Adjustable PCB Test Fixture Probe Density
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Solution Overview
Problem
Conventional PCB test fixtures have limitations in probe density due to fixed distances between probes, leading to incomplete testing and incorrect results, and frequent damage and wear-out of probes from excessive movement, resulting in high replacement costs.
Innovation Solution
A PCB test fixture with adjustable probe density using a substrate, lower and upper electrodes, insulation layers, and conductive cones that allow for selective power transmission to test points, eliminating the need for tilting probes and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the distance between adjacent probes is reduced to increase probe density, then more test points can be covered, but probes may contact each other causing short-circuits
Solution Approach 1:
The probe array is segmented into multiple independently controllable groups or rows. The control system can selectively activate only the probes that need to contact the PCB test points, while keeping other probes retracted or inactive. This segmentation allows high-density probe arrangement without increasing short-circuit risk, as individual probe control prevents simultaneous contact of all probes.
Solution Approach 2:
The probe positions are made dynamically adjustable rather than fixed. The system can dynamically control probe extension/retraction states and positions based on the specific PCB being tested. This dynamic capability allows probes to be positioned precisely for contact with test points while maintaining safety distances when not in use, resolving the contradiction between high density and short-circuit prevention.
2Adaptability or versatility
If stretchable probes are used to accommodate PCB variations, then testing flexibility is improved, but probe damage and wear-out increase due to excessive movement
Solution Approach 1:
The mechanical stretchable probe system is replaced with a controlled positioning system. Instead of relying on probe elasticity and physical stretching to accommodate PCB variations, the system uses precise mechanical or electromagnetic positioning mechanisms to place probes accurately. This substitution eliminates excessive probe movement and stretching, significantly reducing wear and extending probe lifespan while maintaining testing flexibility through programmable positioning.
Solution Approach 2:
The system changes the operational parameters of probes from static fixed positions to dynamically adjustable positions. By controlling probe extension lengths, contact pressures, and positions based on real-time feedback and pre-programmed parameters, the system achieves adaptability without requiring excessive probe movement. This parameter control reduces mechanical stress on probes, preventing damage and extending service life.
3Ease of manufacture
If fixed-distance probe arrangement is used, then manufacturing is simplified, but testing completeness deteriorates due to insufficient probe density
Solution Approach 1:
The test fixture is designed with universal, reconfigurable probe arrays that can be programmed for different PCB layouts and test requirements. Instead of manufacturing dedicated fixtures for each PCB type, a single universal fixture with adjustable probe positions and selective activation capabilities serves multiple functions. This universality maintains manufacturing simplicity while achieving complete test point coverage through software-controlled probe positioning and selection.
Solution Approach 2:
The fixture transitions from a static fixed probe arrangement to a dynamic reconfigurable system. Probe positions, activation states, and contact forces can be dynamically adjusted based on the specific PCB being tested. This dynamic capability allows the same fixture to accurately accommodate various PCB designs and test point densities without compromising manufacturing simplicity, as the reconfiguration is achieved through controlled adjustment mechanisms rather than custom manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution increases probe density, simplifies testing, reduces costs, and extends probe lifespan by allowing high-density electrical testing without the need for frequent replacements, while maintaining compatibility with current PCB fabrication techniques.
Implementation Method 1
The multiple conductive cones are formed on the second insulation layer and are adapted to electrically contact a PCB to be tested. A part of the multiple conductive cones is electrically connected to the respective at least one second connection member.
Data Source
AI summary
A printed circuit board (PCB) test fixture includes a substrate, a first insulation layer formed on the substrate, a conductor layer formed on the first insulation layer and electrically connected to the upper electrodes through at least one first connection member, a second insulation layer formed on the first insulation layer, and multiple conductive cones arranged on the second insulation layer in a matrix form. A part of the conductive cones is electrically connected to the conductor layer through at least one second connection member. The circuit layout of the conductor layer, the at least one first connection member and the at least one second connection member is employed to supply testing power to a part of the conductive cones and an adjustable arrangement of the conductive cones to enhance density of test probes upon electrical testing.