LED Light Source With Mixing Chamber For Thin Backlight Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in handheld devices is to provide efficient coupling and mixing of light from LEDs into thin light guides, as the thickness of light guides approaches the size of LED packages, making it difficult to achieve uniform illumination and color spectrum, especially in thinner configurations where direct coupling is reduced.
Innovation Solution
A light source system featuring a light pipe with scattering centers and a mixing chamber with a wedge-shaped cavity and reflective walls, where LEDs emit light into the mixing chamber, which redirects and recycles light to improve coupling and mixing efficiency into the light pipe, even at reduced thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the light guide is reduced to achieve thinner handheld devices, then the overall device thickness is improved, but the coupling efficiency between LEDs and the light guide edge deteriorates
Solution Approach 1:
The patent introduces a reflective layer as an intermediary element positioned between the LED and the light guide edge. This reflective layer redirects light that would otherwise be lost, improving coupling efficiency into the light guide without requiring increased thickness. The reflective mediator enables effective light transfer in thin configurations where direct coupling fails.
Solution Approach 2:
The patent applies local quality by creating a light-concentrating structure at the specific location where light enters the light guide. The reflective layer is strategically positioned at the light guide edge to locally enhance light concentration and coupling efficiency, while the rest of the light guide maintains its thin profile for overall device slimness.
2Length of moving object
If the thickness of the light guide is reduced, then the device becomes thinner, but the uniformity of light distribution across the display deteriorates
Solution Approach 1:
The scattering layer acts as an intermediary that redistributes light uniformly across the light guide. By introducing this intermediate element, the patent achieves uniform light emergence from the light guide surface without increasing its thickness, resolving the contradiction between thinness and illumination uniformity.
Solution Approach 2:
The patent addresses light uniformity by introducing a new dimensional aspect through the scattering layer, which redistributes light in the lateral dimension across the light guide surface. This dimensional approach to light distribution enables uniform illumination in thin guides without relying on increased thickness.
3Length of moving object
If the thickness of the light guide is reduced, then the device becomes thinner, but the color spectrum uniformity deteriorates
Solution Approach 1:
The scattering layer serves as a mediator that randomizes light paths and ensures uniform color distribution across the light guide. This intermediate element mixes light from multiple LEDs effectively, achieving color spectrum uniformity in thin configurations where direct LED-to-light-guide coupling would produce color variations.
4Use of energy by moving object
If fluorescent lights are used to provide uniform illumination, then light output per watt-hour is improved, but the driving voltage requirement increases
Solution Approach 1:
The patent employs LEDs that inherently generate their own light without requiring high driving voltages or external ballast circuits. The LED-based system with reflective and scattering layers achieves efficient light generation and distribution, eliminating the high voltage requirements of fluorescent lights while maintaining energy efficiency.
5Illumination intensity
If fluorescent tubes are placed behind the LCD display, then high light output is achieved, but the display thickness increases
Solution Approach 1:
The patent replaces bulky fluorescent tubes with compact LED packages that provide equivalent or superior light output in a much thinner form factor. The LED-based illumination system with reflective and scattering layers achieves high light output without the thickness penalty of fluorescent tube technology.
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 solution enhances light mixing and coupling efficiency, ensuring uniform illumination and color spectrum, even in thin light guides, by redirecting and recycling light within the mixing chamber, thereby addressing the limitations of direct coupling in thin configurations.
Implementation Method 1
The light pipe includes light pipe scattering centers that cause light traveling in the sheet of transparent material to be scattered in directions that allow some of the scattered light to escape the sheet of transparent material through the top surface
Implementation Method 2
The mixing chamber includes mixing chamber scattering centers for redirecting light traveling in the cavity in directions that would not be obtained by reflection from the reflective walls
Implementation Method 3
A portion of the light in the cavity is directed into the light pipe at angles at which that light will be reflected from the top and bottom surfaces of the sheet of transparent material back into the sheet of transparent material
Data Source
AI summary
A light source having a light pipe and a light generation section. The light pipe includes a two-dimensional sheet of transparent material having a transparent top surface that is substantially parallel to a reflective bottom surface. The light pipe includes light pipe scattering centers that cause light traveling in the sheet of transparent material to be scattered in directions that allow some of the scattered light to escape the sheet through the top surface. The light generating section includes a plurality of LEDs and a mixing chamber. The LEDs are positioned to emit light into the mixing chamber. The mixing chamber includes an adapter having a wedge-shaped cavity with reflective walls. The cavity has an opening positioned to direct light into the light pipe. The mixing chamber includes scattering centers for redirecting light traveling in the cavity in directions that would not be obtained by reflection from the reflective walls.