Display Panel Light Extraction Without Polarizing Plates

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Solution Overview

Problem

Traditional liquid crystal displays have low optical efficiency and high power consumption due to the need for polarizing plates, which only allow a portion of light rays with changed polarization states to be emitted, resulting in low brightness and high power consumption.

Innovation Solution

A display panel structure that includes a light extracting layer, a light transmitting layer with liquid crystal gratings in intersecting planes, and a filter layer, allowing light rays to be diverged and emitted in different polarization directions without polarizing plates, achieving bright and dark states by controlling liquid crystal molecule orientations with electrode groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If polarizing plates are used in traditional liquid crystal displays, then polarization control is achieved, but optical efficiency decreases and power consumption increases

Engineering Contradiction:
Improvepower consumptionVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The patent removes the polarizing plates from the liquid crystal display structure. By extracting these components, the system eliminates the source of energy loss while maintaining polarization control functionality through alternative means (liquid crystal molecule orientation control), thereby reducing power consumption and improving optical efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/polarization-based control system with an electric field-based control system. Instead of using polarizing plates to control light polarization, the invention uses electric fields to control liquid crystal molecule orientation, which in turn controls light transmission. This substitution eliminates the need for polarizing plates and reduces energy consumption.

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

2Loss of energy

If polarizing plates are used to control light polarization, then display function is achieved, but optical efficiency decreases

Engineering Contradiction:
Improveoptical efficiencyVSAvoiddisplay brightness
Core Design Contradiction:
Loss of energyVSIllumination intensity

Solution Approach 1:

By removing the polarizing plates from the system, the patent eliminates the optical loss associated with polarization filtering. This extraction allows more light to pass through the display structure, thereby improving optical efficiency and increasing display brightness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the control parameter from polarization state (requiring polarizing plates) to liquid crystal molecule orientation (controlled by electric fields). This parameter change enables better light transmission control without the optical losses of traditional polarizing plates, improving both optical efficiency and brightness.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If light shielding regions are used to achieve dark state, then contrast is improved, but light transmission is blocked

Engineering Contradiction:
Improvedisplay contrastVSAvoidlight transmission
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent employs dynamic control of liquid crystal molecule orientation through electric fields to achieve both bright and dark states. In the dark state, electric fields align molecules to block light; in the bright state, molecules are oriented to transmit light. This dynamic control provides excellent contrast without requiring static light shielding regions that would permanently block light.

Inventive Principle:
Principle #15Dynamics

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 solution enhances optical efficiency and transparency by allowing all light rays to be emitted, reducing the need for polarizing plates and improving display brightness and power efficiency.

Implementation Method 1

a light transmitting layer located between the filter layer and the light extracting layer and a liquid crystal layer configured to provide sub-pixel regions at a bright state with liquid crystal gratings distributed in a first plane and a second plane so that the light rays provided by the light extracting element are diverged in the first plane and the second plane

Methodology Applied
Scientific EffectLiquid crystal grating: Liquid Crystals

Implementation Method 2

the first electrode group is configured to form a liquid crystal grating located in the first plane in the liquid crystal layer by an electric field generated by the first electrode group

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 3

to provide sub-pixel regions at a dark state with liquid crystal molecules of the liquid crystal layer whose long axis orientations are toward the light shielding region in the sub-pixel regions at the dark state

Methodology Applied
Scientific EffectLiquid crystal orientation: Liquid Crystals

Implementation Method 4

a light extracting layer, comprising a light extracting element in each of the sub-pixel regions, the light extracting element being configured to provide light rays propagating toward the light shielding region of the sub-pixel region where the light extracting element is located

Methodology Applied
Scientific EffectLight extraction: Light

Data Source

PatentEP3859441B1Display panel, method for driving same, and display device
Publication Date: 2024.03.06 BOE TECHNOLOGY GROUP CO LTD
  • EP3859441B1 patent drawingFigure 1~2
  • EP3859441B1 patent drawingFigure 3~4
  • EP3859441B1 patent drawingFigure 5~6

AI summary

The present disclosure provides a display panel, a driving method thereof, and a display device. The display panel includes: a filter layer including a light shielding region and a light transmitting region in each sub-pixel region, the light transmitting region in each of the sub-pixel regions surrounding the light shielding region; a light extracting layer including a light extracting element in each of the sub-pixel regions, the light extracting element being configured to provide light rays propagating toward the light shielding region of the sub-pixel region where the light extracting element is; and a light transmitting layer located between the filter layer and the light extracting layer and configured to provide sub-pixel regions at a bright state gratings distributed in a first plane and a second plane, so that the light rays provided by the light extracting element are diverged in the first plane and the second plane, the first plane and the second plane being intersected with each other and both perpendicular to a light emitting surface of the display panel.