CN113363335A

CN113363335A - Infrared sensor

Info

Publication number: CN113363335A
Application number: CN202010104753.2A
Authority: CN
Inventors: 李吉光; 徐一舟; 冯雪
Original assignee: Hangzhou Fuzhou Photoelectric Co ltd
Current assignee: Hangzhou Fuzhou Photoelectric Co ltd
Priority date: 2020-02-20
Filing date: 2020-02-20
Publication date: 2021-09-07

Abstract

An infrared sensor comprises an infrared lens, a packaging shell, a substrate, a sensing chip, a micro-lens array, a storage chip, pins and the like, wherein the sensing chip comprises a sensing array and a signal processing circuit, the sensing array comprises a sensing part and a signal conversion and control part, the sensing part converts optical signals into electrical signals related to temperature, the sensing part adopts a thermopile pixel array using a nano material as an absorption layer, a micro lens array is arranged above the sensing pixel array, the micro lens array focuses incident infrared signals to an infrared absorption layer in the pixel, the signal processing part comprises an ambient temperature detection module, the storage chip is used for pre-storing ambient temperature coefficients, the signal processing and control part processes the electrical signals, and calibrating and converting the digital voltage signal output by the analog-to-digital voltage conversion module and the set output standard digital voltage signal.

Description

Infrared sensor

Technical Field

The invention relates to the field of infrared detectors, in particular to an infrared detector for a thermopile.

Background

With the development of the internet of things technology, the life quality of people is improved, the application prospect of the infrared detector is more and more extensive, and the infrared thermopile infrared detector in the thermal infrared detector occupies a certain market position due to high sensitivity and low manufacturing cost.

The infrared thermopile is constructed by mutually connecting two materials with different Seebeck coefficients in series based on a Seebeck effect mechanism, one end with higher temperature in the two series parts is generally called as a hot end, the other end with lower temperature is called as a cold end, current carriers in the materials move along the direction of reducing temperature gradient to cause charge accumulation at the cold end, at the moment, voltage is generated in a loop, and a plurality of pairs of thermocouples are usually adopted in application.

At present, the thermopile structure generally adopts the film structure to play good thermal-insulated effect, the infrared absorbed layer reinforcing of large tracts of land is adopted to the hot end promptly and is absorbed, keeps apart with other parts of substrate through cantilever isotructure.

The lower part of the film needs to form a heat insulation cavity to avoid the absorbed heat from being quickly dissipated in the substrate, the formation of the heat insulation cavity is generally completed by adopting a sacrificial layer releasing process, two main processes of front surface releasing and back surface releasing are available, and the device of the front surface releasing thermopile structure process has the defects of structural adhesion, low performance and the like, so that the thermopile infrared detector manufactured by adopting the MEMS technology is mostly released from the back surface of a silicon wafer, and the heat insulation cavity released from the back surface penetrates through monocrystalline silicon to the bottom of the silicon substrate.

When infrared light enters the infrared thermopile from the outside, a part of infrared light enters the hot end infrared absorption layer to be absorbed, so that voltage is generated due to temperature difference between the infrared light and the cold end, a part of infrared light passes through the chip through a gap of the heat insulation cavity generated by the cantilever and other structures and cannot be utilized, a part of infrared light enters the substrate part comprising the cold end and the reading circuit, the absorption rate of monocrystalline silicon for infrared light of the manufactured substrate is low, but silicon processed by CMOS can absorb infrared light to generate heat, so that noise and errors are caused.

Disclosure of Invention

The present application is directed to avoid the above-mentioned deficiencies of the prior art by incorporating a polished metal sheet beneath the substrate to reflect back infrared light transmitted through voids and the like, to improve infrared absorption, and to quickly dissipate heat generated in other areas of the substrate.

The purpose of the invention is realized by adopting the following technical scheme:

the infrared sensor comprises an infrared lens, a packaging shell, a substrate, a detection chip, a storage chip, a metal sheet, pins and the like, wherein the detection chip comprises an induction array, a signal processing circuit (including but not limited to a signal amplifier, an analog-digital voltage converter, a register) and the like, the induction array comprises an induction part and a control part, the induction part converts optical signals into electric signals related to temperature and can detect ambient temperature for signal comparison processing, the induction part adopts the infrared detection chip which uses a multi-layer composite film comprising nano materials as an absorption layer, and the control part and the storage core are used for calculating an ambient temperature coefficient according to a pre-stored rule and calibrating and converting between digital voltage signals output by the analog-digital voltage conversion chip and set output standard digital voltage signals.

