US5398133A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High endurance near-infrared optical window
Assignee: Transpacific IP Ltd
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Filing: 1993-10-27
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Granted: 1995-03-14
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Expires: 2013-10-27
Abstract
Abstract Multilayers of low refractive index amorphous silicon nitride and high refractive index amorphous silicon are interleaved to construct a near-infrared optical filter. For an edge filter, the structure is transparent to near-infrared light and opaque to visible light. For a band-pass filter, the low-pass filter is superimposed with a high-pass filter. Anti-reflection coating can be added to improve the transmittance. These multilayers are deposited with Plasma Enhanced Chemical Vapor Deposition technique.
Inventors
- 👤 Rung-Ywan Tsai
- 👤 Fang-Chuan Ho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:07
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/28; G02B5/281
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
88 words
A near infrared optical filter, comprising: a substrate which is transparent to visible and near infrared light; a first set of refractive index layers composed of amorphous silicon nitride (a-SiNx:H) which is transparent to visible and near-infrared light; a second set of layers, having a refractive index greater than that of said first set of layers, composed of material which is transparent to near-infrared light but absorptive to visible light; said first set of layers and said second set of layers being interleaved and deposited over said substrate.
Claim 2
Dependent Claim
88 words
A near infrared optical filter, comprising: a substrate which is transparent to visible and near infrared light; a first set of refractive index layers composed of amorphous silicon nitride (a-SiNx:H) which is transparent to visible and near-infrared light; a second set of layers, having a refractive index greater than that of said first set of layers, composed of material which is transparent to near-infrared light but absorptive to visible light; said first set of layers and said second set of layers being interleaved and deposited over said substrate.
Claim 3
Dependent Claim
29 words
A near-infrared optical filter as described in claim 1, wherein the total number of said first set of layers and said second set of layers is less than 20.
Claim 4
Dependent Claim
26 words
A near-infrared optical filter as described in claim 1, wherein the refractive index of said amorphous silicon nitride is 1.82 at a wavelength of 500 nm.
Claim 5
Dependent Claim
22 words
A near-infrared optical filter as described in claim 3, wherein said filter is transparent to near-infrared light and opaque to visible light.
Claim 6
Dependent Claim
27 words
A near-infrared optical filter as described in claim 3, wherein the refractive index of the second set of layers is 3.62-0.3i at a wavelength of 500 nm.
Claim 7
Dependent Claim
22 words
A near-infrared optical filter as described in claim 5, wherein the high refractive index is 3.62-0.3i at a wavelength of 500 nm.
Claim 8
Dependent Claim
14 words
A near-infrared optical filter as described in claim 3, wherein said substrate is quartz.
Claim 9
Dependent Claim
20 words
A near-infrared optical filter as described in claim 3, wherein said first set of layers are deposited with PECVD technique.
Claim 10
Dependent Claim
20 words
A near-infrared optical filter as described in claim 3, wherein said second set of layers are deposited with PECVD technique.
Claim 11
Dependent Claim
37 words
A near-infrared optical filter as described in claim 3, wherein an anti-reflection film is coated on the side of the substrate opposite to where said first set of layers and said second set of layers are interleaved.
Claim 12
Dependent Claim
18 words
A near-infrared optical filter as described in claim 3, wherein said anti-reflection film is transparent to near-infrared light.
Claim 13
Dependent Claim
35 words
A near-infrared optical filter as described in claim 3, wherein a second near-infrared filter of similar structure as said filter is attached by glueing the substrate of the second near-infrared filter back-to-back with said substrate.
Claim 14
Dependent Claim
17 words
A near-infrared optical filter as described in claim 3, wherein said filter is a narrow band-pass filter.
Claim 15
Dependent Claim
53 words
A near-infrared optical filter as described in claim 3, wherein said first set of layers and said second set of layers are deposited on both sides of said substrate, the layers on one side of the substrate forming a low-pass filter, the layers on second side of the substrate forming a high-pass filter.
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) | 1998-03-13 | 1998-09-12 | 1999-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-03-13 | 2002-09-12 | 2003-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-03-13 | 2006-09-12 | 2007-03-14 | $7700.00 | Window Closed / Lapsed |