Quantum dot display panel, preparation method thereof and display device

Abstract

The invention provides a quantum dot display panel, a preparation method thereof and a display device.The preparation method of the quantum dot display panel comprises the steps that S1, a transparent substrate is spin-coated with photoetching liquid, multiple pixel pits are developed through photoetching after curing, and a pixel defining layer is formed; s2, transparent ink is printed in pixel pits of the pixel defining layer, and a concave lens shape is formed through ink climbing; printing quantum dot ink to fill the pixel pits; s3, the transparent substrate in the step S2 is inverted and attached to a blue light backlight plate, and the quantum dot display panel is formed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of display devices, and particularly relates to a quantum dot display panel, a preparation method thereof and a display device. BACKGROUND

[0002] Quantum dots, also known as semiconductor nanocrystals, have a particle size of 1-10 nm. Due to quantum size effect and dielectric confinement effect, quantum dots have unique photoluminescence (PL) and electroluminescence (EL) properties. Quantum dots have high quantum efficiency, high photochemical stability, are not prone to photolysis, have wide excitation, narrow emission, high color purity, and the emission color can be adjusted by controlling the size of quantum dots, and other excellent optical properties, and are widely used in light-emitting displays, photovoltaic devices, and biological fields.

[0003] Especially in the display field, quantum dots are combined with inkjet printing. As a non-contact patterning technology, inkjet printing can directly pattern ink droplets to a specified position on a substrate. Before inkjet printing film formation, a matrix distribution of pixel pits is usually formed by photolithography to form a pixel definition layer (PDL), and then quantum dot ink is printed into the pixel pits by inkjet printing to form patterned light emission. During the volatilization of the solvent of the ink and the drying process of the solute, the solute drying climbing effect will cause ink climbing phenomenon in the pixel pits, and the film formation uniformity is poor. Therefore, the prior art is committed to avoiding ink climbing.

[0004] However, with the diversification of different application scenarios, the light-emitting viewing angle requirement of the display device is also diversified. For example, in the application of display panels such as watches, notebooks, computers, and televisions, the light-emitting angle of the display panel needs to completely fit the scattering angle of the blue backlight. The scattering of the blue backlight has the characteristics of intermediate brightness and gradually darkening on the side, which is used for, for example, anti-peeping screens. However, the light emission of quantum dots has a disordered characteristic, that is, the light emission brightness to each angle is the same, which causes the scattering angle after excitation by the blue backlight to be fixed, and cannot completely fit the scattering angle of the blue backlight.

[0005] Therefore, the present application provides a quantum dot display panel, a preparation method thereof, and a display device. The light emitted by the quantum dot display panel can completely fit the scattering angle of the blue backlight, and the process is simple. SUMMARY

[0006] The purpose of the present application is to provide a quantum dot display panel, a preparation method thereof, and a display device. The light emitted by the quantum dot display panel can completely fit the scattering angle of the blue backlight, and the process is simple.

[0007] In a first aspect of the present application, a preparation method of a quantum dot display panel is provided, the preparation method comprising:

[0008] S1, spin-coating a photoetching solution on a transparent substrate, and forming a pixel defining layer by photoetching and developing a plurality of pixel pits after solidification;

[0009] S2, printing transparent ink in the pixel pits of the pixel defining layer, forming a concave lens shape by ink climbing, and then printing quantum dot ink to fill the pixel pits;

[0010] S3, inverting the transparent substrate of step S2 and attaching it to a blue backlight panel to form a quantum dot display panel.

[0011] In some embodiments, in step S1, the transparent substrate comprises at least one of glass, quartz, acrylic resin, polyimide, polyethylene terephthalate, polyvinyl alcohol, polyethylene naphthalate, or polydimethylsiloxane.

[0012] In some embodiments, the photoetching solution comprises monomers, a photoetching solvent, and a photoetching initiator.

[0013] In some embodiments, after the photoetching solution is solidified, photoetching exposure and developing treatment are performed to form pixel pits arranged in an array and obtain a pixel defining layer.

[0014] Further, the pixel pits are rectangular, and the depth of the pixel pits is 8-20um. Preferably, the depth of the pixel pits is 10-13um.

[0015] In some embodiments, the water droplet angle of the photoetching solution is 40°-100°, or the contact angle of the transparent ink on the glass surface is 10°-40°. Preferably, the water droplet angle of the photoetching solution is 60°-90°, or the contact angle of the transparent ink on the glass surface is 20°-30°.

[0016] In some embodiments, the printing thickness of the transparent ink is 10%-15% of the depth of the pixel pits.

[0017] In some embodiments, the transparent ink comprises polymerized monomers and an initiator.

[0018] Further, the polymerized monomers comprise at least one of acrylate monomers, epoxy monomers, or organosilicon monomers.

[0019] Further, the transparent ink further comprises a surface tension regulator.

[0020] In some embodiments, in the transparent ink, the mass fraction of the polymerized monomers is 80-96%, the mass fraction of the initiator is 2-8%, and the mass fraction of the surface tension regulator is 0-1%.

[0021] In some embodiments, the transparent ink has a viscosity of 2-30 mPa·s and a surface tension of 20-35 mN / m.

[0022] In some embodiments, after the transparent ink is printed into the pixel pits by the printer, the transparent ink is left to stand for 5-15 min and then cured by irradiation with a UV lamp.

[0023] In some embodiments, the quantum dot ink comprises quantum dots, a polymerization monomer, and an initiator.

[0024] The quantum dots comprise at least one of IIB-VIA quantum dots, IIIA-VA quantum dots, IVA-VIA quantum dots, IVA quantum dots, IB-IIIA-VIA quantum dots, IB-IIB-IVA-VIA quantum dots, VIII-VIA quantum dots, perovskite quantum dots, or carbon quantum dots (carbon dots).

[0025] In some embodiments, the quantum dot ink has a contact angle on a glass surface of 2-30°. Preferably, the quantum dot ink has a contact angle on a glass surface of 8-18°.

[0026] In some embodiments, in the quantum dot ink, the mass fraction of the quantum dots is 5-40%, the mass fraction of the polymerization monomer is 50-80%, the mass fraction of the initiator is 1-5%, and the mass fraction of the surface tension regulator is 0-1%.

[0027] In some embodiments, the quantum dot ink has a viscosity of 2-30 mPa·s and a surface tension of 20-35 mN / m.

[0028] In some embodiments, after the quantum dot ink is printed into the pixel pits by the printer, the quantum dot ink is cured by irradiation with a UV lamp.

[0029] In some embodiments, in step S3, the transparent substrate is inverted so that each pixel pit corresponds to a lamp bead on the blue light backlight plate one by one, and is fixed by lamination.

[0030] Further, after the transparent substrate is inverted and fixed with the blue light backlight plate, the quantum dot display panel comprises, from bottom to top, the blue light backlight plate, the pixel defining layer laminated on the upper surface of the blue light backlight plate, and the transparent substrate fixed on the upper surface of the pixel defining layer, the lower surface of the pixel defining layer having a plurality of pixel pits extending to the upper surface thereof, the pixel pits having, from bottom to top, the convex-lens-shaped quantum dot ink cured product and the transparent ink cured product arranged therein, the quantum dot ink cured product and the transparent ink cured product filling the pixel pits.

[0031] In a second aspect, the present application provides a quantum dot display panel obtained by the above preparation method.

[0032] In a third aspect of the present application, a quantum dot display panel is provided, which comprises, from bottom to top, a blue backlight plate, a pixel defining layer attached to the upper surface of the blue backlight plate, and a transparent substrate fixed to the upper surface of the pixel defining layer, wherein the lower surface of the pixel defining layer has a plurality of pixel pits extending to the upper surface thereof, and the pixel pits are filled with, from bottom to top, a convex-lens-shaped quantum dot ink solidification and a transparent ink solidification.

[0033] In some embodiments, the pixel pits correspond one-to-one to the lamp beads on the blue backlight plate, and the pixel pits are arranged in an array.

[0034] In some embodiments, the quantum dot ink solidification is formed by solidification of quantum dot ink, and the transparent ink solidification is formed by solidification of transparent ink.

[0035] In a fourth aspect of the present application, a display device is provided, which comprises the quantum dot display panel described above.

[0036] Compared with the prior art, the quantum dot display panel and the preparation method and the display device of the present application have at least the following advantages:

[0037] (1) In order to make the light emitted by the quantum dot display panel completely fit the scattering angle after excitation of the blue backlight, the transparent ink is first used to form a micro-concave lens shape by using the climbing characteristics of the ink, and then the quantum dot ink is used to fill the pixel pits. After the transparent substrate is inverted, the quantum dot ink forms a convex lens shape. It has been verified by experiments that the light emitted by the display device completely fits the scattering angle after excitation of the blue backlight. The transparent ink is added to form a better concave lens shape by climbing, which needs to satisfy that the water drop angle of the photoetching solution is between 40° and 100°, or the contact angle of the transparent ink on the glass surface is between 10° and 40°.

[0038] (2) It has been verified by experiments that the printing thickness of the transparent ink is between 10% and 15% of the depth of the pixel pit, and the light emitted by the display device can complete the fitting of the scattering angle after excitation of the blue backlight, otherwise the fitting degree will be reduced.

[0039] (3) The contact angle of the quantum dot ink on the glass surface is 2°-30°, which can make the quantum dot ink almost have no climbing phenomenon and overflow the pixel pit, and can fill the pixel pit evenly. BRIEF DESCRIPTION OF DRAWINGS

[0040] The following drawings are referred to in conjunction with the following detailed description of the application. Figure OneThese and other features of the present application will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are not to be considered limiting of its scope, the principles herein are described and explained with additional specificity and detail through the use of the accompanying drawings.

[0041] Figure 1 Normalized luminance diagram of the quantum dot display panel of Example 1 of the present application at different viewing angles.

[0042] Figure 2 Normalized luminance diagram of the quantum dot display panel of Example 2 of the present application at different viewing angles.

[0043] Figure 3 Normalized luminance diagram of the quantum dot display panel of Example 3 of the present application at different viewing angles.