The detection chip of the thermopile infrared detector is characterized in that sensing pixels of a sensing array of the detection chip comprise monocrystalline silicon, a composite film layer, a thermocouple layer, an insulating medium layer, a metal pattern layer, an infrared absorption layer, a high-reflection heat dissipation layer and the like, the composite film layer grows on the upper surface of the monocrystalline silicon layer, the thermocouple layer grows on the composite film layer and consists of thermocouples connected in series, a thermocouple material is formed by connecting heavily doped N-type polycrystalline silicon and heavily doped P-type polycrystalline silicon in a paired mode, the N-type polycrystalline silicon is connected with the heavily doped P-type polycrystalline silicon through aluminum, the insulating medium layer grows on the thermocouple layer, the metal pattern layer is formed on the insulating medium layer and comprises electrodes, leads and the like, so that the P-type polycrystalline silicon and an N-type polycrystalline silicon resistance block are connected to form a thermopile, the P-type polycrystalline silicon and the N-type polycrystalline silicon resistance block penetrate through the insulating layer to be connected with the polycrystalline silicon and the like through photoetching technology and the like in the middle, the cold end and the hot end of the thermopile layer are connected with the outside at the metal graphic layer by using aluminum electrodes, the infrared absorption layer grows on the upper surface of the hot end of the thermopile, the high-reflection heat dissipation layer grows on the upper surface of the cold end of the thermopile layer, a groove is formed in the bottom of the infrared detector to form a heat insulation cavity, the heat insulation cavity penetrates through monocrystalline silicon to expose the composite film layer, and the local part of the thermopile thermocouple layer is positioned in the heat insulation cavity.

The infrared absorption layer with high absorptivity is added in the infrared radiation receiving area of the hot end of the sensing pixel of the thermopile, and the high reflection heat dissipation layer is added on the cold end, so that the temperature difference between the cold end and the hot end of the thermocouple is improved, the output of sensing voltage is improved, and the sensitivity of the device is improved.

The lens, the thermopile sensing chip, the memory chip and the like are integrally packaged on the substrate, wherein a polished metal sheet is added between the substrate and the packaging base under the substrate of the sensing chip to reflect infrared rays penetrating through gaps and the like, so that the infrared ray absorption rate is improved, and heat generated in other areas of the substrate can be rapidly led out.

The technical scheme of the application has the advantages that,

(1) the metal effectively reflects infrared rays, and the metal sheet can reflect infrared rays passing through the upper hot area back to the hot area, so that the absorption efficiency of the infrared absorption layer in the hot area is improved.

(2) When the chip silicon substrate (cold area) is irradiated by infrared rays to generate heat, the heat can be quickly led out to areas such as a packaging base and the like by a metal sheet with excellent heat conductivity, and the temperature difference between the cold area and the hot area is improved, so that the signal-to-noise ratio is improved, and the performance of the thermopile is improved.

(3) The infrared absorption layer with high absorptivity is added in the infrared radiation receiving area at the hot end of the thermopile, and the high-reflection heat dissipation layer is added on the cold end, so that the temperature difference between the cold end and the hot end of the thermocouple is increased, the output of induced voltage is improved, and the sensitivity of the device is improved.

(4) The reliability of the device is improved, and the device has the advantages of easiness in use and high cost performance.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

included in figure 1 are: the infrared sensor comprises an infrared lens 101, an infrared sensing array 102, an infrared signal processing circuit 103, a packaging tube cap 104, a bonding wire 105, a memory chip 106, a base 107, a pin 108 and a metal sheet 109. The thermopile infrared sensor further comprises a base 107, a thermopile infrared sensing array device 102, a signal processing circuit chip 103 and a memory chip 106 which are both positioned on the upper surface of the base 107, wherein the thermopile infrared sensing array device 102, the signal processing circuit chip 103 and the memory chip 106 are separated by a certain distance; the top of the pipe cap 104 is provided with a through hole, and the infrared lens 101 is fixed on the pipe cap 104 and completely covers the through hole.

Fig. 2 is a schematic structural diagram of a sensing pixel of the infrared detector of the present application; in the figure, 201 is a monocrystalline silicon substrate, 202 is a composite film layer, 203 is a thermocouple layer, 204 is an insulating medium layer, 205 is a metal pattern layer, 206 is an infrared absorption layer, 207 is a high-reflection heat dissipation layer, 208 is a heat insulation cavity, 209 is a light-reflecting metal sheet, 2010 is a reading circuit module, 203-1 is heavily doped P-type polycrystalline silicon of a thermocouple, 203-2 is heavily doped N-type polycrystalline silicon of the thermocouple, and the reading circuit module is connected with the metal pattern layer (including a metal electrode).

