| 摘要 |
A subject for the invention is to provide a lens which is lightweight and inexpensive and, despite this, which is large and has a high-precision aspherical reflecting surface reduced in distortion. The invention provides: a projection lens comprising a resin base having a given curved surface and a reflecting layer formed over the surface of the resin base, characterized in that the average of in-plane birefringent phase differences per unit thickness as measured with incident light from the direction perpendicular to the curved optical functional surface of the resin base is 30 nm/mm or less in a region accounting for at least 60% of the area of the optical functional surface; or a projection lens having a reflecting layer on an optical-function-imparted surface, wherein at least 60% of the optical-function-imparted surface has a surface roughness (Ra) of 200 Å or lower.
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