用于温室植物补光的LED组合光源的设计与优化

Design and optimization of LED assembled light source used for plant light supplement in greenhouse

选择合适的红、蓝光LED组合,能够形成与植物光合作用和形态建成的光谱吸收峰值基本吻合的光源,而保证光源在照射面内辐照度均匀分布是非常重要的。文章采用点光源模型,设计了两种红、蓝光LED组合阵列:阵列1,红、蓝光LED个数比为1∶1,LED间隔均匀排列;阵列2,红、蓝光LED个数比为4∶1,4个红光LED分别位于正四边形的顶点,蓝光LED位于4个红光LED的中心位置。通过数值计算和光学软件Trace Pro仿真表明:阵列2在辐照度分布均匀性上优于阵列1。在阵列二的基础上进行如下优化和改进:增大阵列组合的LED间距。改进后的LED提高了照射面内R/B比的均匀化程度;由于其阵列相邻LED间距较大,有利于电路板的焊接和LED阵列整体散热。通过工作电流的改变来控制光源光强和得到植物补光所需的R/B比。模块化的设计可以实现快速安装、更换和拓展的目的,并保持照射区域内辐照度分布均匀。

The combination of appropriate chosen red and blue LED could be a kind of light source which is similar as the absorption peak of light spectrum of plant photosynthesis and morphogenesis. It is significant to make sure the uniform distribution of irradiation of the light source. Two combinations of array were designed through the point light source model. Array 1： The proportion of red LED and blue LED was 1∶ 1,the array was evenly spaced. Array 2：the proportion of red LED and blue LED was 4∶ 1,every four red LED took the four corners of the square,and one blue LED took the center. The calculation and simulation of the Trace Pro software showed that： the uniformity of array 2 was better than array 1. The array 2 was progressed as follow： increase the distance of the LED array. With this progress,the uniformity of the proportion of R / B in its radiate area increased,which was beneficial for the weld of circuit board and overall heat dissipation of LED array. In order to meet the needs of supplementary lighting of plants,intensity of light was controlled through changing the working current. Modularized design could make the install,exchange and expandability rapid,and keep the uniformity of the light in the radiated area.