Switchable Liquid Crystal Diffuser for Optical Component Reliability

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Solution Overview

Problem

Optical components in electronic devices, such as light diffusers, are prone to manufacturing defects like bubbles and broken seals, which can lead to undesirable tolerances and affect the performance of light manipulation systems.

Innovation Solution

The electronic device incorporates a switchable diffuser with liquid crystal material between substrates, surrounded by a sealant and spacer walls, which allows for both flood illumination and structured light modes, and includes conductive material to prevent electrical shorts by coupling electrodes to metal pads, while using additional spacer structures to control sealant spread and maintain a predictable cell volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a light diffuser is used to diffuse light emitted from a light source, then light manipulation capability is improved, but manufacturing defects such as bubbles and broken seals occur

Engineering Contradiction:

Improvelight manipulation capabilityVSAvoidmanufacturing defect-free operation

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Spacer walls are introduced as intermediary structures between the sealant and liquid crystal layer. These spacer walls prevent direct contact and potential defects between the sealant and liquid crystal material, eliminating bubbles and broken seals while maintaining the light diffusing function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The diffuser structure is segmented into distinct functional layers: substrates, liquid crystal layer, sealant, and spacer walls. This segmentation allows each component to be optimized independently and assembled precisely, preventing manufacturing defects while maintaining optical performance.

Inventive Principle:

Principle #1Segmentation

2Reliability

If additional spacer walls are added to prevent electrical shorts, then electrical isolation is improved, but device complexity increases

Engineering Contradiction:

Improveelectrical isolationVSAvoidnumber of spacer walls

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The spacer walls serve multiple functions simultaneously: they maintain the cell volume, prevent electrical shorts between electrodes, and provide structural support for the sealant. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If conductive material is added to the sealant to couple electrodes to metal pads, then electrical connection is improved, but risk of electrical shorts increases

Engineering Contradiction:

Improveelectrical connectionVSAvoidelectrical short risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Spacer walls act as electrical insulators between the conductive sealant material and the electrodes. This intermediary structure allows the sealant to provide electrical connection to metal pads while preventing direct electrical contact between electrodes, thereby eliminating the risk of electrical shorts.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration enhances the reliability and versatility of optical components by preventing manufacturing defects and ensuring accurate light manipulation, enabling both diffused and structured light modes with improved electrical isolation and assembly precision.

Implementation Method 1

The diffuser may include liquid crystal material between first and second substrates

Methodology Applied

Scientific EffectLiquid crystal effect: Liquid Crystals

Implementation Method 2

Conductive material in the sealant may be used to couple a top electrode to a metal pad on a bottom substrate

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS11105677B2Electronic devices with switchable diffusers

Publication Date: 2021.08.31 APPLE INC

AI summary

An electronic device may be provided with a display. An optical component window may be formed in the inactive area of the display. The optical component window may transmit infrared light from an infrared light source. The infrared light source may include a diffuser to allow the light source to operate in a flood illumination mode and a structured light mode. The diffuser may include liquid crystal material between first and second substrates. A sealant may surround the liquid crystal layer, and one or more spacer walls may be located between the sealant and the liquid crystal layer. An additional spacer wall may be used outside of the sealant to prevent metal from creating an electrical short between electrodes in the diffuser. Conductive material in the sealant may be used to couple a top electrode to a metal pad on a bottom substrate.