CN111883042B - Display panel and display device - Google Patents

Abstract

The embodiment of the invention discloses a display panel and a display device. The display panel includes a plurality of light emitting units including light emitting devices and corresponding pixel circuits thereof, and the display panel includes: a first power line, a second power line, and an initialization signal line; each pixel circuit is respectively connected to the first power line, the second power line and the initialization signal line, and comprises a driving transistor, wherein the driving transistor and the light emitting device are sequentially connected between the first power line and the second power line; in the off-screen display mode, the voltage transmitted to the first electrode of the driving transistor in the pixel circuit by the first power line is equal to the absolute value of the voltage on the initializing signal line, and the voltage transmitted to the second electrode of the light emitting device corresponding to the pixel circuit by the second power line is larger than the voltage in the non-off-screen display mode. According to the technical scheme, the power consumption of the screen-extinguishing display mode of the display device is reduced, so that the standby time of the display device is prolonged, and the user experience is improved.

Description

Display panel and display device

Technical Field

The embodiment of the invention relates to the technical field of display, in particular to a display panel and a display device.

Background

In order to still view information in a standby mode, the conventional display device introduces a screen-off mode (Always on display, AOD), only a partial area of a screen is displayed in the AOD mode, a driving chip is in an idle state, basic information can be viewed without waking up equipment, and power consumption can be saved compared with a mode of waking up equipment to view information.

However, the power consumption of the current AOD mode is still higher, which shortens the standby time of the display device and affects the user experience.

Disclosure of Invention

The invention provides a display panel and a display device, which are used for reducing power consumption generated when the display device works in a screen-off display mode and prolonging the standby time of the display device.

In a first aspect, an embodiment of the present invention provides a display panel including a plurality of light emitting units, each of the light emitting units including a light emitting device and a corresponding pixel circuit thereof, the display panel including:

a first power line, a second power line, and an initialization signal line;

each of the pixel circuits is connected to the first power supply line, the second power supply line, and the initialization signal line, respectively; in each of the light emitting units, the pixel circuit includes a driving transistor, the driving transistor and the light emitting device being sequentially connected between the first power line and the second power line;

In the off-screen display mode, the voltage transmitted to the first electrode of the driving transistor in the pixel circuit by the first power line is equal to the absolute value of the voltage on the initialization signal line, and the voltage transmitted to the second electrode of the light emitting device corresponding to the pixel circuit by the second power line is greater than the voltage in the off-screen display mode.

Optionally, in the off-screen display mode, a voltage transmitted to the second electrode of the light emitting device corresponding to the pixel circuit by the second power line is equal to a voltage on the initialization signal line.

Optionally, in the off-screen display mode, a voltage transmitted to the second electrode of the light emitting device corresponding to the pixel circuit by the second power line is equal to a ground voltage.

In a second aspect, an embodiment of the present invention provides a display apparatus including a display panel and a driving chip;

the display panel includes a plurality of light emitting units, each of the light emitting units including a light emitting device and a corresponding pixel circuit thereof, the display panel further including: a first power line, a second power line, and an initialization signal line;

each of the pixel circuits is connected to the first power supply line, the second power supply line, and the initialization signal line, respectively; in each of the light emitting units, the pixel circuit includes a driving transistor, the driving transistor and the light emitting device being sequentially connected between the first power line and the second power line;

The driving chip comprises a first power supply output end, a second power supply output end and an initialization signal output end which are respectively connected with the first power supply line, the second power supply line and the initialization signal line; the first power line transmits the voltage output by the first power output end to a first pole of the driving transistor in the pixel circuit, and the second power line transmits the voltage output by the second power output end to a second pole of the light emitting device corresponding to the pixel circuit;

the driving chip is used for outputting voltage which is equal to the absolute value of the voltage which is output by the initialization signal output end through the first power output end in the screen-off display mode, and outputting voltage which is larger than the voltage which is output by the second power output end in the screen-off display mode.

Optionally, the driving chip includes an inverter and a first switch, and the initialization signal output end is connected to the first power output end through the inverter and the first switch.

Optionally, the driving chip further includes a second switch, and the initialization signal output end is connected to the second power output end through the second switch.

Optionally, the driving chip further includes a third switch, and the initialization signal output end is grounded through the third switch.

Optionally, the driving chip further includes a power signal generating circuit connected to the first power output end and the second power output end, where the power signal generating circuit is configured to generate a first power signal in a non-off-screen display mode and output the first power signal through the first power output end, and generate a second power signal and output the second power signal through the second power output end;

the driving chip is also used for controlling the power supply signal generating circuit to stop working in a screen-off display mode.

Optionally, the driving chip further includes an initialization signal generating circuit connected to the initialization signal output end for generating an initialization signal;

the inverter comprises a first transistor and a second transistor, wherein the control ends of the first transistor and the second transistor are connected with each other, the first end of the first transistor and the first end of the second transistor are connected to the initialization signal generating circuit, the second end of the first transistor is connected with the second end of the second transistor and the first end of the first switch, and the second end of the first switch is connected with the first power supply output end;

The driving chip is also used for controlling the first transistor, the second transistor and the first switch in a screen-off display mode and outputting an initialization signal generated by the initialization signal generating circuit to the first power supply output end;

preferably, the channel types of the first transistor and the second transistor are different;

preferably, the first switch comprises a diode.

Optionally, the driving chip further includes an initialization signal generating circuit connected to the initialization signal output end for generating an initialization signal;

the second switch comprises a third transistor, a first end of the third transistor is connected with the initialization signal generation circuit, and a second end of the third transistor is connected with the second power supply output end;

the driving chip is also used for controlling the third transistor in a screen-off display mode, and outputting the initialization signal generated by the initialization signal generating circuit to the second power supply output end through the third transistor.

Optionally, the third switch includes a fourth transistor, a first end of the fourth transistor is grounded, and a second end of the fourth transistor is connected to the second power output end;

The driving chip is also used for controlling the fourth transistor in a screen-off display mode, and outputting a grounding signal to the second power supply output end through the fourth transistor.

