Projection lens and projection-type display apparatus

A projection lens consisting essentially of:

• a first lens group having positive refractive power;
• and
• a second lens group having positive refractive power in this order from a magnification side,
• wherein a surface closest to a reduction side in the first lens group is convex, and
• wherein the second lens group consists of two single lenses each having positive refractive power, and in each of which a surface having a smaller absolute value of a curvature radius faces the reduction side, and
• wherein the following conditional expressions (1) through (4) are satisfied:
• |R1b/R1f|≦0.5 (1);
• |R2b/R2f|≦0.6 (2);
• |Δ/f2|≦0.3 (3);
• and
• d2/f2≦0.4 (4), where
• R1b:
• a curvature radius of a reduction-side surface of the positive lens located toward the magnification side in the second lens group,
• R1f:
• a curvature radius of a magnification-side surface of the positive lens located toward the magnification side in the second lens group,
• R2b:
• a curvature radius of a reduction-side surface of the positive lens located toward the reduction side in the second lens group,
• R2f:
• a curvature radius of a magnification-side surface of the positive lens located toward the reduction side in the second lens group,
• Δ:
• a distance between a lens surface closest to the reduction side in the first lens group and a magnification-side focal position of the second lens group,
• f2:
• a focal length of the whole second lens group, and
• d2:
• the total length of the second lens group.