A test fixture and a test method
By designing a test fixture that includes a base, a pressing mechanism, and a probe module, the problems of long customization cycles and difficult changeovers for circuit board test fixtures have been solved, enabling efficient, reliable, and universal circuit board testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KOSTAL SHANGHAI ELECTROMECHANICAL CO LTD
- Filing Date
- 2026-03-26
- Publication Date
- 2026-06-12
Smart Images
Figure CN122193874A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of circuit board testing technology, and more particularly to a testing fixture and testing method. Background Technology
[0002] With the rapid development of electronic technology, circuit boards, as core components of electronic devices, are becoming increasingly complex and highly integrated. To ensure that the soldering quality and electrical performance of components on the circuit board meet design requirements, electrical tests such as level detection and signal measurement are typically performed on key test points during the manufacturing process to verify the product's functionality and reliability. Currently, electrical testing of circuit boards mainly relies on two methods: the first is point-by-point measurement by hand-held probes, which suffers from low measurement efficiency, poor contact consistency, and a significant impact on the reliability of the board under test; the second is testing using dedicated test fixtures. While these fixtures improve testing efficiency and reliability compared to hand-held probe testing, they require custom-made fixtures for circuit board redesigns or product model changes, leading to resource waste and inconsistencies in production.
[0003] Improving the versatility of circuit board test fixtures and simplifying changeover operations are technical problems that need to be solved by those skilled in the art. Summary of the Invention
[0004] This invention provides a test fixture and a test method to at least solve the problems of long customization cycles and difficulty in changing designs of dedicated test fixtures for circuit boards in related technologies.
[0005] To solve the above-mentioned technical problems, the present invention provides a test fixture, comprising: a base, a pressing mechanism, and a probe module; The probe module includes a probe substrate, an operating mechanism, and a plurality of probes disposed on the probe substrate. Each probe has at least one initial state retracted from the probe substrate and at least one working state extended from the probe substrate. The operating mechanism is used to control the probes to switch positions. The pressing mechanism is used to press the probe substrate onto the circuit board under test placed on the base, so that the test end of the probe in the working state on the probe substrate contacts the test point of the circuit board under test.
[0006] Optionally, the operating mechanism includes a first operating mechanism and a second operating mechanism; The first operating mechanism is used to control the probe to move in a first direction on the probe substrate to adapt to the horizontal position of the test point on the circuit board under test; the second operating mechanism is used to control the probe to move in a second direction on the probe substrate to adapt to the height of the test point protruding from the circuit board under test.
[0007] Optionally, the first operating mechanism includes a first translation component and a second translation component; The first translation component is movably disposed on the probe substrate, and the direction of movement of the first translation component is a third direction; The second translation component is movably disposed on the first translation component, and the direction of movement of the second translation component is the fourth direction; The third direction intersects with the fourth direction, and one of the second translation components is provided with at least one of the probes.
[0008] Optionally, the second operating mechanism includes a state switching component, which is connected to the probe drive. The state switching component has at least two stable operating positions; When the state switching component is in the first working position, the probe is in the initial state; When the state switching component is in the second working position, the probe is in the working state; Furthermore, the state switching component is configured to cycle between the first working position and the second working position in response to continuous pressing operations.
[0009] Optionally, the base is provided with a positioning component, the positioning component having a positioning part adapted to the positioning reference part on the circuit board under test; The pressing mechanism is movably disposed on the base. When the pressing mechanism is in the open state, it is used to pick up and place the circuit board under test onto the base. When the pressing mechanism is in the closed state, it is used to fix the probe module at a predetermined test position on the upper part of the positioning component.
[0010] Optionally, a test interface is also included; The test interface has several pins, which are used to transmit test signals from the probe.
[0011] Optionally, the probe is connected to the test interface via a first circuit, the first circuit including a first resistor, an overvoltage protection element, and a signal configuration circuit; Wherein, the first resistor is connected between the probe and the first circuit node of the first circuit; the overvoltage protection element is connected between the first circuit node and ground; The signal configuration circuit includes an analog test channel, a digital test channel, and a channel switching module. The first end of the analog test channel and the first end of the digital test channel are connected to the common terminal of the signal configuration circuit. The second end of the analog test channel and the second end of the digital test channel are respectively connected to the first output terminal and the second output terminal of the signal configuration circuit. The channel switching module is used to control the common terminal to be connected to the first output terminal or the common terminal to be connected to the second output terminal in response to a mode selection command.
[0012] Optionally, a controller may also be included; The controller is used to control the extension and retraction state of the probe based on the test point location information of the circuit board under test.
[0013] Optionally, the controller is specifically used for: Identify the circuit board file of the circuit board under test to obtain the location information of the test points; Based on the test point location information and the number of probes, the test partition of the circuit board under test and the test point location information of the test partition are determined. During the testing of the circuit board under test, the extension and retraction states of the probes in the probe module are configured according to the partition test point information of the current test partition.
