Probe fixing structure formed by stacking plurality of printed circuit boards

Abstract

The utility model provides a probe fixing structure formed by stacking a plurality of printed circuit boards, which belongs to the field of test jigs of power modules and comprises a plurality of printed circuit boards, hole sites are arranged on the printed circuit boards, the plurality of printed circuit boards are stacked along the axial direction of a probe, and the probe is arranged in the hole sites in a penetrating manner. By stacking the printed circuit boards, the thickness of the printed circuit boards can be equivalently increased, when n printed circuit boards are stacked, the tangent value can be reduced to 1 / n of the original tangent value, and the inclination angle of the probe in the hole site is reduced, so that the perpendicularity of the probe during installation is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of a test fixture for a power module, in particular to a probe fixing structure. Background Art

[0002] With the development of technology, the application of power semiconductor IGBT and MOSFET modules has become increasingly popular. The reliability of the device needs to be evaluated during the device development process, manufacturing process and before application. Before conducting an electrical evaluation, the device under test needs to be electrically connected to the test equipment through a fast, non-permanent connection method.

[0003] The commonly used connection method is to connect the electrical interface of the test equipment to a specific printed circuit board, and then use the spring probe installed on the printed circuit board to make an electrical connection with the device under test. When using a single printed circuit board for connection, since the common thickness of the printed circuit board is 1.6mm and the maximum manufacturable industry standard is 2.0mm, relative to the probe with a diameter of more than 3mm, under the conditions of limited printed circuit board thickness and aperture tolerance, the installation of the probe is prone to skew, which leads to problems such as difficulty in assembly, low quality, and high rework rate. Utility Model Content

[0004] The technical problem to be solved by the utility model is how to solve the problem of great assembly difficulty, low quality and high rework rate caused by the easy tilt of the probe during installation.

[0005] The utility model solves the above technical problems through the following technical solutions: a probe fixing structure composed of multiple printed circuit boards stacked, comprising multiple printed circuit boards, each of which has holes, the multiple printed circuit boards are stacked along the axial direction of the probe, and the probe is inserted into the hole.

[0006] Preferably, the diameter of the probe is greater than or equal to 3 mm, and there is a gap between the probe and the edge of the hole.

[0007] Preferably, a plurality of the printed circuit boards are stacked closely together.

[0008] Preferably, there is an insulating medium between the plurality of printed circuit boards.

[0009] Preferably, the insulating medium is plastic, mica or air.

[0010] Preferably, the tangent value of the probe's tilt angle is equal to the diameter difference between the probe and the hole divided by the thickness of multiple stacked printed circuit boards.

[0011] Preferably, the probe inclination angle is 0.

[0012] Preferably, the number of the printed circuit boards is greater than or equal to 2.

[0013] Preferably, the thickness of the printed circuit board is 1.6 mm.

[0014] The advantages provided by the utility model are:

[0015] The utility model stacks a plurality of printed circuit boards, aligns the mounting holes on each printed circuit board, and places the probe in the hole. When the probe is skewed, the skew angle is θ, tanθ=L / (nb), wherein n is the number of printed circuit boards, and n≥2. The thickness of the printed circuit boards can be equivalently increased by stacking the printed circuit boards. When n printed circuit boards are used for stacking, the tangent value can be reduced to 1 / n of the original value, thereby reducing the skew angle of the probe in the hole, thereby improving the verticality of the probe when it is installed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of an existing probe being mounted on a single printed circuit board in an ideal state without tilting;

[0017] Figure 2 A schematic diagram of an existing probe being mounted on a single printed circuit board and tilted in an ideal state;

[0018] Figure 3 A partial schematic diagram of an existing probe being installed on a single printed circuit board and tilted in an ideal state;

[0019] Figure 4 This is a schematic diagram of the probe provided by the utility model being installed on multiple printed circuit boards in an approximately vertical state. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the utility model more clear, the technical solution of the utility model is clearly and completely described below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, but not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] In the actual work of power module testing, the existing connection method is to connect the electrical interface of the test equipment to a specific printed circuit board, and then the spring probe installed on the printed circuit board is electrically connected to the device under test, and then the device under test 3 is tested. In the existing connection method, since a single printed circuit board is used for connection, according to the current industry standards, the maximum thickness of a single printed circuit board can only be 2.0 mm, and the commonly used thickness is 1.6 mm. Considering that there are manufacturing tolerance problems between the probe and the hole position of the printed circuit board, it is impossible for the probe and the hole position on the printed circuit board to be installed together perfectly, which leads to the situation that the probe is easily skewed when installed on the printed circuit board, which in turn affects the effective testing of the device under test, resulting in problems such as difficulty in assembling the power module, low quality, and high rework rate.

