CN104658469B - Organic light emitting display device and driving method thereof - Google Patents

Abstract

An organic light emitting display device and a driving method. The organic light emitting display device includes a plurality of pixel circuits and a plurality of dummy pixel circuits. The pixel circuits are electrically connected to a plurality of current sources, and the pixel circuits form a plurality of pixel rows. The dummy pixel circuits are electrically connected to the current sources and form a dummy pixel row. The current sources precharge the dummy pixel circuits of the dummy pixel row before the current sources charge the pixel circuits of one of the pixel rows.

Description

Organic light emitting display device and driving method thereof

technical field

The present invention relates to an organic light emitting display device and a driving method thereof, and in particular to an organic light emitting display device and a driving method thereof capable of improving image display quality.

Background technique

Driving methods of an organic light emitting display (OLED) device include a voltage driving method and a current driving method. Among them, the advantage of the current driving method is that the gray scale of the pixel will not shift due to the variation of the threshold voltage and mobility of the driving transistor, thereby causing the problem of unevenness in the display screen. However, when the size of the organic light-emitting display device increases, the driving circuit of the organic light-emitting display device increases and its load is too large, so that the pixel circuit cannot be charged to the power required to display the corresponding gray value within a limited charging time. Therefore, the image display quality of the organic light emitting display device is degraded.

Contents of the invention

Therefore, the purpose of the present invention is to provide an organic light emitting display (organic light emitting display; OLED) device and its driving method, which can charge the pixel circuit to the power required to display the corresponding gray value before the pixel circuit enters the light emitting stage , thereby improving the display quality of the picture.

According to the above object of the present invention, an organic light emitting display device is proposed, which includes a plurality of first pixel circuits and a plurality of second dummy pixel circuits. Each of the first pixel circuits is electrically connected to one of the multiple current sources, and the first pixel circuits form multiple first pixel rows. Each of the second dummy pixel circuits is electrically connected to one of the current sources, and the second dummy pixel circuits form a second dummy pixel row. Before the current sources charge the first pixel circuit in one of the first pixel rows, the current sources precharge the second dummy pixel circuit in the second dummy pixel row.

According to an embodiment of the present invention, the pre-charging time corresponding to the second dummy pixel row is longer than the charging time corresponding to the first pixel row.

According to yet another embodiment of the present invention, the first pixel circuit is located within a display area of the organic light emitting display device, and the second dummy pixel circuit is located outside the display area.

According to yet another embodiment of the present invention, the above-mentioned current sources are a plurality of current mirror circuits.

According to yet another embodiment of the present invention, each first pixel circuit of the first pixel circuit and each second dummy pixel circuit of the second dummy pixel circuit include a driving circuit, and each first pixel circuit of the first pixel circuit The pixel circuit also includes a light emitting element.

According to the above object of the present invention, another driving method is proposed, which is applicable to an organic light-emitting display device having a plurality of first pixel circuits and a plurality of second dummy pixel circuits, and these first pixel circuits form a plurality of first pixel rows, These second dummy pixel circuits form a second dummy pixel row, these first pixel circuits and these second dummy pixel circuits are electrically connected to a plurality of current sources, and the driving method includes using these current sources to the second dummy pixel row The second dummy pixel circuits are precharged, and the first pixel circuits in one row of the first pixel rows are charged by the current sources.

According to an embodiment of the present invention, the pre-charging time corresponding to the second dummy pixel row is longer than the charging time corresponding to the first pixel row.

According to yet another embodiment of the present invention, the first pixel circuit is located within a display area of the organic light emitting display device, and the second dummy pixel circuit is located outside the display area.

According to yet another embodiment of the present invention, the above-mentioned current source is a plurality of current mirror circuits.

According to yet another embodiment of the present invention, each first pixel circuit of the first pixel circuit and each second dummy pixel circuit of the second dummy pixel circuit include a driving circuit, and each first pixel circuit of the first pixel circuit The pixel circuit also includes a light emitting element.

Description of drawings

In order to make the above and other objects, features, advantages and embodiments of the present invention more comprehensible, the description is as follows with reference to the accompanying drawings:

FIG. 1 shows a schematic diagram of an organic light emitting display device according to an embodiment of the present invention;

FIG. 2 shows a schematic diagram of the pixel circuit in FIG. 1;

FIG. 3 shows a schematic diagram of the virtual pixel circuit in FIG. 1; and

FIG. 4 is a timing diagram of the gate lines in FIG. 1 .

【Symbol Description】

100: Organic light-emitting display device

110: Source driver

111(1)～111(M): current source

120: Gate driver

130: Pixel circuit area

CT: charging time

DC: drive circuit

DP: virtual pixel circuit

DR: Dummy pixel row

GL(1)～GL(N+1): gate line

GND: ground terminal

OLED: light emitting element

P: pixel circuit

PCT: precharge time

R(1)～R(N): pixel row

SL(1)～SL(M): Source line

VA: display area

VDD, VS: input voltage terminal

detailed description

Embodiments of the invention are discussed in detail below. It should be appreciated, however, that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are illustrative only, and do not limit the scope of the invention.

Referring to FIG. 1 , it shows a schematic diagram of an organic light emitting display device 100 according to an embodiment of the present invention. The organic light emitting display device 100 is a display driven by current. The organic light emitting display device 100 includes a source driver 110 , a gate driver 120 and a pixel circuit region 130 . The source driver 110 includes current sources 111(1)-111(M), which are respectively electrically connected to the pixel circuit area 130 through source lines SL(1)-SL(M), so as to supply the current required to drive the pixel circuit area 130. . The current sources 111(1)˜111(M) may be current mirror circuits, but are not limited thereto. The gate driver 120 is electrically connected to the pixel circuit area 130 through the gate lines GL( 1 )˜GL(N+1) to control and drive the state of the pixel circuit area 130 .

The pixel circuit area 130 has M×(N+1) pixel units, which are divided into pixel circuits P and dummy pixel circuits DP. All pixel circuits P are located in the display area VA, and the arrangement of all pixel circuits P forms N pixel rows R( 1 )˜R(N) with the same number of pixel circuits P. The states of the pixel circuits P in the pixel rows R( 1 )-R(N) are respectively controlled by the gate lines GL( 1 )-GL(N). All dummy pixel circuits DP are located on a side away from the current sources 111(1)-111(M) outside the display area VA, and the arrangement of all dummy pixel circuits DP forms a dummy pixel row DR. The state of the dummy pixel circuit DP in the dummy pixel row DR is controlled by the gate line GL(N+1). In other embodiments, the dummy pixel circuit DP may be selectively disposed on a side near the current sources 111(1)˜111(M) outside the display area VA.

Referring to FIG. 2 , it shows a schematic diagram of the pixel circuit P in FIG. 1 . The pixel circuit P includes a driving circuit DC and a light emitting element OLED. The driving circuit DC is electrically connected to the source line SL(i), the gate line GL(j), the ground terminal GND and one end of the light emitting element OLED, and the other end of the light emitting element OLED is electrically connected to the input voltage terminal VDD. The source line SL(i) is one of the source lines SL(1)-SL(M) in FIG. 1, and the gate line GL(j) is the gate line GL(1)-GL( one of N). The driving circuit DC and the light-emitting element OLED are jointly driven by the source line SL(i), the gate line GL(j), the input voltage terminal VDD and the ground terminal GND, so that the light-emitting element OLED can be input according to the source line SL(i) The signal shows the corresponding gray value.

Referring to FIG. 3 , it shows a schematic diagram of the dummy pixel circuit DP in FIG. 1 . The dummy pixel circuit DP includes a driving circuit DC electrically connected to a source line SL(i), a gate line GL(N+1), a ground terminal GND and an input voltage terminal VS. The driving circuit DC is jointly driven by the source line SL(i), the gate line GL(N+1), the input voltage terminal VS and the ground terminal GND.

Comparing FIG. 2 and FIG. 3 , it can be seen that the dummy pixel circuit DP lacks the light-emitting element OLED. This is because the dummy pixel circuit DP is located outside the display area VA, and the dummy pixel circuit DP may not be provided with a light-emitting element OLED. In addition, the levels of the input voltage terminal VS and the input voltage terminal VDD can be the same or different.

It should be noted that the drive circuit DC in the embodiment of the present invention is a circuit (4T1C) composed of 4 transistor elements and 1 capacitive element as an example, and those skilled in the art can make the drive circuit DC shown in FIG. 2 Substitution or alteration, such as replacement with a 5T1C circuit or a 6T2C circuit. Therefore, any replacement or modification of the pixel circuit DC should be covered by the present invention.

Referring to FIG. 4 , it shows a timing diagram of the gate lines GL( 1 )˜GL(N+1) in FIG. 1 . First, switch the gate line GL(N+1) to a high level to precharge the dummy pixel circuit DP of the dummy pixel row DR. After the pre-charging step for the dummy pixel circuit DP is completed, switch the gate line GL(N+1) to a low level, and then switch the gate line GL(1) to a high level, so as to charge the pixel row R(1) The pixel circuit P is charged. After the pixel circuit P of the pixel row R( 1 ) is charged, the gate line GL( 1 ) is switched to a low level, so that the pixel circuit P of the pixel row R( 1 ) enters a light emitting stage. At this time, the gate line GL(N+1) is switched to a high level again to precharge the dummy pixel circuit DP of the dummy pixel row DR. After the pre-charging step for the dummy pixel circuit DP is completed, switch the gate line GL(N+1) to a low level, and then switch the gate line GL(2) to a high level, so as to charge the pixel row R(2) The pixel circuit P is charged. According to the above rules, the pixel circuits P of the pixel rows R( 1 )-R(N) are sequentially entered into the light-emitting phase, and the display of the picture is completed.

