CN110311053A - Display panel and manufacturing method thereof - Google Patents

Abstract

The present invention provides a display panel and a manufacturing method thereof. The manufacturing method includes the following steps: providing a driving backplane and a light-emitting substrate, the driving backplane is provided with a first bonding metal layer, and the light-emitting substrate is provided with There is a second bonding metal layer; the first bonding metal layer of the driving backplane is metal-bonded with the second bonding metal layer of the light-emitting substrate to form a metal bonding layer; patterning the light-emitting substrate and the metal bonding layer to form a pixel array; a thin film encapsulation layer is formed outside the pixel array, and the thin film encapsulation layer completely covers the pixel array; a pixel definition layer is formed on the top of the thin film encapsulation layer, and Quantum dots are formed in the pixel definition layer to form a multi-color display. The display panel and its manufacturing method of the present invention break through the physical limit of high-pixel-density and high-precision metal mask plates, and can realize display with 2000 and higher pixel density.

Description

Display panel and manufacturing method thereof

technical field

The invention relates to a display panel and a manufacturing method thereof, in particular to a display panel with high pixel density and a manufacturing method thereof.

Background technique

Most of the current OLED display body uses evaporation of different OLED materials to achieve OLED patterning. This method is no problem when the pixel density is lower than 700, but when the pixel density is higher than 800, the existing manufacturing technology will enter the physical bottleneck.

Therefore, realizing a colorful display with high pixel density is an urgent technical problem to be solved at present.

Contents of the invention

The object of the present invention is to provide a method for manufacturing a display panel, which forms quantum dots in the pixel definition layer, and can realize multi-color display of a high-resolution display panel.

In order to achieve the above object, the present invention provides a method for manufacturing a display panel, which mainly includes the following steps:

Provide a driving backplane and a light-emitting substrate, the driving backplane is provided with a first bonding metal layer, and the light-emitting substrate is provided with a second bonding metal layer;

performing metal bonding on the first bonding metal layer of the driving backplane and the second bonding metal layer of the light-emitting substrate to form a metal bonding layer;

patterning the light-emitting substrate and the metal bonding layer to form a pixel array;

forming a thin film encapsulation layer outside the pixel array, the thin film encapsulation layer completely covering the pixel array;

A pixel definition layer is formed on top of the thin film encapsulation layer, and quantum dots are formed in the pixel definition layer to form a multi-color display.

As a further improvement of the present invention, the pixel array is formed by yellow light and etching process.

As a further improvement of the present invention, the pixel definition layer is formed by yellow light process and etching process.

As a further improvement of the present invention, while forming the quantum dots in the pixel definition layer, a black matrix is also formed between the quantum dots.

As a further improvement of the present invention, the quantum dots and the black matrix are formed by an electrofluidic printing process.

The purpose of the present invention is also to provide a display panel, which is provided with quantum dots in the pixel definition layer, which can realize multi-color display of the high-resolution display panel.

In order to achieve the above object, the present invention provides a display panel, including a driving backplane, a pixel array arranged on the driving backplane, and a thin film package arranged outside the pixel array and completely covering the pixel array layer, and the display panel further includes a pixel definition layer arranged on top of the thin film encapsulation layer, and quantum dots arranged in the pixel definition layer to form a multi-color display.

As a further improvement of the present invention, the quantum dots include red quantum dots and green quantum dots.

As a further improvement of the present invention, the display panel further includes a black matrix disposed in the pixel definition layer and between the red quantum dots and the green quantum dots.

As a further improvement of the present invention, the display panel further includes an insulating protection layer disposed on the top side of the quantum dots.

As a further improvement of the present invention, the display panel further includes a glass cover, the glass cover is packaged on top of the insulating protection layer and completely covers the insulating protection layer.

The beneficial effects of the present invention are: the manufacturing method of the display panel of the present invention forms a pixel definition layer and quantum dots located in the pixel definition layer on the top of the thin film encapsulation layer, so that the display panel manufactured by this method forms a multi-color display, and further uses yellow The optical and etching process realizes the patterning of high-pixel display panels, breaks through the physical limit of high-pixel-density high-precision metal masks, and can realize displays with 2000 and higher pixel densities.

Description of drawings

FIG. 1 is a schematic diagram of a driving backplane and a light-emitting substrate of a display panel according to the present invention before bonding.

FIG. 2 is a schematic diagram of a driving backplane and a light-emitting substrate of the display panel shown in FIG. 1 after bonding.

FIG. 3 is a schematic diagram of removing the substrate of the light-emitting substrate in FIG. 2 .

FIG. 4 is a schematic diagram of forming a photoresist layer on the display panel shown in FIG. 3 .

FIG. 5 is a schematic diagram of forming a light-emitting array and a corresponding arrangement of metal bonding arrays on the display panel shown in FIG. 4 .

FIG. 6 is a schematic diagram of forming an insulating layer on the metal bonding array corresponding to the light emitting array of the display panel shown in FIG. 5 .

FIG. 7 is a schematic diagram of forming openings on the insulating layer of the display panel shown in FIG. 6 .

FIG. 8 is a schematic diagram of forming a metal layer on the insulating layer of the display panel shown in FIG. 7 .

FIG. 9 is a schematic diagram of forming a thin film encapsulation layer on the display panel shown in FIG. 8 .

FIG. 10 is a schematic diagram of forming a pixel definition layer on top of the thin film encapsulation layer of the display panel shown in FIG. 9 .

FIG. 11 is a schematic diagram of forming quantum dots and a black matrix in the pixel definition layer of the display panel shown in FIG. 10 .

FIG. 12 is a schematic diagram of forming an insulating protection layer on the top side of the quantum dots and the black matrix of the display panel shown in FIG. 11 .

FIG. 13 is a schematic diagram of encapsulating a glass cover on the top side of the insulating protection layer of the display panel shown in FIG. 12 .

Detailed ways

In order to make the purpose, technical solution and effect of the present application more clear and definite, the present application will be further described in detail below with reference to the accompanying drawings and examples.

1-13, the present application provides a method for manufacturing a display panel 100, the following method steps are a preferred implementation of the method for manufacturing the display panel 100, in this embodiment, the display panel 100 The manufacturing method mainly comprises the following steps:

A driving backplane 10 and a light emitting substrate 20 are provided. Wherein, the driving backplane 10 includes a driving circuit array 101 , a first bonding metal layer 31 is disposed on the driving backplane 10 , and a second bonding metal layer 32 is disposed on the light emitting substrate 20 . Specifically, the light-emitting substrate 20 used in this application is based on Micro Light Emitting Diode (Micro-LED) technology, which uses a Multiple Quantum Well (Multiple Quantum Well, MQW) structure to emit light, with high brightness, high response speed, and low power consumption. consumption, long life and other advantages.

Metal bonding is performed between the first bonding metal layer 31 of the driving backplane 10 and the second bonding metal layer 32 of the light emitting substrate 20 to form a metal bonding layer 30 . Wherein, the thickness of the first bonding metal layer 31 and the second bonding metal layer 32 are the same or different, and the thickness of the metal bonding layer 30 formed after bonding may be the thickness of the first bonding metal layer 31 Or twice or three times the thickness of one of the second bonding metal layers 32 . The present invention uses metal bonding to connect the driving backplane 10 and the light-emitting substrate 20. Compared with the existing technology of making Micro-LED devices first and then transferring them to the driving backplane, it avoids the problems in batch transfer. Alignment accuracy and other issues.

The light-emitting substrate 20 and the metal bonding layer 30 are patterned to form a required pixel array 210 and a metal bonding array 301 corresponding to the pixel array 210, and the metal bonding array 301 can be used as an anode. Wherein, the light-emitting substrate 20 and the metal bonding layer 30 can be patterned by using yellow light and etching process to form the required pixel array 210 and metal bonding array 301 . Compared with the existing scheme of using a mask plate to realize OLED patterning by evaporation process, this application can achieve smaller-sized pixels, and can increase the pixel density (Pixels PerInch, PPI) under the condition of the same display panel size .

A thin film encapsulation layer 60 is formed outside the pixel array 210 , and the thin film encapsulation layer 60 completely covers the pixel array 210 . A pixel definition layer 61 is formed on the top of the thin film encapsulation layer 60, and quantum dots 50 are formed in the pixel definition layer 61, thereby forming a multi-color display.

Quantum dots 50 are formed in at least part of the pixel array 210 in the pixel definition layer 61 to form a multi-color display. Wherein, the light emitted by the light-emitting substrate 20 passes through the quantum dots 50 and emits light of different colors, thereby realizing multi-color display. Specifically, the quantum dots 50 of this embodiment include red quantum dots 51 that can emit red light R, and green quantum dots 52 that can emit green light G, and the light-emitting substrate 20 can directly emit blue light B, thus, the obtained The display panel 100 has RGB three-color display.

The manufacturing method and structure of the display panel 100 of the present application will be described in detail below.

Please refer to FIG. 1 , the drive backplane 10 is provided with a drive circuit array 101 corresponding to the pixel array 210, which is used to electrically connect with the corresponding pixel array 210, so as to provide a drive voltage for the pixel array 210, and then control the pixel array 210. The light emission of the pixel array 210 is described. The driving backplane 10 may be a flexible backplane or a rigid backplane, which is not limited here.

A first bonding metal layer 31 is formed on the driving backplane 10 . Wherein, the material of the first bonding metal layer 31 may be metals such as gold (Au), copper (Cu), gallium (GA), nickel (Ni), or an alloy of these metals, such as a nickel-gold alloy Wait. The formed first bonding metal layer 31 has a thickness of 800-1200 nm. The first bonding metal layer 31 can be formed by deposition or evaporation. Specifically, the deposition method can be selected from atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etc. The way.

The light-emitting substrate 20 includes a substrate 21 and a light-emitting layer 22 disposed on the substrate 21, and the second bonding metal layer 32 is disposed on the other side of the light-emitting layer 22 opposite to the substrate 21. side. The luminescent layer 22 includes a first semiconductor layer 220 sequentially arranged on the substrate 21, a multiple quantum well layer 221 arranged on the first semiconductor layer 220, and a multiquantum well layer 221 arranged on the multiple quantum well layer 221. The second semiconductor layer 222 . The second semiconductor layer 222 is electrically connected to the second bonding metal layer 32 .

In this embodiment, the first semiconductor layer 220 is an N-type semiconductor layer, and the second semiconductor layer 222 is a P-type semiconductor layer. In different embodiments, different semiconductor materials can be selected, for example, N-type gallium nitride (GaN), P-type gallium nitride (GaN), N-type aluminum (Al) doped gallium nitride (AlGaN) ), P-type aluminum (Al)-doped gallium nitride (AlGaN), P-type magnesium (Mg)-doped gallium nitride, N-type silicon (Si)-doped gallium nitride, etc. The multiple quantum well layer 221 may be a gallium nitride quantum well layer composed of indium gallium nitride/gallium nitride (InGaN/GaN) layers arranged repeatedly in sequence. In other implementation manners, the materials of the first semiconductor layer 220 , the second semiconductor layer 222 and the multiple quantum well layer 221 can also be set according to the actual requirements of the display panel, which is not limited here.

The P-type second semiconductor layer 222, the multi-quantum well layer 221, and the N-type first semiconductor layer 220 form a light-emitting PN junction, and the second semiconductor layer 222 and the first semiconductor layer 220 are respectively connected to the electrodes on both sides. For electrical connection, the above light-emitting PN junction can be electrically connected to the driving circuit, so as to apply voltage to the light-emitting PN junction through the driving circuit. When the drive circuit applies a voltage to the light-emitting PN junction, electrons are injected into the multi-quantum well layer 221 in the N-type first semiconductor layer 220, and holes are injected into the multi-quantum well layer 221 in the P-type second semiconductor layer 222. In the quantum well layer 221 ; subsequently, in the multi-quantum well layer 221 , the electrons and the holes recombine to emit photons, completing the conversion of electrical energy into light energy, and realizing the light emission of the light emitting layer 22 .

Among them, because gallium nitride-based materials are difficult to grow directly on a glass substrate, the substrate 21 is generally a sapphire substrate. This is because sapphire has good stability and high mechanical strength, and can be used in the high-temperature growth process. Crystals with better crystal quality can be obtained when crystals are epitaxially grown on sapphire substrates; and the production technology of sapphire substrates is mature, the device quality is better, and it is easy to handle and clean. Of course, in other embodiments, silicon-based substrates (such as silicon carbide (SiC) substrates or silicon (Si) substrates) or gallium nitride (GaN) substrates can also be selected, and other available substrate materials can also be used. , is not limited here.

The material and thickness of the second bonding metal layer 32 and the first bonding metal layer 31 may be the same or different. Preferably, the second bonding metal layer 32 and the first bonding metal layer 31 are made of the same material, so that the bonding strength between the second bonding metal layer 32 and the first bonding metal layer 31 can be enhanced, interlayer separation can be prevented, and the stability of the device can be improved. Likewise, the second bonding metal layer 32 can also be formed by deposition or vapor deposition. For details, please refer to the description of the above-mentioned embodiment, and details will not be repeated here.

Please refer to FIG. 1 and FIG. 2, the first bonding metal layer 31 of the driving backplane 10 is bonded to the second bonding metal layer 32 of the light-emitting substrate 20, and the first The bonding metal layer 31 and the second bonding metal layer 32 are bonded together to form the metal bonding layer 30 .

Please refer to FIG. 3 , which is a schematic diagram of removing the substrate 21 of the light-emitting substrate 20 . When removing the substrate 21 of the light-emitting substrate 20 , the substrate 21 may be peeled off by means such as laser lift-off. Of course, the substrate 21 may also be peeled off by other methods, which are not limited herein.

Please refer to FIG. 4 and FIG. 5. FIG. 4 is a schematic diagram of forming a photoresist layer 223 on the first semiconductor layer 220 after the substrate 21 is removed from the light-emitting substrate 20. FIG. Light emitting substrate 20. Specifically, a photoresist layer 223 is formed on the first semiconductor layer 220 , and then exposed and developed to obtain the photoresist layer pattern, wherein the photoresist layer pattern corresponds to the arrangement of the pixel array 210 . Then use the patterned photoresist layer 223 as a mask to etch the light-emitting substrate 20 and the metal bonding layer 30 to form a light-emitting array 201 and a correspondingly arranged metal bonding array 301. The metal bonding array 301 Can be used as anode. Specifically, the light-emitting substrate 20 and the metal bonding layer 30 can be etched by reactive ion etching (RIE), and the positioning can be performed by using the principle of self-alignment during etching. Certainly, in other implementation manners, other methods may also be selected for etching.

Referring to FIG. 6 , an insulating layer 224 is formed on the light emitting array 201 and the corresponding metal bonding array 301 . The insulating layer 224 covers the light emitting array 201 and the metal bonding array 301 . The thickness of the insulating layer 224 is 50nm. The insulating layer 224 can be selected by means of atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), and the like. The material of the insulating layer 224 can be an inorganic material, and the inorganic material can be one or more of the following materials: Al2O3, TiO2, ZrO2, MgO, HFO2, Ta2O5, Si3N4, AlN, SiN, SiNO, SiO, SiO2, SiC, SiCNx, ITO, IZO, etc.

Referring to FIG. 7 , an opening 225 is formed on the insulating layer 224 . Preferably, the opening 225 can be formed on the insulating layer 224 by using the aforementioned yellow light process and RIE method. The specific method is similar to the above, and will not be repeated here.

Referring to FIG. 8, a metal layer 40 is formed on the insulating layer 224. The thickness of the metal layer 40 is 10nm, which can be obtained by atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD) way to form. The material of the metal layer 40 can be aluminum (Al), silver (Ag), etc., and the metal layer 40 can be used as a cathode.

