Broad band pass filter including metal layers and dielectric layers of alternating refractive index

Claim 2

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.

Claim 3

The filter of claim 1 wherein said fifth and seventh layers include silver.

Claim 4

The filter of claim 1, wherein said low refractive index material includes a material selected from the group consisting of magnesium fluoride, thorium fluoride, and silicon dioxide, said high refractive index material includes a material selected from the group consisting of zinc sulfide, titanium dioxide, tantalum oxide, niobium oxide, zinc oxide, tin oxide, indium oxide, and indium tin oxide, and said fifth and seventh layers include a metal selected from the group consisting of aluminum, copper, gold, rhodium, and silver.

Claim 5

The filter of claim 1 further including an eleventh layer of a material having said low refractive index and having an optical thickness of about one-eighth wavelength at said first wavelength.

Claim 6

The filter of claim 1 wherein at least one of said first second third fourth sixth, eighth ninth and tenth layers is formed from two or more sub-layers having a different refractive index.

Claim 7

The filter of claim 1, wherein between one of said fifth and seventh layers and a layer adjacent thereto is an auxiliary-layer having a thickness less than about 10 nm, said auxiliary-layer being defined as one or more of the group consisting of adhesion-promoting-layer, glue-layer, barrier-layer, primer-layer, protective-layer, and nucleation-layer.

Claim 8

The filter of claim 1 further including an eleventh layer said eleventh layer including a material selected from the group consisting of titanium nitride, zirconium nitride, hafnium nitride, vanadium nitride, niobium nitride, tantalum nitride, and chromium nitride.

Claim 9

The filter of claim 7 wherein said eleventh layer has a thickness between about 2 and 40 nanometers.

Claim 10

The filter of claim 8 wherein said eleventh layer includes titanium nitride.

Claim 11

The filter of claim 9 wherein said eleventh layer has a thickness between about 2 and 40 nanometers.

Claim 12

The filter of claim 1 further including an eleventh layer, said eleventh layer including a material selected from the group consisting of chromium, cobalt, iron, molybdenum, neodymium, niobium, nickel, palladium, platinum, tantalum, titanium, tungsten, vanadium, and zirconium.

Claim 13

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.

Claim 14

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.

Claim 15

The filter of claim 12 wherein said metal layers are silver layers.

Claim 16

The filter of claim 13, wherein said low refractive index material is thorium fluoride, said high refractive index material is zinc sulphide, and said fifth, seventh, and ninth layers include gold.

Claim 17

The filter of claim 13, wherein said low refractive index material is thorium fluoride, said high refractive index material is zinc sulphide, and said fifth, seventh, and ninth layers include silver.

Claim 18

The filter of claim 12, wherein said low refractive index material includes a material selected from the group consisting of magnesium fluoride, thorium fluoride, and silicon dioxide, said high refractive index material includes a material selected from the group consisting of zinc sulfide, titanium dioxide, tantalum oxide, niobium oxide, zinc oxide, tin oxide, indium oxide, and indium tin oxide, and said fifth, seventh, and ninth layers include a metal selected from the group consisting of aluminum, copper, gold, rhodium, and silver.