CPT is using a 0.5" 800x600 (SVGA) microdisplay with a display area of 10.13x7.61 mm. It simulates a 15" display from 2.5 meters. As far as I know OLighTEK (a Chinese-based OLED microdisplay maker) is the only company that ships 0.5" SVGA OLED microdisplays so it is likely that they are the display supplier. CPT is also developing AMOLED displays, but as far as I know they do not produce OLED microdisplays.
This technology is similar to Google's Glass HMD, which uses a Himax-made LCoS panel. In May 2013 it was reported that Google plans to use an OLED microdisplay in its next-gen consumer Google Glass edition and has contracted Samsung to develop the display. In July however, Himax announced that Google bought a 6.3% stake in the company. This probably signals that Google means to keep using Himax's based LCoS displays.