Illumination Apparatus Light Guide Condensing Action
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Solution Overview
Problem
Existing image reading apparatuses face challenges in achieving high illumination efficiency and maintaining a compact size due to insufficient light condensation in the sub-scanning direction, particularly when dealing with uneven original surfaces, leading to degraded reading performance.
Innovation Solution
The proposed illumination apparatus employs a light guide with a convex first exit surface and a second exit surface, both having condensing actions in the orthogonal plane to the light source direction, combined with a reflecting member to ensure efficient light distribution from both sides, enhancing illumination efficiency while maintaining a lower-profile design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the incident surface is formed in a convex shape to have a condensing action, then light condensation is improved, but only light within a small angle range enters the light guide, resulting in poor illumination efficiency
Solution Approach 1:
The light guide is divided into two functional parts: the incident surface with convex shape for light condensation, and the exit surfaces with concave shape for light distribution. This segmentation allows each part to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different surfaces of the light guide are given different shapes and optical properties: the incident surface is convex for condensation, while the exit surfaces are concave for distribution. This local differentiation of geometric quality enables simultaneous achievement of light condensation and efficient illumination.
2Productivity
If the incident surface size is increased to capture more light, then illumination efficiency is improved, but the device size increases, contradicting the downsizing requirement
Solution Approach 1:
The light guide surfaces are designed with curved shapes (convex and concave) that provide optical condensation and distribution functions. These curved geometries enable effective light control within a compact volume, achieving high illumination efficiency without requiring a large incident surface area.
3Volume of moving object
If reduction magnification is decreased to achieve smaller size, then device compactness is improved, but sensor surface experiences insufficient illuminance, requiring brighter illumination
Solution Approach 1:
The light guide introduces a new optical dimension by using curved surfaces that control light propagation in multiple directions. The convex incident surface condenses light from the light source, while the concave exit surfaces distribute it uniformly across the sensor area, achieving high illuminance in a compact device.
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 significantly improves light condensing efficiency in the sub-scanning direction, ensuring sufficient illumination on the original surface, even with uneven surfaces, and allows for the downsizing of the illumination apparatus while maintaining high image reading performance.
Implementation Method 1
a side surface for totally reflecting a portion of the light beam which enters the incident surface
Implementation Method 2
a first exit surface for causing a light beam reflected by the reflecting surface to exit as a converging light beam, the first exit surface having a condensing action in a plane orthogonal to the one-dimensional direction
Implementation Method 3
a second exit surface for causing a light beam from the light source, which is not reflected by the reflecting surface, to exit as a converging light beam, the second exit surface having a condensing action in the plane orthogonal to the one-dimensional direction
Data Source
AI summary
An illumination apparatus configured to illuminate a target surface from a first side and a second side different from the first side, including: a guide; and a reflector, the guide including: incident surface; a surface for totally reflecting beam from the incident surface; a reflecting surface arranged on an opposite side of the incident surface relative to the surface; a first exit for causing the reflected beam to exit as converging beam from the first side, the first exit having condensing action in plane orthogonal to the one-dimensional direction; and a second exit, adjacent to the first exit, having condensing action in the orthogonal plane for causing beam not reflected by the reflecting surface to exit as converging beam, and the reflector reflecting the beam from the second exit to the target surface as beam from the second side.