Sensor-Shifting Autofocus Camera with VCM Actuator
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Solution Overview
Problem
Small form factor cameras face challenges in achieving high-resolution autofocus while maintaining a compact design, as existing autofocus mechanisms often rely on moving the optical lens as a single rigid body, which limits flexibility and accuracy in compensating for unwanted motion.
Innovation Solution
A camera design incorporating a voice coil motor (VCM) actuator that moves the image sensor relative to the lens group, utilizing a suspension arrangement and flexure structure to enable precise autofocus motion parallel to the optical axis, allowing for sensor-shifting autofocus functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical lens is moved as a single rigid body along the optical axis for autofocus, then the autofocus mechanism is simple to implement, but the autofocus accuracy and flexibility are limited
Solution Approach 1:
The patent divides the lens assembly into multiple independent movable lens groups rather than moving the entire lens as a single rigid body. Each lens group can be actuated independently by separate actuators, enabling more precise focal point control and flexible autofocus operation while maintaining a manageable mechanical structure
Solution Approach 2:
The patent introduces flexible suspension arrangements with elastic elements that allow the lens groups to move dynamically along the optical axis. This dynamic structure enables precise positioning through controlled movement of individual lens groups, improving autofocus accuracy while the modular design keeps the overall mechanism complexity manageable
2Volume of moving object
If the camera is designed with a compact form factor, then the device size is reduced for mobile applications, but the autofocus range and image stabilization capability are compromised
Solution Approach 1:
The patent enables lens groups to move not only along the optical axis (Z-direction) for autofocus but also in perpendicular directions (X and Y directions) through the flexible suspension arrangement. This multi-dimensional movement capability allows the compact camera to achieve both autofocus and optical image stabilization functions without requiring separate mechanisms, thereby maintaining a compact form factor while expanding functional adaptability
Solution Approach 2:
The flexible suspension arrangement serves multiple functions simultaneously: it supports autofocus by enabling axial movement of lens groups, provides optical image stabilization through perpendicular movement compensation, and maintains mechanical coupling between lens groups. This multi-functionality allows the compact camera design to achieve extended adaptability without proportionally increasing device volume
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 solution enables high-resolution imaging with improved autofocus accuracy and stability by allowing the image sensor to move independently, effectively compensating for external disturbances and maintaining a compact form factor.
Implementation Method 1
The VCM actuator may include one or more coils attached to a coil carrier, and one or more magnets attached to a stationary structure of the camera. The coil carrier may be attached to an image sensor package such that the image sensor is movable together with the coil carrier, in at least one direction parallel to an optical axis defined by the lens group.
Data Source
AI summary
Various embodiments include a camera having a sensor-shifting mechanism. For example, the camera may include a voice coil motor (VCM) actuator to move an image sensor, relative to a lens group, to provide autofocus (AF) functionality. According to some embodiments, the VCM actuator may include one or more coils attached to a coil carrier, and one or more magnets attached to a stationary structure of the camera. The coil carrier may be attached to an image sensor package such that the image sensor is movable together with the coil carrier, in at least one direction parallel to an optical axis defined by the lens group. In some embodiments, the camera may include one or more suspension arrangements to suspend the coil carrier and/or the image sensor package from one or more stationary structures of the camera.