Head-Up Display Optical Layout for Large Virtual Images

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Solution Overview

Problem

Existing head-up displays are limited in generating large images, and there is a need for a more compact and efficient design that minimizes distortion and optical axis issues.

Innovation Solution

A head-up display comprising a housing with a screen and an image generating part that includes an optical module with a concave mirror for magnifying image light, a projection optical module with adjustable mirrors, and an illumination optical module with a dual-band mirror and fly-eye lens to create a large virtual image, while minimizing the display's size and distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional head-up display uses a display panel and mirrors to project image light, then the driver can perceive virtual images, but the image size is limited and the device becomes complex

Engineering Contradiction:
Improveimage sizeVSAvoiddevice complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent extracts the light source function from the display panel, using a separate illumination optical module with multiple light sources to illuminate the display panel. This separation allows the display panel to focus on image generation while the illumination module handles lighting, enabling larger image sizes without proportionally increasing overall device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a nested structure where the display panel is positioned within the housing, mirrors are arranged within the optical path, and the illumination optical module is integrated into the main body. This nesting allows multiple components to occupy overlapping or adjacent spaces, achieving large image projection without linearly increasing device footprint

Inventive Principle:
Principle #7Nested doll (Nesting)

2Area of stationary object

If the head-up display uses multiple mirrors and optical components to generate large images, then image size increases, but optical axis distortion and manufacturing precision requirements increase

Engineering Contradiction:
Improveimage sizeVSAvoidoptical axis alignment precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent introduces adjustable mirrors with position adjustment mechanisms that can dynamically adjust the reflection angles and optical paths. This dynamic adjustability compensates for manufacturing tolerances and alignment variations, reducing the stringency of initial manufacturing precision requirements while maintaining large image quality

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses the display panel as an intermediary element between the illumination optical module and the projection mirrors. The display panel acts as a spatial light modulator that can be precisely positioned and oriented, serving as a reference plane that simplifies the alignment requirements for the surrounding optical components

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If the head-up display uses a compact optical system with adjustable mirrors, then the device size is minimized, but the complexity of mirror position adjustment mechanisms increases

Engineering Contradiction:
Improvedisplay sizeVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent divides the adjustment system into independent adjustment mechanisms for each mirror (first mirror, second mirror, third mirror), where each mechanism can be optimized and controlled separately. This segmentation allows the compact optical system to maintain adjustability without requiring a single complex centralized control mechanism

Inventive Principle:
Principle #1Segmentation

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 design enables the generation of large virtual images with minimal distortion by using a compact and adjustable optical system, allowing for the integration of multiple displays in vehicles, including wide hover screens for drivers and large-screen infotainment displays for passengers.

Implementation Method 1

a projection optical module that projects the image light generated by the optical module onto a screen

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The projection optical module comprises a concave mirror that magnifies the image light onto a screen

Methodology Applied
Scientific EffectMagnification: Lens

Implementation Method 3

a polarizing film transmitting the first linearly polarized light reflected by the inner mirror and reflecting a second linearly polarized light in a second direction orthogonal to the first direction

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 4

a phase retardation mirror disposed outside the inner space and converting the phase of the first linearly polarized light reflected by the inner mirror and then transmitting the polarizing film into a second linearly polarized light

Methodology Applied
Scientific EffectPhase retardation: Birefringence

Data Source

PatentEP4681962A1Head-up display
Publication Date: 2026.01.21 LG ELECTRONICS INC
  • EP4681962A1 patent drawingFigure 1~2
  • EP4681962A1 patent drawingFigure 3
  • EP4681962A1 patent drawingFigure 4

AI summary

A head-up display according to the present embodiment a main body comprising a housing disposed between a top cover and a bottom cover, a screen accommodated in the housing, and a dust cover disposed over the screen; and an image generating part disposed in the main body. The image generating part comprises an optical module that generates and projects image light; a projection optical module that projects image light generated by the optical module onto the screen. The optical module comprises an image generator that generates image light. The projection optical module comprises a concave mirror that expands the image light onto the screen. The image generating part projects the image generated by the image generator onto the screen via the concave mirror.