Paster type production method of pyroelectric sensor

Abstract

The invention discloses a surface-mounted production method of a pyroelectric sensor, and relates to the technical field of sensor manufacturing, and the surface-mounted production method comprises the following steps: manufacturing a PCB bottom plate, and carrying out the backflow installation of a pyroelectric conditioning chip; dispensing a conductive adhesive material on the PCB bottom plate, fixing the supporting column, and drying and curing; dispensing a conductive adhesive material on the top of the support column, fixing the pyroelectric crystal, and drying and curing the pyroelectric crystal; dispensing conductive silver paste on the edge of the PCB bottom plate, attaching a PCB enclosure, drying and curing; and mounting an optical filter on the PCB enclosure, pouring an adhesive around the optical filter, and drying and curing the optical filter. The pyroelectric sensor produced or manufactured by using the patch type production method has the characteristics of low cost, high reliability and excellent electromagnetic shielding performance, and the production method also has the characteristic of high process compatibility.

Description

Technical Field

[0001] This invention relates to the field of sensor manufacturing technology, specifically to a patch-type production method for pyroelectric sensors. Background Technology

[0002] Pyroelectric sensors are widely used in smart homes (such as motion-sensor lights, smart door locks, and automatic start / stop of air conditioners) and security systems (such as intrusion detectors and surveillance alarms) due to their high sensitivity to infrared radiation and low power consumption. Currently, the traditional manufacturing processes for pyroelectric sensors mainly employ two methods: one is injection molding, where the sensor body is molded into a single unit using a plastic mold; the other is encapsulation using a PCB substrate combined with a metal casing, where the metal casing provides shielding and protection, and a hermetically sealed seal is achieved through welding.

[0003] However, both processes have significant limitations: injection molding requires customized high-precision molds, resulting in high upfront costs, long development cycles, and difficulty in adapting to the needs of multi-variety, small-batch product iterations; simultaneously, plastic materials are relatively poor in terms of thermal stability, dimensional accuracy, and electromagnetic shielding performance, affecting the long-term reliability of the sensor. While metal casing offers good mechanical strength and shielding, its packaging materials are expensive, and the welding process is complex. Furthermore, traditional packaging structures often struggle to balance optical performance with environmental sealing, making them susceptible to stray light, electromagnetic interference, and moisture intrusion, leading to signal drift or device failure. Summary of the Invention

[0004] Therefore, embodiments of the present invention provide a patch manufacturing method for pyroelectric sensors, which can reduce material and mold costs, simplify the process flow, and improve product reliability.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] The first aspect of this invention provides a patch-type manufacturing method for a pyroelectric sensor, comprising:

[0007] Chip fixing; conductive adhesive is printed on the chip pads on the PCB base plate, the pyroelectric conditioning chip is mounted on the chip pads, and reflow soldering is performed to fix it;

[0008] Fix the support column; apply conductive adhesive to the preset support point position on the PCB base plate, place the support column at the preset support point position, and dry and cure;

[0009] Pyroelectric crystal fixing; apply conductive adhesive to the top of the fixed support column, attach the pyroelectric crystal to the top of the support column, and dry and cure.

[0010] Frame fixing; apply conductive adhesive to the dispensing pads on the PCB base plate, align and attach the PCB frame to the PCB base plate, and dry and cure.

[0011] Filter fixing; attach the filter to the top opening of the PCB enclosure.

[0012] Furthermore, the substrate of the PCB base plate is FR4 substrate; the pyroelectric conditioning chip is a packaged chip or a bare chip assembled by COB; the conductive adhesive is conductive silver paste or solder paste; and the support pillars are silicon crystal pillars, copper pillars, surface mount resistors or surface mount capacitors.

[0013] Furthermore, the surface mount manufacturing method also includes sealing the casing; adhesive is filled at the joint between the PCB substrate and the PCB casing, and then dried and cured.

[0014] Furthermore, the patch manufacturing method also includes filter sealing; a ring of adhesive is poured around the joint between the filter and the PCB housing, and then dried and cured.

[0015] Furthermore, the adhesive is epoxy glue, AB glue, UV glue, underfill glue, or potting compound.

[0016] Furthermore, the PCB enclosure is made of PCB substrate and manufactured through PCB drilling and through-hole metallization processes.

[0017] Furthermore, the surface mount manufacturing method also includes shell reinforcement: applying colloid into a groove on the back of the PCB substrate and drying and curing it.

[0018] A second aspect of the present invention provides another method for patch manufacturing of a pyroelectric sensor, comprising:

[0019] Frame fixing; apply conductive adhesive to the dispensing pads on the PCB base plate, align and attach the PCB frame to the PCB base plate, and dry and cure.

[0020] Chip fixing; conductive adhesive is printed on the chip pads on the PCB base plate, the pyroelectric conditioning chip is mounted on the chip pads, and reflow soldering is performed to fix it;

[0021] Fix the support column; apply conductive adhesive to the preset support point position on the PCB base plate, place the support column at the preset support point position, and dry and cure;

[0022] Pyroelectric crystal fixing; apply conductive adhesive to the top of the fixed support column, attach the pyroelectric crystal to the top of the support column, and dry and cure.

[0023] Filter fixing; attach the filter to the top opening of the PCB enclosure.

[0024] The embodiments of the present invention have the following advantages:

[0025] 1. Low cost: Relying on mature PCB processes and surface mount technology, there is no need to customize expensive metal turning molds or high-precision injection molds, which greatly reduces material procurement and initial equipment investment costs; at the same time, it simplifies the production process, reduces the additional expenses caused by process complexity, and adapts to the needs of multi-variety, small-batch product iteration.

[0026] 2. High reliability: Through multi-step dispensing and stepped curing processes, the conductivity stability of the conductive adhesive is ensured, and the structural strength of the adhesive is strengthened. At the same time, through the design of enclosure sealing and filter sealing, moisture and stray light intrusion are effectively blocked, reducing the risk of signal drift and device failure, resulting in better product consistency.

[0027] 3. Excellent electromagnetic shielding performance: The PCB enclosure is made of PCB substrate and manufactured through PCB drilling and through-hole metallization processes. A metal shielding layer is formed on the inner wall of the window (i.e., the through hole processed by PCB drilling) of the PCB enclosure, and a continuous conductive connection is formed with the PCB base plate through conductive adhesive to build a complete electromagnetic shielding cavity, which can effectively isolate external electromagnetic interference. Combined with the structural protection of the PCB enclosure, it further improves the stability of the sensor during long-term operation.

[0028] 4. Strong process compatibility: The entire production process is highly compatible with standard SMT (Surface Mount Technology) production lines, eliminating the need for additional dedicated production lines. This facilitates automated mass production, shortens production cycles, improves production efficiency, and lowers the barriers to large-scale production. Attached Figure Description

[0029] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0030] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0031] Figure 1 This is a schematic diagram of the structure of a pyroelectric sensor provided in an embodiment of the present invention.

[0032] In the diagram: 10, PCB base plate; 11, chip pad; 12, adhesive pad; 13, preset support point position; 20, pyroelectric conditioning chip; 30, support pillar; 40, pyroelectric crystal; 50, PCB enclosure; 51, copper layer; 60, filter. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a patch-type manufacturing method for a pyroelectric sensor, referencing... Figure 1 The structure shown includes the following steps:

[0036] Step S11, chip fixing. Prepare a PCB substrate 10 with pre-designed circuitry and pads; use a solder paste printer to precisely print conductive adhesive (e.g., solder paste) on the chip pads 11, then use a high-precision pick-and-place machine to mount the pyroelectric conditioning chip 20 into place, and complete the soldering in a reflow oven.

[0037] Step S12, fixing the support column. Using a dispensing machine, apply conductive adhesive (e.g., conductive silver paste) to the preset support point position 13 on the PCB base plate 10 (this position is used to fix the support column 30). After placing the support column 30 on the conductive adhesive, transfer the whole assembly to an oven and dry it continuously at 150°C for 2 hours to fix it.

[0038] Step S13: Fixing the pyroelectric crystal. Apply conductive adhesive (e.g., conductive silver paste) again to the top of the fixed support column 30, and use a pick-and-place machine to precisely place the pyroelectric crystal 40 onto the conductive adhesive; transfer the whole assembly to an oven and dry and cure at 150°C for 2 hours to ensure that there is both a reliable mechanical connection and good electrical conductivity (mainly electrical conductivity) between the pyroelectric crystal 40 and the support column 30.

