Optical system having a diffractive optical element, and optical apparatus
First Claim
1. An optical system, comprising:
- a diffractive optical element having a diffraction grating provided, on a lens surface having curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis, wherein a sign of the curvature of the lens surface having said diffraction grating provided thereon is the same as a sign of a focal length, in a design wavelength, of a system composed of, in said optical system, a surface disposed nearest to a front side to a surface disposed immediately before the lens surface having said diffraction grating thereon, and is different from a sign of a distance from the optical axis to a position where a center ray of an off-axial light flux enters the lens surface having said diffraction grating provided thereon, wherein the following condition is satisfied;
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Abstract
An optical system includes a diffractive optical element having a diffraction grating provided, on a lens surface having a curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis. The sign of the curvature of the lens surface having the diffraction grating provided thereon is the same as the sign of a focal length, at a design wavelength, of a system composed of, in the optical system, a surface disposed nearest to an object side to a surface disposed immediately before the lens surface having the diffraction grating provided thereon, and is different from the sign of the distance from the optical axis to a position where the center ray of an off-axial light flux enters the lens surface having the diffraction grating provided thereon. Further, the apex of an imaginary cone formed by extending a non-effective surface of the diffraction grating is located adjacent to the center of curvature of the lens surface having the diffraction grating provided thereon.
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Citations
16 Claims
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1. An optical system, comprising:
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a diffractive optical element having a diffraction grating provided, on a lens surface having curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis, wherein a sign of the curvature of the lens surface having said diffraction grating provided thereon is the same as a sign of a focal length, in a design wavelength, of a system composed of, in said optical system, a surface disposed nearest to a front side to a surface disposed immediately before the lens surface having said diffraction grating thereon, and is different from a sign of a distance from the optical axis to a position where a center ray of an off-axial light flux enters the lens surface having said diffraction grating provided thereon, wherein the following condition is satisfied;
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An optical apparatus comprising:
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an optical system comprising a diffractive optical element having a diffraction grating provided, on a lens surface having curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis, wherein a sign of the curvature of the lens surface having said diffraction grating provided thereon is the same as a sign of a focal length, in a design wavelength, of a system composed of, in said optical system, a surface disposed nearest to a front side to a surface disposed immediately before the lens surface having said diffraction grating thereon, and is different from a sign of a distance from the optical axis to a position where a center ray of an off-axial light flux enters the lens surface having said diffraction grating provided thereon, wherein the following condition is satisfied;
- View Dependent Claims (10)
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11. An optical system, comprising:
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a diffractive optical element having a diffraction grating provided, on a lens surface having curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis, wherein a sign of the curvature of the lens surface having said diffraction grating provided thereon is the same as a sign of a focal length, in a design wavelength, of a system composed of, in said optical system, a surface disposed nearest to a front side to a surface disposed immediately before the lens surface having said diffraction grating thereon, and is different from a sign of a distance from the optical axis to a position where a center ray of an off-axial light flux enters the lens surface having said diffraction grating provided thereon, wherein an apex of an imaginary cone formed by extending a non-effective surface of said diffraction grating is located adjacent to the center of curvature of the lens surface having said diffraction grating provided thereon, wherein said diffraction grating is a laminated diffraction grating, and wherein said laminated diffraction grating is an adjacently-laminated diffraction grating in which two diffraction gratings are disposed adjacent to each other across an air layer. - View Dependent Claims (12, 13, 14, 15)
an optical system according to claim 11.
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14. An optical apparatus according to claim 13, wherein said optical apparatus is selected from the group of optical apparatuses consisting of an image pickup apparatus, a film camera, a video camera, a digital camera, an observation apparatus, a telescope, a binocular, a projection exposure apparatus, and a stepper for manufacturing a semiconductor device.
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15. An optical apparatus according to claim 14, wherein said adjacently-laminated diffraction grating is provided between two adjacent lens surfaces having substantially the same curvature, and is composed of three layers, including, in order from the front side, a first layer, a second layer and a third layer, said second layer being the air layer.
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16. An optical system, comprising:
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a diffractive optical element having a diffraction grating provided, on a lens surface having curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis, wherein a sign of the curvature of the lens surface having said diffraction grating provided thereon is the same as a sign of a focal length, in a design wavelength, of a system composed of, in said optical system, a surface disposed nearest to a front side to a surface disposed immediately before the lens surface having said diffraction grating thereon, and is different from a sign of a distance from the optical axis to a position where a center ray of an off-axial light flux enters the lens surface having said diffraction grating provided thereon, wherein the following condition is satisfied;
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Specification