TWI511111B - Organic light emitting display device and driving method thereof - Google Patents

Description

Organic light emitting display device and driving method thereof

The present invention relates to an organic light emitting display device and a driving method thereof, and more particularly to an organic light emitting display device capable of improving picture display quality and a driving method thereof.

The driving method of the organic light emitting display (OLED) device includes a voltage driving method and a current driving method. Among them, the current driving method has an advantage in that the pixel gray scale does not shift due to variations in the threshold voltage and the mobility rate of the driving transistor, thereby causing a problem that the display screen is uneven. However, when the size of the organic light-emitting display device is increased, the driving line of the organic light-emitting display device is increased to cause an excessive load thereof, resulting in failure to charge the pixel circuit to a power amount for displaying a corresponding gray scale value within a limited charging time. The screen display quality of the organic light-emitting display device is thus degraded.

Therefore, an object of the present invention is to provide an organic light emitting display (OLED) device and a driving method thereof, which can charge a pixel circuit to display a corresponding grayscale value before the pixel circuit enters the light emitting phase. The amount of power, which in turn improves the display quality of the picture.

According to the above object of the present invention, an organic light emitting display device comprising a plurality of pixel circuits and a plurality of dummy pixel circuits is proposed. Each of the pixel circuits of the pixel circuits is electrically connected to one of the plurality of current sources, and the pixel circuits form a plurality of pixel columns. Each of the virtual pixel circuits of the virtual pixel circuits is electrically connected to one of the current sources, and the virtual pixel circuits form a virtual pixel column. Before the current sources charge the pixel circuits in one of the pixel columns of the pixel columns, the current sources precharge the virtual pixel circuits of the virtual pixel columns.

According to an embodiment of the invention, the pre-charging time corresponding to the virtual pixel column is greater than the charging time corresponding to the pixel column.

According to still another embodiment of the present invention, the pixel circuit is located in a display area of the organic light emitting display device, and the virtual pixel circuit is located outside the display area.

According to still another embodiment of the present invention, the current source is a plurality of current mirror circuits.

According to still another embodiment of the present invention, each of the pixel circuits of the pixel circuit and each of the virtual pixel circuits includes a driving circuit, and each pixel circuit of the pixel circuit further includes a light emitting element.

According to the above object of the present invention, a driving method is further provided, which is applicable to an organic light emitting display device having a plurality of pixel circuits and a plurality of virtual pixel circuits, wherein the pixel circuits form a plurality of pixel columns, and the pixels are formed. The circuit forms a virtual pixel column, and the pixel circuits and the virtual pixel circuits are electrically connected to the plurality of current sources, and the driving method comprises: The virtual pixel circuit of the pseudo-column is precharged, and the pixel circuits of one of the pixel columns are charged by the current sources.

According to an embodiment of the invention, the pre-charging time corresponding to the virtual pixel column is greater than the charging time corresponding to the pixel column.

According to still another embodiment of the present invention, the pixel circuit is located in a display area of the organic light emitting display device, and the virtual pixel circuit is located outside the display area.

According to still another embodiment of the present invention, the current source is a plurality of current mirror circuits.

According to still another embodiment of the present invention, each of the pixel circuits of the pixel circuit and each of the virtual pixel circuits includes a driving circuit, and each pixel circuit of the pixel circuit further includes a light emitting element.

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‧‧‧Virtual Picture Column

GL(1)~GL(N+1)‧‧‧ gate line

GND‧‧‧ ground

OLED ‧ ‧ luminescent components

P‧‧‧ pixel circuit

PCT‧‧‧Precharge time

R(1)~R(N)‧‧‧

SL(1)~SL(M)‧‧‧ source line

VA‧‧‧ display area

VDD, VS‧‧‧ input voltage terminal

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood. The description of the drawings is as follows: Figure 1 shows an organic light emitting display (OLED) according to an embodiment of the present invention. 2 is a schematic diagram of a pixel circuit in FIG. 1; FIG. 3 is a schematic diagram showing a virtual pixel circuit in FIG. 1; and FIG. 4 is a diagram showing a gate in FIG. Timing diagram of the polar line.

