JP2004271819A - Electro-optical device, projection display device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light valve module which secures heat dissipation efficiency while minimizing structural restrictions. <P>SOLUTION: A light valve module 1 has an active matrix substrate 10 and a counter substrate 20 which hold a liquid crystal between them, a flexible substrate 30 connected to the active matrix substrate 10, and a liquid crystal driving element 35 mounted on the flexible substrate 30. A freely deformable heat sink 40 is connected to a surface opposite to the surface of the flexible substrate 30 on which the liquid crystal driving element 35 is mounted. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electro-optical device, a projection display device, and an electronic apparatus, and more particularly to a projection display device with small structural restrictions and a liquid crystal light valve module used for the same.
[0002]
[Prior art]
2. Description of the Related Art A projection display device (liquid crystal projector) that modulates light emitted from a lighting device with a light valve and then enlarges and projects the modulated light on a screen is known. The light valve used in the projection display device is configured such that an active matrix substrate and a counter substrate are bonded together with a sealant, and liquid crystal is sealed in a region defined by the sealant.
[0003]
One end of a flexible printed circuit (FPC) is connected to the active matrix substrate of the light valve. The other end of the FPC is connected to a circuit board on which a circuit for generating a control signal for a liquid crystal driving element is mounted.
[0004]
The liquid crystal sealed in the light valve is driven by a liquid crystal driving element such as an IC or LSI. As a method of mounting the driving element, there are COG (Chip On Glass) mounting and COF (Chip On Film) mounting. The COG mounting is to mount a driving element on an active matrix substrate made of a glass substrate or the like, and the COF mounting is to mount a driving element on an FPC. Among them, the COF mounting has an advantage that the driving elements can be mounted continuously on a TAB (Tape Automated Bonding) tape.
[0005]
By the way, driving elements such as ICs and LSIs generate heat when used. Since there are many other heating elements such as a light source inside the projection type liquid crystal display device, the driving element may be extremely heated by the heat generation and may be broken. Therefore, as disclosed in Patent Documents 1 and 2, a method has been proposed in which a heat radiating plate made of metal or the like is connected to the driving element to cool the driving element.
[0006]
[Patent Document 1]
JP-A-9-213852 [Patent Document 2]
JP-A-10-229255
[Problems to be solved by the invention]
Along with this, the projection type display device has a structural restriction of securing a space for disposing a heat sink. In particular, in order to improve the heat radiation efficiency of the driving element, it is necessary to increase the surface area of the heat radiating plate, but this causes a problem that the structural limitation in the projection display device becomes more remarkable.
[0008]
SUMMARY An advantage of some aspects of the invention is to provide an electro-optical device capable of improving heat radiation efficiency of an electronic component while minimizing a structural constraint of an electronic device. . Another object of the present invention is to provide an electronic device with small structural constraints.
[0009]
[Means for Solving the Problems]
In order to solve the above problem, an electro-optical device according to the present invention is an electro-optical device including a flexible substrate connected to a display device and an electronic component mounted on the flexible substrate, wherein the electronic component includes A heat sink that can be freely deformed is connected to the surface opposite to the mounting surface for the flexible substrate.
[0010]
According to the electro-optical device of the present invention, since the heat-dissipating plate that can be freely deformed is connected to the electronic component, it is possible to arrange the heat-dissipating plate in an arbitrary space inside an electronic device such as a projection display device. Become. Therefore, it is not necessary to secure a new space for arranging the heat radiating plate, and it is possible to minimize structural restrictions in the electronic device. Further, even when the surface area of the heat radiating plate is increased, the structural restriction of the electronic device can be minimized, and the heat radiation efficiency of the electronic component can be improved. Furthermore, according to the electro-optical device of the present invention, since the heat sink is connected to the surface of the electronic component opposite to the surface on which the flexible substrate is mounted, the heat sink functions as a light-shielding plate for the electronic component. Therefore, failure of the electronic component can be prevented.
