Vehicle Lamp Module Freeform Light Guide for Uniform 3D Lighting

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Solution Overview

Problem

Conventional LED lighting units in vehicle lamps lack the ability to provide 3-dimensional lighting effects with homogeneous brightness while maintaining a thin profile and cost-effective manufacturing, as they often require complex shapes or thick light guides with rough surfaces.

Innovation Solution

A lamp module design featuring a freeform emitting surface on the light guide defined by a specific equation, combined with a projection lens, to achieve uniform light distribution and 3-dimensional effects without increasing thickness or complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the light guide thickness is increased or rough surfaces are applied to improve light homogeneity, then the overall homogeneity of projected light is improved, but the volume of the lamp module increases and manufacturing complexity increases

Engineering Contradiction:
Improvehomogeneity of projected lightVSAvoidvolume of lamp module
Core Design Contradiction:
Illumination intensityVSVolume of moving object

Solution Approach 1:

The patent applies local quality by creating a rough surface only at the light guide-emitting interface where it is most needed for light homogenization, while keeping the outer lens surface smooth. This localized roughness treatment achieves the desired light diffusion effect without requiring the entire lamp module to be thick or complex.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent transitions from a conventional flat 2D light guide interface to a 3D microstructured rough surface with controlled topology. This dimensional change enables effective light scattering and homogenization in a thin profile by utilizing surface topology rather than increasing overall thickness.

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

2Illumination intensity

If the light guide thickness is increased or rough surfaces are applied to improve light homogeneity, then the overall homogeneity of projected light is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improvehomogeneity of projected lightVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The rough surface is applied only at the specific light guide-emitting interface rather than throughout the entire component, reducing material usage and simplifying the manufacturing process while maintaining effective light homogenization.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By using microstructured surface topology instead of increasing thickness, the patent achieves light homogenization through a surface-level solution that is simpler and more cost-effective to manufacture than volumetric modifications.

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

3Shape

If the lens shape is altered to create cavities for 3D effects, then aesthetic appearance is improved, but the projected light becomes non-homogeneous due to scattering from multiple point light sources

Engineering Contradiction:
Improve3-dimensional lighting effectVSAvoidhomogeneity of projected light
Core Design Contradiction:
ShapeVSIllumination intensity

Solution Approach 1:

The rough surface is applied at the light guide-emitting interface before light enters the lens cavity, pre-homogenizing the light distribution. This preliminary action ensures that even though the lens creates 3D visual effects through its cavity shape, the light remaining homogeneous throughout the projection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a microstructured rough surface (3D topology) at the light guide interface to achieve light homogenization, while the lens cavity provides the aesthetic 3D effect. These two 3D features work together rather than interfere with each other.

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

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 ensures uniform brightness and 3-dimensional lighting effects with reduced thickness and manufacturing costs, using transparent thermoplastic polymers for the light guide and lens.

Implementation Method 1

a light guide, arranged downstream of the primary optical device, extending along a longitudinal axis Y that is substantially perpendicular to the X axis, comprising an incident surface configured to receive the rays of the beam of light generated by the LEDs and a body configured to guide said beam of light towards an emitting surface of the light guide

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

where, at each point of the curve, the tangent of the curve forms an angle α with a Z axis that is perpendicular to the X and Y axes, defined by the equation : where : n is the refractive index of the material of the light guide

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

the emitting surface of the light guide is a freeform surface, wherein, in a cross-section along a plane normal to the Y axis the projection of the freeform surface is as a curve defined as a series of points, wherein at each point of the curve, the tangent of the curve forms an angle α with a Z axis

Methodology Applied
Scientific EffectGeometric optics: Geometry

Implementation Method 4

an optical element arranged downstream of the emitting surface of the light guide, comprising an input surface configured to receive the rays of the beam of light emitted by the emitting surface of the light guide and an output surface

Methodology Applied
Scientific EffectLens focusing: Lens

Data Source

PatentEP4686869A1Lamp module for a motor vehicle
Publication Date: 2026.02.04 OPMOBILITY LIGHTING GERMANY GMBH
  • EP4686869A1 patent drawingFigure 1~2
  • EP4686869A1 patent drawingFigure 3~4
  • EP4686869A1 patent drawingFigure 5

AI summary

The invention concerns a lamp module (10). comprising a primary optical device including light sources (16) generating a beam of light (18) propagating along an X axis, a light guide extending along a longitudinal axis Y perpendicular to the X axis, and a projecting lens (40) arranged downstream an emitting surface (30) of the light guide. In a cross-section along a plane normal to the Y axis, the projection of the emitting surface is as a curve. At each point, the tangent of the curve forms an angle a with a Z axis that is perpendicular to the X and Y axes, defined by the equation: where : • n is the refractive index of the material of the light guide and • θ the extreme viewing angle, with respect to the X axis, of the ray of light emitted at the point considered by the emitting surface of the light guide as it exits the output surface (44).