[0014] To address the aforementioned technical problems, the present invention also provides a testing method, comprising: a testing fixture based on any one of the above-described methods, comprising: Determine the location information of the test points on the circuit board under test; The probe extension and retraction states of the probe module in the test fixture are controlled according to the test point location information, so that the probe corresponding to the test point of the circuit board under test is in the working state, and the probe not corresponding to the test point of the circuit board under test is in the initial state.
[0015] This invention provides a test fixture comprising a base, a pressing mechanism, and a probe module. The probe module includes a probe substrate, an operating mechanism, and multiple probes disposed on the probe substrate. Each probe has at least one initial state retracted from the probe substrate and at least one working state extended from the probe substrate. The operating mechanism controls the position switching of the probes. The pressing mechanism presses the probe substrate onto the circuit board under test placed on the base, so that the test ends of the working probes on the probe substrate contact the test points of the circuit board under test. When testing the circuit board under test using this test fixture, the extension and retraction states of the probes on the probe module can be configured according to the test point positions of the circuit board under test, forming a dedicated test mode for the circuit board under test. This achieves high-efficiency and high-reliability testing of the circuit board while also possessing the advantages of high versatility and easy replacement. Attached Figure Description
[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a top view of a test fixture provided in an embodiment of the present invention; Figure 2 An exploded view of a test fixture provided in an embodiment of the present invention; Figure 3 A silkscreen diagram of a test interface provided in an embodiment of the present invention; Figure 4 A schematic diagram of the structure of an operating mechanism provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a probe array for a probe module provided in an embodiment of the present invention; Figure 6 A circuit diagram of a first circuit provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a calibration carrier plate provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the test process and timing of a test method provided in an embodiment of the present invention.
[0018] Figure label: 100-Base, 101-Positioning component, 200-Probe module, 201-Probe substrate, 202-Probe, 203-First translation component, 204-Second translation component, 205-State switching component, 206-Third translation component, 207-Travel limit ring, 300-Wire harness, 400-Pressure mechanism, 500-Circuit board under test, 600-Test interface, 700-Grounding and shielding structure, 800-Calibration carrier board. Detailed Implementation
[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.
[0020] It should be noted that, in the description of this invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. The terms "first," "second," etc., used in this invention are used to distinguish similar objects and are not used to describe a specific order or sequence.
[0021] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0022] Figure 1 This is a schematic diagram of the structure of a test fixture provided in an embodiment of the present invention; Figure 2 This is an exploded view of a test fixture provided in an embodiment of the present invention.
[0023] like Figure 1 As shown, the test fixture provided in this embodiment of the invention may include: a base 100, a pressing mechanism 400, and a probe module 200; wherein, the probe module 200 includes a probe substrate 201, an operating mechanism, and a plurality of probes 202 disposed on the probe substrate 201, the probes 202 having at least one initial state retracted from the probe substrate 201 and at least one working state extended from the probe substrate 201, the operating mechanism being used to control the probes 202 to switch positions; the pressing mechanism 400 being used to press the probe substrate 201 onto the circuit board 500 under test placed on the base 100, so that the test ends of the probes 202 in the working state on the probe substrate 201 contact the test points of the circuit board 500 under test.
[0024] The test fixture provided in this embodiment of the invention can be used to perform electrical tests such as level detection and signal measurement on printed circuit boards (PCBs).
[0025] like Figure 1 As shown, the base 100 is used to place the circuit board 500 under test. The pressing mechanism 400 is connected to the base 100 and is used to drive the probe 202 of the probe module 200 to extend one side and press it onto the circuit board 500 under test. The other end of the probe 202 is connected to the test interface 600 through the wire harness 300 to connect to external test instruments (such as oscilloscope, multiplexer, analog-to-digital converter + microcontroller) to realize threshold determination, upper computer communication and light board indication.
[0026] In this embodiment of the invention, the base 100 may be provided with a positioning component 101, which has a positioning portion adapted to the positioning reference portion on the circuit board 500 under test. A pressing mechanism 400 is movably disposed on the base 100. When the pressing mechanism 400 is in the open state, it is used to place the circuit board 500 under test onto the base 100. When the pressing mechanism 400 is in the closed state, it is used to fix the probe module 200 at a predetermined test position on the upper part of the positioning component 101.
[0027] In practical implementation, the base 100 can adopt a frame structure assembled from aluminum profiles or steel plates to achieve good rigidity and flatness. The panel of the base 100 is provided with multiple positioning pin holes and side adjustment grooves.
