Patent US3655256A successfully refreshed from Google Patents.
US3655256A
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Holography with thermochromic recording materials
Assignee: Advanced Technology Center Inc
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Filing: 1971-01-04
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Granted: 1972-04-11
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Expires: 1991-01-04
Abstract
Abstract Disclosed are methods and apparatus for recording and reproducing optical information in thermochromic materials; exemplary materials are the ternary halides, ternary chalcogenides, and certain transition metal oxides. Methods and apparatus are also disclosed for recording holographic images with infrared radiation and reconstructing infrared holograms in the visible portion of the spectrum.
Inventors
- 👤 Richard N Claytor
- 👤 Dayton D Eden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:23
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/02; B; B41; B41M; B41M5/00; B41M5/26; B41M5/28; B41M5/282; B41M5/283; G03H1/04; G03H1/0402; G03H2001/0441; G03H2222/00; G03H2222/10; G03H2222/16; G03H2224/00; G03H2224/06; G03H2240/00; G03H2240/20; G03H2240/21; G03H2240/22; G03H2260/00; G03H2260/30; G03H2260/35; Y; Y10; Y10S; Y10S359/00; Y10S359/90; Y10S430/00; Y10S430/163
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
22 words
The method as set forth in claim 1 wherein said thermochromic material is Cu2Hg14 and said given temperature is about 66* C.
Claim 2
Dependent Claim
39 words
The method of recording holographic information as claimed in claim 1 wherein the thermochromic material is initially cooled to a temperature near the low-temperature end of the hysteresis loop, and directly thereafter is heated to the aforementioned given temperature.
Claim 3
Dependent Claim
64 words
The method of recording holographic information as claimed in claim 1 wherein the material is initially heatEd to a temperature at least as high as the upper limit of the hysteresis loop prior to establishing said given temperature, so as to irretrievably erase any latent images in said thermochromic material prior to directing said beams of coherent radiation at the surface of said material.
Claim 4
Dependent Claim
60 words
The method as set forth in claim 1 and including the further steps of rendering the recorded interference pattern immune to change by cooling the material to a temperature near the low-temperature end of the hysteresis loop, and subsequently recovering said holographic information by restoring the temperature of the film to approximately the temperature at which said hologram was recorded.
Claim 5
Dependent Claim
68 words
The method as set forth in claim 1 and including the further steps of temporarily rendering the recorded interference pattern immune to change by temporarily lowering the temperature of the entire material below the hysteresis loop, and subsequently causing said holographic information to reappear by raising the temperature of the material to a temperature at least as great as said given temperature but less than an erasing temperature.
Claim 6
Independent Claim
219 words
The method of producing a hologram of the infrared properties of an object, comprising the steps of: a. establishing a thermochromic film at a given temperature, said material being characterized as an absorber of infrared energy and having a reflectance hysteresis loop associated with changes in temperature over a certain range, the hysteresis loop being bounded by a maximum saturation temperature associated with its low temperature reflectance and a minimum saturation temperature associated with its high temperature reflectance, and said given temperature being between the maximum and minimum saturation temperature; and b. directing first and second beams of mutually coherent infrared energy onto the surface of said thermochromic film in a way such that they intersect to form an interference pattern thereon, said first beam containing information about the optical properties of said object and said second beam having a fixed phase relation with said first beam, and the power of said beams being adequate to permit absorption of sufficient energy to cause a rapid transition from one reflectance to another within the loop, and the time of transition being a time period which is not appreciably greater than the ratio of the square of a given diffusion length and the film''s thermal diffusivity, wherein the diffusion length is established by the resolution required to record said interference pattern.
