Discrete Light Guide Planar Illumination Uniformity
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Solution Overview
Problem
Existing systems for creating a planar, uniformly emitting illumination surface using light guides face challenges such as non-uniform light distribution at borders, limited scalability, and miniaturization constraints due to the need for multiple side-emitting light sources and complex optical structures.
Innovation Solution
The use of integrated monolithic light guides with spatially distinct in-coupling, concentration, and out-coupling regions, where the light source is embedded and can be positioned adjacent to the in-coupling region, allowing for uniform light emission across a continuous surface by overlapping and tilable light-guide elements with polished or refracted sidewalls and index-matching materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple side-emitting light sources are used to illuminate a large surface area, then the illumination coverage is improved, but the device complexity and miniaturization are worsened
Solution Approach 1:
The light guide is divided into multiple discrete segments or tiles, each containing its own light source. These segments are arranged in a grid pattern to form a large-area illumination surface. Each segment independently generates and distributes light, eliminating the need for a single complex optical system while achieving scalable area coverage.
Solution Approach 2:
The patent transitions from edge-illuminated light guides to surface-illuminated discrete light guide elements. Light sources are positioned on the top surface of each element rather than at the edges, allowing for more flexible arrangements and reducing the complexity of light coupling structures while maintaining large area coverage.
2Area of stationary object
If light guides are assembled from multiple elements to increase surface area, then the illumination coverage is improved, but the uniformity of light distribution at borders is worsened
Solution Approach 1:
The patent applies different optical properties to different regions of the light guide elements. The center regions use standard light-distributing materials, while the border regions incorporate light-absorbing materials or structures that prevent light leakage and non-uniformity. This localized modification ensures uniform light distribution across the entire assembled surface, including at the borders between elements.
3Illumination intensity
If complex optical structures are used to distribute light evenly, then the illumination uniformity is improved, but the miniaturization and ease of manufacture are worsened
Solution Approach 1:
The patent combines multiple functions into the discrete light guide elements themselves. Each element integrates light generation (via embedded LEDs), light distribution (via internal optical structures), and border light management (via light-absorbing materials) into a single manufacturable component. This integration simplifies the overall manufacturing process while maintaining uniform light distribution across large assembled surfaces.
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 approach enables the creation of large, uniformly illuminated surfaces with minimal non-uniformity, efficient light retention, and reduced stray light, facilitating scalable and miniaturized planar illumination systems with improved brightness and color uniformity.
Implementation Method 1
a light guide that receives point-source light on an edge of the guide and distributes the light uniformly over a surface of the guide
Implementation Method 2
the sidewalls of the light-guide elements may be polished, curved, or set at a 90-degree angle to either reflect or refract light as desired
Implementation Method 3
the sidewalls of the light-guide elements may be polished, curved, or set at a 90-degree angle to either reflect or refract light as desired
Implementation Method 4
An index-matching material may be deposited between adjacent light-guide elements and/or on the light-emitting surfaces of light-guide elements
Data Source
AI summary
In one aspect, a planar illumination area includes two light-guide elements, each with an out-coupling region. At least a portion of each out-coupling region overlaps with at least a portion of the other. The overlapping region emits a substantially uniform light output power.