1. Field of Invention
The present invention relates to an outside element for a motor vehicle, the element providing a capacitive sensor, and the invention also provides a piece of bodywork including such an outside element.
2. Description of Related Art
In the state of the art, devices are already known for providing driving assistance on the basis of ultrasound radar.
Such devices provide good results but they are relatively expensive given their great complexity. That is why they are to be found almost exclusively on top-of-range vehicles only.
In addition, they are unsightly insofar as the radar transceiver must have a clear field of view in order to be able to operate. Given that such transceivers are generally housed in bumper shields, that requires the bumpers to be pierced, which gives rise to a certain amount of difficulty in organizing the appearance of the vehicle, and also to a certain amount of fragility for the sensors.
Furthermore, ultrasound sensors are relatively heavy at present and they provide a detection envelope that is not very uniform.
There is another artificial vision technique which makes it possible to detect movements of obstacles that might exist in the vicinity of a vehicle: detection by means of a capacitive sensor.
In that technique, an antenna is placed on the vehicle bumper so as to form a capacitor with each object around it, and thus in particular with any obstacles with which the vehicle might come into contact.
The distance between the antenna and each such object is one of the factors which determines the capacitance of the capacitor formed in this way. Consequently, by using electronic means to measure this capacitance it is possible to calculate the distance between the antenna and the object, or at least whether said distance is increasing or decreasing by measuring variations in the capacitance of the capacitor.
However, the difficulty with that technique lies in how the antenna is to be positioned on a piece of bodywork.