Light Guide Panel Incidence Structure for Dark Portion Reduction

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Solution Overview

Problem

Conventional light guide panels in edge light type backlight units suffer from dark portions with low brightness due to insufficient light distribution, leading to irregular display quality and limited miniaturization of the backlight unit.

Innovation Solution

The introduction of dark portion reducing units with curved or flat surfaces, such as semi-conical or semi-pyramidal shapes, and diffusion units with saw-toothed patterns on the incidence surface to diffuse and redirect light, reducing dark areas and enhancing uniform brightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If light sources are installed at a lateral side of the light guide panel, then the backlight unit can be miniaturized, but dark portions with low brightness are created near the light sources

Engineering Contradiction:
Improvebacklight unit sizeVSAvoidbrightness uniformity
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The incidence surface of the light guide panel is segmented into multiple regions: a first region facing the light source, a second region opposite to the light source, and a third region connecting these two regions. This segmentation allows different optical functions to be applied to different areas, solving the brightness uniformity problem while maintaining compact size.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different surface treatments are applied to different regions of the light guide panel. The first region has a first surface treatment, the second region has a second surface treatment, and the third region has a third surface treatment. This local differentiation optimizes light distribution in each area, eliminating dark portions while preserving the edge-lit compact structure.

Inventive Principle:
Principle #3Local quality

2Device complexity

If light sources are installed at a lateral side of the light guide panel, then the backlight unit structure is simplified, but the usable screen area is reduced due to dark portions

Engineering Contradiction:
Improvebacklight unit structureVSAvoidusable screen area
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

By segmenting the light guide panel into distinct regions with different surface treatments, the design maintains the simple edge-lit structure while expanding the usable screen area. The third region acts as a transition zone that connects the light source area to the display area, ensuring uniform brightness across the entire screen.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The problem is solved by introducing a dimensional transition through the third region, which connects the first and second regions. This transitional zone allows light to be redistributed across the panel surface, expanding the effective display area without complicating the overall edge-lit structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If conventional surface treatments are applied to the light guide panel, then manufacturing is simple, but dark portions are created due to insufficient light distribution

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidlight distribution uniformity
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

Different surface treatments are applied to different regions of the light guide panel according to their specific optical requirements. The first region, second region, and third region each have tailored surface treatments that optimize light distribution locally, achieving uniform brightness while maintaining manufacturing feasibility through region-specific processing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The light guide panel is divided into multiple regions with different surface treatments, allowing manufacturers to apply treatments selectively to each region. This segmentation approach balances manufacturing simplicity with improved light distribution, as each region can be treated independently according to its optical function.

Inventive Principle:
Principle #1Segmentation

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 effectively minimizes dark portions, ensuring uniform brightness and increasing the usable screen area by symmetrically redirecting light from the light sources, thus improving display quality and enabling miniaturization of the backlight unit.

Implementation Method 1

the emitted light is converted into surface light by the LGP 20 and exit through an upper surface 17 of the LGP 20

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

Diffusion units that are disposed on the incidence surface facing the light sources and diffuse the incident light from the light sources

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

Diffusion units that are disposed on the incidence surface facing the light sources and diffuse the incident light from the light sources

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2293124B1Light guide panel and display device employing the same
Publication Date: 2015.04.08 SAMSUNG ELECTRONICS CO LTD
  • EP2293124B1 patent drawingFigure 1~2
  • EP2293124B1 patent drawingFigure 3~4
  • EP2293124B1 patent drawingFigure 5~6

AI summary

Provided are a light guide panel and a display device employing the same. The light guide panel includes: an incidence surface facing a plurality of light sources separated apart a predetermined distance; at least one dark portion reducing unit that is formed on the incidence surface between adjacent pairs of the slight sources and at both edges of the incidence surface, and reflects the light incident from the light sources to reduce the creation of dark portion units; an upper surface transmitting a portion of incident light and reflecting the rest of the incident light; and a lower surface facing the upper surface and reflecting the light incident from the incidence surfaces and dark portion reducing units. The light guide panel includes the dark portion reducing units to reduce the distance between the light source and the light source and thus reduce the size of a useless portion of a screen caused by dark portions.