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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.

An ITO/BaTi03 /ZnS:Mn/black insulator/Al ac thin film electroluminescent display device with high display viewability has been developed for the application in the automotive dashboard display. The device consists of back and front insulating layers and a ZnS:Mn luminescent layer. The back insulating layer consists of the GaAs light absorption layer and the Hf O2 insulating layer. This device exhibits high contrast ratio (greater than 2:1) in an ambient illumination of 10,000 ft-candle at 125 ft-L brightness. This high contrast device also shows low power consumption due to placement of the black GaAs absorption layer between Hf O2 insulating layers in the back side. This is a significant improvement over previously published results. Detailed experimental results will be presented.

An at thin film electroluminescent display device with a structure of anti-reflection layer/glass/ITO/BaTiO3 /ZnS:Mn/black insulator/Al has been developed which is applicable as an automobile dashboard display. The device revealed high brightness and high contrast ratio which can be further improved by applying an anti-reflection coating (ARC) on the front glass surface. Under an ambient illumination of 10,000 ft-candle, with a brightness of 200 ft-L, the contrast ratio is 3.5 and increases to 4.5 when an anti-reflection coating is applied. There is a significant improvement compared to the formerly reported one (Contrast ratio = 2, brightness = 125 ft-L, under the same illumination).