Method of making two dimensional organic light emitting diode array for high density information image manifestation apparatus

• US 5,656,508 A
• Filed: 07/22/1996
• Issued: 08/12/1997
• Est. Priority Date: 03/22/1995
• Status: Expired due to Term

• Current Assignee: Universal Display Corporation
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: So, Franky, Harvey, Thomas B. III, Shi, Song Q.
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): MULPURI, SAVITRI
• Application Number:
  US08/684,779
• Time in Patent Office: 386 Days
• Field of Search: 437/1, 437/3, 437/5, 437/23, 437/127, 437/129, 437/203, 437/89, 437/90, 437/128, 257/40, 257/80, 257/81, 257/88, 257/10
• US Class Current: 438/34
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 59/17 Passive-matrix OLED displays

Abstract

A two dimensional array of organic LEDs including laterally spaced, conductive strips positioned on an insulative substrate with a layer of dielectric material positioned thereon and defining cavities therethrough so as to expose areas of the conductive strips within the cavities. At least a layer of active emitter material and a layer of a low work function metal are positioned in each of the cavities on the conductive strips so as to form an LED in each cavity with the conductive strips forming a first electrode of each LED. A layer of metal is sealing positioned over each of the cavities and formed into metallic strips orthogonal to the conductive strips so as to form a second electrode for each of the LEDs.

Claims

1. A method of fabricating a two-dimensional organic light emitting diode array for high density information image manifestation apparatus comprising:

providing an electrically insulative substrate with a planar surface;

depositing a layer of electrically conductive material on the planar surface of the substrate;

patterning the layer of electrically conductive material to form a plurality of laterally spaced, conductive strips defining first electrodes;

depositing a layer of dielectric medium on a surface of the conductive strips and the planar surface of the substrate;

depositing a layer of photoresist on the layer of dielectric medium;

patterning the photoresist using a cavity defining mask to expose portions of the dielectric medium;

etching away the exposed portions of the dielectric medium to form a plurality of laterally spaced cavities, each of the plurality of cavities being positioned on an associated one of the defined first electrodes and exposing therein the associated first electrode;

striping off the photoresist;

depositing in each of the cavities an electroluminescent medium in the successive order of a layer of hole transporting material, a layer of active organic emitter, a layer of electron transporting material and a layer of a low work functional metal;

depositing a layer of ambient stable metal on the dielectric medium so as to sealingly overlie each of the cavities and electrically contact the layer of low work function metal in the cavities; and

patterning the layer of ambient stable metal into metal strips in a direction orthogonal to the conductive strips so as to define second electrodes sealing each of the plurality of cavities.

2. A method of fabricating a two-dimensional organic light emitting diode array for high density information image manifestation apparatus as claimed in claim 1 wherein the step of providing a substrate includes providing a substrate that is light transmissive.

3. A method of fabricating a two-dimensional organic light emitting diode array for high density information image manifestation apparatus as claimed in claim 1 wherein the step of depositing a layer of electrically conductive material on the upper surface of the substrate includes depositing a layer of material that is also light transmissive.

4. A method of fabricating a two-dimensional organic light emitting diode array for high density information image manifestation apparatus as claimed in claim 1 wherein the step of depositing in each of the cavities an electroluminescent medium includes depositing the medium by one of the following methods:

sputtering, thermal evaporating, injection-filling, spin-coating, roll-coating, dip-coating or doctor-blading.

5. A method of fabricating a two-dimensional organic light emitting diode array for high density information image manifestation apparatus including the steps of:

providing a light transmissive, electrically insulative substrate with a planar surface;

depositing a layer of light transmissive, electrically conductive material on the planar surface of the substrate;

patterning the layer of conductive material to form a plurality of laterally spaced apart, parallel conductive strips defining first electrodes;

depositing a layer of dielectric medium on an upper surface of the conductive strips and the planar surface of the substrate;

spin-coating a layer of photoresist on the layer of dielectric medium;

patterning the photoresist using a cavity defining mask to expose portions of the layer of dielectric medium;

etching away the exposed portions of the dielectric medium to form a plurality of laterally spaced cavities, one each of the plurality of cavities being positioned on an associated electrode of the first electrodes and exposing a surface of the associated electrode;

striping off the photoresist;

depositing within each of the plurality of cavities an electroluminescent medium in the successive order of a layer of hole transporting material, a layer of active organic emitter, a layer of electron transporting material and a layer of a low work functional metal;

depositing a layer of ambient stable metal on the dielectric medium so as to sealingly cover the cavities; and

patterning the layer of ambient stable metal into metal strips extending in a direction orthogonal to the conductive strips and sealingly engaged with the plurality of cavities and electrically engaged with the low work function metal in the cavities.

6. A method of fabricating a two-dimensional organic light emitting diode array for high density information image manifestation apparatus characterized by:

providing an electrically insulative substrate with a planar surface;

depositing and patterning layer of electrically conductive material on the planar surface of the substrate so as to form a plurality of laterally spaced, conductive strips defining first electrodes on the substrate;

depositing a layer of dielectric medium on a surface of the conductive strips and the planar surface of the substrate;

patterning the layer of dielectric material to define a plurality of laterally spaced cavities therethrough, each of the plurality of cavities being positioned on an associated one of the defined first electrodes and exposing therein a portion of the associated first electrode;

depositing on the exposed portion of the associated first electrode in each of the cavities an electroluminescent medium including an active organic emitter and a layer of a low work function metal; and

depositing and patterning layer of ambient stable metal on the dielectric medium so as to sealingly overlie each of the cavities and electrically contact the layer of low work function metal, the layer of ambient stable metal defining laterally spaced apart metal strips extending in a direction orthogonal to the conductive strips so as to define second electrodes sealing each of the plurality of cavities.