Organic EL Display Layered Structure for Color Mixing Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current display apparatus technologies face challenges in achieving high resolution, low power consumption, and reduced manufacturing costs, particularly due to issues with color mixing, energy loss, and increased complexity in manufacturing processes related to the use of white CF, separate-patterning, and color conversion layer techniques in organic EL displays.
Innovation Solution
A display apparatus with a layered structure comprising a common red light-emitting layer and separate blue and green light-emitting layers, where the layers are positioned to minimize energy transfer and maximize light emission efficiency, eliminating the need for color filters and allowing for independent luminescent color production in each subpixel without color mixing or shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a white color filter technique is used to form full-color organic EL display apparatus, then each subpixel can emit white light by layering red, green, and blue light-emitting layers, but the manufacturing process becomes more complex and requires higher resolution vapor deposition masks
Solution Approach 1:
The patent divides the display into separate red, green, and blue subpixels, each with its own light-emitting layer formed by independent vapor deposition. This segmentation allows each color to be deposited separately without requiring high-resolution masks to pattern all colors simultaneously, thereby reducing manufacturing precision requirements while maintaining ease of manufacture
Solution Approach 2:
The patent applies different light-emitting layer configurations to different subpixels: red subpixels have only red light-emitting layers, green subpixels have only green light-emitting layers, and blue subpixels have only blue light-emitting layers. This local differentiation eliminates the need for complex white light emission and color filtering, simplifying the manufacturing process and reducing mask resolution requirements
2Measurement precision
If separate-patterning vapor deposition is performed with vapor deposition masks for individual colors, then subpixels can be selectively made to emit light of their respective colors, but color mixing may occur between adjacent subpixels
Solution Approach 1:
The patent extracts the color definition function from the vapor deposition mask and relocates it to the light-emitting layer material selection and bank structure. By using banks to physically separate adjacent subpixels and selecting luminescent materials with distinct emission spectra, the patent prevents color mixing without relying on high-resolution masks, thereby maintaining color emission accuracy while eliminating the harmful effect of color mixing
Solution Approach 2:
The patent introduces banks as intermediary structures between adjacent subpixels. These banks act as physical barriers that prevent the lateral spread of deposited material and light, thereby preventing color mixing between subpixels while allowing each subpixel to maintain its intended color emission characteristics
3Adaptability or versatility
If color filters are used in each subpixel to achieve full-color display, then the display apparatus can show different colors, but energy loss increases and power consumption rises
Solution Approach 1:
The patent converts the previously harmful effect of requiring color filters into a benefit by using banks with openings that naturally define subpixel regions. The banks serve as both structural elements and optical elements, allowing light to pass through openings while blocking lateral light spread, thereby achieving full-color display without the energy loss associated with color filters
Solution Approach 2:
The patent enables each subpixel to self-generate its specific color through the use of luminescent materials with distinct emission spectra in red, green, and blue subpixels respectively. This self-service approach eliminates the need for external color filters that would otherwise be required to achieve full-color display, thereby reducing energy loss while maintaining color display capability
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 enables high-efficiency luminescent color production in each subpixel, reduces power consumption, and lowers manufacturing costs by eliminating the need for color filters and simplifying the vapor deposition process, while maintaining high resolution and preventing color mixing or shifting.
Implementation Method 1
The EL element emits light by the use of the light-releasing phenomenon observed when excitons generated by the recombination of the electrons and the holes having been injected into the light-emitting layer are deactivated
Implementation Method 2
The light-emitting layer in the EL element is formed mainly by the use of a vapor deposition technique such as the vacuum vapor deposition technique
Implementation Method 3
Each green subpixel includes a green color conversion layer configured to convert the blue light to the green light
Data Source
AI summary
Provided is a display apparatus where: a red light-emitting layer is formed as a layer that is common to a first subpixel, a second subpixel, and a third subpixel; a blue light-emitting layer is formed as a layer that is common to the first subpixel and the second subpixel; and the green light-emitting layer is formed only in the second subpixel.