Manufacturing method of quantum rod light-emitting plate

Abstract

The invention relates to a manufacturing method of a quantum rod light-emitting plate, which comprises the following steps of: S1, coating an orientation layer on one surface of a transparent substrate, and applying directional friction to the orientation layer to enable the orientation layer to form horizontal orientation in a first axial direction; s2, mixing the quantum rod with a curable liquid crystal to form a coating liquid; s3, the coating liquid is coated on the orientation layer through a patterning method to form salient points, the surfaces of the salient points are in an arc shape, liquid crystal molecules of the curable liquid crystal are arranged in the first axial direction under the driving of the orientation layer, and the liquid crystal molecules of the curable liquid crystal are arranged in a variable inclination angle along the surface under the action of the arc-shaped surface, the quantum rods are oriented under the driving of the liquid crystal molecules, so that the liquid crystal molecules and the quantum rods are arranged along the first axial direction with variable inclination angles; and S4, curing the coating liquid, and fixing the orientation of the quantum rod liquid crystal molecules to obtain the quantum rod light-emitting plate. According to the invention, the quantum rod light-emitting plate with very high orientation degree can be manufactured, so that the quantum rod light-emitting plate can effectively emit polarized light.

Description

Technical Field

[0001] The invention relates to the technical field of displays, and in particular to a method for manufacturing a quantum rod light-emitting panel. Background Art

[0002] As an advanced nano-luminescent material, quantum rods have unique luminescent properties and application prospects. Among them, an important characteristic of quantum rods is the ability to produce polarized light. Polarized light refers to the vibration of light waves (electric vectors) in a specific direction. This characteristic makes quantum rods have broad application potential in the display field. In the device, in order for quantum rods to effectively generate polarized light, the quantum rods must be arranged on the plate in a consistent direction to form a quantum rod light-emitting plate. This is because only when the quantum rods are arranged in an orderly manner can the light waves they emit be polarized in a specific direction, thereby achieving a polarization effect. This requirement is crucial for the application of quantum rods in devices such as displays and polarizers.

[0003] The existing method for manufacturing quantum rod light-emitting panels generally involves pre-making quantum rods in a polymer film, and then directional stretching the quantum rods to orient them in the stretching direction. However, this manufacturing method does not have a high degree of orientation for the arrangement of quantum rods, and the polarization degree of the light emitted by the quantum rod light-emitting panel is also not high, which makes it difficult to meet its application in the display field.

[0004] At present, some people have proposed to use oriented liquid crystals to orient quantum rods in order to improve the orientation of quantum rods. However, the inclination of liquid crystal molecules in oriented liquid crystals is uniform, which will cause the quantum rods to be arranged with a single inclination after orientation. The angle of polarized light emitted by them is very small, which affects their application in display devices. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for manufacturing a quantum rod light-emitting panel, which can produce a quantum rod light-emitting panel with a very high degree of orientation, so that it can effectively emit polarized light, and the emission angle of the polarized light is relatively wide. The technical solution adopted is as follows: A method for manufacturing a quantum rod light-emitting panel, characterized by comprising the following steps: S1, coating an alignment layer on a surface of a transparent substrate, and applying directional friction to the alignment layer so that the alignment layer forms a horizontal alignment in a first axial direction; S2, mixing the quantum rods and the curable liquid crystal to form a coating liquid; S3, coating the coating liquid on the alignment layer by a patterning method to form convex points, based on the surface effect of the coating liquid, the surface of the convex points is arc-shaped, the liquid crystal molecules of the curable liquid crystal in the coating liquid are driven by the alignment layer to be arranged along the first axis, and under the action of the arc-shaped surface, they are shown as a variable tilt angle along the surface, and the quantum rods are oriented under the drive of the liquid crystal molecules, so that the liquid crystal molecules and the quantum rods are both arranged along the first axis with a variable tilt angle; S4, solidifying the coating liquid to fix the orientation of the quantum rods and liquid crystal molecules, thereby obtaining the quantum rod light-emitting plate.

