Design Of Integrated Gate Driver Circuit Based On Organic Thin Film Transistor For Flexible Display

Organic thin film transistor(OTFT)has attracted extensive attention in the field of flexible electronics,especially in the field of flexible display,because of its excellent flexibility,low process cost and the advantages of large-area production.By integrating the OTFT based gate driver on array(GOA)circuit into the display panel,we can achieve more flexible,more bending and curling display pannel.In addition,integrated gate driver circuit can minimize the frame,maximize the display area,reduce the number of chips and the risk brought by the sealing process.Which can make the panel lighter and thinner,and reduce the total production cost.Therefore,the integrated gate driver circuit is a hot spot in the industry.Moreover,due to the lack of the organic thin film transistor based gate drive circuit,the organic thin film transistor based gate drive circuit needs to be discussed.First of all,this paper mainly introduces the basic concept of display and the role of transistors that plays in display applications.The characteristics of amorphous silicon thin film transistors,polycrystalline silicon thin film transistors,oxide thin film transistors and organic thin film transistors are discussed and compared in this paper.It is pointed out that organic thin film transistors have much better application background and advantages in flexible display.In addition,it also introduces the basic concept of the gate driver circuit,and makes a corresponding comparison between the new and old gate driver circuits.Secondly,the structure types of organic thin film transistors are introduced: single gate structure and dual gate structure.The single gate structure can be divided into: top gate bottom contact,bottom gate bottom contact and bottom gate top contact device structures.According to the laboratory process,the top gate bottom contact device structure is selected and used in this paper.Then,the electrical measurement of the organic thin film transistor device is carried out,and the electrical parameters of the subsequent simulation model are extracted,and the spice model which can be used for circuit simulation is fitted.Then,according to the characteristics of the organic thin film transistor prepared in the laboratory,the basic logic circuit units such as depletion inverter,NAND gate and flipflop based on p-type organic thin film transistor are designed,and ripple counter and sequential pulse generator are realized with these units.Except using the sequential pulse generator to realize the sequential clock signal,this paper also analyzes the existing problems of the gate driver circuit and according to the existing problems,a new type of depletion gate driver circuit based on p-type organic thin film transistor is designed and proposed.We compared the performance with the existing gate driver circuit's.The gate driver circuit proposed in this paper is suitable for the depletion device.The gate driver circuit that proposed in this paper has a large tolerance for the threshold voltage.At last,the circuits designed in this paper is realized and tested by the chip verification,and the function of the ripple counter in the sequential pulse trigger is realized.The rest simulation results show that the design can solve the problem of threshold voltage bias to make gate driver circuits work in proper way.