Patent US5694496A successfully refreshed from Google Patents.
US5694496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical waveplate and A method of manufacturing the optical waveplate
Assignee: NTT Inc
•
Filing: 1996-11-12
•
Granted: 1997-12-02
•
Expires: 2016-11-12
Abstract
Abstract An optical waveplate includes a polyimide with a film thickness of 20 mu m or less.
Inventors
- 👤 Shinji Ando
- 👤 Takashi Sawada
- 👤 Yasuyuki Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:16
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/12007; G02B6/12009; G02B6/12011; C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1039; G02B5/00; G02B5/30; G02B5/3083; G02B6/12023; G02B6/122; G02B6/1221; G02B6/126; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29331; G02B6/29335; G02B6/29338; G02B6/29341; G02B6/29346; G02B6/2935; G02B6/29352; G02B2006/12083; G02B2006/12116
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
67 words
A planar lightwave circuit optical waveplate comprising a polyimide film having a film thickness of not to exceed 20 μm and a birefringence equal to at least 0.031, wherein said planar lightwave circuit optical waveplate being used in connection with incident light having a wavelength of at least 1.3 μm, said planar lightwave circuit optical waveplate further maintains retardation at a temperature of at least 250° Celsius.
Claim 2
Dependent Claim
67 words
A planar lightwave circuit optical waveplate comprising a polyimide film having a film thickness of not to exceed 20 μm and a birefringence equal to at least 0.031, wherein said planar lightwave circuit optical waveplate being used in connection with incident light having a wavelength of at least 1.3 μm, said planar lightwave circuit optical waveplate further maintains retardation at a temperature of at least 250° Celsius.
Claim 3
Dependent Claim
33 words
A waveplate according to claim 1, wherein said polyimide film contains a repeating unit represented by the following formula: ##STR7## (wherein X represents a divalent organic group containing at least one benzene ring).
Claim 4
Dependent Claim
20 words
A waveplate according to claim 1, wherein said polyimide film contains a repeating unit represented by the following formula: ##STR8##
References Cited (Backward Citations)
US5121238A
Cited
EP0424951B1
Cited
EP0454590A2
Cited
JPH04175729A
Cited
JPH04241304A
Cited
JPH04288331A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-01 | 2001-06-02 | 2001-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-01 | 2005-06-02 | 2005-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-01 | 2009-06-02 | 2009-12-02 | $7700.00 | Window Closed / Lapsed |