[0044] Figure 4 Normalized luminance diagram of the quantum dot display panel of Comparative Example 1 of the present application at different viewing angles. DETAILED DESCRIPTION

[0045] The following examples are included to assist in understanding of the present application. The examples are not, and should not be interpreted to mean, that certain embodiments of the present application are preferred exemplifications intended to describe and enable the practice of the present application.

[0046] All terms in the specification, including technical and scientific terms, have meanings that are commonly used and understood by those of ordinary skill in the art unless otherwise defined. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0047] As used herein, the term "at least one", when preceding the enumeration of a plurality of elements, does not mean "one or more" but rather the entire list of elements is required. "Or" means "and / or". The terms "comprising", "including", "containing", etc., when used in the present specification, are meant to be interpreted inclusively rather than exclusively. The term "and / or" includes any and all combinations of one or more of the associated listed items. The term "plurality" means two or more. The term "connected" means directly or indirectly connected. The terms "first", "second", "third", etc., can be used herein to describe and distinguish various elements, components, regions, layers and / or sections, but the elements, components, regions, layers and / or sections should not be limited by these terms.

[0048] In a first aspect, the present application provides a preparation method of a quantum dot display panel, the preparation method comprising:

[0049] S1. spin-coating a photoresist on a transparent substrate, and after curing, forming a pixel defining layer by photoetching and developing a plurality of pixel pits;

[0050] S2. printing transparent ink in the pixel pits of the pixel defining layer, and forming a concave lens shape by ink climbing; and then printing quantum dot ink to fill the pixel pits;

[0051] S3. inverting the transparent substrate of step S2 and adhering it to a blue backlight panel to form a quantum dot display panel.

[0052] In some embodiments, in step S1, the transparent substrate comprises at least one of glass, quartz, acrylic resin (PMMA), polyimide (PI), polyethylene terephthalate (PET), polyvinyl alcohol (PVA), polyethylene naphthalate (PEN), or polydimethylsiloxane (PDMS). In addition to the listed transparent substrates, other transparent substrates commonly used in display panels are also within the scope of the present application.

[0053] In some embodiments, the photoresist comprises a monomer, a photoetching solvent, and a photoetching initiator.

[0054] The monomer includes at least one of (meth)acrylic acid, (meth)acrylic acid modified with a reactive monomer, SU-8 epoxy resin, acrylic ester containing unsaturated carbon-carbon double bond group, or epoxy modified acrylic ester, such as at least one of alicyclic (meth)acrylate, aromatic (meth)acrylate, dipentaerythritol acrylate, modified epoxy acrylate, multifunctional acrylate, or epoxy acrylate oligomer. In addition to the listed monomers, other monomers commonly used in the field of photoresist are also within the scope of the present application.

[0055] The photoresist solvent includes at least one of glycol ether, lactate, cellulose ether ester, ketone. The glycol ether includes at least one of propylene glycol methyl ether acetate, 2-methoxyethyl ether (diglyme), ethylene glycol monomethyl ether, or propylene glycol monomethyl ether; the lactate includes ethyl lactate or methyl lactate; the cellulose ether ester includes methyl cellulose acetate; the ketone includes methyl ethyl ketone or cyclohexanone. The initiator in the photoresist solution includes at least one of 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide (TPO), 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, methyl benzoylformate, 2,4-dihydroxybenzophenone, diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide, or 5-nitroacenaphthene. In addition to the listed solvents and initiators, other solvents and initiators commonly used in the field of photoresist are also within the scope of the present application.

[0056] In some embodiments, after the photoresist solution is cured, the photoresist is exposed to light and developed to form pixel pits in an array.

[0057] Further, the pixel pits are rectangular, and the depth of the pixel pits is 8-20 um, such as 8 um, 9 um, 10 um, 11 um, 12 um, 13 um, 14 um, 15 um, 16 um, 17 um, 18 um, 19 um, or 20 um, but is not limited to the listed values, and other unlisted values within the above range are also applicable. Preferably, the depth of the pixel pits is 10-13 um.

[0058] In some embodiments, the water droplet angle of the photoetching liquid is 40°-100°, for example, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, or 100°, but is not limited to the listed values, and other unlisted values within the above range are also applicable; or the contact angle of the transparent ink on the glass surface is 10°-40°, for example, 10°, 12°, 14°, 16°, 18°, 20°, 22°, 24°, 26°, 28°, 30°, 32°, 34°, 36°, 38°, or 40°, but is not limited to the listed values, and other unlisted values within the above range are also applicable. Preferably, the water droplet angle of the photoetching liquid is 60°-90°, or the contact angle of the transparent ink on the glass surface is 20°-30°.

[0059] In the prior art, the climbing phenomenon of the ink can cause the ink in the pixel pit to be uneven, the light emitted by the display device to be non-uniform, and the display device to not meet the requirement of uniform light emission; or in the field of electroluminescent display devices, the climbing phenomenon of the ink can also cause the ink to easily overflow the pixel pit and affect the conductive performance; therefore, the research in the prior art focuses on inhibiting or eliminating the climbing phenomenon of the ink. The display device of the present application has a blue backlight, the scattering angle after excitation of the blue light is bright in the middle and dark on both sides, the change in the scattering angle is similar to the shape of a convex lens, and the display device can be applied to an anti-peeping screen, etc. The light emitted by the quantum dots has a disordered characteristic, and if the structure of the existing photo-induced display device is used, the light emitted by the quantum dots cannot fit the scattering angle after excitation of the blue light.

[0060] In order to make the light emitted by the quantum dot display panel completely fit the scattering angle after excitation of the blue backlight, the transparent ink is used to form a micro-concave lens shape by using the climbing characteristic of the ink, and then the pixel pit is filled with quantum dot ink. After the transparent substrate is inverted, the quantum dot ink forms a convex lens shape, and experiments have verified that the light emitted by the display device completely fits the scattering angle after excitation of the blue backlight. The transparent ink is added to form a better concave lens shape by climbing, and the water droplet angle of the photoetching liquid needs to be between 40° and 100°, or the contact angle of the transparent ink on the glass surface needs to be between 10° and 40°.

[0061] In some embodiments, the printing thickness of the transparent ink is 10%-15% of the depth of the pixel pit, for example, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, or 15%, but is not limited to the listed values, and other unlisted values within the above range are also applicable. Experiments have verified that when the printing thickness of the transparent ink is between 10% and 15% of the depth of the pixel pit, the light emitted by the display device can completely fit the scattering angle after excitation of the blue backlight, otherwise the fitting degree will be reduced.

[0062] In some embodiments, the transparent ink includes: a polymerizable monomer, an initiator. The transparent ink does not contain quantum dots compared to quantum dot ink.

[0063] Further, the polymerizable monomer includes: at least one of an acrylate monomer, an epoxy monomer, or a silicone monomer.

[0064] The acrylate monomer includes: at least one of a mono-functional acrylate monomer, a di-functional acrylate monomer, a tri-functional acrylate monomer, and an oligomeric acrylate monomer. The mono-functional acrylate monomer includes: at least one of methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, lauryl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, dicyclopentyl (meth)acrylate (HDCPMA), cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate (AMA), 2-adamantyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, or stearyl (meth)acrylate. The di-functional acrylate monomer includes: at least one of tripropyleneglycol di(meth)acrylate, tetraethyleneglycol dimethacrylate, dimethacrylate, 1,12-dodecanediol di(meth)acrylate, 1,10-decanediol dimethacrylate, or 1,6-hexanediol diacrylate. The tri-functional acrylate monomer includes: at least one of (ethoxylated) trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, or dipentaerythritol tri(meth)acrylate and the like.

[0065] The acrylate monomer can further include an active polar group-containing acrylate monomer. The active polar group-containing acrylate monomer includes: at least one of 3-(acryloyloxy)-2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 2-acrylic acid-2-hydroxy-3-phenoxypropyl ester, 2-methyl-2-acrylic acid-2,3-dihydroxypropyl ester, 2-methyl-acryloyl ethoxy succinate, acrylamide, N-(3-dimethylaminopropyl) methacrylamide, 2-acrylic acid-2-[[(butylamino)-carbonyl]oxy]ethyl ester, or 2-(2-oxo-1-imidazolidinyl)ethyl methacrylate. In addition to the listed polymerizable monomers, other polymerizable monomers or oligomers commonly used in the field of printing inks are within the scope of the present application.

[0066] The initiator includes a photoinitiator and a thermal initiator. The photoinitiator includes at least one of 2,4,6-trimethylbenzoylphenyl phosphinate, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, methyl benzoylformate, 2,4-dihydroxybenzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, or 5-nitroacenaphalene. The thermal initiator includes at least one of benzoyl peroxide, lauryl peroxide, t-butyl peroxybenzoate, t-butyl peroxy-tert-amylate, azobisisobutyronitrile, or azobisisoheptane. In addition to the listed initiators, other initiators commonly used in the field of printing inks are also within the scope of the present application.

[0067] Further, the clear ink also includes a surface tension modifier. The surface tension modifier includes at least one of n-hexane, n-heptane, n-octane, nonane, decane, undecane, dodecane, methylpentane, dimethylbutane, bicyclohexane, methylhexane, methylheptane, dimethylhexane, methyloctane, methylnonane, 4-ethyloctane, 4-n-propylheptane, 3,3-diethylhexane, 2,4-dimethyl-3-isopropylpentane, 2-methyldecane, 4-propyloctane, 2-methyl-3-ethyloctane, 4-t-butylheptane, 4,4-diethylheptane, 2-methylundecane, 3-ethyldecane, 2,2-dimethyldecane, 4-propylnonane, 3,3-diethyloctane, cyclohexanone, cyclohexylmethylethyl ketone, cyclohexylpropanone, 4-ethylcyclohexanone, 1-propylcyclohexanone, 2-cyclohexylcyclohexanone, propylbicyclohexyl ketone, 4-ethylbicyclohexyl ketone, amylbicyclohexyl ketone, o-chlorophenylcyclopentyl ketone, cyclohexylphenyl methyl ketone, or hydroxycyclohexane phenone. In addition to the listed surface tension modifiers, other surface tension modifiers commonly used in the field of printing inks are also within the scope of the present application.

