Bistable Luminescent Display Unit for Low Power Static Images

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Solution Overview

Problem

Electroluminescent display devices like LEDs and LCDs consume high power when displaying static images, which does not meet user requirements for lower power consumption, especially in applications like billboards and electronic price tags.

Innovation Solution

A display unit with a functional layer made of luminescent materials having electrical bistable characteristics, comprising an electroluminescent layer and an auxiliary layer, which can switch between high and low conductivity states to emit or not emit light, reducing power consumption by maintaining the high conductivity state even after power is removed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If electroluminescent display devices (LEDs and LCDs) are used to display static images, then the display function is achieved, but the power consumption is very large

Engineering Contradiction:

Improvepower consumptionVSAvoiddisplay stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies dynamics by making the conductivity state changeable through voltage control. The functional layer can dynamically switch between low conductivity (non-emitting) and high conductivity (emitting) states, allowing the display to maintain images without continuous power supply while still being controllable when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical parameter (conductivity) of the functional layer by applying different voltages. By controlling the voltage applied to the functional layer, the device can switch between emitting and non-emitting states, enabling low power consumption for static displays while maintaining display functionality.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If continuous power supply is provided to maintain display, then the display stability is ensured, but the power consumption increases

Engineering Contradiction:

Improvedisplay stabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by setting the functional layer in a high conductivity state before power removal. This preliminary high conductivity state ensures that the display maintains stability for a period after power is removed, achieving both display stability and low power consumption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies self-service by allowing the functional layer to maintain its high conductivity state and continue emitting light without external power supply. The material's inherent properties enable it to sustain the conducting state temporarily, reducing the need for continuous external energy input.

Inventive Principle:

Principle #25Self-service

3Use of energy by moving object

If the functional layer switches between conductivity states, then the power consumption is reduced, but the refresh rate may be affected

Engineering Contradiction:

Improvepower consumptionVSAvoidrefresh rate

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The patent applies periodic action by using controlled voltage pulses to switch the functional layer between states during refresh operations. During normal display, power is removed for low consumption; during refresh, periodic voltage application restores the display state, achieving both low power consumption and adequate refresh rates.

Inventive Principle:

Principle #19Periodic action

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 display unit achieves reduced power consumption and supports full-color display without continuous power supply, meeting user requirements for lower power usage and faster refresh rates, while avoiding defects like mottling.

Implementation Method 1

a functional layer disposed between the first electrode and the second electrode, and the functional layer includes a luminescent material having electrical bistable characteristics

Methodology Applied

Scientific EffectElectrical bistability:

Implementation Method 2

the functional layer includes an electroluminescent layer and an auxiliary layer

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS11489129B2Display unit, display substrate and driving method thereof, and display device

Publication Date: 2022.11.01 BEIJING BOE OPTOELECTRONCIS TECH CO LTD

AI summary

A display unit, a display substrate, a driving method of the display substrate and a display device are provided. The display unit includes a first electrode, a second electrode disposed above the first electrode, a functional layer disposed between the first electrode and the second electrode, and the functional layer includes a luminescent material with electrical bistable characteristics. The display unit is provided with the functional layer of the luminescent material with the electrical bistable characteristics, so that the display unit can emit light when being in a high conductivity state and still keep emitting light after being de-energized, and does not emit light when being in a low conductivity state, thereby realizing display and non-display of the display unit.