Patterned QLED micro display device and preparation method thereof

Abstract

The invention relates to a patterned QLED micro display device and a preparation method thereof. The patterned QLED micro display device comprises a driving circuit substrate; the patterned pixel unit is arranged above the driving circuit substrate in a deposition and plasma etching mode, and the patterned pixel unit comprises a quantum dot light-emitting unit; the insulating glue layer is filled between every two adjacent patterned pixel units, and the insulating glue layer is further arranged on the outer side of the patterned pixel units on the periphery of the device; and the transparent electrode is arranged above the patterned pixel units and the insulating glue layer in a deposition mode. According to the invention, problems of quantum dot performance reduction and low pixel density during quantum dot layer patterning processing can be solved; and the preparation method of the patterned QLED micro display device can be compatible with the existing semiconductor process, and is simple and easy to operate.

Description

Technical Field

[0001] The present disclosure relates to the field of optoelectronic display technology, and in particular to a patterned QLED micro-display device and a preparation method thereof. Background Art

[0002] The development of display technology has brought people a better human-computer interaction experience. With the progress of the times, people are pursuing more extreme display effects. Among them, ultra-small micro-display technology has developed rapidly and has been widely used in near-eye display scenarios such as virtual / augmented reality (VR / AR). At present, micro-display technology based on Micro-LED and Micro-OLED has gradually been commercialized. Micro-LED technology is based on traditional inorganic III-V semiconductors, which have high brightness and good stability, and are suitable for the preparation of high-brightness micro-displays; however, the processing of preparing Micro-LED requires more complex semiconductor processing technology, which is costly and limits its large-scale application. Micro-OLED technology is an organic light-emitting diode driven by silicon. It combines planar OLED with CMOS circuit drive to achieve micron-level pixel control. OLED is limited by the properties of the material itself and cannot achieve very high brightness. In addition, the life of OLED devices at higher brightness is low, which cannot meet application scenarios with high brightness requirements.

[0003] Quantum dot light-emitting diode (QLED) is a new type of electroluminescent device that uses charge injection to activate quantum dots to emit light. It has the characteristics of wide color gamut, high brightness, solution processing, and low cost, which can meet the application needs of display. The method of constructing a Micro-QLED micro-display system is relatively simple, with lower cost, more compact structure, and higher overall efficiency.

[0004] In the existing technology, the Micro-QLED micro-display system has high requirements for patterning technology. In the process flow, the performance of the previous functional layer should be minimized during processing, which brings challenges to the existing process. There are various quantum dot layer patterning methods, such as micro / nano-imprinting, inkjet printing, photolithography, etc. Among them, imprinting and inkjet printing technologies are difficult to achieve pixel units below 20 microns in large quantities, so the development of such processes is hindered; QLED photolithography technology has attracted a lot of attention due to its mature process and the ability to produce high pixel density.

[0005] In the QLED photolithography process, a hole injection layer, a hole transport layer, a patterned light-emitting layer, an electron transport layer, and a metal cathode are usually deposited in sequence on the ITO layer of a transparent conductive substrate. Among them, the quantum dot patterned light-emitting layer is formed by blending a cross-linkable semiconductor polymer containing a photosensitizer and quantum dots to form an ink, which is then spin-coated, exposed, and developed. However, for the Micro-QLED micro-display system prepared by this process, on the one hand, ligand exchange after quantum dot synthesis can easily lead to surface state defects in quantum dots, resulting in a decrease in light efficiency; on the other hand, the photolithography cross-linked polymer affects the charge injection ability of the quantum dot layer, thereby affecting the performance of the entire device. Summary of the invention

[0006] The present invention innovatively proposes a patterned QLED micro-display device and a preparation method thereof, applies plasma etching to the preparation of quantum dot display devices, etches to generate patterned pixel units, fills with insulating glue and then deposits transparent electrodes on the entire surface, which helps to solve problems such as quantum dot performance degradation and low pixel density during patterning of the quantum dot layer; and the adopted method for preparing the patterned QLED micro-display device is compatible with existing semiconductor processes, and the method is simple and easy to operate.

