Microcavity Display Pixel Structure for High Color Purity
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Solution Overview
Problem
Current display devices face challenges in achieving high color purity, high resolution, low power consumption, and high yield, particularly in large-sized displays, due to limitations in manufacturing methods such as the side-by-side method and color filter method, which result in decreased yield and increased costs.
Innovation Solution
A display device structure incorporating a light-emitting layer with a microcavity structure for subpixels emitting specific colors and a separate layer for white light emission, combined with a semi-transmissive layer that enhances light extraction efficiency and color purity, while maintaining low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the side-by-side method is used to manufacture full-color display devices, then light color purity is improved, but manufacturing precision and yield deteriorate due to the need for high alignment accuracy of metal mask opening portions
Solution Approach 1:
The invention divides the light-emitting layer into multiple regions, each emitting a different color (red, green, blue, white), eliminating the need for color filters and metal mask alignment. This segmentation approach allows each region to be independently formed without requiring high precision alignment between different color layers.
Solution Approach 2:
The invention transitions from a planar approach requiring precise mask alignment to a vertical stacking approach where different color regions are formed in different spatial locations on the substrate. This dimensional change allows colors to be differentiated by position rather than by precise overlay of mask patterns.
2Illumination intensity
If the side-by-side method is used for high-resolution display devices, then light color purity is improved, but productivity deteriorates due to extremely high alignment accuracy requirements
Solution Approach 1:
The light-emitting layer is segmented into multiple regions emitting different colors, eliminating the need for high-precision mask alignment processes. This segmentation allows for simpler, more rapid manufacturing while maintaining color purity through spatial separation of color-emitting regions.
Solution Approach 2:
The invention extracts and eliminates the metal mask alignment step from the manufacturing process by forming color regions directly in the light-emitting layer through selective evaporation or deposition in different spatial locations, thereby improving productivity.
3Productivity
If the color filter method is used to manufacture large-sized display devices, then productivity is improved, but light color purity deteriorates due to inclusion of unwanted wavelengths
Solution Approach 1:
The invention segments the light-emitting layer into regions that emit specific colors directly, replacing the color filter approach. This eliminates the need for filters that transmit unwanted wavelengths while maintaining high productivity through a simplified manufacturing process.
Solution Approach 2:
Instead of using color filters to remove unwanted wavelengths (which reduces light efficiency), the invention converts the approach by having different regions emit only the desired wavelengths directly, turning the limitation of broad-spectrum emission into a benefit through spatially selective color emission.
4Device complexity
If the color filter method is used, then manufacturing complexity is reduced, but light use efficiency deteriorates due to poor light color purity
Solution Approach 1:
The light-emitting layer is segmented into multiple regions, each emitting a specific color, eliminating the need for color filters. This maintains simple manufacturing while improving light use efficiency by ensuring that each region emits only the desired wavelength range without filtering out useful light.
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
The proposed solution enables high color purity, high display quality, low power consumption, and high yield, suitable for both high-resolution and large-sized displays, by optimizing light extraction and emission efficiency through the use of microcavity structures and semi-transmissive layers.
Implementation Method 1
Light-emitting elements (also referred to as EL elements) utilizing electroluminescence (hereinafter referred to as EL)
Implementation Method 2
Reflectivity with respect to visible light of the semi-transmissive layer is higher than reflectivity with respect to visible light of the common electrode
Data Source
AI summary
A display device which exhibits light with high color purity is provided. A display device with low power consumption is provided. An embodiment is a display device which includes a first pixel electrode, a second pixel electrode, a light-emitting layer, a common electrode, a first protective layer, and a semi-transmissive layer. The light-emitting layer includes a first region positioned over the first pixel electrode and a second region positioned over the second pixel electrode. The common electrode is positioned over the light-emitting layer. The first protective layer is positioned over the common electrode. The semi-transmissive layer is positioned over the first protective layer. Reflectivity with respect to visible light of the semi-transmissive layer is higher than reflectivity with respect to visible light of the common electrode. The semi-transmissive layer does not overlap with the first region and overlaps with the second region. For example, the semi-transmissive layer may include an opening in a position overlapping with the first region.