JPH0498755A - Metal halide lamp - Google Patents

Abstract

PURPOSE:To compensate for the tendency of shortage in red coloring without changing the luminous intensity distribution of other types of color, and obtain more desirable white coloring by applying the constitution wherein a fluorescent material is applied to the inner wall of a tube bulb 12 sealing a luminous tube for intensifying red coloring, and the fluorescent material on the aforesaid inner wall is excited for red coloring with light from the luminous tube. CONSTITUTION:A fluorescent material 19 capable of red coloring, such as a red phosphor used for a color cathode-ray tube, is applied to a part of the inner wall of a tube bulb 12, for example, to an area within a range from a front in the tube bulb 12 to a position immediately below a luminous tube 13. In the operation of a metal halide lamp 11, the luminous tube 13 turns into ordinary luminous state, and the luminosity thereof (or near ultraviolet radiation) causes the excitation and red coloring of the fluorescent material (red phosphor) 19 applied to a part of the inner wall of the tube bulb 12. As a result, red coloring liable to be insufficient can compensated for without changing the luminous intensity distribution of other types of color. Also, the whole luminosity of the metal halide lamp 11 becomes more desirable white. Consequently, when this metal halide lamp 11 is used as a white color source 2 for a liquid crystal projector 11, a problem related to red coloring shortage is solved, and a good color image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal halide lamp used as a light source for liquid crystal projectors and the like.

[Summary of the invention]

The present invention provides a metal halide lamp used as a light source for liquid crystal projectors, etc., by coating the inner wall of the bulb with a fluorescent substance to increase the intensity of red light emission.
This makes it possible to improve red light emission, which metal halide lamps tend to lack, without changing the luminous intensity distribution of other colors.

[Conventional technology]

Recently, liquid crystal projectors have been actively developed.

FIG. 2 shows the basic configuration of a liquid crystal projector. This liquid crystal projector (1) has a white light fi (2), a color separation dichroic mirror (3) that constitutes a spectroscopic optical system, and
) [(3R), (3B)] and a reflecting mirror (
4I), transmissive liquid crystal light pulp that supports three primary colors (5
) [(5R), (5G).

(5B)], color separation dichroic mirror (6) [(6B), (6G)] that constitutes the synthetic optical system
It consists of a reflecting mirror (4□), etc. The light from the white light source (2) is separated by the red reflective dichroic mirror (3R), and the separated red light is reflected by the reflective mirror (41) and irradiated onto the surface of the red liquid crystal light pulp (5R). . The light that passes through the red reflective dichroic mirror (3R) passes through the blue reflective dichroic mirror (3B).
The blue light is separated, and the separated blue light is irradiated onto the surface of the blue liquid crystal light valve (5B). The light (green light) transmitted through the blue reflective dichroic mirror (3B) is irradiated onto the surface of the green liquid crystal light valve (5G). Each LCD light valve (5R), (5B), (5G)
Three independent images are formed by applying video data corresponding to each color of red (R), blue (B), and green (G), and a blue reflective dichroic ink mirror (6B) and a green reflective mirror are applied. Dichroic ink mirror (6G) and reflective mirror (
Each image is combined via a combining optical system consisting of 4□), and a color image is projected onto a screen.

As the white light source (2) of such a liquid crystal projector (1), for example, a metal halide lamp (see Writing Handbook, pages 145 to 148, published by Ohmsha, November 30, 1988) is used.

[Problems to be Solved by the Invention] Metal halide lamps used as white light sources for liquid crystal projectors have so far emitted light by sealing various light-emitting metal A halides in their arc tubes, but they tend to lack red light. It emits blue-white light. For this reason, there has been a problem in that it is difficult to obtain good color images with liquid crystal projectors using metal halide lamps.

In view of the above-mentioned points, the present invention provides a metal halide lamp that can compensate for red light emission intensity without changing the luminous intensity distribution of other colors.

[Means for Solving the Problems] A metal halide lamp (11) according to the present invention includes a fluorescent material (1) on the inner wall of a bulb (12) enclosing an arc tube (13).
9) is applied to increase the intensity of red light emission.

[Function] In the configuration of the present invention, the arc tube (12) is provided within the tube (12).
Since the inner wall of the metal halide lamp (11) containing 3) is coated with a fluorescent substance (19),
When the metal halide lamp (11) is operated, along with the normal light emission from the arc tube (13), the arc tube (11)
The fluorescent substance (19
) is excited and emits red light. This compensates for red light emission, which tends to be insufficient, without changing the luminous intensity distribution of other colors, and provides more preferable white light emission.

〔Example〕

An example of a metal halide lamp according to the present invention will be described below with reference to FIG. In this example, the present invention is applied to a metal halide lamp for a white light source of a liquid crystal projector.

In the same area, (11) shows the metal halide lamp of this example as a whole, (12) shows the tube (so-called outer tube), (1
3) is an arc tube enclosed in a bulb (12), and (14) is a reflecting mirror for unidirectionally irradiating light from the metal halide lamp (11). The arc tube (13) is made of quartz glass as usual, and has electrodes (15a) at both ends.

(15b) is sealed with, for example, a molybdenum foil, and the arc tube is filled with mercury, a metal halide, and a starting rare gas. An oxide heat-retaining film is provided on the quartz outer wall around the electrode. The light emitted from the arc tube (13) is a bluish-white light with insufficient red light as usual. In addition, (16) is an auxiliary pole for starting, (17) is a bimetal switch, (18) is a glow switch, and (20) is the direction of light.

However, in this example, a part of the inner wall of the tube (12),
For example, a fluorescent material (19) that emits red light, such as a red fluorescent material used in color cathode ray tubes, is applied to the area from the front surface of the bulb (12) to just below the arc tube (13).

According to the metal halide lamp (11) having such a configuration,
During operation, normal light is emitted from the arc tube (13), and the emitted light (i.e., near ultraviolet light) causes a fluorescent substance (red phosphor) (1
9) is excited and emits red light. As a result, the insufficient red light emission is compensated for without changing the luminous intensity distribution of other colors, and the overall light emission of the metal halide lamp (11) is
This results in more preferable white light emission. Therefore, this metal halide lamp (11) can be used as a liquid crystal projector (
If applied to the white light source (2) in item 11), the lack of red light emission can be resolved and a good color image can be obtained.

Note that although the above example is applied to a white light source of a liquid crystal projector, it can also be applied to other light sources.

〔Effect of the invention〕

According to the metal halide lamp of the present invention, the red light emission intensity, which is insufficient in conventional metal halide lamps, can be increased without changing the luminous intensity distribution of other colors. It is something to tighten.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a metal halide lamp according to the present invention, and FIG. 2 is a diagram showing the principle block diagram of a liquid crystal projector. (11) is a metal halide lamp, (12) is a tube (outer tube), (13) is an arc tube, (14) is a reflective mirror, (
15a). (15b) is an electrode, and (19) is a fluorescent material. Agent Hidemori Matsukuma

Claims (1)

[Claims] A metal halide lamp that is made by coating the inner wall of the bulb with a fluorescent substance to increase the intensity of red light.