Electro-optical Device Overlapping Storage Capacitor
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Solution Overview
Problem
In electro-optical devices, miniaturizing pixel circuits while maintaining precise control of current to light-emitting elements is challenging due to variations in transistor threshold voltages, leading to display unevenness and difficulties in narrowing data line pitch.
Innovation Solution
The electro-optical device incorporates a substrate with a scanning line, data line, and a pixel circuit, featuring a storage capacitor with overlapping portions to achieve high capacitance in a small area, allowing for precise voltage control and reduced data line pitch, and includes a level shift circuit to compensate for transistor variations without requiring fine precision in data signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the pixel circuit is miniaturized to reduce display size and increase high definition, then the display size is reduced and resolution is increased, but the current control precision deteriorates due to micro region effects
Solution Approach 1:
The patent introduces a level shift circuit that operates in a separate voltage dimension to compress the data signal amplitude before it reaches the pixel circuit. This dimensional transformation allows the miniaturized pixel circuit to receive pre-compressed signals, maintaining control precision despite the reduced physical size and increased susceptibility to micro region effects.
Solution Approach 2:
The level shift circuit acts as an intermediary between the data signal source and the pixel circuit. It performs amplitude compression on the data signal, transforming it into a suitable form for the miniaturized pixel circuit, thereby mediating the precision control issue that arises from miniaturization.
2Speed
If the driving capability is increased to charge data lines in short time, then the charging speed is improved, but the data signal precision deteriorates
Solution Approach 1:
The level shift circuit performs preliminary action by compressing the data signal amplitude before the signal is transmitted to the pixel circuit. This pre-processing ensures that even with high-speed driving that may introduce precision losses, the signal maintains the required precision for accurate pixel control.
3Manufacturing precision
If a configuration is added to compress data signal amplitude, then the current control precision is improved, but the data line pitch increases
Solution Approach 1:
The level shift circuit is merged with the existing pixel circuit structure, sharing common elements such as the storage capacitor and transistor components. This integration allows the amplitude compression function to be added without proportionally increasing the overall pitch, as the circuit elements are combined rather than simply appended.
Solution Approach 2:
The level shift circuit utilizes existing components (such as the storage capacitor and transistors) to perform multiple functions: both signal level shifting and amplitude compression. This multi-functionality reduces the need for additional dedicated components, thereby minimizing the increase in data line pitch while achieving the desired precision improvement.
Data Source
AI summary
An electro-optical device comprises a substrate, a scanning line, a data line, a pixel circuit, and a first storage capacitor holding a first voltage corresponding to a data signal. The first storage capacitor includes a first portion and a second portion connected in parallel. The first portion and the second portion overlap when viewed from a direction orthogonal with respect to the first main surface.