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.