JP2001154270A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concave reflection mirror hardly broken even in the case of the burst of a discharge lamp provided in a light source device which is made small in size and light in weight, efficiently condenses the light radiated from a light source and irradiates a surface to be irradiated. SOLUTION: A short arc type discharge lamp whose mercury enclosing amount is >=0.15 mg/mm3, and two concave reflection mirrors having the same focal point in the vicinity of the center between the electrodes of the lamp are arranged in this light source device. Either concave reflection mirror constitutes the 1st concave reflection mirror arranged in the direction of a surface to be irradiated on the aperture side of the reflection mirror and the other constitutes a 2nd concave reflection mirror arranged on a surface to be irradiated on the non-aperture side of the reflection surface and consisting of one part of a nearly spherical surface. The diameter on the aperture side of the concave reflection mirror is <=65 mm, and the thickness of at least one part of the 2nd concave reflection mirror is larger than that of the 1st concave reflection mirror.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device used for a projection device such as a projector or a liquid crystal projector, or a lighting device using a fiber or the like.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory view showing the structure of a conventional optical device. The light source device 101 includes a concave reflecting mirror 103, a short arc discharge lamp 102, and a front glass 105.

The discharge vessel of the discharge lamp 102 is made of a light transmitting material, for example, quartz glass. The discharge lamp includes an arc tube portion 111 and a sealing portion 112 connected to both ends of the arc tube portion 111. In the arc tube portion 111, two electrodes 113 made of tungsten are arranged to face each other. . The sealing portion 112 has an electrode 113 and the outside of the arc tube while maintaining the airtightness between the inside of the arc tube and the outside during light emission.
And a molybdenum foil 114 for electrically connecting the electrode 113 to the electrode 113 by welding. The discharge lamp has about 0.15 mg / mm ³ of mercury sealed inside the arc tube in order to realize high luminance and high color rendering. Since the operating pressure of the discharge lamp is as high as 15 MPa or more, the shape of the arc tube portion 111 is designed to prevent stress concentration. For the purpose of preventing such problems, the shape is such that the inner surface area can be made large, for example, a rugby ball-shaped spindle shape or a spherical shape.

The concave reflecting mirror 103 has, for example, a spheroidal surface, and a hole 115 having a size corresponding to the maximum diameter of the arc tube portion 111 of the discharge lamp 102 is provided at the top for inserting a lamp. ing. The concave reflecting mirror 103
, A cylindrical leg 121 is integrally formed with the hole 115 as an inner diameter.

[0005] The concave reflecting mirror 103 is attached to the discharge lamp 102.
The discharge lamp 102 is assembled so that the lamp axis which is the arc direction of the concave mirror 103 and the optical axis of the concave reflecting mirror 103 coincide with each other.
The discharge lamp 102 is fixed to the hole 115 provided in the leg 121 of the concave reflecting mirror 103 using an alumina-based inorganic adhesive 104.

The concave reflecting mirror 103 is connected to the discharge lamp 1.
This is for efficiently irradiating the light to be irradiated on the irradiated surface 106 with the light from 02, and it is desirable that the light collection rate is high. Fig. 3, the light generated from the discharge lamp 102 is
Focal point P of the concave reflecting mirror 103 located near the center between the poles
From the optical path L indicated by an arrow in the figure toward the irradiated surface 106.
It is collected like.

In the concave reflecting mirror 103, light reflected on the opening side of the concave reflecting mirror is used relatively efficiently. However, the portion reflected near the hole 115, that is, the light reflected on the side where the lamp is close to the concave reflecting mirror, is blocked by the maximum diameter portion of the arc tube 111 of the lamp 102, and is almost unusable. Absent.

[0008] One reflecting mirror as shown in FIG. 3 cannot sufficiently utilize the light from the lamp. Therefore, as a method for efficiently using the light of the lamp on the side close to the reflecting mirror, Japanese Utility Model Publication No. 63-162320 discloses a light source device comprising two reflecting mirrors, one of which is one of the reflecting mirrors. What is part of a spherical surface is disclosed.

