Semiconductor Device Threshold Voltage Correction Circuit
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Solution Overview
Problem
Display devices face challenges in achieving high-resolution, multi-tone, and wide color gamut displays due to variations in driving transistor characteristics, which affect image quality and require effective correction of image data.
Innovation Solution
A semiconductor device with a pixel circuit incorporating an image data retention portion, a correction data retention portion, a driver circuit, and a threshold voltage correction circuit, utilizing transistors with metal oxide or silicon in the channel formation region to reduce variations and correct threshold voltage, thereby improving image data accuracy and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional pixel circuit without threshold voltage correction is used, then the circuit area and power consumption are smaller, but the display quality deteriorates due to variations in driving transistor characteristics
Solution Approach 1:
The pixel circuit is segmented into functional modules: image data retention portion (first capacitor), correction data retention portion (second capacitor), and driver circuit portion. This segmentation allows independent optimization of each module, enabling threshold voltage correction functionality to be added without proportionally increasing overall circuit area.
Solution Approach 2:
The pixel circuit is designed to perform multiple functions: storing image data, storing correction data, correcting threshold voltage variations, and driving the display element. By integrating these functions into a single pixel circuit structure, the patent avoids adding separate correction circuits that would increase circuit area.
2Measurement precision
If a conventional pixel circuit without threshold voltage correction is used, then the circuit area and power consumption are smaller, but the image data accuracy deteriorates
Solution Approach 1:
The circuit performs preliminary action by correcting threshold voltage variations and storing correction data before the actual display operation. The correction data is prepared in advance in the correction data retention portion, allowing accurate image data processing without requiring additional power during the display period.
Solution Approach 2:
The patent changes the electrical parameters of the driving transistor by applying a correction voltage to the back gate, which adjusts the threshold voltage to compensate for variations. This parameter change enables accurate image data representation without requiring higher power consumption.
3Reliability
If transistors with metal oxide or silicon are used in the channel formation region, then variations in driving transistor characteristics are reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent employs composite material structures in the transistor channel formation region, combining metal oxide semiconductor layers with silicon-based layers. This composite structure leverages the low off-state current characteristics of metal oxide semiconductors and the mature processing of silicon technologies, achieving stable transistor characteristics while maintaining compatibility with existing manufacturing processes.
Data Source
AI summary
A semiconductor device that reduces variations in the characteristics of driving transistors and corrects image data is provided. The semiconductor device includes an image data retention portion, a correction data retention portion, a driver circuit portion, a display element, and a threshold voltage correction circuit portion. The image data retention portion has a function of retaining first image data, and the correction data retention portion has a function of retaining correction data, and a function of generating second image data corresponding to the first image data and the correction data when the first image data is retained in the image data retention portion. The driver circuit portion has a function of generating a current corresponding to the second image data and feeding the current to the display element, and the threshold voltage correction circuit portion has a function of correcting a threshold voltage of a driving transistor in the driver circuit portion. With the above structure, the semiconductor device can correct the image data, correct the threshold voltage of the driving transistor, and perform display based on the second image data.