Liquid Crystal Electronic Mirror With Refractive Index Gradient Backup

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional vehicle mirrors suffer from issues such as excessive glare, limited field of view, damage susceptibility, and aerodynamic drag, while electronic mirrors, although enhancing safety and convenience, may fail due to camera or display malfunctions, necessitating a backup mechanism.

Innovation Solution

An electronic mirror incorporating a liquid crystal cell with a varying voltage profile across its electrodes to generate a refractive index gradient, providing magnification and reflective functionality even when the display fails, using a liquid crystal layer with controlled orientation and refractive index variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid crystal cell with varying voltage profile is used to provide magnification and reflective functionality, then the mirror maintains functionality without electronic components, but the device complexity increases due to the need for precise voltage control across different regions

Engineering Contradiction:
Improvemirror functionalityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a non-uniform voltage distribution across the liquid crystal layer, with different voltage values applied to different regions (higher voltage at edges, lower at center). This spatial variation in voltage produces the desired magnification effect and maintains reflective functionality without requiring complex electronic backup systems.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by varying the voltage parameter across different regions of the liquid crystal cell. By changing the voltage from the center to the edges of the liquid crystal layer, the refractive index is modified spatially, enabling magnification and reflective modes without additional electronic components.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If conventional mirrors are used, then the structure is simple, but they suffer from excessive glare, limited field of view, and aerodynamic drag

Engineering Contradiction:
ImprovestructureVSAvoidglare and aerodynamic drag
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent employs parameter changes by utilizing the voltage-dependent refractive index of liquid crystals. By adjusting the voltage applied to different regions, the optical properties (refractive index) are dynamically changed, enabling the mirror to reduce glare and improve field of view while maintaining a simple overall structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies dynamics by making the optical properties of the mirror adjustable through voltage control. The liquid crystal layer can dynamically change its refractive index in response to applied voltage, allowing the mirror to adapt to different viewing conditions and reduce aerodynamic drag, unlike static conventional mirrors.

Inventive Principle:
Principle #15Dynamics

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

Ensures continuous mirror functionality by maintaining reflective mode with adjustable magnification, even when the display is inactive, enhancing safety and convenience without relying on electronic components.

Implementation Method 1

the liquid crystal molecules in the liquid crystal layer change their orientation

Methodology Applied
Scientific EffectLiquid crystal orientation change: Liquid Crystals

Implementation Method 2

the refraction index of the liquid crystal layer gradually varies from outer areas towards the center of the liquid crystal layer

Methodology Applied
Scientific EffectRefraction index variation: Refraction

Implementation Method 3

a polarizing filter layer, wherein the second transparent electrode is arranged between the polarizing filter layer and the liquid crystal layer, and a reflective polarizing filter layer, wherein the first transparent electrode is arranged between the reflective polarizing filter layer and the liquid crystal layer

Methodology Applied
Scientific EffectPolarization: Polarisation

Data Source

PatentEP4425243B1Electronic mirror
Publication Date: 2025.07.02 HARMAN BECKER AUTOMOTIVE SYST GMBH
  • EP4425243B1 patent drawingFigure 1~2B
  • EP4425243B1 patent drawingFigure 3~4
  • EP4425243B1 patent drawingFigure 5~6

AI summary

An electronic mirror (24) comprises a liquid crystal cell (30), wherein the liquid crystal cell (30) comprises a first transparent electrode (34a), a second transparent electrode (34b), a liquid crystal layer (36) comprising liquid crystal molecules arranged between the first transparent electrode (34a) and the second transparent electrode (34b), and an AC voltage source (50) configured to apply an alternating voltage across the liquid crystal layer (36) between the first transparent electrode (34a) and the second transparent electrode (34b), wherein, when a voltage is applied across the liquid crystal layer (36), the liquid crystal molecules in the liquid crystal layer (36) change their orientation, and the electronic mirror (24) is configured to apply a varying voltage across the liquid crystal layer (36) which gradually decreases from outer areas towards the center of the liquid crystal layer (36) such that the refraction index of the liquid crystal layer (36) gradually varies from outer areas towards the center of the liquid crystal layer (36). The liquid crystal cell further comprises a polarizing filter layer (32b), wherein the second transparent electrode (34b) is arranged between the polarizing filter layer (32b) and the liquid crystal layer (36), and a reflective polarizing filter layer (32a), wherein the first transparent electrode (34a) is arranged between the reflective polarizing filter layer (32a) and the liquid crystal layer (36).