Optical element, imaging optical system, and optical apparatus
AssigneeCanon Kabushiki Kaisha
InventorKazue Uchida
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Abstract
An optical element for an imaging optical system includes a substrate including a curved surface, and a multilayer film formed on the curved surface. The multilayer film includes a plurality of first films made of a first material and a plurality of second films made of a second material, each of the plurality of first films and each of the plurality of second films are alternately laminated. A predetermined inequality is satisfied.
Claims15
An optical element for an imaging optical system, the optical element comprising a substrate including a curved surface, and a multilayer film formed on the curved surface,
- wherein the multilayer film includes a plurality of first films made of a first material and a plurality of second films made of a second material, each of the plurality of first films and each of the plurality of second films are alternately laminated, and
- wherein the following inequalities are satisfied:
- φ
- ≥
- 20
-
- °
- 0.75
- ≤
- D
- Q
- /
- D
- C
- ≤
- 0.95
- 1.4
- ≤
- n
- L
- (
- 587.56
- )
- ≤
- 1.6
- 1.9
- ≤
- n
- H
- (
- 587.56
- )
- ≤
- 2.5
- n
- H
- (
- 587.56
- )
- -
- n
- L
- (
- 587.56
- )
- ≥
- 0.4
- 1
- /
- (
- n
- H
- (
- 420
- )
- -
- n
- H
- (
- 680
- )
- )
- ≥
- 4.5
- where φ is a maximum value of a half open angle in an optically effective area of the curved surface, DC is a total film thickness of the multilayer film at a position at which the half open angle is 0°, DQ is a total film thickness of the multilayer film at a position at which the half open angle is φ, nL(λ) is a refractive index of the first material at a wavelength λ [nm], and nH(λ) is a refractive index of the second material at the wavelength λ [nm].
An imaging optical system comprising an optical element,
- wherein the optical element includes a substrate including a curved surface, and a multilayer film formed on the curved surface,
- wherein the multilayer film includes a plurality of first films made of a first material and a plurality of second films made of a second material, each of the plurality of first films and each of the plurality of second films are alternately laminated, and
- wherein the following inequalities are satisfied:
- φ
- ≥
- 20
-
- °
- 0.75
- ≤
- D
- Q
- /
- D
- C
- ≤
- 0.95
- 1.4
- ≤
- n
- L
- (
- 587.56
- )
- ≤
- 1.6
- 1.9
- ≤
- n
- H
- (
- 587.56
- )
- ≤
- 2.4
- n
- H
- (
- 587.56
- )
- -
- n
- L
- (
- 587.56
- )
- ≥
- 0.4
- 1
- /
- (
- n
- H
- (
- 420
- )
- -
- n
- H
- (
- 680
- )
- )
- ≥
- 4.5
- where φ is a maximum value of a half open angle in an optically effective area of the curved surface, DC is a total film thickness of the multilayer film at a position at which the half open angle is 0°, DQ is a total film thickness of the multilayer film at a position at which the half open angle is φ, nL(λ) is a refractive index of the first material at a wavelength λ [nm], and nH(λ) is a refractive index of the second material at the wavelength λ [nm].
An optical apparatus comprising an imaging optical system,
- wherein the imaging optical system includes an optical element,
- wherein the optical element includes a substrate including a curved surface, and a multilayer film formed on the curved surface,
- wherein the multilayer film includes a plurality of first films made of a first material and a plurality of second films made of a second material, each of the plurality of first films and each of the plurality of second films are alternately laminated, and
- wherein the following inequalities are satisfied:
- φ
- ≥
- 20
-
- °
- 0.75
- ≤
- D
- Q
- /
- D
- C
- ≤
- 0.95
- 1.4
- ≤
- n
- L
- (
- 587.56
- )
- ≤
- 1.6
- 1.9
- ≤
- n
- H
- (
- 587.56
- )
- ≤
- 2.4
- n
- H
- (
- 587.56
- )
- -
- n
- L
- (
- 587.56
- )
- ≥
- 0.4
- 1
- /
- (
- n
- H
- (
- 420
- )
- -
- n
- H
- (
- 680
- )
- )
- ≥
- 4.5
- where φ is a maximum value of a half open angle in an optically effective area of the curved surface, DC is a total film thickness of the multilayer film at a position at which the half open angle is 0°, DQ is a total film thickness of the multilayer film at a position at which the half open angle is φ, nL(λ) is a refractive index of the first material at a wavelength λ [nm], and nH(λ) is a refractive index of the second material at the wavelength λ [nm].
Dependencies are inferred from the claim text.