Light-Emitting Device Self-Recovery from Short Circuits via Oxide Layer
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Solution Overview
Problem
Existing light-emitting elements face issues with short circuits between electrodes, leading to defects and increased resistance, which can cause deterioration and affect the characteristics of the element, and existing solutions like filling defects with insulating materials can inadvertently increase resistance in non-defect regions.
Innovation Solution
Incorporating oxide layers in contact with electrodes and an electron-injection layer, where oxygen reacts with electrode materials to form insulators at short-circuited parts, and using alkaline earth metals to adsorb moisture and prevent further deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a defect in an EL layer is filled with an insulating material using electrodeposition method, then a short circuit between electrodes is prevented, but a region other than the defect is also covered with insulating material which increases resistance and deteriorates characteristics
Solution Approach 1:
The patent applies local quality by making the oxide layer's oxygen availability spatially non-uniform. The oxide layer is positioned adjacent to the EL layer such that oxygen is readily available at defect locations (where short circuits occur) but limited in other regions. This ensures insulating material forms only where needed (at defects) while avoiding unnecessary insulating coverage that would increase resistance in functional areas.
Solution Approach 2:
The oxide layer acts as an intermediary between the insulating material source and the EL layer defects. Instead of directly applying insulating material throughout the device, the oxide layer mediates the process by providing oxygen that reacts with metal atoms to form insulating oxides only at locations where metal atoms are present (i.e., at defect sites), thereby preventing short circuits without adversely affecting other regions.
2Reliability
If insulating material is applied to fill defects, then short circuit is prevented, but resistance of the light-emitting element is increased
Solution Approach 1:
The oxide layer enables localized insulating material formation by providing oxygen only where metal atoms are present at defect sites. This spatial selectivity ensures that insulating material is formed exclusively where needed for short circuit prevention, while maintaining low resistance in the remaining functional areas of the light-emitting element.
Solution Approach 2:
The patent converts the potentially harmful effect of metal atoms (which cause short circuits) into a beneficial insulating oxide layer. By providing oxygen from the oxide layer, metal atoms that would otherwise create conductive paths are transformed into insulating oxide material, thereby preventing short circuits while controlling overall resistance.
3Reliability
If oxide layer is provided to enable self-recovery, then short circuit prevention is achieved, but device structure is made more complex
Solution Approach 1:
The oxide layer serves multiple functions simultaneously: it acts as an oxygen source for insulating material formation, provides a barrier layer, and enables the self-recovery function. By consolidating these functions into a single layer, the patent achieves short circuit prevention and self-recovery capabilities without proportionally increasing device complexity.
Solution Approach 2:
The oxide layer enables self-service by allowing the light-emitting element to automatically repair its own defects through the self-recovery function. When a short circuit occurs, oxygen from the oxide layer reacts with metal atoms to form insulating material, and the applied voltage automatically drives this repair process without external intervention, thereby achieving reliability improvement with minimal structural complexity.
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
The light-emitting elements can self-recover from short circuits without adversely affecting their characteristics, improving yield and performance by maintaining the element's functionality and preventing moisture-induced deterioration.
Implementation Method 1
oxygen in the oxide layer and an electrode material in a short-circuited part are reacted with each other and the electrode material in the short-circuited part can be an insulator
Implementation Method 2
due to heat generated when a short circuit is caused between a pair of electrodes
Implementation Method 3
oxygen in the oxide layer and the alkaline earth metal in the electron-injection layer are reacted with each other to form an oxide of the alkaline earth metal
Implementation Method 4
the oxide of the alkaline earth metal can adsorb the moisture that enters the short-circuited part
Data Source
AI summary
A light-emitting device and a lighting device each including a light-emitting element which can recover from a short circuit between a pair of electrodes by itself without adversely affecting the characteristics of the element is provided. An oxide layer is provided so as to be in contact with an electrode of the light-emitting element, whereby, due to heat generated when a short circuit is caused between a pair of electrodes, oxygen in the oxide layer and an electrode material in a short-circuited part are reacted with each other and the electrode material in the short-circuited part can be an insulator. Further, by providing an oxide layer in contact with an electron-injection layer containing an alkaline earth metal, an oxide of the alkaline earth metal can be formed, whereby moisture that enters the insulator formed by an insulation phenomenon in the short-circuited part can be adsorbed and removed.