Patent ID: 6914956

Claim:
A shift register comprising: a plurality of pulse generation portions for generating a series of pulse signals in response to a level change of inputted clock signals; and a plurality of shift pulse generation units, wherein a part of the plurality of pulse generation portions belongs to one of the shift pulse generation units, and each part of the plurality of pulse generation portions belongs to different shift pulse generation units, and the plurality of shift pulse generation units has a predetermined shift pulse generation unit, and wherein the predetermined shift pulse generation unit has a status signal generation circuit for outputting a status signal, which shows a status that at least one pulse generation portion which belongs to the predetermined shift pulse generation unit generated a pulse signal, to common wiring to which both of an earlier shift pulse generation unit, which outputs a pulse signal earlier than the predetermined shift pulse generation unit, and a later shift pulse generation unit, which outputs a pulse signal later than the predetermined shift pulse generation unit, are connected, and a clock supply circuit for supplying a clock signal to the pulse generation portion which belongs to the predetermined shift pulse generation unit, and wherein there is a first period in which the clock supply circuit supplies the clock signal to the pulse generation portion which belongs to the predetermined shift pulse generation unit and a second period in which the clock signal is not supplied, and during the first period in which the clock signal is supplied, the status signal, which shows a status that at least one pulse generation portion, which belongs to the earlier shift pulse generation unit than the predetermined shift pulse generation unit, generated pulse signals, is inputted from the earlier shift pulse generation unit, and the status signal, which shows a status that the pulse generation portion which belongs to the later shift pulse generation unit generated pulse signals, is not inputted from the later shift pulse generation unit, and the status signal, for showing such a status that the pulse generation portion generated pulse signals, is a signal which is more difficult to be deteriorated on the common wiring than the pulse signal.