Telecentric Cell Array for Large Depth of Field in Image Scanners
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Solution Overview
Problem
Conventional image reading apparatuses face challenges in achieving a large depth of field while maintaining a compact size and minimizing chromatic aberration, with existing systems either being bulky, costly, or suffering from image displacement issues due to varying transfer magnification and focus position changes.
Innovation Solution
An image reading apparatus with a telecentric optics system arranged in two rows of cells in the sub-scanning direction, where each cell has a telecentric optics system at the document side, allowing for parallel chief rays and a transfer magnification of 1, enabling image reconstruction and combination without distortion, even when the document moves in focus direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-eye lens system is used to achieve a large depth of field, then the document can be read even when not in close contact with the reading surface, but the optics system becomes large and requires expensive control of multiple mirrors
Solution Approach 1:
The patent divides the imaging system into multiple independent cells arranged in two rows, where each cell contains its own imaging optics and image pickup device. This segmentation allows each cell to have a telecentric optics system with a relatively simple structure, while the collective array achieves the required depth of field through the two-row configuration that complements images in the sub-scanning direction.
Solution Approach 2:
The patent introduces a two-row arrangement of cells in the sub-scanning direction, adding a dimensional aspect to the imaging system. By arranging cells in two rows and using zigzag arrangement in the main scanning direction, the system achieves depth of field extension without requiring a single complex large-scale optics system, thus reducing overall device complexity while maintaining reliability.
2Reliability
If conventional optics systems are used to achieve large depth of field, then image reading is possible without close contact, but chromatic aberration increases and apparatus size increases
Solution Approach 1:
By segmenting the imaging system into multiple independent cells, each with its own telecentric optics system, the patent reduces chromatic aberration in each individual cell while maintaining overall depth of field through the two-row array configuration.
Solution Approach 2:
Each cell is designed with local telecentric optics system that optimizes image quality and minimizes chromatic aberration for its specific imaging region, while the collective arrangement maintains the required depth of field across the entire document area.
3Reliability
If conventional optics systems are used to achieve large depth of field, then contactless reading is possible, but the apparatus size becomes large
Solution Approach 1:
The patent segments the imaging system into multiple compact cells arranged in a two-row configuration, where each cell has a relatively small telecentric optics system. This segmentation allows the overall apparatus to achieve large depth of field through the array configuration rather than requiring a single large optics system, thus reducing total apparatus volume.
Solution Approach 2:
By arranging cells in two rows in the sub-scanning direction and using zigzag arrangement in the main scanning direction, the patent achieves depth of field extension through spatial configuration rather than increasing the size of individual optics components, thereby maintaining compact apparatus dimensions.
4Manufacturing precision
If telecentric optics system with two rows of cells is used, then image quality and depth of field are improved, but device complexity increases
Solution Approach 1:
The patent divides the high-precision imaging task into multiple independent cells, each with a telecentric optics system that ensures high image quality for its region. The two-row arrangement with zigzag configuration in the main scanning direction allows for systematic assembly and alignment, managing device complexity through modular design while maintaining manufacturing precision.
Solution Approach 2:
Each cell is designed with local telecentric optics system that optimizes image quality and minimizes aberrations for its specific imaging region. The standardized cell design with consistent optical paths and the two-row arrangement pattern simplify manufacturing and assembly processes, balancing device complexity with image quality requirements.
5Device complexity
If conventional image reading systems are used, then simple optics are used, but image displacement occurs due to varying transfer magnification and focus position changes
Solution Approach 1:
Each cell is designed with a telecentric optics system that maintains constant transfer magnification regardless of focus position changes. The telecentric design ensures that chief rays are parallel to the optical axis, eliminating perspective distortion and image displacement that occur in conventional systems, thereby maintaining image position stability while using relatively simple optics in each cell.
Solution Approach 2:
By dividing the imaging system into multiple independent telecentric cells, the patent ensures that each cell maintains stable image positioning for its region. The two-row arrangement with zigzag configuration allows for systematic image combination that maintains overall image position stability, preventing displacement issues that would occur in conventional single-system approaches.
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 allows for a high-quality image with a large depth of field, reduced apparatus size, and minimized chromatic aberration, while using existing image pickup device resolution, and effectively addresses the issues of image displacement and cost associated with complex optics systems.
Implementation Method 1
an imaging optics system for forming an image on condensing scattered light of light reflected by the section
Implementation Method 2
an imaging optics system for forming an image on condensing scattered light of light reflected by the section
Implementation Method 3
each cell having a telecentric optics system at a document side
Data Source
Figure 1
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Figure 4~5
AI summary
An image reading apparatus includes a light source (2), an imaging optics system (1), an image pickup device unit (41; 42,..), a memory (5), and a processor (6). The imaging optics system is an optics system for condensing scattered light reflected on an object to be imaged to form such condensed light as an image. The imaging optics system has a plurality of cells (11, 12,..) and the like which are arranged in a main scanning direction (211) and each of which is an independent imaging optics system. Each of the cells (11, 12,..) has a telecentric optics system at the side of the document. Two rows of cells are arranged in a sub-scanning direction (212). The cells (11, 12,..) in the rows are arranged zigzag in the main scanning direction so as to be able to complement a formed image by the cells in the sub-scanning direction (212). The image pickup device unit (41, 42,..) is arranged to correspond to each cell. The processor (6) can form a document image by reconstructing and combining image information stored in the memory (5) into an image.