[0011]
In addition, a separate heat sink may be connected to each of the plurality of electronic components mounted on the flexible substrate, but the same heat sink that can be freely deformed can be connected. As a result, the number of parts is reduced, and the cost can be reduced.
[0012]
The radiator plate can be formed of a metal having high thermal conductivity or the like, but the radiator plate may be freely plastically deformable. It is desirable to form an electric insulating film on at least one surface of the heat sink. According to these configurations, even when the heat sink has conductivity, it is possible to prevent an electrical short circuit via the discharge plate.
[0013]
On the other hand, an electronic component may generate heat by receiving light from a light source of a projection display device, for example, and may fail. Therefore, it is desirable that the heat radiating plate has a configuration having a light shielding property. By connecting a heat-radiating plate having a light-shielding property to the surface of the electronic component opposite to the surface on which the flexible board is mounted, the electronic component is shielded from light, and failure of the electronic component can be prevented.
[0014]
Further, a projection type display device according to the present invention includes the above-described electro-optical device. According to this configuration, it is possible to provide a projection display device with small structural constraints. In addition, by connecting a heat-radiating plate having a light-shielding property to the surface of the electronic component opposite to the surface on which the flexible board is mounted, the electronic component is shielded from light by the light source of the projection display device, and failure due to heat generation of the electronic component is caused. Can be prevented.
[0015]
On the other hand, an electronic apparatus of the present invention includes the above-described electro-optical device. According to this configuration, an electronic device with small structural restrictions can be provided.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing used in the following description, the scale of each member is appropriately changed in order to make each member a recognizable size.
[0017]
[Projection display device]
First, an embodiment of a projection display device according to the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram illustrating a main part of a projection display device according to the present embodiment. In this embodiment, a three-panel projection display device will be described as an example. The three-panel projection display device 100 mainly includes a light source 110, a light valve 120, a cross dichroic prism 130, a projection lens 140, and a circuit board 150.
[0018]
In FIG. 1, a light source 110 includes a lamp 111 such as a metal halide, and a reflector 112 that reflects light from the lamp 111. The light beam from the light source 110 enters the light valve 120 via an integrator optical system, a color light separation optical system, and a light guide optical system (not shown). Specifically, white light from the light source 110 is separated into three color lights of R (red), G (green), and B (blue) by a color light separation optical system, and each of them is incident on a separate light valve. FIG. 1 shows only one of them.
[0019]
For the light valve 120, a liquid crystal display device 1 according to the present embodiment described later is used. The light valve 120 has a function of modulating incident light in accordance with given image information to form an image. Light from each light valve 120 is synthesized by the cross dichroic prism 130 to generate light representing a color image. The combined light generated by the cross dichroic prism 130 is enlarged by the projection lens 140 and projected on a screen or the like, and an image is displayed.
[0020]
The light valve 120 is connected to a circuit board 150 via a flexible printed circuit (hereinafter, referred to as FPC) 30 described later. A circuit for generating image information to be given to the light valve 120 is mounted on the circuit board 150. The connection of the FPC 30 to the circuit board 150 is performed via a connector, solder, or the like. Also, since the light valve 120 and the circuit board 150 are connected by freely deforming the FPC 30, the projection display device 100 is formed compact.
[0021]
[Light valve module]
Next, a light valve module which is an embodiment of the electro-optical device according to the present invention will be described with reference to FIGS. FIG. 2 is a perspective view of the light valve module according to the present embodiment, and FIG. 3 is a cross-sectional view taken along line AA of FIG. FIG. 4 is an equivalent circuit diagram of a plurality of pixels. The light valve module 1 includes a light valve 120, an FPC 30, a liquid crystal driving element 35, and a heat sink 40. In this embodiment, an active matrix type light valve will be described as an example.