In short, before the pixel circuit P of any pixel row R(i) enters the light-emitting phase, the gate line GL(N+1) is switched to a high level, so as to activate the dummy pixel circuit DP of the dummy pixel row DR. precharge. After the pre-charging step for the dummy pixel circuit DP is completed, switch the gate line GL(N+1) to a low level, and then switch the gate line GL(i) to a high level to charge the pixel row R(i) The pixel circuit P is charged. After the pixel circuit P of the pixel row R(i) is charged, the gate line GL(i) is switched to a low level, so that the pixel circuit P of the pixel row R(i) enters the light-emitting stage, and then the dummy pixel row DR The dummy pixel circuit DP is precharged to prepare to drive the pixel circuit P of the next pixel row R(i+1).

In the embodiment of the present invention, before charging the pixel circuits P of the pixel rows R(1)-R(N), the dummy pixel circuits DP of the dummy pixel row DR are precharged first, so that the source line SL ( 1) The potentials of SL(M) can be pre-charged to a level. After the pre-charging step is completed, when charging the pixel circuit P of the pixel rows R(1)-R(N), the time for the potentials of the source lines SL(1)-SL(M) to be charged to the required level is as short as It can be shortened so that the source lines SL( 1 )˜SL(M) can be charged to the required level within the charging time, so that the pixel circuit P can correctly display the corresponding gray value during the light emitting stage. Therefore, the embodiment of the present invention can improve the display quality of the picture. Preferably, the pre-charging time PCT for the dummy pixel circuit DP is longer than the charging time CT for the pixel circuit P, so as to maintain the length of the light-emitting phase of the pixel circuit P and avoid display problems such as screen flickering.

To sum up, the organic light-emitting display device and driving method of the present invention can charge the pixel circuit to the power required to display the corresponding gray value before the pixel circuit enters the light-emitting stage, so that the pixel circuit can display correctly during the light-emitting stage. The corresponding gray value, thereby improving the display quality of the picture.

Although the present invention has been disclosed above in terms of implementation, it is not intended to limit the present invention. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be determined by what is defined in the claims.

Claims (10)

1. An organic light-emitting display device, comprising: a plurality of first pixel circuits, each of the first pixel circuits is electrically connected to one of the plurality of current sources, and the first pixel circuits form a plurality of first pixel rows; and a plurality of second dummy pixel circuits, each of the second dummy pixel circuits is electrically connected to one of the current sources, and the second dummy pixel circuits form a second dummy pixel row; Wherein, before the current sources charge the first pixel circuits in one of the first pixel rows, the current sources precharge the second dummy pixel circuits in the second dummy pixel row; Wherein, before the first pixel circuit of any first pixel row enters the light-emitting phase, the second dummy pixel circuit of the second dummy pixel row is precharged; after the precharging of the second dummy pixel circuit is completed, Afterwards, charging the first pixel circuit in the first pixel row; after the charging of the first pixel circuit is completed, making the first pixel circuit in the first pixel row enter a light-emitting phase. 2. The organic light emitting display device according to claim 1, wherein the precharging time corresponding to the second dummy pixel row is longer than the charging time corresponding to the first pixel row. 3. The organic light emitting display device according to claim 1, wherein the first pixel circuits are located within a display area of the organic light emitting display device, and the second dummy pixel circuits are located outside the display area away from the current sources side. 4. The organic light emitting display device according to claim 1, wherein the current sources are a plurality of current mirror circuits. 5. The organic light emitting display device according to claim 1, wherein each of the first pixel circuits and each of the second dummy pixel circuits includes a driving circuit, and each of the first pixel circuits further Includes light emitting element. 6. A driving method, suitable for an organic light emitting display device, the organic light emitting display device has a plurality of first pixel circuits and a plurality of second dummy pixel circuits, these first pixel circuits form a plurality of first pixel rows, these The second dummy pixel circuits form a second dummy pixel row, the first pixel circuits and the second dummy pixel circuits are electrically connected to a plurality of current sources, and the driving method includes: precharging the second dummy pixel circuits of the second dummy pixel row by the current sources; and charging the first pixel circuits in one of the first pixel rows by the current sources; Wherein, before the first pixel circuit of any first pixel row enters the light-emitting phase, the second dummy pixel circuit of the second dummy pixel row is precharged; after the precharging of the second dummy pixel circuit is completed, Afterwards, charging the first pixel circuit in the first pixel row; after the charging of the first pixel circuit is completed, making the first pixel circuit in the first pixel row enter a light-emitting phase. 7. The driving method according to claim 6, wherein the precharging time corresponding to the second dummy pixel row is longer than the charging time corresponding to the first pixel row. 8. The driving method according to claim 6, wherein the first pixel circuits are located in the display area of the organic light emitting display device, and the second dummy pixel circuits are located on the side away from the current sources outside the display area . 9. The driving method according to claim 6, wherein the current sources are a plurality of current mirror circuits. 10. The driving method according to claim 6, wherein each of the first pixel circuits and each of the second dummy pixel circuits comprises a driving circuit, and each of the first pixel circuits further comprises a light emitting element.