4 March 2013 Near-field photometry for organic light-emitting diodes
Author Affiliations +
Organic Light Emitting Diode (OLED) technology is rapidly maturing to be ready for next generation of light source for general lighting. The current standard test methods for solid state lighting have evolved for semiconductor sources, with point-like emission characteristics. However, OLED devices are extended surface emitters, where spatial uniformity and angular variation of brightness and colour are important. This necessitates advanced test methods to obtain meaningful data for fundamental understanding, lighting product development and deployment. In this work, a near field imaging goniophotometer was used to characterize lighting-class white OLED devices, where luminance and colour information of the pixels on the light sources were measured at a near field distance for various angles. Analysis was performed to obtain angle dependent luminous intensity, CIE chromaticity coordinates and correlated colour temperature (CCT) in the far field. Furthermore, a complete ray set with chromaticity information was generated, so that illuminance at any distance and angle from the light source can be determined. The generated ray set is needed for optical modeling and design of OLED luminaires. Our results show that luminance non-uniformity could potentially affect the luminaire aesthetics and CCT can vary with angle by more than 2000K. This leads to the same source being perceived as warm or cool depending on the viewing angle. As OLEDs are becoming commercially available, this could be a major challenge for lighting designers. Near field measurement can provide detailed specifications and quantitative comparison between OLED products for performance improvement.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Rui Li, Rui Li, Krishnan Harikumar, Krishnan Harikumar, Alexandar Isphording, Alexandar Isphording, Venkat Venkataramanan, Venkat Venkataramanan, } "Near-field photometry for organic light-emitting diodes", Proc. SPIE 8641, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XVII, 86410A (4 March 2013); doi: 10.1117/12.2002110; https://doi.org/10.1117/12.2002110


Evaluation of OLED and edge-lit LED lighting panels
Proceedings of SPIE (September 06 2016)
Visible LEDs the trend toward high power emitters and...
Proceedings of SPIE (November 25 2002)
Optical metrology for LEDs and solid state lighting
Proceedings of SPIE (February 09 2006)
Concepts for future solid state lighting solutions
Proceedings of SPIE (August 18 2010)

Back to Top