Image Sensor Actuator Layout for Precise AF and OIS Motion
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Solution Overview
Problem
Existing camera modules face challenges in implementing autofocus (AF) and optical image stabilization (OIS) functions due to the degradation of driving precision caused by wire deformation and the complexity of moving lens modules, which are heavy and affect movement accuracy and reliability.
Innovation Solution
A sensor-driving actuator that moves an image sensor instead of the lens module, utilizing a flexible circuit board with a bent structure to facilitate movement in multiple directions, incorporating magnets and guide rails with balls for precise positioning, and separate physical structures for AF and OIS functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lens module is moved to implement OIS and AF functions, then the optical image stabilization and autofocus can be achieved, but the heavy weight of the lens module degrades movement accuracy and reliability
Solution Approach 1:
Instead of moving the heavy lens module to achieve OIS and AF functions, the patent inverts the approach by moving the lighter image sensor while keeping the lens module stationary. This inversion significantly reduces the weight of the moving component, thereby improving movement accuracy and reliability without sacrificing the optical stabilization and autofocus capabilities.
2Manufacturing precision
If a wire-type device is used to support and restore the carrier position, then the carrier can be physically supported, but the wire deforms easily in physical properties which degrades driving precision
Solution Approach 1:
The patent removes the wire-type supporting device from the system entirely. Instead of using a wire to physically support and restore the carrier position, the invention employs a magnetic field-based actuator that generates electromagnetic force to move the image sensor directly, eliminating the wire and its associated deformation and precision degradation issues.
3Adaptability or versatility
If separate AF and OIS carriers are stacked to implement both functions, then both autofocus and optical image stabilization can be achieved, but the physical structure becomes complex
Solution Approach 1:
The patent combines the AF and OIS functions into a single integrated actuator system. The actuator includes a magnetic field generating unit that can produce magnetic fields in multiple directions, enabling both autofocus (axial movement) and optical image stabilization (lateral movement) functions to be achieved through a unified structure rather than separate stacked carriers, thereby reducing physical structure complexity.
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
The actuator improves the reliability and ease of implementing OIS and AF by minimizing tension on the flexible circuit board and reducing the weight of the moving components, enhancing the camera module's performance and alignment accuracy.
Implementation Method 1
generating an electromagnetic force between the coil and the magnet, thereby moving the movable body in the optical axis direction or a direction perpendicular to the optical axis
Implementation Method 2
a frictional force is minimized by a rotational motion of the ball and a point contact with the ball, such that the carrier moves more smoothly and accurately
Data Source
AI summary
A sensor-driving actuator is provided, which includes an image sensor; an OIS carrier to which the image sensor is mounted and which moves the image sensor in at least one of a first direction perpendicular to the optical axis direction or a second direction perpendicular to the first direction; an AF carrier for moving the image sensor in the optical axis direction; a first housing accommodating the OIS carrier and the AF carrier; a flexible circuit board which extends from an upper portion of the OIS carrier to which the image sensor is mounted, and which bends, along the outer surface of the first housing, in each of the optical axis direction and the direction perpendicular to the optical axis direction; and a second housing accommodating the first housing.