Optical Line Sensor Lens Array for Deep Depth of Field
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Solution Overview
Problem
Existing optical line sensors face challenges with short operation distance, shallow depth of field, and complexity in manufacturing, leading to high costs and susceptibility to environmental changes, while refractive optical systems are large and prone to optical unevenness and missing pixels.
Innovation Solution
An optical line sensor with a simple refractive system design, featuring separated light-receiving lenses and elements, arranged to avoid overlapping visual fields and increased focal length, ensuring a long operation distance and deep depth of field, and using a reduction optical system to enhance resolution and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a telecentric optical system using a mirror optical system is used to achieve deep depth of field, then depth of field is improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent divides the optical system into multiple separated light-receiving lenses arranged in an array, each with its own light-receiving element. This segmentation allows achieving deep depth of field through proper spacing and arrangement without requiring complex telecentric mirror systems, thereby reducing overall device complexity while maintaining manufacturing precision.
Solution Approach 2:
The patent replaces the mechanical mirror-based telecentric optical system with a simpler refractive lens system. By using separated light-receiving lenses with appropriate spacing (at least the diameter of one lens apart), the system achieves telecentric-like performance without the complexity of mirror alignment and mechanical adjustment, reducing device complexity while maintaining depth of field.
2Length of moving object
If a refractive lens system is used to increase operation distance, then operation distance is improved, but depth of field becomes shallow
Solution Approach 1:
The patent uses multiple separated light-receiving lenses arranged in an array rather than a single lens. This segmentation allows each lens to contribute to a specific portion of the field of view, enabling the system to achieve both long operation distance and deep depth of field simultaneously by combining the effects of multiple lenses with appropriate spacing.
Solution Approach 2:
The patent transitions from a single-lens approach to a multi-lens array configuration, adding spatial arrangement as an additional dimension for controlling optical performance. By carefully arranging lenses at specific separations (at least one lens diameter apart) and pairing them with corresponding light-receiving elements, the system achieves both long working distance and deep depth of field through dimensional optimization.
3Volume of moving object
If lenses are arranged close together to compact the device, then device size is reduced, but crosstalk between lenses occurs and missing pixels appear
Solution Approach 1:
The patent segments the optical field by ensuring each light-receiving lens is separated from adjacent lenses by at least its own diameter. This segmentation creates distinct optical zones for each lens-element pair, preventing crosstalk between adjacent channels and avoiding missing pixels, while still maintaining a compact overall device structure through the systematic arrangement of separated units.
Solution Approach 2:
The patent applies local quality control by assigning specific functional characteristics to each lens-element pair in the array. Each separated lens is optimized for its local field of view, and the spacing ensures that each local optical channel operates independently without interference from neighbors, maintaining reading completeness while achieving compactness through localized optimization.
4Ease of manufacture
If a simple refractive optical system is used to reduce manufacturing complexity, then ease of manufacture is improved, but optical uniformity and resistance to environmental changes deteriorate
Solution Approach 1:
The patent uses multiple separated light-receiving lenses in an array configuration, where each lens-element pair operates as an independent modular unit. This segmentation provides inherent redundancy and stability, as environmental variations affecting one lens are localized and do not propagate across the entire system, maintaining optical uniformity and environmental resistance while keeping manufacturing simple through standardized modular components.
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 achieves a compact, durable, and high-resolution optical line sensor with improved depth of field and dynamic range, reducing manufacturing complexity and environmental sensitivity, and minimizing optical unevenness.
Implementation Method 1
a new refractive system lens having long W.D. and a deep depth of field
Implementation Method 2
A plurality of the light-receiving elements are arranged linearly along the main scanning direction, and receive light transmitted through a plurality of the light-receiving lenses
Data Source
AI summary
An optical line sensor reads an inspection object conveyed in a sub-scanning direction by a reading line L extending in a main scanning direction and includes a plurality of light-receiving lenses 11 and a plurality of light-receiving elements. The plurality of light-receiving lenses 11 are arranged along the main scanning direction. The plurality of light-receiving elements are arranged linearly along the main scanning direction, and receive light transmitted through the plurality of light-receiving lenses 11. The plurality of light-receiving lenses 11 are arranged to be separated from each other by a diameter of the light-receiving lens 11 or longer. A plurality of light-receiving elements 121 form at least one row or more of the reading lines L.