Full Spectrum VTC Series (CRI 98)

WHY YUJILEDS® VTC SERIES LEDS? 

The sun is well recognized as the perfect light source because of its completely uniform, continues and broad spectrum. With the development of artificial lighting technologies, efficiency is improved significantly however the illumination quality gets worse. There is no longer a light source that is like incandescent or halogen with perfect spectrum, especially when LED is invented and widely applied, while achieving unprecedented energy saving benefits, we have sacrificed the illumination quality tremendously until the Yujileds VTC series LEDs come out.

95% spectral similarity to sunlight

The wavelength range for human visual sensitivity is generally considered as 400nm – 700nm, for which the sun spectrum covers completely. On account of the illumination principle, a standard LED only covers 430nm – 670nm with at least 20% relative radiant power compared to the 450nm peak wavelength, therefore the purple and deep red light are missed in a standard LED, furthermore the sharp peak of the blue light has been an intractable challenge for many years.

Yujileds VTC technology succeeds in broadening the spectrum coverage to 400nm – 730nm, which is 40% more coverage than a standard LED spectrum, in addition, the VTC technology eliminates the sharp blue peaks then achieves the uniform spectral power distribution hence it mimics 95% similarity to the sunlight within the visible spectrum.

No compromise on spectral quality

Not limited to a fixed full spectrum, the VTC technology offers at least six spectral patterns of 2700K, 3200K, 4000K, 5000K, 5600K and 6500K as standards and can extend to even wider CCT scopes. The spectral recipe of each CCT is well designed with Yujileds state-of-the-art LED phosphor and the well-chosen LED dies. By covering the practical solar spectra at any time all day, the illumination quality will never be compromised regardless of any CCT is selected. Eventually, we can obtain a better light source than incandescent and halogen based on LED with the full flexibility of different white lights thanks to the VTC technology.

98 CRI for true color vividness

CRI (Color Rendering Index) is a most accepted colorimetric for evaluating the ability of a light source rendering the original color of an object. Benefiting from the full spectrum, the VTC series LED performs remarkable color rendition by achieving the CRI up to 98 (with minimum 95) where the full-score is 100. Comparatively, a standard 80 CRI LED which is still widely used performs less color fidelity and saturation.

Introduce TM-30 metric for 99 color evaluation samples

The TM-30 metric is defined and proposed by the Illuminating Engineering Society (IES), aiming to provide comprehensive evaluation on color quality of new light sources especially for LED and it is released as the supplement or even replacement of CRI in the future. TM-30 utilizes 99 color evaluation samples which are selected from more than 100000 measured objects to be representative of the world of possible colors. Compared to CRI, the TM-30 is more critical on the spectral quality therefore when a standard LED has a CRI as 97, the Rf (Fidelity Index) of TM-30 is about 90, but for VTC series 99 CRI LED, the Rf is maintained as 95-97 which means the VTC technology provides extremely stable ability for rendering most of the possible colors.

Constant color rendition

Colors are not only well rendered under one specific spectrum but for all CCTs covering from the warm white to daylight. As the result of the well-designed spectral recipes, CRI values are ensured to be constant and since the VTC technology focuses on the spectral quality, likewise the TM-30 scores are maintained at high values constantly.

Optimized color consistency of SimpleBinning technology

The importance of LED color consistency is as crucial as the color rendition, for the new generation of VTC series LED, the SimpleBinning technology is introduced. A standard LED usually comes with more than ten different chromaticity bins for each CCT which is always complex and confusing to customers. With the SimpleBinning technology from Yujileds, there will be no more than two bins for each CCT and the individual bin equal to or less than 3-step SDCM, that is to say, not only the selection of chromaticity bins is greatly simplified, but the consistency of each bin is ensured. Particularly, the performance of consistency will be even more superb when applied on a Yujileds PCB with our chromaticity management.

Illuminate in a specialized way

The VTC technology is based on a unique illuminating principle than the standard LED by applying a typical 405nm LED die (violet) that excites blue, green and red phosphors, despite only changing the die and adding one phosphor seemingly, the illumination theory makes the technical procedure different. In Yujileds VTC technology, the triple phosphors are completely tailor-made for matching with the violet die for the full-spectrum performance, which makes the spectral recipes extremely complex. Nevertheless, we still have achieved stable color rendition and SimpleBinning, the VTC technology represents the most advanced LED technology at present.

MEASUREMENTS FROM EXPERTS

Delta optical thin film

Delta optical thin film focuses on complex optical filter technology for more than 50 years and it is one of the first companies to produce ultra-hard-coated optical filters. Today, the design and manufacture of high-performance fluorescence filters are the main business, and with the in-house design and production tools, Delta continues to meet the needs of the discerning OEM customers.

During the evaluation of Yujileds VTC series LED, Delta Linear Variable Bandpass Filters (LVVISBP) is applied for the measurement. The measurement procedure is as simple as putting the filters in front of the light sources, but the phenomenon is noticeable by naked eyes directly, especially when comparing to a fluorescent lamp and standard LED. The spectrum theory sometimes is difficult to understand but this measurement perfectly explains the relationship between spectral and visual differences. Every detail in the spectrum could be presented in the result after the filters, and eventually the importancy and value of a full-spectrum LED should be widely accepted.

Indie Cinema Academy

Indie Cinema Academy is a professional organization focusing on providing the education of film school level concepts and techniques to bring the audience's video projects up to the level of the masters. Indie Cinema Academy makes the skills accessible and explains every step of the way the hows and whys of the camera and lighting choices.

Lighting plays the decisive role in film shooting and Indie Cinema Academy has done a great job of collecting all LED databases from the market to compare the color rendition quality and rank the different brands or products. CRI and TM-30 are both evaluated considering the rationality and impartiality to the professional level. Yujileds VTC series LED gets the runner-up with CRI Ra 98.4, CRI Re 97.5, TLCI 99.5, CQS 97, Rf 97 and Rg 100, only defeated by the sun.