Light Guide Illumination Apparatus Uniformity
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Solution Overview
Problem
Existing light-guide type illumination systems face challenges in achieving uniform light emission along the longitudinal direction, particularly when light enters from a direction different from the longitudinal direction, leading to leakage and uneven illuminance.
Innovation Solution
The design incorporates a light guide with a curved and linear portion, where the light is reflected and diffused through an inclined portion to increase the incident angle, allowing uniform light emission along the main-scan direction, reducing unique light generation and local luminance unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a light guide with an inclined surface is used to reflect light entered from a direction different from the longitudinal direction, then the light can be propagated in the longitudinal direction, but light leakage occurs around the inclined surface causing non-uniform illuminance
Solution Approach 1:
The light guide is divided into multiple sections: a first light guide section with the inclined surface for reflecting light from different directions, and a second light guide section with a light blocking member to prevent light leakage. This segmentation allows each section to perform its specific function optimally.
Solution Approach 2:
A light blocking member is introduced as an intermediary element within the light guide structure. This member blocks light that would otherwise leak through the inclined surface, preventing illuminance non-uniformity while maintaining the light guide's ability to accept light from various directions.
2Manufacturing precision
If a dedicated light source is used to provide light on the end face in the longitudinal direction of the light guide, then uniform light emission is achieved, but the cost increases
Solution Approach 1:
The light guide structure is designed to work with general, inexpensive surface-mount light sources rather than requiring dedicated expensive light sources. The inclined surface and light blocking member enable the light guide to adapt to standard light sources while maintaining uniform light emission characteristics.
Solution Approach 2:
The light guide structure modifies the light path parameters through the inclined surface and light blocking member configuration, enabling standard light sources to achieve uniform light emission that would otherwise require specialized expensive light sources.
3Ease of operation
If light is reflected in the longitudinal direction of the light guide based on the inclined surface, then light propagation is achieved, but local luminance unevenness occurs
Solution Approach 1:
The harmful light leakage is extracted and blocked by the light blocking member positioned within the light guide structure. This removes the source of luminance unevenness while preserving the beneficial light reflection and propagation functions of the inclined surface.
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 ensures uniform light emission and reduces local luminance unevenness, even when reading partially floating originals, thereby improving image quality by minimizing directivity-related issues.
Implementation Method 1
light emitted by a light source provided on an end face in a longitudinal direction of a light guide formed in a rod shape is reflected and diffused in the light guide and propagated through the light guide
Implementation Method 2
light emitted by a light source provided on an end face in a longitudinal direction of a light guide formed in a rod shape is reflected and diffused in the light guide
Data Source
Figure 1
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AI summary
Provided are: a light source (19) that emits light; a light guide (30) including: a curved portion (31) including a light incident surface (32) from which the light from the light source (19) enters; and a linear portion (36) including a light emission surface (38) from which the light is emitted to an original, the linear portion (36) coupled to the curved portion (31) and extended in a main-scan direction, the curved portion (31) reflecting the light entered from the light incident surface (32) to the linear portion (36); and a frame (11) that houses the light source (19), and the light guide (30), wherein the light guide (30) includes an inclined portion (41) inclined in a direction that increases an incident angle β of the light, the inclined portion (41) formed in a range of the linear portion (36) where the light reflected by the curved portion (31) enters.