| 摘要 |
In an optical scanner, coupling lens system 3 includes a first optical element as at least one optical element other than the optical element located the farthest away from a light source, the first optical element being made of a material having substantially no power and a negative temperature coefficient of refractive power, and scanning lens system 5 includes at least one second optical element made of a material having positive power and a negative temperature coefficient of refractive index.
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