Thermal image converters

Claim 2

A thermal image converter comprising: a. an elongate envelope disposed about a central longitudinal axis; b. a slice of pyroelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope; c. a window transparent to infra-red radiation to admit a thermal scene to said first face; d. an electron gun to direct an incident beam of elecrons towards said second face; e. an electrode comprising a conducting layer on said first face and transparent to infra-red radiation to induce a negative charge on said second face said negative charge to reflect electrons in said incident beam to form a reflected beam; f. a cylindrical anode coaxial with said envelope, g. a cylindrical beam forming tube coaxial with said envelope, of lesser diameter than said cylindrical anode, mounted in overlapping relationship with said cylindrical anode and in closer proximity to said second face than said cylindrical anode, h. a viewing means; whereby, in use, a thermal scene admitted to said first face induces a charge distributioN on said second face according to the temperature distribution in the thermal scene to both modulate and deflect electrons in said reflected beam and said reflected beam to strike the viewing means to reproduce visually the charge distribution on said second face, and the incident electron beam passes through said cylindrical anode and said beam forming tube to be constrained to the required shape.

Claim 3

A thermal image converter according to claim 1 said electrode comprising graphite.

Claim 4

A thermal image converter according to claim 1 wherein the slice of pyroelectric material comprises single crystal triglycine sulphate.

Claim 5

A thermal image converter according to claim 1 wherein the window comprises germanium.

Claim 6

A thermal image converter according to claim 1 additionally including an end plate of the envelope, a tube maintained in said end plate and said tube receiving the viewing means.

Claim 7

A thermal image converter according to claim 1 wherein the viewing means comprises a fluorescent screen.

Claim 8

A thermal image converter comprising: a. an elongate envelope disposed about a central longitudinal axis; b. a slice of pyrolelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope; c. window transparent to infra-red radiation to admit a thermal scene to said first face; d. an electron gun to direct an incident beam of electrons towards said second face, said electron gun mounted on an axis convergent with the longitudinal axis of the envelope, e. an electrode comprising a conducting layer on said first face and transparent to infra-red radiation to induce a negative charge on said second face said negative charge to reflect electrons in said incident beam to form a reflected beam; f. a cylindrical anode coaxial with said envelope, g. a cylindrical beam forming tube coaxial with said envelope of lesser diameter than said cylindrical anode, mounted in overlapping relationship with said cylindrical anode and in closer proximity to said second face than said cylindrical anode; h. a viewing means; i. a pair of opposed electromagnetic coils one mounted either side of the envelope on an axis normal to the longitudinal axis of the envelope to divert electrons in the incident beam to a path coaxial with the longitudinal axis of the envelope and to divert electrons in the reflected beam to a path whose axis is convergent with the longitudinal axis of the envelope and which is the mirror image in the longitudinal axis of the axis on which the elctron gun is mounted; whereby in use, a thermal scene admitted to said first face induces a charge distribution on said second face according to the temperature distribution in the thermal scene to both modulate and deflect electrons in said reflected beam and said reflected beam to strike the viewing means to reproduce visually the charge distribution on said second face, and the incident electron beam passes through said cylindrical anode and said beam forming tube to be constrained to the required shape.

Claim 9

A thermal image converter comprising: a. an elongate envelope disposed about a central longitudinal axis; b. a slice of pyrolelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope; c. window transparent to infra-red radiation to admit a thermal scene to said first face; d. an electron gun to direct an incident beam of electrons towards said second face, said electron gun mounted on an axis convergent with the longitudinal axis of the envelope, e. an electrode comprising a conducting layer on said first face and transparent to infra-red radiation to induce a negative charge on said second face said negative charge to reflect electrons in said incident beam to form a reflected beam; f. a cylindrical anode coaxial with said envelope, g. a cylindrical beam forming tube coaxial with said envelope of lesser diameter than said cylindrical anode, mounted in overlapping relationship with said cylindrical anode and in closer proximity to said second face than said cylindrical anode; h. a viewing means; i. a pair of opposed electromagnetic coils one mounted either side of the envelope on an axis normal to the longitudinal axis of the envelope to divert electrons in the incident beam to a path coaxial with the longitudinal axis of the envelope and to divert electrons in the reflected beam to a path whose axis is convergent with the longitudinal axis of the envelope and which is the mirror image in the longitudinal axis of the axis on which the elctron gun is mounted; whereby in use, a thermal scene admitted to said first face induces a charge distribution on said second face according to the temperature distribution in the thermal scene to both modulate and deflect electrons in said reflected beam and said reflected beam to strike the viewing means to reproduce visually the charge distribution on said second face, and the incident electron beam passes through said cylindrical anode and said beam forming tube to be constrained to the required shape.

