Side-Lighting Plastic Optical Fiber with Translucent Cladding

Solution Overview

Problem

Existing plastic optical fibers for side lighting suffer from uneven light emission, low mechanical strength, and poor handling due to large outer diameters and high elasticity, making them unsuitable for decorative and sensor applications.

Innovation Solution

A two-layer plastic optical fiber with a core and cladding made of specific clear resins, where the cladding is polymerized with 90% or more vinylidene fluoride for optimal crystallinity and refractive index, and a numerical aperture of 0.45 to 0.65, ensuring even light emission and improved mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a light diffusion layer is formed outside the core and cladding to enable side lighting, then light can be emitted from the side surface, but the outer diameter increases and elasticity increases, resulting in poor bend nature and difficult handling

Engineering Contradiction:

Core Design Contradiction:

Illumination intensityVSEase of operation

Solution Approach 1:

The invention extracts the light diffusion function from a separate external layer and integrates it into the cladding layer itself. By making the cladding layer translucent or transparent rather than opaque, the fiber enables side lighting without requiring an additional diffusion layer, thereby maintaining a compact structure with good bend nature and handling characteristics.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the cladding layer's structural function with its light diffusion function. The cladding layer simultaneously provides mechanical support and enables light emission from the side surface through its translucent/transparent property, eliminating the need for a separate diffusion layer and resolving the contradiction between side lighting capability and ease of handling.

Inventive Principle:

Principle #5Merging (Combining)

2Illumination intensity

If the cladding is made translucent or transparent to enable light emission, then side lighting is achieved, but mechanical strength may be reduced

Engineering Contradiction:

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The invention changes the optical parameter of the cladding layer from opaque to translucent or transparent, enabling light emission. This parameter change is achieved through material selection or processing while maintaining the cladding's mechanical strength by optimizing its thickness and material composition, thus resolving the contradiction between light emission capability and mechanical strength.

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If a noncircular cross-sectional form is used for the core to create a lighting section, then side lighting is enabled, but lighting is weak and uneven, and regions may not light depending on viewing direction

Engineering Contradiction:

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The invention avoids asymmetric core cross-sections that cause directional lighting issues. Instead, it uses a symmetric circular core combined with a translucent/transparent cladding layer, which provides uniform light emission in all directions around the fiber, eliminating viewing-angle dependency and achieving consistent lighting uniformity.

Inventive Principle:

Principle #4Asymmetry

4Illumination intensity

If the cladding is removed to form an exposure region, then side lighting is enabled, but mechanical strength is reduced and lighting is uneven

Engineering Contradiction:

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

Instead of removing the cladding to enable side lighting (which weakens the fiber), the invention inverts the approach by making the cladding itself translucent or transparent. This allows the cladding to remain intact, maintaining mechanical strength while simultaneously enabling light emission from the side surface through its modified optical properties.

Inventive Principle:

Principle #13The other way round (Inversion)

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 a plastic optical fiber with even light emission along its length, enhanced mechanical strength, and improved flexibility, making it suitable for decorative, industrial, and sensor applications.

Implementation Method 1

the cladding layer has a translucent or transparent property, light passes through the cladding layer from a side surface of the optical fiber

Methodology Applied

Scientific EffectLight transmission: Refraction

Implementation Method 2

light radiated from one of the ends of the fiber repeatedly undergoes total reflection at a phase boundary between the core and the cladding to be efficiently transmitted to the other end

Methodology Applied

Scientific EffectTotal reflection: Total Internal Reflection

Data Source

PatentEP3064970B1Illumination plastic optical fiber and method of manufacturing same

Publication Date: 2019.12.04

AI summary

There are provided an optical fiber as a linear radiator uniform in the longer direction thereof, and a lighting device using the optical fiber. The optical fiber is a lighting fiber having a core and a cladding. In the fiber, as the cladding, there is used a polymer obtained by polymerizing a polymerizing ingredient containing 90% or more by weight of vinylidene fluoride, and the cladding has a crystallinity of 45% to 52%.