[0028] The positioning component 101 is used to pre-position the circuit board 500 under test. In this embodiment of the invention, the positioning component 101 can adopt a "two-hole, one-positioning-edge" reference scheme, specifically including: positioning posts (two can be provided), which are adapted to the mechanical reference holes on the circuit board 500 under test to achieve precise hole positioning; adjustable edge stops, which are provided along the edge of the base 100 and are adapted to the outer reference edge of the circuit board 500 under test. The adjustable edge stops can be slidably installed in the adjustment groove of the base 100, and can be moved in a direction perpendicular to the corresponding edge by adjusting screws. The adjustment range can be within ±3mm, which is used to compensate for the processing tolerance of the circuit board edge; elastic limiting members, which can be elastic side clamps, are provided on the side of the positioning component 101 to provide lateral holding force after the circuit board 500 under test is placed, preventing its displacement. As an alternative, the elastic limiting members can also be vacuum adsorption holes provided on the surface of the base 100, which fix the circuit board 500 under test by negative pressure adsorption.
[0029] The pressing mechanism 400 is movably connected to the base 100 and has an open state and a closed state. The pressing mechanism 400 may include a driving unit and a clamping unit, the driving unit being used to provide driving force and the clamping unit being used to apply a uniform holding force to the circuit board 500 under test in the closed state.
[0030] In some optional embodiments of the present invention, the pressing mechanism 400 adopts an upper-mounted flip-top structure. The driving unit includes a flip-top connecting rod and a toggle lock. One end of the flip-top connecting rod is pivotally connected to one side of the base 100, and the pressing unit is mounted on the other end of the flip-top connecting rod. The toggle lock is located on the other side of the base 100 and is used to lock the flip-top connecting rod to the base 100 when the flip-top is closed. The operator applies a pressing force by pressing down the flip-top and locking the toggle. In this structure, the flip-top connecting rod constitutes the main frame of the driving unit, and its movement trajectory is an arc-shaped path around the pivot axis. The maximum pressing stroke of the pressing mechanism 400 can be designed to be 15~25mm.
[0031] In some optional embodiments of the present invention, the pressing mechanism 400 may also adopt a horizontal pressing structure, that is, the driving unit drives the pressing unit to move linearly in a direction perpendicular to the surface of the circuit board 500 under test. The test fixture provided in the present invention may further include a gantry frame mounted above the base 100, with guide holes or guide rails provided on the crossbeams of the gantry frame; the driving unit is mounted on the crossbeams of the gantry frame, and the output end of the driving unit passes through the guide holes or connects to the guide rails, and is connected to the pressing unit in a transmission connection; the pressing unit, driven by the driving unit, moves vertically up and down along the guide holes or guide rails, thereby approaching or moving away from the circuit board 500 under test located on the base 100.
[0032] In this embodiment of the invention, the drive unit can employ a manually driven motion structure, such as a screw drive mechanism, a rack and pinion mechanism, or a quick clamp. Alternatively, the drive unit can employ an automatically driven actuator, such as a pneumatic cylinder, an electric cylinder, or a linear motor.
[0033] The clamping unit may include a pressure plate assembly and pressure heads mounted on the pressure plate assembly. The pressure plate assembly is a rigid plate connected to the output end of the drive unit. Multiple pressure heads may be present, preferably mounted on the pressure plate assembly using an elastic floating connection. The pressure heads are connected to the pressure plate assembly via an elastic element, preferably a balance spring, allowing each pressure head to independently and adaptively adjust its posture during the clamping process. Regarding force limiting, by selecting an elastic element with a suitable elastic coefficient and setting the end point of the drive unit's stroke, the single-point pressing force applied by each pressure head to the surface of the circuit board 500 under test when the clamping mechanism 400 is in the closed state can be controlled between 0.8N and 1.2N. This pressure value can be adaptively adjusted according to the specifications of the probe 202 of the probe module 200 and the degree of metallization of the test points on the circuit board, ensuring reliable contact between the probe 202 and the test points while effectively preventing damage to the components on the circuit board. Therefore, when the pressing mechanism 400 is closed, even if there is slight warping or unevenness on the surface of the circuit board 500 under test, multiple pressure heads can evenly contact and press the edge or blank area of the circuit board, pressing the entire circuit board onto the positioning component 101, thereby providing a stable and defined test plane for the probe module 200.
[0034] Using the base 100, positioning component 101, and pressing mechanism 400 described above, when the pressing mechanism 400 is in the open state, the positioning component 101 is exposed above the base 100, allowing the operator to place the circuit board 500 under test. During placement, the positioning component 101 positions and fixes the circuit board 500 according to a predetermined method, ensuring that the test points on the circuit board 500 are aligned with the probes 202 of the probe module 200. Once the circuit board 500 is in place, the pressing mechanism 400 switches from the open state to the closed state. The pressing mechanism 400 moves the probe module 200 closer to the circuit board 500, causing the probes 202 extending from the lower part of the probe module 200 to contact the test points on the circuit board 500, thus establishing an electrical connection. After the test is completed, the pressing mechanism 400 switches back to the open state, moving the probe module 200 away from the circuit board 500, allowing the operator to remove the circuit board 500 from the base 100.
