Patent ID: 7701503

Claim:
A method for controlling a light source in an optical input device for controlling an indicating position on a graphic display, comprising: setting a shutter ON time of an image sensor using a statistical value of an image obtained through the image sensor; setting a light source ON time in accordance with the shutter ON time and turning on/off the light source in response to the set light source ON time and turning on/off the shutter in response to the set shutter ON time and setting a light source ON period to be relatively longer than a shutter ON period; and when the image sensor becomes a shutter OFF state and data to be transmitted are present, controlling the light source to transmit the data from the optical input device to outside, wherein turning on/off the light source includes: turning on the light source first according to the light source ON time and then turning on the shutter according to the shutter ON time; and turning off the light source when the shutter is turned off, wherein setting the shutter ON time includes: calculating the statistical value of output signals of the image sensor, and comparing the calculated statistical value with a set statistical value.