Thin film transistor circuit and display utilizing the same

A thin film transistor circuit comprising:

• a current mirror circuit which includes at least first through 2n-th (n.gtoreq.1 where n is a natural number) thin film transistors having a common gate electrode potential and (2n+1)-th through 2m-th (m.gtoreq.n+1 where m is a natural number) thin film transistors having a common gate electrode potential and in which the gate electrodes of the first through 2n-th thin film transistors or the (2n+1)-th through 2m-th thin film transistors are connected to the sources or drains, wherein:
• channel formation regions of a j-th (2n-1.gtoreq.j.gtoreq.1 where j is a natural number) thin film transistor and a (j+1)-th thin film transistor among the first through 2n-th thin film transistors to which the first input signal is input are arranged to be point-symmetric on a plane;
• channel formation regions of an i-th (2m-1.gtoreq.i.gtoreq.2n where i is a natural number) thin film transistor and an (i+1)-th thin film transistor among the (2n+1)-th through 2m-th thin film transistors to which the second input signal is input are arranged to be point-symmetric on a plane;
• and
• the symmetry centers of the channel formation regions of the first through 2n-th thin film transistors and the symmetry centers of the channel formation regions of the (2n+1)-th through 2m-th thin film transistors are the same points.

A thin film transistor circuit comprising:

• a differential circuit including at least first through 2k-th (k.gtoreq.1 where k is a natural number) thin film transistors having a common gate electrode potential to which a first input signal is input and (2k+1)-th through 2l-th (1.gtoreq.k+1 where 1 is a natural number) thin film transistors having a common gate electrode potential to which a second input signal is input;
• and
• a current mirror circuit which includes at least first through 2n-th (n.gtoreq.1 where n is a natural number) thin film and (2n+1)-th through 2m-th (m.gtoreq.n+1 where m is a natural number) thin film transistors having a common gate electrode potential and in which the gate electrodes of the first through 2n-th thin film transistors or the (2n+1)-th through 2m-th thin film transistors are connected to the sources or drains, wherein:
• the source-drain polarity of the thin film transistors in the differential circuit and the source-drain polarity of the thin film transistors in the current mirror circuit are opposite to each other and the sources or drains of the first through 2k-th thin film transistors of the differential circuit are connected to the sources or drains of the first through 2n-th thin film transistors of the current mirror circuit;
• the sources or drains of the (2k+1)-th through 2l-th thin film transistors of the differential circuit are connected to the sources or drains of the (2n+1)-th through 2m-th thin film transistors of the current mirror circuit;
• the sources or drains of the first through 2k-th thin film transistors of the differential circuit which are not connected to the current mirror circuit are connected to the sources or drains of the (2k+1)-th through 2l-th thin film transistors;
• an output signal is taken out from a portion of the current mirror circuit connected to the differential circuit where the gate electrodes of either first through 2n-th thin film transistors or (2n+1)-th through 2m-th thin film transistors are not connected to the source or drains;
• channel formation regions of a g-th (2k-1.gtoreq.g.gtoreq.1 where g is a natural number) thin film transistor and a (g+1)-th thin film transistor among the first through 2k-th thin film transistors of the differential circuit to which the first input signal is input are arranged to be point-symmetric on a plane;
• channel formation regions of an h-th (2l-1.gtoreq.h.gtoreq.2k where h is a natural number) thin film transistor and an (h+1)-th thin film transistor among the (2k+1)-th through 2l-th thin film transistors to which the second input signal is input are arranged to be point-symmetric on a plane;
• the symmetry centers of the channel formation regions of the first through 2n-th thin film transistors and the symmetry centers of the channel formation regions of the (2n+1)-th through 2m-th thin film transistors are the same points;
• channel formation regions of a j-th (2n-1.gtoreq.j.gtoreq.1 where j is a natural number) thin film transistor and a (j+1)-th thin film transistor among the first through 2n-th thin film transistors are arranged to be point-symmetric on a plane;
• channel formation regions of an i-th (2m-1.gtoreq.i.gtoreq.2n where i is a natural number) thin film transistor and an (i+1)-th thin film transistor among the (2n+1)-th through 2m-th thin film transistors of the current mirror circuit are arranged to be point-symmetric on a plane;
• and
• the symmetry centers of the channel formation regions of the first through 2n-th thin film transistors and the symmetry centers of the channel formation regions of the (2n+1)-th through 2m-th thin film transistors are the same points.