Thin Film A.C. Electroluminescence for Automobile Instruments

A high brightness low a.c. voltage driven thin film electroluminescent display device has developed for applications in automotive dashboard displays.

The structure of a device is a double insulating layer structure and the maximum area of display panel can be made up to 140 × 170 mm², which is large enough to cover all required functions for automotive displays.

Two different types of devices which consist of ZnS:Mn and ZnS:TbF₃ are developed, and they emit orange and green color respectively. Their brightness under the operating condition of 80 volts, 1KHz sinusoidal excitation are 250 fL and 85 fL respectively. These devices have long life which is more than 20, 000 hours under normal conditions. Detailed experimental results will be presented.