Head-Up Display Diffuser With Polarizing Element For Brightness Control

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Solution Overview

Problem

Existing head-up displays for vehicles face challenges in varying the brightness of projected images effectively, particularly in adapting to different driving conditions, and this can lead to mechanical complexity and premature aging of components.

Innovation Solution

Incorporating a polarizing element within the diffuser of the image-forming device, combined with a variable polarization element, allows for adjustable light beam attenuation, simplifying the mechanical design and reducing the average light intensity on the diffuser, thus extending its lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a variable polarization element is used to adjust brightness, then brightness adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvebrightness adaptabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the variable polarization element with the diffuser into a single integrated component. The diffuser incorporates a polarization layer that works in conjunction with the variable polarization element, merging two previously separate functions (diffusion and polarization control) into one unified structure, thereby reducing device complexity while maintaining brightness adaptability

Inventive Principle:
Principle #5Merging (Combining)

2Illumination intensity

If high light intensity is used for bright image projection, then image brightness is improved, but diffuser aging accelerates

Engineering Contradiction:
Improveimage brightnessVSAvoiddiffuser lifespan
Core Design Contradiction:
Illumination intensityVSDuration of action of stationary object

Solution Approach 1:

The patent employs a scanning mechanism that periodically directs the light beam across different regions of the diffuser rather than continuously illuminating the entire diffuser at high intensity. This periodic scanning action reduces the cumulative light exposure on any single point of the diffuser, thereby extending its lifespan while still achieving bright image projection through the concentrated light beam

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies polarization control locally at specific regions of the diffuser where the light beam interacts with the polarization layer. By concentrating the polarization effect at the beam-diffuser interface rather than uniformly across the entire diffuser, the system achieves effective brightness control while minimizing overall light exposure and aging of the diffuser material

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 solution enables flexible brightness adjustment while reducing mechanical complexity and prolonging the lifespan of the diffuser by minimizing exposure to high light intensities, enhancing the overall performance and reliability of the head-up display.

Implementation Method 1

the diffuser comprises a polarizing element filtering the light passing through the diffuser

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

an element designed to impart a variable polarization to the light beam

Methodology Applied
Scientific EffectLiquid crystal polarization: Liquid Crystals

Data Source

PatentEP3329318A1Device for forming an image and head-up display comprising a device of this kind
Publication Date: 2018.06.06 VALEO COMFORT & DRIVING ASSISTANCE

AI summary

An image-forming device for a head-up display comprises a diffuser (12), a scanning unit (14) designed to generate a light beam scanning a diffuser (12) surface, and an element (20) designed to induce variable polarization in the light beam. The diffuser (12) comprises a polarizing element (22) filtering the light passing through the diffuser (12). The invention also relates to a head-up display comprising a device of this type.