High-performance OLED microdisplays on CMOS backplanes have been developed using multi-stack white OLED architectures for higher brightness and longer lifetime – the expected benefits from stacked architectures. Unlike OLED lighting, which is bottom emission, the top-emitting OLED on the silicon backplane has a Fabry–Pérot parallel plate microcavity. The combination of the multi-stack approach and the cavity provides additional degrees of design freedom which can be used to optimize the interaction between the OLED formulation and optics of the device. This combination allows reduced power, balanced sub-pixel currents, and increased color gamut. Examples are shown of full color microdisplays made with 3, 4, and 5 stacks that are capable of 5,000 cd/m2 peak luminance with an OLED power consumption for normal video of approximately 150-175mW per square cm of active area. We also show examples of low persistence displays operating at 10% duty cycles with peak luminance of 10,000 cd/m2 and power consumption with normal video of less than 50 mW per square cm of active area. The broad toolkit demonstrated here enables the design optimization of multi-stack OLED microdisplays for many different product requirements spanning AR, VR and other near-eye applications.
This paper describes Eastman Kodak Company's commercialization efforts to develop new materials and formulations for monochrome and full-color displays. We have found a new set of materials, and combinations thereof, that improve luminance efficiency, lower drive voltage, and increase the operational stability of OLED devices. We report the developments in formulations for blue and white OLEDs based on fluorescent dopants that provide lifetimes exceeding 10,000 hours for blue, and 50,000 hours for white OLEDs at a starting luminance level of 1000 cd/m2. A red formulation, based on a fluorescent dopant using a new host, is shown to give a record luminance efficiency of 7.8 cd/A combined with excellent color and lifetime. We have found a phosphorescent red-emitting device using a novel host material that gives an excellent efficiency of 9.6 lm/W. Further progress has been made in a new electron-transport layer to reduce display drive voltage, and thus reduce power consumption, while simultaneously increasing operational stability. We have compared this performance with currently available systems.
We have developed novel formulations through a combination of new materials and a co-dopant/co-host systems approach. These novel formulations offer significant improvements in efficiency, lifetime, and color, which are suitable for fabrication of full-color OLED displays. In this report, we will review the progress made at Kodak and compare it with currently available systems.
Eastman Kodak Company and SANYO Electric Co., Ltd. recently demonstrated a 15" full-color, organic light-emitting diode display (OLED) using a high-efficiency white emitter combined with a color-filter array. Although useful for display applications, white emission from organic structures is also under consideration for
other applications, such as solid-state lighting, where high efficiency and good color rendition are important. By incorporating adjacent blue and orange emitting layers in a multi-layer structure, highly efficient, stable white emission has been attained. With suitable host and dopant combinations, a luminance yield of 20 cd/A and efficiency of 8 lm/W have been achieved at a drive voltage of less than 8 volts and luminance level of 1000 cd/m2. The estimated external efficiency of this device is 6.3% and a high level of operational stability is observed. To our knowledge, this is the highest performance reported so far for white organic electroluminescent devices. We will review white OLED technology and discuss the fabrication and operating characteristics of these