JP4285030B2 - Projection display - Google Patents

Description

[0001]
BACKGROUND 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 a small structural restriction and a liquid crystal light valve module used therefor.
[0002]
[Prior art]
There is known a projection display device (liquid crystal projector) that modulates light emitted from an illuminating device with a light valve and then projects the enlarged light on a screen. The light valve used in this projection type display device is configured such that an active matrix substrate and a counter substrate are bonded together by a sealing material, and liquid crystal is sealed in a region partitioned by the sealing material.
[0003]
One end of a flexible printed circuit (hereinafter referred to as 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 control signal generation circuit 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 for mounting this driving element, there are COG (Chip On Glass) mounting and COF (Chip On Film) mounting. In the COG mounting, a driving element is mounted on an active matrix substrate made of a glass substrate or the like. In the COF mounting, a driving element is mounted on an FPC. Among them, COF mounting has an advantage that driving elements can be continuously mounted on a TAB (Tape Automated Bonding) tape.
[0005]
Incidentally, driving elements such as ICs and LSIs generate heat when used. Since there are many other heating elements such as a light source in the projection type liquid crystal display device, there is a risk that the driving element will be remarkably heated due to heat generation and may be damaged. Therefore, as shown in Patent Documents 1 and 2, a method has been proposed in which a heat sink made of metal or the like is connected to a drive element to cool the drive element.
[0006]
[Patent Document 1]
JP-A-9-213852 [Patent Document 2]
Japanese Patent Laid-Open No. 10-229255
[Problems to be solved by the invention]
As a result, the projection type display device has a structural restriction of securing a space for disposing the heat sink. In particular, in order to improve the heat dissipation efficiency of the driving element, it is necessary to increase the surface area of the heat dissipation plate, which causes a problem that structural restrictions in the projection display device become more conspicuous.
[0008]
SUMMARY An advantage of some aspects of the invention is that it provides an electro-optical device capable of improving the heat dissipation efficiency of an electronic component while minimizing the structural limitations of the electronic device. . It is another object of the present invention to provide an electronic device with small structural constraints.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, an electro-optical device of the present invention is an electro-optical device having a flexible substrate connected to a display device and an electronic component mounted on the flexible substrate, and the electronic component in the electronic component A heat-dissipating plate that can be freely deformed is connected to the surface opposite to the mounting surface with respect to the flexible substrate.
[0010]
According to the electro-optical device of the present invention, since the freely deformable heat sink is connected to the electronic component, for example, the heat sink can be arranged in an arbitrary space inside the electronic apparatus such as a projection display device. Become. Therefore, it is not necessary to secure a new space for disposing the heat sink, and structural restrictions in the electronic device can be minimized. Moreover, even when the surface area of the heat sink is increased, it is possible to minimize the structural constraints of the electronic device, and the heat dissipation efficiency of the electronic component can be improved. Furthermore, according to the electro-optical device of the present invention, the heat radiating plate is connected to the surface of the electronic component opposite to the mounting surface for the flexible substrate, so that the heat radiating plate functions as a light shielding plate for the electronic component. Therefore, failure of the electronic component can be prevented.
[0011]
In addition, separate heat sinks may be connected to the plurality of electronic components mounted on the flexible substrate, but the same heat sink that can be freely deformed can be connected. Thereby, the number of parts can be reduced and the cost can be reduced.
[0012]
In addition, although a heat sink can be formed with a metal etc. with high heat conductivity, the said heat sink may be freely plastically deformable. Moreover, it is desirable to form an electrical insulating film on at least one surface of the heat sink. According to these structures, even when a heat sink has electroconductivity, the electrical short circuit through a discharge plate can be prevented.
[0013]
On the other hand, for example, the electronic component may receive heat from the light source of the projection display device and generate heat, resulting in failure. Therefore, it is desirable that the heat radiating plate has a light shielding property. By connecting the heat radiating plate having a light shielding property to the surface of the electronic component opposite to the mounting surface with respect to the flexible substrate, the electronic component is shielded from light and failure of the electronic component can be prevented.
[0014]
A projection 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 sink with light shielding properties to the surface of the electronic component opposite to the mounting surface of the flexible substrate, the electronic component is shielded from the light source of the projection display device, and the electronic component is damaged due to heat generation. Can be prevented.
[0015]
On the other hand, an electronic apparatus according to the present invention includes the above-described electro-optical device. According to this configuration, it is possible to provide an electronic device with small structural constraints.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.
[0017]
[Projection type 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 showing a main part of a projection display device according to the present embodiment. In the present embodiment, a three-plate projection display device will be described as an example. The three-plate 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, the 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 through 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 the color light separation optical system, and each enters a separate light valve. FIG. 1 shows only one of them.