[0006] In the manufacturing method provided by the present invention, in step S1, directional friction is applied to the orientation layer so that the orientation layer forms a horizontal orientation on the first axis (such as 0°), which can more effectively improve the polarization degree of light; in step S2, the quantum rods can be pre-dispersed in the curable liquid crystal to form a coating liquid; in step S3, the coating liquid is coated on the orientation layer by a patterning method to form convex points, based on the surface effect of the coating liquid, the surface of the convex point is arc-shaped, and the liquid crystal molecules of the curable liquid crystal in the coating liquid are driven by the orientation layer to be arranged along the first axis, and under the action of the arc-shaped surface, they are shown as a variable tilt angle along the surface, and the quantum rods are oriented under the drive of the liquid crystal molecules, so that the liquid crystal molecules and the quantum rods are both arranged along the first axis with a variable tilt angle, and a very high orientation degree can be obtained; in step S4, the coating liquid is solidified, and the orientation of the liquid crystal molecules and the quantum rods can be fixed, and finally a quantum rod light-emitting plate with a very high orientation degree can be obtained, thereby enabling it to effectively emit polarized light, and the emission angle of the polarized light is relatively wide.

[0007] Generally, the transparent substrate is a transparent plastic substrate or a glass substrate. As a preferred embodiment of the present invention, the transparent substrate is a glass substrate. Specifically, the transparent substrate can be a glass substrate with a thickness of 0.3 to 3 mm. It has good transparency and mechanical strength.

[0008] As a preferred embodiment of the present invention, the alignment layer in step S1 is a polyimide coating. The polyimide coating can be formed by coating a polyimide solution on the alignment layer and then curing it. Specifically, the alignment layer can be a polyimide coating with a thickness of no more than 500 nm.

[0009] As a preferred solution of the present invention, in step S1, the method of applying directional friction to the alignment layer is: directional friction is performed on the surface of the transparent substrate by a roller with flannel cloth to form a plurality of directional grooves along the first axial direction; in step S3, these directional grooves can make the liquid crystal molecules parallelly arranged along the first axial direction, so as to obtain a consistent orientation. Specifically, a glass substrate coated with a polyimide coating is subjected to directional friction treatment at a rubbing speed of 30 m / s and a rubbing number of 5 times to form the directional grooves.

[0010] As a preferred solution of the present invention, the pre-tilt angle of the alignment layer in step S1 is less than 3°, thereby further ensuring the horizontal arrangement of the quantum rods and avoiding the quantum rods from being tilted, resulting in different polarization degrees of light emitted at different angles.

[0011] As a preferred embodiment of the present invention, in step S2, ultrasonic waves are applied to the coating liquid to uniformly disperse the quantum rods in the curable liquid crystal.

[0012] As a preferred embodiment of the present invention, in step S2, the curable liquid crystal is a photopolymerizable liquid crystal; or, the curable liquid crystal is a mixture of photopolymerizable liquid crystal and nematic liquid crystal; in step S4, ultraviolet light is irradiated to photocure the monomer molecules of the photopolymerizable liquid crystal.

[0013] Generally, the monomer molecules of the photopolymerized liquid crystal have mesogen groups and photopolymerization functional groups, and also exhibit thermotropic liquid crystal properties before polymerization, such as nematic liquid crystal phase at 40-100°C. Among them, the mesogen groups can be cyclic structures such as biphenyl, phenylbenzoate, phenylcyclohexane, azobenzene, azomethine, azophenyl, phenylpyrimidine, diphenylethynyl, diphenylbenzoate, dicyclohexyl, cyclohexylphenyl, and terphenyl. The ends of these cyclic units can also have substituents such as cyano, alkyl, alkoxy, and halogen groups. The photopolymerization functional group can be (meth)acryloyl, epoxy, vinyl ether, etc., preferably (meth)acryloyl. In order to allow the liquid crystal to present a better cross-linked structure after polymerization, it is preferred that the monomer molecules of the photopolymerized liquid crystal have more than two photopolymerization functional groups.

[0014] For example, the monomer of the photopolymerizable liquid crystal may be a compound represented by the following general formula (IV):

[0015] wherein R is a hydrogen atom or a methyl group, A and D are each independently 1,4-phenylene or 1,4-cyclohexylene, B is 1,4-phenylene, 1,4-cyclohexylene, 4,4'-biphenylene or 4,4'-bicyclohexylene, Y and Z are each independently -COO-, -OCO- or -O-, and g and h are each independently an integer of 2 to 6.

