Cambridge Display Technology (CDT)  and Toppan Printing, of Tokyo, Japan, have produced a number of 5.5 inch full colour active matrix polymer OLED (P-OLED) displays using a roll printing method. A demonstrator will be shown at the SID conference in San Francisco. The displays -- believed to be the first of their type ever produced -- are the result of close co-operation between the two companies and part of their joint development activity announced in February 2005.
Solution processing of P-OLED displays is more commonly associated with inkjet printing, and the companies believe that roll printing represents a promising alternative production technique, which offers the potential for very good display uniformity, very high display resolution and low capital and operating costs. In the future, this type of roll printing process could be well suited for making flexible P-OLED displays. CDT believes that this combination of properties can only be achieved with solution-based printing processes.
The technique is based on relief printing, a well-established method for the transfer of soluble materials onto a range of substrates, but which has been developed by Toppan into a highly precise technology capable of producing patterned pixels of small size and highly uniform distribution. The companies believe that the process is capable of scaling to large substrate size and very high resolution, potentially over 200 ppi.