Multicolor OLED Display Manufacturing via Shared Emissive Layers
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Solution Overview
Problem
Existing multicolor OLED displays require precise patterning of OLED layers, leading to complex manufacturing processes, increased power consumption due to unequal sensitivity of red, green, and blue pixels, and inefficiencies in aligning shadow masks, which complicates manufacturing and reduces throughput.
Innovation Solution
A method for making a multicolor OLED display with shared light-emitting layers for certain pixels, using color filters to achieve desired colors, reducing the need for precise patterning and alignment, and improving power efficiency by optimizing light emission spectra.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate OLED electroluminescent layers are provided for each pixel to achieve desired colors, then color accuracy is improved, but manufacturing complexity increases due to precise alignment requirements
Solution Approach 1:
The patent extracts the alignment complexity by removing the shadow mask component entirely. Instead of using a shadow mask to define pixel patterns during deposition, the invention deposits OLED layers uniformly across the substrate and uses subsequent photolithographic patterning to define pixel boundaries. This eliminates the precise mechanical alignment between shadow mask and substrate that plagues conventional methods.
Solution Approach 2:
The patent replaces the mechanical shadow mask alignment system with a photolithographic patterning system. Instead of relying on mechanical precision to position shadow masks, the invention uses light-based photolithography to define pixel patterns after uniform layer deposition, substituting a less precision-critical mechanical process with an optical patterning process.
2Illumination intensity
If red and blue pixels emit more light to compensate for lower human eye sensitivity, then color brightness is improved, but power consumption increases
Solution Approach 1:
The patent changes the spectral parameters of the OLED emissive layers to optimize power efficiency. Specifically, it employs yellow-green and red-emitting OLED layers combined with color filters, rather than using traditional red, green, and blue emissive layers. This spectral reconfiguration allows the display to achieve desired color output with lower power consumption by operating in wavelength ranges where the human eye is more sensitive.
Solution Approach 2:
The patent introduces color filters as intermediary components between the OLED emissive layers and the viewer. Instead of relying on the OLED layers to emit all necessary colors directly, the invention uses yellow-green and red OLED layers that excite phosphor-based color filters to produce the full color spectrum, reducing the power required from the OLED layers themselves.
3Manufacturing precision
If shadow masks are used to pattern OLED layers, then manufacturing precision is improved, but manufacturing throughput decreases due to alignment time
Solution Approach 1:
The patent performs preliminary uniform deposition of OLED layers across the entire substrate before any patterning operations. By depositing complete layers first and then using photolithography to define pixel patterns, the invention eliminates the time-consuming alignment step that would otherwise be required to position shadow masks precisely during deposition. This sequence reversal significantly improves manufacturing throughput.
4Manufacturing precision
If laser writing is used to transfer OLED material from donor sheets, then manufacturing precision is improved, but equipment complexity and consumable costs increase
Solution Approach 1:
The patent eliminates the need for expensive, consumable donor substrates by using uniform deposition followed by photolithographic patterning. Instead of transferring material from precious donor sheets using complex laser writing, the invention deposits OLED materials uniformly across inexpensive substrates and defines patterns through photolithography, replacing high-cost consumables with lower-cost materials and processes.
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 simplifies manufacturing, reduces power consumption, and enhances color gamut by allowing for improved light emission spectra alignment, resulting in more efficient and cost-effective production of multicolor OLED displays.
Implementation Method 1
providing a first light-emitting layer over a substrate for the first and second pixels and a providing a second light-emitting layer over the substrate for the third pixel wherein the first and second light-emitting layers produce light having different spectra
Implementation Method 2
forming a first color filter in operative relationship with the first pixel and no color filter corresponding to the second pixel
Data Source
AI summary
A method of making an OLED display having at least first, second, and third differently colored pixels includes providing a first light-emitting layer over a substrate for the first and second pixels and a providing a second light-emitting layer over the substrate for the third pixel wherein the first and second light-emitting layers produce light having different spectra and the light produced by the first light-emitting layer has substantial spectral components corresponding to the light output desired for the first and second pixels, and forming a first color filter in operative relationship with the first pixel and no color filter corresponding to the second pixel.