High CRI LED Lighting

Why CRI is so important

CRI (Color Rendering Index) is a measure of how accurately a light source illuminates objects’ true colors. With the development of the LED industry, CRI is cared where the applications need dramatical improvement in the appearance of objects, particularly in retail stores, shops, supermarkets, museums, galleries, and exhibits where colors are prominent and presentation and appearance are critical.

CRI can determine the worth of merchandise, the commercial performance of a business place, and the quality level of industrial production. And with the progress of the technological progress of the Fourth Industrial Revolution (Industry 4.0), CRI is definitely getting more and more important everywhere in the lighting world.

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In our product series, the BC series is the representative product of high CRI lighting. We will introduce the innovation brought by BC technology to high CRI.

Why CRI is so important

The way of achieving high CRI LED lighting solidly? We know better

Not all white light is the same. Many of the incandescent and halogen “replacement” LED lights currently on the market use less energy but are not true replacements as the white light they emit is of relatively poor quality. In applications where appearance is of paramount importance, light quality cannot be compromised.

We focus on light quality vibrant colors true appearance by achieving the CRI up to 98. Yujileds® high CRI LED technology is based on the efficient blue die, mixing with Yuji advanced phosphors which are all developed and manufactured by ourselves, and specifically designed spectral recipes. Compared to the nominal high CRI LED lighting – we know better – starting from the level of the luminescent material. With the full industrial database, we hold every detail and follow how to achieve real high CRI solidly.

A typical high CRI LED

Wavelength matters

To stably achieve high color rendering at various color temperatures, defining the wavelengths of LED die and phosphors is necessary and crucial. Each color temperature from Yujileds® has a unique combination to make the color rendering index stable at various color temperatures. By fine-tuning the wavelength of LED die and phosphors, we avoid the decrease of CRI at different CCTs than competitors.

Wavelength Matters
SEM Phosphors

Phosphor stability matters

The stability of the phosphor is a crucial factor determining the reliability of an LED. Lighting quality is not only about the lumen maintenance, but is about the chromaticity and CRI maintenance. The Yuji LuAG and nitride phosphors are super stable, making the color and the color rendition the same as new even after years of use.

Spectrum pattern matters

The spectrum pattern, which is formally called the Spectral Power Distribution (SPD), is usually ignored until the metamerism happens, but SPD is the gene of a light and the color metrics including CRI are all determined by it. We focus on the research and development of SPD than only on the metric numbers. Many details are behind CRI like the individual Ri, but these details together are affecting the color quality of the light that should not be overlooked.

Spectrum matters
Raw material matters

Raw material matters

Beside the LED die and phosphor which are the most key materials, others constituting the LED package are non-negligible, even the designs of these materials are also the crucial factors affecting the reliability, long time working stability and lumen/chromaticity maintenance. We deeply understand high CRI lighting is not just a good CRI score, but is the absolutely excellent lighting quality thus we always take care of the raw materials even if it generates higher cost.

Enhanced CRI R9 technology

The standard CRI Ra is the average score of the first eight Test Color Samples (TCS), where the 9th for saturated red color is missed. However, R9 is significantly different for different light sources. If the light source does not have sufficient spectral power distribution in 600nm-800nm, it will be difficult to get a high R9. The capability of rendering the red color cannot be promised if the red spectrum is missed or not sufficient in the original light. Comparing a standard LED to Yujileds® high CRI LED at 3000K, although the emission principle is the same, the results present different R9 significantly where the standard LED is R9 = 13 and our LED is R9 = 96.

compare with different R9

Cover wide CCT range

When most of the manufacturers’ high CRI LEDs are limited to the range of 2700K-5000K, where lower and higher CCTs are missed when applying to more specific applications, we are able to extend high CRI performance from 1800K to 20000K thanks to our unique phosphor solutions, maintaining the CRI still above 92-97 and with excellent spectra qualities. Moreover, looking into the specific Ri in each CCT, the color rendition performs uniformly without significant differences, even for the extreme CCTs.

high CRI 1800K to 20000K
Ri from1800K to 20000K

Beyond high CRI is “all” high CRI

In practical applications, LED can work individually or as a group on a printed circuit board, therefore the consistent CRI is critical for both. Generally, a manufacturer only provides a typical datasheet or report to infer the overall performance but the risk is that if some LEDs in a batch have worse CRI but the typical report cannot match, especially when the application uses fewer LEDs which means CRI is difficult to be balanced with those higher ones, then the risk falls to the customers’ lighting fixture.

Understanding the statistical features of LED and processing relevant analysis and control is important and this is what we are doing. We provide the full statistic and data support from the production of 1,000,000pcs of each CCT from 1800K to 20000K and present all characteristics and guidance for customers to make reliable simulations and predictions accordingly. And from the statistical data, we can also read that the Yujileds® high CRI LED perform excellently on the CRI consistency, furthermore, with SimpleBinning solution, the overall consistency can be improved even more on the CRI aspect.

CRI statistics

No compromise to the luminous efficacy

It is always in a dilemma when determining high CRI or better lm/W, both are important, and neither should be compromised for high-quality LED lighting. Yujileds® optimizes the technical solution to keep a balance between efficacy and high CRI spectra and develops different solutions for even higher efficacy.

High efficancy and high CRI

Product selection for high CRI