JP2011198717A - Discharge lamp device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of preventing excessive cooling of a sealing section caused by cooling wind by effectively keeping a sealed tube at an opening side of a reflecting mirror base section of a discharge lamp, in a discharge lamp device including the discharge lamp and a reflecting mirror and arranged opposite to the reflecting mirror at a front surface opening side of the reflecting mirror and having an auxiliary mirror for reflecting a part of light emitted from the discharge lamp to the discharge lamp.SOLUTION: The auxiliary mirror is structured of a first auxiliary mirror and a second auxiliary mirror. The first auxiliary mirror reflects visible light from the discharge lamp to a discharge space of the discharge lamp, and the second auxiliary mirror reflects light transmitting the first auxiliary mirror to the sealing tube at the opening side of a base section of the reflecting mirror.

Description

  The present invention relates to a discharge lamp device used for a light source or the like of a projector, and more particularly to a discharge lamp device in which an auxiliary mirror is disposed on the light emission side of a discharge lamp.

  Conventionally, as a discharge lamp device used as a light source of a projector, a discharge lamp device including a discharge lamp and a reflecting mirror arranged so as to surround the discharge lamp is known, and an auxiliary mirror is provided on the discharge lamp. A technique is known in which light emitted from the discharge lamp and emitted in the direction of the front opening of the reflecting mirror is returned to the discharge lamp to increase the light utilization rate.

Japanese Patent Application Laid-Open No. 2007-220435 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2008-243640 (Patent Document 2) disclose conventional discharge lamp devices used in the above technical fields. The schematic structure is shown in FIG.
The discharge lamp device includes a discharge lamp 1 and a reflecting mirror 5.
The discharge lamp 1 includes an arc tube 2 and sealing tubes 3 (3a, 3b) formed at both ends thereof, and a pair of electrodes 4 and 4 are disposed in the discharge space S of the arc tube 2 to face each other. Has been. The reflecting mirror 5 disposed so as to surround the discharge lamp 1 has a reflecting surface that is a spheroidal surface, and is fixedly held by an adhesive 8 with one sealing tube 3 a inserted through the base opening 6. ing.

  An auxiliary mirror 20 is attached to the sealing tube 3 b on the front opening 7 side of the reflecting mirror 5. The auxiliary mirror 20 is disposed so as to face the reflecting mirror 5, and reflects the light emitted from the arc tube 2 of the discharge lamp 1 toward the front opening 7 side of the reflecting mirror 5 to emit light again. By returning to the space between the electrodes 4 and 4 in the discharge space S of the tube 2, the light utilization rate is improved.

By the way, in the structure in which the auxiliary mirror 20 is attached to the discharge lamp 1 as described above, the influence caused by the irradiation of light to the auxiliary mirror 20 and accumulation of heat, and the heat radiation from the discharge lamp 1 are caused by the auxiliary mirror 20. Therefore, the temperature of the discharge lamp 1 is likely to be higher than that of the structure in which the auxiliary mirror 20 is not provided due to the limitation.
Specifically, in the discharge lamp 1, the temperature of the sealing tube 3 b on the side where the auxiliary mirror 20 is attached becomes higher than the temperature of the sealing tube 3 a on the opposite side, and the temperature distribution of the discharge lamp 1 is biased. Occurs.
As a result, there is a problem that the temperature on the auxiliary mirror 20 side of the arc tube 2 becomes high and devitrification occurs.

  Therefore, attempts have been made to enhance the cooling of the lamp by forced air cooling to lower the temperature of the sealing tube on the side of the auxiliary mirror, but this time, the side opposite to the side on which the auxiliary mirror is attached, that is, the reflection mirror. There is a risk that the sealing tube on the base opening side will be supercooled and its temperature will become lower than necessary, and so-called blackening phenomenon will occur, in which the electrode material evaporated in the discharge space adheres to the inner wall of the arc tube. It was.

In the structure in which such an auxiliary mirror is attached, as a method for preventing overcooling of the sealing tube on the base opening side of the reflecting mirror on the side opposite to the side on which the auxiliary mirror is attached, It is disclosed that a heat retaining means is applied to the sealing tube on the base opening side of the reflecting mirror.
FIG. 5 shows Patent Document 1, which is on the side of the front opening 7 of the reflecting mirror 5 opposite to the sealing tube 3b to which the auxiliary mirror 20 is attached, that is, on the base opening 6 side of the reflecting mirror 5. The heat insulating film 21 is formed on 3a.
FIG. 6 shows Patent Document 2 in which a heat insulation coil 22 is wound around a sealing tube 3 a on the base opening 6 side of the reflecting mirror 5.

In these prior arts, since the heat retaining means is provided in the sealing portion on the base opening side of the reflecting mirror, it is possible to prevent overcooling of the sealing tube due to cooling of the lamp.
However, in the prior art, while the lamp is repeatedly turned on and off, in the case where the heat insulating film is formed, the heat insulating film may be peeled off due to a difference in expansion coefficient from the sealing tube, Further, in the case where the heat insulating coil is provided, there is a problem that the heat insulating coil repeatedly expands and contracts to tighten the sealing portion, and the sealing portion may be damaged and broken.

