Backlight Waveguide with V-Shaped LED Opening and Reflector
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Solution Overview
Problem
Existing backlight technologies for displays, particularly LCDs, face challenges in achieving uniform light distribution with a high number of LEDs, which increases cost and thickness, and existing side-emitting LEDs are less efficient compared to top-emitting LEDs.
Innovation Solution
The use of a transparent waveguide with top-emitting LEDs positioned near the edge, featuring a V-shaped opening to refract light and a reflector to redirect light into the waveguide, along with virtual light sources created by empty openings coated with reflective materials, reduces the number of LEDs required while maintaining uniformity and light mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a high number of LEDs are used to achieve uniform light distribution, then illumination uniformity is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates virtual light sources by placing reflective materials in empty openings of the waveguide. These virtual sources are optical copies that reflect and redirect light paths, effectively multiplying the light distribution capability without adding physical LEDs. This resolves the contradiction by achieving uniform illumination through optical copying rather than increasing the actual number of light-emitting components.
Solution Approach 2:
The patent introduces reflective materials as intermediary elements between the light sources and the waveguide interior. These intermediaries (reflective coatings in openings) mediate light distribution by redirecting light paths, creating virtual sources that enhance uniformity without requiring additional LEDs. The intermediary reflective surfaces enable uniform illumination while maintaining a reduced number of actual light-emitting devices.
2Illumination intensity
If more LEDs are used to improve light distribution, then illumination uniformity is improved, but device thickness increases
Solution Approach 1:
By creating virtual light sources through reflective materials in the waveguide openings, the patent achieves enhanced light distribution uniformity without adding physical thickness. The virtual sources are optical illusions created by light reflection, not physical objects that would increase device dimensions. This allows uniform illumination to be achieved while maintaining a thin profile.
3Ease of manufacture
If side-emitting LEDs are used, then ease of integration is improved, but light emission efficiency deteriorates
Solution Approach 1:
The patent inverts the conventional side-emitting LED approach by using top-emitting LEDs combined with reflective materials in waveguide openings. Instead of emitting light from the sides, the system uses top-emitting LEDs whose light is redirected by reflective surfaces to create uniform distribution. This inversion resolves the contradiction by achieving both efficiency (through top-emitting LEDs) and uniformity (through reflective redirection).
Solution Approach 2:
The reflective materials serve as intermediaries that convert the directional output of top-emitting LEDs into uniform omnidirectional distribution. The intermediaries (reflective coatings) enable top-emitting LEDs to achieve the uniform light distribution previously only possible with side-emitting configurations, thereby maintaining ease of integration while dramatically improving light emission efficiency.
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 allows for a reduction in the number of LEDs needed, minimizing cost and thickness while ensuring sufficient and uniform light distribution, even in larger displays like computer monitors or televisions.
Implementation Method 1
The first opening has a first portion closer to the edge than a second portion. The second portion is curved. According to the invention the first portion of the first opening is V-shaped to refract light towards the edge.
Implementation Method 2
In some embodiments, a reflector is positioned over the light source. The reflector includes a flat portion and a shaped portion.
Implementation Method 3
along with virtual light sources created by empty openings coated with reflective materials
Data Source
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AI summary
A light source 60 such as a semiconductor light emitting diode 64 is positioned in a first opening 54 in a transparent member 50, which may function as a waveguide in a display. The transparent member surrounds the light source. No light source is positioned in a second opening 70 in the transparent member. In some embodiments, the first opening is shaped to direct light into the transparent member. In some embodiments, a reflector 66 is positioned over the light source. The reflector includes a flat portion and a shaped portion 68. The shaped portion extends from the flat portion toward the light source.