Light-Guiding Plate Prism Layout for Uniform LCD Light Directivity

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Solution Overview

Problem

Existing liquid crystal display units face challenges in achieving uniform luminance distribution while varying light directivity, particularly in modes where the range of light-outgoing directions is narrowed or widened.

Innovation Solution

A light emitting device comprising a light-guiding plate with prisms of varying inclinations and densities, combined with a prism sheet and diffusing sheet, to control light directivity and enhance luminance uniformity by adjusting the range of light-outgoing directions based on the operation of multiple light sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the range of light-outgoing directions is narrowed to increase directivity, then light directivity is improved, but luminance uniformity deteriorates

Engineering Contradiction:
Improvelight directivityVSAvoidluminance uniformity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by varying the inclination angles and densities of prisms in different regions of the light-guiding plate. Specifically, the light-guiding plate includes a first region with prisms having first inclination angles and a second region with prisms having second inclination angles different from the first. This spatial variation in prism properties allows different regions to contribute differently to light distribution, achieving both high directivity in certain areas and overall luminance uniformity across the display surface.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the range of light-outgoing directions is widened to decrease directivity, then luminance distribution is improved, but light directivity deteriorates

Engineering Contradiction:
Improveluminance distributionVSAvoidlight directivity
Core Design Contradiction:
Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The patent implements local quality by creating distinct regions with different prism characteristics. The light-guiding plate comprises a first region with prisms having first inclination angles and a second region with prisms having second inclination angles. This regional differentiation enables the system to widen light distribution in some areas while maintaining directivity in others, achieving balanced luminance distribution without complete loss of directivity control.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies segmentation by dividing the light-guiding plate into multiple regions with different optical properties. The plate is segmented into a first region and a second region, each with prisms having different inclination angles. This segmentation allows independent optimization of light distribution characteristics in each region, enabling the overall system to achieve both widened light distribution and maintained directivity through the combined effect of different regions.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If prisms with uniform inclination are used, then manufacturing is simplified, but luminance uniformity across different viewing angles deteriorates

Engineering Contradiction:
Improveprism fabricationVSAvoidluminance uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by specifying different inclination angles forprisms in different regions. The light-guiding plate includes a first region withprisms having first inclination angles and a second region with prisms having second inclination angles. This approach requires more complex fabrication than uniformprisms, but the patent makes it manufacturable by using injection molding with specialized dies, thus achieving luminance uniformity while maintaining reasonable ease of manufacture.

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 effectively narrows or widens the range of light-outgoing directions, improving luminance uniformity and viewing angle characteristics, thereby enhancing display performance.

Implementation Method 1

a light-guiding plate (20), guides light going out from the plurality of light sources (10A, 10B), to the prism sheet (40)

Methodology Applied
Scientific EffectLight guidance: Reflection

Implementation Method 2

a prism sheet (40), controls light going out from the light-guiding plate (20)

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

a diffusing sheet (50), diffuses light going out from the prism sheet (40)

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3734141B1Display device
Publication Date: 2025.12.10 SONY GROUP CORP
  • EP3734141B1 patent drawingFigure 1
  • EP3734141B1 patent drawingFigure 2~3(C)
  • EP3734141B1 patent drawingFigure 4~5

AI summary

A display unit of the disclosure includes a light-emission section and a front display panel being disposed ona front side of the light-emission section, wherein the light-emission section comprises a light-guiding plate having a first main surface and a second main surface, a first end surface and a second end surface facing the first end surface for receiving light from a plurality of light sources, the first and second surfaces being perpendicular to the first and second main surfaces. The light-guiding plate includes a plurality of first slope sections and a plurality of second slope sections both provided on one of the main surfaces, in which the plurality of slope sections are provided to allow the light-guiding plate to be thinner, wherein an area of the second slop sections increases from the first end surface near the first light source toward a central region of the main surfaces and the height of the second sloped sections increases from the first end surface near the first light source toward the central region.