JP4479156B2 - Projection display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection display device.
[0002]
[Prior art]
In recent years, the demand for a high-resolution, low-power consumption and thin display device has increased, and research and development have been promoted. As one form of display device, there is known a projection display device (liquid crystal projector) that enlarges and projects an image emitted from an optical system using a light modulation device such as a liquid crystal light valve onto a screen through a projection lens. As the light modulation device, in addition to a liquid crystal light valve, a digital mirror device (hereinafter abbreviated as DMD) has been put into practical use.
By the way, in the liquid crystal light valve or the like used as the light modulation device of the projection display device as described above, there is a strong demand for cost reduction. In addition, a technique for realizing cost reduction of a liquid crystal device by mounting on a substrate holding a liquid crystal and simultaneously producing a switching element for a pixel and a semiconductor element for a driving circuit is disclosed.
[0003]
[Patent Document 1]
Japanese Patent No. 3133248 [0004]
[Problems to be solved by the invention]
According to the technique described in Patent Document 1, it is possible to realize a liquid crystal device that is superior in terms of reduction in the number of connection wirings, manufacturing efficiency of active elements, and the like, compared to a case where a drive circuit is provided outside. However, there is a strong demand for high definition and miniaturization in liquid crystal light valves and the like mounted on projection display devices. When a liquid crystal light valve having a drive circuit mounted on a substrate is used, (1) drive Miniaturization is hindered by occupying a certain substrate area in the circuit. (2) A liquid crystal light valve and a control circuit due to an increase in the number of connection wirings between the drive circuit and an external control circuit as the pixel becomes higher in definition. And (3) with the increase in the number of pixels, problems such as insufficient capability of the drive circuit mounted on the substrate have become apparent.
In addition, liquid crystal light valves and the like used in projection display devices are directly irradiated with light from a light source, so high light resistance is required. In a drive circuit mounted on the substrate of a liquid crystal light valve, high heat resistance is achieved. It is also required that no malfunction occurs due to intense light. However, in the above-mentioned Patent Document 1, the reliability of the drive circuit mounted on the substrate of the liquid crystal light valve is not studied.
[0005]
The present invention has been made to solve the above-described problems, and provides a projection display device that can realize downsizing and high performance of the device and has excellent reliability, preferably at low cost. The purpose is that.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a projection display device of the present invention includes a light source, a light modulation device that modulates light of the light source, and a projection device that projects light modulated by the light modulation device. In the projection display device, the light modulation device includes a main body that performs the light modulation and a COF substrate in which an integrated circuit chip is mounted on a flexible substrate, and an external device is provided via the COF substrate. It is connected to a control circuit, and the integrated circuit chip is arranged with its active surface facing away from the light source.
[0007]
The COF substrate is an integrated circuit chip mounted on a flexible substrate using COF (Chip on film / Chip on flexible print circuit) technology. Generally, wiring is formed between layers. One of the laminated substrates is provided with an opening region, and the integrated circuit chip is mounted on a wiring extending into the opening region.
In the liquid crystal display device described in Patent Document 1, the driving circuit is mounted on the panel to reduce the cost. However, a projection type display that requires a small and high-definition light modulation device. In device applications, it is difficult to reduce the size of a light modulation device body (for example, a liquid crystal device) mounted with a control circuit for controlling the drive. When trying to improve, it becomes difficult to mount the drive circuit on the main body. On the other hand, in the configuration of the present invention, the integrated circuit chip for driving and controlling the light modulation device is separated from the main body portion of the light modulation device, so that the main body portion of the light modulation device can be downsized. By using a COF substrate on which an integrated circuit chip that functions as a high-performance drive circuit is mounted, it becomes possible to easily configure a light modulation device that can display a high-resolution display image. As a result, a small and high-definition light modulation device can be easily manufactured, which can contribute to a reduction in manufacturing cost of the projection display device.
[0008]
In the present invention, since the integrated circuit chip is mounted on the COF substrate, the integrated circuit chip is compared with a case where the integrated circuit chip is mounted on a light modulation device that is directly irradiated with light from a light source. In addition, the integrated circuit chip is disposed with the active surface that is relatively susceptible to light facing away from the light source, so that it is less susceptible to light. ing. Therefore, according to the present invention, it is possible to provide a projection display device having excellent reliability.
[0009]
Next, in the projection display device of the invention, the integrated circuit chip mounted on the COF substrate constitutes at least a part of a drive circuit that outputs an image signal to the light modulation device. And
According to this configuration, among the circuits constituting the drive circuit, a circuit that requires a higher capability can be mounted on the COF substrate. Therefore, when the optical modulation device is made high-definition, Capability can be easily improved.
