Organic EL element and method of forming the same

• US 20050134174A1
• Filed: 12/16/2004
• Published: 06/23/2005
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Tohoku Pioneer Company Limited (Pioneer Corporation)
• Original Assignee: Tohoku Pioneer Company Limited (Pioneer Corporation)
• Inventors: Fukuda, Yoshinori, Saso, Yasuhiro, Fujimura, Soh, Shiratori, Masahiro
• Granted Patent: US 7,301,278 B2
• Time in Patent Office: Days
• US Class Current: 313/506
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 59/32 Stacked devices having two or more layers, each emitting at different wavelengths
• CPC Class Codes: H10K 85/311 Phthalocyanine
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
• CPC Class Codes: H10K 85/649 Aromatic compounds comprising a hetero atom

Abstract

An organic EL element includes a plurality of light-emitting units which exhibit organic EL luminescence and at least two different luminous colors and are connected in series; and a light-emitting surface formed by overlapping partly or wholly light-emitting surfaces of the light-emitting units. The plurality of light-emitting units includes light-emitting units which exhibit one color and are formed in multiple stages. A desired mixed color is obtained from the light-emitting surface by combining the different luminous colors.

Claims

1. An organic EL element comprising:

a plurality of light-emitting units which exhibit organic EL luminescence and at least two different luminous colors and are connected in series; and

a light-emitting surface formed by overlapping partly or wholly light-emitting surfaces of the light-emitting units,

wherein the plurality of light-emitting units comprise light-emitting units which exhibit one color and are formed in multiple stages, and a desired mixed color is obtained from the light-emitting surface by combining the different luminous colors.

2. The organic EL element according to claim 1, wherein the plurality of light-emitting units comprise fluorescent light-emitting units and at least one phosphorescent light-emitting unit, wherein the fluorescent light-emitting units are formed in multiple stages with respect to the phosphorescent light-emitting unit.

3. The organic EL element according to claim 1, wherein the desired mixed color is white.

4. A method of forming an organic EL element including a plurality of light-emitting units exhibiting organic EL luminescence and at least two different luminous colors, comprising:

connecting the plurality of light-emitting units in series; and

overlapping partly or wholly light-emitting surfaces of the light-emitting units to form a light-emitting surface of the organic EL element,

wherein the plurality of light-emitting units comprise light-emitting units which exhibit one color and are formed in multiple stages, and a desired mixed color is obtained from the light-emitting surface of the organic EL element by combining the different luminous colors.

5. The method according to claim 4, wherein the number of multiple stages is obtained based on a current-luminance efficiency of each of the light-emitting units exhibiting different luminous colors and a required luminance mixingratio for obtaining the desired mixed color from the different colors.

6. The method according to claim 4, wherein the plurality of light-emitting units include fluorescent light-emitting units and at least one phosphorescent light-emitting unit, wherein the fluorescent light-emitting units are formed in multiple stages with respect to the phosphorescent light-emitting unit.

7. The method according to claims 4, wherein the desired mixed color is white.

8. An organic EL element comprising:

a plurality of light-emitting units which are connected in series, exhibit organic EL luminescence and at least two different color and include a first light-emitting unit exhibiting a first luminous color and a second light-emitting unit exhibiting a second luminous color; and

a light-emitting surface formed by overlapping partly or wholly light-emitting surfaces of the light-emitting units,

wherein a plurality of first light-emitting units are formed in multiple stages and a desired mixed color is obtained from the light-emitting surface by combining the first and second luminous colors.