JP2004214102A - Short arc lamp with built-in reflecting mirror - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-weight short arc lamp with a built-in reflecting mirror. <P>SOLUTION: This short arc lamp with a built-in reflecting mirror is provided with a body 1 composed of insulating materials having a recessed form reflecting surface 1a to reflect the light generated by an arc formed between a positive electrode 5 and a negative electrode 4, a sealed space T formed in body, and sodium 12 sealed in this sealed space. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
【Technical field】
The present invention relates to a short arc lamp with a built-in reflector.
[0002]
[Prior art and its problems]
As a light source for an endoscope or a video projector, various types of short arc lamps with built-in reflectors that achieve both high security and compactness by using a built-in reflector and a sturdy ceramic body structure are known (for example, Patent Document 1, Patent Reference 2).
[0003]
[Patent Document 1]
Japanese Patent No. 3158873
[Patent Document 2]
Japanese Patent No. 3183145 [0005]
[Object of the invention]
An object of the present invention is to provide a short arc lamp with a built-in reflector.
[0006]
Summary of the Invention
A short arc lamp with a built-in reflecting mirror according to the present invention has a body made of an insulating material and having a concave reflecting surface for reflecting light generated by an arc formed between an anode and a cathode; and a body formed in the body. A closed space; and sodium sealed in the closed space.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of a short arc lamp with a built-in reflecting mirror to which the present invention is applied. This short arc lamp has a body 1 made of alumina ceramic which is an insulating material, and the body 1 has a reflection surface 1a on which a metal such as silver or aluminum is deposited. A discharge space S is formed on the inner surface side of the reflection surface 1a. In the discharge space S, a cathode 4 and an anode 5 are arranged to face each other along the optical axis of the reflection surface 1a. The rear end of the opposed cathode 4 and the front end of the anode 5 are located before and after the focal point of the reflection surface 1a.
[0008]
A ceramic ring 9, a copper ring (not shown), and a power supply ring 2 are arranged in this order at the tip (right end in FIG. 1) of the body 1 forming the tip opening of the reflection surface 1 a. 9, the copper ring and the power supply ring 2 are fixed to the tip of the body 1 by a ring-shaped first metal member 6. The power supply ring 2 and the first metal member 6 are each made of Kovar.
[0009]
A ring-shaped flange 10 is fitted into the inner surface of the power supply ring 2, and a circular window member 11 made of a transparent material such as sapphire glass is fixed to the inner peripheral surface of the flange 10.
[0010]
The discharge space S inside the reflection surface 1a is made airtight by the first metal member 6, the power supply ring 2, the flange 10 and the window member 11, and the discharge space S is filled with an inert gas such as xenon. I have.
[0011]
A conductive support member 3 extending in the radial direction of the power supply ring 2 is provided between the reflection surface 1 a and the window member 11. The conductive support member 3 is made of molybdenum, and its outer end is welded to the power supply ring 2 and its inner end is welded to the cathode 4. That is, the first metal member 6 is electrically connected to the cathode 4 via the power supply ring 2 and the conductive support member 3.
[0012]
An iron metal block (anode conduction block) 7 is fixed to the rear end of the body 1 via a ring-shaped second metal member 8. The anode 5 penetrates the axis of the metal block 7. Therefore, the second metal member 8 is electrically connected to the anode 5 via the metal block 7.
[0013]
The body 1 has a closed space T behind the reflection surface 1a. This closed space T is an annular space having a rotationally symmetric shape about the optical axis of the reflection surface 1a, and sodium 12 is sealed inside the space.
[0014]
That is, the body 1 has an umbrella-shaped wall portion 1b having a reflective surface 1a on the front surface, a rear end wall portion 1c that contacts the metal block 7, an outer peripheral edge of the umbrella-shaped wall portion 1b, and an outer peripheral edge of the rear end wall portion 1c. The outer cylindrical wall 1d to be connected, the inner cylindrical wall 1e connecting the inner peripheral edge of the umbrella-shaped wall 1b and the inner peripheral edge of the rear end wall 1c, and the sodium 12 sealed in the closed space T The umbrella-shaped wall 1b, the rear end wall 1c, the outer cylindrical wall 1d, and the inner cylindrical wall 1e are hermetically sealed.
[0015]
An arc is formed between the cathode 4 and the anode 5, and part of the heat generated by the arc is transmitted from the anti-slope surface 1a to the inside of the body 1. The main paths of heat transmitted to the inside of the body 1 are the anti-slope surface 1a, the body 1 (umbrella-shaped wall portion 1b), sodium 12, the body 1 (the rear end wall portion 1c and the outer cylindrical wall portion 1d), and the second metal member. 8 in that order.
[0016]
According to the short arc lamp having the above configuration, a closed space is formed in the body made of alumina ceramic, and sodium having a lower specific gravity than alumina ceramic is sealed in this closed space, so that the weight of the short arc lamp is reduced. You. The density of the alumina ceramic is about 3.6 g / cm ³ , and the density of sodium is 0.97 g / cm ³ .
[0017]
Furthermore, since the thermal conductivity of sodium is slightly inferior to the thermal conductivity of alumina ceramic, it is sufficiently high, so that the heat transmitted from the anti-slope surface 1a to the inside of the fuselage 1 passes through the above-mentioned path, that is, the anti-slope surface 1a, The portion 1b), the sodium 12, the body 1 (the rear end wall 1c and the outer cylindrical wall 1d) and the second metal member 8 are reliably transmitted and radiated heat in this order, so that a sufficient heat radiation effect can be obtained.
[0018]
In the above embodiment, the closed space T is formed in a rotationally symmetric shape about the optical axis of the reflection surface 1a. However, the closed space formed in the body 1 is divided into a plurality of sections, and sodium is applied to each section. You may make it the structure enclosed.
[0019]
【The invention's effect】
As described above, according to the present invention, since the sealed space is formed in the body and sodium is sealed in the closed space, the weight is reduced without substantially impairing the heat radiation effect of the heat transmitted from the anti-slope to the inside of the body. A short arc lamp with a built-in reflecting mirror can be provided.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of a short arc lamp with a built-in reflecting mirror to which the present invention is applied.
FIG. 2 is a front view showing a positional relationship among a power supply ring, a conductive support member, and a cathode of the short arc lamp with a built-in reflecting mirror shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Body 1a Reflection surface 2 Power supply ring 3 Conductive support member 4 Cathode 5 Anode 6 First metal member 7 Metal block (anode conduction block)
8 Second metal member 9 Ceramic ring 10 Flange 11 Window member (transparent member)
12 Sodium S Discharge space T Closed space

Claims (3)

A body made of an insulating material, having a concave reflecting surface for reflecting light generated by an arc formed between the anode and the cathode;
An enclosed space formed in the body;
Sodium enclosed in the enclosed space;
A short arc lamp with a built-in reflector. The short arc lamp with a built-in reflecting mirror according to claim 1, further comprising:
A transparent member fixed in front of the reflective surface, for sealing the discharge space inside the reflective surface and transmitting light reflected by the reflective surface;
An anode conduction block fixed to the rear end of the body and electrically connected to the anode, made of metal;
A short arc lamp with a built-in reflecting mirror, wherein the enclosed space in which sodium is sealed is formed between the reflecting surface and the anode conduction block. 2. A short arc lamp with a built-in reflector according to claim 1, wherein a cathode and an anode are arranged in the discharge space so as to face each other along the optical axis of the reflection surface, and the enclosed space in which sodium is sealed has the optical axis. A short arc lamp with a built-in reflector that has a rotationally symmetric shape.

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