Direct-Type Backlight LCD Layout for Blue-Light Edge Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing direct-type backlight liquid crystal display devices suffer from uneven light emission and low color purity due to the deflection of blue light at the edges, leading to a blue phenomenon and reduced display effectiveness.

Innovation Solution

The device incorporates a design where blue sub-pixels are partially blocked by a black matrix at the edges, with narrowed effective display areas, and employs a reflective structure to redirect blue light, along with a frame sealant to minimize light loss, enhancing light efficiency and uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If blue sub-pixels are arranged at the outermost edge of the color film substrate, then the display coverage is maximized, but blue light deflection occurs at the edges causing color purity degradation and a blue phenomenon

Engineering Contradiction:
Improvedisplay coverageVSAvoidblue light deflection and color purity degradation
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful blue light deflection at the edges into a beneficial effect by intentionally positioning blue sub-pixels at the outermost edge. The black matrix strategically blocks excessive blue light while allowing sufficient blue light to pass through, transforming the potential color purity problem into a design feature that maximizes display coverage without significant color degradation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies different treatment to different regions of the display. The black matrix is positioned to selectively block blue light at the edge regions where blue sub-pixels are located, while leaving the central regions unaffected. This local quality approach ensures that blue light management is optimized specifically at the edges without compromising the overall display performance

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If the effective display area of blue sub-pixels at the edge is reduced by black matrix blocking, then color purity is improved, but light utilization efficiency decreases

Engineering Contradiction:
Improvecolor purityVSAvoidlight utilization efficiency
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The patent applies partial blocking of blue light using the black matrix at the edges rather than complete blocking. This partial action approach maintains sufficient blue light transmission to preserve color purity while avoiding excessive light loss. The black matrix blocks only the excessive blue light that causes color degradation, leaving the necessary blue light for normal display function

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent optimizes the parameters of the black matrix including its width, position, and optical properties to achieve the right balance between color purity and light utilization. By carefully adjusting these parameters, the black matrix blocks sufficient blue light to prevent color degradation while maintaining adequate light transmission for display effectiveness

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If multiple lamp tubes are used in direct-type backlight to increase light source intensity, then brightness is improved, but light distribution uniformity deteriorates

Engineering Contradiction:
ImprovebrightnessVSAvoidlight distribution uniformity
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent introduces a reflective plate as an intermediary component between the multiple lamp tubes and the liquid crystal display panel. This reflective plate redirects and redistributes the light from multiple lamp tubes, ensuring that light from different sources is evenly distributed across the display area, thus maintaining uniformity while benefiting from the increased brightness of multiple lamp tubes

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

This configuration improves light utilization and color saturation by reducing the effective display area of blue sub-pixels at the edges, ensuring uniform light emission and enhanced display quality.

Implementation Method 1

a light homogenizing element, the light emitting element is disposed on the bottom plate, light emitted by the light emitting element is projected at a light incident side of the liquid crystal display panel after being adjusted by the light homogenizing element

Methodology Applied
Scientific EffectLight reflection and redistribution: Reflection

Implementation Method 2

the set of sub pixels which are located on a main surface of the color film substrate at one edge along the first direction are partially covered by a black matrix

Methodology Applied
Scientific EffectLight absorption and blocking: Absorption (EM radiation)

Implementation Method 3

a liquid crystal layer sandwiched between the array substrate and the color film substrate

Methodology Applied
Scientific EffectLiquid crystal optical modulation: Liquid Crystals

Data Source

PatentEP4116764B1Liquid crystal display device having a direct-type backlight
Publication Date: 2025.11.05 BOE TECHNOLOGY GROUP CO LTD
  • EP4116764B1 patent drawingFigure 1~3
  • EP4116764B1 patent drawingFigure 4~5
  • EP4116764B1 patent drawingFigure 6~8

AI summary

At least one embodiment of the disclosure provides a direct-type backlight liquid crystal display device, and the direct-type backlight liquid crystal display device includes a frame (101), including a main frame (101a)and a bottom plate (101b); a liquid crystal display panel (102), arranged on a top surface of the main frame (101a) and parallel to the bottom plate (101b), in which the liquid crystal display panel (102) includes an array substrate (1021), a color film substrate (1022), a liquid crystal layer and a frame sealant (1024), a pixel unit (1025) on the color film substrate (1022) includes a sub pixel (1025a), and the sub pixel (1025a) located on a side of the color film substrate (1022) along a first direction parallel to the color film substrate (1022) is partially blocked and covered by a black matrix, a backlight unit (103), including a light emitting element (103a) and a light homogenizing element (103b); and a display control unit (104), disposed at a lateral end surface of the liquid crystal display panel (102) and electrically connected with the liquid crystal display panel (102) at the lateral end surface of the liquid crystal display panel (102), the blue sub pixels (1025b) provided by the embodiments of the present disclosure are arranged at the outermost edge of the pixel region, so that the unmixed blue light directly passes through the blue sub pixels (1025b) to improve light efficiency and color saturation, thereby improving the utilization rate of white light emitted by a light emitting diode and improving the uniformity of light emission.