face plate or by applying opaque paint or ink thereto alternatively in the preferred practice where the face plate is a unitary structure formed by molding or casting a transparent resin the mold may have an area corresponding to the border and side edge which will impart a frosted finish to the resin referring to fig4 6 back plate 11 comprises a planar viewing area 17 which is transparent and a continuous tongue 18 extending forwardly substantially perpendicular to the back plate the planar back plate 11 has the same dimensions as the face plate and tongue 18 is spaced inwardly from the edge of back plate 11 a distance sufficient to provide a close mating engagement of tongue 18 in groove 15 around the entire periphery of the display frame when the face plate and back plate are placed in assembled relation as shown in fig6 the back plate is provided with an opaque border 19 which may be formed or applied in the same manner as described above for the border 16 of the face plate the border at the lower edge of back plate 11 is preferably much wider than the border around the other edges as shown at 19a.