Adaptive Aperture Mechanism for Folded Telephoto Camera Depth of Field Control
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Solution Overview
Problem
Folded Tele cameras face challenges in controlling the amount of light reaching the sensor and maintaining a suitable depth of field (DOF), particularly due to their long focal length and large aperture, which results in a very shallow DOF, making it difficult to keep objects at different distances in focus.
Innovation Solution
The implementation of an adaptive aperture system in folded Tele cameras, which allows for the adjustment of the aperture size based on scene conditions, enables control over the amount of light and DOF without increasing the camera module height. This system uses a linearly sliding diaphragm with a pair or plurality of overlapping blades, actuated by an appropriate mechanism, to form an adaptive aperture of desired size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a long focal length and large aperture are used in folded Tele cameras, then the optical resolution and low-light imaging capability are improved, but the depth of field becomes very shallow, making it difficult to keep objects at different distances in focus
Solution Approach 1:
The patent applies a variable aperture mechanism that allows the aperture size to be dynamically adjusted during operation. The aperture can be changed from a fixed large opening to a variable size, enabling the system to adapt between low-light imaging mode (large aperture) and deep-focus mode (small aperture), thus resolving the contradiction between light intake and depth of field control
Solution Approach 2:
The patent changes the aperture parameter from a fixed value to a variable parameter that can be adjusted based on imaging requirements. By varying the aperture size (f-number) dynamically, the system can optimize both light intake for low-light conditions and depth of field for scenes requiring focus across different distances
2Manufacturing precision
If a fixed large aperture is used in folded Tele cameras, then the optical resolution is improved, but the adaptability to different scene conditions and depth requirements is reduced
Solution Approach 1:
The patent implements a dynamic aperture adjustment mechanism that allows the aperture size to be changed based on scene conditions. The system can switch between a fixed large aperture for optimal optical resolution in controlled conditions and a variable aperture for adapting to different lighting and depth requirements, thus maintaining high optical resolution while improving adaptability
3Adaptability or versatility
If an adaptive aperture mechanism is added to control depth of field, then the depth of field control capability is improved, but the camera module height increases
Solution Approach 1:
The patent integrates the adaptive aperture mechanism within the existing camera module structure, nesting the aperture adjustment components within the lens barrel or housing. This nested configuration allows the aperture control functionality to be incorporated without significantly increasing the overall module height, as the components share the existing spatial envelope
Data Source
AI summary
Systems comprising a folded camera that includes a lens module with a native aperture, the lens module having a height HM, an adaptive aperture located between the native aperture and an optical path folding element, and an adaptive aperture forming mechanism for forming the adaptive aperture, wherein the adaptive aperture forming mechanism has a height HAA not larger than HM, and methods of using same. In various embodiments, the adaptive aperture forming mechanism includes an actuator and at least one pair of blades operative to be moved by the actuator to a plurality of positions to form the adaptive aperture.