Vehicle HUD Mirror Positioning for Driver Eye Height Adjustment

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Solution Overview

Problem

Conventional projection systems for heads-up displays in vehicles fail to effectively adjust image projection based on the height of the driver, leading to degraded image viewing and increased costs due to the use of expensive, power-hungry rotatable concave mirrors.

Innovation Solution

An image projection system that includes an image height control module to monitor eye positions and adjust the position of a movable flat mirror using smaller actuation mechanisms, allowing the system to project images at the correct height without changing the angle of incidence, utilizing a flat mirror that is less expensive and consumes less power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a rotatable concave mirror is used to adjust the projection position, then the image can be projected at different positions for different driver heights, but the system becomes more expensive and consumes more power

Engineering Contradiction:
Improveadjustment of image projection positionVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive rotatable concave mirror with a much cheaper movable flat mirror. The flat mirror is significantly less costly to manufacture while still achieving the desired image height adjustment functionality, directly addressing the contradiction between adaptability and manufacturing cost.

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

Solution Approach 2:

The patent extracts the rotational mechanism from the mirror system, separating the image projection function from the height adjustment function. By using a movable flat mirror instead of a rotatable concave mirror, the system eliminates the need for complex rotational mechanisms, reducing both cost and power consumption while maintaining adaptability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If a rotatable concave mirror is used to adjust the projection position, then the image can be projected at different positions, but the system requires a large motor that consumes large amounts of power

Engineering Contradiction:
Improveadjustment of image projection positionVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the expensive rotatable concave mirror with a much cheaper movable flat mirror. The flat mirror is significantly less costly to manufacture while still achieving the desired image height adjustment functionality, directly addressing the contradiction between adaptability and manufacturing cost.

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

Solution Approach 2:

The patent extracts the rotational mechanism from the mirror system, separating the image projection function from the height adjustment function. By using a movable flat mirror instead of a rotatable concave mirror, the system eliminates the need for complex rotational mechanisms, reducing both cost and power consumption while maintaining adaptability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If a rotatable concave mirror is used to adjust the projection position, then the image can be projected at different positions, but the reflected light reaches the eye at different angles causing degraded image viewing

Engineering Contradiction:
Improveadjustment of image projection positionVSAvoidimage viewing quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent extracts the rotational mechanism from the mirror system, separating the image projection function from the height adjustment function. By using a movable flat mirror instead of a rotatable concave mirror, the system eliminates the need for complex rotational mechanisms, reducing both cost and power consumption while maintaining adaptability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of rotating the mirror to change the projection position (which changes the angle of incidence), the patent inverts the approach by moving the mirror linearly to change the projection position while maintaining a constant angle of incidence. This inversion of the adjustment mechanism directly resolves the contradiction between adaptability and image viewing quality.

Inventive Principle:
Principle #13The other way round (Inversion)

4Adaptability or versatility

If the concave mirror rotates to a different orientation, then the projection position changes, but the incidence angle changes causing the image to be viewed outside the target viewing area

Engineering Contradiction:
Improveadjustment of image projection positionVSAvoidimage viewing within target area
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

Instead of rotating the mirror to change the projection position (which changes the angle of incidence), the patent inverts the approach by moving the mirror linearly to change the projection position while maintaining a constant angle of incidence. This inversion of the adjustment mechanism directly resolves the contradiction between adaptability and image viewing quality.

Inventive Principle:
Principle #13The other way round (Inversion)

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 system effectively adjusts image projection based on driver height, ensuring images are viewed within a target area without altering the angle of incidence, reducing costs and power consumption.

Implementation Method 1

a HUD unit projects a light pattern that includes an image off of a set of mirrors, including the movable mirror, towards a windshield. The light pattern reflects off of the windshield towards an eye position of a driver

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4286917B1Automatic eye height adjustment
Publication Date: 2026.04.08 HARMAN INT IND INC
  • EP4286917B1 patent drawingFigure 1
  • EP4286917B1 patent drawingFigure 2
  • EP4286917B1 patent drawingFigure 3

AI summary

Various embodiments include a computer-implemented method comprising determining a height of an eye associated with a user, determining, based on the height of the eye, a target mirror position for a movable mirror to reflect an image on to a reflective surface, wherein the image reflects off of the reflective surface and towards the user at an angle of inclination to reach the user at the height of the eye, the angle of inclination being constant for different heights of the eye, and causing the movable mirror to move to the target mirror position.