热释电红外传感器中英文对照外文翻译文献

中英文对照翻译

热释电红外传感器

前言

热释电红外传感器是一种非常有应用潜力的传感器。它能检测人或某些动物发射的红外线并转换成电信号输出。早在1938年，有人就提出利用热释电效应探测红外辐射，但并未受到重视。直到六十年代，随着激光、红外技术的迅速发展，才又推动了对热释电效应的研究和对热释电晶体的应用开发。近年来，伴随着集成电路技术的飞速发展，以及对该传感器的特性的深入研究，相关的专用集成电路处理技术也迅速增长。

本文先介绍热释电传感器的原理，然后再描述相关的专用集成电路处理技术。

热释电效应

在自然界，任何高于绝对温度（-273K）的物体都将产生红外光谱，不同温度的物体释放的红外能量的波长是不一样的，因此红外波长与温度的高低是相关的，而且辐射能量的大小与物体表面温度有关。

可见光的波长通常在1μm以下，而1μm以上的光人眼是看不到的，但是可以通过适当的仪器对辐射的能量进行检测。

当一些晶体受热时，在晶体两端将会产生数量相等而符号相反的电荷，这种由于热变化产生的电极化现象，被称为热释电效应。通常，晶体自发极化所产生的束缚电荷被来自空气中附着在晶体表面的自由电子所中和，其自发极化电矩不能表现出来。当温度变化时，晶体结构中的正负电荷重心相对移位，自发极化发生变化，晶体表面就会产生电荷耗尽，电荷耗尽的状况正比于极化程度，图1表示了热释电效应形成的原理。

能产生热释电效应的晶体称之为热释电体或热释电组件，其常用的材料有单晶(LiTaO3 等)、压电陶瓷（PZT等）及高分子薄膜（PVFZ等）[2]

当以LiTaO3为代表的热释电材料处于自极化状态时，吸收红外线入射波后，结晶的表面温度改变，自极化也发生改变，结晶表面的电荷变得不平衡，把这种不平衡电荷的电压变化取出来，便可测出红外线。热释电材料只有在温度变化时才产生电压，如果红外线一直照射，则没有不平衡电压，一旦无红外线照射时，结晶表面电荷就处于不平衡状态，从而输出电压。

热释电红外线传感器因红外光线的照射与遮挡得到或失去热量，从而产生电压输出。从原理上讲应与波长无关，但由热释电材料做成的传感器有一个透光窗，而透光窗的选材与波长有关系。如以SiO2为窗材的传感器，它可以透过几乎全部的可见光，而有的窗材只能通过4μm附近波长的光，有的能透过6.1μm波长的光，有的能透过8μm~14μm波长的光，所以使用不同的窗材就可确认是哪个波长的光产生的热。

量子型的红外光探测器

量子型的红外光探测器与红外光的波长有关，它的特点是灵敏度高，响应速度快，响应的灵敏度与红外线波长有关。每个入射光子产生的能量

E=hc/λ=1124λ

式中，h——普朗克常数，h=4.14×10-15(evs)=6.625×10-34(JS) c——光速，c=3×1010cm/s

1μm红外光的能量为1.24eV，10μm红外光的能量为0.12eV，与可见光相比，红外线光的能量较小。量子型的红外传感器又分为光导电型和光电动势型两种。光导电型的组件材料有PbS、PbSe、Hg、Cd、Te等，它是利用红外线照射时阻抗减少的特点来获取检测信号的；

而光电动势型是在Ge、IrSb等半导体基片上形成PN结，当红外线照射时产生光电动势，Ge的禁带宽度为0.6ev，Ge二极管对0.6μm和1.9μm的红外光较敏感，当入射红外光的波长在0.6μm~1.9μm时，在PN结上形成的电动势随入射光量的增大而增大，从而经放大可输出探测电信号。

热释电传感器

热释电传感器利用的正是热释电效应，是一种温度敏感传感器。它由陶瓷氧化物或压电晶体组件组成，组件两个表面做成电极，当传感器监测范围内温度有ΔT的变化时，热释电效应会在两个电极上会产生电荷ΔQ，即在两电极之间产生一微弱电压ΔV。

热释电红外传感器和热电偶都是基于热电效应原理的热电型红外传感器?不同的是热释电红外传感器的热电系数远远高于热电偶。 结构图

热释电红外传感器的结构及内部电路见图2所示。

传感器主要有外壳、干涉滤光片、热释电组件PZT、场效应管FET等组成。

滤光片

人体辐射的红外线中心波长为9~10--um，而探测组件的波长灵敏度在0.2~20--um范围内几乎稳定不变。在传感器顶端开设了一个装有滤光镜片的窗口，这个滤光片可通过光的波长范围为7~10--um，正好适合于人体红外辐射的探测，而对其它波长的红外线由滤光片予以吸收，这样便形成了一种专门用作探测人体辐射的红外线传感器。 热电组件

将高热电材料制成一定厚度的薄片,并在它的两面镀上金属电极,然后加电对其进行极化,这样便制成了热释电探测元?由于加电极化的电压是有极性的,因此极化后的探测元也是

有正?负极性的?

内部的热电元由高热电系数的铁钛酸铅汞陶瓷以及钽酸锂?硫酸三甘铁等,其极化强度随温度的变化而变化?为了抑制因自身温度变化而产生的干扰可以在工艺上将两个特征一致的热电元反向串联或接成差动平衡电路方式, 以抑制由于自身温度升高而产生的干扰。因而能以非接触式检测出物体放出的红外线能量变化，并将其转换为电信号输出?

阻抗变换场效应管

热释电红外传感器在结构上引入场效应管的目的在于完成阻抗变换?由于热电元输出的是电荷信号，阻抗高达104MΩ,故引入的N沟道结型场效应管应接成共漏形式，即源极跟随器来完成阻抗变换?

由于它的输出阻抗极高，所以传感器中有一个场效应管进行阻抗变换。热释电效应所产生的电荷ΔQ会跟空气中的离子所结合而消失，当环境温度稳定不变时，ΔT=0，传感器无输出。当人体进入检测区时，因人体温度与环境温度有差别，产生ΔT，则有信号输出；若人体进入检测区后不动，则温度没有变化，传感器也没有输出，所以这种传感器能检测人体或者动物的活动。

选型参考

目前常用的热释电红外传感器型号主要有P228、LHl958、LHI954、RE200B、KDS209、PIS209、LHI878、PD632等。热释电红外传感器通常采用3引脚金属封装，各引脚分别为电源供电端(内部开关管D极，DRAIN)、信号输出端(内部开关管S极，SOURCE)、接地端(GROUND)。

热释电红外传感器的主要工作参数有

工作电压(常用的热释电红外传感器工作电压范围为3～15V) 工作波长(通常为7.5～14 μ m)

源极电压(通常为0.4～1.1V，R=47kΩ) 输出信号电压(通常大于2.0V)

红外模块使用注意事项：

1、人体感应器模块属于高度敏感的器件，它对电源要求很高，必须经过良好的稳压滤波，例如9V的层叠电池就可能因为内阻较大不能正常工作，建议客户用LM7808稳压芯片稳压后再通过220UF和0.1UF的电容滤波后供电。

2、模块不接负载时能正常工作，接上负载后工作紊乱，一种原因是因为电源容量很小负载比较耗电，负载工作时引起的电压波动导致模块误动作，另一种原因是负载得电工作时会产生干扰，例如继电器或者电磁铁等感性负载会产生反向电动势，315M发射板工作时会有电磁辐射等都会影响模块。解决办法如下：A、电源部分加电感滤波。B、采用负载和模块使用不同的电压的方法，例如：负载使用24V工作电压，模块使用12V工作电压，其间用LM7812三端稳压器隔离。C: 使用更大容量的电源。 3、人体感应器模块工作环境应该避免阳光、强光直接照射，若工作环境有强大的射频干扰，可采用屏蔽措施。若遇有强烈气流干扰，关闭门窗或阻止对流。感应区尽量避免正对着发热电器和物体，以及容易被风吹动的杂物和衣物

4、人体感应器模块必须装配在密封的盒里，否则一直会有输出信号。探头（PIR）与镜片有一聚焦距离，通常在20—30mm范围调整。

5、如果要求红外探测器的探测角度小于90度时，可以用不透明胶纸遮挡镜片或裁剪缩小镜片来实现。 6、人体感应器模块采用双元探头，人体的手脚和头部运动方向与感应灵敏度有着密切的联系，如果设置安装不当，会影响感应效果。

7、模块中的探头（PIR）可以装焊在电路板的另一面。也可将探头用双芯屏蔽线延长，长度应在2米以内为好。

结束语

热释电红外传感器具有价格低廉、技术性能稳定、开发使用简 单等特点，除了以上的监控报警和自动开关典型应用外，在众多其 它领域有广泛应用，如自动开停的空调机、饮水机、电视机、自动 拍摄人和动物活动的摄像机或数码相机等，随着电子技术发展，热 释电红外传感器必将更加广泛地应用在自动控制领域。

Pyroelectric infrared sensor

Preface

Pyroelectric infrared sensor is a very potential applications of the sensor.It can detect people or animals, the infrared transmitter and converted into anelectrical signal output. As early as 1938, it was proposed detection using pyroelectric infrared radiation effect, but not taken seriously. Until the sixties, with the laser, infrared technology is developing rapidly, it has contributed tothe pyroelectric effect and research on pyroelectric crystals application development. In recent years, along with the rapid development of integrated circuit technology, as well as the characteristics of the sensor depth study of the relevant application

specific integrated circuit processing technology is also growing rapidly.

This article first describes the principle of the pyroelectric sensor, and then

describe the relevant ASIC processing technology.

Pyroelectric effect

In nature, any more than the absolute temperature (-273K) objects will have

infrared spectra, objects at different temperatures the wavelength of infrared energy released is not the same, so the level of infrared wavelengths is related to temperature, and radiation energy size and surface temperature.

1μm wavelength of visible light is usually less, but more than 1μm light the human eye can not see, but can be an appropriate instrument to detect the energy oradiation.

When some of the crystal is heated, the crystal will have an equal number of both ends of the opposite sign of charge, such as heat of changes in the polarization phenomenon, known as the pyroelectric effect. Typically, the crystals produced by the spontaneous polarization bound charge is attached to the air from the surface of free electrons in the crystal and in its spontaneous polarization electric moment can not be

demonstrated. When the temperature changes, positive and negative charges in the crystal structure of the relative center of gravity shifts, the spontaneous polarization changes, the crystal surface will have run out of charge, charge depletion is proportional to the polarization degree of the situation, Figure 1 shows the pyroelectric The principle effect of the formation.

Pyroelectric effect can produce a crystal or call the pyroelectric pyroelectric

body components, the material commonly used in single crystal (LiTaO3, etc.), piezoelectric ceramic (PZT, etc.) and polymer film (PVFZ, etc.) [ 2]

When represented LiTaO3 pyroelectric material is self-polarized state, the absorption of infrared incident, the crystallization of the surface temperature change, since the polarization has changed, crystal surface charge becomes imbalanced, the imbalance taken out of charge voltage can be measured by infrared. Pyroelectric materials produced only when the temperature changes the voltage, if the infrared radiation has been, there is no imbalance in voltage, if no infrared radiation, the crystal surface charge on the in an unbalanced state, so the output voltage

Pyroelectric infrared sensors, infrared light irradiation due to gain or lose

heat and shelter, resulting in voltage output. In principle should be independent of the wavelength, but the material made by the pyroelectric sensor has a light transmission window, the translucent windows and wavelength selection of a relationship. To SiO2 as the window material, such as sensors, it can almost all visible light, while others near the window material can only 4μm wavelength of light, and some wavelengths of light through 6.1μm, and some through 8μm ~ 14μm wavelength of light, so use a different window materials which can be confirmed that the heat generated by the wavelength of light.

