Curved Light Guide for Uniform 360-Degree Gauge Illumination

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Solution Overview

Problem

Existing vehicle instrument panel light guides fail to provide uniform illumination to concave gauge surfaces, leading to uneven light distribution and aesthetic issues.

Innovation Solution

A geometrically shaped light guide is designed to correspond with the concave gauge surface, featuring curved ends for receiving light and ribs/surface roughness to distribute light uniformly around the axis of rotation, ensuring 360-degree illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If planar light guides are used for propagating light, then light can be delivered to gauge surfaces, but light distribution becomes uneven on concave surfaces

Engineering Contradiction:

Improvelight distribution uniformityVSAvoidlight guide geometry

Core Design Contradiction:

Illumination intensityVSShape

Solution Approach 1:

The light guide transitions from a planar shape to a curved geometry that conforms to the concave gauge surface. The light guide includes a first curved surface and a second curved surface that match the contours of the concave gauge surface, allowing light to be distributed evenly across the curved illumination surface.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The light guide incorporates light distributing features such as ribs or surface roughness at specific locations to enhance light distribution in areas where the concave surface creates shadowing effects. These localized features ensure uniform illumination across different regions of the gauge surface.

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If light guides do not conform to concave surfaces, then manufacturing is simpler, but illumination coverage is insufficient for 360-degree gauge surfaces

Engineering Contradiction:

Improveillumination coverageVSAvoidlight guide fabrication

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The light guide is formed with curved surfaces that conform to the concave gauge surface, enabling 360-degree illumination coverage. The curved first and second surfaces are designed to match the specific geometry of the gauge surface, ensuring complete coverage while maintaining manufacturability through standard molding processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The light guide serves multiple functions: it propagates light from the light source, distributes light uniformly across the concave surface, and provides structural support for the illumination assembly. This multi-functionality reduces the need for additional components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Illumination intensity

If light is received from a single direction, then the light guide structure is simpler, but 360-degree illumination cannot be achieved

Engineering Contradiction:

Improveillumination angle coverageVSAvoidlight guide structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The light guide utilizes three-dimensional curved surfaces instead of two-dimensional planar surfaces. The first curved surface receives light from one direction while the second curved surface extends the illumination to achieve 360-degree coverage, effectively adding dimensional complexity to resolve the illumination coverage requirement.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The curved geometry of the light guide allows light to be redirected and distributed around the concave gauge surface. The curvature of the first and second surfaces works together to bounce and distribute light uniformly across the entire 360-degree gauge surface from a single light source location.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 solution provides uniform and aesthetically pleasing illumination to the gauge surface, enhancing the visibility and readability of operational parameters on vehicle instrument panels.

Implementation Method 1

A non-planar light guide is provided that enables uniform distribution of light about a gauge surface of a gauge assembly

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The light guide includes ribs or surface roughness to distribute light uniformly around the axis of rotation

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS9937849B2Gauge 360 illumination lightguide

Publication Date: 2018.04.10 CONTINENTAL AUTOMOTIVE SYSTEMS INC

AI summary

A gauge assembly includes a gauge surface and a light guide. The gauge surface includes a concave surface having an illuminable scale. The light guide forms a geometric shape corresponding to the concave surface of the gauge surface. The light guide has ends that curve away from the gauge surface to receive light.