[0019]
The light valve 120 uses the liquid crystal display device 1 according to the present embodiment, which will be described later. The light valve 120 has a function of modulating an incident light according to given image information to form an image. Light from each light valve 120 is combined 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 onto a screen or the like, and an image is displayed.
[0020]
The light valve 120 is connected to the circuit board 150 via a flexible printed circuit (hereinafter referred to as FPC) 30 which will be described later. The circuit board 150 is mounted with a circuit for generating image information to be given to the light valve 120. The FPC 30 is connected to the circuit board 150 through a connector, solder, or the like. Further, 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 in a compact manner.
[0021]
[Light valve module]
Next, a light valve module which is an embodiment of the electro-optical device according to the 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 the 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 radiating plate 40. In the present embodiment, an active matrix type light valve will be described as an example.
[0022]
As shown in FIG. 3, in the light valve 120 as a display device, an active matrix substrate 10 made of hard glass or quartz and a counter substrate 20 made of glass or the like are bonded together by a sealing material 24 and surrounded by the sealing material 24. A liquid crystal 22 that is an electro-optic material is sealed in the region. Depending on the type of liquid crystal 22 to be used, the operation mode such as TN (Twisted Nematic) mode or STN (Super Twisted Nematic) mode, and the normally white mode or the normally black mode, the outside of each substrate 10, 20 A retardation plate, a polarizing plate, and the like (not shown) are arranged on the side surface in a predetermined direction.
[0023]
As shown in FIG. 4, a plurality of dots (pixels) 11 are formed in a matrix at the center of the active matrix substrate 10 surrounded by the sealing material 24. Each dot 11 is formed with a thin film transistor (hereinafter referred to as TFT) 12 as a pixel switching element. A data line 6a for supplying pixel signals S1, S2,..., Sn is electrically connected to the source of each TFT12. The pixel signals S1, S2,..., Sn may be supplied to each data line 6a in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. . Further, 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 line-sequential order in this order in a pulse manner at a predetermined timing. Further, a pixel electrode 14 is electrically connected to the 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 to the liquid crystal of each pixel at a predetermined timing. The pixel signals S 1, S 2,..., Sn written in the liquid crystal via the pixel electrode 14 in this way are transferred between the counter electrode (not shown) formed inside the counter substrate 20 shown in FIG. Hold for a certain period. In addition, a storage capacitor 16 is added between the pixel electrode 14 and the capacitor line 3b in order to prevent the held pixel signals S1, S2,... Sn from leaking. When the voltage signal is applied to the liquid crystal in this way, the orientation of the liquid crystal molecules changes depending on the applied voltage level, so that the light incident on the light valve is modulated to enable gradation display.
[0025]
Note that a thin film diode (hereinafter referred to as a TFD) that is a two-terminal nonlinear element may be provided as a switching element instead of a TFT. In this case, a data signal is supplied by connecting a data line to the TFD. On the other hand, counter electrodes are formed in stripes inside the counter substrate, and each counter electrode functions as a scanning line to which a scanning signal is applied. Note that the counter electrode side may be a data line to which a data signal is applied, and the wiring connected to the TFD may be a scanning line to which a scanning signal is applied.
[0026]
Each data line 6a and each scanning line 3a described above are routed to an end portion of the active matrix substrate 10, and a drive terminal is formed at the end portion.
[0027]
As shown in FIG. 2, one end of an FPC 30 that is a flexible substrate is connected to the end of the active matrix substrate 10. The FPC 30 is a flexible substrate made of a film such as polyimide. A plurality of wirings are formed on the surface of the FPC 30 corresponding to 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) (not shown). An anisotropic conductive film is obtained by, for example, dispersing a large number of conductive particles in a thermoplastic or thermosetting adhesive resin.
[0028]
A liquid crystal driving element 35 such as an IC or LSI, which is an electronic component, is mounted on the surface of the FPC 30. 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]
And the heat sink 40 is connected to the surface on the opposite side to the mounting surface in FPC30 in the element 35 for a drive through the adhesive agent etc. The heat sink 40 is formed in a foil shape with a metal such as Cu or Al having high thermal conductivity. Generally, the heat sink 40 formed of metal foil can be freely plastically deformed. That is, the heat radiating plate 40 is deformed with a slight force and maintains the deformed state even if the force is removed. Further, as described above, plastic deformation may be used, but deformation may be performed only when a force is applied, and the state may be restored when the force is removed. On the other hand, the heat sink 40 is formed to have a light shielding property. Generally, the heat sink 40 formed of metal foil has a light shielding property. In addition, you may provide light-shielding property by forming a light shielding film in the surface of a heat sink.
[0030]
Thus, since the heat sink 40 which can be freely deformed is connected to the driving element 35, the heat sink 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 disposed in an arbitrary space inside the projection display device 100. Therefore, it is not necessary to secure a new space for disposing the heat sink 40, and structural restrictions in the projection display device can be minimized. Thereby, the enlargement of a projection type display apparatus can be avoided.
[0031]
Further, in order to improve the heat dissipation efficiency of the driving element 35, it is necessary to increase the surface area of the heat sink 40. Even in that case, the heat radiating plate 40 can be freely plastically deformed and disposed in an arbitrary space inside the projection display device. 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. With such a configuration, it is possible to improve the heat dissipation efficiency of the driving element 35 while minimizing structural restrictions in the projection display device.
