Hall Effect Sensor Flip-Chip Mounting for Encoder Resolution
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Solution Overview
Problem
Existing encoders with Hall Effect sensors face limitations in reducing the polar pitch and increasing resolution due to a minimal gap required between the sensor and magnetic disk, which affects accuracy and size reduction, and cannot position the magnetic sensor closer to the magnetic dipole without compromising mechanical strength.
Innovation Solution
The encoder design features a semiconductor die sensor with its sensitive area on the external face, flip chip mounted onto a circuit board with a reduced thickness attachment portion between the sensor and magnetic dipole, allowing closer proximity without compromising mechanical strength, enabling reduced packaging and increased resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between the magnetic disk and Hall Effect sensor is reduced to enhance accuracy and resolution, then measurement precision improves, but mechanical strength deteriorates due to the minimal gap required
Solution Approach 1:
The circuit board is designed with a localized thin region specifically at the sensor mounting area, while other areas maintain standard thickness for mechanical strength. This allows the sensor to be positioned extremely close to the magnetic disk (improving measurement precision) while the rest of the board retains sufficient structural integrity (maintaining mechanical strength).
Solution Approach 2:
Instead of reducing the overall thickness of the entire circuit board (which would compromise mechanical strength), the invention creates a localized thickness variation in the dimensional space where the sensor is mounted. This targeted approach allows proximity optimization without sacrificing overall structural rigidity.
2Volume of moving object
If the polar pitch is reduced to increase resolution and decrease encoder size, then encoder packaging is reduced, but magnetic field strength decreases making detection more difficult
Solution Approach 1:
The invention replaces conventional through-hole mounting with surface-mount technology (SMT) for mounting the Hall Effect sensor on the circuit board. This substitution allows the sensor to be positioned much closer to the magnetic disk, enabling the use of smaller polar pitches while maintaining sufficient magnetic field strength for accurate detection.
Solution Approach 2:
The invention changes the mounting parameters of the sensor system by using surface-mount technology with minimized standoff height. This parameter change allows the sensor to operate effectively with reduced polar pitch, as the magnetic field strength at the sensor location remains sufficient despite the smaller encoder dimensions.
3Length of stationary object
If the overall thickness of the circuit board is reduced to allow closer sensor positioning, then encoder packaging is reduced, but mechanical resistance deteriorates
Solution Approach 1:
The circuit board features a non-uniform thickness profile with a localized thin region at the sensor mounting area and standard thickness elsewhere. This local quality variation allows the sensor to be positioned as close as possible to the magnetic disk (reducing packaging) while the thicker portions of the board maintain sufficient mechanical resistance for structural integrity.
Solution Approach 2:
The circuit board is effectively segmented into functional zones: a thin region for sensor mounting where minimal thickness is required, and thicker regions for mechanical support. This segmentation allows each area to be optimized for its specific function without compromising the other.
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 design reduces the overall packaging size and increases resolution while maintaining mechanical strength, allowing for a stronger magnetic field detection without additional cost or technology shifts, such as switching to optical sensing.
Implementation Method 1
at least one magnetic sensor with a sensitive area arranged to detect a magnetic field created by the magnetic dipole
Data Source
AI summary
Encoder includinga moveable part with at least one magnetic dipole,at least one Hall Effect sensor with a sensitive area arranged to detect a magnetic field created by the magnetic dipole,at least one circuit board with a main thickness and having an attachment portion on which the Hall Effect sensor is mounted,where the Hall Effect sensor is a semiconductor die sensor with the sensitive area arranged on an external face of the semiconductor die,where the Hall Effect sensor is flip chip mounted onto the attachment portion of the circuit board, with the sensitive area in contact with the circuit board, and where the attachment portion is arranged between the Hall Effect sensor and the magnetic dipole and presents a reduced thickness compared to the main thickness of the rest of the circuit board.