Light Source Device Uniform Illumination via Segmented Guides
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Solution Overview
Problem
Conventional light source devices for document irradiation, such as those described in Japanese Patent Laid-Open Publication No. 2002-185708, suffer from varying light intensity and chromaticity along the light guide, leading to reduced color reproducibility in image reading applications.
Innovation Solution
A light source device comprising a light source, first and second light guides, and a confinement portion with reflection surfaces that confine and reflect light emitted by the source, ensuring consistent intensity and chromaticity across the document irradiation area, using a housing with specular finish or white paint to maintain light within the guides and equalize beam intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light is guided through a single light guide from one end to the other, then the number of light sources can be reduced, but light intensity and chromaticity vary along the light guide
Solution Approach 1:
The patent divides a single long light guide into multiple separate light guides (first light guide and second light guide). Each light guide receives light from the same light source but has a limited length, ensuring that light intensity and chromaticity remain uniform along each guide. This segmentation resolves the contradiction by maintaining manufacturing simplicity (still using one light source) while achieving uniform illumination across all guides.
2Device complexity
If light enters from one end of a light guide, then the structure is simple, but intensity and chromaticity vary between light from one end and light from the other end
Solution Approach 1:
By segmenting the single long light guide into multiple shorter light guides, the patent maintains simple entry structures (light enters from one end of each guide) while ensuring chromaticity consistency within each guide. The multiple guides collectively provide uniform chromaticity across the entire illumination area, resolving the contradiction between structural simplicity and chromaticity consistency.
3Manufacturing precision
If multiple light guides are used to ensure uniform light distribution, then color reproducibility improves, but the device complexity increases
Solution Approach 1:
The patent combines multiple light guides with a single light source and confinement portion, creating an integrated system. The confinement portion serves all light guides simultaneously, and the guides work together to provide uniform illumination. This merging approach achieves good color reproducibility while minimizing device complexity compared to using multiple independent light sources or complex distribution systems.
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 superior color reproducibility and high light use efficiency, reducing intensity differences and preventing uneven illuminance distribution, thereby enhancing image quality in image reading apparatuses.
Implementation Method 1
the light confined in the confinement portion is reflected off both first and second reflection surfaces provided in the confinement portion, and thereby travels through the first and second light guides in the first predetermined direction
Data Source
AI summary
A light source device having: a light source; first and second light guides extending in a first predetermined direction to guide light in the first predetermined direction and irradiate a document with the light; and a confinement portion that confines light emitted by the light source and is connected to one end of the first light guide and one end of the second light guide, in which the light confined in the confinement portion is reflected off both first and second reflection surfaces provided in the confinement portion, and thereby travels through the first and second light guides in the first predetermined direction.