阅读说明：本技术 一种塑封温度传感器及其制备方法 (Plastic package temperature sensor and preparation method thereof ) 是由 龚逢源 张文兵 罗漫 马维维 魏文彪 张奇男 于 2021-06-01 设计创作，主要内容包括：本发明提供了一种塑封温度传感器,包括热敏芯片、引线组件和低压注塑层,所述热敏芯片与引线组件焊接,所述低压注塑层设置于所述热敏芯片外侧,且包裹所述热敏芯片以及与热敏芯片连接一端的部分引线组件,所述低压注塑层采用低压注塑加工成型。该发明采用低压注塑加工形成的低压注塑层包裹热敏芯片和部分引线组件,解决了传统树脂封装传感器元件引线绝缘,以及传统封装设计及制程中必须对传感器进行树脂涂覆、固化、灌封、再固化的复杂工序,且热态温度高时间长,导致实施自动化困难的问题。(The invention provides a plastic package temperature sensor which comprises a thermosensitive chip, a lead assembly and a low-pressure injection molding layer, wherein the thermosensitive chip is welded with the lead assembly, the low-pressure injection molding layer is arranged on the outer side of the thermosensitive chip and wraps the thermosensitive chip and part of the lead assembly at one end connected with the thermosensitive chip, and the low-pressure injection molding layer is formed by adopting low-pressure injection molding. The invention adopts the low-pressure injection molding layer formed by low-pressure injection molding processing to wrap the thermosensitive chip and part of the lead assembly, and solves the problems that the lead of the traditional resin-packaged sensor element is insulated, the complex procedures of resin coating, curing, encapsulating and re-curing are required to be carried out on the sensor in the traditional packaging design and manufacturing process, and the implementation automation is difficult due to high thermal state temperature and long time.)

1. The utility model provides a plastic envelope temperature sensor, its characterized in that, moulds plastics the layer including temperature sensing chip, lead wire subassembly and low pressure, temperature sensing chip and lead wire subassembly welding, the low pressure mould plastics the layer set up in the temperature sensing chip outside, and the parcel temperature sensing chip and with the temperature sensing chip be connected the partial lead wire subassembly of one end, the layer adopts low pressure injection moulding machine-shaping to mould plastics in the low pressure.

2. The plastic package temperature sensor according to claim 1, wherein the lead assembly is a hard lead, one end of the hard lead is welded to the thermal chip and wrapped inside the low-pressure injection layer, and the other end of the hard lead extends out of the low-pressure injection layer; the low-pressure injection molding layer is made of an epoxy low-pressure injection molding hard material containing heat-conducting porcelain powder.

3. The plastic package temperature sensor according to claim 1, wherein the lead assembly is a PVC insulated wire, one end of the PVC insulated wire is welded to the thermal chip and wrapped inside the low-pressure injection layer, and the other end of the PVC insulated wire extends outside the low-pressure injection layer; the low-pressure injection molding layer is made of polyamide low-pressure injection molding materials, and the PVC insulated conductor part wrapped in the low-pressure injection molding layer and the connecting interface of the low-pressure injection molding layer are mutually fused and integrally molded.

4. The plastic package temperature sensor of claim 1, wherein the lead assembly comprises a metallized ceramic, a nickel-plated steel wire, and a bonding wire, one side of the thermal chip is welded to the metallized surface of the metallized ceramic, the other side of the thermal chip is bonded to the metallized surface of the metallized ceramic through the bonding wire, one end of the nickel-plated steel wire is vertically welded to the metallized surface of the metallized ceramic, one end of the metallized surface of the metallized ceramic is wrapped in the low-pressure injection layer, one end of the nickel-plated steel wire welded to the metallized ceramic is wrapped in the low-pressure injection layer, and the other end of the nickel-plated steel wire extends out of the low-pressure injection layer; the low-pressure injection molding layer is made of a high-temperature modified low-pressure injection molding material.

5. A plastic package temperature sensor according to claim 1, wherein a waterproof silicone coating is attached to an outer surface of the lead assembly.

6. A method for manufacturing a plastic package temperature sensor according to any one of claims 1 to 5, comprising the following steps: firstly welding the thermosensitive chip and the lead assembly, and then coating the thermosensitive chip and one end of the lead assembly welded with the thermosensitive chip by injection molding through a low-pressure injection molding processing technology to form a low-pressure injection molding layer.

7. The method for manufacturing a plastic package temperature sensor according to claim 6, wherein for a rigid lead type plastic package temperature sensor, when the lead assembly is a rigid lead, the plastic package temperature sensor is manufactured as follows: arranging hard leads on a paper tape with hot melt adhesive at equal intervals, spraying soldering flux on the welding area of the hard leads, mounting a thermosensitive chip in the middle of the hard leads, clamping, ironing tin, performing appearance inspection after welding, performing resistance value comparison test in air, spraying a waterproof silica gel coating on the hard leads along a braid, drying, and performing low-pressure braid injection molding in a step feeding mode; the low-pressure injection molding material of the braid is an epoxy low-pressure injection molding hard material containing heat-conducting porcelain powder, a stepping thimble aluminum die is adopted in the low-pressure injection molding process, the low-pressure injection molding material of the braid is aligned step by step according to holes, the low-pressure injection molding material of the braid is a semifluid rubber block, the pressure of 10-17 bar is used, a pouring channel is cooled by cooling water at 5-15 ℃, the temperature of a die cavity is heated to 120-140 ℃, the time of each cavity is about 20S, then the low-pressure injection molding material of the braid is moved into a cutting die along with the braid, and a stub bar structure is cut off step by step according to the braid.

8. The method for manufacturing a plastic package temperature sensor according to claim 6, wherein when the lead assembly is a PVC insulated lead for the wire-sealed type plastic package temperature sensor, the process for manufacturing the plastic package temperature sensor is as follows: cutting the PVC insulated wires by an automatic wire cutting machine, placing the cut PVC insulated wires to corresponding stations by a clamping mechanism, arranging the PVC insulated wires at equal intervals, spraying soldering flux on welding areas of the arranged PVC insulated wires, installing a thermosensitive chip in the middle of the leads, clamping, burning tin, performing appearance inspection after welding, performing resistance value comparison test in air, spraying a waterproof silica gel coating on the hard leads, drying, and performing low-pressure injection molding; the material for low-pressure injection molding is polyamide low-pressure injection molding material, a stepping thimble aluminum mold is adopted in the low-pressure injection molding process, the material for low-pressure injection molding is gradually aligned according to holes, the material is polyamide low-pressure injection molding particles, the polyamide low-pressure injection molding particles are heated to 220-250 ℃ by a charging barrel and then injected into a mold cavity at a pressure of 2-8 bar, and the mold is removed after injection molding.

9. The method for manufacturing a plastic package temperature sensor according to claim 6, wherein when the lead wire assembly is a metallized ceramic, a nickel-plated steel wire or a bonding metal wire, the plastic package temperature sensor is manufactured as follows: firstly, metallizing the ceramic to form metallized ceramic, then welding one surface of the thermosensitive chip with the metallized surface, then welding the metallized surface of the ceramic with the nickel-plated steel wire, bonding the other surface of the thermosensitive chip with the metallized surface of the ceramic through a bonding metal wire after the bonding is finished, and finally placing the bonded sensor part into a low-pressure injection mold for low-pressure injection molding; the material for low-pressure injection molding is high-temperature modified low-pressure injection molding, a stepping thimble aluminum mold is adopted in the low-pressure injection molding process, the material for low-pressure injection molding is gradually aligned according to holes, the material is high-temperature modified low-pressure injection molding particles, the particles are heated to 220-250 ℃ by a charging barrel and then injected into a mold cavity at a pressure of 2-8 bar, and the particles are removed from the mold after injection molding.

Technical Field

The invention belongs to the technical field of temperature sensor manufacturing, and particularly relates to a plastic package temperature sensor and a preparation method thereof.

Background

NTC temperature sensor in the market at present generally adopts glass encapsulation or epoxy encapsulation to carry out resin class coating and filling separately after the encapsulation to guarantee the insulating of product and weatherability.

However, the conventional NTC temperature sensor packaging process has the following problems: (1) the sensor is required to be subjected to complex procedures of resin coating, curing, encapsulating and re-curing, and the thermal state temperature is high and long, so that the implementation automation is difficult; (2) the curing time of the coating material is long, the shape is irregular, and finally, the packaging process of the product needs a large amount of manual glue dispensing and glue supplementing, the process route greatly limits the production automation capacity in the field of temperature sensors, and limits the step of 3.0 to 4.0 transformation from factories to industries.

Disclosure of Invention

The invention aims to provide a plastic package temperature sensor which can at least solve part of problems in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a plastic envelope temperature sensor, includes temperature sensing chip, lead wire subassembly and the low pressure layer of moulding plastics, temperature sensing chip and lead wire subassembly welding, the low pressure layer of moulding plastics set up in the temperature sensing chip outside, and the parcel temperature sensing chip and the part lead wire subassembly of being connected one end with the temperature sensing chip, the low pressure layer of moulding plastics adopts low pressure injection moulding machine-shaping.

Furthermore, the lead assembly is a hard lead, one end of the hard lead is welded with the thermosensitive chip and wrapped inside the low-pressure injection layer, and the other end of the hard lead extends out of the low-pressure injection layer; the low-pressure injection molding layer is made of an epoxy low-pressure injection molding hard material containing heat-conducting porcelain powder.

Furthermore, the lead assembly is a PVC insulated wire, one end of the PVC insulated wire is welded with the thermosensitive chip and wrapped inside the low-pressure injection layer, and the other end of the PVC insulated wire extends out of the low-pressure injection layer; the low-pressure injection molding layer is made of polyamide low-pressure injection molding materials, and the PVC insulated conductor part wrapped in the low-pressure injection molding layer and the connecting interface of the low-pressure injection molding layer are mutually fused and integrally molded.

Further, the lead assembly comprises a metalized ceramic, a nickel-plated steel wire and a bonding metal wire, one side of the thermosensitive chip is welded with the metalized surface of the metalized ceramic, the other side of the thermosensitive chip is bonded with the metalized surface of the metalized ceramic through the bonding metal wire, one end of the nickel-plated steel wire is vertically welded on the metalized surface of the metalized ceramic, one end of the metalized surface of the metalized ceramic is wrapped in the low-pressure injection molding layer, one end of the nickel-plated steel wire welded with the metalized ceramic is wrapped in the low-pressure injection molding layer, and the other end of the nickel-plated steel wire extends out of the low-pressure injection molding layer; the low-pressure injection molding layer is made of a high-temperature modified low-pressure injection molding material.

Furthermore, a waterproof silica gel coating is attached to the outer surface of the lead assembly.

In addition, the invention also provides a preparation method of the plastic package temperature sensor, which comprises the following steps: firstly welding the thermosensitive chip and the lead assembly, and then coating the thermosensitive chip and one end of the lead assembly welded with the thermosensitive chip by injection molding through a low-pressure injection molding processing technology to form a low-pressure injection molding layer.

Specifically, for a hard lead type plastic package temperature sensor, when the lead assembly is a hard lead, the preparation process of the plastic package temperature sensor is as follows: arranging hard leads on a paper tape with hot melt adhesive at equal intervals, spraying soldering flux on the welding area of the hard leads, mounting a thermosensitive chip in the middle of the hard leads, clamping, ironing tin, performing appearance inspection after welding, performing resistance value comparison test in air, spraying a waterproof silica gel coating on the hard leads along a braid, drying, and performing low-pressure braid injection molding in a step feeding mode; the low-pressure injection molding material of the braid is an epoxy low-pressure injection molding hard material containing heat-conducting porcelain powder, a stepping thimble aluminum die is adopted in the low-pressure injection molding process, the low-pressure injection molding material of the braid is aligned step by step according to holes, the low-pressure injection molding material of the braid is a semifluid rubber block, the pressure of 10-17 bar is used, a pouring channel is cooled by cooling water at 5-15 ℃, the temperature of a die cavity is heated to 120-140 ℃, the time of each cavity is about 20S, then the low-pressure injection molding material of the braid is moved into a cutting die along with the braid, and a stub bar structure is cut off step by step according to the braid.

