JP2003195421A - Liquid crystal panel and transparent body for liquid crystal projector device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a liquid crystal projector device of attaining high luminance, high accuracy and miniaturization. <P>SOLUTION: A liquid crystal panel is constituted of holding liquid crystal in a gap between a transparent substrate located on the light incident side an a transparent substrate located on the light exit side and arranging a sapphire substrate on the incident or exit side transparent substrate. Consequently a heat radiation characteristic is improved, the display of surface dust is reduced and a polarization characteristic is maintained. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel and a transparent body used in a liquid crystal projector device.

[0002]

2. Description of the Related Art A liquid crystal projector device that has been used mainly for home theater applications has been used to project a personal computer image as it is by improving the projected image by improving the definition of a liquid crystal panel and the brightness of a lamp. It has evolved into a tool.

This liquid crystal projector device is shown, for example, in FIG.
It is configured as shown in. The light source 1 is a high-intensity lamp light source such as a metal halide lamp, a xenon lamp, and a UHP, and the light projected from the light source 1 is reflected by the spherical reflecting mirror 2 to cut infrared rays, ultraviolet rays, and the like.
To remove unnecessary infrared rays and ultraviolet rays. Then, after passing through the integrator lens 4 and the condenser lens 5 to collect the light, the light is passed through the incident side polarization plate 6 and the liquid crystal panel 8
Incident on. The light emitted from the liquid crystal panel 8 passes through the emission side polarization plate 7 and is enlarged and projected by the projection lens 9.
An image is displayed on the screen in the front.

This structure is of a single plate type using one liquid crystal panel equipped with a color filter. In addition to this single plate type, three liquid crystal panels are provided corresponding to the decomposed light of the light sources of RGB three primary colors. A built-in three-plate type is also generally known.

In this case, as shown in FIG. 2, a dichroic mirror 10 that transmits / reflects light according to the wavelength of light, a synthetic prism 11 that synthesizes light, and a total reflection mirror 12 are used. And the dichroic mirror 10
The light from the light source is decomposed into red (R), green (G), and blue (B), transmitted to each individual liquid crystal panel 8, combined by the combining prism 11, and projected.

In the case of these liquid crystal projector devices, since the polarizing plates 6 and 7 are used in the liquid crystal image forming section, light is largely absorbed, and in order to reduce the size of the device, it is close to 1 inch. It is unavoidable to reduce the brightness of the projected image by, for example, enlarging and projecting an image of the liquid crystal panel 8 whose area is downsized to tens of inches to hundreds of inches.

Therefore, as the light source 2, a high-intensity lamp such as a high-luminance metal halide lamp, UHP lamp, or xenon lamp is used. Moreover, the intended use is
As it expands to a presentation tool that projects and uses PC images as it is, the demand for smaller size, higher definition, and higher brightness is increasing, and lamps with higher output are being selected. .

Therefore, in the liquid crystal projector device, inconvenience due to heat has become an important issue.

For example, an iodine-based polarizing plate is generally used as a polarizing plate constituting a liquid crystal display section.
Since the heat resistance / moisture heat resistance is not sufficient, a dye-based polarizing plate excellent in light resistance / heat resistance / humidity heat resistance is used especially in a liquid crystal projector (Japanese Patent Laid-Open No. 9-22008).
And Japanese Patent Laid-Open No. 9-22009).

However, in particular, in the case of the polarizing plate 6 on the incident side, since the light transmittance is only about 40%, most of the light is absorbed and heat is generated, and there is a problem that the characteristics cannot be maintained at 70 ° C. or higher. . Further, the liquid crystal panel 8 itself is also weak against heat, and there is a problem that the characteristics are impaired when the temperature exceeds 60 ° C. Therefore, in the liquid crystal projector device, various cooling methods have been devised as described below.

(1) An air-cooling system in which a cooling fan is attached to the heat-generating part The incident-side polarizing plate 6, the liquid crystal panel 8, the heat-generating part such as the outgoing-side polarizing plate 7, the light source 1, and the power supply part are cooled by a cooling fan. Exhaust hot air.

(2) As shown in FIG. 1, the incident side polarizing plate 6 is installed at a distance of about 1 to 5 mm from the liquid crystal panel 8 to prevent the heat of the polarizing plate 6 from being directly transmitted to the liquid crystal panel 8. Cooling efficiency is increased by flowing cooling air in the meantime.

