CN212963723U

CN212963723U - Digital infrared temperature sensor

Info

Publication number: CN212963723U
Application number: CN202021792986.8U
Authority: CN
Inventors: 李言杰
Original assignee: Nanjing University of Information Science and Technology
Current assignee: Nanjing University of Information Science and Technology
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2021-04-13
Anticipated expiration: 2030-08-25

Abstract

The utility model belongs to a digital infrared temperature sensor, which comprises a ceramic packaging shell, a thermopile chip, an ASIC circuit module, an NTC thermistor, a packaging plate, an external interface and an infrared lens, wherein the infrared lens is embedded at the top of the ceramic packaging shell, and the packaging plate is positioned at the bottom of the ceramic packaging shell; the infrared lens, the ceramic packaging shell and the packaging plate form a sealed cavity, the ceramic packaging shell is provided with a separation ceramic plate to divide the cavity into two parts, and the ASIC circuit module and the NTC thermistor are utilized to obtain the digital infrared temperature sensor with a large view field, small volume, high precision, good heat insulation performance and strong anti-interference capability.

Description

Digital infrared temperature sensor

Technical Field

The utility model belongs to the technical field of infrared temperature sensor, especially adopt infrared lens and ceramic package's the digital infrared temperature sensor who contains two cavities.

Background

All objects higher than absolute zero degree in nature can radiate energy outwards, the size of the radiation energy of the object and the wavelength distribution of radiation waves are closely related to the surface temperature of the object, and the higher the temperature of the object is, the stronger the infrared radiation capability is, so that the infrared temperature measurement has a wide application range. The infrared temperature measurement technology plays an important role in the aspects of production process monitoring, product quality control and monitoring, equipment online fault diagnosis, energy conservation and the like. Compared with a contact temperature measurement method, the infrared temperature measurement method has the advantages of fast response, non-contact, safety, long service life and the like. In recent years, in order to avoid the pollution of mercury thermometers to the environment, non-contact infrared human body thermometers are also developed rapidly, the performance is improved continuously, the functions are enhanced continuously, the variety is increased continuously, and the application range is expanded continuously. The infrared temperature sensor can convert infrared radiation energy into an electric signal and is a core component of an infrared temperature measurement technology.

At present, an infrared temperature sensor usually uses an infrared band-pass or long-pass filter as an infrared lens, and the filter can filter out interference light outside an infrared band emitted by an object to be detected and an environmental object, and simultaneously infrared light of the detection band can penetrate through and radiate to a sensing area of a thermopile. However, the infrared filter cannot independently adjust the field angle of the sensor, and needs to cooperate with structures such as a window and a thermopile chip to complete the adjustment of the field angle of the sensor. In addition, the sensor provided with the filter is short in detection distance and small in field angle.

Nowadays, the thermopile infrared sensor mainly uses plastic packaging, and the plastic packaging has the advantages of low price, small weight and size and the like, but the thermopile infrared sensor is greatly influenced by the environment due to the defects of mismatched thermal expansion coefficient, low thermal conductivity, poor corrosion resistance and the like.

The infrared temperature sensor has the following defects that (1) the infrared filter does not have a focusing function, cannot directly adjust the field angle of the sensor, and needs to cooperate with structures such as a window to complete the adjustment of the field angle. (2) The light wave penetrating through the infrared filter is dispersed, the required thermopile sensing area is relatively large, and the further miniaturization of the thermopile chip is difficult. (3) The detection distance is limited, and the detection field of view is narrow. (4) The environmental impact on the thermopile infrared sensor is large due to the defects of mismatched coefficient of thermal expansion, low thermal conductivity, poor corrosion resistance and the like of the plastic package.

Disclosure of Invention

In view of above defect, the utility model provides an infrared temperature sensor of digital based on infrared lens and ceramic package, assemble the light wave through infrared lens, divide into two upper and lower cavities through keeping apart the ceramic plate through inside, use ceramic package shell and pour into inert gas into to its evacuation and make the heat-proof quality more excellent, use NTC thermistor to compensate thermopile cold junction temperature simultaneously, utilize ASIC circuit module to make output signal be digital signal, thereby obtain big visual field, small, high precision, the heat-proof quality is good, digital infrared temperature sensor that the interference killing feature is strong.

In order to realize the technical purpose, the utility model adopts the following technical scheme:

a digital infrared temperature sensor comprises a ceramic packaging shell, a thermopile chip, an ASIC circuit module, an NTC thermistor, a packaging plate, an external interface and an infrared lens, wherein the infrared lens is embedded at the top of the ceramic packaging shell, and the packaging plate is positioned on the ceramic packaging shell; the infrared lens, the ceramic packaging shell and the packaging plate form a sealed cavity, and the ceramic packaging shell is provided with an isolating ceramic plate to divide the cavity into two parts, the thermopile chip is positioned in the upper cavity, and the ASIC circuit module and the NTC thermistor are horizontally arranged, positioned below the thermopile chip and positioned in the lower cavity; the ceramic packaging shell is not in direct contact with the thermopile chip, the ASIC circuit module and the NTC thermistor.

