JP2000171900A - Photoirradiation device and liquid crystal projection system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoirradiation device for the case temperature elevation is particularly desired to be averted while necessitating high luminance, and a liquid crystal projection system which does not degrade luminance and does not require the interruption of projection due to temperature elevation. SOLUTION: This liquid crystal projection system is provided with a IR reflection filter 2 which allows the transmission of visible light of the light emitted from a light source 1, such as a xenon lamp, and reflects IR transversely from the passage of the light described above in the passage and is provided with a liquid crystal panel 3 on the passage of the visible light transmitted through the filter 2. The image formed by the light past the liquid crystal panel 3 is condensed to a macro-projection lens 5 via a condenser lens 4 consisting of, for example, a Fresnel lens, and is enlarged by the projection lens 5 and is projected to a screen, etc. An IR absorber 6 is disposed in the progression direction of the IR reflected by the filter 2 and a blasting means 7 for cooling the same is disposed near the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a light irradiation device such as a liquid crystal projector which requires high luminance and does not want to raise the temperature, and a liquid crystal projection system using the same. More specifically, the present invention relates to a light irradiation device that can irradiate high-intensity visible light to a portion that is not resistant to heat, such as a liquid crystal panel, and a liquid crystal projection system using the same.

[0002]

2. Description of the Related Art A conventional liquid crystal projection system is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-183479, and as shown in FIG. 4, a simplified diagram of a light source 101 comprising a high voltage arc lamp such as a xenon lamp. An infrared absorption filter 102 is arranged in a light path, and visible light having absorbed infrared rays is incident on the liquid crystal panel 103, and the liquid crystal panel 103 controls on / off of each pixel to transmit light forming a desired image. The light transmitted through the liquid crystal panel 103 is condensed by a condenser lens 104 and projected on a screen (not shown) by a projection lens 105.

[0003] In order to clearly project on a screen even in a bright place with this liquid crystal projection system, it is necessary to transmit strong light through the liquid crystal panel.
As described above, a high-luminance arc lamp such as a xenon lamp is used. However, when such a high-intensity light source is used, heat is also generated in a very large amount, and the temperature around the light source and the light projection portion increases. On the other hand, when the temperature of the liquid crystal panel rises excessively, the display contrast is reduced and the life of the liquid crystal is shortened. Therefore, as shown in FIG. 4, the infrared absorption filter 102 is provided in the passage from the light source 101, and the liquid crystal panel 103 is also provided with a cooling device 103a using a transparent cooling medium such as ethylene glycol.

[0004]

As described above, in the conventional liquid crystal projection system, the liquid crystal panel is irradiated with light through the infrared absorption filter so that the heat of the light source does not reach the liquid crystal panel. In the absorption filter, the liquid crystal panel is also irradiated with the infrared rays without being able to sufficiently absorb the infrared rays. Furthermore, the infrared absorption filter has a problem that when it absorbs infrared rays, the temperature of the infrared absorption filter itself rises, and the increased heat is directly transmitted to the liquid crystal panel as radiant heat, thereby heating the liquid crystal panel. Therefore, the liquid crystal panel must be provided with the special cooling device as described above, and the temperature rise still cannot be avoided. If the temperature rises to some extent, the operation must be stopped and the temperature must be lowered. There is a problem.

Further, the infrared absorption filter also has a problem that the transmittance of visible light is reduced, so that the transmitted light is weakened, and a light source having higher luminance must be used, which further increases the temperature.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a light irradiating device which requires high luminance and does not particularly want to raise the temperature.

Another object of the present invention is to provide a liquid crystal projection system that does not lower the luminance and does not need to interrupt the projection due to a rise in temperature.

[0008]

The light irradiation device according to the present invention comprises:
A high-intensity discharge lamp, an infrared reflection filter that is provided in a passage of light emitted from the high-intensity discharge lamp, transmits visible light of the irradiated light, and reflects infrared light from the passage laterally; And an infrared absorber provided so as to absorb the infrared rays in the traveling direction of the infrared rays.

Here, a high-intensity discharge lamp means a light source such as a xenon lamp or a halide lamp which emits large light by arc discharge at high pressure.

