Front Light Module Scratch Protection via Inverted Microstructures

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Solution Overview

Problem

Existing front light modules for displays, especially of the edge-lighting type, are prone to scratches on diffusion points or microstructures located at the top face of the light guide plate, which degrades display quality and renders the modules unusable.

Innovation Solution

A front light module design featuring a light guide plate with a first refractive index, a medium layer of a second refractive index, a transparent material layer for protection, and a transparent glue layer with pillar structures, where the refractive indices and structural patterns optimize light guidance and protection from scratches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If diffusion points or microstructures are located at the top face of the light guide plate to guide light downward, then light guidance efficiency is improved, but the surface becomes prone to scratches which degrades display quality

Engineering Contradiction:

Improvelight guidance efficiencyVSAvoidscratch resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent inverts the conventional design by moving the light-guiding microstructures from the top face to the bottom face of the light guide plate. This inversion allows the top face to remain smooth and scratch-resistant while the bottom face structures continue to perform the light guidance function effectively.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent transitions the light-guiding structures from a two-dimensional surface pattern on the top face to a three-dimensional structural arrangement on the bottom face, utilizing the vertical dimension and the interface between the light guide plate and the transparent glue layer to achieve light guidance.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If a protective layer is added over the light guide plate to prevent scratches, then scratch resistance is improved, but the structural complexity increases

Engineering Contradiction:

Improvescratch resistanceVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the light-guiding function from the top face surface and relocates it to the bottom face, thereby eliminating the need for a separate protective layer over the light-guiding structures. The top face becomes a simple protective surface without functional microstructures.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The top face of the light guide plate serves dual purposes: it acts as a protective surface against scratches and simultaneously functions as a light transmission surface without requiring additional protective layers, simplifying the overall structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the top face of the light guide plate is made smooth to prevent scratches, then scratch resistance is improved, but light guidance efficiency decreases

Engineering Contradiction:

Improvescratch resistanceVSAvoidlight guidance efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent inverts the location of light-guiding structures from the top face to the bottom face, allowing the top face to remain smooth for scratch resistance while the bottom face structures perform the light guidance function through refraction and total internal reflection at the interface with the transparent glue layer.

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 novel structure effectively protects the light guide plate from scratches and enhances the efficiency and uniformity of light guidance, improving display quality and extending the module's lifespan.

Implementation Method 1

the incident light beams of large angles of incidence can be kept from passing through the top face of the light guide plate by utilizing the total internal reflection at the interface between the light guide plate and the medium layer

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The transparent glue layer is placed under the light guide plate and has a third refractive index, wherein the third refractive index is larger than the refractive index of air and smaller than or equal to the first refractive index

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS8920018B2Front light module

Publication Date: 2014.12.30 E INK HLDG INC

AI summary

A front light module, including: a light source; a light guide plate, having a first refractive index and having a side face neighboring the light source; a medium layer, placed over the light guide plate and having a second refractive index, wherein the second refractive index is smaller than the first refractive index; a transparent material layer, placed over the medium layer; and a transparent glue layer, placed under the light guide plate and having a third refractive index, wherein the third refractive index is larger than the refractive index of air and smaller than or equal to the first refractive index.