Extruded Light Guide Panel With Diffusion Patterns

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Solution Overview

Problem

The miniaturization of display devices poses a challenge in forming thin light guide panels, as existing manufacturing methods like injection molding have limitations in achieving the required thickness and physical properties for efficient light guidance.

Innovation Solution

A light guide panel manufactured by extrusion with a unique configuration of diffusion patterns on its bottom surface, featuring recesses and protrusions, which allows for efficient light diffusion and guidance while maintaining a thicker profile at the light incidence surface to accommodate larger light source units, thereby minimizing light loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If injection molding is used to manufacture light guide panels, then manufacturing precision can be achieved, but the thickness cannot be reduced below a certain limit

Engineering Contradiction:
Improvethickness of light guide panelVSAvoidmanufacturability
Core Design Contradiction:
Length of moving objectVSEase of manufacture

Solution Approach 1:

The patent changes the manufacturing method from injection molding to extrusion process, which enables production of light guide panels with thickness of 0.1mm or less. The extrusion process parameters (temperature, pressure, die design) are optimized to achieve the required thickness while maintaining manufacturing feasibility and structural integrity.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If the thickness of light guide panel is reduced, then miniaturization of display devices is achieved, but light loss increases

Engineering Contradiction:
Improvethickness of light guide panelVSAvoidlight loss
Core Design Contradiction:
Length of moving objectVSLoss of energy

Solution Approach 1:

The patent introduces a reflective layer at the bottom surface of the light guide panel to locally enhance light reflection and redirection. This local quality enhancement compensates for the reduced light guidance efficiency caused by thinner panel thickness, thereby reducing overall light loss while maintaining miniaturization.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The light guide panel is constructed as a composite structure combining the transparent panel material with a reflective layer (such as metal foil or reflective coating). This composite design enables the thin panel to effectively guide light by combining transmission and reflection mechanisms, reducing light loss despite the reduced thickness.

Inventive Principle:
Principle #40Composite materials

3Strength

If injection molding is used, then complex patterns can be formed, but uniform residual stress and flexural strength cannot be achieved

Engineering Contradiction:
Improveflexural strengthVSAvoidmanufacturing process
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The extrusion process parameters (temperature profile, extrusion speed, die design) are optimized to ensure uniform cooling and stress distribution throughout the light guide panel. This results in uniform residual stress and enhanced flexural strength compared to injection molding, while maintaining the ability to form required patterns through the extrusion die and subsequent processing.

Inventive Principle:
Principle #35Parameter changes

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 extrusion method enables the production of light guide panels with specific physical properties such as uniform residual stress, lower melt mass flow rate, and flexural strength, allowing for effective light guidance and adaptation to smaller form factors in display devices.

Implementation Method 1

An edge-type backlight assembly needs a light guide panel for guiding light emitted by a light source toward a display panel. The light guide panel changes the path of light so as to guide the light toward the display panel.

Methodology Applied
Scientific EffectLight guidance: Waveguide (optics)

Implementation Method 2

The bottom surface includes a flat reference surface and a plurality of diffusion patterns

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP2853807B1Light guide panel, back light assembly and display apparatus each having the light guide panel
Publication Date: 2023.05.03 SAMSUNG DISPLAY CO LTD
  • EP2853807B1 patent drawingFigure 1~2
  • EP2853807B1 patent drawingFigure 3~4
  • EP2853807B1 patent drawingFigure 5~7

AI summary

A Light guide panel (100), back light assembly (1500) and display apparatus (2000) are provided. According to an aspect of the present invention, there is provided the light guide panel (100) which includes a top surface (104), a bottom surface (103), and four side surfaces, and one of the four side surfaces may be a light incidence surface (101).