Chinese display makers CSOT, Tianma and Visionox have together joined BOE to file a trial for patent invalidation with the Patent Trial and Appeal Board (PTAB), according to news on June 18. The four Chinese display manufacturers are specifically attacking one patented technology--Organic Light Emitting Display (OLED) Device Pixel Circuit and Driving Method-- owned by Samsung Display. This is one of the patents Samsung Display included in its investigation with the US International Trade Commission(ITC) in December when the company fought against imports of OLED panels that infringe on its patents and technologies, the report said.