Single-Type TFT Voltage Level Shifter for Simpler LCD Fabrication
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Solution Overview
Problem
Conventional voltage level shifters for TFT LCDs require multiple doping MOS processes, leading to increased manufacturing steps and costs due to the coexistence of NMOS and PMOS TFTs.
Innovation Solution
A voltage level shifter is designed using single-typed TFTs, specifically P-type TFTs, with specific electrical couplings between terminals to simplify the circuit and reduce manufacturing complexity, while maintaining effective signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional voltage level shifters use both NMOS and PMOS TFTs, then the voltage level shifting function is achieved, but the manufacturing process complexity and cost increase due to multiple doping MOS processes
Solution Approach 1:
The patent applies homogeneity by using only single-typed TFTs (either all NMOS or all PMOS) throughout the voltage level shifter circuit, eliminating the need for multiple doping processes required by conventional mixed NMOS-PMOS designs. This uniform approach simplifies manufacturing while maintaining the voltage level shifting function through carefully designed electrical couplings between the single-typed TFTs
2Reliability
If conventional voltage level shifters use multiple doping MOS processes, then both NMOS and PMOS TFTs can be integrated, but processing steps and manufacture cost increase
Solution Approach 1:
The patent extracts and eliminates one of the two doping processes (either NMOS or PMOS) from the manufacturing sequence by designing the voltage level shifter to function with only single-typed TFTs. This extraction of the unnecessary doping process reduces manufacturing steps and improves productivity while the remaining single-typed TFT configuration maintains sufficient voltage level shifting performance through optimized circuit topology
Data Source
AI summary
A voltage level shifter formed by single-typed transistors comprises two input terminals, two power supply terminals, a plurality of thin-film transistors, and an output terminal. Another voltage level shifter formed by single-typed transistors comprises two input terminals, an output terminal, two power supply terminals, two input units, a first thin-film transistor, a disable unit, a feedback unit, and a second thin-film transistor. The voltage level shifters are formed by single-typed TFTs. When integrating the voltage level shifters into a substrate of a TFT display, the manufacturing processes are simplified. Besides, power is saved.