Patent attributes
An illuminating device for plant cultivation to cultivate plants has a base, a light source, a light converging plate, a position-adjusting device and a distance sensor. A height of the plants is detected by the distance sensor, and then a distance between the light source and the light converging plate is adjusted according to the height detected, and as a result, an illumination field of the light source is altered by the light converging plate. Therefore, an illumination field of the light passing through the converging plate is narrower to illuminate the plants located farther away and prevents waste of light energy. When the plants grow higher, the distance between the light source and the light converging plate is adjusted to provide a wider illumination field to ensure that light can be distributed evenly among the plants. Utilization efficiency of light energy is therefore improved.