Patent ID: 8487335

Claim:
A light emitting device comprising: an organic layer sandwiched between a first electrode and a second electrode to serve as an organic layer including a light emitting layer for emitting monochromatic light at one location; a first light reflection boundary face provided on a side close to said first electrode to serve as a boundary face for reflecting light emitted from said light emitting layer so as to radiate said reflected light from a side close to said second electrode; and a second light reflection boundary face, a third light reflection boundary face and a fourth light reflection boundary face which are sequentially provided at positions separated away from each other in a direction from said first electrode to said second electrode on said side close to said second electrode, wherein with notation L 1 denoting an optical distance between said first light reflection boundary face and the luminescence center of said light emitting layer, with notation L 2 denoting an optical distance between said luminescence center and said second light reflection boundary face, with notation L 3 denoting an optical distance between said luminescence center and said third light reflection boundary face, with notation L 4 denoting an optical distance between said luminescence center and said fourth light reflection boundary face, with notation λ 1 denoting the center wavelength of a light emission spectrum of said light emitting layer, with notations n, m, m′ and m″ each denoting an integer, with notations λ 11 , λ 12 , λ 13 and λ 14 each denoting an interference wavelength, with the length unit nanometer taken as a unit of said wavelengths λ 1 , λ 11 , λ 12 , λ 13 and λ 14 , with notation φ 1 denoting a phase change observed when light having wavelengths is reflected by said first light reflection boundary face, with notation φ 2 denoting a phase change observed when light having wavelengths is reflected by said second light reflection boundary face, with notation φ 3 denoting a phase change observed when light having wavelengths is reflected by said third light reflection boundary face, and with notation φ 4 denoting a phase change observed when light having wavelengths is reflected by said fourth light reflection boundary face, said optical distances L 1 , L 2 , L 3 and L 4 satisfy all Expressions (1) to (8) given as follows: where n ≧0, 2 L 1/λ11+φ1/2π =n (1) λ1−150<λ11<λ1+80 (2) 2 L 2/λ12+φ2/2 π=m (3) 2 L 3/λ13+φ3/2 π=m′+ 1/2 (4) 2 L 4/λ14+φ4/2 π=m″+ 1/2 (5) λ1−80<λ12<λ1+80 (6) λ1−150<λ13<λ1+150 (7) λ1−150<λ14<λ1+150 (8).