Patent ID: 7158319

Claim:
An imaging lens system used for forming an image of an object on an image taking surface of a solid image sensor element, comprising: in order from an object side towards an image surface side, a diaphragm, a first lens which is a meniscus lens having a positive power whose concave surface facing said object side, and a second lens which is a meniscus lens having a negative power whose convex surface facing said image surface side, wherein conditions expressed by each of following expressions (1)–(8) are to be satisfied; 1.65≧ L/fl≧ 0.9 (1) −0.4≧ f 1 /f 2 ≧−0.7 (2) 0.63≧ f 1 /fl≧ 0.4 (3) −0.85≧ f 2 /fl≧− 1.15 (4) 0.65≧ d 2 /d 1 ≧0.35 (5) 4≧ fl≧ 1 (6) −1.5>( r 3 +r 4 )/( r 3 −r 4 )>−2 (7) 0.45≧ d 1 /fl≧ 0.25 (8) where, L: entire length of said lens system (distance between said diaphragm and said image taking surface on an optical axis) fl: focal distance of entire lens system f 1 : focal distance of said first lens f 2 : focal distance of said second lens d 1 : center thickness of said first lens d 2 : distance between said first lens and said second lens on said optical axis r 3 : curvature radius of said object side face of said second lens r 4 : curvature radius of said image surface side face of said second lens.