Photoalignment Mask with Transflective Regions for LCD

Solution Overview

Problem

Conventional photoalignment methods for liquid crystal displays require multiple masks and repetitive UV irradiation processes, leading to potential misalignment and reduced transmittance due to the complexity of forming various liquid crystal alignment directions.

Innovation Solution

A photoalignment method that reduces the number of masks needed by using a mask with light blocking, transmissive, and transflective regions, allowing for different light irradiation energies and angles to achieve multiple alignment directions with improved precision and reduced misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple masks are used for UV irradiation to form various liquid crystal alignment directions, then the alignment precision is improved, but the device complexity and risk of misalignment increase

Engineering Contradiction:

Improveliquid crystal alignment precisionVSAvoidmask usage complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The alignment layer is divided into multiple irradiation regions (first irradiation region, second irradiation region, third irradiation region) with different light irradiation amounts, allowing different alignment directions to be formed in different regions simultaneously through a single mask structure with light blocking, transmissive, and transflective regions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A single mask structure performs multiple functions by incorporating light blocking regions, transmissive regions, and transflective regions that work together to create various alignment directions in different irradiation regions during one UV irradiation process, eliminating the need for multiple separate masks

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If multiple masks are used for UV irradiation to form various liquid crystal alignment directions, then the alignment precision is improved, but the risk of misalignment and transmittance reduction increase

Engineering Contradiction:

Improveliquid crystal alignment precisionVSAvoidalignment reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The alignment layer is divided into multiple irradiation regions (first irradiation region, second irradiation region, third irradiation region) with different light irradiation amounts, allowing different alignment directions to be formed in different regions simultaneously through a single mask structure with light blocking, transmissive, and transflective regions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A single mask structure performs multiple functions by incorporating light blocking regions, transmissive regions, and transflective regions that work together to create various alignment directions in different irradiation regions during one UV irradiation process, eliminating the need for multiple separate masks

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Manufacturing precision

If repetitive UV irradiation processes are performed to achieve various alignment directions, then the alignment precision is improved, but the processing time increases

Engineering Contradiction:

Improveliquid crystal alignment precisionVSAvoidprocessing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The alignment layer is divided into multiple irradiation regions (first irradiation region, second irradiation region, third irradiation region) with different light irradiation amounts, allowing different alignment directions to be formed in different regions simultaneously through a single mask structure with light blocking, transmissive, and transflective regions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple UV irradiation processes that would normally be performed separately are merged into a single irradiation process by using a composite mask structure with light blocking, transmissive, and transflective regions that create different alignment directions in different regions simultaneously

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

This method enhances the alignment of liquid crystal molecules, improves transmittance, and simplifies the manufacturing process by minimizing the need for multiple masks and reducing processing time, while maintaining high visibility and response speed.

Implementation Method 1

A conventional method enabling the liquid crystals to have the pre-tilt angle includes a contact-type rubbing method of applying physical pressure to an alignment layer thereof by using a roller, and a photoalignment method for forming the pre-tilt angle by irradiating ultraviolet ("UV") light to the alignment layer.

Methodology Applied

Scientific EffectPhotoalignment: Photo-oxidation

Implementation Method 2

The mask may include a light blocking unit to partially shield a part of the first alignment layer

Methodology Applied

Scientific EffectLight blocking: Absorption (EM radiation)

Implementation Method 3

a light transmittance of the transflective region may be greater than that of the light blocking region and smaller than that of the transmissive region

Methodology Applied

Scientific EffectLight transmittance: Light

Data Source

PatentUS8767154B2Photoalignment method and liquid crystal display

Publication Date: 2014.07.01 SAMSUNG DISPLAY CO LTD

AI summary

A photoalignment method includes irradiating light in a first direction to a first alignment layer, and irradiating light in a second direction opposite the first direction, after disposing a first mask on the first alignment layer.