JP2000352615A - Polarizing plate with glass and liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of phase difference in glass of a polarizing plate with glass even when the plate is irradiated with intense light and to obtain a polarizing plate having excellent light resistance by adhering a polarizing plate to glass having a specified absolute value of the average coefficient of linear expansion or smaller. SOLUTION: A polarizing plate is adhered to glass having an absolute value of <=10×10-7/ deg.C of the average coefft. of linear expansion. For example, a polarizing plate 101 is adhered with an adhesive to the whole or most of the region on one surface of a glass sheet 102. Or, polarizing plates 103, 104 are adhered with an adhesive to 1 to 3 faces of a prism 105. Or, a polarizing plate 106 is adhered with an adhesive to the flat face of a planoconvex lens 107. As for the polarizing plate to be used, a laminated body prepared by adsorbing and dispersing a polarizing element such as boron and dichronic dye in a stretched film such as PVA as the base body and laminating transparent supporting films such as TAC on the both surfaces of the film can be easily used. From the viewpoint of the light resistance, a film using a dichroic dye as the polarizing element is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a polarizing plate with glass having excellent light resistance. In addition, the present invention relates to a liquid crystal device using the polarizing plate with glass, particularly to a liquid crystal projector.

[0002]

2. Description of the Related Art A liquid crystal device using a polarizing plate is sometimes used in a liquid crystal projector or an outdoor display device under extremely strong light. In a liquid crystal device used in such an environment, color unevenness and contrast unevenness generated at a peripheral portion of a screen often pose a problem.

[0003] Such a phenomenon is mainly caused by the fact that the polarizing plate absorbs strong light and generates heat. Therefore, in a conventional liquid crystal projector, as disclosed in Japanese Patent Application Laid-Open No. 62-109024, the temperature of the liquid crystal cell is prevented from rising by disposing the polarizing plate away from the liquid crystal cell (liquid crystal light valve). It was devised. In that case,
JP-A-10-39138, JP-A-10-39139, and JP-A-10-48590, as disclosed in JP-A-10-48590, a polarizing plate is attached to a support such as glass, or JP-A-63-39138. No. 4217, as disclosed in JP-A-63-74024,
The plane was maintained by sandwiching the polarizing plate between two glass plates. Otherwise, the polarizing plate may be deformed by the heat generated by the polarizing plate, partially losing the polarizing ability or causing a phase difference, thereby possibly damaging the display.

FIG. 11 is the same drawing as FIG. 1 of JP-A-10-48590, and the structure of a conventional liquid crystal projector will be described with reference to FIG. In FIG. 11, a light beam emitted from a light source 1 passes through a condenser lens 2 and an ultraviolet / infrared cut filter 3, and blue (B) is separated by a first dichroic mirror 4 for decomposition, and a second decomposition dichroic mirror 4 is used. The light is separated into green (G) and red (R) by the dichroic mirror 4 'to obtain three primary colors. The R, G, and B light rays are transmitted through a polarizing plate 5 with glass.
f, only the light of the polarized light of a certain direction passes through the liquid crystal cell 6.
R, 6G, and 6B. The polarizing plate with glass 5f is disposed apart from the liquid crystal cell. Also, a polarizing plate 5r is attached to the emission side of the liquid crystal cell. The R, G, and B light beams that have passed through the exit-side polarizing plate 5r are sequentially combined by the first combining dichroic mirror 7 and the second combining dichroic mirror 7 ', and are then projected onto the screen 10 via the projection lens 9. Projected. 8 is a reflection mirror.

It should be noted that JP-A-10-39138 and JP-A-10-39138
In JP-48590, glass recommended for a polarizing plate with glass is soda glass (average coefficient of linear expansion = 8).
1 to 92 × 10 ⁻⁷ / ° C.), borosilicate glass (average coefficient of linear expansion = 32 to 65 × 10 ⁻⁷ / ° C.), crown glass (average coefficient of linear expansion ≒ 90 × 10 ⁻⁷ / ° C.), and the like. Was.

[0006]

However, even if the temperature rise of the liquid crystal cell is suppressed by the above-described configuration, the liquid crystal device using the conventional polarizing plate with glass eliminates the unevenness of the polarizing plate. Could not be done.

