Rotating Image Reading Unit with Line Light Source
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Solution Overview
Problem
Conventional image reading devices face issues with unstable image quality due to reliance on environmental light, which is subject to large variations, and increased power consumption when using a light source that irradiates the entire document, leading to luminance irregularities and higher power usage.
Innovation Solution
An image reading unit with a rotation head that holds both the image reading section and light source rotatable relative to the document, allowing for controlled illumination of a specific region with line light sources, maintaining consistent distance and luminance, and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light source is provided to illuminate the entire document, then the luminance of the entire document can be ensured, but irregularity in luminance depending on a portion of the document occurs and power consumption increases
Solution Approach 1:
The patent divides the illumination task into segments by using a line light source that illuminates only the current scanning line region rather than the entire document. The illumination position is moved step-by-step along the scanning direction, so that each segment of the document is illuminated only when being scanned, reducing overall power consumption while maintaining adequate luminance for image capture.
Solution Approach 2:
The patent applies local quality by providing illumination only to the specific region being scanned at any given moment rather than uniformly illuminating the entire document. The line light source is positioned to match the scanning position, ensuring adequate luminance locally where needed while avoiding unnecessary illumination elsewhere, thus reducing power consumption.
2Illumination intensity
If a light source is provided to illuminate the entire document, then brightness of the read image can be ensured, but irregularity in reflection light occurs leading to unstable image quality
Solution Approach 1:
The patent segments both illumination and scanning into corresponding line-by-line operations. The line light source illuminates only the current scanning line, and the one-dimensional image sensor reads only that line. This segmentation ensures that illumination conditions are consistent for each scanned line, eliminating luminance irregularities that would occur with broad-area illumination and improving image quality reliability.
Solution Approach 2:
The patent employs dynamic coordination between the line light source position and the scanning position. Both the illumination position and reading position are moved step-by-step along the scanning direction in synchronization. This dynamic matching ensures that the illumination conditions remain consistent relative to the scanning position, producing stable image quality without the irregularities caused by static broad-area illumination.
3Device complexity
If environmental light is used for imaging, then device complexity is reduced, but image quality becomes unstable due to large changes in environmental light
Solution Approach 1:
The patent applies partial action by using a line light source that illuminates only the necessary scanning line region rather than the entire document. This partial illumination approach provides sufficient light for reliable image capture without requiring a complex full-document illumination system, achieving a balance between device simplicity and image quality reliability.
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 ensures consistent image quality by reducing luminance irregularities and power consumption while allowing for efficient image capture in both one-dimensional and two-dimensional directions without the need for extensive light irradiation.
Implementation Method 1
a light source that irradiates an image reading region by the image reading section with light
Implementation Method 2
a rotation head that holds the image reading section and the light source in a manner that the image reading section and the light source are rotatable relative to the document about a rotation axis which is parallel to an alignment direction of the imaging elements
Data Source
AI summary
An image reading unit includes an image reading section that reads an image of a document in a one-dimensional direction by one-dimensionally aligned imaging elements, a light source that irradiates an image reading region by the image reading section with light, and a rotation head that holds the image reading section and the light source in a manner that the image reading section and the light source are rotatable relative to the document about a rotation axis which is parallel to an alignment direction of the imaging elements.