High-Color-Quality Multipackage Phosphor-Converted LEDs for Yellow Photolithography Room Lamp

This paper introduces a multi-package light-emitting diode (LED) system with the ability to realize an efficient and good color quality yellow room lamp under a photolithography environment. Various yellow room LEDs were fabricated by combining two, three, and four packages among green (G), yellow (Y), amber (A), and red (R) phosphor-converted LEDs (pc-LEDs) capped with long-wavelength pass dichroic filters (LPDF). The values of luminous efficacy (LE), color rendering index (CRI), and color quality scale (CQS) of the nine combinations of multi-package pc-LEDs are compared and optimized for application to a yellow room lamp. The optical properties of the selected G-A-R multi-package LED are compared with those of fluorescent light tubes (FT) and a yellow fluorescent light tube (YFT), which are generally used in photolithography rooms. The proposed G-A-R multi-package LED provides high luminous efficacy of 100 lm/W and good color quality (CRI of 78 and CQS of 36) at correlated color temperature (CCT) and color coordinates similar to those of currently commercialized YFTs.