To prevent the loss of light in a light shielding part in a liquid crystal light bulb and in a projection lens of a projection liquid crystal projector so as to improve light efficiency by specifying a difference between a radius of curvature in the lateral direction of a micro lens and that in the diagonal direction to a specific value.
On a transparent base board 11, a transparent resin layer 12 is formed by spin coating. Then, a positive photosensitive resin layer with improved heat flowability is formed by spin coating, and a square pattern arranged two-dimensionally is formed by photolithography. The photosensitive resin is heated and melted by a hot plate so as to cause a heat flow, and a convex micro lens 23 is formed. In this process, the adjacent micro lenses 23 are connected together as the pattern flows on the base board 11. In the micro lens 23, a difference between a radius of curvature in the lateral direction and that in the diagonal direction is 35% or less. An occupying area ratio (micro lens area/base board area) is 95% or more.
ISHIMATSU TADASHI
KITAMURA TOMOHITO
Next Patent: MICROLENS SHEET AND VIDEO PRINTER USING SAME