In the display panel and the display device provided by the embodiments of the invention, in the off-screen display mode, the voltage on the first power line connected with the pixel circuit is set to be equal to the absolute value of the voltage on the initialization signal line, so that the voltage transmitted to the first pole of the driving transistor by the first power line is smaller than the voltage of the driving transistor in the non-off-screen display mode, the voltage on the second power line connected with the pixel circuit is set to be larger than the voltage of the driving transistor in the non-off-screen display mode, so that the voltage transmitted to the second pole of the light emitting device by the second power line is smaller than the voltage of the light emitting device in the non-off-screen display mode, the voltage difference between two ends of the branch where the light emitting device and the driving transistor are located in the off-screen display mode is obviously reduced compared with the voltage difference between the two ends where the light emitting device and the driving transistor are located in the non-off-screen display mode, the power supply for generating driving current by the driving transistor is reduced, and the driving current is generated to drive the light emitting device. According to the technical scheme, the problem that standby time is shortened due to high power consumption of the screen-extinguishing display mode of the existing display device can be solved, display of basic information in the screen-extinguishing display mode is achieved, power consumption of the screen-extinguishing display mode is reduced, standby time of the display device is prolonged, and user experience is improved.

Drawings

Fig. 1 is a schematic structural diagram of a display device according to an embodiment of the present invention;

fig. 2 is a schematic circuit diagram of a pixel circuit according to an embodiment of the present invention;

fig. 3 is a schematic circuit diagram of another pixel circuit according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a display device according to an embodiment of the present invention;

fig. 5 is a schematic block diagram of a driving chip according to an embodiment of the present invention;

fig. 6 is a circuit schematic of a driving chip according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.

As described in the background art, after the conventional display device enters the standby mode, the user needs to wake up the mobile phone again if he needs to view basic information such as time information, weather information, short messages, and missed call information. In order to still view information in the standby mode, a screen-off mode (Always on display, AOD) is introduced, only partial areas of the screen are displayed in the AOD mode, the driving chip is in an idle state, basic information can be viewed without waking up equipment, and compared with the mode that the information is viewed by waking up equipment, the power consumption can be saved. However, the inventor researches that the power consumption of the existing display device is still high even if the display device is operated in the AOD mode, and the power consumption of the AOD mode can be up to about 100mW through analysis and calculation, so that the standby time of the display device is shortened, and the user experience is affected.

Based on the above problems, the embodiment of the invention provides a display panel. Fig. 1 is a schematic structural diagram of a display device according to an embodiment of the present invention, and fig. 1 schematically illustrates an arrangement of a display panel 20 in a display device 10. Fig. 2 is a schematic diagram of a pixel circuit according to an embodiment of the present invention, which may correspond to a specific circuit structure of the pixel circuit 100 shown in fig. 1. Referring to fig. 1 and 2, the display panel 20 includes a plurality of light emitting units, each of which includes a light emitting device D1 and its corresponding pixel circuit 100, and the display panel 20 further includes: a first power line ELVDD, a second power line ELVSS, and an initialization signal line Vint; each pixel circuit 100 is connected to the first power line ELVDD, the second power line ELVSS, and the initialization signal line Vint, respectively; in each of the light emitting units, the pixel circuit 100 includes a driving transistor DT and a light emitting device D1 sequentially connected between a first power line ELVDD and a second power line ELVSS, an initialization signal line Vint for transmitting an initialization signal to a gate electrode of the driving transistor DT or a first electrode of the light emitting device D1; in the off-screen display mode, the voltage transmitted from the first power line ELVDD to the first electrode of the driving transistor DT of the pixel circuit 100 is equal to the absolute value of the voltage on the initialization signal line Vint, and the voltage transmitted from the second power line ELVSS to the second electrode of the light emitting device D1 corresponding to the pixel circuit 100 is greater than the voltage thereof in the off-screen display mode.

Referring to fig. 1, the pixel circuit 100 may include a plurality of thin film transistors and storage capacitors, the thin film transistors may include a driving transistor and a switching transistor, and the driving transistor, the switching transistor, and the storage capacitor may form the pixel circuit 100 in various connection relations, for example, a 3T1C pixel circuit, a 7T1C pixel circuit, an 8T2C pixel circuit, and the like, where T represents a transistor, and C represents a capacitor. The driving transistor may generate a driving current to drive the light emitting device connected to the pixel circuit 100 to emit light, and the switching transistor mainly plays a role of switching. The first power line ELVDD may be used to transmit a first power signal and the second power line ELVSS may be used to transmit a second power signal. In the light emitting stage, a first power signal on the first power line ELVDD is applied to a first pole of the driving transistor, a second power signal on the second power line ELVSS is applied to a second pole of the light emitting device, for example, the second pole is a cathode, and the first power signal and the second power signal serve as power sources for generating driving currents for the driving transistor, so that the driving transistor generates the driving currents to drive the light emitting device to emit light. The first power line ELVDD may be a signal line directly connected to one pole (e.g., drain or source) of the driving transistor in the pixel circuit 100, or a signal line indirectly connected to one pole of the driving transistor in the pixel circuit 100 through a switching transistor (e.g., light emission control transistor), and the second power line ELVSS may be a signal line connected to the cathode of the light emitting device D1. The initialization signal line Vint may be used to transmit an initialization signal to the pixel circuit 100, for example, the initialization signal line Vint may be connected to a gate electrode and a storage capacitor of the driving transistor DT through a switching transistor, the initialization signal line Vint and the switching transistor connected thereto write the initialization signal into the gate electrode and the storage capacitor of the driving transistor, and initialize the gate electrode and the storage capacitor of the driving transistor to remove residual charges of a display screen of a previous frame, so as to avoid affecting a display screen of a next frame. The initialization signal line Vint may be connected to the anode of the light emitting device D1 through a switching transistor, and an initialization signal is written into the anode of the light emitting device D1 through the initialization signal line Vint and the switching transistor connected thereto, so as to initialize the potential of the anode of the light emitting device, so as to remove the residual charge of the display screen of the previous frame and avoid affecting the display screen of the next frame.

