Pixel driving circuit, OLED display panel and display device

Abstract

The application discloses a pixel driving circuit, an OLED display panel and a display device. The pixel driving circuit comprises a data writing module, a driving module, a light emitting device and an anode potential control module. The data writing module is configured to provide a data voltage to the driving module under the control of a gate driving signal. The driving module is configured to drive a first light emitting device, a second light emitting device or a third light emitting device in the light emitting device to emit light. The anode potential control module is configured to write a voltage to the anode of each light emitting device. According to the technical scheme provided in the embodiment of the application, a pixel driving circuit is provided, and fewer transistors and capacitors are used in the pixel circuit, so that the pixel density of the display panel is improved.

Description

Technical Field

[0001] This invention generally relates to the field of display technology, and more particularly to pixel driving circuits and OLED display panels and display devices. Background Technology

[0002] In recent years, silicon-based microdisplays have been continuously developing towards higher PPI (Pixels Per Inch). Currently, traditional silicon-based OLED devices use a white OLED structure with a color filter. However, because white OLED devices are less efficient than RGB OLED devices, and the introduction of the color filter structure leads to a decrease in brightness, using an RGB OLED structure with individual sub-pixels arranged side-by-side can significantly improve brightness. However, the RGB OLED structure, with its three sub-pixels arranged side-by-side, makes it difficult to achieve ultra-high PPI.

[0003] like Figure 1 The diagram shows a driving circuit diagram of a sub-pixel structure arranged side by side in the prior art. This circuit structure includes six transistors and three capacitors, as well as four signal lines in addition to two power signal lines. Three sub-pixels can be displayed simultaneously, and each sub-pixel is independent of the others. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a pixel driving circuit, an OLED display panel, and a display device.

[0005] In a first aspect, a pixel driving circuit is provided, including a data writing module, a driving module, a light-emitting device group, and an anode potential control module.

[0006] The data writing module is used to provide data voltage to the drive module under the control of the gate drive signal;

[0007] The light-emitting device group includes a first light-emitting device, a second light-emitting device, and a third light-emitting device connected in series, wherein the cathode of the third light-emitting device is connected to the first voltage signal terminal VSS;

[0008] The driving module is used to drive the first, second, or third light-emitting device in the light-emitting device group to emit light;

[0009] The anode potential control module is used to write voltage into the anode of each light-emitting device.

[0010] In a second aspect, an OLED display panel is provided, including the pixel driving circuit described above. The OLED display panel includes pixels distributed in an array, and each pixel includes red sub-pixels, green sub-pixels, and blue sub-pixels, which are stacked in layers.

[0011] Thirdly, a display device is provided, including the aforementioned OLED display panel.

[0012] According to the technical solution provided in the embodiments of this application, by providing a pixel driving circuit, fewer transistors and capacitors are used in the provided pixel circuit, thereby improving the pixel density of the display panel. Attached Figure Description

[0013] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0014] Figure 1 This is a diagram of a pixel driving circuit in the prior art;

[0015] Figure 2 This is a schematic diagram of the sub-pixel setting structure in this embodiment;

[0016] Figure 3 This is a pixel driving circuit diagram in one embodiment;

[0017] Figure 4 for Figure 3 Timing diagram of pixel driving circuit;

[0018] Figure 5 This is a pixel driving circuit diagram in another embodiment;

[0019] Figure 6 for Figure 5 Timing diagram of pixel driving circuit;

[0020] Figure 7 This is a pixel driving circuit diagram in another embodiment;

[0021] Figure 8 for Figure 7 Timing diagram of pixel driving circuit. Detailed Implementation

[0022] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] This embodiment provides a pixel driving circuit, including a data writing module, a driving module, a light-emitting device group, and an anode potential control module.