[0007] When the cause was analyzed, surprisingly, there was no change in the polarizing plate itself due to heat, and a small phase difference was generated around the glass plate. It turned out to be the cause of unevenness. The reason why a phase difference occurs in glass is as follows. That is, there is a distribution in the intensity of light applied to the polarizing plate with glass. Usually, the light applied to the central part is strong, and the light applied to the peripheral part is weak. In addition, there are areas where light does not shine and areas where no polarizing plate is attached on the periphery of the glass. Then, distortion occurs because the temperature of the glass varies depending on the location and the degree of thermal expansion varies. This distortion causes a phase difference due to the photoelastic effect.

In view of the above, an object of the present invention is to provide a polarizing plate with excellent light resistance by devising such that a phase difference does not occur in the glass even when the polarizing plate with glass is irradiated with strong light. And It is another object of the present invention to provide a bright liquid crystal projector using the polarizing plate with glass.

[0009]

Means taken by the present invention to solve the above problems are as follows.

[0010] The polarizing plate with glass according to the first aspect is characterized in that the polarizing plate is attached to glass having an absolute value of an average linear expansion coefficient of 10 × 10 ⁻⁷ / ° C. or less. The average linear expansion coefficient is 1 ° C from 0 ° C to 300 ° C specified in JIS R 3102-1978 “Test method for average linear expansion coefficient of glass”.
Means the average linear expansion coefficient per unit. Generally, it is known that glass or crystallized glass having a high SiO ₂ content has a low average linear expansion coefficient. Examples of the glass having an average linear expansion coefficient in the above range include quartz glass, 7913 95% silicate glass manufactured by Corning, and Neoceram N-0 manufactured by Nippon Electric Glass. According to the above configuration, even if the glass has some temperature unevenness, a large distortion and a large phase difference do not occur, so that a polarizing plate with glass excellent in light resistance can be obtained. More preferably, it is desirable to use glass whose absolute value of the average linear expansion coefficient is 3 × 10 ⁻⁷ / ° C. or less. As such a glass, there is, for example, 7971 titanium silicate glass manufactured by Corning. With such a configuration, even if the glass has large temperature unevenness, almost no distortion occurs, and an effect is obtained that a polarizing plate with glass having excellent light resistance can be obtained.

The polarizing plate with glass according to claim 2 is characterized in that the glass is any one of a glass plate, a prism and a lens. This glass plate may be a glass plate dedicated to supporting a polarizing plate, but may be a color filter or a Japanese Patent Laid-Open Publication No.
The glass plate constituting the liquid prism as disclosed in Japanese Patent Application Laid-Open No. 5-61130 may also be used. Further, the prism and lens are often formed of optical glass represented by BK7 of Schott, but may be formed of glass having an average linear expansion coefficient according to claim 1. According to the above configuration, there is an effect that a polarizing plate with glass excellent in light resistance can be efficiently contained in a liquid crystal projector.

[0012] The polarizing plate with glass according to claim 3 is characterized in that the polarizing plate is attached to a glass plate having a thickness of 0.1 mm or more and 0.5 mm or less. Depending on the glass maker, the lineup of normal sheet glass thickness is
0.03mm, 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.3mm, 0.4m
m, 0.5mm, 0.55mm, 0.7mm, 1.1mm, 1.3mm, 1.5mm, 2.1m
m, 2.4mm, 2.7mm, 3.2mm, 5.6mm, 9.5mm ... Of these, the glass thickness often used as an optical component is
It is between 0.7 mm and 2.7 mm. The smaller the glass thickness, the smaller the phase difference that occurs, but the thickness with which the unevenness improving effect is clearly visible is 0.5 mm or less. The glass as the support needs to have a thickness of at least 0.2 mm in consideration of its flexibility, but can be used up to a thickness of 0.1 mm by bonding to a prism or the like as described later. According to the above configuration, the phase difference caused by the distortion of the glass is suppressed, so that there is an effect that a polarizing plate with glass excellent in light resistance can be obtained. Further, by combining the above-described configuration with the configuration of the first aspect, it is possible to obtain a greater effect. More preferably, it is desirable to use glass having a glass thickness of 0.2 mm or more and 0.4 mm or less. With such a configuration, there is an effect that a polarizing plate with glass having more excellent light resistance can be obtained.

The polarizing plate with glass according to claim 4, wherein the axis of the glass plate is opposite to the surface to which the polarizing plate is attached so that most of the light transmitted through the polarizing plate is transmitted. And another polarizing plate is attached.
The axial arrangement of the polarizing plates on both sides is usually parallel to each other, but they can be attached at any angle by combining a half-wave plate or the like. According to the above configuration, the polarization disorder caused by the distortion of the glass is corrected while the second polarizing plate is accompanied by a small amount of light absorption, so that an effect of obtaining a polarizing plate with glass excellent in light resistance can be obtained. is there. In addition, since two polarizing plates are used, a secondary effect can be expected in that even if one polarizing plate exposed to strong light deteriorates, it can be compensated for by the second polarizing plate.

