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US 2025/0355244 A1Published application
Zoom lens and image pickup apparatus
AssigneeCanon Kabushiki Kaisha
InventorTakashi OKADA
Life of this patent
Estimating the term…
Abstract
A zoom lens includes a plurality of lens units. Each distance between adjacent lens units changes during zooming. At least one of the plurality of lens units has a diffractive surface with controlled wavelength dispersion. A predetermined inequality is satisfied.
Claims18
A zoom lens comprising:
- a plurality of lens units,
- wherein each distance between adjacent lens units changes during zooming,
- wherein at least one of the plurality of lens units has a diffractive surface with controlled wavelength dispersion, and
- wherein the following inequality is satisfied:
- 0.28
- ≤
- 1
- /
- v
- 0
- ≤
- 0.
- where ν0 is an Abbe number of the diffractive surface and satisfies the following equation, a reference wavelength is d-line, a primary dispersion is F-line and C-line, ψ(λd), ψ(λF) and ψ(λC) are optical path difference functions at wavelengths of the d-line, the F-line and the C-line, respectively, P(λd), P(λF) and P(λC) are optical path difference dispersions of a surface at the wavelengths of the d-line, the F-line, and the C-line, respectively:
- 1
- v
- 0
- ≡
- ψ
-
- (
- λ
- F
- )
- -
- ψ
-
- (
- λ
- C
- )
- ψ
-
- (
- λ
- d
- )
- =
- λ
- F
-
- P
-
- (
- λ
- F
- )
- -
- λ
- C
-
- P
-
- (
- λ
- C
- )
- λ
- d
-
- P
-
- (
- λ
- d
- )
- .
63 more elements
A zoom lens comprising:
- a plurality of lens units,
- wherein each distance between adjacent lens units changes during zooming,
- wherein at least one of the plurality of lens units has a diffractive surface with controlled wavelength dispersion,
- wherein at least one of the plurality of lens units has a refractive surface, and
- wherein the following inequality is satisfied:
- 1
- /
- v
- 0
- ≤
- 0.
- where ν0 is an Abbe number of the diffractive surface and satisfies the following equation, a reference wavelength is d-line, a primary dispersion is F-line and C-line, ψ(λd), ψ(λF) and ψ(λC) are optical path difference functions at wavelengths of the d-line, the F-line and the C-line, respectively, P(λd), P(λF) and P(λC) are optical path difference dispersions of a surface at the wavelengths of the d-line, the F-line, and the C-line, respectively:
- 1
- v
- 0
- ≡
- ψ
-
- (
- λ
- F
- )
- -
- ψ
-
- (
- λ
- C
- )
- ψ
-
- (
- λ
- d
- )
- =
- λ
- F
-
- P
-
- (
- λ
- F
- )
- -
- λ
- C
-
- P
-
- (
- λ
- C
- )
- λ
- d
-
- P
-
- (
- λ
- d
- )
- .
62 more elements
An image pickup apparatus comprising:
- a zoom lens;
- and
- an image sensor configured to capture an object image through the zoom lens,
- wherein the zoom lens includes:
- a plurality of lens units,
- wherein each distance between adjacent lens units changes during zooming,
- wherein at least one of the plurality of lens units has a diffractive surface with controlled wavelength dispersion, and
- wherein the following inequality is satisfied:
- -
- 0.28
- ≤
- 1
- /
- v
- 0
- ≤
- 0.
- where ν0 is an Abbe number of the diffractive surface and satisfies the following equation, a reference wavelength is d-line, a primary dispersion is F-line and C-line, ψ(λd), ψ(λF) and ψ(λC) are optical path difference functions at wavelengths of the d-line, the F-line and the C-line, respectively, P(λd), P(λF) and P(λC) are optical path difference dispersions of a surface at the wavelengths of the d-line, the F-line, and the C-line, respectively:
- 1
- v
- 0
- ≡
- ψ
-
- (
- λ
- F
- )
- -
- ψ
-
- (
- λ
- C
- )
- ψ
-
- (
- λ
- d
- )
- =
- λ
- F
-
- P
-
- (
- λ
- F
- )
- -
- λ
- C
-
- P
-
- (
- λ
- C
- )
- λ
- d
-
- P
-
- (
- λ
- d
- )
- .
68 more elements
An image pickup apparatus comprising:
- a zoom lens;
- and
- an image sensor configured to capture an object image through the zoom lens,
- wherein the zoom lens includes:
- a plurality of lens units,
- wherein each distance between adjacent lens units changes during zooming,
- wherein at least one of the plurality of lens units has a diffractive surface with controlled wavelength dispersion,
- wherein at least one of the plurality of lens units has a refractive surface, and
- wherein the following inequality is satisfied:
- 1
- /
- v
- 0
- ≤
- 0.
- .
- where ν0 is an Abbe number of the diffractive surface and satisfies the following equation, a reference wavelength is d-line, a primary dispersion is F-line and C-line, ψ(λd), ψ(λF) and ψ(λC) are optical path difference functions at wavelengths of the d-line, the F-line and the C-line, respectively, P(λd), P(λF) and P(λC) are optical path difference dispersions of a surface at the wavelengths of the d-line, the F-line, and the C-line, respectively:
- 1
- v
- 0
- ≡
- ψ
-
- (
- λ
- F
- )
- -
- ψ
-
- (
- λ
- C
- )
- ψ
-
- (
- λ
- d
- )
- =
- λ
- F
-
- P
-
- (
- λ
- F
- )
- -
- λ
- C
-
- P
-
- (
- λ
- C
- )
- λ
- d
-
- P
-
- (
- λ
- d
- )
- .
67 more elements
Dependencies are inferred from the claim text.