In this embodiment, the patterning of the pixel array 210 is realized by using yellow light and etching process, so that pixels of smaller size can be manufactured. For example, in this method, the width of the patterned metal bonding layer 30 can be as narrow as 5 μm, the pixel pitch is 24 μm, and the sub-pixel pitch is 8 μm, so that a display panel up to 3000 PPI can be produced. However, the existing method of realizing OLED patterning by vapor deposition of different OLED materials can only achieve 700-800PPI. This is because a high-precision metal mask (Fine Metal Mask, FMM) needs to be used when evaporating OLED materials, but FMM has a physical limit, and the minimum opening pitch can only be 10-15 μm. However, when the present invention uses the yellow light process to pattern the pixel array 210, the distance between the patterns can be at the nanometer level. Through this method, a display panel with a high PPI can be produced with a certain size of the display panel.

Please refer to FIG. 9 , which is a schematic diagram of forming the thin film encapsulation layer 60 . The formed thin film encapsulation layer 60 can completely cover the pixel array 210 to block moisture and oxygen and protect the pixel array 210 . The thin-film encapsulation layer 60 generally includes an organic encapsulation layer and an inorganic encapsulation layer. The inorganic encapsulation layer has good barrier properties to water vapor and oxygen; The formation of the organic encapsulation layer is relatively good at the same time.

Referring to FIG. 10 , a pixel definition layer 61 is formed on the top of the thin film encapsulation layer 60 by using the aforementioned yellow light process and RIE method. The specific method is similar to the above, and will not be repeated here.

Referring to FIG. 11 , quantum dots 50 and a black matrix 70 (Black Matrix, BM) are formed in the pixel definition layer 61 . The quantum dots 50 are disposed right above part of the openings 225 . Specifically, the quantum dots 50 and the black matrix 70 are formed by an electrofluidic printing process. The quantum dots 50 include red quantum dots 51 capable of emitting red light R and green quantum dots 52 capable of emitting green light G. In this embodiment, the emission color of the multi-quantum well layer 221 is blue, so that the emission region not provided with quantum dots 50 can directly emit blue light B to realize RGB three-color display.

Specifically, the multi-quantum well layer 221 is made of inorganic materials, which does not have the problems of short lifetime and poor stability. Especially the multi-quantum well layer 221 based on gallium nitride (GaN) material, GaN, as a wide bandgap semiconductor, has inherent advantages in the blue light emitting part, the luminous efficiency can reach 400lM/w, high brightness, low power consumption, and long life , is the most ideal blue light emitting material.

Referring to FIG. 12 , an insulating protective layer 53 is further formed on top of the quantum dots 50 and the black matrix 70 . The insulating protection layer 53 covers the quantum dots 50 and the black matrix 70 . The thickness of the insulating protection layer 53 is 50nm. The insulating protection layer 53 can be selected by means of atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), and the like. The material of the insulating protection layer 53 can be an inorganic material, and the inorganic material can be one or more of the following materials: Al2O3, TiO2, ZrO2, MgO, HFO2, Ta2O5, Si3N4, AlN, SiN, SiNO, SiO, SiO2 , SiC, SiCNx, ITO, IZO, etc.

Referring to FIG. 13 , a glass cover 80 is further encapsulated on the top of the insulating protection layer 53 , and the glass cover 80 completely covers the insulating protection layer 53 . The glass cover 80 is bonded and fixed by coating UV glue 90 on the periphery of the insulating protection layer 53 to protect the quantum dots 50 .

As mentioned above, the manufacturing method of the display panel 100 provided in this application, combined with the high-resolution drive backplane 10, can realize the manufacture of the high-resolution display panel 100 of 2000PPI and above. PPI's pixel array patterning is no longer limited by the physical limits of FMM. At the same time, a pixel definition layer 61 is formed on the top of the thin film encapsulation layer 60, and red quantum dots 51 and green quantum dots 52 are formed in the pixel definition layer 61 by an electrofluidic printing process to realize red and green light emission, thereby realizing RGB three colors show. In addition, the method provided by this application directly bonds the driving backplane 10 and the light-emitting substrate 20. Compared with the existing technology of making Micro-LED devices first and then transferring them to the driving backplane, it avoids alignment in batch transfer. accuracy issues.

