Optical integrator means for intensity modification of Gaussian beam

• US 4,656,562 A
• Filed: 09/13/1985
• Issued: 04/07/1987
• Est. Priority Date: 09/13/1985
• Status: Expired due to Term

• Current Assignee: Santa Barbara Research Center
• Original Assignee: Santa Barbara Research Center
• Inventors: Sugino, Paul S.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Cox, D. M.
• Application Number:
  US06/776,189
• Time in Patent Office: 571 Days
• Field of Search: 362/235, 362/236, 362/244, 362/246, 362/32, 362/339, 362/268, 362/26, 362/27, 362/326, 350/96.1, 350/96.28, 350/168, 350/286, 350/287
• US Class Current: 362/552
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0047 for use with a light source G02B19/009, G02B19/0095 take precedence; details of lighting devices in general F21V; non-semiconductor lasers having optical devices external to the laser cavity H01S3/005
• 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 27/0994 Fibers, light pipes optical fibers per se G02B6/02

Abstract

Optical projection apparatus is disclosed for generating a planar light beam of substantially uniform intensity from a nonplanar multi-element light source projecting a beam having a generally Gaussian intensity distribution. In the preferred embodiment, an optical integrator rod having a faceted end face is used to essentially invert the cross-sectional intensity of the beam entering the entrance face so that when the beam leaves the exit face it has a generally uniform intensity. The body of the integrator rod serves to homogenize the nonplanar source into an exiting beam having substantially planar characteristics.

Claims

1. In an optical projection apparatus having a multi-element source projecting a beam having a generally Gaussian intensity distribution along an optical axis towards a target plane, with the beam including a marginal ray and an axial ray, wherein the improvement comprises:

a rod of optically transmitting material disposed coaxially with the optical axis, means defining an entrance face and an exit face for the rod, said means including different geometric configurations for the entrance and exit faces, adapted for inverting the intensity of the beam entering the entrance face such that marginal rays of the beam leave the exit face substantially parallel to the optical axis and wherein axial rays are redistributed outwardly so as to diverge from the exit face thereby providing the beam with a generally uniform intensity as it leaves the exit face.

2. The improvement of claim 1 wherein the entrance face of the rod is faceted and the exit face is substantially planar.

3. The improvement of claim 2 wherein the entrance face is defined by four triangular shaped surfaces meeting at an apex disposed substantially coaxially with the optical axis.

4. Optical projection apparatus for generating a light beam of substantially uniform intensity from a multi-element, nonplanar source projecting a beam along an optical axis having a generally Gaussian intensity distribution, with the beam including a marginal ray and an axial ray, said apparatus comprising:

a rod of optically transmitting material having its length disposed coaxially with the beam projected from the source, said rod having a substantially rectangular cross-section throughout its length, means defining an entrance and exit face for the rod, said means including different geometrical configurations for the entrance and exit faces, adapted to invert the intensity of the beam entering the entrance face such that marginal rays of the beam leave the exit face substantially parallel to the optical axis and wherein axial rays are redistributed outwardly so as to diverge from the exit face thereby producing a beam at the exit face in the form of a plane source of forwardly directed light having a generally uniform intensity distribution.

5. The apparatus of claim 4 wherein the entrance face has faceted surfaces and the exit face is substantially planar.

6. The apparatus of claim 5 wherein the entrance face is defined by four triangular shaped surfaces of equal size meeting at an apex disposed along the optical axis, adapted to generally make a marginal ray from the source leave the exit face of the rod parallel to the optical axis and to make an axial aray from the source leave the exit face of the rod disposed toward the periphery of the exit face of the rod at an angle with respect to the optical axis.

7. The apparatus of claim 6 wherein said rod is constructed of a single piece of quartz material.

8. In an optical projection apparatus having a multi-element source projecting a beam having a generally Gaussian intensity distribution along an optical axis towards a target plane, wherein the improvement comprises:

a rod of optically transmitting material disposed coaxially with the optical axis;

said rod having an entrance face defined by four triangularly-shaped surfaces meeting at an apex disposed substantially coaxially along the optical axis, and wherein said rod has an exit face of a different geometric configuration cooperating with the configuration of the entrance face to effectively invert the intensity of the beam entering the entrance face thereby providing the beam with a generally uniform intensity as it leaves the exit face.

9. Optical projection apparatus for generating a light beam of substantially uniform intensity from a multi-element, nonplanar source projecting a beam along an optical axis having a generally Gaussian intensity distribution, said apparatus comprising:

a rod of optically transmitting material having its length disposed coaxially with the beam projected from the source, said rod having a substantially rectangular cross-section throughout its length between an entrance face and an exit face, said entrance face being defined by four triangularly-shaped surface of equal size meeting at an apex disposed along the optical axis, and said entrance face being substantially planar whereby said configurations of said entrance and exit faces cooperate to generally make a marginal ray from the source leave the exit face of the rod parallel to the optical axis and to make an axial ray from the source leave the exit face of the rod disposed toward the periphery of the exit face of the rod at an angle with respect to the optical axis, thereby producing a beam at the exit face in the form of a plane source of forwardly-directed light having a generally uniform intensity distribution.