Vehicle Display Symbol Gap Prevents Light Feedback

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Solution Overview

Problem

Existing display devices for vehicles face issues with unwanted light effects and overexposure, particularly when using backlit symbols, which can lead to inhomogeneous illumination and color distortion.

Innovation Solution

A display device featuring a light-transmissive cover layer with a gap between the symbol area and the cover layer, combined with a light-guiding device that directs light to the side of the symbol area, preventing feedback and using a medium like air to prevent total internal reflection, and optionally incorporating a light source for illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light is guided through the cover layer to illuminate the symbol area, then the symbol is visible, but unwanted light effects and overexposure occur

Engineering Contradiction:
Improvesymbol visibilityVSAvoidunwanted light effects
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful light feedback by removing the direct optical path between the cover layer and symbol area. A gap is introduced between these components, eliminating the mechanism that causes total internal reflection and light feedback, thereby removing the harmful effect while preserving the desired symbol illumination.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The gap acts as an intermediary element between the cover layer and symbol area. This intermediate space filled with air or vacuum prevents direct optical interaction, blocking the harmful light feedback path while allowing the light-guiding device to illuminate the symbol area through controlled light paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the cover layer is placed close to the symbol area for compact design, then device complexity is reduced, but light feedback causes overexposure

Engineering Contradiction:
Improvestructural simplicityVSAvoidillumination uniformity
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The harmful optical feedback path is extracted by removing the direct contact between cover layer and symbol area. The gap eliminates the total internal reflection mechanism, preventing overexposure while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If a gap is introduced to prevent light feedback, then unwanted light effects are eliminated, but the distance between symbol area and cover layer increases

Engineering Contradiction:
Improvelight feedback preventionVSAvoidgap distance
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The gap, which initially appears as an unnecessary space increasing device thickness, is converted into a beneficial optical isolator. This air or vacuum gap actively prevents total internal reflection and light feedback, transforming a potential disadvantage into the key mechanism for eliminating unwanted light effects.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 ensures clear visibility of symbols without unwanted light effects, maintains even illumination, and prevents overexposure, allowing for efficient and effective display of symbols in vehicle applications.

Implementation Method 1

a light-guiding device which is shaped to guide light onto a side of the symbol area remote from the cover layer

Methodology Applied
Scientific EffectLight guidance: Waveguide (optics)

Implementation Method 2

Because of the gap, feedback of the light from the cover layer in the direction of the symbol area or a further symbol area arranged adjacent can be prevented

Methodology Applied
Scientific EffectTotal internal reflection prevention: Total Internal Reflection

Data Source

PatentEP3237248B1Display device for displaying at least one symbol, switching device, and method for manufacturing a display device
Publication Date: 2020.01.15 ZF FRIEDRICHSHAFEN AG
  • EP3237248B1 patent drawingFigure 1~2
  • EP3237248B1 patent drawingFigure 3~4
  • EP3237248B1 patent drawingFigure 5~6

AI summary

A display device (100) for displaying at least one symbol has a light-permeable coating (210) and a symbol layer (213) which includes a light-permeable symbol area (216) for a symbol to be displayed by the display device (100) and a light-impermeable area (214) surrounding the symbol area (216). The symbol area (216) is arranged in such a way as to be separated from the coating (210) by a gap (226). A light guiding device (228) is designed to guide light onto a face of the symbol area (216) that faces away from the coating (210).