The primary objective of this 18-month project is to develop a reliable, cost effective fabrication process for low power, low cost colour active matrix OLED-on-silicon micro-displays based on novel photo-patternable organic light emitting diode (p-OLED) RGB emitter materials. Due to the photo-patternability of the new p-OLED materials, conventional photolithography technique can be employed so that pixelated RGB emitters can be directly patterned. The unique feature of the p-OLED emitter system is that once it undergoes the UV cross-linking process, the polymer layer becomes insoluble and remains stable upon further processing. This is the basis for the fabrication of full colour PHOTOLEDD micro-displays without the need for colour filters as found in most conventional displays. This development will not only enable a 2D display with high brightness and efficiency to be produced, but also a novel stereoscopic 3D binocular display, the latter being based on polarised emission of the red, green and blue (RGB) light from a single p-OLED device. The novel 3D technology, which will be developed by Hull University and CRL Opto.
To ensure a successful outcome of this project, a second approach known as "Colour by Blue" will be developed by Opsys. Instead of incorporating all the RGB emitters on the same substrate as in Hull's case, Opsys has adopted a lower risk approach with the blue emitter layer on one substrate and the photoptternable photoluminescent materials with red/green emission on the other substrate. Both of the approaches described above are in principle, able to produce 2D as well as the unique stereoscopic 3D displays. The target for the 2D p-OLED materials is 15 lm/W and the target for the 3D p-OLED materials is 7 lm/W (both measured for green emission).
The 18-month work programme is divided into two main research areas:
1) New photopatternable OLED materials with high luminescence efficiency for the respective 2D and polarised light emitting 3D devices will be developed by Opsys, Hull and DSM. Novel photopatternable orientation layers based on liquid crystalline polymers will also be made as part of the polarised p-OLED material system for the stereoscopic 3D device. Evaluation of these new material systems will be based on single pixel p-OLED test devices (both ITO glass substrates and silicon backplane substrates). Ample quantities of the optimised materials will be made for subsequent fabrication of the PHOTOLEDD devices.
2) Design and optimisation of PHOTOLEDD device structures on silicon backplane will be developed by Opsys, Hull and CRL Opto. Optimisation of top electrode structure and lifetime studies of the basic device structures will form part of this development. Together with the developed p-OLED materials, this work package will enable the fabrication of the test silicon backplane displays, thus providing the basis for further development of the full colour, high resolution PHOTOLEDD p-OLED micro-displays in a subsequent project. Analogue, digital and biased drive schemes will also be investigated to see which is the most appropriate for driving the 2D and 3D PHOTOLEDD materials. To reduce risk and cost, an existing test silicon design developed previously by CRL Opto will be made available to this project.
Finally, exploitation will be through a second 18-month project to build micro-displays based on this technology which will involve all the partners who have been chosen to establish the whole supply chain, from materials supply to end user.
There will be two sets of main deliverables for this project as described below:
- Month 12: Demonstrate the basic process steps for the PHOTOLEDD technology by fabrication of the first monochrome single pixel test silicon device with a transparent top electrode
- Month 18: Demonstrate the feasibility of the colour PHOTOLEDD technology by fabrication of the RGB test silicon device with luminance efficiency of >15 lm/W and >7 lm/W for the 2D and 3D p-OLED materials respectively. A successful outcome of this project will pave the way for a follow up EU project, which is to develop a high-resolution colour p-OLED micro-display based on the PHOTOLEDD technology.
Funding SchemeCSC - Cost-sharing contracts
75752 Paris Cedex 15
3151 XN Hoek Van Holland
KY11 5PF Dalgety Bay
HU6 7RX Hull