[0039] Step S14, fixing the enclosure. Apply conductive adhesive (e.g., conductive silver paste) to the pre-set adhesive pads 12 along the edge of the PCB base plate 10. Align and press the PCB enclosure 50 with the pre-cut window onto the PCB base plate 10 to ensure electrical connection (mainly electrical conduction) between the base plate and the PCB enclosure 50, forming an electromagnetic shielding cavity. Transfer the entire assembly to an oven for drying at 150°C for 2 hours to cure the conductive adhesive.

[0040] To further enhance the overall mechanical strength and environmental sealing of the sensor, an adhesive (such as epoxy glue) is injected into the gap (or specially designed glue groove) where the PCB base plate 10 and the PCB housing 50 are attached; the whole unit is then transferred to an oven and dried at 150°C for 2 hours to form a robust protective layer.

[0041] The PCB enclosure is made of PCB substrate and manufactured through PCB drilling and through-hole metallization processes. Traditionally, such enclosures are made of metal or plastic; in this embodiment, a PCB enclosure is used, which is a small annular or frame-shaped structure, a few millimeters high, fixed to the main PCB board. During manufacturing, a through-hole of a specific shape (such as a square or circular opening) is drilled on a PCB board using a mechanical drill bit or laser. This hole will become the "observation window" of the sensor. On the inner wall of the drilled hole, a conductive copper layer 51 is formed by chemical copper plating and electroplating. This is a common process for connecting different layers of circuits in multilayer boards (such as connecting the top and bottom layers), but now this technology is "creatively" used to create a shielding cavity: the hole with metallized sidewalls is used as a vertically standing conductive frame (i.e., the sidewall of the "enclosure"), and then this structure is cut off from the whole board and then upside down and attached to the main PCB board like a sleeve, forming a "cavity" surrounded by conductive walls, i.e., the PCB enclosure. Its advantages include high precision (PCB technology can achieve micron-level precision, ensuring optical alignment), conductivity (metallized sidewalls can be grounded, providing electromagnetic shielding), ease of automated production (compatible with existing PCB production lines, suitable for mass production), low cost (no need for additional molds or the purchase of metal / ceramic housings), and miniaturization (can achieve very thin and compact structures).

[0042] Step S15, filter fixing. Use a pick-and-place machine to mount the filter 60 onto the window of the PCB housing 50.

[0043] To ensure the airtightness of the filter 60 and prevent dust and moisture from entering, a ring of adhesive (such as epoxy glue) is poured around the seam between it and the PCB housing 50, and then it is dried and cured at 150°C for 2 hours.

[0044] In this embodiment, the substrate of the PCB base plate is preferably FR4 substrate, but other printed circuit board substrates may also be selected.

[0045] In this embodiment, the pyroelectric conditioning chip (also known as the pyroelectric signal conditioning chip) is a packaged chip or a bare chip assembled by COB, or it can be simplified to not having a chip attached.

[0046] In this embodiment, the conductive adhesive is preferably conductive silver paste or solder paste, but other conductive and curable adhesives may also be selected. Generally, the same type of conductive silver paste is used in each step to achieve the dual functions of mechanical fixing and electrical connection.

[0047] In this embodiment, the support pillar is preferably a silicon crystal pillar, but copper blocks, surface mount resistors, surface mount capacitors, and other conductive materials that can be mounted using SMT or die bond methods can also be selected. Copper blocks can be processed into small columnar structures, possessing good electrical and thermal conductivity. They can be used as support pillars and provide electrical connections through dispensing and curing. Surface mount resistors or capacitors are standard SMT components, consisting of rectangular ceramic bodies with metal terminals. Their advantages include standardized dimensions, ease of automated mounting (SMT equipment can directly grasp and place them), and fixation via reflow soldering or adhesive curing. Support pillars are not limited to silicon pillars; any material or component that can be mounted using SMT or die bond processes, possesses sufficient mechanical strength, and is conductive can be considered as a support pillar. This provides greater flexibility to the manufacturing process, especially facilitating compatibility with existing SMT production lines and improving production efficiency.

[0048] In this embodiment, the adhesive is preferably epoxy glue, but AB glue, UV glue, underfill glue or potting compound can also be selected.

[0049] In addition, to enhance structural strength (or to enhance the strength of the casing), adhesive is applied to the groove on the back of the PCB substrate. After curing or drying, the structural strength is increased.

