Patent US4202608A successfully refreshed from Google Patents.
US4202608A
Expired / Lapsed
US
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Instrument having a liquid crystal display
Assignee: US Philips Corp
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Filing: 1978-04-10
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Granted: 1980-05-13
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Expires: 1998-04-10
Abstract
Abstract An instrument having a liquid crystal display disposed behind a glass cover and separated from the cover by a hollow space. The hollow space is filled with an immersion medium to which is added a substance imparting thixotropic properties to the immersion medium. The added substance has a refractive index comparable to that of the immersion medium.
Inventors
- 👤 Meinolph Kaufmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:07
CPC Classifications
G; G04; G04G; G04G9/00; G04G9/0023; G04G9/0029; G04G9/0035; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133502
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
59 words
In an instrument having a liquid crystal display disposed behind a glass cover and separated from said glass cover by a hollow space filled with an immersion medium, the improvement comprising: said immersion medium containing a substance imparting thixotropic properties to said medium, said substance having a refractive index approximately equal to the refractive index of the immersion medium.
Claim 2
Dependent Claim
59 words
In an instrument having a liquid crystal display disposed behind a glass cover and separated from said glass cover by a hollow space filled with an immersion medium, the improvement comprising: said immersion medium containing a substance imparting thixotropic properties to said medium, said substance having a refractive index approximately equal to the refractive index of the immersion medium.
Claim 3
Dependent Claim
13 words
An instrument according to claim 1, said immersion medium comprises a silicone oil.
Claim 4
Dependent Claim
16 words
An instrument according to claim 1, wherein such immersion medium comprises paraffin oil of low viscosity.
Claim 5
Dependent Claim
16 words
An instrument according to claim 1, wherein said substance imparting thixotropic properties comprises a pyrogenic silica.
Claim 6
Dependent Claim
21 words
An instrument according to claim 4, wherein said substance imparting thixotropic comprises approximately 8% of the weight of the immersion medium.
Claim 7
Dependent Claim
16 words
An instrument according to claim 1, wherein said immersion medium comprises: a substance absorbing ultra-violet radiation.
References Cited (Backward Citations)
US4043638A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-05-13 | 1983-11-12 | 1984-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-13 | 1987-11-12 | 1988-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-13 | 1991-11-12 | 1992-05-13 | $7700.00 | Window Closed / Lapsed |