[0022]
As shown in FIG. 3, in a light valve 120 as a display device, an active matrix substrate 10 made of hard glass, quartz, or the like, and an opposing substrate 20 made of glass or the like are bonded together with a sealing material 24, and are surrounded by the sealing material 24. A liquid crystal 22, which is an electro-optical material, is sealed in the enclosed area. Note that, depending on the type of the liquid crystal 22 to be used, an operation mode such as a TN (Twisted Nematic) mode or an STN (Super Twisted Nematic) mode, and a normally white mode or a normally black mode, the outside of each of the substrates 10 and 20 is different. A phase difference plate, a polarizing plate, and the like (not shown) are arranged in a predetermined direction on the side surface.
[0023]
At the center of the active matrix substrate 10 surrounded by the sealing material 24, a plurality of dots (pixels) 11 are formed in a matrix as shown in FIG. Further, a thin film transistor (hereinafter, referred to as a TFT) 12 is formed in each dot 11 as a pixel switching element. The source of each TFT 12 is electrically connected to a data line 6a for supplying pixel signals S1, S2,..., Sn. The pixel signals S1, S2,..., Sn may be supplied line-sequentially to each data line 6a in this order, or may be supplied to a plurality of adjacent data lines 6a for each group. . The scanning line 3 a is electrically connected to the gate of each TFT 12. The scanning signals G1, G2,..., Gm are applied to the scanning line 3a in a pulsed manner at a predetermined timing in this order in a line-sequential manner. Further, a pixel electrode 14 is electrically connected to a drain of each TFT 12.
[0024]
Then, by turning on the TFT 12 as a switching element for a certain period, the pixel signals S1, S2,..., Sn supplied from the data line 6a are written into the liquid crystal of each pixel at a predetermined timing. The pixel signals S1, S2,..., Sn of a predetermined level written in the liquid crystal through the pixel electrodes 14 between the counter electrodes (not shown) formed inside the counter substrate 20 shown in FIG. It is kept for a certain period. Further, in order to prevent the held pixel signals S1, S2,..., And Sn from leaking, a storage capacitor 16 is added between the pixel electrode 14 and the capacitor line 3b. When a voltage signal is applied to the liquid crystal in this way, the orientation of the liquid crystal molecules changes according to the applied voltage level, so that the light incident on the light valve is modulated and gray scale display is possible.
[0025]
Note that a thin film diode (Thin Film Diode, hereinafter referred to as TFD) which is a two-terminal nonlinear element may be provided as a switching element instead of the TFT. In this case, a data line is connected to the TFD to supply a data signal. On the other hand, opposing electrodes are formed in a stripe shape inside the opposing substrate, and each opposing electrode functions as a scanning line to which a scanning signal is applied. The counter electrode side may be a data line to which a data signal is applied, and a wiring connected to the TFD may be a scanning line to which a scanning signal is applied.
[0026]
Each of the data lines 6a and each of the scanning lines 3a described above are routed to an end of the active matrix substrate 10, and a drive terminal is formed at the end.
[0027]
As shown in FIG. 2, one end of an FPC 30 which is a flexible substrate is connected to an end of the active matrix substrate 10. The FPC 30 is a flexible substrate made of a film such as polyimide. Note that a plurality of wirings are formed on the surface of the FPC 30 in correspondence with the drive terminals of the active matrix substrate 10. The FPC 30 is connected to the active matrix substrate 10 via an anisotropic conductive film (ACF: Anisotropic Conductive Film) not shown. The anisotropic conductive film is obtained by dispersing a large number of conductive particles in, for example, a thermoplastic or thermosetting adhesive resin.
[0028]
On the surface of the FPC 30, a liquid crystal driving element 35 such as an IC or an LSI, which is an electronic component, is mounted. Each terminal of the driving element 35 is connected to each wiring of the FPC 30 by FCB (Flip Chip Bonding) or the like.
[0029]
A heat sink 40 is connected to the surface of the driving element 35 opposite to the surface on which the FPC 30 is mounted via an adhesive or the like. The radiator plate 40 is formed in a foil shape from a metal having high thermal conductivity, such as Cu or Al. Generally, the heat sink 40 formed of metal foil can be freely plastically deformed. That is, the heat radiating plate 40 is deformed by a slight force, and maintains the deformed state even when the force is removed. In addition, plastic deformation may be performed as described above, but it may be deformed only when a force is applied, and may return to the original state when the force is removed. On the other hand, the heat radiating plate 40 is formed to have a light shielding property. Generally, the heat radiating plate 40 formed of a metal foil has a light shielding property. The light-shielding property may be provided by forming a light-shielding film on the surface of the heat sink.
[0030]
Since the freely deformable heat radiating plate 40 is connected to the driving element 35, the heat radiating plate 40 can be arranged in an arbitrary space inside the projection display device. Specifically, as shown in FIG. 1, if the heat radiating plate 40 is deformed along the FPC 30, the heat radiating plate 40 can be arranged in an arbitrary space inside the projection display device 100. Therefore, it is not necessary to secure a new space for disposing the heat radiating plate 40, and it is possible to minimize structural restrictions in the projection display device. Thus, it is possible to avoid an increase in the size of the projection display device.
[0031]
Further, in order to improve the heat radiation efficiency of the driving element 35, it is necessary to increase the surface area of the heat radiation plate 40. Even in such a case, the heat sink 40 can be freely plastically deformed and arranged in an arbitrary space inside the projection display device. The heat sink 40 may be plastically deformed, but may be deformed only when a force is applied, and may return to the original state when the force is removed. With such a configuration, the heat radiation efficiency of the driving element 35 can be improved while minimizing structural restrictions in the projection display device.
[0032]
In some cases, the driving element 35 may be damaged by receiving light and generating heat. In particular, in the projection type display device shown in FIG. 1, the light intensity of the light source 110 is high, and the driving element 35 may be heated to cause a failure. In this embodiment, since the heat-radiating plate having the light-shielding property is connected to the surface of the driving element 35 opposite to the surface on which the FPC 30 is mounted, the driving element 35 is shielded from the light source 110 of the projection display device 100. Thus, the failure of the driving element 35 can be prevented. In addition, if the heat radiating plate 40 is arranged so as to protrude greatly from the peripheral edge of the driving element 35, the light shielding of the driving element 35 can be performed more reliably.
[0033]
Further, since the heat radiating plate 40 is connected to the surface of the driving element 35 opposite to the surface on which the FPC 30 is mounted, the work of connecting the heat radiating plate 40 is simplified. In addition, the heat radiating plate 40 is arranged at a predetermined distance from the FPC 30, so that a short circuit between wirings formed on the surface of the FPC 30 can be avoided.
[0034]
Incidentally, since the heat radiating plate 40 is plastically deformed and maintained in a deformed state, the heat radiating plate 40 does not come into contact with the components of the projection display device. Therefore, even when the heat radiating plate 40 has conductivity, an electrical short circuit does not occur through the discharge plate 40 in principle. However, when a large external force acts on the projection display device and the heat dissipation plate 40 is bent, a short circuit may be exceptionally generated.
[0035]
Therefore, it is desirable to form the insulating layer 45 on the surface of the heat sink 40 as shown in FIG. The insulating layer 45 is made of an electrically insulating resin or the like, and is formed on both surfaces or one surface of the heat sink 40. Since the insulating layer 45 generally has a low thermal conductivity, if the insulating layer 45 is formed on both surfaces of the radiator plate 40, the heat radiation efficiency of the radiator plate 40 may be reduced. Therefore, it is desirable to form the insulating layer 45 only on one surface that requires electrical insulation. Further, the insulating layer may be formed only on a part that requires electrical insulation without forming the insulating layer on one entire surface of the heat sink.
[0036]
In FIG. 5A, an insulating layer 45 is formed on the surface of the heat sink 40 opposite to the surface connected to the liquid crystal driving element 35. Accordingly, even when the heat sink 40 has conductivity, it is possible to prevent a short circuit between the components of the projection display device and the driving element 35, and thus prevent the driving element 35 from malfunctioning.
