Deflection angle detecting device

• US 7,151,596 B2
• Filed: 07/01/2003
• Issued: 12/19/2006
• Est. Priority Date: 07/05/2002
• Status: Expired due to Fees

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Takahashi, Junko, Takahashi, Koichi
• Primary Examiner(s): Lauchman, Layla G.
• Assistant Examiner(s): VALENTIN, JUAN D
• Application Number:
  US10/609,635
• Publication Number:
  US 20040027561A1
• Time in Patent Office: 1,267 Days
• Field of Search: None
• US Class Current: 356/138
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 6/359 of the position of the moving element itself during switching, i.e. without monitoring the switched beams
• CPC Class Codes: G11B 11/10532 Heads
• CPC Class Codes: G11B 11/10576 with provision for moving the transducers for maintaining alignment or spacing relative to the carrier
• CPC Class Codes: G11B 7/08564 using galvanomirrors
• CPC Class Codes: G11B 7/08576 Swinging-arm positioners
• CPC Class Codes: G11B 7/1356 Double or multiple prisms, i.e. having two or more prisms in cooperation
• CPC Class Codes: G11B 7/1359 Single prisms
• CPC Class Codes: G11B 7/1362 Mirrors
• CPC Class Codes: G11B 7/13925 active, e.g. controlled by electrical or mechanical means

Abstract

A deflection angle detecting device includes a light source, a path switching plane switching the optical path of part of light radiated from the light source, a detecting reflection surface placed on the optical path switched by the path switching plane and provided to the light-deflecting element, and a photodetector receiving light reflected by the detecting reflection surface to detect the deflection angle of the light-deflecting element in accordance with the position where the light is received. In this case, a transmission surface with positive power is interposed between the detecting reflection surface and the photodetector.

Claims

1. A deflection angle detecting device for detecting a deflection angle of a reflection surface for detection disposed in a path of rays, the deflection angle detecting device comprising:

a light source for irradiating the reflection surface for detection with a beam of rays;

an optical element comprising a curved reflection surface with positive power arranged to be decentered from a center axis of the beam of rays as reflected from the reflection surface for detection; and

a photodetector having a light-receiving surface, for detecting the deflection angle of the reflection surface for detection in accordance with a position where the beam of rays reflected from the optical element is received on the light-receiving surface.

2. A deflection angle detecting device according to claim 1, wherein the detecting reflection surface is decentered with respect to the optical axis of the light radiated form the light source.

3. A deflection angle detecting device according to claim 1, wherein a path switching element switching at least one part of the light radiated from the light source is placed on the optical axis.

4. A deflection angle detecting device according to claim 1, wherein an optical element with positive power is interposed between the light source and the detecting reflection surface.

5. A deflection angle detecting device according to claim 1, wherein an optical element with positive power is interposed between the detecting reflection surface and the photodetector.

6. A deflection angle detecting device according to claim 4 or 5, wherein the optical element with positive power is provided with a rotational symmetrical surface.

7. A deflection angle detecting device according to claim 4 or 5, wherein the optical element with positive power includes a Fresnel lens surface.

8. A deflection angle detecting device according to claim 1, wherein the detecting reflection surface is a front surface mirror reflection surface.

9. A deflection angle detecting device according to claim 1, wherein the detecting reflection surface is a back surface mirror reflection surface configured of a medium with a refractive index of 1 or more.

10. A deflection angle detecting device according to claim 1, wherein the detecting reflection surface has rotational symmetrical optical power.

11. A deflection angle detecting device according to claim 1, wherein the detecting reflection surface has irrotational symmetrical optical power.

12. A deflection angle detecting device according to claim 1, wherein optical elements with positive powers are interposed in optical paths between the light source and the detecting reflection surface and between the detecting reflection surface and the photodetector, at least one for each optical path.

13. A deflection angle detecting device according to claim 1, wherein an optical element with positive power including a common member is interposed between the light source and the detecting reflection surface and between the detecting reflection surface and the photodetector.

14. A deflection angle detecting device according to claim 13, wherein the detecting reflection surface is provided on a back surface of the optical element with positive power including the common member.

15. A deflection angle detecting device according to claim 12, wherein at least one optical surface of one of the optical elements is configured into an irrotational symmetrical profile.

16. A deflection angle detecting device according to claim 12, wherein at least one optical surface of one of the optical elements has a function of reflecting light.

17. A deflection angle detecting device according to claim 16, wherein the optical surface having the function of reflecting light of one of the optical elements combines a function of reflecting light with a function transmitting light.

18. A deflection angle detecting device according to claim 1, wherein two sets of light-deflecting elements and detecting reflection surfaces are provided and a light beam radiated from the light source is split so that reflection angles of a plurality of light-deflecting elements provided with the detecting reflection surfaces are detected.

19. A deflection angle detecting device according to claim 1, wherein the detecting reflection surface has a reflection surface position detecting means outside an effective diameter.

30. A deflection angle detecting device according to claim 1 or 20, wherein an incident-light condensing optical element with positive power is interposed between the light source and the reflection surface for detection.

31. A deflection angle detecting device according to claim 30, wherein each of optical working surfaces of the incident-light condensing optical element is configured as a rotational symmetrical surface.

