Patent ID: 7102704

Claim:
A display for processing both external light and light emitted by a light-transmitting EL element, comprising: circularly polarizing means for selectively transmitting substantially circularly polarized light, either right or left, from the external light; the light-transmitting EL element; and a reflective display element behind the EL element, wherein the reflective display element is arranged to reflect the circularly polarized light in at least one of the external light and the light emitted by the EL element, wherein die display is operable in at least one mode to transmit the external light to the reflective display element, wherein the circularly polarizing means includes one polarizing plate and at least one wave plate, and wherein: the circularly polarizing means includes two optical phase difference compensating plates and is arranged from, listed as viewed from the EL element, a first optical phase difference compensating plate of which retardation in a normal direction to a substrate is set to not less than 100 nm and not more than 180 nm, a second optical phase difference compensating plate of which retardation in a normal direction to a substrate is set to not less than 200 nm and not more than 360 nm, and a linearly polarizing plate; and the polarizing plate and the optical phase difference compensating plates are positioned so as to satisfy 35°≦|2×θ2−θ1|≦55° where θ 1 is an angle between either a transmission axis or an absorption axis of the linearly polarizing plate and a retardation axis of the first optical phase difference compensating plate, and θ 2 is an angle between either a transmission axis or an absorption axis of the linearly polarizing plate and a retardation axis of the second optical phase difference compensating plate.