FIG. 4 shows a light source device comprising two reflecting mirrors. The light source device 201 includes a first concave reflecting mirror 203A, a second concave reflecting mirror 203B, and a short arc discharge lamp 202. The short arc discharge lamp 202 has the arc tube filled with about 0.15 mg / mm ³ of mercury similarly to the one shown in FIG.

The light reflected by the first concave reflecting mirror 203A efficiently reflects the light radiated from the lamp toward the opening side of the reflector, similarly to the reflector including one concave reflecting mirror. The light reflected by the second concave reflecting mirror 203B is returned to the vicinity of the center between the electrodes of the lamp, which is the focal point of the second concave reflecting mirror, which is composed of a part of a spherical surface. The light returned to the vicinity of the center between the electrodes is used again as energy contributing to light emission,
There is an advantage in that the light emitted in the direction of the concave reflecting mirror 203A is used to increase the light collection rate of the light used as the whole concave reflecting mirror.

However, as compared with a single concave reflecting mirror as shown in FIG. 3, the reflector having two concave reflecting mirrors shown in FIG. 4 has a problem that the lamp is more likely to be broken when the lamp bursts. .

[0012]

An object to be solved by the present invention is to provide a light source device for efficiently condensing light emitted from a light source and irradiating the light on a surface to be irradiated. It is an object of the present invention to provide a concave reflecting mirror that is not easily broken even when a discharge lamp bursts.

[0013]

A light source device according to the present invention comprises a short arc type discharge lamp in which a pair of electrodes are arranged inside an arc tube and a sealed amount of mercury is 0.15 mg / mm ³ or more. A concave reflecting mirror comprising two concave portions having the same focal point is arranged near the center between the electrodes of the lamp, and one of the concave portions is arranged in the direction of the irradiated surface which is the opening side of the reflecting mirror. A second concave reflecting mirror which forms a first concave reflecting mirror and the other concave portion of which is a part of a substantially spherical surface arranged in a direction opposite to a direction of an irradiated surface which is a non-opening side of the reflecting mirror; In the light source device, the diameter of the concave reflecting mirror on the opening side is 65 mm or less, and the pressure of at least part of the second concave reflecting mirror is lower than the pressure of the first concave reflecting mirror. It is also characterized by being thick.

In the light source device according to the present invention, in the above configuration, the thickness of the spherical portion forming the second concave mirror is at least 1.2 times the thickness of the approximate paraboloid forming the first concave mirror. Features.

The light source device according to the present invention is characterized in that, in the above configuration, a part of a leg of the light source device is formed integrally with a part of a spherical part which is the second concave reflecting mirror. I do.

The light source device according to the present invention is characterized in that, in the above structure, the second concave reflecting mirror is formed by sintering a material containing silica powder as a main component.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a light source device 201 comprising two reflecting mirrors as shown in FIG. 4, when a mode in which the reflecting mirror is broken is examined, a portion of the second concave reflecting mirror 203B is broken. The case turned out to be remarkable. After various investigations of this cause, the following three are considered to be the main causes. 1) The pressure when the lamp is turned on is very high. 2) There is a demand for a highly illuminated and miniaturized light source device according to market demands. In order to increase the light use efficiency of the miniaturized light source device, a reflecting mirror having two concave portions is used. The distance between the lamp and the reflecting mirror became very short by making the concave portion on the side close to the lamp spherical. 3) There is a difference in collision energy caused by a difference in the direction of collision of fragments when the lamp ruptures due to the mirror shape.

First, the lighting pressure of the lamp shown in 1) will be described with reference to FIG. The short arc discharge lamp 202 disposed in the light source device 201 contains 0.15 mg / mm ³ or more of mercury. The lamp 2
The lighting pressure of 02 becomes 15 MPa or more. This lighting pressure is about four times as high as that of a generally known metal vapor discharge lamp for a projector or the like. When the lamp 202 ruptures, this operating pressure is reflected by the reflecting mirror 203.
A, 203B, which is proportional to the kinetic energy. In other words, in the light source device 201 in which the lamp is arranged, when the lamp 202 ruptures, the reflecting mirrors 203A and 203B receive about four times the force due to the collision of the fragments.

