Variable Transmittance Optical Element for Sunroof Heat Blocking

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Solution Overview

Problem

Current optical elements for sunroofs lack the ability to dynamically control transmittance in response to external signals and fail to effectively block infrared heat, leading to inefficient energy usage.

Innovation Solution

An optical element comprising a polarizing layer, a liquid crystal layer with anisotropic dye, and a composite layer with a first oxide layer, a metal layer, and a second oxide layer, where the alignment of the liquid crystal compound and dye can be altered by an external signal, allowing for variable transmittance and enhanced infrared blocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional optical element is used for sunroof, then the structure is simple and cost is low, but the transmittance cannot be dynamically controlled and infrared heat blocking is ineffective

Engineering Contradiction:
Improvedynamic transmittance controlVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the optical element's transmittance variable through the liquid crystal layer. The liquid crystal molecules can change their alignment state in response to external signals (voltage, temperature, light), thereby dynamically adjusting the transmittance of the optical element between different states (e.g., transparent to opaque), enabling adaptive control rather than fixed transmittance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs composite materials by combining multiple functional layers: a polarizing layer for light polarization, a liquid crystal layer for dynamic optical control, and a composite layer with specific oxide and metal components for infrared heat blocking. This multi-layer composite structure integrates different material properties to achieve both dynamic transmittance control and thermal management functions simultaneously.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If the optical element blocks infrared heat effectively, then energy saving is improved, but the visible light transmittance may be reduced

Engineering Contradiction:
Improveheat blocking efficiencyVSAvoidvisible light transmittance
Core Design Contradiction:
Loss of energyVSIllumination intensity

Solution Approach 1:

The patent applies local quality by designing the composite layer with specific oxide and metal components that selectively interact with different wavelengths of electromagnetic radiation. The layer structure is optimized to block infrared wavelengths (heat) while maintaining high transmittance in the visible wavelength range, thereby achieving localized spectral selectivity where different regions of the spectrum are treated differently.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by adjusting the composition, thickness, and optical properties of the composite layer components (oxide layers and metal layer) to achieve the desired balance between infrared blocking and visible light transmittance. By modifying parameters such as layer thickness, material composition, and refractive index, the optical element can be tuned to block heat while preserving visibility.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the liquid crystal alignment is changed by external signal, then the transmittance control is improved, but the energy consumption increases

Engineering Contradiction:
Improvetransmittance control capabilityVSAvoidenergy consumption for signal application
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by using intermittent or pulsed signaling to control the liquid crystal layer rather than continuous energy application. The liquid crystal layer can maintain its aligned state after a brief voltage pulse, allowing the system to switch between transmittance states with periodic or on-demand signaling, thereby reducing overall energy consumption compared to continuous power application.

Inventive Principle:
Principle #19Periodic action

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 optical element achieves dynamic control of transmittance and efficient heat blocking, reducing energy consumption by switching between transmission and blocking modes based on applied signals, suitable for various optical devices like sunroofs.

Implementation Method 1

the liquid crystal layer may be formed on the polarizing layer, and include a liquid crystal compound and an anisotropic dye... the alignment of the liquid crystal compound may be changed by a signal applied by the composite layer

Methodology Applied
Scientific EffectLiquid crystal alignment: Liquid Crystals

Implementation Method 2

The liquid crystal layer may be a guest-host type liquid crystal layer... exhibits an anisotropic light absorbing effect by that the dichroic dye is arranged along the arrangement of the liquid crystal compound

Methodology Applied
Scientific EffectAnisotropic light absorption: Dichroic Filter

Implementation Method 3

the composite layer has a low transmittance with respect to light in an infrared region... the composite layer has a low transmittance in an infrared region... heat may be blocked

Methodology Applied
Scientific EffectInfrared absorption: Absorption (EM radiation)

Data Source

PatentEP3115832B1Optical element
Publication Date: 2019.02.20 LG CHEM LTD
  • EP3115832B1 patent drawingFigure 1~2
  • EP3115832B1 patent drawingFigure 3~4
  • EP3115832B1 patent drawingFigure 5~6

AI summary

The present application relates to an optical element. The exemplary optical element may have a variable transmittance by whether an external signal is applied or not. Also, since the optical element may apply the external signal by using a composite layer having a low transmittance to light in an infrared region, the optical element may block heat, and save energy. Such an optical element may be usefully employed in various optical devices, for example, a sunroof.