CN1332370C - Digital driving method and device for active organic light emitting diode display - Google Patents

Abstract

A digital driving method and device for active organic light emitting diode Display is prepared as connecting Organic Light Emitting Diode (OLED) of each Pixel device to zero potential (GND) to make organic light emitting diode not be able to be lighted when image data is inputted, connecting potential of power line to positive potential to make organic light emitting diode be lighted when image data is outputted.

Description

Digital driving method and device for active organic light emitting diode display

technical field

The present invention relates to a digital driving method and device for an active organic light emitting diode display, especially a digital driving architecture that controls the potential level of a power line to realize writing and lighting separation.

Background technique

It is known that the current technology of TFT is divided into two types: amorphous silicon (a-Si TFT) and polycrystalline silicon (Poly-SiTFT). The so-called TFT-LCD refers to amorphous silicon (a-Si TFT). It is the mainstream product of LCD. The biggest difference between low-temperature polysilicon (LTPS TFT) and a-SiTFT is that LTPS transistors need to undergo further laser tempering process steps to convert the amorphous silicon film into a polysilicon film layer, making LTPS a silicon crystal structure. -Si TFT is arranged in an orderly manner, so the electron conduction rate can be increased to 200cm2/V-sec. LTPS technology can make the components smaller, reduce the overall TFT component area by more than 50%; and increase the aperture ratio (aperture ratio), compared with a-Si TFT, it can produce higher resolution under the same size, and Reduce power consumption; in the design, the driver module can be directly integrated on the glass substrate (System on Glass), and part of the Driver IC can be integrated into the glass substrate, which is beneficial to reduce the area required for the circuit board and the number of components and the driver IC The connection between the panel electrode and the panel electrode can reduce the cost of materials, and at the same time, it can avoid product damage caused by assembly during the assembly process of the back-end module, thereby improving the yield rate and reducing the manufacturing cost; in addition, due to the integrated part The use of Driver IC, in addition to reducing the weight of the IC, can also reduce other materials required for subsequent assembly, and the overall weight will be greatly reduced. Because low-temperature polysilicon (LTPS TFT) still has the advantages of power saving, high brightness, fine picture, thin and light, and fewer contacts (less than 200 contacts, which can help improve yield rate, a-Si TFT is more than 3842 contacts).

However, since the thin film transistors manufactured by the low temperature polysilicon (LTPS) process will vary in characteristics, when the driving system uses analog (ANALOG) modulation to express gray scales, it is often because the thin film transistors (TFT) After undergoing the process steps of laser tempering, there are different characteristics. Even if the same voltage signal is written, the OLEDs of different pixels generate different currents and emit different luminances. This phenomenon will cause the OLED panel to display images with wrong gray scales, which seriously damages the image uniformity (Image Uniformity).

Contents of the invention

Therefore, the main purpose of the present invention is to solve the above-mentioned traditional deficiency and avoid the existence of the deficiency. The present invention uses a digital drive architecture that controls the potential level of the power supply line to realize writing and lighting separation.

In order to achieve the above object, the digital driving method and device of the active organic light emitting diode display of the present invention are mainly composed of multiple groups of pixel (pixel) devices, and the organic light emitting diode (OLED) of each pixel device is used for common cathode The grounding method uses the control of the potential of the power line to realize the digital drive architecture of Program DisplaySeparated (Program DisplaySeparated). When inputting image data, the potential of the power line is connected to the zero potential (GND), so that the organic light-emitting diode cannot emit light. When the image data is output, the potential of the power line is connected to the positive potential to make the organic light emitting diode light up.

Description of drawings

Relevant detailed content and technical specification of the present invention, now cooperate accompanying drawing to illustrate as follows:

FIG. 1-1 is a schematic diagram of a single pixel device of an active OLED display according to the first embodiment of the present invention.

Figure 1-2 is a timing diagram of the driving voltage waveform in Figure 1-1.

Fig. 2-1 is a schematic diagram of the second embodiment of the present invention.

Figure 2-2 is a timing diagram of the driving voltage waveform in Figure 2-1.

Fig. 3-1 is a schematic diagram of the third embodiment of the present invention.

Figure 3-2 is a timing diagram of the driving voltage waveform in Figure 3-1.

Detailed ways

Please refer to FIGS. 1-1 and 1-2 , which are schematic diagrams of a single pixel device of an active OLED display according to the first embodiment of the present invention and the timing diagram of driving voltage waveforms in FIG. 1-1 . As shown in the figure: the digital driving method and device of the active organic light emitting diode display of the present invention are mainly composed of multiple sets of pixel (pixel) devices 10, and the organic light emitting diode (OLED) 4 of each pixel device 10 The common cathode grounding method is used to control the potential level of the power line 7 to realize the digital drive architecture of writing luminous separation (Program DisplaySeparated). When inputting image data, the potential of the power line 7 is connected to zero potential (GND), so that The organic light emitting diode 4 cannot be illuminated. When outputting image data, the potential of the power line 7 is connected to the positive potential VH, so that the organic light emitting diode 4 is illuminated.