A liquid crystal projector according to claim 5, wherein the light source, a first polarizing plate for absorbing a specific polarized component of light emitted from the light source, and a liquid crystal light for modulating light transmitted through the first polarizing plate. A liquid crystal projector comprising: a bulb; a second polarizing plate that absorbs a specific polarization component of light transmitted through the liquid crystal light valve; and a projection unit configured to project light transmitted through the second polarizing plate. The glass-equipped polarizing plate is used as at least the second polarizing plate of the two polarizing plates. Of course, it is most preferable to use the glass-equipped polarizing plate of the present invention for both the first polarizing plate and the second polarizing plate.However, when it is necessary to use only one of them for various reasons, the second polarizing plate side It is desirable to use the polarizing plate with glass of the present invention. Because, in the case of a normal liquid crystal projector, a device that converts light into linearly polarized light with a certain degree of uniformity is inserted between the light source and the first polarizing plate, so that relatively little light is absorbed by the first polarizing plate. Because.
According to the above configuration, there is an effect that color unevenness and contrast unevenness hardly occur around the projection screen of the liquid crystal projector.

According to a sixth aspect of the present invention, in the liquid crystal projector, the polarizing plate with glass is disposed such that the polarizing plate is on the liquid crystal light valve side. According to the above configuration, even if a slight phase difference occurs in the glass of the polarizing plate with glass, there is an effect that display unevenness is unlikely to occur. Because the image is formed between the first polarizer and the second polarizer, if the glass is placed outside it,
This is because an image is not disturbed even if an unnecessary phase difference occurs there. However, even when a phase difference of glass occurs outside the second polarizing plate, a slight contrast unevenness still occurs because a polarization dependent element such as a dichroic prism exists at this position. Also, even when a phase difference of glass occurs outside the first polarizing plate, the brightness is still slightly uneven due to the presence of the polarization converter. Therefore, even if the glass is placed outside the first polarizing plate and the second polarizing plate, it is still necessary to minimize the phase difference generated in the glass.

The liquid crystal projector according to the present invention is characterized in that a prism is provided between the second polarizing plate and the projection means, and the glass of the polarizing plate with glass is adhered to the prism. According to the above configuration, there is an effect that a polarizing plate with glass excellent in light resistance can be efficiently contained in a liquid crystal projector. Further, since there is no extra surface reflection, there is an effect that the displayed image is bright and has high contrast. Further, even if the glass to which the polarizing plate is attached is considerably thin, mechanical strength can be ensured, so that a polarizing plate with glass having more excellent light resistance can be obtained.

The liquid crystal projector according to claim 8, wherein at least one optical element other than the liquid crystal light valve is provided between the first polarizing plate and the second polarizing plate and at a position apart from any of the polarizing plates. It is characterized by having an anisotropic body. According to the above configuration, the optically anisotropic body can be arranged without causing deterioration due to light or heat, and as a result, there is an effect that image quality such as viewing angle and contrast can be improved.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a view showing the appearance of a polarizing plate with glass according to the first or second aspect of the present invention.

The structure will be described with reference to the drawings. FIG. 1 (a)
In the figure, 101 is a polarizing plate, and 102 is a glass plate.
A polarizing plate is adhered to the entire area or most of the area on one side of the glass plate via an adhesive. The glass plate may also serve another purpose such as a color filter. In FIG. 1B, reference numerals 103 and 104 denote polarizing plates, and reference numeral 105 denotes a prism (a type combining four prisms). A polarizing plate is attached to one to three surfaces of the prism via an adhesive. Also, in FIG.
06 is a polarizing plate and 107 is a plano-convex lens. A polarizing plate is attached to the plane side of the lens via an adhesive.

The polarizing plate used in the polarizing plate with glass of the present invention is based on a stretched film such as PVA as a base, and a polarizing element such as iodine or a dichroic dye is adsorbed and dispersed on the stretched film.
Such a laminate sandwiched between transparent support films is easy to use. However, from the viewpoint of light resistance, a type using a dichroic dye as a polarizing element is preferable.