[0025] The data writing module is used to provide data voltage to the drive module under the control of the gate drive signal;

[0026] The light-emitting device group includes a first light-emitting device, a second light-emitting device, and a third light-emitting device connected in series, wherein the cathode of the third light-emitting device is connected to the first voltage signal terminal VSS;

[0027] The driving module is used to drive the first, second, or third light-emitting device in the light-emitting device group to emit light;

[0028] The anode potential control module is used to write voltage into the anode of each light-emitting device.

[0029] like Figure 3 , Figure 5 , Figure 7 As shown, a specific structural diagram of a pixel circuit is provided, wherein the data writing module includes a first transistor, the gate of the first transistor is connected to a gate line, the first electrode of the first transistor is connected to a data signal terminal, and the second electrode of the first transistor is connected to the driving module;

[0030] The driving module includes a second transistor, the gate of which is connected to the data writing module, the first terminal of which is connected to the second voltage signal terminal VDD, and the second terminal of which is connected to the anode potential control module.

[0031] In this embodiment, the gate of the first transistor in the data writing module is connected to the gate line. Under the control of the gate signal, the data signal of the first electrode is written into the driving module, that is, written into the gate of the second transistor. Under the control of the data signal, the second transistor writes the second voltage signal VDD of the first electrode into the light-emitting unit, controlling the light emission of each light-emitting device in the light-emitting unit. The first light-emitting device is a red light-emitting device, the second light-emitting device is a green light-emitting device, and the third light-emitting device is a blue light-emitting device. The order of the three light-emitting devices connected in series can be changed and does not necessarily have to follow the figure shown.

[0032] Furthermore, it also includes a capacitor module, one end of which is connected to the first voltage signal terminal VSS, and the other end is connected to the gate of the driving module.

[0033] Furthermore, the anode potential control module is specifically used to write voltage into the anode of the light-emitting device under the control of the EM control signal terminal;

[0034] It also includes a cathode potential control module.

[0035] The cathode electrode control module is used to write voltage into the cathode of the light-emitting device under the control of the SW control signal terminal.

[0036] In this embodiment, an anode potential control module and a cathode potential control module are provided. The two modules control the anode potential and cathode potential of each light-emitting device in the light-emitting device respectively, so as to realize the light emission of each light-emitting device. The three light-emitting devices in this embodiment are time-division display.

[0037] Furthermore, the anode potential control module includes a third transistor and a fourth transistor.

[0038] The gate of the third transistor is connected to the first EM control signal line, the first electrode of the third transistor is connected to the anode of the first light-emitting device, and the second electrode of the third transistor is connected to the cathode of the first light-emitting device.

[0039] The gate of the fourth transistor is connected to the second EM control signal line, the first electrode of the fourth transistor is connected to the anode of the first light-emitting device, and the second electrode of the fourth transistor is connected to the cathode of the second light-emitting device.

[0040] The specific circuit diagram in this embodiment is as follows: Figure 3 As shown, the Figure 3 The circuit diagram shown uses six transistors and one capacitor. In addition to two power signal lines VSS and VDD, it also includes six signal lines Gate, Data, EM1, EM2, SW1, and SW2. Compared with the existing driving circuit, it reduces the number of capacitors, which can improve the pixel density of the display panel.

[0041] Specifically, two transistors, the third transistor and the fourth transistor, are used as switching transistors to control the anode of each light-emitting device. For example, when the third transistor and the fourth transistor are both in the open state under the control of the first EM control signal and the second EM control signal, the second transistor of the driving module writes the VDD voltage into the first light-emitting device, that is, the anode of the red light-emitting device shown in the figure. The specific process is explained in detail in the timing control process below.

[0042] Furthermore, the cathode potential control module includes a fifth transistor and a sixth transistor.

[0043] The gate of the fifth transistor is connected to the first SW control signal line, the first terminal of the fifth transistor is connected to the cathode of the first light-emitting device, and the second terminal of the fifth transistor is connected to the cathode of the third light-emitting device.

