BC LED SMDs

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. In spectral analysis and CRI arithmetic, the integral area between the spectrum and the spectral reflectance response of TCS-9 decides the R9 to a large extent – in other words, how much of TCS-9 spectra reflectance is overlaid in the light source spectrum, that is a key factor.

It is obvious to see from 600nm, which is just the start of red color in the visible spectrum, the TCS-9 spectral reflectance raises sharply, in consequence, 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. In the comparison of fluorescent and halogen, apparently, halogen offers the richest 600+nm power, while the discrete fluorescent spectrum has limited energy there. Then in this comparison, halogen R9 = 99 but the fluorescent is R9 = -27. Comparing a standard LED to Yujileds® BC series LED at 3000K, although the emission principle is the same, the results present different R9 significantly where the standard LED is R9 = 13 and Yujileds® BC series LED is R9 = 96.

High CRI becomes the tendency for LED products in recent years, and manufacturers start providing “nominal” high CRI LED to the market, however, as the result of a detailed investigation, most manufacturers’ high CRI LED are limited in the range of 2700K-5000K, where lower and higher CCTs are missed when applying to more specific applications. Yujileds® BC series LED extends high CRI performance from 1800K to 20000K CCT.

In comparison to a standard LED on the market is generally in the available CCT range of 2700K-6500K, and high CRI LEDs are more limited to fewer options, Yujileds® BC series LED can be extended to 1800K-20000K with the unique phosphor solutions, maintaining the CRI still above 92-97 and excellent spectral qualities. Moreover, looking into the specific Ri in each CCT, the color rendition is well balanced without significant difference, even for the extreme CCTs. Therefore, the CRI is always consistent regardless of what CCT we combine with the Yujileds® BC series LEDs.

In actual 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 averaged 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 are important in this case, and these are what we do for our BC series LED. 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 simulation and prediction accordingly. And from the statistical data, we can also read that the BC series LED perform excellently on the CRI consistency.