As the glass, soda glass, borosilicate glass and the like have been conventionally used well, but these have a large average linear expansion coefficient of 32 to 92 × 10 ⁻⁷ / ° C. When such a glass is used, when strong light is applied from the right side (even from the left side) of the polarizing plate 201 with the glass 202 in FIG. This is because heat is generated due to light absorbed by the polarizing plate. When the polarizing plate 203 is arranged on the left side of the polarizing plate with glass in a crossed Nicols relationship and observed, this phase difference can be observed as light leakage at the four corners. Therefore, when such a polarizing plate with a glass is used in a liquid crystal device, contrast unevenness occurs at four corners of a screen.

Therefore, a polarizing plate with glass is prepared using glass plates having various average linear expansion coefficients, and irradiated with a 150 W high-pressure mercury lamp for 1 minute from the right side as shown in FIG. Was measured. The measurement place was the region where the transmittance was highest. The thickness of the glass plate is
It was unified to a general 0.7 mm. For each of the two polarizing plates, a high polarization type having a polarization degree of 99.99% or more was used. The result is shown in FIG.

In FIG. 3, the horizontal axis represents the average linear expansion coefficient, and the vertical axis represents the transmittance of leaked light standardized by the transmittance of glass and the polarizing plate. From this experimental result, it is clear that the glass having a smaller absolute value of the average linear expansion coefficient has a lower transmittance and is less likely to be uneven. In most cases, the average linear expansion coefficient has a positive value (that is, increases when warmed), but even if it is a negative value, the smaller the absolute value is, the smaller the transmittance is.
More preferred. Note that there are some variations in the experimental results. Most of them may be experimental errors, but it is considered that the difference in thermal conductivity, photoelastic coefficient, etc. depending on the glass also has an effect. However,
There is no doubt that the factor that most affects the transmittance of the leaked light is the average linear expansion coefficient.

In order to achieve a contrast of 1: 1000 required for a liquid crystal projector, at least this transmittance must be suppressed to 0.1% or less. Therefore, it is necessary to use glass having an absolute value of the average coefficient of linear expansion of 10 × 10 ⁻⁷ / ° C. or less. In an actual liquid crystal projector, there are other factors that lower the contrast, so that the absolute value of the average linear expansion coefficient is 3 × 10 ⁻⁷ / ° C. or less so that the transmittance is 0.02% or less with a margin. It is more desirable to use the above glass.

The absolute value of the average coefficient of linear expansion is 10 × 10 ⁻⁷
The glass having a temperature of not more than / ° C is, for example, quartz glass (5.5 × 10 ⁻⁷ / ° C) or 7913 manufactured by Corning Incorporated.
95% silicate glass (7.5 × 10 ⁻⁷ / ° C.), Neoceram N-0 from Nippon Electric Glass (−6 × 10 ⁻⁷ / ° C.)
Etc. The absolute value of the average linear expansion coefficient is 3 × 10
^As the glass having a temperature of ⁻⁷ / ° C. or less, for example, 7971 titanium silicate glass (0.3 × 10 ⁻⁷ /
° C).

When a polarizing plate with a glass was prepared using these glasses, in the experimental system shown in FIG. 2, light leakage at the four corners was improved to such an extent that it could not be visually recognized.

Example 2 FIG. 1A is a view showing the appearance of a polarizing plate with glass according to the third aspect of the present invention.

The structure will be described with reference to the drawings. FIG. 1 (a)
In the figure, 101 is a polarizing plate, and 102 is a glass plate.
A polarizing plate is adhered to the entire area or most of the area on one side of the glass plate via an adhesive. The glass plate may also serve another purpose such as a color filter. As the polarizing plate, a type using a dichroic dye as a polarizing element was used. Borosilicate glass, so-called Pyrex, was used as the glass plate. The average coefficient of linear expansion is 32.5 × 10
⁻⁷ / ° C.

The retardation generated in the glass of the polarizing plate with glass is affected by the thickness of the glass. Therefore, polarizing plates with glass were prepared using glass plates having various thicknesses, and irradiated with a 150 W high-pressure mercury lamp for 1 minute from the right side as shown in FIG. 2 to measure light leaking from the polarizing plate 203. The measurement place was the region where the transmittance was highest. Each of the two polarizing plates used was a high polarization type having a polarization degree of 99.99% or more. FIG. 4 shows the results.

In FIG. 4, the horizontal axis represents the glass thickness, and the vertical axis represents the transmittance of leaked light standardized by the transmittance of the glass and the polarizing plate. From this experimental result, it is clear that the smaller the thickness of the glass, the lower the transmittance and the less likely to be uneven.
In particular, when the glass thickness is sufficiently smaller than 1 mm, the transmittance is proportional to the glass thickness.

