Annular illumination device

• US 4,476,519 A
• Filed: 08/10/1982
• Issued: 10/09/1984
• Est. Priority Date: 08/13/1981
• Status: Expired due to Fees

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Hayamizu, Toshisada
• Primary Examiner(s): Nelson, Peter A.
• Application Number:
  US06/406,913
• Time in Patent Office: 791 Days
• Field of Search: 362/32, 362/259, 350/96.18, 350/96.24, 330/4.3
• US Class Current: 362/554
• CPC Class Codes: G02B 21/14 affording illumination for phase-contrast observation

Abstract

An annular illumination device comprising a tubular light transmitter, a light source means able to project parallel light rays onto an entrance end face of the tubular light transmitter from a direction intersecting diagonally with the entrance end face and a light collecting lens collecting conical light bundle coming out of an exit end face of the tubular light transmitter to form an image of an annular light in order to make it possible to make a bright efficient annular illumination. The angle formed by the parallel light rays with the entrance end face of the tubular light transmitter can be varied in order to vary the diameter of the image of the annular light.

Claims

1. An annular illumination device comprising a light source means capable of projecting substantially parallel light rays, a tubular light transmitter having its entrance end face and its exit end face both inclined to said light rays and capable of transmitting said light rays with its inner face reflections, a light collecting lens arranged so that its front focal point coincides with the exit end face of said tubular light transmitter and capable of collecting a conical light bundle projected out of the exit end face of said tubular light transmitter to form an image of an annular light, and a condenser lens arranged so that its front focal point coincides with a rear focal point of said light collecting lens.

2. An annular illumination device according to claim 1 wherein said light source means can move to vary the angle formed by said light rays with said entrance end face to vary the diameter of the image of said annular light.

3. An annular illumination device according to claim 1 or 2 wherein said tubular light transmitter is a member selected from the group consisting of optical fibers, a glass bar and a hollow pipe finished on the inner surface so as to be well reflective.

4. An annular illumination device according to claim 1 or 2 wherein said tubular light transmitter is formed of flexible optical fibers to vary the angle formed by said light rays with said entrance end face to vary the diameter of the image of said annular light.

5. An annular illumination device according to claim 1 or 2 wherein said light source means is a laser light source.

6. An annular illumination device according to claim 1 wherein said light source means consists of a xenon discharge tube as a light source, a collector lens and a relay lens.

7. An annular illumination device according to claim 1 or 2 wherein said tubular light transmitter is formed of flexible optical fibers to vary the angle formed by said light rays with said entrance end face to vary the diameter of the image of said annular light and wherein said light source means consists of a xenon discharge tube as a light source, a collector lens and a relay lens.