[0068] In some embodiments, in the transparent ink, the mass fraction of the polymerization monomer is 80-96% (for example, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, or 96%, but not limited to the listed values, and other unlisted values within the above range are also applicable), the mass fraction of the initiator is 2-8% (for example, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8%, but not limited to the listed values, and other unlisted values within the above range are also applicable), and the mass fraction of the surface tension regulator is 0-1% (for example, 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, but not limited to the listed values, and other unlisted values within the above range are also applicable).

[0069] In some embodiments, the viscosity of the transparent ink is 2-30 mPa s (for example, 2 mPa s, 4 mPa s, 6 mPa s, 8 mPa s, 10 mPa s, 12 mPa s, 14 mPa s, 16 mPa s, 18 mPa s, 20 mPa s, 22 mPa s, 24 mPa s, 26 mPa s, 28 mPa s, or 30 mPa s, but not limited to the listed values, and other unlisted values within the above range are also applicable), and the surface tension is 20-35 mN / m (20 mN / m, 21 mN / m, 22 mN / m, 23 mN / m, 24 mN / m, 25 mN / m, 26 mN / m, 27 mN / m, 28 mN / m, 29 mN / m, 30 mN / m, 31 mN / m, 32 mN / m, 33 mN / m, 34 mN / m, or 35 mN / m, but not limited to the listed values, and other unlisted values within the above range are also applicable). At this viscosity and surface tension, the inkjet is smooth and stable.

[0070] In some embodiments, after the transparent ink is printed into the pixel pits by the printer, it is left to stand for 5-15 min (for example, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, or 15 min, but not limited to the listed values, and other unlisted values within the above range are also applicable), and then cured by irradiation with a UV lamp. After the transparent ink is printed, it is left to stand for 5-15 min to complete the climbing of the transparent ink, and then cured by irradiation with a UV lamp.

[0071] In some embodiments, the quantum dot ink comprises: quantum dots, a polymerization monomer, an initiator.

[0072] Furthermore, the quantum dots include at least one of the following: group IIB-VIA quantum dots, group IIIA-VA quantum dots, group IVA-VIA quantum dots, group IVA quantum dots, group IB-IIIA-VIA quantum dots, group IB-IIB-IVA-VIA quantum dots, group VIII-VIA quantum dots, perovskite quantum dots, or carbon quantum dots (carbon dots). Each quantum dot comprises a core, a shell coating the core, and ligands modified on the surface of the shell. The band width of the shell material is greater than that of the core, and the shell protects the core. The ligands enable the quantum dots to be oil-soluble or water-soluble. Except for carbon dots, which are inherently hydrophilic, other quantum dots are typically directly synthesized as oil-soluble quantum dots (with organic acid, organic amine, organic phosphine, or thiol groups on their surface), and only through additional ligand modification can water-soluble quantum dots be formed. For example, the nuclei of group IIB-VIA quantum dots include: CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe or combinations thereof. For example, the cores of group IIIA-VA quantum dots include: GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, InZnP, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or combinations thereof. For example, the IVA-VIA family of quantum dot nuclei include: SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe or combinations thereof.For example, Group IVA quantum dot cores include: Si, Ge, SiC, SiGe, or combinations thereof. For example, Group IB-IIIA-VIA quantum dot cores include: CuInSe2, CuInS2, CuInGaSe, CuInGaS, or combinations thereof. For example, Group IB-IIB-IVA-VIA quantum dot cores include: CuZnSnSe, CuZnSnS, or combinations thereof. For example, perovskite quantum dots have a general structure of one of ABX3, A2B2X6, A3B3X9, where A is a monovalent amine-based organic cation, a monovalent inorganic metal cation (such as CH3NH3 + , NH2CHNH2+, C(NH2)3 + , Cs + , Li + , Na + , K + , Rb + , aryl groups, etc.), B is a divalent inorganic metal cation (such as divalent cations of rare earth metals, divalent cations of alkaline earth metals, divalent cations of transition metals, divalent cations of post-transition metals, etc.), and X is a monovalent anion (such as halogens, etc.). For example, the carbon quantum dots are nanomaterials with a size between 2-10 nm, mainly composed of carbon elements, which emit fluorescence after being excited by light of a specific wavelength, synthesized using carbon sources such as organic acids under microwave or high-temperature heating conditions, and usually contain oxygen, hydrogen, nitrogen, etc., with a rich surface of carboxyl, hydroxyl, etc., groups, and have hydrophilicity and good biocompatibility.

[0073] In some embodiments, the quantum dot ink has a contact angle on a glass surface of 2°-30°, such as 2°, 4°, 6°, 8°, 10°, 12°, 14°, 16°, 18°, 20°, 22°, 24°, 26°, 28°, or 30°, but is not limited to the listed values, and other unlisted values within the range are also applicable. Preferably, the quantum dot ink has a contact angle on a glass surface of 8°-18°. At this contact angle, the quantum dot ink can fill the pixel pit without spilling over the pixel pit, and can fill the pixel pit evenly.

