Apparatus for making high-sensitivity measurements of various parameters, and sensors particularly useful in such apparatus

• US 20060087325A1
• Filed: 02/12/2004
• Published: 04/27/2006
• Est. Priority Date: 02/13/2003
• Status: Active Grant

• Current Assignee: Nexense, Ltd.
• Original Assignee: Nexense, Ltd.
• Inventors: Ravitch, Vladimir, Ariav, Arie
• Granted Patent: US 7,533,571 B2
• Time in Patent Office: Days
• US Class Current: 324/637
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/02233 Occluders specially adapted therefor tourniquets A61B17/132
• CPC Class Codes: A61B 5/02444 Details of sensor A61B5/02427 takes precedence
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/6887 mounted on external non-worn devices, e.g. non-medical devices
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 2291/048 Transmission, i.e. analysed material between transmitter and receiver
• CPC Class Codes: G01N 2291/102 one emitter, one receiver
• CPC Class Codes: G01N 29/024 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G01N 29/42 by frequency filtering or by tuning to resonant frequency
• CPC Class Codes: G01N 33/44 Resins; Plastics; Rubber; Leather

Abstract

A sensor for sensing a predetermined parameter having a known relationship with respect to the transit time of an energy wave through a medium, includes a body of soft elastomeric material having high transmissivity and low attenuation properties with respect to the energy waves; and a transmitter and receiver carried by the body in spaced relation to each other such that the energy waves received by the receiver are those transmitted by the transmitter after having traversed at least a portion of the body of soft elastomeric material. The transit time of the energy wave through the elastomeric body is measured to produce a measurement of the predetermined parameter. In the described preferred embodiments, the energy wave is a sonic wave, such that the body of soft elastomeric material serves as an acoustical channel between the transmitter and receiver.

Claims

1. Apparatus for measuring a predetermined parameter having a known or determinable relationship with respect to the transit time of an energy wave through a medium, comprising:

a sensor for sensing said predetermined parameter, said sensor including a transmitter for transmitting energy waves through said medium and a receiver for receiving said energy waves transmitted by said transmitter;

and a data processor for measuring the transit time, or changes in the transit time, of energy waves from said transmitter to said receiver to thereby produce a measurement of said predetermined parameter;

characterized in that said sensor includes a body of soft elastomeric material having high transmissivity and low attenuation properties with respect to said energy waves, said transmitter and receiver being spaced from each other by said body of soft elastomeric material such that said parameter, when sensed by said sensor, produces a displacement of said transmitter relative to said receiver, whereby measuring the transit time, or changes in the transit time, of said energy waves from said transmitter to said receiver provides a measurement of the displacement of the transmitter relative to the receiver, and thereby of said predetermined parameter.

2. The apparatus according to claim 1, wherein said elastomeric material is a silicone elastomer.

3. The apparatus according to claim 1, wherein said elastomeric material has a Shore A hardness of 5-60.

4. The apparatus according to claim 1, wherein said elastomeric material has a Shore A hardness of 7-20.

5. The apparatus according to claim 1, wherein said energy wave is a sonic wave.

6. The apparatus according to claim 1, wherein said transmitter and receiver are embedded in said body of elastomeric material.

11. The apparatus according to claim 1, wherein the apparatus includes two of said sensors mounted on a common support with one of their ends facing and aligned with each other, and their opposite ends fixed to said support;

said facing ends of the sensors being fixed to a member located between them and displaceable by said predetermined parameter towards one sensor and away from the other sensor, such that the displacement of said displaceable member in either direction compresses the elastomeric body of one sensor and expands the elastomeric body of the other sensor, thereby substantially eliminating temperature and other transient influences, while enhancing the measurement of said predetermined parameter.

53. Apparatus according to claim 1, wherein said apparatus is in the form of a hand-held portable electrical device comprising a housing carrying said sensor for enabling the device also to be used for measuring said predetermined parameter.

55. The apparatus according to claim 53, wherein said hand-held device is a cellular telephone handset or portable digital assistant.

59. Apparatus according to claim 11, wherein said data processor includes:

a single measuring channel having an input from one sensor and an output to a CPU;

and a phase-locked loop having an input from the other sensor, and an output providing clock pulses to said single measuring channel and to said CPU.

