Abstract: A thin-film electroluminescent panel which has a light sink layer deposited immediately behind the phosphor layer thereof is modified to have a light emission enhancing dielectric layer deposited between the phosphor layer and the light sink layer. The light emission enhancing dielectricphosphor interface provides for injecting hot electrons for impact-exciting the luminescent centers in the phosphor to enable the panel to generate light when the front electrode of the panel is positive in potential. Moreover, the light emission enhancing dielectric layer is formed of a material having the same index of refraction as the phosphor layer so that it will pass the incident ambient light and the rearwardly directed light generated in the phosphor layer without reflection into the light sink layer wherein it is trapped by internal reflection and absorbed.

Abstract: A thin-film electroluminescent (EL) panel operating as a matrix-addressed display is provided with a light sink layer immediately behind the phosphor layer thereof to enhance the legibility of the display under high ambient light conditions. The light sink layer is formed of a p-type semiconductor compound material comprised of 20% lead telluride and 80% cadmium telluride doped with indium. The addition of the indium into the material introduces free electrons which compensate for the hole carriers therein and thereby increases the specific resistivity of the material. The addition of lead into the semiconductor compound material forms the lead telluride which in combination with the cadmium telluride reduces the energy band gap of the material to effectively absorb the ambient light in the visible range which is the source of the bad legibility. Moreover, the lead serves to reduce the mobility of the free charge carriers in the material and thereby further increases the specific resistivity of the material.

Abstract: An electroluminescent panel is provided for displaying a simulation of a speedometer for a vehicle. The simulation includes a rotating needle for indicating the speed of the vehicle and a drum type odometer for keeping track of the total mileage of travel of the vehicle. The electroluminescent panel has a microcomputer and a video ram associated therewith. On successive (Direct Memory Access) DMA periods of a millisecond operating cycle, the microcomputer is programmed to read columns of data out of the video ram to be displayed as corresponding columns of pixels on the electroluminescent panel. Between the successive Direct Memory Access periods of the millisecond operating cycle, the microcomputer is programmed to execute needle control and odometer control routines to update the data in the video ram in response to an input fed to the microcomputer indicative of the speed of the vehicle upon which the electroluminescent panel is mounted.

Abstract: A plurality of memory sections is provided each storing binary data to be employed for refreshing picture elements of a thin-film EL matrix display panel on successive frame time periods constituting an integration time period. The number of frame time periods in an integration time period corresponds to the number of different shades to be displayed on the panel. The binary data stored in each of the memory sections differs. Thus, when the binary data in the memory sections are read out on successive frame time periods, some of the picture elements on the panel are refreshed more than others during the integration time period. Accordingly, the eye of the viewer receives more light from some picture elements than others during each integration time period which results in the relative brightness levels and, therefore, the shades of the picture elements to vary.