Spatial Light Modulator with Three-Stage Ferroelectric Voltage Control

Solution Overview

Problem

Existing spatial light modulation devices face challenges in applying sufficient voltage to ferroelectric liquid crystals while maintaining a narrow pixel pitch and preventing an increase in pixel area, particularly in holographic displays.

Innovation Solution

A spatial light modulation device with a light modulation portion comprising a pixel array, a first driver, a second driver, and a voltage control portion that supplies three-stage potentials to the transparent electrode, utilizing two transistors and a ferroelectric liquid crystal element to control polarization direction effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the pixel pitch is narrowed to 1 μm, then the viewing angle is improved, but the voltage between the reflective electrode and the transparent electrode becomes insufficient to reverse the polarization direction of the FLC

Engineering Contradiction:

Improvepixel pitchVSAvoidvoltage between electrodes

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The patent changes the parameter of the transparent electrode potential from a fixed value to a dynamically controllable value that can be adjusted in response to the reflective electrode potential. This allows the voltage between the electrodes to be optimized for FLC polarization reversal even at narrow pixel pitches of 1 μm or less.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic control of the transparent electrode potential based on the reflective electrode potential state. The transparent electrode potential is no longer fixed but varies dynamically to maintain sufficient voltage across the FLC layer, enabling effective polarization reversal at reduced pixel pitches.

Inventive Principle:

Principle #15Dynamics

2Area of moving object

If the power potential is lowered to accommodate smaller transistors at narrow pixel pitch, then the transistor size is reduced, but the voltage between the reflective electrode and the transparent electrode becomes insufficient

Engineering Contradiction:

Improvetransistor sizeVSAvoidvoltage between electrodes

Core Design Contradiction:

Area of moving objectVSStrength

Solution Approach 1:

The patent changes the parameter of the transparent electrode potential from a fixed value to a dynamically controllable value that can be adjusted in response to the reflective electrode potential. This allows the voltage between the electrodes to be optimized for FLC polarization reversal even at narrow pixel pitches of 1 μm or less.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic control of the transparent electrode potential based on the reflective electrode potential state. The transparent electrode potential is no longer fixed but varies dynamically to maintain sufficient voltage across the FLC layer, enabling effective polarization reversal at reduced pixel pitches.

Inventive Principle:

Principle #15Dynamics

3Area of moving object

If a single transistor is used to control the reflective electrode potential, then the pixel area is reduced, but the driving current for FLC polarization reversal becomes insufficient

Engineering Contradiction:

Improvepixel areaVSAvoiddriving current

Core Design Contradiction:

Area of moving objectVSPower

Solution Approach 1:

The patent introduces the transparent electrode as an intermediary element that can be dynamically controlled to provide the necessary driving voltage and current for FLC polarization reversal. This intermediary control mechanism enables sufficient power delivery without requiring a complex multi-transistor pixel circuit.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution allows for applying sufficient voltage to the liquid crystal while suppressing the increase in pixel area, enabling efficient modulation of light and maintaining high frame rates.

Implementation Method 1

a voltage between the reflective electrode and the transparent electrode is applied to the liquid crystal layer formed of the FLC. When the applied voltage reaches a driving voltage of the FLC, a polarization direction of the FLC can be reversed.

Methodology Applied

Scientific EffectFerroelectric liquid crystal polarization reversal: Liquid Crystals

Data Source

PatentUS20250218411A1Spatial light modulation device

Publication Date: 2025.07.03 LG DISPLAY CO LTD

AI summary

A spatial light modulation device includes: a light modulation portion including a plurality of pixels; a first driver supplying a first potential to the light modulation portion; a second driver supplying a second potential to the light modulation portion; and a voltage control portion supplying a third potential controlled in three stages to the light modulation portion, wherein the pixel includes: a first transistor whose conduction state is controlled by the first potential applied to its gate terminal; a second transistor whose conduction state is controlled by the second potential applied to its gate terminal when the conduction state of the first transistor is on; and a liquid crystal element in which a ferroelectric liquid crystal is interposed between a first electrode whose potential is set according to the conduction state of the second transistor, and a second electrode supplied with the third potential and facing the first electrode.