JPH05158152A - Illumination device - Google Patents

Abstract

PURPOSE:To prevent the temperature of a heat absorbing filter from rising even when it absorbs much heat and to effectively prevent the temperature of an optical factor on and after the filter from rising by making liquid in a transparent container circulate and making a light incident surface and a light emitting surface plane-parallel. CONSTITUTION:The heat absorbing filter 4 is plane-parallel and almost vertically maintained with respect to the optical axis L1 of an illumination system. Then, a heat ray (infrared ray) among a luminous flux emitted from a white color light source 2 is absorbed by the filter 4 and radiated to the liquid 3 at a temperature rising time. The incident surface 11a and the emitting surface 11b of the transparent container 11 are mutually plane-parallel and a heat radiation part 19 is provided at the upper part of the container 11. Then, the heat of the liquid 3 is radiated to the outside by increasing the surface area thereof. The radiation part 19 at the upper part of the container 11 is cooled by a fan 18. By such constitution, the heat is radiated to the outside by making the liquid 3 whose temperature rises circulate and the filter 4 whose temperature becomes high is effectively cooled in the container 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device and, for example, to an illuminating device suitable for illuminating an image displayed on a liquid crystal as an object to be illuminated with a light beam from a high-intensity light source and projecting it on a screen surface. It is a thing.

[0002]

2. Description of the Related Art Conventionally, in a lighting device in a projector or the like, when a projection object (irradiation object) is illuminated with a light flux from a light source, the light flux from the light source is illuminated with a light flux with a heat ray cut through a heat absorption filter. I am trying to do it.

For example, a liquid crystal projector for projecting an image displayed on a liquid crystal often uses a halogen lamp or the like having a high output as a light source. Therefore, the heat (heat rays) radiated from the light source may raise the temperature of the liquid crystal panel and change its function, or the optical properties of the total reflection mirror, dichroic mirror, and projection system may change.

For this reason, for example, a heat absorption filter having a predetermined thickness is arranged between the light source and the dichroic mirror to absorb the heat rays and prevent the temperature of the optical element from increasing thereafter.

[0005]

Generally, if a heat absorption filter is used, heat can be absorbed from the light flux emitted from the light source, and hence the heat incident on the optical elements thereafter can be reduced.

However, when the heat absorbing filter absorbs a large amount of heat, the temperature of the heat absorbing filter itself becomes too high, the heat absorbing filter is cracked, and the optical characteristics are changed, so that the function as the heat absorbing filter deteriorates. There was a problem.

According to the present invention, when a high-power light source is used to illuminate an object to be illuminated, the temperature of the heat absorption filter does not rise even if the heat absorption filter absorbs much heat. It is an object of the present invention to provide a lighting device capable of effectively preventing the temperature rise of the optical element.

[0008]

In the illuminating device of the present invention, when the luminous flux from the light source means is guided to the irradiated object through the heat absorption filter and the condenser lens to illuminate the object, the heat absorption filter is filled with a liquid. The transparent container is immersed in the liquid, and the heat absorbed by the heat absorption filter is released to the liquid.

In particular, the present invention is characterized in that the liquid in the transparent container is circulated, and that the light entrance surface and the light exit surface of the transparent container are parallel planes.

[0010]

FIG. 1 is a schematic view of the essential parts of a first embodiment of the present invention when the illumination device of the present invention is applied to a color liquid crystal projection for projecting an image displayed on a color liquid crystal.

In the figure, reference numeral 2 denotes a light source means, which comprises a white light source such as a halogen lamp. Reference numeral 2 denotes a concave mirror, which reflects the light flux emitted from the white light source 2 arranged at the center of its curvature, returns it to the original optical path, and guides it to the condenser lens 5 side described later. Reference numeral 4 denotes a heat absorption filter, which is immersed in the transparent container 11 containing the liquid 3.

The heat absorption filter 4 is composed of a plane parallel plate and is maintained substantially perpendicular to the optical axis L1 of the illumination system. The heat absorption filter 4 absorbs heat rays (infrared rays) in the light flux emitted from the white light source 2, and when the temperature rises, the heat is emitted to the liquid 3.

