Patent US3603794A successfully refreshed from Google Patents.
US3603794A
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US
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Apparatus for transducing infrared images into visible images utilizing a liquid light control layer
Assignee: BASF Schweiz AG
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Filing: 1970-07-10
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Granted: 1971-09-07
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Expires: 1990-07-10
Abstract
Abstract Apparatus for making incoming infrared rays visible includes an infrared optical system which serves to focus the rays through an optical grating onto the surface of a deformable liquid film deposited on a plane face of a transparent prism, the prism being so disposed in the path of a Schlieren-optical system that a beam of visible light produced by a source enters the liquid film from the baCk, is totally internally reflected at its surface adjacent the grating onto a concave mirrored surface of the prism which returns the beam to the liquid where it is again totally internally reflected by the liquid surface and then imaged on the bar-and-slot system of the schlieren-optics. In the absence of incoming infrared rays, the surface of the liquid film remains undeformed and the beam of visible light is turned back into its source. Upon deformation of the liquid surface by incoming infrared rays, visible light returning from the prism passes through the slots of the bar-and-slot system to establish an observable image of the deformation.
Inventors
- 👤 Fred Mast
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:30
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/50
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
236 words
Apparatus for making infrared light visible comprising a transparent prism having at least one plane face; a liquid film deposited on said plane face, the film being deformable by incident infrared radiation and the amount by which the film deforms being related to the intensity of the infrared radiation; an optical grating over said liquid film; a concave mirror; a schlieren-optical system including a bar and slot system and a source for projecting a beam of visible light; the concave mirror, the bar and slot system and the light source being positioned relative to each other and to the prism to cause the bar and slot system to be imaged on itself so that the light beam from said source is projected through said prism to be totally internally reflected at the surface of the liquid film adjacent said grating and then reflected by said concave mirror back through the prism to be again totally internally reflected at said adjacent surface and then imaged on said bar and slot system, the maximum linear diameter of the light beam in the plane of the bar and slot system being smaller than the product of the spacing of the lines in the optical grating, the refractive index of the material of the prism and the radius of curvature of the concave mirror divided by the greatest distance between the concave mirror and the surface of the liquid film.
Claim 2
Dependent Claim
236 words
Apparatus for making infrared light visible comprising a transparent prism having at least one plane face; a liquid film deposited on said plane face, the film being deformable by incident infrared radiation and the amount by which the film deforms being related to the intensity of the infrared radiation; an optical grating over said liquid film; a concave mirror; a schlieren-optical system including a bar and slot system and a source for projecting a beam of visible light; the concave mirror, the bar and slot system and the light source being positioned relative to each other and to the prism to cause the bar and slot system to be imaged on itself so that the light beam from said source is projected through said prism to be totally internally reflected at the surface of the liquid film adjacent said grating and then reflected by said concave mirror back through the prism to be again totally internally reflected at said adjacent surface and then imaged on said bar and slot system, the maximum linear diameter of the light beam in the plane of the bar and slot system being smaller than the product of the spacing of the lines in the optical grating, the refractive index of the material of the prism and the radius of curvature of the concave mirror divided by the greatest distance between the concave mirror and the surface of the liquid film.
Claim 3
Dependent Claim
50 words
Apparatus according to claim 1 in which the surfaces of the bars of the bar and slot system are mirroreD and the light source is arranged to project said beam onto said mirrored surfaces so that the beam is then projected through said prism and back to the mirrored bars.
Claim 4
Dependent Claim
18 words
Apparatus according to claim 2 in which said concave mirror comprises a mirrored concave surface of said prism.
Claim 5
Dependent Claim
59 words
Apparatus according to claim 3 in which that surface of the prism through which said beam enters from said bar and slot system is concave having a center of curvature in the plane of but distant from said bar and slot system to prevent light scattered from the concave surface from being imaged on said bar and slot system.
Claim 6
Dependent Claim
131 words
Apparatus according to claim 2 including second and third concave mirrors positioned in the image path which images the bar and slot system upon itself, the second concave mirror being in the plane of the bar and slot system but displaced to one side thereof and the center of curvature of the first mentioned concave mirror falling between the bar and slot system and said second concave mirror so the reflected beam emergent from said prism is reflected by said second concave mirror onto the third concave mirror which reflects the beam back to the second concave mirror, through the prism back to the first mentioned concave mirror which reflects the beam back to the bar and slot system, the beam being totally internally reflected at said adjacent surface four times.
Claim 7
Dependent Claim
18 words
Apparatus according to claim 5 in which said concave mirror comprises a mirrored concave surface of said prism.
Claim 8
Dependent Claim
59 words
Apparatus according to claim 5 in which that surface of the prism through which said beam enters from said bar and slot system is concave having a center of curvature in the plane of but distant from said bar and slot system to prevent light scattered from the concave surface from being imaged on said bar and slot system.
References Cited (Backward Citations)
US3397313A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-06 | 1975-03-08 | 1975-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-06 | 1979-03-08 | 1979-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-06 | 1983-03-08 | 1983-09-07 | $7700.00 | Window Closed / Lapsed |