CQS and CRI

SSL (Solid State Lighting) product’s color quality is very important; people pay more and more attention to it. CRI already has 40 years history. CIR is a quantitative measure of the ability of a light source to reveal the colors of various objects faithfully in comparison with an ideal or natural light source, which is color fidelity degree.

There are many problems when CRI is applied in LED at present. In NIST, they develop CQS (Color Quality Scale) system, which successfully solves the problem when CRI is applied in SSL light source. However, for traditional light sources, the results are consistent with the values of CRI.

Color fidelity is not the only indicator to measure the quality of white light. Light color quality also includes some other areas; in particular, when increase object color saturation, visual satisfaction and color distinguish ability will also increase. CQS basically is a guarantee system; the results obtained are similar with Ra. However, CQS has many improvements; it specifically takes the capability of object color displacement direction into account. Therefore, CQS value can well match the visual evaluation of color enhanced illumination, while CQS can also give exact fidelity value for non-color enhanced illumination. For all light sources, CQS values are able to indicate the full light color quality of the products.

In addition, we need to pay attention that high CRI value does not guarantee good quality light color. At present, most lighting industry at home and abroad are still using CRI conception. In next period of time, we are still using CRI conception to assess color fidelity degree.

Lisun Electronics (Shanghai) Co., Ltd is lead in lighting test equipment, EMI/EMC test system and safety test instrument. Its quality system has been strictly certificated by ISO9001:2008. The Lisun Group products have been authenticated by the third party lab and were by CE certificate. As a CIE supportive membership, all of the test instruments produced by Lisun Group were designed according to CIE standards.