Explain the principle of photoelectric sensor detection and what are the applications

For general acoustic emission applications, the signal frequency band range is mostly between 25kHz and 750kHz, so resonant sensors are more suitable. Resonant narrowband sensors with a general broadband frequency of 150kHz are commonly used for metal materials and other applications; For acoustic emission signals such as corrosion and leakage, resonant sensors with a resonant frequency of 40kHz are commonly used; Due to the relatively low response sensitivity of wideband sensors in a wide frequency band, wideband sensors are selected for spectrum analysis. Qingcheng acoustic emission sensor is made of high-quality stainless steel material, and the overall shielding design can effectively reduce interference; It is suitable for bridge wire fracture monitoring, valve pipeline leakage monitoring, tool wear monitoring, wind power equipment monitoring, rotating equipment acoustic emission monitoring, structural parts damage monitoring, storage tank floor acoustic emission monitoring.

The basic principle of photoelectric sensors is material (electro-optic reaction).

The photoelectric effect is a very important and magical phenomenon, simply put, it refers to the irradiation of photons of a certain frequency, the electrons inside some substances will be excited by photons to form an electric current, from the perspective of energy conversion, this is a photoelectric generation, light energy into electrical energy process.

The formula for the photoelectric effect: HV=EK+W.

where Hv is the energy carried by a photon with a light frequency of V, H is Planck's constant, V is the frequency of a photon, Ek is the maximum initial kinetic energy of an electron, and W is the work of escape of the excited substance.

Photoelectric sensors are sensors that use optoelectronic components as detection elements. It first converts the measured change into a change in the optical signal, and then further converts the optical signal into an electrical signal with the help of an optoelectronic component. Photoelectric sensors are generally composed of three parts: light source, optical path and optoelectronic components.

Photoelectric sensors are controlled by converting changes in light intensity into changes in electrical signals.

The emitted beam of the transmitter is generally the same as that of the semiconductor light source, which is aimed at the target and continuously emits the beam or changes the pulse width; The receiver is composed of a photodiode, a phototransistor, and a photocell; The detection circuit filters out the valid signal and applies the signal.

Main areas of application of photoelectric sensors:

In-car entertainment navigation *** The backlight control of the system is convenient to display the ideal backlight brightness in all ambient light conditions. Display backlight control for rear-seat entertainment, instrument cluster backlight control (speedometer, tachometer), automatic rearview mirror brightness control (usually requires two sensors, one forward-facing and one rear-facing), automatic headlight and rain sensor control (dedicated, changes according to demand), rearview camera control (dedicated, changes according to demand).

It has become one of the most effective solutions in terms of providing more comfortable display quality, with properties similar to those of the human eye, which is critical for automotive applications that require full backlighting in all ambient light conditions.

1. A photoelectric sensor is a device that detects the distance and presence of an object by using an optical emitter (usually an infrared emitter) and an optoelectronic receiver. Photoelectric sensors are widely used in industrial manufacturing. There are three common types of photoelectric sensors:

Counter type (transmissive), reflective type, and close-range detection type (diffuse reflective type).

2. What are the types of sensors?

1) Laser, a measuring device that uses laser technology. It consists of a laser, a laser detector, and a measurement circuit. It is a new type of measuring instrument, which has the advantage of being able to achieve non-contact remote measurement, and has the advantages of speed, high precision, strong anti-light and anti-interference ability.

2) Resistive type, which is a device that converts measured physical quantities such as displacement, deformation, force, acceleration, humidity, temperature, etc. into resistance values.