The photoelectric sensor is generally composed of two parts: a processing path and a processing element. The basic principle is based on the photoelectric effect, which converts the measured changes into optical signal changes, and then further converts non-electrical signals into electrical signals with the help of photoelectric elements. The photoelectric effect refers to illuminating an object with light, which can be seen as a series of photons with a certain energy bombarding the object. At this time, the photon energy is transferred to the electron, and the entire energy of a photon is all at once. When the electron is absorbed, the state of the electron will change after it gets the energy transferred by the photon, so that the object irradiated by the light will produce the corresponding electric effect. The photoelectric effect is usually divided into 3 categories:

(1) The phenomenon that electrons can escape from the surface of an object under the action of light is called external photoelectric effect, such as photoelectric tube, photomultiplier tube, etc.;

(2) The phenomenon that the resistivity of an object can be changed under the action of light is called the internal photoelectric effect, such as photoresistors, phototransistors, etc.;

(3) Under the action of light, the phenomenon that an object generates an electromotive force in a certain direction is called the photovoltaic effect, such as a photovoltaic cell.

 

 

The photoelectric detection method has the advantages of high accuracy, fast response, non-contact, etc., and has many measurable parameters. The sensor has a simple structure and flexible forms. Therefore, photoelectric sensors are widely used in detection and control.

 

The photoelectric sensor is the key element to realize photoelectric conversion in various photoelectric detection systems. It is a device that converts light signals (visible and ultraviolet laser light) into electrical signals.

The photoelectric sensor is a sensor that uses a photoelectric device as a conversion element. It can be used to detect non-electrical physical quantities that directly cause changes in light quantity, such as light intensity, illuminance, radiation temperature measurement, gas composition analysis, etc.; it can also be used to detect other non-electrical quantities that can be converted into light quantity changes, such as part diameter, surface roughness, Strain, displacement, vibration, speed, acceleration, as well as the recognition of the shape and working state of the object, etc. Photoelectric sensors have the characteristics of non-contact, fast response, reliable performance, etc., so they are widely used in industrial automation devices and robots. The emergence of new photoelectric devices, especially the birth of CCD image sensors, has opened a new page for the further application of photoelectric sensors.