Claim 10

A thermal image converter according to claim 7 additionally including a tubular anode and stop with a central aperture mounted coaxially with the electron gun.

Claim 11

A thermal image converter according to claim 8 additionally including a guide tube, tubular anode, and beam shaping ring mounted in coaxial relationship about the axis followed by the diverted electrons in the reflected beam.

Claim 12

A thermal image converter according to claim 9 additionally including an end plate of the envelope, a tube maintained in said end plate and said tube receiving the viewing means.

Claim 13

A thermal image converter according to claim 10 wherein the viewing means comprises a fluorescent screen.

Claim 14

A thermal image converter according to claim 11 wherein said electrode comprises graphite.

Claim 15

A thermal image converter according to claim 12 wherein the slice of pyroelectric material compriseS single crystal triglycine sulphate.

Claim 16

A thermal image converter according to claim 13 wherein said window comprises germanium.

Claim 17

A thermal image converter comprising: a. an elongate envelope disposed about a central longitudinal axis; b. a slice of pyroelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope, said pyroelectric material comprising a single crystal of tri-glycine sulphate; c. a germanium window to admit a thermal scene to said first face; d. an electron gun to direct an incident beam of electron towards said second face, said electron gun mounted on an axis convergent with the longitudinal axis of the envelope; e. a tubular anode and stop with a central aperture mounted coaxially with said electron gun; f. a cylindrical anode coaxial with said envelope; g. a cylindrical beam forming tube coaxial with said envelope of lesser diameter than said cylindrical anode, mounted in overlapping relationship with said cylindrical anode and in closer proximity to said second face than said cylindrical anode; h. a graphite electrode comprising a layer on said first face; i. a pair of opposed elctromagnetic coils one mounted one either side of the envelope on an axis normal to the longitudinal axis of the envelope to divert electrons in the incident beam to a path coaxial with the longitudinal axis of the envelope and to divert electrons in the reflected beam to a path whose axis is convergent with the longitudinal axis of the envelope and which is the mirror image in the longitudinal axis on which the electron gun is mounted; j. a guide tube, tubular anode, and beam shaping ring mounted in coaxial relationship about the axis followed by the diverted electrons in the reflected beam; k. an end plate of the envelope, a tube maintained in said end plate, and a fluorescent screen mounted in said tube, whereby in use, a thermal scene admitted to said first face induces a charge distribution on said second face according to the temperature distribution in the thermal scene to both modulate and deflect electrons in said reflected beam and said reflected beam to strike the fluourescent screen to reproduce visually the charge distribution on said second face, and the incident beam passes through said cylindrical anode and said beam forming tube to be constrained to the required shape.

Claim 18

A thermal image converter comprising: a. an elongate envelope disposed about a central longitudinal axis; b. a slice of pyroelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope, said pyroelectric material comprising a single crystal of tri-glycine sulphate; c. a germanium window to admit a thermal scene to said first face; d. an electron gun to direct an incident beam of electron towards said second face, said electron gun mounted on an axis convergent with the longitudinal axis of the envelope; e. a tubular anode and stop with a central aperture mounted coaxially with said electron gun; f. a cylindrical anode coaxial with said envelope; g. a cylindrical beam forming tube coaxial with said envelope of lesser diameter than said cylindrical anode, mounted in overlapping relationship with said cylindrical anode and in closer proximity to said second face than said cylindrical anode; h. a graphite electrode comprising a layer on said first face; i. a pair of opposed elctromagnetic coils one mounted one either side of the envelope on an axis normal to the longitudinal axis of the envelope to divert electrons in the incident beam to a path coaxial with the longitudinal axis of the envelope and to divert electrons in the reflected beam to a path whose axis is convergent with the longitudinal axis of the envelope and which is the mirror image in the longitudinal axis on which the electron gun is mounted; j. a guide tube, tubular anode, and beam shaping ring mounted in coaxial relationship about the axis followed by the diverted electrons in the reflected beam; k. an end plate of the envelope, a tube maintained in said end plate, and a fluorescent screen mounted in said tube, whereby in use, a thermal scene admitted to said first face induces a charge distribution on said second face according to the temperature distribution in the thermal scene to both modulate and deflect electrons in said reflected beam and said reflected beam to strike the fluourescent screen to reproduce visually the charge distribution on said second face, and the incident beam passes through said cylindrical anode and said beam forming tube to be constrained to the required shape.

