JP2004258221A - Optical component and liquid crystal projector using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide optical components having increased thermal conductivity and a larger area to be used for a projector apparatus. <P>SOLUTION: The optical components such as a heat radiation plate and a wave plate of a projector apparatus are made of quartz substrates, the angle θ(deg) between the principal surface of the quartz substrate and the XY-plane of the crystal is controlled to satisfy 0<θ<45. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
The present invention relates to an optical component used for a projector device.
[0002]
2. Description of the Related Art At present, color liquid crystal projector devices (hereinafter, referred to as projector devices) have been widely used in a wide range of applications from corporate use to general household use. Along with this, in the projector market, demands for higher luminance of images have been increasing. In recent years, optical components of projector devices have been using resin-based materials such as polarizing films in many cases to meet the demand for miniaturization and cost reduction. It is common to maintain the plane of the film by sticking the film. However, if the light amount of the light source is increased to meet the demand for higher brightness of the image, not only the light amount but also the heat amount increases, and deterioration such as deterioration of the resin material constituting the polarizing film occurs. I couldn't do that.
Therefore, Japanese Patent Application Laid-Open Nos. 2000-314809 and 2000-206507 propose a structure in which a polarizing film is attached to the surface of a sapphire substrate instead of a glass substrate. Sapphire has a significantly higher thermal conductivity at room temperature (25 ° C.) than 41 (W / m · K) of a glass substrate, which is 41 (W / m · K). Function as a heat sink, it is possible to suppress the deterioration of the polarizing film.
[0004] However, sapphire substrates are used in some high-end projector devices because their cost is about ten times as expensive as glass substrates, but inexpensive sapphire substrates are increasing in popularity in recent years. In a home projector device, an expensive sapphire substrate cannot be used, and thus an improvement in the amount of light has been a problem.
On the other hand, Japanese Patent Application Laid-Open No. 2002-014419 proposes a projector device using a quartz substrate as a heat radiating plate, which is not as good as a sapphire substrate but has a thermal conductivity which is more than ten times higher than a glass substrate. I have. When a quartz substrate is used, a heat sink can be realized at a price that is about 1/5 to 1/3 times that of a sapphire substrate.
[Problems to be solved by the invention]
Although the cost is lower than that of a sapphire substrate, the cost of a quartz substrate is two to three times that of a glass substrate. Therefore, a further cost reduction is required for use in a general household projector. . On the other hand, there is a problem that not only the brightness of the image projected on the screen is increased but also the definition thereof is high. As a technique for this, means for increasing the diameter of the optical system is used. In order to increase the diameter of the optical system, the area of the optical system components must be increased. Therefore, it is necessary to increase the area of the quartz substrate used for the heat sink.
However, it takes time to grow an artificial quartz crystal as a raw material for a quartz substrate, and the thickness of the artificial quartz crystal most used for industrial purposes in the crystal axis (Z-axis) direction is 20 to 25 mm. A growth period of about two months is required to obtain crystals of the order. In recent years, the size of a heat sink substrate required as an optical component for a projector is about 30 to 40 mm on a side, and it takes about 4 to 6 months to make a large artificial quartz crystal in order to respond to this. And the material cost jumps several times, which causes a problem that the merit in cost is reduced as compared with the sapphire substrate. The present invention solves the above-mentioned problems, and realizes a large-area heat sink plate corresponding to a projector device having a large diameter for high brightness and high definition at low cost by using quartz. The purpose of the present invention is to reduce the cost of the radiator plate for the above size.
