Light Guide Stepped Portion Shielding for Optical Stability
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Solution Overview
Problem
Existing image scanning devices with light guides face increased complexity in manufacturing due to the need for additional components, such as metal tubes or light-shielding members, which complicate the installation and maintenance of the illumination system.
Innovation Solution
The image scanning device incorporates a linear light source with a rod-like transparent light guide, a scatterer, an emitter, a stepped portion, and a light-shielding member that covers the emitter, ensuring stable optical properties without adding complexity by using a molded light-shielding member that extends beyond the sensor's scan range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal tube is used to cover the stepped end portion of the light guide, then the optical properties at the end portion are stabilized, but the device complexity increases due to additional components and installation steps
Solution Approach 1:
The light-shielding member is integrated into the light guide body itself, forming a unified structure where the light guide and light-shielding function are combined in a single component. This eliminates the need for separate metal tubes or additional light-shielding components, thereby reducing device complexity while maintaining optical stability.
Solution Approach 2:
The light guide body serves multiple functions: it guides light along the main scan direction and simultaneously provides light-shielding at its end portion through the integrated light-shielding member. This multi-functionality reduces the need for separate components, addressing the contradiction between reliability and device complexity.
2Reliability
If a light-shielding member is installed at the light guide body, then the optical properties are improved, but the manufacturing process complexity increases
Solution Approach 1:
The light-shielding member and light guide body are formed as a single integrated component through molding, eliminating separate manufacturing steps for assembling light-shielding members. This integration simplifies the manufacturing process while ensuring stable optical properties at the light guide end portion.
Solution Approach 2:
The light-shielding member is formed as an integral part of the light guide body during the molding process, rather than being added as a separate component afterward. This preliminary integration simplifies manufacturing by combining multiple functions into a single production step.
3Reliability
If the light-shielding member extends beyond the stepped portion, then the optical properties at the end portion are more stable, but the device complexity increases
Solution Approach 1:
The extended light-shielding member is integrated into the light guide body structure, creating a unified component that provides both light guiding and light-shielding functions. This integration maintains optical stability without adding separate components or increasing overall device complexity.
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 provides stable optical properties at the end portion of the light guide, reducing manufacturing complexity and maintaining efficient illumination without the need for additional components, thus enhancing the device's performance and reliability.
Implementation Method 1
a light guide (21) which is a rod-like transparent body extending along a main scan direction of the sensor (4), and guides, in the main scan direction, light entering the light guide (21) through an end surface
Implementation Method 2
a scatterer (22) which is formed along the main scan direction on a surface of the light guide (21) that is opposite to an illumination position side of the light guide (21), and scatters light
Implementation Method 3
an emitter (23) which is formed along the main scan direction on a surface of the light guide (21) between the scatterer (22) and the illumination position and emits the light scattered by the scatterer (22) to the illumination position
Data Source
AI summary
An image scanning device includes a linear light source to illuminate a linear illumination position of a scan target with light, a lens body, and a sensor. The linear light source includes a light guide, a scatterer, an emitter, a stepped portion, and a light-shielding member. The stepped portion is formed, from the end surface of the transparent body along the main scan direction, on a side of the light guide that is opposite to the illumination position side of the light guide. The light-shielding member covers a portion of the emitter of the light guide, the portion including the end surface of the transparent body, and extends beyond the stepped portion in the main scan direction and has an end portion that is located out of a scan range of the sensor in the main scan direction.