Humidity sensor packaging structure, packaging method and powder block substrate

Abstract

The invention discloses a humidity sensor packaging structure, a packaging method and a powder block substrate. The four pins and the base ring are placed in corresponding positioning positions according to positioning points of a pressing mold; the powder block base plate penetrates through the pin and is placed in the base ring, the pressure of a pressing machine is set to be 1-4 ton, the pressing machine presses the powder block base plate, the pressing time is 1-10 s, the powder block base plate and the base ring are pressed and fixed, and an assembled sample piece is obtained; putting the assembled sample piece into a box-type furnace, sintering the assembled sample piece at 550-690 DEG C for 2-5H, and sintering the assembled sample piece into a whole to obtain a sample table; connecting wires are welded on pins of the chip in a resistance welding mode, the pins of the chip are made of platinum paste electrodes, and platinum wires with the diameter ranging from 0.1 mm to 0.4 mm are adopted as the connecting wires; placing a thermal insulation material on the sample table, and supporting the chip; the other ends of the connecting wires are welded to the tops of all the pins in the electric resistance welding mode; and the waste cover is arranged on the base ring in a sleeving mode, circumferential resistance welding is conducted along the skirt edge of the waste cover, and integrated packaging is completed.

Description

Technical field:

[0001] The invention belongs to the technical field of humidity sensor packaging, and in particular relates to a humidity sensor packaging structure, a packaging method and a powder block substrate. Background technology:

[0002] In recent years, during the process of cooking food in a steam-bake machine, the appropriateness of the internal water vapor content is one of the key control factors that determine the freshness and tenderness of the food. Therefore, humidity sensors used in steam-bake machines are indispensable, and their humidity monitoring data is an important parameter for measuring, feedback and regulating the water vapor content.

[0003] The internal environment of the steam oven is high temperature and high humidity. Under this condition, traditional humidity-sensitive chips are no longer suitable for humidity monitoring of the steam oven. The zirconia limiting current type oxygen sensor is based on the linear relationship between the oxygen partial pressure in high-temperature air and its humidity. It can measure the oxygen concentration in the high-temperature environment to indicate the humidity of the high-temperature environment, and then act as a humidity sensor for monitoring humidity. With the development trend of the industry field that requires intelligent and highly integrated micro-electromechanical systems for data collection and control in the assembly of steam ovens, the corresponding requirements for miniaturization, low power consumption, and integration of sensors are also getting higher and higher. The conventional zirconia limiting current type humidity sensor uses ceramic tube clamping positioning and metal tube shell packaging technology, such as Figure 1 As shown, the process is relatively complex and the manufacturing cost is relatively high, which is very unfavorable for the popularization and integrated application promotion of such humidity sensors. Therefore, how to develop a small-sized, low-power, and integrated humidity sensor package for steam-bake machines has become an urgent problem to be solved.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention:

[0005] The object of the present invention is to provide a humidity sensor packaging structure, a packaging method and a powder block substrate, so as to overcome the defects in the above-mentioned prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides a humidity sensor packaging structure, including a shell, a powder block substrate, pins, and a chip. The shell is provided with a detection hole, and a chip is provided in the shell. The chip and the pins are connected by connecting wires. The powder block substrate is packaged at the opening at the lower end of the shell, the chip is arranged on the top of the powder block substrate, the pins are inserted into the powder block substrate, and the pins extend from the inside of the shell to the outside of the shell.

[0007] Preferably, in the technical solution, a thermal insulation pad is provided on the top of the powder block substrate, and a chip is placed on the thermal insulation pad. The thermal insulation pad isolates the chip from the powder block substrate to avoid direct diffusion and transmission loss of heat through the powder block substrate.

[0008] Preferably, in the technical solution, the chip includes a sensing electrode, a top pin electrode, and a bottom pin electrode. The sensing electrode is located on the top of the chip, the sensing electrode is connected to the top pin electrode, and the top pin electrode and the bottom pin electrode are respectively connected to corresponding pins through connecting wires.

[0009] Preferably, in the technical solution, the part of the pin located in the powder block substrate is provided with an enhanced fixing structure, and the enhanced fixing structure is a convex-concave-convex structure. Correspondingly, a corresponding concave-convex-concave clamping structure is provided on the powder block substrate to enhance the clamping and fixation of the pin by the powder block substrate.

[0010] Preferably, in the technical solution, a circular groove is provided at the bottom of the pin, so that the pin can be connected to the circuit substrate by welding, and can also be inserted into the wire harness to realize the free installation of the humidity sensor over long and short distances.

