Optical sensors for detecting physical parameters

Claim 2

A transducer apparatus for detecting a physical parameter comprising: a member which modulates light; means for supplying light to the member, so that when the member is moved by said physical parameter, said member modulates the light transmitted by the member; and means for detecting modulations of the light by the member to detect said physical parameter.

Claim 3

The transducer apparatus of claim 1, wherein said member is piezoelectric member and transmits light, wherein light supplied to the member by the light supplying means is transmitted through the member, said apparatus further comprising means for vibrating the member in a direction transverse to the light transmitted in the member so that the vibrations of the member is modulated by the physical parameter, and so that said modulations of the vibrations also modulate the light transmitted by the member.

Claim 5

The apparatus of claim 2, wherein said member is a tuning fork type transducer, wherein the light is supplied to the member at the base of the fork so that the light is transmitted towards and through the tines of the member, and wherein said detecting means includes an optical fiber for receiving light transmitted through the member and emitting from the ends of the tines of the member, and wherein the physical parameter modulates the amount of light emitting from the ends of the tines and received by the optical fiber.

Claim 6

The apparatus of claim 2, wherein said member is a tuning fork type transducer, wherein the indices of refraction of the member and its environment are such that the member acts as a light guide, wherein the two tines bend with their ends facing each other, wherein the light is supplied to the base of the fork towards one of the tines, guided by said tine towards and passes out of its end, transmitted towards and received by the end of the other tine, and guided by the other tine towards the base of the fork for detection by the detection means, wherein the two tines taper towards their ends for focusing the light transmitted between their ends, thereby increasing the magnitude of the modulation caused by the physical parameter, wherein the two tines taper towards their ends for focusing the light transmitted between their ends, wherein their ends are in the shape of two knife edges facing each other, and wherein the vibrations are transverse to the two knife edges, thereby increasing the magnitude of the modulation caused by the physical parameter.

Claim 7

The apparatus of claim 2, wherein the member comprises a first and a second closed-end tuning fork, said apparatus further comprises gratings on the two tines of the two forks in matching positions, wherein the gratings on the first tuning fork are light absorbent, and wherein the light supplied passes through the first tuning fork between the gratings thereon to impinge on the second tuning fork.

Claim 8

The apparatus of claim 2, wherein the member comprises a portion in the form of a closed-end tuning fork and a second portion in the form of two arms with their bases integral with and originating from the two ends of the elongated space between the two tines extending towards each other with space left therebetween, the two bases or ends of the closed-end tuning fork defining a first and a second side of the member, said apparatus further comprising a mirror connected to the first side of the member, said two tines having fingers extending towards the space between the ends of the two arms, and wherein the light is supplied to the second side of the member so that light is transmitted down one of the two arms, through the space between the two arms and into the other arm, is reflected by the mirror at the first side of the member and transmitted back through the two arms towards the second side of the member so that when the two tines vibrate, the two fingers will modulate the amount of light transmitted between the two arms to detect the physical parameter.

Claim 9

The transducer apparatus of claim 1, wherein the member is piezoelectric and transmits light, wherein the light supplied to the member is transmitted through the member, said apparatus further comprising electrical means for moving the member in a direction transverse to the light transmitted in the member so that the movement of the member is modulated by the physical parameter, and so that said modulations of the vibrations also modulate the light transmitted by the member.

Claim 10

A transducer apparatus for detecting a physical parameter comprising: light transmission means; two flexible bars which bend when influenced by said physical parameter, said bars having fingers which, when the bars flex under the influence of said physical parameter, move in such directions as to change the amount of light transmitted by the light transmission means; and means for detecting the change in the amount of light transmitted by the light transmission means to detect the physical parameter.

Claim 11

A transducer apparatus for detecting a physical parameter comprising: light transmission means; two flexible bars which bend when influenced by said physical parameter, said bars having fingers which, when the bars flex under the influence of said physical parameter, move in such directions as to change the amount of light transmitted by the light transmission means; and means for detecting the change in the amount of light transmitted by the light transmission means to detect the physical parameter.

Claim 12

A transducer apparatus for detecting a physical parameter comprising: two flexible elongated members connected or integral with each other at or near one end, said two members capable of transmitting light so that, when the free ends of the two members are moved relative to each other by the physical parameter, the amount of light transmitted between the two members is changed; means for supplying light to the two members; and means for detecting the change in the amount of light transmitted between the two members to detect the physical parameter.

Claim 13

A transducer apparatus for detecting a physical parameter comprising: two flexible elongated members connected or integral with each other at or near one end, said two members capable of transmitting light so that, when the free ends of the two members are moved relative to each other by the physical parameter, the amount of light transmitted between the two members is changed; means for supplying light to the two members; and means for detecting the change in the amount of light transmitted between the two members to detect the physical parameter.

Claim 14

A transducer apparatus for detecting a physical parameter comprising: a resonator whose torsional resonance frequency is influenced by the physical parameter, said resonator having a light reflective surface so that when it vibrates in a torsional mode, light reflected by it will change direction in an angular oscillation with the same frequency as the torsional vibration; means for supplying a light beam towards said resonator; and means for detecting the modulations of the angular oscillation frequency of light reflected by the resonator to detect the physical parameter.

Claim 15

A transducer apparatus for detecting a physical parameter comprising: a resonator whose torsional resonance frequency is influenced by the physical parameter, said resonator having a light reflective surface so that when it vibrates in a torsional mode, light reflected by it will change direction in an angular oscillation with the same frequency as the torsional vibration; means for supplying a light beam towards said resonator; and means for detecting the modulations of the angular oscillation frequency of light reflected by the resonator to detect the physical parameter.

Claim 16

A transducer apparatus for detecting a physical parameter comprising: a resonator whose flexural resonance frequency is influenced by the physical parameter, said resonator having a light absorbent surface; means for supplying light towards the resonator; light reflective surface behind the resonator so that when the resonator vibrates, the amount of light supplied by the light supplying means and reflected by the light reflective surface is modulated by the flexural vibrations of the resonator; and means for detecting said modulations of the reflected light to detect the physical parameter.

Claim 17

A transducer apparatus for detecting a physical parameter comprising: a resonator whose flexural resonance frequency is influenced by the physical parameter, said resonator having a light absorbent surface; means for supplying light towards the resonator; light reflective surface behind the resonator so that when the resonator vibrates, the amount of light supplied by the light supplying means and reflected by the light reflective surface is modulated by the flexural vibrations of the resonator; and means for detecting said modulations of the reflected light to detect the physical parameter.

Claim 18

A transducer apparatus for detecting a physical parameter comprising: a resonator whose flexural resonance frequency is influenced by the physical parameter, said resonator having a light reflective surface; means for supplying light towards the resonator; light absorbent surface shielding a portion of the resonator from light supplied by the light supplying means so that when the resonator vibrates, the amount of light supplied by the light supplying means and reflected by the resonator is modulated by the flexural vibrations of the resonator; and means for detecting said modulations of the reflected light to detect the physical parameter.

Claim 19

A transducer apparatus for detecting a physical parameter comprising: a resonator whose flexural resonance frequency is influenced by the physical parameter, said resonator having a light reflective surface; means for supplying light towards the resonator; light absorbent surface shielding a portion of the resonator from light supplied by the light supplying means so that when the resonator vibrates, the amount of light supplied by the light supplying means and reflected by the resonator is modulated by the flexural vibrations of the resonator; and means for detecting said modulations of the reflected light to detect the physical parameter.