[0010]
Next, in the projection type display device of the present invention, a connection terminal for connecting the COF substrate and the light modulation device is formed at an edge of one surface side of the flexible substrate, and the connection terminal and the integrated The circuit chip is provided on the same surface of the flexible substrate.
According to this configuration, since a COF substrate having a terminal or a circuit mounted on one side can be used, there is no need to use a high-cost double-sided COF substrate, and a low-cost projection display device is provided. Can do.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing the projection type display device of the present embodiment, FIG. 2 is a side configuration diagram of the projection type display device, and FIG. 3 is a perspective configuration diagram of the liquid crystal light valve 22 shown in FIGS. is there. In all the drawings below, the film thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.
[0012]
As shown in FIG. 1, the projection display device of this embodiment is a three-plate type equipped with transmissive liquid crystal light valves 22-24 for different colors of R (red), G (green), and B (blue). Projection type color display device, illumination device 1 having light source 2, fly-eye lens 3, 4 and polarization conversion device 4d, dichroic mirrors 13, 14, reflection mirrors 15-17, lenses 18-20, liquid crystal light valve 22 ˜24, a color separation / synthesis system 30 having a cross dichroic prism 25 and a projection optical system 40 having a projection lens 26.
[0013]
The light source 2 includes a lamp 7 such as a high-pressure mercury lamp or a metal halide lamp, and a reflector 8 that reflects light from the lamp 7. Further, the first fly-eye lens 3 and the second fly-eye lens 4 from the light source 2 side are used as uniform illumination means for uniformizing the illuminance distribution of the light source light L in the liquid crystal light valves 22, 23, and 24 that are illuminated areas. Are installed sequentially. Each fly-eye lens 3, 4 is composed of a plurality of lenses 9, 10 (for example, 6 × 8 in this embodiment). The light L emitted from the light source 2 is made uniform in illuminance distribution by the fly-eye lenses 3 and 4 in the liquid crystal light valves 22 to 24 which are illuminated areas.
[0014]
The polarization conversion device 4d is composed of a polarization beam splitter array (PBS array) provided on the uniform illumination means side, and a half-wave plate array that converts the polarization direction of the polarized light reflected by the PBS array. The light polarization direction is aligned in one direction without impairing the light intensity.
[0015]
The dichroic mirrors 13 and 14 are formed by, for example, laminating a dielectric multilayer film on the glass surface, and selectively reflect light of a predetermined color and transmit light of other wavelengths. In other words, the blue / green light reflecting dichroic mirror 13 transmits the red light LR of the light flux from the light source 2 and reflects the blue light LB and the green light LG. The green light reflecting dichroic mirror 14 transmits the blue light LB and reflects the green light LG among the blue light LB and the green light LG reflected by the dichroic mirror 13.
[0016]
As a result, among the light L incident from the illumination device 1, the red light LR passes through the dichroic mirror 13, is reflected by the reflection mirror 17, and enters the red light light valve 22. The green light LG is reflected by the dichroic mirror 14 and enters the green light valve 23. The blue light LB passes through the dichroic mirror 14 and then enters the blue light valve 24 through the relay system 21 including the relay lens 18, the reflection mirror 15, the relay lens 19, the reflection mirror 16, and the relay lens 20. It has become.
[0017]
In the case of the present embodiment, the liquid crystal light valves 22 to 24 are configured as an active matrix type transmissive liquid crystal light valve, and are driven by a driving circuit described later based on the image signal subjected to signal processing. Yes. The color lights LR, LG, and LB modulated by the light valves 22 to 24 are incident on the cross dichroic prism 25.
The cross dichroic prism 25 has a structure in which right angle prisms are bonded to each other, and a mirror surface that reflects the red light LR and a mirror surface that reflects the blue light LB are formed in a cross shape on the inner surface. The three color lights LR, LG, and LB are combined by these mirror surfaces to form light representing a color image, and then enlarged and projected onto the screen 27 by the projection lens 26.
[0018]
Next, looking at the side configuration shown in FIG. 2, the color light LR color-separated from the light L emitted from the light source 2 enters the liquid crystal light valve 22 and is modulated, and the cross dichroic prism 25 and other color lights It is designed to be synthesized. In the present embodiment, as shown in FIG. 2, the liquid crystal light valve 22 includes a liquid crystal panel 35 and a COF substrate 32 connected to one substrate of the liquid crystal panel 35. Includes a film substrate (flexible substrate) 33 and a driver IC (integrated circuit chip) 34 mounted on one surface thereof.