Claim 7
Independent Claim
307 words
The method of producing a visible image of the infrared properties of an object, comprising the steps of: a. establishing a film of thermochromic material at a temperature at which it exhibits at least a double-valued function of reflectance versus temperature, said material having a reflectance hysteresis loop associated with changes in temperature over a certain range; b. producing an object beam and a reference beam from a source of coherent infrared energy; c. directing said object beam at said object such that the infrared energy scattered from said object impinges on a recording medium comprising the film of thermochromic material which is at the above-mentioned temperature; d. directing said reference beam onto said thermochromic material so that the beams form a finely detailed interference pattern and the power of said beams being adequate to permit absorption of sufficient energy to cause a rapid transition from one reflectance to another within the loop, whereby the irradiated portions of the thermochromic film have their reflectance changed so as to produce a visible image of said interference pattern on the surface of said film, and the time of transition being a time period which is not appreciably greater than the ratio of the square of a given diffusion length and the film''s thermal diffusivity, with the diffusion length being established by the resolution required to record said interference pattern; e. photogRaphing said recording medium to produce a photographic replica of said visible image; f. reducing the size of said photographic replica by a factor corresponding to the ratio of the wavelength of the recording infrared beam to the wavelength of the reconstructing beam which is to be used; and g. passing a beam of coherent radiation of visible wavelength through the reduced photographic replica to accomplish the reconstruction of a visible image of the infrared properties of the object.
Claim 8
Dependent Claim
57 words
The method as set forth in claim 8 wherein: a. said beam of coherent infrared energy is the optical output of a carbon-dioxide laser; b. said photographic replica is reduced to approximately one-sixteenth the size of said visible image; and c. said beam of coherent radiation of visible wavelength is the optical output of a helium-neon laser.
Claim 9
Dependent Claim
214 words
Apparatus for recording a holographic image of the optical properties of an object, comprising; a. a film of thermochromic material having a reflectance hysteresis loop associated with changes in temperature over a certain range, the refleftance hysteresis loop of said material being bounded by a maximum saturation temperature associated with its low temperature reflectance and a minimum saturation temperature associated with its high temperature reflectance; b. means for establishing said film at a temperature approximately midway between the minimum and maximum saturation temperatures; c. laser means for generating first and second beams of coherent infrared radiation, said first beam having a fixed phase relation with said second beam; d. means for directing said first beam onto said object and for directing radiation scattered by said object onto said film; e. means for directing said second beam onto said film to intersect with radiation scattered by said object, thereby to produce interference patterns on said film which results in non-uniform heating of said film; and f. means for limiting the film exposure time to a period which is not appreciably greater than the ratio of the square of a given diffusion length and the film''s thermal diffusivity, wherein the diffusion length is established by the resolution which is desired to accurately record said interference pattern.
Claim 10
Dependent Claim
79 words
Apparatus as defined in claim 10 wherein said thermochromic film consists essentially of material selected from the group consisting of: a. material having the general foumula M2M''X4 where M is Ag1 , Cu1 or Tl1 and M'' is Hg2 or Cd2 , and X is a halide; b. material having the general formula MM''2X4 where M is zinc, cadmium or mercury, M'' is aluminum, gallium or indium, and X is sulphur, selenium or tellurium; and c. the vanadium oxides.
Claim 11
Dependent Claim
234 words
Apparatus for producing a hologram of the optical density of an object which is opaque in the visible and at least partially transparent in the infrared,comprising: a. first means including a source of coherent infrared energy for producing an object beam and a reference beam; b. means for directing said object beam at said object; c. a thermochromic film which exhibits hysteresis in changing from a first reflectance to a second reflectance with changing temperature, the reflectance hysteresis loop of said film being bounded by a maximum saturation temperature associated with its low temperature reflectance and a minimum saturation temperature associated with its high temperature reflectance, said film being located so that the infrared energy transmitted through the object impinges on the film, and the power of said beams being adequate to permit absorption of sufficient energy to rapidly cause transition from one reflectance to another within the loop; d. means for establishing said thermochromic film at a temperature between said maximum and minimum saturation temperatures; e. means for directing said reference beam onto said film, thereby to produce interference patterns on said film; and f. means for limiting the film exposure time to a period which is not appreciably greater than the ratio of the square of a given diffusion length and the film''s thermal diffusivity, wherein the diffusion length is established by the resolution which is desired to record said interference pattern.
Claim 12
Dependent Claim
35 words
The method of producing a hologram as claimed in claim 7 wherein the time of transition is less than 10 times the ratio of the square of a diffusion length and the film''s thermal diffusivity.
Claim 13
Dependent Claim
38 words
The method of producing a visible image as set forth in claim 8 wherein the time of transition is less than 10 times the ratio of the square of the diffusion length and the film'' s thermal diffusivity.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |