Stick-like Light Guiding Member for Image Reading Device
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Solution Overview
Problem
Image reading devices that use multiple LEDs are often costly, and those employing a single high-intensity LED with a light guiding member for cost-effective solutions face challenges in maintaining accurate positioning and thermal expansion management.
Innovation Solution
An image reading device configuration featuring a light emitting portion, a stick-like light guiding member, and a holding member that positions the light guiding member along the main scanning direction, with a case member to securely hold the assembly, ensuring accurate positioning and thermal expansion management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are disposed at predetermined intervals in the main scanning direction, then illumination coverage is improved, but device cost increases
Solution Approach 1:
The illumination function is segmented between a single LED light source and a light guiding member with light emitting portions at multiple locations. The light guiding member acts as an intermediary that divides and distributes light from one source to multiple positions, achieving the effect of multiple LEDs without using multiple actual LED components.
Solution Approach 2:
A light guiding member is introduced as an intermediary component between the single LED and the document surface. This member contains multiple light emitting portions that guide and emit light at different locations, serving as a mediator that transforms single-point light emission into multi-point illumination.
2Manufacturing precision
If a light guiding member is disposed to extend in the main scanning direction, then positioning accuracy is improved, but thermal expansion management becomes difficult
Solution Approach 1:
The light guiding member is designed with flexible mounting that allows it to expand and contract thermally while maintaining its functional positioning. The holding member structure accommodates thermal dynamics by allowing movement within predetermined ranges, preventing deformation while maintaining illumination accuracy.
Solution Approach 2:
The design accounts for thermal expansion by allowing parameter changes in the physical dimensions of the light guiding member while maintaining functional parameters within acceptable ranges. The holding member is positioned at predetermined intervals to accommodate thermal parameter changes without compromising positioning accuracy.
3Quantity of substance
If a single high-intensity LED is used, then device cost decreases, but positioning precision between LED and light guiding member becomes critical
Solution Approach 1:
The holding member is designed with predetermined positioning structures that pre-establish the correct spatial relationship between the LED and light guiding member before assembly. This preliminary positioning action ensures that when components are assembled, the critical positioning precision is automatically achieved without requiring complex adjustment procedures.
Solution Approach 2:
The holding member structure provides self-positioning functionality through its predetermined interval design and geometric constraints. When the light guiding member is installed, it automatically assumes the correct position relative to the LED without requiring external alignment tools or complex positioning procedures.
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 enhances cost-effectiveness while maintaining precise positioning and distance between the LED and light guiding member, ensuring consistent performance even with thermal expansion, thus improving the device's accuracy and workability.
Implementation Method 1
a light guiding member (340) that guides light received from a light emitting portion (410)
Data Source
AI summary
The present disclosure relates to an image reading device, including: a light emitting portion; a light guiding member; a holding member that holds the light emitting portion and the light guiding member; and a case member that holds the holding member. In the image reading device, the light guiding member is shaped like a stick, of which end portion is disposed to face the light emitting portion. The holding member holds the light emitting portion and the light guiding member. In addition, the holding member has: and a holding portion that disposes the light guiding member along a main scanning direction, and positions and holds an end portion on the light emitting portion side in the main scanning direction. The case member holds the holding member.