[0010] With this configuration, the infrared ray, which is a heat source (heat ray), is transferred from the light irradiation path to another place and absorbed by the filter, so that other components such as a liquid crystal panel interposed in the light irradiation path can be used. Without increasing the temperature,
Only visible light can be supplied with a large luminance.

A liquid crystal projection system according to the present invention is provided in a high-luminance light source and a passage for light emitted from the high-luminance light source, transmits visible light of the emitted light, and reflects infrared light from the passage laterally. An infrared reflection filter, a liquid crystal panel provided in a path of visible light transmitted through the filter, an enlarged projection lens for enlarging and projecting an image formed by light passing through the liquid crystal panel, and reflection by the filter film. An infrared absorber provided so as to absorb the infrared light in the traveling direction of the infrared light, and a blowing means for cooling the infrared absorber.

According to this structure, the heat source is reflected by the infrared reflection filter in a direction different from the light irradiation path, is absorbed by the light absorber at a remote location, and is cooled by the blowing means. No indirect heating. In addition, since the separation accuracy between infrared light and visible light by the filter film can be extremely high, the infrared light is hardly transmitted and the intensity of the visible light is not attenuated. It does not raise the temperature.

The visible light transmitted through the filter is red, green,
A dichroic mirror is provided so as to be separated into three primary colors of blue, and the three liquid crystal panels are composed of three liquid crystal panels. The three liquid crystal panels are so arranged that the light of the three primary colors respectively enters the three liquid crystal panels. Is provided, and means for combining the outputs of the three liquid crystal panels and condensing the output on the magnifying projection lens is provided, so that color projection can be performed without using a color filter on the liquid crystal panel. .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a light irradiation device and a liquid crystal projection system using the same according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, an embodiment of the liquid crystal projection system according to the present invention is provided in a path of light emitted from a light source 1 composed of a high-intensity discharge lamp such as a xenon arc lamp. An infrared reflection filter 2 that transmits visible light of the irradiated light and reflects infrared light laterally from the passage is provided, and a liquid crystal panel 3 is provided in a passage of the visible light transmitted through the filter 2. Then, an image formed by the light passing through the liquid crystal panel 3 is condensed on an enlarged projection lens 5 via a condenser lens 4 composed of, for example, a Fresnel lens, and is enlarged by the projection lens 5 to a screen (not shown). It has a structure to project. In the traveling direction of the infrared light reflected by the filter 2 provided according to the present invention, an infrared absorber 6 is provided so as to absorb the infrared light, and a blowing means 7 for cooling the infrared absorber 6 is provided in the vicinity thereof. .

Further, the light irradiation apparatus of the present invention uses the light source 1
And a filter 2 and an infrared absorber 6, not only for irradiating the liquid crystal panel with high-luminance visible light, but also for only visible light from which infrared rays (heat rays) have been similarly removed, such as a slide projector or an OHP. It can be effectively used when it is necessary to irradiate cool high-brightness light.

As shown in FIGS. 2A and 2B, the infrared reflection filter 2 that reflects infrared light and transmits visible light is provided with a first dielectric material having a low refractive index, such as MgF ₂ or SiO _2. Body film 2a, ZnSe, ZnS, TiO ₂ ,
ZnS in which high refractive index second dielectric films 2b such as Ta ₂ O ₅ are alternately laminated on a transparent glass or the like in this order.
/ MgF ₂ , TiO ₂ / SiO ₂ , Ta ₂ O ₅ / SiO
_A device utilizing multiple optical interference by a multilayer film of a dielectric film such as ₂ can be used. Also, a dielectric material 2 such as Ta ₂ O ₅ / Ag / Ta ₂ O ₅ shown in FIG.
It can also be formed of a laminated structure of c / metal 2d / dielectric 2c or a metal material such as porous chromium. When an infrared reflection filter is formed of a dielectric film or a multilayer film composed of a dielectric film and a metal film, the thickness of each film is λ / (4
n) (λ is the wavelength of the light to be reflected, and n is the refractive index thereof). By examining the light emission characteristics of the light source, it is possible to determine in which wavelength region of the infrared light is emitted. Therefore, by forming a laminated film that reflects at various wavelengths so as to reflect in that wavelength region, it is almost desirable. Can be reflected.

