Patent ID: 6600527
Filing Date: 2003-07-29
Classification: G02F,G04G

Abstract:
Display assembly including two superposed, respectively upper and lower display devices, characterised in that the upper display device includes a double structure formed of a display cell arranged above an optical valve, said double structure being arranged so that said cell and said valve are transparent in a first state to make the lower display device visible, and that the cell displays an item of data and that the valve is opaque and masks at least partially the lower display device in a second state, control means being provided for supplying a control voltage to the cell and the optical valve to cause them to switch from the first state to the second state and vice versa, wherein the optical valve is formed of a twisted nematic cell, a linear polariser placed in front of the cell, a quarter-wave plate and a cholesteric film having a first helical direction placed in succession behind the cell.