Deflection angle measuring device, optical signal switching system, information recording and replaying system, deflection angle measuring method, and optical signal switching method

• US 6,975,389 B2
• Filed: 03/18/2003
• Issued: 12/13/2005
• Est. Priority Date: 03/20/2002
• Status: Expired due to Fees

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Takahashi, Koichi
• Primary Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US10/389,913
• Publication Number:
  US 20030179366A1
• Time in Patent Office: 1,001 Days
• Field of Search: 356138-139, 356/614, 356/615, 356/622, 356/213, 356/218, 356/222, 385/17, 385/18
• US Class Current: 356/139
• CPC Class Codes: G11B 11/10543 using optical beam of radiation
• 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

Abstract

A light of measurement emitted from a semiconductor laser (1) is incident to a beam splitter formed by a prism (4). The light of measurement transmits into an incident surface (3) having a positive power so as to be emitted to a reflecting surface (5c) of measurement. A light reflected there is returned by a beam splitting surface (4a) so as to be reflected by a concave reflecting surface (6). The reflected light is returned so as to be condensed and focused on a light receiving surface (8) of sensor in a light measuring device (7). A position of a spot of light which is received is measured so as to measure the deflection angle of a rotating mirror (5). By doing this, it is possible to form a compact device even if the length of the optical path is long. As a result, it is possible to broaden the deflection angle measuring range.

Claims

1. A deflection angle measuring device for measuring a deflection angle of an optical deflecting element for deflecting a light comprising:

a light source for emitting a light toward a reflecting surface of measurement for which is provided in the optical deflecting element;

a beam splitter for changing at least a part of a light path of a reflected light which is reflected at the reflecting surface;

a concave reflecting surface which is disposed on a light path which is changed by the beam splitter;

a light measuring device for measuring the deflection angle of the light which is reflected at the concave reflecting surface and deflected by the optical deflecting element according to a light receiving position so as to face the concave reflecting surface.

2. A deflection angle measuring device according to claim 1, wherein

the beam splitter is a prism which transmits a light which is emitted from the light source;

and

the prism has a beam splitting surface for dividing a light which is reflected by the reflecting surface measurement.

3. A deflection angle measuring device according to claim 2, wherein the concave reflecting surface is disposed on an opposite end to a convex surface which is disposed on the prism.

4. A deflection angle measuring device according to claim 2, wherein, in the prism, a surface which faces the light source has a positive power.

5. A deflection angle measuring device according to claim 4 wherein, in the prism, a surface which faces the light source is a Fresnel lens surface.

6. A deflection angle measuring device according to claim 4 wherein, in the prism, a surface which faces the light measuring device has a negative power.

7. A deflection angle measuring device according to claim 6 wherein, in the prism, a surface which faces the light measuring device is a Fresnel lens surface.

8. A deflection angle measuring device according to claim 6 wherein, in the prism, a surface which faces the light measuring device is an aspherical surface.

9. A deflection angle measuring device according to claim 1 wherein the beam splitter is formed by parallel flat plates which transmit the light emitted from the light source.

10. A deflection angle measuring device according to claim 9 wherein the concave reflecting surface is disposed on an opposite end to a piano-convex lens.

11. A deflection angle measuring device according to claim 9 wherein a lens having a positive power is disposed between the parallel flat plates and the light source.

12. A deflection angle measuring device according to claim 11 the lens having a positive power is a Fresnel lens.

13. A deflection angle measuring device according to claim 9 wherein a lens having a negative power is disposed between the parallel flat plates and the light measuring device.

14. A deflection angle measuring device according to claim 13 wherein the lens having a negative power is a Fresnel lens.

15. A deflection angle measuring device according to claim 13 wherein the lens having a negative power is an aspherical lens having a negative power.

16. A deflection angle measuring device according to claim 1 wherein:

the beam splitter has a polarized beam splitting surface for transmitting or reflecting a light according to a polarization component; and

¼

wavelength plates are disposed between the reflecting surface of measurement and the polarized beam splitting surface and between the concave reflecting surface and the polarized beam splitting surface respectively.

17. A deflection angle measuring device according to claim 16 wherein:

a polarizing element for converting a light which is incident to the polarized beam splitting surface to a linear polarization is provided between the light source and the polarized beam splitting surface.

18. A deflection angle measuring device according to claim 1 wherein the light source is a semiconductor laser element.

19. A deflection angle measuring device according to claim 1 wherein:

the light source is a semiconductor laser element;

a lens having a positive power is disposed in a laser emitting mouth on the semiconductor laser element.

20. A deflection angle measuring device according to claim 19 wherein the lens having a positive power is a Fresnel lens.

21. A deflection angle measuring device according to claim 1 wherein the light measuring device is a one-dimensional position measuring light receptor.

22. A deflection angle measuring device according to claim 1 wherein the light measuring device is a two-dimensional position measuring light receptor.

23. A deflection angle measuring device according to claim 1 wherein the light measuring device is provided with a light receiving surface which is divided in 4 portions.

34. An optical signal switch system according to claim 24 wherein the deflection angle measuring device is any one of the deflection angle measuring device according to claims 1 to 23.

24. An optical signal switch system comprising:

an input cable unit which is provided with at least an input cable inside of which an optical signal is transmitted;

an output cable unit which is provided with at least an output cable which receives the optical signal which is transmitted inside the input cable and transmits thereinside;

an optical switching device which is disposed between the input cable unit and the output cable unit so as to selectively transmit the optical signal which is transmitted from at least one of the input cables to at least one cable in the output cable unit,

wherein the optical switching device comprises;

a light deflecting element which is disposed to be inclined at a predetermined deflecting angle so as to selectively change a light path of the optical signal which is transmitted in the input cable; and

a deflection angle measuring device for measuring the deflecting angle of the light deflecting element, and

the deflection angle measuring device comprises;

a light source which emits a light toward a reflecting surface of measurement which is disposed on the light deflecting element;

a concave reflecting surface for reflecting a light which is reflected at the reflecting surface of measurement; and

a light measuring device for measuring a deflection angle of at the light deflecting element according to a light receiving position where the light which is reflected at the concave reflecting surface is received.

