OLED Pixel Circuit Resistor Masking Luminance Variation
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Solution Overview
Problem
The manufacturing of organic light-emitting diode (OLED) displays using liquid deposition techniques often results in systematic luminance variations due to non-uniformities in the deposition of organic semiconductor materials, leading to irregular patterns and reduced manufacturing yield.
Innovation Solution
Incorporating resistors with a resistor density of zero to 1×10−7 Ω/μm² into the pixel circuits between the electrodes, either between the thin film transistor and the organic light-emitting diode or between the electrodes, to introduce random variations that mask systematic luminance irregularities, thereby improving manufacturing tolerance and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid deposition techniques are used to manufacture OLED displays, then manufacturing complexity is reduced and ease of manufacture is improved, but systematic luminance variations and patterned irregularities occur in the display quality
Solution Approach 1:
The patent introduces resistors with specifically controlled resistance values (ranging from 100 to 1000 ohms) into the pixel circuits to compensate for systematic luminance variations. By adjusting the resistance parameters, the current through each pixel can be fine-tuned to counteract the patterned irregularities caused by liquid deposition non-uniformities, thereby improving luminance uniformity while maintaining the ease of liquid deposition manufacturing
Solution Approach 2:
The patent measures the actual luminance output of each pixel and creates a compensation map that copies the pattern of variations. This compensation map is then used to assign specific resistor values to each pixel circuit, effectively creating a digital twin of the non-uniformity pattern and using it to generate corrective resistance values that mask the systematic variations
2Manufacturing precision
If resistors are added to pixel circuits to mask systematic luminance variations, then luminance uniformity is improved, but device complexity increases
Solution Approach 1:
The patent combines the resistor element with existing structures in the pixel circuit, such as integrating the resistor into the thin-film transistor layout or placing it in series with the OLED within the same pixel structure. This merging approach adds the necessary compensation function without significantly increasing the overall device footprint or structural complexity
Solution Approach 2:
The patent applies local quality by introducing resistors only in the specific locations where systematic luminance variations occur, rather than uniformly across all pixels. Each resistor is strategically placed and sized based on the local non-uniformity pattern, allowing compensation to be applied precisely where needed while minimizing overall device complexity
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 raises the acceptable quality threshold for display devices from 1-2% to 5% by effectively masking regular patterns of luminance irregularities, enhancing the uniformity and quality of the display devices.
Implementation Method 1
Incorporating resistors with a resistor density of zero to 1×10−7 Ω/μm² into the pixel circuits between the electrodes
Implementation Method 2
an organic light emitting diode
Data Source
AI summary
An electrical device containing pixel circuits, where at least one resistor is present within one pixel circuit to mask systematic luminance variation in organic light emitting diodes. The resistor can be located at one or more locations between electrodes. Each resistor has a defined resistor density, with distinct resistor values among pixel circuits to produce random variations in pixel luminance across a display containing plurality of pixel circuits.