JP2009117881A - Aperture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce reflection and scatter of laser light, and prevent the peripheral members from being heated up. <P>SOLUTION: An aperture 23, which restricts the beam diameter of a laser light R emitted from an axial direction end of a laser lod 2 when the laser light R is passing through its aperture 24, is made of a material that allow the laser light R to pass through, and has an edge portion 25 for narrowing the beam diameter by restricting excessive laser light Ra, and the both surface of the edge portion 25 form a wedge shape toward the aperture 24, and the wedge shape is formed in such a way that laser light entered from one of incident surfaces 26 is reflected on the opposite side incident surface 26 toward the inside thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an aperture for focusing laser light.

  As shown in FIG. 5, in a general solid-state laser oscillator, a laser rod 2 (for example, a solid-state laser medium such as an Nd: YAG laser rod) and an excitation lamp 3 (an excitation light source such as a krypton lamp) are provided in a housing called a cavity 1. The cavity 1 is positioned and installed on the optical surface plate, and the transmission mirror 4 (partial reflection mirror) and the reflection mirror 5 (total reflection mirror) that form an optical resonator are arranged at the front and rear positions of the cavity 1. Then, light is emitted with the laser rod 2 in an excited state by lighting the excitation lamp 3 in the cavity 1, and the light is reciprocated between the transmission mirror 4 and the reflection mirror 5 to enter and exit the laser rod 2. By repeating the optical resonance, the optical energy is amplified and the laser beam R can be oscillated through the transmission mirror 4.

  In this type of laser oscillator, an opening 6 is formed in the central portion between the cavity 1 and each of the transmission mirror 4 and the reflection mirror 5 at the front and rear positions thereof, as shown in FIGS. The thin plate-like aperture 7 made of metal is disposed, and the edge 8 is passed through the opening 6 having a wedge shape in the thickness direction, thereby limiting the laser beam Ra of the extra outer portion having the required beam divergence angle. The diameter is narrowed down so that good beam quality with high directivity can be maintained.

  However, there is a problem in that the excess laser light Ra limited by the metal aperture 7 is reflected and scattered, hits a member located around the aperture 7 and heats the surrounding member.

  The present invention has been made in view of the above circumstances, and aims to reduce reflection and scattering of laser light and prevent heating of surrounding members.

The invention according to claim 1 is an aperture for narrowing the beam diameter of the laser beam through the opening with respect to the laser beam emitted from the axial end of the laser rod, and is made of a material that transmits the laser beam. In addition, both sides of the edge that restricts excess laser light and narrows the beam diameter form a wedge shape toward the opening, and the laser light incident on the inside from one incident surface is reflected toward the predetermined inside by the incident surface on the opposite side. The aperture is characterized by being formed as described above.

In the first aspect of the present invention, preferably, an absorbing material that absorbs heat of the limited laser beam may be provided, or a cooler that prevents heating of the absorbing material may be provided.

According to the first aspect of the present invention, when the laser beam is passed through the aperture of the aperture and the beam diameter is narrowed, the limited excess laser beam is incident on the inside of the aperture from one wedge-shaped incident surface, It travels through a predetermined interior of the material that is reflected and transmitted by the opposite entrance surface of the wedge shape, and is guided to the outside from a predetermined position of the aperture.

  In this way, the laser beam limited by the edge travels through a predetermined inside of the aperture instead of being reflected and scattered, and is guided to the outside from a predetermined position of the aperture. Therefore, the limited laser beam is reflected and scattered by the aperture. It is possible to prevent the surrounding members from being heated without hitting the members located around the periphery. Further, since the edge of the aperture is formed in a simple wedge shape, it can be easily molded, and the manufacturing cost can be reduced.

As in the second aspect of the invention, when the absorbing material that absorbs the heat of the limited laser beam is provided, the laser beam guided to the inside of the aperture is absorbed by the absorbing material, so that the laser beam is limited. Edge heating can be prevented.

If the cooler for preventing the absorbent material from being heated is provided as in the third aspect of the invention, the absorbent material can also be prevented from being heated, so that the edge and the absorbent material can be reliably prevented from being heated.

According to the first aspect of the present invention, the laser beam limited by the edge travels through the predetermined inside of the aperture instead of being reflected and scattered, and is guided to the outside from the predetermined position of the aperture. Does not hit a member located around the aperture due to reflection or scattering, and heating of the surrounding member can be prevented. Further, since the edge of the aperture has a simple wedge shape, it can be easily molded, and the manufacturing cost can be reduced.

