| 摘要 |
PROBLEM TO BE SOLVED: To optically scan with high accuracy without incurring high cost. SOLUTION: A coupling optical system 15 includes a first lens 15a made of glass having positive power and a second lens 15b made of resin having negative power. The first lens 15a has a flat incident face and a spherical emitting face, and the second lens 15b has a cross section which has a non-arctic shape in direction corresponding to a main scanning on an emitting face. In this case, the first lens 15a has a simple surface shape, so that the lens is easily and accurately machined even though the lens is made of glass. Further, the second lens 15b, which is made of resin, is easily and accurately manufactured by a conventional forming method (an injection molding or the like) at low cost even though the lens has a complicated surface shape. Accordingly, inexpensive and accurate lenses can be used both for the first lens 15a and the second lens 15b. COPYRIGHT: (C)2009,JPO&INPIT
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