Light Guide with Prismatic Grooves for Compact Vehicle Lighting

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Solution Overview

Problem

Saddle-riding type vehicles face challenges in achieving sufficient light emission without increasing the size of the front cover, while minimizing brightness unevenness between adjacent emission faces.

Innovation Solution

A light guide is used that extends diagonally downward from the position light, with a structured face having prismatic grooves that reflect light both upward and forward, allowing for a smaller front cover size while increasing the emission surface area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the illumination lamps are made smaller to reduce the front cover size, then the front cover size is reduced, but the light emission surface area becomes smaller resulting in inadequate light quantity

Engineering Contradiction:
Improvefront cover sizeVSAvoidlight emission surface area
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The light guide extends in multiple directions (width direction, front-back direction, and up-down direction) to create a three-dimensional light emission structure. This allows light to be emitted not only forward but also upward and sideways, effectively increasing the light emission surface area without proportionally increasing the front cover size.

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

Solution Approach 2:

The light guide acts as an intermediary between the illumination lamp and the surrounding space. It receives light from the lamp and redistributes it across multiple emission faces (front end face, upper side face, lower side face), thereby amplifying the effective light emission area without requiring a larger lamp or front cover.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If a light guide and reflectors are used to increase light emission in multiple directions, then the light emission surface area increases, but the front cover size increases

Engineering Contradiction:
Improvelight emission surface areaVSAvoidfront cover size
Core Design Contradiction:
Illumination intensityVSArea of stationary object

Solution Approach 1:

The light guide integrates multiple functions into a single component: it guides light from the illumination lamp, distributes light across multiple emission faces, and replaces the need for separate reflectors. This merging of functions achieves multi-directional light emission without requiring additional space for separate optical components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light guide serves multiple purposes simultaneously: it acts as a light guide, a light distributor, and a light emitter with multiple faces. This multi-functionality allows the system to achieve complex light emission patterns using a single component, thereby avoiding the space requirements of multiple separate components.

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

3Object-affected harmful factors

If the front cover size is reduced to improve aerodynamics, then aerodynamics are improved, but the space available for disposing illumination lamps and optical components is reduced

Engineering Contradiction:
ImproveaerodynamicsVSAvoidspace for components
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The light guide utilizes three-dimensional space efficiently by extending in multiple directions (width, front-back, and up-down directions). This allows the illumination system to maintain adequate component space within a compact front cover, preserving aerodynamic performance while accommodating the necessary optical components.

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

This configuration ensures sufficient illumination is provided without enlarging the front cover, maintaining a compact size and reducing brightness unevenness between emission faces.

Implementation Method 1

a light guide (37) which receives light from the position light (33) and guides the light to emit in multiple directions

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a linear light emitter having a translucent rod-shaped body which has a light incident portion at least at one end thereof and which has, on a peripheral side surface running along an axial direction, light reflecting grooves reflecting incident light from the light incident portion

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2568321B1Saddle-riding type vehicle with light guide used in same
Publication Date: 2021.08.25 YAMAHA MOTOR CO LTD
  • EP2568321B1 patent drawingFigure 1
  • EP2568321B1 patent drawingFigure 2
  • EP2568321B1 patent drawingFigure 3

AI summary

A position light (33) and light guide (37) that serve as a light source are disposed on a front cover (10). The light guide (37) extends in the width direction of the chassis and receives light moving from the position light (33) in the width direction of the chassis. The light guide (37) has a structured face (37B) and emission faces (37U) and (37F). The structured face (37B) has a plurality of optical structures (370). The emission face (37U) is disposed on the opposite side from the structured face (37B), and emits light reflected by the structured face (37B). The emission face (37F) emits light reflected by the structured face (37B). The optical structures (370) are grooves inclined with respect to a width direction (WD), and of the two ends of the optical structures (370), the one disposed on the emission face (37F) side is disposed farther away from the position light (33) than the other end.