Display Device EL Layer Patterning Without Shadow Masks
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Solution Overview
Problem
Current display devices face challenges in achieving high resolution, low power consumption, high contrast, and high display quality while maintaining a novel manufacturing structure and method with high yield, particularly in achieving precise patterning of light-emitting elements without using shadow masks which often result in deviations and defects.
Innovation Solution
The display device employs a structure with multiple conductive and insulating layers, including a unique method of forming EL layers separately without a shadow mask, using a resist mask for sacrificial layers to reduce the margin for pixel positions, allowing for closer spacing of EL layers and increased aperture ratio, and integrating insulating layers to improve coverage and prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If shadow masks are used for patterning light-emitting elements, then manufacturing process is simplified, but positioning deviations and defects occur reducing manufacturing precision
Solution Approach 1:
The patent removes the shadow mask from the patterning process entirely. Instead of using a shadow mask to define pixel patterns, the invention forms the light-emitting layer directly over insulating layers that have predefined openings, eliminating the shadow mask and its associated positioning deviations and defects.
Solution Approach 2:
The insulating layers are formed with openings in predetermined positions before the light-emitting layer is deposited. This preliminary structuring of the insulating layers guides the subsequent formation of light-emitting elements without requiring a shadow mask, ensuring precise pixel positioning from the outset.
2Manufacturing precision
If larger margins are provided for pixel positions, then positioning accuracy is improved, but aperture ratio decreases reducing display quality
Solution Approach 1:
The patent applies different functional qualities to different regions: the insulating layers provide structural definition and insulation in non-light-emitting regions, while the light-emitting layers provide light emission in designated pixel regions. This localized functional differentiation allows precise pixel positioning without requiring large uniform margins, maximizing aperture ratio.
3Reliability
If multiple insulating layers are integrated, then coverage and short circuit prevention are improved, but device complexity increases
Solution Approach 1:
The insulating layers serve multiple functions simultaneously: they provide electrical insulation between conductive layers, define pixel patterns through their openings, support the light-emitting layers, and prevent short circuits. This multi-functionality reduces the need for separate dedicated layers, managing complexity while enhancing reliability.
4Area of stationary object
If EL layers are formed closer together, then aperture ratio increases improving display quality, but risk of short circuits increases
Solution Approach 1:
The insulating layers are positioned between adjacent light-emitting layers and conductive elements, serving as intermediary barriers that prevent direct contact and potential short circuits. This intermediary insulation allows the light-emitting layers to be formed closer together, increasing aperture ratio while maintaining reliability.
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 fabrication of high-resolution display devices with high aperture ratios, reduced power consumption, and improved display quality by minimizing non-light-emitting regions and enhancing the conductivity of common electrodes, while simplifying the manufacturing process and reducing costs.
Implementation Method 1
By applying voltage to this element, light emission can be obtained from the light-emitting organic compound
Data Source
AI summary
A display device with high display quality is provided. A highly reliable display device is provided. A display device with low power consumption is provided. A display device that can easily achieve higher resolution is provided. A display device with both high display quality and high resolution is provided. A display device with high contrast is provided. The display device includes a first conductive layer, a first insulating layer over the first conductive layer, a second conductive layer including a first region over the first insulating layer and a second region in an opening provided in the first insulating layer, a second insulating layer over the first insulating layer, a third insulating layer over the second region, an EL layer including a third region over the first region, a fourth region over the second insulating layer, and a fifth region over the third insulating layer, and a third conductive layer over the EL layer. The opening is provided in the first insulating layer so as to reach a top surface of the first conductive layer. A top surface of the first region, a top surface of the second insulating layer, and a top surface of the third insulating layer are substantially level with each other.