Electronic device and method of driving electronic device

• US 20010022565A1
• Filed: 03/05/2001
• Published: 09/20/2001
• Est. Priority Date: 03/10/2000
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime
• Granted Patent: US 7,129,918 B2
• Time in Patent Office: Days
• US Class Current: 345/82
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/0205 Simultaneous scanning of several lines in flat panels
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes

Abstract

Problems such as insufficient brightness, caused by a reduction in duty ratio (the ratio of a light emitting period and a non-light emitting period), are improved upon in accordance with using a novel method of driving and a novel circuit in an electronic device. Signals are written into pixels of a plurality of differing lines during one gate signal line selection period. By arbitrarily setting, to a certain extent, the time from when a signal is input into the pixels of a certain line until the next signal is input to the same pixels, while ensuring the time for writing into the pixels, a sustain (turn on) period can be arbitrarily set and a high duty ratio is realized.

Claims

1. A method of driving an electronic device having n-bit grey scale comprising a step of:

controlling a length of a turn on period of each of self light emitting elements,

wherein;

one frame period is divided into n subframe periods SF₁, SF₂, . . . SF_n;

said n subframe periods have address periods Ta₁, Ta₂, . . . , Ta_n and sustain periods Ts₁, Ts₂, . . . , Ts_n, respectively;

the length of said sustain periods Ts₁;

;

Ts₂;

;

. . . ;

;

Ts_n=2<sup>(n−

1)</sup>;

;

2<sup>(n−

2)</sup>;

;

2⁰; and

at least one of said n subframe periods has such a period that one of said address periods and one of said sustain periods overlap.

10. The method of driving an electronic device according to

claim 1

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.

2. A method of driving an electronic device having n-bit grey scale comprising a step of:

controlling a length of a turn on period of each of self light emitting elements,

wherein;

one frame period is divided into n subframe periods SF₁, SF₂, . . . , SF_n;

said n subframe periods have address periods Ta₁, Ta₂, . . . , Ta_n and sustain periods Ts₁, Ts₂, . . . , Ts_n,respectively;

the length of said sustain periods Ts₁;

;

Ts₂;

;

. . . ;

;

Ts_n=2<sup>(n−

1)</sup>;

;

2<sup>(n−

2)</sup>;

;

. . . ;

;

2⁰;

a plurality of gate signal line selection periods within each of said n subframe periods, each of said plurality of gate signal lines has m sub-gate signal line selection periods;

at most one of said plurality of gate signal line is selected within each of said m sub-gate signal line selection periods; and

at most (m×

n)-th times of vertical scanning are performed in said one frame period.

11. The method of driving an electronic device according to

claim 2

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.

3. A method of driving an electronic device having n-bit grey scale comprising a step of:

controlling a length of a turn on period of each of self light emitting elements,

wherein;

one frame period is divided into n subframe periods SF₁, SF₂, . . . , SF_n;

said n subframe periods have address periods Ta₁, Ta₂, . . . , Ta_n and sustain periods Ts₁, Ts₂, . . . , Ts_n,respectively;

the length of said sustain periods Ts₁;

;

Ts₂;

;

. . . ;

;

Ts_n=2<sup>(n−

1)</sup>;

;

2<sup>(n−

2)</sup>;

;

. . . ;

;

2⁰;

a plurality of gate signal line selection periods within each of said n subframe periods, each of said plurality of gate signal lines has m sub-gate signal line selection periods;

at most one of said plurality of gate signal line is selected within each of said m sub-gate signal line selection periods; and

at most m gate signal lines, are different from one another, are selected within each of said plurality of gate signal line selection periods.

12. The method of driving an electronic device according to

claim 3

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.

4. A method of driving an electronic device having n-bit grey scale comprising a step of:

controlling a length of a turn on period of each of self light emitting elements,

wherein;

one frame period is divided into n subframe periods SF₁, SF₂, . . . , SF_n;

said n subframe periods have address periods Ta₁, Ta₂, . . . , Ta_n and sustain periods Ts₁, Ts₂, . . . , Ts_n, respectively;

the length of said sustain periods Ts₁;

;

Ts₂;

;

. . . ;

;

Ts_n=2<sup>(n−

1)</sup>;

;

2<sup>(n−

2)</sup>;

;

. . . ;

;

2⁰;

a plurality of gate signal line selection periods within each of said n subframe periods, each of said plurality of gate signal lines has m sub-gate signal line selection periods;

at most one of said plurality of gate signal line is selected within each of said m sub-gate signal line selection periods;

at most m gate signal lines, are different from one another, are selected within each of said plurality of gate signal line selection periods;

reset signal is inputted within such a period that an address period within one of said n subframe periods and an address period within another one of said n subframe periods overlap; and

said self light emitting elements are in turn off state within such a period that said reset signal is inputted.

13. The method of driving an electronic device according to

claim 4

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.

5. An electronic device comprising:

a source signal line driver circuit;

a gate signal line driver circuit; and

a pixel portion having a plurality of self light emitting elements arranged in a matrix shape;

wherein;

n-bit grey scale control for controlling the length of a turn on period of the self light emitting elements is performed;

one frame period has n subframe periods SF₁, SF₂, . . . , SF_n;

the n subframe periods SF₁, SF₂, . . . , SF_n, have;

address (write in) periods Ta₁, Ta₂, . . . , Ta_n, respectively; and

sustain (turn on) periods Ts₁, Ts₂, . . . , Ts_n, respectively;

the length of the sustain (turn on) periods Ts₁;

;

Ts₂;

;

. . . ;

;

Ts_n=2<sup>(n−

1)</sup>;

;

2<sup>(n−

2)</sup>;

;

. . . ;

;

2⁰; and

at least one of said n subframe periods has such a period that one of said address periods and one of said sustain periods overlap.

