Electro-optical device, method of manufacturing the same, and electronic apparatus

• US 20060066263A1
• Filed: 08/30/2005
• Published: 03/30/2006
• Est. Priority Date: 09/24/2004
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Ryukoku University, Seiko Epson Corporation (Seiko Group)
• Inventors: Hara, Hiroyuki, Kimura, Mutsumi, Okuyama, Tomoyuki
• Application Number:
  US11/213,970
• Publication Number:
  US 20060066263A1
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• 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 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/325 the data current flowing through the driving transistor during a setting phase, e.g. by using a switch for connecting the driving transistor to the data driver
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1266 the substrate on which the devices are formed not being the final device substrate, e.g. using a temporary substrate
• CPC Class Codes: H01L 27/13 combined with thin-film or thick-film passive components
• CPC Class Codes: H05B 45/60 Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED]
• CPC Class Codes: H10K 59/1201 Manufacture or treatment
• CPC Class Codes: H10K 59/1275 Electrical connections of the two substrates
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 71/80 using temporary substrates
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An electro-optical device which has a program period, a light-emitting period, an erasing period, and a lights-off period in one frame and controls the light-emitting period according to a light emission gray-scale level including a driving transistor that includes a current control terminal, a current input terminal, and a current output terminal, and controls a current amplifying ratio on the basis of a voltage between the current control terminal and the current input terminal, an electro-optical element that is supplied with the driving current from the driving transistor to emit light, a storage capacitor that stores the charge corresponding to the voltage between the current control terminal and the current input terminal of the driving transistor, a constant current source that outputs a constant current that is independent of the light emission gray-scale level, a voltage source that outputs a driving stop signal that turns off the driving transistor, a selection transistor that opens/closes a current path connecting any one of the constant current source and the voltage source with the driving transistor, and a scan line that outputs open/close signals that turn on/off the selection transistor. The program period is a period when the selection transistor is turned on by outputting an open signal to the scan line, and when the constant current flows from the constant current source to the driving transistor through the current path, the charge corresponding to the voltage between the current control terminal and the current input terminal is stored in the storage capacitor. The light-emitting period is a period when the selection transistor is turned off by outputting a close signal to the scan line, and the voltage corresponding to the charge stored in the storage capacitor is supplied between the current control terminal and the current input terminal of the driving transistor to supply the driving current to the electro-optical element. The erasing period is a period when the selection transistor is turned on by outputting the open signal to the scan line, and the driving stop signal is supplied to the driving transistor from the voltage source through the current path to turn off the driving transistor so that the electro-optical element stops emitting light. The lights-off period is a period when the selection transistor is turned off by outputting the close signal to the scan line, and the electro-optical element retains a non-light-emitting state. A time constant of the scan line is set so that signal delay of the open/close signals is 10% or less of a theoretical value.

Claims

1. An electro-optical device which has a program period, a light-emitting period, an erasing period, and a lights-off period in one frame and controls the light-emitting period according to a light emission gray-scale level, comprising:

a driving transistor that includes a current control terminal, a current input terminal, and a current output terminal, and controls a current amplifying ratio on the basis of a voltage between the current control terminal and the current input terminal;

an electro-optical element that is supplied with the driving current from the driving transistor to emit light;

a storage capacitor that stores the charge corresponding to the voltage between the current control terminal and the current input terminal of the driving transistor;

a constant current source that outputs a constant current that is independent of the light emission gray-scale level;

a voltage source that outputs a driving stop signal that turns off the driving transistor;

a selection transistor that opens/closes a current path connecting any one of the constant current source and the voltage source with the driving transistor; and

a scan line that outputs open/close signals that turn on/off the selection transistor,

wherein the program period is a period when the selection transistor is turned on by outputting an open signal to the scan line, and when the constant current flows from the constant current source to the driving transistor through the current path, the charge corresponding to the voltage between the current control terminal and the current input terminal is stored in the storage capacitor,

the light-emitting period is a period when the selection transistor is turned off by outputting a close signal to the scan line, and the voltage corresponding to the charge stored in the storage capacitor is supplied between the current control terminal and the current input terminal of the driving transistor to supply the driving current to the electro-optical element,

the erasing period is a period when the selection transistor is turned on by outputting the open signal to the scan line, and the driving stop signal is supplied to the driving transistor from the voltage source through the current path to turn off the driving transistor so that the electro-optical element stops emitting light,

the lights-off period is a period when the selection transistor is turned off by outputting the close signal to the scan line, and a the electro-optical element retains a non-light-emitting state, and

the time constant of the scan line is set so that the signal delay of the open/close signals is 10% or less of a theoretical value.