In order to realize the above method, the pixel (pixel) device 10 adopted in the present invention includes: a switch unit 1, a drive unit 2, a storage unit 3 and an organic light emitting diode (OLED) 4; wherein,

The above-mentioned switch unit 1 can be a P-channel thin film transistor (TFT), and the two input terminals 11 and 12 of the switch unit 1 are connected to a scan line (Scan Line) 5 and a data line (Data Line) 6 respectively;

The drive unit 2 can be a P-channel thin film transistor (TFT), the input terminal 21 of the drive unit 2 is connected to the power supply line (SUPPLY LINE) 7, and the input terminal 22 of the other end is connected to the output terminal 13 of the above-mentioned switch unit 1;

The storage unit 3 is composed of a capacitor, one end is grounded, and the other end is connected to the connection between the output end 13 of the switch unit 1 and the input end 22 of the drive unit 2;

The input terminal 41 of the organic light emitting diode (OLED) 4 is connected to the output terminal 23 of the driving unit 2, and the output terminal 42 of the organic light emitting diode (OLED) 4 is grounded;

When the device is scanning image data, the potential of the power line 7 is connected to the zero potential GND, so that the organic light emitting diode 4 cannot be illuminated, and the switch unit 1 is in a conductive state. At this time, the image data enters the switch unit through the data line 6 1, after being scanned by the scanning line 5, it is stored in the storage unit 3 (it is also charged to the storage unit after the switch unit is turned on), and if the image data is bright, the zero voltage GND is stored in the storage unit 3, if If the image data is not illuminated, the positive voltage VH is stored in the storage unit 3; during the scanning process, the potential of the scanning line is zero potential GND, and the potentials of other scanning lines are positive potential VH. After all scanning operations are completed, The potential of the power line 7 is connected to the positive potential VH, so that the organic light emitting diode 4 of the pixel device 10 storing the zero voltage GND in the storage unit 3 lights up.

Please refer to FIGS. 2-1 and 2-2, which are schematic diagrams of the second embodiment of the present invention and the timing diagram of the driving voltage waveform in FIG. 2-1. As shown in the figure: the digital driving method and device of the active organic light emitting diode display of the present invention are mainly composed of multiple groups of pixel (pixel) devices 20, and the organic light emitting diode (OLED) 4 of each pixel device 20 The common cathode grounding method is used to control the potential level of the power line 7 to realize the digital drive architecture of writing luminous separation (Program Display Separated). When inputting image data, the potential of the power line 7 is connected to zero potential (GND). The organic light emitting diode 4 cannot be illuminated, and when outputting image data, the potential of the power line 7 is connected to the positive potential VH, so that the organic light emitting diode 4 is illuminated.

In order to realize the above method, the pixel (pixel) device 20 adopted in the present invention includes: a switch unit 1, a drive unit 2, a storage unit 3 and an organic light emitting diode (OLED) 4; wherein,

The above-mentioned switch unit 1 can be a P-channel thin film transistor (TFT), and the two input terminals 11 and 12 of the switch unit 1 are connected to a scan line (Scan Line) 5 and a data line (Data Line) 6 respectively;

The drive unit 2 can be a thin film transistor (TFT) of P channel, the input end of the drive unit 2 is connected to the power supply line (SUPPLY LINE) 7 with the connection 21, and the input end 22 of the other end is connected with the output end 13 of the above-mentioned switch unit 1 ;

The storage unit 3 is composed of a capacitor, one end is connected to the power line 7, and the other end is connected to the connection between the output end 13 of the switch unit 1 and the input end 22 of the drive unit 2;

The input terminal 41 of the organic light emitting diode (OLED) 4 is connected to the output terminal 23 of the driving unit 2, and the output terminal 42 of the organic light emitting diode (OLED) 4 is grounded;

When the device is scanning image data, the potential of the power line 7 is connected to the zero potential GND, so that the organic light emitting diode 4 cannot be illuminated, and the switch unit 1 is in a conduction state. At this time, the image data enters the switch unit through the data line 6 1, after being scanned by the scanning line 5, it is stored in the storage unit 3 (which is also to charge the storage unit after the switch unit is turned on), and if the image data is bright, the negative voltage VL is stored in the storage unit 3, if If the image data is not illuminated, the zero voltage GND is stored in the storage unit 3; the potential of the scanning line during the scanning process is a negative potential VL, and the potential of other scanning lines is a positive potential VH. After all scanning operations are completed, The potential of the power line 7 is connected to the positive potential VH, so that the organic light emitting diode 4 of the pixel device 20 storing the negative voltage VL in the storage unit 3 lights up.

