POLARIZER, OPTICAL APPARATUS, LIGHT SOURCE APPARATUS, AND IMAGE PICKUP APPARATUS
First Claim
Patent Images
1. A polarizer comprising:
- a first medium disposed at an emission side;
a second medium disposed at an incident side; and
a plurality of laminated structures provided at a predetermined grating period in a grating period direction, wherein;
the laminated structure includes, in order from the first medium to the second medium, a first dielectric layer, a metallic layer, and a second dielectric layer between the first medium and the second medium,the polarizer is configured to reflect or absorb polarized light oscillating in a direction orthogonal to the grating period direction in a specific wavelength band and to transmit light other than the polarized light, andthe polarizer satisfies;
0.85<
ne*P*cos θ
/λ
<
1.15
and
nH1−
na>
0.5
or
nH2−
nb>
0.5,where λ
represents a wavelength at which a transmittance of the polarized light is minimum, P represents the predetermined grating period, na represents a refractive index of the first medium, and nb represents a refractive index of the second medium, andwhere ne represents an effective refractive index of the first dielectric layer or the second dielectric layer in a direction orthogonal to the grating period direction and parallel to a longitudinal direction of the first dielectric layer or the second dielectric layer, nH1 represents a refractive index of the first dielectric layer, nH2 represents a refractive index of the second dielectric layer, and θ
represents an incident angle of light to the second medium, and ne is given by;
ne=[nH12*W12/P2+nf2*(1−
W1)2/P2]0.5 where W1 represents a grating width of the first dielectric layer, and of represents a refractive index of a medium between each laminated structure, or
ne=[nH22*W22/P2+nf2*(1−
W2)2/P2]0.5 where W2 represents a grating width of the second dielectric layer.
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Abstract
A polarizer includes a first medium disposed at an emission side, a second medium disposed at an incident side, and a plurality of laminated structures provided at a predetermined grating period in a grating period direction, the laminated structure includes, in order from the first medium to the second medium, a first dielectric layer, a metallic layer, and a second dielectric layer between the first medium and the second medium, the polarizer is configured to reflect polarized light oscillating in a direction orthogonal to the grating period direction in a particular wavelength band and to transmit light other than the polarized light, and predetermined expressions are satisfied.
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Citations
17 Claims
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1. A polarizer comprising:
-
a first medium disposed at an emission side; a second medium disposed at an incident side; and a plurality of laminated structures provided at a predetermined grating period in a grating period direction, wherein; the laminated structure includes, in order from the first medium to the second medium, a first dielectric layer, a metallic layer, and a second dielectric layer between the first medium and the second medium, the polarizer is configured to reflect or absorb polarized light oscillating in a direction orthogonal to the grating period direction in a specific wavelength band and to transmit light other than the polarized light, and the polarizer satisfies;
0.85<
ne*P*cos θ
/λ
<
1.15
and
nH1−
na>
0.5
or
nH2−
nb>
0.5,where λ
represents a wavelength at which a transmittance of the polarized light is minimum, P represents the predetermined grating period, na represents a refractive index of the first medium, and nb represents a refractive index of the second medium, andwhere ne represents an effective refractive index of the first dielectric layer or the second dielectric layer in a direction orthogonal to the grating period direction and parallel to a longitudinal direction of the first dielectric layer or the second dielectric layer, nH1 represents a refractive index of the first dielectric layer, nH2 represents a refractive index of the second dielectric layer, and θ
represents an incident angle of light to the second medium, and ne is given by;
ne=[nH12*W12/P2+nf2*(1−
W1)2/P2]0.5where W1 represents a grating width of the first dielectric layer, and of represents a refractive index of a medium between each laminated structure, or
ne=[nH22*W22/P2+nf2*(1−
W2)2/P2]0.5where W2 represents a grating width of the second dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An optical apparatus comprising:
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a light emitting unit; and a polarizer, wherein the polarizer includes; a first medium disposed at an emission side; a second medium disposed at an incident side; and a plurality of laminated structures provided at a predetermined grating period in a grating period direction, wherein; the laminated structure includes, in order from the first medium to the second medium, a first dielectric layer, a metallic layer, and a second dielectric layer between the first medium and the second medium, the polarizer is configured to reflect or absorb polarized light oscillating in a direction orthogonal to the lattice period direction in a specific wavelength band and to transmit light other than the polarized light, and the polarizer satisfies;
0.85<
ne*P*cos θ
/λ
<
1.15
and
nH1−
na>
0.5
or
nH2−
nb>
0.5,where λ
represents a wavelength at which a transmittance of the polarization is minimum, P represents the predetermined grating period, na represents a refractive index of the first medium, and nb represents a refractive index of the second medium, andwhere ne represents an effective refractive index of the first dielectric layer or the second dielectric layer in a direction orthogonal to the grating period direction and parallel to a longitudinal direction of the first dielectric layer or the second dielectric layer, nH1 represents a refractive index of the first dielectric layer, nH2 represents a refractive index of the second dielectric layer, and θ
represents an incident angle of light to the second medium, and ne is given by;
ne=[nH12*W12/P2+nf2*(1−
W1)2/P2]0.5where W1 represents a grating width of the first dielectric layer, and of represents a refractive index of a medium between each laminated structure, or
ne=[nH22*W22/P2+nf2*(1−
W2)2/P2]0.5where W2 represents a grating width of the second dielectric layer, and wherein; a half width of a wavelength band of light of the light emitting unit is not greater than 20 nm, and the polarizer is arranged so as to reflect not less than 50% of the light from the light emitting unit.