Fig. 3 is a schematic diagram of an infrared absorption layer and a heat dissipation layer with high reflection according to an embodiment of the present invention, in which 306 is an infrared absorption layer region, 307 is a heat dissipation layer region with high reflection, and other reference numerals are the same as those in fig. 2.

Fig. 4 is a schematic diagram of a sensing chip of an infrared detector according to the present invention, in which a plurality of sensing pixels are provided, each pixel is connected to a readout circuit through a metal electrode, the readout circuit is partially located outside the sensing pixels, and partially located in the gaps between the sensing pixels, and the reference numerals in the drawing are the same as those in fig. 2 and 3.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus once an item is defined in one figure, it is not further defined and explained in subsequent figures.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

Reference in the specification to "various embodiments," "in an embodiment," "one embodiment," or "an embodiment," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in various embodiments," "in some embodiments," "in one embodiment," or "in an embodiment," or the like, in places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, a particular feature, structure, or characteristic illustrated or described in connection with one embodiment may be combined, in whole or in part, with features, structures, or characteristics of one or more other embodiments without presuming that such combination is not an illogical or functional limitation.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that are conventionally placed when products of the present application are used, and are used only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is further noted that, unless expressly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

The invention provides an integrated infrared sensor, as shown in the attached figure 1, comprising:

an infrared sensor chip;

a metal light reflecting sheet;

a memory chip;

an infrared lens;

in order to meet the packaging and connection requirements in practical application, the thermopile infrared sensor further comprises:

the tube cap covers the top of the base and is positioned at the periphery of the infrared sensor chip and the storage chip;

the infrared sensor chip and the storage chip are both positioned on the upper surface of the base, and the infrared sensor chip and the storage chip are separated by a space;

a metal reflector is arranged between the bottom of the infrared sensor chip and the substrate;

wherein the infrared lens is fixed on the pipe cap and completely covers the through hole.

The chips are connected through bonding wires.

The connection between the various parts is achieved in a manner common in the art.

Before the infrared sensor is packaged, a worker calculates digital voltage signals output by a sensing chip obtained through testing and set output standard voltage signals according to a preset rule, so that a corresponding ratio is obtained and is used as a calibration coefficient and stored in a storage chip, and then the storage chip stored with the calibration coefficient, a lens and the sensing chip are integrally packaged and formed on a circuit board. The lens collects external infrared signals, focuses the external infrared signals to the sensing array, converts the external infrared signals into voltage signals after photoelectric conversion and amplification, and the sensing chip processing module can directly call the correction coefficient in the storage chip and calibrate the digital voltage signals output by the analog-to-digital voltage conversion chip according to the correction coefficient, so that the infrared sensor can output the calibrated digital voltage signals to corresponding equipment after being connected with a corresponding interface system, and calculation of different scenes is met.

The infrared sensing chip part comprises a sensing array, wherein the sensing array is X n rows of m, m and n are integers, m arrays are formed, and each row comprises n pixels. The pixel output is a voltage signal on the order of microvolts (μ V), and in a preferred embodiment, m =16, n =16, a = 4.

The sensing pixels are of a thermopile MEMS structure, and each pixel is electrically connected with a readout circuit (comprising a signal processing circuit).

Each infrared detection pixel comprises monocrystalline silicon, a composite film layer, a thermocouple layer, an insulating medium layer, a metal pattern layer, an infrared absorption layer, a high-reflection heat dissipation layer and the like.

The operating principle of the thermopile infrared detection pixel is as follows: the suspended sensitive surface of the composite dielectric film 202 and the infrared absorption layer 206 thereon absorb heat to form a temperature gradient with other parts of the device, the part of the suspended sensitive surface is regarded as the hot end of the thermopile, and the silicon substrate 201 is regarded as the cold end of the thermopile, so that the intensity of incident heat can be directly measured by the magnitude of output voltage of the thermopile, in order to improve the heat absorption rate of the sensitive surface and ensure the sensitivity of output signals, the infrared absorption layer 206 can be added on the upper surface of the sensitive surface, the high-reflection heat dissipation layer 207 is added on the silicon substrate, the difference between the cold end and the hot end is improved, the effects of fully absorbing heat and improving strength are achieved, and the sensitivity of signals is improved.