[0007] According to a first aspect of the present invention, a patterned QLED microdisplay device is provided, comprising: a driving circuit substrate; a patterned pixel unit, wherein the patterned pixel unit is arranged above the driving circuit substrate by deposition and plasma etching, wherein the patterned pixel unit comprises a quantum dot light-emitting unit; an insulating glue layer, wherein the insulating glue layer is filled between two adjacent patterned pixel units, and the insulating glue layer is also arranged on the outside of the patterned pixel unit at the periphery of the device; and a transparent electrode, wherein the transparent electrode is arranged above the patterned pixel unit and the insulating glue layer by deposition.

[0008] In some optional implementations, a patterned anode electrode is disposed at the center of the driving circuit substrate, and a frame-shaped cathode electrode is disposed at the periphery of the driving circuit substrate.

[0009] In some optional embodiments, the patterned QLED micro display device also includes: an outer transparent electrode, one end of the outer transparent electrode is connected to the transparent electrode, the other end of the outer transparent electrode is connected to any frame of the square cathode electrode, and there is a gap between the outer transparent electrode and the insulating glue layer adjacent to it.

[0010] In some optional embodiments, the patterned pixel unit further includes at least a hole injection unit, a hole transport unit and an electron transport unit.

[0011] According to a second aspect of the present invention, a method for preparing a patterned QLED microdisplay device is provided, comprising: depositing a functional layer on the entire surface above a driving circuit substrate by deposition, wherein the functional layer includes a quantum dot light-emitting layer; etching the functional layer by plasma etching based on a preset patterned photoresist mask and preset etching conditions; filling the grooves etched in the functional layer with insulating glue; and depositing a transparent electrode on the entire surface above the functional layer filled with the insulating glue by deposition.

[0012] In some optional embodiments, the method further includes: preparing a photoresist mask by spin coating, exposure, and development; hardening the photoresist mask based on preset hardening conditions to generate the preset patterned photoresist mask; wherein the preset hardening conditions at least include: a hardening temperature of 80 to 120° C. and a hardening time of 30 minutes.

[0013] In some optional embodiments, the etching conditions include at least: an etching temperature of 20 to 50°C, an etching power of 500 to 1000W, a RF power of 50 to 200W, and a chamber pressure of 2 to 8mTorr; the etching gas of the plasma etching is a mixed gas, and the mixed gas includes at least Ar2, Cl2 and CH4, or the mixed gas includes at least Ar2, Cl2 and BCl3.

[0014] In some optional embodiments, Ar2 accounts for the largest proportion in the etching gas, and Cl2 accounts for the smallest proportion.

[0015] In some optional embodiments, the entire surface of the functional layer deposited on the driving circuit substrate by deposition includes: depositing a hole injection layer, a hole transport layer, the quantum dot light-emitting layer and an electron transport layer in sequence from bottom to top on the driving circuit substrate by deposition; or, depositing an electron transport layer, the quantum dot light-emitting layer, a hole transport layer and a hole injection layer in sequence from bottom to top.

[0016] In some optional embodiments, the functional layer includes a first functional layer, and the entire surface of the functional layer deposited on the driving circuit substrate by deposition includes: depositing a hole injection layer, a hole transport layer and the quantum dot light-emitting layer in sequence from bottom to top on the driving circuit substrate by deposition to form the first functional layer.

[0017] In some optional embodiments, after etching the functional layer, the method further includes: depositing an electron transfer unit on the first functional layer by deposition; and filling the gaps between adjacent electron transfer units and the grooves etched in the first functional layer with insulating glue.

[0018] In some optional embodiments, the functional layer includes a second functional layer, and the entire surface of the functional layer deposited on the driving circuit substrate by deposition includes: depositing an electron transport layer, the quantum dot light-emitting layer and a hole transport layer in sequence from bottom to top on the driving circuit substrate by deposition to form the second functional layer.

[0019] In some optional embodiments, after etching the functional layer, the method further includes: depositing a hole injection unit on the second functional layer by deposition; and filling the gaps between adjacent hole injection units and the grooves etched in the second functional layer with insulating glue.

