Color Conversion Layer Patterning via Thermal Cycle Nano Imprint
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Solution Overview
Problem
Conventional methods for patterning color conversion layers in organic EL displays face limitations in achieving high definition and large area coverage due to the use of metal masks, which restrict pixel resolution and yield, and struggle with thermal expansion and alignment issues.
Innovation Solution
A thermal cycle nano imprint technique is employed to pattern the color conversion layer, where a mold with a fine pattern is heated and pressed onto the layer within the glass transition temperature range of the material, allowing for precise pattern transfer without the need for metal masks, and oxygen plasma processing is used to refine the pattern, all conducted in an inline vacuum process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metal mask is used to pattern the color conversion layer, then the patterning process can be performed, but the pixel resolution is limited to 150-200 ppi and the definition of finer mask patterns cannot be achieved
Solution Approach 1:
The invention removes the metal mask from the patterning process entirely. Instead of using a metal mask to define pixel patterns, the color conversion layer itself is directly patterned through thermal cycle nano imprinting, extracting the patterning function from the mask and transferring it to the organic layer through thermal deformation.
Solution Approach 2:
The invention replaces the mechanical metal mask system with a thermal field-based patterning system. By applying cyclic thermal fields to the color conversion layer, the material undergoes controlled deformation and self-patterning, substituting mechanical mask constraints with thermal field control to achieve higher resolution.
2Strength
If a metal mask with thickness around 50 microns is used, then sufficient strength is provided, but the size of potential openings in the mask pattern is limited and higher definition patterns cannot be obtained
Solution Approach 1:
The invention extracts the patterning function from the metal mask structure entirely. The color conversion layer is patterned through direct thermal cycle nano imprinting without requiring a metal mask, thereby eliminating the trade-off between mask thickness for strength and pattern definition capability.
Solution Approach 2:
The invention changes the physical state and properties of the color conversion layer through temperature control during patterning. By heating the organic layer above its glass transition temperature, the material becomes deformable and can be precisely patterned through thermal cycle nano imprinting, achieving high definition without mechanical mask constraints.
3Manufacturing precision
If a metal mask is used for patterning, then the color conversion layer can be patterned, but alignment problems occur due to differences in thermal expansion coefficients between the metal mask and substrate
Solution Approach 1:
The invention removes the metal mask component from the system, eliminating the thermal expansion coefficient mismatch issue entirely. The patterning is achieved through direct thermal cycle nano imprinting of the color conversion layer, removing the interface between dissimilar materials that causes alignment problems.
Solution Approach 2:
The invention uses homogeneous organic material (color conversion layer) for patterning throughout the entire process. By using the same material system for both the layer being patterned and the patterning mechanism (thermal cycle nano imprinting), thermal expansion mismatches and alignment issues between different materials are avoided.
4Manufacturing precision
If the color conversion layer is formed as a continuous film, then the layer can be deposited uniformly, but it becomes impossible to emit light resolved into each primary color without separate fine patterns
Solution Approach 1:
The invention performs preliminary deposition of a continuous color conversion layer film before patterning. This continuous film is then subsequently patterned through thermal cycle nano imprinting, allowing the deposition process to remain simple while achieving fine patterns in a second step.
Solution Approach 2:
The invention segments the manufacturing process into two distinct steps: first, deposition of a continuous color conversion layer; second, patterning of this layer through thermal cycle nano imprinting. This segmentation allows each step to be optimized independently, maintaining ease of deposition while achieving fine pattern definition.
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 method enables the creation of organic EL displays with sub-pixel widths and inter-pixel spacings less than 50 μm and 5 μm, respectively, and allows for larger display dimensions, overcoming the limitations of conventional metal mask techniques by achieving high definition and increased yield.
Implementation Method 1
a mold formed with a fine pattern is heated and brought into contact with the color conversion layer and pressed thereto to deform the color conversion layer to thereby transfer the fine pattern of the mold onto the color conversion layer, wherein the mold is heated to a temperature within a range of the glass transition temperature of the color conversion layer (Tg)±25° C.
Implementation Method 2
oxygen plasma processing is used to refine the pattern
Data Source
AI summary
A method of patterning a color conversion layer for an organic EL device is provided together with a method of manufacturing a multiple color emitting organic EL display using the patterning method. The patterning method includes forming the color conversion layer on a base having an organic layer and patterning the color conversion layer by carrying out a thermal cycle nano imprint technique.