JP6440102B2 - Laser drive lamp - Google Patents

Description

  The present invention relates to a laser-driven lamp, and more particularly to a laser-driven lamp in which a lamp body and a reflecting mirror are integrated.

  In recent years, an ultraviolet light source having a higher output has been demanded in the manufacturing process of objects to be processed such as semiconductors, liquid crystal substrates and color filters. As such an ultraviolet light source, instead of a conventional high-pressure discharge lamp, a technique has been proposed in which energy is introduced into a discharge space by a laser to excite a luminescent gas to obtain ultraviolet radiation. Japanese Patent Application Laid-Open No. 2010-170112 (Patent Document 1) is an example.

In the prior art disclosed in Patent Document 1, as shown in FIG. 5, the plasma generation container 20 includes a light emitting portion 21 and a sealing portion 22 made of quartz glass. Mercury and xenon are enclosed.
In this example, the plasma generation container 20 is an electrodeless plasma generation container. The plasma generating container 20 is disposed at one focal point F1 of the elliptical reflecting mirror 30. On the other hand, a laser light generator 40 is provided outside the elliptical reflecting mirror 30, and laser light composed of, for example, a pulse laser or a CW (Continuous Wave) laser is introduced from the laser light generator 40 into the plasma generation container 20. The
The laser light emitted from the laser light generator 40 is introduced through the window 51 of the plane mirror 50, and is condensed by the condensing lens 60 disposed between the window 51 and the plasma generation container 20 to be plasma. The generating container 20 is irradiated. By condensing the laser light, the energy density can be increased at the condensing point F1, the luminescent material can be excited, and radiant light (ultraviolet light) can be generated. The emitted light is reflected by the ellipsoidal reflecting mirror 30 and reflected to the irradiated object side.

In such a conventional laser-driven lamp, quartz glass is used as the material of the plasma container. However, the plasma container is susceptible to ultraviolet distortion due to irradiation with high-power UV light and VUV light from the plasma. There's a problem.
If such UV distortion accumulates, there will be a risk that the glass surface will eventually crack and that the lamp will break.
To avoid this, ultraviolet crystal distortion can be reduced by using a crystal material such as crystal or sapphire as the plasma generation container. However, it is extremely difficult to manufacture a cylindrical or spherical container with a crystal material. That's not realistic.

JP 2011-170112 A

  In view of the above-mentioned problems of the prior art, the present invention is a laser-driven lamp in which a luminescent gas is sealed and laser light is focused and incident to generate plasma, and irradiation of high-power UV light and VUV light from plasma Even if it receives, a structure which can generate a high-density plasma can be obtained without causing ultraviolet distortion in the plasma container, and taking a solid angle of the incident laser light.

In order to solve the above-described problems, a laser-driven lamp according to the present invention includes a body portion having a concave reflecting surface, a light incident window and a light exit window attached to the body portion via a window mounting cylinder. The body portion, the light exit window, and the light entrance window form a sealed space, and the luminescent gas is sealed in the sealed space, and an exhaust pipe communicating with the sealed space includes the body. It is attached to the part or the said window attachment cylinder.
Further, the window mounting cylinder is made of metal, and the exhaust pipe is mounted on the window mounting cylinder.
The body part is made of ceramics, and the exhaust pipe is attached to the body part.

According to the present invention, the laser-driven lamp is composed of the body portion, the light exit window and the light entrance window on the front and rear surfaces thereof, and the sealed space is formed by these, so that a material other than quartz glass as the constituent material of the body portion, For example, ceramics, metals, etc. can be used, and since a light-transmitting crystal material can be used for the light entrance window and the light exit window, even if it is irradiated with high-power UV light and VUV light from plasma, A laser-driven lamp with higher output and longer life can be realized without distortion.
Further, the exhaust pipe communicating with the sealed space is attached to the body portion or the window mounting cylinder for attaching the light incident window and the light exit window to the body portion, so that the light enters the light entrance window. Therefore, the laser beam is not shielded by the exhaust pipe, the solid angle can be increased, and the energy density input to the plasma can be increased.

Sectional drawing of the Example of this invention. Sectional drawing of the other Example of this invention. Sectional drawing of other Example of this invention. Sectional drawing of other Example of this invention. Explanatory drawing of a prior art.

FIG. 1 shows an embodiment of the present invention. A laser-driven lamp 1 includes a columnar body portion 2, a light emission window 3 provided on the front and rear surfaces thereof, and a light incident window 4. The body portion 2 is made of a ceramic material such as polycrystalline alumina (Al ₂ O ₃ ).
A concave reflecting surface 5 is formed on the front side of the body portion 2, and a laser beam passage hole 6 penetrating the concave reflecting surface 5 in the optical axis direction is formed at the center thereof. The laser beam passage hole 6 is chamfered at the rear end side, that is, the incident side, to form a tapered portion 6a. The taper 6a is configured to prevent the condensed laser light from being kicked and blocked on the incident side of the laser light passage hole 6 when introduced through the light incident window 4 and guided to the laser light passage hole 6. It is to prevent.
The concave reflecting surface 5 is configured by a parabolic shape or an elliptical shape, and is described as a parabolic reflecting surface in this embodiment. The concave reflecting surface 5 is formed of a metal vapor deposition film in which aluminum or the like is vapor deposited on the concave surface portion of the body portion 2 or a dielectric multilayer film.