As in the second aspect of the invention, when the absorbing material that absorbs the heat of the limited laser beam is provided, the laser beam guided to the inside of the aperture is absorbed by the absorbing material, so that the laser beam is limited. Edge heating can be prevented.

If the cooler for preventing the absorbent material from being heated is provided as in the third aspect of the invention, the absorbent material can also be prevented from being heated, so that the edge and the absorbent material can be reliably prevented from being heated.

It is a longitudinal cross-sectional view which shows the 1st reference example of an aperture . It is the schematic which shows the state provided with the absorber and the cooler in the aperture of the 1st reference example . It is a longitudinal cross-sectional view which shows the 2nd reference example of an aperture . It is a longitudinal cross-sectional view which shows the 1st example of embodiment of the aperture of this invention. It is a schematic plan view which shows an example of a general solid-state laser oscillator. It is a longitudinal cross-sectional view which shows the example of the conventional aperture. It is a top view which shows the example of the conventional aperture.

Hereinafter, reference examples and embodiments of the present invention will be described with reference to the drawings.

A first reference example of the aperture will be described with reference to FIGS. 1 and 2. The aperture 9 of the first reference example is formed by perforating a thin plate with an opening 10 in the central portion.

  The aperture 9 is made of a transparent material such as optical glass, and preferably has a high light transmittance and high thermal conductivity such as sapphire and YAG.

  The edge portion 11 of the opening 10 of the aperture 9 has both surfaces formed on the incident surface 12 perpendicular to the laser beam R in the thickness direction of the aperture 9 and is provided with a non-reflective coating. A V-shaped cutout 14 is formed so as to have a reflection surface 13 that totally reflects light.

  On the other hand, the aperture 9 is provided with an absorbing material 15 such as metal painted in black so as to absorb heat, and the absorbing material 15 is provided with a cooler 16.

Hereinafter, the operation of the first reference example will be described.

  When the beam diameter is narrowed by passing the laser beam R through the opening 10 of the aperture 9, the limited excess laser beam Ra is incident on the inside of the aperture 9 from the vertical incident surface 12 of the edge 11, and is notched 14. The light is totally reflected by the reflective surface 13 and travels through a predetermined interior of the aperture 9 and is guided from the predetermined position of the aperture 9 to the external absorbent material 15.

  The laser beam Ra guided to the absorber 15 becomes heat and heats the absorber 15. At the same time, the absorber 15 is cooled by the cooler 16, so that the temperature of the absorber 15 is prevented from rising.

  In this way, the laser beam Ra limited by the edge 11 of the aperture 9 travels through a predetermined inside of the aperture 9 instead of being reflected and scattered, and is guided from a predetermined position of the aperture 9 to the outside. The light Ra does not hit a member located around the aperture 9 due to reflection and scattering, and heating of the surrounding members can be prevented.

  If a non-reflective coating that does not reflect the laser beam Ra is provided on the vertical incident surface 12, the laser beam Ra is reflected at the incident surface 12 when the excess laser beam Ra is incident on the edge 11 of the aperture 9. Therefore, reflection and scattering of the laser beam Ra can be reliably prevented.

  Furthermore, if the aperture 9 is provided with an absorbing material 15 that absorbs the heat of the limited laser beam Ra, the laser beam Ra guided into the aperture 9 is absorbed by the absorbing material 15, so that the heating of the edge portion 11 is performed. Can be prevented.

  Furthermore, if the cooler 16 for preventing the absorbent 15 from being heated is provided, the absorbent 15 can also be prevented from being heated, so that the edge 11 and the absorbent 15 can be reliably prevented from being heated.

A second reference example of the aperture will be described with reference to FIG. 3. The aperture 17 of the second reference example is configured such that the edge 11 of the aperture 9 of the first reference example is located at an intermediate position of the notch 14 from the one incident surface 12. The shape up to the reflecting surface 13 is used.

  More specifically, the edge portion 19 of the opening 18 has a side surface on the emission side of the laser beam R formed on the incident surface 20 perpendicular to the laser beam R and is provided with a non-reflective coating. On the opposite side, a sloped notch 22 is formed so as to form a reflection surface 21 that totally reflects the laser beam R toward a predetermined interior.

