Two LED downlight systems are assembled as shown in the table below. For the ChromaLit™
system, an array of blue LEDs emitting at 455nm wavelength is mounted on a printed circuit board
(PCB) which is mounted to a heat sink. Also attached to the PCB are a diffuse reflective sheet
(White97™ film from WhiteOptics) that closely surrounds the LED elements and a tapered walled
mixing chamber, also coated with reflective film. The reflective sheet used in this system has diffuse
reflectivity of 97%.
Performance Comparison of Two LED Downlight Designs ChromaLit™ Remote Phosphor Lighting System vs. Conventional White LED System
Conventionally, LED downlights implement white LEDs that are constructed of a blue LED device
coated with phosphor. In the application, these LEDs are arranged in combination with a diffuser
optic in order to perform with uniform luminance. This architecture is compared with a downlight
designed with a ChromaLit™ remote phosphor light source converting the light emitted by an
array of blue LEDs in a reflective mixing chamber. The blue LEDs in each system are controlled to be
equivalent and both systems are designed to produce light of 3000K correlated color temperature
(CCT) and 80CRI. The light output and luminous efficacy of both systems is compared under room
temperature conditions with elevated system temperature during steady state operation.