[0035] In this embodiment of the invention, the probes 202 in the probe module 200 can be selected and configured according to the test point characteristics of the circuit board 500 under test. The probes 202 are mounted on the probe substrate 201, which can employ a grid hole array design with a grid spacing of 2.54 mm or 5 mm. Brass bushings are pressed into each grid hole to improve the repeatability and positioning consistency of the probes 202. The probes 202 can adopt a spring-loaded needle structure with an elastic stroke ranging from 2 to 6 mm to accommodate different thicknesses of the circuit board 500 under test and variations in the spacing between the probe substrate 201 and the circuit board 500. The head shape of the probes 202 can be selected based on the specific shape of the test point on the circuit board 500 under test. For example, for conventional test points, flat-headed or hemispherical-headed probes 202 can be selected; for small test points covered with solder mask, blade-headed or crown-headed probes 202 can be used to pierce the solder mask and achieve reliable contact; for power or ground test points, high-current probes 202 are selected. The electrical performance parameters of probe 202 can be designed to meet the following requirements: rated current greater than 1A, suitable for the current carrying requirements of power supply and ground test points; probe body resistance less than 50mΩ, to ensure the transmission accuracy and stability of test signals.
[0036] The extension and retraction state of probe 202 can be controlled by state switching component 205, which has at least two stable working positions. When state switching component 205 is in the first working position, probe 202 is in the initial state. When state switching component 205 is in the second working position, probe 202 is in the working state. Furthermore, state switching component 205 is configured to cycle between the first working position and the second working position in response to continuous pressing operations.
[0037] In this embodiment of the invention, the state switching component 205 can be controlled manually or electrically, depending on the testing requirements and application scenario.
[0038] In manual control mode, the state switching component 205 can employ a mechanical pressing mechanism. This structure specifically includes a pressing operation element, a guide sleeve, a return spring, and a locking-unlocking conversion element. The pressing operation element can be a pressing rod, with the guide sleeve fixedly mounted on the probe substrate 201. The pressing rod can slide axially through the guide sleeve. The locking-unlocking conversion element includes a guide pin on the outer wall of the pressing rod and an annular ratchet groove connected end-to-end on the inner wall of the guide sleeve, with the guide pin engaging within the ratchet groove. The return spring is sleeved on the pressing rod to provide the reset driving force. During operation, the operator manually presses the pressing rod, which moves downwards against the spring force of the return spring, and the guide pin slides along the guide slope of the ratchet groove. When the pressing reaches the end of the first stroke and is released, the guide pin, under the action of the return spring, engages in the first locked position of the ratchet groove. At this time, the state switching component 205 is in a first stable state, and the probe 202, which is connected to it, remains extended beyond the probe substrate 201. Pressing the lever again disengages the guide pin from the first locking position and slides along the ratchet groove to the second end of the stroke. After release, the guide pin engages in the second locking position of the ratchet groove, and the state switching component 205 switches to the second stable state, causing the probe 202 to retract to the retracted probe substrate 201 state. Thus, through continuous pressing operations, the probe 202 can be cyclically switched between the extended and retracted states.
[0039] In the electric control mode, the state switching component 205 can employ an electrically controlled drive mechanism, which specifically includes a drive element, a transmission element, and a probe 202 controller. In some optional embodiments, the drive element is a linear motion electromagnet or a micro motor. For example, the drive element can be a push-pull electromagnet with a retractable output shaft, and the transmission element is connected between the output shaft and the probe 202 to transmit the linear motion of the output shaft to the probe 202. The probe controller is electrically connected to the drive element and is used to control the timing of the drive element's operation. During operation, after receiving an external trigger signal (e.g., a test start command from a host computer or a button signal from the operation panel), the probe controller outputs a first control signal to the drive element, energizing it and causing its output shaft to extend or retract. This, in turn, drives the probe 202 to switch to the extended state via the transmission element and maintains it in that state. When the test is completed or the controller receives the next trigger signal, the probe controller outputs a second control signal to the drive element, causing the drive element to reverse its operation or de-energize and reset, in which case the probe 202 retracts to the retracted state via the transmission element.
[0040] In other alternative implementations, the driving element can also be a stepper motor in conjunction with a lead screw and nut mechanism. By controlling the rotation angle and direction of the motor, the extension and retraction of the probe 202 can be precisely controlled. The controller controls the forward, reverse, and stop positions of the motor according to a preset program or real-time commands, thereby achieving automatic switching of the probe 202's state.
[0041] In electric control mode, the state switching component 205 can also integrate a position sensor to detect the current position of the probe 202 and feed the detection signal back to the probe controller to form closed-loop control, thereby improving the reliability and accuracy of state switching.