14. An electronic device according to

claim 5

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.

6. An electronic device comprising:

a source signal line driver circuit;

a gate signal line driver circuit; and

a pixel portion having a plurality of self light emitting elements arranged in a matrix shape;

wherein;

n-bit grey scale control for controlling the length of a turn on period of the self light emitting elements is performed;

one frame period has n subframe periods SF₁, SF₂, . . . , SF_n;

the n subframe periods SF₁, SF₂, . . . , SF_n have;

address (write in) periods Ta₁, Ta₂, . . . , Ta_n, respectively; and

sustain (turn on) periods Ts₁, Ts₂, . . . , Ts_n, respectively;

the length of the sustain (turn on) periods Ts₁;

;

Ts₂;

;

. . . ;

;

Ts_n=2<sup>(n−

1)</sup>;

;

2<sup>(n−

2)</sup>;

;

. . . ;

;

2⁰; and

a plurality of gate signal line selection periods within each of said n subframe periods, each of said plurality of gate signal lines has m sub-gate signal line selection periods;

at most one of said plurality of gate signal line is selected within each of said m sub-gate signal line selection periods; and

at most (m×

n)-th times of vertical scanning are performed in said one frame period.

15. An electronic device according to

claim 6

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.

7. An electronic device comprising:

a source signal line driver circuit;

a gate signal line driver circuit; and

a pixel portion having a plurality of self light emitting elements arranged in a matrix shape;

wherein;

one frame period has n subframe periods SF₁, SF₂, . . . , SF_n;

the n subframe periods SF₁, SF₂, . . . , SF_n have;

address (write in) periods Ta₁, Ta₂, . . . , Ta_n, respectively; and

sustain (turn on) periods Ts₁, Ts₂, . . . , Ts_n, respectively;

the length of the sustain (turn on) periods Ts₁;

;

Ts₂;

;

. . . ;

;

Ts_n=2<sup>(n−

1)</sup>;

;

2<sup>(n−

2)</sup>;

;

. . . ;

;

2⁰;

a plurality of gate signal line selection periods within each of said n subframe periods, each of said plurality of gate signal lines has m sub-gate signal line selection periods;

at most one of said plurality of gate signal line is selected within each of said m sub-gate signal line selection periods; and

at most m gate signal lines, are different from one another, are selected within each of said plurality of gate signal line selection periods.

16. An electronic device according to

claim 7

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.

8. An electronic device comprising:

a source signal line driver circuit;

a gate signal line driver circuit; and

a pixel portion having a plurality of self light emitting elements arranged in a matrix shape;

wherein;

one frame period has n subframe periods SF₁, SF₂, . . . , SF_n;

the n subframe periods SF₁, SF₂, . . . , SF_n have;

address (write in) periods Ta₁, Ta₂, . . . , Ta_n, respectively; and

sustain (turn on) periods Ts₁, Ts₂, . . . , Ts_n, respectively;

the length of the sustain (turn on) periods Ts₁;

;

Ts₂;

;

. . . ;

;

Ts_n=2<sup>(n−

1)</sup>;

;

2<sup>(n−

2)</sup>;

;

. . . ;

;

2⁰; and

a plurality of gate signal line selection periods within each of said n subframe periods, each of said plurality of gate signal lines has m sub-gate signal line selection periods;

at most one of said plurality of gate signal line is selected within each of said m sub-gate signal line selection periods;

at most m gate signal lines, are different from one another, are selected within each of said plurality of gate signal line selection periods;

reset signal is inputted within such a period that an address period within one of said n subframe periods and an address period within another one of said n subframe periods overlap; and

said self light emitting elements are in turn off state within such a period that said reset signal is inputted.

17. An electronic device according to

claim 8

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.

9. An electronic device comprising:

a source signal line driver circuit;

a gate signal line driver circuit; and

a pixel portion in which a plurality of self light emitting elements are arranged in an matrix shape having a rows and b columns;

wherein;

the source signal driver circuit uses a plurality of source driver circuits having;

at least one first shift register circuit;

a first memory circuit for storing a digital image signal; and

a second memory circuit for storing an output signal of the first memory circuit;

the gate signal line driver circuit uses a plurality of gate driver circuits having;

at least one second shift register circuit; and

at least one buffer circuit;

one frame period has n subframe periods SF₁, SF₂, . . . , SF_n;

a plurality of gate signal line selection periods within the subframe periods has m sub-gate signal line selection periods;

write in to at most one gate signal line is performed in the sub-gate signal line selection periods;

write in of signals to at most m gate signal lines is completed within one gate signal line selection period;

one source signal line is electrically connected to a maximum of m source driver circuits, through a first switching circuit;

one gate signal line is electrically connected to a maximum of m gate driver circuits, through a second switching circuit;

the source signal line driver circuit has a maximum of b×

m source driver circuits;

the gate signal line driver circuit has a maximum of a×

m gate driver circuits;

the first switching circuit selects only one electrically connected source driver circuit, from among the m source driver circuits, during one dot data write in period, connects to the source signal line, and performs signal write in; and

the second switching circuit selects only one electrically connected gate driver circuit, from among the m gate driver circuits, during one sub-gate signal line selection period, connects to the gate signal line, and performs write in.

18. An electronic device according to

claim 9

, wherein said electronic device is a device selected from the group consisting of:

an OLED display, a video camera, head mounted display a DVD player, a personal computer, a portable telephone and a car audio.