Multi-spectral filter

• US 5,164,858 A
• Filed: 07/11/1991
• Issued: 11/17/1992
• Est. Priority Date: 03/07/1990
• Status: Expired due to Term

• Current Assignee: Deposition Sciences Incorporated (Martin Marietta Corporation)
• Original Assignee: Deposition Sciences Incorporated (Martin Marietta Corporation)
• Inventors: Bartolomei, Leroy A., Robbins, William M., Shimshock, Richard P., Aguilera, John A. Jr.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/728,724
• Time in Patent Office: 495 Days
• Field of Search: 359/587, 359/589, 359/590, 359/568, 359/576, 250/226
• US Class Current: 359/587
• CPC Class Codes: G01J 2003/2806 Array and filter array
• CPC Class Codes: G01J 2003/516 with several stacked filters or stacked filter-detector pairs
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361

Abstract

An optical thin film filter for the spatial and spectral separation of two or more transmitting bands of radiant energy. For a two band filter the filter has a substrate substantially transparent to radiant energy in the transmitted bands. On one surface of said substrate is a multilayer interference coating that transmits both wavelength bands of interest. On the other surface of said substrate (or on the same surface) are two sets of non-overlapping butted, parallel stripes with one set being alternately interspersed with the other. The widths of said stripes are varied to provide for precisely defined regions of spatial and spectral delineation. One set of stripes is capable of transmitting one of the bands of interest and reflecting all others, while the second set of stripes is capable of transmitting at least one band different from the one band transmitted by said first set of stripes and reflecting all others. Each of the stripes in itself is a multilayer interference coating formed of a plurality of high and low index of refraction materials.

Claims

1. An optical thin film filter for the spatial and spectral separation of two or more transmitting bands of radiant energy which comprises a first coating capable of transmitting at least two wavelength bands of interest in combination with at least a second coating capable of reflecting or absorbing one or more wavelength bands of radiant energy transmitted by said first coating, wherein at least one of said first and second coatings comprises a dielectric material and wherein said optical thin film filter further comprises

a substrate having at least one surface for receiving coatings and which is substantially transparent to said radiant energy at the wavelength bands of interest wherein said first coating is applied to one surface of said substrate;

a first photolithographic patterned coating capable of reflecting all but one wavelength band of radiant energy transmitted by said first coating; and

,

a second photolithographic patterned coating which is capable of transmitting at least one wavelength band transmitted by said first coating and capable of transmitting at least one wavelength band different than the wavelength band transmitted by said first photolithographic patterned coating, said second photolithographic patterned coating reflecting all other wavelength bands;

wherein said first and second photolithographic patterned coatings are provided on a second surface of said substrate, opposite to said first coating, in discrete, abutting and non-overlapping regions.

2. The optical thin film filter of claim 1 wherein said first and second photolithographic patterned coatings are formed of a plurality of high and low index of refraction dielectric materials, arranged in multiple layers.

3. The optical thin film filter of claim 2 wherein said first and second photolithographic patterned coatings are characterized by additional optical impedance matching layers, closest to said substrate surface, which will match the index of refraction of the lower layers of said first and second photolithographic patterned coatings to the index of refraction of said substrate.

4. The optical thin film filter of claim 2 wherein said first and second photolithographic coatings are characterized by additional optical impedance matching layers, furthest from said substrate surface, which will match the index of refraction of the upper layers of said first and second photolithographic patterned coatings to the index of refraction of the atmosphere in which the optical thin film filter is to be used.

5. The optical thin film filter of claim 1 wherein the photolithographic patterns of the first and second photolithographic patterned coatings are parallel stripes.

6. The optical thin film filter of claim 1 wherein said first photolithographic patterned coating acts as a short wavelength reflective coating, and said second photolithographic patterned coating acts as a long wavelength reflective coating.

