not shown). The elastic connector 28 receives a clamping pressure from the lower case 26 and the upper case 27 and is sandwiched between the panel substrate 21 and the flexible wiring substrate 29.
[0006]
The above-mentioned elastic connector includes a plurality of fine conductor pieces fixed in an arc shape on the outer peripheral surface of an insulating elastic body such as synthetic rubber, and has a needle-like shape inside the insulating elastic body such as synthetic rubber. Or a conductor embedded with a thin plate-like conductor piece is used. By using such an elastic connector, there is an advantage that the electrical connection work between the liquid crystal panel and the circuit board becomes very easy and the disassembly work can be performed.
[0007]
[Problems to be solved by the invention]
However, in the above conventional liquid crystal display device, an elastic connector is directly pressed against an input terminal made of a transparent conductor such as ITO (indium tin oxide) on a substrate constituting the liquid crystal panel so that an electric signal from the outside is transmitted. Since it is configured to input, the contact resistance between the metal conductor of the terminal piece of the elastic connector and the transparent conductor of the input terminal is large, which may cause a voltage drop at the contact portion. There is a problem that the contact resistance varies greatly depending on the pressure contact state.
[0008]
Therefore, the present invention solves the above problems, and the problem is that in an electro-optical device, the state of conductive connection to an input terminal using an elastic connector can be stabilized and the resistance of the connection portion can be reduced. To provide a structure.
[0009]
[Means for Solving the Problems]
Electro-optical device of the present invention in order to solve the above problems, an electro-optic material is disposed on the substrate, electro-optics a plurality of input terminals and a drive circuit for driving the electro-optical material provided on the base plate The apparatus has a flexible substrate in which a plurality of connection terminal portions are arranged on both surfaces of an insulating support, and the connection terminal portion on one surface of the flexible substrate is conductively connected to the input terminal. An elastic connector is connected to the connection terminal portion on the other surface of the flexible substrate, and the elastic connector is pressed against the input terminal via the flexible substrate .
[0010]
According to the present invention, since the flexible board is fixed on the input terminal and the elastic connector is pressed against the flexible board, the connection of the flexible board can be selected more freely than the input terminal. Since the terminal portion and the terminal of the elastic connector are in contact with each other, the contact resistance can be reduced and the contact resistance can be stabilized. In addition, since the insulating support of the flexible substrate has flexibility, it is possible to increase the compression margin at the contact portion between the flexible substrate and the elastic connector, so that the contact area of the contact portion is increased. In addition, the contact state can be stabilized.
[0011]
In the present invention, the flexible substrate is preferably fixed on the input terminal via an anisotropic conductive film. According to the present invention, the flexible substrate and the input terminal can be securely connected by fixing the flexible substrate on the input terminal via the anisotropic conductive film, and the anisotropic conductive film Due to the flexibility or elasticity, the compression margin at the contact portion between the flexible substrate and the elastic connector can be further increased.
[0012]
In the present invention, the connection terminal portion includes a first conductor pattern portion formed on one surface of the insulating support of the flexible substrate, and a second conductor formed on the other surface of the insulating support. It is preferable that it consists of a body pattern part and the front and back connection part which connects the said 1st conductor pattern part and the said 2nd conductor pattern part.
[0013]
In the present invention, the electro-optic material may be a liquid crystal. A liquid crystal device usually includes a liquid crystal panel in which liquid crystal, which is an electro-optical material, is sandwiched between two substrates.
[0014]
In the present invention, the input terminal may be formed of a transparent conductor. The input terminal is usually formed of a transparent conductor made of the same material as the transparent electrode on the surface of the substrate. When the input terminal is formed of a transparent conductor, since the input terminal is hard, when the elastic connector is directly pressed against the input terminal, the contact area may not be sufficient. Since the elastic connector is brought into contact with a flexible flexible substrate, the compatibility with the terminal portion of the elastic connector can be improved by selecting the material of the connecting terminal portion as appropriate, and flexible. The contact state can be further improved by the flexibility of the substrate.
