Optical scanner using plane linear diffraction gratings on a rotating spinner
First Claim
1. An optical scanning system including a spinner having formed thereon at least one plane linear diffraction grating having a constant grating period d,a reconstruction light source of wavelength λ
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r which provides a beam of light directed at an angle of incidence θ
i to illuminate said grating,means for rotating said spinner so that said grating rotates through a rotation angle θ
R and diffracts a portion of the incident light at a diffraction angle θ
dsaid incidence angle θ
i having a value of between 0° and
89.445°
said diffraction angle θ
d, having a value between 38.17° and
90°
, the ratio of the wavelength λ
r to the spacing d having a value of between 1 and 1.618.
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Accused Products
Abstract
An optical scanning system including a spinner containing at least one plane linear diffraction grating. As the spinner is rotated, a plane reconstruction wave of wavelength λr is directed onto the grating creating a diffracted wavefront which can be focused onto an image plane. The grating is constructed so that the ratio of the reconstruction wavelength λr to the grating period d is a value lying between the range of 1 and 1.618. The angles of incidence and diffraction of the reconstruction wavefront in a preferred embodiment, approximate 45°.
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Citations
17 Claims
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1. An optical scanning system including a spinner having formed thereon at least one plane linear diffraction grating having a constant grating period d,
a reconstruction light source of wavelength λ -
r which provides a beam of light directed at an angle of incidence θ
i to illuminate said grating,means for rotating said spinner so that said grating rotates through a rotation angle θ
R and diffracts a portion of the incident light at a diffraction angle θ
dsaid incidence angle θ
i having a value of between 0° and
89.445°
said diffraction angle θ
d, having a value between 38.17° and
90°
, the ratio of the wavelength λ
r to the spacing d having a value of between 1 and 1.618. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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r which provides a beam of light directed at an angle of incidence θ
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12. A method of constructing an optical scanning system comprising the steps of:
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providing a spinner member having disposed thereon a photosensitive medium; splitting a plane object beam of coherent radiation having a wavelength λ
f into a first object beam and a second reference beam, both beams lying in the plane formed by the spinner normal and the spinner diameter;directing said first beam to impinge on said medium at an angle φ
o with respect to spinner normal;directing said second beam to impinge on said medium at an angle φ
r with respect to normal and in the same plane as said first beam, intersecting the first beam at said medium to form an interference fringe pattern constituting a plane linear diffraction grating having a constant grating period d,directing a third reconstruction beam of radiation to impinge onto said grating at an angle of incidence θ
i said angle lying between 0° and
89.445°
, the wavelength λ
r of said reconstruction beam having a value between 1 and 1.618 times the value of grating period d;providing means for rotating said spinner so that said grating rotates through a rotation angle θ
R and diffracts a portion of the incident light at a diffraction angle θ
d lying between 38.17° and
90°
. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification