Sensor Shift Autofocus Actuator Arrangement
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Solution Overview
Problem
Small form factor cameras face challenges in achieving high-resolution imaging with optical image stabilization and autofocus, as existing systems often compromise on image sensor size, optical distortion, and mechanical complexity, leading to image quality degradation and reliability issues.
Innovation Solution
The camera system employs a tilt actuator arrangement using voice coil motor (VCM) actuators with fixed drive magnets and coils, allowing the image sensor to tilt about multiple axes for optical image stabilization and autofocus, while electromagnetic and air damping mechanisms provide motion control, reducing mechanical complexity and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical lens is moved as a single rigid body along the optical axis for autofocus, then the autofocus function is achieved, but the mechanical complexity and potential for misalignment increase
Solution Approach 1:
The camera system segments the autofocus mechanism by separating the lens group from the image sensor. Instead of moving the entire lens assembly, only the image sensor is moved along the optical axis by a linear actuator. This segmentation reduces mechanical complexity by eliminating the need for complex lens mounting and driving mechanisms while maintaining reliable autofocus functionality through independent sensor positioning.
Solution Approach 2:
The patent inverts the traditional autofocus approach by keeping the lens group stationary and moving the image sensor instead. Conventionally, the lens is moved to adjust focus; this patent reverses that paradigm by moving the sensor plane along the optical axis relative to the fixed lens group, thereby simplifying the mechanical structure while achieving the same optical focusing effect.
2Manufacturing precision
If larger image sensors are used to improve image quality, then the imaging resolution is improved, but the module footprint increases
Solution Approach 1:
The patent utilizes the optical axis dimension (Z-axis) to accommodate larger image sensors without increasing the lateral footprint (X-Y plane). By enabling movement of the image sensor along the optical axis for both autofocus and optical stabilization, the system can house larger sensors in a compact form factor, effectively trading depth for width to maintain small module dimensions while supporting high-resolution imaging.
3Reliability
If optical image stabilization is implemented by moving the lens, then the stabilization function is achieved, but the mechanical complexity increases
Solution Approach 1:
The patent merges the autofocus and optical image stabilization functions into a single actuator system. The linear actuator that moves the image sensor along the optical axis for autofocus also provides the stabilization function by compensating for angular vibrations. This consolidation eliminates the need for separate stabilization mechanisms, reducing mechanical complexity while maintaining both functions.
Solution Approach 2:
The image sensor positioning mechanism is designed with multi-functionality, serving both autofocus and optical image stabilization purposes. By making the sensor movement system universal, the patent eliminates redundant mechanical components and simplifies the overall structure, achieving reliable stabilization without increasing device complexity.
4Manufacturing precision
If complex alignment processes are used to achieve precise focusing, then the manufacturing precision is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The patent replaces complex mechanical alignment and adjustment mechanisms with a linear actuator system that provides controlled, repeatable movement of the image sensor along the optical axis. This substitution of precision mechanical assemblies with an actuated positioning system simplifies manufacturing by enabling programmable positioning and reducing the need for manual alignment procedures, thereby improving ease of manufacture while maintaining focusing precision.
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 improved optical image stabilization and autofocus performance with larger image sensors without increasing module footprint, reduces optical aberrations, and enhances reliability by simplifying the mechanical design and eliminating the need for complex alignment processes.
Implementation Method 1
one or more of the drive coils are capable of electromagnetically interacting with one or more of the fixed drive magnets to tilt the image sensor relative to the lens group
Implementation Method 2
electromagnetic and air damping mechanisms provide motion control
Implementation Method 3
electromagnetic and air damping mechanisms provide motion control
Data Source
AI summary
Various embodiments include a camera system having an autofocus (AF) actuator arrangement for moving an image sensor to provide AF. For example, the AF actuator may be used to move the image sensor, relative to a lens group of the camera system, in at least one direction parallel to an optical axis of the camera system. The AF actuator arrangement may include one or more voice coil motor (VCM) actuators. According to various embodiments, the VCM actuator(s) may include fixed drive magnets and movable drive coils. The drive magnets may be coupled with a housing of the camera system. The drive coils may be coupled with a substrate, and the substrate may also be coupled with the image sensor, such that the image sensor and the substrate move together.