[0015]
According to another aspect of the invention, an electronic apparatus includes the electro-optical device.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the electro-optical device according to the invention will be described in detail with reference to the accompanying drawings.
[0017]
FIG. 1 is an exploded perspective view showing a relationship between a liquid crystal panel 30 in the liquid crystal display device of the present embodiment and a connection member constituting an electrical connection structure for an input terminal 31d of the liquid crystal panel 30. FIG. In this embodiment, of the two substrates 31 and 32 constituting the liquid crystal panel 30, the substrate 31 includes an overhanging portion 31 a that projects outward from the substrate 32. A plurality of wirings 31b and 31c drawn from a transparent electrode formed in a liquid crystal display region (not shown) are formed on the surface of the protruding portion 31a. These wirings 31b and 31c are electrically and mechanically connected to a semiconductor device 35 (an integrated circuit device in which a liquid crystal driving circuit is formed) mounted on the surface of the overhanging portion 31a. . The semiconductor device 35 is also electrically and mechanically connected to a plurality of input terminals 31d formed at the outer end portion of the overhang portion 31a. The wirings 31b and 31c and the input terminal 31d are both made of ITO (Indium Tin Oxide) like the transparent electrodes (not shown) formed on the surfaces of the substrates 31 and 32 in the liquid crystal display region. Yes.
[0018]
In the present embodiment, a double-sided flexible substrate 37 is fixed to a region where the input terminals 31d are arranged via an anisotropic conductive film 36. Double-sided flexible board 37 includes a flexible substrate 37a made of a soft resin (insulating support), together are supported (supported) by the base substrate 37a, was placed, respectively it on its both sides And a plurality of connection terminal portions 37b. These connection terminal portions 37b are formed so that the number corresponding to the input terminal 31d is the same as that of the input terminal 31d.
[0019]
As the substrate 37a, a film of polyester, polyimide, or the like can be used. On the other hand, the anisotropic conductive film 36 is obtained by, for example, dispersing a large number of conductive particles in a resin base material. The resin base material is softened by pressing the flexible substrate 37 while heating, so that the input terminal 31d. The flexible substrate 37 can be fixed in a state in which the conductive particles are in conductive contact with both the connection terminal 37 b of the flexible substrate 37.
[0020]
FIG. 2 is an enlarged cross-sectional view showing an enlarged structure of a connection portion including the input terminal 31d, the anisotropic conductive film 36, the flexible substrate 37, and the elastic connector 38, and FIG. 3 shows the structure of the flexible substrate 37. It is a fragmentary perspective view. The connection terminal portion 37b of the flexible substrate 37 includes a conductor pattern portion 37b-1 formed on the lower surface of the base body 37a and a conductor pattern portion 37b-2 formed on the upper surface of the base body 37a. These conductor pattern portions 37b-1 and 37b-2 are obtained by coating a conductor pattern made of copper formed on the substrate 37a with gold plating or the like. The conductor pattern portion 37b-1 and the corresponding conductor pattern portion 37b-2 are conductively connected via a connection conductor 37b-3 in a through hole formed in the base body 37a. The connection conductor 37b-3 forms a via hole structure for vertical conduction.
[0021]
FIG. 4 is a longitudinal sectional view showing the structure of another flexible substrate 47 that can be used in place of the flexible substrate 37 shown in the above embodiment. In this flexible substrate 47, conductor pattern portions 47b-1 and 47b-2 formed in the same manner on the front and back sides of the base 47a similar to the above, and these conductor pattern portions 47b-1 and 47b-2, respectively. A connection terminal portion 47b composed of a side conductor portion 47b-3 for conductive connection is provided. The side conductor portion 47b-3 is formed of a conductor pattern that covers the side portion of the base body 47a.
