Confocal sensing non contact measurement systems

Confocal sensors use polychromatic white light, which is focused onto a target object as a method to measure distance. The light undergoes chromatic deviation when it hits the target surface and, depending on the distance from the lens to the target object, the wavelength of the light that is focussed onto the target at the focal point can then be measured. This extremely accurate method of measuring distance is not even affected by the material, these sensors work equally as well on reflective backgrounds or even transparent materials such as glass. By expanding the colour spectrum that the sensor uses and the fact that the sensor has an extremely small spot size, measurements in the nanometre range can be easily achieved. One of the major benefits of using a Confocal sensor to measure the thickness of transparent materials is that only one sensor has to be used. This is due to the sensor being able to focus white light on the upper and lower surfaces of the transparent material. Both these distances can be evaluated and the thickness determined. Because Confocal sensors use light as the measuring medium, they can be affected by dust or debris particles getting in the way of the light path.