Optical system which utilizes polarized light
First Claim
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1. An optical system comprising a source of unpolarized light having a wavelength λ
- and a polarizing element in the form of a layer comprising an isotropic material having a refractive index ni and an anisotropic material which separates said unpolarized light into an ordinary polarization component and an extraordinary polarization component, said anisotropic material having refractive indices na,e and na,o, in which ni is substantially equal to na,e or na,o, whereby one of said polarization components is diffused in the polarizing element to form a diffused polarization component, the optical system further comprising means for retroreflecting at least a part of the diffused polarization component toward the source of unpolarized light.
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Abstract
An optical system includes comprising a polarizing element in the form of a layer which comprises an isotropic material having a refractive index ni and an anisotropic material having refractive indices na,e and na,o. The refractive index ni is substantially equal to na,e or na,o. The optical system includes a retroflector for back-reflecting the polarization component diffused in the polarizing element.
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Citations
14 Claims
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1. An optical system comprising a source of unpolarized light having a wavelength λ
- and a polarizing element in the form of a layer comprising an isotropic material having a refractive index ni and an anisotropic material which separates said unpolarized light into an ordinary polarization component and an extraordinary polarization component, said anisotropic material having refractive indices na,e and na,o, in which ni is substantially equal to na,e or na,o, whereby one of said polarization components is diffused in the polarizing element to form a diffused polarization component, the optical system further comprising means for retroreflecting at least a part of the diffused polarization component toward the source of unpolarized light.
- View Dependent Claims (2, 3, 4, 5, 6)
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7. An optical system comprising a source of unpolarized light having a wavelength λ
- and a polarizing element in the form of a layer comprising an isotropic material having a refractive index ni and an anisotropic material which separates said unpolarized light into an ordinary polarization component and an extraordinary polarization component, said anisotropic material having refractive indices na,e and na,o, in which ni is substantially equal to na,e or na,o, whereby one of said polarization components is diffused in the polarizing element to form a diffused polarization component, and wherein the anisotropic material is formed by particles separated by a distance d for which it holds that;
space="preserve" listing-type="equation">0.5λ
<
φ
<
10λin which φ
is the maximum dimension of the particles, and it holds for the distance d between the particles that;
space="preserve" listing-type="equation">10λ
>
d>
0.5λand it further holds that;
space="preserve" listing-type="equation">0.3>
|n.sub.i -n.sub.a,e |>
0.01.whereby at least part of the diff-used polarization component is retroreflected toward the source of unpolarized light. - View Dependent Claims (8, 9, 10)
- and a polarizing element in the form of a layer comprising an isotropic material having a refractive index ni and an anisotropic material which separates said unpolarized light into an ordinary polarization component and an extraordinary polarization component, said anisotropic material having refractive indices na,e and na,o, in which ni is substantially equal to na,e or na,o, whereby one of said polarization components is diffused in the polarizing element to form a diffused polarization component, and wherein the anisotropic material is formed by particles separated by a distance d for which it holds that;
- 11. An optical system comprising a source of unpolarized light, a polarizing element in the form of a layer comprising an isotropic material having a refractive index ni and an anisotropic material which separates said unpolarized light into an ordinary polarization component and an extraordinary polarization component, said anisotropic material having refractive indices na,e and na,o, in which ni is substantially equal to na,e or na,o, whereby one of said polarization components is diffused in the polarizing element to form a diffused polarization component, and means for retroreflecting at least part of the diffused polarization component toward said source of unpolarized light, said means comprising a flat element with a relief structure facing said polarizing element oppositely from said light source, said relief structure reflecting light having an angle of incidence which is larger than a critical angle Θ
Specification