JP2001201739A - Projection mode video display device and optical parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a projection mode video display device, to improve its brightness, to realize its high picture quality and to attain its high performance by realizing efficient heat radiation from optical parts with polarizing plates. SOLUTION: Each polarizing plate of the display element in the projection mode video display device has double plates construction. The polarization degree of the one out of the double plates closer to the light source is made lower than that of the other. Furthermore, the two polarizing plates are fixed on both sides of a light transmissive member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection device for projecting an image on a screen using a liquid crystal panel as a light valve element, for example, a projection device such as a liquid crystal projector device, a liquid crystal television, and a projection display device. The present invention relates to an image display device and optical components.

[0002]

2. Description of the Related Art In a projection type image display apparatus equipped with a transmissive liquid crystal display element, at least a pair of polarizing elements are always arranged before and after the liquid crystal display element, and a polarizing element on the light source side of the liquid crystal display element, that is, an incident side is a polarizer. The polarizing element on the side of the projection lens, that is, on the exit side, is used as an analyzer.

In order to previously convert the light incident on the polarizer into linearly polarized light, a polarization conversion element is generally used between the light source and the polarizer disposed immediately before the liquid crystal display element. Since the performance of the polarization conversion element is not sufficient, the polarization conversion element does not become perfect linearly polarized light, and absorbs light, that is, generates heat in the polarizer.

[0004] The function of the liquid crystal display element is to change the transmittance by controlling the polarization incident on the analyzer.
Light that does not pass is absorbed by the analyzer. In particular, when the screen is displayed in all black, the light incident on the analyzer is linearly polarized light parallel to the absorption axis of the polarizing plate, and the analyzer absorbs most of the light and generates a large amount of heat.

Conventionally, a polarizer disposed on the light source side of a liquid crystal display element and an analyzer disposed on the projection lens side include:
A method in which one polarizing plate is attached to one surface of a translucent member such as a glass substrate or a sapphire substrate, or the degree of polarization of the polarizing plate on the light source side with respect to the substrate is determined using the two substrates. The method of making it low was common.

[0006]

In order to maintain the life of the optical element and to achieve high image quality without color unevenness, it is essential to efficiently dissipate heat and make the in-plane temperature of the polarizing plate uniform. However, in recent years, with higher luminance and smaller size, it is difficult to solve these problems in the above configuration.

[0007] The polarizing plate is a heat source for both the polarizer and the analyzer and needs to be efficiently cooled. In a general method of bonding a polarizing plate to one side of glass, most of the heat radiation is from the polarizing plate surface because the thermal conductivity of the glass substrate is low. Some substrates use sapphire, which has high thermal conductivity to glass, but the effect is not sufficient. Therefore, a heat source can be dispersed by using two polarizing plates and using a polarizing plate having a low degree of polarization as a polarizing plate close to the light source. However, when these two sheets are bonded to different glass substrates, the size of the entire apparatus becomes large in order to secure a sufficient air path.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide means for achieving both miniaturization, high luminance, long life and high image quality.

[0009]

According to a first aspect of the present invention, there is provided a projection-type image display device comprising a light source, an illumination optical system, a liquid crystal display element, and a projection lens. The polarizer disposed on the light source side has a configuration using two polarizing plates, and of the two polarizing plates, the degree of polarization of the one closer to the light source is lower than the other, and the two polarizers are further arranged. The polarizing plate is configured to be fixed to both surfaces of the translucent member.

According to a second aspect of the present invention, in a projection type image display apparatus provided with a light source, an illumination optical system, a liquid crystal display element, and a projection lens, two analyzers arranged on the projection lens side of the liquid crystal display element are provided. A configuration in which a polarizing plate is used, and the degree of polarization of one of the two polarizing plates that is closer to the light source is lower than that of the other, and the two polarizing plates are fixed to both surfaces of a light transmitting member. And

According to a third aspect of the present invention, in a projection display apparatus including a light source, an illumination optical system, a liquid crystal display element, and a projection lens, a polarizer disposed on the light source side of the liquid crystal display element and the projection lens side And two analyzers, each having two polarizers, and of the two polarizers, the degree of polarization of the one closer to the light source is lower than the other, and the two polarizers are further arranged. The plate is fixed to both sides of the translucent member.

According to a fourth aspect of the present invention, in a projection display apparatus including a light source, an illumination optical system, a liquid crystal display element, and a projection lens, two polarizers are disposed on the light source side of the liquid crystal display element. The polarizing plate is configured to be fixed to both surfaces of the translucent member.

In the fifth invention, glass is used for the translucent member of the first to fourth inventions.

In a sixth aspect, sapphire is used for the light transmitting member of the first to fourth aspects.

According to a seventh aspect of the present invention, there is provided an optical component having a configuration using two polarizing plates, wherein one of the two polarizing plates has a lower degree of polarization than the other, and Are fixed to both surfaces of the translucent member.

