Virtual Image Display Device with Concave Mirror Adjustment

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Solution Overview

Problem

Existing head-up display technologies cause significant changes in the depth position of virtual images when adjusting for different user heights due to changes in the focal distance of the concave mirror, leading to astigmatism and potential blurring or discomfort for users.

Innovation Solution

A virtual image display device that includes a display unit, a concave mirror, and a driving mechanism, where the display unit is moved linearly to adjust its distance from the concave mirror and the concave mirror is rotated to change the incidence angle of the image display light, thereby minimizing the change in the depth position of the virtual image when adjusting for different user heights.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the orientation of the concave mirror is changed to adjust for different user heights, then the virtual image can be viewed at different heights, but the focal distance of the concave mirror changes causing the depth position of the virtual image to shift

Engineering Contradiction:

Improveadjustment range for user heightVSAvoiddepth position stability of virtual image

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by simultaneously adjusting multiple parameters: the orientation angle of the concave mirror and the distance between the display unit and concave mirror. This coordinated parameter adjustment compensates for focal distance changes, maintaining virtual image depth position stability while enabling height adaptation for different users.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the distance between the display unit and concave mirror adjustable rather than fixed. This dynamic adjustment allows the system to adapt to changing mirror orientations, ensuring the virtual image remains at a stable depth position regardless of the mirror's angular position.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the concave mirror is rotated to change the incidence angle for height adjustment, then users with different eye heights can view the image, but astigmatism increases causing blurring and discomfort

Engineering Contradiction:

Improveaccommodation for different eye heightsVSAvoidimage quality and focus stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes multiple parameters simultaneously - the incidence angle of the concave mirror and the display unit-to-mirror distance - to compensate for astigmatism. By coordinating these parameter adjustments, the system maintains optimal focus and image quality across different viewing heights, preventing blurring and user discomfort.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the distance from the display unit to the concave mirror is increased, then the field of view and adjustment range improve, but the image brightness and clarity decrease

Engineering Contradiction:

Improvefield of view rangeVSAvoidvirtual image brightness

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent makes the distance between the display unit and concave mirror dynamically adjustable rather than fixed. This allows the system to optimize the balance between field of view and image brightness by adjusting the distance according to the required viewing conditions, ensuring both adaptability and image quality.

Inventive Principle:

Principle #15Dynamics

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 reduces the astigmatic difference and maintains a stable virtual image position for users with varying heights, preventing blurring and discomfort by non-linearly adjusting the distance between the display unit and the concave mirror in response to changes in the focal distance caused by angle adjustments.

Implementation Method 1

a concave mirror that reflects the image display light and projects the image display light toward the windshield

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentEP3828619B1Virtual image display device

Publication Date: 2023.05.17 JVC KENWOOD CORP

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AI summary

A virtual image display device 10 presents a virtual image to a user via a virtual image presentation plate. The virtual image display device 10 includes a display unit 12 that generates an image display light L; a concave mirror 14 that reflects the image display light L and projects the image display light L toward the virtual image presentation plate; and a driving mechanism 20 that changes an orientation of the concave mirror 14 to change an incidence angle ϕ of the image display light L on the concave mirror 14 and change a distance a from the concave mirror 14 to the display unit 12 in accordance with the orientation of the concave mirror 14.