Organic EL Light-Emitting Device Thermal Conductor Design
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Solution Overview
Problem
Organic EL elements in light-emitting devices are prone to breakdown due to Joule heat and short circuits caused by dust or uneven electrodes, leading to reliability and productivity issues, especially in bottom-emission devices where heat dissipation is inefficient.
Innovation Solution
A light-emitting device design featuring a substrate with an organic EL element, a counter substrate with projection structures, and a thermal conductor or inert gas to enhance heat dissipation, where the inert gas relieves pressure and prevents foreign substance-induced short circuits by filling the space between the substrate and counter substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermal conductor is provided in the sealed space to conduct heat from the organic EL element to the counter substrate, then heat dissipation is improved, but a short circuit may occur because dust or unevenness on the cathode is crashed by the thermal conductor during sealing
Solution Approach 1:
The patent introduces an inert liquid as an intermediary substance between the thermal conductor and the organic EL element. This inert liquid acts as a cushioning layer that prevents direct contact between the thermal conductor and the cathode, thereby eliminating the short circuit risk caused by dust or unevenness on the cathode surface while still allowing efficient heat conduction from the organic EL element to the counter substrate through the inert liquid medium.
2Temperature
If pressure is applied to spread the thermal conductor uniformly during sealing, then thermal conduction efficiency is improved, but dust or unevenness on the cathode is crashed causing short circuits
Solution Approach 1:
The inert liquid serves as a mediator that allows pressure to be applied for uniform thermal conductor distribution without transmitting the crushing force directly to the cathode. The inert liquid absorbs and distributes the pressure uniformly, enabling the thermal conductor to spread evenly while the cathode remains protected from damage by dust or unevenness.
3Use of energy by moving object
If the layer containing light-emitting organic compound becomes thinner to improve device performance, then light emission efficiency is improved, but the layer breaks down more easily due to Joule heat
Solution Approach 1:
The patent replaces the traditional solid thermal conductor with an inert liquid thermal conductor that can flow and adapt to the thin organic EL layer structure. This fluid-based thermal management system provides superior thermal contact with the thin light-emitting layer, efficiently conducting Joule heat away from the organic compound layer without requiring physical contact that could damage the thin structure, thereby maintaining high light emission efficiency while preventing thermal breakdown.
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 design improves the reliability and productivity of light-emitting devices by efficiently dissipating heat and reducing the likelihood of short circuits, thereby protecting the organic EL element from damage and maintaining device performance.
Implementation Method 1
a thermal conductor being provided in the sealed space and conducting heat of the organic EL element to the counter substrate
Implementation Method 2
the inert gas relieves pressure and prevents foreign substance-induced short circuits by filling the space between the substrate and counter substrate
Implementation Method 3
Joule heat is caused depending on current flowing through the element
Implementation Method 4
the organic EL element emits light by causing current to flow therethrough
Data Source
AI summary
A light-emitting device with high reliability is provided. A light-emitting device includes a substrate 101, an organic EL element 110 formed over the substrate, a counter substrate 102 which is disposed so as to face the substrate, a plurality of projection structures 102a which are formed on the counter substrate and face the organic EL element, and a thermal conductor 135a of a liquid, a solid, or the like, which is disposed between the substrate and the counter substrate. The plurality of projection structures and the organic EL element are each in contact with the thermal conductor.