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Method for manufacturing an improved cathode to cathode-lead contact in an organic electroluminescent device.

IP.com Disclosure Number: IPCOM000006811D
Publication Date: 2002-Feb-04
Document File: 4 page(s) / 233K

Publishing Venue

The IP.com Prior Art Database

Abstract

ID606464

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 50% of the total text.

Method for manufacturing an improved cathode to cathode-lead contact in an organic

electroluminescent device

This disclosure relates to an organic electroluminescent device. The basic

structure of these devices is a light emissive organic layer sandwiched between an

anode layer and a cathode layer, respectively. The figure shows the cross-sectional

structure of a typical organic electroluminescent (EL) device. Said device is typically

fabricated on a transparent substrate, such as glass, which is coated with a transparent

first electrode, such as indium-tin-oxide (ITO). This ITO coated substrate is covered

with at least a layer of an organic electroluminescent material and a final layer

forming a second electrode, which is typically a metal or alloy. Other layers maybe

added to the device, for example to improve charge transport between the electrodes

and the electroluminescent material.

Typically the substrate further comprises leads for making contact to the

cathode(s) of the device(s) on the substrate. These leads are made up from a material

having a low electrical resistivity, such as a metal or alloy.

During the production process, an electrical contact between the leads on the

substrate and the cathode has to be created by making vias in the organic material.

These vias are created by a dry etching technique, such as laser ablation. Presently,

these vias are ablated down to the lead metal. Subsequently, the second electrode

material (cathode) is deposited by vapour deposition on top of the layer(s) of organic

material. Said second electrode material also fills up the vias and establishes an

electrical contact between the cathode and the cathode lead.

It was found that a better and more stable contact between the cathode material

and the cathode lead can be established when the cathode leads are made-up from a

layer ITO on top of the substrate, which is covered by a layer of lead metal. During the

production process, the vias must be ablated down to the ITO layer which is in

electrical contact with the cathode lead. Subsequently, the second electrode material

(cathode) is deposited as described above, which material fills up the vias and

establishes an improved electrical contact between the cathode and the cathode lead

via the ITO layer.

cathod

device

cathod

device

Cross section of current situation

Organic

material^

layers

ITO"" t: *3tesS' substrate

Cross section of improved contact

H.P. van Broekhuyzen

Improved configuration of an energy recovery circuit

1. Introduction

Electroluminescent displays (EL displays) and other types like plasma displays form a

capacitive load for the drivers. Due to the combination of high driving voltages (in the

order of magnitude of 200V), and a high frequency (of 10 kHz to more than 100 kHz),

the power losses caused by charging and discharging the capacitive load is quite high.

By using resonant circuits, the...