Optical Scanning Device Connector Routing for Solder Reliability
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Solution Overview
Problem
Conventional optical scanning devices face issues with connector detachment due to concentrated tensile stress at the solder fillet of round-shaped terminal pins, leading to potential solder breakdown and connector detachment from the substrate.
Innovation Solution
The optical scanning device employs terminal pins with vertical portions extending vertically and bonding portions facing the same direction, with the connector cable routed in an opposite direction to reduce tensile stress and enhance solder bonding reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the connector cable is routed in the direction of the leading end of the solder bonding portion, then the cable can be connected easily, but tensile stress is concentrated on the solder fillet causing potential detachment
Solution Approach 1:
The patent inverts the conventional cable routing direction. Instead of routing the cable in the direction of the solder bonding portion leading end (which causes tensile stress concentration), the cable is routed in the opposite direction. This inversion transforms the stress distribution from concentrated at the solder fillet to distributed along the terminal pin body, thereby preventing connector detachment while maintaining connection ease
2Device complexity
If the terminal pin has a round shape, then the connector structure is simple, but the solder fillet bonded area is tapered causing stress concentration
Solution Approach 1:
The patent applies local quality by modifying the terminal pin geometry at specific locations. The terminal pin has a round shape overall for simplicity, but features a flattened portion at the solder bonding area. This local modification creates a uniform solder fillet bonded area without excessive complexity, distributing stress evenly and preventing concentration at the bonded interface
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 suppresses solder breakdown and connector detachment, ensuring a more reliable optical scanning device and image forming apparatus by distributing stress more evenly and reducing the risk of connector detachment.
Implementation Method 1
bonding portions bonded to a surface of the substrate by solder
Data Source
AI summary
An optical scanning device includes a polygon mirror, a motor driving the polygon mirror, a substrate on which the polygon mirror and the motor are mounted, and a connector mounted on the substrate using a surface mount technology. The connector is provided with a plurality of terminal pins including vertical portions extending substantially in a vertical direction with respect to a plane of the substrate and bonding portions bonded to a surface of the substrate by solder. In the plurality of terminal pins, each of leading ends of the bonding portions faces in a same first direction. In a state in which a cable which sends an electric power and an electric signal to the motor is connected to the connector, the cable is connected to the connector so as to extend in a second direction opposite to the first direction.