PHOTOSENSOR AND DISPLAY DEVICE

• US 20100134735A1
• Filed: 11/24/2009
• Published: 06/03/2010
• Est. Priority Date: 11/28/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: TANADA, Yoshifumi, NAKAMURA, Yasuo
• Granted Patent: US 9,450,133 B2
• Time in Patent Office: Days
• US Class Current: 349/116
• CPC Class Codes: G02F 1/13312 Circuits comprising photodetectors for purposes other than feedback
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 31/1055 the devices comprising amorphous materials of Group IV of the Periodic Table
• CPC Class Codes: H10K 59/40 OLEDs integrated with touch screens
• CPC Class Codes: H10K 59/65 OLEDs integrated with inorganic image sensors

Abstract

Thin film transistors including an oxide semiconductor containing indium, gallium, and zinc are easily arranged in a matrix over a large substrate and have small characteristic variations. With amplifier circuits and driver circuits of display elements which include the thin film transistors including an oxide semiconductor containing indium, gallium, and zinc with small characteristic variations, intensity distribution of light received by the photodiodes arranged in a matrix is converted into electrical signals with high reproducibility and output, and the display elements arranged in a matrix can be uniformly driven.

Claims

1. A photosensor comprising:

a photoelectric conversion element including a photoelectric conversion layer, the photoelectric conversion layer including silicon; and

an amplifier circuit including a thin film transistor, the thin film transistor including an oxide semiconductor containing indium, gallium, and zinc.

2. A photosensor comprising:

a photoelectric conversion element including a photoelectric conversion layer, the photoelectric conversion layer comprising;

a first semiconductor layer including an impurity element having one conductivity type;

a second semiconductor layer in contact with the first semiconductor layer; and

a third semiconductor layer in contact with the second semiconductor layer, wherein the third semiconductor layer includes an impurity element having a conductivity type opposite to the conductivity type of the first semiconductor layer; and

an amplifier circuit including at least a selection thin film transistor, an amplifying thin film transistor, and a reset thin film transistor,

wherein the selection thin film transistor, the amplifying thin film transistor, and the reset thin film transistor each include an oxide semiconductor containing indium, gallium, and zinc,

wherein a gate electrode of the reset thin film transistor is electrically connectable to a reset gate signal line,

wherein one of a source electrode and a drain electrode of the reset thin film transistor is electrically connectable to a sensor power supply line,

wherein the other one of the source electrode and the drain electrode of the reset thin film transistor is electrically connectable to a gate electrode of the amplifying thin film transistor and one of an anode and a cathode of the photoelectric conversion element,

wherein one of a source electrode and a drain electrode of the amplifying thin film transistor is electrically connectable to the sensor power supply line,

wherein one of a source electrode and a drain electrode of the selection thin film transistor is electrically connectable to a sensor output wiring,

wherein the other one of the source electrode and the drain electrode of the selection thin film transistor is electrically connectable to the other one of the source electrode and the drain electrode of the amplifying thin film transistor, and

wherein a gate electrode of the selection thin film transistor is electrically connectable to a sensor gate signal line.

3. The photosensor according to claim 2,

wherein the reset thin film transistor and the selection thin film transistor are turned on or off according to signals input to the reset gate signal line and the sensor gate signal line.

4. An area sensor comprising:

a plurality of pixels, each of the plurality of pixels comprising;

a photoelectric conversion element including a photoelectric conversion layer, the photoelectric conversion layer including silicon; and

an amplifier circuit including a thin film transistor, the thin film transistor including an oxide semiconductor containing indium, gallium, and zinc.

5. An area sensor comprising:

a plurality of pixels, each of the plurality of pixels comprising;

a photoelectric conversion element including a photoelectric conversion layer, the photoelectric conversion layer comprising;

a first semiconductor layer including an impurity element having one conductivity type;

a second semiconductor layer in contact with the first semiconductor layer; and

a third semiconductor layer in contact with the second semiconductor layer, wherein the third semiconductor layer includes an impurity element having a conductivity type opposite to the conductivity type of the first semiconductor layer; and

an amplifier circuit including at least a selection thin film transistor, an amplifying thin film transistor, and a reset thin film transistor,

wherein the selection thin film transistor, the amplifying thin film transistor, and the reset thin film transistor each include an oxide semiconductor containing indium, gallium, and zinc,

wherein a gate electrode of the reset thin film transistor is electrically connectable to a reset gate signal line,

wherein one of a source electrode and a drain electrode of the reset thin film transistor is electrically connectable to a sensor power supply line,

wherein the other one of the source electrode and the drain electrode of the reset thin film transistor is electrically connectable to a gate electrode of the amplifying thin film transistor and one of an anode and a cathode of the photoelectric conversion element,

wherein one of a source electrode and a drain electrode of the amplifying thin film transistor is electrically connectable to the sensor power supply line,

wherein one of a source electrode and a drain electrode of the selection thin film transistor is electrically connectable to a sensor output wiring,

wherein the other one of the source electrode and the drain electrode of the selection thin film transistor is electrically connectable to the other one of the source electrode and the drain electrode of the amplifying thin film transistor, and

wherein a gate electrode of the selection thin film transistor is electrically connectable to a sensor gate signal line.

6. The area sensor according to claim 5,

wherein the reset thin film transistor and the selection thin film transistor are turned on or off according to signals input to the reset gate signal line and the sensor gate signal line.

7. A display device comprising:

a plurality of pixels, each of the plurality of pixels comprising;

a photoelectric conversion element including a photoelectric conversion layer, the photoelectric conversion layer including silicon;

an amplifier circuit;

a display element; and

a driver circuit of the display element,

wherein the amplifier circuit and the driver circuit each include a thin film transistor, and

wherein the thin film transistor includes an oxide semiconductor containing indium, gallium, and zinc.

8. The display device according to claim 7,

wherein the display element includes an anode, a cathode, and a layer containing a light-emitting substance between the anode and the cathode.

9. The display device according to claim 7,

further comprising a pixel electrode, a counter electrode, and a layer containing liquid crystal between the pixel electrode and the counter electrode.

10. A method for operating the display device according to claim 7 with a laser pointer.

11. A display device comprising:

a plurality of pixels, each of the plurality of pixels comprising;

a photoelectric conversion element including a photoelectric conversion layer, the photoelectric conversion layer comprising;

a first semiconductor layer including an impurity element having one conductivity type;

a second semiconductor layer in contact with the first semiconductor layer; and

a third semiconductor layer in contact with the second semiconductor layer, wherein the third semiconductor layer includes an impurity element having a conductivity type opposite to the conductivity type of the first semiconductor layer;

an amplifier circuit including at least a selection thin film transistor, an amplifying thin film transistor, and a reset thin film transistor;

wherein the selection thin film transistor, the amplifying thin film transistor, and the reset thin film transistor each include an oxide semiconductor containing indium, gallium, and zinc,

wherein a gate electrode of the reset thin film transistor is electrically connectable to a reset gate signal line,

wherein one of a source electrode and a drain electrode of the reset thin film transistor is electrically connectable to a sensor power supply line,

wherein the other one of the source electrode and the drain electrode of the reset thin film transistor is electrically connectable to a gate electrode of the amplifying thin film transistor and one of an anode and a cathode of the photoelectric conversion element,

wherein one of a source electrode and a drain electrode of the amplifying thin film transistor is electrically connectable to the sensor power supply line,

wherein one of a source electrode and a drain electrode of the selection thin film transistor is electrically connectable to a sensor output wiring,

wherein the other one of the source electrode and the drain electrode of the selection thin film transistor is electrically connectable to the other one of the source electrode and the drain electrode of the amplifying thin film transistor, and

wherein a gate electrode of the selection thin film transistor is electrically connectable to a sensor gate signal line,

a display element; and

a driver circuit of the display element including at least a switching thin film transistor including an oxide semiconductor containing indium, gallium, and zinc,

wherein a gate electrode of the switching thin film transistor is electrically connectable to a gate signal line, and

wherein one of a source electrode and a drain electrode of the switching thin film transistor is electrically connectable to a source signal line.

12. The display device according to claim 11,

wherein the display element includes an anode, a cathode, and a layer containing a light-emitting substance between the anode and the cathode.

13. The display device according to claim 11,

further comprising a pixel electrode, a counter electrode, and a layer containing liquid crystal between the pixel electrode and the counter electrode.

14. A method for operating the display device according to claim 11 with a laser pointer.