Dual-Sided Transmissive LCD With Optical Shutter Light Leakage Control

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Solution Overview

Problem

Conventional liquid crystal display (LCD) devices require separate external light sources and struggle to display images on both sides effectively, leading to issues with light leakage affecting image clarity and increased power consumption.

Innovation Solution

A display device featuring a transmissive liquid crystal panel with backlight units on both sides, accompanied by an optical shutter to control light leakage, allowing for dual-sided image display and reduced power consumption using external light sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If backlight units are installed on both sides of the transmissive liquid crystal panel to enable dual-sided display, then image display capability on both sides is improved, but light leakage affecting the other screen occurs

Engineering Contradiction:

Improvedual-sided display capabilityVSAvoidlight leakage interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

An optical shutter is introduced as an intermediary component between the backlight units and the liquid crystal panel. The shutter selectively blocks light from reaching the panel when not in use, preventing light leakage to the other side while allowing light passage during active display. This mediator resolves the contradiction by controlling light transmission based on operational state.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical shutter is made dynamically controllable, transitioning between open and closed states based on display requirements. When one side needs to display, the corresponding shutter opens; when not in use, it closes to block light. This dynamic adjustment enables dual-sided display capability while preventing light leakage interference between sides.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If conventional LCD devices use external light sources, then power consumption is reduced, but image display quality and clarity deteriorate due to insufficient light control

Engineering Contradiction:

Improvepower consumptionVSAvoidimage display quality

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The optical shutter acts as a mediator that enables effective use of external light sources by controlling when and how light reaches the display panel. During daytime, external light can illuminate the panel; during nighttime or when display is needed, the shutter controls light passage. This allows power-saving external light usage while maintaining reliable image quality through controlled illumination.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system employs periodic control of the optical shutter in conjunction with external light sources, alternating between using external light (daytime/power-saving mode) and backlight units (nighttime/display mode). This periodic action enables power consumption reduction during appropriate periods while maintaining image display quality when needed.

Inventive Principle:

Principle #19Periodic action

3Device complexity

If a single transmissive liquid crystal panel is used for both sides, then manufacturing complexity is reduced, but light leakage between sides increases

Engineering Contradiction:

Improvepanel structure complexityVSAvoidlight leakage

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Optical shutters are positioned between the backlight units and the single transmissive liquid crystal panel, acting as intermediaries that prevent light from leaking to the other side. The shutters block light when the panel is not being viewed from a particular side, enabling the use of a single panel structure while preventing light leakage interference.

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

Enables simultaneous display on both sides of the panel with consistent image quality and resolution, reduces power consumption by utilizing external light, and prevents light leakage interference using the optical shutter, which can also function as a camera flash or auxiliary light.

Implementation Method 1

an optical shutter outside at least one of the first and second backlight units to selectively block light leaking to the outside

Methodology Applied

Scientific EffectLight blocking: Absorption (EM radiation)

Implementation Method 2

a transmissive liquid crystal panel; a first backlight unit on a rear side of the transmissive liquid crystal panel; a second backlight unit on a front side of the transmissive liquid crystal panel

Methodology Applied

Scientific EffectLight transmission: Refraction

Data Source

PatentEP1938145B1Display device and mobile terminal having the same

Publication Date: 2016.03.16 LG DISPLAY CO LTD

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Figure 5(a)~6(b)

AI summary

Provided are a display device and a mobile terminal having the same. The display device comprises a transmissive liquid crystal panel, a first backlight unit on a rear side of the transmissive liquid crystal panel, a second backlight unit on a front side of the transmissive liquid crystal panel, and an optical shutter outside at least one of the first and second backlight units.