US4826267A
Expired / Lapsed
US
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Spectral filter with integral antireflection coating
Assignee: Teledyne Scientific and Imaging LLC
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Filing: 1987-11-30
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Granted: 1989-05-02
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Expires: 2007-11-30
Abstract
Abstract A gradient index filter can be fabricated with integral antireflection properties without degrading the inband performance of the filter. The filter is for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band. The filter includes an antireflecting portion having a nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy from a theoretical interface between a first medium having a first predetermined refractive index and a second medium having a second predetermined refractive index. A band rejecting portion has a periodic refractive index profile whose periodicity and amplitude are selected to reflect a maximum amount of electromagnetic energy within the relfection band. At least part of the nominal refractive index profile is modulated by the superposition thereon of at least part of the periodic refractive index profile. The entire periodic refractive index profile maybe superimposed on the monial refractive index profile, while the periodic refractive index profile may be a rugate profile. In addition, the nominal incident and substrate refractive index profiles may be quintic refractive index profiles.
Inventors
- 👤 Randolph L. Hall
- 👤 Frank J. Woodberry
- 👤 William H. Southwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:50
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/28; G02B5/285; G02B1/00; G02B1/10; G02B1/11; G02B1/113; G02B5/289
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
113 words
A gradient index spectral filter for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band, comprising: an antireflecting portion having a nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy; and a band rejecting portion having a periodic refractive index profile whose periodicity and amplitude are selected to reflect a maximum amount of electromagnetic energy within the reflection band, at least part of the nominal refractive index profile being modulated by the superposition thereon of at least part of the periodic refractive index profile.
Claim 2
Dependent Claim
113 words
A gradient index spectral filter for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band, comprising: an antireflecting portion having a nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy; and a band rejecting portion having a periodic refractive index profile whose periodicity and amplitude are selected to reflect a maximum amount of electromagnetic energy within the reflection band, at least part of the nominal refractive index profile being modulated by the superposition thereon of at least part of the periodic refractive index profile.
Claim 3
Dependent Claim
20 words
The filter of claim 1, wherein the entire periodic refractive index profile is superimposed on the nominal refractive index profile.
Claim 4
Dependent Claim
16 words
The filter of claim 1, wherein the periodic refractive index profile further comprises a rugate profile.
Claim 5
Dependent Claim
46 words
The filter of claim 1, wherein the antireflecting portion further comprises an incident antireflecting portion disposed adjacent to the incident medium, the nominal refractive index profile being selected to reflect a minimum amount of electromagnetic energy from the interface between the incident medium and the filter.
Claim 6
Dependent Claim
68 words
The filter of claim 4, further comprising a substrate antireflecting portion disposed adjacent to the substrate and having a substrate nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy from the interface between the filter and the substrate, at least part of the substrate nominal refractice index profile being modulated by the superposition thereon of at least part of the periodic refractive index profile.
Claim 7
Dependent Claim
23 words
The filter of claim 5, wherein the entire periodic refractive index profile is superimposed on the incident and substrate nominal refractive index profiles.
Claim 8
Dependent Claim
44 words
The filter of claim 1, wherein the antireflecting portion further comprises a substrate antireflecting portion disposed adjacent to the substrate, the nominal refractive index profile being selected to reflect a minimum amount of electromagnetic energy from the interface between the filter and the substrate.
Claim 9
Dependent Claim
70 words
The filter of claim 7, further comprising an incident antireflecting portion disposed adjacent to the incident medium and having an incident nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy from the interface between the filter and the incident medium, at least part of the incident nominal refractive index profile being modulated by the superposition thereon of at least part of the periodic refractive index profile.
Claim 10
Dependent Claim
23 words
The filter of claim 8, wherein the entire periodic refractive index profile is superimposed on the incident and substrate nominal refractive index profiles.
Claim 11
Independent Claim
118 words
A method of making a gradient index spectral filter for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band, comprising the steps of: selecting a periodicity and amplitude for a periodic refractive index profile which will reflect a maximum amount of electromagnetic energy within the reflection band; selecting an antireflecting portion with a nominal refractive index profile which will reflect a minimum amount of electromagnetic energy; and fabricating the filter such that at least part of the periodic refractive index profile is superimposed on at least part of the nominal refractive index profile.
Claim 12
Independent Claim
118 words
A method of making a gradient index spectral filter for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band, comprising the steps of: selecting a periodicity and amplitude for a periodic refractive index profile which will reflect a maximum amount of electromagnetic energy within the reflection band; selecting an antireflecting portion with a nominal refractive index profile which will reflect a minimum amount of electromagnetic energy; and fabricating the filter such that at least part of the periodic refractive index profile is superimposed on at least part of the nominal refractive index profile.
Claim 13
Dependent Claim
28 words
The method of claim 10, wherein the step of selecting a periodicity and amplitude further comprises: selecting a sinewave periodicity and amplitude for a rugate refractive index profile.
Claim 14
Dependent Claim
29 words
The method of claim 10, wherein the step of superimposing further comprises superimposing the entire periodic refractive index profile on at least part of the nominal refractive index profile.