[0074] In some embodiments, in the quantum dot ink, the mass fraction of quantum dots is 5-40% (for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%, but not limited to the listed values, and other unlisted values within the above range are also applicable), the mass fraction of polymerizable monomers is 50-80% (for example, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, but not limited to the listed values, and other unlisted values within the above range are also applicable), the mass fraction of initiator is 1-5% (for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, but not limited to the listed values, and other unlisted values within the above range are also applicable), and the mass fraction of surface tension regulator is 0-1% (for example, 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, but not limited to the listed values, and other unlisted values within the above range are also applicable).

[0075] In some embodiments, the viscosity of the quantum dot ink is 2-30 mPa s (for example, 2 mPa s, 4 mPa s, 6 mPa s, 8 mPa s, 10 mPa s, 12 mPa s, 14 mPa s, 16 mPa s, 18 mPa s, 20 mPa s, 22 mPa s, 24 mPa s, 26 mPa s, 28 mPa s, or 30 mPa s, but not limited to the listed values, and other unlisted values within the above range are also applicable), and the surface tension is 20-35 mN / m (20 mN / m, 21 mN / m, 22 mN / m, 23 mN / m, 24 mN / m, 25 mN / m, 26 mN / m, 27 mN / m, 28 mN / m, 29 mN / m, 30 mN / m, 31 mN / m, 32 mN / m, 33 mN / m, 34 mN / m, or 35 mN / m, but not limited to the listed values, and other unlisted values within the above range are also applicable). At the viscosity and surface tension, the inkjet is smooth and stable.

[0076] In some embodiments, after the quantum dot ink is printed into the pixel pits by the printer, it is irradiated and cured by a UV lamp. After the quantum dot ink is printed, it is immediately irradiated and cured by a UV lamp, which further avoids the climbing of the quantum dot ink and makes the surface of the cured quantum dot ink flat.

[0077] In some embodiments, in step S3, the transparent substrate is inverted so that each pixel pit corresponds to a lamp bead on the blue backlight plate one by one and is fixed by lamination.

[0078] Further, the transparent substrate is inverted and fixed with the blue backlight panel, and the quantum dot display panel comprises, from bottom to top, the blue backlight panel, the pixel defining layer attached to the upper surface of the blue backlight panel, and the transparent substrate fixed to the upper surface of the pixel defining layer. The lower surface of the pixel defining layer has a plurality of pixel pits extending to the upper surface thereof. The pixel pit comprises, from bottom to top, the convex-lens-shaped quantum dot ink solidification and the transparent ink solidification, and the quantum dot ink solidification and the transparent ink solidification fill the pixel pit.

[0079] In a second aspect, the present application provides a quantum dot display panel obtained by the above preparation method.

[0080] In a third aspect, the present application provides a quantum dot display panel comprising, from bottom to top, a blue backlight panel, a pixel defining layer attached to the upper surface of the blue backlight panel, and a transparent substrate fixed to the upper surface of the pixel defining layer. The lower surface of the pixel defining layer has a plurality of pixel pits extending to the upper surface thereof. The pixel pit comprises, from bottom to top, the convex-lens-shaped quantum dot ink solidification and the transparent ink solidification, and the quantum dot ink solidification and the transparent ink solidification fill the pixel pit.

[0081] In some embodiments, the pixel pit corresponds to a lamp bead on the blue backlight panel one-to-one, and the pixel pits are arranged in an array.

[0082] In some embodiments, the quantum dot ink solidification is obtained by curing quantum dot ink, and the transparent ink solidification is obtained by curing transparent ink.

[0083] In a fourth aspect, the present application provides a display device comprising the above quantum dot display panel.

[0084] The present application will be further described in detail below in combination with specific examples and comparative examples, but the present application is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different specific requirements, and the conditions not mentioned are conventional conditions in the industry.

[0085] Preparation of photoetching solution: 5 ml of PGMEA (propylene glycol methyl ether acetate) solution was taken, 2 g of aromatic monoacrylate, 3 g of dipentaerythritol acrylate, and 200 mg of TPO (2,4,6-trimethylbenzoyl-diphenyl phosphine oxide) were added, and the mixture was stirred uniformly at 40°C in the dark to obtain the photoetching solution, which was ready for use. The water drop angle of the photoetching solution was 90°.

[0086] Preparation of transparent ink: 4wt% of photoinitiator TPO (2,4,6-trimethylbenzoyl-diphenyl phosphine oxide), 50wt% of isobornyl methacrylate, 30wt% of 1,6-hexanediol diacrylate and 16wt% of 1,12-dodecanediol ester were mixed uniformly to obtain the transparent ink, which was ready for use. The viscosity of the transparent ink was 10 mPa·s, the surface tension was 32 mN / m, and the contact angle of the transparent ink on the glass surface was 25°.