[0044] The gate of the sixth transistor is connected to the second SW control signal line, the first electrode of the sixth transistor is connected to the cathode of the second light-emitting device, and the sixth transistor is connected to the cathode of the third light-emitting device.

[0045] like Figure 3 The circuit diagram shown also includes a cathode potential control module, which uses two transistors, the fifth transistor and the sixth transistor, as switching transistors for cathode potential control. For example, when the fifth transistor and the sixth transistor are both in the open state under the control of the first SW control signal and the second SW control signal, respectively, the VSS voltage is written into the third light-emitting device, that is, the cathode of the red light-emitting device shown in the figure. The specific process is explained in detail in the timing control process below.

[0046] like Figure 4 As shown Figure 3 The timing control diagram of the circuit shows that the three light-emitting devices in this circuit are time-division multiplexed. When the gate signal line Gate is high, the first transistor writes the data signal Data into the gate of the driver module. The waveforms of the gate signal line Gate and the data signal line Data are the same. When the red light-emitting device needs to be lit, the third and fourth transistors are both in the open state under the control of the first EM control signal and the second EM control signal, respectively. The second transistor of the driver module writes the VDD voltage into the anode of the red light-emitting device. When the fifth and sixth transistors are both in the closed state under the control of the first SW control signal and the second SW control signal, respectively, the VSS voltage is written into the cathode of the red light-emitting device and the cathode of the green light-emitting device. At this time, the red light-emitting device lights up, while the green and blue light-emitting devices do not light up. When the green light-emitting device needs to be lit, the third transistor is turned off under the control of the first EM control signal. When the fourth transistor is in the open state under the control of the second EM control signal, the second transistor of the drive module writes the VDD voltage to the anode of the green light-emitting device. When the fifth transistor is in the open state under the control of the first SW control signal, and the sixth transistor is in the closed state under the control of the second SW control signal, the VSS voltage is written to the cathode of the green light-emitting device. At this time, the green light-emitting device emits light, while the red and blue light-emitting devices do not emit light. When it is necessary to light up the blue light-emitting device, the third transistor is in the closed state under the control of the first EM control signal, and the fourth transistor is in the closed state under the control of the second EM control signal. When the second transistor of the drive module writes the VDD voltage to the anode of the blue light-emitting device, the fifth transistor is in the open state under the control of the first SW control signal, and the sixth transistor is in the open state under the control of the second SW control signal. At this time, the VSS voltage is written to the cathode of the blue light-emitting device. At this time, the blue light-emitting device emits light, while the red and green light-emitting devices do not emit light.

[0047] like Figure 5 As shown, this embodiment also provides a pixel driving circuit diagram, wherein the anode potential control module includes a seventh transistor, an eighth transistor, and a ninth transistor;

[0048] The gate of the seventh transistor is connected to the third SW control signal line, the first terminal of the seventh transistor is connected to the anode of the first light-emitting device, and the second terminal of the seventh transistor is connected to the cathode of the first light-emitting device.

[0049] The gate of the eighth transistor is connected to the fourth SW control signal line, the first electrode of the eighth transistor is connected to the anode of the second light-emitting device, and the eighth transistor is connected to the cathode of the second light-emitting device.

[0050] The gate of the ninth transistor is connected to the fifth SW control signal line, the first electrode of the ninth transistor is connected to the anode of the third light-emitting device, and the second electrode of the ninth transistor is connected to the cathode of the third light-emitting device.

[0051] Should Figure 5 The circuit diagram shown uses five transistors and one capacitor. In addition to the two power signal lines VSS and VDD, it also includes five signal lines Gate, Data, SW3, SW4, and SW5. Compared with the existing driving circuit, it reduces one transistor and two capacitors, which can improve the pixel density of the display panel.

