CN101556764A - Driving method of passive matrix organic electroluminescent diode display device - Google Patents

Abstract

The invention discloses a driving method of a passive matrix organic electroluminescent diode display device, which comprises a plurality of scanning lines and a plurality of signal lines, and comprises the following steps: (1) dividing the scanning lines into a plurality of groups, wherein the number of the groups is less than that of the scanning lines; (2) scanning the scanning lines of each group in sequence, wherein the scanning lines of the same group are simultaneously turned on or off; (3) scanning each scanning line in sequence; and (4) combining the scanning results of the step (2) and the step (3) to generate a display frame. The invention can reduce the maximum brightness of the passive matrix organic electroluminescent diode display device, thereby improving the luminous efficiency.

Description

Driving method of passive matrix organic electroluminescent diode display device

technical field

The invention discloses an organic electroluminescence diode display device, in particular to a driving method of a passive matrix organic electroluminescence diode display device capable of reducing power loss.

Background technique

The difference between an organic light emitting diode (OLED) display device and a liquid crystal display device is that the organic light emitting diode display device can generate self-illumination, and does not need a backlight module to generate light like a liquid crystal display device. The advantages of the organic electroluminescent diode display device are lightness, thinness, high chroma, high contrast, high response speed, and being able to be fabricated on a flexible substrate. It is a display device with great development potential in the future.

Organic electroluminescent diode display devices can be divided into passive (passive) matrix organic electroluminescent diode (Passive Matrix Organic Light Emitting Diode, PMOLED) display devices and active (active) matrix organic electroluminescent diode display devices according to the driving method Device (Active Matrix Organic Light Emitting Diode, AMOLED). Please refer to FIG. 1, which is a schematic diagram of a pixel of an active matrix organic electroluminescent diode display device. In each pixel, at least two thin film transistors (Thin Film Transistor, TFT) T1, T2 and a capacitor C are required. And an organic electroluminescent diode 50, and the driving capability of the thin film transistors T1 and T2 and the design of the compensation circuit must be considered, so the complexity and process cost of the active matrix organic electroluminescent diode display device will be increased.

On the other hand, the passive matrix organic electroluminescence diode display device does not need to manufacture the thin film transistors T1 and T2 in FIG. 1 , and the manufacturing process is relatively simple. Please refer to FIG. 2A , which is a schematic diagram of a passive matrix organic electroluminescent diode display device. The passive matrix OLED display device includes a set of anode lines (Anode Lines) 60 and a set of cathode lines (Cathode Lines) 70 . The anode lines 60 are driven by a group of column (Column) driving units 62 , and the cathode lines 70 are driven by a group of row (Row) driving units 72 . However, the passive matrix organic electroluminescent diode display device requires instantaneous high brightness. Please refer to FIG. 2B, which is a graph of the luminous efficiency and brightness (Brightness, also known as luminance) of the green fluorescent organic electroluminescent diode, wherein the luminous efficiency The unit is lumens/watt (lumens/watt, lm/W), and the unit of brightness is candela/per square meter (candela/meter ² , cd/m ² ). It can be seen from the graph that the brighter the brightness of the green fluorescent organic electroluminescent diode, the lower the luminous efficiency. Therefore, the passive matrix organic electroluminescent diode display device will have high power consumption, short service life (Lifetime) and cannot be applied to high resolution. Shortcomings.

With the rising awareness of energy saving and environmental protection, and the high production cost of active matrix organic electroluminescent diode display devices, how to reduce the cost of passive matrix organic electroluminescent diode display devices without affecting the color performance and display quality? Lower production cost and lower power loss are important issues for passive matrix organic electroluminescent diode display devices.

Therefore, it is necessary to improve the existing passive matrix organic electroluminescent diode display device.

Contents of the invention

To solve the above problems, the object of the present invention is to provide a driving method for a passive matrix organic electroluminescent diode display device, which can reduce power loss and increase the luminous efficiency of the organic electroluminescent diode.

In order to achieve the above object, the present invention adopts the following technical solution: a driving method of a passive matrix organic electroluminescent diode display device, the passive matrix organic electroluminescent diode display device includes a plurality of scanning lines and a plurality of signal lines, and its characteristics In that: the driving method comprises the following steps:

(1) dividing these scanning lines into several groups, wherein the number of these groups is smaller than the number of these scanning lines;

(2) Scanning the scanning lines of each group in sequence, wherein the scanning lines of the same group are turned on or off at the same time;

(3) scanning each scanning line in sequence; and

(4) Combining the scanning results of step (2) and step (3) to generate a display screen.

