The 'artificial sun' is not a true replica of the sun, but a simulation of the core characteristics of sunlight through technological means, providing a controllable and standardized lighting environment for scientific research and industrial testing. The core principles, light source selection, and optical design together form the technological foundation of this precision system.
Basic principle: Simulating the core characteristics of solar radiation
The core goal of a solar simulator is to reproduce the spectral distribution, irradiance intensity, and spatial uniformity of solar radiation. The spectrum of sunlight on the Earth's surface covers 280nm to 2500nm, including ultraviolet, visible, and infrared bands. Its radiation intensity is affected by atmospheric mass (AM), with a typical total radiation of 1kW/m ² on a clear day (AM1.5). The simulator adjusts the light emitted by the light source to a spectrum that meets the AM1.5 standard through an optical system, and forms uniform irradiation on the test surface, thereby simulating the actual effect of sunlight on materials and devices.
Light source selection: Collaborative application of xenon lamp and LED
The light source is the "heart" of the simulator, which needs to meet the requirements of spectral continuity, stability, and dynamic control. Xenon lamps generate a continuous spectrum similar to that of the sun through high-voltage arc discharge, particularly adept at covering visible and near-infrared wavelengths, but with insufficient intensity in ultraviolet and infrared; LEDs fill the gap through multi band combinations (such as UV-A365nm, infrared 850nm) and support dynamic dimming (such as simulating spectral changes at sunrise and sunset). For example, the Guangyan Technology SS-PST100R simulator uses a xenon lamp+12 channel LED hybrid light source to achieve full band coverage from 250nm to 2500nm, with spectral matching accuracy (deviation<5%).
Optical design: precise control of uniformity and collimation
The optical system achieves high-precision simulation through three steps of "focusing uniform light collimation". Taking the spotlight solar simulator as an example: the light emitted by the xenon lamp light source is converged to the second focal point through an ellipsoidal reflector, the lens array divides the light field and eliminates "hotspots", and the collimator converts the light into parallel beams, ultimately forming uniform irradiation on the test surface. For example, the Luminbox full spectrum LED simulator from Zichuang Measurement and Control achieves an non-uniformity of only 1.8% in the 45cm × 45cm area through an optical integrator, with a fluctuation of ≤ 0.5% within 20 minutes, meeting the stringent requirements of photovoltaic cell testing, material aging experiments, and more.
From the laboratory to the industrial line, solar simulators have made technological breakthroughs in "accurate spectra, uniform irradiation, and stable operation", providing a "artificial sun" for human exploration of clean energy and development of new materials.