Embodiments of the invention are discussed in detail below. However, it will be appreciated that the embodiments provide many applicable inventive concepts that can be implemented in a wide variety of specific content. The specific embodiments discussed are for illustrative purposes only and are not It is intended to define the scope of the invention.

Please refer to FIG. 1 , which is a schematic diagram of an organic light emitting display (OLED) device 100 according to an embodiment of the present invention. The organic light emitting display device 100 is a display that is driven using 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) to 111(M) electrically connected to the pixel circuit region 130 through the source lines SL(1) to SL(M) to supply the driving pixel circuit region 130. The current required. The current sources 111(1) to 111(M) may be current mirror circuits, but are not limited thereto. The gate driver 120 is electrically connected to the pixel circuit region 130 through the gate lines GL(1) to GL(N+1) to control the state of the driving pixel circuit region 130.

The pixel circuit area 130 has M × (N + 1) pixel units, and these pixel units are divided into a pixel circuit P and a dummy pixel circuit DP. All of the pixel circuits P are located in the display area VA, and the arrangement of all the pixel circuits P forms N pixel columns R(1) to R(N) having the same number of pixel circuits P. The P state of the pixel circuit in the pixel sequence R(1) to R(N) is controlled by the gate lines GL(1) to GL(N), respectively. All of the virtual pixel circuits DP are located on the side away from the current sources 111(1) to 111(M) outside the display area VA, and the arrangement of all the virtual pixel circuits DP forms the virtual pixel sequence DR. The virtual pixel circuit DP state in the virtual pixel sequence DR is controlled by the gate line GL(N+1). In other embodiments, the virtual pixel circuit DP may be disposed on a side of the display area VA that is adjacent to the current sources 111(1) to 111(M).

Please refer to FIG. 2, which shows the pixel circuit P in FIG. intention. 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) to SL(M) in FIG. 1, and the gate line GL(j) is the gate line GL(1) in FIG. One of GL(N). The driving circuit DC and the light emitting element OLED are 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 grayscale value.

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

Comparing FIGS. 2 and 3, the virtual pixel circuit DP lacks the light-emitting element OLED. This is because the virtual pixel circuit DP is located outside the display area VA, and the virtual pixel circuit DP may not be provided with the light-emitting element OLED. In addition, the level of the input voltage terminal VS and the input voltage terminal VDD may be the same or different.

It should be noted that the driving circuit DC of the embodiment of the present invention is exemplified by a circuit (4T1C) composed of four transistor elements and one capacitor element, and the driving circuit disclosed in FIG. 2 can be easily used by those skilled in the art. The DC is replaced or changed, for example, replaced by a 5T1C circuit or a 6T2C circuit. Therefore, any substitutions or changes made to the pixel circuit DC should be covered by the present invention. cover.

Please refer to FIG. 4, which is a timing chart of the gate lines GL(1) to GL(N+1) in FIG. First, the gate line GL(N+1) is switched to a high level to precharge the virtual pixel circuit DP of the virtual pixel sequence DR. After the pre-charging step of the virtual pixel circuit DP is completed, the switching gate line GL(N+1) is at a low level, and then the gate line GL(1) is switched to a high level to correspond to the pixel column R(1). The pixel circuit P is charged. After the pixel circuit P of the pixel sequence R(1) is charged, the gate line GL(1) is switched to a low level, and the pixel circuit P of the pixel column R(1) enters the light-emitting phase. At this time, the gate line GL(N+1) is again switched to the high level to precharge the virtual pixel circuit DP of the virtual pixel sequence DR. After the pre-charging step of the virtual pixel circuit DP is completed, the switching gate line GL(N+1) is at a low level, and then the gate line GL(2) is switched to a high level to correspond to the pixel column R(2). The pixel circuit P is charged. According to the above rule, the pixel circuits P of the pixel columns R(1) to R(N) are sequentially entered into the light-emitting phase, and the display of the screen is completed.

In short, before the pixel circuit P of any of the pixel columns R(i) enters the light-emitting phase, the gate line GL(N+1) is switched to the high level to virtualize the virtual pixel column DR. The prime circuit DP is precharged. After the pre-charging step of the virtual pixel circuit DP is completed, the switching gate line GL(N+1) is at a low level, and then the gate line GL(i) is switched to a high level to correspond to the pixel column R(i). The pixel circuit P is charged. After the pixel circuit P of the pixel sequence R(i) is charged, the gate line GL(i) is switched to a low level, so that the pixel circuit P of the pixel column R(i) enters the light-emitting phase, and then the virtual phase is The virtual pixel circuit DP of the pixel sequence DR is precharged to prepare to drive the pixel circuit P of the next pixel column R(i+1).

