US3829684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid crystal image converter system responsive to ionizing radiation
Assignee: Thales SA
•
Filing: 1973-04-19
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Granted: 1974-08-13
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Expires: 1993-04-19
Abstract
Abstract The invention relates to the display of visible images corresponding to patterns projected by means of ionizing agents such as X-rays, gamma -rays or particle beams. The image converter in accordance with the invention comprises: a fluorescent screen optically coupled to a photoconductive film, the latter being electrically coupled to a liquid crystal film whose dynamic scattering properties are utilised to render visible the patterns projected onto the fluorescent screen by means of the ionizing radiation.
Inventors
- 👤 E Leiba
- 👤 G Assouline
- 👤 M Hareng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:28
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/135; G21; G21K; G21K4/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
125 words
Liquid crystal image converter system for displaying a visible image in response to an image bearing beam of ionizing radiation, said system comprising: a screen of fluorescent material for collecting said beam, a photoconductor film having one face optically coupled with said screen, a liquid crystal film electrically coupled to the face of said photoconductor film opposite said one face, and electrical biasing means for applying a voltage across said films; the electrical coupling of said films allowing the transmission of a non-uniform potential distribution; said photoconductor film being photo-induced by said radiation through the medium of said screen; the voltage drop across said liquid crystal film rising above the dynamic scattering threshold of said liquid crystal within each photoinduced area of said photoconductor film.
Claim 2
Dependent Claim
125 words
Liquid crystal image converter system for displaying a visible image in response to an image bearing beam of ionizing radiation, said system comprising: a screen of fluorescent material for collecting said beam, a photoconductor film having one face optically coupled with said screen, a liquid crystal film electrically coupled to the face of said photoconductor film opposite said one face, and electrical biasing means for applying a voltage across said films; the electrical coupling of said films allowing the transmission of a non-uniform potential distribution; said photoconductor film being photo-induced by said radiation through the medium of said screen; the voltage drop across said liquid crystal film rising above the dynamic scattering threshold of said liquid crystal within each photoinduced area of said photoconductor film.
Claim 3
Dependent Claim
20 words
Image converter system as claimed in claim 1, wherein said liquid crystal film is a nematic phase liquid crystal material.
Claim 4
Dependent Claim
33 words
Image converter system as claimed in claim 1, wherein said liquid crystal film is made of a mixture of nematic and cholesteric liquid crystal materials exhibiting a persistence of the scattering state developed.
Claim 5
Dependent Claim
38 words
Image converter as claimed in claim 1, wherein said electrical biasing means comprise a pair of transparent electrodes arranged opposite one another and means for applying a voltage between said electrodes, said films being located between said electrodes.
Claim 6
Dependent Claim
50 words
Image converter system as claimed in claim 4, wherein one of said electrodes is in contact with said photoconductor film and with said screen; the other electrode being deposited upon a transparent substrate and being in contact with said liquid crystal film; said films being in contact with each other.
Claim 7
Dependent Claim
72 words
Image converter system as claimed in claim 4, wherein one of said electrodes is deposited upon a transparent substrate and has a face in contact with said liquid crystal film; the other electrode being in contact with said photoconductor film and being separated from said screen by an optical fibre plate; the fibres of said optical fibre plate being disposed perpendicularly to its faces; said films being in contact with each other.
Claim 8
Dependent Claim
36 words
Image converter system as claimed in claim 5, further comprising: a window of a material permeable to said ionizing radiation; said screen being located between said window and the electrode In contact with the photoconductor film.
Claim 9
Dependent Claim
14 words
Image converter system as claimed in claim 7, wherein said permeable material is beryllium.
Claim 10
Dependent Claim
48 words
Image converter system as claimed in claim 4, wherein said films are separated by a plate exhibiting transverse conduction and acting as an opaque screen; said transverse conduction plate being capable of transmitting from one to the other of its faces, the local values of the electrical potential.
Claim 11
Dependent Claim
36 words
Image converter system as claimed in claim 9, wherein the face of said transverse conduction plate, which is disposed towards said liquid crystal film, is coated with a mosaic of small mirrors insulated from one another.
Claim 12
Dependent Claim
20 words
Image converter system as claimed in claim 1, wherein said fluorescent screen is made of a material sensitive to X-rays.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |