Claims
- 1. A method for depositing two or more emission layers in a white light emitting OLED device wherein each emission layer is formed by the steps comprising:
(a) providing a solid compacted pellet of organic material including a mixture of at least one organic host and one organic dopant; (b) placing such a solid compacted pellet of organic material inside a receptacle disposed in a physical vapor deposition chamber; (c) positioning a substrate of a partially formed OLED device in the physical vapor deposition chamber in a spaced relationship with respect to the receptacle; (d) evacuating the chamber to a reduced pressure; and (e) applying heat to a surface of the solid compacted pellet of organic material disposed in the receptacle to cause at least a portion to sublime to provide a mixture of vapors of the organic materials including the host and the dopant to form an emission layer on the substrate.
- 2. The method of claim 1 wherein there are two emission layers which emit yellow and blue light.
- 3. The method of claim 1 wherein there are three emission layers which emit yellow, blue and green light.
- 4. The method of claim 1 wherein the compacted pellets of organic material are formed, comprising the steps of:
(a) providing a sublimable organic material in a powder form; (b) forming a mixture of the sublimable organic material comprising at least one organic host and one organic donor material; (c) placing such mixture in a die and using two opposing punches to supply sufficient pressure to the mixture; (d) applying heat to the die during or prior to applying pressure by the opposing punches to aid in the mixture of organic powders to consolidate into a solid pellet; and (e) removing the pellet from the die.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Reference is made to commonly assigned U.S. patent application Ser. No. 09/898,369 filed Jul. 3, 2001 entitled “Method of Compacting Organic Material in Making An Organic Light-Emitting Device” by Van Slyke et al; U.S. patent application Ser. No. 10/073,690 filed Feb. 11, 2002, entitled “Using Organic Materials in Making An Organic Light-Emitting Device” by Ghosh et al, and U.S. patent application Ser. No. 10/195,947 filed Jul. 16, 2002, entitled “Compacting Moisture-Sensitive Organic Material in Making An Organic Light-Emitting Device” by Ghosh et al, the teachings of which are incorporated herein.