Folded Zoom Lens Layout for Bright Low-Profile Phone Cameras
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Solution Overview
Problem
Conventional small cameras in mobile devices struggle to capture high-resolution, high-quality images with variable magnification due to physical constraints, requiring improved optical systems that maintain compactness while achieving high brightness and resolution.
Innovation Solution
A folded lens system with movable lens groups and a light-folding element, such as a prism or mirror, allows for variable magnification and focal length adjustment using actuators controlled by a controller, enabling a zoom feature with continuous or discrete focal length changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional lens system is used in small form factor cameras, then the device can be compact, but the image resolution and quality deteriorate
Solution Approach 1:
The patent introduces a light-folding element (prism or mirror) that folds the optical path, effectively adding a spatial dimension to the lens system design. This allows the optical path length to be extended without increasing the linear dimensions of the camera module, thereby achieving high-resolution imaging capability while maintaining a compact form factor suitable for mobile devices.
Solution Approach 2:
The patent employs a nested arrangement where the light-folding element is integrated within the lens assembly structure. The prism or mirror is positioned within the optical path in a space-efficient manner, allowing multiple optical components to be nested together, maximizing the use of available space while achieving the required optical performance.
2Manufacturing precision
If the focal length is increased to achieve variable magnification, then the image quality improves, but the device complexity increases
Solution Approach 1:
The patent implements a movable lens group that can be positioned at different locations along the optical axis to achieve variable magnification. The lens group is movable between a first position (providing first magnification) and a second position (providing second magnification), enabling dynamic adjustment of the focal length and image magnification without requiring multiple fixed lens assemblies, thus managing device complexity while improving image quality.
Solution Approach 2:
The single movable lens group serves multiple functions: it enables variable magnification (zoom capability), maintains focus across different magnification levels, and achieves both wide-angle and telephoto imaging modes. This multi-functional design eliminates the need for separate lens assemblies for different magnification levels, reducing overall device complexity while achieving high image quality across the zoom range.
3Illumination intensity
If the f-number is reduced to increase brightness, then the image brightness improves, but the lens system size increases
Solution Approach 1:
The light-folding element (prism or mirror) redirects light at approximately 90 degrees, allowing the optical path to be folded back on itself. This enables a larger effective aperture diameter (lower f-number) without proportionally increasing the linear dimensions of the lens system, as the light path length is extended in a folded configuration rather than a straight line, thus achieving high brightness while controlling overall size.
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 system achieves high-resolution, high-brightness images with variable magnification, maintaining a compact form factor suitable for small form factor cameras, and supports focal lengths between 78 mm and 130 mm in 35 mm equivalent focal length with an f-number less than f/3.0.
Implementation Method 1
A folded lens system with movable lens groups and a light-folding element, such as a prism or mirror
Implementation Method 2
A folded lens system with movable lens groups and a light-folding element
Data Source
AI summary
A lens system provides a zoom function (variable magnification) in a low profile camera (lens system height less than or equal to 6 mm), which may be in a cellular phone. The lens system includes at least three movable lens groups that are movable along a common optical axis. Each of the three movable lens groups is coupled to a corresponding actuator. Responsive to a request to change focal length or magnification, a controller sends a corresponding signal to each of the actuators that move the corresponding lens group by a corresponding distance in a corresponding direction. The various movable lens groups may be moved by different distances and in different directions of movement. An f-number of the lens system is less than f/3.0. Focusing of an image cast onto an image sensor is accomplished by adjusting the position along the optical axis of one of the movable lens groups.