The glass thickness often used as an optical component is between 0.7 mm and 2.7 mm.
It was 0.5 mm or less.

In order to achieve a contrast of 1: 1000 required for a liquid crystal projector, at least this transmittance must be suppressed to 0.1% or less. It can be seen from FIG. 4 that it is necessary to use glass having a thickness of 0.1 mm or less for that purpose. However, such a thin glass plate has a large deflection and does not function as a support. To use it alone, a thickness of at least 0.2 mm is required. As long as the glass is 0.1 mm or more and 0.2 mm or less, it can be used by bonding it to another glass. However, it is difficult with glass of 0.1 mm or less.

Therefore, the method of reducing the thickness of the glass is not sufficiently effective when used alone, and it is desirable to use the method together with another method. For example, the average coefficient of linear expansion 20 × 1
By using glass having a temperature of 0 ⁻⁷ / ° C. or less, the transmittance can be suppressed to 0.1% or less even with a glass having a thickness of 0.4 mm. It is also effective to combine with the method described in the next embodiment.

(Embodiment 3) FIG. 5 is a view showing a cross section of a polarizing plate with a glass according to the fourth aspect of the present invention.

The structure will be described with reference to the drawings. FIG. 5 (a)
, 501 is a glass plate, 502 and 504 are polarizing plates, and 503 and 505 are adhesive layers. A polarizing plate is attached to all or most areas on both sides of the glass plate via an adhesive layer. Also, in FIG.
1 is a glass plate, 512 and 514 are polarizing plates, 516 is a retardation plate, 513, 515 and 517 are adhesive layers.

As the polarizing plate, a type using a dichroic dye as a polarizing element was used. Borosilicate glass, so-called Pyrex 0.7 mm thick glass, was used as the glass plate. Of course, if a glass having a small average linear expansion coefficient, such as quartz glass, or a glass having a thickness of less than 0.5 mm is used as the glass, the effect is increased accordingly. As the retardation plate, a half-wave plate made by stretching a polycarbonate or cycloolefin-based low dispersion film was used.

In the case of FIG. 5A, the absorption axes of the two polarizing plates 502 and 504 are always arranged parallel to each other. FIG.
In the case of (b), the two polarizing plates 512 and 514 are arranged such that the middle of the angle formed by the absorption axes of the absorption axes becomes the delay axis of the phase difference plate 516. When arranged in such an axial relationship, most of the light passing through one polarizing plate is transmitted through the other polarizing plate. In addition, the arrangement shown in FIG. 5B is very useful for a liquid crystal projector because the polarization axis can be freely rotated.

When the polarizing plate with glass having the above structure was irradiated with strong light, a slight phase difference occurred in the glass plate, and linearly polarized light was converted to elliptically polarized light. Some light was absorbed and corrected, resulting in the emission of perfectly linearly polarized light with slightly uneven brightness. This completely eliminated the light leaks at the four corners. Further, the unevenness in brightness was as small as 1% or less, so that it could not be visually recognized.

This configuration has a secondary effect. In addition to the four corner unevenness which is a problem in the present invention, the polarizing plate has a problem that the polarizing plate itself is exposed to strong light for a long period of time, so that the degree of polarization is reduced. However, in this configuration, only one polarizing plate is deteriorated by being exposed to strong light, and the other polarizing plate is hardly deteriorated. Therefore, even if one of the polarizing plates is deteriorated, the other can be compensated for, and as a result, the life of the polarizing plate is prolonged.

(Embodiment 4) FIG. 6 is a diagram showing the overall structure of a liquid crystal projector according to the fifth or sixth aspect of the present invention.

The structure and function will be described with reference to the drawings. FIG.
In, the light emitted from the light source lamp unit 601 passes through a uniform illumination & polarization conversion optical system 602 comprising an integrator lens and a polarization separation prism array, and becomes uniform linearly polarized light. Next, the light is bent at a right angle by the reflection mirror 603, and separated into red, green, and blue light beams by the red-green reflection dichroic mirror 604 and the green reflection dichroic mirror 606. Then, the reflecting mirrors 605, 607, 6
08, the condensing lens 609, the first polarizing plate 610, the liquid crystal light valve 611, the second polarizing plate 61 for each color.
2 and image formation is performed. The formed image of each color is combined with a color image by a color combining prism 613, and is enlarged and projected on a screen 615 via a projection lens unit 614.

