Display device and electronic device

• US 10,700,098 B2
• Filed: 07/30/2019
• Issued: 06/30/2020
• Est. Priority Date: 08/03/2016
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Takahashi, Kei, Miyake, Hiroyuki
• Primary Examiner(s): Yushin, Nikolay K
• Application Number:
  US16/525,846
• Publication Number:
  US 20190355760A1
• Time in Patent Office: 336 Days
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/0291 Details of output amplifiers or buffers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2330/023 using energy recovery or conservation
• CPC Class Codes: G09G 2354/00 Aspects of interface with display user
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes
• CPC Class Codes: G11C 19/28 using semiconductor elements G11C19/14, G11C19/36 take precedence
• CPC Class Codes: H01L 27/1222 with a particular composition, shape or crystalline structure of the active layer
• 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 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/1262 with a particular formation, treatment or coating of the substrate

Abstract

A display device including a display portion with an extremely high resolution is provided. The display device includes a pixel circuit and a light-emitting element. The pixel circuit includes a first element layer including a first transistor and a second element layer including a second transistor. A channel formation region of the first transistor includes silicon. The first transistor has a function of driving the light-emitting element. The second transistor functions as a switch. A channel formation region of the second transistor includes a metal oxide. The metal oxide functions as a semiconductor. The second element layer is provided over the first element layer.

Claims

1. A display device comprising:

a pixel circuit including a first element layer comprising a first transistor and a second element layer comprising a second transistor; and

a light-emitting element including a first conductive layer, an Electro-Luminescent (EL) layer over the first conductive layer, and a second conductive layer over the EL layer,

wherein a channel formation region of the first transistor comprises silicon,

wherein a channel formation region of the second transistor comprises a metal oxide containing indium (In), gallium (Ga), and zinc (Zn),

wherein the first transistor has a function of driving the light-emitting element,

wherein the second transistor has a function of operating as a switch for supplying voltage to a gate of the first transistor,

wherein the second element layer is provided over the first element layer,

wherein an insulating layer is provided on and in contact with an end portion of the first conductive layer, and

wherein the EL layer is overlapping with the channel formation region of the first transistor, the channel formation region of the second transistor, and the insulating layer.

2. The display device according to claim 1,

wherein the second element layer further comprises a capacitor including a terminal electrically connected to the gate of the first transistor.

3. The display device according to claim 1,

wherein the second element layer further comprises a third transistor having a function of operating as a switch for monitoring an amount of current flowing through the first transistor.

4. The display device according to claim 1,

wherein the first transistor has a double-gate structure.

5. An electronic device comprising:

the display device according to claim 1;

a lens;

an operation button; and

a fixing member.

6. A display device comprising:

a pixel circuit including a first element layer comprising a first transistor and a second element layer comprising a second transistor; and

a light-emitting element including a first conductive layer, an Electro-Luminescent (EL) layer over the first conductive layer, and a second conductive layer over the EL layer,

wherein a channel formation region of the first transistor comprises silicon,

wherein a channel formation region of the second transistor comprises a metal oxide containing indium (In), gallium (Ga), and zinc (Zn),

wherein the first transistor has a function of driving the light-emitting element,

wherein the second transistor has a function of operating as a switch for supplying voltage to a gate of the first transistor,

wherein the second element layer is provided over the first element layer,

wherein the light-emitting element is provided over the second element layer,

wherein an insulating layer is provided on and in contact with an end portion of the first conductive layer, and

wherein the EL layer is overlapping with the channel formation region of the first transistor, the channel formation region of the second transistor, and the insulating layer.

7. The display device according to claim 6,

wherein the second element layer further comprises a capacitor including a terminal electrically connected to the gate of the first transistor.

8. The display device according to claim 6,

wherein the second element layer further comprises a third transistor having a function of operating as a switch for monitoring an amount of current flowing through the first transistor.

9. The display device according to claim 6,

wherein the first transistor has a double-gate structure.

10. An electronic device comprising:

the display device according to claim 6;

a lens;

an operation button; and

a fixing member.

