Provided is an optically transparent plate having a structure where an LED die is directly mounted on an optically transparent substrate, and light extraction efficiency is improved. The optically transparent plate comprises, an optically transparent substrate, a wiring pattern placed on either of a surface on the upper side and a surface on the underside of the optically transparent substrate, or on both of the surfaces, and the LED die bonded to the wiring pattern. A reflective layer is placed on the other side, of the surface of the optically transparent substrate on which the LED die is mounted. At least a part of the wiring pattern and at least a part of the reflective layer comprise a conductive material obtained by sintering conductive particles.