Anisotropic Light Diffusion Member for High Contrast Displays

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Solution Overview

Problem

Existing light diffusion sheets for liquid crystal display devices suffer from reduced contrast and display quality due to light reflection at high incident angles, particularly when polarized light interacts with V-shaped grooves, leading to inefficient light diffusion.

Innovation Solution

A light diffusion member with a polarizing plate is designed, featuring a rectangular substrate with light shielding layers and anisotropic light diffusion portions that have a larger incident surface area than the emitting surface, ensuring anisotropic diffusion of light in the azimuth direction, and a polarizing plate with a transmission axis orthogonal to the diffusion member's strong diffusion direction, enhancing contrast and display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a light diffusion sheet with V-shaped grooves is used to broaden the viewing angle, then the diffusion angle of light is improved, but light reflection at high incident angles reduces contrast and display quality

Engineering Contradiction:

Improveviewing angleVSAvoidlight reflection

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces symmetric V-shaped grooves with asymmetric light diffusion portions having a light incident end surface with a larger area than the light emitting end surface. This asymmetric geometry allows light entering from the larger incident surface to be diffused preferentially in the azimuth direction while minimizing reflection at high incident angles, thus maintaining both wide viewing angle and high contrast

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent introduces light shielding layers at specific locations (regions other than where light diffusion portions are formed) to selectively control light paths. These localized shielding structures prevent harmful reflections in specific areas while preserving the diffusion function in other areas, thereby improving contrast without sacrificing viewing angle

Inventive Principle:

Principle #3Local quality

2Loss of energy

If light diffusion portions with larger incident surface area are used to reduce light loss, then luminance is improved, but device complexity increases

Engineering Contradiction:

Improvelight lossVSAvoidstructure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the light diffusion portions: the asymmetric geometry simultaneously achieves light diffusion, reflection control, and luminance enhancement. By integrating these functions into a single structural element rather than using separate components, the patent reduces overall device complexity while maintaining the benefits of reduced light loss and improved luminance

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The light diffusion portions serve multiple purposes: they diffuse light in the azimuth direction to broaden viewing angle, their asymmetric geometry minimizes reflection at high incident angles to improve contrast, and their larger incident surface area reduces light loss to enhance luminance. This multi-functionality eliminates the need for separate components for each function, thereby reducing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 improves contrast and display quality by anisotropically diffusing light in the azimuth direction, reducing light loss, and maintaining high luminance, while preventing moiré interference with pixel arrays, thus providing a wider viewing angle and better visibility.

Implementation Method 1

Part of light perpendicularly entering the light diffusion layer exhibits total reflection at the wall faces of the grooves

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

Light which enters from the light incident end surface is anisotropically diffused in an azimuth direction seen from a normal direction of the substrate

Methodology Applied

Scientific EffectAnisotropic diffusion: Anisotropy

Implementation Method 3

a polarizing plate with a transmission axis orthogonal to the diffusion member's strong diffusion direction, enhancing contrast and display quality

Methodology Applied

Scientific EffectPolarization filtering: Polarisation

Data Source

PatentUS9594194B2Light diffusion member, light diffusion member with polarizing plate, and method for fabrication of light diffusion member with polarizing plate

Publication Date: 2017.03.14 SHARP KK

AI summary

A light diffusion member includes a substrate having light transmissivity, a plurality of light shielding layers, and light diffusion portions. The light diffusion portions have a light-emitting end surface, a light incident end surface which has a larger area than the area of the light-emitting end surface, and a reflecting face. Light which enters from the light incident end surface is anisotropically diffused in an azimuth direction seen from a normal direction of the substrate, and the height from the light incident end surface to the light-emitting end surface of the light diffusion portion is greater than the thickness of the light shielding layers. A hollow portion of the light diffusion portion is formed in the formation region of the light shielding layers, and air is present in the hollow portion.