DIFFUSER HAVING SHAPE PROFILE FOR REDUCING SPECKLE NOISE AND A LASER PROJECTION SYSTEM EMPLOYING THE SAME
First Claim
1. A diffuser employed in a laser projection system for reducing speckle noise, the diffuser comprising a scattering pattern,wherein the scattering pattern comprises a plurality of scattering ribbons arranged in a direction of a first axis and extending in a direction parallel to a second axis, andeach of the plurality of scattering ribbons comprises a second surface, wherein a height of the second surface with respect to a first surface defined by the first axis and the second axis varies based on a measuring point on the first axis, and the second surface satisfies the Equations
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x h ( x ) = - tan ( β ( x ) )
(x) is an angle between a line tangent to the second surface and the first axis, and α
is a constant.
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Abstract
A diffuser having a shape for reducing speckle noise and a laser projection system including the diffuser are provided. The diffuser is employed by a laser projection system to reduce speckle noise, and includes a scattering pattern. The scattering pattern includes a plurality of scattering ribbons, and a curved surface of each of the plurality of scattering ribbons satisfies equations so that speckle noise is minimized for an aperture size of an optical system.
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Citations
19 Claims
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1. A diffuser employed in a laser projection system for reducing speckle noise, the diffuser comprising a scattering pattern,
wherein the scattering pattern comprises a plurality of scattering ribbons arranged in a direction of a first axis and extending in a direction parallel to a second axis, and each of the plurality of scattering ribbons comprises a second surface, wherein a height of the second surface with respect to a first surface defined by the first axis and the second axis varies based on a measuring point on the first axis, and the second surface satisfies the Equations -
x h ( x ) = - tan ( β ( x ) ) where h(x) is a height of the second surface with respect to the first surface measured from a point x of the first axis if a point on the first surface corresponding to an apex of the second surface is an origin, β
(x) is an angle between a line tangent to the second surface and the first axis, and α
is a constant. - View Dependent Claims (3, 4, 5, 6)
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2. A diffuser employed in a laser projection system for reducing speckle noise, the diffuser comprising a scattering pattern,
wherein the scattering pattern comprises a plurality of scattering ribbons arranged in a direction of a first axis and extending in a direction parallel to a second axis, and each of the plurality of scattering ribbons comprises a second surface, wherein a height of the second surface with respect to a first surface defined by the first axis and the second axis varies based on a measuring point on the first axis, and the second surface satisfies the Equation -
( x ) = h 0 - α x 2 2 , where h(x) is a height of the second surface with respect to the first surface measured from a point x of the first axis if a point on the first surface corresponding to an apex of the second surface is an origin, h0 is a height of an apex of the second surface, and α
is a constant.
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7. A laser projection system comprising:
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a laser light source, an optical modulator which modulates light generated from the light source corresponding to image information, a projection lens unit which projects modulated light on a screen, and a diffuser disposed on an optical path facing the screen, wherein the diffuser oscillates with respect to an optical axis and comprising a scattering pattern, and the scattering pattern has an optimized shape profile to minimize speckle noise with respect to an aperture of the laser projection system. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification