CN114373427A - OLED driving circuit, display panel, preparation method and display device - Google Patents
OLED driving circuit, display panel, preparation method and display device Download PDFInfo
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- CN114373427A CN114373427A CN202210095449.5A CN202210095449A CN114373427A CN 114373427 A CN114373427 A CN 114373427A CN 202210095449 A CN202210095449 A CN 202210095449A CN 114373427 A CN114373427 A CN 114373427A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/006—Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3233—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
Abstract
The invention relates to an OLED driving circuit, a display panel, a preparation method and display equipment, wherein in the circuit, the anode of an organic light-emitting diode is connected with a driving node, and the cathode of the organic light-emitting diode is connected with a low power supply voltage end; the cathode of the diode device is connected with the anode of the organic light-emitting diode; the output end of the auxiliary cathode line is connected with the anode of the diode device, and the auxiliary cathode line receives a test current signal; a connecting part is arranged between the low power supply voltage end and the auxiliary cathode circuit; in the aging test period, the connecting part is disconnected, so that the auxiliary cathode line transmits a test current signal to the organic light emitting diode; and after the aging test time interval is ended, the connecting part is conducted so that the organic light emitting diode works normally. In the aging test process, the flowing large current can avoid a TFT passage, the negative effect of the large current on a TFT device is eliminated, the normal light emitting of the organic light emitting diode is not influenced after the aging test is finished, and the reliability of the OLED drive circuit is improved.
Description
Technical Field
The invention relates to the technical field of display, in particular to an OLED driving circuit, a display panel, a preparation method and display equipment.
Background
An OLED (Organic Light-Emitting Diode) is an active Light-Emitting device, and compared with an LCD (Liquid Crystal Display) Display mode, the OLED Display device does not need to provide a backlight source, has the advantages of being ultra-thin, high in brightness, low in driving voltage, and the like, and is considered as a next-generation Display device.
After the initial fabrication of the organic light emitting diode in the OLED display device is completed, a large current needs to be introduced for a long time (e.g., several hours) to perform an aging test, so as to enable the light emitting diode to rapidly pass through the previous brightness fluctuation and the rapid decay period, thereby improving the stability of the light emitting diode.
In the prior art, a driving TFT of an OLED is fully turned on, then a high voltage is applied between VDD and VSS, so that a large current flows through a light emitting diode for an aging test, but the large current can pass through a TFT device at the same time, and irreversible negative effects are easily caused on the function and stability of the TFT device.
Disclosure of Invention
Therefore, it is necessary to provide an OLED driving circuit, a display panel, a manufacturing method and a display device, aiming at the problem that a large current is likely to cause irreversible influence on the function and stability of a TFT device in the existing OLED aging test.
In a first aspect, the present application provides an OLED driving circuit, comprising:
the TFT drive circuit comprises a drive node and a low power supply voltage end;
the anode of the organic light-emitting diode is used for being connected with the driving node, and the cathode of the organic light-emitting diode is connected with the low power supply voltage end;
the cathode of the diode device is connected with the anode of the organic light-emitting diode;
an auxiliary cathode line, an output of the auxiliary cathode line being connected to an anode of the diode device, an input of the auxiliary cathode line being configured to receive the test current signal;
wherein, a connecting part is arranged between the low power supply voltage end and the auxiliary cathode circuit; in the aging test period, the connecting part is disconnected, so that the auxiliary cathode line transmits a test current signal to the organic light emitting diode; and after the aging test time period is ended, the connecting part is conducted.
Optionally, after the aging test period is finished, the connection portion is conducted based on laser.
Optionally, the TFT driving circuit further includes a high power supply voltage terminal, a first transistor, a second transistor, a third transistor, and a capacitor element;
a first terminal of the first transistor is connected to the high power supply voltage terminal, a second terminal of the first transistor is connected to the driving node, and a gate of the first transistor is connected to a second terminal of the second transistor; the first terminal of the second transistor is used for connecting a data line, and the grid electrode of the second transistor is used for accessing a first scanning signal; a first terminal of the third transistor is used for connecting the sensing line, a second terminal of the third transistor is used for connecting the driving node, and a grid electrode of the third transistor is used for accessing the second scanning signal; the first end of the capacitor element is connected with the grid of the first transistor, and the second end of the capacitor element is connected with the driving node.
Optionally, the first transistor, the second transistor, and the third transistor are N-type thin film transistors, respectively.
In a second aspect, the present application provides a display panel comprising:
a substrate;
the circuit layer is arranged on the substrate;
the packaging layer covers the circuit layer;
wherein the circuit layer is provided with any one of the OLED drive circuits.
Optionally, the circuit layer comprises an auxiliary cathode line layer and a cathode layer; the auxiliary cathode circuit layer is arranged close to the substrate, and the cathode layer is arranged close to the packaging layer; the auxiliary cathode line layer is provided with an auxiliary cathode line, and the cathode layer is provided with a low power supply voltage end.
Optionally, the substrate further comprises a buffer layer disposed between the substrate and the circuit layer.
In a third aspect, the present application provides a method for manufacturing a display panel, including:
providing a substrate;
preparing a circuit layer on a substrate;
preparing an encapsulation layer on the circuit layer;
wherein an OLED drive circuit as any one of the above is prepared in the circuit layer; keeping the connection part of the OLED driving circuit disconnected in the aging test period so that the auxiliary cathode line of the OLED driving circuit transmits a test current signal to the organic light emitting diode; and after the aging test time period is ended, the connecting part is conducted.
Optionally, after the aging test period is ended, the step of turning on the connection portion includes:
after the aging test time period is finished, the connecting part is welded based on laser welding so as to be conducted.
In a fourth aspect, the present application provides a display device comprising the display panel of any one of the above.
One of the above technical solutions has the following advantages and beneficial effects:
in the OLED driving circuit provided in each embodiment of the present application, the TFT driving circuit includes a driving node and a low power supply voltage terminal; the anode of the organic light emitting diode is used for connecting the driving node, and the cathode of the organic light emitting diode is connected with the low power supply voltage end; the cathode of the diode device is connected with the anode of the organic light-emitting diode; an output end of the auxiliary cathode line is connected with an anode of the diode device, and an input end of the auxiliary cathode line is configured to receive the test current signal; a connecting part is arranged between the low power supply voltage end and the auxiliary cathode circuit; in the aging test period, the connecting part is disconnected, so that the auxiliary cathode line transmits a test current signal to the organic light emitting diode; after the aging test period is finished, the connecting part is conducted so that the organic light emitting diode can normally work, further the aging test of the Organic Light Emitting Diode (OLED) is realized, in the aging test process, the flowing large current can avoid a TFT channel, the negative effect of the large current on a TFT device is eliminated, and the normal light emitting of the organic light emitting diode cannot be influenced after the aging test is finished. According to the OLED drive circuit, the diode device is additionally arranged between the anode of the organic light-emitting diode and the auxiliary cathode line, the auxiliary cathode line is used as a flowing path of a large current, and a TFT channel is avoided, so that the negative influence of the large current on the TFT is eliminated, the irreversible influence of the large current on the function and the stability of the TFT device in an OLED aging test is avoided, and the reliability of the OLED drive circuit is improved.
Drawings
The foregoing and other objects, features and advantages of the application will be apparent from the following more particular description of preferred embodiments of the application, as illustrated in the accompanying drawings. Like reference numerals refer to like parts throughout the drawings, and the drawings are not intended to be drawn to scale in actual dimensions, emphasis instead being placed upon illustrating the subject matter of the present application.
Fig. 1 is a circuit diagram of a conventional OLED driving circuit.
Fig. 2 is a circuit diagram of an OLED driving circuit in the embodiment of the present application.
Fig. 3 is a circuit diagram of an OLED driving circuit in an embodiment of the present application.
Fig. 4 is a schematic structural diagram of a display panel in an embodiment of the present application.
Fig. 5 is a schematic flow chart illustrating a manufacturing method of a display panel in an embodiment of the present application.
Description of reference numerals:
100. a TFT drive circuit; 102. a drive node; 104. a low supply voltage terminal; 106. a high supply voltage terminal; 108. a first transistor; 112. a second transistor; 114. a third transistor; 116. a capacitive element; 200. an organic light emitting diode; 300. a diode device; 400. an auxiliary cathode line; 500. a connecting portion. 600. A substrate; 700. a circuit layer; 800. and (7) packaging the layer.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are shown in the drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element and be integral therewith, or intervening elements may also be present. The terms "disposed," "one end," "the other end," and the like as used herein are for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The existing LED aging test circuit is to fully open the drive TFT of the LED and then increase the voltage between VDD and VSS, so that the heavy current flows through the OLED, and the heavy current can pass through the TFT device, thereby causing irreversible negative effects on the function and stability of the TFT device. As shown in fig. 1, is a conventional burn-in test circuit for a large size top emission AMOLED display panel. In the aging process of the light emitting diode, a higher voltage is loaded on the G node to enable the TFT device T1 to be fully turned on, and a large current flows through the TFT device T1 to reach the light emitting diode, so that the function and the stability of the light emitting diode are negatively affected due to the fact that the TFT device T1 is under a forward stress (stress) for a long time.
The problem that large current is prone to causing irreversible influence on functions and stability of a TFT device in the existing OLED aging test is solved, and negative influence of the large current on the TFT device is eliminated. In one embodiment, as shown in fig. 2 and 3, there is provided an OLED driving circuit including: a TFT driving circuit 100, an organic light emitting diode 200, a diode device 300, and an auxiliary cathode line 400.
The TFT driver circuit 100 includes a driving node 102 and a low power supply voltage terminal 104; the anode of the organic light emitting diode 200 is used for connecting the driving node 102, and the cathode of the organic light emitting diode 200 is connected with the low power voltage terminal 104; the cathode of the diode device 300 is connected to the anode of the organic light emitting diode 200; an output of the auxiliary cathode line 400 is connected to an anode of the diode device 300, and an input of the auxiliary cathode line 400 is configured to receive the test current signal; wherein, a connection part 500 is arranged between the low power voltage end 104 and the auxiliary cathode line 400; in the burn-in test period, the connection part 500 is opened to allow the auxiliary cathode line 400 to transmit a test current signal to the organic light emitting diode 200; after the burn-in test period is finished, the connection part 500 is turned on.
The TFT driving circuit 100 may be a current-controlled TFT driving circuit 100, for example, the TFT driving circuit 100 may be, but is not limited to, a 3T1C driving circuit or a 2T1C driving circuit. The 3T1C type driving circuit means that the driving circuit includes 3 TFT devices and 1 capacitive element 116. The 2T1C type driving circuit means that the driving circuit includes 2 TFT devices and 1 capacitive element 116. The TFT driving circuit 100 will be described below by taking a 3T1C type driving circuit as an example.
The TFT driver circuit 100 includes a driving node 102 and a low power supply voltage terminal 104. The driving node 102 refers to a connection node transmitting a driving signal to the organic light emitting diode 200. For example, the output terminal of the driving TFT device in the TFT driving circuit 100 may be used as the driving node 102. The low power supply voltage terminal 104 refers to a VSS (source power supply voltage) voltage terminal, for example, the output voltage of the low power supply voltage terminal 104 may be a negative voltage. The Organic Light-Emitting Diode 200(OLED) refers to an Organic electroluminescent device that emits Light by injecting and recombining carriers under the driving of an electric field through an Organic semiconductor material and a Light-Emitting material. In the display panel, one organic light emitting diode 200 corresponds to one pixel. Based on the anode of the organic light emitting diode 200 for connecting to the driving node 102 of the TFT driving circuit 100, the cathode of the organic light emitting diode 200 is connected to the low power voltage terminal 104 of the TFT driving circuit 100, and further the TFT driving circuit 100 can transmit a driving signal to the organic light emitting diode 200 through the driving node 102, so that the organic light emitting diode 200 can emit light.
The auxiliary cathode line 400 may be used to reduce the display voltage Drop (IR Drop) caused by the large resistance of the front cathode due to the special material or the thin film thickness of the front cathode in the display panel. To address this case induced voltage Drop (IR Drop), an in-plane auxiliary cathode line 400 may be used to reduce cathode induced voltage Drop by bridging in parallel with the in-plane cathode. Diode device 300 refers to an electronic device made of a semiconductor material (silicon, selenium, germanium, etc.). The test current signal is a high current signal. The output terminal of the auxiliary cathode line 400 is connected to the anode of the diode device 300, and the input terminal of the auxiliary cathode line 400 is configured to receive the test current signal, so that in the aging process of the organic light emitting diode 200, the test current signal with a large current can flow in from the auxiliary cathode line 400, flow through the added diode device 300 and the organic light emitting diode 200, and avoid the TFT device in the TFT driving circuit 100, thereby eliminating the negative effect of the large current on the TFT device.
The connection part 500 refers to an insulating film layer between the cathode of the display panel and the auxiliary cathode line 400, i.e., the connection part 500 is disposed between the low power voltage terminal 104 of the TFT driving circuit 100 and the auxiliary cathode line 400. In the aging test process, the connection part 500 is kept in an off state, that is, a path between the auxiliary cathode line 400 and the low power supply voltage end 104 of the TFT driving circuit 100 is disconnected, so that the auxiliary cathode line 400 transmits a test current signal with a large current to the organic light emitting diode 200, and a TFT device in the TFT driving circuit 100 is avoided, thereby implementing the aging test on the organic light emitting diode 200, and simultaneously eliminating negative effects of the large current on the TFT device. After the aging test is completed, the connection part 500 is short-circuited, that is, the connection part 500 is turned on, so that a path between the auxiliary cathode line 400 and the low power voltage end 104 of the TFT driving circuit 100 is turned on, and further, the driving node 102 of the TFT driving circuit 100 can transmit a driving signal to the organic light emitting diode 200, so as to realize normal lighting and light emission of the organic light emitting diode 200.
In the above embodiment, the anode of the organic light emitting diode 200 is used to connect the driving node 102, and the cathode of the organic light emitting diode 200 is connected to the low power voltage terminal 104; the cathode of the diode device 300 is connected to the anode of the organic light emitting diode 200; an output of the auxiliary cathode line 400 is connected to an anode of the diode device 300, and an input of the auxiliary cathode line 400 is configured to receive the test current signal; a connection part 500 is arranged between the low power supply voltage end 104 and the auxiliary cathode line 400; in the burn-in test period, the connection part 500 is opened to allow the auxiliary cathode line 400 to transmit a test current signal to the organic light emitting diode 200; after the aging test period is finished, the connection part 500 is conducted so that the organic light emitting diode 200 can normally work, and further the aging test of the organic light emitting diode 200(OLED) is realized, in the aging test process, the flowing large current can avoid a TFT channel, so that the negative effect of the large current on a TFT device is eliminated, and the normal light emitting of the organic light emitting diode 200 cannot be influenced after the aging test is finished. According to the OLED drive circuit, the diode device 300 is additionally arranged between the anode of the organic light emitting diode 200 and the auxiliary cathode line 400, the auxiliary cathode line 400 is used as a flowing path of large current, and a TFT channel is avoided, so that the negative influence of the large current on the TFT is eliminated, the irreversible influence of the large current on the function and the stability of the TFT device in an OLED aging test is avoided, and the reliability of the OLED drive circuit is improved.
In one example, after the aging test period is finished, the connection portion 500 is turned on based on laser, that is, the auxiliary cathode line 400 and the cathode are welded together in a plane, so that the connection portion 500 is short-circuited, that is, the connection portion 500 is turned on, so that a path between the auxiliary cathode line 400 and the low power voltage end 104 of the TFT driving circuit 100 is turned on, and then the driving node 102 of the TFT driving circuit 100 can transmit a driving signal to the organic light emitting diode 200, thereby realizing normal lighting and light emitting of the organic light emitting diode 200.
In one example, as shown in fig. 3, the TFT driving circuit 100 further includes a high power supply voltage terminal 106, a first transistor 108, a second transistor 112, a third transistor 114, and a capacitive element 116. A first terminal of the first transistor 108 is connected to the high power supply voltage terminal 106, a second terminal of the first transistor 108 is connected to the driving node 102, and a gate of the first transistor 108 is connected to a second terminal of the second transistor 112; a first terminal of the second transistor 112 is used for connecting a data line, and a gate of the second transistor 112 is used for receiving a first scan signal; a first terminal of the third transistor 114 is used for connecting a sensing line, a second terminal of the third transistor 114 is used for connecting the driving node 102, and a gate of the third transistor 114 is used for receiving a second scan signal; a first terminal of the capacitor element 116 is connected to the gate of the first transistor 108, and a second terminal of the capacitor element 116 is connected to the driving node 102.
The high power supply voltage terminal 106 refers to a VDD (drain power supply voltage) voltage terminal, for example, the output voltage of the high power supply voltage terminal 106 may be a positive voltage. The first Transistor 108 may be a TFT device (Thin Film Transistor); the second transistor 112 may be a TFT device and the third transistor 114 may be a TFT device. Illustratively, the first transistor 108, the second transistor 112, and the third transistor 114 are each an N-type thin film transistor. It should be noted that the first transistor 108, the second transistor 112, and the third transistor 114 may also be P-type thin film transistors, respectively. The capacitive element 116 may be used for charging and discharging.
The second transistor 112 is connected to the gate of the first transistor 108 based on the second terminal of the second transistor 112, the first terminal of the second transistor 112 is used for connecting a Data line (Data), the gate of the second transistor 112 is used for receiving a first scanning signal (WR signal), and the second transistor 112 can communicate the Data line Data with the gate of the first transistor 108 in response to the first scanning signal WR. The second transistor 112 may transfer the data voltage of the data line to the capacitive element 116 during a period in which the first scan signal WR has an on voltage. A first terminal of the capacitor 116 is connected to the gate of the first transistor 108, and a second terminal of the capacitor 116 is connected to the driving node 102. The capacitive element 116 may store a Data voltage transferred from a Data line (Data) through the second transistor 112. Based on that the first terminal of the third transistor 114 is used for connecting the sensing line, the second terminal of the third transistor 114 is used for connecting the driving node 102, and the gate of the third transistor 114 is used for accessing the second scan signal; the third transistor 114 may communicate a sensing line (sense) with the driving node 102 in response to the second scan signal RD. The third transistor 114 may transmit a sensing voltage of a sensing line (sense) to the driving node 102 during a period in which the second scan signal RD has an on voltage.
A first terminal of the first transistor 108 is connected to the high power supply voltage terminal 106, a second terminal of the first transistor 108 is connected to the driving node 102, and a gate of the first transistor 108 is connected to a second terminal of the second transistor 112; the first transistor 108 may generate a driving current based on the data voltage stored in the capacitor 116, such that the first terminal and the second terminal of the first transistor 108 are turned on, and thus the organic light emitting diode 200 may be driven to be turned on, and thus the organic light emitting diode 200 may emit light based on the driving current generated by the first transistor 108.
In the above embodiment, the diode device 300 is additionally arranged between the anode of the organic light emitting diode 200 and the auxiliary cathode line 400, and the normal light emission of the organic light emitting diode 200 is not affected based on the principle of unidirectional conduction of the diode. The auxiliary cathode circuit 400 is used as a flowing path of large current, a TFT channel is avoided, negative effects of the large current on the TFT are eliminated, irreversible effects of the large current on the function and stability of a TFT device in an OLED aging test are avoided, the large current aging test on the organic light-emitting diode 200 is realized on the premise of not influencing the function of the TFT device, the reliability of an OLED drive circuit is improved, and the reliability during display is further improved.
In one embodiment, as shown in fig. 4, the present application provides a display panel comprising: a substrate 600, a circuit layer 700, and an encapsulation layer 800; the circuit layer 700 is disposed on the substrate 600; the package layer 800 covers the circuit layer 700; the circuit layer 700 is provided with any one of the above OLED driving circuits.
For the details of the OLED driving circuit, reference may be made to the description of the OLED driving circuit in the above embodiments, and details are not repeated herein.
The substrate 600 can be used for supporting raw materials, the material of the substrate 600 can be a hard material similar to glass, and can also be a flexible material similar to PET, and the materials can be flexibly selected according to the actual production requirement. The circuit layer 700 may be disposed on the substrate 600, and the circuit layer 700 may include an OLED driving circuit, a signal line, and the like; the circuit layer 700 may also include an insulating member. The OLED driving circuit on the circuit layer 700 may be used to drive the organic light emitting diode to operate. The circuit layer 700 is closely attached to the substrate 600.
The encapsulation layer 800 may be disposed on the circuit layer 700, and the encapsulation layer 800 may cover the circuit layer 700, thereby being able to protect the circuit layer 700 from external moisture and oxygen. Note that the encapsulation layer 800 is closely attached to the circuit layer 700. The material of the encapsulation layer 800 includes, for example, silicon oxide, silicon nitride, silicon oxynitride, oxides formed from ethyl silicate TEOS, phosphosilicate glass PSG, borophosphosilicate glass BPSG, low K dielectric materials having a dielectric constant K of less than 3.9, organic insulating materials such as acrylic resins, epoxy resins, phenolic resins, polyamide resins, polyimide resins, and the like, other suitable dielectric materials, or combinations thereof. Illustratively, the low-K dielectric material includes fluorosilicate glass FSG, carbon-doped silicon oxide, polyimide, and the like, and combinations thereof. The packaging layer 800 is arranged, so that interference of the external environment on the operation of the OLED device is avoided, and the stability of the operation of the OLED device is improved.
In the above embodiment, the circuit layer 700 is disposed between the substrate 600 and the package board, the circuit layer 700 includes an OLED driving circuit, an anode of the organic light emitting diode is used for connecting a driving node, and a cathode of the organic light emitting diode is connected to the low power voltage terminal; the cathode of the diode device is connected with the anode of the organic light-emitting diode; an output end of the auxiliary cathode line is connected with an anode of the diode device, and an input end of the auxiliary cathode line is configured to receive the test current signal; a connecting part is arranged between the low power supply voltage end and the auxiliary cathode circuit; in the aging test period, the connecting part is disconnected, so that the auxiliary cathode line transmits a test current signal to the organic light emitting diode; after the aging test period is finished, the connecting part is conducted so that the organic light emitting diode can normally work, further the aging test of the Organic Light Emitting Diode (OLED) is realized, in the aging test process, the flowing large current can avoid a TFT channel, the negative effect of the large current on a TFT device is eliminated, and the normal light emitting of the organic light emitting diode cannot be influenced after the aging test is finished. A diode device is additionally arranged between the anode of the organic light-emitting diode and the auxiliary cathode line, the auxiliary cathode line is used as a flowing path of large current, and a TFT (thin film transistor) channel is avoided, so that the negative influence of the large current on the TFT is eliminated, the irreversible influence of the large current on the function and the stability of the TFT device in an OLED (organic light emitting diode) aging test is avoided, and the reliability of an OLED drive circuit is improved.
In one example, the circuit layer 700 includes an auxiliary cathode line layer and a cathode layer; the auxiliary cathode line layer is disposed adjacent to the substrate 600, and the cathode layer is disposed adjacent to the encapsulation layer 800; the auxiliary cathode line layer is provided with an auxiliary cathode line, and the cathode layer is provided with a low power supply voltage end.
The auxiliary cathode line layer is close to the substrate 600 side, the cathode layer is close to the encapsulation layer 800 layer, and in the process of manufacturing the film layer of the diode, some film layers which are almost not conductive are inevitably added between the auxiliary cathode line layer and the cathode layer, so that a connecting part is formed between the cathode layer of the display panel and the auxiliary cathode line. In the aging test process, the connecting part is kept in a disconnected state, namely, a passage between the auxiliary cathode line of the auxiliary cathode line layer and the low power supply voltage end of the cathode layer is disconnected, so that the auxiliary cathode line transmits a high-current test current signal to the organic light-emitting diode, a TFT device in the TFT driving circuit is avoided, the aging test of the organic light-emitting diode is realized, and meanwhile, the negative influence of the high current on the TFT device can be eliminated. After the aging test is completed, the auxiliary cathode line and the cathode layer can be welded together in the surface by adopting a laser process, so that the connecting part is short-circuited, namely, the connecting part is conducted, the passage between the auxiliary cathode line and the low power supply voltage end of the TFT driving circuit is conducted, and then the driving node of the TFT driving circuit can transmit a driving signal to the organic light-emitting diode, and the organic light-emitting diode is normally lightened to emit light.
In one example, the display panel further includes a buffer layer disposed between the substrate 600 and the circuit layer 700.
Wherein a buffer layer is disposed between the substrate 600 and the circuit layer 700, and the buffer layer can be used to protect the circuit layer 700 and the whole structure of the display panel.
In one embodiment, as shown in fig. 5, there is provided a method of manufacturing a display panel, including:
in step S510, a substrate is provided.
For example, the substrate may be a glass substrate. The substrate may be pre-prepared, for example by deposition.
Step S520, preparing a circuit layer on the substrate; wherein the OLED driving circuit as any one of the above is prepared in the circuit layer.
A circuit layer may be prepared on the substrate by a low temperature polysilicon process. The circuit layer may include a first gate insulating layer, a second gate insulating layer, an interlayer dielectric layer, and a planarization layer. The method includes preparing a first gate insulating layer on a substrate, preparing a second gate insulating layer on the first gate insulating layer, preparing an interlayer dielectric layer on the second gate insulating layer, and preparing a planarization layer on the interlayer dielectric layer. The first gate insulating layer, the second gate insulating layer, the interlayer dielectric layer and the planarization layer form a circuit layer in combination. Illustratively, the first gate insulating layer, the second gate insulating layer, the interlayer dielectric layer, and the planarization layer may be sequentially formed on the base layer by a low temperature polysilicon process.