[0042] The test fixture provided in this embodiment of the invention may further include a test interface 600; the test interface 600 has several pins, which are used to transmit test signals from the probe 202. The test interface 600 may be a D-subminiature connector (DB, where the number following it indicates the number of pins), and the number of pins of the test interface 600 is selected according to the number of signals, signal type, and spatial structure of the test points on the circuit board under test 500. For example, for a small number of low-speed signals, DB9 or DB15 can be selected. For standard digital I / O, DB25 can be selected. For mixed signals, DB37 can be selected. For multi-channel analog acquisition, multiple test interfaces 600 can be configured.
[0043] like Figure 2 As shown, each probe 202 is connected to the identification sleeve via an independent wire to form a wire bundle 300, which is then connected to the test interface 600.
[0044] Figure 3 This is a silkscreen diagram of a test interface provided in an embodiment of the present invention. Figure 3 As shown, the test interface 600 can be labeled with corresponding pins to facilitate the matching of pins with probes 202. The wire harness 300 end can also be equipped with a foolproof structure.
[0045] The 300 wire harness can use 26–28 AWG stranded wire, with individual color / heat shrink markings for each channel, all integrated into the sheath. The D-type miniature connector male has a screw-locking mechanism, and the outer shell is grounded at the same potential as the fixture housing.
[0046] The mapping between probe 202 and the pins on test interface 600 can be recorded in a storage device for management, or recorded on the corresponding identification plate of the test fixture. For example, when using DB37, the mapping cards for test channels CH1~CH37 and DB37 pins 1~37 can be fixed or replaceable; for example, CH1→DB37-1, CH2→DB37-2…CH37→DB37-37. This can be clearly marked on the nameplate of the test fixture. If the model of the circuit board under test 500 needs to be changed, after reconstructing the extension / retraction state of probe 202, the nameplate of the test fixture should be replaced to update to the new mapping state.
[0047] The test fixture can also record its corresponding circuit board model, probe 202 coordinates, test interface 600 mapping version and maintenance records via QR code or RFID.
[0048] like Figure 1 As shown, the test fixture provided in this embodiment of the invention may further include a grounding and shielding structure 700 disposed on the base 100 to reduce noise coupling. The grounding system adopts a design that separates the chassis ground and signal ground, including a dedicated chassis ground probe and a dedicated signal ground probe. The two are kept connected at a single point or completely isolated inside the test fixture to avoid forming a ground loop. The shielding structure includes a shielding cover disposed around the probe module 200. The shielding cover is made of conductive plastic or metal mesh and is connected to the base 100 through a single-point grounding method. For test points with high impedance or weak analog signals, the signal transmission path adopts a coaxial lead structure. The tail end of the probe 202 is connected to the inner core of the coaxial cable, and the outer shielding layer is grounded nearby, and the suspended length of the inner core is shortened as much as possible to achieve continuous shielding from the test point to the test interface 600.
[0049] Based on the above embodiments, the present invention further describes the operating mechanism.
[0050] In this embodiment of the invention, the operating mechanism may include a first operating mechanism and a second operating mechanism; the first operating mechanism is used to control the probe 202 to move in a first direction of the probe substrate 201 to adapt to the horizontal position of the test point on the circuit board 500 under test; the second operating mechanism is used to control the probe 202 to move in a second direction of the probe substrate 201 to adapt to the height of the test point protruding from the circuit board 500 under test.
[0051] Specifically, the first direction can be any direction horizontal to the probe substrate 201, and the second direction is a direction perpendicular to the probe substrate 201.
[0052] Figure 4 This is a schematic diagram of an operating mechanism provided in an embodiment of the present invention.
[0053] In specific implementation, such as Figure 4As shown, the first operating mechanism may include a first translation component 203 and a second translation component 204; the first translation component 203 is movably disposed on the probe substrate 201, and the movement direction of the first translation component 203 is a third direction; the second translation component 204 is movably disposed on the first translation component 203, and the movement direction of the second translation component 204 is a fourth direction; the third direction intersects with the fourth direction, and each second translation component 204 is provided with at least one probe 202.
[0054] In a specific implementation, the first translation component 203 may include a first translation seat and a first drive component. The first translation seat is connected to the first drive component. The first drive component includes a first adjusting screw and a first guide rail. By rotating the first adjusting screw, the first translation seat is driven to reciprocate along the first guide rail in a third direction.
[0055] The second translation component 204 may include a second translation seat and a second drive component. The second translation seat is disposed on the first translation seat and can move together with the first translation seat. The sliding direction of the second translation seat is a fourth direction, which intersects with a third direction and can be perpendicular to each other (X-axis direction, Y-axis direction). The second translation seat is connected to the second drive component, which may include a second adjusting screw and a second guide rail. By rotating the second adjusting screw, the second translation seat is driven to reciprocate along the second guide rail in the second direction.
[0056] The second operating mechanism can be installed on the second translation seat, and the probe 202 is installed on the second operating mechanism. By adjusting the positions of the first translation seat and the second translation seat, the probe module 200 can be accurately positioned in a two-dimensional plane.