Please refer to FIGS. 3-1 and 3-2 , which are schematic diagrams of a single pixel device of an active OLED display according to a third embodiment of the present invention and the timing diagram of driving voltage waveforms in FIG. 3-1 . As shown in the figure: the digital driving method and device of the active organic light emitting diode display of the present invention are mainly composed of multiple sets of pixel (pixel) devices 30, 40, and the organic light emitting diode (OLED) of each pixel device 30, 40 )4 adopts the common cathode grounding method, and uses the control power line 7 potential level to realize the digital drive architecture of writing luminous separation (Program Display Separated). When inputting image data, connect the power line 7 potential to zero potential (GND) , so that the organic light emitting diode 4 cannot be illuminated, and when outputting image data, the potential of the power line 7 is connected to the positive potential VH, so that the organic light emitting diode 4 is illuminated.

In order to realize the above method, the pixel (pixel) device 30 used in the present invention includes: a switch unit 1, a drive unit 2, a storage unit 3 and an organic light emitting diode (OLED) 4; wherein,

The above-mentioned switch unit 1 can be a P-channel thin film transistor (TFT), and the two input terminals 11 and 12 of the switch unit 1 are connected to a scan line (Scan Line) 5 and a data line (Data Line) 6 respectively;

The drive unit 2 can be a thin film transistor (TFT) of P channel, the input end of the drive unit 2 is connected to the power supply line (SUPPLY LINE) 7 with the connection 21, and the input end 22 of the other end is connected with the output end 13 of the above-mentioned switch unit 1 ;

The storage unit 3 is composed of a capacitor, one end is connected to the connection between the output end 13 of the switch unit 1 and the input end 22 of the drive unit 2, and the other end is connected to the scanning line 8 of the adjacent pixel device 40;

The input terminal 41 of the organic light emitting diode (OLED) 4 is connected to the output terminal 23 of the driving unit 2, and the output terminal 42 of the organic light emitting diode (OLED) 4 is grounded;

When the device is scanning image data, the potential of the power line 7 is connected to the zero potential GND, so that the organic light emitting diode 4 cannot be illuminated, and the switch unit 1 is in a conduction state. At this time, the image data enters the switch unit through the data line 6 1, after being scanned by the scanning line 5, it is stored in the storage unit 3 (it is also charged to the storage unit after the switch unit is turned on), and if the image data is bright, the zero voltage GND is stored in the storage unit 3, if If the image data is not illuminated, the positive voltage VH is stored in the storage unit 3; during the scanning process, the potential of the scanning line is zero potential GND, and the potentials of other scanning lines are positive potential VH. After all scanning operations are completed, The potential of the power line 7 is connected to the positive potential VH, so that the organic light emitting diode 4 of the pixel device 30 storing the zero voltage GND in the storage unit 3 lights up.

The foregoing are only preferred embodiments of the present invention, and are not intended to limit the implementation scope of the present invention. That is, all equivalent changes and modifications made according to the patent scope of the present invention are covered by the patent scope of the present invention.

Claims (10)

