US3584934A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nonmechanical shutter
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1968-04-12
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Granted: 1971-06-15
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Expires: 1988-04-12
Abstract
Abstract This invention relates to a nonmechanical shutter for a camera or similar device. The shutter is comprised of a transparent substrate, the color form of a compound which is thermally rendered colorless and the colorless form of a compound which is thermally rendered colored. The change of the colored compound to colorless form occurs prior to the change of colorless compound to colored form with the lapse of a finite period of time between these color changes. During this time period, the shutter is substantially light transparent, i.e. the shutter is in the open position. Thus when used in a camera, heating of the shutter renders the shutter transparent and permits exposure of the photosensitive medium of the camera. The time of exposure is determined by the combination of thermochromic substances in the shutter. The shutter is ''''cocked'''' after use by allowing the thermochromic change to reverse itself, or, when the thermochromic substances are also photochromic, by exposure to light which reverses the thermochromic color change, e.g. ultraviolet and visible light.
Inventors
- 👤 Hollis E French
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:14
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/08
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
107 words
A nonmechanical shutter comprising a transparent substrate having thereon a layer containing a first reversible thermochromic compound in its opaque colored form, and also having thereon a layer containing a second reversible thermochromic compound in its transparent colorless form, said second thermochromic compound extending over the same substrate region covered by said first thermochromic compound, said shutter also having heating means disposed to heat said thermochromic compounds, the reversible change of said colored thermochromic compound to its colorless transparent form occurring prior, by a finite period, to the reversible change of said colorless thermochromic compound to its colored opaque form in response to the application of heat.
Claim 2
Dependent Claim
107 words
A nonmechanical shutter comprising a transparent substrate having thereon a layer containing a first reversible thermochromic compound in its opaque colored form, and also having thereon a layer containing a second reversible thermochromic compound in its transparent colorless form, said second thermochromic compound extending over the same substrate region covered by said first thermochromic compound, said shutter also having heating means disposed to heat said thermochromic compounds, the reversible change of said colored thermochromic compound to its colorless transparent form occurring prior, by a finite period, to the reversible change of said colorless thermochromic compound to its colored opaque form in response to the application of heat.
Claim 3
Dependent Claim
15 words
A nonmechanical shutter of claim 1 wherein both of said thermochromic compounds are also photochromic.
Claim 4
Dependent Claim
17 words
A nonmechanical shutter of claim 2 including radiation means for supplying said photochromic compounds with activating radiation.
Claim 5
Dependent Claim
23 words
A nonmechanical shutter of claim 3 wherein said radiation means includes both a source of ultraviolet light and a source of visible light.
Claim 6
Dependent Claim
18 words
A nonmechanical shutter of claim 4 wherein said thermochromic compounds have the same color in their colored form.
Claim 7
Dependent Claim
25 words
A nonmechanical shutter of claim 1 comprising a plurality of shutters, the shutters being arranged on a nonlight-transmissive support therefor to permit successive use thereof.
Claim 8
Dependent Claim
13 words
A nonmechanical shutter of claim 6 wherein said thermochromic compounds are also photochromic.
Claim 9
Dependent Claim
17 words
A nonmechanical shutter of claim 7 including radiation means for supplying activating radiation to said photochromic compounds.
Claim 10
Dependent Claim
22 words
A nonmechanical shutter of claim 8 wherein said radiation means includes a source of ultraviolet light and a source of visible light.
Claim 11
Dependent Claim
15 words
A nonmechanical shutter of claim 5 wherein said heating means comprises a source of microwaves.
Claim 12
Dependent Claim
17 words
A nonmechanical shutter of claim 5 wherein said heating means comprises a source of radio frequency radiation.
Claim 13
Dependent Claim
16 words
A nonmechanical shutter of claim 5 wherein said heating means comprises a source of hot fluid.
Claim 14
Dependent Claim
25 words
A nonmechanical shutter of claim 5 wherein said colorless thermochromic compound comprises a normally colored photochromic compound bleached to its colorless form with visible light.
Claim 15
Dependent Claim
25 words
A nonmechanical shutter of claim 13 wherein said colored thermochromic compound comprises a normally colorless photochromic compound converted to its colored form by ultraviolet irradiation.
Claim 16
Dependent Claim
23 words
A nonmechanical shutter of claim 13 wherein said colorless thermochromic compound comprises a photochromic spiropyran bleached to its colorless form with visible light.
Claim 17
Dependent Claim
25 words
A nonmechanical shutter of claim 14 wherein said colored thermochromic compound comprises a normally colorless photochromic spiropyran converted to its colored form by ultraviolet irradiation.
Claim 18
Dependent Claim
13 words
A nonmechanical shutter of claim 15 wherein said spiropyran comprises 1, 3, 3-trimethylindolinodinitrobenzopyrylospiran.
Claim 19
Dependent Claim
13 words
A nonmechanical shutter of claim 16 wherein said sPiropyran comprises 1, 3, 3-trimethylindolinobenzopyrylospiran.
Claim 20
Dependent Claim
14 words
A nonmechanical shutter of claim 15 wherein said spiropyran comprises 1, 3, 3-trimethylindolino-6'', 8''-dinitrobenzopyrylospiran.
Claim 21
Dependent Claim
14 words
A nonmechanical shutter of claim 15 wherein the spiropyran is 1, 3, 3-trimethyl-5-chloroindolino-6'', 8''-dinitrobenzopyrylospiran.
Claim 22
Dependent Claim
13 words
A nonmechanical shutter of claim 16 wherein said spiropyran comprises 1, 3, 3-trimethylindolino-8''-nitrobenzopyrylospiran.
Claim 23
Dependent Claim
13 words
A nonmechanical shutter of claim 16 wherein said spiropyran comprises 1, 3, 3,-trimethylindolino-6''-nitrobenzopyrylospiran.
Claim 24
Dependent Claim
13 words
A nonmechanical shutter of claim 16 wherein said spiropyran comprises 5-chlor-1, 3, 3-trimethylindolino-6''-nitrobenzopyrylospiran.
Claim 25
Dependent Claim
12 words
A nonmechanical shutter of claim 15 wherein said spiropyran comprises a benzopyrylinobenzopyrylospiran.
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) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |