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US 12,730,331 B2Granted
Diffractive optical element, optical system, image pickup apparatus, and display apparatus
AssigneeCanon Kabushiki Kaisha
InventorMikio Kobayashi
Life of this patent
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Abstract
A diffractive optical element includes a diffractive area including annular sections concentrically arranged. At least one of the annular sections has a non-circular shape. A predetermined inequality is satisfied.
Claims16
A diffractive optical element comprising:
- a diffractive area including annular sections concentrically arranged,
- wherein at least one of the annular sections has a non-circular shape,
- wherein the annular sections are rotationally symmetric and concentric, and
- wherein the following inequalities are satisfied:
- 6
- <
- P
-
- min
- ×
- Rdc
- /
- Re
- <
- 65
- 0.5
- <
- Rdc
- /
- Re
- <
- 0.95
- 0.7
- <
- Rdc
- /
- RPm
- <
- 1
- .
- 5
-
- 0
- where Rdc (mm) is a shortest one of distances from a center of the annular sections to an outer circumference of the diffractive area, Re (mm) is a radius of one of the annular sections which is farthest from the center, Pmin (μm) is a minimum value of an array pitch of the diffractive optical element, and RPm (mm) is a radius of the annulus having the minimum value Pmin.
31 more elements
Dependencies are inferred from the claim text.