7. An optical thin film filter for the spatial and spectral separation of two or more transmitting bands of radiant energy which comprises:

a. a substrate having at least one surface for receiving coatings and which is substantially transparent to said radiant energy at the wavelength bands of interest;

b. a first coating on one surface of said substrate, said first coating capable of transmitting two or more wavelength bands of interest and reflecting or absorbing all other out of band wavelengths;

c. a first photolithographic patterned coating capable of reflecting all but one wavelength band of radiant energy transmitted by said first coating; and

,

d. a second photolithographic patterned least one wavelength band transmitted by said first coating and capable of transmitting at least one wavelength band different than the wavelength band transmitted by said first photolithographic patterned coating, said second photolithographic patterned coating reflecting all other wavelength bands;

whereby said first and second photolithographic patterned coatings are provided on the same surface of the substrate as said first coating, in discrete abutting and non-overlapping regions, and wherein said first coating (b) is provided directly on top of the first and second photolithographic patterned coatings.

8. The optical thin film filter of claim 7 wherein the first and second photolithographic patterned coatings are formed of a plurality of high and low index of refraction dielectric materials, arranged in multiple layers.

9. The optical thin film filter of claim 8 wherein said first and second photolithographic coatings are characterized by additional optical impedance matching layers, closest to said substrate surface, which will match the index of refraction of the lower layers of said first and second photolithographic patterned coatings to the index of refraction of said substrate.

10. The optical thin film filter of claim 8 wherein said first and second photolithographic coatings are characterized by additional optical impedance matching layers, furthest from said substrate surface, which will match the index of refraction of the upper layers of said first and second photolithographic patterned coatings to the index of refraction of said first coating.

11. The optical thin film filter of claim 7 wherein said photolithographic patterns of said patterned coatings are parallel stripes.

12. The optical thin film filter of claim 7 wherein said first photolithographic patterned coating acts as a short wavelength reflective coating, and said second photolithographic patterned coating acts as a long wavelength reflective coating.

13. An optical thin film filter for the spatial and spectral separation of two or more transmitting bands of radiant energy which comprises:

a. a substrate having at least one surface for receiving coatings and which is substantially transparent to said radiant energy at the wavelength bands of interest;

b. a first coating on one surface of said substrate, said first coating capable of transmitting at least two wavelength bands of interest and reflecting or absorbing all other out of band wavelengths;

c. a first photolithographic patterned coating capable of reflecting all but one wavelength band of radiant energy transmitted by said first coating, and capable of modifying its transmission band; and

,

d. a second photolithographic patterned coating which is capable of transmitting at least one wavelength band transmitted by said first coating and capable of transmitting at least one wavelength band different than the band transmitted by said first photolithographic patterned coating while reflecting all other wavelength bands, said second photolithographic patterned coating also capable of modifying its transmission band,

whereby said first and second photolithographic patterned coatings are provided on a second surface of said substrate, opposite to said first coating, in discrete, abutting and non-overlapping regions.

14. The optical thin film filter of claim 13 wherein said first and second photolithographic patterned coatings are formed of a plurality of high and low index of refraction dielectric materials, arranged in multiple layers.

15. The optical thin film filter of claim 14 wherein said first and second photolithographic patterned coatings are characterized by additional optical impedance matching layers, closest to the surface of said substrate, which will match the index of refraction of the lower layers of said first and second photolithographic patterned coatings to the index of refraction of said substrate.

16. The optical thin film filter of claim 14 wherein said first and second photolithographic coatings are characterized by additional optical impedance matching layers, furthest from the surface of said substrate, which will match the index of refraction of the upper layers of said first and second photolithographic patterned coatings to the index of refraction of the atmosphere in which the optical thin film filter is to be used.

17. The optical thin film filter of claim 13 wherein said photolithographic patterns of said coatings are parallel stripes.

18. The optical thin film filter of claim 13 wherein said first photolithographic patterned coating acts as a short wavelength reflective coating, and said second photolithographic patterned coating acts as a long wavelength reflective coating.

19. An optical thin film filter for the spatial and spectral separation of two or more transmitting bands of radiant energy which comprises:

a. a substrate having at least one surface for receiving coatings and which is substantially transparent to said radiant energy at the wavelength bands of interest;

b. a first coating on one surface of said substrate, said first coating capable of transmitting at least two wavelength bands of interest and reflecting or absorbing all other out of band wavelengths;

c. a first photolithographic patterned coating capable of reflecting all but one wavelength band of radiant energy transmitted by said first coating, and capable of modifying its transmission band; and

,

d. a second photolithographic patterned coating which is capable of transmitting at least one wavelength band transmitted by said first coating and capable of transmitting at least one wavelength band different than the wavelength band transmitted by said first photolithographic patterned coating while reflecting all other wavelength bands, said second lithographic patterned coating also capable of modifying its transmission band;

whereby said first and second photolithographic patterned coatings are provided on the same surface of the substrate as said first coating, in discrete abutting and non-overlapping regions, and wherein said first coating is provided directly on top of the first and second photolithographic patterned coatings.