The structure of a portion where image formation of each color is performed will be described in detail with reference to the drawings. In FIG. 7A, 701 is a condenser lens, 702 is a first polarizing plate, 703
Denotes a liquid crystal light valve, 704 denotes a second polarizing plate, and 705 denotes a color combining prism. The first polarizing plate 702 has a structure in which a polarizing plate 706 is attached to a glass plate 707, and the second polarizing plate 704 has a structure in which a polarizing plate 708 is attached to a glass plate 709. In each case, the polarizing plates 706 and 708 were arranged on the liquid crystal light valve side. This figure shows the structure of the portion that forms green light, but the portion that forms an image of blue light and red light has basically the same structure. Light enters from the left side and exits to the right side. Here, soda glass having a thickness of 1.1 mm (average coefficient of linear expansion = 81 × 10 ⁻⁷ / ° C.) was used for the glass plate 707.
09 is a 1.1 mm thick quartz glass (average coefficient of linear expansion =
5.5 × 10 ⁻⁷ / ° C.) or 0.4 mm thick Pyrex glass (average coefficient of linear expansion = 32.5 × 10 ⁻⁷⁾
/ ° C).

With this configuration, 1.1 m
When quartz glass having a thickness of m was used, there was no contrast unevenness at the four corners of the projected image, and even when Pyrex glass having a thickness of 0.4 mm was used, the unevenness was slight.
Therefore, it is possible to use a brighter lamp,
As a result, a bright liquid crystal projector was obtained. However, at this time, slight brightness unevenness occurred at the four corners.
This is due to a phase difference generated in the glass plate 707 constituting the first polarizing plate. Therefore, the glass plate 707 also has 1.1.
When the quartz glass having a thickness of mm or the Pyrex glass having a thickness of 0.4 mm was used, the unevenness in brightness was improved to a level that was not visible.

Next, another structure will be described. FIG.
In (b), 711 is a condenser lens, 712 is a first polarizing plate, 713 is a liquid crystal light valve, 714 is a second polarizing plate, and 715 is a color combining prism. The first polarizing plate 712 has a structure in which a polarizing plate 716 is attached to a glass plate 717, and the second polarizing plate 714 has a structure in which a polarizing plate 718 is attached to a glass plate 719. In this case, the glass plates 717 and 719 were arranged on the liquid crystal light valve side. With this configuration, the phase difference generated in the glass tends to adversely affect the display. Therefore, the glass plates 717 and 71 are set so that a phase difference is not induced in the glass plate as much as possible.
No. 9 is 797 made by Corning Co., Ltd. with a thickness of 0.3 mm.
1 Titanium silicate glass (average coefficient of linear expansion = 0.3 × 10
⁻⁷ / ° C.). With this configuration,
Neither contrast unevenness nor brightness unevenness occurred at the four corners of the projected image.

Another structure will be described. FIG.
8A, reference numeral 801 denotes a condenser lens, 802 denotes a first polarizing plate, 803 denotes a liquid crystal light valve, 804 denotes a second polarizing plate, and 805 denotes a color combining prism. However, the condensing lens and the color synthesizing prism are usually provided with crown glass (for example, BK7 glass manufactured by Schott Co.,
⁻⁷ / ° C.), but here, quartz glass (average linear expansion coefficient = 5.5 × 10 ⁻⁷ / ° C.) was used. With this configuration, there was no contrast unevenness or brightness unevenness at the four corners of the projected image. In addition, since there is no extra surface reflection as compared with the structure of FIG. 7, there is an effect that the displayed image is bright and has high contrast. In addition, such a simple configuration is advantageous in reducing the size of the liquid crystal projector.

Finally, another structure will be described. In FIG. 8B, reference numeral 811 denotes a condenser lens;
Denotes a first polarizing plate, 813 denotes a liquid crystal light valve, 814 denotes a second polarizing plate, and 815 denotes a color combining prism. The first polarizing plate 812 has a structure in which a polarizing plate 816 is attached to a glass plate 817. The second polarizing plate 814 has a structure in which a polarizing plate 818 is attached from the light incident side and a polarizing plate 819 and a half-wave plate 820 are attached to the glass plate 821 from the light emitting side. The absorption axes of the polarizing plates 814 and 819 are orthogonal to each other, and the slow axis of the half-wave plate
At an angle that makes a degree. Here, the glass plate 817 has a thickness of 0.1 mm.
7mm thick Pyrex glass (average coefficient of linear expansion = 3
2.5 × 10 ⁻⁷ / ° C.), but a 0.7 mm thick Neoceram N-0 glass (average coefficient of linear expansion = −6 × 10 ⁻⁷ / ° C.) was used for the glass plate 820. Was used. With this configuration, there was no contrast unevenness at the four corners of the projected image. However,
At this time, brightness unevenness slightly occurred at the four corners. The unevenness is caused by the 0.7 mm thick Neoceram N-0 glass plate 817.
By replacing the glass, it was improved to an invisible level.

