热释电人体红外线传感器的基本结构和原理--毕业论文外文翻译.doc

The principle and application of Pyroelectric infrared sensor By John.ChurPyroelectric infrared sensor body (hereinafter referred to: sensor) from sensitive units, impedance converter and filter window of the three major components.1、Sensitive unit The different sensors, sensitive element of the material is different. If SD02 sensitive units made by the PZT; P2288 from LiTaO3 made. These materials to make thin sheet, each one of the two sides of the relatively thin lead an electrode, the electrodes at both ends of the formation of the equivalent of a small capacitor. Because these two small capacitor is done in the same silicon chip.And they form the equivalent of small capacitor can have its own polarization, the polarization of the result, the two ends of a capacitor in the opposite polarity of the positive and negative charge. But the capacitor is the polar opposite of the series. This is the unique design of the sensor, thus making it a unique and anti-jamming.When the sensor detects no radiation from the body of the infrared signal, as P1, P2 have its own polarization, the two ends of a capacitor in the opposite polarity, is the equivalent of electricity, negative charge, which the two capacitor is the opposite polarity The series, therefore, positive and negative charge to offset each other, not in the loop current, a sensor output.When the human body sensors detect static in the region, exposure to the P1, P2 on the infrared light energy equivalent, and achieve a balanced, polar opposite, the energy equivalent of light in the loop current offset each other. Sensors are still no signal output. Similarly, in the light or the sun, because the speed of the sun moving very slowly, P1, P2 on the infrared light energy can still be seen as equal and offsetting each other in the loop.Coupled with the low frequency response of the sensor (normally 0.110 Hz), that is, infrared sensors on the wavelength of light-sensitive a very narrow range (typically 515 um), therefore, the sensor is not sensitive to them.When the temperature change caused the temperature sensor itself changes, due to P1, P2 do the same silicon chip, it has the opposite polarity, and the energy equivalent of light in the still current in the loop offset each other, no sensor output.From the principles of perspective, any body will have an infra-red fever, pyroelectric infrared sensors on the body of the sensitivity of the main infrared sensors sensitive performance of the unit by the changes in temperature, and temperature changes lead to the formation of electrical signals. Environment and the temperature change from its own internal structure of its decision not outward output signal.The low-frequency response of the sensor (normally 0.110 Hz) and the specific wavelength infrared (normally 515 um) of the sensor response to a decision only on the outside of the infrared radiation caused by changes in temperature sensors and sensitive, and this change In terms of the human body is moving. Therefore, the sensor on human movement or the movement of sensitive, stationary or moving very slowly in the human body is not sensitive it can be most visible and infrared anti-interference.2、Filter windowIt is a thin glass coating on the multi-layer film from the filter, filter window can effectively filter out 7.014 um outside the infrared wavelengths. For example, SCA02-1,7.514 um wavelength infrared penetration of 70%, 6.5 um Department, dropped to 65 percent, while in 5.0 um, when decrease to 0.1%; P2288 response to the wavelength of 6 14 um, the center wavelength of 10 um.Launching objects to infrared radiation, the wavelength of the strongest and the relationship between temperature meetWhich was the largest wavelength, T is absolute temperature. The bodys normal body temperature is from 36 to 37.5, that is, 309310.5 K, its most powerful infrared radiation of wavelength The center wavelength is 9.65 um.Therefore, the body of the strongest infrared radiation at wavelengths just landed filter window response wavelength (714 um) at the centre. Therefore, the filter can effectively window to the human body through infrared radiation, and the maximum to stop the sun, lighting and so visible in the infrared through, so as to avoid interference.To sum up, only to mobile sensors or movement of the human body and the body temperature of objects similar to the human body works.Fresnel lens when not in use Fresnel lens sensor detection radius of less than 2 meters, with only the use of Fresnel lens can be most useful. With Fresnel lens when sensors detect a radius of up to 10 meters. For example, some sensors in the 20 meters far from the fast moving car in the human body can be reliably detected. Fresnel lens produced by a plastic plate.The lens measured in the horizontal direction into three parts, each part in a vertical direction and divided into a number of different