Optical displacement sensor utilizing optical diffusion and reflection

• US 5,389,777 A
• Filed: 07/30/1993
• Issued: 02/14/1995
• Est. Priority Date: 10/02/1992
• Status: Expired due to Term

• Current Assignee: Philip K. Chin
• Original Assignee: Philip K. Chin
• Inventors: Chin, Philip K.
• Primary Examiner(s): Allen, Stephone B.
• Application Number:
  US08/100,488
• Time in Patent Office: 564 Days
• Field of Search: 250/221, 250/227.21, 250/229, 250/231.13, 250/214 PR, 250/561, 341/31, 341/13
• US Class Current: 250/214.0PR
• CPC Class Codes: G01D 5/30 the beams of light being detected by photocells
• CPC Class Codes: G01D 5/34 the beams of light being detected by photocells

Abstract

The invention relates to optical devices, particularly to an optical displacement transducer for detecting a light flow received by a light sensor and subsequent determination of the amount of force applied to an object within which the optical displacement transducer is mounted. The transducer utilizes a light source which is mounted within a housing having a translucent face, and a light sensor mounted in a body having a corresponding translucent face. The light flow which travels between the translucent faces is intermittently blocked by a shadow rod moving between the light source and the light sensor in response to an external force applied to the shadow rod.

Claims

1. An optical displacement transducer, comprising:

a light emitting means for emitting a light flow comprising a light emitting housing having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the light emitting housing for channelling the light flow from the light emitting housing;

a light receiving means for receiving the light flow mounted opposite the light emitting housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for retaining a light sensor, said light receiving body being provided with a translucent face in a portion thereof which is oriented in a substantially parallel relationship to the light emitting housing translucent face; and

a light blocking means for intermittently blocking the light flow between the light source and the light sensor and for varying the amount of light reaching the light sensor, said light blocking means comprising a flexible shadow rod having a first portion which moves between said light emitting housing and said light receiving body, and a second portion which is oriented at an angle to the first portion.

2. The device of claim 1, further comprising a shadow rod sleeve for enclosing at least a middle portion of said shadow rod to thereby guide movement of the shadow rod first portion in the desired direction.

3. The device of claim 1, further comprising means for restricting relative movement between the flexible shadow rod and the sleeve.

4. The device of claim 3, wherein said restricting means comprises a collar secured to the flexible rod adjacent its first portion, said collar having a surface against which the sleeve abuts.

5. The device of claim 1, wherein said flexible shadow rod is made from a resilient light impermeable material.

6. An optical displacement transducer, comprising,

a light emitting means for emitting a light flow, comprising a housing having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the light emitting housing for channelling the light flow from the light emitting housing;

a light receiving means for receiving the light flow mounted opposite the housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for retaining a light sensor, said light receiving body being provided with a translucent face in a portion thereof which is oriented in substantially parallel relationship to the light emitting housing translucent face; and

a flexible light blocking means for intermittently blocking the light flow between the light source and the light sensor and for varying the amount of light reaching the light sensor, said light blocking means comprising a flexible, resilient shadow rod having a first portion which moves between said light emitting housing and said light receiving body, and a second portion which is oriented at an angle to the first portion, said light emitting means further comprising a sleeve for enclosing at least a middle portion of said shadow rod to thereby guide movement of the shadow rod first portion in the desired direction.

7. The device of claim 6, further comprising means for preventing relative movement between the shadow rod and the sleeve, said restricting means comprising a collar fixedly attached to the shadow rod adjacent its first portion, said collar forming an abutting surface for the sleeve.

8. An optical displacement transducer, comprising:

a light emitting means for emitting a light flow, comprising a light emitting housing, having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the light emitting housing for channelling the light flow from the light emitting housing;

a light receiving means for receiving the light flow mounted opposite the light emitting housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for retaining a light sensor, said light receiving body being provided with a translucent face in a portion thereof which is oriented in a substantially parallel relationship to the light emitting housing translucent face;

a light blocking means for intermittently blocking the light flow mounted between the light emitting housing and the light receiving body, said light blocking means comprising a light impermeable member movable in a linear direction; and

means for channelling the light flow at an angle in relationship to a longitudinal axis of the light emitting housing.

9. The device of claim 8, wherein said means for channeling the light flow comprises a curved end wall formed at one end of the light emitting housing adjacent said translucent face, said curved wall forcing the light flow to change its substantially linear travel path to a curved flow path.

