Adjustable mount for large mirrors

• US 4,681,408 A
• Filed: 04/28/1986
• Issued: 07/21/1987
• Est. Priority Date: 04/28/1986
• Status: Expired due to Term

• Current Assignee: ASML Holding NV
• Original Assignee: Perkinelmer Incorporated
• Inventors: Huse, Richard, Ahmad, Anees
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/856,881
• Time in Patent Office: 449 Days
• Field of Search: 350/611, 350/609, 350/607, 350/633, 350/486, 248/481, 248/484, 248/485
• US Class Current: 359/848
• CPC Class Codes: G02B 7/183 specially adapted for very large mirrors, e.g. for astronomy, or solar concentrators

Abstract

A mirror mounting apparatus which includes three tangent bars through which a mirror is mounted to a housing. One end of each of the tangent bars is mounted to the housing through a first spherical bearing while the second end of the tangent bar is mounted to the mirror through a second spherical bearing. The first spherical bearing has an axis perpendicular to the plane of the mirror. The second spherical bearing is oriented to have an axis perpendicular to both the axis of the first spherical bearing and to a line tangent to the point of attachment on the outer circumference of the mirror of the tangent bar.

Claims

1. A mirror mounting apparatus comprising:

a mirror;

a housing;

three individual tangent bars having a first end and a second end;

each of said three individual tangent bars having the first end thereof rotatably mounted to said housing through a first spherical bearing and the second end thereof rotatably mounted to said mirror through a second spherical bearing;

the first spherical bearing having an axis perpendicular to the plane of said mirror; and

the second spherical bearing having an axis perpendicular to both the axis of said first spherical bearing and to a line tangent to the point of contact on said outer circumference of said mirror of said tangent bar.

2. A mirror mounting apparatus as claimed in claim 1 wherein said second spherical bearing is rotatably mounted to said mirror through a button, said button being of a material having a low coefficient of thermal expansion.

3. A mirror mounting apparatus as claimed in claim 1 which further comprises:

adjustment means to move said mirror along its optical axis or to tilt said mirror about its optical axis.

4. A mirror mounting apparatus as claimed in claim 3 wherein said adjustment means comprises:

micrometer means affixed to said housing operable in cooperation with the second end of said tangent bar to move said mirror out of its plane.

5. A mirror mounting apparatus as claim in claim 1 which further comprises suspension means for preventing distortions of said mirror due to the weight of said mirror.

6. A mirror mounting apparatus as claimed in claim 5 wherein said suspension means comprises:

a plurality of springs, spaced about the circumference of said mirror, having a first end and a second end;

the first end of said plurality of springs being mounted to said housing through tension adjusting means; and

the second end of said plurality of springs being mounted to said mirror.