Semiconductor integrated circuit and liquid crystal display appratus

A method for translating image signals between a source region and a drain region of a transistor through a well region, using a liquid crystal device, the liquid crystal device comprising of a semiconductor substrate, an insulating layer arranged on the semiconductor substrate, a plurality of pixel switching devices on the insulating layer, a pixel electrode connected to each of the plurality of the pixel switching devices, and a translation switching device for providing an image signal to the pixel switching device;

• wherein the translation switching device is composed of a field effect transistor formed on the insulating layer overlaying the semiconductor substrate and the pixel switching device is composed of a field effect transistor formed on the insulating layer, the semiconductor substrate under which is removed, the field effect transistor having a source and drain region, the source and drain regions comprising a first conduction type semiconductor, the well region comprising a second conduction type semiconductor and being arranged between the source and drain regions of the field effect transistor, an ion dopant concentration of the well of the field effect transistor composing the translation switching device being greater than an ion dopant concentration of the well of the field effect transistor composing the pixel switching device, said method comprising the step of:
• translating signals under a condition such that a threshold voltage of the transistor has been altered by applying a first voltage to the well region and a second voltage to the semiconductor substrate so as to satisfy one of the following conditions (a) and (b):
• (a) wherein the well region is comprised of a p-type semiconductor, and VDMIN>VSS+Vth+ΔVth, wherein VDMIN is a minimum voltage of the image signals, VSS is a minimum voltage in the semiconductor circuit and the second voltage applied to the semiconductor substrate, Vth is a threshold voltage of the transistor in a state of not applying a voltage to both of the semiconductor substrate and the well region, ΔVth is a change amount of the threshold voltage of the transistor caused by applying the first voltage to the well region and the second voltage to the semiconductor substrate, respectively;
• and
• (b) wherein the well region is comprised of an n-type semiconductor, and VDMAX<VDD+Vth+ΔVth, wherein VDMAX is a maximum voltage of the image signals, VDD is a maximum voltage in the semiconductor circuit and the second voltage applied to the semiconductor substrate, Vth is a threshold voltage of the transistor in a state of not applying a voltage to both of the semiconductor substrate and the well region, ΔVth is a change amount of the threshold voltage of the transistor caused by applying the first voltage to the well region and the second voltage to the semiconductor substrate, respectively.