Camera Actuator Position Detection via Oscillation Circuit
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Solution Overview
Problem
Existing camera module actuators rely on hall sensors for precise magnet position detection, which increases manufacturing costs and reduces space efficiency.
Innovation Solution
An actuator system for camera modules that uses a magnet, coil, driver, and position estimator with an inductor to convert oscillation signals into digital signals, estimating the magnet's position without a hall sensor, utilizing delta sigma modulation and a magnetic body with high permeability to enhance inductance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hall sensor is used to detect magnet position, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the position detection function from a separate hall sensor and integrates it into the oscillation circuit itself. The oscillation circuit directly senses magnetic field changes through its inductor, eliminating the need for an external hall sensor while maintaining position detection capability.
Solution Approach 2:
The oscillation circuit serves dual purposes: it generates oscillation signals for driving the actuator and simultaneously detects magnet position through inductance changes. This multi-functionality reduces component count and simplifies the overall actuator structure.
2Measurement precision
If a hall sensor is used to detect magnet position, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the hall sensor component entirely, extracting its detection function into the oscillation circuit. This elimination of parts directly reduces manufacturing costs while maintaining detection precision through the inductance-based sensing mechanism.
Solution Approach 2:
The patent replaces the expensive hall sensor with a cost-effective oscillation circuit implementation using standard inductors and capacitors. This substitution uses inexpensive, readily available components to achieve the same functional outcome.
3Measurement precision
If a hall sensor is used to detect magnet position, then measurement precision is improved, but space efficiency decreases
Solution Approach 1:
The patent merges the position detection function with the existing oscillation circuit, combining what were previously separate functions into a single integrated system. This eliminates the need for additional space dedicated to hall sensor mounting and wiring.
Solution Approach 2:
The oscillation circuit performs both actuation and position detection functions within the same physical space, maximizing space utilization and eliminating the need for separate detection hardware that would occupy additional area.
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
Enables precise magnet position detection without hall sensors, reducing manufacturing costs and improving space efficiency while maintaining accurate auto-focusing capabilities.
Implementation Method 1
an oscillation circuit configured to generate an oscillation signal, wherein the oscillation circuit includes an inductor configured to determine a frequency of the oscillation signal... a frequency of the oscillation signal varies based on a position of the magnet
Implementation Method 2
A magnetic body having a high magnetic permeability and coated with a magnetic material may be formed between the magnet and the oscillator circuit, in order to raise a change ratio of an inductance of the inductor based on the position of the magnet
Implementation Method 3
a coil facing the magnet; a driver configured to apply a driving signal to the coil to move the magnet in a direction
Data Source
AI summary
An actuator of a camera module includes a magnet, a coil facing the magnet, a driver configured to apply a driving signal to the coil to move the magnet in a direction, and a position estimator. The position estimator is configured to convert an oscillation signal into a digital signal in a delta sigma modulation scheme, and estimate the position of the magnet from the digital signal. A frequency of the oscillation signal varies based on a position of the magnet.