Folded Optics Multi-Camera System for Thin Device Imaging
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Solution Overview
Problem
Conventional mobile devices face challenges in maintaining image quality while reducing the thickness of imaging systems, as shortening the focal length leads to undesirable effects such as increased field of view, lens roll-off, and reduced resolution at the edges of images.
Innovation Solution
The implementation of folded optic sensor arrays with multiple image sensors and lens assemblies, where light is redirected using primary and secondary surfaces to maintain a longer focal length, allowing for optical zoom and more complex optics, and employing image stitching techniques to assemble partial images from overlapping fields of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the focal length of the imaging system is shortened to reduce device thickness, then the device profile is improved, but image quality deteriorates due to increased lens roll-off and reduced resolution at image edges
Solution Approach 1:
The patent introduces a folded optical path that redirects light at angles (e.g., 45-degree mirrors) to create a non-linear optical trajectory. This allows the optical axis to extend in multiple dimensions rather than a straight line, effectively increasing the functional focal length while maintaining a compact physical footprint in the primary device thickness dimension.
Solution Approach 2:
The patent embeds multiple optical components (mirrors, beam splitters, lenses) within a compact folded optical architecture where components are nested or arranged in space-efficient configurations. The folded path allows optical elements to be positioned in three-dimensional space rather than linear arrangement, nesting the optical train within a smaller envelope volume.
2Length of moving object
If the focal length is shortened to maintain thin device profile, then device thickness is reduced, but field of view becomes excessively wide and unnatural
Solution Approach 1:
The folded optical path redirects light rays through angular deviations using mirrors and beam splitters, allowing the optical system to achieve a longer effective focal length by traversing a multi-dimensional path rather than a straight line. This maintains natural field of view characteristics while keeping the physical device thickness minimal.
3Manufacturing precision
If multiple image sensors are used to capture different portions of the scene, then image quality and resolution are improved, but device complexity increases
Solution Approach 1:
The patent divides the imaging function across multiple image sensors, with each sensor capturing a specific portion of the optical path or field of view. Beam splitters and mirrors route different light paths to different sensors, enabling parallel capture of multiple image segments that are later combined to form a complete high-resolution image.
Solution Approach 2:
The folded optical system with multiple sensors serves multiple functions simultaneously: capturing wide-angle views, telephoto views, and intermediate focal lengths through different optical paths. The same optical train and sensor array configuration enables various imaging modes without requiring separate dedicated camera modules for each function.
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 approach enables the creation of low-profile imaging systems with improved resolution across the field of view, avoiding the degradation of image quality associated with shorter focal lengths and allowing for features like optical zoom and high dynamic range imaging.
Implementation Method 1
By redirecting light toward each sensor in the array using a primary and secondary surface
Data Source
AI summary
Described herein are methods and devices that employ a plurality of image sensors to capture a target image of a scene. As described, positioning at least one reflective or refractive surface near the plurality of image sensors enables the sensors to capture together an image of wider field of view and longer focal length than any sensor could capture individually by using the reflective or refractive surface to guide a portion of the image scene to each sensor. The different portions of the scene captured by the sensors may overlap, and may be aligned and cropped to generate the target image.