PhosphorTech was invited to present on New Applications of Ceramic Phosphor Materials in LEDs and Lasers.
Conference Abstract
Nearly all current white solid-state lighting (SSL) systems used for general illumination are based on the phosphor converted LED (pcLED) architecture, which offers a practical and mass producible structure for white light generation. Various ceramic phosphors are also being used to convert high energy ultraviolet/visible (UV/Vis) light to a wide range of wavelengths, including infrared. Laser-based SSL devices also exist and the application of laser-excited phosphor technology is now prevalent in automobile headlights, image projection devices, even long-range flashlights. This study will present recent work on new phosphors used to convert narrow-band SSL emitters into both broadband and narrowband optical energy that cannot be achieved by LEDs alone. For example, UVA/UVB phosphors can be combined with UVC LEDs to produce full spectral coverage in the ultraviolet part of the spectrum. Similarly, near-infrared (NIR) and short-wave infrared (SWIR) phosphors can be combined with visible LEDs or lasers to produce a broadband emission throughout the infrared that can be used for a wide range of spectroscopy and imaging applications. Lasers can also be used in the development, analysis, and optimization of phosphors. Using lasers as excitation sources instead of conventional LEDs, it is possible to perform more accurate and high-power density lifetime and color measurements on the optical converters by de-coupling the behavior of the phosphors from the source and encapsulants used in high power SSL devices. Unlike an LED light, a laser beam can be easily focused into a 200-300 mm spot from a distance away from the sample under test, which helps in directly monitoring the optical output and operating temperature of the down-converter independently of the excitation source itself. Using such an approach, several different types of LED phosphor materials can be monitored and compared simultaneously for thousands of hours.