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

• US 7,315,295 B2
• Filed: 09/21/2001
• Issued: 01/01/2008
• Est. Priority Date: 09/29/2000
• Status: Expired due to Term

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kimura, Mutsumi
• Primary Examiner(s): LEWIS, DAVID LEE
• Application Number:
  US09/956,994
• Publication Number:
  US 20020044109A1
• Time in Patent Office: 2,293 Days
• Field of Search: 345 60-100, 345/204, 345/214, 345/211, 315/169.1, 315/169.2, 315/169.3
• US Class Current: 345/92
• CPC Class Codes: G09G 2300/0417 Special arrangements specific to the use of low carrier mobility technology
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• 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

The invention provides a method for implementing a multi-level display of an electro-optical device according to a time ratio gray-scale method without providing reset lines. In an electro-optical device that 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, and a switching transistor that controls the driving transistor, a gray-scale is obtained by performing a plurality of set-reset operations. Each set-reset operation includes: a setting step of supplying an on-signal 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 the one signal; and a resetting step of supplying an on-signal to the switching transistor via the scanning line, and of supplying a reset signal to select the non-conducting state of the driving transistor to the driving transistor via the data line and the switching transistor in accordance with the one signal.

Claims

1. A driving method for an electro-luminescent device which includes, corresponding to an intersection of a scanning line and a data line, a power line, an electro-luminescent element, a driving transistor that controls a current flowing through the electro-luminescent element, the electro-luminescent element emitting light by the current and a switching transistor that controls the driving transistor, the driving method comprising:

a setting step of supplying a first on-signal 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 first on-signal is supplied;

a resetting step of supplying a second on-signal to the switching transistor via the scanning line, and of supplying a reset signal to select the 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 second on-signal is supplied; and

a horizontal scanning period that includes a first sub horizontal scanning period to perform the setting step and a second sub horizontal scanning period to perform the resetting step;

wherein

the period for which the first on-signal is supplied coincides with a period for which the set signal is supplied.

2. The driving method for an electro-luminescent device according to claim 1, further including performing the setting step in a first horizontal scanning period, and performing the resetting step in a second horizontal scanning period.

3. The driving method for an electro-luminescent 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.

4. The driving method for an electro-luminescent device according to claim 3, further including providing a time interval between the setting step and the resetting step that is different for each of the plurality of set-reset operations.

5. The driving method for an electro-luminescent device according to claim 3, 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 each other, and the ratio of time intervals for the plurality of set-reset operations being set to be about 1:

2;

. . . ;

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

6. The driving method for an electro-luminescent device according to claim 1, further including providing the set signal to be a signal for setting the conducting state for the driving transistor rather than the signal for selecting the conducting state or the non-conducting state of the driving transistor.

7. The driving method for an electro-luminescent device according to claim 1, further including driving the electro-luminescent element including an organic electro-luminescence element.

8. An electro-luminescent device driven by the driving method according to claim 1.

13. An electronic apparatus, comprising:

the electro-luminescent device set forth in claim 8.

9. An electro-luminescent device, comprising:

a scanning line;

a data line;

a power line;

an electro-luminescent element corresponding to an intersection of the scanning line and the data line;

a driving transistor that controls a current flowing through the electro-luminescent element, the electro-luminescent element emitting light by the current;

a switching transistor that controls the driving transistor;

a drive circuit that generates a signal to set the switching transistor to be an on-state or an off-state, and that generates a signal to set or reset the driving transistor in accordance with the signal to set the switching transistor to be the on-state or the off-state; and

a horizontal scanning period that includes a first sub horizontal scanning period to perform the setting step and a second sub horizontal scanning period to perform the resetting step;

wherein

a period for which a first on-signal is supplied to the switching transistor coincides with a period for which the set signal is supplied.

12. The electro-luminescent device according to claim 9, the electro-luminescent element including an organic electro-luminescence element.

10. An electro-luminescent device, comprising:

a scanning line;

a data line;

a power line;

an electro-luminescent element corresponding to an intersection at the scanning line and the data line;

a driving transistor that controls a current flowing through the electro-luminescent element, the electro-luminescent element emitting light by the current;

a switching transistor that controls the driving transistor;

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

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

a period of supplying the signal to reset the driving transistor via the data line within a vertical scanning period being substantially constant; and

a horizontal scanning period that includes a first sub horizontal scanning period to perform the setting step and a second sub horizontal scanning period to perform the resetting step;

wherein

a period for which a first on-signal is supplied to the switching transistor coincides with a period for which the set signal is supplied.

11. An electro-luminescent device, comprising:

a scanning line;

a data line;

a power line;

an electro-luminescent element corresponding to an intersection of the scanning line and the data line;

a driving transistor that controls a current flowing through the electro-luminescent element, the electro-luminescent element emitting light by the current;

a switching transistor that controls the driving transistor, an on-signal to perform a setting step of setting the electro-luminescent element and a resetting step of resetting the electro-luminescent element being supplied to the switching transistor via the scanning line;

a horizontal scanning period that includes a first sub horizontal scanning period to perform the setting step and a second sub horizontal scanning period to perform the resetting step; and

the number of the signal to perform the setting step and the signal to perform the resetting step being substantially the same;

wherein

a period for which a first on-signal is supplied to the switching transistor coincides with a period for which the set signal is supplied.

14. A driving method for an electro-luminescent device which includes, corresponding to an intersection of a scanning line and a data line, an electro-luminescent element, a driving transistor that controls a current flowing through the electro-luminescent element, the electro-luminescent element emitting light by the current and a switching transistor that controls the driving transistor, the driving method comprising:

a setting step of supplying a first on-signal 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 first on-signal is supplied;

a resetting step of supplying a second on-signal to the switching transistor via the scanning line, and of supplying a reset signal to select the 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 second on-signal is supplied, the setting step and the resetting step forming a set-reset operation;

a plurality of the set-reset operation being performed within one frame period, at least two set-reset operations of the plurality of the set-reset operation having mutually different time lengths; and

a horizontal scanning period that includes a first sub horizontal scanning period to perform the setting step and a second sub horizontal scanning period to perform the resetting step;

wherein

the period for which the first on-signal is supplied coincides with a period for which the set signal is supplied.

15. An electro-luminescent device, comprising:

a scanning line;

a data line;

a power line;

an electro-luminescent element corresponding to an intersection of the scanning line and the data line;

a driving transistor that controls a current flowing through the electro-luminescent element, the electro-luminescent element emitting light by the current,

a switching transistor that controls the driving transistor, an on-signal to perform a setting step of setting the electro-luminescent element and a resetting step of resetting the electro-luminescent element being supplied to the switching transistor via the scanning line;

a horizontal scanning period that includes a first sub horizontal scanning period to perform the setting step and a second sub horizontal scanning period to perform the resetting step; and

a plurality of the pairs of the setting step and the resetting step being performed within one frame period;

wherein

a period for which a first on-signal is supplied to the switching transistor coincides with a period for which the set signal is supplied.