CN113540157A

CN113540157A - Display panel, manufacturing method thereof and display device comprising display panel

Info

Publication number: CN113540157A
Application number: CN202010294314.2A
Authority: CN
Inventors: 盛翠翠; 黄飞; 王程功; 郭恩卿
Original assignee: Chengdu Vistar Optoelectronics Co Ltd
Current assignee: Chengdu Vistar Optoelectronics Co Ltd
Priority date: 2020-04-15
Filing date: 2020-04-15
Publication date: 2021-10-22

Abstract

The invention provides a display panel, a manufacturing method thereof and a display device comprising the display panel. The display panel comprises a driving backboard and a device structure arranged on the driving backboard; the device structure comprises at least one LED unit and at least one OLED unit, wherein the LED unit comprises a first electrode and a second electrode, and the first electrode and the second electrode are arranged on the same side of the LED unit and face the driving back plate. According to the invention, the first electrode and the second electrode of the LED are arranged on the same side of the LED and face the driving back plate, and synchronous preparation with the OLED common electrode is not needed, so that the process step of flattening the filling material is not needed, the process difficulty is greatly reduced, and the electrical property of the LED is not influenced; meanwhile, the LED dead pixel is easy to detect and repair, and the product yield is greatly improved.

Description

Display panel, manufacturing method thereof and display device comprising display panel

Technical Field

The invention relates to the technical field of display, in particular to a display panel, a manufacturing method thereof and a display device comprising the display panel.

Background

The OLED display panel has excellent display performance, self-luminescence, simple structure, ultra-lightness, thinness, wide viewing angle, low power consumption, and flexible display, and has become the dominant force of the third generation display panel in the display technology field. However, the light emitting life of the OLED display panel has been a bottleneck, and therefore, it is an urgent problem to improve the life of the entire OLED display panel.

Disclosure of Invention

The invention aims to solve the technical problems of high process difficulty, low yield and incapability of repairing in the prior art, and provides a display panel which can reduce the process difficulty, has high yield and is easy to repair when a defective pixel exists, a manufacturing method thereof and a display device comprising the display panel.

In order to solve the above technical problem, the present invention provides a display panel, which includes a driving backplane and a device structure disposed on the driving backplane; the device structure comprises at least one LED unit and at least one OLED unit, wherein the LED unit comprises a first electrode and a second electrode, and the first electrode and the second electrode are arranged on the same side of the LED unit and face the driving back plate.

In an embodiment of the invention, a plurality of first bonding PADs and second bonding PADs are arranged on one side of the driving back plate close to the device structure at intervals, and the first bonding PADs are electrically connected with the first electrodes and the second electrodes of the LED units respectively; the second binding PAD serves as an anode layer of the OLED unit.

In an embodiment of the present invention, the first bound PAD and the second bound PAD are disposed on the same layer, and preferably, the materials of the first bound PAD and the second bound PAD are the same.

In one embodiment of the invention, a cathode layer is arranged on one side of the device structure far away from the driving back plate, and the orthographic projection of the cathode layer on the driving back plate is not overlapped with the orthographic projection of the LED unit on the driving back plate.

In one embodiment of the invention, an insulating layer is arranged on one side of the LED unit away from the driving back plate, and a cathode layer is arranged on one side of the device structure away from the driving back plate, and covers the insulating layer.

The invention also provides a manufacturing method of the display panel, which comprises the following steps: providing a driving back plate, wherein a plurality of first binding PADs and second binding PADs which are arranged at intervals are arranged on the driving back plate; fixing an LED unit on the driving back plate through the first binding PAD, wherein the LED unit comprises a first electrode and a second electrode, and the first electrode and the second electrode are arranged on the same side of the LED unit and face the driving back plate; manufacturing and forming an OLED unit on the second binding PAD; and (6) packaging.

In one embodiment of the present invention, the fixing the LED unit on the driving backplane through the first bonding PAD includes: and fixing the first electrode and the second electrode on the driving back plate in a metal bonding mode or a conductive adhesive connection mode.

In an embodiment of the present invention, the fixing the LED unit on the driving backplane through the first bonding PAD further includes: and transferring the LED units onto the driving back plate through a transfer head.

In an embodiment of the present invention, before forming the OLED unit on the second bonded PAD, the method further includes: and detecting whether the LED unit is damaged or not, and if so, repairing the damaged LED unit.

The invention also provides a display device comprising the display panel.

The device structure provided by the invention comprises at least one LED unit and at least one OLED unit, wherein the first electrode and the second electrode of the LED unit are arranged on the same side of the LED unit and face the driving backboard; in addition, the first electrode and the second electrode of the LED unit are arranged on one side facing the driving backboard, so that the electrical property of the LED unit is not influenced when the electrodes of the OLED unit are evaporated. Moreover, the first electrode and the second electrode of the LED unit are arranged on the same side of the LED unit and face the driving back plate, and are LED out through the first electrode and the second electrode of the first binding PAD on the driving back plate respectively, so that the LED unit can be prepared on the driving back plate in the process, the first electrode and the second electrode of the LED unit can be electrified to detect a dead pixel after the preparation is completed, the dead pixel can be timely repaired, and the product yield is greatly improved.

Drawings

In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which

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

FIG. 2 is a schematic diagram of an embodiment of an LED unit structure according to the present invention;

FIG. 3 is a schematic diagram of an embodiment of an OLED cell structure according to the present invention.

The specification reference numbers indicate: 10-driving backplane, 11-planarization layer, 12-pixel definition layer, 13-first binding PAD, 13A-first electrode of first binding PAD, 13B-second electrode of first binding PAD, 14-second binding PAD, 20-LED unit, 21-first electrode of LED unit, 22-second electrode of LED unit, 30-OLED unit, 31-cathode layer, 301-red OLED, 302-green OLED, 40-extraction electrode.

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention. In the present invention, the LED refers to a "Light Emitting Diode", the Organic LED and the inorganic LED refer to an Organic Light Emitting Diode and an inorganic Light Emitting Diode, respectively, if only an LED is present, the inorganic Light Emitting Diode is referred to, and the OLED refers to an Organic Light Emitting Diode (Organic Light Emitting Diode).

The inventor finds that: the lifetime of the display panel is mainly limited by the blue light emitting material, and no blue light emitting material with a sufficiently long lifetime has been found so far, and since the light emitting efficiency and the light emitting lifetime of the OLED light emitting material are mainly affected by the blue light emitting material, the problem can be solved by adopting the LED and OLED mixed light emitting display. For example, LEDs are used for blue light to emit light, while OLED materials are used for red and green light to emit light. In addition, the prior art discloses a display device integrating inorganic LEDs and organic LEDs into a single chip, in which the inorganic LEDs and the organic LEDs are located in different layers, and the process includes fabricating a driving circuit on a driving backplane, fabricating the inorganic LEDs on the driving backplane, electrically connecting lower contact metal pads of the inorganic LEDs to the driving circuit, filling gaps between the inorganic LEDs with a filling material to form a first filling material layer, and making a top surface of the first filling material layer flat. Then, an organic LED is manufactured on the first filling material layer, a lower contact metal pad of the organic LED is electrically connected to the driving circuit through a through hole of the first filling material layer, then, a filling material is used for filling a gap between the organic LEDs to form a second filling material layer, and finally, a common electrode of the inorganic LED and the organic LED is manufactured. According to the scheme, after the inorganic LED is jointed to the driving back plate, in order to be synchronously prepared with the organic LED common electrode, the flattening filling material is arranged, the adhesion between the electrode and the filling material is poor, the process difficulty is high, and the product yield is low. In addition, because the inorganic LED and the organic LED in the prior art need to be synchronously prepared by the common electrode, it is impossible to detect whether the LED is good or not before the common electrode is made, but after the common electrode is prepared, the inorganic LED is covered by the filling material, so that the inorganic LED cannot be repaired basically even if the inorganic LED is found to have a defect, and even if the inorganic LED can be repaired, the repair difficulty is very high.

In order to solve the above problem, as shown in fig. 1, the inventors provide a display panel including a driving backplane 10 and a device structure disposed on the driving backplane 10; the device structure comprises at least one LED unit 20 and at least one OLED unit 30, the LED unit 20 comprises a first electrode 21 and a second electrode 22, the first electrode 21 and the second electrode 22 are arranged on the same side of the LED unit 20 and face the driving backplane 10.

In one embodiment shown in fig. 1, one LED unit 20 and two OLED units 30 on the device structure together constitute one light emitting unit. A plurality of light emitting cells may be disposed on one driving backplate 10. When the display panel of the present embodiment is applied to a display, one light emitting unit corresponds to one display pixel, different colors can be displayed by a combination of the LED unit 20 and the OLED unit 30 in the light emitting unit, and a plurality of light emitting units collectively display an image.

In the present invention, the first electrode 21 of the LED unit 20 and the second electrode 22 of the LED unit 20 are on the same side of the LED unit 20, i.e. the LED unit 20 is flip-chip mounted on the driving back plate 10, so that there is no need to make an upper electrode in synchronization with the OLED unit 30, and there is no need to perform a process step of planarizing the filling material, thereby greatly reducing the process difficulty.

As shown in fig. 1 and 2, in one embodiment of the present invention, a plurality of first bonding PADs 13 and second bonding PADs 14 are disposed at intervals on a side of the driving backplane 10 close to the device structure, the first bonding PADs 13 are used for the LED unit 20, the second bonding PADs 14 are used for the OLED unit 30, wherein a plurality of the first bonding PADs 13 are electrically connected to the first electrode 21 and the second electrode 22 of the LED unit 20, respectively; the second binding PAD14 serves as an anode layer for the OLED cell 30. The first bonding PAD13 includes a first electrode (Anode)13A of the first bonding PAD and a second electrode (Cathode)13B of the first bonding PAD, and the first electrode 21 and the second electrode 22 of the LED unit 20 are electrically connected to the first electrode 13A of the first bonding PAD and the second electrode 13B of the first bonding PAD, respectively. In the present embodiment, the lead-out electrode 40 is disposed on the side of the driving backplane 10 away from the LED unit 20, and the first bonding PAD13 on the driving backplane 10 penetrates through the driving backplane 10 and is electrically connected to the lead-out electrode 40. As a preferred way, the projection of the first bonded PAD13 through the portion of the driving backplane 10 in the direction perpendicular to the display panel is in a V-shape.

The first bound PAD13 and the second bound PAD14 are disposed on the same layer, and preferably, the first bound PAD13 and the second bound PAD14 are made of the same material. Further, the first and second bound

PADs

13 and 14 are made of a metal material. In addition, the first electrode 13A of the first bonding PAD and the second electrode 13B of the first bonding PAD on the driving backplane 10 may be deposited by the same metal layer. Namely, the first electrode 13A of the first bonding PAD and the second electrode 13B of the first bonding PAD are directly deposited on the driving back plate 10 at the same time; alternatively, a metal layer may be deposited on the driving backplate 10, and then the metal layer is etched to separate the metal layer into a plurality of portions, each serving as the first electrode 13A of the first bonding PAD or the second electrode 13B of the first bonding PAD. Of course, in other embodiments, the first electrode of the first bonded PAD and the second electrode of the first bonded PAD may be made by other methods.

In the present embodiment, the LED unit 20 is provided in the form of an LED chip, the first electrode 21 and the second electrode 22 of the LED unit are prepared on the LED chip in advance, and then the first electrode 21 and the second electrode 22 of the LED chip are fixed on the driving back plate 10 by a metal bonding manner or a conductive adhesive connection manner, and are electrically connected to the first electrode 13A of the first bonding PAD and the second electrode 13B of the first bonding PAD on the driving back plate 10, respectively. The metal bonding mode comprises AuIn, AuAu, AuCu bonding and the like. The conductive paste includes ACF, SAP, and the like. In one embodiment, the first electrode 21 of the LED unit 20 may be an anode, and the second electrode 22 of the LED unit may be a cathode; the first electrode of the first bonded PAD may be an anode and the second electrode of the first bonded PAD may be a cathode.

In other embodiments, the first electrode and the second electrode of the LED unit 20 may be directly prepared on the driving back plate 10, and then the LED unit is prepared on the prepared first electrode and second electrode, or the prepared LED unit is attached to the first electrode and the second electrode. In this manner, the first electrode and the second electrode of the LED unit may also be deposited from the same layer of metal. Namely, the first electrode and the second electrode of the LED unit are directly deposited on the driving back plate 10 at the same time; alternatively, a metal layer may be deposited on the driving backplane 10, and then the metal layer is etched to separate the metal layer into a plurality of portions, each serving as the first electrode and the second electrode of the LED unit. Of course, in other embodiments, the first electrode and the second electrode of the LED unit may be manufactured by other methods.

As shown in fig. 3, in the present embodiment, a cathode layer 31 is disposed on a side of the device structure away from the driving back plate 10, and an orthogonal projection of the cathode layer 31 on the driving back plate 10 does not overlap an orthogonal projection of the LED unit 20 on the driving back plate 10. Specifically, in one embodiment, a cathode layer 31 is disposed at a position corresponding to the OLED unit 30 on a side of the device structure away from the driving backplane 10, the OLED unit 30 has the second bonding PAD14 as an anode layer on one side, and the cathode layer 31 is disposed on the other side, wherein the cathode layer 31 avoids the area where the LED unit 20 is located. Since the cathode layer 31 of the OLED unit 30 is formed to avoid the LED unit 20, the electrical property of the LED unit 20 is not affected.

As another embodiment, an insulating layer is disposed on a side of the LED unit 20 away from the driving back plate 10, a cathode layer 31 is disposed on a side of the device structure away from the driving back plate 10, the cathode layer 31 covers the insulating layer, and the LED unit 20 and the cathode layer 31 are separated by the insulating layer, so that the cathode layer 31 does not electrically contact with the LED unit 20, and thus, when the cathode layer 31 is manufactured, the LED unit area does not need to be avoided, which reduces the difficulty of the process.

The second bonding PAD14 may be deposited with the first bonding PAD13 or the first electrode 21 and the second electrode 22 of the LED unit 20 from the same metal layer. Namely, the first bound PAD13 and the second bound PAD14 are deposited directly on the driving backplane 10 at the same time; alternatively, a metal layer may be deposited on the driving backplane 10 and then etched to separate the metal layer into a plurality of portions, each portion serving as the first bonding PAD13 or the second bonding PAD14, respectively. Of course, in other embodiments, the anode layer of the OLED cells may be fabricated by other methods. While the cathode layer of the OLED cells may typically be formed by an evaporation process. Of course, the cathode layer of the OLED cells may be formed in other ways.

Similarly, the second bonded PAD14 of the OLED unit 30 can also be electrically connected to the extraction electrode 40 on the other side of the driving backplane 10 through the driving backplane 10, and further, the projection of the second bonded PAD14 through the portion of the driving backplane 10 in the direction perpendicular to the display panel is in a V shape.

As for the structure of the OLED unit, it generally includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer, in addition to an anode layer and a cathode layer, as in the conventional OLED unit. When the OLED unit with the structure is adopted, the hole injection layer is in contact with the anode layer, and the electron injection layer is in contact with the cathode layer. Of course, the OLED unit may have other structures, and the structure of the OLED unit is not limited in the present invention.

In the embodiment shown in fig. 1-3, the driving backplane 10 comprises a Planarization Layer (PLN)11 at the bottom and a Pixel Definition Layer (PDL)12 above the planarization layer 11, wherein the LED unit 20 and the OLED unit 30 are both located above the planarization layer 11 and between the pixel definition layers 12, i.e. the space between the OLED unit 30 and the OLED unit 20 is filled by the pixel definition layer 12.

In the prior art, the filling material of the planarization layer needs to cover the height difference of the whole LED thickness, and at least needs to have the thickness of 4um-7um, so that the material is wasted, and the cost is high; in the present application, the planarization layer 11 has a thickness of about 2-3um to meet the planarization requirement. Therefore, compared with the prior art, the material is saved and the cost is low.

In the invention, the first electrode 21 of the LED unit 20 and the second electrode 22 of the LED unit are arranged on the same side of the LED unit 20, and the electrodes do not need to be synchronously arranged with the OLED unit 30, so that the LED unit 20 and the OLED unit 30 can be preferentially arranged. After the LED unit 20 is fixed to the driving back plate 10, the first electrode 21 of the LED unit and the second electrode 22 of the LED unit are connected to the driving circuit, and then the LED unit 20 is powered on to detect. Therefore, it is possible to detect whether the LED unit 20 is damaged in time, and if the damaged LED is detected, the damaged LED can be repaired in time, for example, the damaged LED chip is removed and replaced with a new LED chip.

In one embodiment of the present invention, the LED unit 20 is used to emit blue light, one OLED 301 of the two OLED units 30 is used to emit red light, and the other OLED 302 is used to emit green light. For example, in the embodiment shown in fig. 1, one pixel is displayed by using one blue LED unit 20 together with one red OLED unit 301 and one green OLED unit 302, and a plurality of groups of pixels composed of LED units and OLED units are arranged together, thereby displaying an image. The embodiment utilizes the LED unit 20 to replace a blue OLED unit with a short lifetime, so as to greatly prolong the overall lifetime of the display panel, and meanwhile, the embodiment also has the advantages of ultra-light and thin, wide viewing angle, low power consumption and the like of the OLED display panel.

Another embodiment of the present invention provides a display device, including the display panel in any of the above embodiments. The display device can be a mobile phone, a flat panel or a display and other equipment needing content display.

In other embodiments, the display panel of the present invention can also be applied to a lamp, such as a lighting lamp or a decorative lamp. The combination of the LED unit and the OLED unit may allow the lamp to emit light of different colors. When the LED illuminating lamp is used as an illuminating lamp, the color temperature and the brightness of emitted light can be adjusted by adjusting the luminous intensity of each LED unit and each OLED unit so as to meet different requirements. For example, when reading, the electronic device emits soft white light to protect eyes, and when using an electronic device such as a mobile phone, the color temperature of the emitted light is properly increased to reduce the damage of the blue light found on the screen of the electronic device to the eyes. When the LED/OLED decorative lamp is used as a decorative lamp, the decorative lamp can emit different colors by adjusting the light emitting ratio of the LEDs and the OLEDs in each color so as to meet different requirements.

One embodiment of the present invention provides a method for manufacturing a display panel, including the steps of:

providing a driving backboard 10, wherein a plurality of first binding PADs 13 and second binding PADs 14 which are arranged at intervals are arranged on the driving backboard 10;

fixing an LED unit 20 on the driving backplane 10 by the first bonded PAD13, wherein the LED unit 20 comprises a first electrode 21 and a second electrode 22, the first electrode 21 and the second electrode 33 being arranged on the same side of the LED unit 20 and facing the driving backplane 10;

fabricating an OLED cell 30 on the second bonded PAD 14;

and (6) packaging.

In the present embodiment, the LED unit 20 is provided in the form of an LED chip, the LED chip has a first electrode 21 and a second electrode 22, and the first electrode 21 and the second electrode 22 on the LED chip are located on the same side of the LED chip, and the first electrode 21 and the second electrode 22 of the LED unit are fixed on the driving back plate 10 by a metal bonding method or a conductive adhesive connection method.

The fixing the LED unit 20 on the driving backplane 10 by the first binding PAD13 further comprises: the LED units 20 are transferred onto the driving backplane 10 by a transfer head. Specifically, the manner of transferring the LED unit 20 to the driving backplane 10 includes, but is not limited to, utilizing electrostatic attraction, adhesive force, electromagnetic force, van der waals force, and vacuum attraction between the transfer head and the LED unit 20, and may also be a laser transfer technology, a roller transfer technology, and the like, and may be specifically configured according to practical situations.

