Stress-relieved electroluminescent panel

DETAILED DESCRIPTION A stress-relieved electroluminescent lamp includes an insulative or insulatively coated base having a portion thereof covered by a base electrode.
An electroluminescent layer overlays a portion of the base electrode and is covered by a transparent electrode.
In one embodiment, the base is a metal base and the insulative layer is greater than about 0.
005" thick.
The insulative layer has a bubble structure selected for adequate flexibility and contains a metal oxide to improve adhesion.
A base electrode covers the insulative layer and is formed from conventional deposition and photolithographic patterning.
A base dielectric formed from a glass selected to have a high adhesion covers the base electrode to act as a transitional layer for additional layers.
Next, the electroluminescent layer, deposited by electrophoresis or other conventional techniques, covers the base dielectric to provide a light-emissive material above the base electrode.
Together the electroluminescent layer and base dielectric form an insulative region above the base electrode with the thickness of about 0.
003".
A transparent cover electrode covers the electroluminescent layer above the base electrode.
The cover electrode is covered in turn by a passivation layer of a hermetic ceramic glass that covers the front face of the lamp and wraps around to cover at least a portion of the rear face.
Small gaps in the passivation layer allow electrical connection to the base and cover electrodes.
Because the base and cover electrodes are insulated from the base, the base can be grounded to provide shock protection and/or to allow a ground fault interrupt configuration.
Also, because the passivation layer covers both the front and rear surfaces of the sign, stress on the base due to differential thermal expansion is reduced.
The sign is therefore less likely to warp due to temperature swings.
Further, because the transparent cover electrode can be used as a reference electrode, the base electrode can be used as the "hot" electrode