Laser diode/lens assembly

• US 5,615,052 A
• Filed: 11/01/1994
• Issued: 03/25/1997
• Est. Priority Date: 04/16/1993
• Status: Expired due to Fees

• Current Assignee: Bruce W. Mccaul
• Original Assignee: Bruce W. Mccaul
• Inventors: Doggett, David E.
• Primary Examiner(s): Sugarman, Scott J.
• Application Number:
  US08/332,991
• Time in Patent Office: 875 Days
• Field of Search: 359/642, 359/811, 372/34, 372/36, 372/101
• US Class Current: 359/811
• CPC Class Codes: G01N 2021/399 Diode laser
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 21/39 using tunable lasers
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 7/02 for lenses supports for magnifying lenses G02B25/002
• CPC Class Codes: H01S 5/02212 Can-type, e.g. TO-CAN housings with emission along or parallel to symmetry axis
• CPC Class Codes: H01S 5/02253 using lenses
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/02415 by using a thermo-electric cooler [TEC], e.g. Peltier element
• CPC Class Codes: H01S 5/0683 by monitoring the optical output parameters

Abstract

A laser diode/lens assembly wherein a lens (or multi-lens assembly) is immovably adhered to a housing of a laser diode package. The laser diode package may be a metal can style package having a substantially transparent window portion through which laser radiation is emitted when a laser diode inside the housing is supplied with current. The lens may be immovably fixed to an outer surface of this window so that a central axis of a beam of laser radiation emerging from the lens has a desired spatial relationship with a reference surface of the housing. An adhesive such as an epoxy adhesive which is cured under exposure to ultraviolet radiation may be used to freeze the lens in place to the window when the lens is correctly positioned. In accordance with some embodiments of the present invention, a lens is positioned in three dimensions (X, Y and Z) and then fixed in three dimensional space with respect to a laser diode housing. Fixing the position of the lens in the Z dimension at a desired location allows the focal point of the laser diode/lens assembly to be set so as not to focus laser radiation on a window of a gas spectroscopy device.

Claims

1. A method, comprising:

moving a lens into a position with respect to a laser diode housing such that a minimum distance between said laser diode housing and said lens changes during said moving, an amount of uncured adhesive being in contact with both said lens and said housing during said moving; and

after said moving, curing said adhesive to fix said lens in said position with respect to said housing.

2. The method of claim 1, wherein said lens is moved in a direction Z substantially collinear with an axis of a beam of laser radiation, said beam of laser radiation being emitted from a laser diode disposed inside said laser diode housing.

3. The method of claim 2, wherein said lens is also moved in a second direction substantially perpendicular to said direction Z when said amount of uncured adhesive is in contact with both said lens and said housing.

4. The method of claim 1, further comprising:

grasping said lens using a partial vacuum.

5. The method of claim 4, wherein said moving involves:

moving said lens with respect to said laser diode housing using a micropositioner.

6. The method of claim 1, further comprising:

gripping a gripping extension of said lens.

7. The method of claim 6, wherein said moving involves:

moving said lens with respect to said laser diode housing using a micropositioner.

8. The method of claim 1, wherein said moving involves detecting a location where a beam of laser radiation is incident upon a detector, said beam of laser radiation passing from inside said laser diode housing, through said lens, and onto said detector.

9. The method of claim 8, wherein said lens is moved with respect to said laser diode housing until said location has a desired spatial relationship with respect to said laser diode housing.

10. The method of claim 1, wherein said moving involves moving said lens with respect to said laser diode housing until a spot size of laser radiation detected on a detector has a desired area, said laser radiation passing from inside said laser diode housing, through said lens, and onto said detector.

11. Structure for positioning a lens with respect to a laser diode housing when said lens is disposed in an amount of uncured adhesive, comprising:

a laser diode housing holding member, said laser diode housing holding member being adapted to removably hold said laser diode housing;

a lens holding member, said lens holding member being controllable to move said lens with respect to said laser diode housing member in the three dimensions (X, Y and Z) of three dimensional space when said uncured adhesive is in contact with both said lens and said laser diode housing, said lens holding member being adapted to be disengaged from said lens after said amount of uncured adhesive is cured; and

a beam detecting device disposed to detect laser radiation emitted from a laser diode disposed inside said laser diode housing while said lens holding member is in contact with said lens but before said amount of uncured adhesive is cured.

12. The structure of claim 11, wherein said lens holding member has a window through which said laser radiation passes.

13. The structure of claim 12, wherein said lens holding member has a partial vacuum chamber.

14. The structure of claim 11, wherein said lens holding member comprises a three-axis micropositioner.

15. The structure of claim 12, further comprising an ultraviolet radiation source disposed to expose said amount of uncured adhesive to ultraviolet radiation, said amount of adhesive being cured by ultraviolet radiation passing through said window.

16. The structure of claim 11, wherein said laser diode housing holding member comprises electrical conductors for supplying electrical power to said laser diode when said lens is being moved with respect to said laser diode housing.

17. Structure, comprising:

means for moving a lens with respect to a laser diode housing, said lens moving in the three dimensions (X, Y and Z) of three dimensional space, an amount of uncured adhesive contacting both said lens and said laser diode housing during said moving; and

a beam detecting device detecting laser radiation emitted from a laser diode disposed inside said laser diode housing when said adhesive is uncured.

18. The structure of claim 17, wherein said laser diode housing has a window, said window having an outside surface disposed in a plane, said dimensions X and Y defining said plane, said dimension Z being perpendicular to said plane.