US3715212A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photochromic display and storage device and method of operation thereof
Assignee: RCA Corp
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Filing: 1970-12-07
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Granted: 1973-02-06
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Expires: 1990-12-07
Abstract
Abstract A photochromic display and storage element having a relatively high photochromic efficiency at temperatures above room temperature and a relatively low photochromic efficiency at room temperature consists of a substituted thioindigo dye dissolved in a heat-cured epoxy resin having a glass transition temperature of between above room temperature and 100*C. Information is placed on the element by heating it to or above the glass transition temperature and shining light of a first wavelength (write light) on the element. The image is stored by cooling the element to room temperature. In order to read the image, light of a second wavelength (read light) is passed through the element at room temperature. The image is erased with light of this second wavelength by first heating the element to or above the glass transition temperature.
Inventors
- 👤 D Ross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:01
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/72; G03C1/73; G03C5/00; G03C5/56; G11; G11C; G11C13/00; G11C13/04; G11C13/041; Y; Y10; Y10S; Y10S430/00; Y10S430/163
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
98 words
A method of operating a photochromic element comprising a photochromic indigoid dye in a polymeric host, said host having a glass transition temperature above room temperature including the steps of a. heating said element to a temperature above said glass transition temperature, b. writing an image on said heated element by irradiating the element with light of a wavelength within the absorption spectra of one photochromic state c. cooling said element to room temperature d. reading said image by irradiating said cooled element with light of a wavelength within the absorption spectra of one of the photochromic states.
Claim 2
Independent Claim
98 words
A method of operating a photochromic element comprising a photochromic indigoid dye in a polymeric host, said host having a glass transition temperature above room temperature including the steps of a. heating said element to a temperature above said glass transition temperature, b. writing an image on said heated element by irradiating the element with light of a wavelength within the absorption spectra of one photochromic state c. cooling said element to room temperature d. reading said image by irradiating said cooled element with light of a wavelength within the absorption spectra of one of the photochromic states.
Claim 3
Independent Claim
106 words
A method of operating a photochromic element comprising an indigoid dye having cis and trans isomers dissolved in a polymeric host, said host having a glass transition temperature of between room temperature and 100*C. including the steps of a. converting said element to the cis rich photostationary state b. heating said element to a temperature greater than said glass transition temperature, c. writing an image on said heated element by irradiation with light of a wavelength in the cis isomer absorption band, d. cooling said element to room temperature and then e. reading said image with light of a wavelength in the trans isomer absorption band.
Claim 4
Independent Claim
106 words
A method of operating a photochromic element comprising an indigoid dye having cis and trans isomers dissolved in a polymeric host, said host having a glass transition temperature of between room temperature and 100*C. including the steps of a. converting said element to the cis rich photostationary state b. heating said element to a temperature greater than said glass transition temperature, c. writing an image on said heated element by irradiation with light of a wavelength in the cis isomer absorption band, d. cooling said element to room temperature and then e. reading said image with light of a wavelength in the trans isomer absorption band.
Claim 5
Dependent Claim
41 words
The method described in claim 4 wherein said writing wavelength is about equivalent to the wavelength of maximum absorption of said cis isomer and wherein said reading wavelength is about equivalent to the wavelength of maximum absorption of said cis isomer.
Claim 6
Dependent Claim
25 words
A photochromic element comprising a photochromic indigoid dYe dissolved in a cross-linked polymer having a glass transition temperature between greater than room temperature and 100*C.
Claim 7
Dependent Claim
25 words
A photochromic element comprising a photochromic indigoid dYe dissolved in a cross-linked polymer having a glass transition temperature between greater than room temperature and 100*C.
Claim 8
Dependent Claim
47 words
The photochromic element described in claim 6 wherein the indigoid dye is represented by the formula wherein X and Y are atoms from the group consisting of sulfur, selenium and substituted nitrogen and R and R'' are selected from the group consisting of hydrogen and alkoxy radicals.
Claim 9
Dependent Claim
16 words
The photochromic element described in claim 5 wherein R and R'' are branched chain alkoxy radicals.
Claim 10
Dependent Claim
23 words
The photochromic element described in claim 4 wherein said polymer is a heat curable epoxy derived from glycidyl ethers of di-functional hydroxy compounds.
Claim 11
Dependent Claim
25 words
The photochromic element described in claim 4 wherein the molar concentration of dye in said polymer is from about 10 3 to 10 5 molar.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |