Ball Bearing Sensor Shift for Camera OIS and AF in Tight Spaces
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Solution Overview
Problem
Small form factor cameras face challenges in achieving high-resolution image stabilization and autofocus due to limited space and the need to integrate with fixed magnets, which can interfere with other magnetic field sources.
Innovation Solution
A ball bearing sensor shift arrangement is introduced, which includes carrier frames configured to move on ball bearings, enabling the image sensor to move in multiple degrees-of-freedom. This arrangement couples with voice coil motor actuators containing fixed magnets, optical image stabilization coils, and autofocus coils, allowing for precise motion control of the image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed magnets are used in the camera, then the camera structure is simplified and manufacturing is easier, but magnetic interference with other field sources occurs
Solution Approach 1:
The patent extracts the magnets from the moving sensor assembly and fixes them to the camera housing. This separation allows the sensor to move freely on ball bearings for OIS and AF operations while the magnets remain stationary, eliminating magnetic interference with moving components and simplifying the overall structure.
Solution Approach 2:
The patent introduces ball bearings as an intermediary mechanism between the sensor assembly and the fixed magnets. This allows the sensor to move precisely in response to electromagnetic forces from the voice coil motors while the magnets themselves remain stationary, resolving the conflict between ease of manufacture and magnetic interference.
2Measurement precision
If the image sensor is moved for stabilization and focus, then image quality is improved, but the device complexity increases
Solution Approach 1:
The patent segments the sensor movement mechanism into independent degrees of freedom using separate carrier frames - one for optical image stabilization (OIS) and another for autofocus (AF). Each frame can move independently on ball bearings, allowing precise control of sensor position without requiring a complex monolithic movement mechanism.
Solution Approach 2:
The patent employs dynamic movement of the image sensor through ball bearing assemblies that allow smooth, low-friction motion in multiple directions. The sensor assembly can dynamically adjust its position in real-time in response to electromagnetic forces from voice coil motors, enabling precise stabilization and focus adjustment.
3Adaptability or versatility
If multiple degrees-of-freedom motion is enabled, then autofocus and optical image stabilization are achieved, but the device occupies more space
Solution Approach 1:
The patent merges the autofocus and optical image stabilization functions into a single integrated sensor assembly that moves on shared ball bearings. The carrier frames are designed to accommodate both OIS and AF operations simultaneously, reducing the overall space required compared to separate mechanisms.
Solution Approach 2:
The patent employs a nested structure where the OIS carrier frame and AF carrier frame are integrated within a compact sensor assembly. The ball bearing mechanisms are nested within the carrier frames, allowing multiple degrees of freedom motion while minimizing the overall volume occupied by the movement mechanism.
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 ball bearing sensor shift arrangement effectively enhances the camera's ability to stabilize images and focus by allowing for precise motion control of the image sensor in multiple axes, while minimizing interference from fixed magnets and allowing for flexible optic design scaling.
Implementation Method 1
A ball bearing sensor shift arrangement is introduced, which includes carrier frames configured to move on ball bearings, enabling the image sensor to move in multiple degrees-of-freedom
Implementation Method 2
This arrangement couples with voice coil motor actuators containing fixed magnets, optical image stabilization coils, and autofocus coils, allowing for precise motion control of the image sensor
Data Source
AI summary
A ball bearing sensor shift arrangement for a camera may include one or more voice coil motor (VCM) actuators that include the fixed magnets, optical image stabilization (OIS) coils, and/or one or more autofocus (AF) coils. The ball bearing sensor shift arrangement may be coupled with an image sensor of the camera, and may include carrier frames configured to move on ball bearings so as to enable motion of the image sensor in multiple degrees-of-freedom (DOF). An OIS carrier frame(s) may be coupled with the OIS coils, which may be positioned proximate the fixed magnets and used for moving the image sensor in directions orthogonal to an optical axis of the camera. An AF carrier frame may be coupled with the AF coil(s), which may be positioned proximate the fixed magnets and used for moving the image sensor in at least one direction parallel to the optical axis.