JPH06243837A - Metal halide lamp device - Google Patents

Abstract

PURPOSE:To obtain a metal halide lamp device in which a color shade and an illuminance unevenness owing to a chip-off part of a luminous tube are reduced. CONSTITUTION:While a pair of electrodes are provided in a luminous tube 1, an additive mainly of a rare earth iodide is sealed in, a reflection cum heat insulation membrane 2 is provided on one side seal, so as to compose a short arc type metal halide lamp, and the metal halide lamp is fixed to the bottom of a reflecting mirror 4 through a base 5 and an adhesive 6. A chip-off part 3 formed on the luminous tube 1 is squashed to make the outer surface in a curved surface 3a, and when the curvature radius of the curved surface 3a is made RT, and the curvature radius of the outer surface of the luminous tube 1 is made RB, the RT is set in the scope 0.2 <=RT/RB<=3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal halide lamp device, and in particular, it is constructed by combining a so-called short arc type metal halide lamp, which is used only in an arc tube without an outer tube, and a reflecting mirror, The present invention relates to a metal halide lamp device used as a light source for a comparatively small image device that distributes light in a region limited to the above.

[0002]

2. Description of the Related Art In recent years, video equipment has been constructed by combining an active matrix type liquid crystal and an optical system.
2. Description of the Related Art Liquid crystal projectors, which enjoy images by projecting them on a large screen that exceeds 1 m diagonally, are becoming popular. And
As a backlight for such video equipment, a metal halide lamp device configured by combining a reflecting mirror with a short arc type metal halide lamp used only in an arc tube containing a rare earth halide without providing an outer tube is used. ing.

Conventionally, as shown in FIG. 4, a metal halide lamp device of this type has an arc length in which an additive mainly containing the rare earth halide is enclosed so that good color reproducibility and luminous efficiency can be obtained. A reflecting mirror 103 having a reflecting surface such as an elliptical surface, a parabolic surface, or a spherical surface on an arc tube 101 of 10 mm or less
Is integrally or removably combined with a base 104 provided at one end of the arc tube 101 via an adhesive 105, and when used as a backlight of a video device, a liquid crystal panel is arranged in front of it. It is installed so that the light emitted from the metal halide lamp device hits the liquid crystal surface. In FIG. 4, 102 is a chip-off portion formed on the outer surface of the arc tube 101 in the manufacturing process of the arc tube 101, and 106 is a lead wire.

[0004]

By the way, in the metal halide lamp device having such a structure, when the frosted surface is formed on the outer surface of the arc tube constituting the metal halide lamp, the light rays emitted from the inside of the arc tube are frosted. The light rays that are scattered by and are incident on the reflecting mirror at a designed angle at about 1/2, and other scattered rays are incident on the reflecting mirror in various directions, so the illuminance obtained on the screen However, since the light is a mixed light, the unevenness in illuminance and the unevenness in color are not so noticeable.

However, in order to increase the illuminance of the screen, the formation of the frosted surface on the outer surface of the arc tube is stopped, or the area of the frosted surface is reduced to increase the clear surface, and the arc tube has a clear surface or a part of the frosted surface. When a metal halide lamp device is configured by combining a light emitting tube having the above and a reflecting mirror, since the tip off portion of the exhaust pipe is formed in the light emitting tube, the shadow of the tip off portion is shown in FIG. In the isoilluminance distribution diagram shown in FIG. 3, there is a problem that color unevenness occurs on the screen as indicated by P.
5B is a diagram showing the illuminance distribution along the line AA ′ in FIG. 5A, and the dotted line is the diagram showing the illuminance distribution when the shadow of the chip-off portion does not occur. .

The mode in which the above-mentioned color unevenness occurs will be further described. The light emitted from the light emitting section is emitted from the chip-off section 102.
4, the tip-off portion 102 is formed to project at a relatively acute angle as shown in FIG. 4, and a part of the light beam emitted from the tip-off portion 102 is scattered by the lens effect and is reflected by the reflecting mirror 103. The light rays that are incident and that are incident on the substantially central portion of the reflecting mirror 103 are reflected again toward the tip-off portion 102. Therefore, a part of the light beam emitted through the tip-off portion 102 is blocked by the tip-off portion and does not reach the screen arranged on the front surface. The portion of the screen where the shadow of the tip-off portion is formed is supplemented by the light rays from the periphery of the reflecting mirror, and the light rays wrapping around from the periphery of the reflecting mirror are the arc tube
Since there are many red components around the arc of 1, the tip-off part 10
The red area component is added to the shadowed area of 2, which results in large color unevenness with a noticeably increased red component, and the illuminance of that area also decreases, which is a major problem.

The present invention has the above-mentioned problems in the conventional metal halide lamp device constituted by combining a metal halide lamp having a clear arc tube having no frosted surface or an arc tube partially having a frosted surface and a reflecting mirror. The present invention has been made to solve the above problems, and an object thereof is to provide a metal halide lamp device in which noticeable color unevenness and illuminance unevenness are reduced.

[0008]

In order to solve the above problems, the present invention provides a short arc type metal halide lamp having an arc length of 10 mm or less, which is used only in an arc tube without an outer tube, and a reflector. In a metal halide lamp device configured by combining, the tip-off portion formed in the arc tube is crushed to form a curved outer surface,
Let R _{B be the} radius of curvature of the outer surface of the arc tube where the tip-off portion is formed.
When the radius of curvature of the curved surface of the tip-off portion is R _T ,
It is intended to set in the range of _{0.2 ≦ R T / R B ≦} 3.