Fig. 2 schematically shows a case where the pixel circuit 100 is a 3T1C pixel circuit including a driving transistor DT, a first transistor M1, a second transistor M2, a storage capacitor C1, and a light emitting device D1, in combination with fig. 1 and 2. The Scan signal input from the second Scan signal line Scan2 may control the first transistor M1 to be turned on, so that the initialization signal input from the initialization signal line Vint is written into the storage capacitor C1 and the gate of the driving transistor DT. The Scan signal input from the first Scan signal line Scan1 may control the second transistor M2 to be turned on to write the data voltage signal input from the first data voltage signal line Vdata1 into the storage capacitor C1 and the gate of the driving transistor DT. The driving transistor DT may be turned on during the light emitting period, and a first power signal on the first power line ELVDD may be transmitted to a first pole of the driving transistor DT, while a second power signal on the second power line ELVSS may be transmitted to a cathode of the light emitting device D1, and the first power signal and the second power signal may be used as power sources for generating driving currents for the driving transistor DT, so that the driving transistor DT generates driving currents to drive the light emitting device D1 to emit light. The initialization signal line Vint in this embodiment may be a signal line connected to the second electrode of the first transistor M1, and in the off-screen display mode, the voltage transmitted to the first electrode of the driving transistor DT by the driving chip 200 is controlled to be equal to the absolute value of the voltage on the initialization signal line Vint, and the voltage transmitted to the cathode of the light emitting device D1 by the second power line ELVSS is controlled to be greater than the voltage in the off-screen display mode. Compared with a non-screen-off display mode, the voltage difference between the light emitting device D1 and the two ends of the branch where the driving transistor DT is located in the screen-off display mode is reduced, namely, the power supply for generating driving current of the driving transistor DT is reduced, and the power consumption of the screen-off display mode is saved.

Fig. 3 is a schematic diagram of another pixel circuit according to an embodiment of the present invention, which may correspond to another specific circuit structure of the pixel circuit 100 in the display panel shown in fig. 1, such as a 7T1C pixel circuit. Referring to fig. 1 and 3, the pixel circuit includes a driving transistor DT, a third transistor M3, a fourth transistor M4, a fifth transistor M5, a sixth transistor M6, a seventh transistor M7, an eighth transistor M8, a storage capacitor C1, and a light emitting device D1. The Scan signal input from the second Scan signal line Scan2 may control the fifth transistor M5 to be turned on to write the initialization signal input from the initialization signal line Vint to the anode of the light emitting device D1. The Scan signal input from the third Scan signal line Scan3 may control the sixth transistor M6 to be turned on to write the initialization signal input from the initialization signal line Vint into the storage capacitor C1 and the gate of the driving transistor DT. The Scan signal input from the first Scan signal line Scan1 may control the third transistor M3 to be turned on to write the data voltage signal input from the first data voltage signal line Vdata1 into the storage capacitor C1 and the gate of the driving transistor DT. In the light emitting stage, the driving transistor DT is turned on, the light emission control signal inputted from the first light emission control signal line EM1 may control the fourth transistor M4 and the eighth transistor M8 to be turned on, the first power signal on the first power line ELVDD is transmitted to the first electrode of the driving transistor DT through the fourth transistor M4, and the second power signal on the second power line ELVSS is transmitted to the cathode of the light emitting device D1, and the first power signal and the second power signal serve as power sources for generating driving currents for the driving transistor DT, so that the driving transistor DT generates driving currents to drive the light emitting device D1 to emit light. The initialization signal line Vint in this embodiment may also be a signal line connected to the first electrode of the fifth transistor M5 or the first electrode of the sixth transistor M6, and in the off-screen display mode, the voltage transmitted to the first electrode of the driving transistor DT by the first power line ELVDD may be controlled by the driving chip to be equal to the absolute value of the voltage on the initialization signal line Vint, and the voltage transmitted to the cathode of the light emitting device D1 by the second power line ELVSS may be controlled to be greater than the voltage thereof in the off-screen display mode. Compared with a non-screen-off display mode, the voltage difference between the light emitting device D1 and the two ends of the branch where the driving transistor DT is located in the screen-off display mode is reduced, namely, the power supply for generating driving current of the driving transistor DT is reduced, and the power consumption of the screen-off display mode is saved.

With reference to fig. 1 and 2, further description will be given of the beneficial effects of the technical solution of the present embodiment, in the non-screen display mode, that is, the normal display mode, the driving chip 200 in the display device may transmit an initialization signal to the pixel circuit through the initialization signal line Vint, transmit a first power signal to a first pole of the driving transistor DT in the pixel circuit through the first power line ELVDD, and transmit a second power signal to a second pole of the light emitting device D1 in the pixel circuit through the second power line ELVSS, so that the driving transistor DT generates a driving current to drive the light emitting device D1 to emit light, thereby controlling the display panel to perform normal display. Illustratively, the voltage on the first power line ELVDD is aV (e.g., a is about 10), the voltage on the second power line ELVSS is bV (e.g., b is about-10), and the voltage on the initialization signal line Vint is cV (e.g., c is about-3.5-2). In the non-off-screen display mode, the voltage difference across the branch where the light emitting device D1 and the driving transistor DT are located is substantially (a-b) V, about 20V. In the screen-off display mode, the picture displayed by the display device is usually a small icon or character in a black background, the light-emitting brightness of the light-emitting device D1 is lower than that of the screen-off display mode, the power supply for generating driving current by the driving transistor DT can be reduced, namely, the pressure difference between the driving transistor DT and the two ends of the branch where the light-emitting device D1 is positioned is reduced, so that the driving current generated by the driving transistor DT is smaller, and the light-emitting device D1 performs low-power consumption display. Therefore, the voltage transmitted to the first electrode of the driving transistor DT by the first power line ELVDD may be set to be equal to the absolute value |c| of the voltage on the initialization signal line Vint by the driving chip 200, and the voltage transmitted to the cathode of the light emitting device D1 by the second power line ELVSS may be controlled to be greater than the voltage thereof in the non-off-screen display mode, for example, the voltage may be 0, and at this time, the voltage difference between the light emitting device D1 and the branch circuit of the driving transistor DT is |c|, which is about 2V to 3.5V. In this way, the light emitting device D1 can emit light, and the voltage difference between the two ends of the branch where the light emitting device D1 and the driving transistor DT are located is reduced much compared with the voltage difference in the non-screen-off display mode, accordingly, the driving current of the light emitting device D1 is reduced much, so that the basic information can be displayed in the screen-off display mode, the power consumption of the screen-off display mode is saved, meanwhile, the power consumption of the circuit for generating the power supply signal by the driving chip is reduced, the standby time of the display device is prolonged, and the user experience is improved.