JP 2007-220435 A JP 2008-243640 A

  The problem to be solved by the present invention consists of a discharge lamp and a reflecting mirror, which is disposed opposite to the reflecting mirror on the front opening side of the reflecting mirror, and a part of the emitted light from the discharge lamp is supplied to the discharge lamp. In a discharge lamp device provided with an auxiliary mirror that reflects toward the surface, a structure is provided that effectively keeps the sealing tube on the reflection mirror base opening side of the discharge lamp, and prevents overcooling of the sealing portion by cooling air. To do.

In order to solve the above-mentioned problems, in the discharge lamp device according to the present invention, the auxiliary mirror is constituted by a first auxiliary mirror and a second auxiliary mirror, and the first auxiliary mirror is composed of the emitted light from the discharge lamp. Visible light is reflected toward the discharge space of the discharge lamp, and the second auxiliary mirror reflects light transmitted through the first auxiliary mirror toward the sealing tube on the base opening side of the reflecting mirror. It is characterized by.
Further, the second auxiliary mirror reflects ultraviolet rays.

  Further, the first auxiliary mirror and the second auxiliary mirror are respectively separate structures, and the second auxiliary mirror is disposed on the rear side opposite to the discharge lamp of the first auxiliary mirror. And

  Further, the first auxiliary mirror and the second auxiliary mirror are a glass integrated structure, and a reflection film is formed on a surface of the integrated structure on the discharge lamp side to form a first auxiliary mirror, The second auxiliary mirror is configured by forming a reflective film on the back surface of the monolithic structure opposite to the discharge lamp.

According to the discharge lamp device of the present invention, the first auxiliary mirror reflects visible light of the emitted light from the discharge lamp toward the arc tube to improve the light utilization rate. Reflecting light such as infrared rays and ultraviolet rays other than visible light transmitted through the first auxiliary mirror toward the sealing portion on the base opening side of the reflecting mirror of the discharge lamp, thereby raising the temperature of the sealing portion. Therefore, it is not necessary to have a structure that keeps heat by a heat insulating film or a heat insulating coil, the heat insulating film is not peeled off, or the sealing part is not damaged, and the effective heat holding of the sealing part on the base opening side of the reflecting mirror is achieved. realizable.
Thus, even if the temperature of the arc tube on the auxiliary mirror side is cooled by forced air cooling, the temperature of the arc tube on the opposite side can be prevented from excessively decreasing, and the temperature distribution of the arc tube on both sides of the discharge lamp is not biased. Therefore, devitrification of the arc tube and blackening phenomenon can be prevented.

Sectional drawing of the 1st Example of the discharge lamp apparatus of this invention. The partial expanded sectional view of FIG. Sectional drawing of a 2nd Example. The partial expanded sectional view of FIG. Sectional drawing of the conventional discharge lamp apparatus. Sectional drawing of the other conventional discharge lamp apparatus.

FIG. 1 is a cross-sectional view of the overall structure of the first embodiment, and FIG. 2 is an enlarged cross-sectional view of the auxiliary mirror portion.
In the figure, the discharge lamp 1 has the same structure as that of the above-described conventional example except for the heat retaining means. The discharge lamp 1 includes an arc tube 2 and sealing tubes 3 (3a, 3b) at both ends thereof. A pair of electrodes 4 and 4 are arranged to face each other.
One sealing tube 3 a of the discharge lamp 1 passes through the base opening 6 of the reflecting mirror 5 and is fixed by an adhesive 8.
An auxiliary mirror 10 is attached to the sealing tube 3 b on the front opening 7 side of the reflecting mirror 5 of the discharge lamp 1 so as to face the reflecting mirror 7.

The auxiliary mirror 10 includes a first auxiliary mirror 11 and a second auxiliary mirror 12 behind the first auxiliary mirror 11, that is, on the opposite side of the discharge lamp 1.
As shown in FIG. 2, the first auxiliary mirror 11 is fixed to the sealing tube 3 b of the discharge lamp 1 with an adhesive 13, and the second auxiliary mirror 12 is fixed to the first auxiliary mirror 11 with an adhesive 14. .

The first auxiliary mirror 11 is made of quartz glass, and a visible light reflecting film made of, for example, TiO ₂ and SiO ₂ is formed on the surface on the discharge lamp 1 side. The reflection surface is formed of a curved surface such that the reflected visible light returns to the discharge space S of the arc tube 2. In particular, it is preferable to return to the arc spot between the electrodes 4 and 4.
As a result, visible light is reflected from the light emitted from the arc tube 2 toward the front opening 7 of the reflecting mirror 5, and returned to the discharge space S of the arc tube 2, in particular, between the pair of electrodes 4, 4. Is.