[0019]
FIG. 3 is a perspective configuration diagram of the liquid crystal light valve 22 shown in FIG. In the liquid crystal panel 35 according to the present embodiment, a liquid crystal layer is sandwiched between an element substrate 35a and a counter substrate 35b arranged to face each other, and the two substrates 35a and 35b are displayed in a region where they are planarly overlapped. A pixel portion 39 as a region is formed. The pixel unit 39 has a plurality of pixels arranged in a matrix in plan view. Two drive circuits 37 and 38 are mounted on the peripheral portion of the element substrate 35a, and one drive circuit 37 is electrically connected to a plurality of connection portions 36 formed in the vicinity thereof. The COF substrate 32 includes a film substrate 33 and a driver IC 34 mounted on one surface side (the back surface side in the drawing). The driver IC 34 and the driver IC 34 are mounted on the edge of the substrate surface on the side where the driver IC 34 is mounted. A terminal for connecting to the drive circuit 37 is provided, and is connected to a terminal on the element substrate 35 a side to form a connection portion 36. That is, the driver IC 34 and the drive circuit 37 are electrically connected via the connection unit 36. In the case of the embodiment, the driver IC 34 and the terminal (connecting portion 36) of the COF substrate 33 are provided on the same surface side of the film substrate 33, so that a single-side mounting type COF substrate is used as the COF substrate 33. Can do. Therefore, the cost of the COF substrate 33 can be reduced, and as a result, the cost of the projection display device can be reduced.
[0020]
In the projection type display device of this embodiment, as shown in FIG. 2, the integrated circuit chip 34 mounted on the COF substrate 32 is arranged with its active surface 34 a facing away from the light source 2. With such a configuration, the active surface 34a is protected from the light of the light source 2 by the integrated circuit chip 34 itself, and the malfunction of the integrated circuit chip 34 due to the incidence of light on the active surface 34a can be effectively prevented. It has become.
The active surface 34a of the integrated circuit chip 34 refers to a surface on which elements are formed on a semiconductor substrate. In the form of a packaged chip, the active surface is usually formed on the mounting surface side of the package. When an integrated circuit chip is mounted on a printed circuit board, the printed circuit board functions as a light-shielding member, so that troubles due to light irradiation are less likely to occur. However, in the case of a COF board, it may be mounted on a translucent film substrate. Therefore, depending on the arrangement of the integrated circuit chip and the light source, an element malfunction of the integrated circuit chip may occur. In the present invention, since the arrangement of the active surface of the integrated circuit chip and the light source is defined as described above, even if the integrated circuit chip is mounted on a translucent flexible substrate, malfunction due to the light of the light source. This is a projection type display device that is excellent in reliability.
[0021]
In the projection type display device of the present embodiment, the liquid crystal light valve 22 that is a light modulation device has a configuration in which a driver IC 34 is mounted on a flexible film substrate 33, so that the element substrate 35 a of the liquid crystal panel 35. Compared with the case where all the drive circuits are mounted on the top, the area occupied by the circuit in the element substrate 35a can be reduced, and the liquid crystal panel 35 can be downsized. In addition, among the drive circuits that are required to improve performance with the high definition of the liquid crystal panel 35, the driver IC 34 may be configured mainly by a circuit that requires high capability, and the capability of the element may be relatively low. If the circuit is configured to be mounted on the element substrate 35a, the high-performance driver IC 34 can be easily applied, and the manufacturability of the liquid crystal panel 35 can be improved. The performance liquid crystal light valve 22 can be manufactured at low cost.
[0022]
Further, when the drive circuits 37 and 38 are external drive circuits, it is necessary to draw out an extremely large number of terminals to the element substrate 35a in order to connect the drive circuit and the signal wiring of the pixel portion. In the refined liquid crystal panel, the pitch of the connection terminals is particularly narrow, and it is difficult to form the connection wiring between the external drive circuit and the liquid crystal panel. On the other hand, like the liquid crystal light valve 22 of the present embodiment, the driver IC 34 and the built-in drive circuit 37 cooperate to drive the pixel unit 39, thereby reducing the number of connection units 36. Therefore, the liquid crystal panel 35 can be easily reduced in size and definition.
[0023]
As a specific configuration of the driver IC 34 and the drive circuits 37 and 38 provided in the liquid crystal light valve 22 shown in FIG. 3, for example, a configuration in which functions shown in FIG. . FIG. 4 is a block diagram illustrating a configuration example of the liquid crystal light valve according to the present embodiment. As illustrated in FIG. 4, the pixel unit 39 includes a plurality of pixels arranged in a matrix on the liquid crystal panel 35. In addition, a multiplexer (drive circuit) 37 and a Y driver (drive circuit) 38 are provided in the liquid crystal panel 35. The pixel unit 39 includes an active matrix type pixel having a TFT element as a switching element, specifically, a data line and a scanning line arranged in stripes in directions intersecting with each other, and the vicinity of the intersection. And a pixel electrode for driving the liquid crystal. The data lines are connected to the multiplexer 37, and the scanning lines are connected to the Y driver 38.