[0087] Preparation of quantum dot ink: 20wt% of red quantum dots (CdSe / ZnSeS / ZnS), 3wt% of photoinitiator TPO (2,4,6-trimethylbenzoyl-diphenyl phosphine oxide), 38wt% of dicyclopentyl methacrylate, 35wt% of tripropyleneglycol diacrylate and 4wt% of ethoxylated trimethylolpropane triacrylate were mixed uniformly to obtain the quantum dot ink, which was ready for use. The viscosity of the quantum dot ink was 18 mPa·s, the surface tension was 28 mN / m, and the contact angle of the quantum dot ink on the glass surface was 15°.

[0088] Example 1:

[0089] A blank glass substrate with an area of 20cm*20cm was prepared, and the above-mentioned photoresist was spin-coated, baked at 90°C for 2min, exposed for 30s using a 365nm light source photolithography machine, then developed using a 0.0045% concentration KOH aqueous solution, and baked at 100°C for 30min to form an array of pixel pits with a depth of 12um, thereby obtaining a pixel defining layer.

[0090] The above-mentioned transparent ink was printed into the pixel pits using a printer, with a printing thickness of 0.5um, and then left to stand for 10min before being cured using a UV365nm lamp (intensity 3000 mj / cm 2 The above-mentioned quantum dot ink was printed into the pixel pits using a printer, with a printing thickness of 11.5um, and then immediately cured using a UV365nm lamp (intensity 4000 mj / cm 2

[0091] The glass substrate was inverted so that each pixel pit corresponded to a lamp bead on the blue backlight panel, and was fixed to obtain a quantum dot display panel. The luminance of the quantum dot display panel at different viewing angles was tested using a spectral analyzer PR670, and the normalized luminance at different viewing angles was obtained as shown in Figure 1

[0092] Example 2:

[0093] ​​A blank glass substrate with an area of 20 cm*20 cm was prepared, the above-mentioned photoresist was spin-coated, baked at 90°C for 2 min, exposed for 30 s using a 365 nm light source photoetching machine, then developed with a 0.0045% KOH aqueous solution, and baked at 100°C for 30 min to form pixel pits in an array distribution, the depth of the pixel pits was 12 um, and a pixel definition layer was obtained.

[0094] The above-mentioned transparent ink was printed into the pixel pits using a printer, the printing thickness was 1 um, and the sample was left to stand for 10 min, then cured by irradiation with a UV 365 nm lamp (intensity 3000 mj / cm 2 , irradiation time 60 s). The above-mentioned quantum dot ink was printed into the pixel pits using a printer, the printing thickness was 11 um, and then immediately cured by irradiation with a UV 365 nm lamp (intensity 4000 mj / cm 2 , irradiation time 60 s).

[0095] The glass substrate was inverted so that each pixel pit corresponded to a lamp bead on the blue backlight panel one by one, and was fixed to obtain a quantum dot display panel. The luminance of the quantum dot display panel at different viewing angles was tested by a spectrum analyzer PR670, the normalized luminance was obtained, and the normalized luminance at different viewing angles is shown in Figure 2 .

[0096] Example 3:

[0097] A blank glass substrate with an area of 20 cm*20 cm was prepared, the above-mentioned photoresist was spin-coated, baked at 90°C for 2 min, exposed for 30 s using a 365 nm light source photoetching machine, then developed with a 0.0045% KOH aqueous solution, and baked at 100°C for 30 min to form pixel pits in an array distribution, the depth of the pixel pits was 12 um, and a pixel definition layer was obtained.

[0098] The above-mentioned transparent ink was printed into the pixel pits using a printer, the printing thickness was 1.5 um, and the sample was left to stand for 10 min, then cured by irradiation with a UV 365 nm lamp (intensity 3000 mj / cm 2 , irradiation time 60 s). The above-mentioned quantum dot ink was printed into the pixel pits using a printer, the printing thickness was 10.5 um, and then immediately cured by irradiation with a UV 365 nm lamp (intensity 4000 mj / cm 2 , irradiation time 60 s).

[0099] The glass substrate was inverted so that each pixel pit corresponded to a lamp bead on the blue backlight panel one by one, and was fixed to obtain a quantum dot display panel. The luminance of the quantum dot display panel at different viewing angles was tested by a spectrum analyzer PR670, the normalized luminance was obtained, and the normalized luminance at different viewing angles is shown in Figure 3 .

[0100] Comparative Example 1:

[0101] A blank glass substrate with an area of 20cm*20cm was prepared, and the above-mentioned photoresist was spin-coated thereon, and baked at 90°C for 2min, and then exposed to light for 30s using a 365nm light source photolithography machine, and then developed using a 0.0045% KOH aqueous solution, and baked at 100°C for 30min to form pixel pits in an array distribution, with a depth of 12um, thereby obtaining a pixel definition layer.

[0102] The above-mentioned quantum dot ink was printed into the pixel pits using a printer, with a printing thickness of 12um, and then immediately cured by irradiation with a UV365nm lamp (intensity 4000 mj / cm 2 , for 60s).

[0103] The glass substrate was inverted so that each pixel pit corresponded to a lamp bead on the blue backlight panel, and was fixed to obtain a quantum dot display panel. The luminance of the quantum dot display panel at different viewing angles was tested by a spectrum analyzer PR670, and the normalized luminance at different viewing angles was obtained as shown in Figure 4 .

