LCD Backlight Segmentation for Interior Mode Power Reduction

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Solution Overview

Problem

Large and high-resolution liquid crystal display devices consume high electric power, especially when only portions of the panel are used to display images, as the backlight unit operates at full capacity regardless of the image area, leading to inefficient power usage.

Innovation Solution

A liquid crystal display device with a backlight unit divided into separately drivable light source blocks, controlled by an image processing circuit and backlight controller to turn on only the necessary light source blocks for moving images and turn off those for still images, reducing power consumption by generating a light source driving control signal based on a movement judgment signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the backlight unit operates at full capacity to display images on the entire LCD panel, then the illumination intensity and image quality are improved, but the electric power consumption increases significantly

Engineering Contradiction:

Improvebacklight illuminationVSAvoidelectric power consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The backlight unit is divided into multiple independently controllable light source blocks (e.g., first through fourth light source blocks corresponding to different regions of the panel). Each block can be selectively activated or deactivated based on the display requirements, allowing the system to provide full illumination when needed while consuming less power when only portions of the panel are in use.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the backlight unit operates at full capacity regardless of image area, then the image quality is maintained, but the electric power efficiency deteriorates when only portions of the panel are used

Engineering Contradiction:

Improveimage qualityVSAvoidpower efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The backlight control system dynamically adjusts which light source blocks are activated based on real-time detection of image content and panel usage patterns. The controller receives video data, determines the active display region, and selectively enables only the necessary light source blocks, thereby maintaining image quality in the active region while minimizing energy consumption across the entire panel.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If the backlight unit is always on in normal driving mode, then the LCD panel can display images anywhere on the panel, but the electric power consumption remains high even in interior mode

Engineering Contradiction:

Improvedisplay flexibilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

Different regions of the backlight unit are independently controlled to match the local display requirements. When images are displayed only in specific portions of the panel (interior mode), only the corresponding light source blocks are activated. This localized control maintains display flexibility while significantly improving power efficiency by avoiding illumination of regions that are not currently in use.

Inventive Principle:

Principle #3Local quality

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 enables the display of images on only portions of the LCD panel with significantly reduced electric power consumption, maximizing efficiency by limiting backlight usage to 10-20% of normal mode power in interior mode, while maintaining image quality.

Implementation Method 1

controlling the light transmittance ratio of the liquid crystal layer using an electric field applied to the liquid crystal layer

Methodology Applied

Scientific EffectElectric field control of liquid crystal molecules: Electro-Optic Effects

Implementation Method 2

the TFT turns on so that a channel is formed between the source electrode and the drain electrode to supply the voltage on the data line (DL) to the pixel electrode

Methodology Applied

Scientific EffectField effect transistor conduction: Conduction (electrical)

Implementation Method 3

The storage capacitor (Cst1) charges the data voltage supplied from the data line (DL) when the TFT turns on to keep the voltage of the liquid crystal cell (Clc) constant

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS8223115B2Liquid crystal display and driving method thereof

Publication Date: 2012.07.17 LG DISPLAY CO LTD

AI summary

The liquid crystal display device includes a plurality of gate lines and a plurality of data lines forming a matrix, a back light unit including a plurality of light source blocks capable of being driven separately, an image processing circuit to generate a movement judgment signal based on a digital video data to be displayed in an interior mode, a backlight controller to generate a light source driving control signal to control portions of the light source blocks corresponding to a moving image and portions of the light source blocks corresponding to a still image, separately, based on the movement judgment signal, and a backlight driving circuit including a plurality of light source drivers to turn on the portions of the light source blocks corresponding to a moving image and to turn off the portions of the light source blocks corresponding to a still image based on the light source driving control signal.