Backlight Chip Layout With Dummy Patterns for Luminance Uniformity

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Solution Overview

Problem

The luminance difference among light-emitting chips in display apparatuses is caused by resistance variations in the driving and ground voltage lines, leading to inconsistent lighting performance.

Innovation Solution

A display apparatus design featuring a light-source module with a driving voltage line, ground voltage line, and light-emitting chips separated by insulating layers and dummy patterns, connected via emission and address connecting lines, with reflective and scattering layers to enhance light distribution and reduce resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the driving voltage line and ground voltage line are extended to connect all light-emitting chips, then the electrical connection is improved, but the resistance increases causing luminance difference

Engineering Contradiction:
Improveelectrical connectionVSAvoidluminance difference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The voltage lines are divided into multiple segments with intermediate connection points. Instead of using single long continuous lines, the patent introduces intermediate voltage lines that connect to multiple light-emitting chips at different positions, effectively segmenting the electrical path to reduce cumulative resistance and voltage drop.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a one-dimensional linear arrangement of voltage lines to a two-dimensional network structure. Multiple voltage lines are arranged in parallel and connected to different rows or columns of light-emitting chips, creating a grid-like distribution that reduces the effective resistance by providing multiple parallel current paths.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If dummy patterns are added to reduce resistance, then the electrical connection is improved, but the device complexity increases

Engineering Contradiction:
Improveelectrical connectionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The dummy patterns serve multiple functions: they act as electrical connection paths to reduce resistance, serve as structural support elements, and can be integrated with existing manufacturing processes. By making these elements multi-functional, the patent reduces the need for separate components, thereby limiting the increase in overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The dummy patterns are merged with the existing voltage line structure and insulating layer system. Instead of adding completely separate components, the patent integrates the dummy patterns into the existing layered structure, combining their function with the electrical connection system to minimize additional complexity.

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 design minimizes resistance variations, maintains consistent luminance across light-emitting chips, and enhances lighting efficiency without lowering process efficiency.

Implementation Method 1

the optical sheet includes a reflective plate on the upper insulating layer, the reflective plate comprising a reflective pattern having a conductive material

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a scattering layer that covers the reflecting pattern

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP4206807B1Display apparatus having a back-light unit having light-emitting chips
Publication Date: 2025.08.06 LG DISPLAY CO LTD
  • EP4206807B1 patent drawingFigure 1
  • EP4206807B1 patent drawingFigure 2
  • EP4206807B1 patent drawingFigure 3~5

AI summary

A back-light unit including light-emitting chips and a display apparatus are disclosed. The back-light unit includes a driving voltage line on a substrate, and a ground voltage line spaced apart from the driving voltage line. The light-emitting chips are on a lower insulating layer covering the driving voltage line and the ground voltage line. A driving chip electrically connected to the ground voltage line may be on the substrate. Each of the light-emitting chips may be electrically connected between the driving voltage line and the driving chip by emission connecting lines. A driving dummy pattern and/or a ground dummy pattern is between the light-emitting chips and the emission connecting lines. The driving dummy pattern is electrically connected to the driving voltage line, and the ground dummy pattern is electrically connected to the ground voltage line. Thus, a luminance difference of the light-emitting chips may be prevented or at least reduced.