(3) A heat-dissipating glass plate having a thermal conductivity of 1 W / m · K or more is provided on the outer surface of the liquid crystal panel 8 through a hermetically sealed space to enhance the heat dissipating effect against the heat generated by the liquid crystal panel 8 and to cool the air. This prevents dust from adhering to the liquid crystal panel 8.

(4) A liquid cooling type heat exchange medium is filled with a liquid to enhance cooling efficiency (see Japanese Patent Publication No. 6-58474).

(5) Electronic cooling system such as a Peltier device An electronic cooling device using a Peltier device or the like is attached for forced cooling.

(6) A polarization converter is installed immediately after the light source Before the light from the light source 1 is incident on the polarizing plate 6, the polarization direction is aligned by the converter to reduce the amount of light absorbed by the polarizing plate 6. .

[0017]

However, the above-mentioned cooling methods also have the following problems.

(1) In the case of an air cooling system using a cooling fan,
There is a problem of noise and dust adhesion. Increasing the amount of air blow to obtain sufficient cooling effect causes high-speed fan rotation and large size, which causes noise problems, making it unsuitable for giving presentations in a quiet room or for use as a home theater. .

By separating the incident side polarizing plate 6 which is a heating element as shown in (2), the influence on the liquid crystal panel 8 can be reduced and the heat radiation effect can be enhanced, but the effect is still limited. There is. Further, the blue plate glass or the white plate glass used as a plate for holding the polarizer in the polarizing plate 6 also has poor thermal conductivity and the heat dissipation effect becomes insufficient, and as in the case of (1), the output of the cooling fan is eventually increased. I could not help solving the problems of noise and dust adhesion as described above.

(3) When a heat-dissipating glass plate is installed on the outer surface of the liquid crystal panel 8, the effect of removing the focus when dust adheres and not affecting the projection surface can be obtained, but the glass plate does not conduct heat. Even if the rate was good, there were only 2 W / mK or less, and a sufficient heat dissipation effect was not obtained.

(4) With respect to the liquid cooling type, there is a problem in terms of reliability because pressure release, bubble generation, foreign matters mixed in, leakage of cooling medium, etc. occur as the temperature rises. Further, there is also a problem that a large-scale liquid cooling mechanism is required and the entire apparatus becomes large.

(5) In the case of the solid-state cooling system in which an electronic cooling device such as a Peltier element is added, not only the cost of the entire liquid crystal projector device is significantly increased, but also a sufficient cooling effect is not obtained.

(6) It is intended to reduce the amount of heat generated by passing through the polarization converter and converting in advance the polarization components that were all absorbed by the polarizing plate 6 into the transmission polarization axis of the polarizing plate 6. However, since about 20% of the light is absorbed and heat is generated, if the liquid crystal panel 8 is downsized and the strength of the lamp per unit area is increased, the cooling effect is insufficient.

As described above, it was not possible to obtain a sufficient cooling effect with a simple structure by any of the cooling methods.
In addition to the above-mentioned polarizing plate 6, the problem of heat generation occurs in various parts.

For example, the transparent substrate forming the pixel electrode and the switching element located on the incident side, which constitutes the liquid crystal panel 8, is currently made of quartz glass having a low thermal conductivity of about 1.2 W / m · K. Since it is configured, there is a problem that heat accumulated in the liquid crystal panel 8 cannot be efficiently released.

Further, as shown in FIG. 2, the liquid crystal projector of a system in which the light from the light source 1 is separated into three color lights of RGB, an image corresponding to each color is displayed, and combined by using the combining prism 11 or the like. In the device, the dichroic mirror 10
Is used to separate the light from the light source 1. The dichroic mirror 10 is currently manufactured by applying a film on the surface of blue plate glass or white plate glass that selects and transmits and reflects the wavelength of the light source. However, this part also causes heat generation due to light absorption. However, this causes a problem of raising the temperature of the entire device.

Further, when light is incident on the optical system from the light source 1, it has been performed in advance to cut off infrared rays which are unnecessary heat sources. Normally, the IR cut filter 3 is also made of soda lime glass or glass. Since white plate glass is used and its thermal conductivity is low, it accumulates heat, causing a rise in the temperature of the entire device.

On the other hand, since the light source 1 is single and the illuminance on the irradiation surface cannot be made uniform, the integrator lens 4 is generally used to diffuse the light source intensity. As the integrator lens 4, usually, a large number of lenses manufactured by die-pressing optical glass such as Pyrex (R) glass are built in one plate. As a material having improved characteristics, a material such as quartz glass that utilizes the total reflection on the side surface of a prism is used. In this case, the refractive index is 1.
Since it is as small as about 46, the total reflection angle becomes large, it is necessary to set the length of the prismatic rod to be long, and the number of pseudo light sources is small.