regions. The top part of each Den fen as a lens unit, they constitute from one concentric circles, concentric circles in the center of the lens unit. Middle and the lower portion of each Den fen for a lens unit, respectively, from the same form concentric circles, but the center of concentric circles is not within the lens unit.When the light through the lens of these units, will be a dark-and visible areas and blind spots. Since each element of a lens only a small angle, for the foreseeable perspective, the perspective for the blind spot. Any two adjacent lens units are in a blind spot between that area and spacing of their intermittent without duplication and overlapping. In this way, when the lens on the front of the sensor is an appropriate location, movement in the event of a human body in front of the lens.Infra-red radiation to the human body through the lens in the sensor on the formation of the turn of the changes in the shadow of (blind spots) and bright (that), so that the surface temperature sensors constantly changing, so the output signal. This can also understand that human activities in the region detection, leaving a field of view lens unit, will immediately enter another field of view lens unit.Because neighboring close intervals between the lens unit), with a sensor on the body of the blind spot of mobile and visible, leading to changes in temperature sensor, and output signals. Fresnel lens that can not only create zones and blind spots, focusing, its focus is generally about five centimeters, the actual application, should be based on the actual situation or information provided to adjust Fresnel lens and the distance between sensors , The general sensor in the lens fixed in front of 1 to 5 cm in places.The general Fresnel lens made of polyethylene plastic film, for the color of milky white or black, with a translucent, but the wavelength of the infrared around 10 um, it is transparent.The pyroelectric infrared sensors basic human application PY1 sensor for the P2288 or SCA02-1, IC1 for low-noise amplifier LM358, such as high-speed computing. PY1 detected by the infrared signal the human body, from 2 feet out of the extremely weak signals with the direct input of the amplifier IC1a release about 2,500 times, from 1 foot a certain level of output signal, and then to the capacitive coupling C8 RP-amplifier IC1b further amplification. IC2 a window-type voltage comparators, when IC1b voltage range of 7 feet in Ua and the amplitude between the Ub, IC2 feet without output of 1、7 pin.When IC1b the magnitude greater than 7 feet voltage amplitude at the Ub, IC2 7 feet high-output when IC1b of less than 7 feet voltage amplitude at the Ua, IC2 feet of a high-output, the D1 , D2 mutual isolation and or the role of point output from the P HIGH control signals. R11 to set the threshold level window, adjust R11 can adjust the sensitivity of detectors. P high-point output control signals can be used for a variety of practical circuits.1、Have electricity and dangerous security alert for an electric circuit of the occasion, when someone access to these occasions, through the issue of voice and sound-to draw attention to safety.2、Automatic doors for major banks, guesthouses. When people came to when the door opens automatically, people to leave and then shut down automatically.3、Infra-red anti-theft alarm system for banks, office buildings, family occasions, such as the anti-theft alarm.4、Highway vehicle traffic counters5、Automatically opened, the Commissioner of the lights, close to the body automatically switches, etc.The principle and application of passive infrared detector In the electronic anti-theft, in the field of human detectors, passive pyroelectric infrared detector is widely used because of their low price, technical performance and stability by the vast number of users and professionals welcome.Passive pyroelectric infrared probe the working principle and characteristics:In nature, any more than absolute temperature (- 273 degrees) when the objects will have infrared spectrum, the objects at different temperatures, the release of the wavelength of infrared energy is not the same as, infrared wavelengths and the level is related to temperature .In a passive infrared detector has two key components, is a pyroelectric infrared sensors (PIR), it will be at 8 for a 12 um between the infrared signal changes into electrical signals, and can Nature of the white signal inhibited, passive infrared detector in the security area, when no human movement, the pyroelectric sensor infrared sensors to the background temperature is only when the human body into the warning area,Through the Fresnel lens, pyroelectric infrared sensor to sensor is the human body temperature and the temperature differences in background signals, so the infrared sensors detect the infrared sensors is the basic concept of moving objects and background differences in the temperature