Folded Tele Camera OIS Layout for Slim Mobile Modules
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Solution Overview
Problem
Existing folded tele cameras face challenges in performing optical image stabilization (OIS) and focusing with complex actuation mechanisms, which often result in increased module height and width, making them unsuitable for slim mobile devices.
Innovation Solution
A folded-camera module with a lens configuration that includes a first and second lens group and an optical path folding element, allowing for spatial adjustment of these elements to compensate for optical path shifts during movement, thereby enabling OIS without significantly increasing the module's height and width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex actuation mechanisms are used for OIS and focusing, then stabilization and focusing performance is improved, but module height and width increase
Solution Approach 1:
The lens system is divided into multiple lens groups (first lens group with positive power, second lens group with negative power, third lens group with positive power) that can move independently. This segmentation allows each group to contribute differently to focusing and OIS functions, achieving complex functionality with simpler individual actuation mechanisms for each group rather than requiring a single complex mechanism.
Solution Approach 2:
The patent introduces an optical path folding element (prism or mirror) that folds the optical path at approximately 45 degrees, changing the dimensional arrangement of optical components. This allows the optical axis to be oriented perpendicular to the sensor surface, enabling OIS and focusing functionality within a compact module footprint by utilizing spatial folding rather than linear extension.
2Reliability
If lens groups are moved for OIS compensation, then image stabilization is achieved, but actuation complexity increases
Solution Approach 1:
The patent combines multiple functions into the movement of lens groups: the first and second lens groups work together as a unit for OIS compensation, while the second and third lens groups collaborate for focusing. This merging of functions into coordinated group movements reduces the number of independent actuation mechanisms needed, simplifying the overall actuation system while maintaining stabilization performance.
3Length of stationary object
If multiple lens groups are used for compact design, then module size is reduced, but manufacturing complexity increases
Solution Approach 1:
Each lens group is assigned a specific optical power (first group: positive, second group: negative, third group: positive) and specific movement characteristics (first and second groups move together for OIS, second and third groups move together for focusing). This local differentiation of optical properties and movement behaviors allows the complex multi-group system to be manufactured using standardized processes for each group type, reducing overall manufacturing complexity despite the multiple groups.
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 solution allows for effective OIS and focusing with simple actuation, maintaining a compact form factor suitable for slim mobile devices by minimizing the module's height and width, and achieving an f-number less than 3.5.
Implementation Method 1
an optical path folding element (OPFE), configured to fold a first optical axis onto a second optical axis
Data Source
AI summary
A folded-camera module for a mobile device. The folded-camera module includes a lens having an effective focal length in the range of 8 mm to 50 mm and having a f/# lesser than 3.5. The lens is comprising a first lens group (G1) and a second lens group (G2). The folded-camera module includes an optical path folding element (OPFE). The first lens group is positioned at an object side of the OPFE, and the second lens group is positioned at an image side of the OPFE. The folded-camera module is further configured for spatially adjusting at least one of the first lens group, the second lens group, and the OPFE, so as to compensate for an optical path shift of light entering into the folded camera module due to movements of the camera module, thereby providing optical image stabilization.