[0022]
The elastic connector 38 includes an insulating elastic body 38a such as synthetic rubber, and a plurality of minute terminal pieces 38b provided in a substantially arc shape (or substantially U shape) along the outer peripheral surface of the insulating elastic body 38a. It consists of The terminal piece 38b is configured to be deformed along with the deformation of the insulating elastic body 38a when compressed in the vertical direction, and is disposed on the upper end surface and the lower end surface of the insulating elastic body 38a. The end portion contacts the connection terminal portion 37b and another external terminal (not shown) (terminal portion on the circuit board, etc.), respectively, so as to transmit an externally supplied electric signal or supply potential to the input terminal 31d. It is configured. In addition to the structure shown in this embodiment, the elastic connector has a structure in which a large number of conductors and conductor pieces are embedded in a synthetic rubber, and an anisotropic material in which a large amount of conductive particles are mixed in the synthetic rubber. Various materials such as a conductive conductive rubber, a terminal piece continuous member attached to an insulating support by bending a plurality of conductor pieces to give elasticity and arranging them in parallel can be used.
[0023]
The structure of this embodiment can be applied as it is to the structure of the liquid crystal display device having the conventional elastic connector shown in FIGS. That is, the conductive connection structure is configured by interposing the anisotropic conductive film 36 and the flexible substrate 37 between the elastic connectors 18 and 28 and the input terminal of the liquid crystal panel. The flexible substrate 37 is previously crimped to the input terminals of the liquid crystal panel in a conductive connection state by a heating and pressing process. Thereafter, the liquid crystal panel is incorporated into the above-described various casings. As a result, the elastic connectors 18 and 28 are conductively connected to the board-side terminals 1a and the flexible wiring board 29 on the circuit board. As a structure of such a conductive connection portion, a liquid crystal panel and a terminal portion of a conductive connection member (flexible wiring board, TAB substrate, etc.) are connected via an elastic connector, a liquid crystal panel and a device are connected via an elastic connector. Various structures are conceivable, such as those connected to external terminals provided on the outer member (control circuit board).
[0024]
According to the embodiment, the elastic connector 38 is configured to be in pressure contact with the input terminal 31d formed on the substrate of the liquid crystal panel via the anisotropic conductive film 36 and the double-sided flexible substrate 37. The contact resistance of the conductive connection portion between the elastic connector 38 and the liquid crystal panel can be reduced. That is, since the connection terminal portion 37b of the double-sided flexible board 37 has less restrictions on the material, unlike the input terminal 31d, the contact resistance with the terminal piece 38b of the elastic connector is small and the contact resistance is highly stable. For example, a contact surface made of gold or the like can be formed. Further, since it is possible to reduce the stress applied to the elastic connector 38 by reducing the contact resistance, the stress applied to the substrate 31 can be indirectly reduced, and an effect of avoiding a damage accident of the substrate 31 is also achieved. I can expect.
[0025]
Further, since the base body 37a of the flexible substrate 37 is flexible, the connection terminal portion 37b carried on the base body 37a is thicker with respect to the height variation of the input terminal 31d and the thickness variation of the anisotropic conductive film 36. Since it can respond flexibly to the vertical direction, the input terminal 31d and the connection terminal portion 37b can be reliably conductively connected. In addition, the flexibility of the anisotropic conductive film 36 and the base body 37a can ensure a compression margin of the conductive connection portion when the elastic connector 38 is pressed, so that the connection terminal portion 37b and the terminal piece 38b of the compression connector 38 Can be more reliably brought into contact with the entire surface, and the contact resistance can be further reduced by increasing the substantial contact area.
[0026]
Note that the electro-optical device of the present invention is not limited to the above-described illustrated examples, and various modifications can be made without departing from the scope of the present invention. In particular, the liquid crystal display device of the above embodiment includes a liquid crystal panel having a COG structure, but the present invention can be applied to various liquid crystal panels other than those described above. As for the driving method, the present invention can be applied to an active matrix driving type liquid crystal panel and a passive matrix driving type liquid crystal panel. Further, the present invention can be applied to any liquid crystal panel of transmissive type, reflective type, and transflective type. Furthermore, the present invention can be similarly applied to electroluminescence devices other than liquid crystal devices, plasma displays, and the like.