[0011] Preferably, in the technical solution, the outer shell includes an exhaust gas hood and a base ring, the exhaust gas hood is connected to the base ring, and a skirt structure is provided at the connection between the exhaust gas hood and the base ring to facilitate the connection between the exhaust gas hood and the base ring; a detection hole is provided on the top of the exhaust gas hood; an installation groove is provided on the inner wall of the base ring, and a corresponding raised installation ring is provided on the outer surface of the powder block substrate, and the installation ring cooperates with the installation groove to enhance the fixation and clamping of the powder block substrate by the base ring.

[0012] The packaging method of the humidity sensor comprises the following steps: (1) placing four pins and a base ring into corresponding positioning positions according to positioning points of a pressing mold;

[0013] (2) The powder block substrate is placed in the base ring through the pins, the press pressure is set to 1-4 tons, the press presses the powder block substrate, the pressing time is 1-10 seconds, the powder block substrate and the base ring are pressed and fixed to obtain an assembled sample;

[0014] (3) placing the assembled sample obtained in step (2) into a box-type furnace, sintering the assembled sample at 550-690° C. for 2-5 hours, sintering the assembled sample into one piece, and obtaining a sample stage;

[0015] (4) Weld the chip pins to the connecting wires by resistance welding. The chip pins are made of platinum paste electrodes, and the connecting wires are made of platinum wires with a diameter of 0.1-0.4 mm;

[0016] (5) placing a heat-insulating material on the sample table obtained in step (3) to support the chip welded in step (4);

[0017] (6) Weld the other end of the connecting wire 7 to the top of each pin by resistance welding;

[0018] (7) After completing the operation of step (6), the waste cover is put on the base ring, and circumferential resistance welding is performed along the skirt of the waste cover to complete the integrated packaging.

[0019] The powder block substrate of the humidity sensor comprises the following components by mass: 50-80% of talc powder, 5-15% of boron oxide, 2-10% of bismuth oxide, 2-10% of zinc oxide and 0.5-3% of a binder.

[0020] Preferably, in the technical solution, the binder is polyvinyl alcohol or methyl cellulose.

[0021] A method for preparing a humidity sensor powder block substrate comprises the following steps:

[0022] (1) mixing talc powder, boron oxide, bismuth oxide, and zinc oxide in a mass ratio of 50-80%, 5-15%, 2-10%, and 2-10% to obtain a mixed powder;

[0023] (2) adding the mixed powder and a binder solution having a mass ratio of 5-15% to a mixer in a mass ratio of 100:0.5-3, stirring at 80 rpm for 10-30 min in the mixer to obtain a mixture;

[0024] (3) Add the mixed material into the granulator at a pressure of 0.3-0.8 ton / cm 2 The mixed material is pre-pressed, crushed and then granulated under the following conditions, the discharge rate is 1-2kg / min, and the granules obtained after granulation are screened through a 40-100 mesh sieve;

[0025] (4) placing the pellets obtained in step (3) into an oven and drying at 100° C. for 10-30 min to obtain a dry powder block;

[0026] (5) Add the dried powder block into the substrate mold, adjust the press pressure to 1-2.5 tons, and press the powder block in the substrate mold for 1-10 seconds to obtain a powder block substrate with four symmetrical pin holes.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention designs a small-size, low-power, integrated humidity sensor packaging structure, designs a powder block formula, and uses the powder block to press and low-temperature sinter a packaging substrate to propose a new, simple, easy to obtain, and low-cost packaging method. Description of the drawings:

[0029] Figure 1It is a schematic diagram of the structure of an existing humidity sensor;

[0030] Figure 2 This is a schematic diagram of the packaging structure of the humidity sensor of the present invention;

[0031] Figure 3 It is a cross-sectional view of the packaging structure of the humidity sensor of the present invention;

[0032] Figure 4 It is a schematic diagram of the powder block substrate structure of the present invention. Specific implementation method:

[0033] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0034] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0035] like Figure 2-3 As shown, the humidity sensor packaging structure includes a shell, a powder block substrate 4, a pin 3, a chip 6, and a heat-insulating pad 5. The shell is provided with a detection hole 11, and a chip 6 is provided in the shell. The chip 6 is connected to the pin 3 through a connecting wire 7. The powder block substrate 4 is encapsulated at the opening of the lower end of the shell. A heat-insulating pad 5 is provided on the top of the powder block substrate 4. The chip 6 is placed on the heat-insulating pad 5. The heat-insulating pad 5 isolates the chip 6 from the powder block substrate 4 to avoid heat directly diffusing and transmitting through the powder block substrate 4. The pin 3 is inserted into the powder block substrate 4, and the pin 3 extends from the inside of the shell to the outside of the shell. The chip 6 shown includes a sensing electrode 61, a top pin electrode 62, and a bottom pin electrode 63. The sensing electrode 61 is located at the top of the chip 6, and the sensing electrode 61 is connected to the top pin electrode 62. The top pin electrode 62 and the bottom pin electrode 63 are respectively connected to the corresponding pin 3 through the connecting wire 7.

