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US 5,689,521 AGranted
Semiconductor laser light source unit
AssigneeRohm Co., Ltd.
InventorNaotaro Nakata
Life of this patent
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AssigneeRohm Co., Ltd.
InventorNaotaro Nakata
Estimating the term…
A rod lens or a cylindrical lens is disposed in front of a semiconductor laser to increase a divergence angle of a laser beam emitted from the semiconductor laser so as to form a substantially circular far field pattern. In another constitution, there is disposed in front of a semiconductor laser a composite lens having two cylindrical surfaces whose cylindrical axes are perpendicular to each other. The cylindrical surface on the side of the semiconductor laser is a convex surface and the other cylindrical surface is a convex or concave surface. In still another constitution, two semiconductor lasers emitting the same optical signal are arranged adjacent each other so that respective light emitting portions of two pn junction planes are located in the same plane and perpendicular to each other, and that laser beams form orthogonal spots at a single predetermined position.
A semiconductor laser light source unit for illuminating a remote light-receiving surface comprising a plurality of semiconductor lasers, each laser being contained in a separate package, the lasers being arranged adjacent to each other so as to emit light beams along the same axis toward the remote light-receiving surface and being oriented so that light emitting portions of respective pn junction planes are not parallel with each other and the light beams provide an illumination pattern on the light-receiving surface having improved angular uniformity, and wherein the semiconductor lasers emit respective laser beams carrying the same signal toward a single predetermined position at the remote light receiving surface.
Dependencies are inferred from the claim text.