Photoeye sensor is a device that converts optical signals into electrical signals. Its working principle is based on the photoelectric effect. The photoelectric effect means that when light is irradiated on some material, the electrons of the material absorb the energy of the photon and the corresponding electric effect occurs. According to the different phenomena of photoelectric effect, the photoelectric effect is divided into three categories: external photoelectric effect, internal photoelectric effect and photovoltaic effect. Photoelectric devices include phototubes, photomultiplier tubes, photoresistors, photodiodes, phototransistors, photocells, etc.
Photoeye sensor is generally composed of two parts: processing path and 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 three categories: (1) The phenomenon that can cause electrons to overflow the surface of the object under the action of light is called the external photoelectric effect, such as photoelectric tube, photomultiplier tube, etc.; (2) The phenomenon that can make the object under the action of light The phenomenon of the change of resistivity is called the internal photoelectric effect, such as photoresistor, phototransistor, etc.; (3) The phenomenon that an object generates a certain directional electromotive force under the action of light is called the photovoltaic effect, such as photovoltaic cells.

The photoelectric detection method has the advantages of high precision, fast response, non-contact, etc., and there are many measurable parameters, the structure of the sensor is simple, and the form is flexible and diverse. Therefore, the Photoeye sensor is widely used in detection and control.
Photoeye sensor is a key component of photoelectric conversion in various photoelectric detection systems. It is a device that converts optical signals (visible and ultraviolet laser light) into electrical signals.