Light Guide Incident Face Geometry for Uniform Light Coupling

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Solution Overview

Problem

Conventional light guide devices have uniform light intensity distribution issues due to planar incident end surfaces, leading to inefficient light transmission and distribution.

Innovation Solution

The light guide device features a light incident end with multiple angled or twisted light incident faces, each with a first and second edge displaced along the axis, allowing for non-perpendicular light entry and improved light intensity distribution through total reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a planar incident end surface is used, then the device structure is simple and easy to manufacture, but the light intensity distribution is non-uniform and optical efficiency is poor

Engineering Contradiction:
Improveease of manufactureVSAvoidlight intensity distribution
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The incident end surface is segmented into multiple light incident faces (first, second, third, and fourth light incident faces) arranged around the optical axis. Each face is inclined at different angles relative to the optical axis, creating distinct light reception zones that collectively achieve uniform light intensity distribution across the light guide device cross-section.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light incident faces are designed with asymmetric inclination angles relative to the optical axis. Specifically, the first and second light incident faces are inclined at a first angle, while the third and fourth light incident faces are inclined at a second angle different from the first angle. This asymmetric angular configuration optimizes light distribution uniformity while maintaining manufacturing feasibility through rotational symmetry.

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If a planar incident end surface is used, then the manufacturing process is simple, but the optical efficiency and light transmission are insufficient

Engineering Contradiction:
Improveease of manufactureVSAvoidoptical efficiency
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

Different regions of the incident end are assigned different optical properties through the inclined light incident faces. Each face is optimized for specific light reception directions and angles, with the inclination angles carefully selected to maximize light coupling efficiency into the light guide device while maintaining overall manufacturing simplicity through the modular face structure.

Inventive Principle:
Principle #3Local quality

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

This design enhances optical efficiency by achieving a more uniform light intensity distribution and improved light transmission compared to conventional devices with planar incident end surfaces.

Implementation Method 1

the light travels primarily by total reflection

Methodology Applied
Scientific EffectTotal reflection: Total Internal Reflection

Data Source

PatentEP3415814B1Light guide device, lighting apparatus and motor vehicle
Publication Date: 2023.09.27 FOSHAN ICHIKOH VALEO AUTO LIGHTING SYST
  • EP3415814B1 patent drawingFigure 1
  • EP3415814B1 patent drawingFigure 2~3
  • EP3415814B1 patent drawingFigure 4

AI summary

Embodiments of the present invention provide a light guide device, a lighting apparatus, and a motor vehicle. The light guide device includes: a light incident end configured to receive an incident light, wherein the light incident end has at least one light incident face and each light incident face has a first edge and a second edge that are displaced from each other in a direction along an axis of the light guide device. The light guide device can improve the uniformity and efficiency of incident light coupling of the light guide device.