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14. A light source apparatus comprising:
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a first light emitting unit configured to emit light having a central wavelength λ
0 and a half width Δ
λ
0;a second light emitting unit configured to emit light having a central wavelength λ
1 and a half width Δ
λ
1; anda polarizer configured to transmit not less than 50% of the light from the first light emitting unit and to reflect not less than 50% of the light from the second light emitting unit into a direction in which the light from the first light emitting unit is transmitted, wherein the polarizer includes; a first medium disposed at an emission side; a second medium disposed at an incident side; and a plurality of laminated structures provided at a predetermined grating period in a grating period direction, wherein; the laminated structure includes, in order from the first medium to the second medium, a first dielectric layer, a metallic layer, and a second dielectric layer between the first medium and the second medium, the polarizer is configured to reflect or absorb polarized light oscillating in a direction orthogonal to the lattice period direction in a specific wavelength band and to transmit light other than the polarized light, and the polarizer satisfies;
0.85<
ne*P*cos θ
/λ
<
1.15
and
nH1−
na>
0.5
or
nH2−
nb>
0.5,where λ
represents a wavelength at which a transmittance of the polarization is minimum, P represents the predetermined grating period, na represents a refractive index of the first medium, and nb represents a refractive index of the second medium, andwhere ne represents an effective refractive index of the first dielectric layer or the second dielectric layer of in a direction orthogonal to the lattice period direction and parallel to a longitudinal direction of the first dielectric layer or the second dielectric layer, nH1 represents a refractive index of the first dielectric layer, nH2 represents a refractive index of the second dielectric layer, and θ
represents an incident angle of light to the second medium, and ne is given by;
ne=[nH12*W12/P2+nf2*(1−
W1)2/P2]0.5where W1 represents a grating width of the first dielectric layer, and of represents a refractive index of a medium between each laminated structure, or
ne=[nH22*W22/P2+nf2*(1−
W2)2/P2]0.5where W2 represents a grating width of the second dielectric layer, and wherein the polarizer satisfies;
Δ
λ
0>
Δ
λ
1
and
λ
min<
λ
1<
λ
maxwhere λ
min represents a minimum value of a wavelength band in which not less than 50% of the light from the second light emitting unit is reflected, and λ
max represents a maximum value of the wavelength band. - View Dependent Claims (15)
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16. An image pickup apparatus comprising:
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an image pickup element; an optical finder configured to optically display an observable object image not through the image pickup element; an electronic viewfinder including a light source and an image display element and configured to display an observable image obtained through the image pickup element; an ocular unit shared by the optical finder and the electronic viewfinder; and an optical path synthesizing unit configured to synthesize light from the optical finder and light from the electronic viewfinder and to emit synthesized light to the ocular unit, wherein the optical path synthesizing unit includes a polarizer arranged so as to transmit the light from the optical finder and to reflect the light from the electronic viewfinder into a direction in which the light from the optical finder is transmitted, and wherein the polarizer includes; a first medium disposed at an emission side; a second medium disposed at an incident side; and a plurality of laminated structures provided at a predetermined grating period in a grating period direction, wherein; the laminated structure includes, in order from the first medium to the second medium, a first dielectric layer, a metallic layer, and a second dielectric layer between the first medium and the second medium, the polarizer is configured to reflect or absorb polarized light oscillating in a direction orthogonal to the grating period direction in a specific wavelength band and to transmit light other than the polarized light, and the polarizer satisfies;
0.85<
ne*P*cos θ
/λ
<
1.15
and
nH1−
na>
0.5
or
nH2−
nb>
0.5,where λ
represents a wavelength in which a transmittance of the polarization is minimum, P represents the predetermined grating period, na represents a refractive index of the first medium, and nb represents refractive index of the second medium, andwhere ne represents an effective refractive index of the first dielectric layer or the second dielectric layer in a direction orthogonal to the grating period direction and parallel to a longitudinal direction of the first dielectric layer or the second dielectric layer, nH1 represents a refractive index of the first dielectric layer, nH2 represents a refractive index of the second dielectric layer, and θ
represents an incident angle of light to the second medium, and ne is given by;
ne=[nH12*W12/P2+nf2*(1−
W1)2/P2]0.5where W1 represents a grating width of the first dielectric layer, and of represents a refractive index of a medium between each laminated structure, or
ne=[nH22*W22/P2+nf2*(1−
W2)2/P2]0.5where W2 represents a grating width of the second dielectric layer. - View Dependent Claims (17)
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Specification