Multi-aperture optics alignment using reference object detection
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Solution Overview
Problem
Conventional active alignment methods for multi-aperture optics in miniaturized camera modules face challenges due to small changes in image sharpness with lenses having a large depth of field, and existing devices are not suitable for non-rotationally symmetrical lenses, leading to insufficient accuracy in aligning multi-aperture optics with image sensors.
Innovation Solution
A device and method for relative positioning of multi-aperture optics using a reference object detected by the image sensor, allowing precise alignment based on comparisons of actual positions with global or local centers, enabling adjustment through a positioning device controlled by a calculation device to achieve high image quality and low manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional active alignment methods are used with multi-aperture optics having large depth of field, then the alignment process can be performed, but the measurement precision of image sharpness changes becomes insufficient
Solution Approach 1:
The patent introduces a reference object with known geometric features as an intermediary element. Instead of directly measuring image sharpness changes of the multi-aperture optics, the system images the reference object and measures positional deviations of its features. This intermediary reference object transforms the measurement task from evaluating subtle sharpness changes to detecting precise positional shifts, thereby resolving the measurement precision problem.
Solution Approach 2:
The patent changes the measurement parameter from image sharpness (contrast/MTF) to positional deviation of reference features. By evaluating the positions of imaged reference object features relative to their expected locations, the system achieves more sensitive and reliable measurements for multi-aperture optics with large depth of field, where sharpness changes are too subtle to measure accurately.
2Adaptability or versatility
If conventional five-degree-of-freedom positioning is used for rotationally symmetrical lenses, then the alignment process is simple, but it is not suitable for non-rotationally symmetrical multi-aperture optics
Solution Approach 1:
The patent employs a universal positioning system that can handle both rotationally symmetrical and non-rotationally symmetrical optics. By using a reference object with known features and evaluating positional deviations in multiple directions, the same system architecture achieves six-degree-of-freedom alignment capability, making it adaptable to various lens types without requiring separate specialized systems.
Solution Approach 2:
The patent extends the alignment capability from five to six degrees of freedom by adding rotational alignment around the optical axis. The reference object methodology enables detection and correction of rotational misalignment by analyzing angular deviations of imaged features, thereby adding the sixth degree of freedom to the positioning system without fundamentally changing the system architecture.
3Manufacturing precision
If the center position of aperture is not precisely aligned with the center of partial image, then manufacturing is easier, but the reconstruction accuracy and resolution of overall image deteriorates
Solution Approach 1:
The patent implements a feedback-based active alignment process. The reference object is imaged through the multi-aperture optics, and the positions of imaged features are measured and compared to their expected positions. The positional deviations provide feedback that drives adjustments to the relative positioning between optics and sensor, enabling precise alignment to be achieved and verified through iterative measurement and correction.
Data Source
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AI summary
The invention relates to a device for positioning a multi-aperture optical unit with multiple optical channels relative to an image sensor, comprising a reference object, a positioning device, and a calculating device. The reference object is arranged such that the reference object is imaged in the optical channels onto an image region per channel by the multi-aperture optical unit. The positioning device can be controlled in order to change a relative position between the multi-aperture optical unit and the image sensor. The calculating device is designed to determine actual positions of the reference object in images of the reference object in at least three image regions and to control the positioning device on the basis of a comparison of the actual positions with positions.