Optical Path Control Member Using Pulse Voltage for Privacy Switching

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Solution Overview

Problem

Existing optical path control members face issues with deteriorated driving characteristics and dispersibility of particles when switching between light transmitting and blocking modes.

Innovation Solution

An optical path control member that applies a pulse voltage to uniformly disperse light conversion particles, preventing concentration in specific regions and improving driving speed and characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a negative voltage is applied to disperse particles in the dispersion liquid to switch the pattern part to a light blocking part, then the viewing angle control is achieved, but the particles may not be dispersed well and the dispersibility is deteriorated

Engineering Contradiction:
Improveshielding characteristicsVSAvoiddriving characteristics
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies a pulse voltage with a specific waveform (including a rising edge, plateau, and falling edge) to disperse particles. The periodic nature of the voltage application with distinct phases enables effective particle dispersion while maintaining driving characteristics, resolving the contradiction between shielding reliability and ease of operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the voltage parameters (applying a negative voltage with specific magnitude and duration) to achieve proper particle dispersion. By optimizing the voltage parameters, the patent simultaneously achieves good shielding characteristics and maintains ease of operation, resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If particles are dispersed and aggregated by applying voltage to switch between light transmitting and blocking parts, then the viewing angle control is achieved, but the driving speed is reduced and dispersibility is deteriorated

Engineering Contradiction:
Improveviewing angle controlVSAvoiddriving speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The pulse voltage waveform with its structured time profile (rising edge, plateau, falling edge) enables faster particle response. The periodic application of voltage with optimized timing accelerates the dispersion and aggregation process, improving driving speed while maintaining reliable viewing angle control.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

By optimizing the voltage parameters (magnitude, duration, waveform shape), the patent accelerates particle movement and dispersion. This parameter optimization achieves both fast driving speed and reliable viewing angle control, resolving the contradiction between these two features.

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

Enhances the driving speed and characteristics by uniformly dispersing light conversion particles, ensuring smooth transitions between public and privacy modes.

Implementation Method 1

by applying a pulse voltage capable of uniformly dispersing the light conversion particles with a constant magnitude, time, and period

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 2

the light conversion particles can be uniformly dispersed in a dispersion liquid in the privacy mode

Methodology Applied
Scientific EffectLight absorption and scattering: Absorption (EM radiation)

Implementation Method 3

switching a pattern part to a light transmitting part and a light blocking part by filling the inside of the pattern part with particles that may move when a voltage is applied

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentEP4137867B1Optical path control member and display device comprising same
Publication Date: 2025.11.26 LG INNOTEK CO LTD
  • EP4137867B1 patent drawingFigure 1~2
  • EP4137867B1 patent drawingFigure 3~4
  • EP4137867B1 patent drawingFigure 5~6

AI summary

An optical path control member according to an embodiment comprises: a first substrate; a first electrode arranged on the first substrate; a second substrate arranged on the first substrate; a second electrode arranged beneath the second substrate; and a light conversion unit arranged between the first electrode and the second electrode, wherein the light conversion unit comprises a partition part and an accommodation part alternately arranged, the accommodation part includes a dispersion liquid and light conversion particles dispersed in the dispersion liquid, the accommodation part operates in a public mode or a privacy mode according to whether a voltage is applied, a first voltage is applied when changing from the privacy mode to the public mode, a second voltage and a third voltage are applied when changing from the public mode to the privacy mode, and the second voltage and/or the third voltage include a pulse voltage.