Display system and electrical appliance

• US 10,467,961 B2
• Filed: 01/03/2019
• Issued: 11/05/2019
• Est. Priority Date: 01/17/2000
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Koyama, Jun, Ishimaru, Noriko
• Primary Examiner(s): Faragalla, Michael A
• Application Number:
  US16/238,633
• Publication Number:
  US 20190156742A1
• Time in Patent Office: 306 Days
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 2354/00 Aspects of interface with display user
• CPC Class Codes: G09G 2360/14 Detecting light within display terminals, e.g. using a single or a plurality of photosensors
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/30 using electroluminescent panels
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

A display system in which the luminance of light-emitting elements in a light-emitting device is adjusted based on information on an environment. A sensor obtains information on an environment as an electrical signal. A CPU converts, based on comparison data set in advance, the information signal into a correction signal for correcting the luminance of EL elements. Upon receiving this correction signal, a voltage changer applies a predetermined corrected potential to the EL elements. Thus, this display system enables control of the luminance of the EL elements.

Claims

1. A display device comprising a pixel portion, the pixel portion comprising:

a polycrystalline semiconductor layer comprising a channel formation region of a transistor;

a first conductive layer comprising a region functioning as a gate electrode of the transistor;

a second conductive layer electrically connected to the polycrystalline semiconductor layer;

an insulating layer over the second conductive layer, the insulating layer comprising a contact hole;

a third conductive layer over the insulating layer, the third conductive layer electrically connected to the second conductive layer through the contact hole;

a first organic resin over the contact hole and the third conductive layer;

an EL layer over the third conductive layer and the first organic resin; and

a fourth conductive layer over the EL layer,

wherein the pixel portion is over a substrate,

wherein the insulating layer comprises a second organic resin,

wherein the first conductive layer comprises molybdenum,

wherein the second conductive layer comprises;

a first titanium film;

an aluminum film over the first titanium film; and

a second titanium film,

wherein the third conductive layer comprises indium oxide and tin oxide,

wherein the fourth conductive layer comprises magnesium,

wherein the contact hole is filled with the third conductive layer and the first organic resin,

wherein a top surface of the first organic resin comprises a region higher than a top surface of the third conductive layer, and

wherein the first conductive layer comprises a regin overlapping with the channel formation region and not overlapping with the first organic resin.

2. The display device according to claim 1, wherein a thickness of the insulating layer is higher than or equal to 0.5 μ

m and lower than or equal to 5 μ

m.

3. The display device according to claim 1, further comprising;

a first gate signal driver circuit over the substrate; and

a second gate signal driver circuit over the substrate,

wherein the pixel portion is arranged between the first gate signal driver circuit and the second gate signal driver circuit.

4. The display device according to claim 1,

wherein the pixel portion further comprises a capacitor,

wherein a first electrode of the capacitor is electrically connected to the gate electrode of the transistor, and

wherein a second electrode of the capacitor is electrically connected to a power supply line.

5. A portable information terminal comprising the display device according to claim 1, wherein the pixel portion is configured to display white-colored characters on a black-colored background.

6. A portable information terminal comprising the display device according to claim 1,

wherein the pixel portion is surrounded by a housing material, and

wherein the housing material comprises glass.

7. An electrical appliance comprising a pixel portion, the pixel portion comprising:

a polycrystalline semiconductor layer comprising a channel formation region of a transistor;

a first conductive layer comprising a region functioning as a gate electrode of the transistor;

a second conductive layer electrically connected to the polycrystalline semiconductor layer;

an insulating layer over the second conductive layer, the insulating layer comprising a contact hole;

a third conductive layer over the insulating layer, the third conductive layer electrically connected to the second conductive layer through the contact hole;

a first organic resin over the contact hole and the third conductive layer;

an EL layer over the third conductive layer and the first organic resin; and

a fourth conductive layer over the EL layer,

wherein the contact hole is filled with the third conductive layer and the first organic resin,

wherein a top surface of the first organic resin comprises a region higher than a top surface of the third conductive layer,

wherein the first conductive layer comprises a region overlapping with the channel formation region and not overlapping with the first organic resin,

wherein the electrical appliance further comprises a sensor, and

wherein the electrical appliance is capable of control brightness of the pixel portion based on an amount of light which is received by the sensor.

8. The electrical appliance according to claim 7, wherein a thickness of the insulating layer is higher than or equal to 0.5 μ

m and lower than or equal to 5 μ

m.

9. The electrical appliance according to claim 7,

wherein the pixel portion is over a substrate,

wherein the electrical appliance further comprises:

a first gate signal driver circuit over the substrate; and

a second gate signal driver circuit over the substrate, and

wherein the pixel portion is arranged between the first gate signal driver circuit and the second gate signal driver circuit.

10. The electrical appliance according to claim 7,

wherein the pixel portion further comprises a capacitor,

wherein a first electrode of the capacitor is electrically connected to the gate electrode of the transistor, and

wherein a second electrode of the capacitor is electrically connected to a power supply line.

11. An electrical appliance comprising a pixel portion, the pixel portion comprising:

a polycrystalline semiconductor layer comprising a channel formation region of a transistor;

a first conductive layer comprising a region functioning as a gate electrode of the transistor;

a second conductive layer electrically connected to the polycrystalline semiconductor layer;

an insulating layer over the second conductive layer, the insulating layer comprising a contact hole;

a third conductive layer over the insulating layer, the third conductive layer electrically connected to the second conductive layer through the contact hole;

a first organic resin over the contact hole and the third conductive layer;

an EL layer over the third conductive layer and the first organic resin; and

a fourth conductive layer over the EL layer,

wherein the insulating layer comprises a second organic resin,

wherein the first conductive layer comprises molybdenum,

wherein the second conductive layer comprises;

a first titanium film;

an aluminum film over the first titanium film; and

a second titanium film,

wherein the third conductive layer comprises indium oxide and tin oxide,

wherein the fourth conductive layer comprises magnesium,

wherein the contact hole is filled with the third conductive layer and the first organic resin,

wherein a top surface of the first organic resin comprises a region higher than a top surface of the third conductive layer,

wherein the first conductive layer comprises a region overlapping with the channel formation region and not overlapping with the first organic resin,

wherein the electrical appliance further comprises a sensor, and

wherein the electrical appliance is capable of control brightness of the pixel portion based on an amount of light which is received by the sensor.

12. The electrical appliance according to claim 11, wherein a thickness of the insulating layer is higher than or equal to 0.5 μ

m and lower than or equal to 5 μ

m.

13. The electrical appliance according to claim 11,

wherein the pixel portion is over a substrate,

wherein the electrical appliance further comprises:

a first gate signal driver circuit over the substrate; and

a second gate signal driver circuit over the substrate, and

wherein the pixel portion is arranged between the first gate signal driver circuit and the second gate signal driver circuit.

14. The electrical appliance according to claim 11,

wherein the pixel portion further comprises a capacitor,

wherein a first electrode of the capacitor is electrically connected to the gate electrode of the transistor, and

wherein a second electrode of the capacitor is electrically connected to a power supply line.