Sub-pixel Compression for Moire Reduction in Multi-Display Systems

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Solution Overview

Problem

Multi-display systems experience moire interference due to interactions between color filters in stacked display layers, leading to reduced image quality and clarity, as existing solutions using diffusers result in blurry images and are difficult to implement in reduced form factors.

Innovation Solution

Sub-pixel compression techniques are employed to remap red and blue sub-pixels onto green sub-pixels, forming a white stripe that reduces color filter interactions, combined with refractive beam mappers to expand this stripe, effectively eliminating moire interference without sacrificing resolution or contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If diffusive optics are used to blur the rear display layer, then moire interference is reduced, but image clarity and resolution are sacrificed

Engineering Contradiction:
Improvemoire interferenceVSAvoidimage clarity
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

A refractive beam mapper is introduced as an intermediary optical element between the rear display layer and the viewer. This beam mapper uses refraction to selectively redirect light from different sub-pixels (red, green, blue) to corresponding positions on the front display layer, thereby eliminating moire interference without blurring the image. The refractive element acts as a mediator that transforms the color-filtered light paths into alignment with the front display's pixel structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/diffusive approach (using diffusers to blur images) with an optical refraction-based system. Instead of mechanically scattering light to reduce moire patterns, the invention uses refractive optics to precisely redirect light rays, achieving moire reduction while preserving image sharpness and clarity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If specialized diffuser patterns are used, then moire interference is reduced, but manufacturing difficulty increases

Engineering Contradiction:
Improvemoire interferenceVSAvoiddiffuser pattern fabrication
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention replaces complex specialized diffuser patterns with a refractive beam mapper that uses standard optical refraction principles. The beam mapper can be manufactured using conventional lens fabrication techniques rather than requiring specialized diffuser pattern manufacturing, significantly easing the manufacturing process while achieving the same moire reduction effect.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If diffusing elements are placed between polarizers and substrates, then moire interference is reduced, but system complexity and manufacturing constraints increase

Engineering Contradiction:
Improvemoire interferenceVSAvoidsystem structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The refractive beam mapper is positioned as an intermediary element in the display stack, between the rear display layer and the front display layer. This placement allows it to function independently of the polarizer and substrate structures, simplifying the overall system architecture. The beam mapper can be integrated into the existing display stack without requiring modifications to the polarizer or substrate layers, reducing manufacturing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If sub-pixel compression is used to remap colored sub-pixels, then moire interference is eliminated, but device complexity increases

Engineering Contradiction:
Improvemoire interferenceVSAvoidoptical element structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The refractive beam mapper merges the functions of multiple optical operations into a single integrated element. It simultaneously performs color separation, beam redirection, and spatial mapping of sub-pixels to their corresponding positions on the front display layer. This consolidation of functions into one refractive element achieves moire elimination without requiring multiple separate optical components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 significantly reduces or eliminates moire interference in multi-layer display systems, maintaining high resolution and contrast while preventing the introduction of detrimental side-effects on image quality.

Implementation Method 1

refractive beam mappers to expand this stripe

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

sub-pixel compression techniques are employed to remap red and blue sub-pixels onto green sub-pixels

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP3365723B1Method and system for performing sub-pixel compression in order to reduce moirÉ interference in a display system including multiple displays
Publication Date: 2021.12.22 APTIV TECHNOLOGIES LTD
  • EP3365723B1 patent drawingFigure 1~3
  • EP3365723B1 patent drawingFigure 4~5
  • EP3365723B1 patent drawingFigure 6

AI summary

A multi-display system (e.g., a display including multiple display panels) includes at least first and second displays (e.g., display panels or display layers) arranged substantially parallel to each other in order to display three-dimensional (3D) features to a viewer(s). At least sub-pixel compression is utilized in order to reduce moiré interference.