US5016985A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared filter using cholesteric liquids
Assignee: Rockwell Collins ElectroMechanical Systems Inc
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Filing: 1988-06-24
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Granted: 1991-05-21
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Expires: 2008-06-24
Abstract
Abstract A high precision optical filter includes a wideband filter element and a cholesteric liquid crystal notch filter element. In one embodiment, a wideband infrared filter blocks infrared wavelengths beginning at a nearly visible corner wavelength and a cholesteric liquid crystal filter blocks transmission of infrared wavelengths in a precise narrow band that includes the corner wavelength and that extends down to visible wavelengths. The liquid crystal filter may include a polymer for maintaining maximum reflectivity of the filter near the corner wavelength over an anticipated operating temperature range. The combined optical filter may be fabricated by depositing a matched pair of liquid crystal cholesteric films on a glass infrared filter element. In another embodiment, an optical filter according to the invention forms an eyepiece in a night vision goggles assembly for blocking visible light. The filter may also be mounted on a display device to block the transmission of undesirable infrared emissions at the source.
Inventors
- 👤 Michael Kalmanash
- 👤 Arthur L. Berman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:47
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/28; G02B5/281; G02B5/282; C; C09; C09K; C09K19/00; C09K19/04; C09K19/06; C09K19/08; C09K19/10; C09K19/22; C09K19/36; G02B5/30; G02B5/3016
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
29 words
A high precision wideband optical filter system comprising: a wideband optical filter having a corner wavelength; and a cholesteric liquid crystal notch filter, said notch including said corner wavelength.
Claim 2
Dependent Claim
29 words
A high precision wideband optical filter system comprising: a wideband optical filter having a corner wavelength; and a cholesteric liquid crystal notch filter, said notch including said corner wavelength.
Claim 3
Dependent Claim
22 words
The optical filter of claim 1 and wherein said liquid crystal filter comprises at least two films disposed on said wideband filter.
Claim 4
Dependent Claim
25 words
The filter of claim 1 and wherein said liquid crystal filter contains cholesteric and nematic liquid crystals in a ratio of approximately 70:30 by weight.
Claim 5
Dependent Claim
24 words
The filter of claim 1 and wherein said cholesteric liquid crystal filter includes a nematic material for substantially determining the width of said notch.
Claim 6
Dependent Claim
58 words
The filter of claim 1 wherein said notch filter further comprises: a first cholesteric liquid crystal having a reflective band for reflecting right-handed circularly polarized incident radiation; and a second cholesteric liquid crystal having a reflective band for reflecting left-handed circularly polarized incident radiation, each liquid crystal having its respective reflective band substantially centered on said corner wavelength.
Claim 7
Dependent Claim
50 words
An infrared optical filter comprising: an infrared filter for blocking transmission of light over a wide infrared band, said infrared filter having a nearly visible corner wavelength; and a cholesteric liquid crystal filter for blocking transmission of infrared light in a narrow band, said narrow band including said corner wavelength.
Claim 8
Dependent Claim
50 words
An infrared optical filter comprising: an infrared filter for blocking transmission of light over a wide infrared band, said infrared filter having a nearly visible corner wavelength; and a cholesteric liquid crystal filter for blocking transmission of infrared light in a narrow band, said narrow band including said corner wavelength.
Claim 9
Dependent Claim
34 words
The filter of claim 1, 2 or 6, and wherein said liquid crystal filter includes a polymer for maintaining the maximum reflectivity of said filter near a constant wavelength over an operating temperature range.
Claim 10
Dependent Claim
31 words
The filter of claim 6 and wherein said liquid crystal filter includes an amount of nematic material chosen to maximize the reflectivity of said cholesteric filter substantially at said corner wavelength.
Claim 11
Dependent Claim
19 words
The filter of claim 6 and wherein said cholesteric filter comprises two polymer films deposited on said infrared filter.
Claim 12
Dependent Claim
38 words
A night vision goggles assembly comprising: a goggles frame; and an eyepiece mounted in said frame, said eyepiece including a visible light filter element and a cholesteric liquid crystal filter element disposed on said visible light filter element.
Claim 13
Dependent Claim
38 words
A night vision goggles assembly comprising: a goggles frame; and an eyepiece mounted in said frame, said eyepiece including a visible light filter element and a cholesteric liquid crystal filter element disposed on said visible light filter element.
Claim 14
Dependent Claim
29 words
An eyepiece including: a supporting optical element forming a wideband filter element; at least two cholesteric liquid crystal films, forming a notch filter, disposed on the supporting optical element.
Claim 15
Dependent Claim
29 words
An eyepiece including: a supporting optical element forming a wideband filter element; at least two cholesteric liquid crystal films, forming a notch filter, disposed on the supporting optical element.
Claim 16
Dependent Claim
69 words
A high precision, wideband optical filter system for filtering radiation from a source emitting both visible and infrared radiation, the infrared radiation including a near visible infrared radiation peak, comprising: a wideband, infrared filter having a corner wavelength between a maximum visible radiation peak from the source and the near infrared peak; and notch filter means, including a cholesteric filter element, having a notch which includes said corner wavelength.
Claim 17
Dependent Claim
69 words
A high precision, wideband optical filter system for filtering radiation from a source emitting both visible and infrared radiation, the infrared radiation including a near visible infrared radiation peak, comprising: a wideband, infrared filter having a corner wavelength between a maximum visible radiation peak from the source and the near infrared peak; and notch filter means, including a cholesteric filter element, having a notch which includes said corner wavelength.
Claim 18
Independent Claim
66 words
A method of blocking the transmission of infrared light while transmitting visible light including the steps of: providing a first infrared filter element: blocking infrared radiation above a nearly visible infrared corner wavelength with said first infrared filter element; providing a second cholesteric liquid crystal filter element; and blocking infrared radiation in a band including said nearly visible corner wavelength using said cholesteric liquid crystal element.
Claim 19
Independent Claim
66 words
A method of blocking the transmission of infrared light while transmitting visible light including the steps of: providing a first infrared filter element: blocking infrared radiation above a nearly visible infrared corner wavelength with said first infrared filter element; providing a second cholesteric liquid crystal filter element; and blocking infrared radiation in a band including said nearly visible corner wavelength using said cholesteric liquid crystal element.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-05-20 | 1994-11-19 | 1995-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-20 | 1998-11-19 | 1999-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-20 | 2002-11-19 | 2003-05-21 | $7700.00 | Window Closed / Lapsed |