White LEDs offers uniformity benefits for low-profile packages

Technology News |
By eeNews Europe

The EV-W chips incorporate SemiLEDs’ proprietary ReadyWhite phosphor technology to deliver a uniform phosphor coating across the emitter surface that claims to greatly increase color precision and uniformity.

The availability of high-output, high-consistency unpackaged white chips offers LED packaging and luminaire manufacturers a wide variety of new COB and package options by eliminating the phosphor application from the packaging process. Innovative package-level implementations can include variable-CCT single-package solutions, and greatly simplified RGBW, WWRA, WWWR or WWGR solutions to provide enhanced CRI and higher efficiency red/amber/green augmentation.

EV-W LEDs, based upon SemiLEDs proven EV product line, are available in high-power 40-, 45-, and 53-mil low-profile vertical chips and can deliver up to 140 lumens with efficacies of 130 lm/watt at 350 milliamps, depending upon the chip bin and chosen packaging approach. Standard CCT/CRI options range from 6500K/70CRI to 2700K/80CRI, and include distributions as tight as 1/4 of a standard ANSI bin. Additional customization, including specialized phosphor options, is also available.

"A traditional barrier to the availability of creative new LED packages, especially lower-profile implementations, has been the issue of phosphor application within the packaging process," explained Mark Tuttle, General Manager for SemiLEDs Optoelectronics Co., Ltd. "The additional capital requirements, expertise, processing time, overspray and wastage issues have all either limited packaging options or unnecessarily driven up costs. By combining our rugged vertical-metal EV-blue chips, and the proprietary ReadyWhite phosphor coating technology, SemiLEDs’ EV-W eliminates blue-leakage while delivering an impressive level of color uniformity and tight binning options for low-profile and multi-color white packaged LEDs."

Historically, manufacturers who assemble LED chips into low profile packages have been faced with a substantial challenge when it comes to uniformity and cost issues. While the industry has developed effective techniques to evenly cover the blue chip in a cavity-based package, current dispensing and spray-coating techniques tend to deliver a domed distribution rather than a flat, uniform coating. While moving to a vertical-metal chip solves the problem of blue leakage that would typically emanate from the sapphire substrate with a dispense-coated or spray-coated horizontal chip, SemiLEDs ReadyWhite technology additionally addresses the important issue of uniformity.

The SemiLEDs’ EV-W chip series is designed for manufacturability and rugged longevity and is available with an option of gold/tin (AuSn) metallization to support eutectic bonding to further enhance thermal characteristics. The SemiLEDs EV-W series is RoHS compliant with production quantities available now.

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