Deposition Mask Structure for Shadow-Free OLED Patterning

Solution Overview

Problem

Conventional deposition masks used in organic light emitting display device manufacturing result in external and internal shadows due to the adjacency of pattern and body portions, leading to increased bezel size and potential damage to circuit components from excessive pressure.

Innovation Solution

A deposition mask design featuring a body portion, pattern portions that penetrate the body, blocking portions that contact the substrate to prevent deposition material from reaching unwanted areas, and support portions to reduce pressure, with the blocking portions and body portions having tapered sidewalls to enhance material distribution and prevent shadows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional deposition mask with adjacent pattern portion and body portion is used, then the deposition process can be performed, but external shadows form and the bezel size increases

Engineering Contradiction:

Improvedeposition precisionVSAvoidbezel size

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The mask is divided into distinct functional portions: the body portion for structural support, the pattern portion for material deposition, the blocking portion for preventing external shadows, and the support portion for substrate contact. This segmentation allows each portion to perform its specific function optimally, preventing the formation of external shadows while maintaining deposition precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The blocking portion acts as an intermediary element between the pattern portion and the substrate, specifically designed to block deposition material from reaching areas outside the pattern portion, thereby preventing external shadow formation without affecting the deposition process within the pattern area.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the pattern portion and body portion are adjacent, then the mask structure is simple, but internal shadows form due to material spraying outside the pattern portion

Engineering Contradiction:

Improvemask structureVSAvoiddeposition uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The mask is divided into distinct functional portions: the body portion for structural support, the pattern portion for material deposition, the blocking portion for preventing external shadows, and the support portion for substrate contact. This segmentation allows each portion to perform its specific function optimally, preventing the formation of external shadows while maintaining deposition precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the mask have different local properties: the blocking portion has high material blocking capability with tapered sidewalls to prevent shadowing, while the support portion has optimized geometry for uniform substrate contact. This local differentiation ensures that each area of the mask performs its specific function with high precision.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If the blocking portion contacts the substrate directly, then external shadows are prevented, but excessive pressure may damage circuit components

Engineering Contradiction:

Improveshadow preventionVSAvoidpressure damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The mask is divided into distinct functional portions: the body portion for structural support, the pattern portion for material deposition, the blocking portion for preventing external shadows, and the support portion for substrate contact. This segmentation allows each portion to perform its specific function optimally, preventing the formation of external shadows while maintaining deposition precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The support portion acts as an intermediary between the mask and the substrate, distributing the contact pressure over a larger area and preventing excessive localized pressure that could damage circuit components, while still maintaining the substrate in the correct position for deposition.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of manufacture

If the blocking portion has vertical sidewalls, then the structure is simple to manufacture, but internal shadows form due to material accumulation

Engineering Contradiction:

Improveblocking portion fabricationVSAvoiddeposition uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The blocking portion features tapered sidewalls rather than vertical sidewalls. This curved geometry allows deposition material to flow more uniformly along the sidewalls, preventing material accumulation and internal shadow formation. The tapered shape guides the material flow in a controlled manner, ensuring uniform deposition while remaining manufacturable.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 effectively prevents external shadows, reduces bezel size, and disperses pressure, thereby improving yield and component integrity by ensuring precise material deposition and minimizing internal shadows.

Implementation Method 1

a deposition mask in which a deposition material is deposited on a substrate

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

a shadow may form on the substrate in an area in which the pattern portion and the body portion are adjacent to each other

Methodology Applied

Scientific EffectShadow effect: Shadow

Data Source

PatentUS12252773B2Deposition mask and deposition apparatus including the same

Publication Date: 2025.03.18 SAMSUNG DISPLAY CO LTD

AI summary

A deposition mask includes a body portion, a pattern portion that penetrates the body portion and is configured to allow deposition material to pass through the body portion, a blocking portion disposed on the body portion, and a support portion disposed on the body portion adjacent to the blocking portion. The blocking portion contacts a display substrate, blocks the deposition material, and defines the pattern portion. The support portion contacts the display substrate.