Controllable Diffusion in Multiscopic Displays for Wider Viewing Zones

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Solution Overview

Problem

Existing autostereoscopic displays face challenges in maintaining stereoscopic effects when viewers move outside the narrow viewing zone due to the use of collimated backlights, leading to loss of brightness and image degradation at extreme angles.

Innovation Solution

A display system employing a collimated backlight and controllable light diffuser that dynamically expands the viewing zone through horizontal diffusion based on user location, using a processor to adjust the diffuser to ensure accurate image presentation even when viewers are outside the typical viewing zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a collimated backlight unit is used to increase display brightness, then brightness is improved, but the viewing zone becomes narrow and extreme viewing angles result in loss of stereoscopic effect

Engineering Contradiction:
Improvedisplay brightnessVSAvoidviewing zone coverage
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The controllable light diffuser is divided into multiple independently controllable regions corresponding to different backlight unit regions. Each region can be selectively activated to diffuse light in specific directions, allowing the system to expand the viewing zone while maintaining brightness by segmenting the diffusion function across multiple zones rather than using a single uniform diffuser.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The controllable light diffuser enables dynamic adjustment of light diffusion based on viewer position. The processor detects viewer location and selectively activates specific diffuser regions to expand the viewing zone in real-time, transforming the static narrow viewing cone into a dynamically adaptable viewing area that maintains stereoscopic effect across extreme angles.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiscopic optical elements are used to achieve wide viewing zone, then viewing zone is improved, but brightness is reduced when using collimated backlight

Engineering Contradiction:
Improveviewing zone coverageVSAvoiddisplay brightness
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The controllable light diffuser acts as an intermediary element positioned between the collimated backlight unit and the multiscopic optical elements. It selectively diffuses light before it reaches the multiscopic elements, ensuring that sufficient light reaches extreme viewing angles while maintaining the directional control needed for brightness efficiency. This intermediary function resolves the conflict between wide viewing zone and brightness by mediating the light path.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Illumination intensity

If collimated light rays are directed in a narrow cone shape to increase brightness, then brightness is improved, but light rays do not reach extreme viewing angles resulting in image degradation

Engineering Contradiction:
Improvedisplay brightnessVSAvoidstereoscopic effect consistency
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

Different regions of the controllable light diffuser provide different local diffusion qualities. Regions corresponding to central viewing angles have minimal diffusion to maintain brightness, while regions corresponding to extreme viewing angles have enhanced diffusion capability to ensure light reaches those angles. This local quality variation allows the system to maintain high brightness in the center while ensuring reliable stereoscopic effect across all viewing angles.

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

The system provides high-quality, accurate virtual images with stereoscopic effects by expanding the viewing zone, ensuring clear image presentation and maintaining stereoscopic perception even when viewers are positioned outside the conventional viewing area.

Implementation Method 1

selectively activate a corresponding first portion and a corresponding second portion of the at least one controllable light diffuser to horizontally diffuse the first set of collimated light rays and the second set of collimated light rays

Methodology Applied
Scientific EffectLight diffusion: Diffusion

Data Source

PatentEP4633134A1Multiscopic display with collimated backlight and controllable light diffuser
Publication Date: 2025.10.15 DISTANCE TECHNOLOGIES OY
  • EP4633134A1 patent drawingFigure 1A~1B
  • EP4633134A1 patent drawingFigure 2A~2B
  • EP4633134A1 patent drawingFigure 2C~2D

AI summary

Information indicative of a relative location of a first eye (112a, 206a, 208a, 220a, 226a) and of a second eye (112b, 206b, 208b, 220b, 226b) of an individual one of user(s) is obtained. A light field image is generated or retrieved. The light field image is displayed via a liquid crystal display device (102) for presenting virtual object(s). All the aforementioned steps are repeated for a given time period. During the given time period, it is detected when the first eye and/or the second eye lies outside a current viewing zone of a display system (100, 202). When it happens, a given first region of a backlight unit (BLU) (104, 216, 300) is determined to emit a first set of collimated light rays for presenting the virtual object(s) to the first eye, and a given second region of the BLU is determined to emit a second set of collimated light rays for presenting the virtual object(s) to the second eye. A corresponding first portion and a corresponding second portion of controllable light diffuser(s) (106, 204, 306) are selectively activated to horizontally diffuse the first set and the second set, whilst directing towards the first eye and the second eye, respectively.