Polarizer Trimming for Liquid Crystal Displays

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Solution Overview

Problem

Electronic devices with liquid crystal displays face challenges in ensuring the polarizer size matches the glass display layer, leading to unsightly edges or reduced visible area due to the use of bezels to cover overhanging polarizer edges.

Innovation Solution

A protective elastomeric polymer coating is applied to the peripheral edge of the glass color filter layer substrate to prevent damage during polarizer trimming, allowing for precise trimming of the polarizer to match the glass layer dimensions without damaging the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the polarizer is made larger to cover the glass display layer, then the visible display area increases, but the polarizer edge overhangs and creates unsightly visible edges

Engineering Contradiction:

Improvevisible display areaVSAvoidpolarizer edge alignment

Core Design Contradiction:

Area of stationary objectVSShape

Solution Approach 1:

The patent applies preliminary trimming action to the polarizer before final assembly, using a trimming tool to remove excess polarizer material that would otherwise overhang the glass display layer. This preliminary action prevents the unsightly overhang problem while maintaining full visible display area.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical trimming methods with laser trimming technology. The laser beam precisely ablates the polarizer material along the desired boundary, providing superior edge accuracy and eliminating mechanical contact that could damage the fragile polarizer or glass layers.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If the polarizer is trimmed precisely to match the glass layer, then the display aesthetics improve, but the glass substrate is vulnerable to damage during trimming operations

Engineering Contradiction:

Improvepolarizer size matchingVSAvoidglass substrate integrity

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent introduces a protective coating layer applied beforehand to the glass substrate periphery. This coating acts as a cushioning layer that absorbs mechanical stresses during trimming operations, preventing direct contact between trimming tools and the fragile glass edges, thus protecting substrate integrity while enabling precise trimming.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The protective coating serves as an intermediary layer between the glass substrate and the trimming tool. It mediates the interaction by providing a sacrificial surface that can be trimmed without damaging the underlying glass, allowing precise polarizer trimming while protecting the substrate.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Shape

If a bezel is used to cover the polarizer edge, then the unsightly edge is hidden, but the visible display area is reduced

Engineering Contradiction:

Improvedisplay edge appearanceVSAvoidvisible display area

Core Design Contradiction:

ShapeVSArea of stationary object

Solution Approach 1:

The patent extracts and removes the problematic polarizer overhang through precise trimming, eliminating the need for a bezel covering. By taking out the excess polarizer material that causes aesthetic issues, the solution achieves clean edges without sacrificing visible display area to a bezel structure.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potentially harmful situation of polarizer overhang into a benefit by using laser trimming to create a perfectly aligned edge. The excess polarizer material, which would normally require covering with a bezel, is instead precisely removed to create a clean, aesthetic edge that enhances display appearance without reducing visible area.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 coating protects the glass substrate during polarizer trimming, enabling accurate sizing of the polarizer to match the glass layer, thus enhancing the aesthetic appeal and visibility of the display by eliminating unsightly edges and reducing the need for bezels.

Implementation Method 1

a coating is deposited on a peripheral edge of the glass color filter layer substrate. The coating is formed from an elastomeric polymer such as silicone

Methodology Applied

Scientific EffectCoating deposition: Deposition (physical)

Data Source

PatentUS8988636B2Methods for trimming polarizers in displays

Publication Date: 2015.03.24 APPLE INC

AI summary

An electronic device is provided with a display such as a liquid crystal display mounted in an electronic device housing. The display has a layer of liquid crystal material sandwiched between an upper display layer such as a color filter layer and a lower display layer such as a thin-film-transistor layer. An upper polarizer is formed on the upper surface of the color filter layer. A lower polarizer is formed on the lower surface of the thin-film-transistor layer. To protect display layers such as a glass color filter layer substrate for the color filter layer from damage during polarizer trimming operations, a coating is deposited on a peripheral edge of the glass color filter layer substrate. The coating may be formed from an elastomeric polymer such as silicone and may remain in place or may be removed following trimming operations.