The above-mentioned TiO ₂ (refractive index: 2.6) / SiO
₂ (refractive index: 1.4) must be formed by a sputtering method, but has an advantage that it has excellent heat resistance and can be used without problems even when used at high temperatures. ZnS / MgF ₂ is inferior in heat resistance, but can be easily formed by vacuum evaporation. Other film forming methods include a laser ablation method, a CVD method, a sol-gel method,
A method such as a spray method can be used.

As the light source 1, a xenon arc lamp,
A high-intensity discharge lamp such as a halide lamp, a halogen lamp, a high-pressure sodium lamp, and a high-pressure mercury lamp is used. As shown in FIG. 1, the light source 1 has a reflecting mirror 1a.
, And is configured to reflect the light traveling backward to the front, so that the light emitted from the light source 1 can be used without waste, which is very efficient. It is desirable that a cold mirror (not shown) be provided on the inner surface of the reflecting mirror 1a so as to absorb infrared rays and transmit only visible light to the liquid crystal panel 3 side. However, even in this case, the light traveling directly forward from the lamp contains infrared rays, and if the cold mirror is not sufficiently cooled, heat is radiated and travels forward, so that the heat rays cannot be completely removed.

The liquid crystal panel 3 has a structure in which a liquid crystal layer is sandwiched between two transparent substrates in each of which a transparent electrode is formed in a matrix, and a polarizing plate is provided on both sides, similarly to a normal liquid crystal panel. You. Then, by controlling the transmission of light of each pixel by controlling the application of a voltage to each pixel, a desired image can be displayed. In the liquid crystal panel 3, each pixel is represented by red (R), green (G), and blue (B).
The color display can be performed by forming the color filters corresponding to the color filters described above and controlling each pixel.

The condenser lens 4 is composed of a convex lens for condensing an image coming out of the liquid crystal panel 3 as parallel light onto the magnifying projection lens 5, and a Fresnel lens is used to reduce its thickness. . The condensing lens 4 is for condensing the light transmitted through the liquid crystal panel 3 on the magnifying projection lens 5, and may be provided in a stage preceding the liquid crystal panel 3. The magnifying projection lens 5 is configured so that the condensed image of the liquid crystal panel 3 is magnified and projected on a screen or the like, and the position of the magnifying liquid crystal panel 3 can be adjusted so as to focus on the screen by slightly moving the position.

The infrared absorber 6 is made of, for example, a filter formed by blackening a porous foam metal, and is provided so as to face the traveling direction of the infrared light reflected by the infrared reflection filter 2. In the example shown in FIG. 1, the infrared reflection filter 2 is provided so as to be approximately 45 ° with respect to the optical path from the light source 1, and is reflected substantially at right angles to the optical path from the light source 1. An infrared absorber 6 is attached to the side wall of the body. The blackened metal foam filter is, for example, a mesh-like filter whose surface is blackened by forming many zigzag slits on nickel, copper, or two or more aluminum plates, and has a porosity of 50%.
Although it is as large as about 80% and the temperature rises by effectively absorbing infrared rays, it has a porosity that does not hinder exhaust air, so that heat can be easily exhausted by blowing air. The combined use of a filter made of sponge linear metal having a porosity of about 98% at the maximum can further improve the effects of infrared absorption and exhaust heat. As the infrared absorber 6, such a porous ceramic filter or the like can be used.

The heat absorbed by the infrared absorbing member 6 is blown by a blowing means 7 provided in the vicinity thereof, or the heat for cooling the light source 1 or the like is exhausted through the infrared absorbing member 6, The porous part of the filter is ventilated and cooled, so no heat builds up.

According to the liquid crystal projection system of this configuration, more than half of the light from the light source 1 is infrared rays and heat rays, but most of the heat rays are removed by the cold mirror of the light source 1 and the infrared reflection filter 2, Almost only visible light enters the liquid crystal panel 3. Since the removed heat rays are cooled at a portion of the light source 1 or the infrared absorber 6 away from the liquid crystal panel 3, heat is not radiated to the liquid crystal panel 3 and the temperature of the liquid crystal panel rises to display. Eliminates the need to interrupt until the properties are degraded or the temperature drops. Moreover, since there is almost no heat rays, even if a color filter is provided on the liquid crystal panel, the color filter does not absorb heat and does not rise in temperature, which is convenient for displaying color liquid crystal. . As a result, a desired image can be displayed in color on a screen by driving a personal computer or the like.