(Embodiment 5) FIG. 9 is a diagram showing a main part of a liquid crystal projector according to a seventh embodiment of the present invention. The configuration of the entire liquid crystal projector is basically the same as the configuration of FIG. 6 described in the fourth embodiment.

In FIG. 9, reference numeral 901 denotes a condenser lens;
2 is a first polarizing plate, 903 is a liquid crystal light valve, 904 is a second polarizing plate, and 905 is a color combining prism. The first polarizing plate 902 has a structure in which a polarizing plate 906 is attached to a glass plate 907.
It is stuck on 1. The second polarizer 904 is a polarizer 908
Is attached to a glass plate 909, and the glass plate 9
The 09 side is attached to the color combining prism 905. Here, Pyrex glass having a thickness of 0.1 mm (average coefficient of linear expansion = 32.5 × 10 ⁻⁷ /
° C) was used. The condenser lens and the color combining prism are made of crown glass (average coefficient of linear expansion = 90 × 10 ⁻⁷ / ° C.). With this configuration, the contrast unevenness at the four corners of the projected image is significantly reduced. Also, a 0.3 mm thick 79 made by Corning Incorporated was placed on the glass plates 907 and 909.
13 95% silicate glass (average coefficient of linear expansion = 7.5 ×
10 ⁻⁷ / ° C.), no unevenness occurred.

(Embodiment 6) FIG. 10 shows an eighth embodiment of the present invention.
It is a figure showing the important section of the liquid crystal projector concerning the indicated invention. The configuration of the entire liquid crystal projector is basically the same as the configuration of FIG. 6 described in the fourth embodiment.

In FIG. 10A, 1001 is a condenser lens, 1002 is a first polarizing plate, 1003 is a first optical anisotropic body, 1004 is a liquid crystal light valve, 1005 is a second optical anisotropic body, 1006 Denotes a second polarizing plate, and 1007 denotes a color combining prism. The first polarizing plate 1002 is the polarizing plate 1
008 is attached to a glass plate 1009, the first optically anisotropic member 1003 is a structure in which a WV film 1010 made by Fuji Film is attached to the glass plate 1011, and the second optically anisotropic member 1005 is Fuji Film WV
The second polarizing plate 1006 has a structure in which a film 1012 is attached to a glass plate 1013, and the second polarizing plate 1006 has a structure in which a polarizing plate 1014 is attached to a glass plate 1015. WV film is T
A hybrid alignment discotic liquid crystal film having a function of widening the viewing angle of an N liquid crystal cell, the details of which are disclosed in JP-A-8-50206. Here, the glass plates 1009, 1011, 1013, 1015
Has a 0.5 mm thick Neoceram N-0 from NEC
Glass (average coefficient of linear expansion = −6 × 10 ⁻⁷ / ° C.) was used. With this configuration, there was no contrast unevenness at the four corners of the projected image. In addition, the heat generated by the polarizing plate did not affect the characteristics of the WV film. Further, by the effect of the WV film, the contrast of the projected image was improved from 1: 300 to 1: 450, and the unevenness due to the viewing angle characteristics of the liquid crystal was also improved.

Next, another structure will be described. FIG.
10B, reference numeral 1021 denotes a condenser lens, 1022 denotes a first polarizing plate, 1023 denotes a WV film as a first optically anisotropic body, 1024 denotes a liquid crystal light valve, and 1025 denotes a WV film as a second optically anisotropic body. The film 1026 is a second polarizing plate, and 1027 is a color combining prism. The first polarizing plate 1022 has a structure in which a polarizing plate 1028 is attached to a glass plate 1029, and the second polarizing plate 1026 has
30 is attached to a glass plate 1031. Here, a 0.5 mm thick quartz glass (average coefficient of linear expansion = 5.5 × 10 ⁻⁷ / ° C.) is used for the glass plates 1029 and 1031.
Was used. With this configuration, there was no contrast unevenness at the four corners of the projected image. In addition, the heat generated by the polarizing plate did not affect the characteristics of the WV film. Further, the effect of the WV film improved the contrast of the projected image and the unevenness caused by the viewing angle characteristics of the liquid crystal. In addition, since there is no extra surface reflection as compared with the structure of FIG. 10A, there is an effect that the displayed image is bright and has high contrast.

