Photometric Testing, Laboratory Teardowns, and Accelerated Lifetime Testing of OLED Luminaires (CALiPER Report 24, Supplemented)

Stress Testing of Organic Light- Emitting Diode Panels and Luminaires

“…For example, an entire OLED panel may not fail at once; instead, pixels may fail within the OLED panel, reducing luminous flux and becoming visible to the end user. In addition, the multiple emitters used to produce white light in OLEDs may exhibit significantly different lifetime characteristics, which can cause chromaticity shifts through different mechanisms and at different rates than inorganic LED devices do [4]. Other failure modes that can occur in OLED lighting systems include panel shorting, moisture ingress, and driver failure [4].…”

“…The U.S. Department of Energy (DOE) has supported the development of OLED technologies as an integral part of the solid-state lighting (SSL) program. Recently, DOE published four reports highlighting OLED technologies including two field evaluations [2,3], a Commercially Available LED Product Evaluation and Reporting (CALiPER) study as part of a laboratory evaluation [4], and a market analysis [5]. A general conclusion from these studies is that the cosine emission profile of the light produced by OLED devices is beneficial, especially for indoor lighting, and provides the product with a unique look and functionality.…”

“…While panels from both manufacturers use fluorescent blue emitters and phosphorescent red and green emitters, LG panels employ a 3-tandem stack device structure [6], whereas panels from OLEDWorks incorporate a 6-tandem stack structure [7]. Panels from LG Display have been used in a broad range of luminaire types examined in DOE studies including both Gateway and CALiPER reports [2][3][4][5]. The luminaires in these DOE reports that incorporated panels from OLEDWorks mainly used the older Brite 1 technology [2 -4], although the newer Brite 2 panel was examined in the most recent DOE report [3].…”

“…Previous DOE reports provide a snapshot of the manufacturer's specified performance for these OLED panels, and relevant parameters are collected from these previous reports and provided in Table 1-1. Spectral power distributions (SPDs) and Illuminating Engineering Society (IES) Technical Memorandum-30 (TM-30) calculations for these panels were included in previous DOE studies using data from CALiPER studies and the manufacturers [2][3][4][5]. Initial reliability studies were performed by RTI International on the Chalina luminaire from Acuity Brands, and these results were included in the CALiPER 24 report [4].…”

“…While this method works well with LEDs, it often causes increased flicker with OLEDs [2]. Previous DOE reports have also indicated the importance of maintaining sufficient headroom in the driver voltage to accommodate the expected increase in panel impedance during use [4]. An additional finding of previous DOE studies has been a wide range in driver efficiency, often caused by the dearth of commercial OLED driver products and the tendency for most OLED luminaires use an LED driver that may not have the optimal voltage and power efficiencies for use in the OLED device [4].…”