[0029]

SUMMARY OF THE INVENTION In view of the above, the present invention holds a liquid crystal in a gap between a transparent substrate located on the incident side of light and a transparent substrate located on the outgoing side, and the transparent substrate on the incident side or the outgoing side is The liquid crystal panel is characterized by comprising a sapphire substrate.

In the sapphire substrate, the angle between the C-axis direction or the C-axis projection line direction and the polarization transmission axis to be transmitted is within ± 2 °, or the axis orthogonal to the C-axis should be transmitted. It is characterized in that the angle formed by the polarized light transmission axis is within ± 2 °, or the angle formed by the C plane and the plane perpendicular to the transmission direction of the polarized light to be transmitted is within ± 2 °.

Furthermore, the surface of the sapphire substrate is coated with an antireflection coating.

A transparent adhesive material having a Shore hardness of 30 or less is 10 to 70 μm between the sapphire substrate and the transparent substrate.
It is characterized in that it is adhered by interposing with a thickness of.

Further, according to the present invention, the above-mentioned lens in the liquid crystal projector device is adapted to project the light from the light source through the lens and the polarizing plate through the liquid crystal panel.
At least one kind of transparent material for a polarizer holding plate in a polarizing plate and a liquid crystal panel, which is formed of a sapphire substrate, and the sapphire substrate transmits in the C-axis direction or the C-axis projection line direction. The angle with the polarized light transmission axis to be transmitted is within ± 2 °, or the angle formed by the axis orthogonal to the C axis and the polarized light transmission axis to be transmitted is within ± 2 °, or transmitted with the C plane. It is characterized in that it is installed so that the angle formed with the plane perpendicular to the transmission direction of the desired polarized light is within ± 2 °.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the light source 1 is a high-intensity lamp light source such as a metal halide lamp, a xenon lamp, and a UHP, and the light projected from the light source is reflected by the spherical reflecting mirror 2 to emit infrared rays or ultraviolet rays. The unnecessary infrared rays and ultraviolet rays are removed by passing through the filter 3 to be cut. Then, after passing through the integrator lens 4 and the condenser lens 5 to collect the light, the light is passed through the incident side polarization plate 6 and the liquid crystal panel 8
Incident on. The light emitted from the liquid crystal panel 8 passes through the emission side polarization plate 7 and is enlarged and projected by the projection lens 9.
An image is displayed on the screen in the front.

Further, although this structure is of a single plate type using one liquid crystal panel 8, as another embodiment, RG is used.
Corresponding to the light source separation light of B3 primary color, 3 liquid crystal panels 8
There is also a three-sheet type that incorporates.

As shown in FIG. 2, this is a dichroic mirror 10 that transmits and reflects light according to the wavelength of light, a synthetic prism 11 that synthesizes light, and a total reflection mirror 1.
2 is used. Then, the dichroic mirror 10 allows the light from the light source to be red (R), green (G), and blue (B).
And is transmitted to the individual liquid crystal panels 8 respectively, combined by the combining prism 11 and projected.

In the present invention, in the liquid crystal projector device shown in FIGS. 1 and 2, the dichroic mirror 10, the filter 3, the lens 4, the polarizing plate holding plate in the polarizing plates 6 and 7, and the liquid crystal panel 8 are constituted. At least one of transparent bodies such as a transparent substrate is formed of a sapphire substrate. Therefore, since the sapphire substrate has high thermal conductivity, it is possible to efficiently dissipate the heat generated by the above-mentioned components.

First, an embodiment in which a sapphire substrate is applied to the holding plates of the polarizing plates 6 and 7 will be described.

As shown in FIG. 3, the polarizer 13 is bonded to the surface of the holding plate 15 made of a sapphire substrate with a transparent adhesive to form the polarizing plates 6 and 7. At this time, the polarizer 1
The angle formed by the transmission polarization axis 14 of No. 3 and the axis of the sapphire substrate constituting the holding plate 15 indicating the C-axis or the C-axis projection line direction or the axis orthogonal to the C-axis (for example, the M-axis) 16 is preferably ± 2 °. Are joined to each other within ± 0.5 °.

FIG. 5 shows a state in which the polarizing plates 6 and 7 bonded as shown in FIG. 3 are set in front of and behind the liquid crystal panel 8 and irradiated with light. In this case, the entrance side is installed with a space of 1 to 5 mm from the liquid crystal panel 8, and the exit side is directly attached to the surface of the liquid crystal panel 8 by using a transparent adhesive to form the polarizer 13.
The sides were stuck together.

