Handy terminal

Abstract

Abstract PURPOSE:To simplify the adjustment of contrast, and also, to eliminate a contact abrasion and a contact failure of a switch and a variable resistor by controlling the contrast of a liquid crystal display part in accordance with a power supply voltage and the temperature of use environment. CONSTITUTION:A main control part 1 calculates optimum data of contrast, transfers it to an I/O 15, and it is outputted to a D/A converter 14 from an output port of the I/O 15. The D/A converter 14 converts a digital signal to an analog signal and it is outputted to a liquid crystal driving circuit 11, and the contrast of the liquid crystal part is adjusted. In such a way, since the handy terminal body is provided with an automatic adjusting function of the contrast of the liquid crystal part, a switch and a volume are eliminated, and a fault to be caused by a contact failure is not generated. Also, such troublesomeness as an operator adjust the contrast each time due to the variation of voltage/temperature is eliminated.

Inventors

• 👤 Yoshitaka Enomoto
• 👤 榎本　良隆

Bibliographic Details