[0053]

As described above, according to the present invention, a polarizing plate with excellent light resistance is devised so that a phase difference does not occur in the glass even when the polarizing plate with glass is irradiated with strong light. Boards can be provided. Also, a bright liquid crystal projector using the polarizing plate with glass can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing an appearance of a polarizing plate with glass in Examples 1 and 2 of the present invention.

FIG. 2 is a diagram illustrating an experimental system according to Examples 1 and 2 of the present invention.

FIG. 3 is a view for explaining experimental results in Example 1 of the present invention, and is a view showing a relationship between an average linear expansion coefficient of glass of a polarizing plate with glass and a transmittance of leaked light.

FIG. 4 is a view for explaining experimental results in Example 2 of the present invention, and is a view showing a relationship between a glass thickness of a polarizing plate with glass and a transmittance of leaked light.

FIG. 5 is a diagram showing a cross section of a polarizing plate with glass in Example 3 of the present invention.

FIG. 6 is a diagram illustrating an overall structure of a liquid crystal projector according to Embodiments 4 to 6 of the present invention.

FIG. 7 is a diagram illustrating a structure of a portion where an image is formed by a liquid crystal projector according to a fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating a structure of a portion where an image is formed by a liquid crystal projector according to a fourth embodiment of the present invention.

FIG. 9 is a diagram illustrating a structure of a portion where an image is formed by a liquid crystal projector according to a fifth embodiment of the present invention.

FIG. 10 is a diagram illustrating a structure of a portion where an image is formed by a liquid crystal projector according to a sixth embodiment of the present invention.

FIG. 11 is a diagram showing a structure of a conventional liquid crystal projector.

[Explanation of symbols]

 101 polarizing plate 102 glass plate 103 polarizing plate 104 polarizing plate 105 prism 106 polarizing plate 107 lens 601 light source lamp unit 602 uniform illumination & polarization conversion optical system 603 reflecting mirror 604 red-green reflecting dichroic mirror 605 reflecting mirror 606 green reflecting dichroic mirror 607 reflection Mirror 608 Reflecting mirror 609 Condensing lens 610 First polarizer 611 Liquid crystal light valve 612 Second polarizer 613 Color combining prism 614 Projection lens unit 615 Screen

Claims (8)

[Claims] An absolute value of an average linear expansion coefficient is 10 × 10 ^−7.
A polarizing plate with glass, wherein a polarizing plate is attached to glass having a temperature of / ° C or lower. 2. The polarizing plate with glass according to claim 1, wherein the glass is any one of a glass plate, a prism and a lens. 3. A polarizing plate with glass, wherein a polarizing plate is attached to a glass plate having a thickness of 0.1 mm or more and 0.5 mm or less. 4. The other polarizing plate is disposed on the surface of the glass plate opposite to the surface on which the polarizing plate is attached, with another polarizing plate arranged so that most of the light transmitted through the polarizing plate is transmitted. The polarizing plate with glass according to claim 2 or 3, wherein the polarizing plate is attached. 5. A light source, a first polarizer for absorbing a specific polarization component of light emitted from the light source, a liquid crystal light valve for modulating light transmitted through the first polarizer, and the liquid crystal light valve. A second polarizing plate that absorbs a specific polarization component of light transmitted therethrough, and a liquid crystal projector including a projection unit that projects light transmitted through the second polarizing plate, wherein the two polarizing plates Claim 1 wherein at least the second polarizing plate is used.
A liquid crystal projector using the polarizing plate with glass according to any one of claims 1 to 4. 6. The liquid crystal projector according to claim 5, wherein said polarizing plate with glass is arranged so that the polarizing plate is on the liquid crystal light valve side. 7. A liquid crystal projector according to claim 6, wherein a prism is provided between said second polarizing plate and said projection means, and glass of said polarizing plate with glass is adhered to said prism. 8. At least one optically anisotropic body other than the liquid crystal light valve is provided between the first polarizing plate and the second polarizing plate and at a position apart from any of the polarizing plates. The liquid crystal projector according to claim 6, wherein: