Inspection Unit with Conductive Plating for Impedance Control
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Solution Overview
Problem
The existing inspection units for high-frequency/high-speed devices face challenges in maintaining reliable connections and regulating impedance, especially when contact probes are arranged at a narrow pitch, leading to increased production costs and potential noise interference.
Innovation Solution
An inspection unit featuring an insulative block with conductive plating layers on its surface and through holes, allowing for the use of coaxial contact probes with a gap between the tubular body and inner face, reducing the need for metal blocks and enabling larger probe diameters for power supply contacts without short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal block is used to form through holes for contact probes, then impedance regulation and noise isolation are improved, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The patent uses a composite structure combining an insulative block material with conductive plating layers. The insulative block provides structural support and electrical isolation, while the conductive plating layers on the surface and through-hole inner walls provide the necessary electrical connectivity and impedance regulation. This composite approach replaces the conventional solid metal block, achieving similar electrical performance while enabling more economical manufacturing processes.
Solution Approach 2:
The patent extracts the conductive function from the bulk metal block and applies it selectively as thin plating layers only where needed - on the outer surface and inner walls of through holes. This extraction reduces material usage and manufacturing complexity while maintaining the essential impedance regulation function, making the structure more manufacturable without sacrificing electrical performance.
2Productivity
If through holes are formed at narrow pitch (0.4 to 1 mm) in a metal block, then contact probe arrangement is improved, but manufacturing accuracy requirements increase to ±10 μm
Solution Approach 1:
The insulative block material allows for more flexible manufacturing of narrow-pitch through holes compared to metal blocks. The through holes can be formed using standard drilling or punching techniques on the insulative material, which tolerates tighter pitch requirements without demanding ±10 μm precision. The conductive plating is then applied to the formed holes, accommodating the narrow pitch arrangement of contact probes while reducing manufacturing precision requirements.
3Ease of manufacture
If an insulative block with conductive plating is used instead of a metal block, then manufacturing cost is reduced, but noise isolation capability may be compromised
Solution Approach 1:
The insulative block provides physical structure and electrical isolation, while the conductive plating layers restore the necessary electrical shielding and noise isolation capabilities. The plating layers on the outer surface and through-hole walls create conductive paths that maintain electromagnetic shielding effectiveness, compensating for the insulative nature of the base material and preventing noise intrusion.
Solution Approach 2:
The conductive plating is applied locally only where electrical connectivity and shielding are needed - specifically on the outer surface and inner walls of through holes that accommodate contact probes. This localized application of conductive material provides noise isolation and impedance regulation precisely at the critical interfaces, while the insulative bulk material provides structural support and general electrical isolation elsewhere in the structure.
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
This configuration allows for cost-effective production and high-performance impedance regulation, maintaining noise isolation and contact resistance quality comparable to metal block systems while reducing manufacturing complexity and costs.
Implementation Method 1
Each of the contact probes 63 for RF signals is formed in a coaxial structure, using the contact probe as a core conductor and using an inner wall of a through hole in the metal block 61 as an outer conductor, especially for preventing intrusion of noises
Implementation Method 2
one end of the plunger being adapted to be projected to the exterior by the spring and contracted when pushed
Data Source
AI summary
An insulative block has a first face adapted to oppose a board on which an inspection circuit is arranged and a second face adapted to oppose a device to be inspected. The insulative block is formed with first through holes each of which communicates the first face and the second face. A conductive first plating layer is formed on the first face, the second face, and an inner face of at least one of the first through holes. Each of contact probes includes a conductive tubular body held in an associated one of the first through holes and a plunger which is retractably projected from one end of the tubular body and is adapted to come in contact with a terminal of the device.