Light Guide Member V-Grooves for Uniform Luminance

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Solution Overview

Problem

Conventional light guide members in backlight units fail to provide uniformly distributed light, leading to non-uniform luminance and image quality issues in display devices, and the addition of optical sheets to address this problem increases cost, weight, and size.

Innovation Solution

A light guide member with V-shaped or triangular-shaped grooves and projections is employed, which concentrates light and reduces spreading, ensuring uniform luminance distribution by adjusting exit angles and pitch, and incorporating dot-like patterns near the light source to eliminate bright lines or areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional light guide members are used, then the structure is simple, but the luminance distribution is non-uniform with bright lines and dark areas

Engineering Contradiction:
Improveluminance distribution uniformityVSAvoidlight guide member structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light guide member incorporates V-shaped or triangular-shaped grooves at specific locations (portions not overlapping with light sources) to locally modify light diffusion characteristics. This local structural modification creates additional light extraction points that compensate for dark areas and reduce bright lines, achieving uniform luminance distribution without complicating the overall device structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The light guide member is divided into multiple portions with different structures: portions overlapping with light sources maintain a flat upper surface for efficient light coupling, while portions not overlapping with light sources incorporate V-shaped or triangular grooves for enhanced light diffusion. This segmentation allows each portion to perform its specific function optimally, resolving the luminance uniformity issue

Inventive Principle:
Principle #1Segmentation

2Illumination intensity

If additional optical sheets are added to improve luminance uniformity, then the luminance distribution improves, but the cost, weight, and size increase

Engineering Contradiction:
Improveluminance distribution uniformityVSAvoidbacklight unit weight
Core Design Contradiction:
Illumination intensityVSWeight of moving object

Solution Approach 1:

The light guide member integrates multiple functions into a single component: light guiding, light diffusion, and luminance uniformity control. The V-shaped or triangular grooves are directly formed on the light guide member itself, eliminating the need for separate optical sheets and reducing the overall weight of the backlight unit

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light guide member serves multiple purposes: it guides light from the light source, diffuses light to cover the display area, and the V-shaped or triangular grooves provide additional light extraction functionality. This multi-functionality replaces what would traditionally require multiple separate optical components, reducing weight and cost

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

3Illumination intensity

If additional optical sheets are added to improve luminance uniformity, then the luminance distribution improves, but the size increases

Engineering Contradiction:
Improveluminance distribution uniformityVSAvoidbacklight unit volume
Core Design Contradiction:
Illumination intensityVSVolume of moving object

Solution Approach 1:

The light guide member integrates multiple functions into a single component: light guiding, light diffusion, and luminance uniformity control. The V-shaped or triangular grooves are directly formed on the light guide member itself, eliminating the need for separate optical sheets and reducing the overall volume of the backlight unit

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of adding optical sheets in the vertical dimension (increasing thickness), the invention modifies the light guide member in the horizontal dimension by incorporating V-shaped or triangular grooves on its upper surface. This approach achieves luminance uniformity without increasing the backlight unit's overall size

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

4Illumination intensity

If light is guided at larger radiation angles, then more light reaches distant portions, but the light intensity decreases and diffusion is weak

Engineering Contradiction:
Improvelight intensityVSAvoidlight guide member length
Core Design Contradiction:
Illumination intensityVSLength of moving object

Solution Approach 1:

V-shaped or triangular grooves are strategically placed on portions of the light guide member that are not overlapping with light sources. These grooves create localized light extraction points that compensate for the natural attenuation of light intensity over distance, ensuring uniform luminance distribution along the entire length of the light guide member

Inventive Principle:
Principle #3Local quality

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 achieves improved uniformity in light distribution, reducing the bright line/area effect and enhancing image quality without the need for additional optical sheets, thus reducing cost and size while maintaining performance.

Implementation Method 1

A light guide member with V-shaped or triangular-shaped grooves and projections is employed, which concentrates light and reduces spreading, ensuring uniform luminance distribution by adjusting exit angles and pitch

Methodology Applied
Scientific EffectLight concentration and refraction: Refraction

Implementation Method 2

incorporating dot-like patterns near the light source to eliminate bright lines or areas

Methodology Applied
Scientific EffectLight scattering and diffusion: Scattering

Data Source

PatentEP1906218B1Light guide member and blacklight unit including light guide member
Publication Date: 2018.05.30 SAMSUNG DISPLAY CO LTD
  • EP1906218B1 patent drawingFigure 1A~1C
  • EP1906218B1 patent drawingFigure 2A~2C
  • EP1906218B1 patent drawingFigure 3A~3C

AI summary

A light guide member (100) for guiding light may include a first pattern on a first side (101) of the light guide member (100), the first pattern may include a plurality of first features (110) extending along a first direction, and a plurality of second features (120) extending along a second direction, wherein the first direction crosses the second direction, the first feature (110) has a first feature size, the second feature (120) has a second feature size, and the first feature size may be less than the second feature size.