Optical Field Correction Element with Anti-Reflective Coating

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Solution Overview

Problem

Existing light modules for adaptive driving beams in motor vehicles face issues with achieving sharp contrast between illuminated and dark areas due to parasitic radiation caused by concave input faces of optical field correction elements, leading to reduced precision in light emission.

Innovation Solution

Incorporating an antireflection coating on at least a portion of the input and output faces of the optical field correction element, specifically designed to reduce parasitic reflection and increase transmission rates, thereby enhancing the precision of light emission and contrast in adaptive lighting systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a concave entrance face is used in the field correction optical element, then the light sources can be correctly focused and imaged by the projection optics, but parasitic radiation occurs due to reflection off the concave surface, reducing the sharpness of the dark band and contrast between illuminated and dark areas

Engineering Contradiction:
Improvefocus precisionVSAvoidparasitic radiation
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful reflection effect of the concave surface into a beneficial one by applying an anti-reflective coating. The coating transforms the parasitic radiation problem into an opportunity to achieve both proper focusing and minimal reflection, allowing the concave geometry to serve its focusing function without generating harmful stray light.

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

Solution Approach 2:

The patent changes the optical parameters of the entrance face by applying an anti-reflective coating with specific refractive index properties. This modification alters the reflection and transmission characteristics of the surface, reducing parasitic radiation while maintaining the focusing capability provided by the concave geometry.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If an anti-reflective coating is applied to the entrance face, then parasitic radiation is reduced and transmission rate increases, but the complexity of manufacturing the optical element increases

Engineering Contradiction:
Improveparasitic radiationVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies an anti-reflective coating to modify the optical parameters of the entrance face. While this adds a manufacturing step, the coating process is a standard industrial technique that can be integrated into existing production lines, making the increase in manufacturing complexity acceptable given the significant improvement in optical performance.

Inventive Principle:
Principle #35Parameter changes

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 antireflection coating significantly reduces parasitic radiation, improving the transmission rate of light rays and achieving a sharper contrast between illuminated and dark areas, thus enhancing the performance of adaptive lighting modules.

Implementation Method 1

at least a portion of the entry face is coated with an anti-reflective coating capable of reducing the reflection of a portion of the light rays by this entry face

Methodology Applied
Scientific EffectAnti-reflective coating: Anti-Reflective Coating

Implementation Method 2

the light beam which, after refraction at the output face of the corresponding light guide

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3421875B1Light module comprising an optical field-correction element
Publication Date: 2022.08.31 VALEO VISION SA
  • EP3421875B1 patent drawingFigure 1
  • EP3421875B1 patent drawingFigure 2
  • EP3421875B1 patent drawing

AI summary

A field correction optical element, configured for arrangement in an adaptive lighting device through light rays emitted by a plurality of light sources, comprises a light ray inlet face (21) and a light ray outlet face (22). At least a portion of the inlet face (21) is coated with an anti-reflective coating (AR1) suitable for increasing the transmission rate of light rays through the optical element.