Reflective Display Panel Shielding for Spacer-Induced Light Leakage

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Solution Overview

Problem

In reflective display panels, spacers disrupt the alignment of the alignment layer, leading to dark state light leakage and reduced display contrast due to the height difference between the spacer and the film surface.

Innovation Solution

The implementation of light shielding patterns that overlap with the second side edge of the spacers but not the first, ensuring effective alignment coverage while minimizing reflectivity reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If spacers are disposed between the first substrate and the second substrate to maintain uniform liquid crystal layer thickness, then the liquid crystal layer thickness uniformity is improved, but dark state light leakage occurs due to disrupted alignment layer alignment

Engineering Contradiction:
Improveliquid crystal layer thickness uniformityVSAvoiddark state light leakage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The light shielding structure is divided into multiple segments: a first light shielding portion overlapping the first side edge of the spacer, a second light shielding portion overlapping the second side edge, and a third light shielding portion overlapping the projection of the spacer. This segmentation allows targeted shielding of light leakage paths while preserving alignment layer functionality in other regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the light shielding structure have different functions: the first and second light shielding portions address light leakage at spacer edges, while the third light shielding portion addresses light leakage from the spacer projection. This local differentiation optimizes the shielding effect where needed while minimizing impact on overall display performance.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If light shielding patterns are disposed to cover spacers to reduce light leakage, then dark state light leakage is reduced, but reflectivity of the reflective display panel is reduced

Engineering Contradiction:
Improvedark state light leakageVSAvoiddisplay reflectivity
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The light shielding structure is segmented into three distinct portions with different positions and functions. By dividing the shielding function across multiple segments rather than using a single continuous shield, the patent achieves effective light leakage blocking while minimizing the total area occupied by light shielding materials, thereby preserving reflectivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light shielding structure applies partial shielding only where light leakage occurs (at spacer edges and projection) rather than complete shielding across the entire display area. This partial action approach is sufficient to eliminate light leakage while maintaining reflectivity in the remaining display regions.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4600724A1Refelctive display panel
Publication Date: 2025.08.13 HANNSTAR DISPLAY CORP
  • EP4600724A1 patent drawingFigure 1
  • EP4600724A1 patent drawingFigure 2
  • EP4600724A1 patent drawingFigure 3

AI summary

A reflective display panel (10, 11, 12, 20) includes a first substrate (101), a second substrate (102), pixel structures (PX, PX1, PX2, PX3), spacers (SP, SP-A), a first alignment layer (AL1), a second alignment layer (AL2), a liquid crystal layer (LCL), and light shielding patterns (LSP, LSP-A). The pixel structures (PX, PX1, PX2, PX3) are disposed on the first substrate (101). The spacers (SP, SP-A) and the liquid crystal layer (LCL) are disposed between the first and second substrates (101, 102). The first alignment layer (AL1) is disposed on the first substrate (101) and has a first alignment direction (AD1). The second alignment layer (AL2) is disposed on the second substrate (102) and has a second alignment direction (AD2). Each spacer (SP, SPA) has a first side edge (SPe1) and a second side edge (SPe2) facing away from each other and sequentially arranged along the first or second alignment direction (AD1, AD2). In a stacking direction of the first and second substrates (101, 102), each light shielding pattern (LSP, LSP-A) overlaps with the second side edge (SPe2) of one of the spacers (SP, SP-A), but does not overlap with the first side edge (SPe1) thereof.