Light Guide Device with Embedded Sources and Masking Structures

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Solution Overview

Problem

Existing light guiding devices for backlighting applications face challenges in mechanical durability and optical performance due to the complexity of integrating light sources at the edge of transparent plastic components, leading to potential mechanical damage and dark spots in the illumination pattern.

Innovation Solution

A light guide device comprising a base substrate with mounted light sources, encapsulated by guide layers with varying refractive indices and reflective scattering structures, which directs light internally and masks the light sources, enhancing mechanical protection and optical coupling while minimizing dark spots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If light sources are distributed across the panel to minimize guiding length, then backlight thickness is reduced and efficiency is improved, but dark spots appear above the light sources

Engineering Contradiction:
Improvebacklight thicknessVSAvoiduniformity of light distribution
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The light guide plate is segmented into multiple regions with different scattering structures. First scattering structures are positioned above light sources to mask them, while second scattering structures are positioned in dark spot regions to redirect light and eliminate不均匀ities. This segmentation allows targeted optical control in different zones of the light guide plate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different scattering structures are applied to different locations of the light guide plate. The first scattering structures (e.g., white ink dots or prisms) are located directly above light sources to mask their appearance, while second scattering structures are located in dark spot regions to redirect light. This local differentiation of scattering properties enables simultaneous achievement of source masking and dark spot elimination.

Inventive Principle:
Principle #3Local quality

2Device complexity

If light sources are integrated by mechanical attachment at the edge of the transparent plastic component, then the device structure is simplified, but the production process complexity increases and mechanical damage susceptibility increases

Engineering Contradiction:
Improvestructural simplicityVSAvoidproduction process complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The light source integration process is merged with the light guide plate manufacturing process. The light guide plate is injection molded with embedded light source cavities and integrated scattering structures (white ink dots, prisms, or micro-lenses) formed during the same molding cycle. This combining of operations eliminates separate assembly steps and reduces production complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The scattering structures are preliminarily formed into the light guide plate during injection molding, before the light sources are installed. The cavities for light sources and the scattering structures are created in advance during the molding process, so that when light sources are later inserted, the optical control features are already in place. This preliminary formation of optical structures simplifies the overall manufacturing process.

Inventive Principle:
Principle #10Preliminary action

3Illumination intensity

If scattering structures or films are located within or on the surface of the transparent guide to achieve perpendicular light emission, then backlighting performance is improved, but the device thickness increases

Engineering Contradiction:
Improvebacklighting performanceVSAvoiddevice thickness
Core Design Contradiction:
Illumination intensityVSVolume of moving object

Solution Approach 1:

The scattering structures are implemented as thin surface features directly on the light guide plate rather than as separate thick components. White ink dots, surface prisms, or micro-lenses are formed as thin film or surface modifications during injection molding. These thin scattering structures achieve the required light redirection and masking functions while adding minimal thickness to the overall device.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The light guide plate performs multiple functions simultaneously: it guides light from edge-mounted sources, masks light sources through integrated scattering structures, eliminates dark spots through additional scattering structures, and provides structural support. By combining these functions into a single multi-functional component rather than separate elements, the overall device thickness is minimized while achieving all required optical performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 thin, efficient, and mechanically robust light guiding device with uniform light distribution, reduced power requirements, and a thinner structure, eliminating visible dark spots and simplifying the production process.

Implementation Method 1

light from the light source is guided through a transparent guide, typically made of plastic, by total internal reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

one or more scattering structures are located at the interface between the first and second guide layers and above the one or more sources of light

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2223012B1Light guides with embedded light sources, and method of manufacture
Publication Date: 2018.01.03 DESIGN LED PRODS
  • EP2223012B1 patent drawingFigure 1

AI summary

This invention relates to a light guide device and methods of manufacture. The light guide device is suitable for use in a range of applications, particularly in connection with the backlighting of displays, for example, liquid crystal displays. The light guide device comprises a combination of guide layers and one or more scattering structures in order to mask the appearance of one or more light sources.