[0020] Compared with the prior art, one or more embodiments of the above scheme have at least the following advantages or beneficial effects: the present invention innovatively uses plasma etching in patterned QLED microdisplay devices and their preparation, etches the functional layer deposited on the entire surface to generate patterned pixel units, and then deposits a transparent electrode on the entire surface after filling with insulating glue, which helps to solve the problems of quantum dot performance degradation and low pixel density during patterning of the quantum dot layer; and the method for preparing the patterned QLED microdisplay device adopted is compatible with existing semiconductor processes, and the method is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure, but do not constitute a limitation of the present disclosure. It should be noted that for the sake of clarity, the components illustrated in the accompanying drawings are not necessarily drawn to scale.

[0022] Figure 1 is a schematic diagram of a patterned QLED micro display device according to an embodiment of the present invention.

[0023] Figure 2 is a partial cross-sectional schematic diagram of a patterned QLED micro-display device according to an embodiment of the present invention.

[0024] Figure 3 4 is a flow chart of a method for preparing a patterned QLED micro display device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that as long as there is no conflict, the various embodiments of the present invention and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present invention.

[0026] Meanwhile, in the following description, many specific details are set forth for the purpose of explanation to provide a thorough understanding of the embodiments of the present invention. However, it is apparent to those skilled in the art that the present invention may be implemented without using the specific details or the specific manner described herein.

[0027] The present invention innovatively proposes a patterned QLED micro-display device. Figure 1 is a schematic diagram of a patterned QLED micro display device according to an embodiment of the present invention. Figure 2 FIG. 1 is a partial cross-sectional schematic diagram of a patterned QLED micro-display device according to an embodiment of the present invention. Figure 1 and Figure 2 As shown, the patterned QLED micro display device may include: a driving circuit substrate 21; a patterned pixel unit, which is disposed on the driving circuit substrate 21 by deposition and plasma etching, wherein the patterned pixel unit includes a quantum dot light-emitting unit 24; an insulating glue layer 27, which is filled between two adjacent patterned pixel units, and the insulating glue layer 27 is also disposed on the outside of the patterned pixel unit at the periphery of the device; and a transparent electrode 28, which is disposed on the patterned pixel unit and the insulating glue layer 27 by deposition. In order to ensure that the transparent electrode can be connected to the driving circuit in the driving circuit substrate 21, the thickness of the transparent electrode 28 is greater than the thickness of the patterned pixel unit.

[0028] In the embodiment of the present invention, the patterned pixel unit at least further includes a hole injection unit HIL22 , a hole transport unit HTL23 and an electron transport unit 25 .

[0029] In an embodiment of the present invention, when preparing the above-mentioned patterned QLED micro-display device, a hole injection layer (HIL), a hole transport layer (HTL), a quantum dot light-emitting layer (QD layer) and an electron transport layer (ETL) can be deposited layer by layer on the driving circuit substrate 21 by a whole-surface deposition method. Afterwards, the corresponding hole injection unit HIL22, hole transport unit HTL23, quantum dot light-emitting unit 24 and electron transport unit 25 are obtained by etching using a plasma etching method (Inductively Coupled Plasma, ICP), which together constitute a patterned pixel unit, and the etched grooves are filled with insulating glue. At the same time, the outer side of the patterned pixel unit on the periphery of the device is also filled with insulating glue to form an insulating glue layer 27, so as to insulate each patterned pixel unit in the device, so that it is completely insulated and separated, and current crosstalk is prevented from causing light leakage in the patterned pixel unit, thereby ensuring the safe operation of the device. Finally, a transparent electrode 28 is deposited by a whole-surface deposition method to achieve common electrode connectivity.

[0030] For example, photoresist can be selected as the insulating glue, which can be positive photoresist and negative photoresist, including SU8 photoresist, polyimide photoresist (PI glue) and other photoresists that form insulating polymers after light curing.

[0031] In the embodiment of the present invention, a patterned anode electrode is disposed at the center of the driving circuit substrate 21 , and a frame-shaped cathode electrode is disposed at the periphery of the driving circuit substrate 21 .