Claim 15
Dependent Claim
112 words
The method of claim 10, wherein the step of selecting an antireflecting portion further comprises: selecting an incident antireflecting portion with an incident nominal refractive index profile which will reflect a minimum amount of electromagnetic energy from the interface between the incident medium and the filter; further comprising the step of: selecting a substrate antireflecting portion with a substrate nominal refractive index profile which will reflect a minimum amount of electromagnetic energy from the interface between the substrate and the filter; and wherein the step of superimposing further comprises: superimposing at least part of the periodic refractive index profile on at least part of the incident and substrate nominal refractive index profiles.
Claim 16
Dependent Claim
32 words
The method of claim 13, wherein the step of superimposing further comprises superimposing the entire periodic refractive index profile on at least part of the incident and substrate nominal refractive index profiles.
Claim 17
Dependent Claim
112 words
The method of claim 10, wherein the step of selecting an antireflecting portion further comprises: selecting a substrate antireflecting portion with a substrate nominal refractive index profile which will reflect a minimum amount of electromagnetic energy from the interface between the substrate and the filter; further comprising the step of: selecting an incident antireflecting portion with an incident nominal refractive index profile which will reflect a minimum amount of electromagnetic energy from the interface between the incident medium and the filter; and wherein the step of superimposing further comprises: superimposing at least part of the periodic refractive index profile on at least part of the incident and substrate nominal refractive index profiles.
Claim 18
Dependent Claim
32 words
The method of claim 15, wherein the step of superimposing further comprises superimposing the entire periodic refractive index profile on at least part of the incident and substrate nominal refractive index profiles.
Claim 19
Dependent Claim
150 words
A gradient index spectral filter for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band, comprising: an incident antireflecting portion disposed adjacent to the incident medium and having a nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy from the interface between the incident medium and the filter; and a substrate antireflecting portion disposed between the substrate and the incident portion and having a nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy from the interface between the filter and the substrate, the nominal incident and substrate refractive index profiles being modulated by a superimposed periodic refractive index profile whose periodicity and amplitude are selected to reflect a maximum amount of electromagnetic energy within the reflection band.
Claim 20
Dependent Claim
150 words
A gradient index spectral filter for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band, comprising: an incident antireflecting portion disposed adjacent to the incident medium and having a nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy from the interface between the incident medium and the filter; and a substrate antireflecting portion disposed between the substrate and the incident portion and having a nominal refractive index profile selected to reflect a minimum amount of electromagnetic energy from the interface between the filter and the substrate, the nominal incident and substrate refractive index profiles being modulated by a superimposed periodic refractive index profile whose periodicity and amplitude are selected to reflect a maximum amount of electromagnetic energy within the reflection band.
Claim 21
Dependent Claim
16 words
The filter of claim 17, wherein the periodic refractive index profile further comprises a rugate profile.
Claim 22
Dependent Claim
20 words
The filter of claim 17, wherein the nominal incident and substrate refractive index profiles further comprise quintic refractive index profiles.
Claim 23
Independent Claim
152 words
A method of making a gradient index spectral filter for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band, comprising the steps of: selecting a periodicity and amplitude for a periodic refractive index profile which will reflect a maximum amount of electromagnetic energy within the reflection band; selecting an incident antireflecting portion with a refractive index profile which will reflect a minimum amount of electromagnetic energy from the interface between the incident medium and the filter; selecting a substrate antireflecting portion with a refractive index profile which will reflect a minimum amount of electromagnetic energy from the interface between the filter and the substrate; combining the incident profile and the substrate profile; and fabricating the filter such that the periodic profile is superimposed on the combined profile.
Claim 24
Independent Claim
152 words
A method of making a gradient index spectral filter for placement between an incident medium and a substrate to reflect incident electromagnetic energy having wavelengths within a predetermined band of wavelengths and to transmit incident electromagnetic energy having wavelengths outside of the reflection band, comprising the steps of: selecting a periodicity and amplitude for a periodic refractive index profile which will reflect a maximum amount of electromagnetic energy within the reflection band; selecting an incident antireflecting portion with a refractive index profile which will reflect a minimum amount of electromagnetic energy from the interface between the incident medium and the filter; selecting a substrate antireflecting portion with a refractive index profile which will reflect a minimum amount of electromagnetic energy from the interface between the filter and the substrate; combining the incident profile and the substrate profile; and fabricating the filter such that the periodic profile is superimposed on the combined profile.
Claim 25
Dependent Claim
28 words
The method of claim 20, wherein the step of selecting a periodicity and amplitude further comprises: selecting a sinewave periodicity and amplitude for a rugate refractive index profile.
Claim 26
Dependent Claim
50 words
The method of claim 20, wherein the step of selecting an incident antireflecting portion further comprises: selecting an incident antireflecting portion with a quintic refractive index profile; and wherein the step of selecting a substrate antireflecting portion further comprises; selecting a substrate antireflecting portion with a quintic refractive index profile.
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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) | 1992-05-01 | 1992-10-31 | 1993-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-01 | 1996-10-31 | 1997-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-01 | 2000-10-31 | 2001-05-02 | $7700.00 | Window Closed / Lapsed |