Overhang Layer Pattern Reduces Pixel Gap in Display Devices
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Solution Overview
Problem
The fine metal mask (FMM) method for display device manufacturing is limited in producing high-resolution displays due to a minimum gap of about 20 micrometers between pixel-defining layers, leading to potential dark spots and reduced display quality.
Innovation Solution
A display device structure and manufacturing method that includes a conductive pattern with a specific thickness and overhang layer pattern, using different metals and inorganic materials, which reduces the gap between pixel-defining layers to about 3 micrometers, enhancing pixel density and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the FMM method is used to form pixels by aligning a mask and substrate in a vacuum chamber, then the manufacturing process is simple and straightforward, but the minimum gap between pixel-defining layers is limited to about 20 micrometers, preventing high-resolution display
Solution Approach 1:
The patent transitions from planar pixel-defining layers to three-dimensional structures with overhang layers that extend laterally beyond the conductive pattern. This dimensional change allows the pixel-defining layer to achieve smaller gaps (3 micrometers) by utilizing vertical stacking and lateral overhang geometry rather than relying solely on horizontal spacing in a single plane.
Solution Approach 2:
The patent implements a nested structure where the overhang layer is positioned above and extends beyond the conductive pattern, which itself is above the pixel-defining layer. This nested arrangement of multiple layers (pixel-defining layer → conductive pattern → overhang layer) enables precise spatial control and reduces the effective gap between functional pixel regions while maintaining structural integrity.
2Reliability
If a spacer is located on the substrate to support the mask in the FMM method, then the mask is properly supported during manufacturing, but the stamping phenomenon causes insufficient distance between the spacer and pixel, resulting in dark spots and deteriorated display quality
Solution Approach 1:
The patent removes the traditional spacer component entirely from the manufacturing process. Instead of using a spacer to support the mask during deposition, the invention relies on the self-aligned nature of the vacuum deposition process combined with the geometric configuration of the pixel-defining layer and overhang layer, thereby eliminating the stamping phenomenon and associated display defects.
Solution Approach 2:
The patent implements self-alignment through the geometric relationship between the pixel-defining layer, conductive pattern, and overhang layer. The overhang layer's lateral extension automatically defines the pixel boundaries and spacing without requiring external spacer components, allowing the structure to self-define its geometry and eliminate manufacturing defects related to spacer positioning.
Data Source
AI summary
A display device includes a conductive pattern, an overhang layer pattern, an organic layer, and a second electrode. A width of a top surface of the overhang layer pattern is greater than a width of a top surface of the conductive pattern. The display device disconnects the organic layer by including the overhang layer pattern serving as a tip, and the display device includes a second electrode contacting sidewalls of the conductive pattern to be connected over an entirety of a panel.