Conductive composite foam and conductive probe assembly

Abstract

The present invention relates to the technical field of testing equipment, specifically disclosing a conductive composite foam and conductive probe assembly. The conductive composite foam comprises a foam body and a conductive fabric applied to the surface of the foam body to achieve electrical connection between a test circuit board and a device under test. The present invention provides a conductive composite foam and conductive probe assembly that can perform resistance testing on a device under test without damaging the surface of the device under test and has a long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of detection equipment, and in particular to a conductive combined foam and conductive probe assembly. Background Art

[0002] Many electronic products require good electrical conductivity. For example, a smart wristband with a heart rate measurement function requires good electrical conductivity (i.e., low resistance) for the bottom cover that fits against the wrist. Otherwise, the measured heart rate will be significantly deviated. Figure 1 , the current resistance detection process is as follows:

[0003] ① Press the positive probe 101 and the negative probe 102 against the two ends of the test piece 2 respectively;

[0004] ② Detect the resistance value between the positive probe 101 and the negative probe 102 through the detection circuit board 3.

[0005] The problem with the above process is that in step 1, the positive and negative probes currently used are both PIN needles. PIN needles are rigid metal structures, and the area of ​​the end that contacts the DUT is small. The pressure applied to the DUT is large, which can easily leave indentations on the surface of the DUT and even damage the DUT.

[0006] Currently, there are solutions on the market that use conductive silicone or gold-plated conductive cotton instead of PIN needles as probes to press the test piece. However, conductive silicone is a structure that uses glue to stick metal powder on silicone. Repeated squeezing easily causes powder to fall off, affecting the measurement results, and it is difficult to use it for a long time. Gold-plated conductive cotton has poor recovery ability and is prone to not rebound after repeated squeezing, resulting in a short service life.

[0007] Therefore, it is necessary to improve the existing probe to solve the problem that the use of traditional PIN needles as probes is easy to damage the device under test or has a short service life. Summary of the Invention

[0008] An object of the present invention is to provide a conductive composite foam and conductive probe assembly that can complete the resistance detection of a piece to be tested without causing damage to the surface of the piece to be tested and has a long service life.

[0009] To achieve the above objectives, the present invention provides a conductive composite foam, comprising:

[0010] Foam body;

[0011] Conductive cloth is applied to the surface of the foam body to achieve electrical connection between the detection circuit board and the device to be tested.

[0012] Preferably, the conductive cloth includes a polyester fiber layer and a metal copper layer located outside the polyester fiber layer.

[0013] Preferably, the conductive cloth comprises, from the inside out, a polyester fiber layer, a first nickel layer, a metal copper layer and a second nickel layer.

[0014] Preferably,

[0015] The first nickel layer is fixed to the surface of the polyester fiber layer by electroplating;

[0016] The metal copper layer is fixed on the surface of the first nickel layer by electroplating;

[0017] The second nickel layer is fixed on the surface of the metal copper layer by electroplating.

[0018] In another aspect, the present invention provides a conductive probe assembly, comprising any one of the above-mentioned conductive composite foams, and further comprising:

[0019] A fixing plate, the fixing plate being located above the conductive composite foam;

[0020] A metal compression block is provided between each of the conductive composite foams and the fixed plate; the top of the metal compression block is fixedly connected to the fixed plate, and the bottom is fixedly connected to the corresponding conductive composite foam; the metal compression block is electrically connected to the corresponding conductive composite foam.

[0021] Preferably, a positioning boss is provided on the top of the metal pressing block, and a positioning slot is provided on the fixing plate for inserting the positioning boss; the conductive probe assembly further comprises:

[0022] a housing, the housing being located above the fixing plate and being slidable up and down relative to the fixing plate;

[0023] A metal PIN needle is provided above each of the metal pressure blocks. The metal PIN needle is used to be electrically connected to the detection circuit board. The upper end of the metal PIN needle is fixed to the shell, and the lower end is inserted into the corresponding positioning groove. When the shell slides upward to the upper limit position relative to the fixing plate, the metal PIN needle disengages from the positioning boss. When the shell slides downward to the lower limit position relative to the fixing plate, the metal PIN needle contacts the positioning boss.

[0024] Preferably, it also includes:

[0025] A guide post, wherein the upper end of the guide post is fixedly connected to the shell, and the lower end of the guide post is connected to the fixing plate in an up-and-down sliding manner.

