1、热释电人体红外线传感器的基本结构和原理 外文翻译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, sens
2、itive 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. Be
3、cause 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 opp
4、osite 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 electricit
5、y, 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 equival
6、ent, 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 a
7、nd 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
8、 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 in
9、frared 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
10、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 term
11、s 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 fi
12、lter, 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 wa
13、velength 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 r
14、adiation 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 maxi
15、mum 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 l
16、ess 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
17、 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 l
18、ower 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 sm
19、all 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, m
20、ovement 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 sign
21、al. 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
22、 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
23、 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
24、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 time
25、s, 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
26、 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 R
27、11 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 dra
28、w 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 vehi
29、cle 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 be
30、cause 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
31、, 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 bet
32、ween 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 .