[0032] For example, the driving circuit of the driving circuit substrate 21 may be a CMOS driving circuit. The transparent electrode 28 is used as a cathode and combined with the patterned anode electrode in the driving circuit substrate 21 to apply current to the patterned pixel unit to make it emit light, thereby realizing a patterned QLED micro display device.

[0033] In the embodiment of the present invention, in order to facilitate circuit design, the device also includes: an outer transparent electrode 29, one end of the outer transparent electrode 29 is connected to the transparent electrode 28, and the other end of the outer transparent electrode 29 is connected to any frame of the square cathode electrode. There may be a gap between the outer transparent electrode 29 and the insulating glue layer 27 adjacent thereto, wherein the size of the gap may be 0 to 50 microns.

[0034] It should be noted that the transparent electrode 28 and the outer transparent electrode 29 can be realized by deposition at the same time, and the two can be prepared as an integrated transparent electrode by deposition.

[0035] By providing the outer transparent electrode 29 , the transparent electrode 28 located above the patterned pixel unit can be connected to the frame-shaped cathode electrode of the driving circuit substrate 21 , so as to realize pixelated control of the patterned QLED micro display device.

[0036] It should be noted that in the embodiment of the present invention, in order to improve the stability of the working performance of the patterned QLED micro display device and ensure the light output effect, an intermediate electrode 26 can also be set between the electron transport unit 25 and the transparent electrode 28, that is, after the electron transport layer ETL is deposited, an intermediate electrode layer is deposited on the entire surface, and then ICP etching is performed.

[0037] The present invention also proposes a method for preparing a patterned QLED micro-display device. Figure 3 FIG. 1 is a flow chart of a method for preparing a patterned QLED micro display device according to an embodiment of the present invention. Figure 3 As shown, the method for preparing the patterned QLED micro display device may include:

[0038] S301: depositing a functional layer on the entire surface of the driving circuit substrate by deposition, wherein the functional layer includes a quantum dot light-emitting layer;

[0039] S302: etching the functional layer by plasma etching based on a preset patterned photoresist mask and preset etching conditions;

[0040] S303: Filling the grooves formed by etching in the functional layer with insulating glue;

[0041] S304: Depositing a transparent electrode on the entire surface of the functional layer filled with insulating glue by deposition.

[0042] In an embodiment of the present invention, a hole injection layer (HIL), a hole transport layer (HTL), a quantum dot light-emitting layer (QD layer) and an electron transport layer (ETL) are deposited layer by layer as functional layers by a whole-surface deposition method, wherein the material of the hole injection layer HIL may include poly (3,4-ethylenedioxythiophene) -polystyrene sulfonic acid (PEDOT:PSS), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN), copper phthalocyanine (CuPc), 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanoquinone-dimethane (F4-TCNQ), polythienothiophene (PTT) doped with poly (perfluoroethylene-perfluoroether sulfonic acid) (PFFSA), MoO 3. One or more of V2O5, WO3 or ReO3, etc.; the material of the hole transport layer HTL may include (9,9-dioctylfluorene-CO-N-(4-butylphenyl) diphenylamine) (TFB), polyvinylcarbazole (PVK), poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine) (poly-TPD), poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylenediamine) (PFB), 4,4',4"-tri(carbazole-9-yl)aniline (TCTA), 4,4'-bis(9-carbazole)biphenyl (CBP), N,N'-diphenyl-N,N'(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), etc. One or more.

[0043] The material of the quantum dot light-emitting layer QD can be selected from at least one of II-VIA group compounds, IV-VIA group compounds, and III-VA group compounds, including quantum dots such as CdTe, CdS, CdSe, CdSeS, ZnSe, InP, PbS, CuInS, ZnSe, ZnCdSe, CdZnSeS, and derivative structures coated with one or more layers of core-shell structure, including at least one of perovskite quantum dot materials, organic-inorganic perovskite quantum dots, and all-inorganic perovskite quantum dots.

[0044] In an embodiment of the present invention, during the plasma etching process, a preset patterned photoresist mask can be first obtained through spin coating, exposure, development, hardening and other processes. The photoresist of the mask can be positive photoresist S1813, positive photoresist SPR220i, positive photoresist AZ series including AZP4620 and cross-linkable semiconductor polymer photoresist, insulating photoresist, etc. The thickness of the mask can be 0.1 to 5 microns.

