Variable Focal Length Lens Device with Dual Imaging Paths
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Solution Overview
Problem
Conventional variable focal length lens devices have a limited scan range due to the optical magnification of the objective lens, which restricts high-resolution inspections.
Innovation Solution
A variable focal length lens device is designed with a beam splitter to create two branched beams, each condensed by a separate image-forming lens and captured by a distinct image sensor, allowing for different imaging distances and thus a wider scan range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical magnification of the objective lens is increased to achieve high resolution inspection, then the measurement precision is improved, but the scan range in the optical axis direction decreases
Solution Approach 1:
The patent divides the imaging function into two separate imaging paths with different imaging distances. The first image sensor captures images at a first imaging distance while the second image sensor captures images at a second imaging distance. This segmentation allows each sensor to operate at optimal imaging distances for different depth ranges, thereby expanding the overall scan range without sacrificing resolution.
Solution Approach 2:
The patent introduces a new dimension by using two different imaging distances (first imaging distance and second imaging distance) along the optical axis. This dual-distance imaging approach effectively extends the scan range in the optical axis direction by capturing focused images at multiple depth planes simultaneously or sequentially.
2Length of moving object
If a single image sensor is used to capture focused images, then the device complexity is reduced, but the scan range is limited
Solution Approach 1:
The patent makes the imaging system multi-functional by equipping it with two image sensors that can capture images at different imaging distances. This allows the single imaging optical system to perform multiple imaging functions at different depth planes, effectively expanding the scan range without requiring multiple separate imaging systems.
Solution Approach 2:
The patent creates a copy of the imaging path by introducing a second image sensor with a different imaging distance. This copied imaging path enables the system to capture focused images at a second depth plane, thereby extending the overall scan range while maintaining the same optical magnification and resolution characteristics.
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 configuration secures a wider scan range for focused images than conventional systems, even when using high-magnification objective lenses, facilitating broader inspection capabilities.
Implementation Method 1
a beam splitter configured to cause passing light to branch into a first branched beam and a second branched beam
Implementation Method 2
a refractive index of the liquid resonant lens is periodically changed in accordance with a drive signal, which causes a focusing position to periodically vary
Implementation Method 3
at least one image-forming lens configured to condense the passing light before being split by the beam splitter or condense each of the first branched beam and the second branched beam
Data Source
AI summary
A variable focal length lens device includes: a variable focal length optical system configured to change a focal length; a beam splitter configured to cause passing light, which is reflected off an object and passes through the variable focal length optical system, to branch into branched beams; an image-forming lens configured to condense the branched beams respectively; an image sensor configured to capture an image of the object by receiving the branched beam condensed by the image-forming lens; and an image sensor configured to capture an image of the object by receiving the branched beam condensed by the image-forming lens. An imaging distance on a first optical axis from the image sensor to the image-forming lens and an imaging distance on a second optical axis from the image sensor to the image-forming lens are different from each other.