Integrated LED Backlight Unit with Transparent Optical Launch
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Solution Overview
Problem
Conventional LED backlight solutions suffer from optical losses due to absorptive losses in the LED package, etendue limitations in coupling optics, assembly tolerances, and the desire for thinner display designs, particularly in mobile digital appliances.
Innovation Solution
An integrated back light unit architecture where a light emitting diode (LED) assembly with a support having an interstice is encapsulated in a transparent material forming an optical launch and/or waveguide, directly coupled to a back light waveguide, eliminating first-level packaging and associated optical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional LED units are fabricated by mounting LEDs to a substrate and optically coupling them to a waveguide, then the LEDs are securely mounted and electrically connected, but poor optical coupling occurs due to absorptive losses in the LED package and etendue limitations
Solution Approach 1:
The patent merges the LED mounting substrate and the optical waveguide into a single integrated structure. The waveguide is formed directly on the substrate containing the LED interstices, eliminating the separate optical coupling component. This integration removes the optical interfaces between the LED package, coupling optics, and waveguide, thereby eliminating absorptive losses and etendue limitations while reducing overall device complexity.
Solution Approach 2:
The patent extracts and eliminates the first-level LED packaging structure that causes absorptive losses. By mounting LEDs directly to the substrate without traditional encapsulation and then integrating the waveguide directly to the substrate, the harmful packaging layers are removed from the optical path, improving optical coupling efficiency.
2Manufacturing precision
If traditional LED packaging is used with multiple optical interfaces, then the LEDs are protected and electrically connected, but assembly tolerances and alignment precision deteriorate
Solution Approach 1:
The substrate serves dual functions as both the electrical mounting platform for LEDs and the optical waveguide structure. This merging eliminates the need for separate alignment steps between LED packages and waveguides, as they are inherently aligned through the integrated substrate structure, improving manufacturing precision while simplifying the assembly process.
3Length of moving object
If conventional LED units with separate waveguide coupling are used, then the optical coupling can be implemented, but the backlight unit thickness increases
Solution Approach 1:
The waveguide is integrated directly onto the LED substrate, eliminating the need for separate optical coupling components and intermediate layers. This integration dramatically reduces the overall backlight unit thickness while maintaining effective optical coupling, as the waveguide is in direct contact with the LED light sources without intervening optical interfaces that would cause energy losses.
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 optical coupling efficiency, reduces power consumption, and allows for thinner backlight units by eliminating undesirable optical interfaces and improving alignment tolerances, resulting in improved light guiding and reduced manufacturing complexity.
Implementation Method 1
an optical waveguide optically coupled to the optical launch
Implementation Method 2
an index matching compound located between the optical launch and the back light waveguide
Implementation Method 3
a circumferential polarizer located around the back light waveguide to reduce light loss from an optical hot spot in the back light waveguide
Data Source
AI summary
A light emitting device includes a support having an interstice and at least one LED located in the interstice and at least one of a waveguide or an optical launch having a transparent material encapsulating the at least one LED located in the interstice.