[0037]
On the other hand, in FIG. 5B, the insulating layer 45 is formed on the surface of the heat sink 40 on the same side as the connection surface to the driving element 35. Thereby, short-circuiting of each wiring formed on the surface of the FPC 30 can be prevented via the heat dissipation plate 40 having conductivity. Note that an insulating layer 45 is formed on the surface of the heat radiating plate 40 at a portion other than a portion connected to the driving element 35. Thus, the heat radiating plate 40 is directly connected to the driving element 35 without passing through the insulating layer 45 having a low thermal conductivity, so that the heat radiating efficiency is not reduced.
[0038]
On the other hand, as shown in FIG. 6, a plurality of electronic components 36 and 37 such as driving elements may be mounted on the surface of the FPC 30. In this case, it is possible to connect a separate heat sink to each of the electronic components 36 and 37, but it is also possible to connect the same heat sink. In particular, even when the electronic components 36 and 37 have different heights, the same heat radiation plate 40 can be connected to each of the electronic components 36 and 37 by employing the freely deformable heat radiation plate 40. As a result, the number of parts is reduced, and the cost can be reduced. The heat radiating plate 40 may be plastically deformed, but may be deformed only when a force is applied, and may return to the original state when the force is removed.
[0039]
[Electronics]
With the same configuration as the light valve module according to the above-described embodiment, a liquid crystal panel module of a direct-view display device can be configured. Therefore, an example of an electronic device including the liquid crystal panel module will be described.
[0040]
FIG. 7 is a perspective view showing an example of a mobile phone. In FIG. 7, reference numeral 1000 denotes a mobile phone main body, and reference numeral 1001 denotes a liquid crystal display unit having a liquid crystal panel module. Since this mobile phone includes the liquid crystal panel module having the same configuration as the light valve module according to the above-described embodiment, it is possible to improve the heat radiation efficiency of the liquid crystal driving element while minimizing structural constraints. .
[0041]
Note that the technical scope of the present invention is not limited to the above-described embodiment, and includes various modifications of the above-described embodiment without departing from the spirit of the present invention. For example, in the embodiment, the light valve is taken as an example of the display device. However, the electro-optical device of the present invention can be configured using an organic EL display device, a DMD (Digital Mirror Device), or the like as a display device. In the embodiment, the three-panel projection display device is described as an example. However, the electro-optical device of the present invention can be used for a single-panel projection display device or a direct-view display device.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating a main part of a projection display device.
FIG. 2 is a perspective view of a light valve module.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is an equivalent circuit diagram of a plurality of pixels.
FIG. 5 is a sectional view of a light valve module in which an insulating layer is formed on a heat sink.
FIG. 6 is a sectional view of a light valve module in which the same heat sink is connected to a plurality of electronic components.
FIG. 7 is a perspective view of a mobile phone.
[Explanation of symbols]
1 light valve module 10 active matrix substrate 20 opposing substrate 30 flexible substrate 35 liquid crystal drive element 40 heat sink 100 projection display device 110 light source, 120 light valve 130 cross dichroic prism 140 projection lens 150 circuit board

Claims (7)

An electro-optical device having a flexible substrate connected to a display device and an electronic component mounted on the flexible substrate,
An electro-optical device, wherein a freely deformable heat radiating plate is connected to a surface of the electronic component opposite to a surface on which the flexible substrate is mounted. 2. The electro-optical device according to claim 1, wherein the same heat sink is connected to the plurality of electronic components mounted on the flexible substrate. The electro-optical device according to claim 1, wherein the heat sink is freely plastically deformable. 4. The electro-optical device according to claim 1, wherein an electric insulating layer is formed on at least one surface of the heat sink. The electro-optical device according to claim 1, wherein the heat radiating plate has a light shielding property. A projection display device comprising the electro-optical device according to claim 1. An electronic apparatus comprising the electro-optical device according to claim 1.

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