Question 1

What is SPD in color?

Accepted Answer

The spectral power distribution (SPD) describes the power (or intensity) emitted by a light source at each wavelength within the visible spectrum. Simply put, it acts as the light source’s “rainbow” and “fingerprint”—revealing not only which colors of light (wavelengths) the source emits but also the relative intensity of each color. Through the SPD, we can gain a precise understanding of a light source’s “light composition,” rather than just its apparent color. The SPD serves as the “master template” for all optical performance characteristics. All lighting metrics of interest—including color temperature (CCT), color rendering index (CRI), chromaticity coordinates (x, y), and blue light hazard classification—can be calculated or derived from it.

Question 2

What's full-spectrum light?

Accepted Answer

Full-spectrum light refers to light that covers the electromagnetic spectrum ranging from infrared to near-ultraviolet, or light that includes all visible light wavelengths beneficial to the life activities of plants and animals; sunlight is a typical example. Although the spectral distribution of sunlight reaching the Earth’s surface varies with time of day, latitude, and atmospheric conditions, sunlight is still recognized as a full-spectrum light source. Neither the Chinese national lighting standards nor the IES/LM79 optical standards provide a mandatory, unified quantitative definition of “full-spectrum.” Currently, many indoor lighting fixtures—such as ceiling lights, desk lamps, and chandeliers—claim to be full-spectrum fixtures, but this merely means that the fixtures are designed to mimic natural light. ZGSM believes that priority should still be given to SPD and color rendering indices. If you want less blue light, focus on the proportion of blue light in the SPD curve. If you are concerned about color rendering, pay attention to the CRI value in the LM79 report.

Question 3

Which is brightest, 3000K, 4000K or 5700K?

Accepted Answer

Strictly speaking, there is no direct correlation between color temperature and brightness in LED lighting. We know that brightness is typically measured in lumens (lumen), while Kelvin (K) is the unit of measurement for color temperature. However, when the color temperature is too low, luminous efficacy (Luminous efficacy and the strategies to improve it) decreases significantly—for example, in LED chips rated at 1800K and 2200K, as well as in low-blue-light LED chips. There are two main reasons for this. First, these LED chips often use long-wavelength red-orange phosphors, which increase photoconversion losses. Second, the human eye has varying sensitivity to different wavelengths of light—that is, the human eye’s visual response function differs. For example, to the human eye, 5700K light appears brighter and more glaring because it is whiter and has higher sensitivity; in contrast, 2200K light (which has an amber hue) has a V(λ) ≈ 0.6, which is much lower than the V(λ) = 1 for yellow-green light.

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LED Street Light

High Mast Light

Led Flood Light

Solar Flood Light

LED High Bay Light

LED Tunnel Light

LED Garden Light

Led Bollard Light

Solar Street Light

LED Traffic Light

LED Canopy Light

Lighting Accessories

Smart Systems

Simulation Design

Smart Financing