Liquid Lens Optical Assembly for Compact Wide-Angle Autofocus
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Solution Overview
Problem
Existing imaging systems for machine vision face challenges in achieving a wide field of view, high resolution, and autofocusing capabilities while maintaining a small form factor, often relying on complex and costly electromechanical components that increase size and risk mechanical failures.
Innovation Solution
An optical assembly comprising three lens groups and a liquid lens that corrects for spherical aberrations, optical field curvature, and distortion, using a combination of plastic and glass aspheric lenses, along with a liquid lens for variable focusing, to achieve wide-angle autofocusing with a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If motors are used to move lenses for autofocusing, then autofocusing capability is achieved, but system size increases and mechanical reliability decreases
Solution Approach 1:
The patent replaces motor-driven mechanical lens movement with a liquid lens that achieves focusing through electrical control of liquid crystal or liquid droplet configuration. This eliminates motors, gears, and other mechanical moving parts while maintaining autofocusing capability through electronic actuation of the liquid lens optical properties
Solution Approach 2:
The patent employs a liquid lens utilizing liquid crystal or liquid droplet mechanisms controlled by electrical signals. The liquid medium enables continuous focal length adjustment through voltage control, replacing mechanical displacement with fluid-based optical property modification for compact, reliable autofocusing
2Measurement precision
If multiple lens elements are used in high resolution imaging cameras, then imaging quality improves, but lens cost increases
Solution Approach 1:
The patent combines plastic aspheric lenses with a liquid lens element to achieve high imaging quality. The plastic lenses provide structural support and initial optical correction, while the liquid lens adds variable focusing capability and additional aberration correction, creating a cost-effective composite optical system that rivals more expensive all-glass multi-element designs
Solution Approach 2:
The patent utilizes aspheric surfaces on plastic lens elements to correct optical aberrations more effectively than traditional spherical lenses. The aspheric profiles enable fewer total elements while maintaining high image quality, reducing manufacturing complexity and cost compared to multiple spherical glass elements
3Area of stationary object
If a wide field of view is achieved, then scanning coverage improves, but image sharpness and focus control become more difficult
Solution Approach 1:
The patent employs a dynamically adjustable liquid lens that can continuously change its focal length in response to object distance variations. This dynamic focusing capability maintains image sharpness across the wide field of view by adapting the optical power in real-time, overcoming the static focus limitations of traditional wide-angle lenses
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 solution provides a compact, cost-effective imaging system capable of capturing high-resolution images over a wide range of focal distances, reducing mechanical complexity and size, and enhancing image quality with improved aberration correction.
Implementation Method 1
a liquid lens disposed along the optical axis configured to receive the light from the first lens group and further configured to variably focus an image at distances from three inches to infinity
Implementation Method 2
a first lens group disposed along an optical axis configured to receive light from the object of interest and configured to correct for spherical aberrations of an image projected by a third lens group
Implementation Method 3
a second lens group disposed along the optical axis configured to receive the light from the liquid lens and further configured to correct for optical aberrations, and to magnify an image projected by the third lens group
Implementation Method 4
the third lens group disposed along the optical axis configured to receive the light from the second lens group and further configured to correct for optical field curvature and distortion of the image projected by the third lens group
Data Source
AI summary
A method and apparatus for capturing an image of at least one object appearing in a field of view (FOV). A housing has an image sensor an autofocusing lens assembly fixedly mounted relative thereto. The autofocusing lens assembly employs multiple lens groups and a liquid lens. The lens groups, liquid lens, and the image sensor are aligned such that light received within the FOV passes through the lens groups and liquid lens and impinges onto the image sensor. The image sensor generates an electrical signal indicative of the received image.