Next, as shown in 2), the size of the optical device has been reduced in accordance with the demands from the market for downsizing, lightening, and increasing illuminance of liquid crystal projectors and fiber lighting devices. Due to the demands of this market, the light source device 201 itself is also required to be small and lightweight and have a high light collection rate, and the distance between the lamp 202 and the reflecting mirrors 203A and 203B is becoming very short. The energy at which the fragments scattered when the lamp 202 ruptures collides with the reflecting mirrors 203A and 203B increases as the distance to the collision surface decreases. That is, the shorter the distance from the lamp to the concave reflecting mirror, the higher the collision energy. Further, as the distance between the lamp 202 and the reflecting mirrors 203A and 203B becomes shorter, the temperature of the reflecting mirror surface rises, and the reflecting mirrors 203A and 203B become larger.
When the temperature difference between the front and back of 3B increases, thermal stress is generated, and the impact resistance decreases.

In order to realize only miniaturization, the length of the concave reflecting mirror is simply shortened, and
May be reduced. However, in this method, portions where light is reflected by the concave reflecting mirrors 203A and 203B,
The so-called light receiving solid angle becomes small, and the light collection rate of the light irradiated on the irradiation surface 206 is reduced. Therefore, even when the light source device 201 is miniaturized, in order to minimize the light-collecting efficiency, the reflecting mirror is formed of two concave portions, and a concave reflecting mirror having a spherical surface on the side adjacent to the lamp is used. is necessary. In the reflector having the two concave portions, the distance between the concave reflector and the lamp is very short as in the arrangement of 203B.

When the lamp 202 ruptures as shown in 3), the scattered fragments are formed by two concave portions.
Considering the case of colliding with 3A, 203B, the impact depends on the direction of collision. When the shape of the reflector is a spheroid or a paraboloid generally used, the rupture side of the lamp collides obliquely with the reflector surface. On the other hand, when the concave reflecting mirror has a spherical surface, the rupture side of the lamp collides perpendicularly to the reflecting mirror surface. In the case of a light source device comprising two concave reflecting mirrors, the first concave reflecting mirror is incident at a certain angle with respect to the surface, so that the direction perpendicular to the surface of the first concave reflecting mirror is used. The impact energy due to the debris received by the shard is reduced. On the other hand, in the second concave reflecting mirror, debris collides in a direction substantially perpendicular to the surface. That is, all the kinetic energy of the fragments scattered by the rupture of the lamp is directly received in front of the reflecting surface. The impact energy received by the spherical surface is higher than that by the parabolic surface.

FIG. 5 shows a light source device 3 having two concave reflecting mirrors.
1 shows the schematic diagram. The first concave reflecting mirror 303A formed on the opening side of the light source device 301 is substantially a paraboloid, and the second concave reflecting mirror 30A is located on the side close to the lamp 302.
3B is formed substantially as a spherical surface. A second concave reflecting mirror 303B having a spherical surface is formed at an angle formed by rotating the axis about the focal point P of the reflecting mirror about the arc direction of the discharge lamp 1 in the range of 40 ° to 80 °. ing.

In the light source device 301, when the discharge lamp 302 ruptures, it is examined which part of the concave reflectors 303A and 303B collides with fragments of the discharge lamp 302, and the arc direction of the discharge lamp 302 is determined. , The angle formed by rotating the axis about the focal point P of the reflecting mirror was in the range of 60 ° to 120 °. The minimum incident angle on the first concave reflecting mirror 303A in the scattering direction of the fragments is about 40 °, and in the thickness direction defined by the normal distance to the reflecting surface of the first concave reflecting mirror 303A. The working force is about 75% of the kinetic energy of the fragments.
The impact strength of the reflecting mirror is approximately proportional to the square of the thickness. That is, the second concave reflecting mirror needs to be about 1.15 times as thick as the first concave reflecting mirror.

Specific examples will be described below. FIG. 1 is a cross-sectional view illustrating a configuration of a light source device according to a first embodiment of the present invention. In this light source device 1, a short arc type discharge lamp 2 is incorporated in a concave reflecting mirror 3 such that a lamp axis in an arc direction and an optical axis of the concave reflecting mirror 3 coincide with each other. The front glass 5 is fixed to the hole 15 provided in the portion 21 using the alumina-based inorganic adhesive 4, and the front glass 5 is attached to the opening 7 side of the concave reflecting mirror 3.

