Optical low pass filter utilizing a phase grating
First Claim
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1. An optical low pass filter provided between an image source and an image pickup device including:
- a substrate having a pair of major surfaces,a grating implanted within said substrate and having a surface flush with one of said major surfaces, said grating having a uniform repetitive period and having a refractive index different from that of said substrate, one of said major surfaces receiving image light from said image source and said optical low pass filter deriving image light with a suppressed spatial frequency component higher than a predetermined spatial frequency to be supplied to said image pickup device.
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Abstract
An optical low pass filter including a phase grating, wherein the grating is implanted inwardly from the surface of a substrate, the grating having a uniform repetitive period and having a refractive index different from that of the substrate.
32 Citations
7 Claims
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1. An optical low pass filter provided between an image source and an image pickup device including:
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a substrate having a pair of major surfaces, a grating implanted within said substrate and having a surface flush with one of said major surfaces, said grating having a uniform repetitive period and having a refractive index different from that of said substrate, one of said major surfaces receiving image light from said image source and said optical low pass filter deriving image light with a suppressed spatial frequency component higher than a predetermined spatial frequency to be supplied to said image pickup device. - View Dependent Claims (2, 3, 4, 5)
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6. An optical low pass filter provided between an image source and an image pickup device comprising:
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a substrate composed of glass having a pair of major surfaces thereon, a phase grating formed within said substrate and having a surface flush with one of said major surfaces, said grating having a uniform repetitive period and formed of a glass having a refractive index different from that of said substrate, wherein one of said major surfaces receives image light from said image source and said optical low pass filter derives image light having a supressed spatial frequency component higher than a predetermined spatial frequency to be applied to said image pickup device. - View Dependent Claims (7)
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Specification