Xike Sick Sensor Zhejiang General Agent

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SICK sensors are sensors that use optoelectronic components as detection elements. It first converts the measured changes into changes in optical signals, and then further converts the optical signals into electrical signals using optoelectronic components. A photoelectric sensor generally consists of three parts: a light source, an optical path, and a photoelectric element. There are various optical measurement and control systems made based on the principle of the effect of light flux on photoelectric elements. According to the output properties of photoelectric elements (optical measurement and control systems), they can be divided into two categories: analog photoelectric sensors and pulse (switch) photoelectric sensors Analog photoelectric sensor converts the measured photoelectric sensor into a continuously changing photocurrent, which has a single value relationship with the measured signal Analog photoelectric sensors can be divided into three categories based on the method of being measured (detecting target objects): transmission (absorption), diffuse reflection, and shading (beam blocking) The so-called transmission type refers to the situation where the measured object is placed in the optical path, and the light energy emitted by a constant light source passes through the measured object, partially absorbed, and the transmitted light is projected onto the photoelectric element; The so-called diffuse reflection type refers to the light emitted by a constant light source projected onto the object being measured, and then reflected from the surface of the object being measured and projected onto the photoelectric element; The so-called shading type refers to the situation where a portion of the luminous flux emitted by the light source is blocked by the measured object, causing a change in the luminous flux projected onto the photoelectric element. The degree of change is related to the position of the measured object in the optical path Photodiodes are common light sensors. The appearance of a photodiode is the same as that of a general diode, except that there is a window embedded with glass on its shell for light to enter. In order to increase the light receiving area, the PN junction area is made larger. The photodiode works in a reverse biased working state and is connected in series with a load resistor. When there is no light, it is the same as a regular diode, and the reverse current is very small (<µ A), which is called the dark current of the photodiode; When illuminated, charge carriers are excited, producing electron hole pairs, known as charge carriers in photoelectric sensors. Under the action of an external electric field, photoelectric carriers participate in conduction, forming a much larger reverse current than dark current, which is called photocurrent. The magnitude of photocurrent is directly proportional to the intensity of light, so an electrical signal that varies with the intensity of light can be obtained on the load resistor. In addition to the function of converting light signals into electrical signals through photodiodes, phototransistors also have the function of amplifying electrical signals. The appearance of a photosensitive transistor is not much different from that of a general transistor. Generally, a photosensitive transistor only has two emitter and collector electrodes, and the base electrode is not led out. The tube shell also has a window for light to enter. To increase the illumination, the base area is made large, the emission area is small, and the incident light is mainly absorbed by the base area. During operation, the collector junction is reverse biased and the emitter junction is forward biased. The current flowing through the transistor in the absence of light is the dark current Iceo=(1+β) Icbo (very small), which is smaller than the penetration current of a typical transistor; When illuminated, a large number of electron hole pairs are excited, causing an increase in the current Ib generated at the base. The current flowing through the transistor at this moment is called photocurrent, and the collector current Ic=(1+β) Ib. It can be seen that phototransistors have higher sensitivity than photodiodes.