[0104] As can be seen from Figure 4 , the luminance of the quantum dot display panel of the prior art at different viewing angles is basically the same, and cannot fit the scattering angle after excitation by the blue backlight. However, Figures 1 to 3 , the luminance of the quantum dot display panel at different angles is more and more fitted to the scattering angle after excitation by the blue backlight; among them, Example 3 (i.e. Figure 3 ), on the basis of meeting the water drop angle of the photoresist and the contact angle of the transparent ink on the glass surface, the printing thickness of the transparent ink is between 10%-15% of the depth of the pixel pit, and the light emitted by the quantum dot display panel is completely fitted to the scattering angle after excitation by the blue backlight.

[0105] Although several aspects and embodiments have been disclosed in the present application, other aspects and embodiments will be apparent to those skilled in the art, and several modifications and improvements can be made without departing from the concept of the present application, which all fall within the scope of protection of the present application. The aspects and embodiments disclosed in the present application are only used for illustration, and are not intended to limit the present application, and the actual protection scope of the present application is subject to the claims.

Claims

1. A method for fabricating a quantum dot display panel, characterized in that, The preparation method includes: S1, spin-coating photoresist onto a transparent substrate, curing it, and then photolithography and development to form multiple pixel pits to form a pixel defining layer; S2, print transparent ink in the pixel pits of the pixel boundary layer, and use the ink to climb to form a concave lens shape; then print quantum dot ink to fill the pixel pits. S3, the transparent substrate from step S2 is inverted and attached to the blue backlight panel to form a quantum dot display panel.

2. The method for preparing a quantum dot display panel as described in claim 1, characterized in that, In step S1, one or more features selected from the group consisting of: (1) The transparent substrate includes at least one of glass, quartz, acrylic resin, polyimide, polyethylene terephthalate, polyvinyl alcohol, polyethylene naphthalate, or polydimethylsiloxane; (2) The photolithography solution includes: monomer, photolithography solvent and photolithography initiator; (3) After the photolithography solution is cured, photolithography exposure and development are performed to form pixel pits distributed in an array, thereby obtaining a pixel boundary layer; (4) The pixel pit is rectangular and the depth of the pixel pit is 8-20um.

3. The method for preparing a quantum dot display panel as described in claim 1, characterized in that, The water droplet angle of the photolithography solution is 40°-100°, or the contact angle of the transparent ink on the glass surface is 10°-40°.

4. The method for preparing a quantum dot display panel as described in claim 1, characterized in that, The printing thickness of the transparent ink is 10%-15% of the pixel pit depth.

5. The method for preparing a quantum dot display panel as described in claim 1, characterized in that, Includes one or more features selected from the following group: (1) The transparent ink includes: a polymer monomer and an initiator; the transparent ink also includes a surface tension modifier; (2) In the transparent ink, the mass fraction of the polymer monomer is 80-96%, the mass fraction of the initiator is 2-8%, and the mass fraction of the surface tension modifier is 0-1%. (3) The viscosity of the transparent ink is 2-30 mPa·s and the surface tension is 20-35 mN / m; (4) After the transparent ink is printed into the pixel pit by the printer, let it stand for 5-15 minutes, and then cure it with ultraviolet light.

6. The method for preparing a quantum dot display panel as described in claim 1, characterized in that, Includes one or more features selected from the following group: (1) The quantum dot ink comprises: quantum dots, polymer monomers, and initiators; (2) The contact angle of the quantum dot ink on the glass surface is 2°-30°; (3) In the quantum dot ink, the mass fraction of quantum dots is 5-40%, the mass fraction of polymer monomers is 50-80%, the mass fraction of initiator is 1-5%, and the mass fraction of surface tension modifier is 0-1%. (4) The viscosity of the quantum dot ink is 2-30 mPa·s and the surface tension is 20-35 mN / m; (5) Quantum dot ink is printed into the pixel pit by a printer and then cured by ultraviolet light.

7. The method for preparing a quantum dot display panel as described in claim 1, characterized in that, In step S3, the transparent substrate is inverted so that each pixel pit corresponds to one of the LED beads on the blue backlight board and is then bonded and fixed.

8. A quantum dot display panel, the quantum dot display panel comprising, from bottom to top: A blue backlight panel, a pixel defining layer attached to the upper surface of the blue backlight panel, and a transparent substrate fixed to the upper surface of the pixel defining layer, characterized in that the lower surface of the pixel defining layer has a plurality of pixel pits extending to its upper surface, and the pixel pits are provided with, from bottom to top: a convex lens-shaped quantum dot ink curing material and a transparent ink curing material, wherein the quantum dot ink curing material and the transparent ink curing material fill the pixel pits.

9. The quantum dot display panel as described in claim 8, characterized in that, The pixel pits correspond one-to-one with the LED beads on the blue backlight panel, and the pixel pits are distributed in an array; the quantum dot ink curing material is formed by curing quantum dot ink, and the transparent ink curing material is formed by curing transparent ink.

10. A display device comprising a quantum dot display panel obtained by any one of the preparation methods described in claims 1-7, or comprising a quantum dot display panel as described in any one of claims 8-9.

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