Specifically, for the wire sealing type plastic package temperature sensor, when the lead assembly is a PVC insulated wire, the plastic package temperature sensor is prepared as follows: cutting the PVC insulated wires by an automatic wire cutting machine, placing the cut PVC insulated wires to a corresponding station by a clamping mechanism, arranging the PVC insulated wires at equal intervals, spraying soldering flux on the welding area of the arranged PVC insulated wires, installing a thermosensitive chip in the middle of a lead, clamping, burning tin, performing appearance inspection after welding, performing resistance value comparison test in air, spraying a waterproof silica gel coating on the PVC insulated wires, drying, and performing low-pressure injection molding; the material for low-pressure injection molding is polyamide low-pressure injection molding material, a stepping thimble aluminum mold is adopted in the low-pressure injection molding process, the material for low-pressure injection molding is gradually aligned according to holes, the material is polyamide low-pressure injection molding particles, the polyamide low-pressure injection molding particles are heated to 220-250 ℃ by a charging barrel and then injected into a mold cavity at a pressure of 2-8 bar, and the mold is removed after injection molding.

Specifically, to plane temperature sensing extension type plastic envelope temperature sensor, when the lead wire subassembly is metallized ceramic, nickel-plated steel wire and bonding wire, plastic envelope temperature sensor preparation process is as follows: firstly, metallizing the ceramic to form metallized ceramic, then welding one surface of the thermosensitive chip with the metallized surface, then welding the metallized surface of the ceramic with the nickel-plated steel wire, bonding the other surface of the thermosensitive chip with the metallized surface of the ceramic through a bonding metal wire after the bonding is finished, and finally placing the bonded sensor part into a low-pressure injection mold for low-pressure injection molding; the material for low-pressure injection molding is a high-temperature modified low-pressure injection molding material, a stepping thimble aluminum mold is adopted in the low-pressure injection molding process, the material for low-pressure injection molding is gradually aligned according to holes, the material is high-temperature modified low-pressure injection molding particles, the particles are heated to 220-250 ℃ by a charging barrel and then injected into a mold cavity at a pressure of 2-8 bar, and the particles are removed from the mold after injection molding.

Compared with the prior art, the invention has the beneficial effects that:

(1) the plastic package temperature sensor provided by the invention adopts the low-pressure injection molding layer formed by low-pressure injection molding processing to wrap the thermosensitive chip and part of the lead wire assembly, and the epoxy resin coating and curing process is cancelled, so that the efficiency of the sensor is improved, the turnover is reduced, and the ratio of automation processes is improved in the production process.

(2) The plastic package temperature sensor provided by the invention adopts low-pressure injection molding polyamide or fused epoxy to carry out plastic package on the NTC chip and the lead wire bracket thereof, and utilizes the material melting point difference and the material bonding property to fuse a low-pressure injection molding body and a lead wire to form a sealing body, thereby omitting the process of package encapsulation.

(3) The primary insulation packaging shape and the volume of the plastic packaging temperature sensor are fixed, so that the plastic packaging temperature sensor can obtain good mounting operability in a scene of being directly mounted at a corresponding temperature sensing position; and in the scene of encapsulating the first insulating packaging head in other casings, because the volume is accurate, can adopt accurate some automatic production of gluing, avoid artifical benefit to glue the operation.

The present invention will be described in further detail below with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic structural diagram of a hard lead type plastic package temperature sensor according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of an internal structure of a hard lead type plastic package temperature sensor according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a wire-sealing type plastic-packaged temperature sensor according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a planar temperature-sensing expansion type plastic package temperature sensor according to an embodiment of the present invention;

FIG. 5 is an exploded view of a planar temperature sensing expansion type plastic encapsulated temperature sensor in an embodiment of the present invention;

fig. 6 is a schematic diagram of the installation of the thermosensitive chip of the planar temperature sensing expansion type plastic encapsulated temperature sensor in the embodiment of the invention.