[0026] Preferably, a through hole is provided on the top of the shell, and the upper end of the metal PIN needle is located in the through hole.

[0027] Preferably, the fixing plate is provided with a bolt hole extending vertically therethrough, and the conductive probe assembly further comprises:

[0028] a limiting bolt, the limiting bolt comprising, in sequence, a bolt head located on a side of the fixing plate away from the housing, a smooth portion passing through the bolt hole, and a screw portion threadedly connected to the housing; the bolt head being larger than the through hole;

[0029] A compression spring is located between the housing and the fixing plate.

[0030] Preferably, the side of the foam body close to the metal compression block is divided into a bonding area and a conductive area, and the conductive cloth includes a lower conductive layer attached to the bottom of the foam body, an upper conductive layer attached to the conductive area, and a side conductive layer connecting the lower conductive layer and the upper conductive layer: the bonding area is provided with an adhesive layer connecting the foam body and the metal compression block.

[0031] The beneficial effects of the present invention are: providing a conductive composite foam and conductive probe assembly. On the one hand, the conductive cloth of the outer layer can achieve a good electrical connection with the test piece, facilitating resistance detection; the foam body of the inner layer has good cushioning performance and deformation ability, and will not generate excessive pressure on the surface of the test piece, so it will not damage the surface of the test piece; on the other hand, because the conductive cloth is used instead of metal powder, the conductive composite foam provided by this embodiment will not have the problem of powder shedding; furthermore, the foam body and the conductive cloth provided by this embodiment are independent of each other, and the internal structure of the foam body is not affected by the electroplating solution, so it can maintain good rebound performance. Therefore, the conductive composite foam and conductive probe assembly provided by the present invention can complete the resistance detection of the test piece without damaging the surface of the test piece, and has a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A schematic diagram of the structure of a PIN probe provided as background technology;

[0034] Figure 2 A schematic diagram of the structure of the conductive composite foam provided in the embodiment;

[0035] Figure 3A schematic cross-sectional view of a conductive composite foam provided in an embodiment;

[0036] Figure 4 A schematic diagram of two conductive probe assemblies provided in an embodiment detecting a piece of equipment to be tested;

[0037] Figure 5 A schematic diagram of the top structure of the conductive probe assembly provided in the embodiment;

[0038] Figure 6 A schematic diagram of the bottom structure of the conductive probe assembly provided in an embodiment;

[0039] Figure 7 for Figure 6 A partial enlarged schematic diagram of point A in the middle;

[0040] Figure 8 A schematic cross-sectional view of a conductive probe assembly provided in an embodiment.

[0041] In the picture:

[0042] 101, positive probe; 102, negative probe;

[0043] 2. Parts to be tested;

[0044] 3. Detect circuit boards;

[0045] 4. Conductive composite foam; 401. Foam body; 4011. Adhesive area; 402. Conductive fabric; 4021. Lower conductive layer; 4022. Upper conductive layer; 4023. Side conductive layer; 4024. Polyester fiber layer; 4025. First nickel layer; 4026. Copper metal layer; 4027. Second nickel layer;

[0046] 5. Fixed plate;

[0047] 6. Metal pressing block; 601. Positioning boss;

[0048] 700, conductive probe assembly;

[0049] 8. Shell;

[0050] 9. Metal PIN needle;

[0051] 10. Guide pillar;

[0052] 11. Limit bolt; 1101. Bolt head; 1102. Smooth part;

[0053] 12. Compression spring. DETAILED DESCRIPTION

[0054] In order to make the purposes, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0055] In the description of the present invention, it should be understood that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a centrally located component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be a centrally located component.

[0056] In addition, terms such as "long", "short", "inside", and "outside" indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention. They do not indicate or imply that the device or component referred to must have this specific orientation or operate in a specific orientation structure, and should not be understood as a limitation of the present invention.

[0057] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0058] This embodiment provides a conductive probe assembly, including a conductive composite foam. Figures 2 and 3 The conductive composite foam 4 includes a foam body 401 and a conductive cloth 402. The conductive cloth 402 is attached to the surface of the foam body 401 and is used to achieve electrical connection between the detection circuit board and the device under test 2.

[0059] Preferably, the foam body 401 is a flame-retardant sponge, which has good mechanical properties such as elasticity and flexibility.

[0060] The conductive composite foam 4 provided in this embodiment, on the one hand, has an outer conductive fabric 402 that enables a good electrical connection with the test piece 2, facilitating resistance testing. The inner foam body 401 has excellent cushioning and deformability, preventing excessive pressure on the surface of the test piece 2 and, therefore, preventing damage to the surface. Furthermore, because the conductive fabric 402 replaces metal powder, the conductive composite foam 4 provided in this embodiment is free from powder shedding. Research has found that directly electroplating foam can cause the plating solution to seep into the foam, resulting in a loss of resilience. The foam body 401 and the conductive fabric 402 provided in this embodiment are independent of each other, and the internal structure of the foam body 401 is unaffected by the plating solution, thus maintaining good resilience. Therefore, the conductive composite foam 4 provided in this embodiment can perform resistance testing on the test piece 2 without damaging the surface of the test piece 2 and has a long service life.

[0061] Furthermore, since foam is a common industrial material and is easy to process, the foam body 401 can be punched into any shape according to the needs of the test piece 2, making the conductive composite foam 4 more applicable. Optionally, the conductive composite foam 4 is crescent-shaped.

[0062] It should be noted that the conductive composite foam 4 provided in this embodiment is in surface contact with the device under test 2 , which has better test stability compared to traditional point contact.

[0063] Optionally, the conductive fabric 402 includes a polyester fiber layer 4024 and a metallic copper layer 4026 located outside the polyester fiber layer 4024. It is understood that the polyester fiber layer 4024 provides a substrate for the metallic copper layer 4026 to adhere to, while the metallic copper layer 4026 is primarily used to achieve electrical conduction between the device under test 2 and the conductive fabric 402. Furthermore, copper has a low electrical resistance, which can improve the accuracy of resistance detection of the device under test 2.

[0064] Furthermore, the conductive fabric 402 includes, from the inside out, a polyester fiber layer 4024, a first nickel layer 4025, a metallic copper layer 4026, and a second nickel layer 4027. It should be noted that nickel has excellent oxidation and corrosion resistance. The first nickel layer 4025 and the second nickel layer 4027 protect the metallic copper layer 4026 from oxidation and corrosion, thereby reducing the humidity requirements of the conductive composite foam 4.

[0065] Optionally, the first nickel layer 4025 is fixed to the surface of the polyester fiber layer 4024 by electroplating; the metal copper layer 4026 is fixed to the surface of the first nickel layer 4025 by electroplating; and the second nickel layer 4027 is fixed to the surface of the metal copper layer 4026 by electroplating.

[0066] It is understandable that the electroplating processing method can not only ensure the connection reliability between the layers and prevent them from falling off, but also minimize the contact resistance between the layers, greatly improving the conductive performance of the conductive cloth 402 and improving the accuracy of the detection results.

[0067] Understandably, see Figure 4 When performing resistance testing on a DUT 2, two conductive probe assemblies 700 should be used in pairs. Specifically, two conductive probe assemblies 700, one above the other and one below the other, should be used to clamp the DUT 2 for testing. For ease of description, this embodiment uses the conductive probe assembly 700 located above as an example.

[0068] See also Figures 5 to 8 In this embodiment, the conductive probe assembly 700 further includes a fixing plate 5 and a metal compression block 6. The fixing plate 5 is positioned above the conductive composite foam 4. A metal compression block 6 is positioned between each conductive composite foam 4 and the fixing plate 5. The top of each metal compression block 6 is fixedly connected to the fixing plate 5, and the bottom is fixedly connected to the corresponding conductive composite foam 4. The metal compression block 6 is electrically connected to the corresponding conductive composite foam 4.

[0069] Specifically, the fixing plate 5 is made of insulating material.

[0070] Optionally, depending on the number of detection points on the test piece 2, one, two, three, four or even more conductive composite foams 4 may be provided.

[0071] The metal pressing blocks 6 both electrically connect the conductive fabric 402 to the test circuit board and press the corresponding conductive composite foam pads 4 against the surface of the test object 2. To perform a resistance test on the test object 2, the test object 2 is placed between the two conductive probe assemblies 700. The fixing plate 5 moves downward relative to the test object 2 until the conductive composite foam pads 4 press against the test object 2. The test circuit board then passes through the metal pressing blocks 6 for resistance testing.