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a surface acoustic wave filter according to the present invention, which is an optical component having a structure in which a resin optical film is attached to a main surface of a quartz substrate, An optical component, wherein an angle θ (deg) between the main surface of the quartz substrate and the XY plane of the crystal is 0 <θ <45. The invention according to claim 2 is the optical component according to claim 1, wherein the optical film is a polarizing film. The invention according to claim 3 is an optical component in which the wavelength plate is formed of a quartz substrate, wherein the angle θ (deg) between the main surface of the quartz substrate and the XY plane of the crystal is 0 <θ <45. An optical component characterized by the following. According to a fourth aspect of the present invention, there is provided a liquid crystal projector including the optical component according to the first aspect.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 shows a configuration of a projector device according to the present invention. The light emitted from the light source 1 passes through the polarization generating element 2 and the wavelength plate 12, and is uniformly collected and emitted by the condenser lens 3. Then, the light is decomposed by the beam splitter plate 4 (hereinafter, referred to as BMP). The BMP has a function of forming a multilayer film on an inclined surface of a plate and separating light into two lights, that is, transmitted light and reflected light. BMP4 transmits red light (R) and reflects blue light (B) and green light (G), while BMP5 transmits blue light (B) and reflects green light (G). . After the light separation, the red light (R) and the blue light (B) are reflected by the reflection mirror 6, pass through the incident side polarizing film 8, and enter the transmission type liquid crystal 9. Then, the red light (R) and the blue light (B) emitted from the transmission type liquid crystal 9 pass through the emission side polarizing film 10 and the wave plate 12, and then enter the combining prism 11. The green light (G) passes through the incident side polarizing film 8, the transmission type liquid crystal 9, and the outgoing side polarizing film 10, and then enters the combining prism 11. After each color enters the combining prism 11, the lights are combined and an image is projected on the screen 20.
In this embodiment, a quartz substrate is used as the heat radiating plate 7 for attaching the incident-side polarizing film 8 and the outgoing-side polarizing film 10. The quartz substrate is made of an artificial quartz crystal manufactured in a growing furnace called an autoclave. FIG. 2 shows the structure of the artificial quartz crystal. It is well known that quartz is a trigonal system made of a stable SiO2 single crystal, and a crystal is formed surrounded by crystal planes such as an R plane, an r plane, and an m plane. The crystal structure is represented by an X-axis, a Y-axis, and a Z-axis as shown, and the Z-axis is called a crystal axis. In order to use it as a quartz substrate, it is necessary to cut the artificial quartz crystal at a certain angle. Assuming that the angle between the main surface of the quartz substrate and the XY plane is θ, θ = 90 °, that is, in a quartz substrate having a main plane parallel to the crystal axis, the thermal conductivity becomes maximum, and θ = 0 °, ie, the XY plane. It is known that a quartz substrate having a main surface of has the lowest thermal conductivity. Therefore, when a quartz substrate is used as a heat sink for an optical component, it has been common sense to cut the quartz substrate in a direction parallel to the crystal axis to form the quartz substrate.
However, as shown in FIG. 3, a quartz substrate cut in a direction parallel to the crystal axis cannot have a large area and cannot be used for a large-diameter optical system component. In order to solve this problem, there is a method in which the growth period of the artificial quartz is lengthened to increase the thickness in the crystal axis direction to increase the area of the substrate. However, in the case of 20 to 25 mm, which is the size of the heatsink most used for industrial use, it grows in about two months. If this is attempted, it takes 4 to 6 months, and the production cost increases.
Therefore, when cutting the artificial quartz crystal, the present inventor can obtain a quartz substrate having a large area from the conventional quartz crystal size by making the cutting angle θ smaller than 90 ° as shown in FIG. I thought it might be.
Specifically, in a conventional crystal of artificial quartz having a thickness of 20 to 25 mm in the crystal axis direction, by setting the cutting angle θ (deg) in the range of 0 <θ <45, the cutting angle θ (deg) is set in the range of 0 <θ <45. Even with a crystal of artificial quartz having a thickness of about 20 mm, many large-sized quartz substrates of 30 to 40 mm can be obtained. Therefore, a large-area quartz substrate can be manufactured without increasing the growth period of the artificial quartz crystal, which greatly contributes to cost reduction.
Here, the relationship between the cutting angle of the artificial quartz crystal and the thermal conductivity of the quartz substrate was examined. FIG. 5 shows the relationship between the cutting angle of the artificial quartz crystal and the thermal conductivity of the quartz substrate at room temperature (25 ° C.). The horizontal axis represents the XY plane of the artificial quartz crystal and the main surface of the quartz substrate. And the vertical axis represents the thermal conductivity (W / m · K) of the quartz substrate when cut at that angle. According to the figure, the thermal conductivity of the quartz substrate when the cutting angle of the artificial quartz crystal is θ = 0 °, that is, when it is cut in a direction perpendicular to the crystal axis, is about 6.2 (W / m · K). The thermal conductivity of the quartz substrate when cut at a cutting angle θ = 90 °, ie, in a direction parallel to the crystal axis, is about 10.7 (W / m · K) as Take the maximum value. Since the thermal conductivity of the conventional glass substrate is 1 (W / m · K), it can be seen that the thermal conductivity of the quartz substrate is several times better at any cutting angle.