In the present embodiment, the OLED unit 30 is fabricated by vapor deposition. The cathode layer 31 is also formed by vapor deposition, and when the cathode layer 31 is formed in the region of the OLED cell 30, the cathode layer 31 avoids the region where the LED cell 20 is located, and when the cathode layer 31 of the OLED cell 30 is formed by vapor deposition, the cathode layer 31 avoids the LED cell 20, so that the electrical property of the LED is not affected; or if the LED chip is provided with an insulating layer, the cathode layer 31 does not need to avoid the area where the LED is located. Specifically, a transparent organic glue is coated on the LED chip in a printing mode to play a role of transparency and insulation, and at the moment, the cathode of the OLED chip can not avoid the position of the LED chip.

In the present invention, since the first electrode and the second electrode of the LED unit 20 are disposed on the same side of the LED unit 20, after the LED unit 20 is fixed on the driving back plate 10, the first electrode and the second electrode of the LED are connected to the driving circuit, and at this time, the LED can be detected by powering on, for example, by using ultraviolet detection, PL + AOI detection, contact type photoelectric detection technology or a point-screen lower-shot detection. Therefore, in order to improve the yield of products, the LED unit 20 may be electrified after the step of fixing the LED unit 20 to the driving back plate 10 and before the step of forming the OLED unit 30 to detect whether the LED is damaged, and if the damaged LED unit is detected, the damaged LED unit may be repaired in time, for example, the damaged LED chip may be removed and replaced with a new LED chip.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims

1. A display panel is characterized by comprising a driving backboard and a device structure arranged on the driving backboard;

the device structure comprises at least one LED unit and at least one OLED unit, wherein the LED unit comprises a first electrode and a second electrode, and the first electrode and the second electrode are arranged on the same side of the LED unit and face the driving back plate.

2. The display panel of claim 1, wherein a plurality of first bonding PADs and second bonding PADs are disposed on a side of the driving backplane adjacent to the device structure, and the first bonding PADs are electrically connected to the first electrodes and the second electrodes of the LED units, respectively; the second binding PAD serves as an anode layer of the OLED unit.

3. The display panel of claim 2, wherein the first and second bound PADs are arranged on the same layer, and preferably the first and second bound PADs are made of the same material.

4. The display panel according to any one of claims 1 to 3, wherein a cathode layer is disposed on a side of the device structure away from the driving back plate, and an orthogonal projection of the cathode layer on the driving back plate does not overlap an orthogonal projection of the LED unit on the driving back plate.

5. The display panel according to any one of claims 1 to 3, wherein an insulating layer is disposed on a side of the LED unit facing away from the driving backplane, and a cathode layer is disposed on a side of the device structure facing away from the driving backplane, the cathode layer covering the insulating layer.

6. A manufacturing method of a display panel is characterized by comprising the following steps:

providing a driving back plate, wherein a plurality of first binding PADs and second binding PADs which are arranged at intervals are arranged on the driving back plate;

fixing an LED unit on the driving back plate through the first binding PAD, wherein the LED unit comprises a first electrode and a second electrode, and the first electrode and the second electrode are arranged on the same side of the LED unit and face the driving back plate;

manufacturing and forming an OLED unit on the second binding PAD;

and (6) packaging.

7. The method for manufacturing a display panel according to claim 6, wherein the fixing the LED unit on the driving backplane through the first bonding PAD comprises: and fixing the first electrode and the second electrode on the driving back plate in a metal bonding mode or a conductive adhesive connection mode.

8. The method for manufacturing a display panel according to claim 6, wherein the fixing the LED unit on the driving backplane via the first bonding PAD further comprises: and transferring the LED units onto the driving back plate through a transfer head.

9. The method of claim 6, further comprising, before forming the OLED unit on the second bonded PAD: and detecting whether the LED unit is damaged or not, and if so, repairing the damaged LED unit.

10. A display device comprising the display panel according to any one of claims 1 to 5.