Referring to fig. 1 and 2, in the off-screen display mode, the voltage transmitted from the second power line ELVSS to the cathode of the corresponding light emitting device D1 of the pixel circuit 100 may be set to be equal to the voltage on the initialization signal line Vint. For example, the voltage on the second power line ELVSS may be set using a circuit structure for generating an initialization signal line in the driving chip 200 of the display device 10, wherein the voltage on the initialization signal line Vint is cV (e.g., c is about-3.5 to-2), that is, the voltage of the cathode of the light emitting device D1 is cV. Meanwhile, the voltage on the first power line ELVDD may also be set using a circuit structure in the driving chip for generating the initialization signal line such that the voltage transmitted to the first electrode of the driving transistor DT via the first power line ELVDD is an absolute value |c| of the voltage on the initialization signal line Vint. In the off-screen display mode, the driving transistor DT is controlled to be turned on, the voltage on the first power line ELVDD is |c|v, the voltage on the second power line ELVSS is cV, a voltage difference is formed between the light emitting device D1 and the branch where the driving transistor DT is located, the voltage difference is 2|c|v (about 4V to 7V), the driving transistor DT generates a driving current with a lower power source, and the light emitting device D1 emits light with low power consumption. The voltage transmitted to the cathode of the light emitting device D1 by the second power line ELVSS is equal to the voltage on the initialization signal line Vint, so that the voltage difference between two ends of the light emitting device in the screen-off display mode is smaller, the requirement of displaying basic information in the screen-off display mode can be met, and the overall power consumption of the display panel is reduced.

With continued reference to fig. 1 and 2, in the off-screen display mode, the voltage on the cathode of the light emitting device D1 corresponding to the second power line ELVSS transfer pixel circuit may also be set equal to the ground voltage. Illustratively, the voltage on the second power line ELVSS is set with a circuit structure grounded in the driving chip of the display device such that the voltage on the second power line ELVSS, i.e., the voltage of the second pole of the light emitting device D1, is a ground voltage, for example, the ground voltage is 0. Meanwhile, in the off-screen display mode, the driving transistor DT may be controlled to be turned on, and the voltage transmitted from the first power line ELVDD to the first electrode of the driving transistor DT may be set to be an absolute value |c|v of the voltage on the initialization signal line Vint, which is about 2V to 3.5V. The light emitting device D1 and the driving transistor are formed with a voltage difference |c| on the branch where the driving transistor DT generates a driving current with a low power source, and the light emitting device D1 emits light with low power consumption. Compared with the solution in the above embodiment, the technical solution of the present embodiment can halve the voltage difference between the driving transistor and the branch where the light emitting device is located in the screen display mode, thereby saving the power consumption of the display panel.

The embodiment of the invention also provides a display device, fig. 4 is a schematic structural diagram of the display device provided by the embodiment of the invention, the display device can be a mobile phone, a computer or an intelligent wearable device with a display function, and fig. 4 shows the situation that the display device is a mobile phone. Referring to fig. 1, 2 and 4, the display device 10 includes a display panel 20 and a driving chip 200; the display panel 20 includes a plurality of light emitting units, each of which includes a light emitting device D1 and its corresponding pixel circuit 100, and the display panel 20 further includes a first power line ELVDD, a second power line ELVSS, and an initialization signal line Vint; each pixel circuit 100 is connected to a first power line ELVDD, a second power line ELVSS, and an initialization signal line Vint for transmitting an initialization signal to a gate electrode of the driving transistor DT or a first electrode of the light emitting device D1, respectively, the pixel circuit 100 including the driving transistor DT, the driving transistor DT and the light emitting device D1 being sequentially connected between the first power line ELVDD and the second power line ELVSS; the driving chip 200 includes a first power supply output terminal (ELVDD), a second power supply output terminal (ELVSS), and an initialization signal output terminal (Vint), which are connected to the first power supply line ELVDD, the second power supply line ELVSS, and the initialization signal line Vint, respectively; the first power line ELVDD transmits the voltage output from the first power output terminal (ELVDD) to the first pole of the driving transistor DT in the pixel circuit 100, the second power line ELVSS transmits the voltage output from the second power output terminal (ELVSS) to the cathode of the corresponding light emitting device D1 of the pixel circuit 100, and the initialization signal output terminal (Vint) outputs an initialization signal to the initialization signal line Vint; the driving chip 200 is used for outputting a voltage equal to an absolute value of a voltage output by the initialization signal output terminal (Vint) through the first power output terminal (ELVDD) in the off-screen display mode, and outputting a voltage greater than a voltage output by the second power output terminal (ELVSS) in the non-off-screen display mode.

