Multiview Backlight Optical Mask Mitigating Moiré

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Solution Overview

Problem

Passive displays, such as LCDs and EP displays, lack the ability to emit light, limiting their practical applications due to their inherent low power consumption and limited use in emitting light.

Innovation Solution

A multiview backlight system is introduced, comprising an array of multibeam unit cells with a multibeam element and an optical mask element, where the optical mask element has a first portion aligned with the multibeam element and a laterally displaced second portion, configured to scatter light into directional beams for different views, and an array of light valves to modulate these beams, enabling both multiview and 2D display modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If optical mask elements are used in multiview backlight to create directional light beams, then multiview display functionality is improved, but visibility of the optical mask elements becomes problematic especially in 2D mode

Engineering Contradiction:
Improvemultiview display functionalityVSAvoidvisibility of optical mask elements
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The optical mask element is divided into multiple segments corresponding to different view directions. Each segment directs light to a specific viewing angle, allowing the mask to be optimized for multiview functionality while reducing its overall visibility impact through distributed segmentation across the display surface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optical mask element employs different optical properties in different regions. Areas corresponding to multiview functionality have higher optical density for directional control, while areas visible in 2D mode have reduced optical density or are positioned to minimize visibility, creating local quality variations that address both requirements.

Inventive Principle:
Principle #3Local quality

2Use of energy by moving object

If passive displays are used to achieve low power consumption, then energy efficiency is improved, but the ability to emit light is lost

Engineering Contradiction:
Improvepower consumptionVSAvoidlight emission capability
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

A backlight unit is introduced as an intermediary light source behind the passive display panel. This backlight provides the necessary illumination for the passive display to function, enabling both low-power operation when the backlight is off and sufficient brightness when activated, thus mediating between power consumption and light emission requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 multiview backlight system effectively provides directional light beams for multiview displays, enhancing their functionality and reducing visibility of the optical mask elements, especially in 2D mode, while maintaining low power consumption.

Implementation Method 1

each multibeam unit cell has a multibeam element configured to scatter out of the light guide a portion of the guided light as a plurality of directional light beams having different directions

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

an overall size of the optical mask element is configured to reduce or eliminate Moiré associated with the optical mask element

Methodology Applied
Scientific EffectMoiré effect: Moiré Effect

Data Source

PatentEP3874199B1Multiview backlight, display, and method having optical mask elements
Publication Date: 2024.10.23 LEIA INC
  • EP3874199B1 patent drawingFigure 1A~1B
  • EP3874199B1 patent drawingFigure 2~3A
  • EP3874199B1 patent drawingFigure 3B~3C

AI summary

A multi view backlight and multi view display employ an optical mask element having a first portion and a laterally displaced second portion to mitigate Moiré associated with the optical mask element. The multiview backlight includes an array of multibeam unit cells distributed across a light guide. Each multibeam unit cell has a multibeam element configured to scatter out a portion of guided light as a plurality of directional light beams having different directions corresponding to different views of the multiview display. Each multibeam unit cell further includes an optical mask element having the first portion aligned and co-extensive with the multibeam element and the second portion laterally displaced within the multibeam unit cell from the first portion. One or both of the lateral displacement and an overall size of the optical mask element is configured to mitigate Moiré associated with the optical mask element.