Circuit Device Soldering Alignment via Selective Resist
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Solution Overview
Problem
Existing methods face challenges in soldering electronic components to pads on three-dimensional circuit devices due to difficulties in applying resist patterns, leading to potential solder flow-out and misalignment of camera units, which affects the performance of image pickup apparatuses.
Innovation Solution
A circuit device design with symmetrically arranged first conductor patterns and a resist pattern covering only the second conductor but not the first, allowing solder to flow out symmetrically and preventing misalignment, facilitated by using a dispenser to apply the resist pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resist pattern is applied to cover all conductor patterns for preventing solder flow-out, then soldering reliability is improved, but manufacturing complexity and resist material usage increase
Solution Approach 1:
The resist pattern is selectively applied only to the second conductor pattern that connects to the central electrode, while leaving the first conductor patterns (connecting to peripheral electrodes) without resist coverage. This local differentiation prevents solder flow-out at the critical central connection while allowing controlled solder flow at peripheral connections, reducing overall resist material usage and pattern complexity.
Solution Approach 2:
The conductor patterns are segmented into two functional groups: first conductor patterns connecting peripheral electrodes and second conductor patterns connecting the central electrode. The resist pattern is then applied selectively to only the second group, creating a differentiated resistance structure that addresses specific soldering requirements of each conductor type.
2Manufacturing precision
If conventional resist application methods (spin-coating, screen-printing, photolithography) are used, then resist pattern formation is achieved, but application time and manufacturing cost increase
Solution Approach 1:
The patent replaces conventional mechanical resist application methods (spin-coating, screen-printing, photolithography) with a dispenser-based resist application system. The dispenser directly deposits resist material in controlled droplets onto specific conductor patterns, eliminating the need for complex photolithography processes and reducing application time while maintaining pattern precision through controlled dispensing positions and volumes.
3Manufacturing precision
If resist pattern is applied to prevent solder flow-out, then soldering precision is improved, but camera unit misalignment and field of view degradation occur
Solution Approach 1:
The resist pattern is strategically applied only to the second conductor pattern connecting to the central electrode, creating a localized solder containment zone. This prevents excessive solder flow that could cause misalignment while maintaining open pathways for the first conductor patterns, allowing controlled solder flow that supports proper camera unit positioning and field of view.
Solution Approach 2:
The patent converts the potential harm of unrestricted solder flow (which causes misalignment) into a benefit by using the absence of resist pattern on first conductor patterns to intentionally allow controlled solder flow. This controlled flow provides necessary solder for strong bonding while preventing the harmful effect of resist-induced misalignment.
Data Source
AI summary
A circuit device configured for use in an image pickup apparatus includes a plurality of first pads arranged in a two-dimensional pattern; a plurality of first conductors arranged in a two-dimensional pattern, each first conductor having a first end and a second end, the first ends being connected to the plurality of first pads, respectively; a plurality of lands connected to the second ends of the plurality of first conductors, respectively; a second pad disposed at a central region within the two-dimensional pattern of the plurality of first pads; a second conductor having a third end and a fourth end, the third end being connected to the second pad, the fourth end being connected to a specific pad among the plurality of first pads; and a resist portion covering at least a part of the second conductor but not any of the plurality of first conductors.