Scanner Mirror Concavities for Edge Image Quality
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Solution Overview
Problem
Existing document scanners using multiple line sensors face challenges in maintaining image quality, particularly at the edges of the document, due to variations in document position, as existing technologies do not effectively adjust optical characteristics to compensate for these changes.
Innovation Solution
A scanner with a first mirror having concavities with varying optical characteristics, such as focal length and spatial frequency, that adjust image quality by differing these characteristics based on the document's position, ensuring better image quality at the edges by extending focal length and shifting spatial frequency distribution towards the document separation side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform optical characteristics are used across all concavities, then the device complexity is reduced, but image quality at edge positions deteriorates due to document separation
Solution Approach 1:
The patent applies local quality by making each concavity's optical characteristics (focal length, spatial frequency distribution) dependent on its specific position on the mirror surface. Edge-positioned concavities have different characteristics than center-positioned ones, optimizing image quality locally for each region while compensating for document separation effects at different positions.
Solution Approach 2:
The patent changes optical parameters (focal length, spatial frequency distribution) of the concavities based on their position. Specifically, edge concavities have longer focal lengths and shifted spatial frequency distributions compared to center concavities, allowing the system to maintain image quality across varying document positions without increasing overall device complexity.
2Reliability
If the focal length is extended at the edge side of the concavity, then image quality is maintained during document separation, but the device complexity increases
Solution Approach 1:
The patent implements local quality by assigning different focal lengths to concavities based on their position. Edge concavities have extended focal lengths specifically to compensate for document separation at edge positions, while center concavities maintain standard focal lengths, thus improving reliability locally without requiring complex adjustments across the entire system.
3Manufacturing precision
If the spatial frequency distribution shifts towards the document separation side at the edge, then image quality drops are suppressed, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the spatial frequency distribution parameter of edge concavities by shifting it toward the document separation side. This parameter change allows the system to maintain image quality consistency during document separation while the concavities are fabricated as integrated features of the mirror, making the manufacturing process manageable through standard precision machining techniques.
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 effectively suppresses image quality drops at the edges due to document separation, maintaining high spatial frequency characteristics, allowing for accurate scanning even with significant document displacement from the reference position.
Implementation Method 1
a first mirror having a plurality of concavities configured to reflect light from a document
Implementation Method 2
the optical characteristic is a focal length... the focal length at an edge side of the concavity is longer than the focal length at a center side of the concavity
Data Source
AI summary
A scanner has a first mirror having a plurality of concavities configured to reflect light from a document; and a sensor configured to detect light reflected by the concavity; the concavity having an optical characteristic that differs according to position.