Patent ID: 7535166

Claim:
An organic EL display comprising: an organic EL element which comprises a first electrode, a second electrode facing the first electrode, and an active layer interposed between the first and second electrodes and including an emitting layer; and an outcoupling layer facing the first electrode, wherein the organic EL element forms a waveguide layer which includes the first electrode and the active layer and in which light components from the emitting layer propagate in an in-plane direction parallel to a main surface of the waveguide layer while causing multiple-beam interference, wherein a distance between the outcoupling layer and the waveguide layer is shorter than a wavelength of light from the organic EL element, and wherein a guide length x in μm calculated by using a following equation (1), a number of reflection m calculated by using a following equation (2), an absorption coefficient α in μm −1 of the waveguide layer, and an outcoupling efficiency β of the outcoupling layer satisfy a relationship represented by a following inequality (3), where L is a thickness in μm of the waveguide layer, θ i is an incident angle at which a light component with the highest intensity emitted by the emitting layer and propagating in the in-plane direction in the waveguide layer while causing multiple-beam interference is incident on a main surface of the waveguide layer facing the outcoupling layer, and the outcoupling efficiency β is a luminous energy ratio of a light component extracted from the waveguide layer with respect to an incident light for a single reflection of the light component with the highest intensity on the main surface of the waveguide layer facing the outcoupling layer, x = L cos ⁢ ⁢ θ i ( 1 ) m = 1 2 ⁢ ( ln ⁢ ⁢ 100 α ⁢ ⁢ x + 1 ) ( 2 ) β ⁢ ∑ M = 1 m ⁢ ⁢ ( 1 - β ) M - 1 exp ⁢ { α ⁡ ( 2 ⁢ M - 1 ) ⁢ x } > 0.1 . ( 3 )