Pressure and temperature sensor transducer array

• US 5,984,874 A
• Filed: 08/14/1997
• Issued: 11/16/1999
• Est. Priority Date: 08/14/1997
• Status: Expired due to Term

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: Cerwin, Stephen A.
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US08/911,216
• Time in Patent Office: 824 Days
• Field of Search: 73/800, 250/525, 356/32, 600/486, 600/488, 600/545, 600/561
• US Class Current: 600/549
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: G01K 1/045 temperature indication combined with the indication of another variable indicating of human comfort G01W1/17

Abstract

A pressure or temperature sensor array utilizing a combination of liquid crystal material and charge coupled device (CCD) sensor array. The device generally comprises a liquid crystal material enclosed in a planar capsule, one side of which has a flexible outer membrane which is placed on the surface whose pressure and/or temperature is to be measured; a light source used to illuminate the liquid crystal material; and a charge coupled device (CCD) array which detects the variations in the optical signature of the liquid crystal material due to changes in pressure or temperature. The device may further include an optical waveguide for controlling transmission of light from the light source to the liquid crystal material.

Claims

1. An apparatus for measuring pressure or temperature over a surface area, comprising:

a liquid crystal material enclosed in a planar capsule having a flexible outer membrane, said liquid crystal material having an optical signature responsive to variations in pressure or temperature over said surface area, said optical signature comprising color and amplitude variations in said liquid crystal material; and

a color sensitive charge coupled device sensor array capable of detecting and mapping said optical signature of said liquid crystal material due to said variations in pressure or temperature.

2. The apparatus of claim 1, further comprising a light source for illuminating said liquid crystal material.

3. The apparatus of claim 2, wherein said light source is external to said liquid crystal material and said sensor array, and said apparatus further comprises a light waveguide, said light waveguide positioned to direct light from said external light source to said liquid crystal material.

4. The apparatus of claim 1, wherein said apparatus is used to measure and record blood pressure through contact between said flexible outer membrane of said liquid crystal material and an area of skin over an adjacent blood vessel.

5. An apparatus for measuring pressure or temperature over a surface area, comprising:

a liquid crystal material enclosed in a planar capsule and having an optical signature, said optical signature comprising color and amplitude variations in said liquid crystal material, said planar capsule having at least one flexible outer membrane for placement on said surface area;

a polychromatic light source used to illuminate said optical signature of said liquid crystal material, said optical signature representative of variations in pressure and temperature on said surface area; and

a color sensitive charge coupled device sensor array capable of detecting and mapping said optical signature representative of said variations in pressure or temperature.

6. The apparatus of claim 5, wherein said light source is external to said liquid crystal material and said sensor array, and said apparatus further comprises a waveguide coupled to said external light source, said waveguide operating to enhance illumination of said liquid crystal material while minimizing direct illumination of said charge coupled device sensor array.

7. The apparatus of claim 6, wherein said waveguide is located between said liquid crystal material and said CCD array.

8. The apparatus of claim 6, wherein said waveguide further comprises a plurality of non-parallel faces forming a wedge shape favoring optical propagation toward said liquid crystal material.

9. The apparatus of claim 6, wherein said waveguide uses the refractive indices at an interface of said waveguide with said planar capsule and said CCD array to achieve a preferential illumination of said liquid crystal material.

10. The apparatus of claim 6, wherein said waveguide further comprises partially reflective coatings to achieve a desired illumination of said liquid crystal material.