[0045] Afterwards, the front side of the driving circuit substrate with the functional layer deposited thereon is etched using plasma. Since the designed light-emitting area is protected by a preset patterned photoresist mask, the unprotected area will be etched away to form a plurality of patterned pixel units corresponding to the preset patterned photoresist mask, thereby realizing the patterning of the entire functional layer.

[0046] Finally, insulating glue is used to fill the grooves etched in the functional layer to achieve insulating isolation between the patterned pixel units, and the transparent electrode is deposited again using the whole-surface deposition method to complete the preparation of the patterned QLED microdisplay device, wherein the material of the transparent electrode can be one or more of glass / indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium zinc oxide (IZO), aluminum, silver, etc.

[0047] Embodiment 1:

[0048] Now, taking the preparation of a positive patterned QLED micro display device as an example, the preparation method in the embodiment of the present invention includes:

[0049] S311: Prepare a driving circuit substrate, wherein a patterned anode electrode is disposed at the center of the driving circuit substrate and a square-shaped cathode electrode is disposed at the periphery. The driving circuit substrate is sequentially placed in deionized water, acetone, and ethanol for ultrasonic treatment, and each ultrasonic treatment lasts for 10 minutes.

[0050] S312: On the driving circuit substrate, a functional layer is prepared by deposition. When preparing the functional layer, first, PEDOT:PSS is spin-coated on the entire surface as a hole injection layer, and dried at 130℃ / 20min, with a thickness of about 40nm. After drying, TFB is spin-coated on the entire surface as a hole transport layer, and dried at 130℃ / 20min, with a thickness of about 30nm. Secondly, red light CdSe quantum dot solution is spin-coated on the entire surface as a quantum dot light-emitting layer, and dried at 50℃ / 20min, with a thickness of 30nm. Then, ZnO solution is spin-coated on the entire surface as an electron transport layer, and baked at 100℃ for 10min; thickness 50nm. Finally, the ITO cathode layer is evaporated to form the first layer of transparent electrode with a thickness of 50nm, completing the preparation of the entire surface functional layer.

[0051] S313: using positive photoresist AZP4620 photolithography to prepare a photoresist etching mask, and developing the hard film to obtain a patterned preset patterned photoresist mask.

[0052] S314: Setting preset etching conditions, etching the functional layer by plasma etching ICP. The preset etching conditions may include: etching temperature of 25° C., etching power of 500 W, RF power of 100 W, and chamber pressure of 8 mTorr.

[0053] Through the attempts of relevant R&D personnel on ICP etching technology, when conventional ICP etching is applied to the embodiments of the present invention, although the corresponding device can be prepared, it will cause different degrees of damage to the various functional layers in the device after etching, especially the quantum dot light-emitting layer, affecting the overall light-emitting effect of the device. Through a large number of experimental analyses, the cause of such problems is that a large proportion of chemical etching occurs in the conventional ICP etching process, and the plasma generated in the etching process damages the functional layer (especially the QD layer).

[0054] Therefore, in order to reduce the damage of plasma to the QD layer, during etching, the etching gas that can be used can be a mixed gas of Ar2, Cl2 and CH4, so that Ar2 accounts for the largest proportion (preferably greater than 40%) and Cl2 accounts for the smallest proportion (preferably less than 20%). For example, the gas flow ratio of each gas is 5:1:2. For example, the gas flow rate of Ar2 is 50sccm, the gas flow rate of Cl2 is 10sccm, and the gas flow rate of CH4 is 20sccm. In order to reduce the impact of plasma on functional layers such as the QD layer during etching, by adjusting the proportion of ICP etching gas, Ar2 accounts for the largest proportion (preferably greater than 40%) and Cl2 accounts for the smallest proportion (preferably less than 20%), so that a large proportion of the ICP etching reaction is physical etching and a small proportion is chemical etching, thereby reducing the damage of plasma to the QD layer during chemical etching.

[0055] After etching, photoresist remains on the surface of the functional layer, and the residual amount is about 0.05 to 1 micron by measurement. Therefore, after the ICP etching is completed, the small amount of residual photoresist can be removed by washing with acetone.

[0056] S315: Using insulating glue, the grooves formed by etching in the functional layer are filled to completely insulate and separate the patterned pixel units, thereby preventing current crosstalk from causing light leakage in the patterned pixel units.

[0057] S316: Depositing an ITO cathode layer on the entire surface to form a second layer of transparent electrode, the thickness of which is 300 nm, to ensure that the entire surface common electrode of the device is connected to the frame-shaped cathode electrode on the drive circuit substrate.

[0058] Embodiment 2:

[0059] The preparation of an upright patterned QLED microdisplay device is now described as an example. The quantum dot solution in the above-mentioned embodiment 1 is replaced with a blue light CsPbBr3 quantum dot solution. The specific preparation process is similar to the process in the above-mentioned embodiment 1 and will not be repeated here.

[0060] Furthermore, when the functional layer is prepared by deposition, an intermediate electrode layer may be deposited after the electron transport layer is deposited to ensure the overall light output effect of the device.

[0061] In an embodiment of the present invention, in order to ensure the anti-etching effect of the preset patterned photoresist mask, the method further includes: preparing the photoresist mask by spin coating, exposure, and development; hardening the photoresist mask based on preset hardening conditions to generate a preset patterned photoresist mask; wherein the preset hardening conditions at least include: a hardening temperature of 80 to 120°C and a hardening time of 30 minutes. Among them, in order to reduce the impact of a small amount of residual photoresist on the functional layer and avoid damaging the functional layer due to solvent cleaning, the photoresist in this embodiment uses a cross-linkable semiconductor polymer photoresist, and the cross-linkable polymer is one of PFSO, TFB, PVK, and PFO. After the etching process is completed, there is no need to use solvent cleaning to remove the small amount of residual photoresist, and the S304 step can be directly performed to reduce the damage of strong solvents to functional layers such as QDs.

[0062] In the embodiment of the present invention, the etching conditions at least include: etching temperature of 20-50°C, etching power of 500-1000W, RF power of 50-200W, and chamber pressure of 2-8mTorr; the etching gas of plasma etching is a mixed gas, and the mixed gas includes at least Ar2, Cl2 and CH4, or the mixed gas includes at least Ar2, Cl2 and BCl3. Among them, the gas flow rate of Cl2 gas is 10-15sccm. CH4 and BCl3 play the role of passivating the side wall in the etching gas, and a suitable gas flow rate can be selected.

[0063] It should be noted that the gas flow ratio of Ar2, Cl2 and CH4 or BCl3 can be 5:1:2, or other applicable ratios.

[0064] In the embodiment of the present invention, the etching rate and the depth ratio can be improved by adjusting the appropriate ratio of etching power to radio frequency power, wherein the etching power is 800-1000W and the radio frequency power is 100-150W.

[0065] In an embodiment of the present invention, both an upright QLED micro display device and an inverted QLED micro display device can be prepared by the above-mentioned preparation method. Therefore, the functional layer is deposited on the entire surface above the driving circuit substrate by deposition, specifically including: depositing a hole injection layer, a hole transport layer, a quantum dot light-emitting layer and an electron transport layer in sequence from bottom to top above the driving circuit substrate by deposition; or, depositing an electron transport layer, a quantum dot light-emitting layer, a hole transport layer and a hole injection layer in sequence from bottom to top to form a functional layer.

[0066] Embodiment 3:

[0067] Now, taking the preparation of an inverted patterned QLED micro display device as an example, the preparation method in the embodiment of the present invention includes:

[0068] S331: Prepare a driving circuit substrate.

[0069] S332: On the driving circuit substrate, functional layers are prepared by deposition. First, the entire surface is spin-coated with ZnO solution as an electron transport layer and baked at 100°C for 10 minutes; secondly, the entire surface is spin-coated with green light CdSe quantum dot solution as a quantum dot light-emitting layer and dried at 50°C / 20 minutes; thirdly, vacuum evaporate NPB as a hole transport layer HTL with a thickness of 20nm; then, vacuum evaporate HAT-CN as a hole injection layer HIL with a thickness of 20nm; finally, vacuum evaporate ITO cathode layer to form the first layer of transparent electrode with a thickness of 40nm, completing the preparation of the entire surface inverted functional layer.

[0070] S333: Prepare a photoresist etching mask by using positive photoresist AZP4620 photolithography, and obtain a patterned preset patterned photoresist mask after developing the hard film.

[0071] S334: setting preset etching conditions, and etching the functional layer by ICP plasma etching.

[0072] S335: Using insulating glue, the grooves formed by etching in the functional layer are filled to completely insulate and separate the patterned pixel units, thereby preventing current crosstalk from causing light leakage in the patterned pixel units.

[0073] S336: Deposit an ITO cathode layer on the entire surface to form a second layer of transparent electrode. The thickness of this transparent electrode layer is 300 nm, ensuring that the entire common electrode of the device is connected to the frame-shaped cathode electrode on the drive circuit substrate.

[0074] In the embodiment of the present invention, the method further comprises: cleaning the etched functional layer.

[0075] It should be noted that if a semiconductor polymer photoresist is selected, there is no need to clean the functional layer after etching.

[0076] In the embodiment of the present invention, the functional layer can be prepared first and then ICP etching can be performed to form a patterned pixel unit; or part of the functional layer in the complete functional layer can be deposited first, and then the remaining functional layer can be deposited after ICP etching.

[0077] In an embodiment of the present invention, a functional layer is deposited on the entire surface above the driving circuit substrate by deposition, specifically including: depositing a hole injection layer, a hole transport layer and a quantum dot light-emitting layer in sequence from bottom to top above the driving circuit substrate by deposition to form a first functional layer.

[0078] In an embodiment of the present invention, after etching the functional layer, the method further includes: depositing an electron transport unit on the first functional layer by deposition; and filling the gaps between adjacent electron transport units and the grooves etched in the first functional layer with insulating glue.

[0079] Embodiment 4:

[0080] The preparation of an upright patterned QLED microdisplay device is now described as an example. Based on the above-mentioned Example 1, a hole injection layer, a hole transport layer, and a quantum dot light-emitting layer are sequentially deposited in S312 to form a first functional layer. Then, S313 is executed. After plasma etching ICP is completed, an electron transport unit and a first layer of transparent electrode are deposited. Then, S315 is executed to complete the subsequent process.

[0081] It should be noted that after the quantum dot light-emitting layer is deposited in S312, an intermediate electrode layer may be further deposited to ensure the overall light-emitting effect of the device.

[0082] When depositing the electron transport unit and the first layer of transparent electrode, a whole-surface deposition method may be adopted, and the specific process will not be described in detail.

[0083] In an embodiment of the present invention, when preparing an inverted patterned QLED microdisplay device, a partial functional layer can also be prepared first. The above-mentioned functional layer includes a second functional layer. The functional layer is deposited on the entire surface above the driving circuit substrate by deposition. Specifically, it includes: depositing an electron transport layer, a quantum dot light-emitting layer and a hole transport layer in sequence from bottom to top above the driving circuit substrate by deposition to form a second functional layer.

[0084] In the embodiment of the present invention, after etching the functional layer, the method further includes: depositing a hole injection unit on the second functional layer by deposition; and filling the gaps between adjacent hole injection units and the grooves etched in the second functional layer with insulating glue.

[0085] The present invention innovatively uses plasma etching in patterned QLED microdisplay devices and their preparation, etches the functional layer deposited on the entire surface to generate patterned pixel units, and then deposits transparent electrodes on the entire surface after filling with insulating glue, which helps to solve problems such as quantum dot performance degradation and low pixel density during patterning of the quantum dot layer; and the method for preparing the patterned QLED microdisplay device adopted is compatible with existing semiconductor processes, and the method is simple and easy to operate.

