| 摘要 |
PROBLEM TO BE SOLVED: To provide a light collection optical system which offers both compactness and a wide view angle, as well as minimized aberrations including field curvature.SOLUTION: A light collection optical system has a lens configuration comprising a first group having positive power and a second group having positive power arranged in order from a point light source side. The first group comprises in order from the point light source side; a meniscus lens having a concave surface on the point light source side; a positive lens having a convex surface on an observed object side; a positive lens having a convex surface on the point light source side; a negative lens having a concave surface on the observed object side; a cemented lens having a concave surface on the point light source side and a convex surface on the observed object side and comprising a negative lens and a positive lens; and a positive lens having a convex surface on the observed object side. The second group comprises in order from the point light source side; a positive lens having a convex surface on the point light source side; a cemented lens comprising a negative lens and a positive lens; a positive lens; and a meniscus lens having a concave surface on the observed object side. Surface shape of the meniscus lens of each group satisfies predetermined conditions. |