10. The device of claim 8, wherein said light blocking means comprises a light impermeable shadow rod having an opening made therein, said opening allowing the light flow to travel from the light emitting housing to the light receiving body when said opening is aligned with translucent faces of the light emitting housing and the light receiving body, while at least a portion of the light flow is blocked by the shadow rod.

11. The device of claim 8, wherein said means for channelling the light flow comprises a curved wall formed in one end of said light receiving body adjacent said translucent face, said curved wall forcing the light flow to change its substantially linear travel path to a curved flow path.

12. The device of claim 8, wherein said means for channeling the light flow comprises a curved wall formed in one end of said light receiving body adjacent its translucent face and a curved wall formed in one end of said light emitting housing adjacent its translucent face, said curved walls forcing the light flow to change its substantially linear travel path to a curved flow path.

13. The device of claim 8, wherein said means for channeling the light flow comprises an angular end wall formed in the light emitting housing adjacent said translucent face, said end wall being oriented at an angle to a longitudinal axis of the light emitting housing.

14. The device of claim 8, wherein said means for channeling the light flow comprises an angular end wall formed in said light receiving body adjacent said translucent face, said angular end wall being oriented at an angle to a longitudinal axis of the light receiving body.

15. The device of claim 8, wherein said means for channelling the light comprises an angular wall formed in an end of said light emitting housing adjacent said translucent face and an angular end wall formed in an end of said light receiving body adjacent the translucent face of the light receiving body, said angular end walls forcing the light flow to change its travel path when passing along said angular end walls.

16. The device of claim 8, wherein said means for channelling the light flow comprises a quarter-spherical wall formed in that portion of the light emitting housing adjacent the translucent face, said quarter-spherical wall causing the light flow to change its travel path to a curved flow when passing along said quarter-spherical wall.

17. The device of claim 8, wherein said means for channeling the light flow comprises a quarter-spherically-shaped wall formed in that end of the light receiving body adjacent the translucent face, said quarter-spherically-shaped wall causing the light flow to change its travel path when passing along said quarter-spherically-shaped wall.

18. The device of claim 8, wherein said means for channeling the light flow comprises a quarter-spherically-shaped end wall formed in that portion of the light emitting housing adjacent said translucent face and a quarter-spherically-shaped end wall made in that portion of the light receiving body adjacent the translucent face of the light receiving body, said end walls facilitating channeling of the light in the desired direction.

19. The device of claim 8, wherein said light impermeable member comprises a spiral disk having a spiral window made therein for allowing at least a portion of the light flow to pass the light receiving body.

20. The device of claim 19, wherein said spiral disk is provided with means for receiving a torque from an external source of rotation, said torque receiving means comprising a rod which extends at a right angle to a normal axis of the disk and which is fixedly attached to the disk.

21. The device of claim 18, wherein said light emitting housing and said light receiving body each have a semi-circular cross section.

22. The device of claim 18, wherein said light emitting housing and said light receiving body each have at least a portion which is substantially light permeable to facilitate a total internal reflection.

23. The device of claim 8, further comprising a light impermeable cover sized and shaped to cover at least a portion of a non-translucent exterior surface of the housing.

24. The device of claim 8, further comprising a light impermeable cover for covering at least a portion of a non-translucent exterior surface of the light receiving body.

25. The device of claim 8, further comprising a pair of covers, each cover being sized and shaped to cover at least a portion of a non-translucent exterior surface of the corresponding light receiving body and of the light emitting housing.

26. The device of claim 8, wherein said means for channeling the light flow comprises a curved wall formed in a portion of the light emitting housing adjacent the translucent face of the light emitting housing, and a curved wall formed at an end of the light receiving body adjacent the translucent face of the light receiving body, said light emitting housing and light receiving body being mounted in such a manner that their respective translucent faces are misaligned in relationship to each other, so as to produce a generally Z-shaped light flow traveling from the light source to the light sensor.

27. An optical displacement transducer, comprising:

a light emitting means for emitting a light flow, comprising a light emitting housing having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the housing for channelling the light flow from the housing, said light emitting housing having an elongated body having a generally rectangular solid shape and having a curved end wall adjacent said translucent face for causing at least a portion of the light flow to turn at an obtuse angle in relationship to a longitudinal axis of the light emitting housing and thereby facilitate channeling of the light exiting the light emitting housing;

a light receiving means for receiving the light flow mounted opposite said light emitting housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for retaining a light sensor, said light receiving body being provided with a translucent face in a portion thereof which is located in a substantially parallel relationship to the translucent face of the light emitting housing; and

a light blocking means for intermittently blocking the light flow and varying the amount of light reaching the light sensor.