60. A system for generating a predetermined frequency, comprising:

first apparatus according to claim 1 including a first body of soft elastomeric material defining a first acoustical channel of a first effective length and having a first coefficient of linear expansion in response to temperature;

a second apparatus according to claim 1 including a second body of soft elastomeric material defining a second acoustical channel of a second effective length and having a second coefficient of linear expansion in response to temperature different from said first coefficient of linear expansion;

a first electrical feedback circuit from said first apparatus for controlling the frequency thereof;

a second electrical feedback circuit from said second apparatus for controlling the frequency thereof;

a phase detector with a low pass filter receiving the outputs of said first and second electrical feedback circuits;

and a control device controlling said first and second bodies of soft elastomeric material in response to the output of said phase detector to cause both bodies of soft elastomeric material to change their effective lengths such as to equalize the frequencies of both acoustical channels.

7-10. -10. (canceled)

12-27. -27. (canceled)

28. A sensor for sensing a predetermined parameter having a known or determinable relationship with respect to the transit time of an energy wave through a medium, comprising:

a body of soft elastomeric material having high transmissivity and low attenuation properties with respect to said energy waves;

and a transmitter and receiver carried by said body in spaced relation to each other such that the energy waves received by said receiver are those transmitted by said transmitter after having traversed at least a portion of said body of soft elastomeric material.

29. The sensor according to claim 28, wherein said elastomeric material is a silicone elastomer.

30. The sensor according to claim 28, wherein said elastomeric material has a Shore A hardness of 5-40.

31. The sensor according to claim 28, wherein said elastomeric material has a Shore A hardness of 7-20.

32. The sensor according to claim 28, wherein said energy wave is a sonic wave.

33. The sensor according to claim 28, wherein said transmitter and receiver are embedded in said body of elastomeric material.

37. The sensor according to claim 28, wherein said body of elastomeric material includes an array of said transmitters and receivers for use as a keyboard or pressure-distribution sensor.

38. The sensor according to claim 28, wherein said body of elastomeric material is of annular shape for receiving a finger, wrist or arm of a person.

39. The sensor according to claim 28, wherein said sensor also includes a weight which acts as an inertia member effective to make the sensor sensitive to the rate of change of the spacing between said transmitter and receiver.

40. The sensor according to claim 39, wherein said weight is carried by a pivotably mounted arm.

42. The sensor according to claim 28, wherein said body of soft elastomeric material is in the form of a narrow strip such as to define a narrow transmission channel between said transmitter and receiver.

44. The sensor according to claim 42, wherein said energy wave is a sonic wave and said narrow transmission channel is a narrow acoustical channel.

45. The sensor according to claim 44, wherein said sensor further includes a damper material having high sonic-wave attenuation properties at the opposite ends of said strip of soft elastomeric material, said damper material being effective to absorb sonic waves except those in said narrow acoustical channel.

34-36. -36. (canceled)

41. (canceled)

43. (canceled)

46-52. -52. (canceled)

54. (canceled)

57-58. -58. (canceled)

61. A system for generating a predetermined frequency, comprising:

a first acoustical channel having a transmitter and a receiver controlling the transmitter to transmit an integer number of sonic waves to the receiver, said first acoustical channel having a first effective length and a first coefficient of linear expansion in response to temperature;

a second acoustical channel having a transmitter and a receiver controlling the transmitter to transmit an integer number of sonic waves to the receiver, said second acoustical channel having a second effective length and a second coefficient of linear expansion in response to temperature;

a first electrical feedback circuit from said first acoustical channel to control the frequency thereof

a second electrical feedback circuit from said second acoustical channel to control the frequency thereof;

a phase detector receiving the outputs of said first and second electrical feedback circuits;

and a control device controlling said first and second acoustical channels in response to the output of said phase detector to equalize the frequencies of the two acoustical channels.

62. The system according to claim 61, wherein said phase detector has a low-pass filter.

63. The system according to claim 61, wherein each of said acoustical channels includes a body of soft elastomeric material having high sonic-wave transmissivity and low sonic-wave attenuation.