From the above, by setting the cutting angle θ (deg) of the artificial quartz crystal in the range of 0 <θ <45, a large-sized quartz substrate can be manufactured at low cost even in the conventional quartz crystal size. Although the thermal conductivity is somewhat inferior to that of cutting in the direction parallel to the crystal axis, the thermal conductivity is several times higher than that of the glass substrate. Can be released. In addition, after attaching an optical film to a large quartz substrate, it is possible to manufacture small-diameter optical components that have been conventionally used by so-called batch processing by dividing the optical film into small portions, so that the cost of small-sized optical components is reduced. Reduction can also be realized.
Although only the case where a quartz substrate having a cutting angle θ (deg) of 0 <θ <45 has been described as a heat radiating plate has been described above, this quartz substrate is applied to a wave plate as another embodiment. An example will be described. Wave plates that have the function of changing the polarization state of light by shifting the phase can cause variations in the amount of light at the center and end of the light if there is variation in the phase difference in the divergent or convergent light. There is a demand for a wave plate having a high incident angle dependence. Then, the incident angle dependence of a wavelength plate using a quartz substrate with a cutting angle θ (deg) of 0 <θ <45 was examined. The divergence direction of light in the 1 / 2λ wavelength plate 13 is represented by an angle as shown in FIG. 6A, and the incident angle dependence in each divergence direction is shown in FIG. 6B. In any of the diverging directions, the phase difference hardly changes from 180 ° even when the incident angle changes, indicating that the incident angle dependency is very excellent. Therefore, if a quartz substrate with a cutting angle θ (deg) of 0 <θ <45 is used as the wave plate, a wave plate having a large area and excellent incident angle dependency can be realized, and a high mass production effect can be obtained. Parts can be provided at low cost.
It is needless to say that the quartz substrate of the present invention can be applied to optical parts such as an optical lens, a beam splitter plate, and a transmission liquid crystal.
【The invention's effect】
As described above, according to the present invention, in the optical components of the projector device, the heat radiation effect is improved by using a quartz substrate, and the cutting angle of the artificial quartz crystal is increased so that a large substrate area can be obtained. Is adjusted, a large number of large-sized quartz substrates can be obtained even in a small-sized artificial quartz crystal, so that low-cost optical components can be provided, and a high-brightness and high-clarity projector device can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a structure of a projector device according to the present invention.
FIG. 2 is a perspective view of a crystal structure of an artificial quartz.
FIGS. 3A and 3B are views when the artificial quartz is cut at a cutting angle θ = 90 °, wherein FIG. 3A is a perspective view and FIG.
FIGS. 4A and 4B are views when the artificial quartz is cut at a cutting angle θ, and FIG. 4A is a perspective view and FIG.
FIG. 5 is a graph showing the relationship between the cutting angle of an artificial quartz crystal and the thermal conductivity of a quartz substrate.
FIGS. 6A and 6B are diagrams illustrating an angle of a divergence direction of light in a half-wave plate according to a second embodiment of the present invention, and FIG. It is a figure showing a relation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Polarization generation element 3 ... Condensing lens 4, 5 ... Beam splitter plate 6 ... Reflection mirror 7 ... Heat sink 8 ... Incident side polarizing film 9 ... Transmissive liquid crystal 10 ... Outgoing side polarizing film 11 ... Synthetic prism 12 ... Wave plate 13 1/2 wave plate 20 Screen

Claims (4)

An optical component having a structure in which a resin optical film is attached to a main surface of a quartz substrate, wherein an angle θ (deg) between the main surface of the quartz substrate and the XY plane of the crystal is 0 <θ <45. An optical component, characterized in that: The optical component according to claim 1, wherein the optical film is a polarizing film. An optical component having a wavelength plate formed of a quartz substrate, wherein an angle θ (deg) between a main surface of the quartz substrate and an XY plane of the crystal satisfies 0 <θ <45. A liquid crystal projector comprising the optical component according to claim 1.

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