A violet LED combined with red, green, and blue phosphors yields a lamp that Verbatim says will render fine details and color nuances in objects better than other white-LED approaches.
Verbatim has introduced the VxRGB Vivid Vision MR16 LED retrofit lamp in Europe, and perhaps more importantly, a new approach to generating white light with LEDs. The solid-state lighting (SSL) product is based on a violet LED and a combination of red, green, and blue (RGB) phosphors that makes the lamp especially suited for applications such as museums and high-end retail where accurate rendition of small differences in color hues and textures is important.
The VxRGB technology will likely be used in a variety of products going forward, and the LEDs could ultimately be sold by Verbatim's parent Mitsubishi Chemical Corp, who developed the phosphors and is fabricating the LEDs, or even licensed to another LED maker. The initial 6.5W MR16 product delivers 180 lm over a 35° beam pattern with a color temperature of 2900K and a CRI of 85. Verbatim says that the lamp can replace 20W halogen lamps.
The company said that the technology is "particularly effective in spaces where small differences in color hues, tints and textures can have a significant impact." The violet light that escapes the LED, and the RGB light emitted by the phosphors combine to deliver even energy across the entire human visual spectrum – much like sunlight. The company says that the technology can be used to produce CCTs ranging from 2500K to 6000K.
The claimed advantages, however, are difficult to quantify. The company has said the VxRGB technology can enable 90 CRI SSL products although this initial product is 85 CRI. "The CRI is not the measurement that is relevant for this type of specialist product," said Jeanine Chrobak-Kando, business development manager at Verbatim. "It is all down to customer needs in utilizing the unique characteristics of the light in making objects appear more vivid with high perception fidelity."
Indeed, the VxRGB lamp may be an example of just has poor CRI is in terms of a measure of color metric for SSL products. As we covered in our color-science series of articles, CRI can penalize lamps that over saturate colors even though that may be visibly desirable in some applications.
Alas, the initial incarnation of the VxRGB technology offers far lower efficacy than other LED MR16 lamps. The lamp efficacy is below 30 lm/W and that doesn't include the efficiency lost in the power transformer that drives the low-voltage lamps. While the lamps still use less power than legacy sources, they are far from the best LED lamps in terms of energy savings. For example, Soraa announced new MR16s at Lightfair that can replace 65-75W halogens and deliver 80-85% energy savings.
In general, LED-based designs that attempt to deliver warm color temperature and high CRI struggle to also deliver maximum energy savings. For example, typical warm-white LEDs based on blue emitters must include red phosphor in the formulation and that generates wasted energy outside the human sensitivity range. In the case of Verbatim, it's not immediately clear where or how the inefficiency comes into play.
Still, if the lamps perform as Verbatim claims, the relatively moderate energy savings may be acceptable in specialty applications. Chrobak-Kando said, "We plan to expand our product portfolio based on VxRGB technology in the future. This technology offers us greater freedom in creating products with a dedicated light output that fits according to special applications and customer needs."
