Spectral confocal sensorThin lenses have different focal lengths for monochromatic light, and chromatic lens errors cause color spots or halos in the image. In photo records, special processing is required to minimize imaging problems caused by chromatic aberration lens errors. Commonly used removal methods are double bonding systems and double separation systems.

Spectral confocal sensor measurement methods take advantage of this physical phenomenon. The special lens is used to expand the focus halo range of light of different colors, and according to the distance from the different test elephant objects to the lens, a special magnification chromatic aberration is formed, so that the measurement elephant object can be focused. By measuring the wavelength of the reflected light, the exact distance from the measured object to the lens can be obtained. This process is the exact opposite of the process used by photographic agencies to reduce chromatic aberration in various ways.

In order to obtain this special chromatic aberration, several special lenses must be used within the sensor probe to break up the light according to the desired range. The light from the sensor probe is focused on one axis using a convex lens, forming the focusing axis. Without the use of a convex lens, the light from the sensor probe is scattered and cannot be measured.

The white light reaches the convex lens through the semi-mirror surface. The special chromatic aberration above happens here. When the light hits the object being measured, it reflects, passing through the convex lens and returning to the mirror lens inside the sensor probe. The reverse lens refracts the reflected light onto the perforated cover, and the small hole allows only the ideal reflected light to pass through the focal point.

The light passing through the perforated cover is a blurred spectrum. That is, light of different wavelengths can be irradiated on the CCD photosensitive matrix device through the small hole. However, only the reflected light focused on the measurement object has sufficient brightness to produce a distinct peak on the CCD photosensitive matrix.

A beamsplitter is required behind the perforated mask to measure the color information of the reflected light. A spectrometer is similar to a special grating that increases or decreases the refractive index depending on the wavelength of the reflected light. Therefore, each position in the CCD matrix corresponds to the distance of the measurement object to the probe.

Here, in order to generate the measurement signal, only the wavelength of the light is calculated. The peak amplitude of the signal produced by the reflected light of the spectral confocal sensor is not within the signal measurement criteria. That is, the brightness of the reflected light has no effect on the measurement results. That is, the measured distance result may remain the same regardless of the amount of reflected light reflected from the measured object. Because the intensity of the reflected light depends only on the reflectivity of the reflecting object. Therefore, this is true even if the object being tested with ERT's spectral confocal sensor is a strongly light absorbing material such as black rubber. Transparent materials, such as glass and liquids, can also be measured normally and reliably.