Polarization Rotator for Flicker-Free 3D Projection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Single-projector three-dimensional projection systems suffer from visible artifacts such as flicker, which are not effectively addressed in prior art designs, necessitating an improved system that reduces or eliminates these artifacts.

Innovation Solution

A single-projector imaging system is configured to deliver dual-frame, three-dimensional imagery using a combined beam with diverse polarization orientations, where light sources have different polarizations, and a polarization rotator selectively alters the polarization state between frames to ensure both eyes receive information from both perspectives simultaneously, reducing flicker and maintaining high-quality color representation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single projector is used to deliver three-dimensional images, then device complexity is reduced, but visible artifacts such as flicker are introduced

Engineering Contradiction:

Improveprojector system complexityVSAvoidflicker artifacts

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the light output into multiple polarization states (first polarization state and second polarization state) that are selectively applied to different frames. This segmentation allows the single projector to deliver distinct images to different eyes through polarization filtering, reducing flicker by ensuring each eye receives continuous information from its designated polarization state.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the polarization parameter of the light between frames by selectively applying first and second polarization states. This parameter change enables the system to control which eye receives which image while maintaining continuous light delivery, thereby reducing flicker artifacts while keeping device complexity low.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If polarization states are selectively applied between frames, then flicker is reduced, but device complexity increases due to additional optical components

Engineering Contradiction:

Improveflicker artifactsVSAvoidoptical system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs a dynamic polarization controller that can switch between first and second polarization states in response to control signals corresponding to different frames. This dynamic adjustment allows the system to reduce flicker by ensuring appropriate polarization filtering for each frame while managing optical complexity through controlled, frame-synchronized operations.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If dual-frame imagery is delivered simultaneously to both eyes, then three-dimensional quality is improved, but image refresh frequency requirements increase

Engineering Contradiction:

Improvethree-dimensional image qualityVSAvoidimage refresh frequency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent employs periodic application of first and second polarization states across alternating frames in a synchronized manner. This periodic action ensures that both eyes receive their designated images at appropriate intervals while maintaining standard refresh frequencies, thereby achieving high three-dimensional image quality without requiring doubled refresh rates.

Inventive Principle:

Principle #19Periodic action

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 system effectively produces high-quality, flicker-reduced three-dimensional images at standard frequencies like 60 Hz without the need for double the projection frequency, ensuring continuous imaging with minimal perceived flicker.

Implementation Method 1

a polarization rotator selectively alters the polarization state between frames

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 2

a light combiner configured to combine light received from each of the plurality of light sources into a combined beam

Methodology Applied

Scientific EffectLight combination:

Data Source

PatentUS8870381B2Mixed polarization imaging system for three-dimensional projection and corresponding methods

Publication Date: 2014.10.28 MICROVISION INC

AI summary

An imaging system (300) configured to reduce perceived flicker in three-dimensional images is provided. The imaging system (300) can include a plurality of light sources (305,306,307), a light combiner (302), a light modulator (303) and a polarization rotator (301). The light combiner (302) combines light received from each of the light sources into a combined beam (304). A first light portion (313) in the combined beam has a first light portion polarization state that is different from a second light portion polarization state of a second light portion (314). The light modulator (303) produces images by modulating the combined beam (304) along a projection surface (316). The polarization rotator (301) selectively rotates a polarization state of the combined beam (304) in synchrony with an image refresh cycle of the imaging system. A circular polarizer (1004) can be used to transform linear polarization states to circular polarization states.