An array of LEDs are grown by epitaxy on row-connecting conductor strips extending in parallel spaced relationship to one another on the surface of a semiconductor substrate and are thereby electrically interconnected in rows. The row-connecting conductor strips are formed by ion implantation of a p-type dopant into parts of an n-type silicon substrate. Column-connecting conductor strips extend over the light-emitting surfaces of the LEDs for electrically interconnecting them in columns. The LEDs are lit up individually by voltage application between one of the row-connecting conductor strips and one of the column-connecting conductor strips.