OLED Display Device with Segmented Light-Emitting Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current OLED display devices face challenges in achieving high definition and low power consumption due to lower vapor deposit process accuracy, leading to decreased light extraction efficiency and shorter element lifetime.
Innovation Solution
A light-emitting element display device is designed with a thin film transistor substrate and a color filter substrate, featuring a first light-emitting layer covering the entire display region and a second light-emitting layer covering independent regions, emitting different wavelength regions to enhance light extraction efficiency and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vapor deposit process is used for manufacturing OLED display device, then light emitting elements can be formed, but manufacturing precision is lower leading to larger space between pixels
Solution Approach 1:
The display device is divided into multiple light emitting elements (first and second light emitting layers) that are spatially segmented and independently controlled. Each light emitting layer emits different wavelength regions, allowing precise control over the light output from each pixel region without requiring high-precision vapor deposit processes for the entire display.
Solution Approach 2:
The patent introduces a vertical dimension by stacking multiple light emitting layers (first light emitting layer and second light emitting layer) at different heights. This multi-layer structure allows the system to achieve high definition through vertical separation of light emission functions rather than relying solely on horizontal precision in the vapor deposit process.
2Ease of manufacture
If space between pixels is increased to accommodate lower vapor deposit accuracy, then manufacturing becomes easier, but definition decreases
Solution Approach 1:
By adding vertical stacking of light emitting layers, the patent transforms a two-dimensional pixel arrangement problem into a three-dimensional structure. This allows larger horizontal spacing between pixels (easier manufacturing) while maintaining high definition through the vertical separation and spectral differentiation of multiple light emitting layers.
Solution Approach 2:
The patent changes the spectral parameters by having different light emitting layers emit different wavelength regions. This spectral differentiation allows the system to maintain color accuracy and definition even with larger physical spacing between pixels, as each layer's unique wavelength signature provides distinct visual information.
3Measurement precision
If opening ratio is decreased to increase definition, then definition increases, but brightness decreases requiring higher current density
Solution Approach 1:
The patent segments the light emission function across multiple light emitting layers, where each layer contributes to the overall brightness. This segmentation allows the opening ratio to be reduced for higher definition while the combined light output from multiple layers maintains sufficient brightness without requiring excessive current density in any single layer.
Solution Approach 2:
The patent merges multiple light emitting layers with different wavelength emissions to produce combined light output. This merging effect allows the display to achieve high definition through reduced opening ratios while maintaining brightness through the cumulative light emission from all layers, avoiding the need for high current density that would increase power consumption.
4Illumination intensity
If current density per unit area is increased to maintain brightness with decreased opening ratio, then brightness is maintained, but element lifetime decreases
Solution Approach 1:
By segmenting the brightness function across multiple light emitting layers, each layer operates at lower current density while collectively providing the required overall brightness. This segmentation distributes the electrical stress and thermal load, preventing any single element from experiencing excessive current density that would shorten its lifetime.
5Adaptability or versatility
If tandem structure is used to extract white color, then white light emission is achieved, but light extraction efficiency decreases due to increased voltage
Solution Approach 1:
The patent applies local quality by having different light emitting layers emit different wavelength regions (e.g., blue and yellow-green) rather than using a single white light source. Each layer is optimized for its specific wavelength emission, allowing efficient light extraction at lower voltages while the color filters in the color filter substrate convert these to the desired RGB colors, including white where needed.
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 configuration allows for high-density pixel arrangement, increased opening ratio, and reduced power consumption while maintaining or improving light-emitting efficiency, thus addressing the limitations of existing OLED display devices.
Implementation Method 1
a first light-emitting layer that covers the entire display region and emits a light having one wavelength region
Implementation Method 2
a second light-emitting layer that emits a light having a wavelength region different from that of the first light-emitting layer, and covers a plurality of independent regions in the display region
Implementation Method 3
a color filter which causes a light having a predetermined wavelength region in each sub-pixel to pass
Data Source
AI summary
A light-emitting element display device including: a thin film transistor substrate that includes a transistor which controls an amount of light emission from each sub-pixel arranged on an entire display region; and a color filter substrate that is arranged to overlap with the thin film transistor substrate, and includes a color filter which causes a light having a predetermined wavelength region in each sub-pixel to pass. The thin film transistor substrate includes a first light-emitting layer that covers the entire display region and emits a light having one wavelength region, and a second light-emitting layer that emits a light having a wavelength region different from that of the first light-emitting layer, and covers a plurality of independent regions in the display region.