Driving method for electro-optical device, electro-optical device, and electronic apparatus

• US 6,781,567 B2
• Filed: 09/21/2001
• Issued: 08/24/2004
• Est. Priority Date: 09/29/2000
• Status: Expired due to Term

• Current Assignee: Element Capital Commercial Company Pte. Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kimura, Mutsumi
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): LEWIS, DAVID LEE
• Application Number:
  US09/956,995
• Publication Number:
  US 20020041276A1
• Time in Patent Office: 1,068 Days
• Field of Search: 345/76, 345/87-100, 345/204, 345/211, 345/214, 315/169.1, 315/169.2, 315/169.3
• US Class Current: 345/92
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks

Abstract

To provide a method for implementing a gray-scale display of an electro-optical device according to a time ratio gray-scale method without providing reset lines.

In an electro-optical device comprising, at an intersection of a scanning line and a data line, an electro-optical element, a driving transistor for driving the electro-optical element, a switching transistor for controlling the driving transistor, and a reset transistor having the function of resetting the driving transistor to a non-conducting state, a gray-scale is obtained by performing a plurality of set-reset operations, each set-reset operation comprising: a setting step of supplying an on-signal to the switching transistor via the scanning line, and of supplying a set signal for selecting a conducting state or a non-conducting state of the driving transistor to the driving transistor via the data line and the switching transistor in accordance with the on-signal; and a resetting stop of supplying an on-signal for the reset transistor via the scanning line so as to reset the driving transistor to the non-conducting state.

Claims

1. A driving method for an electro-optical device which includes, at an intersection of a scanning line and a data line, an electro-optical element, a driving transistor that drives the electro-optical element, a switching transistor that controls the driving transistor, and a reset transistor that resets the driving transistor to a non-conducting state, the driving method comprising:

a setting step of supplying an on-signal to cause the switching transistor to be in an on-state to the switching transistor via the scanning line, and of supplying a set signal to select a conducting state or a non-conducting state of the driving transistor to the driving transistor via the data line and the switching transistor in accordance with a period for which the on-signal is supplied; and

a resetting step of supplying an on-signal to cause the reset transistor to be an on-state to the reset transistor via the scanning line so as to reset the driving transistor to the non-conducting state.

2. A driving method for an electro-optical device according to claim 1, further including, with a power line, supplying a current to the electro-optical element via the driving transistor, and connecting one end of the reset transistor to the power line.

3. The driving method for an electro-optical device according to claim 1, further including providing a conductivity type of the switching transistor and a conductivity type of the reset transistor that are different from each other.

4. The driving method for an electro-optical device according to claim 1, further including providing conductivity types of the switching transistor, the driving transistor, and the reset transistor that are respectively n-type, p-type, and p-type.

5. The driving method for an electro-optical device according to claim 4, further including providing a voltage VS corresponding to the on-signal to cause the switching transistor to be in the on-state, a voltage VR corresponding to the on-signal to cause the reset transistor to be in the on-state, and a voltage V0 corresponding to an off-signal to cause the switching transistor and the reset transistor to be in an off-state so as to satisfy a relational expression:

VS>

V0>

VR.

6. The driving method for an electro-optical device according to claim 5, further including providing the voltage VS, the voltage VR, and the voltage V0 so as to satisfy relational expressions:

−

VS≈

, VR and V0=0V (voltages).

7. The driving method for an electro-optical device according to claim 1, further including, while the switching transistor is in the on-state, providing the reset transistor in the off-state, and, while the reset transistor is in the on-state, providing the switching transistor in the off-state.

8. The driving method for an electro-optical device according to claim 1, further including obtaining a gray-scale by setting a time interval between the setting step and the resetting step.

9. The driving method for an electro-optical device according to claim 1, further including obtaining a gray-scale by performing a plurality of set-reset operations, each set-reset operation including the setting step and the resetting step.

10. The driving method for an electro-optical device according to claim 9, further including the time interval between the setting step and the resetting step to be different for each of the plurality of set-reset operations.

11. The driving method for an electro-optical device according to claim 9, further including providing the time interval between the setting step and the resetting step for each of the plurality of set-reset operations to be completely different from the others, and the ratio of time intervals for the plurality of set-reset operations to be about 1:

2;

. . . ;

2ⁿ (n being an integer of one or more) based on the minimum time interval.

12. The driving method for an electro-optical device according to claim 1, further including providing the set signal to be a signal to set the driving transistor to the conducting state rather than the signal to select the conducting state or the on-conducting state of the driving transistor.

13. The driving method for an electro-optical device according to claim 1, further including providing the electro-optical element that includes an organic electro-luminescence element.

14. An electro-optical device driven by the driving method according to claim 1.

20. An electronic apparatus, comprising:

the electro-optical device set forth in claim 14.

15. An electro-optical device, comprising:

a scanning line;

a data line;

an electro-optical element at an intersection of the scanning line and the data line;

a driving transistor that drives the electro-optical element;

a switching transistor that controls the driving transistor;

a reset transistor that resets the driving transistor to a non-conducting state;

at least one drive circuit that generates a signal to set the switching transistor and the reset transistor to be in an on-state or an off-state via the scanning line, and that generates a signal to set the driving transistor in accordance with the signal to set the switching transistor to be in the on-state.

18. The electro-optical device according to claim 15, the electro-optical device further including a power line that supplies a current to the electro-optical element via the driving transistor, and one end of the reset transistor being connected to the power line.

19. The electro-optical device according to claim 15, the electro-optical element including an organic electro-luminescence element.

16. An electro-optical device, comprising:

a scanning line;

a data line;

an electro-optical element at an intersection of the scanning line and the data line;

a driving transistor that drives the electro-optical element;

a switching transistor that controls the driving transistor;

a reset transistor that resets the driving transistor to a non-conducting state;

a scanning line driver that supplies a signal to set the switching transistor and the reset transistor to be in an on-state or an off-state to the scanning line; and

a data line driver that supplies a signal to set the driving transistor to the data line in accordance with an operation of the scanning line driver.

17. An electro-optical device comprising:

a scanning line;

a data line;

an electro-optical element at an intersection of the scanning line and the data line;

a driving transistor that drives the electro-optical element;

a switching transistor that controls the driving transistor; and

a reset transistor that resets the driving transistor to a non-conducting state, an on-signal that performs a setting step of setting the electro-optical element being supplied to the switching transistor via the scanning line, and an on-signal that performs a resetting step of resetting the electro-optical element being supplied to the reset transistor via the scanning line.