Flexible Lightguide With Stacked Fiber Input
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Solution Overview
Problem
Existing lightguides, such as optical fibers and edge-lit films, face inefficiencies in light coupling and transmission due to absorption, scattering, and rigidity, making it difficult and costly to achieve uniform illumination, especially with flexible films and plates.
Innovation Solution
A flexible translucent sheet with overlapping edges and discrete legs that are folded to create a stacked light input area, coated with reflective or lower refractive index materials, enhances internal reflection and light distribution, allowing efficient light coupling and emission, even with thin sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flexible plastic films with small thickness are used, then flexibility and ease of manufacture are improved, but light-coupling efficiency deteriorates
Solution Approach 1:
The patent transitions from coupling light to the edge of a thin film (2D edge coupling) to coupling light to the end face of an optical fiber (3D volumetric coupling). By using an optical fiber with a diameter comparable to the light source dimensions, the patent creates a volumetric coupling interface that dramatically improves light-coupling efficiency while maintaining flexibility through the use of flexible optical fiber materials.
Solution Approach 2:
The patent introduces an optical fiber as an intermediary component between the light source and the flexible film. The optical fiber acts as a mediator that efficiently receives light from the light source and transmits it to illuminate the film, decoupling the light-coupling efficiency requirement from the film thickness and flexibility requirements.
2Loss of energy
If rigid plates with thickness greater than 2 mm are used, then light-coupling efficiency is improved, but flexibility and ease of assembly deteriorate
Solution Approach 1:
The patent employs flexible optical fiber materials and thin flexible films to create a lightweight, flexible illumination system. The optical fiber itself is made flexible through material selection, and the illuminated film is kept thin for flexibility, while light-coupling efficiency is maintained through the volumetric end-face coupling geometry rather than relying on plate thickness.
Solution Approach 2:
The patent moves away from the conventional approach of using thick rigid plates for light coupling and instead uses an optical fiber with dimensions in a different regime (comparable to light source size). This dimensional change enables flexible, thin-film applications while maintaining efficient light coupling through the fiber's end face.
3Illumination intensity
If optical fibers are precisely aligned with the film edge, then light distribution uniformity is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The patent allows the flexible film to serve multiple functions: it acts as both the light distribution medium and the structural support for positioning the optical fiber. By integrating the film's mechanical properties into the alignment system, the patent eliminates the need for separate complex alignment mechanisms, allowing the film itself to guide and maintain the fiber's position during assembly.
Solution Approach 2:
The patent utilizes the flexibility and elasticity of the film to dynamically accommodate and maintain optical fiber alignment. The film's mechanical compliance allows for self-adjustment during assembly, compensating for tolerances and maintaining uniform light distribution without requiring rigid, precision-machined alignment structures.
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 significantly improves light-coupling efficiency and reduces costs by allowing flexible sheets to efficiently transmit light over longer distances with uniform illumination, maintaining flexibility and ease of assembly, suitable for various applications including signage and displays.
Implementation Method 1
The received light is transmitted through the sheet via internal reflection such that the unfolded portion/body 104 is internally illuminated
Implementation Method 2
A flexible translucent sheet with overlapping edges and discrete legs that are folded to create a stacked light input area, coated with reflective or lower refractive index materials, enhances internal reflection and light distribution
Data Source
AI summary
A flexible translucent sheet is folded to have portions of its bounding edge closely situated in overlapping relationship, and these overlapping portions are illuminated by a light source. The illumination is transmitted through the interior of the sheet to any adjacent unfolded area of the sheet, which may bear emission areas which are treated so that the light emits from the sheet at these areas. Preferred versions of the invention have a series of legs cut into one edge of the sheet, and the legs are then bundled in stacked relationship, with a light source providing light input into the bundle.