By the above means, in the present invention, by fixing the polarizing plate on both surfaces of one glass, the surface area of the polarizing plate can be increased, that is, the cooling efficiency can be increased without increasing the size of the set.

On the other hand, since the heat generated by the polarizing plate is greater in the central part than in the peripheral part, temperature unevenness occurs in the plane. Thereby, transmittance unevenness occurs in the plane of the polarizing plate, which causes a difference in in-plane chromaticity, that is, color unevenness in a projected image. By using sapphire instead of glass as the substrate in the above configuration, the above-described means can eliminate in-plane temperature unevenness due to high thermal conductivity.

[0018]

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

FIG. 5 is an optical system configuration diagram showing an embodiment of the projection type liquid crystal display device according to the present invention.

In FIG. 5, the projection type liquid crystal display device includes:
There is a light source 1, and the light source 1 includes an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, a mercury xenon lamp,
It is a white lamp such as a halogen lamp. Light emitted from the light source 1 is reflected by a reflecting mirror 2 having a circular or polygonal exit aperture.
Is reflected by The light source 1 and the reflecting mirror 2 are collectively called a light source unit. The light emitted from the light source unit passes through the first array lens 3, the second array lens 4, and the polarization conversion element 5, and changes its direction to 9 at the total reflection mirror 6.
After being bent by 0 ° and separated into R (red), G (green), and B (blue) by dichroic mirror 7 and dichroic mirror 8, total reflection mirror 9 and total reflection mirror 1
0, the direction of the light beam is bent by the total reflection mirror 11, and is incident on the liquid crystal display element 12, the liquid crystal display element 13, and the liquid crystal display element 14, which are light valve elements corresponding to R, G, and B. The light that has passed through the R, G, and B liquid crystal display elements is recombined by the dichroic prism 15,
The light is projected on the screen by the projection lens 16.

FIG. 1 and FIG. 2 are configuration diagrams in the vicinity of a liquid crystal display device showing an embodiment of the present invention.

However, the liquid crystal display element 17 in FIGS. 1, 2, 3, and 4 corresponds to any of the liquid crystal display element 12, the liquid crystal display element 13, and the liquid crystal display element 14 in FIG. .

In the present invention, as shown in FIG. 1 and FIG. 2, the liquid crystal display element 17 is provided with a polarizing plate 18, 20, or 21, 22 bonded on both sides of the substrates 19, 22 on the incident side or the emitting side. The substrates 19 and 22 are made of glass or sapphire. Among them, the polarizing plate 18 bonded to the light source side of the substrate
Alternatively, by lowering the degree of polarization of 21, the calorific values of the two polarizing plates are dispersed.

In the conventional structure as shown in FIGS. 3 and 4, only one surface of the polarizing plate is exposed to air, whereas in the structure of the present invention, two surfaces are provided. The temperature can be kept low.

It is needless to say that the present invention can be applied to only one of the incident side and the outgoing side of the liquid crystal display element.

Further, as the substrates 19 and 22, inexpensive glass conventionally used can be used.
Further, when sapphire is used as a substrate, in-plane temperature unevenness can be eliminated due to its higher thermal conductivity as compared with glass.

[0027]

As described above, according to the present invention,
In a projection display apparatus including at least a light source, an illumination optical system, a liquid crystal display element, and a projection lens, a polarizer disposed on the light source side of the liquid crystal display element includes two polarizers, and the two polarizers are arranged. Since the degree of polarization of the plate closer to the light source is lower than the other, and the two polarizing plates are bonded to both sides of the translucent member, the polarizer can be used without increasing the size of the set. It is possible to increase the surface area of the polarizing plate, that is, to increase the cooling efficiency.

According to the present invention, in a projection display apparatus comprising at least a light source, an illumination optical system, a liquid crystal display element, and a projection lens, an analyzer disposed on the projection lens side of the liquid crystal display element is polarized. Because the two polarizing plates are used, and the degree of polarization of one of the two polarizing plates closer to the light source is lower than the other, and the two polarizing plates are bonded to both surfaces of the light transmitting member. In addition, it is possible to increase the surface area of the polarizing plate of the analyzer, that is, to increase the cooling efficiency without increasing the size of the set.

Further, according to the present invention, in a projection display apparatus comprising at least a light source, an illumination optical system, a liquid crystal display element, and a projection lens, a polarizer disposed on the light source side of the liquid crystal display element and the projection The analyzer arranged on the lens side is composed of two polarizing plates, respectively, and the polarization degree of the one of the two polarizing plates that is closer to the light source is lower than the other, and the two polarizing plates are transmitted through the two polarizing plates. Since the optical members are bonded to both sides, it is possible to increase the surface area of the polarizing plate of the polarizer and the analyzer, that is, to increase the cooling efficiency without increasing the size of the set.

