Infrared LED lighting
The sensor was measured by the physical properties of the infrared. Infrared called infrared light, it has the reflection, refraction, scattering, interference, absorption properties. Any matter, so long as it has a certain temperature (more high than above absolute zero), can the infrared radiation. Infrared sensor measurement is not in direct contact with the measured object, so there is no friction, and has high sensitivity, fast response etc.. Infrared sensor comprises an optical system, a detection element and a conversion circuit. According to the structure of optical system can be divided into transmission type and reflection type two class. The detecting element according to the working principle can be divided into thermal detection device and the photoelectric detection component. The most widely used thermal element is a thermistor. Thermistor increase in temperature. the resistance to change, through the conversion into electrical signal output. Photodetector element commonly used is photosensitive element, usually made of lead sulfide, lead selenide, indium arsenide, arsenic, antimony, mercury cadmium telluride ternary alloys, germanium and silicon doped with other materials.Infrared sensors are commonly used in the non-contact temperature measurement, gas component analysis and nondestructive testing, is widely used in medical, military, space technology and environmental engineering. Such as the use of thermography infrared sensor distance measuring surface temperature of human body, can be found the temperature abnormal locations, timely diagnosis and treatment of diseases (see thermal imager); to monitor the earth clouds using infrared sensors on a satellite weather forecast, can realize large range weather forecast; using infrared sensor can detect the overheat condition when plane running engine。The human eye can see the visible light wavelength from long to short arrangement, followed by red, orange, yellow, green, cyan, blue, purple. The red light in the wavelength range of 0.62 to 0.76μm。 violet wavelength range of 0.38 ~ 0.46μm。 more short than Violet light wavelength is ultraviolet . To broadly speaking more long than red light wavelength is infrared. the sensor components can be a physical or chemical change amount to facilitate use of the electrical signal. infrared sensors is one of them. With the development of modern science and technology, the application of the infrared sensor has been very widely, with some examples below, briefly introduce the application of the infrared sensor. The working principle and characteristics of electric application and infrared sensor is a passive pyroelectric infrared probe of the human body heat released: the general human have a constant body temperature, generally at 37 degrees, so it will send a specific wavelength of 10UM infrared,the Fresnel will detecting and gather source that human body infrared emission around 10UM . Infrared sensors are usually used in pyroelectric element,
this element will be break balance of electric charge when the infrared radiation temperature changes, outward release charge, to generate an alarm signal.
1) the probe to detect human body radiation as the goal. So the pyroelectric element is very sensitive to the wavelength of the infrared radiation of about 10UM.
2) To only sensitive to infrared radiation of the human body, in the face of it and usually covered with Finil filter specia, so that the interference environment controlled by a significant role.
3) passive infrared detector, the sensor includes two mutually connected in series or parallel to the pyroelectric element. And made two electric polarization in opposite directions, environmental background radiation almost has the same effect on two pyroelectric element, make its produce pyroelectric effects offset each other, so no detector signal output.
4) once one intrusion detection area, human infrared radiation through partial mirror focusing, and the pyroelectric element is received, but two pyroelectric element received different heat, pyroelectric different, not offset by the signal processing and alarm.remote sensing as a large scope, high accuracy, quick access to information technology, will get more applications in the future technology development . Visible, sensors play a more and more important role in the field of science and technology, industrial and agricultural production and daily life. infrared sensors. As a part of them also will get larger development.