Philips was founded by Frederik Philips and his son Gerard Philips in 1891 in Eindhoven in Holland. They concentrated on the mass production of incandescent lamps. By the end of the 1890s, Philips & Co. is one of the largest producers in the Netherlands and, with 1,000 employees, the country's largest industrial employer. In 1928 Philips bought Mullard after a joint venture in vacuum tubes. Philips had been one of the main originators with in the musical field. They invented some of the great valve designs such as the EL34 and EL84.