DISPLAY DEVICE

• US 20170176791A1
• Filed: 12/12/2016
• Published: 06/22/2017
• Est. Priority Date: 12/18/2015
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YOSHIZUMI, Kensuke, KUBOTA, Daisuke, KUSUNOKI, Koji
• Granted Patent: US 10,114,263 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/13685 Top gates
• CPC Class Codes: G02F 2201/121 common or background
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO

Abstract

A liquid crystal display device includes a transmissive region and a reflective region. The liquid crystal display device includes a liquid crystal element, a transistor, a scan line, a signal line, and an insulating layer. A semiconductor layer of the transistor includes a channel region and a low-resistance region. A channel region overlaps with a gate with a gate insulating layer provided therebetween. The low-resistance region includes a first portion in contact with a pixel electrode of the liquid crystal element and a second portion in contact with a side surface of an opening portion in the insulating layer. The first portion of the low-resistance region is positioned in the transmissive region or the reflective region. The reflective region includes a layer that reflects visible light. The layer that reflects visible light includes a portion positioned between the scan line or the signal line and a liquid crystal layer.

Claims

1. A display device including a transmissive region and a reflective region, comprising:

a liquid crystal element;

a transistor;

a scan line;

a signal line;

a layer that reflects visible light; and

a first insulating layer,

wherein;

the liquid crystal element includes a pixel electrode, a common electrode, and a liquid crystal layer,

the transistor includes a semiconductor layer, a gate, and a gate insulating layer,

the first insulating layer is provided between the pixel electrode and the transistor,

the first insulating layer includes an opening portion,

the pixel electrode is provided between the liquid crystal layer and the first insulating layer,

the common electrode is configured to transmit visible light,

the semiconductor layer includes a first region and a second region,

the first region overlaps the gate with the gate insulating layer therebetween,

the second region includes a first portion in contact with the pixel electrode and a second portion in contact with a side surface of the opening portion in the first insulating layer,

the second region has resistivity lower than resistivity of the first region,

the first portion is provided in at least one of the transmissive region and the reflective region,

the reflective region includes the layer that reflects visible light, and

the layer that reflects visible light includes a portion between the liquid crystal layer and at least one of the scan line and the signal line.

2. The display device according to claim 1,

wherein:

the semiconductor layer is a silicon semiconductor layer, and

the first portion of the silicon semiconductor layer is provided in the reflective region.

3. The display device according to claim 1, further comprising a coloring layer,

wherein:

the coloring layer overlaps the pixel electrode with the liquid crystal layer therebetween, and

a thickness of the coloring layer in the reflective region is greater than or equal to 40% and less than or equal to 60% of a thickness of the coloring layer in the transmissive region.

4. The display device according to claim 1,

wherein a thickness of the liquid crystal layer in the reflective region is greater than or equal to 40% and less than or equal to 60% of a thickness of the liquid crystal layer in the transmissive region.

5. The display device according to claim 1, further comprising a light-blocking layer,

wherein the light-blocking layer is provided at a boundary between the transmissive region and the reflective region.

6. The display device according to claim 1,

wherein a surface of the pixel electrode on the liquid crystal layer side and a surface of the first insulating layer on the liquid crystal layer side form a same surface.

7. The display device according to claim 1,

wherein the common electrode is provided between the transistor and the liquid crystal layer.

8. The display device according to claim 7, further comprising a second insulating layer,

wherein:

the second insulating layer is provided between the pixel electrode and the common electrode, and

a surface of the common electrode on the liquid crystal layer side and a surface of the second insulating layer on the liquid crystal layer side form a same surface.

9. The display device according to claim 1,

wherein:

a direction in which the scan line extends intersects with a direction in which the signal line extends, and

a direction in which a plurality of pixels exhibiting a same color are arranged intersects with a direction in which the signal line extends.

10. A module comprising:

the display device according to claim 1; and

at least one of a flexible printed circuit board and an integrated circuit.

