Coherent Fiber Bundle Display Layout for Brightness Without Heat Load

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Solution Overview

Problem

Existing display technologies for augmented and virtual reality head-mounted devices require high electrical power to achieve high brightness, leading to complex heat and electromagnetic interference management, which increases weight and size, and existing waveguides have low coupling efficiency and brightness throughput.

Innovation Solution

The use of a coherent fiber bundle (CFB) to remotely couple a bright image source to a waveguide and collimating optics, allowing for efficient heat and electromagnetic interference management, and enabling a smaller, lighter, and brighter display by decoupling the image source from the waveguide and collimating optics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high electrical power is used to drive the image source to achieve high brightness, then the display brightness is improved, but the heat management complexity and weight of the display assembly increase

Engineering Contradiction:
Improvedisplay brightnessVSAvoiddisplay assembly weight
Core Design Contradiction:
Illumination intensityVSWeight of moving object

Solution Approach 1:

The system divides the display assembly into separate functional modules: the image source is positioned in a first location, the waveguide in a second location, and they are coupled through a coherent fiber bundle. This segmentation allows the heavy heat management components to be separated from the waveguide, reducing the weight and thermal signature at the display location while maintaining high brightness performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A coherent fiber bundle acts as an intermediary to transmit light from the image source to the waveguide. This mediator enables the decoupling of the high-power image source from the sensitive waveguide, allowing bright image generation without directly heating the waveguide assembly, thus reducing weight and thermal management complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If the image source is coupled directly to the waveguide to achieve high brightness, then the illumination intensity is improved, but the thermal signature and electromagnetic interference increase

Engineering Contradiction:
Improvebrightness throughputVSAvoidthermal signature
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The coherent fiber bundle serves as an optical intermediary that transmits light energy from the image source to the waveguide without direct thermal or electromagnetic coupling. This isolation prevents heat and electromagnetic interference from the high-power image source from affecting the waveguide, reducing the thermal signature while maintaining high brightness throughput.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful thermal and electromagnetic effects are extracted from the waveguide assembly by positioning the image source separately and coupling them only optically through the fiber bundle. This extraction removes the heat management burden from the display location while preserving the brightness performance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If the image source is positioned close to the waveguide to improve coupling efficiency, then the brightness throughput is improved, but the weight distribution and thermal management become problematic

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidthermal management
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The coherent fiber bundle maintains efficient optical coupling between the image source and waveguide while allowing physical separation. This intermediary preserves the coupling efficiency needed for high brightness throughput while enabling the image source to be positioned away from the waveguide, improving thermal management and weight distribution.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Volume of moving object

If a compact display design is used to reduce size, then the volume is reduced, but the heat management and weight distribution become more difficult

Engineering Contradiction:
Improvedisplay package sizeVSAvoidheat management
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The compact display design segments the thermal management functions from the optical path. The coherent fiber bundle enables a compact overall form factor while allowing the image source to be positioned in a location optimized for heat dissipation, separating the compact display volume from the thermal management requirements.

Inventive Principle:
Principle #1Segmentation

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 configuration achieves a high luminance display with improved weight distribution and reduced thermal and electromagnetic signatures, providing a more efficient and compact head-mounted display solution.

Implementation Method 1

a coherent fiber bundle (CFB) that is positioned between and coupled to (i) the waveguide and the collimating optics

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a collimating optics module arranged at a second side of the display apparatus... The light rays emitting from each pixel of the image source are received and collimated into parallel rays

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4647830A1System and method for coherent image bundle fiber in displays
Publication Date: 2025.11.12 THALES DEFENSE & SECURITY INC
  • EP4647830A1 patent drawingFigure 1
  • EP4647830A1 patent drawingFigure 2
  • EP4647830A1 patent drawingFigure 3

AI summary

A display apparatus is provided. The display apparatus includes a waveguide and a collimating optics that are positioned at a first side of the display apparatus and coupled to each other. The display apparatus includes an image source and a collimating optics module arranged at a second side of the display apparatus. The second side of the display apparatus is different from the first side of the display apparatus. The display apparatus includes a coherent fiber bundle (CFB) that is positioned between and coupled to (i) the waveguide and the collimating optics and (ii) the image source and the collimating optics module.