Specifically, referring to fig. 1, the driving chip 200 may be a power driving chip for supplying power signals, such as a first power signal, a second power signal, and an initialization signal, for driving the pixel circuit 100 to operate. In the display device 10, the Scan signals on the first Scan signal line Scan1 to the n-th Scan signal line Scan n may be supplied from a gate driving chip (not shown) in the display device 10; the data voltage signals on the first to nth data voltage signal lines Vdata1 to Vdata n may be supplied from a data driving chip (not shown) or the driving chip 200 in the display device 10; the light emission control signals on the first through nth light emission control signal lines EM1 through EM n may be supplied from a light emission control driving chip (not shown) in the display device 10. In the non-off-screen display mode, i.e., the normal display mode, the driving chip 200 may transmit an initialization signal output from the initialization signal output terminal (Vint) thereof to the pixel circuit through the initialization signal line Vint, output a first power signal through the first power output terminal (ELVDD), so that the first power signal is transmitted to the first pole of the driving transistor DT in the pixel circuit through the first power line ELVDD, output a second power signal through the second power output terminal (ELVSS), so that the second power signal is transmitted to the cathode of the light emitting device D1 in the pixel circuit through the second power line ELVSS, and the first power signal and the second power signal serve as power sources for generating driving currents for the driving transistor DT to generate the driving currents to drive the light emitting device D1 to emit light, thereby controlling the display panel to perform normal display.

Illustratively, referring to fig. 1 and 2, the driving chip 200 outputs a voltage of aV (e.g., a about 10) through the first power output terminal (ELVDD), a voltage of bV (e.g., b about-10) through the second power output terminal (ELVSS), and a voltage of cV (e.g., c about-3.5 to-2) through the initialization signal output terminal (Vint). In the non-off-screen display mode, the voltage difference across the branch where the light emitting device D1 and the driving transistor DT are located is substantially (a-b) V, about 20V. In the screen-off display mode, the picture displayed by the display device is usually a small icon or character in a black background, the light-emitting brightness of the light-emitting device D1 is lower than that of the screen-off display mode, the power supply for generating driving current by the driving transistor DT can be reduced, namely, the pressure difference between the driving transistor DT and the two ends of the branch where the light-emitting device D1 is positioned is reduced, so that the driving current generated by the driving transistor DT is smaller, and the light-emitting device D1 performs low-power consumption display. Therefore, the voltage outputted through the first power output terminal (ELVDD) may be set to be equal to the absolute value |c| of the voltage outputted through the initialization signal output terminal (Vint) by the driving chip 200, and the voltage outputted through the second power output terminal (ELVSS) may be greater than the voltage outputted in the non-off-screen display mode, for example, the voltage may be 0, and at this time, the voltage difference between the light emitting device D1 and the branch circuit where the driving transistor DT is located is about 2V to 3.5V. In this way, the light emitting device D1 can emit light, and the voltage difference between the two ends of the branch where the light emitting device D1 and the driving transistor DT are located is reduced much compared with the voltage difference in the non-screen-off display mode, accordingly, the driving current of the light emitting device D1 is reduced much, so that the basic information can be displayed in the screen-off display mode, the power consumption of the screen-off display mode is saved, meanwhile, the power consumption of the circuit for generating the power supply signal by the driving chip is reduced, the standby time of the display device is prolonged, and the user experience is improved.

Fig. 5 is a schematic block diagram of a driving chip according to an embodiment of the present invention, and fig. 5 may correspond to a specific block structure of the driving chip 200 in fig. 1. Referring to fig. 2 and 5, the driving chip 200 may be provided to include an inverter 210 and a first switch 220, and the initialization signal output terminal (Vint) is connected to the first power output terminal (ELVDD) through the inverter 210 and the first switch 220. Specifically, in the off-screen display mode, the first switch 220 may be controlled to be turned on by the driving chip 200, so that the initialization signal of the initialization signal output terminal (Vint) may be transmitted to the first power output terminal (ELVDD) through the turned-on first switch 220 after being subjected to the inversion process by the inverter 210, so as to ensure that the voltage output by the first power output terminal (ELVDD) is equal to the absolute value of the voltage output by the initialization signal output terminal (Vint). The voltage value of the initializing signal output terminal (Vint) is negative, the initializing signal output by the initializing signal output terminal (Vint) is inverted by the inverter 210, and the voltage value corresponding to the signal transmitted to the first power output terminal (ELVDD) through the first switch 220 is positive, so that the signal can be transmitted to the first pole of the driving transistor DT through the first power line ELVDD to be used as the power source for generating the driving current for the driving transistor DT. In the non-screen-off display mode, if the pixel circuit 100 is controlled by the driving chip 200 to drive the light emitting device to perform normal light emitting display, the first switch 220 may be controlled to be turned off to disconnect the first power output terminal (ELVDD) and the initialization signal output terminal (Vint), and a normal first power signal is output to the pixel circuit 100 through the first power output terminal (ELVDD). In the non-screen-off display mode, the voltage output by the driving chip 200 through the first power output terminal (ELVDD) is aV (e.g., a is about 10), and in the screen-off display mode, the voltage output by the driving chip 200 through the first power output terminal (ELVDD) is the absolute value |c|v (e.g., c is about-3.5 to-2) of the voltage output by the initialization signal output terminal (Vint), so that the voltage on the first power line ELVDD is smaller than the voltage thereof in the non-screen-off display mode, which not only ensures the display of basic information in the screen-off display mode, but also helps to reduce the voltage difference across the light emitting device, thereby reducing the power consumption of the display device and being beneficial to prolonging the standby time of the display device.