The entrance surface 11a and the exit surface 11 of the transparent container 11
b is a plane parallel to each other. A heat radiating portion (fin) 19 is provided on the upper part of the transparent container 11 to increase the surface area and radiate the heat of the liquid 3 to the outside.

Reference numeral 18 denotes a fan, which cools the heat radiating portion 19 above the transparent container 11. With such a configuration, the transparent container 11 convects the liquid 3 whose temperature has risen to release heat to the outside and effectively cools the heat absorption filter 4 that has reached a high temperature.

Reference numeral 5 denotes a condenser lens, which emits the light flux passing through the heat absorption filter 4 and the liquid 3 in the transparent container 11 as a substantially parallel light flux.

Reference numerals 12a, 12b and 12c are liquid crystal display elements for red, green and blue, respectively. Reference numerals 13a and 13b are reflection mirrors, 14 is a red reflection dichroic mirror, and illuminates the red liquid crystal display element 12a through the reflection mirror 13a. A green reflection dichroic mirror 15 illuminates the liquid crystal display element 12b for green.

The liquid crystal display element 12c for blue includes a red reflection dichroic mirror 14 and a green reflection dichroic mirror 15.
It is illuminated with blue light that has passed through. Reference numeral 16 is a blue reflection dichroic mirror. Reference numeral 17 is a projection lens.

In this embodiment, the white light from the white light source 2 is condensed by the condenser lens 5 as white light from which heat is removed through the liquid 3 in the transparent container 11 and the heat absorption filter 4.
Then, the white light from the condenser lens 5 is separated into red, green, and blue color lights by the dichroic mirrors (14, 15, 16), and these red, green, and blue color lights are used for red, green, and blue, respectively. Illuminates the liquid crystal display elements (12a, 12b, 12c),
Liquid crystal display elements (12a, 12a) based on these color lights
The images (b, 12c) are projected on the screen surface (not shown) by the projection lens 17 to obtain a color image.

In this embodiment, with such a structure, even when the high-intensity white light source 2 is used, the heat absorption filter 4 prevents the temperature of the heat absorption filter from increasing in temperature when the heat is absorbed, and effectively heats the heat. Absorbed into.

As a result, the condenser lens 5 after the heat absorption filter 4 and the dichroic mirror (14, 15, 1)
6), and liquid crystal display elements (12a, 12b, 12c)
Good optical performance is maintained while preventing the temperature rise of optical elements such as.

FIG. 2 is a schematic view of a main part in the vicinity of the transparent container 11 of the lighting device of the present invention.

In this embodiment, a pipe-shaped running water portion 22 is provided on the upper portion of the transparent container 11. Then, the liquid 21 is forcedly circulated through the flowing water portion 22 by the pump 21 provided in a part of the transparent container 11. As a result, heat is released from the surface of the running water portion 22 to effectively cool the liquid 3 in the transparent container 11.

[0023]

According to the present invention, when a high-power light source is used to illuminate an object to be illuminated by configuring each element as described above, even if the heat absorption filter absorbs a large amount of heat, It is possible to achieve an illumination device in which the temperature of the absorption filter is prevented from increasing and the temperature rise of the optical elements after the heat absorption filter can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment when a lighting device of the present invention is applied to a color liquid crystal projector.

FIG. 2 is a schematic view of a main part of another embodiment of the transparent container used in the lighting device of the present invention.

[Explanation of symbols]

 1 Concave Mirror 2 Light Source Means 3 Liquid 4 Heat Absorption Filter 5 Condenser Lens 11 Transparent Container 12a, 12b, 12c Liquid Crystal Display Element 13a, 13b Reflection Mirror 14 Red Reflection Dichroic Mirror 15 Green Reflection Dichroic Mirror 16 Blue Reflection Dichroic Mirror 17 Projection Lens 18 Fan 19 fin

Claims (3)

[Claims] 1. When the light flux from the light source means is guided to the object to be illuminated through a heat absorption filter and a condenser lens for illumination, the heat absorption filter is immersed in a transparent container containing a liquid,
An illumination device, wherein heat absorbed by the heat absorption filter is released to the liquid. 2. The lighting device according to claim 1, wherein the liquid in the transparent container is circulated. 3. The illumination device according to claim 1, wherein the light incident surface and the light exit surface of the transparent container are parallel planes.