Vehicle Display Mirror Diffraction Reduction via Refracting Beads

Solution Overview

Problem

Display mirrors for vehicles suffer from diffraction patterns that interfere with visibility, particularly under nighttime driving conditions due to glare from headlights and ambient reflections, which are exacerbated by the use of optical bonding that reduces anti-glare effectiveness.

Innovation Solution

Incorporating refracting beads with a refractive index different from the optical bonding adhesive into the optical bonding layer between the display element and the partially reflective, partially transmissive element to scatter light and reduce diffraction patterns, while maintaining anti-glare functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If optical bonding is used to bond the display element to the partially reflective element, then bonding strength and optical contact are improved, but anti-glare effectiveness deteriorates due to reduced light scattering

Engineering Contradiction:

Improvebonding strengthVSAvoidanti-glare effectiveness

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The optical bonding adhesive is formulated as a composite material containing refracting beads dispersed within the adhesive matrix. This composite structure combines the bonding function of the adhesive with the light-scattering function of the refracting beads, achieving both strong optical contact and maintained anti-glare effectiveness.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The refracting beads are distributed throughout the optical bonding adhesive layer to create localized light-scattering centers. This local addition of scattering functionality allows the bonding interface to maintain both adhesion and anti-glare properties without compromising either function.

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If a smooth optical bonding interface is used, then optical clarity is improved, but diffraction patterns are exacerbated

Engineering Contradiction:

Improveoptical clarityVSAvoiddiffraction patterns

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The refracting beads, which create local optical inhomogeneities that could be considered defects, are intentionally introduced to convert harmful diffraction patterns into beneficial light scattering. The scattered light from point sources reduces the visibility of diffraction patterns while maintaining overall optical clarity.

Inventive Principle:

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

Solution Approach 2:

The refractive index of the optical bonding adhesive is adjusted and matched to the refractive indices of the display element and partially reflective element. This parameter optimization minimizes unwanted reflections and diffraction while the refracting beads provide sufficient light scattering to reduce diffraction pattern visibility.

Inventive Principle:

Principle #35Parameter changes

3Object-generated harmful factors

If the refractive index of the optical bonding adhesive is matched to the display element and partially reflective element, then reflections are reduced, but light scattering is insufficient

Engineering Contradiction:

ImprovereflectionsVSAvoidlight scattering

Core Design Contradiction:

Object-generated harmful factorsVSIllumination intensity

Solution Approach 1:

The optical bonding adhesive is formulated as a composite material containing refracting beads dispersed within the adhesive matrix. This composite structure combines the bonding function of the adhesive with the light-scattering function of the refracting beads, achieving both strong optical contact and maintained anti-glare effectiveness.

Inventive Principle:

Principle #40Composite materials

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 solution effectively reduces or eliminates diffraction patterns, improving mirror performance by scattering light and maintaining high transmission haze, ensuring clear visibility without clouding, even in low reflectance or dim modes.

Implementation Method 1

Incorporating refracting beads with a refractive index different from the optical bonding adhesive into the optical bonding layer between the display element and the partially reflective, partially transmissive element to scatter light and reduce diffraction patterns

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

maintaining high transmission haze, ensuring clear visibility without clouding

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS10632927B2Diffraction pattern reduction

Publication Date: 2020.04.28 GENTEX CORP

AI summary

A display mirror assembly for a vehicle may comprise a display module comprising a display element; a partially reflective, partially transmissive element disposed generally parallel to the display element; optical bonding adhesive having a refractive index disposed between the display element and the partially reflective, partially transmissive element; and a plurality of refracting beads having a refractive index and incorporated in or on the optical bonding adhesive; wherein the display is optically bonded to the partially reflective, partially transmissive element with the optical bonding adhesive.