Description of reference numerals: 1. a heat-sensitive chip; 2. a hard lead; 3. a low pressure injection molded layer; 4. PVC insulated wire; 5. a metallized ceramic; 6. nickel-plated steel wires; 7. and bonding the metal wires.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The invention provides a plastic package temperature sensor which comprises a thermosensitive chip 1, a lead assembly and a low-pressure injection molding layer 3, wherein the thermosensitive chip 1 is welded with the lead assembly, the low-pressure injection molding layer 3 is arranged on the outer side of the thermosensitive chip 1 and wraps the thermosensitive chip 1 and part of the lead assembly at one end connected with the thermosensitive chip 1, and the low-pressure injection molding layer 3 is formed by adopting low-pressure injection molding. According to the plastic package temperature sensor, the low-pressure injection molding layer 3 formed by low-pressure injection molding is used for wrapping the thermosensitive chip 1 and part of lead components, so that the problems that the lead of a traditional resin package sensor element is insulated, the traditional package design and the complex procedures of resin coating, curing, encapsulating and re-curing are required to be carried out on the sensor in the manufacturing process, the thermal state temperature is high, the time is long, and the implementation automation is difficult are solved.

Preferably, a waterproof silica gel coating is attached to the outer surface of the lead assembly, so that the waterproof performance of the plastic package temperature sensor is further improved.

In a specific embodiment, as shown in fig. 1 and 2, for the plastic-packaged temperature sensor of the hard lead type, the lead assembly is a hard lead 2, and the plastic-packaged temperature sensor is prepared by the following steps: firstly, arranging hard leads 2 on a paper tape with hot melt adhesive at equal intervals, then spraying soldering flux on a welding area of the hard leads 2, then installing a thermosensitive chip 1 in the middle of the hard leads 2 to clamp, burning tin, performing appearance inspection after welding, performing resistance value comparison test in air, spraying a waterproof silica gel coating on the hard leads 2 along a braid after the test meets the requirement, drying, and performing low-pressure injection molding on the braid in a step feeding manner to form a low-pressure injection molding layer 3; wherein the drying temperature is 105 ℃ and the drying time is 30 min.

In the low-pressure injection molding process of the braid of the hard lead type plastic package temperature sensor, the low-pressure injection molding layer 3 is made of an epoxy low-pressure injection molding hard material containing heat-conducting ceramic powder, and the specific technological process of low-pressure injection molding processing is as follows: the low-pressure injection molding adopts a stepping ejector pin aluminum mold, materials for low-pressure injection molding of the braid are aligned step by step according to holes, the material of the low-pressure injection molding layer 3 adopts a semi-fluid rubber block, the pressure of 10-17 bar is used, a pouring channel is cooled by using cooling water at 5-15 ℃, the temperature of a mold cavity is heated to 120-140 ℃, the heating time of each cavity is about 20S, then the material is moved into a cutting mold along with the braid, and a stub bar structure is cut off step by step according to the braid. By adopting the low-pressure injection molding process for the braid, 10-20 products can be injected at one time, large-scale automatic production is facilitated, and the production efficiency is improved.

The hard lead type plastic package temperature sensor adopts low-pressure injection molten epoxy to carry out plastic package on a thermosensitive chip 1 and a lead support thereof, can obtain a soldering lug element with an insulated lead and a regular shape through low-pressure injection with the lead support, and can be applied to the field of sensors needing film mounting; and the low-pressure injection molding layer reduces the number of packaging layers and is combined with the doping of ceramic powder, so that the consistency of the position, the heat transfer interface and the distance of the heat-conducting ceramic is better than that of the traditional resin coating process, and the algorithm compensation and accurate temperature control are easier to perform.

