Optical flex sensor

• US 4,937,444 A
• Filed: 10/05/1989
• Issued: 06/26/1990
• Est. Priority Date: 09/29/1982
• Status: Expired due to Term

• Current Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Original Assignee: VPL Research, Inc.
• Inventors: Zimmerman, Thomas G.
• Primary Examiner(s): Nelms, David C.
• Application Number:
  US07/418,919
• Time in Patent Office: 264 Days
• Field of Search: 250/226, 250/231 R, 250/551, 250/221, 250/227, 341/31, 73/293, 73/760, 73/788, 73/800, 73/862, 455/602
• US Class Current: 250/231.1
• CPC Class Codes: A61B 5/1121 Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/1126 using a particular sensing technique
• CPC Class Codes: A61B 5/6806 Gloves
• CPC Class Codes: G01B 11/16 for measuring the deformation in a solid, e.g. optical strain gauge
• CPC Class Codes: G01D 5/35345 using Amplitude variations to detect the measured quantity

Abstract

An optical flex sensor is provided and consists of a flexible tube having two ends, a reflective interior wall within the flexible tube and a light source placed within one end of the flexible tube and a photosensitive detector placed within the other end of the flexible tube to detect a combination of direct light rays and reflected rays when the flexible tube is bent.

Claims

1. An optical flex sensor which comprises:

(a) a flexible tube having two ends;

(b) a light reflective material coated on the interior wall within said flexible tube;

(c) at least one light source placed within a first end of said flexible tube; and

(d) a photosensitive detector placed within a second end of said flexible tube to detect the intensity of a light ray impinging on said photosensitive detector when said flexible tube is bent, said detector providing a signal which varies according to the continuous extent of flexing of said tube.

2. An optical flex sensor as recited in claim 1 wherein said flexible tube is made of rubber.

3. An optical flex sensor as recited in claim 2 wherein the reflective interior wall is coated with at least one reflective material.

4. An optical flex sensor as recited in claim 3 wherein said photosensitive detector includes a silicon phototransistor.

5. An optical flex sensor as recited in claim 4 wherein said light source includes at least one light emitting diode.

6. An optical flex sensor as recited in claim 5 wherein the light source and detector include optical fibers.

7. An optical flex sensor as recited in claim 4 wherein the reflective interior wall is coated with a plurality of differently colored light reflective materials on longitudinally separate areas, further including a plurality of light sources having colors corresponding to the colors of the light reflective materials.

8. The sensor according to claim 1 wherein the detector further comprises resistance means for producing a resistance which continuously varies as the flexible tube is bent, the resistance corresponding to the degree of bending of the flexible tube.

9. An optical flex sensor comprising:

a flexible tube having two ends and an interior wall, said interior wall being coated with a plurality of differently colored light reflective materials on longitudinally separate areas;

a plurality of light sources at a first end of the flexible tube having colors corresponding to the colors of the light reflective materials; and

a photosensitive detector at a second end of the flexible tube capable of detecting the light emitted from the plurality of light reflective sources.

10. An optical flex sensor as in claim 9, wherein the flexible tube is made of rubber.

11. An optical flex sensor as in claim 9, wherein the light sources and detectors include optical fibers.

12. An optical flex sensor as in claim 11, wherein the photosensitive detector includes a silicon phototransistor.

13. An optical flex sensor as in claim 11, wherein the light sources include light emitting diodes.

14. A flex sensor comprising:

a light source;

a light sensor;

a flexible conduit for communicating light from the light source to the light sensor as the conduit is bent in a selected direction, the conduit including means for decreasing the amount of light communicated from the light source to the light sensor as the conduit is bent; and

wherein the light sensor includes means for providing a signal corresponding to the continuous amount of light received by the sensor as the conduit is bent.

15. The sensor according to claim 14 wherein the conduit comprises a flexible tube.

16. The sensor according to claim 14 wherein the light sensor further comprises resistance means for producing a resistance which continuously varies as the flexible conduit is bent, the resistance corresponding to the degree of bending of the flexible conduit.

17. A method of indicating flexure comprising the steps of:

disposing a flexible conduit between a light source and a light sensor;

bending the conduit;

communicating light from the light source to the light sensor as the conduit is being bent;

decreasing the amount of light received by the light sensor as the conduit is being bent;

providing a signal corresponding to the continuous amount of light received by the light sensor; and

indicating the continuous extent of bending of the conduit with the signal.

18. The method according to claim 17 wherein the signal providing step comprises the step of providing a resistance which varies according to the amount of light received by the sensor.

19. The method according to claim 18 wherein the conduit disposing step further comprises the step of disposing a tube between the light source and the light sensor.

20. The method according to claim 19 further comprising the step of coating an interior wall of the tube with a reflective material.

21. The method according to claim 20 wherein the coating step further comprises the step of coating the interior wall of the tube with a plurality of differently colored light reflective materials on longitudinally separate area of the tube.

22. The method according to claim 21 further comprising the step of disposing a plurality of the light sources at one end of the tube, the plurality of light sources having colors corresponding to the colors of the light reflective material.