Sensor Module Asymmetric Land Pattern Prevents Gyro Rotation
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Solution Overview
Problem
Existing sensor modules with orthogonal gyro sensors face detection accuracy issues due to package rotation during solder reflow, causing deviation of detection axes and reduced accuracy.
Innovation Solution
The sensor module design ensures that the width of the board land pattern is equal to or smaller than the package electrode width in one direction and larger in another, preventing rotational movement and enhancing joining strength, thereby maintaining accurate detection axis orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the board land pattern width is larger than the package electrode width, then the joining strength is improved, but the package rotates during solder reflow causing detection axis deviation
Solution Approach 1:
The patent changes the dimensional parameters of the board land pattern, specifically setting its width in the first direction to be equal to or smaller than the package electrode width (Xp≤X1), while maintaining sufficient joining strength through optimized dimensions in the second direction (Yp≥Y1). This parameter adjustment prevents rotational movement during solder reflow while ensuring adequate mechanical bonding.
Solution Approach 2:
The patent introduces asymmetric dimensional relationships between the board land pattern and package electrode. By making the width in the first direction Xp≤X1 while allowing the width in the second direction to be Yp≥Y1, the design creates an asymmetric configuration that prevents rotational movement during soldering while maintaining joining strength through the second direction's dimensional relationship.
2Measurement precision
If the board land pattern width is equal to or smaller than the package electrode width, then the detection axis orientation is maintained, but the joining strength may be reduced
Solution Approach 1:
The patent compensates for the reduced width in the first direction by optimizing the dimensional relationship in the second direction. By setting Yp≥Y1 (width of board land pattern in second direction ≥ width of package electrode in second direction), the design transfers the joining strength function to the second dimension, allowing Xp≤X1 to prevent rotation while Yp≥Y1 maintains adequate mechanical strength.
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 stabilizes the sensor package on the circuit board, preventing detection axis deviation and improving detection accuracy and joining reliability.
Implementation Method 1
joined to the board land pattern by a solder
Implementation Method 2
surface tension of a melted solder at the time of a solder reflow
Implementation Method 3
surface tension of a melted solder at the time of a solder reflow for mounting the package on the wiring board
Data Source
AI summary
A sensor module includes a circuit board, a sensor element having a detection axis along a planar direction of the circuit board, a sensor package accommodating the sensor element and mounted on the circuit board, a board land pattern used for mounting the sensor package disposed on the circuit board, and a package electrode disposed on a mounting surface of the sensor package facing the circuit board and joined to the board land pattern by a solder. A relationship of Xp≤X1 is satisfied, in which Xp is a width of the board land pattern in a first direction along the planar direction of the circuit board, and X1 is a width of the package electrode in the first direction.