[0027]
FIG. 7 shows an invention related to an electronic apparatus of the present invention. FIG. 7 is a perspective view of a mobile phone provided with the embodiment of the electro-optical device. In addition to a plurality of operation buttons 1302, the cellular phone 1300 is provided with an earpiece 1304 and a mouthpiece 1306, and the liquid crystal display device 100 of the above embodiment is incorporated as a display unit. In this mobile phone 1300, since the liquid crystal display device 100 has the structure of the above embodiment, the reliability of the electrical contact portion between the liquid crystal display device 100 arranged in the mobile phone 1300 and the internal circuit is ensured. Can be improved.
[0028]
Note that the electro-optical device of the present invention is not limited to the above-described illustrated examples, and various modifications can be made without departing from the scope of the present invention.
[0029]
【The invention's effect】
As described above, according to the present invention, the flexible board is fixed on the input terminal, and the elastic connector is pressed against the flexible board. Since the connection terminal portion of the flexible substrate that can be selected and the terminal of the elastic connector are in contact with each other, the contact resistance can be reduced and the contact resistance can be stabilized. In addition, since the insulating support of the flexible substrate has flexibility, it is possible to increase the compression margin at the contact portion between the flexible substrate and the elastic connector, so that the contact area of the contact portion is increased. In addition, the contact state can be stabilized.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a liquid crystal panel and a conductive connection structure for its input terminal in an embodiment according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a conductive connection structure in the same embodiment.
FIG. 3 is a partial perspective view of a flexible substrate in the same embodiment.
FIG. 4 is a cross-sectional view showing another structural example of the flexible substrate in the same embodiment;
FIG. 5 is a schematic cross-sectional view showing a structural example of a conventional liquid crystal display device.
FIG. 6 is a schematic cross-sectional view showing another structural example of a conventional liquid crystal display device.
FIG. 7 is a perspective view showing an embodiment of a mobile phone as an example of an electronic apparatus according to the invention.
[Explanation of symbols]
30 Liquid crystal panel 31, 32 Substrate 31a Overhang portion 31d Input terminal 35 Semiconductor element 36 Anisotropic conductive film 37 Flexible substrate 37a Base 37b Connection terminal portion 37b-1, 37b-2 Conductor pattern portion 37b-3 Connection conductor (front and back) Connection part)
38 Elastic connector

Claims (7)

Electro-optic material is disposed on the substrate, an electro-optical device including a plurality of input terminals and a drive circuit for driving an electro-optical material on the base plate,
A plurality of connection terminal portions having a flexible substrate disposed on both surfaces of the insulating support, the connection terminal portion on one surface of the flexible substrate being fixed to the substrate in a conductive connection with the input terminal, and
An electro-optical device , wherein an elastic connector is connected to the connection terminal portion on the other surface of the flexible substrate, and the elastic connector is pressed against the input terminal via the flexible substrate . The substrate according to claim 1, further comprising a substrate facing the substrate.
  The substrate has a projecting portion that projects from the substrate facing the substrate,
  An electro-optical device, wherein the entire flexible substrate is disposed inside the overhanging portion.   3. The electro-optical device according to claim 1, wherein the flexible substrate is fixed to the substrate via an anisotropic conductive film.   4. The connection terminal portion according to claim 1, wherein the connection terminal portion includes a first conductor pattern portion formed on one surface of the insulating support of the flexible substrate and the other surface of the insulating support. An electro-optical device comprising: a second conductor pattern portion formed on the top surface; and a front and back connection portion that connects the first conductor pattern portion and the second conductor pattern portion.   5. The electro-optical device according to claim 1, wherein the electro-optical material is a liquid crystal.   6. The electro-optical device according to claim 5, wherein the input terminal is formed of a transparent conductor.   An electronic apparatus comprising the electro-optical device according to claim 1.

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