In this way, the thermal conductivity is 42 W / m.
・ K and sapphire substrate with a high holding plate 15 and polarizer 1
By bonding with 3, the heat storage due to absorption of light that could not be transmitted through the polarizer 13 is conducted to the sapphire substrate,
It can dissipate heat efficiently. Furthermore, by using a cooling fan in combination, the heat accumulated in the polarizing plate 6 can be dissipated very efficiently.

In this embodiment, the polarizer 13
The reason why the angle between the transmission polarization axis 14 and the C axis of the sapphire substrate forming the holding plate 15 or the projection line of the C axis or the axis 16 orthogonal to the C axis is controlled within ± 2 °, preferably within ± 0.5 ° The reason is that the polarized light arranged by the polarizer 13 does not generate optical rotation due to birefringence in the sapphire crystal. For example, when the angle exceeds the above range, the image projected from the liquid crystal projector device is affected by disturbance or the like.

Further, as shown in FIG. 4, the influence of the birefringence can also be obtained by setting the plane orientation of the main surface 15a of the holding plate 15 made of a sapphire substrate within the C plane ± 2 °, preferably ± 0.5 °. It was possible to eliminate it and make a stable image.

Regarding the positional relationship between the polarizer 13 and the holding plate 15 in the polarizing plate 6, for the polarizing plate 6 on the incident side of the liquid crystal panel 8, the polarizing body 13 is installed closer to the liquid crystal panel 8 than the holding plate 15. Then, regarding the polarizing plate 7 on the output side,
The display contrast of the liquid crystal panel 8 is further improved when the polarizer 13 is installed closer to the liquid crystal panel 8 than the holding plate 15.

The reason for this is that it is important that the polarization characteristics before and after the liquid crystal panel 8 are not changed as much as possible, and even if the axial direction and the plane direction of the sapphire holding plate 15 are set with high accuracy, they are transmitted. This is because it is difficult to set the change in polarization characteristics to zero. With such an arrangement, the contrast characteristics could be realized at almost the same level as in the case where sapphire was not used.

In the embodiment of FIG. 5, the polarizing plate 6 on the incident side is separated from the liquid crystal panel 8, but as shown in FIG. 6, the polarizing plate 6 is directly bonded to the liquid crystal panel 8. Even if it is taken, if sapphire having good thermal conductivity is used as the holding plate 15, a sufficient heat dissipation effect can be obtained and the cooling state can be maintained. With this structure, the holding plate 1 made of sapphire exposed to cooling air from the liquid crystal display surface.
5. Since the distance from the outer surface side can be increased, even if dust adheres to the surface of the holding plate 15, it is difficult to focus and it is possible to prevent the quality of the projected image from deteriorating.

The sapphire substrate used as the holding plate 15 can be further improved in transparency by applying an antireflection coating on one side or both sides. In addition, the anti-reflection coating is also designed to match its refractive index with its adhesive surface and surface that comes into contact with air.
It was possible to further improve the transmittance.

For example, the surface of the sapphire substrate in contact with air is coated with an antireflection coating having a refractive index of about 1.0. In this case, the antireflection coating has a refractive index of 1.33 ±.
Any material within the range of 0.15 may be used, and for example, MgF2 having a refractive index of 1.38 is used. In addition, it is preferable to apply an antireflection coating on the bonding surface with other members to a refractive index of 1.38 to 1.55 according to the refractive index of the transparent adhesive material described later.

On the sapphire substrate attached to the outer surface of the liquid crystal panel 8 on the emission side, at least one surface is coated with a light-shielding frame having a transmittance of less than 1%, which is larger than the effective pixel area of the liquid crystal panel 8 by 0.1 mm or more. By doing so, it was possible to prevent the problem that the projected image is deteriorated in contrast due to scattered light from the surroundings. The light-shielding film may be a silk-screen printing film or a chromium-based vapor deposition film.

When the polarizing plates 6 and 7 are actually constructed by using the sapphire substrate as the holding plate 15, compared with the case of using the conventional blue plate glass or white plate glass as the holding plate 15,
An improvement in the cooling effect of 10 to 15 ° C. or more was observed.

Next, an embodiment in which a sapphire substrate is used as the transparent substrate forming the liquid crystal panel 8 will be described.

