See-Through Display Optics Using Light Traps for Higher Contrast

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Solution Overview

Problem

Head-mounted displays (HMDs) with see-through views are affected by stray light, which reduces image sharpness and contrast, causing black areas to appear gray and degrading the see-through view due to combined environmental and displayed image light.

Innovation Solution

Implementing optical designs with light traps and polarized light management systems to redirect and absorb stray light, ensuring high contrast and dark areas in the displayed image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If see-through optics are used in HMDs, then environmental visibility is improved, but stray light reduces image sharpness and contrast

Engineering Contradiction:

Improveenvironmental visibilityVSAvoidimage sharpness and contrast

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes stray light from the optical path using light traps positioned at strategic locations within the HMD optics. These light traps capture and absorb stray light before it can reach the user's eye, effectively separating the harmful stray light from the useful display and environmental light paths.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces polarizing filters as intermediary elements in the optical path. These polarizers selectively manage light polarization states to reduce stray light while maintaining the see-through view. The polarizing filters act as mediators that differentiate between desired light paths (display and environmental) and unwanted stray light.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If stray light is present in the optics, then the see-through view combines environmental and displayed light, but black areas appear gray and contrast is reduced

Engineering Contradiction:

Improvesee-through view combinationVSAvoidblack area darkness and contrast

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of stray light into a beneficial outcome by using light traps that specifically target and absorb stray light wavelengths. The light traps are designed to capture stray light that would otherwise degrade image quality, transforming the problem of stray light into an opportunity to enhance contrast and black level performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies local quality improvements by positioning light traps at specific locations within the optical path where stray light is most problematic. Rather than uniformly treating all light, the solution selectively addresses stray light in critical areas while preserving the see-through view and display quality in other regions.

Inventive Principle:

Principle #3Local quality

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

Enhances image clarity and contrast by minimizing stray light, providing sharp black areas and improved see-through visibility in HMDs.

Implementation Method 1

light traps and polarized light management systems to redirect and absorb stray light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

polarized light management systems to redirect and absorb stray light

Methodology Applied

Scientific EffectPolarization: Polarisation

Data Source

PatentUS12386186B2See-through computer display systems

Publication Date: 2025.08.12 OSTERHOUT GROUP INC

AI summary

Aspects of the present invention relate to providing see-through computer display optics.