Patent ID: 7154241

Claim:
A method for controlling an operation of a wiper by directing light emitted from a light emitting element to a detection area provided at a part of a wiper wiping region of a vehicular windshield glass, receiving light reflected on the detection area by a photo detector, and detecting a state of the detection area, comprising the steps of: (a) collecting water by a wiping operation; (b) detecting an amount of the collected water passing through the detection area; (c) detecting an impact of a raindrop on the detection area; (d) judging whether or not the amount of water passing through the detection area is not smaller than a predetermined threshold value; (e) judging whether or not the impact of the raindrop on the detection area is detected if the amount of water passing through the detection area is not smaller than the predetermined threshold value; and (f) carrying out control to decrease frequency of wiping operation of the wiper if the impact of the raindrop on the detection area is not detected.