Needless to say, an LED (light-emitting diode) is a semiconductor light source and LEDs are used as indicators and display elements in various devices. During the past few decades, the light intensities of LEDs have increased a great deal; therefore, white LEDs in particular are increasingly used for lighting.
For more than thirty years, the author has been doing research on applications of LEDs other than such conventional utilizations. His applications are novel and original. Furthermore, they are extensively applied in the fields of engineering, science, horticulture, agriculture, medicine, fishery and various LED commodities. In this paper the author will introduce his pioneering research on his LED applications.