[0052] The anode potential control module in this embodiment can also control the cathode voltage, such as... Figure 6 As shown Figure 5The timing control diagram of the circuit shows that the three light-emitting devices in this circuit are time-division multiplexed. When the gate signal line Gate is high, the first transistor writes the data signal Data into the gate of the driver module. The waveforms of the gate signal line Gate and the data signal line Data are the same. When the red light-emitting device needs to be lit, the seventh transistor is in the open state under the control of the third SW control signal, while the eighth and ninth transistors are in the closed state under the control of the fourth and fifth SW control signals. At this time, the second transistor of the driver module writes the VDD voltage into the anode of the red light-emitting device and the VSS voltage into the cathode of the red light-emitting device. At this time, the red light-emitting device emits light, while the green and blue light-emitting devices do not emit light. When the green light-emitting device needs to be lit, the eighth transistor is in the closed state under the control of the fourth SW. When the green LED is in the ON state under the control of the signal, the seventh and ninth transistors are in the OFF state under the control of the third and fifth SW control signals. At this time, the second transistor of the drive module writes the VDD voltage to the anode of the green LED and the VSS voltage to the cathode of the green LED. At this time, the green LED emits light, while the red and blue LEDs do not emit light. When it is necessary to light up the green and blue LEDs, the ninth transistor is in the ON state under the control of the fifth SW control signal, and the seventh and eighth transistors are in the OFF state under the control of the third and fourth SW control signals. At this time, the second transistor of the drive module writes the VDD voltage to the anode of the blue LED and the VSS voltage to the cathode of the blue LED. At this time, the blue LED emits light, while the green and red LEDs do not emit light.

[0053] like Figure 7 As shown, this embodiment also provides a pixel driving circuit, wherein the anode potential control module includes a tenth transistor and an eleventh transistor;

[0054] The gate of the tenth transistor is connected to the sixth SW control signal line, the first terminal of the tenth transistor is connected to the second terminal of the driving module, and the tenth transistor is connected to the anode of the first light-emitting device.

[0055] The gate of the eleventh transistor is connected to the seventh SW control signal line, the first terminal of the eleventh transistor is connected to the second terminal of the driving module, and the second terminal of the eleventh transistor is connected to the anode of the third light-emitting device.

[0056] Should Figure 7 The circuit diagram shown uses four transistors and one capacitor. In addition to the two power signal lines VSS and VDD, it also includes four signal lines Gate, Data, SW6, and SW7. Compared with the existing driving circuit, it reduces the number of transistors and capacitors, which can improve the pixel density of the display panel.

[0057] Specifically, two transistors, the tenth and eleventh transistors, are used as switching transistors to control the anode of each light-emitting device, such as... Figure 8 As shown Figure 7 The timing control diagram of the circuit shows that when the tenth transistor is in the off state under the control of the sixth SW control signal and the eleventh transistor is in the on state under the control of the seventh SW control signal, the second transistor of the drive module writes the VDD voltage into the anode of the red light-emitting device. Alternatively, when the tenth transistor is in the on state under the control of the sixth SW control signal and the eleventh transistor is in the off state under the control of the seventh SW control signal, the second transistor of the drive module writes the VDD voltage between the anode of the blue light-emitting device and the cathode of the green light-emitting device.

[0058] Furthermore, the cathode of the first light-emitting device is connected to the first voltage signal terminal VSS.

[0059] In this embodiment, the first and second light-emitting devices are directly connected to VSS via a wire. When the anode of the red light-emitting device is written with VDD voltage, the cathode of the red light-emitting device is at VSS voltage, and the red light-emitting device emits light. When the anode of the blue light-emitting device is written with a positive VDD voltage, the blue light-emitting device emits light. When the anode of the blue light-emitting device is written with a negative VDD voltage, the green light-emitting device emits light. In this embodiment, when the gate signal line Gate is high, the first transistor writes the data signal Data to the gate of the driving module. The data signal line is written with a negative voltage when the green light-emitting device emits light.