Based on this, the present application also provides a display panel 100, the display panel 100 includes a driving backplane 10, a pixel array 210 disposed on the driving backplane 10, and a pixel array 210 disposed outside the pixel array 210 and The thin film encapsulation layer 60 that completely covers the pixel array 210, the display panel 100 further includes a pixel definition layer 61 disposed on top of the thin film encapsulation layer 60, and quantum dots 50 disposed in the pixel definition layer 61, Further, a multi-color display is formed.

Wherein, the quantum dots 50 include red quantum dots 51 that can emit red light R and green quantum dots 52 that can emit green light G, and the light emission color of the pixel array 210 is blue B, and then RGB three-color display can be realized .

The display panel 100 further includes a black matrix 70 disposed in the pixel definition layer 61 and between the red quantum dots 51 and the green quantum dots 52 .

The display panel 100 further includes an insulating protective layer 53 disposed on the top side of the quantum dots 50 . For the specific structure, please refer to FIG. 12 , and for the specific structure description, please refer to the description of the above-mentioned embodiment, and details will not be repeated here.

The display panel 100 further includes a glass cover 80 , the glass cover 80 is encapsulated on top of the insulating protection layer 53 by UV glue 90 and completely covers the insulating protection layer 53 .

The display panel 100 of the present invention has high PPI and better display effect, and can be used as a display screen of AR and VR devices.

The above is only the implementation of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process conversion made by using the specification and drawings of the application, or directly or indirectly used in other related technologies fields, all of which are equally included in the scope of patent protection of the present invention.

Claims (10)

1. a kind of manufacturing method of display panel, which is characterized in that mainly include the following steps:

Driving backboard and light-emitting substrate is provided, is provided with the first bonding metal layer on the driving backboard, on the light-emitting substrate It is provided with the second bonding metal layer；

Second bonding metal layer of the first bonding metal layer of the driving backboard and the light-emitting substrate is subjected to metal bonding, Form metal bonding layer；

The graphical light-emitting substrate and the metal bonding layer form pixel array；

Thin-film encapsulation layer is formed in the outside of the pixel array, the pixel array is completely covered in the thin-film encapsulation layer；

Pixel defining layer is formed at the top of the thin-film encapsulation layer, and forms quantum dot in the pixel defining layer, with shape At multicolor displaying.

2. the manufacturing method of display panel according to claim 1, it is characterised in that: the pixel array using yellow light and Etch process is formed.

3. the manufacturing method of display panel according to claim 1, it is characterised in that: the pixel defining layer uses yellow light Technique and etch process are formed.

4. the manufacturing method of display panel according to claim 1, it is characterised in that: formed in the pixel defining layer Black matrix" is also formed while quantum dot between quantum dot.

5. the manufacturing method of display panel according to claim 4, it is characterised in that: the quantum dot and the black square Battle array is formed using electrofluid printing technology.

6. a kind of display panel including driving backboard, the pixel array being arranged on the driving backboard and is arranged in the picture The outside of pixel array and the thin-film encapsulation layer that the pixel array is completely covered, it is characterised in that: the display panel further includes The quantum dot that pixel defining layer at the top of the thin-film encapsulation layer is set and is arranged in the pixel defining layer, to be formed Multicolor displaying.

7. display panel according to claim 6, it is characterised in that: the quantum dot includes red quantum dot and green amount Sub- point.

8. display panel according to claim 7, it is characterised in that: the display panel further comprises being arranged described Black matrix" in pixel defining layer and between the red quantum dot and green quantum dot.

9. display panel according to claim 6, it is characterised in that: the display panel further comprises being arranged described The insulating protective layer of the top side of quantum dot.

10. display panel according to claim 9, it is characterised in that: the display panel further comprises glass cover-plate, The glass cover-plate is encapsulated in the top of the insulating protective layer and the insulating protective layer is completely covered.