[0050] Example 2

[0051] This embodiment provides another method for surface-mount manufacturing of pyroelectric sensors, referencing... Figure 1 The structure shown includes the following steps:

[0052] Step S21, fixing the enclosure. Apply conductive adhesive (e.g., conductive silver paste) to the pre-set adhesive pads 12 along the edge of the PCB base plate 10. Align and press the PCB enclosure 50 with the pre-cut window onto the PCB base plate 10 to ensure electrical connection (mainly electrical conduction) between the base plate and the PCB enclosure 50, forming an electromagnetic shielding cavity. Transfer the entire assembly to an oven for drying at 150°C for 2 hours to cure the conductive adhesive.

[0053] To further enhance the overall mechanical strength and environmental sealing of the sensor, an adhesive (such as epoxy glue) is injected into the gap (or specially designed glue groove) where the PCB base plate 10 and the PCB housing 50 are attached; the whole unit is then transferred to an oven and dried at 150°C for 2 hours to form a robust protective layer.

[0054] The PCB enclosure is made of PCB substrate and manufactured through PCB drilling and through-hole metallization processes. Traditionally, such enclosures may be made of metal or plastic; in this embodiment, a PCB enclosure is used, which is a small annular or frame-shaped structure, a few millimeters high, fixed to the main PCB board. During manufacturing, a through-hole of a specific shape (such as a square or circular opening) is drilled on a PCB board using a mechanical drill bit or laser. This hole will become the "observation window" of the sensor. On the inner wall of the drilled hole, a conductive copper layer is applied to the sidewall of the hole through chemical copper plating and electroplating. This is originally a common process for connecting different layers of circuits in multilayer boards (such as connecting the top and bottom layers), but now this technology is "creatively" used to create a shielding cavity: the hole with metallized sidewalls is used as a vertically standing conductive frame (i.e., the sidewall of the "enclosure"), and then this structure is cut from the whole board and then upside down and attached to the main PCB board like a sleeve, forming a "cavity" surrounded by conductive walls, i.e., the PCB enclosure. Its advantages include high precision (PCB technology can achieve micron-level precision, ensuring optical alignment), conductivity (metallized sidewalls can be grounded, providing electromagnetic shielding), ease of automated production (compatible with existing PCB production lines, suitable for mass production), low cost (no need for additional molds or the purchase of metal / ceramic housings), and miniaturization (can achieve very thin and compact structures).

[0055] Step S22, chip fixing. Prepare a PCB substrate 10 with pre-designed circuitry and pads; use a solder paste printer to precisely print conductive adhesive (e.g., solder paste) on the chip pads 11, then use a high-precision pick-and-place machine to mount the pyroelectric conditioning chip 20 into place, and complete the soldering in a reflow oven.

[0056] Step S23, fixing the support column. Using a dispensing machine, apply conductive adhesive (e.g., conductive silver paste) to the preset support point position on the PCB base plate 10 (this position is used to fix the support column 30). After placing the support column 30 on the conductive adhesive, transfer the whole assembly to an oven and dry it continuously at 150°C for 2 hours to fix it.

[0057] Step S24: Fixing the pyroelectric crystal. Apply conductive adhesive (e.g., conductive silver paste) again to the top of the fixed support post 30, and use a pick-and-place machine to precisely place the pyroelectric crystal 40 onto the conductive adhesive; transfer the whole assembly to an oven and dry and cure at 150°C for 2 hours to ensure that there is both a reliable mechanical connection and good electrical conductivity (mainly electrical conductivity) between the pyroelectric crystal 40 and the support post 30.

[0058] Step S25, filter fixing. Use a pick-and-place machine to mount the filter 60 onto the window of the PCB housing 50.

[0059] To ensure the airtightness of the filter 60 and prevent dust and moisture from entering, a ring of adhesive (such as epoxy glue) is poured around the seam between it and the PCB housing 50, and then it is dried and cured at 150°C for 2 hours.

[0060] In this embodiment, the substrate of the PCB base plate is preferably FR4 substrate, but other printed circuit board substrates may also be selected.

[0061] In this embodiment, the pyroelectric conditioning chip (also known as the pyroelectric signal conditioning chip) is a packaged chip or a bare chip assembled by COB, or it can be simplified to not having a chip attached.

