Indicating device for illustrating symbols of all kinds

Abstract

An indicating device for projecting symbols of all kinds characterized by a plate of fluorescent synthetic material having metallized edges to create a light trap for the fluorescent light created in the plate, a layer of light dispersing material mounted in spaced relation to a surface of the plate, contact film disposed at least in selected areas between the layer and plate, means for selectively moving portions of the layer into optical contact with the contact film and plate to cause decoupling of the fluorescent light from the plate. The means for moving includes a plurality of electrodes disposed in the device in a given pattern and means for selectively applying an electrical current to the electrodes to create a selective arrangement of electrical fields to create a display of a desired symbol. The means for moving may be a membrane on which electrodes are disposed to coact with electrodes on the plate to deflect the membrane toward the plate to move the dispersing layer into optical contact with the plate or may be a ceramic plate of ferroelectric material which on the application of electrical current to the electrodes causes a selected expansion of the plate due to remanent electrical polarization to move the layer into contact with the plate of fluorescent synthetic material.