25. An optical signal switch system according to claim 24 wherein a beam splitter is provided between the light source and the reflecting surface of measurement so as to reflect a light which is reflected at the reflecting surface of measurement and change a light path of at least a part of the reflected light toward the concave reflecting surface.

26. An optical signal switch system according to claim 25 wherein the beam splitter in the deflection angle measuring device is a prism which transmits a light emitted from the light source.

27. An optical signal switch system according to claim 26 wherein the concave reflecting surface in the deflection angle measuring device is disposed on an opposite end to a convex surface which is disposed on the prism.

28. An optical signal switch system according to claim 26 wherein, in the prism which is disposed in the deflection angle measuring device, a surface which faces the light source has a positive power.

29. An optical signal switch system according to claim 25 wherein a beam splitter in the deflection angle measuring device is formed by parallel flat plates which transmit a light emitted from the light source.

30. An optical signal switch system according to claim 29 wherein the concave reflecting surface in the deflection angle measuring device is disposed on an opposite end to a plano-convex lens.

31. An optical signal switch system according to claim 29 wherein a lens having a positive power is disposed between the parallel flat plates in the deflection angle measuring device and the light source.

32. An optical signal switch system according to claim 25 wherein the beam splitter has a polarized beam splitting surface for transmitting or reflecting a light according to a polarization component;

and

¼

wavelength plates are disposed between the reflecting surface of measurement and the polarized beam splitting surface and between the concave reflecting surface and the polarized beam splitting surface respectively.

33. An optical signal switch system according to claim 32 wherein a polarizing element for converting a light which is incident to the polarized beam splitting surface into a linear polarization is provided between the light source and the polarized beam splitting surface.

35. An optical signal switch system according to claim 24 wherein the light measuring device is a one-dimensional position measuring light receptor.

36. An optical signal switch system according to claim 24 wherein the light measuring device is a two-dimensional position measuring light receptor.

37. An optical signal switch system according to claim 24 wherein the light measuring device is provided with a light receiving surface which is divided in 4 portions.

38. An optical signal switch system according to claim 24 wherein the light deflecting element is formed by a galvano-meter mirror.

39. An optical signal switch system according to claim 24 wherein at least one of an end of the input cable in the input cable unit or an end of the output cable in the output cable unit is disposed in lattice matrix.

40. An optical signal switch system according to claim 24 wherein at least one of the input cable or the output cable is an optical fiber.

41. An information recording and replaying system comprising:

a recording medium having a recording surface which can record and/or replay an information signal by emitting a light thereto;

a light source which emits a light flux for recording and/or replaying the information signal to the recording medium;

an optical system for focusing the light flux on a recording surface on the recording medium;

a light deflecting element which is disposed in the optical system for deflecting the light flux in a surface parallel with the recording surface and has a reflecting surface of which inclination angle changes synchronously according to the deflection angle; and

a deflection angle measuring device for measuring the deflection angle of the light deflecting element,

wherein the deflection angle measuring device is provided with;

a light source for emitting a light to a reflecting surface of measurement which is disposed on the light deflecting element;

a concave reflecting surface for reflecting a light which is reflected at the reflecting surface of measurement;

a light measuring device for receiving a light which is reflected at the concave reflecting surface and measures the deflection angle at the light deflecting element.

42. An information recording and replaying system according to claim 41 wherein a beam splitter for switching at least a part of a light which is reflected at a reflecting surface to a light path which is directed to a concave reflecting surface is disposed between the light source and the reflecting surface of measurement.

43. Deflection angle measuring method for measuring a deflection angle at a light deflecting element by emitting a light to a reflecting surface of measurement which is disposed on a light deflecting element for deflecting a light by inclining a reflecting surface comprising steps of:

emitting a measurement light on a reflecting surface on the light deflecting element by transmitting a part of a measurement light through a beam splitter;

reentering a light which is reflected at the reflecting surface so as to be incident to a surface of the beam splitter and switching a light path of at least a part of the light;

reflecting the light of which light path is switched at the concave reflecting surface;

receiving a light which is reflected at the concave reflecting surface by the light measuring device; and

measuring a position for where the reflected light is received by the light measuring device so as to measure the deflection angle.

44. Optical signal switching method for selectively entering an optical signal which is emitted from at least one of a plurality of input cables to be incident to at least one of a plurality of output cables and transmitting the optical signal in the output cables comprising steps of:

specifying a position of the input cable, among a plurality of input cables, from which the optical signal is emitted and a position of the output cable which is selected;

specifying a deflection angle of a light deflecting element for reflecting a light which is emitted from the input cable of which position is specified to the selected output cable;

emitting a light for measuring the deflection angle to a reflecting surface of measurement which is disposed on the light deflecting element and reflecting the light thereat;

returning a light path of the reflected light via a concave reflecting surface and receiving the reflected light by the light measuring device;

measuring the deflection angle of the light deflecting element according to a position where the light is received;

adjusting the deflection angle of the light deflecting element so as to be a predetermined angle; and

entering the optical signal to be incident to the selected output cable such that the optical signal is selectively transmitted.

45. Optical signal switching method according to claim 44 wherein

a light for measuring the deflection angle is emitted to a reflecting surface via a beam splitter;

a light which is reflected at the reflecting surface of measurement is reflected at the concave reflecting surface via the beam splitter; and

a light transmits through the beam splitter so as to be introduced to the light measuring device.