[0022] See also Figure 1-2 , assuming that the diameter of the probe 1 is d, the diameter of the hole 21 on the printed circuit board 2 for mounting the probe is D, the gap L between the probe 1 and the hole 21 caused by the manufacturing tolerance is L=Dd, the thickness of the printed circuit board 2 is b, and this embodiment is described by taking the mounting hole 21 on the printed circuit board 2 as a round hole. Figure 1 The probe 1 shown in the figure is not skewed during installation, that is, when it is vertically installed in the hole 21, the central axis of the probe 1 completely coincides with the central axis of the hole 21, and the distance between the edge of the probe 1 and the edge of the hole 21 is L / 2. However, in actual work, due to the existence of the gap between the probe 1 and the hole 21, it is very likely that the probe 1 will be skewed in the hole 21. Figure 2 The status shown, see Figure 3 , assuming that when the probe 1 is skewed in the hole 21, the contact points of the probe 1 and the hole 21 are A and B respectively, the contact point between the lower edge of the probe 1 and the hole 21 is set to A, and the contact point between the upper edge of the probe 1 and the hole 21 is set to B. At this time, the angle at which the probe 1 is skewed is a, tana=L / b, where L is the gap between the probe 1 and the hole 21, and b is the thickness of the printed circuit board 2. When the tangent value tana is larger, the angle a at which the probe 1 is skewed will be larger, such as Figure 4 As shown, the utility model stacks a plurality of printed circuit boards 2, aligns the mounting holes 21 on each printed circuit board 2, and places the probe 1 in the hole 21. When the probe 1 is skewed, the skew angle is θ, tanθ=L / (nb), wherein n is the number of printed circuit boards, n≥2, when n is 2, tanθ=L / (2b), when n is 3, tanθ=L / (3b), and so on. It can be seen that the thickness of the printed circuit boards can be equivalently increased by stacking the printed circuit boards. When n printed circuit boards are used for stacking, the tangent value can be reduced to the original 1 / n, thereby reducing the skew angle of the probe 1 in the hole 21, thereby improving the verticality of the probe during installation.

[0023] The utility model provides a probe fixing structure stacked by multiple printed circuit boards, including multiple printed circuit boards 2, each of which has a hole 21. The multiple printed circuit boards 2 are stacked along the axial direction of a probe 1, and the probe 1 is inserted into the hole 21.

[0024] The diameter of the probe 1 is greater than or equal to 3 mm, and there is a certain gap between the probe 1 and the edge of the hole 21 .

[0025] When multiple printed circuit boards 2 are stacked along the axial direction of the probe 1, the multiple printed circuit boards 2 can be stacked closely, or an insulating medium can be added between the multiple printed circuit boards 2 to separate the multiple printed circuit boards 2. The insulating medium can be plastic, mica or air.

[0026] When the probe 1 is tilted in the hole 21, the tangent value of the tilt angle of the probe 1 is equal to the diameter difference between the probe 1 and the hole 21 divided by the thickness of the stacked printed circuit boards 2. By increasing the number of printed circuit boards or increasing the thickness of the insulating medium between the printed circuit boards, the verticality between the probe and the printed circuit board can be improved at a low cost. When the number of printed circuit boards 2 is set reasonably, the tilt angle of the probe 1 is approximately 0, that is, the probe 1 is vertically inserted into the hole 21.

[0027] The number of the printed circuit boards 2 is greater than or equal to 2. The thickness of the printed circuit boards 2 is 1.6 mm.

[0028] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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 embodiments of the present invention.

Claims

1. A probe fixing structure composed of a plurality of stacked printed circuit boards, characterized in that: The invention comprises a plurality of printed circuit boards, each of which has holes. The plurality of printed circuit boards are stacked along the axial direction of the probe, and the probe is inserted into the hole. The tangent value of the probe inclination angle is equal to the diameter difference between the probe and the hole divided by the thickness of the stacked printed circuit boards.

2. The probe fixing structure composed of a plurality of stacked printed circuit boards according to claim 1, characterized in that: The diameter of the probe is greater than or equal to 3 mm, and there is a gap between the probe and the edge of the hole.

3. The probe fixing structure composed of a plurality of stacked printed circuit boards according to claim 1, characterized in that: A plurality of the printed circuit boards are stacked closely together.

4. The probe fixing structure composed of a plurality of stacked printed circuit boards according to claim 1, characterized in that: There is an insulating medium between the plurality of printed circuit boards.

5. The probe fixing structure composed of a plurality of stacked printed circuit boards according to claim 4, characterized in that: The insulating medium is plastic, mica or air.

6. The probe fixing structure of a plurality of stacked printed circuit boards according to claim 1, characterized in that: The probe inclination angle is 0.

7. The probe fixing structure of a plurality of stacked printed circuit boards according to claim 1, characterized in that: The number of the printed circuit boards is greater than or equal to 2.

8. The probe fixing structure composed of a plurality of stacked printed circuit boards according to claim 1, characterized in that: The thickness of the printed circuit board is 1.6 mm.

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