Optic system using spectral character shift for communication between optic input devices and reader devices for control systems and sensors for pressure, force, displacement, or chemical condition

• US 8,022,835 B2
• Filed: 10/24/2005
• Issued: 09/20/2011
• Est. Priority Date: 10/24/2005
• Status: Active Grant

• Current Assignee: Nathan John Coleman
• Original Assignee: Nathan John Coleman
• Inventors: Coleman, Nathan John
• Primary Examiner(s): CROSLAND, DONNIE L
• Application Number:
  US11/256,890
• Publication Number:
  US 20070090281A1
• Time in Patent Office: 2,157 Days
• Field of Search: 340/686.6
• US Class Current: 340/686.6
• CPC Class Codes: B60C 23/0423 Photo-electric, infrared or visible light means
• CPC Class Codes: B64C 13/0425 for actuating trailing or leading edge flaps, air brakes or spoilers
• CPC Class Codes: G01D 5/35303 using a reference fibre, e.g. interferometric devices

Abstract

An improved optic system for measuring and/or controlling displacement, force, pressure, position, or chemistry is disclosed. This apparatus allows for more accurate, robust, and economical communication between the transducer (or control input element) and the reader device (or control output), allows the use of a single optic fiber and/or or a gap for the communication link, and produces substantial insensitivity to attenuation due to mechanical, chemical, thermal, and radiation effects acting on the optic fiber or open space in which the signal propagates. It is also significantly immune to interference from electromagnetic radiation, since the link can be easily produced as a non-conductor which will not propagate unwanted electrical energy or lightning, and is intrinsically safe from igniting fires or explosions. It also facilitates use on rotating machinery and remote location of the transducer by the ability to transmit the signal across a large gap or air space.

Claims

1. A communication system for an optic type sensor comprising:

(a) a transducer which receives an input light signal and returns an output light signal comprising two or more distinct components at least one of which changes predictably in relation to a pressure, force, or displacement acting upon a focusing reflective and or focusing transparent element of the transducer, wherein the characteristics of at least one component of the output light signal is affected in a different manner by the pressure, force or displacement acting on the transducer than the other component or components of the output light signal;

(b) an input light signal;

(c) a single strand optic fiber which conducts the input light signal from the light source into the transducer and returns a modified light signal along the same single strand optic fiber;

(d) a light splitter located along the single strand optic fiber, between the light source and the transducer, which causes a portion of the returning output light signal to be transmitted into a separate communication channel;

(e) a reader device which receives the returning output light signal spilt off by the light splitter and decodes it into a pressure, force or displacement reading;

(f) a communication channel between the light splitter and the reader device.

2. The communication system of claim 1 wherein the communication channel between the light splitter and the reader device comprises a single strand fiber optic cable.

3. The communication system of claim 1 wherein the communication channel between the light splitter and the reader device comprises a space gap.

4. The communication system of claim 3 wherein there are two or more optic paths, one or more propagating the input or excitation light signal to the transducer and one or more propagating the output or signal light to a reader device without a light splitter.

5. The communication system of claim 3 wherein the output light signal emitted by the transducer further comprises light of two or more different wavelengths emitted at substantially the same time, and in which the ratio of energy emitted by the transducer in these different wavelengths changes predictably with pressure, force or displacement acting on the transducer.

6. The communication system of claim 3 wherein the input and output light signals are further comprised of a signal pulse and a reference pulse which are distinguished by the time of their arrival at the reader device substantially along a single path between the transducer and the reader device;

where the quantity being measured is determined by comparing the energy present in the different pulses which are affected differently by pressure, force or displacement acting upon the transducer;

where the reference pulse arrives at the reader device proximate in time with the signal pulse;

where a time gap occurs between the reference pulse and the signal pulse;

where the wavelength of the signal pulse and the wavelength of the reference pulse are not determinative of signal differentiation; and

where the signal pulse and the reference pulse travel substantially along the single path.

7. The communication system of claim 3 wherein the transducer separates input light energy into its components by wavelength and preferentially attenuates either longer or shorter wavelengths being reflected back to the reader device in a predictable manner based on the pressure, force or displacement acting upon the transducer.

8. The communication system of claim 3 wherein the input energy is used to generate light by fluorescence.

9. The communication system of claim 1 further comprising a curved reflector positioned to focus light to a point within the transducer.

10. The communication system of claim 1 further comprising a lens to focus light to a point within the transducer.

11. The communication system of claim 3 wherein the transducer is an assembly further comprising a base, a non-rigid spheroid structure with an interior reflective surface extending from said base, and a housing assembly within said spheroid assembly mounting a prism at the at rest focal center of the spheroid structure with said mounting assembly also configured to fix an optic fiber in place so as to direct light transmitted through said optic fiber into said prism and to receive light returned back through said prism.