Referring to fig. 2 and 5, the driving chip 200 may further include a second switch 230, and the initialization signal output terminal (Vint) is connected to the second power output terminal (ELVSS) through the second switch 230. Specifically, in the off-screen display mode, the second switch 230 may be controlled to be turned on by the driving chip 200, so that the initialization signal of the initialization signal output terminal (Vint) may be transmitted to the second power output terminal (ELVSS) through the second switch 230, and at this time, the voltage output by the second power output terminal (ELVSS) is equal to the voltage c output by the initialization signal output terminal (Vint). Since the voltage value c of the initialization signal is a negative value, the voltage value of the signal transmitted to the cathode of the light emitting device D1 through the second power line ELVSS is also a negative value, while the voltage value of the signal transmitted to the anode of the light emitting device D1 through the first power line ELVDD and the first power output (ELVDD) is a positive value, a voltage difference is formed between the light emitting device D1 and the two ends of the branch where the driving transistor DT is located, and a current flows in the light emitting device D1 to emit light. In the non-screen-off display mode, if the pixel circuit 100 is controlled by the driving chip 200 to drive the light emitting device to perform normal light emitting display, the second switch 230 may be controlled to be turned off to disconnect the second power output terminal (ELVSS) from the initialization signal output terminal (Vint), and a normal second power signal is output to the pixel circuit 100 through the second power output terminal (ELVSS). Thus, in the non-screen-off display mode, the voltage output by the driving chip 200 through the second power output terminal (ELVSS) is bV (b is about-10), in the screen-off display mode, the voltage output by the driving chip 200 through the second power output terminal (ELVSS) is the voltage value cV (c is about-3.5 to-2) output by the initialization signal output terminal (Vint), so that the voltage value output by the second power output terminal (ELVSS) in the screen-off display mode is greater than the voltage value output by the second power output terminal (ELVSS) in the non-screen-off display mode, which is conducive to reducing the voltage difference across the light emitting device D1, not only ensuring the display of basic information in the screen-off display mode, but also reducing the power consumption of the display device and being conducive to prolonging the standby time of the display device.

With continued reference to fig. 2 and 5, the driving chip 200 may further include a third switch 240, and the initialization signal output terminal (Vint) may also be grounded through the third switch 240. In the off-screen display mode, the third switch 240 may be controlled to be turned on by the driving chip 200 so that the second power output terminal (ELVSS) outputs the ground signal, and at this time, the voltage output from the second power output terminal (ELVSS) may be 0. In the non-screen-off display mode, if the pixel circuit 100 is controlled by the driving chip 200 to drive the light emitting device to perform normal light emitting display, the third switch 240 may be controlled to be turned off to disconnect the second power output terminal (ELVSS) from the ground signal, and the normal second power signal is output to the pixel circuit 100 through the second power output terminal (ELVSS). Thus, in the non-off-screen display mode, the voltage output by the driving chip 200 through the second power output terminal (ELVSS) is bV (b is about-10), and in the off-screen display mode, the voltage output by the driving chip 200 through the second power output terminal (ELVSS) is 0, so that the voltage value output by the second power output terminal (ELVSS) in the off-screen display mode is greater than the voltage value output by the second power output terminal (ELVSS) in the non-off-screen display mode. Compared with the scheme of the embodiment, the scheme of the embodiment has the advantages that the voltage difference between two ends of the light emitting device is smaller, and the power consumption of the display device can be further increased, so that the standby time of the display device can be prolonged.

With continued reference to fig. 2 and 5, the driving chip 200 may further be provided to include a power signal generating circuit 250 connected to the first power output terminal (ELVDD) and the second power output terminal (ELVSS), the power signal generating circuit 250 for generating the first power signal and outputting through the first power output terminal (ELVDD) and generating the second power signal and outputting through the second power output terminal (ELVSS) in the non-off-screen display mode; the driving chip 200 is further used for controlling the power signal generating circuit 250 to stop working in the off-screen display mode. Specifically, the power signal generating circuit 250 may be configured to generate a first power signal and a second power signal, and in the non-off-screen display mode, the power signal generating circuit 250 may be controlled to operate by the driving chip 200, such that the power signal generating circuit 250 outputs the first power signal to the pixel circuit 200 through the first power output terminal (ELVDD) and outputs the second power signal to the pixel circuit 200 through the second power output terminal (ELVSS), so as to drive the light emitting device to normally emit light through the driving transistor DT.

In the prior art, in the off-screen display mode, the first power signal and the second power signal are still generally supplied to the pixel circuit 200 through the power signal generating circuit 250, so that the voltage difference across the light emitting device is large, and the power consumption is also large. In the technical solution of the embodiment of the present invention, in order to save power consumption in the off-screen display mode, the driving chip 200 may control the power signal generating circuit 250 to stop working and control the first switch 220 to be turned on, so that after the initialization signal of the initialization signal output terminal (Vint) is capable of performing the inversion processing through the inverter 210, the initialization signal is transmitted to the first power output terminal (ELVDD) through the turned-on first switch 220, and the first power signal is provided to the pixel circuit 200 through the initialization signal with relatively low voltage, the inverter 210 and the first switch 220. Meanwhile, any one of the second switch 230 and the third switch 240 is controlled to be turned on by the driving chip 200 to supply the second power signal to the pixel circuit 200 through the initialization signal or the ground signal, without applying the power signal generating circuit 250 to supply power to the light emitting device, thereby saving power consumption of the driving chip 200.

Fig. 6 is a schematic circuit diagram of a driving chip according to an embodiment of the present invention, and fig. 6 may correspond to a specific circuit structure of the driving chip shown in fig. 5. As shown in fig. 6, the driving chip 200 may include an initialization signal generating circuit 260 connected to an initialization signal output terminal (Vint) for generating an initialization signal; the inverter 210 includes a first transistor T1 and a second transistor T2, control terminals of the first transistor T1 and the second transistor T2 are connected to each other, a first terminal of the first transistor T1 and a first terminal of the second transistor T2 are connected to the initialization signal generating circuit 260, a second terminal of the first transistor T1 is connected to a second terminal of the second transistor T2 and a first terminal of the first switch 220, and a second terminal of the first switch 220 is connected to a first power supply output terminal (ELVDD); the driving chip 200 is further used for controlling the first transistor T1, the second transistor T2 and the first switch 220 in the off-screen display mode, and outputting the initialization signal generated by the initialization signal generating circuit 260 to the first power output terminal (ELVDD).

