JPS5451729A - Maintenance pulse application method for el display unit - Google Patents

Abstract

PURPOSE:To secure an optical writing under the optimum conditions by setting the duration of the maintenance pulse at the optical writing time different from the pulse duration at the still picture display time. CONSTITUTION:Both the erase and write pulses are cut off with timing A, and only the maintenance pulse (solid lines) is applied. Thus, the subsequent pictures can be displayed in the form of the still pictures via the memory effect of EL. When the maintenance pulse is switched with timing B, the TV still picture is held as it is, and the optical images can be piled on through writing using the light pen or the projector. The maintenance pulse features a period of 1.59ms at the motion picture display time with the waveform to be applied to an optional picture element of the matrix panel. So is at the still picture display time in timing A. However, the piling of the optical images is impossible under these conditions, so the duration of the maintenence pulse is switched to TLS to perform an optical writing. In this case. the frequency of the maintenance pulse is reduced half (period 3.18ms) to lower the luminous intensity.