Remote passive temperature sensor

Claim 2

A non-electrical, optically read condition sensor apparatus for determining the condition at a remote location by transmitting a radiant energy beam to the remote location and measuring a reflected return beam, the apparatus comprising in combination: a local ground instrument comprising; means for generating an interrogation beam of radiant energy; means directing said interrogation beam to a remotely located corner-cube sensor; and, return radiation sensing means for sensing the intensity of the reflected returned beam; a passive, unpowered, remotely located corner cube sensor means comprising; a reflective corner cube having a plurality of adjoining reflective faces at right angles to each other; a condition sensing area on one of said reflective corner cube faces, said sensing area including condition responsive bi-level film cantilever member means forming a part of said condition sensing area, said bi-level film cantilever member means consisting of two different materials which have different expansion coefficients whereupon as the condition changes the bi-level film cantilever member means bends to a degree dependent on the amount of change of the condition sensed and thus deflects more or less of the return radiation away from the local ground instrument.

Claim 3

A non-electrical, optically read condition sensor apparatus for determining the condition at a remote location, the apparatus comprising in combination: a local ground instrument comprising; means for generating an interrogation beam of radiant energy having a component λ 1 and a component λ 2 ; means directing said interrogation beam to a remotely located corner-cube sensor; and, return radiation sensing means for sensing the intensity of returned λ 1 and λ 2 components; a passive, unpowered, remotely located corner cube sensor means comprising; a reflective corner cube having three adjoining faces at right angles to each other; a reference area on one of said corner cube faces; λ 2 filter means associated with said reference area of said corner cube for returning said λ 2 component to said local ground instrument without modification; a condition sensing area on said one of said reflective corner cube faces; λ 1 filter means associated with said condition sensing area, said sensing area including condition responsive bi-level film cantilever member means forming a part of said one of said reflective corner cube faces, said bi-level film consisting of two different materials which have different expansion coefficients whereupon as said condition changes, the bi-level film cantilever member means bends to a degree dependent on said condition, and thus deflects more or less of the λ 1 return radiation.

Claim 4

A non-electrical, optically read condition sensor apparatus for determining the condition at a remote location, the apparatus comprising in combination: a local ground instrument comprising; means for generating an interrogation beam of radiant energy having a component λ 1 and a component λ 2 ; means directing said interrogation beam to a remotely located corner-cube sensor; and, return radiation sensing means for sensing the intensity of returned λ 1 and λ 2 components; a passive, unpowered, remotely located corner cube sensor means comprising; a reflective corner cube having three adjoining faces at right angles to each other; a reference area on one of said corner cube faces; λ 2 filter means associated with said reference area of said corner cube for returning said λ 2 component to said local ground instrument without modification; a condition sensing area on said one of said reflective corner cube faces; λ 1 filter means associated with said condition sensing area, said sensing area including condition responsive bi-level film cantilever member means forming a part of said one of said reflective corner cube faces, said bi-level film consisting of two different materials which have different expansion coefficients whereupon as said condition changes, the bi-level film cantilever member means bends to a degree dependent on said condition, and thus deflects more or less of the λ 1 return radiation.

Claim 5

A non-electrical, optically read temperature sensor apparatus for determining the temperature at a remote location, the apparatus comprising in combination: a local ground instrument comprising; means for generating an interrogation beam of radiant energy having a component λ 1 and a component λ 2 ; means directing said interrogation beam to a remotely located corner-cube sensor; and, return radiation sensing means for sensing the intensity of returned λ 1 and λ 2 components; a passive, unpowered, remotely located corner cube sensor means comprising; a reflective corner cube having three adjoining faces at right angles to each other; a reference area on one face of said corner cube; λ 2 filter means associated with said reference area of said corner cube for returning said λ 2 component to said local ground instrument without modification; a temperature sensing area of said reflective corner cube, said sensing area including temperature responsive bi-level film cantilever member means forming a part of said one face, said bi-level film consisting of two different materials which have different thermal expansion coefficients whereupon as temperature changes the bi-level film cantilever member means bends to a degree dependent on absolute temperature and thus deflects more or less of the return radiation.

Claim 6

A non-electrical, optically read temperature sensor apparatus for determining the temperature at a remote location, the apparatus comprising in combination: a local ground instrument comprising; means for generating an interrogation beam of radiant energy having a component λ 1 and a component λ 2 ; means directing said interrogation beam to a remotely located corner-cube sensor; and, return radiation sensing means for sensing the intensity of returned λ 1 and λ 2 components; a passive, unpowered, remotely located corner cube sensor means comprising; a reflective corner cube having three adjoining faces at right angles to each other; a reference area on one face of said corner cube; λ 2 filter means associated with said reference area of said corner cube for returning said λ 2 component to said local ground instrument without modification; a temperature sensing area of said reflective corner cube, said sensing area including temperature responsive bi-level film cantilever member means forming a part of said one face, said bi-level film consisting of two different materials which have different thermal expansion coefficients whereupon as temperature changes the bi-level film cantilever member means bends to a degree dependent on absolute temperature and thus deflects more or less of the return radiation.

Claim 7

A passive condition responsive corner cube reflector means comprising: a reflective corner cube having a plurality of adjoining reflective faces at right angles to each other, at least one of said reflective faces comprising: a wafer of single crystalline silicon having a planar surface coated with a thin film layer of reflective silicon nitride; a plurality of silicon-nitride cantilever member means formed in said silicon nitride layer, said cantilever member means having etched cavities in the silicon beneath them, said silicon nitride having a first expansion coefficient; a layer of material of a different expansion coefficient coated on said cantilever member means so that at a first sensed condition said coated cantilever member means are in the plane of said thin film layer of reflective silicon nitride and at a second sensed condition said coated cantilever member means are warped out of said plane by an amount which is a function of said second sensed condition.

Claim 8

A passive condition responsive corner cube reflector means comprising: a reflective corner cube having a plurality of adjoining reflective faces at right angles to each other, at least one of said reflective faces comprising: a wafer of single crystalline silicon having a planar surface coated with a thin film layer of reflective silicon nitride; a plurality of silicon-nitride cantilever member means formed in said silicon nitride layer, said cantilever member means having etched cavities in the silicon beneath them, said silicon nitride having a first expansion coefficient; a layer of material of a different expansion coefficient coated on said cantilever member means so that at a first sensed condition said coated cantilever member means are in the plane of said thin film layer of reflective silicon nitride and at a second sensed condition said coated cantilever member means are warped out of said plane by an amount which is a function of said second sensed condition.

Claim 9

The corner cube reflector means according to claim 4 in which said first and second sensed condition are temperature.

Claim 10

The corner cube reflector means according to claim 4 in which said first and second sensed condition are humidity.

Claim 11

The condition sensor apparatus according to claim 1 in which the condition responsive bi-level film cantilever member means are responsive to humidity.

Claim 12

The sensor apparatus according to claim 3 in which the temperature sensing area of said reflective corner cube includes λ 1 filter means associated therewith for passing and returning said λ 1 component to said local ground instrument.

Claim 13

The sensor apparatus according to claim 3 in which said bi-level film consists of a first layer of silicon nitride and a second layer selected from a group consisting of aluminum and platinum.

Claim 14

The condition sensor apparatus according to claim 7 in which said bi-level film cantilever member means has one material consisting of a layer of silicon nitride and the other material consisting of a layer of polyimide.

Claim 15

The corner cube reflector means according to claim 5 in which the layer of material of said different expansion coefficient is selected from a group consisting of aluminum and platinum.

Claim 16

The corner cube reflector means according to claim 6 in which the layer of material of said different expansion coefficient consists of a layer of polyimide.