The discharge lamp 2 is a short arc type AC lighting ultra-high pressure mercury lamp with a rated input of 150 W. The discharge vessel is composed of a transparent quartz glass arc tube portion 11 and sealed tubes connected to both ends of the arc tube portion 11. And a stop portion 12. The arc tube 11 has a maximum diameter of 11 mm and a thickness of 2.5.
mm, a spindle having an inner volume of about 150 mm ^3, the inside, tungsten two electrodes 13 as the distance between the electrodes is 1.5mm are facing each other, mercury 0.1
5 mg / mm ³ or more is enclosed. In addition, the sealing portion 12 includes
A molybdenum foil 14 for electrically connecting the outside of the arc tube and the electrode 13 while maintaining the airtightness between the inside of the arc tube and the outside of the arc tube
Is built in and is joined to the electrode 13 by welding.

The concave reflecting mirror 3 is made of sintered quartz glass containing silica powder as a main component and has TiO ₂ and SiO ₂ on its inner surface.
_A visible light reflecting film made of a dielectric multilayer film composed mainly of ₂ is formed, and two concave reflecting mirrors 22 and 23 and a leg 21 having a focal point near the center between the electrodes in the discharge lamp 2 are formed.
Are integrally formed.

The part forming the second concave reflecting mirror 23 is as follows.
The angle formed by rotating the lamp axis, which is the arc direction of the discharge lamp 2, around the focal point P of the second concave reflecting mirror 23 is formed in the range of 40 ° to 80 °. The second concave reflecting mirror 23 is a spherical mirror having a radius of 9 mm around the focal point, and has a diameter on the opening side of 17 mm. Further, a hole 15 having a diameter of 11 mm is provided at the top of the second concave reflecting mirror 23 for inserting a lamp. The wall pressure of the second concave mirror 23 is 4 mm in the normal direction with respect to the focal point.

The range in which the first concave reflecting mirror 22 is formed is as follows.
The angle formed by rotating the lamp axis about the focal point P of the first concave reflecting mirror 22 is in the range of 80 ° to 150 °. The first concave reflecting mirror 22 is an elliptical mirror having a lamp axis as a base axis, and its opening diameter is about φ60 mm. The wall pressure of the first concave mirror 22 is 3.3 mm.

The second concave reflecting mirror 23 and the first concave reflecting mirror 22 are formed continuously, and the leg 21 is integrally formed on the back surface of the second concave reflecting mirror 23. I have. The thickness of the leg portion 21 is about 3.5 mm in the radial direction about the lamp axis, and the wall pressure in the normal direction of the second concave mirror is 4 mm.

In the light source device 1 of the embodiment, the light emitted from the discharge lamp 2 is arranged such that the focal point P comes near the center of the gap between the electrodes 13 and is provided so as to cover the lamp. Is returned to the light source unit by the concave reflecting mirror 23, and the first concave mirror 22 disposed so as to have the same focal point P as the second concave reflecting mirror toward the irradiated surface 6;
The light is efficiently collected as indicated by an optical path L indicated by an arrow in the figure.

When the discharge lamp 2 ruptures and its fragments collide, the concave reflecting mirrors 22 and 23 having the above-mentioned structure are applied to, for example, 70 ° 110 ° with respect to the focal point at the lamp axis.
If the fragments are scattered in the direction of the rotated virtual axis, they impinge at an angle of about 50 ° with respect to the normal direction when colliding with the first concave reflecting mirror 22, so that the first concave surface The impact force in the vertical direction of the reflecting mirror 22 is reduced to about 65% as compared with the case where the light is incident in the normal direction. On the other hand, when the debris collides with the second concave reflecting mirror 23, an impact is applied to the reflecting surface of the second concave reflecting mirror 23 in a direction substantially perpendicular thereto. However, as compared with the thickness of the first reflecting mirror 22, the thickness of the second concave reflecting mirror 23 having a part of the spherical surface is 1.2 times or more, and the shock resistance is several tens%. Since the above has also improved, the second
Is hardly destroyed.