[0016] When the curable liquid crystal is a photopolymerizable liquid crystal, in step S4, ultraviolet light is irradiated to photocure (polymerize and / or crosslink) the liquid crystal monomer; by ultraviolet light irradiation, the photopolymerizable functional groups of the liquid crystal monomer react to form a solid polymer, and the quantum rod is fixed in the solid polymer, and its orientation no longer changes. Specifically, ultraviolet light with a light intensity of 100mW / cm² can be used for irradiation for 30 seconds to cause the liquid crystal monomer to undergo a photocuring reaction to form a solid polymer, thereby fixing the quantum rod.

[0017] Typically, the quantum rod is in the shape of a rod, and its cross section can be circular, elliptical or polygonal, etc. In terms of the size of the quantum rod, both the length and diameter of the quantum rod can be controlled at the nanoscale, and the length is usually greater than the Bohr radius of the exciton. In terms of the structure of the quantum rod, the quantum rod is mainly composed of a core and a shell. The core is composed of a semiconductor material (such as ZnS or CdSe, etc.), and the shell is often coated with materials such as CdS. In terms of the material selection of the quantum rod, the quantum rod uses a semiconductor material that can emit visible light. By adjusting the composition and proportion of the material, light emission of different wavelengths can be achieved.

[0018] As a preferred embodiment of the present invention, in step S2, the quantum rods include red light quantum rods, green light quantum rods and blue light quantum rods. Red light quantum rods, green light quantum rods and blue light quantum rods are quantum rods with red, green and blue light luminescence colors. Thus, the quantum rod light-emitting plate can emit polarized light of blue, green and red to synthesize white polarized light. Among them, the quantum rod with blue light luminescence color needs to be excited by higher frequency blue light or ultraviolet light.

[0019] Usually, quantum rods of different luminescent colors have different sizes. Generally speaking, the diameter of blue light quantum rods ranges from 2 to 6 nanometers and the length ranges from 15 to 30 nanometers; the diameter of green light quantum rods ranges from 4 to 8 nanometers and the length ranges from 20 to 45 nanometers; the diameter of red light quantum rods ranges from 5 to 10 nanometers and the length ranges from 25 to 45 nanometers. For example: quantum rods with CdSe / ZnS cores are selected with a diameter of 5nm and a length of 20nm. Quantum rods of three luminescent colors, red, green and blue, are prepared to meet the needs of full-color display.

[0020] As a further preferred embodiment of the present invention, the red light quantum rods, green light quantum rods and blue light quantum rods are mixed with the curable liquid crystal in a ratio of R:G:B=1:2:0.5 to form a coating liquid. Generally, the mass ratio of quantum rods to curable liquid crystal is 1:10.

[0021] As a preferred solution of the present invention, the surface of the quantum rod used in step S2 is modified by a modifying material, thereby improving the dispersibility and stability of the quantum rod in the curable liquid crystal.

[0022] As a further preferred embodiment of the present invention, the modification material on the surface of the quantum rod is polyethylene glycol (PEG).

[0023] In the step S3, the coating liquid can be arranged on the orientation layer according to the convex dot pattern by various methods such as dispensing and coating. Generally, in order to save materials and obtain more precise patterns, it can be arranged by patterning methods (such as screen printing, printing and other printing methods), for example: a dot matrix can be formed on the substrate instead of coating the entire surface. For example: by screen printing, the coating liquid is arranged on the orientation layer in the form of a dot matrix, the dot matrix diameter is 50μm, and the spacing is 100μm. Then, the substrate is heated to 70°C (higher than the liquid crystal phase transition temperature), kept for 10 minutes to align the liquid crystal molecules, and then cooled to room temperature.

[0024] As a preferred solution of the present invention, in step S3, the coating liquid is entirely coated on the surface of the transparent substrate. Specifically, the coating thickness is 50-300 μm, which can be achieved by slit coating, scraping, spraying and other methods.