of the object .Another device is the Fresnel lens, the Fresnel lens has two forms, namely, refracting and reflecting. Fresnel lens has two roles: First, focus of the upcoming release of the thermal infrared signal refraction (reflection) in the PIR, the second role is to alert the region that is divided into several areas and dark areas, to alert District moving objects in a temperature change in the form of changes in the PIR on pyroelectric infrared signals, such changes can be generated from the PIR signals.Infrared sensors commonly used source of pyroelectric components, such components in the human body to receive infrared radiation temperature changes will be lost when the charge balance out the release of charge, follow-up testing after the circuit will be able to generate alarm signal.1、This body radiation detection probe is targeting. So pyroelectric components of the 10-micron wavelength was about to be very sensitive to infrared radiation. 2、For only the human body sensitive to infrared radiation, in its radiation cover usually covered with mud Seoul, the Philippine special filters, environmental interference by the apparent control.3、Passive infrared probe, the sensor consists of two serial or parallel between the pyroelectric. And the two electrodes made from the opposite direction, background radiation environment of the two components of pyroelectric almost have the same effect, to produce allay effect offset each other, so no signal output detector.4、Once intrusion detection within the region, the human body through the infrared radiation of the mirror focusing, and was receiving pyroelectric, but two pyroelectric receive different heat, pyroelectric different, can not be offset by the alarm signal processing.5、According to the Philippine soil Seoul filter performance requirements are different, with different focal length (from sensors), resulting in a different field of view monitoring, field of view, the more the more stringent control.Passive pyroelectric infrared probe the advantages and disadvantages. Is not in itself the merits of any type of radiation, the device power consumption is very small, concealed good and low prices. Drawback is:1、nerable to all kinds of heat, light interference.2、passive infrared penetration poor, the bodys infrared radiation easily be obscured, the probe was not easy to receive.3、vulnerable to interference from radio frequency radiation.4、temperature and close to body temperature, decreased sensitivity of detection and, sometimes resulting in short-term failure.Pyroelectric infrared sensor installation requirements.Pyroelectric infrared sensor can be installed only in the human body interior, its rate of false positives and the installation of the location and modalities for a great relationship The correct installation should meet the following conditions:1、Pyroelectric infrared sensors from the ground should be 2 to 2.2 meters. 2、Pyroelectric infrared sensor away from air conditioners, refrigerators, stoves and other changes in air temperature-sensitive areas. 3、Pyroelectric infrared sensors and detection by the human body may not be interval between the furniture, large potted plants, glass, curtains and other objects.4、Pyroelectric infrared sensors can not be allowed on the window, otherwise the window of hot air disturbance and personnel move will cause false positives, the best conditions of the curtain. Pyroelectric infrared sensors also do not want to install a strong airflow in the local activities. 附录3热释电人体红外线传感器的基本结构和原理约翰.库尔热释电人体红外线传感器（以下简称：传感器）由敏感单元、阻抗变换器和滤光窗等三大部分组成。1、敏感单元对不同的传感器来说，敏感单元的制造材料有所不同。如SD02的敏感单元由锆钛酸铅制成；P2288由LiTa03制成。这些材料再做成很薄的薄片，每一片薄片相对的两面各引出一根电极，在电极两端则形成一个等效的小电容。因为这两个小电容是做在同一硅晶片上的，而它们形成的等效小电容能自身产生极化，极化的结果是，在电容的两端产生极性相反的正、负电荷。但这两个电容的极性是相反串联的。这正是传感器的独特设计之处，因而使得它具有独特的抗干扰性。当传感器没有检测到辐射的红外线信号时，由于P1、P2自身产生极化，在电容的两端产生极性相反、电量相等的正、负电荷，而这两个电容的极性是相反串联的，所以，正、负电荷相互抵消，回路中无电流，传感器无输出。当人体静止在传感器的检测区域内时，照射到P1、P2上的红外线光能能量相等，且达到平衡，极性相反、能量相等的光电流在回路中相互抵消。传感器仍然没有信号输出。同理，在灯光或阳光下，因阳光移动的速度非常缓慢，P1、P2上的红外线光能能量仍然可以看作是相等的，且在回路中相互抵消；再加上传感器的响应频率很低（一般为0.110Hz），即传感器对红外光的波长的敏感范围很窄（一般为515um），因此，传感器对它们不敏感。当环境温度变化而引起传感器本身的温度发生变化时，因P1、P2做在同一硅晶片上的，它所产生的极性相反、能量相等的光电流在回路中仍然相互抵消，传感器无输出。从原理上讲，任何发热体都会产生红外线，热释电红外线传感器对红外线的敏感程度主要表现在传感器敏感单元的温度所发生的变化，而温度的变化导致电信号的产生。环境与自身的温度变化由其内部结构决定了它不向外输出信号；而传感器的低频响应（一般为0.110Hz）和对特定波长红外线（一般为515um）的响应决定了传感器只对外界的红外线的辐射而引起传感器的温度的变化而敏感，而这种变化对人体而言就是移动。所以传感器对人体的移动或运动敏感，对静止或移动很缓慢的人体不敏感；它可以抗可见光和大部分红外线的干扰。2、滤光窗它是由一块薄玻璃片镀上多层滤光层薄膜而成的，滤光窗能有效地滤除7.014um波长以外的红外线。例如SCA02-1对7.514um波长的红外线的穿透量为70%，在6.5um处时下降为65%，而在5.0um处时陡降为0.1%；P2288的响应波长为614um，中心波长为10um。物体发射出的红外线辐射能，最强波长和温度的关系满足其中为最大波长，T为绝对温度，人体的正常体温为3637.5，即309310.5K，其辐射的最强的红外线的波长为中心波长为9.65um。因此，人体辐射的最强的红外线的波长正好落在滤光窗的响应波长（714um）的中心。所以，滤光窗能有效地让人体辐射的红外线通过，而最大限度地阻止阳光、灯光等可见光中的红外线的通过，以免引起干扰。综上所述，传感器只对移动或运动的人体和体温近似人体的物体起作用。菲涅尔透镜不使用菲涅尔透镜时传感器的探测半径不足2米，只有配合菲涅尔透镜使用才能发挥最大作用。配上菲涅尔透镜时传感器的探测半径可达到10米。例如，一些传感器对远在20米处快速行驶的汽车里的人体也能可靠地检测到。菲涅尔透镜采用塑料片制作而成。透镜在水平方向上分寸成3个部分，每一部分在竖直方向上又