| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve the problem that a liquid crystal display device composed especially of a low-temperature polysilicon TFT becomes weak to an electric current surge and a voltage noise when using a MOS TFT in a signal input part since the refuge of the surge current by an input signal decreases because a power supply voltage is large compared with a semiconductor circuit, such as a DRAM. SOLUTION: In the signal input part of the liquid crystal panel, an input output protective transistor 14 is constituted of a TFT of a Non LDD. The source side of the transistor 14 is connected to a resistor 15 having the function of a light shielding layer and electric current by pass. The resistor 15 has the pattern of an reversal spiral shape, and the function of a coil 17 for reducing the electric current surge equivalently is given. Furthermore, one end of the light shielding layer is grounded, a capacitance 18 is formed between the drain part of the TFT and the light shielding layer, and the potential (substrate potential) of the drain part is fixed. As a result, the operation of the input/output circuit is stabilized.</p> |
