Microdisplays based on OLED-on-Silicon Process
The market for head mounted displays (HMDs) and smart glasses is expected to grow rapidely over the next five to ten years, where devices with Augmented Reality (AR) capabilities and sunlight readability start getting increasing share. Due to their superior image quality, low footprint and very low power consumption, OLED microdisplays are the preferred display component for smart glasses and HMDs. MICROOLED has been selling OLED microdisplays for head mounted displays, camera viewfinders and other applications since 2012, with a mean annual growth rate of over 40%. In order to extend our offer and satisfy the new technical requirements for AR and sunlight-readability, the technology has to be improved in order to deliver considerably higher brightness levels compared to the products available today.
The broad aim of this work is to provide a comprehensive demonstration of the outstanding performances and industrial feasibility of a new OLED-on-silicon process which will enable OLED microdisplays to address new fast growing markets in the field of augmented reality thanks to a largely increased (10X) luminance and efficiency. Three main actions are considered in the project: the development of a new device architecture including CMOS backplane, OLED device architecture, and RGB primary generation, the implementation of the related manufacturing capability for the new architecture, and finally the demonstration of the performance in a prototype of an end product.
The first action includes in particular:
- Development of a highly efficient OLED device architecture for high brightness, performed by CEA-LETI and Microoled
- Development of a new architecture for the generation of the RGB color primaries, performed jointly by CEA-LETI, Microoled, ST, and Encapsulix
- Design and realization of a CMOS backplane circuit to drive the new optical device architecture. Design is performed by CEA-LETI and Microoled and manufacturing by ST.
In the end, display modules with a brightness of 3000cd/m² for full color representation will be demonstrated, which is ten times more compared to currently available devices.
The second action concerns the integration of the new architecture into the existing OLED-on-silicon process flow. The architecture will be optimized for manufacturability using existing tools and deposition process, by achieving the required efficiency and spectral performance with an adequate choice of industrial grade materials, by achieving good overall electro-optical performances compatible with CMOS, good lifetime and finally by having a significant improvement of process control during deposition, and a deposition of a large number of layers within a reasonable TACT time.
In parallel, the potential of the new technology will be demonstrated with a product demonstrator of a typical end-product that requires high luminance OLED microdisplays. The end product is provided by Polaris Vision Systems.