In the process of preparing the first gate insulating layer and the second gate insulating layer, the first gate insulating layer and the second gate insulating layer need to be respectively subjected to photoetching through a photomask, and light holes are formed in corresponding regions. In the preparation process of the interlayer dielectric layer and the planarization layer, the interlayer dielectric layer and the planarization layer also need to be respectively provided with an anti-overflow groove and a light transmission hole in corresponding areas through a photolithography technology.
In one example, a polysilicon cell is fabricated within a first gate insulating layer, a first gate cell is fabricated within a second gate insulating layer, a second gate cell is fabricated within an interlayer dielectric layer, and an active drain cell is fabricated within a planarization layer. It should be noted that the source and drain units may sequentially pass through the interlayer dielectric layer, the first gate insulating layer and the second gate insulating layer to be electrically connected to the polysilicon unit.
In one example, an auxiliary cathode line layer is prepared on the planarization layer, a light emitting layer is prepared on the auxiliary cathode line layer, and a cathode layer is prepared on the light emitting layer.
The cathode layer may be made of, but not limited to, metal materials such as aluminum, copper, and silver, or transparent conductive materials such as Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO), but not limited to these materials, and may be a single-layer film structure or a multi-layer film stacked structure. The auxiliary cathode line layer may be made of, but not limited to, metal materials such as aluminum, copper, and silver, and may also be made of transparent conductive materials such as Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO).
Step S530, an encapsulation layer is prepared on the circuit layer.
An encapsulation layer may be prepared over the circuit layer using a deposition process, and the encapsulation layer may cover the circuit layer, thereby protecting the circuit layer from external moisture and oxygen. The encapsulation layer is closely attached to the circuit layer. The material of the encapsulation layer includes, for example, silicon oxide, silicon nitride, silicon oxynitride, oxides formed from ethyl silicate TEOS, phosphosilicate glass PSG, borophosphosilicate glass BPSG, low K dielectric materials having a dielectric constant K of less than 3.9, organic insulating materials such as acrylic resins, epoxy resins, phenolic resins, polyamide resins, polyimide resins, and the like, other suitable dielectric materials, or combinations thereof. Illustratively, the low-K dielectric material includes fluorosilicate glass FSG, carbon-doped silicon oxide, polyimide, and the like, and combinations thereof. The encapsulation layer is arranged, so that interference of the external environment on the operation of the organic light-emitting diode is avoided, and the stability of the operation of the organic light-emitting diode is improved.
Step S540, in the aging test period, the connection part of the OLED drive circuit is kept disconnected, so that the auxiliary cathode line of the OLED drive circuit transmits a test current signal to the organic light-emitting diode; and after the aging test time period is ended, the connecting part is conducted.
In the aging test process, the connecting part is kept in a disconnected state, namely, a passage between the auxiliary cathode line of the auxiliary cathode line layer and the low power supply voltage end of the cathode layer is disconnected, so that the auxiliary cathode line transmits a high-current test current signal to the organic light-emitting diode of the light-emitting layer, a TFT device in the circuit layer is avoided, the aging test of the organic light-emitting diode is realized, and meanwhile, the negative influence of the high current on the TFT device can be eliminated. After the aging test is completed, the connecting part is in short circuit, namely the connecting part is conducted, so that a path between the auxiliary cathode line and the low power supply voltage end of the cathode layer is conducted, a driving node of the TFT driving circuit of the circuit layer can transmit a driving signal to the organic light-emitting diode, and the organic light-emitting diode is normally lightened to emit light.
In the embodiment, the diode device is additionally arranged between the anode of the organic light emitting diode and the auxiliary cathode line, and the auxiliary cathode line is used as a flowing path of large current, so that a TFT (thin film transistor) channel is avoided, the negative influence of the large current on the TFT is eliminated, the irreversible influence of the large current on the function and the stability of the TFT device in an OLED (organic light emitting diode) aging test is avoided, and the reliability of the display panel is improved.
In one embodiment, an electronic device is also provided, which includes the above switching power supply.
For specific contents of the silicon carbide MOSFET driving circuit and the switching power supply, reference may be made to the description of the silicon carbide MOSFET driving circuit and the switching power supply in the foregoing embodiments, and details are not repeated here.
