TRANSPARENT MEMBER

PROBLEM TO BE SOLVED: To improve water repellency by a method in which the optical characteristics of a transparent member are kept, and the contact angle between the surface and a water droplet adherent to the surface is made greater than that between a conventional even surface and a water droplet. SOLUTION: Unevenness 13 is formed on the surface of a substrate 11 by etching. Since a water repellent monomolecular membrane 15 is formed on the unevenness 13, the surface of the membrane 15 is made uneven. When a water droplet 17 is put on the surface 15a of the membrane 15, the contact area between the surface 15a and the droplet 17 is decreased to increase the contact area between the droplet 17 and the air. Therefore, the droplet 17 becomes spherical due to surface tension to increase the contact angle θ. In a comparative example, since the surface 100 of a lens is not etched, the contact area between the surface 100 and the droplet 17 is much greater than that of an example so that the contact angle θx is smaller than the contact angle θof the example.