Compared with the prior art, the driving method of the passive matrix organic electroluminescent diode display device of the present invention divides the scanning lines of the display area into several groups, and then scans in two stages. In the first stage, each group is scanned, In the second stage, each scanning line is scanned sequentially. By splitting the display screen into two sub-pictures for driving, the power loss can be reduced, and the luminous efficiency of the organic electroluminescent diode can be increased, that is, the efficiency of the passive matrix organic electroluminescent diode display device can be increased.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Description of drawings

FIG. 1 is a schematic diagram of a pixel of an active matrix organic electroluminescent diode display device.

FIG. 2A is a schematic diagram of a passive matrix organic electroluminescent diode display device.

FIG. 2B is a graph of luminous efficiency and brightness of a green fluorescent organic electroluminescent diode.

FIG. 3 is a flowchart of a driving method of a passive matrix organic electroluminescent diode display device in a preferred embodiment of the present invention.

4 is a schematic diagram of a driving timing diagram and a display screen of a passive matrix organic electroluminescent diode display device in a preferred embodiment of the present invention.

FIG. 5 is a graph comparing the luminous efficiency and brightness of the green fluorescent organic electroluminescent diodes in the prior art and the present invention.

Detailed ways

The detailed description and technical content of the present invention are now described as follows in conjunction with the accompanying drawings. The following description of the embodiments refers to the accompanying figures to illustrate specific embodiments in which the invention can be practiced.

Please refer to Fig. 3 and Fig. 4, Fig. 3 is the flow chart of the driving method of the passive matrix organic electroluminescent diode display device in the preferred embodiment of the present invention, Fig. 4 is the passive matrix electroluminescent diode display device in the preferred embodiment of the present invention Schematic diagram of the driving timing chart (Driving Timing Chart) of the LED display device and the display screen. The passive matrix organic electroluminescent diode display device includes scan lines 1 to 10 and several signal lines (only the signal line 11 is shown). The scanning lines 1 to 10 can be regarded as a group of scanning electrodes, and the signal line 11 can be regarded as a group of signal electrodes. The passive matrix organic electroluminescent diode display device further includes a multi-layer organic layer (not shown) sandwiched between the scanning electrodes and Between the signal electrodes, a display picture is generated by driving the two sets of electrodes. The driving method includes the following steps:

Step (1), the scanning lines 1 to 10 are divided into several groups, the number of these groups is less than the number of scanning lines (i.e. 10), in this embodiment, 10 scanning lines are divided into K groups, Where 1<K<10;

Step (2), in sequence 1, scan the scanning lines of K groups sequentially, wherein the scanning lines of the same group are turned on or off at the same time, as shown in Figure 4, the box 70 represents the first The group is lit, and other groups are not lit; box 72 represents that the Kth group is lit, and other groups are not lit, and when the scanning lines in the same group are turned on, the same The minimum brightness in the scanning line of the group is used as a signal to light up (will be explained in more detail below);

Step (3), in sequence 2, scan the scanning lines 1 to 10 in sequence, and the scanning signal is to complement the scanning lines 1 to 10 to the required brightness (will be explained in more detail below), as shown in Figure 4 As shown, the box 74 represents that the scan electrode 2 is lit to make up to the required brightness, and the other scan lines are not lit; the block 76 represents that the scan line 8 is lit to make up to the required brightness, and the other scan lines are not lit. bright; and

Step (4), combine the scan results of step (2) and step (3) to generate a display frame 78 , that is, add the results of sequence 1 and sequence 2 to generate a frame display frame 78 .

Please refer to Figure 4 and Table 1 at the same time. Table 1 shows the measurement data of Figure 4 in the low-contrast screen.