20. The optical thin film filter of claim 19 wherein said first and second photolithographic patterned coatings are formed of a plurality of high and low index of refraction dielectric materials, arranged in multiple layers.

21. The optical thin film filter of claim 20 wherein said first and second photolithographic coatings are characterized by additional optical impedance matching layers, closest to said substrate surface, which will match the index of refraction of the lower layers of said first and second photolithographic patterned coatings to the index of refraction of said substrate.

22. The optical thin film filter of claim 20 wherein said first and second photolithographic coatings are characterized by additional optical impedance matching layers, furthest from said substrate surface, which will match the index of refraction of the upper layers of said first and second photolithographic patterned coatings to the index of refraction of said first coating.

23. The optical thin film filter of claim 19 wherein said photolithographic patterns of said patterned coatings are parallel stripes.

24. The optical thin film filter of claim 19 wherein said first photolithographic patterned coating acts as a short wavelength reflective coating, and said second photolithographic patterned coating acts as a long wavelength reflective coating.

25. An optical thin film filter for the spatial and spectral separation of two or more transmitting bands of radiant energy which comprises:

a. a substrate having at least one surface for receiving coatings and which is substantially transparent to said radiant energy at the wavelength bands of interest;

b. a first coating on one surface of said substrate, said first coating capable of transmitting at least two wavelength bands of interest and reflecting or absorbing all other out of band wavelengths, said first coating acting as a wide band transmitting coating with short wavelength and long wavelength edges of said transmission band being one edge of two distinct and different colors;

c. a first photolithographic patterned coating capable of reflecting all but one wavelength band of radiant energy transmitted by said first coating, said first photolithographic coating providing the second transmission edge for one color; and

,

d. a second photolithographic patterned coating which is capable of transmitting at least one wavelength band transmitted by said first coating and capable of transmitting at least one band different than the wavelength band transmitted by said first photolithographic patterned coating, said second photolithographic patterned coating reflecting all other bands, said second photolithographic coating providing the second transmission edge for the second color bracketed by the first coating;

whereby said first and second photolithographic patterned coatings are provided on a second surface of said substrate, opposite to said first coating, in discrete, abutting and non-overlapping regions.

26. The optical thin film filter of claim 25 wherein said first and second photolithographic patterned coatings are formed of a plurality of high and low index of refraction dielectric materials, arranged in multiple layers.

27. The optical thin film filter of claim 26 wherein said first and second photolithographic coatings are characterized by additional optical impedance matching layers wherein the layers closest to the surface of said substrate match the index of refraction of said substrate.

28. The optical thin film filter of claim 26 wherein said first and second photolithographic coatings are characterized by additional optical impedance matching layers wherein the layers furthest from the surface of said substrate match the index of refraction of the atmosphere in which the optical thin film filter is to be used.

29. The optical thin film filter of claim 25 wherein said photolithographic patterns of said patterned coatings are parallel stripes.

30. The optical thin film filter of claim 25 wherein said first photolithographic patterned coating acts as a short wavelength reflective coating, and said second photolithographic patterned coating acts as a long wavelength reflective coating.

31. An optical filter system for the spatial and spectral separation of two or more transmitting bands of radiant energy which comprises:

a. a substrate having at least one surface for receiving coatings and which is substantially transparent to said radiant energy at the wavelength bands of interest;

b. a multispectral coating on one surface of said substrate, said multispectral coating capable of transmitting two or more wavelength bands of interest and reflecting or absorbing all other out of band wavelengths; and

,

c. two or more switch coatings, which provide suitable transmission of one wavelength band of interest, which wavelength band is different than that transmitted by the other switch coatings, while blocking the transmission of all other wavelength bands, said switch coatings fabricated from patterned dyed materials, wherein said switch coatings may be coated upon the multispectral coating-receiving substrate, or upon a second substrate wherein at least one of said coatings comprises a dielectric material.