Phase Mask Lens System Uniformizes MTF for Extended Depth of Field
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Solution Overview
Problem
Fixed focus optical systems face challenges in capturing clear images of both near and far objects due to degradation of point spread functions, leading to unfocused images, and existing auto-focusing systems increase the volume and weight of optical devices.
Innovation Solution
An image capturing lens system with a phase mask that uniformizes the modulation transfer function (MTF) of light, regardless of incident length, angle, and wavelength, using a design with multiple lenses and a phase mask that satisfies specific phase mask functions, allowing for symmetrical lens arrangement and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed focus optical system is used, then the device complexity is reduced, but the image quality degrades for objects at different distances
Solution Approach 1:
A phase mask is introduced as an intermediary element between the lens and image sensor. This phase mask modulates the light waves to compensate for defocus effects, enabling high-quality imaging at multiple distances without requiring mechanical focusing mechanisms, thus maintaining simple device structure while improving image quality across different object distances
Solution Approach 2:
The system changes the optical parameters by introducing a phase mask with specific transmission functions that modify the wavefront phase. This parameter change enables the system to achieve extended depth of field and maintain image quality across a range of object distances, resolving the contradiction between simple fixed-focus structure and consistent image quality
2Manufacturing precision
If an auto-focusing optical system is used, then the image quality is improved for objects at different distances, but the device volume and weight increase
Solution Approach 1:
The patent replaces the mechanical auto-focusing system with an optical/phase-based solution. Instead of moving lens elements or sensors mechanically to achieve focus, a phase mask is used to optically compensate for defocus, eliminating the need for motors, actuators, and control mechanisms, thus reducing device volume and weight while maintaining image quality
Solution Approach 2:
The phase mask serves as a static intermediary that provides focusing functionality without mechanical movement. This single optical element replaces complex mechanical focusing subsystems, achieving the same image quality improvement with significantly reduced device volume and weight
3Manufacturing precision
If an auto-focusing optical system is used, then the image quality is improved for objects at different distances, but the device weight increases
Solution Approach 1:
The patent replaces heavy mechanical auto-focusing components (motors, actuators, movable lens groups) with a lightweight phase mask. This substitution eliminates the need for power-consuming moving parts while maintaining the ability to capture sharp images at various distances, significantly reducing device weight
Solution Approach 2:
The patent extracts the focusing functionality from the mechanical domain and implements it purely in the optical domain through phase modulation. This extraction removes the heavy mechanical subsystems while retaining the essential image quality improvement, achieving weight reduction without sacrificing performance
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-quality image capture across a wide focal length range, simplifies post-processing by restoring images to their original state, and reduces complexity through one-dimensional signal processing, while minimizing wave aberration and maintaining high aperture and field of view.
Implementation Method 1
a phase mask which is located in the image capturing lens group and satisfies phase mask functions that are defined with respect to x and y axes such that a modulation transfer function (MTF) of light is uniformized
Data Source
AI summary
Disclosed is an image capturing lens system. The image capturing lens system includes an image capturing lens group having a plurality of lenses and a phase mask located in the image capturing lens group. The phase mask may satisfy phase mask functions that are defined with respect to x and y axes such that a modulation transfer function (MTF) of light is uniformized.