The light exit window 3 provided in front of the concave reflecting surface 5 is ultraviolet light transmissive, and the rear light incident window 4 is laser light transmissive, and both are made of a crystal material such as quartz or sapphire. And each outer peripheral surface is coat | covered with the metal which consists of a mixture of molybdenum and manganese, for example, and is metallized.
Further, the front and rear end portions of the outer peripheral surface of the body portion 2 are also subjected to metallization processing in the same manner as the light exit window 3 and the light entrance window 4.
The light exit window 3 and the light entrance window 4 whose outer peripheral surfaces are metallized are joined to metal elastic ring members 10 and 12 by brazing such as silver brazing, respectively, while the outer peripheral surface of the body portion 2 Metallized window mounting cylinders 11 and 13 are joined to the metallized front and rear ends by brazing. The ring members 10 and 12 and the window mounting cylinders 11 and 13 are welded together by TIG welding, laser welding, or the like.

  The body portion 2 assembled in this way, the light exit window 3 and the light entrance window 4 constitute a plasma container, in which a sealed space S is formed, and a luminescent gas is formed in the sealed space S. A rare gas such as xenon gas, krypton gas, or argon gas, or mercury gas is sealed in accordance with a desired emission wavelength.

  An exhaust pipe 15 is brazed to the window mounting cylinder 13 of the light incident window 4 and communicates with the sealed space S. After the sealed space S is evacuated through the exhaust pipe 15, the luminescent gas is sealed, and then the end 15a of the exhaust pipe 15 is pressure-cut and sealed.

  In the laser drive lamp 1 of the present invention, a laser beam L from a laser beam generator (not shown) is collected by a condenser lens 14 and introduced through a light incident window 4. At this time, the condensing point of the laser beam L is at the focal position F of the concave reflecting surface 5. The light emission gas is excited by the plasma generated at the focal position F by the laser light L to emit ultraviolet light (excitation light) EL, and this ultraviolet light EL is reflected by the concave reflecting surface 5 and passes through the light exit window 3. It is emitted forward.

  FIG. 2 shows another embodiment, in which the exhaust pipe 15 is attached to the window mounting cylinder 11 of the light exit window 3. Other configurations are the same as those of the embodiment of FIG.

  FIG. 3 shows still another embodiment. In this example, the exhaust pipe 15 is attached to the body portion 2, and the exhaust pipe 15 is communicated with the body portion 2 in the sealed space S. A communication hole 16 is formed. When the exhaust pipe 15 is attached, a predetermined attachment region of the body portion 2 can be metallized, and the exhaust pipe 15 can be attached thereto by brazing. Other configurations are the same as those of the embodiment of FIG.

  As described above, since the exhaust pipe 15 for evacuating the sealed space S and enclosing the luminescent gas is attached to the body portion 2 or the window mounting cylinders 11 and 13, the laser incident from the incident window 4. The light L is not shielded by the exhaust pipe 15, and the incident solid angle can be maximized without being restricted by the exhaust pipe 15. Therefore, the energy density input to the plasma can be increased.

In the above embodiment, the exit window 3 and the entrance window 4 are both attached to the window mounting cylinders 11 and 13 via the elastic ring members 10 and 12, but the window mounting frame is shown. It may be attached via the body.
An example is shown in FIG. 4, and the entrance window 4 is joined to a metal window mounting frame 17 by brazing, and this metal window mounting frame 17 is connected to the window mounting cylinder 13. It is welded by TIG welding or laser welding.
Such a window can be attached to the same structure on the exit window 3 side.
However, in any of these cases, on the incident window 4 side, the window mounting frame 17 has a size within a range that can secure the maximum incident solid angle of the incident laser light L, and on the emission window 3 side. Of course, it is necessary to have a size that can ensure an effective emission range of the emitted ultraviolet light (excitation light) EL.

As described above, the laser-driven light source of the present invention comprises a trunk part having a concave reflecting surface, and a light incident window and a light emission window attached to the trunk part via a window mounting cylinder. A sealed space is formed by the body portion, the light exit window, and the light entrance window, and the light emission gas is sealed in the sealed space, so that the body is irradiated with high-power UV light and VUV light from the plasma. However, there is an effect that ultraviolet distortion does not occur in the plasma container.
In addition, by evacuating the sealed space and providing an exhaust pipe that encloses the luminescent gas at a position different from the incident position of the laser beam, the solid angle of incidence of the laser beam can be maximized and high density The plasma can be generated.

DESCRIPTION OF SYMBOLS 1 Laser drive lamp 2 Body part 3 Light emission window 4 Light incident window 5 Concave-reflection surface 6 Laser light passage hole 6a Tapered part 10 Ring member 11 Window attachment cylinder 12 Ring member 13 Window attachment cylinder 14 Condensing lens 15 Exhaust pipe 15a Pressure contact portion 16 Communication hole 17 Window mounting frame F Focus S Sealed space L Laser light EL Ultraviolet light (excitation light)

Claims (1)

A laser-driven lamp in which a light-emitting gas is sealed and laser light is focused and incident to generate plasma;
The laser drive lamp is
Consists of a body part formed with a concave reflection surface, a light incident window and a light emission window made of a translucent crystal material attached to the body part via a metal window mounting cylinder.
A laser beam passage hole is formed in the optical axis direction at the center of the concave reflecting surface of the body part,
A sealed space is formed by the body portion, the light incident window, and the light exit window, and the luminescent gas is sealed in the sealed space,
The window mounting cylinder is attached with an exhaust pipe having an end sealed to communicate with the sealed space, evacuate the sealed space, and enclose the luminescent gas.
A laser-driven lamp characterized by that.

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