The composite film layer grows on the upper surface of the monocrystalline silicon layer, the composite dielectric film is formed by compounding single-layer or multi-layer silicon oxide and silicon nitride, the composite dielectric film 202 can be formed by adopting methods such as thermal oxidation, Low Pressure Chemical Vapor Deposition (LPCVD), Plasma Enhanced Chemical Vapor Deposition (PECVD) and the like, and the shape of the composite film can be formed by a photoetching process.

The thermocouple layer grows on the composite film layer and consists of thermocouples connected in series, the thermocouple material is formed by connecting heavily doped N-type polycrystalline silicon and heavily doped P-type polycrystalline silicon in a pair mode, the thickness of the polycrystalline silicon is 1-10 mu m, the line width is 1-20 mu m, the distance between the adjacent N-type polycrystalline silicon and the P-type polycrystalline silicon is larger than 1 mu m, and the N-type polycrystalline silicon and the heavily doped P-type polycrystalline silicon are connected through aluminum.

The thermocouple layer can be formed by a CMOS standard silicon deposition process such as a Low Pressure Chemical Vapor Deposition (LPCVD) method, doping the polycrystalline silicon film by an ion implantation method, and patterning the polycrystalline silicon film by processes such as induction lithography, coupled plasma etching (ICP), Reactive Ion Etching (RIE), wet etching and the like.

The insulating medium layer grows on the thermocouple layer, the material of the insulating medium layer comprises one or two of silicon oxide and silicon nitride, and the insulating medium layer can be formed by adopting the processes of Plasma Enhanced Chemical Vapor Deposition (PECVD) and the like.

The metal pattern layer is formed on the insulating medium layer and comprises an electrode and a lead wire, the p-type polycrystalline silicon and the N-type polycrystalline silicon resistance block are connected to form a thermopile, the middle of the thermopile is connected with the polycrystalline silicon and the like through an insulating layer by photoetching and other processes, the cold end and the hot end of the thermopile layer are connected with the outside at the metal pattern layer by an aluminum electrode, the metal layer is made of metal with good conductivity and comprises but not limited to one or more of aluminum, silver, gold, titanium, tungsten and platinum, and the metal pattern layer can be formed by magnetron sputtering, electron beam evaporation, a stripping process or an electroplating process and is formed by photoetching and other processes in a patterning mode.

The infrared absorption layer grows on the upper surface of the hot end of the thermopile and is formed by depositing metal nano materials. Compared to the case where only the composite film layer is used as the absorption layer, nanoparticles such as gold nanorods may have a high absorption rate for infrared light by the surface plasmon resonance effect, and may dissipate their crystal lattice heat to the conductive layer within several tens of picoseconds. Thus having better absorption and faster thermal response time, the layer is composed of a controlled density of aligned or randomly oriented nanoparticle layers that can be deposited by spraying, printing, spin coating, etc., and the alignment of the nanoparticles can be controlled by microfluidics, etc.

The high-reflection heat dissipation layer grows on the upper surface of the cold end of the thermoelectric stack layer, and the high-reflection heat dissipation layer can be composed of a single-layer metal or a single-layer metal and a protective film, or can be a metal dielectric film system high-reflection layer formed by growing a plurality of dielectric films on a metal film. Metals having suitable infrared reflectivity may be used as the infrared reflector, preferably, these metal materials include, but are not limited to, aluminum, gold, or gold-chromium alloy, etc., the gold material is stable in property and does not react with alkaline solution, thereby simplifying the subsequent process, while aluminum material has better process compatibility with CMOS, the metal layer in the highly reflective heat dissipation layer can reflect infrared radiation on one hand and has good heat conduction and heat dissipation effects on the other hand, and each layer of the highly reflective heat dissipation layer can be manufactured by using processes of evaporation film formation, deposition film formation, photolithography and the like of a semiconductor integrated circuit.

The bottom of the detection pixel is provided with a groove to form a heat insulation cavity, the heat insulation cavity 208 penetrates through the silicon substrate 201 to expose part of the composite dielectric film 202 to form a suspended film sensitive structure, the composite film layer and the thermopile layer are locally positioned in the heat insulation cavity, the heat insulation cavity can be obtained by forming a release window on the back surface of the silicon substrate 201, etching and releasing are carried out on the silicon substrate 201 from the back surface through the release window, and the release can be carried out by adopting dry etching such as Deep Reactive Ion Etching (DRIE) or the like or processes such as anisotropic wet etching, isotropic wet etching and the like.