11. A display device comprising:

a pixel circuit including a first element layer comprising a first transistor and a second element layer comprising a second transistor;

a light-emitting element including a first conductive layer, an Electro-Luminescent (EL) layer over the first conductive layer, and a second conductive layer over the EL layer; and

a driver circuit comprising a fourth transistor,

wherein a channel formation region of each of the first transistor and the fourth transistor comprises silicon,

wherein a channel formation region of the second transistor comprises a metal oxide containing indium (In), gallium (Ga), and zinc (Zn),

wherein the first transistor has a function of driving the light-emitting element,

wherein the second transistor has a function of operating as a switch for supplying voltage to a gate of the first transistor,

wherein the second element layer is provided over the first element layer,

wherein an insulating layer is provided on and in contact with an end portion of the first conductive layer, and

wherein the EL layer is overlapping with the channel formation region of each of the first transistor and the fourth transistor, the channel formation region of the second transistor, and the insulating layer.

12. The display device according to claim 11,

wherein the second element layer further comprises a capacitor including a terminal electrically connected to the gate of the first transistor.

13. The display device according to claim 11,

wherein the second element layer further comprises a third transistor having a function of operating as a switch for monitoring an amount of current flowing through the first transistor.

14. The display device according to claim 11,

wherein the first transistor has a double-gate structure.

15. An electronic device comprising:

the display device according to claim 11;

a lens;

an operation button; and

a fixing member.

16. A display device comprising:

a pixel circuit including a first element layer comprising a first transistor and a second element layer comprising a second transistor;

a light-emitting element including a first conductive layer, an Electro-Luminescent (EL) layer over the first conductive layer, and a second conductive layer over the layer; and

a driver circuit comprising a fourth transistor,

wherein a channel formation region of each of the first transistor and the fourth transistor comprises silicon,

wherein a channel formation region of the second transistor comprises a metal oxide containing indium (In), gallium (Ga), and zinc (Zn),

wherein the first transistor has a function of driving the light-emitting element,

wherein the second transistor has a function of operating as a switch for supplying voltage to a gate of the first transistor,

wherein the second element layer is provided over the first element layer,

wherein the light-emitting element is provided over the second element layer,

wherein an insulating layer is provided on and in contact with an end portion of the first conductive layer, and

wherein the EL layer is overlapping with the channel formation region of each of the first transistor and the fourth transistor, the channel formation region of the second transistor, and the insulating layer.

17. The display device according to claim 16,

wherein the second element layer further comprises a capacitor including a terminal electrically connected to the gate of the first transistor.

18. The display device according to claim 16,

wherein the second element layer further comprises a third transistor having a function of operating as a switch for monitoring an amount of current flowing through the first transistor.

19. The display device according to claim 16,

wherein the first transistor has a double-gate structure.

20. An electronic device comprising:

the display device according to claim 16;

a lens;

an operation button; and

a fixing member.

21. A display device comprising:

a pixel circuit comprising;

a first transistor comprising a first gate electrode and a first gate insulating layer in direct contact with the first gate electrode;

a second transistor comprising a second gate electrode and a second gate insulating layer in direct contact with the second gate electrode; and

a capacitor electrically connected to the first transistor and the second transistor;

a first insulating layer over the second transistor;

a light-emitting element comprising a first conductive layer over the first insulating layer, an Electro-Luminescent (EL) layer over the first conductive layer, and a second conductive layer over the EL layer;

a second insulating layer over and in direct contact with an end portion of the first conductive layer; and

a driver circuit comprising a third transistor,

wherein a channel formation region of each of the first transistor and the third transistor comprises silicon,

wherein a channel formation region of the second transistor comprises a metal oxide containing indium (In), gallium (Ga), and zinc (Zn),

wherein the first transistor has a function of driving the light-emitting element,

wherein the second transistor has a function of operating as a switch for supplying voltage to the first gate electrode of the first transistor,

wherein the first gate electrode of the first transistor, one of a source and a drain of the second transistor, and a terminal of the capacitor are directly connected to one another,

wherein the second gate insulating layer is provided over the first gate insulating layer, and

wherein the first conductive layer is overlapping with the first gate electrode and the first gate insulating layer.

22. The display device according to claim 21, further comprising a fourth transistor having a function of operating as a switch for monitoring an amount of current flowing through the first transistor.

23. The display device according to claim 21, wherein the first transistor has a double-gate structure.

24. An electronic device comprising:

the display device according to claim 21;

a lens;

an operation button; and

a fixing member.