Unitary Lightguide With Angled Redirecting Features For Uniform Illumination
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Solution Overview
Problem
Current lightguide systems for surface lighting, such as display backlights and automotive tail lamps, require multiple light emitting diodes (LEDs) arranged along edges, leading to complex assembly and high costs, especially when using flexible lightguides, and often fail to provide spatially uniform lighting over a 2-dimensional area.
Innovation Solution
A unitary lightguide with a first and second section and a row of light redirecting features that includes a first portion directing light from one end to the other within the same section and a second portion directing light into the second section, along with light extractors to extract light via total internal reflection, allowing for spatially uniform lighting with fewer LEDs and enabling remote installation of light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple LEDs are arranged along edges of the lightguide, then illumination coverage is improved, but device complexity and assembly cost increase
Solution Approach 1:
The lightguide is divided into two functional sections: a first lightguide section for light propagation and a second lightguide section for light extraction. This segmentation allows a single LED to illuminate a larger area by directing light through the first section and extracting it along the second section, eliminating the need for multiple LEDs while maintaining comprehensive coverage.
Solution Approach 2:
The invention transitions from a one-dimensional edge illumination approach to a two-dimensional area illumination approach by creating a boundary region where light is redirected from the first section into the second section. This dimensional expansion allows light to be distributed across a larger surface area using fewer light sources.
2Illumination intensity
If multiple LEDs are used for surface lighting, then illumination intensity is improved, but manufacturing cost increases
Solution Approach 1:
The invention merges the functions of multiple LEDs into a single light source by combining light propagation and light extraction functions into one integrated lightguide structure. The first lightguide section transports light from a single LED, while the second lightguide section extracts and distributes this light across the illumination surface, achieving the illumination intensity of multiple LEDs with the cost of one.
Solution Approach 2:
The lightguide structure performs multiple functions: it propagates light from a single source, redirects light at the boundary region, and extracts light along the second section. This multi-functionality allows one LED to replace multiple LEDs while maintaining the required illumination intensity across the surface.
3Use of energy by moving object
If light sources are installed directly at lightguide edges, then light coupling efficiency is improved, but assembly complexity increases
Solution Approach 1:
The invention separates the light source from the lightguide structure, allowing the LED to be installed remotely at the first end of the first lightguide section rather than being directly coupled to multiple edge positions. This extraction of the light source from complex multi-point coupling arrangements simplifies assembly while maintaining efficient light coupling through the waveguide structure.
Solution Approach 2:
The first lightguide section acts as an intermediary that transports light from a remotely installed LED to the boundary region. This intermediary structure enables efficient light coupling from a single remote source and facilitates light redirection into the second section, simplifying the overall assembly process.
4Area of stationary object
If light is propagated through a long lightguide section, then light distribution area is improved, but light intensity uniformity deteriorates
Solution Approach 1:
The lightguide is segmented into two distinct sections with different functions: the first section propagates light over a long distance to expand the distribution area, while the second section extracts light to ensure uniform intensity across the illuminated surface. This segmentation resolves the trade-off between coverage area and intensity uniformity.
Solution Approach 2:
Different regions of the lightguide are assigned different optical properties: the first lightguide section is optimized for light propagation with minimal loss, while the second lightguide section is optimized for light extraction with appropriate extraction features. This local differentiation of optical quality ensures both large distribution area and uniform light intensity.
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 provides spatially uniform lighting over a 2-dimensional area using one or two light sources, reducing the complexity and cost of assembly by allowing light sources to be installed remotely from the lightguide, and improving light distribution through the use of light redirecting features and extractors.
Implementation Method 1
a second portion extending from proximate the first end of the first portion toward the second lightguide section between first and second ends of the second portion and making an angle with the first portion in a range from about 10 degrees to about 70 degrees
Implementation Method 2
a unitary lightguide with a first and second section and a row of light redirecting features that includes a first portion directing light from one end to the other within the same section and a second portion directing light into the second section
Implementation Method 3
The second lightguide section includes a plurality of light extractors for extracting light that would otherwise propagate within and along the second lightguide section
Data Source
AI summary
A unitary lightguide including a first lightguide section extending along a first direction and a second lightguide section extending along a second direction is described. The second lightguide section includes a plurality of light extractors for extracting light that would otherwise propagate within and along the second lightguide section. The unitary lightguide includes a boundary region disposed between and joining the first and second lightguide sections and including a plurality of spaced apart light redirecting features. Each light redirecting feature includes a first portion extending substantially parallel to the first direction, and a second portion extending from proximate the first end of the first portion toward the second lightguide section and making an angle with the first portion in a range from about 10 degrees to about 70 degrees.