Sensor element and method of driving sensor element, and input device, display device with input function and communication device

1. A sensor element comprising two diode elements connected in series to each other, and a capacitive element having one end connected to a junction point between the two diode elements, wherein each of the diode elements includes:

a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction;

an anode electrode connected to the p-type semiconductor region;

a cathode electrode connected to the n-type semiconductor region;

a gate insulting film adjoining the semiconductor layer in a stacking direction; and

a gate electrode facing the semiconductor layer with the gate insulating film in between, and further wherein for each diode, the gate electrode is an intrinsic semiconductor gate electrode adjacent the gate insulating film.

2. The sensor element according to claim 1 , wherein

the semiconductor layer has an intrinsic semiconductor region between the p-type semiconductor region and the n-type semiconductor region.

3. The sensor element according to claim 1 , wherein

each of the diode elements generates electric charge in response to light or heat applied to the semiconductor layer.

4. The sensor element according to claim 1 , wherein

each of the diode elements is formed on a substrate, and

the gate insulating film and the gate electrode are formed on the substrate side of the semiconductor layer.

5. The sensor element according to claim 1 , wherein

each of the diode elements is formed on the substrate, and

the gate insulating film and the gate electrode are formed on a opposite side of the semiconductor layer from the substrate.

6. The sensor element according to claim 1 , wherein

each of the diode elements is formed on the substrate,

the gate insulating film and the gate electrode are formed on the substrate side of the semiconductor layer, and

each of the diode elements includes:

a second gate insulating film formed on a opposite side of the semiconductor layer from the gate insulating film; and

a second gate electrode facing the semiconductor layer with the second gate insulating film in between.

7. A method of driving a sensor element, the sensor element including:

two diode elements connected in series to each other, each of the diode elements including a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction, an anode electrode connected to the p-type semiconductor region, a cathode electrode connected to the n-type semiconductor region, a gate insulting film adjoining the semiconductor layer in a stacking direction, and a gate electrode facing the semiconductor layer with the gate insulating film in between; and

a capacitive element having one end connected to a junction point between the two diode elements,

the method comprising:

controlling relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element; and

controlling relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, thereby to turn on and off the two diode elements separately from each other, and further wherein for each diode, the gate electrode is an intrinsic semiconductor gate electrode adjacent the gate insulating film.

8. The method of driving the sensor element according to claim 7 , wherein

the semiconductor layer includes an intrinsic semiconductor region between the p-type semiconductor region and the n-type semiconductor region.

9. A method of driving a sensor element, the sensor element including:

two diode elements connected in series to each other, each of the diode elements including a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction, an anode electrode connected to the p-type semiconductor region, a cathode electrode connected to the n-type semiconductor region, a gate insulting film adjoining the semiconductor layer in a stacking direction, and a gate electrode facing the semiconductor layer with the gate insulating film in between: and

a capacitive element having one end connected to a junction point between the two diode elements,

the method comprising:

controlling relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element: and

controlling relationship of electric -potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, thereby to turn on and off the two diode elements separately from each other, wherein

the relationship of the electric potential between the cathode electrode and the gate electrode in the first diode element, and the relationship of the electric potential between the anode electrode and the gate electrode in the second diode element are controlled so that following relationship are satisfied, where φ 1 (on) is an on-state voltage of the gate electrode and φ 1 (off) is an off-state voltage of the gate electrode in the first diode element, and φ 2 (on) is an on-state voltage of the gate electrode and φ 2 (off) is an off-state voltage of the gate electrode in the second diode element

φ1(on)<φ1(off),

φ2(on)>φ2(off).

10. A method of driving a sensor element, the sensor element including;

two diode elements connected in series to each other, each of the diode elements including a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction, an anode electrode connected to the a-type semiconductor region, a cathode electrode connected to the n-type semiconductor region, a gate insulting film adjoining the semiconductor layer in a stacking direction, and a gate electrode facing the semiconductor layer with the gate insulating film in between; and

a capacitive element having one end connected to a junction point between the two diode elements,

the method comprising:

controlling relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element; and

controlling relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, thereby to turn on and off the two diode elements separately from each other, wherein

the relationship of the electric potential between the cathode electrode and the gate electrode in the first diode element, and the relationship of the electric potential between the anode electrode and the gate electrode in the second diode element are controlled so that following relationship are satisfied, where V 1 (on) is an on-state voltage of the cathode electrode and V 1 (off) is an off-state voltage of the cathode electrode in the first diode element, and V 2 (on) is an on-state voltage of the anode electrode and V 2 (off) is an off-state voltage of the anode electrode in the second diode element

V1(on)<V1(off)

V2(on)>V2(off).

11. A method of driving a sensor element, the sensor element including:

two diode elements connected in series to each other, each of the diode elements including a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction, an anode electrode connected to the p-type semiconductor region, a cathode electrode connected to the n-type semiconductor region, a gate insulting film adjoining the semiconductor layer in a stacking direction, and a gate electrode facing the semiconductor layer with the gate insulating film in between; and

a capacitive element having one end connected to a junction point between the two diode elements,

the method comprising;

controlling relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element; and

controlling relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, thereby to turn on and off the two diode elements separately from each other, wherein

the relationship of the electric potential between the cathode electrode and the gate electrode in the first diode element, and the relationship of the electric potential between the anode electrode and the gate electrode in the second diode element are controlled so that following relationship are satisfied, where φ 1 (on) is the on-state voltage of the gate electrode and φ 1 (off) is the off-state voltage of the gate electrode in the first diode element, and φ 2 (on) is the on-state voltage of the gate electrode and φ 2 (off) is the off- state voltage of the gate electrode in the second diode element

φ1(on)>φ1(off)

φ2(on)<φ2(off).

12. A method of driving a sensor element, the sensor element including:

two diode elements connected in series to each other, each of the diode elements including a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction, an anode electrode connected to the p-type semiconductor region, a cathode electrode connected to the n-type semiconductor region, a gate insulting film adjoining the semiconductor layer in a stacking direction, and a gate electrode facing the semiconductor layer with the gate insulating film in between; and

a capacitive element having one end connected to a junction point between the two diode elements,

the method comprising:

controlling relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element: and

controlling relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, thereby to turn on and off the two diode elements separately from each other, wherein

the relationship of the electric potential between the cathode electrode and the gate electrode in the first diode element, and the relationship of the electric potential between the anode electrode and the gate electrode in the second diode element are controlled so that following relationship (1) and (2) are satisfied with φ 1 and φ 2 when the first diode element is turned on and the second diode element is turned off, and so that following relationship (3) and (4) are satisfied with φ 1 and φ 2 when the first diode element is turned off and the second diode element is turned on, where Vgl is a rise voltage defined as a specific gate voltage where output current rapidly increases and Vg 2 is a fall voltage defined as a specific gate voltage where the output current rapidly decreases when the gate voltage is gradually raised in the first diode element, Vg 3 is a rise voltage defined as a specific gate voltage where output current rapidly increases and Vg 4 is a fall voltage defined as a specific gate voltage where the output current rapidly decreases when the gate voltage is gradually raised in the second diode element, and φ 1 is a voltage of the gate electrode in the first diode element and φ 2 is a voltage of the gate electrode in the second diode element

Vg1<φ1<Vg2  (1)

φ2<Vg3  (2)

Vg2<φ1  (3)

Vg3<φ2<Vg4  (4).

13. A method of driving a sensor element. the sensor element including:

two diode elements connected in series to each other, each of the diode elements including a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction, an anode electrode connected to the p-type semiconductor region, a cathode electrode connected to the n-type semiconductor region, a gate insulting film adjoining the semiconductor layer in a stacking direction, and a gate electrode facing the semiconductor layer with the gate insulating film in between; and

a capacitive element having one end connected to a junction point between the two diode elements,

the method comprising:

controlling relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive elements; and

controlling relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, thereby to turn on and off the two diode elements separately from each other, wherein

the relationship of the electric potential between the cathode electrode and the gate electrode in the first diode element, and the relationship of the electric potential between the anode electrode and the gate electrode in the second diode element are controlled so that following relationship (5) and (6) are satisfied with φ 1 and φ 2 when the first diode element is turned on and the second diode element is turned off, and so that following relationship (7) and (8) are satisfied with φ 1 and φ 2 when the first diode element is turned off and the second diode element is turned on, where Vg 1 is a rise voltage defined as a specific gate voltage where output current rapidly increases and Vg 2 is a fall voltage defined as a specific gate voltage where the output current rapidly decreases when the gate voltage is gradually raised in the first diode element, Vg 3 is a rise voltage defined as a specific gate voltage where output current rapidly increases and Vg 4 is a fall voltage defined as a specific gate voltage where the output current rapidly decreases when the gate voltage is gradually raised in the second diode element, and φ 1 is a voltage of the gate electrode in the first diode element and φ 2 is a voltage of the gate electrode in the second diode element.

Vg1<φ1<Vg2  (5)

Vg4<φ2  (6)

φ1<Vg1  (7)

Vg3<φ2<Vg4  (8).

14. A method of driving a sensor element, the sensor element including:

two diode elements connected in series to each other, each of the diode elements including a semiconductor layer having p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction, an anode electrode connected to the n-type semiconductor region, a cathode electrode connected to the n-type semiconductor region, a gate insulting film adjoining the semiconductor layer in a stacking direction, and a gate electrode facing the semiconductor layer with the gate insulating film in between: and

a capacitive element having one end connected to a junction point between the two diode elements,

the method comprising:

controlling relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element; and

controlling relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, thereby to turn on and off the two diode elements separately from each other, wherein

in such a case that signal light or signal heat is intermittently applied to the semiconductor layer, only one of the first diode element and the second diode element is turned on when signal light or signal heat is applied to the semiconductor layer, and

only one of the first diode element and the second diode element, which is turned off when the signal light or the signal heat is applied to the semiconductor layer, is turned on when the signal light or the signal heat is not applied to the semiconductor layer.

15. An input device comprising a plurality of sensor elements arranged in a matrix form in a plane and a drive section driving the plurality of sensor elements, each of the sensor elements including two diode elements connected in series to each other and a capacitive element having one end connected to a junction point between the two diode elements, each of the diode elements including:

a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction;

an anode electrode connected to the p-type semiconductor region;

a cathode electrode connected to the n-type semiconductor region;

a gate insulting film adjoining the semiconductor layer in a stacking direction; and

a gate electrode facing the semiconductor layer with the gate insulating film in between, wherein

the drive section turns on and off the two diode elements separately from each other through controlling:

relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element; and

relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, and further wherein for each diode, the gate electrode is an intrinsic semiconductor gate electrode adjacent the gate insulating film.

16. The input device according to claim 15 , further comprising:

a light source arranged in back of the plurality of sensor elements.

17. A display device with an input function comprising a plurality of display elements and a plurality of sensor elements arranged in a matrix form in a plane and a drive section driving the plurality of display elements and the plurality of sensor elements, each of the sensor elements including two diode elements connected in series to each other and a capacitive element having one end connected to a junction point between the two diode elements, each of the diode elements including:

a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction;

an anode electrode connected to the p-type semiconductor region;

a cathode electrode connected to the n-type semiconductor region;

a gate insulting film adjoining the semiconductor layer in a stacking direction; and

a gate electrode facing the semiconductor layer with the gate insulating film in between, wherein

the drive section turns on and off the two diode elements separately from each other through controlling:

relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element; and

relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, and further wherein for each diode, the gate electrode is an intrinsic semiconductor gate electrode adjacent the gate insulating film.

18. A communication device comprising one or more sensor elements and a drive section driving the plurality of sensor elements, each of the sensor elements including two diode elements connected in series to each other and a capacitive element having one end connected to a junction point between the two diode elements, each of the diode elements including:

a semiconductor layer having a p-type semiconductor region and an n-type semiconductor region facing each other in an in-plane direction;

an anode electrode connected to the p-type semiconductor region;

a cathode electrode connected to the n-type semiconductor region;

a gate insulting film adjoining the semiconductor layer in a stacking direction; and

a gate electrode facing the semiconductor layer with the gate insulating film in between, wherein

the drive section turns on and off the two diode elements separately from each other through controlling:

relationship of electric potential between the cathode electrode and the gate electrode in a first diode element as one of the two diode elements, the anode electrode of the first diode element being connected to the capacitive element; and

relationship of electric potential between the anode electrode and the gate electrode in a second diode element as the other of the two diode elements, the cathode electrode of the second diode element being connected to the capacitive element, and further wherein for each diode, the gate electrode is an intrinsic semiconductor gate electrode adjacent the gate insulating film.