The European Patent Office (EPO) ruled to upheld one of Universal Display's key PHOLED patents (EPO#EP1394870). This patent, which UDC refers to as EP870, details an OLED in which the emissive layer contains phosphorescent dopant compounds. This patent corresponds to the company's US'238 patent.
In November 2013, the Japanese High Court decided to validate UDC's claims in Japanese patent #4511024, which is a counterpart patent to the EP870 and US238 patents. Later in November, The EPO revoked one of UDC's basic phosphorescent OLED patents, EPO#1449238. The opposing parties included Sumitomo Chemical, Merck and BASF.
Disclosure: the author of this post holds shares in universal display