Display Device Driving Transistors with Segmented Unit Transistors
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Solution Overview
Problem
Oxide thin film transistors in display devices exhibit characteristic changes due to varying channel sizes, which can deteriorate display quality by increasing characteristic deviations and affecting threshold voltages and mobility.
Innovation Solution
The use of multiple unit transistors with uniform channel width and length in driving transistors and light emitting transistors within each pixel, forming different numbers of current paths to stabilize and standardize transistor characteristics across pixels, thereby reducing characteristic deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If oxide TFTs with varying channel sizes are used in display devices, then different current control characteristics are achieved for different pixels, but characteristic deviations increase and display quality deteriorates
Solution Approach 1:
The driving transistor is divided into multiple unit transistors (first, second, third unit transistors) with identical channel dimensions. Each unit transistor handles a portion of the total current, allowing the pixel to achieve different current control characteristics by activating different numbers of unit transistors while maintaining uniform manufacturing parameters for all units.
Solution Approach 2:
Different pixels are configured with different numbers of unit transistors based on their specific current control requirements. For example, first pixels may use one unit transistor while second pixels use two unit transistors, allowing local optimization of current characteristics without varying the channel size of individual unit transistors.
2Adaptability or versatility
If different channel sizes are used in driving transistors to achieve different current characteristics, then pixel-specific performance is optimized, but manufacturing precision decreases due to varying channel dimensions
Solution Approach 1:
Instead of manufacturing transistors with different channel sizes, the patent segments the transistor channel into multiple identical unit channels. Each unit transistor has the same channel width and length, ensuring uniform manufacturing precision across all pixels while still allowing different total current characteristics through parallel configuration.
Solution Approach 2:
Multiple unit transistors with identical channel dimensions are combined in parallel within a pixel to achieve the desired total current control characteristic. This merging approach maintains manufacturing precision by using uniform units while providing adaptability through variable parallel configurations.
3Manufacturing precision
If multiple unit transistors are used in driving transistors to standardize characteristics, then manufacturing precision improves with uniform channel dimensions, but device complexity increases
Solution Approach 1:
The driving transistor channel is segmented into multiple identical unit channels that can be manufactured using the same process parameters. This segmentation improves manufacturing precision by eliminating the need to control different channel dimensions while the modular structure makes the increased complexity manageable through repetition of standardized units.
Data Source
AI summary
A display device includes: a first pixel including a first organic light emitting diode and a first driving transistor for controlling a driving current flowing to the first organic light emitting diode; a second pixel including a second organic light emitting diode and a second driving transistor for controlling a driving current flowing to the second organic light emitting diode; and a third pixel including a third organic light emitting diode and a third driving transistor for controlling a driving current flowing to the third organic light emitting diode, wherein the first driving transistor, the second driving transistor, and the third driving transistor include a different number of unit transistors from one another, and the first pixel, the second pixel, and the third pixel have different colors from one another.