The general field of the invention is that of the display devices that comprise an active liquid crystal matrix of twisted nematic type. The matrix comprises a set of pixels, a set of rows and of columns and an electronic control device. Each pixel is controlled by a transistor. The voltage applied to each control row is either a switch-on voltage VG_on sufficient to switch on the transistors, or a switch-off voltage VG_off sufficient to switch off the transistors. The voltage applied GMA to each column is dependent on the predetermined optical transmission of the pixel. The display device comprises means for detecting the correct operation of the electronic control device. In case of detection of incorrect operation, the display device comprises cut-off means arranged to force to zero the switch-off voltages VG_off of the rows and the GMA voltages of the columns, so that the transmission of all the pixels of the first set is minimum.