Switchable Rearview Mirror Anti-Reflection Coating

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Solution Overview

Problem

Existing rearview mirror assemblies with switchable reflective elements still experience significant glare reflections, particularly from the front and rear substrate interfaces, which interfere with the displayed image, even in the transmissive mode, causing issues like double imaging and reduced visibility.

Innovation Solution

The implementation of a switchable reflective element with anti-reflection coatings or prisms on the front and rear sides to minimize reflections, with anti-reflection coatings reducing interface reflections and prisms redirecting unwanted light away from the driver's view.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a switchable reflective element is used in rearview mirror assembly, then the mirror can switch between reflective mode and transmissive mode for displaying images, but significant glare reflections from substrate interfaces interfere with the displayed image

Engineering Contradiction:

Improvemode switching capabilityVSAvoidglare reflections

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

An anti-reflection coating is applied to the substrate interfaces of the switchable reflective element to act as an intermediary layer that reduces glare reflections. This coating mediates between the substrate and ambient light, minimizing harmful reflections while preserving the mode switching capability and image display function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If anti-reflection coatings are applied to reduce interface reflections, then glare is reduced, but the device complexity increases

Engineering Contradiction:

Improveinterface reflectionsVSAvoidcoating structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The anti-reflection coating modifies the optical parameters of the substrate surface by changing the refractive index gradient at the interface. This parameter change reduces reflection coefficients without requiring complex structural modifications, thereby reducing glare while maintaining relatively simple device architecture.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If prisms are added to redirect unwanted light, then glare reflections are reduced, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improveunwanted lightVSAvoidassembly process

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The prisms are integrated directly into the substrate structure of the switchable reflective element, merging the light redirecting function with the existing substrate. This combination eliminates the need for separate assembly steps and reduces manufacturing complexity while effectively redirecting unwanted light away from the driver's view.

Inventive Principle:

Principle #5Merging (Combining)

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 glare reflections to nearly imperceptible levels, enhancing the clarity of the displayed image by minimizing reflections from the substrate interfaces and ambient light, improving visibility and reducing double imaging issues.

Implementation Method 1

an anti-reflection coating provided on at least one of the front and rear sides of the switchable reflective element

Methodology Applied

Scientific EffectAnti-reflection coating: Anti-Reflective Coating

Implementation Method 2

a first prism provided on at least one of the front and rear sides of the switchable reflective element; and a second prism, wherein the first and second prisms are provided on opposite sides of the switchable reflective element

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS9637054B2Switchable rearview mirror element with anti-reflection mechanisms for use with a display

Publication Date: 2017.05.02 GENTEX CORP

AI summary

The embodiments described herein generally relate to a rearview mirror assembly for a vehicle. More particularly, they relate to a rearview mirror assembly including a switchable reflective element and a display. The switchable reflective element is a type that is selectively switchable between a reflective mode and a transmissive mode. The display is positioned behind the switchable reflective element for displaying images through the switchable reflective element when in the transmissive mode. The rearview mirror assembly may further include either an anti-reflection coating provided on at least one of the front and rear sides of the switchable reflective element, or first and second prisms provided on opposite sides of the switchable reflective element.