Four-layer antireflection coating for deposition in in-like DC sputtering apparatus
First Claim
1. A coating on a substrate for reduction of reflection at a given wavelength, comprising:
- four layers designated the first, second, third, and fourth in consecutive numerical order beginning with the layer farthest from the substrate;
said first layer having a refractive index less than the refractive index of the substrate and an optical thickness of about one-quarter of said wavelength;
said second layer having a refractive index greater than 2.2 and having an optical thickness of about one-half of said wavelength;
said third layer having a refractive index less than said second layer;
said fourth layer having a refractive index greater than the refractive index of said third layer but less than about 2.0; and
said third and fourth layers having a combined optical thickness less than about one quarter of said wavelength.
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Abstract
An antireflection coating for a substrate including four layers and having optimized photopic reflectance and optimized for deposition by sputtering. The first layer (the layer farthest from the substrate) has a refractive index less than the refractive index of the substrate and a thickness of about one-quarter wavelength. The second layer (the layer adjacent the first layer) has an refractive index greater than about 2.2 and a thickness of about a half wavelength. The third layer has refractive index less than that of the second layer. The fourth layer (the layer adjacent the substrate) has a refractive index less than about 2.0 and greater than that of the third layer. The combined thickness of the third and fourth layers is less than about a quarter wavelength. The first and third layers may include silicon dioxide. The second layer may include titanium dioxide or niobium oxide. The fourth layer may include indium oxide, tin oxide, indium tin oxide, or zinc oxide.
64 Citations
9 Claims
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1. A coating on a substrate for reduction of reflection at a given wavelength, comprising:
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four layers designated the first, second, third, and fourth in consecutive numerical order beginning with the layer farthest from the substrate; said first layer having a refractive index less than the refractive index of the substrate and an optical thickness of about one-quarter of said wavelength; said second layer having a refractive index greater than 2.2 and having an optical thickness of about one-half of said wavelength; said third layer having a refractive index less than said second layer; said fourth layer having a refractive index greater than the refractive index of said third layer but less than about 2.0; and said third and fourth layers having a combined optical thickness less than about one quarter of said wavelength. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A coating on a substrate for reduction of reflection at a given wavelength, comprising:
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four layers designated the first, second, third, and fourth in consecutive numerical order beginning with the layer farthest from the substrate; said first layer having a refractive index less than the refractive index of the substrate and an optical thickness of about one-quarter of said wavelength; said second layer including niobium oxide and having a refractive index greater than 2.2 and having an optical thickness of about one-half of said wavelength; said third layer having a refractive index less than said second layer; said fourth layer having a refractive index greater than the refractive index of said third layer but less than 2.0; and said third and fourth layers having a combined optical thickness less than about one quarter of said wavelength.
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Specification
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- Resources
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Current AssigneeTru Vue Inc. (Apogee Enterprises Incorporated)
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Original AssigneeViratec Thin Films, Inc. (Apogee Enterprises Incorporated)
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InventorsDickey, Eric R., Bjornard, Erik J., Steffenhagen, Debra M.
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Primary Examiner(s)NOT, DEFINED
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Application NumberUS08/165,438Time in Patent Office641 DaysField of Search359/580, 359/582, 359/586, 359/588US Class Current359/580CPC Class CodesC03C 17/3417 all coatings being oxide co...G02B 1/116 including electrically cond...
