Dual-Mode TIR Light Guide for Uniform Lighting
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Solution Overview
Problem
Conventional lighting systems with optical waveguides face inefficiencies in light coupling, leading to 10-30% light loss and non-uniform brightness due to hotspotting, which requires bezels to mask these issues, limiting light output and color uniformity.
Innovation Solution
A lighting subassembly utilizing an optical element that functions as both an outcoupling Total Internal Reflection (TIR) light guide and a direct throughput lens, with a light scattering composition and lenticular surface for efficient light distribution, reducing hotspotting and increasing the light emitting area, and optionally using a cover lens for further uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional optical waveguides are used for edge lighting, then thin form factor and adjustable lighting output are achieved, but 10-30% light is lost due to inefficient optical coupling
Solution Approach 1:
The optical element is divided into two functional zones: a first region that guides light via total internal reflection and a second region that directly transmits light. This segmentation allows different portions of light to take different paths, improving overall coupling efficiency while maintaining the thin form factor of the waveguide structure.
Solution Approach 2:
The optical element serves multiple functions simultaneously: it acts as both a light guide for TIR and a direct transmission path for uncoupled light. This multi-functionality eliminates the need for separate components to handle different light paths, reducing light loss while maintaining the compact design.
2Productivity
If full edge coupling is targeted, then light guide efficiency is improved, but uncoupled light is wasted and hotspots occur near the light source
Solution Approach 1:
The optical element is divided into two functional zones: a first region that guides light via total internal reflection and a second region that directly transmits light. This segmentation allows different portions of light to take different paths, improving overall coupling efficiency while maintaining the thin form factor of the waveguide structure.
Solution Approach 2:
The patent converts the harmful effect of uncoupled light (which would normally be wasted) into a beneficial direct transmission path. The second region of the optical element is specifically designed to capture and transmit uncoupled light directly to the output, turning what was previously a loss into a useful contribution to the overall light output.
3Illumination intensity
If bezels are added to mask hotspots, then non-uniform brightness is hidden, but light emitting area percentage is reduced
Solution Approach 1:
The optical element is divided into two functional zones: a first region that guides light via total internal reflection and a second region that directly transmits light. This segmentation allows different portions of light to take different paths, improving overall coupling efficiency while maintaining the thin form factor of the waveguide structure.
Solution Approach 2:
The patent extracts the light transmission function from the traditional waveguide-only approach and adds a direct transmission path. By taking out the uncoupled light and providing it with a dedicated transmission path, the system eliminates hotspots without requiring bezels to mask them, thereby preserving maximum light emitting area.
4Speed
If light is coupled into optical light guide, then light propagation is achieved, but color variation over angle is accentuated
Solution Approach 1:
The optical element is divided into two functional zones: a first region that guides light via total internal reflection and a second region that directly transmits light. This segmentation allows different portions of light to take different paths, improving overall coupling efficiency while maintaining the thin form factor of the waveguide structure.
Solution Approach 2:
The patent applies different optical properties to different regions of the optical element. The first region is optimized for TIR with specific refractive index properties, while the second region is optimized for direct transmission. This local differentiation of optical properties ensures that each region performs its specific function optimally, maintaining color uniformity while enabling light propagation.
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 enhances light output and uniformity by increasing direct transmission and reducing hotspotting, achieving a higher percentage of light emission and improved luminous efficacy, with a significant reduction in bezel area, resulting in a more efficient and aesthetically appealing lighting fixture.
Implementation Method 1
an optical element that functions as both an outcoupling Total Internal Reflection (TIR) light guide
Implementation Method 2
with a light scattering composition and lenticular surface for efficient light distribution
Implementation Method 3
Means for outcoupling light are provided by lenticular surface 9 on the optical element opposing face 6
Data Source
AI summary
A lighting subassembly and components are provided which increase light output and uniformity of brightness and color by use of an optical element that functions simultaneously as an outcoupling TIR light guide and a direct throughput lens. It provides typical benefits of an edgelit light guide design including shallow depth, extended emitting area, and off axis light distributions such as batwing distributions particularly useful in downlighting and other lighting applications. Additionally, area dedicated to bezels or edge reflectors can be greatly reduced or eliminated due to decreased hotspotting to provide a fixture face with very high percentage of light emitting area.