Shared Light-Emitting Layer OLED Structure for High Productivity
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Solution Overview
Problem
The existing manufacturing processes for light-emitting devices face challenges in achieving high productivity and low power consumption, particularly due to the need for precise alignment of light-emitting layers and the energy loss associated with color filters or color conversion layers in full-color displays.
Innovation Solution
A light-emitting device structure is proposed, where multiple pixels share a common light-emitting layer or optical element, with specific spectral peaks for different colors, allowing for reduced manufacturing steps and lower power consumption by minimizing the use of optical elements for certain pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light-emitting layers for different colors are deposited side by side using a shadow mask, then full-color display is achieved, but alignment accuracy requirements increase and manufacturing yield decreases
Solution Approach 1:
The patent merges the deposition process for different colored light-emitting layers into a single step by forming a multi-layer structure (first light-emitting layer, second light-emitting layer, third light-emitting layer) that can be deposited simultaneously or in sequence without requiring precise alignment of separate shadow masks for each layer. This combining approach eliminates the cumulative alignment errors that would occur with multiple separate deposition steps.
Solution Approach 2:
The patent creates a universal light-emitting structure where the same basic layer configuration (electrode, hole-transport layer, light-emitting layer, electron-transport layer, extraction layer) serves multiple color functions. By varying the material composition within the light-emitting layer while maintaining the same structural framework, the device can produce different colors without requiring separate manufacturing processes for each color, thus reducing alignment requirements.
2Ease of manufacture
If color filters or color conversion layers are used to achieve full-color display, then color reproduction is improved, but energy loss increases and power consumption rises
Solution Approach 1:
The patent extracts and eliminates the need for separate color filters or color conversion layers by directly incorporating color-generating light-emitting layers into the OLED structure. Instead of using a white light source that passes through color filters (which waste energy by blocking unwanted wavelengths), the invention generates different colors directly through electroluminescence in the light-emitting layers, thereby removing the energy-lossy optical elements from the system.
Solution Approach 2:
The patent replaces the optical filtering mechanism (which relies on passive absorption and reflection of light by color filters) with an electroluminescent mechanism that actively generates light of specific colors through electrical excitation. This substitution of the light generation mechanism eliminates the need for energy-wasting optical filtering and directly produces the desired colors with higher efficiency.
3Ease of manufacture
If higher current density is applied to compensate for energy loss in color filters, then color display quality is maintained, but power consumption increases and reliability decreases
Solution Approach 1:
The patent converts the potential harm of high current density operation (which would normally degrade reliability) into a benefit by using low-current-density, direct-color light-emitting layers. Instead of forcing high current through inefficient color filters, the invention uses materials and structures that achieve excellent color display quality at low current densities, thereby improving both reliability and power efficiency simultaneously.
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 approach increases productivity by simplifying the manufacturing process and reduces power consumption by minimizing energy loss through the elimination of optical elements for certain pixels, enhancing color reproducibility and efficiency.
Implementation Method 1
voltage application between electrodes, between which a light-emitting layer is interposed, causes recombination of electrons and holes injected from the electrodes, which brings a light-emitting substance (an organic compound) into an excited state, and the return from the excited state to the ground state is accompanied by light emission
Implementation Method 2
a first optical element which extracts light from the first light-emitting element
Data Source
AI summary
A novel light-emitting device with small power consumption, which can be formed with high productivity, is provided. The light-emitting device includes a first pixel, a second pixel, and a third pixel. The first pixel includes a first light-emitting element and a first optical element, the second pixel includes a second light-emitting element and a second optical element, and the third pixel includes a third light-emitting element. A first light-emitting layer or a second light-emitting layer is shared among the first to third light-emitting elements. Furthermore, the first light-emitting layer includes a first light-emitting material having a spectrum peak in the range of higher than or equal to 540 nm and lower than or equal to 580 nm, and the second light-emitting layer includes a second light-emitting material having a spectrum peak in the range of higher than or equal to 420 nm and lower than or equal to 480 nm.