Preferably, the single crystal silicon is a double polished single crystal silicon wafer, in one embodiment, the thickness is 400 μm and the crystal orientation is <100 >.

Preferably, the composite dielectric film 202 is formed by compounding a single layer or multiple layers of low-stress silicon oxide and silicon nitride, and the thickness can be l-10 μm. In one embodiment, the composite dielectric film 202 is formed by laminating a low stress silicon oxide/silicon nitride double-layer film with a thickness of 3 μm.

Preferably, the infrared absorption layer is deposited by using a metal nano material, and in one embodiment, the thickness of the layer is between 50nm and 1 μm.

Preferably, in one embodiment, the thickness of the heat sink layer is 70-100nm, and the thickness of the metal reflective layer in this range can block incident infrared radiation

Preferably, the material of the insulating dielectric layer 204 includes one or two of silicon oxide and silicon nitride, and in one embodiment, the insulating dielectric layer 204 is silicon oxide with a thickness of 0.1 μm.

Preferably, in an embodiment, the metal layer 205 is made of aluminum.

Preferably, the insulating cavity 208 may have a rectangular cross-section.

It should be noted that the P-type polysilicon resistor block 203-1 and the N-type polysilicon resistor block 203-2 are connected by metal leads to form thermocouples, the thermocouples are connected in series to form a thermopile structure, the number of the polysilicon thermocouples is at least 1, in one embodiment, the number of the thermocouples is 2 or 16, the shapes of the thermocouples can be adjusted as needed, and fig. 2 and 3 respectively show two types of thermopile sensors with different numbers and shapes of thermocouples provided in this embodiment.

The nano particles can cause the scattering and absorption of specific wavelength light in visible and near infrared bands through the surface plasmon resonance effect. Therefore, the infrared radiation can be sensitively detected by the low photo-thermal energy loss and the extremely strong field enhancement effect in the near infrared band, and the area and the thickness of the thermocouple layer can be reduced due to the high infrared absorption rate of the nano material, so that the aims of improving the thermal response speed, reducing the cost and the like are fulfilled.

The integration of the thermopile array and the readout circuit unit, etc. are prior art and are not described herein.

In one embodiment of the present application, the memory chip is an Electrically Erasable Programmable Read Only Memory (EEPROM). In one application example, the external interface adopts an I2C digital interface.

In one embodiment of the present application, the lenses employed are silicon lenses.

In one embodiment of the present application, the lens employed is a germanium lens.

The structure and the field angle of the infrared lens can be adjusted according to needs, in an application example, the field angle of the infrared lens is 6 DEG x 6 DEG, in an application example, the field angle of the infrared lens is 110 DEG x 110 DEG, and in an application example, the field angle of the infrared lens is 270 DEG x 270 deg.

Under the substrate of the sensing chip, a polished metal sheet is added between the substrate and the packaging base to reflect infrared rays passing through gaps and the like, so that the infrared ray absorption rate is improved, and heat generated in other areas of the substrate can be rapidly led out.

The surface of the metal reflector adopts a polished metal reflector which is polished into a mirror surface, so that infrared rays are reflected to the hot end in front better.

The metal reflecting sheet can be made of a single material, and can be in a structure that one metal material is plated with another metal material.

In one embodiment of the present application, the reflective sheet is made of aluminum.

In one embodiment of the present application, the reflective sheet is made of a copper sheet plated with an aluminum reflective film.

In one embodiment of the present application, the reflector is processed to form a concave lens shape, the center of the concave lens is aligned with the center region of the hot end of the sensing pixel, and the focal length of the concave lens is set to focus the infrared light on the center region of the hot end of the sensing pixel.

In one embodiment of the present application, the retroreflective sheeting is processed to form a planar shape, which is a type of sheeting that requires less alignment for packaging.

Other packaging, connection and other technical details are adopted by the general prior art in the field and are not described herein.