[0025] As another preferred embodiment of the present invention, in step S3, the coating liquid is coated on the surface of the transparent substrate by printing. Generally, the thickness of the printed coating liquid droplets is 50-100 μm, which can be achieved by screen printing, printing, pad printing, relief printing, gravure printing and other methods.

[0026] Generally, in step S3, the transparent substrate is first heated to a temperature above the liquid crystal phase transition temperature to align the liquid crystal molecules, and then cooled to a temperature below the glass transition temperature, so that the liquid crystal orientation is formed according to the friction curve of step S1. In the above process, the interaction between the liquid crystal molecules and the surface of the quantum rods will cause the quantum rods to be oriented according to the orientation of the liquid crystal molecules, so that the quantum rods are also oriented according to the oriented friction direction of step S1.

[0027] As a preferred solution of the present invention, in step S3, acoustic wave vibration is also applied to the transparent substrate, so that the quantum rods are oriented under the interference of the acoustic wave and driven by the liquid crystal.

[0028] As a further preferred embodiment of the present invention, the vibration direction of the acoustic wave is perpendicular to the orientation of the orientation layer, thereby more effectively improving the orientation of the quantum rods.

[0029] Compared with the prior art, the present invention has the following advantages: In the manufacturing method provided by the present invention, in step S1, directional friction is applied to the orientation layer to make the orientation layer form a horizontal orientation in the first axial direction (such as 0°), which can more effectively improve the polarization degree of light. The pre-tilt angle of the orientation layer is set to be less than 3°, which can further ensure the horizontal arrangement of the quantum rods and avoid the quantum rods from being tilted, resulting in different polarization degrees of light emitted at different angles. In step S2, the quantum rods can be pre-dispersed in the curable liquid crystal, and the quantum rods can be uniformly dispersed in the curable liquid crystal by ultrasound. In step S3, the coating liquid is coated on the orientation layer by a patterning method to form convex points, and the surface of the coating liquid is subjected to the patterning method. The surface of the convex point is in the shape of an arc, and the liquid crystal molecules of the curable liquid crystal in the coating liquid are arranged along the first axis under the drive of the orientation layer, and show a variable tilt angle along the surface under the action of the arc-shaped surface, and the quantum rods are oriented under the drive of the liquid crystal molecules, so that the liquid crystal molecules and the quantum rods are arranged along the first axis with a variable tilt angle, and a very high degree of orientation can be obtained; step S4 solidifies the coating liquid, which can fix the orientation of the liquid crystal molecules and the quantum rods, and finally a quantum rod light-emitting plate with a very high degree of orientation can be obtained, thereby enabling it to effectively emit polarized light, and the emission angle of the polarized light is wider. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of a quantum rod light-emitting panel produced by the production method provided in the preferred embodiment of the present invention.

[0031] Figure 2 yes Figure 1 The optical principle diagram of the quantum rod light-emitting panel shown is under the excitation of an excitation light source. DETAILED DESCRIPTION

[0032] like Figure 1-Figure 2 As shown, the method for making the quantum rod light-emitting panel comprises the following steps: S1, coating an alignment layer 2 on one surface of a transparent substrate 1, and applying directional friction to the alignment layer 2, so that the alignment layer 2 forms a horizontal alignment in a first axial direction 10; S2, mixing the quantum rod 3 and the curable liquid crystal 4 to form a coating liquid 5; S3, coating the coating liquid 5 on the alignment layer 2 by a patterning method to form convex points, based on the surface effect of the coating liquid 5, the surface of the convex points is arc-shaped, the liquid crystal molecules of the curable liquid crystal 4 in the coating liquid 5 are driven by the alignment layer 2 to be arranged along the first axis 10, and under the effect of the arc-shaped surface, they are inclined at a variable angle along the surface, and the quantum rods 3 are oriented under the drive of the liquid crystal molecules, so that the liquid crystal molecules and the quantum rods 3 are arranged along the first axis 10 with a variable inclination angle θ; S4, solidifying the coating liquid 5 to fix the orientation of the quantum rods 3 and the liquid crystal molecules, thereby obtaining a quantum rod light-emitting plate.

[0033] In this embodiment, the transparent substrate 1 in step S1 is a glass substrate with a thickness of 1 mm, which has good transparency and mechanical strength.

