Fixed Focus Camera Module Using Axial Chromatic Aberration for Near-Field Recognition
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Solution Overview
Problem
Conventional digital imaging devices face challenges in capturing high-resolution images with a large field of view while maintaining a compact form factor, as larger optical total track lengths limit their applications, and existing lens assemblies struggle to provide both far and near-field image focus effectively.
Innovation Solution
A lens assembly design that induces axial chromatic aberration to focus blue light at a shorter focal distance than green and red light, allowing for improved near-field image recognition and maintaining good far-field image quality, with a compact form factor and reduced optical total track length, using a combination of six discrete lenses and an infrared cut filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a larger optical total track length is used in the lens assembly, then the field of view and image resolution are improved, but the device size and space constraints are worsened
Solution Approach 1:
The patent introduces axial chromatic aberration as a deliberate parameter change, allowing blue light to focus at a different distance than green and red light. This enables the lens to capture near-field objects sharply using the blue channel while maintaining acceptable far-field quality through multi-channel image processing, thereby achieving high resolution without increasing optical TTL
Solution Approach 2:
The lens assembly is designed to serve multiple functions: capturing far-field images with acceptable quality for general photography, and capturing near-field images with enhanced quality for image recognition tasks. The multi-channel image processing system allows the same optical system to be optimized for different应用场景 (application scenarios)
2Measurement precision
If a conventional lens assembly is used, then the far-field image quality is maintained, but the near-field image recognition capability is insufficient
Solution Approach 1:
The patent deliberately introduces axial chromatic aberration parameter change, causing blue light to focus at a shorter distance than green and red light. This physical parameter change enables near-field objects to be captured with sharper focus in the blue channel, improving near-field image recognition while the multi-channel processing maintains far-field quality
Solution Approach 2:
The patent uses multi-channel image processing as an intermediary mechanism to reconcile the trade-off between near-field and far-field quality. By processing images from multiple color channels (RGB) and selectively utilizing the blue channel for near-field enhancement while maintaining other channels for far-field quality, the system achieves both objectives
3Volume of moving object
If the optical total track length is reduced for compact form factor, then the device portability is improved, but the field of view and image quality are worsened
Solution Approach 1:
The patent uses axial chromatic aberration introduction as a parameter change that allows compact lens design to achieve enhanced near-field image quality. The blue channel's shorter focal distance compensates for the reduced optical TTL, enabling high-quality near-field capture in a compact form factor
Solution Approach 2:
The patent segments the image processing into multiple color channels (RGB), with the blue channel specifically utilized for near-field image recognition enhancement. This segmentation allows different parts of the color spectrum to serve different functions, enabling compact design without sacrificing image quality
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 design achieves a 20% improvement in near-field image quality and maintains acceptable far-field image quality, enabling high-resolution images with a large field of view and compact form factor, suitable for head wearable displays and image recognition tasks.
Implementation Method 1
A lens assembly design that induces axial chromatic aberration to focus blue light at a shorter focal distance than green and red light
Implementation Method 2
using a combination of six discrete lenses and an infrared cut filter
Data Source
AI summary
A camera apparatus includes an image sensor to output an image signal, a stop aperture, a lens assembly, and a controller. The lens assembly is disposed between the image sensor on an image side of the lens assembly and the stop aperture on an object side of the lens assembly. The lens assembly includes a plurality of lens elements that collectively induce axial chromatic aberration between red, green, and blue light. The controller is coupled to receive red, green, and blue channels of the image signal. The controller includes logic that causes the controller to use the blue channel without the red or green channels of the image signal to perform image recognition on objects captured in a near-field of the lens assembly and to use the blue, red, and green channels collectively when capturing images in a far-field of the lens assembly.