In these days, the basic performances of white OLEDs are dramatically improved and application of OLEDs to
"Lighting" is expected to be true in the near future. We have developed various technologies for OLED lighting with the
aid of the Japanese governmental project, "High-efficiency lighting based on the organic light-emitting mechanism." In
this project, a white OLED with high efficiency (37 lm/W) and high quality emission characteristics (CRI of 95 with a
small variation of chromaticity in different directions and chromaticity just on the black-body radiation curve) applicable
to "Lighting" was realized by a two-unit structure with a fluorescent deep blue emissive unit and a phosphorescent green
and red emissive unit. Half-decay lifetime of this white OLED at 1,000 cd/m2 was over 40,000 h. A heat radiative, thin
encapsulation structure (less than 1 mm) realized a very stable emission at high luminance of over 3,000 cd/m2. A new
deposition source with a hot-wall and a rate controllable valve was developed. Thickness uniformity within +/- 3% at
high deposition rate of over 8 nm/s, high material utilization of over 70 %, and repeatable deposition rate controllability
were confirmed.
Organic light emitting diodes (OLED) are expected to be used in next generation solid state lighting sources serving as
an alternative to conventional incandescent bulbs and fluorescent lamps. OLEDs will provide the environmental
benefits of possible considerable energy savings and elimination of mercury, as well as some other advantages such as
thin flat shape, planar emission, and no UV emission. Recently, important properties of OLEDs such as efficiency and
lifetime have been greatly improved. Additionally, for lighting applications, a high color rendering index (CRI) at the
desired CIE chromaticity coordinates, high luminance and large area uniform emission, and high stability over long time
operation are also required. In this paper, we describe the development and performance of our high CRI OLEDs: the
conventional OLED with multiple emissive layers and the multi-unit OLED with only two emissive units (a fluorescent
blue emissive unit and a phosphorescent green / red emissive unit). Related technologies for OLED lighting to obtain
uniform emission at high luminance in large areas are also described.
Organic Light Emitting Diode (OLED) is an emerging technology as one of the strong candidates for next generation
solid state lighting with various advantages such as thin flat shape, no UV emission and environmental benefits. At
this moment, OLED still has a lot of issues to be solved before widely used as lighting devices. Nonetheless, typical
properties of OLED, such as efficiency and lifetime, have been recently made great progress. For example, a green
phosphorescent OLED with over 100 lm/W and a red fluorescent OLED with an estimated half decay time of over
100,000 h at 1,000 cd/m2 were reported. Large area, white OLEDs with long lifetime were also demonstrated. In this
way, some of the issues are going to be steadily overcome. In this publication, we will present a phosphorescent white
OLED with a high luminous efficiency of 46 lm/W and an external quantum efficiency of 20.6 percent observed at 100
cd/m2. This device achieves a luminous efficiency of 62.8 lm/W with a light-outcoupling film attached on the glass
substrate. This is one of the highest values so far reported for white OLEDs. And we will also show a color-tunable
stacked OLED with improved emission characteristics. This device minimizes a viewing angle dependence of the
emission spectra and has color tunability from white to reddish-white. These technologies will be applied to OLED
lighting.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.