Patent ID: 6686603
Filing Date: 2004-02-03
Classification: B60S

Abstract:
A raindrop detection apparatus comprising:a light emitting device which emits light toward a windshield where a raindrop may be present; a light emitting device driving section supplying a power to the light emitting device; a photoreceptor which receives reflected light from the windshield, emitted from the light emitting device; an amplifying section amplifying a signal from the photoreceptor; and a control section detecting an amount of the raindrop on the windshield based on an output from the amplifying section as well as controlling operations of the light emitting device driving section and the amplifying section; wherein the control section includes: a first adjustment means which adjusts the output from the amplifying section to a predetermined target value by varying amplifying gains of the amplifying section, and a second adjustment means which adjusts the output to the target value by varying a power supplied from the light emitting device driving section to the light emitting device after the adjustment by the first adjustment means; and wherein the output adjustments performed by the first and the second adjustment means are programmed to execute output adjustment operations under a condition in which no raindrop or foreign substance is present on the windshield, the condition in which no raindrop or foreign substance is present on the windshield being created by mandatorily wiping the windshield.