Anti-reflection film and optical system using the same

• US 5,885,712 A
• Filed: 03/21/1997
• Issued: 03/23/1999
• Est. Priority Date: 03/22/1996
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Suzuki, Yasuyuki, Otani, Minoru, Ando, Kenji, Kanazawa, Hidehiro, Biro, Ryuji
• Primary Examiner(s): Evans, Elizabeth
• Application Number:
  US08/822,469
• Time in Patent Office: 732 Days
• Field of Search: 428/426, 428/428, 428/433, 428/688, 428/689, 428/702, 423/592, 423/600, 423/624, 423/625
• US Class Current: 428/426
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3452 comprising a fluoride

Abstract

An anti-reflection film is arranged by alternately stacking a plurality of high-refractive index layers containing Al₂ O₃ and a plurality of low-refractive index layers containing SiO₂ on a transparent substrate in turn from the substrate side to the air side, and satisfies:

1.45≦ns≦1.65

1.60≦na≦1.85

0.31λ0≦d1≦0.42λ0

0.38λ0≦d2≦0.45λ0

0.20λ0≦d3≦0.31λ0

0.18λ0≦d4≦0.28λ0

0.20λ0≦d5≦0.30λ0

0.20λ0≦d6≦0.30λ0

where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with the wavelength range from 190 nm to 250 nm, di (unit: nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and λ0 (nm) is the reference wavelength within the wavelength range from 190 nm to 250 nm.

Claims

1. An anti-reflection film arranged by alternately stacking a plurality of high-refractive index layers containing Al₂ O₃ and a plurality of low-refractive index layers containing SiO₂ on a transparent substrate in turn from the substrate side to an air side, and satisfying:

1.45≦

ns≦

1.65

1.60≦

na≦

1.85

0.31λ

0≦

d1≦

0.42λ

0

0.38λ

0≦

d2≦

0.45λ

0

0.20λ

0≦

d3≦

0.31λ

0

0.18λ

0≦

d4≦

0.28λ

0

0.20λ

0≦

d5≦

0.30λ

0

0.20λ

0≦

d6≦

0.30λ

0

where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with a wavelength range from 190 nm to 250 nm, di (unit;

nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and λ

0 (nm) is the reference wavelength within the wavelength range from 190 nm to 250 nm.

2. An anti-reflection film according to claim 1, wherein said substrate comprises fluorite.

3. An anti-reflection film according to claim 1, wherein said anti-reflection film is formed by sputtering.

4. An anti-reflection film according to claim 1, wherein said anti-reflection film is formed by vacuum deposition.

5. An optical system comprising:

a lens, which is coated with an anti-reflection film arranged by alternately stacking a plurality of high-refractive index layers containing Al₂ O₃ and a plurality of low-refractive index layers containing SiO₂ on a transparent substrate in turn from the substrate side to an air side, and satisfying;

1.45≦

ns≦

1.65

1.60≦

na≦

1.85

0.31λ

0≦

d1≦

0.42λ

0

0.38λ

0≦

d2≦

0.45λ

0

0.20λ

0≦

d3≦

0.31λ

0

0.18λ

0≦

d4≦

0.28λ

0

0.20λ

0≦

d5≦

0.30λ

0

0.20λ

0≦

d6≦

0.30λ

0

where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with a wavelength range from 190 nm to 250 nm, di (unit;

nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and λ

0 (nm) is the reference wavelength within the wavelength range from 190 nm to 250 nm.

6. An anti-reflection film arranged by alternately stacking a plurality of high-refractive index layers containing Al₂ O₃ and a plurality of low-refractive index layers containing SiO₂ on a transparent substrate in turn from the substrate side to an air side, and satisfying:

1.45≦

ns≦

1.65

1.60≦

na≦

1.85

0.06λ

0≦

d1≦

0.17λ

0

0.48λ

0≦

d2≦

0.59λ

0

0.25λ

0≦

d3≦

0.35λ

0

0.18λ

0≦

d4≦

0.28λ

0

0.20λ

0≦

d5≦

0.30λ

0

0.20λ

0≦

d6≦

0.30λ

0

where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with a wavelength range from 190 nm to 250 nm, di (unit;

nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and λ

0 (nm) is the reference wavelength within the wavelength range from 190 nm to 250 nm.

7. An anti-reflection film according to claim 6, wherein said substrate comprises fluorite.

8. An anti-reflection film according to claim 6, wherein said anti-reflection film is formed by sputtering.

9. An anti-reflection film according to claim 6, wherein said anti-reflection film is formed by vacuum deposition.

10. An optical system comprising:

a lens, which is coated with an anti-reflection film arranged by alternately stacking a plurality of high-refractive index layers containing Al₂ O₃ and a plurality of low-refractive index layers containing SiO₂ on a transparent substrate in turn from the substrate side to an air side, and satisfying;

1.45≦

ns≦

1.65

1.60≦

na≦

1.85

0.06λ

0≦

d1≦

0.17λ

0

0.48λ

0≦

d2≦

0.59λ

0

0.25λ

0≦

d3≦

0.35λ

0

0.18λ

0≦

d4≦

0.28λ

0

11. 20λ

0≦

d5≦

0.30λ

0

0.20λ

0≦

d6≦

0.30λ

0

where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with a wavelength range from 190 nm to 250 nm, di (unit;

nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and λ

0 (nm) is the reference wavelength within the wavelength range from 190 nm to 250 nm.

14. An anti-reflection film according to claim 11, wherein said substrate comprises fluorite.

15. An anti-reflection film according to claim 11, wherein said anti-reflection film is formed by sputtering.

16. An anti-reflection film according to claim 11, wherein said anti-reflection film is formed by vacuum deposition.

12. An anti-reflection film arranged by alternately stacking a plurality of high-refractive index layers containing Al₂ O₃ and a plurality of low-refractive index layers containing SiO₂ on a transparent substrate in turn from the substrate side to an air side, and satisfying:

1.45≦

ns≦

1.65

1.60≦

na≦

1.85

0.01λ

0≦

d1≦

0.11λ

0

0.57λ

0≦

d2≦

0.67λ

0

0.20λ

0≦

d3≦

0.31λ

0

0.45λ

0≦

d4≦

0.56λ

0

0.15λ

0≦

d5≦

0.26λ

0

0.21λ

0≦

d6≦

0.32λ

0

0.20λ

0≦

d7≦

0.30λ

0

13. 20λ

0≦

d8≦

0.30λ

0

where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with a wavelength range from 190 nm to 250 nm, di (unit;

nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and λ

0 (nm) is the reference wavelength within the wavelength range from 190 nm to 250 nm.

17. An optical system comprising:

a lens, which is coated with an anti-reflection film arranged by alternately stacking a plurality of high-refractive index layers containing Al₂ O₃ and a plurality of low-refractive index layers containing SiO₂ on a transparent substrate in turn from the substrate side to an air side, and satisfying;

1.45≦

ns≦

1.65

1.60≦

na≦

1.85

0.01λ

0≦

d1≦

0.11λ

0

0.57λ

0≦

d2≦

0.67λ

0

0.20λ

0≦

d3≦

0.31λ

0

0.45λ

0≦

d4≦

0.56λ

0

0.15λ

0≦

d5≦

0.26λ

0

0.21λ

0≦

d6≦

0.32λ

0

0.20λ

0≦

d7≦

0.30λ

0

0.20λ

0≦

d8≦

0.30λ

0

where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with a wavelength range from 190 nm to 250 nm, di (unit;

nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and λ

0 (nm) is the reference wavelength within the wavelength range from 190 nm to 250 nm.