Referring to fig. 2 and 6, the initialization signal generation circuit 260 in the driving chip 200 may generate an initialization signal that can be used to initialize the driving transistor DT or the storage capacitor C1 in the pixel circuit 100, the voltage value of which is generally a negative value. The initialization signal generating circuit 260 may include at least two initialization signal output terminals, the first initialization signal output terminal a1 may output an initialization signal having a negative voltage value, the second initialization signal output terminal a2 may output an initialization signal having a positive voltage value, and absolute values of the voltage values of the initialization signals output by the first and second initialization signal output terminals a1 and a2 are equal. The transistors in this embodiment and the following embodiments may be oxide transistors, low-temperature polysilicon thin film transistors, or the like. For convenience of control, it may be preferable to set the channel types of the first transistor T1 and the second transistor T2 to be different, and set the first switch 220 as the diode D2. The process of the driving chip 200 outputting the first power signal through the first power output terminal (ELVDD) is exemplarily described as follows with reference to fig. 2 and 6:

In the non-off screen display mode, the power signal generating circuit 250 may be controlled to operate by the driving chip 200, a low level signal may be output to the first signal line S1 and a low level signal may be output to the third signal line S3 by the driving chip 200, the driving transistor DT and the first transistor T1 may be turned on, and the second transistor T2 may be turned off. The initialization signal generating circuit 260 outputs an initialization signal having a voltage value of negative value c through the first initialization signal output terminal a1, which may be output to the diode D2 through the first transistor T1 such that the diode D2 is turned off. The power signal generating circuit 250 outputs a first power signal and transmits the first power signal to the first pole of the driving transistor DT through the first power output terminal (ELVDD) and the first power line ELVDD, and transmits a second power signal to the cathode of the light emitting device D1 through the driving chip 200, driving the light emitting device D1 to normally emit light.

In the off-screen display mode, the power signal generation circuit 250 may be controlled to stop operation by the driving chip 200 in order to save power consumption. The driving chip 200 outputs a high level signal to the first signal line S1 and outputs a low level signal to the third signal line S3, and the driving transistor DT and the second transistor T2 are turned on and the first transistor T1 is turned off. The initialization signal generating circuit 260 outputs an initialization signal with a positive voltage value through the second initialization signal output terminal a2, and the initialization signal can be output to the diode D2 through the second transistor T2, so that the diode D2 can be turned on in a forward direction, and the initialization signal with the positive voltage value |c| is transmitted to the first pole of the driving transistor DT through the diode D2, the first power output terminal (ELVDD) and the first power line ELVDD, and the voltage value |c| (for example, about 2V to about 3.5V) of the first pole of the driving transistor DT in the off-screen display mode is much smaller than the voltage value aV (for example, about a 10) of the first pole of the driving transistor DT in the non-off-screen display mode, which is helpful for reducing the voltage difference across the light emitting device D1 to achieve the purpose of reducing the power consumption.

With continued reference to fig. 6, the second switch 230 may include a third transistor T3, a first terminal of the third transistor T3 being connected to the initialization signal generation circuit 260, a second terminal of the third transistor T3 being connected to the second power supply output terminal (ELVSS); the driving chip 200 may also be used to control the third transistor T3 in the off-screen display mode, and output the initialization signal generated by the initialization signal generating circuit 260 to the second power output terminal (ELVSS) through the third transistor T3. The third switch 240 may include a fourth transistor T4, a first terminal of the fourth transistor T4 being grounded, a second terminal of the fourth transistor T4 being connected to a second power supply output terminal (ELVSS); the driving chip 200 may also be used to control the fourth transistor T4 in the off-screen display mode, and output a ground signal to the second power output terminal (ELVSS) through the fourth transistor T4. A process in which the driving chip 200 outputs the second power signal through the second power output terminal (ELVSS) will be exemplarily described with reference to fig. 2 and 6 as follows:

in the non-off screen display mode, the power supply signal generating circuit 250 may be controlled to operate by the driving chip 200, and a low level signal may be output to the third signal line S3 by the driving chip 200, so that the driving transistor DT is turned on, and at this stage the driving chip 200 does not provide any signal to the second signal line S2, and both the third transistor T3 and the fourth transistor T4 are turned off. The power signal generating circuit 250 outputs a first power signal to a first pole of the driving transistor DT through a first power output terminal (ELVDD) and a first power line ELVDD, and outputs a second power signal to a cathode of the light emitting device D1 through a second power output terminal (ELVSS) and a second power line ELVSS, and the driving transistor DT generates a driving current according to the first power signal and the second power signal to drive the light emitting device D1 to normally emit light.

In the off-screen display mode, the power signal generation circuit 250 may be controlled to stop operation by the driving chip 200 in order to save power consumption. The driving chip in the mode can have two working modes:

in the first operation mode, the driving chip 200 outputs a high level signal to the second signal line S2 and outputs a low level signal to the third signal line S3, the driving transistor DT and the third transistor T3 are turned on, and the fourth transistor T4 is turned off. The initialization signal generation circuit 260 outputs an initialization signal having a voltage value of negative value c through the first initialization signal output terminal a1, which may output a second power signal to the cathode of the light emitting device D1 through the third transistor T3, the second power output terminal (ELVSS), and the second power line ELVSS. In the first working mode of the screen-off display mode, the voltage value c of the cathode of the light-emitting device D1 is larger than that of the cathode of the light-emitting device D1 in the non-screen-off display mode, so that the pressure difference between two ends of the light-emitting device D1 is reduced, and meanwhile, the light-emitting device D1 is ensured to perform light-emitting display in the screen-off display mode, and the purpose of reducing power consumption is achieved.

