| 摘要 |
A display or writing slate capable of producing luminescent images upon the application of pressure thereon which can be readily erased and repeatedly used that includes a pair of over-lying sheets, one of which is translucent or transparent, containing a luminescent dye or pigment and the other of which is opaque, and which sheets have a smooth surface at their interface. At least one of the sheets is formed of a pliable plastic with its interface surface tending to adhere to the interfacing surface of the other sheet when a pressure is applied thereto to produce the luminescent images. The improvement resides in the incorporation of a non-migrating dye or pigment in the translucent or transparent sheet so as to resist the migration of the luminescent dye or pigment from the translucent or transparent sheet to the interface surface of the other sheet.
|