11. An electronic device comprising:

the module according to claim 10; and

at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button.

12. A display device including a transmissive region and a reflective region, comprising:

a liquid crystal element;

a transistor;

a scan line;

a signal line;

a layer that reflects visible light; and

a first insulating layer,

wherein;

the liquid crystal element includes a pixel electrode, a common electrode, and a liquid crystal layer,

the transistor includes an oxide semiconductor layer, a gate, and a gate insulating layer,

the first insulating layer is provided between the pixel electrode and the transistor,

the first insulating layer includes an opening portion,

the pixel electrode is provided between the liquid crystal layer and the first insulating layer,

each of the pixel electrode and the common electrode is configured to transmit visible light,

the oxide semiconductor layer includes a first region and a second region,

the first region overlaps the gate with the gate insulating layer therebetween,

the second region includes a first portion in contact with the pixel electrode and a second portion in contact with a side surface of the opening portion in the first insulating layer,

the second region has resistivity lower than resistivity of the first region,

the first portion is provided in the transmissive region,

the reflective region includes the layer that reflects visible light, and

the layer that reflects visible light includes a third portion between the liquid crystal layer and at least one of the scan line and the signal line.

13. The display device according to claim 12,

wherein the pixel electrode and the oxide semiconductor layer include indium, zinc, and at least one of aluminum, gallium, yttrium, and tin.

14. The display device according to claim 12,

wherein the common electrode includes indium, zinc, and at least one of aluminum, gallium, yttrium, and tin.

15. The display device according to claim 12,

wherein the pixel electrode and the oxide semiconductor layer include a crystal part.

16. The display device according to claim 15,

wherein the crystal part included in the pixel electrode and the oxide semiconductor layer has c-axis alignment.

17. The display device according to claim 12,

wherein the common electrode includes a crystal part.

18. The display device according to claim 17,

wherein the crystal part included in the common electrode has c-axis alignment.

19. The display device according to claim 12,

wherein:

the transistor includes a back gate,

the back gate includes a portion overlapping the gate with the oxide semiconductor layer therebetween,

the gate and the back gate are electrically connected to each other, and

the gate includes indium, zinc, and at least one of aluminum, gallium, yttrium, and tin.

20. The display device according to claim 12,

wherein the layer that reflects visible light includes a fourth portion overlapping with the first region.

21. The display device according to claim 12, further comprising a coloring layer,

wherein:

the coloring layer overlaps the pixel electrode with the liquid crystal layer therebetween, and

a thickness of the coloring layer in the reflective region is greater than or equal to 40% and less than or equal to 60% of a thickness of the coloring layer in the transmissive region.

22. The display device according to claim 12,

wherein a thickness of the liquid crystal layer in the reflective region is greater than or equal to 40% and less than or equal to 60% of a thickness of the liquid crystal layer in the transmissive region.

23. The display device according to claim 12, further comprising a light-blocking layer,

wherein the light-blocking layer is provided at a boundary between the transmissive region and the reflective region.

24. The display device according to claim 12,

wherein a surface of the pixel electrode on the liquid crystal layer side and a surface of the first insulating layer on the liquid crystal layer side form a same surface.

25. The display device according to claim 12,

wherein the common electrode is provided between the transistor and the liquid crystal layer.

26. The display device according to claim 25, further comprising a second insulating layer,

wherein:

the second insulating layer is provided between the pixel electrode and the common electrode, and

a surface of the common electrode on the liquid crystal layer side and a surface of the second insulating layer on the liquid crystal layer side form a same surface.

27. The display device according to claim 12,

wherein:

a direction in which the scan line extends intersects with a direction in which the signal line extends, and

a direction in which a plurality of pixels exhibiting a same color are arranged intersects with a direction in which the signal line extends.

28. A module comprising:

the display device according to claim 12; and

at least one of a flexible printed circuit board and an integrated circuit.

29. An electronic device comprising:

the module according to claim 28; and

at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button.