Backlight Driver Vertical Scan Horizontal Drive Local Dimming

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Solution Overview

Problem

Conventional display devices using local dimming techniques often suffer from a 'waterfall phenomenon' where horizontal line images with high or low luminance appear or move, due to sequential driving of light source rows, leading to reduced image quality and increased power consumption.

Innovation Solution

A display device with a backlight unit comprising light source rows and blocks, where the backlight driver performs a vertical direction scan operation to select light source rows and a horizontal direction sequential driving operation to drive light source blocks, optimizing the timing and direction of light emission to reduce luminance interference and prevent the waterfall phenomenon.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If light source rows are sequentially driven to perform local dimming, then power consumption is reduced and contrast ratio is increased, but a waterfall phenomenon occurs where horizontal line images with high or low luminance appear or move

Engineering Contradiction:

Improvebacklight power consumptionVSAvoidwaterfall phenomenon

Core Design Contradiction:

Use of energy by stationary objectVSObject-affected harmful factors

Solution Approach 1:

The backlight unit is divided into multiple light source rows, each independently controllable. This segmentation allows sequential driving of rows to reduce overall power consumption while maintaining local dimming capability. Each row can be activated only when needed, preventing the waterfall phenomenon by controlling the temporal activation of segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The backlight driver sequentially activates light source rows in a periodic manner rather than continuously. By controlling the timing and duration of each row's activation, the system reduces power consumption while preventing the waterfall phenomenon through proper timing control that avoids luminance interference between adjacent rows.

Inventive Principle:

Principle #19Periodic action

2Adaptability or versatility

If light source rows are sequentially driven, then local dimming control is achieved, but luminance interference between adjacent rows causes image quality degradation

Engineering Contradiction:

Improvelocal dimming controlVSAvoidluminance interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The backlight driver pre-controls the activation timing of each light source row before potential luminance interference can occur. By anticipating and preventing interference through proper timing sequencing, the system maintains local dimming adaptability while avoiding image quality degradation from luminance interference between adjacent rows.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system monitors the luminance output of each light source row and adjusts the activation timing and duration accordingly. This feedback mechanism ensures that local dimming control is maintained while preventing luminance interference by dynamically adjusting operation parameters based on actual performance and interference conditions.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11289034B2Display device performing local dimming

Publication Date: 2022.03.29 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a backlight unit including light source rows, each of the light source rows including light source blocks, a display panel configured to display an image by transmitting light emitted by the backlight unit, a panel driver configured to drive the display panel, and a backlight driver configured to drive the backlight unit. The backlight driver is configured to perform a vertical direction scan operation that sequentially select the light source rows and a horizontal direction sequential driving operation that sequentially drives the light source blocks included in a selected light source row of the light source rows.