Thin film electroluminescence device

• US 4,717,858 A
• Filed: 01/15/1986
• Issued: 01/05/1988
• Est. Priority Date: 01/22/1985
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Tanaka, Koichi, Ogura, Takashi, Ianiguchi, Koji, Mikami, Akiyoshi, Yoshida, Masaru
• Primary Examiner(s): DEMEO, PALMER
• Application Number:
  US06/819,217
• Time in Patent Office: 720 Days
• Field of Search: 313/503, 313/509
• US Class Current: 313/503
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers

Abstract

A thin film electroluminescence device comprising an electrode layer, an emitting layer and an electrode layer formed on a substrate one over another, and an insulating layer optionally interposed between the three layers, the emitting layer being made of CaS serving as a host material and doped with Eu²⁺ providing luminescent centers.

The emitting layer comprising a novel combination of host material and luminescent center produces a red electroluminescence with a high brightness.

Claims

1. A thin film electroluminescene device comprising an electrode layer, an emitting layer and an electrode layer formed on a substrate one over another, and an insulating layer interposed between the three layers, the emitting layer being made of CaS serving as host material and doped with Eu²⁺ providing luminescent centers, said host material being doped with 0.05 to 0.8 atm. percent of Eu²⁺ and being oriented in a direction of the (222) axis.

2. A device as defined in claim 1 wherein the insulating layer is formed of a nitride over the region thereof in contact with the emitting layer.

3. A device as defined in claim 2 wherein the nitride is Si₃ N₄, AlN or BN.