[0032]
Note that the driving element 35 may break down when it receives light and generates heat. In particular, in the projection type display device shown in FIG. 1, the light intensity of the light source 110 is strong, and there is a possibility that the driving element 35 may become hot and fail. In the present embodiment, since the heat radiating plate having a light shielding property is connected to the surface of the driving element 35 opposite to the mounting surface with respect to the FPC 30, the driving element 35 is shielded from the light source 110 of the projection display device 100. Thus, failure of the driving element 35 can be prevented. In addition, if the heat sink 40 is disposed so as to largely protrude from the peripheral portion of the driving element 35, the driving element 35 can be more reliably shielded from light.
[0033]
Moreover, since the heat sink 40 is connected to the surface of the drive element 35 opposite to the mounting surface for the FPC 30, the connection work of the heat sink 40 is simplified. In addition, the heat radiating plate 40 is arranged at a predetermined distance from the FPC 30, and a short circuit between wirings formed on the surface of the FPC 30 can be avoided.
[0034]
By the way, since the heat sink 40 is plastically deformed and maintains the deformed state, the heat sink 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 is applied to the projection display device and the heat sink 40 is bent, there is a possibility that a short circuit may occur exceptionally.
[0035]
Therefore, it is desirable to form an 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. In general, since the insulating layer 45 has low thermal conductivity, if the insulating layer 45 is formed on both surfaces of the heat sink 40, the heat dissipation efficiency of the heat sink 40 may be reduced. Therefore, it is desirable to form the insulating layer 45 only on one side that requires electrical insulation. Moreover, you may form an insulating layer only in the part which needs electrical insulation, without forming an insulating layer in the whole surface of a heat sink.
[0036]
In FIG. 5A, an insulating layer 45 is formed on the surface of the heat radiating plate 40 opposite to the connection surface to the liquid crystal driving element 35. Thereby, even when the heat sink 40 has conductivity, it is possible to prevent a short circuit between the component of the projection display device and the driving element 35, and it is possible to prevent a failure of the driving element 35.
[0037]
On the other hand, in FIG. 5B, the insulating layer 45 is formed on the surface of the heat radiating plate 40 on the same side as the connection surface to the driving element 35. Thereby, the short circuit of each wiring formed in the surface of FPC30 can be prevented via the heat sink 40 which has electroconductivity. Note that an insulating layer 45 is formed on the surface of the heat radiating plate 40 at a portion other than the portion connected to the driving element 35. Thereby, since the heat sink 40 is directly connected to the driving element 35 without the insulating layer 45 having a low thermal conductivity, the heat dissipation efficiency is not lowered.
[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 separate heat sinks to 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 radiating plate 40 can be connected to the electronic components 36 and 37 by adopting the heat radiating plate 40 that can be freely deformed. Thereby, the number of parts can be 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 its original state when the force is removed.
[0039]
[Electronics]
A liquid crystal panel module of a direct-view display device can also be configured with the same configuration as the light valve module according to the above-described embodiment. Therefore, an example of an electronic device provided with this 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 that of the light valve module according to the above-described embodiment, the heat dissipation efficiency of the liquid crystal driving element can be improved while minimizing structural constraints. .
[0041]
It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and includes those in which various modifications are made to the above-described embodiment without departing from the spirit of the present invention. For example, although the light valve is taken as an example of the display device in the embodiment, the electro-optical device of the present invention can be configured using an organic EL display device, DMD (Digital Mirror Device), or the like as the display device. In the embodiment, the description has been given by taking the three-plate projection display device as an example. However, the electro-optical device of the present invention can be used for a single-plate projection display device or a direct-view display device.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a main part of a projection display device.
FIG. 2 is a perspective view of a light valve module.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is an equivalent circuit diagram of a plurality of pixels.
FIG. 5 is a cross-sectional view of a light valve module in which an insulating layer is formed on a heat sink.
FIG. 6 is a cross-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 counter 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 substrate

Claims (4)

A projection type display device comprising: a flexible substrate connected to a display device; an electronic component mounted on the flexible substrate; and a light source that causes a light beam to enter the display device .
A heat sink that can be freely deformed is connected to the surface opposite to the mounting surface for the flexible substrate in the electronic component ,
The projection type display device , wherein the heat radiating plate having a light shielding property is disposed between the light source and the electronic component . The projection display device according to claim 1, wherein the same heat radiation plate is connected to the plurality of electronic components mounted on the flexible substrate. The projection display device according to claim 1, wherein the heat radiating plate is freely plastically deformable. The projection display device according to claim 1, wherein an electrically insulating layer is formed on at least one surface of the heat radiating plate.

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