As described above, since most of the heat rays of the light incident on the liquid crystal panel are removed, even a liquid crystal panel having a color filter can be displayed on a screen in color by light from a high-luminance light source without any problem. However, as shown in FIG. 3, a color display can also be performed by using a dichroic mirror and a dichroic prism and using liquid crystal panels for each of red, green and blue.

In FIG. 3, the above-mentioned infrared reflection filter 2 is first disposed in the optical path of light from the light source 1, and infrared rays are reflected from the optical path to the side. Then, only the visible light is transmitted, only the blue light is reflected by the first dichroic mirror 81, and the other green and red lights are transmitted. The reflected blue light is totally reflected by the first mirror 91 and is incident on the first liquid crystal panel 31 for blue provided on one side surface of the cubic dichroic prism 85. The transmitted red and green lights are configured such that only the green light is reflected by the second dichroic mirror 82 and is incident on the second liquid crystal panel 32 for green provided on the other side surface of the dichroic prism 85. ing. The red light transmitted through the second dichroic mirror 82 is totally reflected by the second and third mirrors 92 and 93, and enters the third liquid crystal panel 33 for red provided on the other side surface of the dichroic prism 85. It is configured to be. As a result, high-luminance light of only red enters the third liquid crystal panel 33 for red, high-luminance light of only green enters the second liquid crystal panel 32 for green, and High-intensity light of only blue is incident on the first liquid crystal panel 31, and the respective liquid crystal panels 31, 32, and 33 are driven in conjunction with each other to display three primary colors of red, green, and blue in a dichroic prism. The light is combined into a full color by the light 85 and enters the magnifying projection lens 5. Although the condenser lens is omitted, it can be provided on the emission side of the dichroic prism 85 or on the front of each liquid crystal panel.

[0027]

According to the present invention, even if a light irradiating device using a high-pressure arc lamp such as a very high-brightness xenon lamp as a light source as used in a liquid crystal projector or the like is used,
Since most of the heat rays are removed, the temperature of the liquid crystal panel and the like does not rise. Therefore, the projection is not interrupted until the temperature is lowered during use, and the liquid crystal material is not deteriorated due to heat, and the maintenance of the liquid crystal projector becomes very easy.

Further, according to the light irradiation apparatus of the present invention, since a heat ray is almost removed while using a light source having a very high luminance, not only a liquid crystal projector but also a wide range of fields such as a slide projector and an OHP can be used. It can be used as a high-intensity and cold light irradiation device.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of a liquid crystal projection system of the present invention.

FIG. 2 is an explanatory sectional view of an example of the infrared reflection filter of FIG. 1;

FIG. 3 is an explanatory diagram of another embodiment of the liquid crystal projection system of the present invention.

FIG. 4 is a diagram illustrating the configuration of a conventional liquid crystal projection system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source 2 infrared reflection filter 3 liquid crystal panel 5 magnifying projection lens 6 infrared absorber 7 blowing means

Claims (3)

[Claims] A high-intensity light source; and an infrared reflection filter provided in a path of light emitted from the high-intensity light source and transmitting visible light of the emitted light and reflecting infrared light from the path laterally; A light irradiating device comprising: an infrared absorber provided to absorb the infrared light in the traveling direction of the reflected infrared light. 2. A high-intensity discharge lamp and an infrared reflection filter provided in a path of light emitted from the high-intensity discharge lamp and transmitting visible light of the emitted light and reflecting infrared rays from the path laterally. A liquid crystal panel provided in a path of visible light transmitted through the filter, an enlarged projection lens for enlarging and projecting an image formed by light transmitted through the liquid crystal panel, and a traveling direction of infrared light reflected by the filter An infrared absorber provided to absorb the infrared light,
A liquid crystal projection system comprising: a blower for cooling the infrared absorber. 3. The visible light transmitted through the filter is red,
A dichroic mirror is provided so as to be separated into three primary colors of green and blue, and the liquid crystal panel comprises three liquid crystal panels.
The three liquid crystal panels are provided so that light of the primary colors is incident on the three liquid crystal panels, respectively, and means for combining the outputs of the three liquid crystal panels and condensing the light on the magnifying projection lens is provided. 3. The liquid crystal projection system according to claim 2, wherein the liquid crystal projection system is provided.