Variable Thickness Light Guide for High Luminance Sidelight Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Illumination devices with a sidelight structure face challenges in achieving high luminance due to lower light output efficiency compared to direct-below structures, and varying light guide thickness affects the emission angle and luminance.
Innovation Solution
The illumination device employs a configuration with two light guides of varying thickness, featuring projection portions that alter the light reflection angle, and a prism sheet to ensure uniform light emission, achieving high luminance and consistent light quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a sidelight structure with light sources on the side surface of a light guide is used, then the device can be compact, but the light output efficiency and luminance are reduced
Solution Approach 1:
The light guide is designed with varying thickness: thicker at the light source side to maintain compactness and thinner at the emission side to enhance luminance. This local variation in thickness optimizes both the compactness and brightness performance by adapting the light guide structure to different functional requirements at different locations.
Solution Approach 2:
Instead of improving luminance by increasing light source power in the same dimension, the invention transitions to a different dimension by varying the light guide thickness. This dimensional change allows the light to travel through a longer path in the thick region and emit more efficiently in the thin region, achieving high luminance while maintaining compactness.
2Illumination intensity
If the light guide thickness is increased to improve light output efficiency, then more light can be extracted, but the emission angle varies and luminance becomes non-uniform
Solution Approach 1:
The light guide employs non-uniform thickness distribution: thicker near the light source for efficient light extraction and thinner near the emission surface for uniform luminance. This local quality variation ensures that each region of the light guide is optimized for its specific function, achieving both high light output efficiency and uniform emission.
Solution Approach 2:
The invention changes the thickness parameter of the light guide along its length, transitioning from a constant thickness design to a variable thickness design. This parameter change allows optimization of light extraction efficiency in the thick region while controlling emission uniformity in the thin region, resolving the contradiction between light output efficiency and emission uniformity.
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 light output efficiency and achieves high luminance with uniform light distribution across the irradiating surface, even with thicker light guides, overcoming the limitations of sidelight structures.
Implementation Method 1
a first illumination element comprising a first light guide and a plurality of first light source elements provided on a first side surface of the first light guide
Implementation Method 2
a plurality of first projection portions provided on a first main surface of the first light guide
Data Source
AI summary
According to one embodiment, in an illumination device, a plurality of first projection portions and a plurality of second projection portions are provided in a second area of a first light guide, a thickness of the first light guide becomes less as a location thereof which is further away from a first side surface and closer to a first central portion, a plurality of third projection portions and a plurality of fourth projection portions are provided in a third area of a second light guide, and the third area has a constant thickness and a fourth area of the second light guide is a recess portion.