Further, according to the present invention, since glass is used for the translucent member, an inexpensive glass substrate can be used as in the prior art.

Further, according to the present invention, since sapphire is used for the translucent member, in-plane temperature unevenness can be eliminated due to its higher thermal conductivity than glass. Thereby, the transmittance unevenness in the plane of the polarizing plate can be eliminated, and the in-plane chromaticity difference, that is, the color unevenness in the projected image can be eliminated.

According to the present invention, there is provided an optical component comprising two polarizing plates, wherein one of the two polarizing plates has a lower degree of polarization than the other, and the two polarizing plates are further provided. The optical parts bonded to both sides of the translucent member are used not only for the projection type image display device but also for the polarizer and analyzer generally used for other devices. This has the effect of increasing the surface area of the polarizing plate of the polarizer and the analyzer, that is, increasing the efficiency of cooling without increasing the size of the polarizer.

[Brief description of the drawings]

FIG. 1 is a schematic top view showing a part of one embodiment of a projection type liquid crystal display device of the present invention.

FIG. 2 is a schematic top view showing a part of one embodiment of the projection type liquid crystal display device of the present invention.

FIG. 3 is a schematic top view showing a part of one embodiment of a conventional projection type liquid crystal display device.

FIG. 4 is a schematic top view showing a part of one embodiment of a conventional projection type liquid crystal display device.

FIG. 5 is a schematic top view showing an embodiment of the projection type liquid crystal display device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Reflection mirror, 3 ... First array lens, 4 ... Second array lens, 5 ... Polarization conversion element, 6 ... Total reflection mirror, 7 ... Dichroic mirror, 8 ... Dichroic mirror, 9 ... Total reflection mirror , 10 ... Total reflection mirror, 11 ...
Total reflection mirror, 12: liquid crystal display element, 13: liquid crystal display element, 14: liquid crystal display element, 15: dichroic prism, 16: projection lens, 17: liquid crystal display element, 18: polarizing plate, 19: substrate, 20: polarized light Plate, 21 ... polarizing plate, 22
... substrate, 23 ... polarizer, 24 ... substrate, 25 ... polarizer, 2
6 ... polarizer, 27 ... substrate, 28 ... polarizer ASS'Y, 29 ...
Polarizing plate ASS'Y, 30 ... Polarizing plate ASS'Y, 31 ... Polarizing plate ASS'Y
Y, 32: polarizing plate ASS'Y, 33: polarizing plate ASS'Y.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Nakajima 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Digital Media System Division, Hitachi, Ltd. 292 Hitachi Media, Ltd. Digital Media Systems Division F-term (reference) 2H088 EA12 HA01 HA13 HA18 HA21 HA24 MA06 MA20 2H091 FA05X FA08X FA08Z FA26X FA41Z GA01 LA18 LA30 MA07

Claims (7)

[Claims] 1. A projection-type image display device comprising a light source, an illumination optical system, a liquid crystal display element, and a projection lens, wherein a polarizer disposed on the light source side of the liquid crystal display element has two polarizers.
A configuration using two polarizing plates, and of the two polarizing plates, the degree of polarization of the one closer to the light source is lower than the other, and
Further, the two polarizing plates are fixed to both surfaces of the translucent member. 2. A projection type video display apparatus comprising a light source, an illumination optical system, a liquid crystal display element, and a projection lens, wherein an analyzer arranged on the projection lens side of the liquid crystal display element uses two polarizing plates. Wherein the degree of polarization of one of the two polarizing plates closer to the light source is lower than that of the other, and the two polarizing plates are fixed to both surfaces of the light transmitting member. Projection type video display device. 3. A projection display apparatus comprising a light source, an illumination optical system, a liquid crystal display element, and a projection lens, wherein a polarizer disposed on the light source side of the liquid crystal display element and a projection lens side. The analyzer is configured to use two polarizing plates, and of the two polarizing plates, the one near the light source has a lower degree of polarization with respect to the other, and furthermore, the two polarizing plates transmit light. A projection-type image display device, wherein the projection-type image display device is fixed to both surfaces of a conductive member. 4. A projection display apparatus comprising a light source, an illumination optical system, a liquid crystal display element, and a projection lens, wherein a polarizer arranged on the light source side of the liquid crystal display element is provided.
A projection-type image display device, wherein two polarizing plates are fixed to both surfaces of a translucent member. 5. The method according to claim 1, wherein said light-transmitting member is made of glass.
5. The projection-type image display device according to any one of items 1 to 4. 6. The projection type video display according to claim 1, wherein sapphire is used for said translucent member. 7. An optical component comprising two polarizing plates, wherein one of the two polarizing plates has a lower degree of polarization than the other, and furthermore, the two polarizing plates are formed of a light-transmitting member. Optical parts characterized by being fixed on both sides.