In a specific embodiment, for the wire-sealed plastic-packaged temperature sensor, as shown in fig. 3, the lead assembly is a PVC insulated wire 4, and the plastic-packaged temperature sensor is prepared by the following steps: the method comprises the following steps of cutting PVC insulated wires 4 by an automatic wire cutting machine, placing the cut PVC insulated wires 4 to corresponding stations by a clamping mechanism, arranging the PVC insulated wires at equal intervals, spraying soldering flux on welding areas of the arranged PVC insulated wires 4, mounting a thermosensitive chip 1 in the middle of a lead, clamping, burning tin, performing appearance inspection after welding, performing resistance value comparison test in air, spraying a waterproof silica gel coating on the PVC insulated wires 4 after the test meets the requirement, drying, and performing low-pressure injection molding to form a low-pressure injection molding layer 3; wherein the drying temperature is 105 ℃ and the drying time is 30 min.

In the low-pressure injection molding process of the wire sealing type plastic package temperature sensor, the low-pressure injection molding layer 3 is made of a polyamide low-pressure injection molding material, and the melting point of the polyamide low-pressure injection molding material is higher than that of a PVC insulated wire, so that the polyamide low-pressure injection molding material and the PVC insulated wire are mutually fused to form a very good sealing interface; the specific process of the low-pressure injection molding processing is as follows: the low-pressure injection molding adopts a stepping thimble aluminum mold, materials for low-pressure injection molding are gradually aligned according to holes, the materials of the low-pressure injection molding layer 3 adopt polyamide low-pressure injection molding particles, the polyamide low-pressure injection molding particles are heated to 220-250 ℃ by a charging barrel and then are injected into a mold cavity under the pressure of 2-8 bar, a runner adopts a high-temperature hot runner, a water-free opening is designed, and the high-temperature hot runner is moved out of the mold step by step along with a braid after the injection molding is completed, so that the sensor manufacturing can be completed.

The lead sealing type plastic package temperature sensor adopts low-pressure injection molding polyamide to carry out plastic package on the thermosensitive chip 1 and the lead support thereof, and utilizes the melting point difference and the material bonding property of materials to fuse the low-pressure injection molding layer 3 and the lead to form a sealed body, thereby omitting the process of package encapsulation.

In a specific embodiment, for a planar temperature sensing expansion type plastic package temperature sensor, as shown in fig. 4, 5 and 6, the lead components are a metallized ceramic 5, a nickel-plated steel wire 6 and a bonding metal wire 7, and the plastic package temperature sensor is prepared by the following steps: firstly metallizing the ceramic to form metallized ceramic 5, then welding one surface of the heat-sensitive chip 1 with the metallized surface, then welding the metallized plane of the ceramic with the nickel-plated steel wire 6, bonding the other surface of the heat-sensitive chip 1 with the metallized surface of the ceramic through a bonding metal wire 7 after the completion, and finally placing the bonded sensor part into a low-pressure injection mold for low-pressure injection molding to form a low-pressure injection molding layer 3.

In the low-pressure injection molding process of the plane temperature sensing expansion type plastic-sealed temperature sensor, the low-pressure injection molding material is a high-temperature modified low-pressure injection molding material, specifically, the high-temperature modified low-pressure injection molding material can be a low-pressure epoxy semi-solid injection molding block added with glass beads, and the specific technological process of low-pressure injection molding processing is as follows: the low-pressure injection molding adopts a stepping thimble aluminum mold, materials for low-pressure injection molding are gradually aligned according to holes, the materials of the low-pressure injection molding layer 3 adopt high-temperature modified low-pressure injection molding materials, the materials are heated to 220-250 ℃ by a charging barrel and then are injected into a mold cavity at a pressure of 2-8 bar, a runner adopts a high-temperature hot runner, a water-free opening is designed, and the materials are moved out of the mold step by step along with a braid after injection molding is completed, so that the sensor manufacturing can be completed.

In summary, the plastic package temperature sensor provided by the invention solves the problems of lead insulation of the traditional resin package sensor element, complex procedures of resin coating, curing, encapsulating and re-curing of the sensor in the traditional package design and manufacturing process, and difficult implementation automation caused by high thermal state temperature and long time.

The above examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention, which is intended to be covered by the claims and any design similar or equivalent to the scope of the invention.