Abstract: An imperforate display membrane is backlit by placing an apertured support between a light source and the display membrane so that light travels through the support and forms a spot on the membrane at a desired position having display indicia in registration therewith. One or more overlay members are provided and with said members having revised indicia thereon which either up-dates, corrects or otherwise revises the indicia on the original membrane. The membrane support and each overlay member are constructed to provide mutual magnetic attraction therebetween. Furthermore, each overlay member is provided with an opening which is adapted to register with the light aperture in the membrane support when the overlay member is magnetically held in place to the support and over the old indicia.

Abstract: An imperforate display membrane is backlit by placing an apertured support between a light source and the display membrane so that the light travels through the support and forms a spot on the membrane at a desired position having display indicia in registration therewith. When a plurality of interchangeable flexible display membranes are to be used, vacuum means are provided to hold the respective membrane in place. The vacuum is provided at the light transmission openings in the support and adjacent the display indicia. Additional vacuum openings may be disposed in the support and which are removed from the light transmission openings and registered indicia.