[0062] In this embodiment, the conductive adhesive is preferably conductive silver paste or solder paste, but other conductive and curable adhesives may also be selected.

[0063] In this embodiment, the support pillar is preferably a silicon crystal pillar, but copper blocks, surface mount resistors, surface mount capacitors, and other conductive materials that can be mounted using SMT or die bond methods can also be selected. Copper blocks can be processed into small columnar structures, possessing good electrical and thermal conductivity. They can be used as support pillars and provide electrical connections through dispensing and curing. Surface mount resistors or capacitors are standard SMT components, consisting of rectangular ceramic bodies with metal terminals. Their advantages include standardized dimensions, ease of automated mounting (SMT equipment can directly grasp and place them), and fixation via reflow soldering or adhesive curing. Support pillars are not limited to silicon pillars; any material or component that can be mounted using SMT or die bond processes, possesses sufficient mechanical strength, and is conductive can be considered as a support pillar. This provides greater flexibility to the manufacturing process, especially facilitating compatibility with existing SMT production lines and improving production efficiency.

[0064] In this embodiment, the adhesive is preferably epoxy glue, but AB glue, UV glue, underfill glue or potting compound can also be selected.

[0065] In addition, to enhance structural strength (or to enhance the strength of the casing), adhesive is applied to the groove on the back of the PCB substrate. After curing or drying, the structural strength is increased.

[0066] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A patch-type manufacturing method for a pyroelectric sensor, characterized in that, include: Chip fixed; Conductive adhesive is printed on the chip pads of the PCB substrate, and the pyroelectric conditioning chip is mounted on the chip pads and fixed by reflow soldering. Fix the support column; apply conductive adhesive to the preset support point position on the PCB base plate, place the support column at the preset support point position, and dry and cure; Pyroelectric crystal fixing; apply conductive adhesive to the top of the fixed support column, attach the pyroelectric crystal to the top of the support column, and dry and cure. Frame fixing; apply conductive adhesive to the dispensing pads on the PCB base plate, align and attach the PCB frame to the PCB base plate, and dry and cure. Filter fixing; attach the filter to the top opening of the PCB enclosure.

2. The patch manufacturing method of the pyroelectric sensor as described in claim 1, characterized in that, The substrate of the PCB base plate is FR4 substrate; the pyroelectric conditioning chip is a packaged chip or a bare chip assembled by COB; the conductive adhesive is conductive silver paste or solder paste; the support pillar is a silicon crystal pillar, a copper pillar, a chip resistor or a chip capacitor.

3. The patch manufacturing method of the pyroelectric sensor as described in claim 1, characterized in that, It also includes enclosure sealing; adhesive is filled at the joint between the PCB base plate and the PCB enclosure, and then dried and cured.

4. The patch manufacturing method of the pyroelectric sensor as described in claim 1, characterized in that, It also includes filter sealing; a ring of adhesive is poured around the joint between the filter and the PCB housing, and then dried and cured.

5. The patch manufacturing method of the pyroelectric sensor as described in claim 3 or 4, characterized in that, The adhesive is epoxy glue, AB glue, UV glue, underfill glue, or potting compound.

6. The patch manufacturing method of the pyroelectric sensor as described in claim 1, characterized in that, The PCB enclosure is made of PCB substrate and manufactured through PCB drilling and through-hole metallization processes.

7. The patch manufacturing method of the pyroelectric sensor as described in claim 1, characterized in that, It also includes shell reinforcement: applying colloid into the groove on the back of the PCB base plate and drying and curing it.

8. A patch-type manufacturing method for a pyroelectric sensor, characterized in that, include: Enclosure fixed; Apply conductive adhesive to the dispensing pads on the PCB base plate, align and attach the PCB casing to the PCB base plate, and then dry and cure. Chip fixed; Conductive adhesive is printed on the chip pads of the PCB substrate, and the pyroelectric conditioning chip is mounted on the chip pads and fixed by reflow soldering. Fix the support column; apply conductive adhesive to the preset support point position on the PCB base plate, place the support column at the preset support point position, and dry and cure; Pyroelectric crystal fixing; apply conductive adhesive to the top of the fixed support column, attach the pyroelectric crystal to the top of the support column, and dry and cure. Filter fixing; attach the filter to the top opening of the PCB enclosure.

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