The liquid crystal panel 8 has a structure in which liquid crystal is held in a gap between a transparent substrate which forms a pixel electrode and a switching element located on the incident side and a transparent substrate which forms a counter electrode located on the emitting side. These transparent substrates are made of a sapphire substrate, or separately from these, a transparent substrate made of a sapphire substrate is provided on the incident side or the emission side of the liquid crystal panel 8.

In the embodiment shown in FIG. 7, a transparent substrate 18 made of a sapphire substrate is bonded to the entrance side and the exit side of the liquid crystal panel 8 so that a space of at least 0.1 mm or less is opened and sealed. .

Here, the reason why a gap is formed between the liquid crystal panel 8 and the transparent substrate 18 will be described. Since the liquid crystal panel 8 used in the liquid crystal projector device is used by enlarging and projecting, it is not possible to enclose beads for maintaining a constant interval together with the liquid crystal, and a structure in which a constant interval is maintained only by the outer peripheral sealing tank. Has become. Therefore, when the transparent substrate 18 of sapphire is directly contacted and set, the surface of the liquid crystal panel 8 is deformed due to thermal expansion due to temperature change and the quality of the projected image is degraded.

Therefore, by providing the transparent substrate 18 with a space, it is possible to prevent these deformations. Further, in order to efficiently transfer the heat stored in the liquid crystal panel 8 to the transparent substrate 18 in the outer peripheral portion, it is better to make the gap as narrow as possible. Therefore, by keeping the gap at least 0.1 mm or less, both It was confirmed that the characteristics were satisfied.

In this embodiment, an example in which the transparent substrate 18 is joined in a closed space structure is shown, but the transparent substrate 18 may be attached so as to come into contact with it through a flexible transparent adhesive material instead of the space. In this case, the transparent adhesive material may have a Shore hardness of 30 or less as shown in Table 1. Also, considering the influence on the image quality, if the thickness is 10 μm or more, there is no problem, and as a result of conducting an experiment confirming the cooling property by heat conduction, as shown in Table 2, the thickness is 70 μm or less. I found that

[0058]

[Table 1]

[0059]

[Table 2]

Further, the liquid crystal panel 8 is provided with the transparent substrate 18 on both the light incident side and the light emitting side to show higher heat dissipation, but it is possible to obtain a high heat dissipation effect on either one of the sides. is there. Furthermore, by providing an antireflection coating on one side or both sides of the sapphire substrate forming the transparent substrate 18, it is possible to further improve the transmission characteristics.

The sapphire substrate used as the transparent substrate 18 has a C axis of the sapphire substrate, a C-axis projection line, or an axis orthogonal to the C-axis within ± 2 ° with respect to the polarization axis of the polarized light to be transmitted, preferably. Is set within 0.5 °, it is possible to avoid the problem of degrading the quality of the projected image due to optical rotation. Also, by setting the plane orientation of the sapphire substrate to be the C plane ± 2 °, preferably ± 0.5 °, it is possible to prevent the quality of the projected image from being affected.

Also, by covering the liquid crystal panel 8 with the heat radiating plate of the transparent substrate 18 made of sapphire, even if dust adheres to the transparent substrate 8, the distance from the liquid crystal panel 8 can be increased, so that the image is out of focus. The quality will not be hindered. still,
It was confirmed by experiments that this thickness is required to be 1 mm or more.

In addition, the holding plate 15 constituting the polarizing plates 6 and 7 is made of a sapphire substrate, so that about 5
The effect of lowering the temperature of the liquid crystal panel surface above ℃ was obtained.

Next, in the embodiment shown in FIG. 8, a transparent substrate 19 for forming a pixel electrode and a switching element on the incident side and a transparent substrate 20 for forming a counter electrode on the outgoing side which constitute the transmissive liquid crystal panel 8. Is formed of a sapphire substrate to form the liquid crystal panel 8.

In each of the sapphire substrates forming the transparent substrates 19 and 20, the angle formed by the polarization axis of polarized light to be transmitted and the C-axis or C-axis projection line direction of the crystal axis of sapphire or the axis orthogonal to the C-axis is , ± 2 °, preferably ± 0.
It is necessary to configure the angle to be within 5 ° or to set the plane orientation of the sapphire substrate within the C plane ± 2 °, preferably within ± 0.5 °.

In this case, since the transparent substrates 19 and 20 constituting the liquid crystal panel 8 themselves are made of sapphire having sufficient heat dissipation characteristics, it is not necessary to separately provide a polarizing plate, and the transparent substrates 19 and 20 can be directly attached to the outer surface side. The polarizer 13 may be joined. In this way, the transparent substrates 19 and 20 can also serve as a holding plate for the polarizer 13, and a compact and low-cost structure can be obtained.

