Solid state laser apparatus and laser machining apparatus

• US 5,557,628 A
• Filed: 04/28/1994
• Issued: 09/17/1996
• Est. Priority Date: 09/24/1993
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Seguchi, Masaki, Yamamoto, Takashi, Kuba, Kazuki, Ishimori, Akira
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): Wise, Robert E.
• Application Number:
  US08/233,416
• Time in Patent Office: 873 Days
• Field of Search: 372/70, 372/34, 372/35, 372/36, 372/40, 372/41, 372/98, 372/99
• US Class Current: 372/70
• CPC Class Codes: B23K 26/06 Shaping the laser beam, e.g. by masks or multi-focusing
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/0643 comprising mirrors
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: B23K 26/0652 comprising prisms
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: H01S 3/025 of solid state lasers, e.g. housings or mountings
• CPC Class Codes: H01S 3/0407 Liquid cooling, e.g. by water
• CPC Class Codes: H01S 3/042 for solid state lasers H01S3/0401 takes precedence
• CPC Class Codes: H01S 3/06 Construction or shape of active medium
• CPC Class Codes: H01S 3/0606 with polygonal cross-section, e.g. slab, prism H01S3/0604 takes precedence
• CPC Class Codes: H01S 3/08059 Constructional details of the reflector, e.g. shape mirrors in general G02B5/08; mountings for mirrors G02B7/18
• CPC Class Codes: H01S 3/08072 Thermal lensing or thermally induced birefringence; Compensation thereof
• CPC Class Codes: H01S 3/08095 Zig-zag travelling beam through the active medium
• CPC Class Codes: H01S 3/093 focusing or directing the excitation energy into the active medium
• CPC Class Codes: H01S 3/2308 Amplifier arrangements, e.g. MOPA
• CPC Class Codes: H01S 3/2325 Multi-pass amplifiers, e.g. regenerative amplifiers
• CPC Class Codes: H01S 3/2383 Parallel arrangements

Abstract

A solid state laser apparatus and a laser machining apparatus are provided to provide high power laser beam having an excellent condensing performance at high efficiency and with high reliability. In the solid state laser apparatus, a recess is provided in a supporter disposed on a slab side surface at an excitation area corresponding portion. A high reflectance body having a cooling water filtrating groove is disposed in the recess to contact with a slab facing surface with pressure. The supporter contacts slab longitudinal both ends with pressure through a silicon rubber plate which is transparent to excitation light. A transparent silicon rubber O-ring is disposed to extend over an entire peripheral portion of a plane formed by a slab surface including the supporter pressure contacting porting and the supporter so as to seal cooling water and elastically support the slab.

Claims

1. A solid state laser apparatus comprising:

a laser medium having a rectangular plate form including upper and lower smooth surfaces extending substantially parallel to each other, right and left side surfaces extending substantially perpendicular to said smooth surfaces, and back and forth end surfaces for entrance/exit of a laser beam;

a pair of supporters disposed on the right and left sides of said laser medium;

a frame integrally containing said supporters;

a light source exciting said laser medium;

a condenser to condense excitation light from said light source for irradiation of said laser medium; and

cooling means for cooling said laser medium by at least one of said smooth surfaces thereof;

wherein an irregularity is formed in said supporter at an inner surface opposed to said side surfaces of said laser medium or at a back surface, and a cooling material is filled into a clearance of said irregularity.

2. A solid state laser apparatus according to claim 1, wherein a groove in a thickness direction of said laser medium is provided in an inner surface of said supporter to form said irregularity.

3. A solid state laser apparatus according to claim 1, wherein a distribution in a longitudinal direction or in a vertical direction of said laser medium is provided for a pitch, an area, or a depth of said irregularity.

4. A solid state laser apparatus according to claim 1, wherein cooling of said laser medium is performed by coolant filled to contact each smooth surface, and a pressure difference is provided between coolants on the upper and lower sides of said laser medium so as to generate a flow of said coolant in a concave portion in an inner surface of said supporter.

5. A solid state laser apparatus according to claim 1, wherein said irregularity in the inner surface of said supporter is formed by a groove extending diagonally to a thickness direction of said laser medium.

6. A solid state laser apparatus according to claim 1, wherein said supporter has high reflectance to excitation light.

7. A solid state laser apparatus comprising:

a laser medium having a rectangular plate form including upper and lower smooth surfaces extending substantially parallel to each other, right and left side surfaces extending substantially perpendicular to said smooth surfaces, and back and forth end surfaces for entrance/exit of a laser beam;

a pair of supporters disposed on the right and left sides of said laser medium;

a frame integrally containing said supporters;

a light source exciting said laser medium;

a condenser to condense excitation light from said light source for irradiation of said laser medium; and

cooling means for cooling said laser medium by at least one of said smooth surfaces thereof;

wherein said pair of supporters is made of a plurality of different materials.

