Negative Spherical Aberration Lens Assembly for Extended Working Range
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Solution Overview
Problem
Existing imaging lens assemblies in electro-optical readers have a limited working range and relatively slow data capture, making them less effective in applications requiring rapid data capture and extended working range.
Innovation Solution
An imaging lens assembly incorporating a negative spherical aberration component and an aperture stop, positioned close together, is used to focus both on-axis and off-axis illumination light onto a solid-state imager, extending the working range and improving data capture efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional imaging lens assembly is used, then the reader can capture images, but the working range is limited and data capture is slow
Solution Approach 1:
The lens assembly is divided into multiple discrete optical elements including a positive meniscus lens, negative meniscus lens, positive plano-convex lens, and negative spherical aberration component. Each element performs a specific function in the optical path, allowing independent optimization of focal length, aberration correction, and depth of field to achieve both extended working range and rapid data capture
Solution Approach 2:
Each lens element is designed with specific local optical properties: the positive meniscus lens provides converging power, the negative meniscus lens corrects spherical aberration, the positive plano-convex lens focuses light, and the negative spherical aberration component specifically addresses off-axis aberrations. This localized optimization of optical quality at different positions in the assembly enables simultaneous achievement of extended working range and high-speed capture
2Reliability
If the working range is extended, then more distances can be read, but image quality and contrast may deteriorate
Solution Approach 1:
The lens assembly employs asymmetric lens designs including positive and negative meniscus lenses with different curvature radii on each surface. The positive meniscus lens has a first curvature radius on its first surface and a second curvature radius on its second surface, creating asymmetric light bending that optimizes focus across the extended working range while maintaining image quality through careful balancing of optical paths
Solution Approach 2:
The optical system utilizes precise parameter specifications for each lens element including curvature radii (e.g., first curvature radius, second curvature radius), thicknesses, and material refractive indices. By carefully controlling these optical parameters, the system maintains high image quality and contrast across the extended working range from close to far distances
3Measurement precision
If multiple lenses are used to improve focusing, then image quality improves, but the device becomes more complex
Solution Approach 1:
The patent combines multiple optical functions into a coordinated lens assembly where the positive meniscus lens, negative meniscus lens, positive plano-convex lens, and negative spherical aberration component work together as an integrated system. This merging of elements achieves superior image quality through complementary optical actions while maintaining a compact, manageable assembly structure
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 increases the working range by approximately 40% while maintaining high-contrast, readable images, and eliminates stray light and chromatic aberrations, enhancing the reader's performance in low-light environments.
Implementation Method 1
an imaging lens assembly incorporating a negative spherical aberration component and an aperture stop, positioned close together, is used to focus both on-axis and off-axis illumination light onto a solid-state imager, extending the working range
Implementation Method 2
an imaging lens assembly incorporating a negative spherical aberration component and an aperture stop, positioned close together, is used to focus both on-axis and off-axis illumination light onto a solid-state imager
Implementation Method 3
eliminates stray light and chromatic aberrations, enhancing the reader's performance in low-light environments
Data Source
AI summary
An imaging lens assembly focuses light from indicia in a working range of distances along an optical path onto a solid-state imager of an imaging reader. The lens assembly includes a negative spherical aberration component and an aperture stop that together are operative for extending the working range.