The invention relates to an electroluminescent display, illumination or indicating device and to its fabrication process. This device (1) comprises a substrate (2) coated with an electroluminescent unit (3) having two electrodes, namely an internal electrode (5) and an external electrode (6), between which a light-emitting structure (4) is placed, at least one of said electrodes being transparent to the emitted light, a protective plate (7) being assembled on the unit by means of an adhesive (7a). According to the invention, this adhesive covers an adhesion-promoter layer (10) which surmounts the unit, being deposited by ALD (atomic layer deposition) from precursors, and which is based on at least one inorganic compound compatible with the adhesive, a metallic reactive sublayer (9) capable of reacting with at least one of these precursors being inserted beneath and in contact with this adhesion-promoter layer, at least one dielectric intermediate layer (8) transparent to the emitted light being placed between the external electrode and the reactive sublayer in order to form, with said external electrode and said reactive sublayer, a resonant cavity.