Imaging optical system
First Claim
Patent Images
1. An imaging optical system comprising:
- at least one diffractive optical element having a positive refractive power, said at least one diffractive optical element condensing a first order diffracted light;
at least one first refractive optical element having a positive refractive power; and
at least one second refractive optical element having a negative refractive power;
wherein said imaging optical system satisfies the following condition (1) regardless of a focal length of said imaging optical system as a whole;
space="preserve" listing-type="equation">0.005<
f/f.sub.DOE <
0.05 (1)wherein the reference symbol f represents a focal length of said imaging optical system as a whole and the reference symbol fDOE designates a focal length of said at least one diffractive optical element.
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Abstract
An imaging optical system comprising at least one diffractive optical element having a positive refractive power, at least one refractive optical element having a positive refractive power and at least one refractive optical element having a negative refractive power; and characterized in that it favorably corrects aberrations, in particular, chromatic aberration.
92 Citations
14 Claims
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1. An imaging optical system comprising:
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at least one diffractive optical element having a positive refractive power, said at least one diffractive optical element condensing a first order diffracted light; at least one first refractive optical element having a positive refractive power; and at least one second refractive optical element having a negative refractive power; wherein said imaging optical system satisfies the following condition (1) regardless of a focal length of said imaging optical system as a whole;
space="preserve" listing-type="equation">0.005<
f/f.sub.DOE <
0.05 (1)wherein the reference symbol f represents a focal length of said imaging optical system as a whole and the reference symbol fDOE designates a focal length of said at least one diffractive optical element. - View Dependent Claims (2, 3, 4, 5)
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6. An imaging apparatus comprising:
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an imaging optical system including at least one diffractive optical element having a positive refractive power, said at least one diffractive optical element condensing a first order diffracted light; at least one first refractive optical element having a positive refractive power; at least one second refractive optical element having a negative refractive power; and an image pickup device for receiving an image formed by said at least one diffractive optical element, said at least one first refractive optical element, and said at least one second refractive optical element; wherein said imaging apparatus satisfies the following condition (2);
##EQU1## wherein the reference symbol E(λ
) represents a diffraction efficiency of said at least one diffractive optical element at a wavelength λ
, the reference symbol T(λ
) designates transmittance of said at least one diffractive optical element, said at least one first refractive optical element, and said at least one second refractive optical element as a whole at the wavelength λ
, and the reference symbol B(λ
) denotes a spectral sensitivity characteristic of said image pickup device. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. An imaging optical system comprising:
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at least one diffractive optical element having a positive refractive power, said at least one diffractive optical element condensing a first order diffracted light; at least one first refractive optical element having a positive refractive power; and at least one second refractive optical element having a negative refractive power; wherein said at least one diffractive optical element satisfies the following condition; 450 nm<
λ
MAX <
600 nmwherein the reference symbol λ
MAX represents a wavelength at which said at least one diffractive optical element has a maximum diffractive efficiency. - View Dependent Claims (14)
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Specification