| 摘要 |
PURPOSE:To facilitate manufacture and to improve yield by adhering a triangular prism made of a birefringent material to a cylindrical type distributed index lens in one body. CONSTITUTION:The cylindrical type distributed index lens 2 which has a slanting end surface conforming to the slanting surface of a triangular prism 1 made of a birefringent material is adhered to said triangular prism 1 with an adhesive 3. The refractive index of the cylindrical type distributed index lens 2 to an extraordinary light beam (e) is different according to the radial distance from the cylinder axis, and even if light is made incident slantingly to the cylinder axis, its light beam track is bent and the projection light is projected from the end surface of the cylindrical type distributed index lens 2 in parallel to the incident light. Thus, the cylindrical type distributed index lens 2 uses the transparent material such as glass, so the workability is excellent, the nonreflective coating of the end surface is facilitated, and only one triangular prism made of the birefringent material which is inexpensive and superior in workability is used; the yield is improved, the manufacture is facilitated, and the cost is reduced.
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