Edge Type Backlight Unit Local Dimming via Segmented Light Guide Plate

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Solution Overview

Problem

Edge type backlight units face limitations in performing local dimming and scan driving, which are advantages of direct type backlight units, while also aiming to provide benefits in weight, power consumption, and image quality.

Innovation Solution

A backlight unit with a light guide plate featuring a lens-shaped light path changing pattern on its top surface and reflective patterns on its bottom surface, divided into dot blocks, allows for efficient local dimming and scan driving by selectively applying current to LEDs, improving light distribution and contrast ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If edge type backlight unit is used, then weight and power consumption are reduced, but local dimming and scan driving capabilities are limited

Engineering Contradiction:

Improvepower consumptionVSAvoidlocal dimming and scan driving capability

Core Design Contradiction:

Use of energy by stationary objectVSAdaptability or versatility

Solution Approach 1:

The light guide plate is divided into multiple regions with different reflective properties. Specifically, a first light guide plate portion has a reflective pattern while a second light guide plate portion has a light path changing pattern, enabling independent control of light distribution in different areas for local dimming and scan driving operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the light guide plate are赋予 different optical characteristics. The first portion contains reflective patterns to redirect light in specific directions, while the second portion contains light path changing patterns to guide light along different paths, allowing localized control of light emission for dimming and scanning functions.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If direct type backlight unit is used, then local dimming and scan driving are enabled, but more LEDs are required and power consumption increases

Engineering Contradiction:

Improvelocal dimming and scan driving capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The edge type backlight unit is designed to perform multiple functions including local dimming, scan driving, and uniform illumination. By incorporating both reflective patterns and light path changing patterns in the light guide plate, the single edge-type structure can achieve capabilities traditionally associated with direct type backlight units.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The light guide plate acts as an intermediary that redistributes light from the edge-mounted LED array. Through strategic placement of reflective and light path changing patterns, it enables localized light control and scanning effects without requiring additional LEDs throughout the display area.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If reflective patterns are added to light guide plate, then light distribution control is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvelight distribution controlVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The reflective patterns and light path changing patterns are integrated into a single light guide plate structure. This unified design allows both optical functions to be achieved through one manufacturing process rather than requiring separate components, reducing overall manufacturing complexity while maintaining precise light distribution control.

Inventive Principle:

Principle #5Merging (Combining)

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 enhances the edge type backlight unit's ability to perform local dimming and scan driving, reducing power consumption and improving image quality while maintaining advantages in weight and profile thickness.

Implementation Method 1

The light from the light source in the edge type backlight unit is refracted by the light guide plate to proceed to the liquid crystal panel.

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

a plurality of reflective patterns on a bottom surface of the body

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS9507076B2Backlight unit and liquid crystal display device including the same

Publication Date: 2016.11.29 SAMSUNG DISPLAY CO LTD

AI summary

A backlight unit and a display device having the same are discussed. According to an embodiment, the backlight unit includes a light source configured to generate light; and a light guide plate configured to distribute the light received from the light source, the light guide plate including: at least one body, each of the at least one body divided into a plurality of blocks, and a plurality of reflective patterns formed on a bottom surface of the body, wherein the plurality of reflective patterns are selectively provided at some of the plurality of blocks.