Furthermore, vacuum holes are respectively formed in the ceramic packaging shell and the isolation ceramic plate, and inert gas is injected after the interior of the sensor is vacuumized through the vacuum holes.

Furthermore, welding spots are arranged on the upper and lower parts of the isolation ceramic plate, and the bottom of the thermopile chip is welded with the ceramic isolation plate; the ASIC circuit module and the NTC thermistor are both welded with the isolating ceramic plate at the top.

Furthermore, a window part for accommodating the infrared lens is arranged at the top of the ceramic packaging shell, and the window part ensures that the focus of the infrared lens is always positioned in the center of the thermopile chip; the bottom of the infrared lens is contacted with the bottom surface of the window part, a transparent sealing material is filled in a gap between the top of the infrared lens and the window part, and the infrared lens completely covers the window part.

Furthermore, a sealing cover made of soft materials is arranged at the vacuum hole of the ceramic packaging shell, and the vacuum hole is tightly matched.

Furthermore, the packaging plate is mounted at the bottom of the ceramic packaging shell by using an adhesive.

Furthermore, the edge of the infrared lens is provided with an embedding slot for embedding and clamping the window.

Advantageous effects

Infrared temperature measurement digital sensor based on infrared lens and ceramic package assembles the light wave through infrared lens, and use ceramic package and pour into inert gas into to its evacuation and make the heat-proof quality more excellent, utilize to keep apart the ceramic plate and separate the cavity, make the sensor miniaturation, use NTC thermistor to compensate thermopile cold junction temperature simultaneously, utilize ASIC circuit module to make output signal be digital signal, thereby high sensitivity, high accuracy, big visual field, far detection distance, but focusing function and high interference killing feature's beneficial effect has been obtained.

Drawings

FIG. 1 is a schematic cross-sectional view of a digital infrared temperature sensor based on an infrared lens and a ceramic package;

FIG. 2 is a schematic cross-sectional view of a digital infrared temperature sensor based on an infrared lens and a ceramic package;

FIG. 3 is a square infrared lens spotlight view;

description of the symbols:

1. the infrared photoelectric sensor comprises an infrared lens, 2 parts of a thermopile chip, 3 parts of an NTC thermistor, 4 parts of an ASIC circuit module, 5 parts of a packaging plate, 6 parts of a ceramic packaging shell, 7 parts of assembly welding points, 8 parts of vacuum holes, 9 parts of through hole lines, 10 parts of external interfaces, 11 parts of an isolation ceramic plate, 12 parts of a sealing cover, 13 parts of an adhesive, 14 parts of a sealing material, 15 parts of an infrared lens and 16 parts of a thermopile chip.

Detailed Description

As in fig. 1-2, preferably, the digital infrared temperature sensor based on the infrared lens and ceramic package of the present invention includes: a ceramic package housing 6, preferably an LTCC ceramic package housing, a thermopile chip 2, an infrared lens 1, a package plate 5, an NTC thermistor 3 and an ASIC circuit module 4.

The infrared lens 1 converges the light waves on the thermopile chip 2, providing a condition basis for further miniaturization of the thermopile chip 2.

Preferably, the thermopile chip 2 may be fabricated by a CMOS compatible MEMS technology, which may reduce the volume to the maximum extent and achieve high precision.

Preferably, the LTCC ceramic is used for packaging the infrared temperature measurement digital sensor based on the infrared lens and ceramic package, and the air tightness and the anti-interference capability of the sensor can be improved.

The ceramic packaging shell 6 is provided with an isolation ceramic plate 11 to divide the cavity into two parts, the thermopile chip 2 is positioned in the upper cavity, and the bottom of the thermopile chip is welded through a welding spot 7 positioned on the isolation ceramic plate 11; the ASIC circuit module 4 is positioned in the lower cavity and is connected with the thermopile chip 2 through a wire passing hole positioned on the isolating ceramic plate 11, and analog signals transmitted by the thermopile chip 2 are filtered and amplified and converted into digital signals; the NTC thermistor 3 is positioned in the lower cavity; the top of the ASIC circuit module 4 and the top of the NTC thermistor 3 are connected through a welding point 7 on the isolating ceramic plate 11, and the NTC thermistor 3 is connected with the ASIC circuit module 4 and compensates the cold end temperature of the thermopile chip 2.

Further, the ASIC circuit module 4 is connected to an external device via an external interface 10 and transmits analog signals. The readability and the easy integration of the digital infrared temperature sensor are improved by the integrated ASIC circuit module 4.