[0057] In some alternative implementations, the first and second drive components may also be electrically driven, such as a stepper motor in conjunction with a lead screw and nut mechanism, with automatic alignment achieved through a controller.
[0058] In this embodiment of the invention, the second operating mechanism may include a state switching component 205, which is drively connected to the probe 202. The state switching component 205 has at least two stable working positions. When the state switching component 205 is in the first working position, the probe 202 is in the initial state. When the state switching component 205 is in the second working position, the probe 202 is in the working state. Furthermore, the state switching component 205 is configured to cycle between the first working position and the second working position in response to continuous pressing operations.
[0059] The state switching component 205 can be installed on the second translation seat, and its specific structure can be referred to the description of the above embodiment.
[0060] Furthermore, the second operating mechanism may also include a third translation component 206, which is used to fine-tune the position of the probe 202 in the second direction to accommodate circuit boards 500 of different thicknesses or to control the compression of the probe 202. The third translation component 206 may include a lifting seat and an adjusting member. The lifting seat is slidably mounted on the second translation seat, and the probe 202 is mounted on the lifting seat, with the sliding direction of the lifting seat being the second direction. The adjusting member may be an adjusting screw, one end of which is connected to the lifting seat. By rotating the adjusting member, the lifting seat is driven to make precise lifting and lowering movements in the third direction, thereby achieving fine-tuning of the height of the probe 202.
[0061] The second operating mechanism may further include a travel limit ring 207, which is sleeved on the outside of the lifting seat or disposed between the lifting seat and the second translation seat to limit the range of movement of the lifting seat in the second direction. When the lifting seat moves to the upper limit position or the lower limit position, the travel limit ring 207 abuts against the corresponding surface of the second translation seat, thereby limiting further movement of the lifting seat and preventing over-adjustment that could damage the probe 202 or cause test failure.
[0062] In this embodiment of the invention, the first translation component 203 and the second translation component 204 can provide a travel range of ±1.0 mm centered on the initial installation position of the probe 202, and the third translation component 206 can provide a travel range of 0 to 3 mm.
[0063] Figure 5 This is a schematic diagram of a probe array for a probe module provided in an embodiment of the present invention.
[0064] like Figure 5 As shown, the probe substrate 201 can be divided into a multi-row, multi-column grid with no overlapping areas between the grids, allowing the probe 202 to adjust its position in a first direction within its assigned grid. Figure 5 Taking the first cell in the first row and first column as an example, the probe can move in the first direction of the cell, specifically in the X and Y directions, to adjust the probe's position horizontally on the probe substrate 201. It should be noted that... Figure 5 The movement range shown in the first direction is for illustrative purposes only. In practice, movement ranges of other shapes and sizes can be set.
[0065] Figure 6 A circuit diagram of a first circuit provided for an embodiment of the present invention.
[0066] Based on the above embodiments, such as Figure 6As shown, probe 202 is connected to test interface 600 via a first circuit, which includes a first resistor, an overvoltage protection element, and a signal configuration circuit. The first resistor is connected between probe 202 and a first circuit node of the first circuit. The overvoltage protection element is connected between the first circuit node and ground. The signal configuration circuit includes an analog test channel, a digital test channel, and a channel switching module. The first end of the analog test channel and the first end of the digital test channel are connected to the common terminal of the signal configuration circuit. The second end of the analog test channel and the second end of the digital test channel are respectively connected to the first output terminal and the second output terminal of the signal configuration circuit. The channel switching module is used to control the common terminal to be connected to the first output terminal or the common terminal to be connected to the second output terminal in response to a mode selection command.
[0067] In practical implementation, the first resistor is placed near probe 202 as a current-limiting resistor, and can be a 100~330Ω current-limiting resistor. The overvoltage protection element can be a transient voltage suppressor (TVS), which is used for channel-level electrostatic discharge (ESD) protection and overvoltage protection.
[0068] The signal configuration circuit is used to adapt to the type of test point. For analog test points, it switches to the analog test channel, which can be equipped with a high input impedance buffer module (>1MΩ, Cin<10 pF); for digital test points, it switches to the digital test channel, which can be equipped with a comparator.
[0069] Based on the above embodiments, the test fixture provided in this embodiment of the invention may further include a controller; the controller is used to control the extension and retraction state of the probe 202 according to the test point position information of the circuit board 500 under test.
[0070] In this embodiment of the invention, the controller may be the same as or a different controller from the probe 202 controller in the above embodiments. This controller is at least used to acquire the test point location information of the circuit board 500 under test, and accordingly control the extension and retraction state of the probe 202 on the probe substrate 201. Specifically, the control method can be combined with the electric control methods of the pressing mechanism 400, operating mechanism, etc., described in the above embodiments, whereby the controller sends electric control signals to control the extension and retraction state of the probe 202 and the opening and closing of the pressing mechanism 400. Furthermore, the controller can also control the probe 202 to perform fine adjustments in a first direction and a second direction within its area.
