Autofocus Lens Active Alignment for Consistent Rear Focusing Distance
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Solution Overview
Problem
Industrial scanners face challenges in optical alignment due to fabrication errors, leading to reduced image resolution and scanning performance, especially with larger optics being more susceptible to errors and smaller components being less robust.
Innovation Solution
A method for high-precision optical alignment involves positioning a lens holder at a calibrated back flange focal length from a calibration sensor, translating the front lens group to focus the image, and determining the calibrated position using a processor, allowing for active alignment and compensation for fabrication errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If larger optics are used to scan barcodes across wide ranges of distances, then scanning capability is improved, but fabrication errors increase leading to optical misalignment
Solution Approach 1:
The patent performs preliminary alignment actions by translating the lens holder and front lens group to calibrated positions before final assembly. The system determines calibrated positions of the lens holder relative to the image sensor and calibrated positions of the front lens group relative to the lens holder, establishing precise optical alignment beforehand to compensate for fabrication tolerances in larger optics
Solution Approach 2:
The patent employs feedback mechanisms where the system translates the lens holder to multiple positions, captures images at each position, and uses image analysis to determine the calibrated position that achieves optimal focus. This feedback loop allows the system to identify and correct alignment deviations caused by fabrication errors in larger optical components
2Volume of moving object
If smaller components are used to reduce size, then compactness is improved, but robustness to fabrication error decreases
Solution Approach 1:
The patent performs preliminary alignment actions by translating the lens holder and front lens group to calibrated positions before final assembly. The system determines calibrated positions of the lens holder relative to the image sensor and calibrated positions of the front lens group relative to the lens holder, establishing precise optical alignment beforehand to compensate for fabrication tolerances
Solution Approach 2:
The patent changes the positional parameters of optical components by translating the lens holder along the optical axis to calibrated positions. The system adjusts the distance between the lens holder and image sensor, and the position of the front lens group within the lens holder, to optimize optical alignment and compensate for fabrication variations in compact components
3Manufacturing precision
If high precision alignment is required to prevent optical distortion, then image quality is improved, but alignment complexity and time increase
Solution Approach 1:
The patent implements self-service alignment where the system automatically translates the lens holder to multiple positions, captures images, analyzes image quality, and determines the calibrated position without requiring manual intervention. The system autonomously identifies the optimal alignment position that minimizes optical distortion, eliminating the need for time-consuming manual alignment procedures
Solution Approach 2:
The patent employs feedback mechanisms where the system translates the lens holder to multiple positions, captures images at each position, and uses image analysis to determine the calibrated position that achieves optimal focus. This automated feedback loop rapidly identifies the correct alignment position, significantly reducing alignment time while maintaining high precision
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
This method achieves improved optical alignment with reduced misalignment errors, enabling the use of smaller, more compact lenses while maintaining high resolution and performance, even in larger optical systems capable of scanning at greater distances.
Implementation Method 1
Translating the front lens group changes a focal distance of the imaging system to focus the image onto the calibration sensor
Implementation Method 2
the actuator is one of a voice coil motor, a one-dimension translation stage, a piezoelectric device, a ball-bearing linear motor, or a microelectromechanical systems (MEMS) motor
Implementation Method 3
the actuator is one of a voice coil motor, a one-dimension translation stage, a piezoelectric device, a ball-bearing linear motor, or a microelectromechanical systems (MEMS) motor
Data Source
AI summary
An optical assembly for an autofocus imaging system for capturing at least one image of an object appearing in an imaging field of view (FOV) is provided. The optical assembly includes a front aperture along an optical axis and a front lens group along the optical axis that receives light from the object of interest. The position of the front lens group is adjustable to change a focal distance of the optical assembly. The optical assembly further includes an actuator physically coupled to the front lens group that adjusts the position of the front lens. A rear lens group is disposed along the optical axis to receive the light from the front lens group, and an imaging sensor is disposed at a back focal distance of the rear lens group, to detect the light.