Light Mixing Structures for Compact Backlight Units
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional backlight assemblies for displays with passive pixels require large mixing distances for light distribution, leading to increased volume consumption in electronic devices.
Innovation Solution
A light guide layer with a pattern of alternating light mixing structures, including triangular protrusions of varying sizes, is used to efficiently distribute light from a row of light-emitting diodes, reducing the mixing distance and minimizing volume while avoiding cross-hatched light patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light travels a sufficient distance into the light guide layer to mix enough to be used as backlight illumination, then uniform backlight illumination is achieved, but the volume consumed by the backlight unit increases
Solution Approach 1:
Light mixing structures are positioned at the input edge of the light guide layer to perform light mixing in advance, before light enters the main body of the light guide layer. This preliminary mixing action reduces the mixing distance required within the light guide layer, thereby reducing the volume consumed by the backlight unit while still achieving uniform illumination.
Solution Approach 2:
Instead of relying solely on light traveling a long distance along the light guide layer (one-dimensional mixing), the patent introduces light mixing structures at the input edge that create multiple light paths through refraction and reflection. This adds dimensional complexity to the mixing process, achieving uniform illumination more efficiently and reducing the required mixing distance.
2Volume of moving object
If light mixing structures are added to the light guide layer to reduce mixing distance, then volume is minimized, but the complexity of the light guide layer structure increases
Solution Approach 1:
The light guide layer is segmented into distinct functional regions: an input edge with light mixing structures, a main body for light transmission, and an output edge. The light mixing structures are further segmented into multiple elements with varying heights and spacing, creating a patterned structure that efficiently mixes light while maintaining manufacturing feasibility. This segmentation allows complex mixing functionality to be achieved through modular, manageable structures.
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
The solution effectively reduces the size of the display by minimizing the mixing distance while ensuring uniform backlight illumination, enhancing the compactness and efficiency of the backlight unit.
Implementation Method 1
The light mixing structures may include triangular protrusions with varying sizes. The different shaped protrusions may mix the backlight quickly without producing a cross-hatched pattern of light.
Implementation Method 2
Light from the strip of light-emitting diodes is initially concentrated in the vicinity of the outputs of the light-emitting diodes. The light must travel a sufficient distance into the light guide layer to mix enough to be used as backlight illumination.
Data Source
AI summary
A display may have a backlight unit with a row of light-emitting diodes that emit light into the edge of a light guide layer. The light guide layer may have opposing upper and lower surfaces. The upper surface of the light guide layer may have ridges and the lower surface of the light guide layer may have bumps. The edge of the light guide layer may have light mixing structures. The light mixing structures may include an alternating pattern of protrusions with different shapes. For example, triangular protrusions of a first size may be patterned with triangular protrusions of a second size. The light mixing structures may reduce the mixing distance of the backlight unit.