Display device and electronic device

• US 9,257,082 B2
• Filed: 08/31/2010
• Issued: 02/09/2016
• Est. Priority Date: 09/04/2009
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime, Akimoto, Kengo, Tsubuku, Masashi, Sasaki, Toshinari
• Primary Examiner(s): Johnson, Gerald
• Assistant Examiner(s): KOHLMAN, CHRISTOPHER J
• Application Number:
  US12/872,861
• Publication Number:
  US 20110057918A1
• Time in Patent Office: 1,988 Days
• Field of Search: 345/204, 345/215
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• 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 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

A display device including a pixel having a memory. The pixel includes at least a display element, a capacitor, an inverter, and a switch. The switch is controlled with a signal held in the capacitor and a signal output from the inverter so that voltage is supplied to the display element. The inverter and the switch can be constituted by transistors with the same polarity. A semiconductor layer included in the pixel may be formed using a light-transmitting material. Moreover, a gate electrode, a drain electrode, and a capacitor electrode may be formed using a light-transmitting conductive layer. The pixel is formed using a light-transmitting material in such a manner, whereby the display device can be a transmissive display device while including a pixel having a memory.

Claims

1. A display device comprising:

a display element comprising a pixel electrode;

a first circuit configured to control input of an image signal;

a second circuit configured to hold the image signal; and

a third circuit configured to invert polarity of a voltage supplied to the display element,

wherein the first circuit, the second circuit, and the third circuit each comprises a transistor,

wherein the transistor comprises a gate electrode, a source electrode, a drain electrode, a channel layer, and a wiring,

wherein each of the gate electrode, the source electrode, the drain electrode, and the wiring is formed using a light-transmitting material,

wherein the channel layer comprises an oxide semiconductor, and

wherein the pixel electrode overlaps the first circuit, the second circuit, and the third circuit.

2. The display device according to claim 1, further comprising:

a fourth circuit,

wherein the first circuit, the second circuit, the third circuit and the display element are positioned in a pixel portion,

wherein the fourth circuit is configured to control the pixel portion, and

wherein the fourth circuit is formed using a material different from the light-transmitting material.

3. An electronic device comprising the display device according to claim 1, and an operation switch.

4. The display device according to claim 1, further comprising:

a source signal line;

a gate signal line;

a capacitor line; and

a power supply line,

wherein each of the source signal line, the gate signal line, the capacitor line, and the power supply line is formed using a light-transmitting material.

5. A display device comprising:

a first circuit comprising;

a first transistor;

a second circuit comprising;

a first capacitor;

a second capacitor; and

an inverter comprising an input terminal electrically connected to the first capacitor and an output terminal electrically connected to the second capacitor;

a third circuit comprising;

a second transistor comprising a control terminal electrically connected to the first capacitor; and

a third transistor comprising a control terminal electrically connected to the second capacitor; and

a display element comprising a pixel electrode electrically connected to the second transistor and the third transistor,

wherein an image signal is input to the first capacitor and the second capacitor through the first transistor,

wherein the third circuit is configured to invert polarity of a voltage supplied to the display element,

wherein the first transistor, the second transistor, and the third transistor each comprises a gate electrode, a source electrode, a drain electrode, a channel layer, and a wiring,

wherein each of the gate electrode, the source electrode, the drain electrode, and the wiring is formed using a light-transmitting material,

wherein the channel layer comprises an oxide semiconductor, and

wherein the pixel electrode overlaps the first circuit, the second circuit, and the third circuit.

6. The display device according to claim 5, further comprising:

a first wiring electrically connected to the first capacitor through the first transistor;

a second wiring; and

a third wiring electrically connected to the second wiring through the second transistor and the third transistor,

wherein each of the first wiring, the second wiring, and the third wiring is formed using a light-transmitting material.

7. The display device according to claim 5, further comprising:

a first wiring electrically connected to the first capacitor through the first transistor;

a second wiring; and

a third wiring electrically connected to the second wiring through the second transistor and the third transistor,

wherein the image signal is input to the first wiring, and

wherein each of the first wiring, the second wiring, and the third wiring is formed using a light-transmitting material.

8. The display device according to claim 5,

wherein the pixel electrode, the first capacitor, the second capacitor, and the inverter each comprises a light-transmitting layer, and

wherein the pixel electrode is provided above the first transistor, the second transistor, the third transistor, the first capacitor, the second capacitor, and the inverter.

9. The display device according claim 5, further comprising:

a fourth circuit electrically connected to the first circuit,

wherein the pixel electrode, the first capacitor, the second capacitor, and the inverter each comprises a light-transmitting layer, and

wherein the fourth circuit comprise a layer different from the light-transmitting layer.

10. An electronic device comprising the display device according to claim 5, and an operation switch.

11. The display device according to claim 5, further comprising:

a source signal line;

a gate signal line;

a capacitor line; and

a power supply line,

wherein each of the source signal line, the gate signal line, the capacitor line, and the power supply line is formed using a light-transmitting material.