[0086] It should be understood that the embodiments disclosed in the present invention are not limited to the specific processing steps or materials disclosed herein, but should be extended to equivalent substitutions of these features understood by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0087] The "embodiment" mentioned in the specification means that the specific features or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrase "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0088] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A patterned QLED micro display device, comprising: Driving circuit substrate; A patterned pixel unit, which is disposed on the driving circuit substrate by deposition and plasma etching, wherein the patterned pixel unit includes a quantum dot light-emitting unit; An insulating glue layer, the insulating glue layer is filled between two adjacent patterned pixel units, and the insulating glue layer is also arranged on the outside of the patterned pixel units at the periphery of the device; A transparent electrode is disposed on the patterned pixel unit and the insulating glue layer by deposition.

2. The device according to claim 1, wherein A patterned anode electrode is arranged at the center of the driving circuit substrate, and a frame-shaped cathode electrode is arranged at the periphery of the driving circuit substrate.

3. The device according to claim 2, further comprising: An outer transparent electrode, one end of which is connected to the transparent electrode, and the other end of which is connected to any frame of the square-shaped cathode electrode, and a gap exists between the outer transparent electrode and the insulating glue layer adjacent thereto.

4. The device according to any one of claims 1 to 3, wherein The patterned pixel unit at least further comprises a hole injection unit, a hole transport unit and an electron transport unit.

5. A method for preparing a patterned QLED micro display device, comprising: Depositing a functional layer on the entire surface of the driving circuit substrate by deposition, wherein the functional layer includes a quantum dot light-emitting layer; Based on a preset patterned photoresist mask and preset etching conditions, etching the functional layer by plasma etching; Filling the grooves formed by etching in the functional layer with insulating glue; A transparent electrode is deposited on the entire surface of the functional layer filled with the insulating glue by deposition.

6. The method according to claim 5, further comprising: Prepare a photoresist mask by spin coating, exposure and development; Based on a preset hardening condition, the photoresist mask is hardened to generate the preset patterned photoresist mask, The preset hardening conditions at least include: a hardening temperature of 80-120° C. and a hardening time of 30 minutes.

7. The method according to claim 5, wherein: The etching conditions at least include: etching temperature of 20-50° C., etching power of 500-1000 W, RF power of 50-200 W, and chamber pressure of 2-8 mTorr; The etching gas of the plasma etching is a mixed gas, and the mixed gas at least includes Ar2, Cl2 and CH4, or the mixed gas at least includes Ar2, Cl2 and BCl3.

8. The method according to claim 7, wherein: Among the etching gases, Ar2 accounts for the largest proportion and Cl2 accounts for the smallest proportion.

9. The method according to any one of claims 5 to 8, wherein: The step of depositing the functional layer on the entire surface of the driving circuit substrate by deposition includes: By deposition, a hole injection layer, a hole transport layer, the quantum dot light emitting layer and an electron transport layer are sequentially deposited from bottom to top on the driving circuit substrate; or, The electron transport layer, the quantum dot light-emitting layer, the hole transport layer and the hole injection layer are deposited in sequence from bottom to top.

10. The method according to any one of claims 5 to 8, wherein: The functional layer includes a first functional layer, and the step of depositing the functional layer on the entire surface of the driving circuit substrate by deposition includes: By deposition, a hole injection layer, a hole transport layer and the quantum dot light-emitting layer are sequentially deposited from bottom to top on the driving circuit substrate to form the first functional layer.

11. The method according to claim 10, after etching the functional layer, further comprising: Depositing an electron transport unit on the first functional layer by deposition; The gaps between the adjacent electron transport units and the grooves etched in the first functional layer are filled with insulating glue.

12. The method according to any one of claims 5 to 8, wherein: The functional layer includes a second functional layer, and the step of depositing the functional layer on the entire surface of the driving circuit substrate by deposition includes: By deposition, an electron transport layer, the quantum dot light-emitting layer and a hole transport layer are sequentially deposited from bottom to top on the driving circuit substrate to form the second functional layer.

13. The method according to claim 12, after etching the functional layer, further comprising: Depositing a hole injection unit on the second functional layer by deposition; The gaps between the adjacent hole injection units and the grooves etched in the second functional layer are filled with insulating glue.

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