[0072] It can be understood that the fixing plate 5 provides a flat fixing surface for each metal pressing block 6, thereby ensuring that the lower surface of the conductive composite foam 4 connected to the bottom of each metal pressing block 6 is flush, that is, when the horizontally placed fixing plate 5 is lowered a certain distance, the pressure applied by each conductive composite foam 4 to the test piece 2 is almost the same, avoiding uneven force on different parts of the test piece 2 and the occurrence of damage due to stress concentration.

[0073] Optionally, a positioning boss 601 is provided on the top of the metal pressure block 6, and a positioning slot is provided on the fixing plate 5 for inserting the positioning boss 601. The conductive probe assembly 700 also includes a shell 8 and a metal PIN needle 9. The shell 8 is located above the fixing plate 5 and can slide up and down relative to the fixing plate 5. A metal PIN needle 9 is provided above each of the metal pressure blocks 6. The metal PIN needle 9 is used to be electrically connected to the detection circuit board, with its upper end fixed to the shell 8 and its lower end inserted into the corresponding positioning slot; when the shell 8 slides upward to the upper limit position relative to the fixing plate 5, the metal PIN needle 9 disengages from the positioning boss 601; when the shell 8 slides downward to the lower limit position relative to the fixing plate 5, the metal PIN needle 9 contacts the positioning boss 601.

[0074] Optionally, a drive device such as a cylinder or a motor may be provided, the drive end of which is connected to the housing 8 for driving the housing 8 to move up and down. Furthermore, the conductive probe assembly 700 further includes a guide post 10, the upper end of which is fixedly connected to the housing 8 and the lower end of which is slidably connected to the fixing plate 5.

[0075] Preferably, a through hole is provided on the top of the housing 8, and the upper end of the metal PIN needle 9 is located in the through hole. Specifically, exposing the metal PIN needle 9 in the through hole can facilitate electrical connection with the corresponding contact on the detection circuit board.

[0076] Furthermore, the fixing plate 5 is provided with a bolt hole extending vertically therethrough. The conductive probe assembly 700 also includes a retaining bolt 11 and a compression spring 12. The retaining bolt 11 comprises, in sequence, a bolt head 1101 located on the side of the fixing plate 5 away from the housing 8, a smooth portion 1102 that passes through the bolt hole, and a screw portion that is threadedly connected to the housing 8. The bolt head 1101 is larger than the through hole and cannot pass through it, thereby acting as a retaining force to prevent the fixing plate 5 from separating from the housing 8. The compression spring 12 is located between the housing 8 and the fixing plate 5.

[0077] In this embodiment, the metal PIN needles 9 are used to achieve electrical connection between the test circuit board and the metal pressing block 6. Specifically, the driving device drives the housing 8 downward. When each conductive composite foam 4 contacts the DUT 2, the foam body 401 in each conductive composite foam 4 is squeezed until each foam body 401 is squeezed to its limit. The fixed plate 5 remains stationary relative to the DUT 2, while the housing 8 continues to move downward under the drive of the driving device. The metal PIN needles 9 move downward with the housing 8 relative to the fixed plate 5 until they press against the corresponding positioning boss 601. The driving device stops moving, and the metal PIN needles 9 maintain contact with the positioning boss 601. The test circuit board then detects the DUT 2 through the metal PIN needles 9, the metal pressing block 6, and the conductive composite foam 4 in sequence. During the above-mentioned detection process, it should be noted that the foam body 401 can prevent rigid contact between the metal clamping block 6 and the test piece 2, thereby avoiding damage to the test piece 2. The compression spring 12 can act as a buffer, reducing the impact of the metal PIN needle 9 on the positioning boss 601, and protecting the metal clamping block 6 and the metal PIN needle 9 from damage.

[0078] In this embodiment, the side of the foam body 401 close to the metal pressing block 6 is divided into a bonding area 4011 and a conductive area, and the conductive cloth 402 includes a lower conductive layer 4021 attached to the bottom of the foam body 401, an upper conductive layer 4022 attached to the conductive area, and a side conductive layer 4023 connecting the lower conductive layer 4021 and the upper conductive layer 4022: the bonding area 4011 is provided with an adhesive layer connecting the foam body 401 and the metal pressing block 6.

[0079] It can be understood that the upper surface of the foam body 401 is divided into two parts, one side is used to achieve fixed connection with the metal fixing block, and the other side is used to achieve electrical connection with the metal fixing block. The overall structure is simple and compact, and no other connecting components are required, thereby improving the structural compactness of the conductive probe assembly 700.

