Display Polarization Control for Windshield Reflection Reduction

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Solution Overview

Problem

In vehicles and other optical arrangements, reflections from optically transmissive materials, such as windows, cause distractions due to bright internal display reflections, and existing solutions are either ineffective or costly to implement.

Innovation Solution

A method using optical retarders to control the polarization state of light output from a display panel, specifically aligning it to minimize reflections by making light p-polarized relative to the plane of incidence, thereby reducing reflectivity at surfaces of optically transmissive materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If display devices with highly directional output are used to minimize reflections, then reflection control is improved, but device complexity and manufacturing cost increase due to additional components

Engineering Contradiction:

Improvereflection controlVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the polarization state parameter of the light output from the display device. By using optical retarders to transform the polarization state to align with the plane of incidence, the reflectivity is reduced without adding complex mechanical or structural components. This parameter-based solution resolves the contradiction by achieving reflection control through optical property modification rather than structural complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

While not directly changing color, the patent applies a similar principle by changing the polarization state of light, which is an optical property analogous to color. The optical retarders modify the polarization characteristics of the light, enabling reflection control without requiring additional mechanical components or complex device architecture.

Inventive Principle:

Principle #32Color changes

2Object-affected harmful factors

If optical retarders are used to control polarization state, then reflection control is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvereflection controlVSAvoidease of manufacture

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent merges the reflection control function with the existing display device structure by integrating optical retarders into the display assembly. Rather than adding separate complex systems, the retarders are combined with the display panel and existing optical components, simplifying the manufacturing process while achieving effective reflection control through polarization management.

Inventive Principle:

Principle #5Merging (Combining)

3Illumination intensity

If polarization state is aligned to minimize reflections, then visibility is improved, but optical path complexity increases

Engineering Contradiction:

ImprovevisibilityVSAvoidoptical path complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent introduces optical retarders as intermediary elements between the display panel and the external environment. These retarders mediate the polarization state of the light, transforming it to reduce reflections on transmissive surfaces. The intermediaries enable visibility improvement without requiring complex optical paths, as the retarders are thin-film components that can be integrated into the existing display structure.

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

Effectively minimizes reflections from both windshield and side windows, improving visibility for drivers and passengers by reducing glare without the need for additional costly components.

Implementation Method 1

a display panel arranged to output light that has a predetermined polarization state

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 2

this method makes use of the reflection sensitivity of linearly polarized light resulting from Fresnel reflection at the surface

Methodology Applied

Scientific EffectFresnel reflection: Fresnel Diffraction

Data Source

PatentUS12117621B2Control of reflections of a display device

Publication Date: 2024.10.15 REALD SPARK LLC

AI summary

Reflections from a display device are controlled using retarders arranged on the output side of a display panel which outputs light with a predetermined polarization state. First and second planes of incidence are defined in respect of first and second rays of light output from the device and first and second normals to first and second surfaces of optically transmissive material at first and second points at which the first and second rays of light are reflected. The retarders are selected to cause the polarization state of the first ray to be linearly polarized in a direction that is in the first plane of incidence, and to cause the polarization state of the second ray to be linearly polarized in a direction that is in the second plane of incidence. The reflections from the surfaces are minimized because for both surfaces the polarization direction is in-plane.