As shown in fig. 2, vacuum holes 8 are respectively formed in the ceramic package housing 6 and the isolation ceramic plate 11, the vacuum holes 8 are used as exhaust holes to perform vacuum treatment on the interior of the sensor, and then used as air guide holes to be channels for injecting inert gas, after the gas is injected, the vacuum holes 8 in the ceramic package housing are sealed by using a sealing cover 12, the sealing cover 12 is made of soft material, is in close fit with the vacuum holes 8, and ensures that the vacuum holes 8 are completely sealed by elastic deformation of the soft material. The preferred closure cap 12 is a rubber or silicone material. The application of this structure has greatly improved the heat-proof quality, has strengthened stability and interference killing feature. Preferably, the inert gas used in the present invention is argon.

As shown in fig. 1, the encapsulating plate 5 is mounted at the bottom of the ceramic encapsulating shell 6 by using an adhesive 13, and the gap between the encapsulating plate 5 and the ceramic encapsulating shell 6 is filled by using the fluidity and elasticity of the adhesive, so as to ensure the sealing effect of the cavity. Meanwhile, the adhesive 13 needs to ensure that the state does not change at the operating temperature, and preferably, the adhesive 13 is thermosol or epoxy glue.

Preferably, the material of the infrared lens 1 may be one or more of silicon, germanium, and HDPE (high density polyethylene material). The infrared lens is a spherical lens, a hemispherical lens, a plane lens and the like. Preferably, the surface of the infrared lens can also be hardened to achieve the scratch-proof effect; preferably, the infrared lens 1 is a self-focusing lens.

The shape of which can be changed according to design requirements, as shown in fig. 3, the infrared lens 15 is square.

The infrared lens comprises a ceramic packaging shell 6, wherein a window part is formed in the top of the ceramic packaging shell 6, and the position of the window part ensures that the focus of the infrared lens 1 is always positioned in the center of the thermopile chip 2. The infrared lens 1 is embedded in the window of the ceramic packaging shell 6, the bottom of the infrared lens 1 is in contact with the bottom surface of the window part, a transparent sealing material 14 is filled in a gap between the top of the infrared lens 1 and the window part, the infrared lens completely covers the window part, and preferably, the sealing material 14 is epoxy glue.

Furthermore, an embedding slot for embedding and clamping the window is formed in the edge of the infrared lens.

The external interface 10 preferably has five pins, SDA, VDD, GND, SCL, ADDR, mounted on the bottom of the ceramic package 6. The function of the SDA is the I2C data line; VDD is a power supply terminal; GND is the ground; SCL is the I2C clock line; ADDR is the LSB port of I2C.

The utility model provides a digital infrared temperature sensor based on infrared lens and ceramic package replaces infrared filter with infrared lens and has increased detection visual field and detection distance, assembles the light wave in a bit, provides the condition basis for the further miniaturization of thermopile chip. The infrared lens is embedded in the window at the top of the packaging shell, so that a closed space is formed inside the box body, and the infrared lens is superior to an infrared filter in use simplicity. In addition, the matching application of the LTCC ceramic package, the NTC thermistor and the ASIC circuit module greatly improves the anti-interference capability, readability and easy integration of the sensor.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention, and any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A digital infrared temperature sensor comprises a ceramic packaging shell, a thermopile chip, an ASIC circuit module, an NTC thermistor, a packaging plate, an external interface and an infrared lens, wherein the infrared lens is embedded at the top of the ceramic packaging shell, and the packaging plate is positioned on the ceramic packaging shell; the infrared lens, the ceramic packaging shell and the packaging plate form a sealed cavity, and the ceramic packaging shell is provided with an isolating ceramic plate to divide the cavity into two parts, the thermopile chip is positioned in the upper cavity, and the ASIC circuit module and the NTC thermistor are horizontally arranged, positioned below the thermopile chip and positioned in the lower cavity; the ceramic packaging shell is not in direct contact with the thermopile chip, the ASIC circuit module and the NTC thermistor.

2. The digital infrared temperature sensor of claim 1, wherein the ceramic package housing and the isolating ceramic plate are respectively provided with a vacuum hole, and inert gas is injected after the interior of the sensor is vacuumized through the vacuum holes.

3. The digital infrared temperature sensor according to claim 1, wherein a window portion for accommodating the infrared lens is arranged on the top of the ceramic package shell, and the window portion ensures that the focus of the infrared lens is always located at the center of the thermopile chip; the bottom of the infrared lens is contacted with the bottom surface of the window part, a transparent sealing material is filled in a gap between the top of the infrared lens and the window part, and the infrared lens completely covers the window part.

4. The digital infrared temperature sensor according to claim 1, wherein the isolating ceramic plate is provided with welding spots on the upper and lower sides, and the bottom of the thermopile chip is welded with the ceramic isolating plate; the ASIC circuit module and the NTC thermistor are both welded with the isolating ceramic plate at the top.

5. The digital infrared temperature sensor of claim 2, wherein the vacuum holes in the ceramic package are provided with a sealing cap of soft material, close fitting vacuum holes.

6. The digital infrared temperature sensor of claim 1, wherein the package board is mounted to the bottom of the ceramic package housing using an adhesive.

7. The digital infrared temperature sensor as claimed in claim 1, wherein the edge of the infrared lens is provided with a slot for inserting the window.