Evaporation Shadow Mask Layout for Accurate OLED Offset Measurement

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Solution Overview

Problem

Existing methods for measuring the offset of evaporation shadow masks in OLED display panels are complex and costly, requiring multiple fine metal masks and resulting in high project costs.

Innovation Solution

A packaged evaporation shadow mask and display panel design that uses a single mask with offset marks arranged in a specific pattern, allowing for accurate offset measurement with reduced complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple evaporation shadow masks are used for offset detection, then measurement accuracy is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveoffset measurement accuracyVSAvoidnumber of evaporation shadow masks

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple offset detection functions into a single evaporation shadow mask by providing multiple offset mark openings (first offset mark opening and second offset mark opening) within the same mask structure. This allows simultaneous formation of multiple offset marks (first offset mark and second offset mark) during the evaporation process, eliminating the need for multiple separate masks while maintaining comprehensive offset detection capability across different regions of the display panel.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If multiple evaporation shadow masks are used for offset detection, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improveoffset measurement accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges multiple offset detection functions into a single evaporation shadow mask by providing multiple offset mark openings (first offset mark opening and second offset mark opening) within the same mask structure. This allows simultaneous formation of multiple offset marks (first offset mark and second offset mark) during the evaporation process, eliminating the need for multiple separate masks while maintaining comprehensive offset detection capability across different regions of the display panel.

Inventive Principle:

Principle #5Merging (Combining)

3Difficulty of detecting and measuring

If offset mark openings are positioned at edge areas of main evaporation areas, then offset detection capability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveoffset detection capabilityVSAvoidmask structure complexity

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent segments the offset detection function by providing distinct offset mark openings (first offset mark opening and second offset mark opening) at different locations on the evaporation shadow mask. The first offset mark opening is positioned at the edge area of the first main evaporation area, while the second offset mark opening is positioned at the edge area of the second main evaporation area. This segmentation allows independent detection of offsets for different evaporation regions, improving overall detection capability while maintaining clear structural organization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The evaporation shadow mask is designed with multi-functionality by incorporating both main evaporation areas for forming light-emitting layers and compensation layers, as well as offset mark openings for detection purposes. This universal design allows the single mask to perform both production functions (evaporating functional layers) and measurement functions (forming offset marks for alignment verification) simultaneously, reducing the need for separate detection masks.

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 enables accurate measurement of evaporation offsets while reducing the number of masks needed and lowering the measurement cost, thereby simplifying the process and decreasing expenses.

Implementation Method 1

the light-emitting layer and the compensation layer in the same OLED device have exactly the same shape and are respectively prepared by using two different evaporation shadow masks

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS12239004B2Display panel, packaged evaporation shadow mask, display device and preparation method

Publication Date: 2025.02.25 WUHAN TIANMA MICRO ELECTRONICS CO LTD

AI summary

A display panel includes a display area and a non-display area; the display area includes multiple first sub-pixel minimum repeating units; the multiple first sub-pixel minimum repeating units are sequentially and periodically arranged in a first direction, and in the first direction, a center distance between any two adjacent ones of the multiple first sub-pixel minimum repeating units is d1; the non-display area includes a first offset mark A1 and a second offset mark A2 arranged in the first direction; a center distance L1 between the first offset mark A1 and the second offset mark A2 is an integral multiple of the center distance d1 between the first sub-pixel minimum repeating units.