[0071] In practical applications, the area of the circuit board 500 under test varies greatly, and a single probe module 200 may not be able to cover the entire circuit board 500 under test.
[0072] In some optional implementations, the test fixture provided in this embodiment of the invention may include multiple probe modules 200, each probe module 200 being connected to the test interface 600 in a one-to-one correspondence, and multiple probe modules 200 can be used simultaneously to test a circuit board 500 under test.
[0073] In some alternative implementations, the circuit board 500 under test can be divided into multiple test zones, and one or a small number of probe modules 200 can be controlled to move to the corresponding test zones for testing. The controller provided in this embodiment can also be used to: identify the circuit board file of the circuit board 500 under test to obtain test point location information; determine the test zones of the circuit board 500 under test and the test point location information of the test zones based on the test point location information and the number of probes 202; and configure the extension / retraction state of the probes 202 in the probe modules 200 according to the test point information of the current test zone during the testing of the circuit board 500. That is, when the area of the circuit board 500 under test is large, by dividing the circuit board 500 under test into multiple test zones, for each test zone, the controller can first identify the test point location information of the control zone and reconfigure the extension / retraction state of the probes 202 on the probe modules 200, then perform the test on that test zone, and then control the probe modules 200 to move to the next test zone, and so on.
[0074] Figure 7 This is a schematic diagram of a calibration carrier plate provided in an embodiment of the present invention.
[0075] In accordance with the test fixtures provided in the above embodiments, this embodiment of the invention also provides a calibration carrier plate 800, such as... Figure 7 As shown, the calibration carrier board 800 can be implemented using a small circuit board, which includes basic signals such as GND (ground) shorting point, Vref (reference voltage, which can be 1.000V), Vdd / 2 (MCU power supply) voltage divider, and open circuit (verification of high impedance).
[0076] Using calibration carrier board 800, short-circuit some channels of probe module 200 to a known 1,000V reference power supply and GND (ground), and leave some channels floating to verify the threshold and noise margin. Perform regular calibration and maintenance to ensure the reliability of the test fixture's test results; this can be done daily or monthly.
[0077] In addition, a maintenance cycle for probe 202 can be set, for example, replacing probe 202 every 50,000 to 100,000 presses. The test points and probe 202 tip can also be cleaned periodically using anhydrous alcohol and fibrous cotton swabs.
[0078] By establishing quality control standards for probe 202 indentation force, contact resistance, cleaning cycle, and probe life, the reliable working condition of the test fixture can be further maintained.
[0079] In summary, the test fixture provided in this embodiment of the invention can be quickly changed using a hole array or a fine-tuning base to adapt to different circuit board test point layouts. Furthermore, floating pressure heads, force limiting devices, and adjustable strokes ensure uniform multi-point contact between the probe module and the circuit board under test, protecting the board. The test fixture provided in this embodiment of the invention uses a standard test interface (such as DB37) for unified output, facilitating interfacing with oscilloscopes / data acquisition cards / logic analyzers / ATE and Vector System benches. The test fixture provided in this embodiment of the invention also reduces the risk of misconnection and electrostatic damage through the electrostatic discharge protection and overvoltage protection of the channel machine. The test fixture provided in this embodiment of the invention also includes a calibration carrier and mapping markings, improving production line maintainability and quality traceability.
[0080] The various embodiments corresponding to the test fixture have been described in detail above. Based on this, the present invention also discloses test methods, test devices, electronic devices and computer-readable storage media corresponding to the above-mentioned test fixtures.
[0081] This invention provides a testing method that can be implemented based on the testing fixture provided in any of the above embodiments. The testing method may include: determining the test point location information of the circuit board under test; and controlling the extension and retraction state of the probes on the probe module in the testing fixture according to the test point location information, so that the probes corresponding to the test points of the circuit board under test are in the working state, and the probes not corresponding to the test points of the circuit board under test are in the initial state.
[0082] Before using the test fixture, if the test point layout of the circuit board under test is different from the previous test, the test fixture needs to be reconfigured. This process may include: importing the printed circuit board source file (PCB Gerber) or test point list to generate probe coordinates; arranging the corresponding probes on the hole array / fine-tuning seat; adjusting the X, Y, and Z directions to align the probes with the test points and preset the stroke and pressure.
[0083] Figure 8 This is a schematic diagram of the test process and timing of a test method provided in an embodiment of the present invention.
[0084] like Figure 8 As shown, the testing method provided in this embodiment of the invention may include: placing the circuit board: placing the circuit board to be tested inside the positioning component.
[0085] Pressing / Contact Establishment: The closing pressing mechanism establishes stable contact between all probes and their corresponding test points.
[0086] Stabilize / Debouncing: Wait for a period of time to allow the test signal to stabilize and avoid misjudgment.