1. A digital drive device for an active organic light emitting diode display, the display is composed of a plurality of pixel devices (10), characterized in that each pixel device (10) comprises: A switch unit (1) has two input terminals (11), (12) and an output terminal (13) on it, and the two input terminals (11), (12) are respectively connected to the data line (6) and the scanning line ( 5); A driving unit (2) has two input terminals (21), (22) and an output terminal (23) on it, and these two input terminals (21), (22) are respectively connected with the above-mentioned power line (7) and the above-mentioned switch The output terminal (13) of unit (1) is connected; A storage unit (3), one end of which is grounded, and the other end is connected to the connection between the output end (13) of the switch unit (1) and the input end (22) of the drive unit (2); An organic light emitting diode (4), which has an input terminal (41) and an output terminal (42), the input terminal (41) is connected to the output terminal (23) of the driving unit (2), and the output terminal (42) ) to ground; When the pixel device (10) is scanning image data, the potential of the power line (7) is connected to zero potential, so that the organic light-emitting diode (4) cannot be illuminated, and the switch unit (1) is in a conducting state. The data enters the switch unit (1) through the data line, and is stored in the storage unit (3) after being scanned by the scanning line (5). If the image data is bright, zero voltage is stored in the storage unit (3) , if the image data is not bright, then store a positive voltage in the storage unit (3), after all the scanning operations are completed, connect the potential of the power line (7) to the positive potential, so that zero voltage is stored in the storage unit ( 3) The organic light-emitting diodes of the pixel device (10) light up (4). 2. The digital driving device of an active organic light emitting diode display according to claim 1, wherein the potential of the scanning line (5) during the scanning process is zero potential, and the potential of other scanning lines (5) is positive potential . 3. The digital driving device of an active organic light emitting diode display according to claim 1, characterized in that the switching unit (1) and the driving unit (2) can be P-channel thin film transistors (TFTs). 4. The digital driving device of an active OLED display according to claim 1, wherein the storage unit (3) is formed by a capacitor. 5. A digital driving method for an active organic light emitting diode display, the display is composed of a plurality of pixel devices (20), wherein each pixel device (20) includes: A switch unit (1) has two input terminals (11), (12) and an output terminal (13) on it, and the two input terminals (11), (12) are respectively connected to the data line (6) and the scanning line ( 5); A driving unit (2) has two input terminals (11), (12) and an output terminal (13) on it, and these two input terminals (11), (12) are respectively connected with the above-mentioned power line (7) and the above-mentioned switch The output terminal (13) of unit (1) is connected; A storage unit (3), one end of which is connected to the power line (7), and the other end is connected to the connection between the output terminal (13) of the switch unit (1) and the input terminal (22) of the drive unit (2); An organic light emitting diode (4), which has an input terminal (41) and an output terminal (42), the input terminal (41) is connected to the output terminal (23) of the driving unit (2), and the output terminal (42) ) to ground; It is characterized in that: when the pixel device (20) is scanning image data, the potential of the power line (7) is connected to zero potential, so that the organic light emitting diode (4) cannot be illuminated, and the switch unit (1) is in a conducting state At this time, the image data enters the switch unit (1) through the data line (6), and is stored in the storage unit (3) after being scanned by the scanning line (5). If the image data is bright, a negative voltage is stored In the storage unit (3), if the image data is not bright, then store zero voltage in the storage unit (3), after all scanning operations are completed, the potential of the power line (7) is connected to a positive potential, so that The organic light emitting diode (4) of the pixel device (20) storing the negative voltage in the storage unit (3) lights up. 6. The digital driving method of an active organic light emitting diode display according to claim 5, characterized in that the potential of the scanning line (5) during the scanning process is a negative potential, and the potentials of other scanning lines (5) are positive potential. 7. A digital driving device for an active organic light emitting diode display, the display is composed of a plurality of pixel devices (30), (40), characterized in that each pixel device (30), (40) includes: A switch unit (1) has two input terminals (11), (12) and an output terminal (13) on it, and the two input terminals (11), (12) are respectively connected to the data line (6) and the scanning line ( 5); A driving unit (2) has two input terminals (21), (22) and an output terminal (23) on it, and these two input terminals (21), (22) are respectively connected with the above-mentioned power line (7) and the above-mentioned switch The output terminal (13) of unit (1) is connected; A storage unit (3), one end of which is connected to the connection between the output end (13) of the above-mentioned switch unit (1) and the input end (22) of the drive unit (2), and the other end is connected to the adjacent pixel device (40) scanline(8); An organic light emitting diode (4) has an input terminal (41) and an output terminal (13) on it, the input terminal (41) is connected with the output terminal (23) of the drive unit (2), and the output terminal (42 ) to ground; When the pixel devices (30), (40) are scanning image data, the potential of the power line (7) is connected to zero potential, so that the organic light emitting diode (4) cannot be illuminated, and the switch unit (1) is in a conducting state At this time, the image data enters the switch unit (1) through the data line (6), and is stored in the storage unit (3) after being scanned by the scanning line (5). If the image data is bright, zero voltage is stored In the storage unit (3), if the image data is not bright, store a positive voltage in the storage unit (3), and after completing all scanning operations, connect the potential of the power line (7) to a positive potential, so that The organic light emitting diode (4) of the pixel device (30) storing the zero voltage in the storage unit (3) lights up. 8. The digital drive device for an active organic light emitting diode display according to claim 7, characterized in that the potential of the scanning line (5) during the scanning process is zero potential, and the potential of other scanning lines (5) is positive potential . 9. A digital driving method for an active organic light-emitting diode display, which is mainly composed of multiple groups of pixel devices (30), (40), and is characterized in that when each pixel device (30), (40) inputs image data , connect the potential of the power line (7) to zero potential, so that the organic light emitting diode (4) cannot be illuminated; when outputting image data, connect the potential of the power line (7) to a positive potential, so that the organic light emitting diode (4) ) light up. 10. The digital driving method of an active organic light emitting diode display according to claim 7, characterized in that the organic light emitting diode (OLED) (4) of each pixel device (30), (40) can be grounded with a common cathode Way.

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