The second auxiliary mirror 12 is a quartz glass coated with a metal coating (aluminum, gold, etc.), or a quartz glass having a plurality of low-refractive index layers and high-refractive index layers, and a buffer that reflects at least ultraviolet rays. A film is coated.
The low refractive index layer is SiO ₂ , and the high refractive index layer is ZrO ₂ , Nb ₂ O ₃ , Ta ₂ O ₅ or the like.
In addition, as a base material, a ceramic member other than quartz glass may be used, and the surface thereof may be polished and the above-mentioned coating may be applied.
The curved shape of the second auxiliary mirror 12 is such that the light reflected thereby irradiates the sealing portion 3a located on the base opening 6 side of the reflecting mirror 5 of the discharge lamp 1. Preferably, the electrode axis in the sealing portion 3a is irradiated. By doing so, the electrode shaft in the sealing tube 3a is heated and the temperature of the sealing tube 3a rises, so that the temperature deviation of the arc tube 2 can be made as small as possible.
The reflective film formed on the second auxiliary mirror may be any film that reflects light including ultraviolet light that is considered to contribute most to heating, and may reflect only ultraviolet light in some cases.

In the said Example, although a 1st auxiliary | assistant mirror and a 2nd auxiliary | assistant mirror consist of separate structures, these may be an integral structure and the structure is shown below.
FIG. 3 is a sectional view of the entire structure of the second embodiment, and FIG. 4 is an enlarged sectional view of the auxiliary mirror portion.
In the figure, the auxiliary mirror 10 provided in the sealing tube 3b on the front opening 7 side of the reflecting mirror 5 is made of quartz glass, the curved surface shape is different between the front surface and the back surface, and the surface on the arc tube 2 side is the first surface. One reflective surface, and the back surface on the opposite side is the second reflective surface.
Similar to the first embodiment, a visible light reflecting film is formed on the first reflecting surface to constitute the first auxiliary mirror 15. Further, similarly to the first embodiment, a buffer film for reflecting the light transmitted through the first auxiliary mirror 15 is formed on the second reflecting surface, and the second auxiliary mirror 16 is configured. To do.

The shape of the first reflecting surface that constitutes the first auxiliary mirror 15 is a curved surface such that the reflected visible light is returned to the discharge space S, and the second reflection that constitutes the second auxiliary mirror 16. The shape of the surface is such that the reflected light is applied to the sealing tube 3 a of the discharge lamp 1.
The auxiliary mirror 10 is attached to the sealing tube 3 b on the front opening 7 side of the reflecting mirror 5 of the discharge lamp 1 by an adhesive 17.
According to this embodiment, since the first auxiliary mirror and the second auxiliary mirror can be constituted by an integral structure, the number of parts can be reduced and the number of assembling steps can be reduced.
In any of the above embodiments, the discharge lamp 1 has a structure in which the discharge lamp 1 is directly fixed to the reflecting mirror 5 with the adhesive 8. However, the present invention is not limited to this, and a base having a different structure is used. A structure in which the lamp is attached to the lamp may be used.

As described above, the discharge lamp device according to the present invention reflects the visible light from the auxiliary mirror attached to the sealing tube on the front opening side of the reflecting mirror to which the discharge lamp is attached so as to face the reflecting mirror. And the second auxiliary mirror that reflects the light transmitted through the first auxiliary mirror to the sealing tube on the base opening side of the reflecting mirror. The sealing tube on the opening side can be effectively kept warm and is not overcooled by the cooling air.
In addition, since the heat insulation film or the heat insulation coil which has been conventionally provided is no longer necessary, the heat insulation film is not peeled off or the sealing tube is not damaged by turning on / off the lamp.

1 discharge lamp 2 arc tube 3 (3a, 3b) sealing tube 4 electrode S discharge space 5 reflecting mirror 6 base opening 7 front opening 10 auxiliary mirror 11 first auxiliary mirror 12 second auxiliary mirror 15 first auxiliary mirror 16 second Auxiliary mirror

Claims (4)

An arc tube having a discharge space in which a pair of electrodes are disposed, a discharge lamp having sealing tubes formed at both ends thereof, a reflecting mirror having the sealing tube of the discharge lamp attached to a base opening, and the reflection In a discharge lamp device comprising an auxiliary mirror disposed opposite to the reflecting mirror on the front opening side of the mirror and reflecting a part of the emitted light from the discharge lamp toward the discharge lamp,
The auxiliary mirror includes a first auxiliary mirror and a second auxiliary mirror,
The first auxiliary mirror reflects visible light out of the emitted light from the discharge lamp toward the discharge space of the discharge lamp;
The discharge lamp device according to claim 2, wherein the second auxiliary mirror reflects light transmitted through the first auxiliary mirror toward a sealing tube on a base opening side of the reflecting mirror.   The discharge lamp device according to claim 1, wherein the second auxiliary mirror reflects ultraviolet rays.   The first auxiliary mirror and the second auxiliary mirror are respectively separate structures, and the second auxiliary mirror is disposed on the rear side opposite to the discharge lamp of the first auxiliary mirror. The discharge lamp device according to claim 1. The first auxiliary mirror and the second auxiliary mirror are an integral structure made of glass, and a reflection film is formed on a surface of the integral structure on the discharge lamp side to form a first auxiliary mirror, and the integral structure 2. The discharge lamp device according to claim 1, wherein a second auxiliary mirror is formed by forming a reflective film on the back surface of the object opposite to the discharge lamp.

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