[0087] Measurement / Sampling: Connects to external test equipment via the test interface, performs channel scanning or parallel judgment, and outputs the level status and voltage value of each test point.
[0088] Judgment / Recording: Record test data or determine results based on thresholds set for test items (such as TTL / CMOS standards). Specifically, output level status and voltage can be determined according to thresholds (e.g., TTL: low <0.8V, high >2.0V; or CMOS depending on the power supply domain). Perform channel-level Pass / Fail determination based on test specifications or hardware circuit calculation tables, and generate records.
[0089] The testing method provided in this embodiment of the invention may further include: reset and maintenance: lift the pressing mechanism to remove the plate, perform contact resistance and probe contamination checks on abnormal channels; periodically use a calibration carrier to verify channel consistency and contact resistance, and replace probes or adjust fine-tuning seats if necessary.
[0090] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.
[0091] The present invention has been described in detail above as a testing fixture and testing method. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are only intended to help understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the present invention.
Claims
1. A test fixture, characterized in that, include: Base, pressing mechanism, and probe module; The probe module includes a probe substrate, an operating mechanism, and a plurality of probes disposed on the probe substrate. Each probe has at least one initial state retracted from the probe substrate and at least one working state extended from the probe substrate. The operating mechanism is used to control the probes to switch positions. The pressing mechanism is used to press the probe substrate onto the circuit board under test placed on the base, so that the test end of the probe in the working state on the probe substrate contacts the test point of the circuit board under test.
2. The test fixture according to claim 1, characterized in that, The operating mechanism includes a first operating mechanism and a second operating mechanism; The first operating mechanism is used to control the probe to move in a first direction on the probe substrate to adapt to the horizontal position of the test point on the circuit board under test; the second operating mechanism is used to control the probe to move in a second direction on the probe substrate to adapt to the height of the test point protruding from the circuit board under test.
3. The test fixture according to claim 2, characterized in that, The first operating mechanism includes a first translation component and a second translation component; The first translation component is movably disposed on the probe substrate, and the direction of movement of the first translation component is a third direction; The second translation component is movably disposed on the first translation component, and the direction of movement of the second translation component is the fourth direction; The third direction intersects with the fourth direction, and one of the second translation components is provided with at least one of the probes.
4. The test fixture according to claim 2, characterized in that, The second operating mechanism includes a state switching component, which is connected to the probe drive. The state switching component has at least two stable operating positions; When the state switching component is in the first working position, the probe is in the initial state; When the state switching component is in the second working position, the probe is in the working state; Furthermore, the state switching component is configured to cycle between the first working position and the second working position in response to continuous pressing operations.
5. The test fixture according to claim 1, characterized in that, The base is provided with a positioning component, which has a positioning part that is adapted to the positioning reference part on the circuit board under test. The pressing mechanism is movably disposed on the base. When the pressing mechanism is in the open state, it is used to pick up and place the circuit board under test onto the base. When the pressing mechanism is in the closed state, it is used to fix the probe module at a predetermined test position on the upper part of the positioning component.
6. The test fixture according to claim 1, characterized in that, It also includes a test interface; The test interface has several pins, which are used to transmit test signals from the probe.
7. The test fixture according to claim 6, characterized in that, The probe is connected to the test interface via a first circuit, which includes a first resistor, an overvoltage protection element, and a signal configuration circuit. Wherein, the first resistor is connected between the probe and the first circuit node of the first circuit; the overvoltage protection element is connected between the first circuit node and ground; The signal configuration circuit includes an analog test channel, a digital test channel, and a channel switching module. The first end of the analog test channel and the first end of the digital test channel are connected to the common terminal of the signal configuration circuit. The second end of the analog test channel and the second end of the digital test channel are respectively connected to the first output terminal and the second output terminal of the signal configuration circuit. The channel switching module is used to control the common terminal to be connected to the first output terminal or the common terminal to be connected to the second output terminal in response to a mode selection command.
8. The test fixture according to claim 1, characterized in that, It also includes the controller; The controller is used to control the extension and retraction state of the probe based on the test point location information of the circuit board under test.
9. The test fixture according to claim 8, characterized in that, The controller is specifically used for: Identify the circuit board file of the circuit board under test to obtain the location information of the test points; Based on the test point location information and the number of probes, the test partition of the circuit board under test and the test point location information of the test partition are determined. During the testing of the circuit board under test, the extension and retraction states of the probes in the probe module are configured according to the partition test point information of the current test partition.
10. A testing method, characterized in that, include: The test fixture based on any one of claims 1 to 9 includes: Determine the location information of the test points on the circuit board under test; The probe extension and retraction states of the probe module in the test fixture are controlled according to the test point location information, so that the probe corresponding to the test point of the circuit board under test is in the working state, and the probe not corresponding to the test point of the circuit board under test is in the initial state.