Actuator Driver Lens Position Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional camera modules rely on Hall elements and permanent magnets for lens position detection, increasing costs and difficulty in reducing module size, and are prone to temperature fluctuations and individual variations.
Innovation Solution
The use of a position detection coil that generates an induced electromotive force in response to a magnetic field, eliminating the need for Hall elements and permanent magnets, and integrating the coil within the image sensor to ensure precise alignment and reduce noise effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall element and permanent magnet are used for lens position detection, then position detection function is achieved, but cost increases and module size increases
Solution Approach 1:
The patent extracts and eliminates the permanent magnet component from the system by using a voice coil actuator that generates its own magnetic field. The position detection is achieved through electromagnetic induction between the voice coil and a detection coil, removing the need for separate permanent magnets and Hall elements, thereby reducing module size and cost while maintaining detection functionality
Solution Approach 2:
The voice coil actuator serves dual functions: it acts as both the driving motor for lens movement and as a magnetic field generating unit for position detection. By making the actuator universal, the patent eliminates the need for separate detection components (Hall elements and permanent magnets), reducing overall device complexity and size
2Measurement precision
If a Hall element is used for lens position detection, then position detection function is achieved, but cost increases
Solution Approach 1:
The patent replaces expensive Hall elements with a simpler electromagnetic induction-based detection system using standard coils. The detection mechanism uses readily available components (voice coil and detection coil) rather than specialized semiconductor devices, significantly reducing manufacturing cost while achieving the same position detection function
Solution Approach 2:
The patent replaces the semiconductor-based Hall effect detection system with an electromagnetic induction-based system using simple coils. This substitution uses classical electromagnetic principles instead of quantum mechanical effects, enabling the use of cheaper, more manufacturable components while maintaining detection capability
3Measurement precision
If a Hall element is used for lens position detection, then position detection function is achieved, but temperature fluctuation and individual variation cause problems
Solution Approach 1:
The patent changes the detection principle from Hall effect (which is sensitive to temperature and individual variations) to electromagnetic induction. By using the induction principle, the detection system becomes inherently more stable against temperature fluctuations and individual component variations, as the magnetic field generation and detection are based on universal electromagnetic laws rather than material-specific quantum effects
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 allows for cost-effective, compact camera modules with high-precision lens position detection, resistant to temperature fluctuations and individual variations, and minimizes radiation noise-induced image quality degradation.
Implementation Method 1
a position detection coil arranged in an area that surrounds the image acquisition area... the induced electromotive force that occurs in the position detection coil changes according to the position of the lens
Data Source
AI summary
An image sensor includes a pixel array including multiple pixels. A lens is provided on an optical path of incident light to the image sensor. An actuator includes a coil, and supports positioning of the lens according to a driving signal applied to the coil. A position detection coil is arranged such that it magnetically couples with the coil of the actuator. An actuator driver supplies a pulse-shaped driving signal to the coil of the actuator driver. A position detection circuit generates a position detection signal that indicates the position of the lens based on an induced electromotive force that occurs in the position detection coil according to the driving signal, and feeds back the position detection signal to the actuator driver.