[0080] Furthermore, since the conductive composite foam 4 is fixed to the metal compression block 6 through the adhesive layer, when the conductive composite foam 4 needs to be replaced, the old conductive composite foam 4 can be directly torn off and a new conductive composite foam 4 can be attached, and the replacement process is simple and convenient.

[0081] The conductive probe assembly 700 provided in this embodiment has the following advantages:

[0082] ① The conductive composite foam 4 has good corrosion resistance and oxidation resistance, and has lower requirements for environmental humidity, which can effectively extend the service life and reduce costs. It can also be punched into any shape according to demand, and has a wider applicability;

[0083] ② The conductive composite foam 4 is formed by wrapping the flame retardant sponge with a conductive cloth 402. The conductive composite foam 4 has excellent surface conductivity and can be easily fixed on the metal fixing block with adhesive tape, etc., making maintenance and replacement very convenient.

[0084] ③ The conductive composite foam 4 has good mechanical properties such as elasticity and flexibility, and has a large compression range, which can be compressed to a maximum of 60% of the original thickness, which can effectively prevent damage to the test piece 2;

[0085] ④ The electrostatic protection performance of the test piece 2 is both permanent and meets the flame retardant grade (UL94-V0) and complies with RoHS.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A conductive probe assembly, comprising: Several conductive composite foams, the conductive composite foams comprising: Foam body; Conductive cloth, which is applied to the surface of the foam body and is used to achieve electrical connection between the test circuit board and the device to be tested; A fixing plate, the fixing plate being located above the conductive composite foam; A metal compression block is provided between each of the conductive composite foams and the fixing plate; the top of the metal compression block is fixedly connected to the fixing plate, and the bottom is fixedly connected to the corresponding conductive composite foam; the metal compression block is electrically connected to the corresponding conductive composite foam; wherein the top of the metal compression block is provided with a positioning boss, and the fixing plate is provided with a positioning slot for inserting the positioning boss; a housing, the housing being located above the fixing plate and being slidable up and down relative to the fixing plate; A metal PIN needle is provided above each of the metal pressure blocks. The metal PIN needle is used to be electrically connected to the detection circuit board. The upper end of the metal PIN needle is fixed to the shell, and the lower end is inserted into the corresponding positioning groove. When the shell slides upward to the upper limit position relative to the fixing plate, the metal PIN needle disengages from the positioning boss. When the shell slides downward to the lower limit position relative to the fixing plate, the metal PIN needle contacts the positioning boss.

2. The conductive probe assembly according to claim 1, wherein: Also includes: A guide post, wherein the upper end of the guide post is fixedly connected to the shell, and the lower end of the guide post is connected to the fixing plate in an up-and-down sliding manner.

3. The conductive probe assembly according to claim 1, wherein: A through hole is provided on the top of the shell, and the upper end of the metal PIN is located in the through hole.

4. The conductive probe assembly according to claim 3, wherein: The fixing plate is provided with bolt holes extending vertically therethrough, and the conductive probe assembly further comprises: a limiting bolt, the limiting bolt comprising, in sequence, a bolt head located on a side of the fixing plate away from the housing, a smooth portion passing through the bolt hole, and a screw portion threadedly connected to the housing; the bolt head being larger than the through hole; A compression spring is located between the housing and the fixing plate.

5. The conductive probe assembly according to claim 1, wherein: The side of the foam body close to the metal compression block is divided into a bonding area and a conductive area. The conductive cloth includes a lower conductive layer attached to the bottom of the foam body, an upper conductive layer attached to the conductive area, and a side conductive layer connecting the lower conductive layer and the upper conductive layer: the bonding area is provided with an adhesive layer connecting the foam body and the metal compression block.

6. The conductive probe assembly according to claim 1, wherein: The conductive cloth includes a polyester fiber layer and a metal copper layer located outside the polyester fiber layer.

7. The conductive probe assembly according to claim 6, wherein: The conductive cloth comprises, from the inside out, a polyester fiber layer, a first nickel layer, a metal copper layer, and a second nickel layer.

8. The conductive probe assembly according to claim 7, wherein: The first nickel layer is fixed to the surface of the polyester fiber layer by electroplating; The metal copper layer is fixed on the surface of the first nickel layer by electroplating; The second nickel layer is fixed on the surface of the metal copper layer by electroplating.

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