Thin layer transistor (TFT) liquid crystal display and controller, sensor detects that vertical sync signal is not present during three identical periods of pre-sync signal

摘要

The displays time synchronization signal is a vertical synchronization signal. The pre-synchronization signal has the same frequency as the vertical synchronization signal. Determination of the presence of signal (28) produces a signal which does not indicate the input state of the vertical synchronizing signal when this signal is not entered in an identical fashion during three periods of the pre-synchronizing signal. Liquid crystal display including: (a) a liquid crystal screen (2) having pixel electrodes arranged in a matrix; a timing controller (34) for producing and outputting signals to control the screen in response to a synchronization timing signal input from the exterior and to reorganize and output input data; a control circuit connected between the screen and the sync timing controller (34) to display, input data from the timing controller (34), on the screen in response to the control signal; an oscillator (26), to produce pre-sync signals, having a suitable frequency for application to the timing controller (34); a signal presence sensor (28), for comparing the timing sync signal with the pre-sync signal, so as to produce a signal indicating the existence of an input signal from the timing sync signal; a control signal generator (30), producing a control signal on the base of the pre-sync signal in response to the signal indicating no input of the timing sync signal, and; a data memory storing certain image data and outputting the image data to a control circuit in response to a signal which indicates that the timing sync signal has not been input.