Wave plate

A wavelength plate having the same polarizing characteristics against monochromic lights having a different wavelength, which is obtained by laminating a retardation film (A) that provides a retardation of (1+X)λ to light having a wavelength λ (nm) as defined according to the following expression (1) as an essential component and a retardation film (B) that provides a retardation of (¼+Y/2)λ or a retardation film (C) that provides a retardation of (½+Z)λ [wherein X, Y, and Z each independently represent 0 or an integer of 1 or more] such that an optical axis of the retardation film (B) or retardation film (C) intersects with an optical axis of the retardation film (A):

• [(λS+λL)/2]−200≦λ≦[(λS+λL)/2]+200 (1)
• λS:
• wavelength (nm) of monochromic light in the shortest wavelength side;
• and
• λL:
• wavelength (nm) of monochromic light in the longest wavelength side.