Claim 19

A thermal image converter comprising an elongated envelope disposed about a central longitudinal axis; a slice of pyroelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope; a window transparent to infra-red radiation for admitting a thermal scene to said first face; an electron gun for directing an incident beam of electrons towards said second face; a beam forming arrangement for forming said incident beam to flood said second face, said beam forming arrangement comprising a cylindrical anode coaxial with said envelope and a cylindrical beam forming tube, of different diameter than said anode, mounted in coaxial overlapping relationship with said cylindrical anode and in closer proximity to said second face than said cylindrical anode, the incident electron beam passing through said cylindrical anode and said beam forming tube to be constrained to a required shape; an electrode operative to induce a negative charge on said second face which negative charge reflects electrons in said incident beam to form a reflected beam; and a viewing means; whereby a thermal scene admitted to said first face induces a charge distribution on said second face according to the temperature distribution in the thermal scene to both modulate and deflect electrons in said reflected beam and said reflected beam strikes the viewing means to reproduce visually the charge distribution on said second face.

Claim 20

A thermal image converter comprising an elongated envelope disposed about a central longitudinal axis; a slice of pyroelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope; a window transparent to infra-red radiation for admitting a thermal scene to said first face; an electron gun for directing an incident beam of electrons towards said second face; a beam forming arrangement for forming said incident beam to flood said second face, said beam forming arrangement comprising a cylindrical anode coaxial with said envelope and a cylindrical beam forming tube, of different diameter than said anode, mounted in coaxial overlapping relationship with said cylindrical anode and in closer proximity to said second face than said cylindrical anode, the incident electron beam passing through said cylindrical anode and said beam forming tube to be constrained to a required shape; an electrode operative to induce a negative charge on said second face which negative charge reflects electrons in said incident beam to form a reflected beam; and a viewing means; whereby a thermal scene admitted to said first face induces a charge distribution on said second face according to the temperature distribution in the thermal scene to both modulate and deflect electrons in said reflected beam and said reflected beam strikes the viewing means to reproduce visually the charge distribution on said second face.

Claim 21

A thermal image converter Comprising an elongated envelope disposed about a central longitudinal axis; a slice of pyroelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope; a window transparent to infra-red radiation to admit a thermal scene to said first face; an electron gun operative to direct an incident beam of electrons towards said second face; an electrode for inducing a negative charge on said second face, said negative charge being operative to reflect electrons in said incident beam to form a reflected beam; a beam forming arrangement operative to form said incident beam to flood said second face; and a viewing means; said electron gun being mounted on an axis convergent with the longitudinal axis of the envelope and additionally including deflection means comprising a pair of opposed electromagnetic coils one mounted either side of the envelope on an axis normal to the longitudinal axis of the envelope, said deflection means being operative to divert electrons in the incident beam to a path coaxial with the longitudinal axis of the envelope and being operative to divert electrons in the reflected beam to a path whose axis diverges from the longitudinal axis of the envelope and is the mirror image relative to said longitudinal axis of the axis on which the electron gun is mounted, whereby, in use, a thermal scene admitted to said first face induces a charge distribution on said second face to both modulate and deflect electrons in said reflected beam, and said reflected beam strikes the viewing means to reproduce visually the charge distribution on said second face.

Claim 22

A thermal image converter Comprising an elongated envelope disposed about a central longitudinal axis; a slice of pyroelectric material mounted towards one end of the envelope and having first and second substantially plane parallel faces disposed transversely to said envelope; a window transparent to infra-red radiation to admit a thermal scene to said first face; an electron gun operative to direct an incident beam of electrons towards said second face; an electrode for inducing a negative charge on said second face, said negative charge being operative to reflect electrons in said incident beam to form a reflected beam; a beam forming arrangement operative to form said incident beam to flood said second face; and a viewing means; said electron gun being mounted on an axis convergent with the longitudinal axis of the envelope and additionally including deflection means comprising a pair of opposed electromagnetic coils one mounted either side of the envelope on an axis normal to the longitudinal axis of the envelope, said deflection means being operative to divert electrons in the incident beam to a path coaxial with the longitudinal axis of the envelope and being operative to divert electrons in the reflected beam to a path whose axis diverges from the longitudinal axis of the envelope and is the mirror image relative to said longitudinal axis of the axis on which the electron gun is mounted, whereby, in use, a thermal scene admitted to said first face induces a charge distribution on said second face to both modulate and deflect electrons in said reflected beam, and said reflected beam strikes the viewing means to reproduce visually the charge distribution on said second face.