PCB 2D Code Reading via Residual Copper Rate Control
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Solution Overview
Problem
Conventional printed wiring boards with two-dimensional codes face reading errors due to the reflection of degas patterns from the conductor layer, which can lead to incomplete or inaccurate data retrieval, especially when using ring lighting for QR code reading.
Innovation Solution
A printed wiring board design featuring a conductor layer with a residual copper rate of 80% or more, where the two-dimensional code is formed by exposing portions of the conductor layer through openings in the solder resist layer, ensuring that the degas pattern is not reflected in the code, allowing for accurate reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the conductor layer is used to form the two-dimensional code structure, then the code can be integrated into the wiring board structure, but the degas pattern reflects onto the code causing reading errors
Solution Approach 1:
The patent applies local quality by creating a specific region in the conductor layer with different properties from the surrounding areas. The code formation region has a residual copper rate of 80% or more, while other regions maintain normal conductor layer density. This local differentiation ensures that the code area does not reflect degas patterns, solving the reading accuracy problem while maintaining integration with the wiring board structure.
Solution Approach 2:
The patent changes the physical parameter of the conductor layer by controlling the residual copper rate to be 80% or more in the code formation region. This parameter change modifies the optical properties of the conductor layer, preventing degas pattern reflection and enabling accurate 2D code reading while keeping the code integrated into the board structure.
2Measurement precision
If the residual copper rate in the conductor layer is increased to prevent degas pattern reflection, then code reading accuracy improves, but the conductor layer may become less effective for electrical conduction
Solution Approach 1:
The patent applies local quality by creating a specific region in the conductor layer with different properties from the surrounding areas. The code formation region has a residual copper rate of 80% or more, while other regions maintain normal conductor layer density. This local differentiation ensures that the code area does not reflect degas patterns, solving the reading accuracy problem while maintaining integration with the wiring board structure.
Solution Approach 2:
The patent segments the conductor layer into two distinct functional regions: one region with high residual copper rate (80% or more) optimized for 2D code formation and reading accuracy, and another region with normal conductor layer density optimized for electrical conduction. This segmentation allows each region to perform its specific function effectively without compromising the other.
Data Source
AI summary
A printed wiring board includes a lower layer including conductor layers and insulating layers, a conductor layer formed on the outermost insulating layer in the lower layer, and a solder resist layer formed on the conductor layer such that the solder resist layer is covering the conductor layer on the outermost insulating layer, and a two-dimensional code structure formed on the lower layer and including the conductor layer and a portion of the solder resist layer such that the portion of the solder resist layer has openings forming exposed portions of the conductor layer and that the openings of the solder resist layer and the exposed portions of the conductor layer form the two-dimensional code structure. The conductor layer includes a portion corresponding to the two-dimensional code structure such that the portion of the conductor layer has a residual copper rate that allows the two-dimensional code structure to be read.