[0036] The part of the pin 3 located in the powder block substrate 4 is provided with an enhanced fixing structure, which is a convex-concave-convex structure. Correspondingly, a corresponding concave-convex-concave clamping structure is provided on the powder block substrate 4 to enhance the clamping and fixing of the pin 3 by the powder block substrate 4. A circular groove 31 is provided at the bottom of the pin 3, so that the pin 3 can be welded and connected to the circuit substrate, and can also be inserted into the wire harness to realize the free installation of the humidity sensor over a long or short distance.

[0037] The shell includes an exhaust gas hood 1 and a base ring 2. The exhaust gas hood 1 is connected to the base ring 2. A skirt structure 12 is provided at the connection between the exhaust gas hood 1 and the base ring 2 to facilitate the connection between the exhaust gas hood 1 and the base ring 2. A detection hole 11 is provided on the top of the exhaust gas hood 1. A mounting groove 21 is provided on the inner wall of the base ring 2, and a corresponding raised mounting ring is provided on the outer surface of the powder block substrate 4. The mounting ring cooperates with the mounting groove 21 to enhance the fixation and clamping of the base ring 2 on the powder block substrate 4.

[0038] The packaging method of the humidity sensor comprises the following steps: (1) placing four pins and a base ring into corresponding positioning positions according to positioning points of a pressing mold;

[0039] (2) The powder block substrate is placed in the base ring through the pins, the press pressure is set to 1-4 tons, the press presses the powder block substrate, the pressing time is 1-10 seconds, the powder block substrate and the base ring are pressed and fixed to obtain an assembled sample;

[0040] (3) placing the assembled sample obtained in step (2) into a box-type furnace, sintering the assembled sample at 550-690° C. for 2-5 hours, sintering the assembled sample into one piece, and obtaining a sample stage;

[0041] (4) Weld the chip pins to the connecting wires by resistance welding. The chip pins are made of platinum paste electrodes, and the connecting wires are made of platinum wires with a diameter of 0.1-0.4 mm;

[0042] (5) placing a heat-insulating material on the sample table obtained in step (3) to support the chip welded in step (4);

[0043] (6) Weld the other end of the connecting wire 7 to the top of each pin by resistance welding;

[0044] (7) After completing the operation of step (6), the waste cover is put on the base ring, and circumferential resistance welding is performed along the skirt of the waste cover to complete the integrated packaging.

[0045] The powder block substrate of the humidity sensor comprises the following components by mass: 50-80% of talc powder, 5-15% of boron oxide, 2-10% of bismuth oxide, 2-10% of zinc oxide and 0.5-3% of a binder; the binder is polyvinyl alcohol or methyl cellulose.

[0046] A method for preparing a humidity sensor powder block substrate comprises the following steps:

[0047] (1) mixing talc powder, boron oxide, bismuth oxide, and zinc oxide in a mass ratio of 50-80%, 5-15%, 2-10%, and 2-10% to obtain a mixed powder;

[0048] (2) adding the mixed powder and a binder solution having a mass ratio of 5-15% to a mixer in a mass ratio of 100:0.5-3, stirring at 80 rpm for 10-30 min in the mixer to obtain a mixture;

[0049] (3) Add the mixed material into the granulator at a pressure of 0.3-0.8 ton / cm 2 The mixed material is pre-pressed, crushed and then granulated under the following conditions, the discharge rate is 1-2kg / min, and the granules obtained after granulation are screened through a 40-100 mesh sieve;

[0050] (4) placing the pellets obtained in step (3) into an oven and drying at 100° C. for 10-30 min to obtain a dry powder block;

[0051] (5) Add the dried powder block to the substrate mold, adjust the press pressure to 1-2.5 tons, and press the powder block in the substrate mold for 1-10 seconds to obtain a powder block substrate with four symmetrical pin holes, such as Figure 4 shown.

[0052] The present invention designs a small-size, low-power, integrated humidity sensor packaging structure, designs a powder block formula, and uses the powder block to press and low-temperature sinter a packaging substrate to propose a new, simple, easy to obtain, and low-cost packaging method.

