CN211954453U

CN211954453U - Thermopile sensor structure

Info

Publication number: CN211954453U
Application number: CN202020772165.1U
Authority: CN
Inventors: 孙其梁; 徐乃涛; 程进; 李宋泽
Original assignee: Wuxi Micro Vision Sensor Technology Co ltd
Current assignee: Wuxi Micro Vision Sensor Technology Co ltd
Priority date: 2020-05-11
Filing date: 2020-05-11
Publication date: 2020-11-17
Anticipated expiration: 2030-05-11

Abstract

The utility model discloses a thermopile sensor structure relates to sensor technical field, including thermopile sensor and polymer lens, polymer lens pass through the coating film mode and deposit on the top of thermopile sensor, and polymer lens are convex lens, and outside infrared radiation light passes polymer lens perpendicularly, and polymer lens are used for realizing outside infrared radiation light and assemble on the thermopile sensor to the infrared radiant energy that makes unit area's infrared absorbing layer receive increases, and thermopile sensor output voltage increases, and then has promoted whole integrated circuit's chip response rate.

Description

Thermopile sensor structure

Technical Field

The utility model belongs to the technical field of the sensor technique and specifically relates to a thermopile sensor structure.

Background

The thermopile infrared sensor is widely applied to the fields of ear thermometers, radiation thermometers, electric ovens, food temperature detection and the like, and can realize the non-contact temperature detection of a detected object. The conventional thermopile sensor mainly comprises a substrate, thermocouple strip pairs and conductive electrodes, but the conventional thermopile sensor has the problem of low chip response rate, the conventional manner for improving the chip response rate mainly aims at adjusting the internal structure thereof, for example, the arrangement manner of the thermocouple strip pairs on the substrate is changed, the size of the thermocouple strips is increased, and the like, but the internal structure is inconvenient to adjust due to the limitation of the packaging size of the substrate and the thermopile sensor, and the thermoelectric material is added on the substrate with the conventional size, so that the cost is high, the process is complex, and the production and processing are difficult.

SUMMERY OF THE UTILITY MODEL

The present inventors have addressed the above-mentioned problems and needs in the art with a thermopile sensor structure. This structure has realized that outside infrared radiation light assembles on the thermopile sensor through the top deposit polymer lens at the thermopile sensor, and the design is simple reasonable, can improve chip response rate greatly.

The technical scheme of the utility model as follows:

the utility model provides a thermopile sensor structure, includes thermopile sensor and polymer lens, and the polymer lens passes through the coating film mode and deposits in the top of thermopile sensor, and the polymer lens is convex lens, and outside infrared radiation light passes the polymer lens perpendicularly, and the polymer lens is used for realizing that outside infrared radiation light assembles on the thermopile sensor.

The thermopile sensor comprises a substrate, a polymer lens is deposited on the top end of the substrate, a cavity is formed in the middle of the substrate, an infrared absorption layer, a thermopile layer and conductive electrodes are arranged at the bottom of the substrate from top to bottom, the conductive electrodes comprise at least two conductive electrodes which are distributed on two sides of the bottom of the infrared absorption layer, the thermopile layer is arranged between the two conductive electrodes, the thermopile layer comprises a plurality of thermocouple pairs, each thermocouple pair comprises at least two thermocouple strips which are distributed up and down, the thermocouple strips are isolated by isolation layers, through holes are respectively formed in each isolation layer, the thermocouple strips are electrically connected through the through holes, a protective layer covers the periphery of the thermocouple strips, release holes are formed in the middle of the bottom end of the substrate, the release holes comprise at least two release holes, and the release holes respectively penetrate through the protective layer and the infrared absorption layer and are communicated with the cavity, and the bottom of the conductive electrode is provided with a conductive connecting block, and the conductive connecting block is connected with the control circuit as the output end of the thermopile sensor.

The control circuit is a signal processing circuit, the thermopile sensor is electrically connected with the signal processing circuit, the signal processing circuit comprises a second conductive electrode and a second conductive connecting block, the second conductive connecting block is connected with the output end of an internal circuit system of the signal processing circuit through the second conductive electrode, the second conductive electrode is correspondingly in contact connection with the second conductive connecting block, the inner end face of the second conductive connecting block is an arc-shaped groove, the conductive connecting block is embedded in the groove of the second conductive connecting block, and the shape of the conductive connecting block is consistent with that of the inner end face of the groove of the second conductive connecting block.

The utility model has the beneficial technical effects that:

set up polymer lens on thermopile sensor's top, outside infrared radiation light passes polymer lens perpendicularly, realizes gathering of infrared radiation light through polymer lens to the infrared radiation energy that makes unit area's infrared absorbing layer receive increases, and thermopile sensor output voltage increases, and then has promoted whole integrated circuit's chip response rate.

Drawings

FIG. 1 is a cross-sectional view of a thermopile sensor structure provided in one embodiment of the present application.

Fig. 2 is a cross-sectional view of an electrical connection between a thermopile sensor and a signal processing circuit according to the second embodiment of the present application.

Fig. 3 is a schematic diagram of an optical path structure of external infrared radiation light passing through a polymer lens to an infrared absorption layer in an ideal case provided by the present application.

Detailed Description

The following describes the embodiments of the present invention with reference to the accompanying drawings.

The first embodiment is as follows:

a thermopile sensor structure is shown in fig. 1, and includes a thermopile sensor 1 and a polymer lens 2, where the polymer lens 2 is deposited on the top end of the thermopile sensor 1 by a coating method, and the polymer lens 2 is a convex lens, and optionally, the polymer lens 2 of this embodiment is a plano-convex lens, where the planar side is connected with the top end of the thermopile sensor 1. The external infrared radiation light 3 vertically passes through the polymer lens 2, the external infrared radiation light 3 is converged to an infrared absorption region at the center of the bottom of the cavity, namely the infrared absorption layer 12, the polymer lens 2 is made of polydimethylsiloxane PDMS or other high-refractive-index optical polymer materials, and the polymer lens is prepared through a reflux process.

The thermopile sensor 1 comprises a substrate 11, a polymer lens 2 is deposited on the top end of the substrate 11, a cavity 19 is formed in the middle of the substrate 11, an infrared absorption layer 12 and a thermopile layer are sequentially arranged at the bottom of the substrate 11 from top to bottom, conductive electrodes 13 are arranged at the bottom end of the infrared absorption layer 12 and on two sides of the thermopile layer, the number of the conductive electrodes 13 is two, the thermopile layer comprises thermocouple pairs, each thermocouple pair comprises two thermocouple strips 14 which are arranged up and down, the two thermocouple strips 14 are isolated by an isolation layer 15, each isolation layer 15 is respectively provided with a through hole 16, the two thermocouple strips 14 are electrically connected through the through holes 16, the periphery of each thermocouple strip 14 is covered with a protective layer 17, a release hole 18 is formed in the middle of the bottom end of the substrate 11, the two release holes 18 respectively penetrate through the protective layer 17 and the infrared absorption layer 12 to be communicated with the cavity 19 in sequence, a conductive connection, the conductive connection block 10 is connected to the control circuit as an output of the thermopile sensor 1.

In the present embodiment, the substrate 11 is: bulk silicon, the infrared absorbing layer 12 is: the structure comprises silicon nitride, a protective layer 17 made of silicon oxide, thermocouple strips 14 made of polysilicon or metal or a combination of two different materials of polysilicon and polysilicon, and polymer lenses 2 and a substrate 11, the substrate 11 and an infrared absorption layer 12, the infrared absorption layer 12 and a thermoelectric stack layer, and the thermoelectric stack layer and the protective layer 17 are connected mainly through a coating process.

Example two:

a thermopile sensor structure is shown in fig. 1 and fig. 2, and includes a thermopile sensor 1 and a polymer lens 2, the polymer lens 2 is deposited on the top end of the thermopile sensor 1 by a coating method, the polymer lens 2 is a convex lens, optionally, the polymer lens 2 of this embodiment is a plano-convex lens, wherein the planar side of the plano-convex lens is connected with the top end of the thermopile sensor 1. The external infrared radiation light 3 vertically passes through the polymer lens 2, the external infrared radiation light 3 is converged to an infrared absorption region at the center of the bottom of the cavity, namely the infrared absorption layer 12, the polymer lens 2 is made of polydimethylsiloxane PDMS or other high-refractive-index optical polymer materials, and the polymer lens is prepared through a reflux process.

In the present embodiment, the substrate 11 is: bulk silicon, the infrared absorbing layer 12 is: the thermocouple sensor comprises silicon nitride, a protective layer 17 made of silicon oxide, a thermocouple strip 14 made of polysilicon or metal or a combination of two different materials of polysilicon and polysilicon, a polymer lens 2 and a substrate 11, the substrate 11 and an infrared absorption layer 12, the infrared absorption layer 12 and a thermopile layer, and the thermopile layer and the protective layer 17 are connected through a coating process, optionally, a control circuit is a signal processing circuit 4, and the thermopile sensor 1 is electrically connected with the signal processing circuit 4. The signal processing circuit employs an existing conventional circuit, and therefore, its internal circuit configuration is not described in detail.