In the second operation mode, the driving chip 200 outputs a low level signal to the second signal line S2 and outputs a low level signal to the third signal line S3, the driving transistor DT and the fourth transistor T4 are turned on, and the third transistor T3 is turned off. The initialization signal generation circuit 260 may not operate at this stage, and can reduce a part of power consumption for the driving chip. The fourth transistor T4 is grounded, and the ground signal may output a second power signal to the cathode of the light emitting device D1 through the fourth transistor T4, the second power output terminal (ELVSS), and the second power line ELVSS. In the second working mode of the screen-off display mode, the voltage value 0 of the cathode of the light-emitting device D1 is larger than that of the cathode of the light-emitting device D1 in the non-screen-off display mode, so that the pressure difference between two ends of the light-emitting device D1 is reduced, and the pressure difference between two ends of the light-emitting device D1 in the second working mode is smaller than that between two ends of the light-emitting device D1 in the first working mode, so that the power consumption can be further reduced. The driving chip 200 may be set to operate in the first operation mode or the second operation mode in the screen-off display mode according to actual requirements.

It should be noted that, fig. 5 and fig. 6 both show that the second switch 230 and the third switch 240 are simultaneously disposed on the driving chip 200, so that the driving chip 200 has two working modes in the screen-off display mode, and any one of the second switch 230 and the third switch 240 may be selected to be disposed on the driving chip 200, so that the purpose of saving power consumption of the display device can be achieved.

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims (12)

1. A display panel comprising a plurality of light emitting cells, each of the light emitting cells comprising a light emitting device and its corresponding pixel circuit, the display panel further comprising:

A first power line, a second power line, and an initialization signal line;

each of the pixel circuits is connected to the first power supply line, the second power supply line, and the initialization signal line, respectively; in each of the light emitting units, the pixel circuit includes a driving transistor, the driving transistor and the light emitting device being sequentially connected between the first power line and the second power line;

in the off-screen display mode, the voltage of the initialization signal line is transmitted to a first power line through a circuit connected with an inverter to obtain the voltage transmitted to a first pole of the driving transistor in the pixel circuit by the first power line, wherein the voltage transmitted to the first pole of the driving transistor in the pixel circuit by the first power line is equal to the absolute value of the voltage on the initialization signal line, and the voltage transmitted to a second pole of the light emitting device corresponding to the pixel circuit by the second power line is larger than the voltage of the light emitting device in the non-off-screen display mode.

2. The display panel according to claim 1, wherein in the off-screen display mode, a voltage transmitted from the second power line to the second electrode of the light emitting device corresponding to the pixel circuit is equal to a voltage on the initialization signal line.

3. The display panel according to claim 1, wherein in the off-screen display mode, a voltage transmitted from the second power line to the second electrode of the light emitting device corresponding to the pixel circuit is equal to a ground voltage.

4. A display device is characterized by comprising a display panel and a driving chip;

the display panel includes a plurality of light emitting units, each of the light emitting units including a light emitting device and a corresponding pixel circuit thereof, the display panel further including: a first power line, a second power line, and an initialization signal line;

each of the pixel circuits is connected to the first power supply line, the second power supply line, and the initialization signal line, respectively; in each of the light emitting units, the pixel circuit includes a driving transistor, the driving transistor and the light emitting device being sequentially connected between the first power line and the second power line;

the driving chip comprises a first power supply output end, a second power supply output end and an initialization signal output end which are respectively connected with the first power supply line, the second power supply line and the initialization signal line; the first power line transmits the voltage output by the first power output end to a first pole of the driving transistor in the pixel circuit, and the second power line transmits the voltage output by the second power output end to a second pole of the light emitting device corresponding to the pixel circuit;

The driving chip is used for outputting voltage which is equal to the absolute value of the voltage which is output by the initialization signal output end through the first power output end in the screen-off display mode, and outputting voltage which is larger than the voltage which is output by the second power output end in the screen-off display mode;

the driving chip comprises an inverter and a first switch, and the initialization signal output end is connected with the first power supply output end through the inverter and the first switch.

5. The display device according to claim 4, wherein the driving chip further comprises a second switch, and the initialization signal output terminal is connected to the second power output terminal through the second switch.

6. The display device according to claim 4, wherein the driving chip further comprises a third switch, and the initialization signal output terminal is grounded through the third switch.

7. The display device according to claim 4, wherein the driving chip further comprises a power signal generating circuit connected to the first power output terminal and the second power output terminal, the power signal generating circuit being configured to generate a first power signal and output through the first power output terminal in a non-off-screen display mode, and generate a second power signal and output through the second power output terminal;

The driving chip is also used for controlling the power supply signal generating circuit to stop working in a screen-off display mode.

8. The display device according to claim 4, wherein the driving chip further comprises an initialization signal generating circuit connected to the initialization signal output terminal for generating an initialization signal;

the inverter comprises a first transistor and a second transistor, wherein the control ends of the first transistor and the second transistor are connected with each other, the first end of the first transistor and the first end of the second transistor are connected to the initialization signal generating circuit, the second end of the first transistor is connected with the second end of the second transistor and the first end of the first switch, and the second end of the first switch is connected with the first power supply output end;

the driving chip is also used for controlling the first transistor, the second transistor and the first switch in a screen-off display mode and outputting an initialization signal generated by the initialization signal generating circuit to the first power supply output end.

9. The display device according to claim 8, wherein channel types of the first transistor and the second transistor are different.

10. The display device of claim 8, wherein the first switch comprises a diode.

11. The display device according to claim 5, wherein the driving chip further comprises an initialization signal generating circuit connected to the initialization signal output terminal for generating an initialization signal;

the second switch comprises a third transistor, a first end of the third transistor is connected with the initialization signal generation circuit, and a second end of the third transistor is connected with the second power supply output end;

the driving chip is also used for controlling the third transistor in a screen-off display mode, and outputting the initialization signal generated by the initialization signal generating circuit to the second power supply output end through the third transistor.

12. The display device according to claim 6, wherein the third switch comprises a fourth transistor, a first terminal of the fourth transistor is grounded, and a second terminal of the fourth transistor is connected to the second power supply output terminal;

the driving chip is also used for controlling the fourth transistor in a screen-off display mode, and outputting a grounding signal to the second power supply output end through the fourth transistor.

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