Diffraction device
First Claim
Patent Images
1. A head-up display apparatus, comprising:
- a displaying device for displaying an image; and
an optical system for directing a beam indicative of said image from said displaying device to a viewer, said optical system including;
a beam combiner; and
a relay member for diffracting said beam and making it incident on said beam combiner, at which the beam is rediffracted and directed to the viewer, wherein a half-width of a wavelength spectrum of a diffraction efficiency of said relay member is set to be equal to or greater than 8% of a central wavelength of the wavelength spectrum, andwherein a half-width of a wavelength spectrum of a diffraction efficiency of said beam combiner is smaller than that of said relay member.
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Abstract
The present invention provides a diffraction device having a high diffraction efficiency with respect to a wide-band radiation beam. A diffraction device comprises a substrate and a diffraction grating formed on the substrate, wherein the diffraction grating is formed so that a full-width of wavelength at half maximum of a diffraction efficiency of a beam diffracted by the diffraction grating is not less than about 8% of a value of a center wavelength of the diffracted beam.
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Citations
13 Claims
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1. A head-up display apparatus, comprising:
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a displaying device for displaying an image; and an optical system for directing a beam indicative of said image from said displaying device to a viewer, said optical system including; a beam combiner; and a relay member for diffracting said beam and making it incident on said beam combiner, at which the beam is rediffracted and directed to the viewer, wherein a half-width of a wavelength spectrum of a diffraction efficiency of said relay member is set to be equal to or greater than 8% of a central wavelength of the wavelength spectrum, and wherein a half-width of a wavelength spectrum of a diffraction efficiency of said beam combiner is smaller than that of said relay member. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for transmitting a beam having a plurality of light wavelength components, comprising:
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a first optical fiber for supplying the beam; a second optical fiber for receiving the beam; a first member forming a first diffraction grating for receiving and diffracting the beam from said first optical fiber, wherein a half-width of a wavelength spectrum of a diffraction efficiency of said first diffraction grating is set to be equal to or greater than 8% of a central wavelength of said wavelength spectrum; and a second member forming a second diffraction grating for receiving and diffracting the beam from said first member and directing the beam to said second optical fiber, wherein a half-width of a wavelength spectrum of a diffraction efficiency of said second diffraction grating is smaller than that of said first diffraction grating. - View Dependent Claims (9, 10, 11, 12)
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13. A system for transmitting a beam having a plurality of light wavelength components from a first optical fiber to a second group of optical fibers, said system comprising:
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a first member forming a first diffraction grating for receiving and diffracting the beam from said first optical fiber, wherein a half-width of a wavelength spectrum of a diffraction efficiency of said first diffraction grating is set to be equal to or greater than 8% of a central wavelength of said wavelength spectrum; and a second member forming a second diffraction grating for receiving and diffracting the beam from said first member and directing the beam to said second group of optical fibers, wherein a half-width of a wavelength spectrum of a diffraction efficiency of said second diffraction grating is smaller than that of said first diffraction grating is smaller than that of said first diffraction grating.
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Specification