Tilt sensing device and method for its operation

• US 6,392,223 B1
• Filed: 06/28/1999
• Issued: 05/21/2002
• Est. Priority Date: 05/21/1996
• Status: Expired due to Fees

• Current Assignee: Pharmacia AB (Pharmacia Corp.)
• Original Assignee: Pharmacia AB (Pharmacia Corp.)
• Inventors: Hjertman, Birger, Holte, Anders
• Primary Examiner(s): ALLEN, STEPHONE B
• Application Number:
  US09/180,494
• Time in Patent Office: 1,058 Days
• Field of Search: 250/231.1, 250/221, 250/222.1, 250/216, 250/239, 333/661.1, 333/661.2, 333/662.3, 333/662.4, 333/91, 735/141.9, 735/142.6
• US Class Current: 250/231.1
• CPC Class Codes: G01C 2009/066 optical
• CPC Class Codes: G01C 2009/107 spheres
• CPC Class Codes: G01C 9/10 by using rolling bodies , e.g. spheres, cylinders, mercury droplets

Abstract

A tilt sensing device and method for its operation, the device being of the type comprising (a) a housing, (b) a radiation transmitter and a radiation receiver arranged in or at the housing to form a beam path therebetween, (c) a radiation obstructing or deflecting body movable in relation to the beam path and (d) a rest surface for the body defining at least two possible rest positions for the body can move by gravity at defined tilt angles for the device and which rest positions are selected to give a detectable output difference from the radiation receiver depending on which of the rest positions is occupied by the body. The size of the movable body, expressed as the diameter of a sphere of corresponding volume, is less than 10 mm. Operation of the device includes monitoring the output from the receiver to obtain an amplitude versus time function and processing data from the function to obtain a modified signal.

Claims

1. A tilt sensing device comprising a) a housing, b) a radiation transmitter and a radiation receiver arranged in or at the housing to form a beam path therebetween, c) a radiation obstructing or deflecting body movable in relation to the beam path, d) a rest surface for the body defining at least two possible rest positions for the body relative to the beam path, between which rest positions the body can move by gravity at defined tilt angles for the device and which rest positions are selected to give a detectable output difference from the radiation receiver depending on which of the rest positions is occupied by the body, and e) at least one collimating or convergent focusing lens for direction of the beam, wherein, in at least one rest position, the rest surface is arranged to give point contact only against the body.

2. The device of claim 1, wherein the size of the movable body is less than 3 mm and exceeds 0.01 mm.

3. The device of claim 1, wherein the housing includes at least part of the rest surface.

4. The device of claim 1, wherein the housing forms part of a cavity confining at least the beam and the movable body.

5. The device of claim 4, wherein the cavity contains gas.

6. The device of claim 1, wherein the radiation comprises electromagnetic radiation with a frequency range between microwaves and ultraviolet.

7. The device of claim 1, wherein the transmitter comprises a light emitting diode and the receiver comprises a photodiode or phototransistor.

8. The device of claim 1, wherein the transmitter and receiver comprises a transceiver.

9. The device of claim 1, wherein transmitter and receiver are arranged facing substantially in the same direction.

10. The device of claim 1, wherein transmitter and receiver are oppositly arranged facing each other at a mutual distance.

11. The device of claim 1, wherein said output difference is based on an incomplete shielding mechanism in which a certain level of transmission is maintained and levels of shielding are made indicative of body position.

12. The device of claim 1, wherein the movable body has contrasting absorptive properties with respect to its surroundings.

13. The device of claim 1, wherein the body is transparent and refractive in relation to the radiation.

14. The device of claim 1, further comprising means for detectably changing the radiation frequency between transmitter and receiver.

15. The device of claim 1, wherein the body is roughly spherical.

16. The device of claim 1, wherein the body has, relative to the body size, small and numerous irregularities.

17. The device of claim 1, wherein the rest surface comprises at least one surface with continuous rest positions over which the body can freely move in response to various tilt angles.

18. The device of claim 1, wherein the rest surface comprises at least one discrete rest position arranged to maintain the body stably and wherein an activation energy is required for displacement of the body therefrom.

19. The device of claim 18, wherein the discrete rest position is arrange to provide a hysteresis in angles for displacement to and from the position respectively.

20. The device of claim 18, wherein at least two discrete rest positions are provided, without any stable position for the body therebetween.

21. The device of claim 1, wherein the rest surface provides rest positions all around the circumference of a cross-section reference plane through and parallel with the beam path.

22. The device of claim 21, wherein the circumference comprises a contour section with concave character and a contour section with inwardly protruding or convex character to prevent body occupation.

23. The device of claim 1, wherein the rest surface provides extremes for body movements lateral to the beam, the distance between which extremes is less than 5 times the body main diameter and more than 0.5 times said diameter.

24. The device of claim 1, wherein, in respect of a cross-section reference plane through and parallel with the beam path, the rest surface gives different outputs for a tilt in a direction moving the body within said plane and for a tilt direction moving the body at an angle with said plane, respectively.

25. The device of claim 1, wherein, in respect of a cross-section reference plane through and parallel with the beam path, the rest surface gives substantially the same output for tilt directions moving the body within said plane and for a tilt direction moving the body at an angle with said plane, respectively.

26. The device of claim 25, wherein the rest surface is substantially rotationally symmetrical based on rotation of said reference plane.