In this case, it is possible to further improve the transmission characteristics by applying an antireflection coating to one or both surfaces of the sapphire substrate. However, the transparent adhesive material for adhering the polarizer 13 is generally 1. Since it has a refractive index of 4 to 1.5 and also partially plays a role of antireflection, good transmission characteristics can be realized without applying an antireflection coating. Further, the transmission characteristics are improved by applying an antireflection coating designed according to the refractive index.

In the structure shown in FIG. 8, when a cooling structure combined with a cooling fan is adopted, a temperature reduction effect of about 15 to 20 ° C. can be realized as compared with the case where the same structure is formed by a quartz substrate, and The optical path of the system can be shortened by about 5%.

Next, the embodiment shown in FIG. 9 is used as a transparent substrate 21 for forming the reflection electrodes and switching elements of the reflection type liquid crystal panel 8 and a transparent substrate 22 for forming the counter electrodes on the input / output sides. Therefore, also in this case, the heat dissipation effect can be improved.

In this embodiment, since the sapphire substrate used as the transparent substrate 21 for forming the reflective electrode and the switching element does not affect the characteristics of polarized light, its axis or plane orientation may be arbitrary and the surface may be finished. Only the reflective surface side needs to be mirror-finished. Then, the heat sink 23 for heat dissipation can be directly attached to the back side of the transparent substrate 21. In addition, the transparent substrate 22 forming the counter electrode on the input / output side
As for the transparent sapphire substrate used as, since the incident light and the reflected emitted light have different polarization directions, the principal surface thereof is within ± 2 ° of the C plane, preferably ± 0. It is good to set it within 5 °.

Further, another embodiment of the present invention will be described.

A projector device for enlarging and projecting an image is
Generally, when displaying a high-definition image, the light source is divided into RGB three-color light as shown in FIG. 2 and an image corresponding to each color is displayed regardless of the transmissive liquid crystal system, the reflective liquid crystal system, or the DLP system. It is displayed and combined using a prism or the like.

Among these, the dichroic mirror 10 which plays a role of separating the colors of the light source 1 is formed of a sapphire substrate, and a film for transmitting / reflecting by selecting the wavelength of the light source 1 is formed on the surface thereof. .

As a result, the dichroic mirror 1
It has become possible to efficiently dissipate the accumulated heat of 0 and reduce the temperature of the entire device. Also for the sapphire substrate used for these, the C axis, the C axis projection line direction, or the axis orthogonal to the C axis is within ± 2 °, preferably within ± 0.5 ° with respect to the polarization transmission axis adjusted after or before transmission. Or the main surface of the sapphire substrate is within ± 2 ° of the C plane, preferably within ± 0.5 °.

As another embodiment, a sapphire substrate is used as an infrared cut filter 3 for preventing infrared rays from the light source 1 which cause unnecessary heat generation to enter the optical system, and an infrared cut film is formed on the surface thereof. Can also be generated. In this case, since the filter 3 is arranged immediately after the light source 1 and generates a large amount of heat, it is possible to efficiently dissipate the heat by cooling it with the cooling fan for the light source 1 and reduce the temperature of the entire device. Greater effect.

Also for the sapphire substrate used for these, with respect to the polarization transmission axis adjusted after or before transmission,
The C-axis or the C-axis projection line direction or the direction orthogonal to the C-axis is configured to be within ± 2 °, preferably ± 0.5 °, or the main surface of the sapphire substrate is within ± 2 ° of the C-plane. It is preferably within ± 0.5 °.

Further, it is also possible to join a metal radiation fin to the above-mentioned sapphire substrate. For example, in FIG. 10, a metallized layer 24 of Mo—Mn or the like is formed on the outer circumference of a sapphire substrate used as the holding plate 15 of the polarizing plate 6, and metal heat radiation fins 25 are brazed and joined.

In this case, the heat accumulated in the polarizer 13 is conducted to the holding plate 15 made of sapphire, and further conducted to the metal radiating fins 25 having good thermal conductivity. And
Metal radiating fins 2 with a large surface area to improve heat dissipation
By cooling 5 with a cooling fan, the cooling effect can be further enhanced.

According to the experiment, as compared with the case of using sapphire alone, the effect of reducing the temperature by 5 to 10 ° C. was further improved. This makes it possible to satisfy a much lower and stable operating condition with respect to the characteristic guarantee temperature of 70 ° C. of the polarizer 13.

