Tactile sensor employing a light conducting element and a resiliently deformable sheet

• US 4,668,861 A
• Filed: 12/12/1984
• Issued: 05/26/1987
• Est. Priority Date: 12/12/1984
• Status: Expired due to Fees

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: White, Richard M.
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Allen, S.
• Application Number:
  US06/680,759
• Time in Patent Office: 895 Days
• Field of Search: 250/227, 340/347 P, 340/780, 340/365 P, 340/407, 340/825.19, 901/46, 901/47, 901/33, 350/96.23
• US Class Current: 250/227.21
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A tactile sensing device for use in robotics and medical prosthetics includes a transparent sheet-like element and a second resilient sheet-like element positioned adjacent the first transparent element. A light detection and imaging means is positioned to observe the interface between the two elements. A light source is provided to illuminate the interior of one of the two elements. Any object pressing against the resilient element deforms the same into contact with the transparent element. Areas of contact caused by the pressing object produce a lighted area that can be detected by the light detecting means. The output from the light detecting means may be processed by a computer and an image of the contact area produced by the pressing object can be displayed on a monitor or processed to operate an electro-mechanical control.

Claims

1. A tactile sensor device comprising:

a first sheet-like element of light conducting material having opposed surfaces and an edge,

a second sheet-like element, generally coextensive with said first sheet-like element,

at least one of said sheet-like elements being resiliently deformable so that localized portions of said first and second sheet-like elements will contact each other in response to localized pressure applied to force the sheet-like elements towards each other,

means for illuminating the interior of said first sheet-like element through said edge thereof,

light detecting means generally coextensive with the first sheet-like elements and positioned on one side thereof to detect light exiting from said first sheet-like element through one of said opposed surfaces thereof.

2. The tactile sensor of claim 1, and further including:

spacer means for separating said first and second sheet-like elements when said elements are not forced towards each other, said spacer means having a plurality of apertures therethrough to permit localized portions of said sheet-like elements adjacent said apertures to be pressed into contact with each other.

3. The tactile sensor of claim 1, wherein one of said sheet-like elements has a plurality of projections integral with a surface thereof and extending towards the other of said sheet-like elements.

4. The tactile sensor of claim 3, wherein the tips of said projections contact the surface of said other of said sheet-like elements to separate said sheet-like elements.

5. The tactile sensor of claim 3, wherein the tips of said projections contact the surface of said other of said sheet-like elements and can move along said surface in response to shear forces acting on said sheet-like elements.

6. The tactile sensor of claim 1, wherein said first sheet-like element is impregnated with a dye that is excited by light.

7. A tactile sensor comprising:

a plurality of light conducting fibers arranged in side by side relationship, said fibers being grouped in arrays, each array having at least one fiber, the fibers of each array having their surfaces exposed at a point thereon, with the exposed surfaces of the arrays of fibers being at predetermined positions.

a resilient element adjacent said arrays of light conducting fibers and being locally deformable into and out of contact with the exposed surfaces of the light conducting arrays of fibers in response to the presence or absence, respectively, of localized pressure exerted by an object,

means for introducing light into the ends of the fibers of said arrays,

means for detecting changes in the intensity of light in each of the arrays of fibers.

8. A tactile sensor as set forth in claim 7 and further including a spacer element disposed between said arrays of light conducting fibers and said resiient member, said spacer element having a plurality of apertures through which said resilient member may be pressed into contact with the exposed surfaces of said light conducting fibers.