In the embodiment of the present invention, before charging the pixel circuit P of the pixel columns R(1) to R(N), the virtual pixel circuit DP of the virtual pixel sequence DR is precharged to enable the source. The potential of the pole lines SL(1) to SL(M) can be charged to a level in advance. After the precharge step is completed, when the pixel circuits P of the pixel columns R(1) to R(N) are charged, the potentials of the source lines SL(1) to SL(M) are charged to the desired level. The time can be shortened, so that the source lines SL(1)~SL(M) can be charged to the required level during the charging time, so that the pixel circuit P can correctly display the corresponding gray level value in the lighting stage. Therefore, the embodiment of the invention can improve the display quality of the picture. Preferably, the precharge time PCT of the virtual pixel circuit DP is greater than the charging time CT of the pixel circuit P to maintain the illumination phase time length of the pixel circuit P, thereby avoiding display problems such as picture flicker.

In summary, the organic light emitting display device and the driving method of the present invention can charge the pixel circuit to the amount of power required to display the corresponding gray scale value before the pixel circuit enters the light emitting stage, so that the pixel circuit is in the light emitting stage. The corresponding grayscale value can be displayed correctly, thereby improving the display quality of the screen.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

100‧‧‧Organic light-emitting display device

110‧‧‧Source Driver

111(1)~111(M)‧‧‧ Current source

120‧‧‧gate driver

130‧‧‧pixel circuit area

DP‧‧‧ virtual pixel circuit

DR‧‧‧Virtual Picture Column

GL(1)~GL(N+1)‧‧‧ gate line

P‧‧‧ pixel circuit

R(1)~R(N)‧‧‧

SL(1)~SL(M)‧‧‧ source line

VA‧‧‧ display area

Claims (10)

An organic light emitting display (OLED) device includes: a plurality of pixel circuits, each of the pixel circuits being electrically connected to one of a plurality of current sources, and the pixel circuits Forming a plurality of pixel columns; and a plurality of dummy pixel circuits, each of the virtual pixel circuits being electrically connected to one of the current sources, and the virtual pixel circuits form a a virtual pixel column; wherein the current sources precharge the virtual pixel circuit of the virtual pixel sequence before the current sources charge the pixel circuits of one of the pixel columns. The organic light emitting display device of claim 1, wherein a precharge time corresponding to one of the virtual pixel columns is greater than a charging time of one of the corresponding pixel columns. The OLED device of claim 1, wherein the pixel circuits are located in a display area of the organic light emitting display device, and the virtual pixel circuit is located outside the display area away from the current sources. side. The organic light emitting display device of claim 1, wherein the current sources are a plurality of current mirror circuits. The OLED device of claim 1, wherein each of the pixel circuits and each of the virtual pixel circuits comprises a driving circuit, and each of the pixel circuits further comprises A light-emitting element. A driving method for an organic light emitting display (OLED) device, the organic light emitting display device having a plurality of pixel circuits and a plurality of dummy pixel circuits, wherein the pixel circuits form a plurality of pixels a pixel array, the pixel circuits form a virtual pixel column, the pixel circuits and the virtual pixel circuits are electrically connected to the plurality of current sources, and the driving method comprises: using the current sources The virtual pixel circuits of the virtual pixel columns are precharged; and the pixel circuits of one of the pixel columns are charged by the current sources. The driving method of claim 6, wherein a pre-charging time corresponding to one of the virtual pixel columns is greater than a charging time of one of the corresponding pixel columns. The driving method of claim 6, wherein the pixel circuits are located in a display area of the organic light emitting display device, and the virtual pixel circuits are located outside the display area away from one of the current sources. . The driving method of claim 6, wherein the current sources are complex Several current mirror circuits. The driving method of claim 6, wherein each of the pixel circuits and each of the virtual pixel circuits comprises a driving circuit, and each of the pixel circuits further comprises a light emitting element.