In one example, after the burn-in test period ends, the step of turning on the connection part includes:
after the aging test time period is finished, the connecting part is welded based on laser welding so as to be conducted.
Wherein, after the ageing test period, be about to supplementary cathode line and negative pole butt fusion in the face together based on laser butt fusion connecting portion for the connecting portion short circuit, turn on connecting portion promptly, make the supplementary cathode line on supplementary cathode line layer and the low supply voltage end of cathode layer between the route switch on, and then make TFT drive circuit's drive node can transmit drive signal to organic light emitting diode, realize giving out light to organic light emitting diode's normal lighting.
In one embodiment, there is provided a display device including the display panel of any one of the above.
The display panel may be, but is not limited to, a large-sized top emission AMOLED display panel. For specific contents of the display panel and the OLED driving circuit, reference may be made to the descriptions of the display panel and the OLED driving circuit in the foregoing embodiments, and further description is omitted here.
In the embodiment, the high-current aging test can be performed on the organic light emitting diode OLED on the premise of not influencing the function of the TFT device, so that the reliability during the display period is improved.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples are merely illustrative of several embodiments of the present application, and the description is more specific and detailed, but not to be construed as limiting the scope of the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. An OLED drive circuit, comprising:
a TFT drive circuit including a drive node and a low supply voltage terminal;
the anode of the organic light-emitting diode is used for being connected with the driving node, and the cathode of the organic light-emitting diode is connected with the low power supply voltage end;
a diode device, wherein the cathode of the diode device is connected with the anode of the organic light emitting diode;
an auxiliary cathode line having an output connected to the anode of the diode device, an input configured to receive a test current signal;
wherein a connecting part is arranged between the low power supply voltage end and the auxiliary cathode circuit; during the aging test period, the connection part is disconnected, so that the auxiliary cathode line transmits the test current signal to the organic light emitting diode; and after the aging test time period is ended, the connecting part is conducted.
2. The OLED driving circuit according to claim 1, wherein the connection portion is turned on based on laser light after the aging test period is over.
3. The OLED drive circuit according to claim 1, wherein the TFT drive circuit further includes a high power supply voltage terminal, a first transistor, a second transistor, a third transistor, and a capacitive element;
a first terminal of the first transistor is connected to the high power supply voltage terminal, a second terminal of the first transistor is connected to the driving node, and a gate of the first transistor is connected to a second terminal of the second transistor; the first terminal of the second transistor is used for connecting a data line, and the grid electrode of the second transistor is used for accessing a first scanning signal; a first terminal of the third transistor is used for connecting a sensing line, a second terminal of the third transistor is used for connecting the driving node, and a gate of the third transistor is used for accessing a second scanning signal; the first end of the capacitor element is connected with the grid electrode of the first transistor, and the second end of the capacitor element is connected with the driving node.
4. The OLED driving circuit according to claim 3, wherein the first transistor, the second transistor and the third transistor are N-type thin film transistors respectively.
5. A display panel, comprising:
a substrate;
the circuit layer is arranged on the substrate;
the packaging layer covers the circuit layer;
wherein the circuit layer is provided with the OLED driving circuit of any one of claims 1 to 4.
6. The display panel according to claim 5, wherein the circuit layer comprises an auxiliary cathode wiring layer and a cathode layer; the auxiliary cathode circuit layer is arranged close to the substrate, and the cathode layer is arranged close to the packaging layer; the auxiliary cathode line layer is provided with an auxiliary cathode line, and the cathode layer is provided with a low power supply voltage end.
7. The display panel according to claim 5, further comprising a buffer layer provided between the substrate and the circuit layer.
8. A method for manufacturing a display panel, comprising:
providing a substrate;
preparing a circuit layer on the substrate;
preparing an encapsulation layer on the circuit layer;
wherein the OLED driving circuit according to any one of claims 1 to 4 is prepared in the circuit layer; keeping the connection part of the OLED driving circuit disconnected in a burn-in test period so that the auxiliary cathode line of the OLED driving circuit transmits a test current signal to the organic light emitting diode; and after the aging test time period is ended, the connecting part is conducted.
9. The method according to claim 8, wherein the step of turning on the connection portion after the burn-in test period is completed comprises:
and after the aging test time period is finished, the connecting part is welded based on laser welding so as to be conducted.
10. A display device characterized by comprising the display panel of any one of claims 5 to 7.
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| CN114373427B (en) | 2022-12-06 |
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