Abstract: An input apparatus includes: a display plate having a plurality of display sections; an electrostatic touch panel provided at a lower face of the display plate; an operation body on which the display plate and the electrostatic touch panel are placed; a plurality of light-emitting elements for illuminating the plurality of display sections of the display plate from a lower side of the display plate through the electrostatic touch panel; and a control section that is electrically connected to the electrostatic touch panel and the plurality of light-emitting elements, and that controls light emission of the plurality of light-emitting elements in accordance with touch operation to the electrostatic touch panel.

Abstract: An optical semiconductor device is provided with a low concentration p-type silicon substrate (1); a low dopant concentration n-type epitaxial layer (second epitaxial layer) (26); a low dopant concentration p-type anode layer (27); a high concentration n-type cathode contact layer (9); a photodiode (2) made of the anode layer (27) and the cathode contact layer (9); and an NPN transistor (3) formed on the n-type epitaxial layer (26). The anode can be substantially completely depleted in the case where the anode layer (27) has its dopant concentration peak in the vicinity of the interface between the silicon substrate (1) and the n-type epitaxial layer (26). Therefore, high speed and high light receiving sensitivity characteristics can be obtained, and further, any influence of auto-doping from peripheral embedding layers can be controlled, so that a depletion layer can be stably formed in the anode.