The aperture 17 is made of a material such as optical glass that is transmissive, like the aperture 9 of the first reference example , and preferably has a high light transmission and high thermal conductivity such as sapphire and YAG. Is desirable.

  On the other hand, the aperture 17 is provided with an absorbing material such as metal painted in black so as to absorb heat, and the absorbing material is provided with a cooler.

Hereinafter, the operation of the second reference example will be described.

  When the laser beam R passes through the transmission line, the amplifier, and the like only from one direction and the laser beam R is passed through the opening 18 of the aperture 17 to reduce the beam diameter, the limited excess laser beam Ra is The light enters the predetermined interior of the material that is transmitted from the vertical incident surface 20 of the edge portion 19, is totally reflected by the reflection surface 21 of the notch 22 on the opposite side, travels through the predetermined interior of the aperture 17, and from the predetermined position of the aperture 17. Guided to external absorbent material.

  Further, the laser light Ra guided to the absorber becomes heat and heats the absorber. At the same time, the absorber is cooled by a cooler, so that the temperature of the absorber is prevented from rising.

Thus, the laser light Ra that is limited by the edge 19 of the aperture 17, the reflection, since guided to the outside from a predetermined position of the aperture 17 proceeds a predetermined internal aperture 17 instead of scattering, the first reference The effect almost the same as the example can be obtained.

To explain the first example of an aperture in the embodiment of the present invention with reference to FIG. 4, the aperture 23 of the first embodiment is a modification of the shape of the edge portion 11 in the aperture 9 of the first embodiment.

  The edge 25 of the opening 24 of the aperture 23 is formed in a wedge shape with both surfaces facing the opening. The wedge-shaped specific shape is such that both surfaces are the incident surfaces 26 and the laser light Ra is transmitted from the one incident surface 26 to the aperture 23. And is reflected at a predetermined angle at the other incident surface 26 on the other side.

Here, the material of the aperture 23 is a transparent material such as optical glass like the aperture 9 of the first reference example , and preferably has a high light transmittance and a high thermal conductivity such as sapphire and YAG. .

Further, the aperture 23 is provided with an absorbing material such as a metal painted in black so as to absorb heat in the same manner as the aperture 9 of the first reference example , and the absorbing material is provided with a cooler.

The operation of the first example of the embodiment of the present invention will be described below.

  When the beam diameter is narrowed by passing the laser beam R through the opening 24 of the aperture 23, the limited excess laser beam Ra is incident on the inside of the aperture 23 from one wedge-shaped incident surface 26, and on the opposite side of the wedge shape. The light is reflected by the incident surface 26, travels through a predetermined inside of the aperture 23, and is guided to the outside from a predetermined position of the aperture 23.

Here, although the aperture 23 of the first example reflects about 5% of the laser light R at the incident surface 26, heating of the members located around the aperture 23 can be sufficiently prevented.

  Next, the laser light Ra guided to the absorbing material becomes heat and heats the heat absorbing material, but at the same time the heating material is cooled by the cooler, thereby preventing the temperature of the heating material from rising.

  In this way, the laser beam Ra limited by the edge 25 of the aperture 23 travels through a predetermined inside of the aperture 23 instead of being reflected and scattered, and is guided to the outside from a predetermined position of the aperture 23. The light Ra does not hit a member located around the aperture 23 due to reflection and scattering, and heating of the surrounding members can be prevented. Further, since the edge 25 of the aperture 23 has a simple wedge shape, it can be easily molded, and the manufacturing cost can be reduced.

Furthermore, the action of the first example of the embodiment of the present invention can obtain the same action as the first reference example .

  It should be noted that the aperture of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention.

2 Laser rod 23 Aperture 24 Aperture 25 Edge 26 Incident surface R Laser light Ra Laser light

Claims (3)

An aperture that narrows the beam diameter of the laser beam through the opening with respect to the laser beam emitted from the axial end of the laser rod. The aperture is made of a material that transmits the laser beam and restricts excess laser beam. Both sides of the edge for narrowing the beam diameter are wedge-shaped toward the opening, and the laser beam incident on the inside from one incident surface is reflected toward the predetermined inside by the opposite incident surface. aperture. The aperture according to claim 1, further comprising an absorber that absorbs heat of the limited laser beam. The aperture according to claim 2, further comprising a cooler that prevents heating of the absorbent material .

Images