Reflective Display Panel Optics for Yellow Tint Correction

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Solution Overview

Problem

Reflective display panels with circular polarizers often exhibit a yellowish background color due to their inherent properties, which affects display performance.

Innovation Solution

A reflective display panel design incorporating a liquid crystal layer with a maximum phase retardation between 85 nm and 115 nm and a polarizer with a hue b* between 0 and 3.5, optionally with a quarter-wave plate, to adjust the optical properties and eliminate the yellowish tint, while maintaining or improving display contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a circular polarizer is used in the reflective display panel, then the display can achieve low power consumption and reflective characteristics, but the background color becomes yellowish which affects display quality

Engineering Contradiction:

Improvepower consumptionVSAvoidbackground color quality

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling the maximum phase retardation of the liquid crystal layer (85-115 nm) and the hue b* value of the polarizer (0-3.5) to compensate for the yellowish tint. By adjusting these optical parameters, the display achieves a whiter background color while maintaining the reflective characteristics and low power consumption of circular polarizer-based displays.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining the liquid crystal layer with specific polarizer materials having controlled hue characteristics. This composite structure allows the display to maintain the reflective properties of circular polarizers while introducing materials that compensate for the yellowish coloration, achieving a balanced optical performance.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the maximum phase retardation of the liquid crystal layer is increased, then the display contrast may be improved, but the background color may shift away from white

Engineering Contradiction:

Improvedisplay contrastVSAvoidbackground color accuracy

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent demonstrates parameter changes by establishing an optimal range for maximum phase retardation (85-115 nm) rather than maximizing it indefinitely. Within this controlled range, the display achieves sufficient contrast while preventing excessive color shift. The patent further refines this by correlating phase retardation values with required polarizer hue b* values, showing that higher phase retardation requires lower hue b* to maintain white background.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If the hue b* of the polarizer is reduced, then the yellowish tint is reduced, but the display contrast may deteriorate

Engineering Contradiction:

Improvebackground color whitenessVSAvoiddisplay contrast

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by establishing an inverse relationship between polarizer hue b* and maximum phase retardation. By controlling the phase retardation within 85-115 nm, the patent creates a buffer that allows for polarizer hue b* values from 0-3.5 while maintaining both white background and adequate contrast. This parameter coupling strategy shows that lower hue b* values can be compensated by optimized phase retardation parameters.

Inventive Principle:

Principle #35Parameter changes

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 design effectively corrects the yellowish background color to a whiter appearance and enhances display contrast by optimizing the phase retardation and hue parameters of the liquid crystal layer and polarizer.

Implementation Method 1

A maximum phase retardation of the liquid crystal layer is greater than or equal to 85 nm and less than or equal to 115 nm

Methodology Applied

Scientific EffectPhase retardation: Birefringence

Implementation Method 2

A single hue b* of the polarizer is greater than or equal to 0 and less than or equal to 3.5

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 3

the reflective display panel further includes a quarter-wave plate disposed between the polarizer and the liquid crystal layer

Methodology Applied

Scientific EffectPhase shift: Birefringence

Implementation Method 4

The pixel driving layer is disposed on the first substrate and is provided with a reflective layer

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS20250370294A1Reflective display panel

Publication Date: 2025.12.04 HANNSTAR DISPLAY CORP

AI summary

A reflective display panel including a first substrate, a second substrate, a liquid crystal layer, a pixel driving layer and a polarizer is provided. The first substrate and the second substrate are arranged to be overlapped with each other. The liquid crystal layer is disposed between the first substrate and the second substrate. The pixel driving layer is disposed on the first substrate and is provided with a reflective layer. The polarizer is disposed on a side of the liquid crystal layer facing away from the reflective layer and overlaps the liquid crystal layer. A maximum phase retardation of the liquid crystal layer is greater than or equal to 85 nm and less than or equal to 115 nm. A single hue b* of the polarizer is greater than or equal to 0 and less than or equal to 3.5.