Optical Lens Drive Magnet Layout for High Thrust in Compact Modules
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Solution Overview
Problem
Existing drive devices for optical systems face challenges in efficiently obtaining thrust while minimizing the device's size and weight, often resulting in increased dimensions in the radial direction.
Innovation Solution
The drive device incorporates a base portion with first and second magnets disposed at specific positions corresponding to different movement amounts, along with a first coil bonded to the optical system, and includes a position detection sensor and magnetism suppression member to enhance thrust efficiency and reduce dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single large magnet is used to cover the entire movement range, then sufficient thrust can be obtained, but the device dimensions in the radial direction increase
Solution Approach 1:
The patent divides the single large magnet into multiple smaller magnets (first magnet and second magnet) arranged at different positions along the optical axis. Each magnet corresponds to a specific movement amount range, allowing the system to generate sufficient thrust through multiple smaller magnetic fields rather than requiring one large radial magnet.
Solution Approach 2:
Instead of increasing the radial dimension to accommodate a larger magnet, the patent transitions to utilizing the optical axis direction (longitudinal dimension) by positioning multiple magnets at different depths. This dimensional shift allows thrust generation without increasing the device's radial footprint.
2Reliability
If magnets are positioned to cover the full movement range, then complete coverage is achieved, but self-demagnetization effects increase
Solution Approach 1:
By segmenting the magnetic coverage into distinct first and second magnets positioned at different locations, each magnet operates within its own optimized magnetic circuit path. This segmentation reduces the cumulative self-demagnetization effects that would occur in a single continuous magnet spanning the entire movement range.
Solution Approach 2:
Each magnet is positioned and dimensioned to provide optimal local magnetic field quality for its specific movement range. The first magnet is optimized for its corresponding movement amount while the second magnet is optimized for its range, allowing each to operate with reduced self-demagnetization rather than compromising the entire system for average performance.
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 efficient thrust generation with reduced dimensions, minimizing the drive device's size and weight by optimizing magnet placement and reducing self-demagnetization effects.
Implementation Method 1
the base portion drives the first coil and the optical system by an electromagnetic force generated in the first coil
Implementation Method 2
a magnet that is engaged with the coil
Implementation Method 3
a position detection sensor that includes a magnetic body and detects a position of the optical system by magnetism of the magnetic body
Data Source
AI summary
A drive device includes a magnetic circuit unit including a first yoke, a second yoke, and a first magnet, a magnetic circuit unit including the first yoke, the second yoke, a second magnet, a first coil that is bonded to a focus lens, in which the magnetic circuit units drive the first coil and the focus lens by an electromagnetic force generated in the first coil, the first magnet corresponds to a first movement amount of movement of the focus lens, and the second magnet corresponds to a second movement amount of movement of the focus lens.