Camera Module Coil Layout for Hall Sensor Sensitivity
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Solution Overview
Problem
The measurement sensitivity of Hall sensors in camera devices is compromised due to electromagnetic interactions in voice coil motors, affecting autofocus and image stabilization functions.
Innovation Solution
A camera device configuration that includes a first driving unit and a second driving unit with a Hall sensor and a second coil positioned to enhance magnetic field detection, where the second coil is disposed to overlap with the central region of the first coil and the Hall sensor, with opposite magnetic field directions and current flow, and a fine pattern coil for improved sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voice coil motor is used for autofocus and image stabilization, then the camera device achieves automatic focus adjustment and hand shake correction, but the measurement sensitivity of the Hall sensor is lowered due to electromagnetic interaction between the coils and magnets
Solution Approach 1:
A magnetic shielding layer is introduced between the voice coil motor components (first coil and magnet) and the Hall sensor. This intermediary layer blocks the electromagnetic interaction that causes noise in the Hall sensor measurements, while allowing the voice coil motor to continue functioning for autofocus and image stabilization. The shielding layer acts as a mediator that separates the two systems to prevent interference.
Solution Approach 2:
The harmful electromagnetic interaction is extracted and isolated from the Hall sensor measurement path. By placing the magnetic shielding layer, the noise-generating electromagnetic field is effectively removed from the sensor's detection environment, allowing the Hall sensor to measure position accurately without interference from the voice coil motor operations.
2Measurement precision
If additional circuitry is added to improve Hall sensor sensitivity, then measurement accuracy improves, but device complexity and manufacturing cost increase
Solution Approach 1:
Instead of adding complex circuitry to compensate for the electromagnetic interference, the invention uses a passive magnetic shielding layer that naturally blocks the harmful electromagnetic fields. This approach converts the problem of electromagnetic interference into a simple structural solution, avoiding the need for additional active circuitry or signal processing complexity.
Solution Approach 2:
The magnetic shielding layer is implemented as a simple, thin structural component rather than complex electronics. This disposable-like structural element is inexpensive to manufacture and integrate, providing effective noise shielding without the high cost and complexity of additional circuitry or sophisticated signal processing systems.
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 enhances the measurement sensitivity of the Hall sensor, reducing noise and improving the accuracy of autofocus and image stabilization functions without additional circuitry, while also reducing manufacturing costs.
Implementation Method 1
the movement of the magnet is sensed through the Hall sensor
Implementation Method 2
Voice coil motors use electromagnetic interaction between magnets and coils
Implementation Method 3
the direction of the magnetic field generated by the second coil is opposite to the direction of the magnetic field generated by the first coil
Data Source
AI summary
A camera device according to the present embodiment comprises: a first operation part comprising one of a first coil or a magnet and arranged on a fixed member; a second operation part which comprises the other one of the first coil and the magnet, is arranged on a movable member, and faces the first operation part; a hall sensor facing one of the first operation part and the second operation part; and a second coil arranged near the hall sensor, wherein at least a portion of the second coil is arranged between the hall sensor and the first coil.