Head-up Display Transparency Mask for Parallax Reduction

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Solution Overview

Problem

Current head-up displays suffer from a parallax effect and postcard effect due to sharp transitions in transmittance, leading to reduced user experience and increased system costs, especially in low-light conditions.

Innovation Solution

A transparency mask with low opacity in the central area and increasing opacity in the peripheral area is integrated into the diffuser, reducing the number of surfaces prone to undesired effects and minimizing the parallax effect by softening the transition between illuminated and peripheral areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a transparency mask with sharp transition areas is used, then the postcard effect is reduced, but the parallax effect increases and user experience deteriorates

Engineering Contradiction:
Improvepostcard effectVSAvoidparallax effect
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The transparency mask is designed with spatially varying optical properties: the central area has high transparency to minimize parallax effect, while the peripheral area has low transparency to reduce postcard effect. This local differentiation of quality allows simultaneous optimization of both harmful effects.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The transparency mask is integrated directly into the diffuser component, merging two functional elements into one. This integration reduces the number of interfaces and surfaces where parallax effects could occur, while maintaining the transparency gradient needed to reduce postcard effect.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If multiple separate components (transparency mask and diffuser) are used, then functionality is enhanced, but system complexity and number of surfaces increase

Engineering Contradiction:
ImprovefunctionalityVSAvoidnumber of surfaces
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The transparency mask and diffuser are combined into a single integrated component. This merging reduces the total number of surfaces and interfaces in the optical path, thereby reducing the cumulative parallax effect while maintaining both the transparency gradient functionality and light diffusion functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated component simultaneously performs multiple functions: it acts as both a diffuser (scattering light uniformly) and a transparency mask (creating spatially varying transmission). This multi-functionality reduces system complexity while enhancing overall functionality.

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

3Manufacturing precision

If high contrast ratio displays are used, then image quality is improved, but system costs increase

Engineering Contradiction:
Improveimage qualityVSAvoidsystem costs
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The transparency mask acts as an intermediary optical element that mediates between the display and the observer's eye. By selectively blocking light in the peripheral area, it creates the appearance of a darker background without requiring the display itself to have high contrast ratio, thus reducing display cost while maintaining image quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 improves user perception by attenuating the postcard effect and reducing system costs, allowing the use of lower contrast ratio displays, making head-up displays more affordable for a wider range of vehicles.

Implementation Method 1

The transparency mask and the diffuser are a single element. This has the advantage of less surfaces that are prone to cause undesired side effects.

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

The transparency mask has a transparency that is maximum in a middle area, is minimum in an outer area and continuously reduces from the inside to the outside of a transition area placed between middle area and outer area.

Methodology Applied
Scientific EffectOptical transmission: Absorption (EM radiation)

Data Source

PatentEP3462226B1Head-up display with transparency mask
Publication Date: 2024.08.07 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH
  • EP3462226B1 patent drawingFigure 1~3
  • EP3462226B1 patent drawingFigure 4~5
  • EP3462226B1 patent drawingFigure 6~7

AI summary

The invention is directed to a head-up display. The head-up display is provided with an image generator (23), an optical system (25), a transmissive screen (21) and a transparency mask (4) . The transparency mask (4) is arranged close to a display (3) of the image generator (23).