Barrier layer for thick film dielectric electroluminescent displays

A sub-structure of a thick film dielectric electroluminescent display, the sub-structure comprising, in sequence:

• a substrate;
• a lower electrode;
• a barrier layer;
• and
• a thick film dielectric layer,
• the barrier layer being chemically inert with respect to the lower electrode and the thick film dielectric layer, the barrier layer inhibiting diffusion of at least one chemical species therethrough.

A method for making a sub-structure for use in a thick film dielectric electroluminescent display, the method comprising;

• i) depositing a barrier layer onto a substrate;
• ii) depositing a lower electrode onto the barrier layer;
• and
• iii) depositing a thick film dielectric layer onto the lower electrode, the barrier layer being chemically inert with respect to the substrate and the lower electrode, the barrier layer inhibiting diffusion of at least one chemical species therethrough.

A method for making a sub-struc ture for use in a thick film dielectric electroluminescent display, the method comprising;

• i) depositing a lower electrode onto a substrate;
• ii) depositing a barrier layer onto the lower electrode;
• and
• iii) depositing a thick film dielectric layer onto the lower electrode, the barrier layer being chemically inert with respect to the lower electrode and the thick film dielectric layer, the barrier layer inhibiting diffusion of at least one chemical species therethrough.

A sub-structure of a thick film dielectric electroluminescent display, the sub-structure comprising, in sequence:

• a substrate;
• a barrier layer inhibiting diffusion of at least one chemical species therethrough;
• a lower electrode;
• and
• a composite thick film dielectric layer,
• the barrier layer being chemically inert with respect to the substrate and the lower electrode, the barrier layer having physical properties such that internal stress is minimized during fabrication of the sub-structure and the barrier layer and other layers of the sub-structure and display remain substantially crack-free.