Optical Waveguide Aperture Control for Larger HUD Eyeboxes

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Solution Overview

Problem

Conventional head-up displays have limited eyebox sizes due to the size of the optical unit, and using lasers as light sources requires precise assembly, leading to complex systems with increased weight, cost, and interference issues.

Innovation Solution

A device with a microscanner and optical components, including a microlens array, to direct light into different solid angle ranges and achieve a field-point-dependent aperture, ensuring homogeneous illumination of the eyebox using lasers as light sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If lasers are used as light sources to improve illumination efficiency, then illumination intensity is improved, but system complexity increases due to precise assembly requirements

Engineering Contradiction:
Improveillumination efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent segments the aperture control function into multiple movable segments that can be independently adjusted. This allows the complex aperture assembly to be divided into manageable parts, reducing assembly complexity while maintaining precise control over the laser beam aperture for efficient illumination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces movable segments that can dynamically adjust the aperture size and position. This dynamic adjustment capability allows the system to optimize illumination efficiency for different viewing conditions without requiring a completely different assembly for each scenario, thereby reducing overall system complexity.

Inventive Principle:
Principle #15Dynamics

2Illumination intensity

If complex systems are used to create variable aperture for uniform illumination, then illumination uniformity is improved, but weight increases

Engineering Contradiction:
Improveillumination uniformityVSAvoidsystem weight
Core Design Contradiction:
Illumination intensityVSWeight of moving object

Solution Approach 1:

The aperture is divided into multiple lightweight movable segments rather than using a single heavy complex mechanism. Each segment can be independently positioned to achieve uniform aperture filling, providing the needed illumination uniformity with significantly reduced weight compared to traditional complex variable aperture systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the aperture parameters (size, shape, position) by moving discrete segments rather than using a complex continuous adjustment mechanism. This parameter control approach achieves uniform illumination while keeping the system lightweight and simple.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If complex systems with multiple components are used to realize variable aperture, then aperture control precision is improved, but device complexity increases

Engineering Contradiction:
Improveaperture control precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The aperture control system is segmented into discrete movable elements that can be independently positioned. This segmentation allows for precise control of the aperture characteristics while keeping each individual component simple, reducing overall system complexity compared to a single complex continuous adjustment mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses dynamically adjustable movable segments to control the aperture. This dynamic approach allows precise aperture control to be achieved through simple mechanical movements of discrete segments, avoiding the need for complex continuous adjustment systems.

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If conventional optical units are used to generate virtual images, then image generation capability is maintained, but eyebox size is limited

Engineering Contradiction:
Improveeyebox sizeVSAvoidoptical unit size
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent changes the aperture parameters (size, shape, position) by moving discrete segments to optimize the light distribution across the eyebox. This parameter control allows the system to maintain a compact optical unit while enlarging the effective eyebox area, improving viewer adaptability without increasing the physical size of the optical components.

Inventive Principle:
Principle #35Parameter changes

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

Enlarges the eyebox and improves illumination uniformity, reducing system complexity and weight while maintaining precise aperture control.

Implementation Method 1

an optical component is arranged in front of a coupling-in region of the optical waveguide, wherein the optical component is configured to direct the light beam into different solid angle ranges

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

The light coupled into the optical fiber is totally reflected at its interfaces and is thus guided within the optical fiber. In addition, a portion of the light is coupled out at numerous positions along the propagation direction

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3807704B1Apparatus for generating a virtual image having field point dependent aperture
Publication Date: 2025.09.10 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH
  • EP3807704B1 patent drawingFigure 1
  • EP3807704B1 patent drawingFigure 2~3
  • EP3807704B1 patent drawingFigure 4

AI summary

The invention relates to an apparatus for generating a virtual image with a scanning image generation. The device has at least one light source (14, 14R, 14G, 14B) for generating a light beam (L1), an imaging unit (1) for generating an image, and an optical waveguide (5) for expanding an exit pupil. An optical component (71) for implementing a field-point-dependent aperture is arranged in front of a coupling region of the optical waveguide (5).