Switchable Optical Element for Secure Display Viewing Angle Control

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Solution Overview

Problem

Existing screen technologies face challenges in efficiently switching between narrow and wide viewing angles without significant brightness loss or increased power consumption, particularly when applying to self-luminous displays, and are often costly to produce and maintain.

Innovation Solution

The use of controllable layers in lamellae that can be transparent or self-luminous, allowing for switching between modes by superimposing light from the screen with light from the lamellae to block side views, while maintaining high luminance and minimizing power consumption, with passive light stream means that are transparent when not in use to reduce haze.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional films based on micro-slats are used to improve optical data protection, then viewing angle control is improved, but manual handling and removal is required and light loss is very high

Engineering Contradiction:
Improveviewing angle controlVSAvoidlight loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent replaces manual mechanical handling of micro-slat films with an automated electro-optical system. Liquid crystal layers are electrically controlled to switch between transparent and scattering states, eliminating the need for manual film application and removal while maintaining viewing angle control functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the optical parameters of the liquid crystal layers by applying electrical voltage. When voltage is applied, the liquid crystals transition from a transparent state to a scattering state, dynamically controlling light transmission and viewing angles without physical film manipulation.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If medium-polarization rotation with built-in electrical switching is used, then switching between public and private mode is achieved, but image brightness is strongly reduced

Engineering Contradiction:
Improvemode switching capabilityVSAvoidimage brightness
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent introduces an intermediate scattering layer composed of liquid crystal particles suspended in a scattering medium. This intermediary layer selectively scatters light at oblique angles while allowing direct viewing to remain bright, mediating between privacy protection and image luminance requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a second LC screen with collimated backlight is used, then viewing angle control is improved, but technical effort and costs are high and brightness is reduced

Engineering Contradiction:
Improveviewing angle controlVSAvoidtechnical effort
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the viewing angle control function from the main LCD screen structure and implements it separately through front-side liquid crystal layers and scattering elements. This separation allows independent optimization of the display and privacy control functions, reducing overall system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

4Adaptability or versatility

If chromonic layers are used for switching between free and restricted view, then viewing angle control is achieved, but light loss is very high and implementation is expensive

Engineering Contradiction:
Improveviewing mode switchingVSAvoidimplementation cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent uses conventional liquid crystal materials whose optical properties can be changed by electrical parameter adjustment rather than requiring specialized chromonic materials. This approach maintains manufacturing simplicity and reduces costs while achieving the same viewing angle control functionality.

Inventive Principle:
Principle #35Parameter changes

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 approach allows for secure data entry with minimal power consumption and negligible brightness reduction, applicable to self-luminous displays, and is cost-effective for series implementation, enabling secure information representation with wide viewing angles when needed.

Implementation Method 1

Each slat (4) has controllable layers (2) which can be transparent or even (bright) self-luminous

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

those slats (4) which do not contain any of said controllable layers (2) contain passive light stream means (6) which scatter light

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP3350650B1Method and arrangement for the secure display of information
Publication Date: 2021.03.10 SIOPTICA GMBH
  • EP3350650B1 patent drawingFigure 1~2
  • EP3350650B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a screen (1) in at least two states of operation: B1 as a free viewing mode and B2 as a restricted viewing mode, comprising the following steps: arranging a switchable optical element (3), which ensures switching between the at least two states of operation B1 and B2, in the viewing direction of an observer (5) directly in front of a screen (1), displaying image content on the screen (1), wherein the optical element (3) contains a plurality of ribs (4), and wherein the optical effect of the ribs (4) can be changed between transparent (B1) and luminous (B2) in that at least each twentieth rib (4) contains controllable layers (2) which can be switched to transparent or brightly self-luminous. A corresponding arrangement is also described.