[0060] In specific embodiments, the aforementioned transistors can be thin-film transistors (TFTs) or metal-oxide-semiconductor field-effect transistors (MOSs), and are not limited thereto. The first and second terminals of these transistors can be either the first or second terminals of the transistor, and their functions can be interchanged depending on the type of transistor, etc.

[0061] This embodiment also provides an OLED display panel, including the pixel driving circuit described above. The OLED display panel includes pixels distributed in an array, and each pixel includes red sub-pixels, green sub-pixels, and blue sub-pixels, which are stacked in layers.

[0062] In this embodiment, the originally side-by-side subpixels are changed to a stacked arrangement, with three subpixels stacked together. This increases the pixel density of the display panel, up to three times the original density. The position of the stacked subpixels is unrestricted, such as... Figure 2 As shown, from top to bottom are red sub-pixels, green sub-pixels, and blue sub-pixels. These can actually be swapped without affecting the above effect.

[0063] In this embodiment, the sub-pixels emit light to form different colors. Therefore, in order to ensure the light emission effect, a transparent metal layer is set between adjacent sub-pixels, an ITO backplate is set below the sub-pixels, and an ITO or IZO structure is set above them.

[0064] The pixel driving circuit in this embodiment controls the light emission of three sub-pixels in series, which can reduce the number of transistors and capacitors in the pixel driving circuit and increase the pixel density of the display panel.

[0065] This embodiment also provides a display device, including the above-described OLED display panel.

[0066] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A pixel driving circuit, characterized in that, It includes a data writing module, a driver module, a light-emitting device group, an anode potential control module, and a capacitor module. The data writing module is used to provide data voltage to the drive module under the control of the gate drive signal; The light-emitting device group includes a first light-emitting device, a second light-emitting device, and a third light-emitting device connected in series. The cathode of the third light-emitting device is connected to a first voltage signal terminal VSS. The first light-emitting device, the second light-emitting device, and the third light-emitting device are any one of a red sub-pixel, a green sub-pixel, and a blue sub-pixel. The red sub-pixel, the green sub-pixel, and the blue sub-pixel are stacked. The driving module is used to drive the first, second, or third light-emitting device in the light-emitting device group to emit light; The anode potential control module is used to write voltage into the anode of each light-emitting device; the anode potential control module includes a tenth transistor and an eleventh transistor; The gate of the tenth transistor is connected to the sixth SW control signal line, the first terminal of the tenth transistor is connected to the second terminal of the driving module, and the tenth transistor is connected to the anode of the first light-emitting device. The gate of the eleventh transistor is connected to the seventh SW control signal line, the first terminal of the eleventh transistor is connected to the second terminal of the driving module, and the second terminal of the eleventh transistor is connected to the anode of the third light-emitting device. The cathode of the first light-emitting device is directly connected to the first voltage signal terminal VSS via a wire; One end of the capacitor module is connected to the first voltage signal terminal VSS, and the other end is connected to the gate of the driving module. When a positive voltage VDD is written to the anode of the third light-emitting device, the third light-emitting device emits light. When the anode of the third light-emitting device is written with a negative voltage VDD, the second light-emitting device emits light, and the data signal line is written with a negative voltage when the second light-emitting device emits light.

2. The pixel driving circuit according to claim 1, characterized in that, The data writing module includes a first transistor, the gate of the first transistor is connected to a gate line, the first electrode of the first transistor is connected to a data signal terminal, and the second electrode of the first transistor is connected to the driving module. The driving module includes a second transistor, the gate of which is connected to the data writing module, the first terminal of which is connected to the second voltage signal terminal VDD, and the second terminal of which is connected to the anode potential control module.

3. An OLED display panel, characterized in that, The OLED display panel includes the pixel driving circuit of claim 1 or 2, and the pixel includes an array of pixels, the pixels including red sub-pixels, green sub-pixels and blue sub-pixels.

4. A display device, characterized in that, Including the OLED display panel as described in claim 3.

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