Head-Up Display Optical Layout for Multi-Depth Virtual Images

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Solution Overview

Problem

Existing head-up display apparatuses face limitations in size and expandability due to the division of screen images and the need for multiple display devices, and they often require a combiner for virtual-image projection, which restricts their flexibility and scalability.

Innovation Solution

A head-up display apparatus that projects multiple virtual images with different perceived depths using a combination of a first projection apparatus with a concave mirror and a second projection apparatus that allows reflected light to pass through and generate distinct display light, enabling the user to perceive multiple virtual images with varying depths and sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a screen image generated by one drawing device is divided into two images, then multiple virtual images can be displayed, but the size of each virtual image is limited

Engineering Contradiction:
Improveability to display multiple virtual imagesVSAvoidsize of each virtual image
Core Design Contradiction:
Adaptability or versatilityVSArea of moving object

Solution Approach 1:

The patent divides the single screen image into multiple regions, with each region corresponding to a different virtual image. The image generation unit segments the original image data into first image data and second image data, which are then projected by separate projection units to form multiple virtual images of different sizes and depths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes the depth dimension by projecting virtual images at different distances from the user. The first virtual image is projected at a first distance and the second virtual image at a second distance, creating a multi-layered display effect that allows larger overall display area while maintaining individual image sizes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of moving object

If two drawing devices are disposed to eliminate the limitation in regard to the size of each virtual image, then larger virtual images can be displayed, but the size of the device increases

Engineering Contradiction:
Improvesize of each virtual imageVSAvoidsize of the device
Core Design Contradiction:
Area of moving objectVSVolume of moving object

Solution Approach 1:

The patent combines multiple projection units into a single integrated display device housing. The image generation unit generates multiple image data streams that are fed to separate projection units, which are then integrated with the combiner and control unit within a compact arrangement, avoiding the need for separate standalone devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single display device performs multiple functions by generating and projecting multiple virtual images simultaneously. The image generation unit creates both first and second image data, which are then projected by respective projection units to form multiple virtual images, making one device replace what would otherwise require multiple separate devices.

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

3Adaptability or versatility

If a self-luminous type display panel is disposed in a reflection member, then a virtual image can be displayed, but the maximum size of the virtual image becomes the actual size of the display panel

Engineering Contradiction:
Improveability to display virtual imageVSAvoidsize of virtual image
Core Design Contradiction:
Adaptability or versatilityVSArea of moving object

Solution Approach 1:

The patent uses projection units to create optical copies of the generated images. Instead of relying on the physical size of a display panel, the system projects image data through optical systems that form virtual images in space, allowing the virtual image size to be determined by the projection geometry rather than the physical display element size.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent transitions from a two-dimensional display panel to three-dimensional virtual image projection. By projecting images at different depths and utilizing the combiner's reflective properties, the system creates virtual images that extend into the depth dimension, allowing larger apparent sizes without increasing the physical display panel area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration provides a high degree of freedom in design and excellent expandability, allowing for larger virtual images and improved flexibility in displaying information without increasing the device's volume.

Implementation Method 1

a concave mirror configured to reflect the first display light and thereby emit reflected light

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a second projection apparatus including a second display-light generation unit configured to let the reflected light pass therethrough and generate second display light

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3919961B1Head-up display device
Publication Date: 2025.02.19 JVC KENWOOD CORP
  • EP3919961B1 patent drawingFigure 1
  • EP3919961B1 patent drawingFigure 2
  • EP3919961B1 patent drawingFigure 3

AI summary

A head-up display apparatus (10) projects a plurality of virtual images of which depths perceived by a user with respect to a virtual-image display unit (WS) disposed in front of the user are different from each other. The head-up display apparatus (10) includes a first projection apparatus (101) and a second projection apparatus (102). The first projection apparatus (101) includes a first display-light emitting unit (110) configured to emit first display light, and a concave mirror (130) configured to reflect the first display light and thereby emit reflected light thereof, and is configured to enable the user to perceive a first virtual image by projecting the reflected light onto a virtual-image display unit (WS). The second projection apparatus (102) includes a second display-light generation unit (140) configured to let the reflected light pass therethrough and generate second display light different from the first display light, and is configured to enable the user to perceive a second virtual image by projecting the generated second display light onto the virtual-image display unit (WS).