27. The device of claim 1, wherein the transmitter and receiver are at least partially sealed off against the rest surface or the housing.

28. The device of claim 27, wherein the sealing is made so as to only partially enclose the transmitter and receiver.

29. The device of claim 1, wherein at least one of the transmitter and the receiver is larger than the movable body.

30. The device of claim 1, wherein the rest surface is arranged to give at least two contact points.

31. The device of claim 30, wherein at least one contact point is provided by a protruder in the form of a spike, which contact point is located outside a line between two other contact points or within a circumference defined by three or more contact points and slightly lifting the body from three or more points.

32. The device of claim 1, wherein the contact points are provided at a recess in the rest surface, which recess is non-congruent with the body.

33. The device of claim 1, wherein the rest position is arranged in the beam path.

34. The device of claim 33, wherein said lens is arranged to give at least one contact point against the body.

35. A tilt sensing device comprising a) a housing, b) a radiation transmitter and a radiation receiver arranged in or at the housing to form a beam path therebetween, c) a radiation obstructing or deflecting body movable in relation to the beam path, and d) a rest surface for the body defining at least two possible rest positions for the body relative to the beam path, between which rest positions the body can move by gravity at defined tilt angles for the device and which rest positions are selected to give a detectable output difference from the radiation receiver depending on which of the rest positions is occupied by the body, wherein the body is transparent and refractive in relation to the beam radiation.

36. The device of claim 35, wherein the size of the movable body, expressed as the diameter of a sphere of corresponding volume, is less than 10 mm.

37. The device of claim 35, wherein the size of the movable body is less than 3 mm and exceeds 0.01 mm.

38. The device of claim 35, wherein the housing includes at least part of the rest surface.

39. The device of claim 35, wherein the housing forms part of a cavity confining at least the beam and the movable body.

40. The device of claim 39, wherein the cavity contains gas.

41. The device of claim 35, wherein the radiation comprises electromagnetic radiation with a frequency range between microwave and ultraviolet.

42. The device of claim 35, wherein the transmitter comprises a light emitting diode and the receiver comprises a photodiode or phototransistor.

43. The device of claim 35, wherein the transmitter and receiver comprise a transceiver.

44. The device of claim 35, wherein the beam is directed.

45. The device of claim 44, further comprising at least one lens for direction of the beam.

46. The device of claim 35, wherein the transmitter and receiver are arranged facing substantially in the same direction.

47. The device of claim 35, wherein the transmitter and receiver are oppositely arranged facing each other at a mutual distance.

48. The device of claim 35, wherein the output difference is based on an incomplete shielding mechanism in which a certain level of transmission is maintained and levels of shielding are made indicative of body position.

49. The device of claim 35, wherein the movable body has contrasting absorptive properties with respect to its surroundings.

50. The device of claim 35, further comprising means for detectably changing the radiation frequency between transmitter and receiver.

51. The device of claim 35, wherein the body is roughly spherical.

52. The device of claim 35, wherein the body has, relative to the body size, small and numerous irregularities.

53. The device of claim 35, wherein the rest surface comprises at least one surface with continuous rest positions over which the body can freely move in response to various tilt angles.

54. The device of claim 35, wherein the rest surface comprises at least one discrete rest position arranged to maintain the body stably and wherein an activation energy is required for displacement of the body therefrom.

55. The device of claim 54, wherein the discrete rest position is arranged to provide hysteresis in angles for displacement to and from the position respectively.

56. The device of claim 54, wherein at least two discrete rest positions are provided, without any stable position for the body therebetween.

57. The device of claim 35, wherein the rest surface provides rest positions all around the circumference of a cross-section reference plane through and parallel with the beam path.

58. The device of claim 57, wherein the circumference comprises a contour section with concave character and a contour section with inwardly protruding or convex character to prevent body occupation.

59. The device of claim 35, wherein the rest surface provides extremes for body movements lateral to the beam, the distance between which extremes is less than 5 times the body main diameter and more than 0.5 times the diameter.

60. The device of claim 35, wherein, in respect of a cross-section reference plane through and parallel with the beam path, the rest surface gives different outputs for a tilt in a direction moving the body within the plane and for a tilt direction moving the body at an angle with the plane, respectively.

61. The device of claim 35, wherein, in respect of a cross-section reference plane through and parallel with the beam path, the rest surface gives substantially the same output for tilt directions moving the body within the plane and for a tilt direction moving the body at an angle with the plane, respectively.

62. The device of claim 60, wherein the rest surface is substantially rotationally symmetrical based on rotation of the reference plane.

63. The device of claim 35, wherein the transmitter and receiver are at least partially sealed off against the rest surface or the housing.

64. The device of claim 63, wherein the scaling is made so as to only partially enclose the transmitter and receiver.

65. The device of claim 35, wherein at least one of the transmitter and the receiver is larger than the movable body.

66. The device of claim 35, wherein, in at least one rest position, the rest surface is arranged to give point contact only against the body.

67. The device of claim 66, wherein the rest surface is arranged to give at least two contact points.

68. The device of claim 66, wherein the contact points are provided at a recess in the rest surface, which recess is non-congruent with the body.

69. The device of claim 66, wherein the rest position is arranged in the beam path.

70. The device of claim 69, wherein a lens is arranged to give at least one contact point against the body.