Patent ID: 7554636

Claim:
A retardation control element, comprising: a light-transmitting base material; and a birefringence functional layer obtained by mutually crosslinking and polymerizing crosslinkable liquid crystal compounds coated directly or indirectly on the base material, wherein a maximum outer diameter of foreign matters present on a surface or inside of the birefringence functional layer is 7 μm or less, the number per unit area of the foreign matters having an outer diameter in the range of 0.2 to 2 μm is 15 pieces /mm 2 or less, the number per unit area of the foreign matters having an outer diameter in the range of 2 to 5 μm is 10 pieces/mm 2 or less, and the number per unit area of the foreign matters having an outer diameter in the range of 5 to 7 μm is 5 pieces/mm 2 or less.