12. The communication system of claim 3 wherein the transducer is an assembly further comprising a base, a rigid spheroid structure with an interior reflective surface, a flexible assembly connecting said base to said spheroid structure, and a housing assembly fixed in position to said base and positioned within said spheroid assembly and mounting a prism at the at rest focal center of the spheroid structure with said housing assembly also configured to fix an optic fiber in place so as to direct light transmitted through said optic fiber into said prism and to receive light returned back through said prism.

13. The communication system of claim 3 wherein the transducer is a bellow or diaphragm assembly further comprising a filter to separate signal and reference light by wavelength.

14. The communication system of claim 3 wherein the transducer is a bellow or diaphragm assembly further comprising more than one optic paths of differing length such that the light propagating along one path would be affected differently by the quantity of pressure, force or displacement, being measured than the light propagating along any other path.

15. The communication system of claim 3, further comprising:

a pneumatic tire, an optic fiber, and a port on the rim of the assembly to which the tire is substantially removably attached, where a signal light is capable of being emitted through the port.

16. The communication system of claim 3 configured to measure a physical quantity of a component of rotating machinery.

17. The communication system of claim 3 wherein the sensor is a transducer configured to detect control inputs made by a system operator and communicate said inputs to the components being operated by said system operator.

18. A communication system for a chemical sensor comprising:

(a) a transducer which receives an input light signal and emits an emitted light due to fluorescence with certain characteristics which change predictably with chemical composition acting on transducer, with at least one of the characteristics of emitted light affected in a different manner than the other characteristics by said chemical composition acting on the exterior surface of the transducer.

(b) a source of light inputted into a single strand optic fiber;

(c) a single strand optic fiber which conducts the input light signal from the light source into the transducer and returns a modified light signal along the same single strand optic fiber;

(d) a light splitter located along the single strand optic fiber, between the light source and the transducer, which causes a portion of the returning output light signal to be transmitted into a separate communication channel;

(e) a reader device which receives the returning output light signal spilt off by the light splitter and decodes it into a chemical state reading;

(f) a communication channel between the light splitter and the reader device;

(g) where a fluorescent element changes fluorescent properties with chemical exposure comprising a fluorescent signal channel;

(h) where a reference channel comprising a fluorescent elements is affected minimally from the fluorescent element, which returns light to the reader device via an optic fiber.

19. The communication system of claim 18 wherein the communication channel between the light splitter and the reader device is a single strand fiber optic cable.

20. The communication system of claim 19 wherein the communication channel between the light splitter and the reader device is a space gap between the transducer and the reader device such as to allow remote line of sight reading over a distance of the emitted signal from the transducer and/or rotation of the transducer relative to the emitter device.

21. The communication system of claim 18 wherein the transducer emits light of two or more different wavelengths at substantially the same time, and the ratio of emitted energy in these different wavelengths changes predictably with chemical condition to which the transducer is exposed to.

22. The communication system of claim 18 wherein the chemical condition being measured is pH.

23. The communication system of claim 18 wherein the chemical condition being measured is the concentration of one substance dissolved into or present in another substance.

24. The communication system of claim 18 wherein the signal light is generated by fluorescence.

25. The communication system of claim 18 wherein the transducer is comprised of one or more fluorescent elements which are strongly affected by the chemical condition being measured and one or more fluorescent elements which are less strongly affected by the chemical condition being measured.

26. The communication system of claim 18 where a chemical dye is reactive to fluorescent light;

where an affected fluorescent element responds at a known wavelength;

where an unaffected fluorescent element is substantially unaffected by the emitted light;

where the emitted light affects a second fluorescent element; and

where the intensity of the signal channel corresponding to the second fluorescent element is compared to the reference channel; and

where the transducer is made of biocompatible material.

27. The communication system of claim 18 wherein the output or signal light is propagated to the reader device along a separate optic path from the input or excitation light.

28. The communication device of claim 18 wherein the transducer further comprises a chamber with a permeable exterior membrane, with said chamber containing two or more chemical compounds, one of said compounds whose fluorescent response does not change with respect to the chemical state being measured, and one or more of said compounds whose fluorescent response measurable changes with respect to the chemical state being measured.

29. The communication device of claim 18 wherein the transducer further comprises an encapsulated fluorescent material whose fluorescent response does not significantly change when exposed to material being measured, a coating of fluorescent material whose fluorescent response measurably changes with response to the material being measured, with said coating covering and adhering said encapsulated fluorescent material to the end of said single strand optic fiber which conducts the input light signal.