Desiccant sealing arrangement for OLED devices
A method of encapsulating an OLED device, comprising: providing a substrate; forming an OLED device over the substrate, and a cover over the OLED device; and providing a desiccant sealing arrangement between the cover and the substrate, with the desiccant sealing arrangement provided by forming a perimeter seal and a spaced interior seal; a first desiccant material placed between the perimeter seal and the spaced interior seal; and a second desiccant material placed interior of the spaced interior seal.
1 . A method of encapsulating an OLED device, comprising:
(a) providing a substrate;
(b) forming an OLED device over the substrate, and a cover over the OLED device; and
(c) providing a desiccant sealing arrangement between the cover and the substrate, with the desiccant sealing arrangement provided by forming:
(i) a perimeter seal and a spaced interior seal;
(ii) a first desiccant material placed between the perimeter seal and the spaced interior seal; and
(iii) a second desiccant material placed interior of the spaced interior seal.
2 . The method of claim 1 wherein the substrate defines two coplanar surfaces.
3 . The method of claim 1 wherein the cover defines two coplanar surfaces.
4 . The method of claim 3 wherein the substrate defines two coplanar surfaces.
5 . The method of claim 1 wherein the first and second desiccant materials are particulate materials or particulate materials formed into a matrix.
6 . The method of claim 1 wherein the second desiccant material has an equilibrium humidity level less than 1000 ppm.
7 . The method of claim 6 wherein the first desiccant material has an equilibrium humidity level greater than 1000 ppm.
8 . The method of claim 1 further providing one or more thin-film encapsulation layers over the OLED device.
9 . The method of claim 1 wherein the cover is spaced from the OLED device and adhesive material is disposed between the OLED device and the cover.
10 . The method of claim 1 wherein perimeter seal or the spaced interior seal or both include a glass ledge.
11 . The method of claim 10 further providing that the distance between the first desiccant material and the substrate is less than the thickness of the perimeter seal to improve moisture absorption by the first desiccant material.
12 . The method of claim 1 further including selecting the seal widths based on the type of seals, the desiccant materials, and the desired moisture level in contact with the OLED device.