Transparent LCD Panel Grating Light Management

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Solution Overview

Problem

Conventional liquid crystal displays used in transparent applications suffer from low transparency due to the presence of polarizing plates, which lead to significant absorption of ambient light, reducing their transmittance.

Innovation Solution

A transparent liquid crystal display panel is designed with a first and second substrate, a liquid crystal layer, a first grating layer, and electrode layers, where voltages applied to the electrodes form liquid crystal prisms that enable light to be reflected and returned, eliminating the need for polarizing plates by using a grating structure to manage light transmission and reflection, thereby enhancing transmittance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If polarizing plates are used in liquid crystal displays, then light transmission can be controlled for display function, but transparency is significantly reduced due to light absorption

Engineering Contradiction:

Improvelight transmission controlVSAvoidlight absorption

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The patent removes polarizing plates from the liquid crystal display structure and replaces them with a grating layer that uses diffraction and total reflection to achieve display function without light absorption, thereby extracting the harmful component (polarizing plates) while maintaining the useful function (light transmission control)

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the optical mechanism of polarizing plates with a structural optical mechanism using grating layers and total reflection at the substrate interface, replacing a material-based solution with a geometry-based solution that achieves the same display function without energy loss

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of energy

If a grating layer is added to eliminate polarizing plates, then transparency is improved, but device complexity increases

Engineering Contradiction:

Improvelight transmittanceVSAvoidstructure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The grating layer serves multiple functions simultaneously: it diffracts light to create display patterns, guides light through the liquid crystal layer, and works with the substrate interface to achieve total reflection, thereby consolidating multiple optical functions into a single component that reduces overall device complexity despite the initial addition

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration significantly improves the transmittance of ambient light, allowing for a higher proportion of light to pass through the display panel without the need for polarizers, resulting in increased transparency and improved display performance.

Implementation Method 1

the liquid crystal layer is configured to form a plurality of liquid crystal prisms arranged in an array in the case that voltages are applied to the plurality of first electrodes and the second electrode layer respectively, to enable light emitted from the plurality of liquid crystal prisms to return to the plurality of liquid crystal prisms after being reflected by the second substrate

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

the light emitted from the plurality of liquid crystal prisms returns to the plurality of liquid crystal prisms again after being total reflected by the second substrate

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

a first grating layer between the liquid crystal layer and the first substrate, where the first grating layer includes a plurality of first gratings arranged in an array

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS11137642B2Transparent liquid crystal display panel, method of driving the same, and transparent liquid crystal display including the same

Publication Date: 2021.10.05 BEIJING BOE TECH DEV CO LTD

AI summary

A transparent liquid crystal display panel is provided, including a first substrate and a second substrate oppositely to each other, where the first substrate is configured to enable light incident therein to be transmitted through a reflection; a liquid crystal layer between the first substrate and the second substrate; a first grating layer between the liquid crystal layer and the first substrate, where the first grating layer includes a plurality of first gratings arranged in an array; a first electrode layer between the first grating layer and the liquid crystal layer, where the first electrode layer includes a plurality of first electrodes arranged in an array; and a second electrode layer between the liquid crystal layer and the second substrate; an orthographic projection of each of the first gratings onto the first substrate at least partially covers an area between orthographic projections of two adjacent first electrodes onto the first substrate; where the liquid crystal layer is configured to form a plurality of liquid crystal prisms arranged in an array in the case that voltages are applied to the plurality of first electrodes and the second electrode layer respectively, to enable light emitted from the plurality of liquid crystal prisms to return to the plurality of liquid crystal prisms after being reflected by the second substrate.