US 6,015,449 A · Rain drop detecting device

Abstract

A rain drop detecting device includes an oscillation element disposed on a plate member such as a windshield for generating an ultrasonic wave on the plate member, an ultrasonic wave receiving element disposed on the plate member for receiving the ultrasonic wave generated by the oscillation element, a detecting device connected to the ultrasonic wave receiving element for detecting an amplitude of the ultrasonic wave, and an ultrasonic wave absorbing member disposed on the plate member. The absorbing member is designed to absorb a portion of the ultrasonic wave generated by the oscillation element to prevent the downwardly travelling portion of the ultrasonic wave from travelling beyond a desired region of the plate member. In the case of a windshield, the absorbing member can be used to prevent the ultrasonic wave from travelling to the resting location of the wiper so that inadvertent rain drop detection does not occur.

Claims17

Dependent claims

A rain drop detecting device for detecting rain drops on a vehicle windshield, comprising:

an oscillation element disposed on a vehicle windshield for generating an ultrasonic wave on the windshield, the windshield having associated therewith a wiper which during non-operation is at a first location and which during operation moves across at least a portion of the windshield to remove rain drops;
an ultrasonic wave receiving element for receiving the ultrasonic wave generated by the oscillation element, the ultrasonic wave receiving element being disposed on the windshield in spaced apart relation to said oscillation element:
detecting means connected to the ultrasonic wave receiving element for detecting an amplitude of the ultrasonic wave received by the ultrasonic wave receiving element, with the amplitude of the ultrasonic wave received by the ultrasonic wave receiving element indicating a presence or absence of rain drops on the windshield;
and
an absorbing member for absorbing a portion of the ultrasonic wave which is generated by the oscillation element, the absorbing member being disposed on the windshield between the oscillation element and said first location.

2 more elements

Dependencies are inferred from the claim text.

Rain drop detecting device

Life of this patent

Rain drop detecting device

Life of this patent

Abstract

Claims17