Quantum-type infrared detector

Quantumponse, response sensitivity and infrared wavelength. The energy generated by each incident photon E = hc / λ = 1124λ

Where, h - Planck constant, h = 4.14 × 10-15 (evs) = 6.625 × 10-34 (JS) c - the speed of light, c = 3 × 1010cm / s

1μm infrared light energy 1.24eV, 10μm infrared light energy of 0.12eV,

compared with the visible light, infrared light energy smaller. Quantum-type infrared sensor light conductive type and is divided into two kinds of light force. Components of light conductive material PbS, PbSe, Hg, Cd, Te, etc., it is the use of infrared radiation to reduce the characteristics of impedance detection signal to obtain; and light force type is in Ge, IrSb formed on a substrate such as semiconductor PN Results, when the infrared radiation generated when the light force, Ge band gap for the 0.6ev, Ge diode of 0.6μm and 1.9μm more sensitive to infrared light, infrared light when the wavelength of the incident in the 0.6μm ~ 1.9μm, in the PN junction force formed with the increase of the amount of incident light, thereby detecting amplified output signal.

Pyroelectric sensor

Pyroelectric

sensor

using

the

pyroelectric

effect

is,

is

a

temperature-sensitive sensor. It consists of oxides or ceramic piezoelectric crystal components, the component made of two surface electrodes, when the temperature within the sensor monitoring the change ΔT, the pyroelectric effect in the two electrodes will produce the charge ΔQ, ie between two electrodes in a weak voltage ΔV.

Pyroelectric infrared sensors and thermocouples are based on the principle of

thermoelectric thermoelectric infrared sensors. Different pyroelectric infrared sensors is the thermoelectric coefficient is much higher than the thermocouple.

Chart

Pyroelectric infrared sensor structure and the internal circuit shown in Figure

2.

Sensors are mainly case, interference filters, pyroelectric component PZT,

FET, FET and other components.

Filter

Human central wavelength of infrared radiation 9 ~ 10 - um, the wavelength

sensitivity of the detection component in 0.2 ~ 20 - um range is almost constant. The top of the sensor chip has opened a window with filter, this filter through the wavelength range of 7 ~ 10 - um, just right for the detection of infrared radiation in the human body, while the other infrared wavelengths by the filter film to be absorbed, thus forming a special body for detection of infrared radiation sensor. Thermoelectric components

Thermoelectric materials will be a certain thickness of the sheet, and in its metal electrodes deposited on both sides, and then power on its polarization, this will

make the pyroelectric detectors. As the voltage increases polarization is extremely nature and therefore, the detection element is polarized positive 、 negative in nature.

Thermoelectric element within the Seebeck coefficient by the high iron titanate ceramic lead and mercury, and lithium tantalate 、 Triglyceride iron sulfate, and its polarization changes with temperature. In order to suppress the temperature change due to their interference can be generated process will be the same two features reverse thermoelectric element connected in series or poor way of balancing the circuit, to suppress its own temperature as a result of the interference. Thus able to detect objects in non-contact infrared energy emitted changes and converts it to electrical signal output.

FET impedance transformation

Pyroelectric infrared sensors in the structure aims to introduce complete FET

impedance transformation. Thermoelectric element as is the charge output signal, resistance up to 104MΩ, so the introduction of the N-channel JFET common drain pipe should be connected in the form of that the source follower to complete the impedance transformation.

Because of its high output impedance, so the sensor has a field effect

transistor for impedance transformation. Pyroelectric effect will be produced by the charge ΔQ with combination of ions in the air disappeared, when the ambient temperature stability constant, ΔT = 0, the sensor no output. When the body into the detection zone, because the body temperature and ambient temperature differential, resulting in ΔT, is a signal output; if the body does not move into the detection zone, the temperature does not change, the sensor has no output, so this sensor can detect body or animal activities.

Reference Selection

The commonly used models of pyroelectric infrared sensors are P228,

LHl958, LHI954, RE200B, KDS209, PIS209, LHI878, PD632 and so on. Pyroelectric

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