32. A deflection angle detecting device according to claim 30, wherein the incident-light condensing optical element is constructed integrally with the reflected-light condensing optical element.

33. A deflection angle detecting device according to claim 1 or 20, wherein the photodetector comprises a one-dimensional position sensor detector.

34. A deflection angle detecting device according to claim 1 or 20, wherein the photodetector comprises a two-dimensional position sensor detector.

35. A deflection angle detecting device according to claim 1 or 20, wherein the photodetector has a four-segmented light-receiving surface.

20. A deflection angle detecting device for detecting a deflection angle of a reflection surface for detection, the deflection angle detecting device comprising:

a light source for radiating a beam of rays;

a light-deflecting element having the reflection surface for detection, inclined by a preset angle with respect to a center axis of the beam of rays radiated from the light source;

an optical element comprising a curved reflection surface with positive power arranged to be decentered from a center axis of the beam of rays as reflected from the reflection surface for detection; and

a photodetector having a light-receiving surface, for detecting the deflection angle of the reflection surface for detection in accordance with a position where the beam of rays reflected from the optical element is received on the light-receiving surface.

21. A deflection angle detecting device according to claim 20, satisfying the following condition:

100°

<

θ

<

70°

where θ

is an angle of incidence of a ray traveling along the center axis of the beam of rays radiated from the light source on the reflection surface for detection.

22. A deflection angle detecting device according to claim 21, wherein at least one of optical working surfaces of the optical element has a rotationally asymmetric surface.

23. A deflection angle detecting device according to claim 20, wherein when a ray passing through a center of a position of the photodetector where the light is received, from a center of the light source, is called an axial chief ray, the reflection surface with positive power of the reflected-light condensing optical element is inclined and placed so that the axial chief ray reflected by the detecting reflection surface is reflected back toward the light source.

24. A deflection angle detecting device according to claim 22, wherein the curved reflection surface with positive power of the optical element is configured as a rotationally asymmetric surface.

25. A deflection angle detecting device according to claim 22, satisfying the following condition:

20°

<

α

<

110°

where α

is an angle made by an axial chief ray incident on the curved reflection surface with positive power of the optical element with an axial chief ray reflected by the curved reflection surface with positive power.

26. A deflection angle detecting device according to claim 20, wherein the photodetector is placed close to the light source, with a light-receiving surface directed toward an exit side of the light source.

27. A deflection angle detecting device according to claim 20, wherein each of two of optical working surfaces of the reflected-light condensing optical element is configured as a reflection surface.

28. A deflection angle detecting device according to claim 20, wherein each of at least three of optical working surfaces of the reflected-light condensing optical element is configured as a reflection surface.

29. A deflection angle detecting device according to claim 20, wherein an entrance surface and a reflection surface of the reflected-light condensing optical element are configured as a common surface.

36. An optical signal switching system for performing switching among a plurality of light-transmitting paths so that a path of an optical signal, which is conveyed through one of the light-transmitting paths, is switched to another path, the optical signal switching system comprising:

at least one light-deflecting element for switching the path of the optical signal;

a reflection surface for detection provided integrally with the light-deflecting element for detecting a deflection angle of the light-deflecting element;

a deflection angle detecting device comprising;

a light source for irradiating the reflection surface for detection with a beam of rays;

an optical element comprising a curved reflection surface with positive power arranged to be decentered from a center axis of the beam of rays as reflected from the reflection surface for detection; and

a photodetector having a light-receiving surface, for detecting a deflection angle of the reflection surface for detection in accordance with a position where the beam of rays reflected from the optical element is received on the light-receiving surface; and

a deflection angle control unit for controlling the deflection angle of the light-deflecting element through the deflection angle of the reflection surface for detection detected by the deflection angle detecting device.

37. An information recording and presenting system for recording, presenting or both recording and presenting information signals by irradiating a recording surface of a recording medium with light, the information recording and presenting system comprising:

a light source for radiating a beam of rays;

an optical system that images the beam of rays on the recording medium;

a light-deflecting element arranged in the optical system and having a reflection surface for detection constructed and arranged to change an inclination angle thereof in accordance with a deflection angle where the beam of rays is deflected in a plane parallel with the recording surface; and

a deflection angle detecting device comprising;

another light source for irradiating the reflection surface for detection with a beam of rays;

an optical element comprising a curved reflection surface with positive power arranged to be decentered from a center axis of the beam of rays radiated from the another light source as reflected from the reflection surface for detection; and

a photodetector having a light-receiving surface, for detecting a deflection angle of the reflection surface for detection in accordance with a position where the beam of rays reflected from the optical element is received on the light-receiving surface.

38. A light-deflecting system using light an angle of which is detected, the light-deflecting system comprising:

a light-deflecting element having a reflection surface for detection; and

a deflection angle detecting device comprising;

a light source for irradiating the reflection surface for detection with a beam of rays;

an optical element comprising a curved reflection surface with positive power arranged to be decentered from a center axis of the beam of rays radiated from the light source as reflected from the reflection surface for detection; and

a photodetector having a light-receiving surface, for detecting a deflection angle of the reflection surface for detection in accordance with a position where the beam of rays reflected from the optical element is received on the light-receiving surface.