Broad band pass filter including metal layers and dielectric layers of alternating refractive index
First Claim
1. An optical interference filter for a substrate, comprising:
- ten layers, said layers designated the first through the tenth in consecutive numerical order beginning with the layer furthest from the substrate;
said first layer of a material having a low refractive index and having an optical thickness of about one-eighth wavelength at a first wavelength in the near-infrared spectral region;
said second and tenth layers of a material having a high refractive index and having an optical thickness of about one-quarter wavelength at said first wavelength;
said third and ninth layers of a material having a low refractive index and having an optical thickness between one-quarter and one eighth wavelength at said first wavelength;
said fourth and eighth layers of a material having a high refractive index and having an optical thickness of less than one-quarter wavelength at a second wavelength in the visible spectrum;
said fifth and seventh layers being metal layers and having a thickness between about 12.5 and 30.0 nanometers;
said sixth layer of a material having a high refractive index and having an optical thickness less than one-half wavelength at said second wavelength;
said first wavelength being between about 800 and 1250 nanometers and said second wavelength being between about 480 and 560 nanometers; and
said high refractive index being between about 1.65 and 2.65 at a wavelength of about 520 nm and said low refractive index being between about 1.35 and 1.65 at a wavelength of about 520 nm.
2 Assignments
0 Petitions
Accused Products
Abstract
A visible light transmitting, near-infrared reflecting filter for a substrate, comprises a central group of layers (26) including two metal layers (32 and 36) separated by a spacer-layer (34) and bounded by admittance-matching layers (32 and 38). The spacer-layer has an optical thickness of less than one-half wavelength of visible light and the admittance-matching layers have an optical thickness of less than one-quarter wavelength of visible light. On each side of the central group is a group of layers (24 and 28) for boosting near infrared reflectivity of the filter, and for providing low reflection and high transmission for visible light. Each of these near-infrared-reflection-boosting groups including a high refractive index layer (40 and 42) and at least one low refractive index layer (46 and 48). The high index layer has an optical thickness of about one-quarter wavelength at a near-infrared wavelength, and the low refractive index layer has a refractive index of less than one-quarter wavelength at the near-infrared wavelength.
-
Citations
16 Claims
-
1. An optical interference filter for a substrate, comprising:
-
ten layers, said layers designated the first through the tenth in consecutive numerical order beginning with the layer furthest from the substrate; said first layer of a material having a low refractive index and having an optical thickness of about one-eighth wavelength at a first wavelength in the near-infrared spectral region; said second and tenth layers of a material having a high refractive index and having an optical thickness of about one-quarter wavelength at said first wavelength; said third and ninth layers of a material having a low refractive index and having an optical thickness between one-quarter and one eighth wavelength at said first wavelength; said fourth and eighth layers of a material having a high refractive index and having an optical thickness of less than one-quarter wavelength at a second wavelength in the visible spectrum; said fifth and seventh layers being metal layers and having a thickness between about 12.5 and 30.0 nanometers; said sixth layer of a material having a high refractive index and having an optical thickness less than one-half wavelength at said second wavelength; said first wavelength being between about 800 and 1250 nanometers and said second wavelength being between about 480 and 560 nanometers; and said high refractive index being between about 1.65 and 2.65 at a wavelength of about 520 nm and said low refractive index being between about 1.35 and 1.65 at a wavelength of about 520 nm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. An optical interference filter for a substrate, comprising:
-
twelve layers, said layers designated the first through the twelfth in consecutive numerical order beginning with the layer furthest from the substrate; said first layer of a material having a low refractive index and having an optical thickness of about one-eighth wavelength at a first wavelength in the near-infrared spectral region; said second and twelfth layers of a material having a high refractive index and having an optical thickness of about one-quarter wavelength at said first wavelength; said third and eleventh layers of a material having a low refractive index and having an optical thickness between one-quarter and one-eighth wavelength at said first wavelength; said fourth and tenth layers of a material having a high refractive index and having an optical thickness of less than one-quarter wavelength at a second wavelength in the visible spectrum; said fifth, seventh and ninth layers being metal layers and having a thickness between about 12.5 and 30.0 nanometers; said sixth and eighth layers of a material having a high refractive index and having an optical thickness less than one-half wavelength at said second wavelength; said first wavelength being between about 800 and 1250 nanometers and said second wavelength being between about 480 and 560 nanometers; and said high refractive index being between about 1.65 and 2.65 at a wavelength of about 520 nm and said low refractive index being between about 1.35 and 1.65 at a wavelength of about 520 nm. - View Dependent Claims (13, 14, 15, 16)
-
Specification