Vehicular Headlight Lens With Rearward Glare Reflection

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Solution Overview

Problem

Existing vehicular headlights suffer from the generation of glare light due to internal reflections within the lens, which can cause discomfort to oncoming drivers.

Innovation Solution

The lens design incorporates a convex emission surface with a concave upper edge area and a rearward reflective portion that internally reflects glare-inducing light rearward, while maintaining a circular appearance and forming auxiliary illuminating patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional lens with smooth emission surface is used, then the headlight structure is simple and easy to manufacture, but internal reflections cause glare light to be emitted upward

Engineering Contradiction:
Improveglare light emissionVSAvoidlens surface structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The emission surface is divided into different regions with different functions: a first region that emits light forward and a second region (upper edge area) with a rearward reflective portion that reflects glare light backward. This local differentiation allows the lens to simultaneously achieve glare suppression and maintain structural simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The rearward reflective portion in the upper edge area converts the harmful internally reflected glare light into a beneficial effect by reflecting it backward toward the reflector, preventing upward emission and transforming a harmful optical path into a useful one that contributes to overall illumination efficiency.

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

2Object-affected harmful factors

If the upper edge area is designed with rearward reflective portion, then glare light is suppressed, but the lens shape becomes more complex

Engineering Contradiction:
Improveupward light emissionVSAvoidemission surface geometry
Core Design Contradiction:
Object-affected harmful factorsVSShape

Solution Approach 1:

Instead of trying to prevent internal reflections from reaching the upper edge area, the invention inverts the approach by providing a rearward reflective portion that actively reflects the internally reflected light backward. This inverted strategy converts the problematic upward-emitting surface into a glare-suppressing feature.

Inventive Principle:
Principle #13The other way round (Inversion)

3Object-affected harmful factors

If the lens redirects internally reflected light rearward, then glare is suppressed, but light distribution efficiency may be reduced

Engineering Contradiction:
Improveglare lightVSAvoidlight distribution efficiency
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The rearward reflective portion converts previously wasted internally reflected glare light into useful illumination by redirecting it backward toward the reflector, which then reflects it forward through the incident surface. This transforms energy that would have been lost to glare into effective forward illumination.

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

Solution Approach 2:

The upper edge area with the rearward reflective portion serves multiple functions: it suppresses glare light emission upward, redirects internally reflected light backward for useful illumination, and maintains the overall circular shape of the emission surface. This multi-functionality ensures no energy is wasted.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design effectively suppresses glare by redirecting internally reflected light away from the vehicle, ensuring a clear view for oncoming traffic while maintaining the headlight's primary illumination function.

Implementation Method 1

the upper edge area has a shape allowing the light entered through the incident surface and directly reached the upper edge area to be internally reflected rearward in the on-board state after being internally reflected toward the incident surface side from the emission surface

Methodology Applied
Scientific EffectInternal reflection: Reflection

Data Source

PatentEP4019829B1Lens for vehicular headlight, and vehicular headlight
Publication Date: 2025.10.01 ICHIKOH IND LTD
  • EP4019829B1 patent drawingFigure 1
  • EP4019829B1 patent drawingFigure 2
  • EP4019829B1 patent drawingFigure 3~4

AI summary

A lens of a vehicular headlight is mounted on a vehicle and includes an incident surface through which light from a light source enters and an emission surface from which light entered from the incident surface is emitted. At an upper edge area including an upper end in an on-board state, the emission surface has a shape allowing a portion of light entered through the incident surface and reached the upper edge area to be internally reflected rearward in the on-board state after being internally reflected toward the incident surface side from the emission surface and internally reflected toward the emission surface side from the incident surface.