[0034] In this embodiment, the alignment layer 2 in step S1 is a polyimide coating with a thickness of 200 nm. The polyimide coating is formed by spin coating a polyimide solution on a glass substrate to form a uniform coating, and then subjected to a directional rubbing treatment with a rubbing direction of 0°.

[0035] In this embodiment, in step S1, a roller with flannel is used to perform directional rubbing on the surface of the transparent substrate 1 to form a plurality of directional grooves along the first axial direction 10; in step S3, these directional grooves can make the liquid crystal molecules parallelly arranged along the first axial direction 10, thereby obtaining a consistent orientation. Specifically, a glass substrate coated with a polyimide coating is subjected to directional rubbing treatment at a rubbing speed of 30 m / s and rubbing times of 5 times to form directional grooves.

[0036] In this embodiment, the pre-tilt angle of the alignment layer 2 in step S1 is less than 3°, thereby further ensuring the horizontal arrangement of the quantum rods 3 and avoiding the quantum rods 3 from being tilted, resulting in different polarization degrees of light emitted at different angles.

[0037] In this embodiment, the quantum rods 3 in step S2 include red light quantum rods, green light quantum rods and blue light quantum rods, which are mixed with curable liquid crystal 4 in a ratio of R:G:B=1:2:0.5 to form a coating liquid 5; ultrasonic waves are applied to the coating liquid 5 to uniformly disperse the quantum rods 3 in the curable liquid crystal 4. The mass ratio of the quantum rods 3 to the liquid crystal is 1:10. The quantum rod light-emitting plate can emit polarized light of blue, green and red to synthesize white polarized light. The quantum rods 3 with a blue light emission color need to be excited by a higher frequency of blue light or ultraviolet light.

[0038] In this embodiment, the quantum rod 3 in step S2 is mainly composed of a core and a shell. The core is composed of a semiconductor material (such as ZnS or CdSe, etc.), and the shell is usually coated with a material such as CdSe. It is in a rod shape with a diameter of 5nm and a length of 20nm. The quantum rods 3 of three luminous colors, red, green and blue, are prepared to meet the needs of full-color display. The surface of the quantum rod 3 is modified by polyethylene glycol (PEG), thereby improving the dispersibility and stability of the quantum rod 3 in the curable liquid crystal 4.

[0039] In this embodiment, the curable liquid crystal 4 in step S2 is a photopolymerized liquid crystal, the monomer molecules of which have biphenyl mesogenic groups and (meth) acryloyl photopolymerization functional groups, and the monomer molecules of which contain two photopolymerization functional groups. The photopolymerized liquid crystal exhibits a nematic liquid crystal phase at 60°C. In step S4, ultraviolet light is irradiated to photocure (polymerize and / or crosslink) the liquid crystal monomer; ultraviolet light with a light intensity of 100mW / cm² is used for irradiation for 30 seconds, and the photopolymerization functional groups of the liquid crystal monomer react to form a solid polymer, while the quantum rod 3 is fixed in the solid polymer, and its orientation no longer changes.

[0040] For example, the monomer of the photopolymerizable liquid crystal has a compound represented by the following general formula (IV):

[0041] wherein R is a hydrogen atom or a methyl group, A and D are each independently 1,4-phenylene or 1,4-cyclohexylene, B is 1,4-phenylene, 1,4-cyclohexylene, 4,4'-biphenylene or 4,4'-bicyclohexylene, Y and Z are each independently -COO-, -OCO- or -O-, and g and h are each independently an integer of 2 to 6.

[0042] In this embodiment, in step S3, the coating liquid 5 is placed on the alignment layer 2 in the form of a dot matrix by screen printing, with a dot matrix diameter of 50 μm and a pitch of 100 μm. Then, the substrate is heated to 70°C (higher than the phase transition temperature of the liquid crystal), maintained for 10 minutes to align the liquid crystal molecules, and then cooled to room temperature.