2. The electro-optical device according to claim 1,

wherein the time constant of the scan line is set by increasing/decreasing a resistance component using a thickness and/or a line width of the scan line as a parameter.

3. The electro-optical device according to claim 1,

wherein the time constant of the scan line is set by increasing/decreasing a resistance component using the specific resistance of a material used for forming the scan line as a parameter.

4. The electro-optical device according to claim 1,

wherein the time constant of the scan line is set by increasing/decreasing a capacitance component using a distance between adjacent scan lines as a parameter.

5. The electro-optical device according to claim 1,

wherein the time constant of the scan line is set by increasing/decreasing a capacitance component using a relative dielectric constant of a material used for forming an insulating film arranged above and/or below the scan line as a parameter.

6. The electro-optical device according to claim 1,

wherein the time constant of the scan line is set by increasing/decreasing a capacitance component using a thickness of a material used for forming an insulating film arranged above and/or below the scan line as a parameter.

12. The electro-optical device according to claim 1,

wherein the time constant of the wiring layer is set by increasing/decreasing a capacitance component using a distance between adjacent first scan lines, adjacent second scan lines, or adjacent data lines as a parameter.

13. The electro-optical device according to claim 1,

wherein the time constant of the wiring layer is set by increasing/decreasing a capacitance component using a relative dielectric constant of a material used for forming an insulating film arranged above and/or below the first scan line, the second scan line, or the data line as a parameter.

14. The electro-optical device according to claim 1,

wherein the time constant of the wiring layer is set by increasing/decreasing a capacitance component using a thickness of a material used for forming an insulating film arranged above and/or below the first scan line, the second scan line, or the data line as a parameter.

15. The electro-optical device according to claim 1,

wherein the electro-optical element is an organic electroluminescent element.

16. An electronic apparatus comprising the electro-optical device according to claim 1.

7. An electro-optical device which has a program period, a light-emitting period, an erasing period, and a lights-off period in one frame and controls the light-emitting period according to a light emission gray-scale level, comprising:

a driving transistor that includes a current control terminal, a current input terminal, and a current output terminal, and controls a current amplifying ratio on the basis of a voltage between the current control terminal and the current input terminal;

an electro-optical element that is supplied with the driving current from the driving transistor to emit light;

a storage capacitor that stores the charge corresponding to the voltage between the current control terminal and the current input terminal of the driving transistor;

a constant current source that outputs a constant current that is independent of the light emission gray-scale level;

a voltage source that outputs a driving stop signal that turns off the driving transistor;

a selection transistor that opens/closes a data line connecting any either the constant current source or the voltage source with the driving transistor; and

a first scan line that outputs open/close signals that turn on/off the selection transistor,

wherein the program period is a period when the selection transistor is turned on by outputting an open signal to the first scan line, and when the constant current flows from the constant current source to the driving transistor through the data line, the charge corresponding to the voltage between the current control terminal and the current input terminal is stored in the storage capacitor,

the light-emitting period is a period when the selection transistor is turned off by outputting a close signal to the first scan line, and the voltage corresponding to the charge stored in the storage capacitor is supplied between the current control terminal and the current input terminal of the driving transistor to supply the driving current to the electro-optical element,

the erasing period is a period when the selection transistor is turned on by outputting the open signal to the first scan line, and the driving stop signal is supplied to the driving transistor from the voltage source through the current path to turn off the driving transistor so that the electro-optical element stops emitting light,

the lights-off period is a period when the selection transistor is turned off by outputting the close signal to the first scan line, and the electro-optical element retains a non-light-emitting state, and

the first scan line is formed by one or a plurality of wiring layers having a time constant in which the signal delay of the open/close signals is 10% or less of a theoretical value, and

the current control terminal of the selection transistor is connected to one or a plurality of wiring layers.

