Patent ID: 8139042

Claim:
An input device comprising: a light-transmissive touch panel, a phase difference plate disposed on the opposite side to an input operation surface of the touch panel, a ¼ wavelength plate disposed on the side of the input operation surface of the touch panel, and a polarizing plate on the touch panel side, which is disposed on the ¼ wavelength plate toward the input operation surface of the touch panel, wherein a ratio R 1 (450 nm)/R 1 (590 nm) of the phase difference value R 1 (450 nm) for the phase difference plate at a wavelength of 450 nm to the phase difference value R 1 (590 nm) for the phase difference plate at a wavelength of 590 nm is greater than a ratio R 0 (450 nm)/R 0 (590 nm) of the phase difference value R 0 (450 nm) for the ¼ wavelength plate at a wavelength of 450 nm to the phase difference value R 0 (590 nm) for the ¼ wavelength plate at a wavelength of 590 nm, the phase difference value R 1 (590 nm) for the phase difference plate at a wavelength of 590 nm is smaller than the phase difference value R 0 (590 nm) for the ¼ wavelength plate at a wavelength of 590 nm, and an absolute value of an angle between the retardation axis of the phase difference plate and the retardation axis of the ¼ wavelength plate is in the range of 60° to 85°.