Optical element and optical apparatus
AssigneeCanon Kabushiki Kaisha
InventorsDaisuke Sano, Yutaka Yamaguchi
Life of this patent
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Abstract
An optical element including a first layer (011) made of a medium having optical anisotropy, wherein a difference between refractive indexes nh and nl (nh>nl) at a central wavelength λ for first and second polarized lights which enter the optical element and whose polarization directions are different from each other is at least 0.1, and wherein conditions (nt1−nl)·(nl−nt2)≦0 and nt1<nl are satisfied, where nt1 and nt2 denote refractive indexes of a second layer (012) and a third layer (013) optically adjacent to the first layer in both sides of the first layer and made of isotropic media at the central wavelength.
Claims7
An optical element comprising:
- a first layer made of a medium having optical anisotropy,
- wherein a difference between refractive indexes nh and nl (nh>nl) at a central wavelength λ for first and second polarized lights which enter the optical element and whose polarization directions are different from each other is at least 0.1, and
- wherein conditions below are satisfied, where nt1 and nt2 denote refractive indexes of second and third layers optically adjacent to the first layer in both sides of the first layer and made of isotropic media at the central wavelength:
- (nt1−nh)·(nh−nt2)≦0
- nt1>nh
An optical apparatus comprising:
- an optical element,
- wherein the optical element includes a first layer made of a medium having optical anisotropy,
- wherein a difference between refractive indexes nh and nl (nh>nl) at a central wavelength λ for first and second polarized lights which enter the optical element and whose polarization directions are different from each other is at least 0.1, and
- wherein conditions below are satisfied, where nt1 and nt2 denote refractive indexes of second and third layers optically adjacent to the first layer in both sides of the first layer and made of isotropic media at the central wavelength:
- (nt1−nh)·(nh−nt2)≦0
- nt1>nh
Dependencies are inferred from the claim text.