Projector-Based Vehicle HUD Circular Polarizer Contrast

Solution Overview

Problem

Existing head-up display (HUD) technologies face challenges in achieving high energy efficiency and contrast, particularly in high ambient brightness conditions, due to the conflict between image quality and energy efficiency caused by the use of liquid crystal display screens and micro-LED displays, which require high image brightness and costly components.

Innovation Solution

A projector-based field-of-view display device with a contrast element that separates the reduction of ambient light brightness from the projection screen, allowing the projector light to pass undisturbed while attenuating ambient light, using a circular polarizer or metallic coating to achieve high contrast and energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a projection screen with dark absorbent coating is used to improve image quality and contrast, then contrast is improved, but energy efficiency deteriorates due to significant attenuation of projector light

Engineering Contradiction:
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The projection screen is segmented into two functional layers: a highly reflective base layer for energy efficiency and a selective absorbent coating layer for contrast enhancement. This segmentation allows each layer to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The absorbent coating is applied selectively to specific regions or patterns on the projection screen rather than uniformly across the entire surface. This local quality approach ensures that contrast is enhanced only where needed for image quality while maintaining high overall reflectivity for energy efficiency.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If LCD screens with matrix backlight are used to achieve high image brightness, then visibility is improved, but heat management and power consumption deteriorate

Engineering Contradiction:
Core Design Contradiction:
Illumination intensityVSUse of energy by stationary object

Solution Approach 1:

The patent replaces the active LCD matrix backlight system with a passive projection-based system using a DLP chip or similar projector technology. This substitution eliminates the need for high-power backlight LEDs and liquid crystal modulation, dramatically reducing power consumption while maintaining image brightness through efficient light projection onto the specialized screen.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the operational parameters from active light generation (LCD with matrix backlight) to passive light projection and reflection. By using a high-efficiency projector with a specialized reflective screen, the system achieves comparable or superior brightness with significantly lower power consumption and heat generation.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If micro-LED displays are used to achieve high image brightness in transparent windshield areas, then visibility is improved, but cost deteriorates

Engineering Contradiction:
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent employs a projector-based system with a DLP chip or similar cost-effective projection technology instead of expensive micro-LED displays. The projection screen uses standard reflective materials rather than costly transparent display components, significantly reducing manufacturing costs while achieving the required image brightness for windshield integration.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 high energy efficiency and undiminished contrast even in high ambient brightness, suitable for large-area and panoramic virtual image representation on windshields, resolving the conflict between image quality and energy efficiency.

Implementation Method 1

using a circular polarizer or metallic coating to achieve high contrast and energy efficiency

Methodology Applied
Scientific EffectPolarisation: Polarisation

Implementation Method 2

generate a virtual image shown in the field of view of a user via reflection on an at least partially transparent reflection plate

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentUS20240377632A1Projector-Based HUD for a Vehicle Having An Increase In Contrast and Efficiency Via a Circular Polarizer
Publication Date: 2024.11.14
  • US20240377632A1 patent drawing
  • US20240377632A1 patent drawing

AI summary

A projection unit for a field-of-view display device, which is configured to show a virtual image via reflection on a partially transparent reflection plate arranged in the field of view of a user, such as a vehicle window, includes a projector-based image generator having a projector and a projection screen illuminated thereby, wherein the projector is configured to generate a real image on the projection screen and the projection screen is configured to project the resulting light beam bundle in a predetermined shape and direction onto the reflection plate; and a contrast element arranged in relation to the projection screen and configured such that it is only passed by the light beam bundle originating from the projection screen and this is largely without attenuation, and it is passed twice by the ambient light incident on the projection screen and reflected thereon and eliminates it.