Although the Mo—Mn metallization method is used in this embodiment, the same effect can be obtained by using the active metal method or the like.

Further, by constructing a general resin frame (mold) used for positioning the set of the optical system with a high heat conductive material such as aluminum, it becomes possible to transfer heat more efficiently, and the device The entire structure can be used as a heat dissipation structure.

Further, another embodiment of the present invention will be described.

In a liquid crystal projector device for enlarging and projecting an image, as shown in FIG.
The rod-type integrator lens 26 for diffusing is made of sapphire.

Since sapphire is a transparent material having a high refractive index of No. 1.768, when the quadrangular prism integrator lens 26 is manufactured, the total reflection angle can be set small, and optical glass such as quartz can be used. Compared with the integrator lens created in 1., the diffusivity can be greatly improved, and the overall size can be designed compact.

As a result, it is possible to improve the uniformity of the image brightness by the liquid crystal projector device, and it is also possible to improve the heat dissipation. It is possible to further improve the transmission efficiency by applying a non-reflection coating to the end surface portions of the prisms, which are the entrance surface and the exit surface of the integrator lens 26 to be created.

Next, the manufacturing process of the sapphire of the present invention will be described.

Single crystal sapphire is made of alumina (Al2O
It is a single crystal body of 3), and Al atoms and O atoms are arranged to form crystals. As shown in FIG. 12, sapphire is a hexagonal system, the central axis of which is the C axis, and the plane perpendicular to this is the C plane (0001). The A-axis (a1, a2, a3) extending radially from the C-axis and the plane perpendicular to the A-axis are the A-plane (11-20). As shown in the figure, the R plane exists at a constant angle (about 32.383 °) with the C axis.
Note that these axes and planes can be analyzed by X-ray diffraction.

The single crystal sapphire of the present invention is manufactured by the EFG method (Edge-defined Film-fed Gro).
wth method). That is, high-purity alumina is melted in an inert atmosphere, a ribbon-shaped sapphire single-crystal growing molybdenum die having slits inside is positioned so as to come into contact with the alumina melt, and the alumina melt is subjected to capillary action. Alumina melt was guided to the upper end of the molybdenum die by using, and brought into contact with a seed crystal (seed) there, and then the seed was pulled up to grow sapphire which is single crystal alumina. In pulling up and growing this substrate material, the main surface of the seed is set to the plane orientation in which the seed is desired to grow, and its growth axis is set as a pulling axis and pulled up. By pulling up in this way, it is possible to accurately grow the plane orientation of the main surface as a plane orientation and an axial orientation. The method for growing single crystal sapphire is EFG.
Not only the method but also other methods such as Czochralski method, but if you want to obtain a square crystal like this time,
Since the columnar crystal shape is inefficient, the EFG method that can accurately obtain a plate crystal is suitable.

The single crystal sapphire thus obtained is ground into a predetermined shape with a diamond wheel or the like, and then lapping is carried out using diamond abrasive grains.

Next, while supplying a liquid in which spherical colloidal particles of SiO ₂ (colloidal silica) having a particle diameter of 50 nm or less are dispersed as a polishing liquid, the single crystal sapphire and the polishing cloth are slid relative to each other for precision polishing. (CMP) is performed. By carrying out polishing in this manner, it is possible to remove the destructive layer generated by the above grinding and lapping without newly generating strain, and it is excellent in transparency and has a good smooth surface even when used as a substrate. Is completed.

Next, Table 3 shows a comparison of the characteristic values of sapphire and quartz glass / BK-7 / float glass (blue plate glass) which are currently used transparent materials.

As is clear from Table 3, sapphire is overwhelmingly excellent in thermal conductivity and heat dissipation. Further, since the refractive index is also relatively high, it can be seen that it also has high characteristics when used as an integrator lens.

Further, because of its high strength, it is possible to design thinner than other materials, and it is possible to design a compact optical system as a whole. Furthermore, it has excellent heat resistance and is made of polycrystalline silicon (p-s
i) It can be used without any problem even in a high temperature process of the TFT manufacturing process.

[0094]

[Table 3]

[0095]

As described above, according to the present invention, the liquid crystal is held in the gap between the transparent substrate located on the light incident side and the transparent substrate located on the outgoing side, and the transparent substrate on the incident side or the outgoing side. By configuring the liquid crystal panel with the sapphire substrate, the heat dissipation effect is improved, and it is possible to realize a high-luminance and miniaturized liquid crystal projector device without the problem of characteristic deterioration due to heat generation, and dust is attached. However, it is difficult to focus, and it is possible to prevent the quality of the projected image from deteriorating.