8. The electro-optical device according to claim 7, further comprising:

a reproduction selection transistor that opens/closes a current path supplying the driving current from the driving transistor to the electro-optical element; and

a second scan line that outputs an open/close signal that turns on/off the reproduction selection transistor,

wherein the second scan line is formed by one or a plurality of wiring layers having a time constant in which the signal delay of the open/close signals is 10% or less of a theoretical value, and

a current control terminal of the reproduction selection transistor is connected to one or a plurality of wiring layers.

9. The electro-optical device according to claim 7,

wherein the data line is formed by one or a plurality of wiring layers having a time constant in which the signal delay of the open/close signals is 10% or less of a theoretical value, and

the current output terminal of the driving transistor is connected to one or a plurality of wiring layers.

10. The electro-optical device according to claim 7,

wherein the time constant of the wiring layer is set by increasing/decreasing a resistance component using a thickness and/or a line width of the first scan line, the second scan line, or the data line as a parameter.

11. The electro-optical device according to claim 7,

wherein the time constant of the wiring layer is set by increasing/decreasing a resistance component using the specific resistance of a material used for forming the first scan line, the second scan line, or the data line as a parameter.

17. A method of manufacturing an electro-optical device comprising:

a driving transistor that includes a current control terminal, a current input terminal, and a current output terminal, and controls a current amplifying ratio on the basis of a voltage between the current control terminal and the current input terminal;

an electro-optical element that is supplied with the driving current from the driving transistor to emit light;

a storage capacitor that stores the charge corresponding to the voltage between the current control terminal and the current input terminal of the driving transistor;

a constant current source that outputs a constant independent of the light emission gray-scale level;

a voltage source that outputs a driving stop signal that turns off the driving transistor;

a selection transistor that opens/closes a current path connecting any one of the constant current source and the voltage source with the driving transistor; and

a scan line that outputs open/close signals that turn on/off the selection transistor,

in which one frame has a program period, a light-emitting period, an erasing period, and a lights-off period, and the light-emitting period is controlled according to a light emission gray-scale level,

the program period is a period when the selection transistor is turned on by outputting an open signal to the scan line, and when the constant current flows from the constant current source to the driving transistor through the current path, the charge corresponding to the voltage between the current control terminal and the current input terminal is stored in the storage capacitor,

the light-emitting period is a period when the selection transistor is turned off by outputting a close signal to the scan line, and the voltage corresponding to the charge stored in the storage capacitor is supplied between the current control terminal and the current input terminal of the driving transistor to supply the driving current to the electro-optical element,

the erasing period is a period when the selection transistor is turned on by outputting the open signal to the scan line, and the driving stop signal is supplied to the driving transistor from the voltage source through the current path to turn off the driving transistor so that the electro-optical element stops emitting light,

the lights-off period is a period when the selection transistor is turned off by outputting the close signal to the scan line, and the electro-optical element retains a non-light-emitting state, and

the time constant of the scan line is set so that the signal delay of the open/close signals is 10% or less of a theoretical value, the method comprising;

forming the driving transistor on a temporary substrate;

forming a signal line which connects the driving transistor with the electro-optical element on a wiring substrate; and

bonding the driving transistor to the wiring substrate to connect the driving transistor with the signal line.

18. The method of manufacturing an electro-optical device according to claim 17,

wherein the time constant of the scan line is set by increasing/decreasing a resistance component using a thickness and/or a line width of the scan line as a parameter.

19. The method of manufacturing an electro-optical device according to claim 17,

wherein the time constant of the scan line is set by increasing/decreasing a resistance component using the specific resistance of a material used for forming the scan line as a parameter.

20. The method of manufacturing an electro-optical device according to claim 17,

wherein the time constant of the scan line is set by increasing/decreasing a capacitance component using a distance between adjacent scan lines as a parameter.

21. The method of manufacturing an electro-optical device according to claim 17,

wherein the time constant of the scan line is set by increasing/decreasing a capacitance component using a relative dielectric constant of a material used for forming an insulating film arranged above and/or below the scan line as a parameter.

22. The method of manufacturing an electro-optical device according to claim 17,

wherein the time constant of the scan line is set by increasing/decreasing a capacitance component using a thickness of a material used for forming an insulating film arranged above and/or below the scan line as a parameter.

23. The method of manufacturing an electro-optical device according to claim 17,

wherein the electro-optical element is an organic electroluminescent element.

24. An electronic apparatus comprising the electro-optical device manufactured by the method according to claim 17.