Vehicle Planar Light Guide Deflection Section

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Solution Overview

Problem

Existing vehicle lighting devices with planar light guide bodies suffer from high manufacturing costs and light losses due to total reflection on inner surfaces, resulting in inefficient light emission along a narrow output side.

Innovation Solution

The introduction of a deflection section with two total reflection surfaces arranged in a periscopic manner within the planar light guide body, allowing light to enter the light input side and exit directly to the narrow output side without reflection on the flat surfaces, effectively forming a high-efficiency narrow light beam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a planar light guide body with flat surfaces is used to emit light along a narrow output side, then a linear light emission can be achieved, but light losses occur due to total reflection on the inner sides of the flat surfaces

Engineering Contradiction:

Improvelinear light emissionVSAvoidlight loss

Core Design Contradiction:

ShapeVSLoss of energy

Solution Approach 1:

The light guide body is divided into distinct functional sections: a deflection section with total reflection surfaces that redirects light, and a flat surface portion with flat surfaces that transmits light. This segmentation allows each section to perform its specific function optimally - the deflection section handles light redirection with high efficiency, while the flat surface portion provides the desired linear light emission pattern.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The deflection section acts as an intermediary between the light source and the flat surface portion. It receives light from the light source, redirects it through total reflection at its specialized surfaces, and delivers the light to the flat surface portion for final emission. This intermediary structure eliminates the need for light to undergo total reflection at the flat surfaces, thereby preventing light loss while achieving linear emission.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If a deflection section with ellipsoidal surface is used to deflect light, then light can be redirected towards the narrow side, but manufacturing costs increase

Engineering Contradiction:

Improvelight deflectionVSAvoidmanufacturing cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The deflection surfaces are designed with specific geometric parameters (curvature radii, angles of incidence, relative positions) that can be precisely controlled during manufacturing. By optimizing these parameters, the patent achieves effective light deflection using surfaces that are more compatible with standard manufacturing processes, reducing complexity and cost compared to purely ellipsoidal surfaces.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of making the entire light guide body complex, the patent applies the complex deflection geometry only locally at the deflection section where it is needed. The rest of the light guide body, particularly the flat surface portion, maintains simple geometry that is easy and inexpensive to manufacture. This localized application of complexity minimizes overall manufacturing difficulty while achieving the required light deflection function.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If multiple total reflection surfaces are arranged in periscopic manner, then light losses are reduced and lighting efficiency is enhanced, but device complexity increases

Engineering Contradiction:

Improvelight loss reductionVSAvoiddeflection section structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The deflection section with its multiple total reflection surfaces serves multiple functions simultaneously: it redirects light from the light source, eliminates total reflection losses at the flat surfaces, and creates the desired linear light emission pattern. By combining these functions into a single integrated component, the patent reduces the need for additional separate optical elements, thereby managing device complexity while achieving high lighting efficiency.

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

This configuration reduces light losses and enhances lighting efficiency by eliminating total reflection at the flat surfaces, enabling a high-efficiency, narrow light beam emission along the planar light guide body's output side.

Implementation Method 1

the deflection section has two total reflection surfaces, which are arranged such that the light deflected by the two total reflection surfaces enters in the light input side of the flat surface portion

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS11149914B2Planar light guide lighting device for vehicles

Publication Date: 2021.10.19 HELLA GMBH & CO KGAA

AI summary

A lighting device for vehicles, having a light source unit containing a plurality of light sources for emitting light and having a planar light guide body associated with the light source unit containing a flat surface portion with at least two opposite flat surfaces extending from a light input side of the flat surface portion to a light output side thereof, wherein the light can be coupled out at a narrow side of the light output side for the generation of a light distribution and comprising a deflection section for the deflection of the light emitted by the light source unit in the direction of the narrow side of the flat surface portion coupling out the light.