Table 1

The time ratio (Time Ratio) and the gray level value (Grey Level, ie brightness) of the prior art in Table 1 respectively represent the time ratios occupied by scanning lines 1 to 10 in sequence and the gray levels required for scanning lines 1 to 10 value (brightness), that is, the numerical value of the existing drive technology. Scan lines 6 and 10 shown in the table are the lowest gray scale value (brightness) with a value of 300. If the technical solution of the present invention is not adopted according to the prior art, the time ratio of sequentially scanning each scanning line is 0.1 (i.e. 10%), and its power ratio (Power Ratio) is regarded as a benchmark, i.e. 100%. When adopting the technical scheme of the present invention, scan with the scan time of timing 1 accounting for 50% (i.e. 0.5) of the scanning time of (sequence 1+sequence 2), and select the minimum brightness in the scanning lines of the same group as the point Bright signals, that is, scanning lines 1 to 10 all give signals with a gray scale value (brightness) of 300. In the sequence 2, the scan lines 1 to 10 are scanned sequentially, and the scan signal is to complement each of the scan lines 1 to 10 to a required gray scale value (brightness). The grayscale value (brightness) required for scanning line 1 is 400, the grayscale value (brightness) in sequence 1 is already 300, and 100 is added in sequence 2 to make up to 400; the grayscale value (brightness) required for scanning line 6 is 300, the grayscale value (brightness) in sequence 1 is already 300, so there is no need to make up for it in sequence 2. The rest of the scan lines are supplemented to the required grayscale value (brightness) in the same manner as above, and will not be repeated here. After measurement, it can be obtained that the power ratio of the present invention is only 79.9% of that of the prior art, achieving the purpose of reducing power loss.

Please refer to Table 2 again. Table 1 shows the measurement data of Figure 4 in the high-contrast screen. Scanning line 1 shown in the prior art in Table 2 is the lowest gray scale value (brightness), and its value is 100. If the technical solution of the present invention is not adopted according to the prior art, the time ratio of sequentially scanning each scanning line is 0.1 (ie 10%), and its power consumption ratio is regarded as a benchmark, ie 100%. When adopting the technical scheme of the present invention, scan with the scanning time of timing 1 accounting for 20% (ie 0.2) of the scanning time of (sequence 1+sequence 2), and select the minimum grayscale value in the scanning lines of the same group (Brightness) As a signal of lighting, that is, a signal of a gray scale value (brightness) of 100 is given to all of the scanning lines 1 to 10 . In the sequence 2, the scan lines 1 to 10 are scanned sequentially, and the scan signal is to complement each of the scan lines 1 to 10 to a required gray scale value (brightness). The grayscale value (brightness) required for scanning line 1 is 100, and the grayscale value in timing sequence 1 is already 100, so there is no need to make up for it in timing sequence 2; the grayscale value required for scanning line 6 is 300, and the grayscale value in timing sequence 1 The value is already 100, add 200 in sequence 2 to make up to 300. The rest of the scan lines are supplemented to the required grayscale value (brightness) in the same manner as above, and will not be repeated here. After measurement, it can be obtained that the power ratio of the present invention is only 93.1% of that of the prior art, achieving the purpose of reducing power loss.

Table 2

Please refer to FIG. 5 , which is a graph comparing the luminous efficiency and brightness of the green fluorescent organic electroluminescent diode in the prior art and the present invention. Because the maximum luminance of the prior art is relatively high, the luminous efficiency is poor, as shown in point A, while the present invention has high luminous efficiency due to the reduction of the maximum luminance, as shown in point B.

Compared with the prior art, the driving method of the passive matrix organic electroluminescent diode display device of the present invention divides the scanning lines of the display area into several groups, and then scans in two stages. In the first stage, each group is scanned, In the second stage, each scanning line is scanned sequentially. By splitting the display screen into two sub-pictures for driving, the power loss can be reduced, and the luminous efficiency of the organic electroluminescent diode can be increased, that is, the efficiency of the passive matrix organic electroluminescent diode display device can be increased.

Although the present invention has been disclosed above with the embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall prevail as defined by the appended claims.

Claims (5)

1. A driving method for a passive matrix organic electroluminescent diode display device, the passive matrix organic electroluminescent diode display device comprising several scanning lines and several signal lines, characterized in that: the driving method comprises the following steps: (1) dividing these scanning lines into several groups, wherein the number of these groups is smaller than the number of these scanning lines; (2) Scanning the scanning lines of each group in sequence, wherein the scanning lines of the same group are turned on or off at the same time; (3) scanning each scanning line in sequence; and (4) Combining the scanning results of step (2) and step (3) to generate a display screen. 2. The driving method according to claim 1, characterized in that: in step (2), when the scanning lines in the same group are turned on, the minimum brightness among the scanning lines in the same group is selected as the lighting Signal. 3. The driving method according to claim 2, wherein in step (3), when scanning each scanning line sequentially, each scanning line is supplemented to the required brightness. 4. The driving method as claimed in claim 1, wherein the scanning lines are used to light up a plurality of pixels connected to the scanning lines. 5. The driving method as claimed in claim 1, wherein the signal lines are used to provide signals to a plurality of pixels connected to the signal lines.

Images