Optical Filter Photo-Orientation for 3D Displays

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Solution Overview

Problem

Current methods for manufacturing optical filters for 3D image display devices are complex, costly, and have low productivity, particularly due to chemical etching and difficulties in controlling chiral characteristics during light exposure.

Innovation Solution

A method involving the formation of a polymer layer on a substrate, followed by a single continuous photo-orientation process using a patterned mask and polarizer to create an alignment layer with different orientation directions, and subsequent formation of a retardation layer, simplifying the manufacturing process and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If chemical etching is used to manufacture optical filters, then manufacturing precision can be achieved, but device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improveoptical filter precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces chemical etching processes with a photo-orientation method that uses light exposure and polymer alignment to create the optical filter pattern. This substitution eliminates complex chemical handling, etching control, and waste management systems while achieving comparable manufacturing precision through photopolymerization and alignment layer formation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the manufacturing approach from chemical parameter control (etching depth, chemical concentration) to optical parameter control (light intensity, exposure time, polarization angle). This allows precise control of optical filter properties through well-established photopolymerization kinetics and alignment physics, simplifying the overall manufacturing process.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If chemical etching and temperature control methods are used, then optical filter functionality can be achieved, but productivity decreases due to complex processes

Engineering Contradiction:
Improveoptical filter functionalityVSAvoidmanufacturing productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines multiple separate manufacturing steps (alignment layer formation, pattern creation, optical axis orientation) into a single integrated photo-orientation process. By using a patterned mask with specific polarization characteristics, the method simultaneously defines the optical filter pattern and orients the polymer alignment layers, eliminating sequential chemical etching and temperature control steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary alignment of the polymer layer using a uniform alignment layer before applying the patterned mask. This preliminary action ensures that the photo-orientation step directly creates the final optical filter pattern without requiring subsequent chemical processing or temperature control steps to achieve the desired optical characteristics.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If chiral characteristics are controlled during light exposure, then optical filter performance can be optimized, but manufacturing stability decreases due to temperature sensitivity

Engineering Contradiction:
Improvechiral characteristics controlVSAvoidmanufacturing stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces temperature control mechanisms with optical control mechanisms. Instead of using temperature-sensitive chiral liquid crystal alignment, the method uses polarized light exposure to directly orient the polymer alignment layers. This substitution eliminates temperature sensitivity while maintaining precise control over the optical filter's chiral characteristics through polarization angle and exposure intensity control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enhances productivity and process efficiency by simplifying the manufacturing process and achieving effective polarization control for 3D image display devices, allowing for improved 3D image projection without the need for complex chemical etching or unstable temperature control.

Implementation Method 1

the polarizer has two distinguishable regions, each of which transmit differently polarized light to each other

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

photo-orientating the polymer layer by positioning a patterned mask above the polymer layer, positioning a polarizer above the patterned mask, and irradiating ultraviolet light onto the polymer layer from the upper side of the polarizer

Methodology Applied
Scientific EffectPhoto-orientation: Photopolymerisation

Data Source

PatentEP2372433B1Method for manufacturing an optical filter for a stereoscopic image display device
Publication Date: 2018.04.11 LG CHEM LTD
  • EP2372433B1 patent drawingFigure 1
  • EP2372433B1 patent drawingFigure 2
  • EP2372433B1 patent drawingFigure 3

AI summary

The present invention relates to a method for manufacturing an optical filter for a stereoscopic image display device, which forms an alignment layer having different orientating directions along a fine region via a one-time continuous photo orientation process. The method comprising: forming a polymer layer on a substrate; a photo-orienting step comprising positioning a patterned mask above the polymer layer, the patterned mask having alternating light transmission regions and light shield regions arranged in both horizontal and a vertical directions to selectively transmit different polarized light, positioning a polarizer above the patterned mask where the polarizer has two distinguishable regions that transmit different polarized light, and downwardly irradiating UV light onto the polymer layer from above the polarizer, thereby forming an alignment layer having different orientating directions according to fine regions of the polymer layer; and forming a retardation layer on the alignment layer. The alignment layer in which the fine regions with different orientating directions are formed alternately and continuously is obtained via a one-time continuous photo-orientation process. Therefore, the photo-orientation process and the method for manufacturing the optical filter are simplified in comparison with the conventional art. As a result, the process yield and productivity in the manufacturing of an optical filter for a 3D image display device are improved.