28. The device of claim 27, wherein said light blocking means comprises an elongated light impermeable body having a window made therein for allowing at least a portion of light to travel from the light source to the light sensor.

29. The device of claim 27, wherein said light receiving body comprises an elongated, generally rectangular solid body having a curved end wall, said end wall causing at least a portion of the light flow to turn at an angle when entering the light receiving body and thereby facilitate channeling of the light flow in the desired direction.

30. An optical displacement transducer, comprising:

a light emitting means for emitting a light flow, comprising a light emitting housing having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the housing for channelling the light flow from the housing, said light emitting housing having an elongated body having a generally rectangular solid shape and having an end wall extending at an angle in relationship to a longitudinal axis of the housing adjacent said translucent face for causing the light flow to turn at an angle in relationship to the longitudinal axis of the light emitting housing and thereby facilitate channeling of the light leaving the light emitting housing;

a light receiving means for receiving the light flow mounted opposite the housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for retaining a light sensor, said light receiving body being provided with a translucent face in a portion thereof which is located in a substantially parallel relationship to the translucent face of the light emitting housing; and

a light blocking means for intermittently blocking the light flow and varying the amount of light reaching the light sensor.

31. The device of claim 30, wherein said light receiving body comprises an elongated, generally rectangular solid body having an end wall extending at an angle in relationship to a longitudinal axis of the body, said end wall causing at least a portion of the light flow to turn at an angle when entering the light receiving body to facilitate channeling of the light flow in the desired direction.

32. An optical displacement transducer, comprising:

a light emitting means for emitting a light flow, comprising a light emitting housing having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the housing for channelling the light flow from the housing, said light emitting housing having an elongated body having a generally rectangular solid shape and having a quarter-spherical end wall adjacent said translucent face for causing the light flow to curve its travel path when passing along said end wall;

a light receiving means for receiving the light flow mounted opposite the housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for retaining a light sensor, said light receiving body being provided with a translucent face in that portion thereof which is located in a substantially parallel relationship to the translucent face of the light emitting housing; and

a light blocking means mounted for rotational movement between the light emitting housing and the light receiving body in a normal path of the light flow to intermittently block the light flow and vary the amount of light reaching the light sensor, said light blocking means comprising a light impermeable spiral disk having a spiral window for channelling the light flow to the light sensor, said spiral disk being provided with means for receiving a torque from an external source of rotation, said torque receiving means comprising a rod fixedly attached to the disk and extending at a right angle to a normal axis of the disk.

33. An optical displacement transducer, comprising:

a light emitting means for emitting a light flow, comprising a light emitting housing having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the housing for channelling the light flow from the housing, said light emitting housing having an elongated, rectangular solid shape and having a quarter-spherical end wall adjacent to the translucent face for causing the light flow to curve its travel path when passing along said end wall and thereby facilitate channeling of the light leaving the light emitting housing;

a light receiving means for receiving the light flow mounted opposite said housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for retaining a light sensor, said light receiving body being provided with a translucent face in a portion thereof which is located in substantially parallel relationship to the translucent face of the light emitting housing; and

a light blocking means for intermittently blocking the light flow and varying the amount of light reaching the light sensor, said light blocking means comprising a light impermeable body having a window made therein for permitting at least a portion of the light flow to pass therethrough.

34. The device of claim 33, wherein the non translucent surface of said light emitting housing and said light receiving body is transparent to facilitate total internal reflection.

35. An optical displacement transducer, comprising:

a light emitting means for emitting a light flow, comprising a light emitting housing having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the housing for channelling the light flow from the housing, said light emitting housing having an elongated, generally rectangular solid shape and having a quarter-spherical end wall adjacent said translucent face for causing the light flow to change its travel path when passing along said end wall and thereby facilitate channeling of the light leaving the light emitting housing;

a light receiving means for receiving the light flow mounted opposite the housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for housing a light sensor, said light receiving body being provided with a translucent face in a portion thereof which is located in substantially parallel relationship to the translucent face of the light emitting housing, said light receiving body having an elongated, generally rectangular solid shape and a quarter-spherical end wall adjacent said translucent face of the body for causing the light flow to change its travel path when passing along said end wall of the body, thereby facilitating channelling of the light flow entering said light receiving body; and

a light blocking means for intermittently blocking the light flow and varying the amount of light reaching the light sensor, said light blocking means comprising a light impermeable body mounted for linear movement between the translucent faces of said light emitting housing an said light receiving body.

