# US 4,398,115 A · Temperature probe using a plate of quartz

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- Number: US 4,398,115 A
- Document ID: US4398115A
- Status: Granted
- Kind: A
- Application number: 06/265,928
- Filed: 1981-05-21
- Granted: 1983-08-09
- Earliest claimed: 1980-05-23
- Assignees: Quartz et Electronique; Centre National de la Recherche Scientifique (CNRS)
- Inventors: Jean-Jacques Gagnepain; Daniel Hauden; Roger Coquerel; Claude Pegeot
- Web page: https://patentgrep.com/patent/US4398115A

## CPC

- G01K 7/32: using change of resonant frequency of a crystal
- G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00)

## Abstract

A quartz crystal plate (L) is used in determining the frequency of a frequency generator, and the frequency determined by said plate is variable as a function of temperature. The quartz plate constitutes the substrate for a surface acoustic wave device, e.g. a resonator or a delay line using comb transducers (1 & 2). The orientation in the quartz crystal of the plane over which the acoustic wave propagates, and the direction of propagation in said plane are defined in terms of a doubly rotated frame of reference as follows: the plate being a double rotation cutting plate defined by yxwl: .phi./.theta., one large surface of which is used for the propagation of a surface wave whose direction of propagation makes an angle .psi. with the second axis of rotation, where the first angle .phi. lies in the range 9.degree.24' to 13.degree.24', the second angle .theta. lies in the range 57.degree.24' to 61.degree.24', and the angle .psi. lies in the range 33.degree. to 37.degree..

## Claims

### Claim 1

A temperature probe comprising a surface acoustic wave propagation device used in a frequency generator device, said surface acoustic wave propagation device having a characteristic frequency which varies in accordance with the temperature and being composed of a doubly rotated quartz cutting plate defined by:
yxwl: 9.degree.24' to 13.degree.24'/57.degree.24' to 61.degree.24'
the surface wave being propagated on a large surface of the plate in accordance with a direction making an angle of between 33.degree. and 37.degree. with the axis of second rotation.

### Claim 2 (depends on 1)

The temperature probe of claim 1, wherein the quartz cutting plate is defined by:
yxwl: 11.degree.24'/59.degree.24'
and the surface wave is propagated in accordance with a direction making an angle of 35.degree. with the axis of second rotation.