In addition, a driver IC 34 that is an external drive circuit is connected to the liquid crystal panel 35 through a signal line group 42, and a timing control circuit 41 that controls them is connected to the liquid crystal panel 35 and the driver IC 34. The pixel unit 39 is driven and controlled by a Y driver 38, a multiplexer 37, a driver IC 34, and a timing control circuit 41 which are driving circuits provided in the periphery thereof.
[0024]
Image data DATA, latch timing signal LP, shift register start signal ST, data clock signal CLX, and select signals S1, S2, and S3 shown in FIG. 4 are supplied from the timing control circuit 41 to the driver IC 34. . The timing control circuit 41 supplies a Y driver start signal DY and a line shift signal CLY to the liquid crystal panel 35. The driver IC 34 includes a selector that selects and outputs one image signal from the image data DATA input from the timing control circuit 41. The selector IC includes a shift register, a latch circuit, and a driver circuit. Are connected in a permutation.
The driver IC 34 inputs the image data DATA received from the timing control circuit 41 to the latch circuit, and from the plurality of image data DATA accumulated in the latch circuit based on the select signals S1, S2, S3 supplied simultaneously. One image data corresponding to the select signal is selected and output to the multiplexer 37 via the signal line group 42. On the other hand, the multiplexer 37 outputs the image data DATA received from the driver IC 34 to the data line of the pixel column corresponding to the select signals S1, S2, S3. The pixels in each row are switched by the gate signal output from the Y driver 38 to the scanning line in synchronization with the output to the data line, so that an image is displayed.
[0025]
According to the above configuration, a plurality of image data DATA input to the selector of the driver IC 34 is made to correspond to one of the three types of select signals, and only the image data DATA corresponding to the select signal is switched while switching these select signals. Since the signal is output to the multiplexer 37, the number of the signal line groups 42 connected to the liquid crystal panel and the drive circuit is reduced to 1/3 as compared with the case where the image data DATA is output to all the signal lines of the pixel column. Since the number of connection portions 36 shown in FIG. 3 can be reduced, the connection between the COF substrate 33 and the liquid crystal panel 35 can be facilitated. Since only the multiplexer 37 mainly composed of a switch circuit having a relatively simple structure is mounted on the liquid crystal panel 35, the area occupied by the drive circuit in the liquid crystal panel 35 can be reduced. This is extremely advantageous for downsizing. Furthermore, since the driver IC 34 is externally attached, a driver IC having higher capability can be easily applied, and high definition of the pixel portion 39 can be easily coped with.
[0026]
In the above embodiment, as shown in FIGS. 2 and 3, the terminal on the COF substrate 32 side constituting the terminal portion 36 is formed on the surface on which the driver IC 34 is mounted. Depending on the specifications of 22, it is necessary to arrange the counter substrate 35b on the light source 2 side as shown in FIG. In such a configuration, as shown in FIG. 4, the COF substrate 32 ′ in which the surface on which the integrated circuit chip 34 is mounted and the surface on which the terminals constituting the connection portion 36 are formed are opposite to each other. Should be used. With this configuration, even when the counter substrate 35b of the liquid crystal panel 35 is disposed on the light source 2 side, the active surface 34a of the integrated circuit chip 34 is disposed in the opposite direction to the light source 2 side, and the integrated circuit chip 34 It is effectively shielded by itself.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a projection display device according to an embodiment of the present invention.
FIG. 2 is a side configuration diagram of the same.
FIG. 3 is a perspective configuration diagram of the liquid crystal light valve shown in FIG. 2;
FIG. 4 is a block diagram illustrating a configuration example of a liquid crystal light valve.
FIG. 5 is a configuration diagram of another embodiment of the projection display device of the present invention.
[Explanation of symbols]
22-24 Liquid crystal light valve (light modulation device), 32 COF substrate, 33 film substrate, 34 driver IC (integrated circuit chip), 35 liquid crystal panel

Claims (2)

A projection display device comprising: a light source; a light modulation device that modulates light from the light source; and a projection device that projects light modulated by the light modulation device,
The light modulation device includes a main body that performs the light modulation and a COF substrate in which an integrated circuit chip is mounted on a light-transmitting flexible substrate, and is connected to an external control circuit via the COF substrate. Connected,
The active surface side of the integrated circuit chip is mounted on one surface side of the flexible substrate,
A connection terminal for connecting the COF substrate and the light modulation device is formed at an edge of one surface side of the flexible substrate on which the integrated circuit chip is mounted,
Provided on one of a pair of substrates constituting the light modulation device, the connection portion connected to the connection terminal is arranged to face the opposite side of the light source,
The projection display device , wherein the integrated circuit chip is arranged with an active surface thereof facing away from the light source . 2. The projection display device according to claim 1 , wherein the integrated circuit chip mounted on the COF substrate constitutes at least part of a drive circuit that outputs an image signal to the light modulation device. .

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