36. The device of claim 35, further comprising a pair of light impermeable covers, each cover being sized and shaped for covering at least a portion of the non-reflective surface of the corresponding light emitting housing and the light receiving body.

37. An optical displacement transducer, comprising:

a light emitting means for emitting a light flow comprising a light emitting housing having an internal chamber formed therein, a light source positioned inside the chamber, and a translucent face formed in a portion of the light emitting housing for channelling the light flow from the housing, said housing having a curved end wall for channelling the light at an angle in relationship to a longitudinal axis of the light emitting housing;

a light receiving means for receiving the light flow mounted opposite the light emitting housing, said light receiving means comprising a light receiving body having an internal chamber formed therein for retaining a light sensor, said light receiving body being provided with a translucent face in a portion thereof which is located in a substantially parallel relationship to the light emitting housing translucent face, said light receiving body having a curved wall adjacent said translucent face of the light receiving body, said translucent faces of the light emitting housing and said light receiving body being misaligned, so as to produce a generally Z-shaped light flow from the light source to the light sensor; and

a light blocking means for intermittently blocking the light flow and varying the amount of light reaching the light sensor, said light blocking means comprising a light impermeable body having a window made therein for allowing at least a part of the light flow to travel to the light sensor.

38. An optical displacement transducer, comprising:

a light source for emitting a light flow;

a light reflective and diffusive surface for receiving and re-directing the light flow away from the surface;

a light receiving and diffusive surface for receiving the light flow and re-directing the light flow away from the light receiving surface;

a light sensor for receiving the light flow reflected by the light receiving and diffusive surface; and

a light blocking means for intermittently blocking the light flow and varying the amount of light reaching the light sensor.

39. The device of claim 38, wherein said light reflective surfaces are positioned at an angle in relationship to each other.

41. The device of claim 38, wherein said light blocking means is a light impermeable body moving in a linear direction between said reflective surfaces.

40. An optical displacement transducer, comprising:

a light source for emitting a light flow;

a light reflective surface for receiving and redirecting the light flow away from the surface;

a light receiving surface for receiving the light flow and re-directing the light flow away from the light receiving surface, wherein said reflective surfaces further comprise a light diffusive means;

a light sensor for receiving the light flow reflected by the light receiving surface; and

a light blocking means for intermittently blocking the light flow and varying the amount of light reaching the light sensor.

42. A tactile sensing device, comprising:

a rigid frame;

a flexible, resilient capsule carried by said frame, said capsule forming a fluid-tight enclosure with said rigid frame; and

an optical displacement transducer mounted within said enclosure for detecting the direction and amount of force applied to said capsule.

43. The device of claim 42, wherein said enclosure defines and interior chamber, and wherein said optical displacement transducer is mounted within said chamber.

44. The device of claim 42, wherein said rigid frame carries a means for supporting the optical displacement transducer within said enclosure.

45. The device of claim 42, wherein said optical displacement transducer comprises a light emitting means for emitting a light flow, a light receiving means for receiving the light flow mounted opposite the light emitting means, and a light blocking means for intermittently blocking the light flow and varying the amount of light reaching the light receiving means.

46. The device of claim 45, wherein said light emitting means comprises a light source and the light receiving means comprises a light sensor.

47. The device of claim 42, wherein said rigid frame forms a generally cup-shaped chamber, and wherein a spring loaded piston is mounted within said chamber, said piston moving in response to a change in pressure within said enclosure.

48. The device of claim 42, wherein one end of said light blocking means engages an interior surface of said capsule, such that application of force on an exterior surface of the capsule causes movement of the light blocking means and change in the amount of light flow reaching the light sensor.

49. The device of claim 43, wherein said rigid frame carries a means for supporting the optical displacement transducer within the interior chamber, said supporting means comprising a pair of spaced-apart longitudinal plates on which said optical displacement transducer is mounted, at least one flexible resilient layer mounted between said supporting plates and the interior surface of said capsule.

50. The device of claim 49, wherein said optical displacement transducer comprises a light emitting means for emitting a light flow, a light receiving means for receiving the light flow mounted opposite said light emitting means, and a light blocking means for intermittently blocking the light flow and thereby varying the amount of light reaching the light receiving means.

51. The device of claim 50, wherein said at least one flexible resilient layer is provided with an opening through which at least a portion of said light blocking means extends and contacts an interior surface of the capsule, such that application of force on an exterior surface of the capsule causes the light blocking means to move an block at least a portion of the light flow travelling towards said light receiving means.