As shown in fig. 2, the signal processing circuit 4 is connected to the conductive connection block 10 on the thermopile sensor 1 through a second conductive connection block 42, the thermopile sensor 1 is stacked above the signal processing circuit 4, the signal processing circuit 4 includes a second conductive electrode 41, the second conductive connection block 42 is connected to the output end of the internal circuit system of the signal processing circuit 4 through the second conductive electrode 41, the second conductive electrode 41 is correspondingly connected to the second conductive connection block 42 in a contact manner, the inner end surface of the second conductive connection block 42 is an arc-shaped groove, the conductive connection block 10 is embedded in the groove of the second conductive connection block 42, the shape of the conductive connection block 10 is the same as that of the inner end surface of the groove of the second conductive connection block 42, the contact area between the conductive connection block 10 and the second conductive connection block 42 is increased, and the conductive connection block 10 and the second conductive connection block 42 can be stably connected, and the problems of virtual connection and the like are prevented.

The specific working principle of the thermopile sensor structure is as follows:

the external infrared radiation 3 is converged by the polymer lens 2 and transmitted to the infrared absorption layer 12, as shown in fig. 3, the optical path of the infrared absorption layer 12 is related to the thickness and width of the polymer lens 2, and ideally, when the thickness t of the polymer lens 2 is t1, the formula is satisfied:

when the thickness t of the polymer lens 2 is t2, the formula is satisfied:

wherein f is₁、f₂The optical path transmission distances of the polymer lens 2 under different thicknesses t1 and t2 are respectively, D is the width of the polymer lens, D is the width of the infrared absorption layer 12 below the cavity, and h is the distance from the polymer lens 2 to the bottomThe vertical distance of the region of the square infrared absorption layer 12, n is the refractive index of the polymer lens 2, and R is the radius of curvature of the polymer lens 2.

Specifically, the calculation formula of the curvature radius R of the polymer lens is as follows:

wherein: t is the polymer lens thickness.

It can be seen from the above formula and the optical path transmission in fig. 3 that the arrangement of the polymer lens 2 affects the transmission effect of the external infrared radiation light 3, and the values of the thickness, the width and other parameters of the polymer lens 2 are reasonably set, so that the convergence of the external infrared radiation light 3 can be realized, and the infrared radiation energy received by the infrared absorption layer 12 per unit area is increased, according to the working principle of the thermopile sensor 1, the more the infrared radiation energy absorbed by the infrared absorption layer 12 is, the higher the voltage output by the thermopile sensor 1 is, and the higher the chip response rate of the whole thermopile sensor 1 is.

What has been described above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is to be understood that other modifications and variations directly derivable or suggested by those skilled in the art without departing from the spirit and scope of the present invention are to be considered as included within the scope of the present invention.

Claims

1. A thermopile sensor structure is characterized by comprising a thermopile sensor and a polymer lens, wherein the polymer lens is deposited at the top end of the thermopile sensor in a coating mode, the polymer lens is a convex lens, external infrared radiation light vertically penetrates through the polymer lens, and the polymer lens is used for realizing the convergence of the external infrared radiation light on the thermopile sensor.

2. The thermopile sensor structure of claim 1, wherein the thermopile sensor comprises a substrate, the polymer lens is deposited on the top of the substrate, a cavity is formed in the middle of the substrate, an infrared absorption layer, a thermopile layer, and conductive electrodes are disposed at the bottom of the substrate, the infrared absorption layer and the thermopile layer are sequentially disposed from top to bottom, the conductive electrodes comprise at least two thermocouple strips disposed on both sides of the bottom of the infrared absorption layer, the thermopile layer is disposed between the two conductive electrodes, the thermopile layer comprises a plurality of thermocouple pairs, each thermocouple pair comprises at least two thermocouple strips disposed vertically, each thermocouple strip is isolated by an isolation layer, each isolation layer is respectively provided with a through hole, each thermocouple strip is electrically connected by the through hole, and a protective layer covers the periphery of each thermocouple strip, the bottom middle part of the substrate is provided with at least two release holes, each release hole sequentially penetrates through the protective layer and the infrared absorption layer to be communicated with the cavity, the bottom of the conductive electrode is provided with a conductive connecting block, and the conductive connecting block is used as the output end of the thermopile sensor and is connected with a control circuit.

3. The thermopile sensor structure according to claim 2, wherein the control circuit is a signal processing circuit, the thermopile sensor is electrically connected to the signal processing circuit, the signal processing circuit includes a second conductive electrode and a second conductive connection block, the second conductive connection block is connected to an output terminal of an internal circuit system of the signal processing circuit through the second conductive electrode, the second conductive electrode is correspondingly connected to the second conductive connection block in a contact manner, an inner end surface of the second conductive connection block is an arc-shaped groove, the conductive connection block is embedded in the groove of the second conductive connection block, and a shape of the conductive connection block is identical to a shape of the inner end surface of the groove of the second conductive connection block.