[0053] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A humidity sensor packaging structure, characterized in that: It includes a shell, a powder block substrate, pins, and a chip. The shell is provided with a detection hole, the shell is provided with a chip, the chip and the pins are connected by connecting wires, the powder block substrate is encapsulated at the opening at the lower end of the shell, the chip is arranged on the top of the powder block substrate, the pins are inserted into the powder block substrate, and the pins extend from the inside of the shell to the outside of the shell.

2. The humidity sensor packaging structure according to claim 1, characterized in that: A heat-insulating pad is arranged on the top of the powder block substrate, and a chip is placed on the heat-insulating pad, and the heat-insulating pad isolates the chip from the powder block substrate.

3. The humidity sensor packaging structure according to claim 1, characterized in that: The chip includes a sensing electrode, a top pin electrode, and a bottom pin electrode. The sensing electrode is located on the top of the chip and is connected to the top pin electrode. The top pin electrode and the bottom pin electrode are respectively connected to corresponding pins through connecting wires.

4. The humidity sensor packaging structure according to claim 1, characterized in that: The part of the pin located in the powder block substrate is provided with an enhanced fixing structure, which is a convex-concave-convex structure. Correspondingly, a corresponding concave-convex-concave clamping structure is provided on the powder block substrate.

5. The humidity sensor packaging structure according to claim 1, characterized in that: A circular groove is arranged at the bottom of the pin.

6. The humidity sensor packaging structure according to claim 1, characterized in that: The outer shell includes an exhaust gas hood and a base ring. The exhaust gas hood is connected to the base ring. A skirt structure is provided at the connection between the exhaust gas hood and the base ring to facilitate the connection between the exhaust gas hood and the base ring. A detection hole is provided on the top of the exhaust gas hood. An installation groove is provided on the inner wall of the base ring, and a corresponding raised installation ring is provided on the outer surface of the powder block substrate.

7. A method for packaging a humidity sensor packaging structure, using the humidity sensor packaging structure according to any one of claims 1 to 6, the steps of which are: (1) placing four pins and a base ring into corresponding positioning positions according to positioning points of a pressing mold; (2) The powder block substrate is placed in the base ring through the pins, the press pressure is set to 1-4 tons, the press presses the powder block substrate, the pressing time is 1-10 seconds, the powder block substrate and the base ring are pressed and fixed to obtain an assembled sample; (3) placing the assembled sample obtained in step (2) into a box-type furnace, sintering the assembled sample at 550-690° C. for 2-5 hours, sintering the assembled sample into one piece, and obtaining a sample stage; (4) Weld the chip pins to the connecting wires by resistance welding. The chip pins are made of platinum paste electrodes, and the connecting wires are made of platinum wires with a diameter of 0.1-0.4 mm; (5) placing a heat-insulating material on the sample table obtained in step (3) to support the chip welded in step (4); (6) Weld the other end of the connecting wire 7 to the top of each pin by resistance welding; (7) After completing the operation of step (6), the waste cover is put on the base ring, and circumferential resistance welding is performed along the skirt of the waste cover to complete the integrated packaging.

8. Humidity sensor powder block substrate, characterized in that: Used in the humidity sensor packaging structure as described in any one of claims 1 to 6, its mass components are 50-80% talc powder, 5-15% boron oxide, 2-10% bismuth oxide, 2-10% zinc oxide and 0.5-3% binder.

9. The humidity sensor powder block substrate according to claim 8, characterized in that: The binder is polyvinyl alcohol or methyl cellulose.

10. A method for preparing a humidity sensor powder block substrate, comprising the steps of: (1) mixing talc powder, boron oxide, bismuth oxide, and zinc oxide in a mass ratio of 50-80%, 5-15%, 2-10%, and 2-10% to obtain a mixed powder; (2) adding the mixed powder and a binder solution having a mass ratio of 5-15% to a mixer in a mass ratio of 100:0.5-3, stirring at 80 rpm for 10-30 min in the mixer to obtain a mixture; (3) Add the mixed material into the granulator and press it at a pressure of 0.3-0.8 ton / cm 2 The mixed material is pre-pressed, crushed and then granulated under the following conditions, the discharge rate is 1-2kg / min, and the granulated material is screened through a 40-100 mesh sieve; (4) placing the pellets obtained in step (3) into an oven and drying at 100° C. for 10-30 min to obtain a dry powder block; (5) Add the dried powder block into the substrate mold, adjust the press pressure to 1-2.5 tons, and press the powder block in the substrate mold for 1-10 seconds to obtain a powder block substrate with four symmetrical pin holes.

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