Light-emitting Element Shield Walls for Parasitic Capacitance Equalization

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Solution Overview

Problem

Organic electroluminescence display devices experience uneven luminance due to parasitic capacitance differences between odd and even rows, leading to streaky spots and reduced image resolution.

Innovation Solution

A light-emitting element configuration with a driving circuit and shield walls to minimize the influence of adjacent pixels, including a driving transistor, image signal writing transistor, and capacitor unit, with shield walls extending in the first direction between light-emitting elements to equalize parasitic capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If driving circuits are disposed upside down alternately in odd and even rows to reduce area, then area of driving circuits is reduced, but parasitic capacitance between adjacent pixels differs between odd and even rows causing uneven luminance

Engineering Contradiction:

Improvearea of driving circuitsVSAvoiduniformity of parasitic capacitance

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent introduces asymmetry by adding shield walls specifically to even rows (or odd rows, depending on implementation) while maintaining the alternating upside-down layout. This asymmetric modification compensates for the parasitic capacitance imbalance caused by the symmetric alternating layout, equalizing the total parasitic capacitance across all rows without sacrificing area reduction benefits

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the physical structure by adding shield walls that extend in the first direction between light-emitting elements. This structural parameter change increases parasitic capacitance in specific rows (even or odd) to match the capacitance level of other rows, thereby equalizing the overall parasitic capacitance across all rows and eliminating luminance unevenness

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If shield walls are added to equalize parasitic capacitance, then uniformity of luminance is improved, but device complexity increases

Engineering Contradiction:

Improveuniformity of luminanceVSAvoidcomplexity of light-emitting element structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by adding shield walls only to specific rows (even rows or odd rows) rather than uniformly to all rows. This localized modification addresses the parasitic capacitance imbalance in a targeted manner, improving luminance uniformity while minimizing the increase in overall device complexity by avoiding unnecessary shield walls in all rows

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11183117B2Light-emitting element and display device

Publication Date: 2021.11.23 SONY GROUP CORP

AI summary

A light-emitting device comprising an emitting unit including at least two emitting elements, a driving unit configured to control the emitting unit, and a capacitor unit formed over the driving unit. A shield layer may be located between the two emitting elements. In one example, the capacitor unit is formed at a level higher than a level of the driving unit, and a shield layer that is located between the two emitting elements is formed at a level that is higher than the level of the driving unit and equal to or lower than the level of the capacitor unit.