Polarization Volume Grating for Low-Loss Polarized Light Conversion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Optical systems that use unpolarized light sources face significant intensity loss when converting to polarized light, leading to increased power consumption and reduced battery life in mobile devices, and existing solutions require more space than available on smaller devices.

Innovation Solution

A thin-film polarization converter comprising a polarizing beam splitter and a polarization volume grating, which splits unpolarized light into orthogonally polarized components and converts one component without intensity loss, allowing for efficient conversion of unpolarized light to polarized light in a compact form.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional polarizing beam splitters are used to convert unpolarized light to polarized light, then polarization conversion is achieved, but over 50% of light intensity is lost

Engineering Contradiction:
Improvelight intensity lossVSAvoidpolarization conversion efficiency
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The invention segments the polarization conversion process into two distinct stages: first, a polarizing beam splitter divides unpolarized light into two orthogonal polarized beams (separating the function of polarization separation), then a polarization grating converts one polarized beam to the orthogonal polarization state (adding the conversion function). This segmentation allows each component to perform its specialized function with high efficiency, avoiding the 50% intensity loss of conventional single-stage polarizers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The polarization grating acts as an intermediary component between the polarizing beam splitter and the final polarized output. It receives the polarized light from the beam splitter and mediates the polarization state conversion, enabling the system to achieve both high intensity preservation and effective polarization conversion that neither component could achieve alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If traditional polarization conversion components are used, then polarization conversion is achieved, but the device size increases beyond what is available on mobile devices

Engineering Contradiction:
Improvepolarization conversion capabilityVSAvoiddevice volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The invention merges the polarization separation function of the polarizing beam splitter with the polarization conversion function of the polarization grating into a single integrated optical path. This combination eliminates the need for separate, bulky components and allows the system to achieve full polarization conversion capability in a compact configuration suitable for mobile devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The polarization grating is implemented as a thin-film component that can be integrated into compact optical systems. This thin-film approach replaces traditional bulky polarization conversion components, enabling the system to maintain full functionality while dramatically reducing the overall device volume for mobile applications.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution achieves a high intensity preservation of over 95% of the original light, enabling longer battery life in mobile devices and compact design suitable for smaller devices, while maintaining brightness and reducing power usage.

Implementation Method 1

a polarization volume grating configured to receive the light of the first polarization state and the light of the second polarization state, transmit the light of the first polarization state without changing the light of the first polarization state to a different polarization state

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

convert the light of the second polarization state to the first polarization state

Methodology Applied
Scientific EffectPolarization conversion: Polarisation

Implementation Method 3

a polarizing beam splitter configured to split the unpolarized light into light of a first polarization state and light of a second polarization state

Methodology Applied
Scientific EffectPolarization splitting: Polarisation

Data Source

PatentEP4179367B1Polarization conversion using polarization volume grating
Publication Date: 2024.07.31 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP4179367B1 patent drawingFigure 1~2
  • EP4179367B1 patent drawingFigure 3~4
  • EP4179367B1 patent drawingFigure 5

AI summary

One example provides an optical device, comprising a light source configured to output unpolarized light, a polarizing beam splitter configured to split the unpolarized light into light of a first polarization state and light of a second polarization state and a polarization volume grating configured to receive the light of the first polarization state and the light of the second polarization state, and transmit the light of the first polarization state without changing the light of the first polarization state to a different polarization state, and convert the light of the second polarization state to the first polarization state, thereby forming polarized output light.