FIG. 2 shows a second example of the light source device according to the present invention.
It is explanatory drawing which shows Example of this. The leg portion 21 is disposed so as to overlap a part of the back surface of the second concave reflecting mirror 23,
The thickness of the second concave reflecting mirror 23 is increased by a length substantially corresponding to the length of the leg portion. This is an example in which the impact resistance of the second concave reflecting mirror is improved as compared with the case of the first embodiment shown in FIG.

As described above, according to the light source device 1 of the present invention, a lamp having an extremely high internal pressure at the time of lighting is arranged, and light is efficiently condensed even if the size is reduced. A reflecting mirror comprising two concave portions having the same focal point near the center between the electrodes of the lamp, and the reflecting mirror on the side close to the lamp is formed into a spherical surface, whereby a second mirror comprising the spherical portion is formed. Even when the distance between the reflecting mirror 23 and the lamp is very short, the light source device 1 can be formed by increasing the wall pressure of the second concave reflecting mirror 23 and colliding with fragments scattered when the lamp bursts. Is prevented from being destroyed. Further, the leg 2 is provided on a part of the back surface of the second concave reflecting mirror 23.
By integrally forming No. 1, it was possible to enhance the impact resistance at the time of lamp rupture. Further, for the concave reflector which enables the light of the lamp in which the shape of the second concave reflector is substantially a part of a spherical surface to be efficiently collected, the thickness of the concave reflector is increased. Also, by integrally forming the legs on a part of the back surface of the concave reflecting mirror, the impact resistance at the time of lamp rupture is enhanced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a second embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a conventional optical device.

FIG. 4 is an explanatory view showing a configuration having two concave reflecting mirrors in a conventional optical device.

FIG. 5 is an explanatory view showing a configuration range of two concave reflecting mirrors of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source device in this invention 2 Discharge lamp 3 Concave reflector 4 Alumina-based inorganic adhesive 5 Front glass 6 Irradiation surface 7 Opening of concave reflector P Focus of concave reflector L Optical path of light generated from lamp 11 Discharge lamp 12 Arc tube part of discharge lamp 13 Electrode of discharge lamp 13 Electrode of discharge lamp 14 Molybdenum foil arranged in the seal part of discharge lamp 15 Hole 21 Leg 22 First concave reflecting mirror 23 Second concave reflecting mirror 101 Conventional light source device 102 Discharge lamp 103 Concave reflector 104 Alumina-based inorganic adhesive 105 Front glass 106 Illuminated surface 111 Arc tube part of discharge lamp 112 Seal part of discharge lamp 113 Electrode of discharge lamp 114 Seal part of discharge lamp Molybdenum foil 121 legs of concave reflecting mirror 201 conventional light source device 202 discharge lamp 203A first Surface reflecting mirror 203B Second concave reflecting mirror 301 Light source device of the present application 302 Discharge lamp 303A First concave reflecting mirror 303B Second concave reflecting mirror a Configuration range of second concave reflecting mirror b Rupture fragments of discharge lamp scatter Range

Claims (4)

[Claims] 1. A short arc type discharge lamp in which a pair of electrodes are arranged inside an arc tube and the amount of mercury is 0.15 mg / mm ³ or more, and the same near the center between the electrodes of the lamp. A concave reflecting mirror consisting of two concave portions having a focal point is arranged, and one of the concave portions constitutes the first concave reflecting mirror arranged in the direction of the irradiated surface which is the opening side of the reflecting mirror, and the other. A light source device in which one of the concave portions constitutes a second concave reflecting mirror which is part of a substantially spherical surface arranged in a direction opposite to a direction of an irradiated surface which is a non-opening side of the reflecting mirror. A light source device, wherein the diameter of the opening of the reflecting mirror is 65 mm or less, and the pressure of at least a part of the second concave reflecting mirror is thicker than the thickness of the first concave reflecting mirror. 2. The method according to claim 1, wherein the thickness of the spherical portion forming the second concave mirror is at least 1.2 times or more the thickness of the approximate paraboloid forming the first concave mirror. Light source device. 3. The light source device according to claim 1, wherein a part of a leg of the light source device is formed integrally with a part of a spherical portion serving as the second concave reflecting mirror. . 4. The light source device according to claim 1, wherein said second concave reflecting mirror is formed by sintering a material containing silica powder as a main component.