DC reactively sputtered antireflection coatings

• US 5,105,310 A
• Filed: 10/11/1990
• Issued: 04/14/1992
• Est. Priority Date: 10/11/1990
• Status: Expired due to Term

• Current Assignee: Tru Vue Inc. (Apogee Enterprises Incorporated)
• Original Assignee: Viratec Thin Films, Inc. (Apogee Enterprises Incorporated)
• Inventors: Dickey, Eric R.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): RYAN, JAY
• Application Number:
  US07/595,552
• Time in Patent Office: 551 Days
• Field of Search: 359/580, 359/581, 359/586, 359/589
• US Class Current: 359/586
• CPC Class Codes: C03C 17/3411 with at least two coatings of inorganic materials C03C17/36, C03C17/42 take precedence
• CPC Class Codes: G02B 1/115 Multilayers
• CPC Class Codes: G02B 1/116 including electrically conducting layers

Abstract

A multilayer antireflection coating designed for deposition in in-line coating machines by DC reactive sputtering. About half of the total thickness of the coating may be formed from zinc oxide which has a high sputtering rate.

Claims

1. An antireflection coating for a substrate, comprising:

five adjoining layers, said layers designated the first, second, third, fourth, and fifth in consecutive numerical order beginning with the layer farthest from said substrate;

said first layer having a refractive index less than the refractive index of said substrate and an optical thickness of about 0.25λ

_O ;

said second layer having a refractive index greater than about 2.20 and an optical thickness less than about 0.25λ

_O ;

said third layer having a refractive index less than said second layer and an optical thickness between about 0.25λ

_O and 0.5λ

_O ;

said fourth layer having a refractive index less than that of said third layer and an optical thickness less than about 0.25λ

_O ;

said fifth layer having a refractive index greater than the refractive index of said substrate and said fourth layer, and an optical thickness less than about 0.25λ

_O ; and

λ

_O being between about 480 nm and 560 nm.

2. The coating of claim 1 wherein said third layer includes in contact with said second layer, a first sub-layer having a refractive index less than that of said second layer, and in contact with said first sub-layer and said fourth layer, a second sub-layer having a refractive index less than that of said first sub-layer and greater than that of said fourth layer.

3. The coating of claim 1 wherein said third layer includes in contact with said second layer, a first sub-layer having a refractive index less than that of said second layer and greater than of said fourth layer, and in contact with said first sub-layer and said fourth layer, a second sub-layer having a refractive index greater than of said first sub-layer and less than of said second layer.

4. The coating of claim 1 wherein said third layer includes at least two sub-layers each having a refractive index less than that of said second layer and greater than that of said fourth layer.

5. The coating of claim 1 wherein at least one layer includes at least two sub-layers.

6. An antireflection coating for a substrate, comprising:

six adjoining layers, said layers being designated the first, second, third, fourth, fifth, and sixth in consecutive numerical order beginning with the layer farthest from said substrate;

said first layer having a refractive index less than that of said substrate and an optical thickness of about 0.25λ

_O, said second layer having a refractive index greater than about 2.2;

said third layer having a refractive index less than that of said second layer;

said fourth layer;

having a refractive index less than the refractive index of said third layer, said fifth layer having a refractive index less than that of said fourth layer and having an optical thickness less than about 0.25λ

_O, said sixth layer having a refractive index greater than that of said substrate and greater than that of said fifth layer and an optical thickness less than about 0.25λ

_O ;

said second, third, and fourth layers having a combined optical thickness of about 0.5λ

_O, and λ

_O being between about 480 and 560 nm.

7. An antireflection coating for a substrate, comprising:

six adjoining layers, said layers being designated the first, second, third, fourth, fifth and sixth in consecutive numerical order beginning with the layer farthest from said substrate;

said first layer having a refractive index less than that of said substrate and an optical thickness of about 0.25λ

_O, said second layer having a refractive index greater than about 2.2;

said third layer having a refractive index less than that of said second layer, said fourth layer having a refractive index greater than that of said third layer and less than that of said second layer, said fifth layer having a refractive index less than that of said fourth layer and an optical thickness less than about 0.25λ

_O ;

said sixth layer having a refractive index greater than that of said substrate and said fifth layer and an optical thickness less than about 0.25λ

_O ;

said second, third, and fourth layers having a combined optical thickness of about 0.5λ

_O, and λ

_O being between about 480 nm and 560 nm.

8. An antireflection coating for a substrate, comprising:

four adjoining layers, said layers being designated the first, second, third, and fourth in consecutive numerical order beginning with the layer farthest from said substrate;

said first layer having a refractive index less than that of said substrate and an optical thickness of about 0.25λ

_O ;

said fourth layer having a refractive index greater than that of said substrate and an optical thickness less than about 0.25_O ;

said third layer having an optical thickness of about 0.25λ

_O and a refractive index less than that of said fourth layer;

said second layer having a thickness of about 0.5λ

_O and including at least two adjacent sub-layers, the sub-layer in contact with said first layer having a refractive index greater than about 2.2 and all other sub-layers having a refractive index less than about 2.2 but greater than the refractive index of said third layer, and λ

_O being between about 480 nm and 560 nm.

9. An antireflection coating for a substrate, comprising:

five adjoining layers, said layers being designated the first, second, third, fourth, and fifth in consecutive numerical order beginning with the layer farthest from said substrate;

said first layer having a refractive index of about 1.46 at a wavelength λ

_O and an optical thickness of about 0.266λ

_O ;

said second layer having a refractive index of about 2.35 at a wavelength λ

_O and an optical thickness of about 0.110λ

_O ;

said third layer having a refractive index of about 2.01 at a wavelength λ

_O and an optical thickness of about 0.368λ

_O ;

said fourth layer a refractive index of about 1.46 at a wavelength λ

_O and an optical thickness of about 0.117λ

_O ;

said fifth layer having a refractive index of about 2.35 at a wavelength λ

_O and an optical thickness of about 0.028λ

_O, and λ

_O being about 510 nm.

10. An antireflection coating for a substrate, comprising:

six adjoining layers, said layers being designated the first, second, third, fourth, fifth, and sixth in consecutive numerical order beginning with the layer farthest from said substrate;

said first layer having a refractive index of about 1.46 and an optical thickness of about 0.268λ

_O ;

said second layer having a refractive index of about 2.35 and an optical thickness of about 0.072λ

_O ;

said third layer having a refractive index of about 2.14 and an optical thickness of about 0.170λ

_O ;

said fourth layer having a refractive index of about 2.01 and an optical thickness of about 0.270λ

_O ;

said fifth layer having a refractive index of about 1.46 and having an optical thickness of about 0.120λ

_O ;

said sixth layer having a refractive index of about 2.35 and an optical thickness of about 0.030λ

_O ; and

λ

_O being about 510 nm.