Angled-Edge Guide Elements for Thin, Uniform Lightguides
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Solution Overview
Problem
Existing light emitting devices, such as displays and backlights, face challenges in achieving a very thin form factor with specific angular light output profiles while maintaining high light uniformity and flexibility, as conventional edge-lit configurations with rigid lightguides result in thick frames and limited design configurations.
Innovation Solution
A film-based lightguide with coupling lightguides folded at different angles and stacked on the back side of a reflective spatial light modulator, where the coupling lightguides are folded along linear fold lines with varying angles and tapered lateral edges to direct light efficiently into a thin lightguide, enhancing light extraction and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid lightguides with thick frames are used in edge-lit configurations, then structural strength and light guidance are improved, but device thickness and volume increase
Solution Approach 1:
The patent replaces rigid lightguides with flexible thin-film lightguides that can be folded and bent. The thin-film structure maintains sufficient mechanical strength through material selection and structural design while reducing device thickness to less than 1mm, eliminating the need for thick rigid frames
Solution Approach 2:
The patent implements a stacked configuration where multiple lightguide layers are nested together, with each layer containing coupling lightguides folded at different angles. This nesting approach consolidates multiple light guidance functions into a compact vertical arrangement, reducing overall device volume while maintaining structural integrity
2Length of stationary object
If lightguide thickness is reduced to achieve thin form factor, then device volume is reduced, but light coupling efficiency and uniformity deteriorate
Solution Approach 1:
The patent divides the light coupling function into multiple discrete coupling lightguides distributed across the lightguide surface. Each coupling lightguide is folded at specific angles (e.g., 45°, 90°, 135°) to independently direct light from the edge toward the center, ensuring uniform light distribution across the thin lightguide thickness
Solution Approach 2:
The patent transitions from traditional edge-only light coupling to multi-dimensional light coupling by folding coupling lightguides at various angles in three-dimensional space. This angular diversity in the folded configuration enables effective light injection into the thin lightguide from multiple directions, maintaining coupling efficiency despite reduced thickness
3Stability of the object's composition
If conventional rigid frames are used, then structural stability is improved, but design flexibility and adaptability are reduced
Solution Approach 1:
The patent replaces static rigid frames with dynamic flexible thin-film structures that can be folded and configured in multiple arrangements. The flexible lightguides can be bent to different angles and stacked in various configurations, enabling adaptable design for different device form factors while maintaining structural stability through careful material and structural design
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 achieves a thin form factor with improved light uniformity and flexibility, allowing for more design configurations and efficient light coupling into a thinner lightguide, reducing thickness and overall volume while maintaining high light flux and uniformity.
Implementation Method 1
a plurality of light extraction features arranged within the light emitting region, the plurality of light extraction features frustrate totally internally reflected light from the light source propagating in the lightguide region
Implementation Method 2
the linear fold lines of the plurality of coupling lightguides are oriented at different fold angles such that a difference between fold angles of adjacent coupling lightguides of the plurality of coupling lightguides is greater than 5 degrees
Implementation Method 3
the plurality of light extraction features frustrate totally internally reflected light from the light source propagating in the lightguide region such that light exits the lightguide in the light emitting region
Data Source
AI summary
A guide element for guiding folds of coupling lightguides of a film-based lightguide has a plurality of angled edges oriented at different angles to each other in a plane orthogonal to a thickness direction of the guide element. The angled edges may have a curvature in a plane comprising the thickness direction of the guide element. A device may include the guide element and a lightguide formed from a film having opposing surfaces with a thickness not greater than 0.5 millimeters therebetween and a plurality of coupling lightguides in a form of strips of the film extending from and continuous with a lightguide region of the film, each coupling lightguide of the plurality of coupling lightguides terminates in a bounding edge between two lateral edges of the coupling lightguide. Each coupling lightguide may be folded over an angled edge of the guide element.