ELECTRONIC DESK TOP CALCULATOR

PURPOSE:To prevent a solar battery from generating a voltage to some degree or over by forming a specific segment to a part of a liquid crystal display device so as to cover a part or all of the solar battery, and controlling it with a voltage equal to a drive voltage. CONSTITUTION:The solar battery 22' is placed while being overlapped under the liquid crystal display device 21' and the specific segment pattern 30 of the liquid crystal display device 21' covers the entire face of the solar battery 22'. Since it is required to transmit light through the solar battery 22', the specific segment pattern 30 is not provided with a reflection plate but it is formed as transmission type. Through the constitution above, when the illuminance of the solar battery 22'is high and the voltage produced from the result approaches an upper limit voltage in the operating voltage range, the specific segment 30 formed to cover the solar battery is controlled by a voltage equal to a liquid crystal display drive voltage to reduce the transmitivity. Thus, the overvoltage generation of the solar battery is prevented.