Driver Circuit Amplifying Photocurrent for Weak Signal Readout
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Solution Overview
Problem
Conventional passive 2T1C structures in liquid crystal displays suffer from a weak light-generated current signal, leading to ineffective signal reading and display functionality due to the inability to amplify the induced current effectively.
Innovation Solution
A driver circuit comprising a first thin film transistor to induce photocurrent, a second thin film transistor to amplify the photocurrent, a third thin film transistor to control reading timing, and additional storage capacitors to enhance signal stability and intensity, along with a fourth thin film transistor to reset the photocurrent, improving the signal-noise ratio and stability of the output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive 2T1C structure is used for laser sensing and signal reading, then the circuit can achieve light source signal read function and cyclical read-out function, but the induced current generated by the sensor TFT is too weak and the readout signal is too weak for the liquid crystal display to effectively identify and read
Solution Approach 1:
The patent introduces an amplifier TFT as an intermediary component between the sensor TFT and the readout line. This amplifier TFT receives the weak induced current from the sensor TFT and amplifies it before outputting to the readout line, thereby solving the problem of weak signal intensity without affecting the passive 2T1C structure's basic sensing and cyclical readout functions
Solution Approach 2:
The patent changes the electrical parameters of the circuit by adding the amplifier TFT, which modifies the current gain parameter. The amplifier TFT has a higher current gain than the sensor TFT, thereby transforming the weak photocurrent into a stronger signal suitable for effective readout by the liquid crystal display
2Power
If additional transistors and capacitors are added to amplify the photocurrent and improve signal reading, then the signal intensity and stability are enhanced, but the device complexity increases
Solution Approach 1:
The patent segments the circuit into distinct functional modules: the sensor TFT for light detection, the amplifier TFT for signal amplification, and the storage capacitor for signal holding. This segmentation allows each component to perform its specific function efficiently while maintaining a relatively simple overall structure that can be integrated into the display driver
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
The proposed driver circuit and method significantly enhance the signal intensity and stability of the photocurrent readout, addressing the weakness of conventional systems by amplifying the photocurrent and improving the signal-noise ratio, thereby improving the display functionality of liquid crystal displays.
Implementation Method 1
the sensor TFT generates an induced current I
Data Source
AI summary
The present invention discloses a driver circuit and a driving method thereof including a first thin film transistor, a second thin film transistor, and a third thin film transistor. Increasing a photocurrent of the second thin film transistor, i.e., amplifying the photocurrent of the thin film transistor to a photosensitive thin film transistor, advantages enhancement of a signal intensity and a signal-noise ratio of the photocurrent read out by the read line to solve the issue of weak a photocurrent signal from the photosensitive display.