In the metal halide lamp device constructed as described above, the outer surface of the tip-off portion is crushed to form a curved surface having a radius of curvature close to that of the outer surface of the arc tube portion where the tip-off portion is formed. Since the light is emitted from the light emitting portion through the tip-off portion, it is not scattered and almost does not enter the central portion of the reflecting mirror. Therefore, the tip-off portion is crushed and the protruding portion is formed. In addition to the fact that the light is small, the number of light rays reflected by the central portion of the reflecting mirror and blocked by the chip-off portion is reduced, and the color unevenness and the illuminance unevenness due to the chip-off portion are reduced.

[0010]

EXAMPLES Next, examples will be described. FIG. 1 is a partial sectional view showing a first embodiment of a metal halide lamp device according to the present invention. In the figure, reference numeral 1 denotes an arc tube, which has a pair of electrodes and a DyI ₃ -Nd in a container made of translucent quartz glass having a maximum outer diameter of 11 mm and a maximum inner diameter of 8.8 mm and having a spheroidal shape.
About 0.8 m of I ₃ -CsI in a weight ratio of 8: 2: 5
g, Hg of 10 mg, Ar of 200 torr are enclosed, and a reflection and heat insulation film 2 made of a mixture of alumina-silica is applied to one side of the seal part. The arc length is 5.0 mm and the short arc type of 150 W rated lamp power is used. It constitutes a metal halide lamp. The arc-off tube 1 is provided with a tip-off portion 3 required for its manufacture. The tip-off portion 3 is crushed and its outer surface has a radius of curvature as shown in the enlarged view of FIG. Form a curved surface 3a of about 3.3 mm. The chip-off portion 3 is crushed by a simple process of crushing the chip-off portion with a heat-insulating material (carbon) that does not easily distort during chip-off.

The arc tube 1 constituting this metal halide lamp has an opening diameter of 110 mm and a focal length f =
In the parabolic reflector 4 having a size of 13 mm, the tube axis of the arc tube 1 and the central axis of the reflector 4 are aligned, and a base 5 provided at one end of the arc tube 1 is bonded with an adhesive 6. A metal halide lamp device is constructed by fixing the electrode lead wire at the other end of the arc tube 1 to a terminal 7 provided on the outer surface of the reflecting mirror 4 by fixing it to the bottom of the reflecting mirror 4 with a lead wire 8.

In the metal halide lamp device thus constructed, the outer surface of the tip-off portion 3 is crushed to form a curved surface having a radius of curvature substantially equal to 5.5 mm of the outer surface of the arc tube 1. Therefore, arc tube 1
As shown in FIG. 1, the light beam emitted from the light emitting portion of the light emitting portion through the tip-off portion 3 is similar to the light ray emitted from the outer surface portion of the arc tube 1 where the tip off portion is not provided,
The light is incident on the part of the reflecting mirror 4 away from the central part.
Further, since the tip-off portion 3 is crushed and formed small, the light rays reflected from the central portion of the reflecting mirror 4 and blocked by the tip-off portion 3 are also reduced. Color irregularities due to shadows are almost inconspicuous, and the illuminance is not reduced.

In the present invention, when the radius of curvature R _T of the curved surface formed on the outer surface of the tip-off portion is taken as the radius of curvature R _B of the outer surface of the arc tube on which the tip-off portion is formed,
It is intended to set in the range of _{2 ≦ R T / R B ≦} 3 , but will be described next set basis for this range. When you create what the outer surface of curvature radius R _B and the chip-off portion of the curved surface of curvature radius R _T of the arc tube and to various values, were experimented with occurrence of color unevenness and illuminance unevenness on the screen, R _T / R _B
When it is less than 0.2, color unevenness due to the shadow of the chip-off portion is likely to occur as in the conventional case, while R _T / R _B is 3
The result is that when the light source exceeds, the light becomes nearly flat, the emitted light is refracted and a lens effect occurs, and in particular, when the light source is arranged near the liquid crystal surface, unevenness is likely to occur on the screen. Therefore, in the present invention, 0.2 ≦ R _T / R _B
The range is set to ≦ 3.

In the first embodiment shown in FIGS. 1 and 2, the tip-off portion is shown as a simple flat mountain shape by crushing, but as shown in FIG. 3, it has a collar portion 3b. Even if it is formed in the shape of a collar, the same effect can be obtained.

[0015]

As described above on the basis of the embodiments,
According to the present invention, the chip-off portion is crushed and the outer surface thereof is made into a curved surface having a radius of curvature close to the radius of curvature of the outer surface of the arc tube. Therefore, color unevenness and illuminance unevenness due to the chip-off portion are reduced, and The decline can also be prevented.

[Brief description of drawings]

FIG. 1 is a first metal halide lamp device according to the present invention.
It is a figure which shows an Example with a partial cross section.

FIG. 2 is an enlarged view showing a chip-off portion of the embodiment shown in FIG.

FIG. 3 is an enlarged view showing a chip-off portion of a second embodiment.

FIG. 4 is a diagram showing a partial cross-section of a configuration example of a conventional metal halide lamp device.

FIG. 5 is a diagram showing an isolux distribution line on a screen by a conventional metal halide lamp device and a graph diagram showing the illuminance along the line AA ′.

[Explanation of symbols]

 1 Arc tube 2 Reflective and heat insulating film 3 Chip off part 4 Reflector 5 Base 6 Adhesive 7 Terminal 8 Lead wire

Claims (1)

[Claims] 1. A metal halide lamp device comprising a reflector and a short arc type metal halide lamp having an arc length of 10 mm or less, which is used only in an arc tube without an outer tube, and a chip-off formed in the arc tube. If the outer surface of the portion is crushed to form a curved surface, the radius of curvature of the outer surface of the arc tube in the portion where the tip-off portion is formed is R _B, and the radius of curvature of the curved surface of the tip-off portion is R _T , 0.2 ≦ R
A metal halide lamp device characterized by being set in a range of _T / R _B ≦ 3.