Pixel Electrode Contact via Ink-Jet Color Filter
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Solution Overview
Problem
Conventional methods for fabricating liquid crystal display (LCD) pixel structures with a color filter on a thin film transistor array (COA) require numerous processes, leading to decreased aperture ratio and increased manufacturing costs, particularly due to the need for a light shielding layer at contact holes which obstructs ink flow during ink-jet printing.
Innovation Solution
A method that omits forming the light shielding layer at contact holes, using a passivation layer and ink-jet printing to create a color filter pattern within defined areas, allowing for increased aperture ratio and simplified fabrication by reducing the number of process steps and materials needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a light shielding layer is formed at contact holes to prevent ink flow during ink-jet printing, then manufacturing precision is improved, but aperture ratio decreases
Solution Approach 1:
The patent removes the light shielding layer from the contact hole area, extracting only the necessary light shielding function from the problematic location. The light shielding layer is retained in surrounding areas to prevent ink flow, but eliminated where it would block the aperture, thus resolving the contradiction between manufacturing precision and aperture ratio.
Solution Approach 2:
The patent applies different structural configurations to different regions: in the contact hole area, no light shielding layer is formed to maximize aperture, while in surrounding areas, the light shielding layer is maintained to control ink flow during printing. This localized differentiation resolves the contradiction by optimizing each region for its specific function.
2Manufacturing precision
If multiple fabrication processes are used for COA structure, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple fabrication steps into a more integrated process. By forming the color filter layer using ink-jet printing directly on the TFT array substrate and selectively forming the light shielding layer only in specific regions, the patent merges what would otherwise be separate photolithography and etching steps into a simplified sequence, reducing overall device complexity while maintaining alignment precision.
Solution Approach 2:
The patent performs preliminary formation of the color filter layer pattern before finalizing the contact hole structure. The ink-jet printed color filter layer serves as a preliminary structure that guides subsequent processing, allowing contact holes to be formed through the color filter layer to expose the underlying active device, thereby reducing the need for additional alignment processes.
3Manufacturing precision
If a light shielding layer is formed to define unit area, then manufacturing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent replaces traditional mechanical photolithography processes with ink-jet printing technology for forming the color filter layer. This substitution eliminates the need for complex photomask alignment and chemical development processes, achieving precise color filter pattern definition through digital ink placement while significantly simplifying the fabrication procedure and improving ease of manufacture.
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 enhances the aperture ratio of the pixel structure, simplifies the fabrication process, and reduces manufacturing costs by minimizing the usage of passivation and buffer layers, while ensuring electrical connectivity between the active device and pixel electrode.
Implementation Method 1
an ink-jet printing process is performed to form a color filter pattern within the unit area defined by the light shielding layer
Implementation Method 2
the pixel electrode fills into the contact hole so as to electrically connect with the active device
Data Source
AI summary
A pixel structure including an active device, a capacitor electrode line, a light shielding layer, a color filter pattern and a pixel electrode is provided. The active device and the capacitor electrode line are disposed on a substrate. The light shielding layer is disposed on the substrate, and the dielectric constant of the light shielding layer is less than 6. The light shielding layer defines a unit area on the substrate, and a contact hole is formed in the light shielding layer above the active device. A color filter pattern is disposed in the unit area, wherein the dielectric constant of the color filter pattern is less than 6, and the color filter pattern does not fill into the contact hole. The pixel electrode is disposed on the color filter pattern, in which the pixel electrode fills into the contact hole so as to electrically connect with the active device.