High-Resolution Display Device Using Photolithography Patterning
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Solution Overview
Problem
Current methods for manufacturing high-resolution display devices face challenges in achieving high aperture ratios and display quality due to limitations in precision and accuracy, particularly when using metal masks, which result in low yield and reduced resolution.
Innovation Solution
A method involving fine patterning of EL layers using photolithography without a shadow mask, combined with a light-blocking layer to protect the EL layer from ultraviolet light, allows for the formation of high-resolution display devices with separate EL layers for each color, enhancing contrast and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metal masks are used for patterning EL layers, then manufacturing process is simple, but manufacturing precision and resolution are limited
Solution Approach 1:
The patent replaces the mechanical shadow mask system with a photolithography system. Instead of using physical masks that limit resolution, the invention uses light-based patterning with photoresist layers to achieve high-resolution patterns (5000 ppi) without the mechanical constraints of metal masks.
Solution Approach 2:
The patent introduces photoresist layers as intermediary materials between the patterning light and the EL layers. These photoresist layers enable precise pattern transfer through chemical reactions when exposed to light, achieving high manufacturing precision without direct mechanical contact that would limit resolution.
2Manufacturing precision
If photolithography without shadow mask is used, then resolution increases to 5000 ppi, but process complexity increases
Solution Approach 1:
The patent segments the patterning process into multiple distinct steps: applying photoresist, exposing to light, developing, and etching. This segmentation allows each step to be optimized independently and performed by standard semiconductor manufacturing equipment, making the complex high-resolution process manageable and manufacturable.
Solution Approach 2:
The patent applies photoresist layers and forms patterns before depositing the EL layers. This preliminary patterning action ensures that the EL layers are deposited only in the desired pixel regions, achieving high resolution without requiring complex in-situ patterning during EL layer formation.
3Ease of manufacture
If ultraviolet light is used for light exposure, then photosensitive resin can be cured, but EL layer may be damaged by ultraviolet light
Solution Approach 1:
The patent performs the light exposure and curing of the photosensitive resin before depositing the EL layers. This preliminary action ensures that the ultraviolet light is applied when the EL layers are not yet present, avoiding any damage to the EL materials while still achieving complete curing of the resin for structural integrity.
Solution Approach 2:
The patent separates the ultraviolet light exposure step from the EL layer deposition step into distinct sequential operations. This segmentation allows the photosensitive resin to be cured with full ultraviolet exposure before the EL layers are introduced, eliminating the conflict between resin curing requirements and EL layer protection needs.
4Reliability
If light-blocking layer is added to protect EL layer, then EL layer integrity is maintained, but device structure becomes more complex
Solution Approach 1:
The patent provides preliminary protection by performing all ultraviolet light exposure operations before EL layer deposition. This eliminates the need for light-blocking layers between the resin and EL layers, as the timing of operations inherently protects the EL layers from ultraviolet damage.
Solution Approach 2:
The patent extracts the potential harm (ultraviolet light exposure) from the sequence of operations by removing it before EL layer deposition. Instead of adding protective layers to block harm, the invention removes the harmful action itself from the process sequence, simplifying the overall structure.
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 the production of display devices with high resolution, high aperture ratios, and improved display quality by preventing leakage currents and maintaining EL layer integrity, achieving resolutions up to 5000 ppi without the need for pseudo-improvements like PenTile patterns.
Implementation Method 1
a resin layer covering end portions of the second layer and the fourth layer is formed by application of a photosensitive resin, light exposure, and development
Implementation Method 2
The second layer and the fourth layer contain a material which reflects or absorbs the first light
Data Source
AI summary
To provide a method of manufacturing a display device capable of high resolution. To provide a display device having both high display quality and high resolution. A first EL layer, a first layer, and a second layer are formed over a first pixel electrode; a second EL layer, a third layer, and a fourth layer are formed over the second pixel electrode; a resin layer covering an end portion of the second layer and an end portion of the fourth layer is formed by applying a photosensitive resin, exposing the photosensitive resin to light, and developing the photosensitive resin; a top surface of the first EL layer and a top surface of the second EL layer are exposed by etching parts of the first layer, the second layer, the third layer, and the fourth layer which are not covered with the resin layer; and a common electrode covering the first EL layer, the second EL layer, and the resin layer are formed. First light containing ultraviolet light is used for the light exposure, and the second layer and the fourth layer contain a material which reflects or absorbs the first light.