Phase Control Backlight for Pupil-Concentrated Display

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Solution Overview

Problem

Conventional backlights for displays consume a large amount of power as they project light to enable viewing from any location, leading to inefficient energy usage.

Innovation Solution

A phase control backlight system that includes a light guide with a diffraction grating and a liquid crystal layer, controlled by a controller to alter the phase of light rays, concentrating them at the viewer's pupils, reducing the need to project light across the entire display area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If light is projected across the entire display area to enable viewing from any location, then viewing flexibility is improved, but power consumption increases

Engineering Contradiction:
Improveviewing flexibilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by concentrating light only to the specific locations where viewers' pupils are positioned, rather than illuminating the entire display area uniformly. The light guide system directs light rays to match the spatial distribution of multiple pupils, ensuring that light is delivered only where needed for viewing, thus reducing overall power consumption while maintaining viewing flexibility.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the light distribution pattern adjustable and adaptable to different viewing configurations. The system can dynamically reconfigure light ray directions to accommodate varying pupil positions and viewer arrangements, allowing the display to optimize its light projection pattern based on real-time viewing conditions rather than using a fixed illumination pattern.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If light is concentrated to specific pupil positions, then power consumption is reduced, but viewing flexibility deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidviewing flexibility
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent applies universality by designing a light guide system that can serve multiple viewing configurations simultaneously. The system is capable of directing light to multiple different pupil positions and can adapt to various viewer arrangements, making it universally applicable to different viewing scenarios rather than being limited to a single fixed pattern. This multi-functionality ensures that viewing flexibility is maintained even as power consumption is reduced through targeted light concentration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Area of stationary object

If parallel rays of light are projected from the light guide, then illumination coverage is improved, but energy efficiency deteriorates

Engineering Contradiction:
Improveillumination coverageVSAvoidenergy efficiency
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The patent applies local quality by transitioning from uniform parallel light distribution to localized light concentration. Instead of projecting parallel rays that illuminate the entire display area, the system directs light rays to specific locations corresponding to viewer pupil positions. This localized approach reduces the total amount of light energy required while maintaining adequate illumination coverage at the critical viewing positions.

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

This solution significantly reduces power consumption by directing light only to the viewer's pupils, enhancing energy efficiency and enabling the display of 3D content without the need for special eyewear.

Implementation Method 1

a light guide that includes a diffraction grating. The light guide is configured to receive light rays from the illuminator, and to diffract light rays out of the light guide via the diffraction grating

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

The light guide can be controlled to alter a phase of the light rays as the light rays are guided within the light guide to cause the diffracted light rays to converge

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Data Source

PatentEP2994790B1Phase control backlight
Publication Date: 2017.07.19 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP2994790B1 patent drawingFigure 1
  • EP2994790B1 patent drawingFigure 2
  • EP2994790B1 patent drawingFigure 3

AI summary

This document describes techniques and apparatuses for implementing a phase control backlight. A phase control backlight is configured to concentrate light to each pupil of a viewer of a display to cause images to be displayed to each pupil of the viewer. The phase control backlight can include an illuminator and a light guide that includes a diffraction grating. The light guide is configured to receive light rays from the illuminator, and to diffract light rays out of the light guide via the diffraction grating. In accordance with various embodiments, the light guide can be controlled to alter a phase of the light rays as the light rays are guided within the light guide to cause the diffracted light rays to converge to a concentration point that corresponds to a position in space of each pupil of the viewer.