Micromirror Array Lens Focusing for Multi-Depth AR Head-Up Displays

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Solution Overview

Problem

Existing HUD systems are limited in their ability to display multiple virtual images with different focus lengths, leading to eye fatigue and reduced convenience for drivers, especially when dealing with various objects at different distances while driving.

Innovation Solution

The implementation of a freeform variable focusing Micromirror Array Lens System, which allows for individual control of thousands of micromirrors to create an optical surface capable of reflecting off-axis incident light, enabling rapid adjustment of focal lengths and simultaneous display of multiple virtual images with varying focus lengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing HUD systems display multiple virtual images with different focus lengths, then the system can accommodate various objects at different distances, but the driver experiences eye fatigue and reduced convenience

Engineering Contradiction:

Improveability to display multiple virtual images with different focus lengthsVSAvoideye fatigue

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a variable focusing micromirror array lens system that dynamically adjusts focal length in real-time based on the distance to objects of interest. The system transitions from static focus to dynamic focus adjustment, allowing the HUD to adaptively change focal lengths to match the driver's viewing needs, thereby eliminating eye fatigue caused by fixed focus distances

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the optical parameter (focal length) of the micromirror array lens to match the distance of objects the driver is observing. By adjusting the focal length parameter dynamically, the system ensures that virtual images are always formed at the appropriate distance, reducing the accommodative demand on the driver's eyes and preventing eye fatigue

Inventive Principle:

Principle #35Parameter changes

2Speed

If a freeform variable focusing Micromirror Array Lens System is implemented, then rapid adjustment of focal lengths and simultaneous display of multiple virtual images is enabled, but the device complexity increases

Engineering Contradiction:

Improvespeed of focal length adjustmentVSAvoidcomplexity of micromirror array lens system

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The micromirror array lens system serves multiple functions simultaneously: it acts as both a display element and a focusing element, and can generate multiple virtual images at different focal lengths using a single device. This multi-functionality reduces the need for separate optical components for each function, thereby managing complexity while achieving rapid focal length adjustment

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces traditional mechanical focusing mechanisms (such as moving lenses or mirrors) with an electronically controlled micromirror array system. The focal length adjustment is achieved through electronic control of micromirror orientations rather than mechanical movement, enabling rapid focal length changes without complex mechanical structures

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If existing HUD systems use separate segments for near and far display, then different focal length images can be provided, but the system cannot dynamically adapt to real-time distance changes

Engineering Contradiction:

Improveability to provide different focal length imagesVSAvoiddynamic adaptation to real-time distance changes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system transitions from static segmented display to dynamic continuous focal length adjustment. The variable focusing micromirror array lens system can continuously and rapidly adjust its focal length in real-time, allowing the HUD to dynamically adapt to changing object distances as the vehicle moves, rather than being limited to fixed near and far segments

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 enhances the AR-HUD system by providing clear and accurate images at various focal lengths, reducing eye fatigue and improving driver convenience by allowing the system to dynamically adjust focus in real-time with high speed and accuracy.

Implementation Method 1

create an optical surface capable of reflecting off-axis incident light

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS20250138303A1Head up display with displaying plane distance control with freeform variable focusing micromirror array lens system

Publication Date: 2025.05.01 SD OPTICS INC

AI summary

The present invention comprises freeform variable focusing optical component, optical module, focus controller, display unit, display controller and processing unit. With the freeform variable focusing optical component, the augmented reality head up display system of the present invention can overcome limitation on the number of virtual images for various focal length of the system and support visual information to vehicle driver comfortably decreasing the fatigue of eye as reducing the eyes distributed focus change between objects and display.