[0043] In this embodiment, in step S3, the transparent substrate 1 is first heated to a temperature above the liquid crystal phase transition temperature to orient the liquid crystal molecules, and then cooled to a temperature below the glass transition temperature, so that the liquid crystal orientation is formed according to the friction curve of step S1. In the above process, the interaction between the liquid crystal molecules and the surface of the quantum rods 3 causes the quantum rods 3 to be oriented according to the orientation of the liquid crystal molecules, so that the quantum rods 3 are also oriented according to the oriented friction direction of step S1. The transparent substrate 1 can also be subjected to acoustic vibration, and the vibration direction of the acoustic wave is perpendicular to the orientation of the orientation layer 2, so that the quantum rods 3 are oriented under the interference of the acoustic wave and driven by the liquid crystal.

[0044] In addition, it should be noted that the names of the various parts of the specific embodiments described in this specification may be different, and any equivalent or simple changes made based on the structure, features and principles of the patent concept of the present invention are included in the protection scope of the patent of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for making a quantum rod light-emitting panel, characterized in that The steps include: S1, coating an alignment layer on a surface of a transparent substrate, and applying directional friction to the alignment layer so that the alignment layer forms a horizontal alignment in a first axial direction; S2, mixing the quantum rods and the curable liquid crystal to form a coating liquid; S3, coating the coating liquid on the alignment layer by a patterning method to form convex points, based on the surface effect of the coating liquid, the surface of the convex points is arc-shaped, the liquid crystal molecules of the curable liquid crystal in the coating liquid are driven by the alignment layer to be arranged along the first axis, and under the action of the arc-shaped surface, they are shown as a variable tilt angle along the surface, and the quantum rods are oriented under the drive of the liquid crystal molecules, so that the liquid crystal molecules and the quantum rods are both arranged along the first axis with a variable tilt angle; S4, solidifying the coating liquid to fix the orientation of the quantum rods and liquid crystal molecules, thereby obtaining the quantum rod light-emitting plate.

2. The method for making a quantum rod light-emitting panel according to claim 1, characterized in that: In the step S1, the alignment layer is a polyimide coating.

3. The method for making a quantum rod light-emitting panel according to claim 1, characterized in that: In the step S1, the method of applying directional friction to the orientation layer is: directional friction is performed on the surface of the transparent substrate by a roller with flannel cloth to form a plurality of directional grooves along the first axis; in the step S3, these directional grooves can make the liquid crystal molecules arranged in parallel along the first axis, thereby obtaining a consistent orientation.

4. The method for making a quantum rod light-emitting panel according to claim 1, characterized in that: In the step S2, ultrasonic waves are applied to the coating liquid to uniformly disperse the quantum rods in the curable liquid crystal.

5. The method for making a quantum rod light-emitting panel according to claim 1, characterized in that: The curable liquid crystal is a photopolymerizable liquid crystal, and the monomer molecules of the photopolymerizable liquid crystal have a mesogen group and a photopolymerizable functional group; In the step S4, ultraviolet light is irradiated to photo-cure the monomer molecules of the photopolymerizable liquid crystal.

6. The method for manufacturing a quantum rod light-emitting panel according to claim 1, characterized in that: The curable liquid crystal is a mixture of photopolymerizable liquid crystal and nematic liquid crystal.

7. The method for making a quantum rod light-emitting panel according to claim 1, characterized in that: In the step S2, the quantum rods include red light quantum rods, green light quantum rods and blue light quantum rods.

8. The method for manufacturing a quantum rod light-emitting panel according to claim 1, characterized in that: The surface of the quantum rod used in step S2 is modified by a modification material.

9. The method for manufacturing a quantum rod light-emitting panel according to claim 1, characterized in that: In the step S3, the coating liquid is entirely coated on the surface of the transparent substrate.

10. The method for manufacturing a quantum rod light-emitting panel according to claim 1, characterized in that: In the step S3, the coating liquid is disposed on the alignment layer in a dot matrix form.

11. The method for manufacturing a quantum rod light-emitting panel according to claim 1, characterized in that: In the step S3, acoustic wave vibration is also applied to the transparent substrate, so that the quantum rods are disturbed by the acoustic wave and driven by the liquid crystal to be oriented.

12. The method for manufacturing a quantum rod light-emitting panel according to claim 11, characterized in that: The vibration direction of the acoustic wave is perpendicular to the orientation of the alignment layer.

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