OLED Display Panel Continuous Emissive Layers and Color Filters
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Solution Overview
Problem
High-resolution organic light emitting diode (OLED) displays face challenges in accurately patterning emissive layers at high pixel densities due to difficulties in aligning small shadow masks and non-uniformities in emissive layers, leading to inefficiencies and energy wastage in color filtering processes.
Innovation Solution
The use of substantially continuous emissive organic layers deposited across continuous regions of a display panel, combined with strategically placed color filters to selectively transmit light from distinct subsets of pixels, allowing for high-resolution color displays with reduced energy consumption and extended operational lifetimes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shadow masks with small holes are used to pattern emissive layers at high pixel density, then manufacturing precision is improved, but alignment accuracy deteriorates due to difficulties in accurately aligning small holes
Solution Approach 1:
The patent divides the display panel into multiple banks, where each bank contains a subset of pixels (e.g., red, green, blue subpixels) that share common emissive layer regions. This segmentation allows the emissive layers to be deposited continuously across multiple pixels within a bank without requiring precise alignment of shadow mask holes for each individual pixel, thereby resolving the alignment accuracy problem while maintaining manufacturing precision.
2Manufacturing precision
If shadow masks are used to precisely pattern emissive layers, then manufacturing precision is improved, but device complexity increases due to the need for multiple shadow masks and alignment procedures
Solution Approach 1:
The patent merges the patterning function for multiple pixels into a single continuous emissive layer deposition process within each bank. Instead of using separate shadow masks for each pixel, the same shadow mask is used to deposit emissive layers across multiple pixels simultaneously, and adjacent banks share common emissive layer regions. This merging approach maintains manufacturing precision while significantly reducing device complexity by eliminating the need for multiple alignment procedures.
3Ease of manufacture
If color filters are used to create color displays from white emissive layers, then ease of manufacture is improved, but energy efficiency deteriorates due to power waste from filtering out generated light
Solution Approach 1:
The patent applies color filtering selectively only to specific regions (certain banks or subsets of pixels) rather than uniformly across the entire display panel. Different banks can use different color filter configurations, allowing the display to maintain color accuracy where filtering is applied while minimizing energy waste in regions where filtering is omitted or reduced. This local quality approach preserves ease of manufacture while improving energy efficiency.
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 high-resolution color displays with improved energy efficiency and extended operational lifetimes by reducing the need for extensive color filtering and minimizing the degradation of emissive materials, while maintaining high display brightness and color accuracy.
Implementation Method 1
Light is generated within the emissive layer due to recombination of holes and electrons passing through the layer in opposite directions. Accordingly, the intensity of emitted light is controlled by the amount of current flowing through the emissive layer
Implementation Method 2
Color filters are situated to partially block light from at least some of the emissive regions such that primary additive colors are transmitted from distinct subsets of pixels on the display panel
Data Source
AI summary
An arrangement for a high resolution active matrix display includes organic emissive layers of distinct colors each deposited across continuous regions so as to include more than one pixel emissive region. Color filters are situated to partially block light from at least some of the emissive regions such that primary additive colors are transmitted from distinct subsets of pixels. The emissive layers may be deposited in alternating parallel stripes along rows or columns of the display, or may be oriented perpendicularly with respect to one another such that the emissive layers overlap in the emissive regions of at least some pixels. In some examples, red, green, and blue of pixels are arranged in regular patterns across the display and with the emissive regions for the blue pixels forming a relatively larger area of the display than either the red or green pixels.