Further, by accurately controlling the axial and plane orientations of the crystal of the sapphire substrate, it is possible to realize a projector device which faithfully transmits the polarization characteristics and can project.

According to the present invention, it is possible to significantly increase the brightness and definition of the projected image by the liquid crystal projector device.
Further, it can contribute to downsizing of the device.

[Brief description of drawings]

FIG. 1 is a schematic view of a general transmissive liquid crystal single plate type projector device.

FIG. 2 is a schematic view of a general transmissive liquid crystal three-panel projector device.

FIG. 3 is a diagram showing a polarizing plate in the liquid crystal projector device of the present invention.

FIG. 4 is a diagram showing a polarizing plate in the liquid crystal projector device of the present invention.

FIG. 5 is a diagram showing a liquid crystal panel including the polarizing plates of FIGS.

FIG. 6 is a diagram showing a liquid crystal panel including the polarizing plates of FIGS.

FIG. 7 is a diagram showing another embodiment of the present invention.

FIG. 8 is a diagram showing another embodiment of the present invention.

FIG. 9 is a diagram showing another embodiment of the present invention.

FIG. 10 is a diagram showing another embodiment of the present invention.

FIG. 11 is a diagram showing another embodiment of the present invention.

FIG. 12 is a diagram showing a crystal structure of sapphire.

[Explanation of symbols]

1 ... Light source 2 ... Reflector 3 ... Filter 4 ... Integrator lens 5 ... Lens 6 ... Polarizing plate 7 ... Polarizing plate 8 ... Liquid crystal panel 9 ... Projection lens 10 ... Dichroic mirror 11: Synthetic prism 12 ... total reflection mirror 13 ... Polarizer 14 ... Polarization axis 15 ... Holding plate 16 ... C-axis or C-axis projection line direction 18: Transparent substrate 19: Transparent substrate 20 ... Transparent substrate 21: Transparent substrate 22 ... Transparent substrate 23 ... Heat sink material 24 ... Metallized layer 25 ... Metal radiation fin 26 ... Integrator lens

Continued front page    F term (reference) 2H088 EA13 EA14 EA15 HA01 HA08                       HA12 HA13 HA18 HA21 HA28                       MA03 MA06                 2H090 JB04 JD05 JD06 JD19 LA04                       LA11 LA12 LA15 LA16 LA20                 2H091 FA05X FA08X FA08Z FA14Z                       FA26X FA37X FA41Z FB06                       FD15 GA01 GA13 GA17 LA04                       LA11                 2K103 AA02 AA05 AA11 AB07 BB02                       BC16 CA06 CA67 CA75 CA76                       DA03 DA11

Claims (5)

[Claims] 1. A liquid crystal panel in which a liquid crystal is held in a gap between a transparent substrate located on the light incident side and a transparent substrate located on the outgoing side, and a sapphire substrate is provided on the incident side or outgoing side transparent substrate. 2. The sapphire substrate has an angle of ± 2 between a C-axis direction or a C-axis projection line direction and a polarization transmission axis to be transmitted.
Is less than or equal to ± 2 ° between the axis orthogonal to the C axis and the polarization transmission axis to be transmitted, or between the C plane and the plane perpendicular to the transmission direction of the polarization to be transmitted. The liquid crystal panel according to claim 1, wherein the angle formed is within ± 2 °. 3. The liquid crystal panel according to claim 1, wherein the surface of the sapphire substrate is provided with an antireflection coating. 4. A transparent adhesive material having a Shore hardness of 30 or less with a thickness of 10 to 70 μm interposed and bonded between the sapphire substrate and the transparent substrate.
The liquid crystal panel according to any one of 3 above. 5. A lens holding plate for a polarizer in a polarizing plate, and a liquid crystal panel in a liquid crystal projector device, wherein light from a light source is passed through a liquid crystal panel through a lens and a polarizing plate to project the light. At least one transparent body of a transparent substrate, which is formed of a sapphire substrate, wherein the sapphire substrate has an angle between a C axis direction or a C axis projection line direction and a polarization transmission axis to be transmitted within ± 2 °. Or the angle between the axis orthogonal to the C axis and the polarization transmission axis to be transmitted is within ± 2 °, or the angle between the C plane and the plane perpendicular to the transmission direction of the polarization to be transmitted is A transparent body for a liquid crystal projector device, which is installed so as to be within ± 2 °.