Headlight Light Guide Layout for Switchable Signlight Control

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Solution Overview

Problem

Existing motor vehicle headlights suffer from issues such as permanent activation of signlight, which can cause glare and negatively impact optical appearance, and are not compatible with modern glare-free high beam systems like ADB, leading to worse ratings.

Innovation Solution

A lighting device with an additional optical device and separate light source for signlight, using light coupling areas between adjacent light guides to create a segmented light distribution above the horizontal 0°-0° line, allowing independent operation of signlight, which can be switched off or dimmed in ADB mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the same light sources are used for both low beam and signlight generation, then the signlight is always activated when the front/low beam module is illuminated, but this causes permanent activation of signlight which can cause glare and negatively impact optical appearance

Engineering Contradiction:
Improvesignlight activation flexibilityVSAvoidglare and optical appearance
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the lighting system into separate functional modules: a low beam module with its own light sources and an additional optical device for signlight generation with separate light coupling areas. This allows independent control of signlight activation from the low beam, resolving the contradiction by enabling selective signlight operation without permanent activation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the signlight generation function from the main low beam light sources by providing a separate additional optical device with dedicated light coupling areas. This extraction allows the signlight to be controlled independently, eliminating the harmful effect of permanent activation while maintaining the ability to generate signlight when needed.

Inventive Principle:
Principle #2Taking out (Extraction)

2Illumination intensity

If signlight is generated from a comparatively small area on the projection device, then the signlight can be generated, but the projection device is perceived as dazzling by oncoming traffic

Engineering Contradiction:
Improvesignlight visibilityVSAvoiddazzling effect on oncoming traffic
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a spatial dimension solution by providing multiple light coupling areas distributed across the additional optical device rather than concentrating light generation in a single small area. This distribution across multiple areas reduces the intensity concentration that causes dazzling effects while maintaining overall signlight visibility.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Loss of information

If the sign light from the low beam module continues to illuminate the masked area in ADB mode, then overhead signs remain visible, but the masking effect is blurred and ratings are worsened

Engineering Contradiction:
Improveoverhead sign visibilityVSAvoidADB masking effectiveness and ratings
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent implements dynamic control by enabling independent switching of the additional optical device for signlight generation separate from the low beam module. This allows the system to adapt dynamically to ADB mode requirements by selectively activating or deactivating signlight based on traffic conditions, maintaining masking effectiveness while preserving overhead sign visibility when appropriate.

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

Enables adaptive control of signlight, reducing glare and improving safety by allowing selective masking of areas, enhancing compliance with rating systems and providing clear visibility for overhead signs.

Implementation Method 1

at least a part of the light fed into the optical guide, which strikes lateral boundary surfaces of the optical guide, is totally reflected at the boundary surfaces

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP4506616B1Lighting device for a motor vehicle headlight and motor vehicle headlight
Publication Date: 2026.03.18 ZKW GRP GMBH
  • EP4506616B1 patent drawingFigure 1
  • EP4506616B1 patent drawingFigure 2
  • EP4506616B1 patent drawingFigure 2a

AI summary

The invention relates to a lighting device (100) for a motor vehicle headlight, comprising an optical body (1) and several light guide elements (2), wherein the light guide elements (2) with their light-emitting surfaces (2b) open into an optical body entry surface (11) opposite an optical body light-emitting surface (10) of the optical body (1). The light guide elements (2) are arranged such that the light-emitting surfaces (2b) of adjacent light guide elements (2) have a greater than zero distance to each other, so that a free area (12) is formed between each two adjacent light guide elements (2) on the optical body entry surface (11). Furthermore, the lighting unit (101) comprises an additional optical device (200), wherein the additional optical device (200) has at least one light coupling area (201) and one or more light coupling areas (202).wherein each light coupling area (201) is assigned at least one additional light source (250), and wherein at least a portion of the light coupled into the additional optical device (250) by an additional light source (250) via a light coupling area (201) propagates in the additional optical device (250) to one or more light output coupling areas (202) and exits the additional optical device (200) there, and wherein at least one, preferably exactly one, light output coupling area (202) is arranged between two adjacent light guide bodies (2) such that light exiting from the light output coupling area (202) can enter the optical body (1) via the free area (12) between the two light guide bodies (2) and propagate in the optical body to the optical body light exit surface (10) of the optical body (1).