In summary, the present application provides an infrared sensor, which includes an infrared lens, a package housing, a substrate, a sensing chip, a memory chip, a reflective metal sheet, a pin, and the like, wherein the sensing chip includes an sensing array and a signal processor, the sensing array includes a sensing portion and a reference control portion, the reference control portion can detect an ambient temperature for signal comparison processing, and the memory chip is used for storing calibration and conversion between an ambient temperature coefficient, a digital voltage signal output by an analog-to-digital voltage conversion chip, and a set output standard digital voltage signal according to a pre-stored rule. The infrared detector sensing array is manufactured by adopting a CMOS standard process and an MEMS technology, has the advantages of small volume, high response speed and the like, increases the temperature difference between the hot end and the cold end of the thermopile, is favorable for realizing accurate measurement of a thermal signal, and can reduce the area and the thickness of a thermocouple layer due to the high infrared absorption rate of a nano material so as to achieve the purposes of improving the thermal response speed, reducing the cost and the like. The lens, the thermopile sensing chip, the memory chip and the like are integrally packaged on the substrate, wherein under the substrate of the sensing chip, a polished metal sheet is added between the substrate and the packaging base and used for reflecting infrared rays penetrating through gaps and other positions, the infrared absorption rate is improved, heat generated in other areas of the substrate can be rapidly led out, the absorption efficiency of an infrared absorption layer in a hot area is improved, when the chip silicon substrate (cold area) is irradiated by infrared rays to generate heat, the heat can be rapidly led out to the areas of the packaging base and the like by the metal sheet with excellent heat conductivity, the temperature difference of the cold area and the hot area is improved, the signal-to-noise ratio is improved, the thermopile performance is improved, the reliability of a device is improved, and the lens, the thermopile sensing chip, the memory chip and the like have the advantages of easiness in use and high cost performance.

The preferred embodiments of the present application disclosed above are intended only to aid in the explanation of the application. The preferred embodiments are not exhaustive and do not limit the specific implementations of the application. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the application and the practical application, to thereby enable others skilled in the art to best understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. An infrared sensor is characterized by comprising an infrared lens, a packaging shell, a substrate, a sensing chip, a storage chip, a polished metal sheet, pins and the like, wherein the sensing chip comprises a sensing array and a signal processing circuit, the sensing array comprises a sensing part and a signal conversion and control part, the sensing part converts optical signals into electric signals related to temperature and can detect ambient temperature for signal comparison processing, the sensing part adopts a thermopile chip using a nano material as an absorption layer, the storage chip is used for storing an ambient temperature coefficient calculated according to a pre-stored rule, and after the signal processing and control part processes the electric signals, the digital voltage signals output by an analog-to-digital voltage conversion module and set output standard digital voltage signals are calibrated and converted.

2. A detection chip of a thermopile infrared detector as claimed in claim 1, wherein the sensing pixels of the sensing array of the chip comprise single crystal silicon, a composite film layer, a thermocouple layer, an insulating medium layer, a metal pattern layer, an infrared absorption layer, a high reflection heat dissipation layer and the like, the composite film layer is grown on the upper surface of the single crystal silicon layer, the thermocouple layer is grown on the composite film layer, the thermocouple layer is composed of thermocouples connected in series, the thermocouple material is formed by connecting heavily doped N-type polycrystalline silicon and heavily doped P-type polycrystalline silicon in a pair mode, the N-type polycrystalline silicon and the heavily doped P-type polycrystalline silicon are connected through aluminum in the middle, the insulating medium layer is grown on the thermocouple layer, the metal pattern layer is formed on the insulating medium layer and comprises electrodes, leads and the like so as to connect the blocks of the P-type polycrystalline silicon and the N-type polycrystalline silicon to form the thermopile, the middle of the thermoelectric module is connected with polycrystalline silicon and the like through an insulating layer by photoetching and other processes, the cold end and the hot end of the thermopile layer are connected with the outside at the metal pattern layer by an aluminum electrode, the infrared absorption layer grows on the upper surface of the hot end of the thermopile, the high-reflection heat dissipation layer grows on the upper surface of the cold end of the thermopile layer, a groove is formed at the bottom of the infrared detector to form a heat insulation cavity, the heat insulation cavity penetrates through monocrystalline silicon to expose the composite film layer, and the local part of the thermopile thermocouple layer is positioned in the heat insulation cavity.

3. The detection chip of the thermopile infrared detector recited in claim 1, wherein the high absorption rate infrared absorption layer is added to the infrared radiation receiving area at the hot end of the sensing pixel of said thermopile, and the high reflection heat dissipation layer is added at the cold end, so as to increase the temperature difference between the cold end and the hot end of the thermocouple, thereby increasing the sensing voltage output and improving the sensitivity of the device.

4. The infrared sensor as claimed in claim 1, wherein said lens, said thermopile sensing chip and said memory chip are integrally packaged on a base plate, wherein a polished metal plate is interposed between a substrate of said sensing chip and a package base under said substrate.