Lensless laser focusing device

• US 6,752,501 B2
• Filed: 04/19/2002
• Issued: 06/22/2004
• Est. Priority Date: 04/23/2001
• Status: Expired due to Fees

• Current Assignee: Dee E. Willden
• Original Assignee: Dee E. Willden
• Inventors: Willden, Dee E.
• Primary Examiner(s): PRITCHETT, JOSHUA L
• Application Number:
  US10/126,907
• Publication Number:
  US 20020154421A1
• Time in Patent Office: 795 Days
• Field of Search: 385/31, 385/32, 385/33, 385/34, 354/838
• US Class Current: 359/838
• CPC Class Codes: B01D 59/34 Separation by photochemical methods
• CPC Class Codes: G02B 27/09 Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/0977 Reflective elements
• CPC Class Codes: G02B 27/0983 being curved

Abstract

A lensless focusing device for receiving an unfocused laser beam and discharging a focused laser beam. The focusing device includes a solid body having an open interior defined by a conical inner wall extending from an inlet opening to a discharge opening. The conical inner wall is a polished or reflective surface that directs the input laser beam toward the discharge opening. The solid body can include a heating element to raise the temperature of the solid body relative to ambient.

Claims

1. An apparatus for focusing an input laser beam, the apparatus comprising:

a solid body extending between an inlet end and a discharge end;

an inlet opening formed in the inlet end of the solid body, the inlet opening defining an entry area greater than the cross-sectional area of the input laser beam such that the entire input laser beam enters the inlet opening;

a discharge opening formed in the discharge end of the solid body, the discharge opening having an exit area less than the cross-sectional area of the input laser beam;

a conical inner wall formed in the solid body to define an open interior, the conical inner wall extending from the inlet opening to the discharge opening, wherein the conical inner wall includes a polished surface that reflects the input laser beam toward the discharge opening; and

a heating element positioned in contact with the solid body, wherein the heating element is operable to elevate the temperature of the solid body including the conical inner wall to increase the reflectivity of the conical inner wall.

2. The apparatus of claim 1 wherein the heating element is positioned within the solid body.

3. The apparatus of claim 1 wherein the discharge opening is circular.

4. The apparatus of claim 1 wherein the solid body is formed from a metallic material.

5. The apparatus of claim 1 wherein the conical inner wall is continuously tapered from the inlet opening to the discharge opening.

6. The apparatus of claim 1 wherein the discharge opening includes an outlet stencil defining an outlet shape for the focused laser beam.

7. An apparatus for focusing an input laser beam, the apparatus comprising:

a solid body extending between an inlet end and a discharge end;

an inlet opening formed in the inlet end of the solid body, the inlet opening defining an entry area greater than the cross-sectional area of the input laser beam such that the entire input laser beam enters the inlet opening;

a discharge opening formed in the discharge end of the solid body, the discharge opening having an exit area less than the cross-sectional area of the input laser beam; and

a conical inner wall formed in the solid body to define an open interior, the conical inner wall extending from the inlet opening to the discharge opening, wherein the conical inner wall includes a polished surface that reflects the input laser beam toward the discharge opening, wherein the conical inner wall of the solid body includes a plurality of steps, each step decreasing the internal diameter of the open interior from the inlet opening to the discharge opening, wherein the input laser beam is reflected off of the plurality of steps toward the discharge opening.

8. The apparatus of claim 7 further comprising a heating element positioned in contact with the solid body, wherein the heating element is operable to elevate the temperature of the solid body including the conical inner wall to increase the reflexivity of the conical inner wall.

9. The apparatus of claim 8 wherein the heating element is positioned within the solid body.

10. The apparatus of claim 9 wherein each of the steps includes a polished surface.

11. A method of focusing an input laser beam without the use of optics, the method comprising the steps of:

providing a focusing device having a solid body extending between an inlet end and a discharge end;

forming an open interior within the solid body for focusing the input laser beam, the open interior being defined by a conical inner wall extending between an inlet opening formed at the inlet end of the solid body and a discharge opening formed at the discharge end of the solid body;

positioning the focusing device such that the input laser beam is received within the inlet opening, wherein the inlet has an entry area greater than the cross-sectional area of the input laser beam;

discharging a focused laser beam from the discharge opening, wherein the discharge opening defines an exit area that is less than the cross-sectional area of the input laser beam;

positioning a heating element in contact with the solid body; and

operating the heating element to elevate the temperature of the solid body including the conical inner wall to increase the reflexivity of the conical inner wall.

12. The method of claim 11 wherein the heating element is positioned within the solid body.

13. The method of claim 11 wherein the conical inner wall is formed from a polished surface that reflects the input laser beam toward the discharge opening.

14. The method of claim 11 further comprising the step of forming the discharge opening in a shape to define the shape of the focused laser beam.

15. A method of focusing an input laser beam without the use of optics, the method comprising the steps of:

providing a focusing device having a solid body extending between an inlet end and a discharge end;

forming an open interior within the solid body for focusing the input laser beam, the open interior being defined by a conical inner wall extending between an inlet opening formed at the inlet end of the solid body and a discharge opening formed at the discharge end of the solid body;

forming a plurality of steps along the conical inner wall, each step decreasing the internal diameter of the open interior from the inlet opening to the discharge opening;

positioning the focusing device such that the input laser beam is received within the inlet opening and reflected off of the plurality of steps formed along the conical inner wall toward the discharge end, wherein the inlet opening has an entry area greater than the cross-sectional area of the input laser beam; and

discharging a focused laser beam from the discharge opening, wherein the discharge opening defines an exit area that is less than the cross-sectional area of the input laser beam.

16. The method of claim 15 further comprising the steps of:

positioning a heating element in contact with the solid body; and

operating the heating element to elevate the temperature of the solid body including the conical inner wall to increase the reflexivity of the conical inner wall.