Light Guide Extraction Layout for Uniform Long-Distance Luminance
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Solution Overview
Problem
In illumination devices with a light guide layer and a light source emitting light toward a side surface, luminance decreases with increasing distance from the light source.
Innovation Solution
A light guide member with a first region having a light extraction structure and a second region without, where the first region's length in the light guide direction is 350 mm or more, and the ratio of its width to the light guide layer's width is between 30% and 100%, featuring internal spaces for light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If light enters from the side surface into the light guide layer, then the light guide layer can guide light over long distances, but luminance decreases with increasing distance from the light source
Solution Approach 1:
The light guide layer is divided into a first region with light extraction structure and a second region without light extraction structure. This segmentation allows light to be extracted at specific zones along the light guide direction, maintaining luminance over long distances by preventing excessive light propagation that would cause luminance decay.
Solution Approach 2:
Different regions of the light guide layer are given different properties: the first region has a light extraction structure with specific geometric features (internal spaces, protrusions, or recesses) to extract and diffuse light locally, while the second region maintains pure light guiding properties. This local differentiation optimizes both light guidance distance and luminance distribution.
2Illumination intensity
If light extraction structure is added to the light guide layer, then luminance distribution is improved, but device complexity increases
Solution Approach 1:
The light extraction structure is integrated directly into the light guide layer as a unified component rather than being a separate element. The light extraction structure consists of geometric features (internal spaces, protrusions, or recesses) formed within the light guide layer material itself, combining the light guiding and light extracting functions in a single structure.
Solution Approach 2:
The light extraction structure utilizes internal spaces within the light guide layer that create a porous-like configuration. These internal spaces serve as light extraction zones where light can escape from the light guide layer, providing effective light extraction without requiring complex external optical components.
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
Reduces the decrease in luminance with increasing distance from the light source, enhancing luminosity distribution.
Implementation Method 1
the light extraction structure has a plurality of internal spaces configured to extract light by total internal reflection
Data Source
Figure 1A
Figure 1B~2
Figure 3A~3C
AI summary
A light guide member (110A) includes: a light guide layer (10) having a first main surface (10m), a second main surface (10n) at an opposite side from the first main surface, and a light receiving portion (10s1) configured to receive light emitted from a light source (LS); and a light extraction structure configured to extract a portion of light propagated in the light guide layer (10) from the first main surface or the second main surface. The light guide member (110A) has a first region (R1) in which the light extraction structure is present, and a second region (R2) in which the light extraction structure is not present, in a plan view from a normal direction of the first main surface. A length of the first region (R1) in a first direction parallel to a light guide direction of the light guide layer is 350 mm or more. A ratio Wb/Wa of a length Wb of the first region (R1) in a second direction crossing the first direction to a length Wa of the light guide layer in the second direction is more than 30% and less than 100%.