8. A solid state laser apparatus comprising:

a laser medium having a rectangular plate form including upper and lower smooth surfaces extending substantially parallel to each other, right and left side surfaces extending substantially perpendicular to said smooth surfaces, and back and forth end surfaces for entrance/exit of a laser beam;

a pair of supporters disposed on the right and left sides of said laser medium;

a frame integrally containing said supporters;

a light source exciting said laser medium;

a condenser to condense excitation light from said light source for irradiation of said laser medium;

cooling means for cooling said laser medium by at least one of said smooth surfaces thereof; and

means for contacting with pressure said supports with the side surfaces of said laser medium to stabilize a thermal boundary condition at the side surfaces of said laser medium.

9. A solid state laser apparatus according to claim 8, wherein said supporter contacts said laser medium with pressure through an elastic body.

10. A solid state laser apparatus according to claim 9, wherein said elastic body is made of a material which is transparent to excitation light.

11. A solid state laser apparatus according to claim 9, wherein said elastic body is adhered to the supporter.

12. A solid state laser apparatus according to claim 8, wherein no inclusion is interposed between an excitation area of said laser medium and a supporter.

13. A solid state laser apparatus according to claim 8, wherein a substance having elasticity is filled into a clearance between a chamfer portion of a corner portion in the vicinity of a seal position of said laser medium and said elastic body.

14. A solid state laser apparatus according to claim 8, wherein a chamfer dimension of a corner portion in the vicinity of a seal position of said laser medium is set at 0.3 mm or less.

15. A solid state laser apparatus according to claim 8, wherein a screw hole is provided in said frame at a position opposed to the supporter to extend substantially perpendicular to a back surface of said supporter, and a distal end of a screw member fitted into the screw hole pushes said back surface of said supporter to contact said supporter with said laser medium with pressure.

16. A solid state laser apparatus according to claim 15, wherein an elastic body is provided between said distal end of said screw member and said back surface of said supporter.

17. A solid state laser apparatus according to claim 15, wherein a plate body is disposed on a back surface of said supporter.

18. A solid state laser apparatus according to claim 17, wherein an elastic body is disposed between said supporter and a plate body.

19. A solid state laser apparatus according to claim 18, wherein said plate body is made of a material having extremely lower elasticity than that of said elastic body.

20. A solid state laser apparatus comprising:

a laser medium having a rectangular plate form including upper and lower smooth surfaces extending substantially parallel to each other, right and left side surfaces extending substantially perpendicular to said smooth surfaces, and back and forth end surfaces for entrance/exit of a laser beam;

a pair of supporters disposed on the right and left sides of said laser medium;

a frame integrally containing said supporters;

a light source exciting said laser medium;

a condenser to condense excitation light from said light source for irradiation of said laser medium; and

cooling means for cooling said laser medium by at least one of said smooth surfaces thereof;

wherein a recess is provided in said supporter at an excitation area corresponding position opposed to said laser medium, and a member having high reflection to excitation light being disposed in said recess.

21. A solid state laser apparatus according to claim 20, wherein said high reflectance member contacts a side surface of said laser medium with pressure.

22. A solid state laser apparatus according to claim 21, wherein an elastic body is disposed between a back surface of said high reflectance member and a recess, and elasticity of said elastic body contacts said high reflectance member with a side surface of said laser medium with pressure.

23. A solid state laser apparatus according to claim 21, wherein a screw hole is provided in a recess of said supporter to extend substantially perpendicular to a side surface of a laser medium, and a distal end of a screw member fitted into said screw hole contacts said high reflectance member with the side surface of said laser medium with pressure.

24. A solid state laser apparatus according to claim 23, wherein an elastic body is interposed between said high reflectance member and the distal end of said screw member.

25. A solid state laser apparatus according to claim 23, wherein a plate body is disposed on a back surface of said high reflectance member.

26. A solid state laser apparatus according to claim 25, wherein an elastic body is interposed between said high reflectance member and a plate body.

27. A solid state laser apparatus according to claim 26, wherein said plate body is made of a material having extremely lower elasticity than that of said elastic body.

28. A solid state laser apparatus according to claim 20, wherein said high reflection member is integrally formed with a condenser.

29. A solid state laser apparatus according to claim 20, wherein an irregularity is formed in said member having high reflection to excitation light at an inner surface opposed to said side of said laser medium or at a back surface, a cooling material is filled into a clearance of said irregularity.

30. A solid state laser apparatus according to claim 29, wherein a groove in a thickness direction of said laser medium is provided in the inner surface of said member having high reflection to excitation light to form said irregularity.

31. A solid state laser apparatus according to claim 29, wherein a distribution in a longitudinal direction or in a vertical direction of said laser medium is provided for a pitch, an area, or a depth of said irregularity.

32. A solid state laser apparatus according to claim 29, cooling of said laser medium is performed by coolant to contact each smooth surface, and a pressure difference is provided between coolants on the upper and lower sides of said laser medium so as to generate a flow of said coolant in a concave portion of the inner surface of said member having high reflection to excitation light.

33. A solid state laser apparatus according to claim 29, wherein the irregularity in the inner surface of said member having high light reflection to excitation light is formed by a groove extending diagonally to a thickness direction of said laser medium.

34. A solid state laser apparatus according to claim 20, wherein said member having high reflection to excitation light is made of a plurality of different materials.