Optical position measuring apparatus

• US 4,782,239 A
• Filed: 04/01/1986
• Issued: 11/01/1988
• Est. Priority Date: 04/05/1985
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nippon Kogaku K. K. (Nikon Corporation)
• Inventors: Hamada, Tomohide, Hirose, Hideo
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): Shami, Khaled
• Application Number:
  US06/846,950
• Time in Patent Office: 945 Days
• Field of Search: 250/201 AF, 250/561, 354/403, 356/1, 356/4, 356/375
• US Class Current: 250/559.38
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver

Abstract

Apparatus for measuring the distance to an object comprising projection means for projecting a radiation beam onto the object including a radiation generating means and a first optical system, and detection means for detecting the radiation beam reflected from the object including radiation detecting means having a radiation-receiving surface for detecting the intensity distribution of the radiation on said radiation-receiving surface and a second optical system for guiding at least a portion of the reflected radiation beam from the object to said radiation-receiving surface, an optically conjugated relation being held between said radiation-receiving surface and an area of the optical axis of the first optical system.

Claims

1. Apparatus for measuring the distance to an object comprising:

projection means for projecting a radiation beam onto the object, said projection means including a radiation generating means and a first optical system for projecting the radiation beam on the surface of said object in accordance with said radiation, said first optical system having a lens component; and

detectilon means for detecting the radiation beam reflected from the object, said detection means including radiation detecting means having a radiation-receiving surface for detecting the intensity distribution of the radiation on said radiation-receiving surface, and a second optical system cooperating with said lens component for guiding at least a portion or the reflected radiation beam from the object to said radiation-receiving surface, said lens component and said second optical system being so disposed as to bring said radiation-receiving surface into an optically conjugated relation with a line segment of the optical axis of the first optical system along which the object is located, said radiation-receiving surface being disposed so that a projection image of said radiation-receiving surface formed by said lens component intersects the optical axis of said lens component substantially at right angles and so that the position of said radiation beam on said radiation-receiving surface changes linearly in accordance with an amount of displacement of the object along said line segment of the optical axis of said first optical system.

2. Apparatus according to claim 1, wherein siad radiation detecting means generates a signal corresponding to the intensity distribution of the radiation on said radiation-receiving surface and said apparatus further comprises means for detecting the position of the object in a direction along the optical axis of said first optical system in accordance with said signal.

3. Apparatus according to claim 2, wherein said second optical system guides at least a portion of the reflected radiation beam from the object to the light-receiving surface through said lens component.

4. Apparatus according to claim 2, wherein said lens component guides at least a portion of the reflected radiation beam from the object to the radiation-receiving surface through said second optical system.

5. Apparatus for measuring the distance to an object comprising:

projection means for projecting a radiation beam onto the object, said projection means including a radiation generating means and a first optical system for projecting the radiation beam on the surface of said object in accordance with said radiation; and

detection means for detecting the radiation beam reflected from the object, said detection means including radiaion detecting means having a radiation-receiving surface for detecting the intensity distribhution of the radiation on said radiation-receiving surface, andf a second optical system for guiding at least a portion of the reflected radiation beam from the object to said radiation-receiving surface, said second optical system being so disposed as to bring said radiation-receiving surface into a substantially optically conjugated relation with a line segment of the optical axis of the first optical system along which the object is located and also into a predetermined relationship wherein the position of said radiation beam on said radiation-receiving surface changes linearly in accordance with an amount of displacement of the object along said line segment of the optical axis of said first optical system and the optical axis of said second optical system, intersecting the optical axis of said first optical system substantially at right angles.

6. Apparatus according to claim 5, wherein said radiation detecting means generates a signal corresponding to the intensity distribution of the radiation on said radiation-receiving surface and said apparatus further comprises means for detecting the position of the object along said line segment of the optical axis of said first optical system in accordance with said signal.

7. Apparatus for measuring the distance to an object comprising:

projection means for projecting a radiation beam onto the object, said projection means including a radiation generating means and a first optical system for projecting the radiation beam on the surface of said object, said first optical system having a lens component; and

detection means for detecting the radiation beam reflected from the object, said detection means including radiation detecting means having a radiation-receiving surface for detecting the intensity distribution of the radiation on said radiation-receiving surface, and a second optical system cooperating with said lens component for guiding at least a portion of the reflected radiation beam from the object to said radiation-receiving surface,

said second optical system bringing said radiation-receiving surface into a substantially optically conjugated relation with a line segment of the optical axis of said first optical system along which the object is located and also into a predetermined relationship wherein the position of said radiation beam on said radiation-receiving surface changes linearly in accordance with an amount of displacement of the object along said line segment of the optical axis of said first optical system.

8. Apparatus for measuring the distance to an object comprising:

projection means for projecting a radiation beam onto the object, said projection means including radiation generating means and a first optical system for projecting the radiation beam of the surface of said object; and

detection means for detecting the radiation beam reflected from the object, said detection means including radiation detecting means having a radiation-receiving surface for detecting the intensity distribution of the radiation on said radiation-receiving surface, and a second optical system for guiding at least a portion of the reflected radiation beam from the object to said radiation-receiving surface, and for bringing said radiation-receiving surface into a substantially optically conjugated realation with a line segment of the optical axis of said first optical system and also into predetermined relationship wherein the position of said radiation beam on said radiation-receiving surface changes linearly in accordance with an amount of displacement of the object along said line segment of the optical axis of said first optical system.