CN103412429B - A kind of preparation method of display panels - Google Patents

Abstract

The invention provides a method for preparing a liquid crystal display panel. The liquid crystal display panel includes two oppositely arranged substrates and a polymer-dispersed liquid crystal layer arranged between the two substrates. The two substrates face the polymer-dispersed liquid crystal layer. A transparent conductive layer is formed on one side of the layer, and the preparation method includes: forming a transparent conductive layer on two substrates respectively; carrying out cell alignment treatment on the two substrates to form a liquid crystal cell, and in the liquid crystal cell, the formation of the two substrates has The surfaces of the transparent conductive layer are opposite, and a mixture of prepolymer and liquid crystal is arranged between the two substrates; the two substrates are irradiated vertically with ultraviolet light beams, and the two substrates are irradiated by the transparent conductive layer Applying a voltage creates an electric field between the two substrates, and the prepolymer reacts to form a polymer, forming a polymer dispersed liquid crystal layer. The invention can solve the problem of slow response speed of liquid crystal molecules in the PDLC after voltage is applied to the liquid crystal display panel in the prior art.

Description

A kind of preparation method of liquid crystal display panel

technical field

The invention relates to the technical field of liquid crystal display, in particular to a preparation method of a liquid crystal display panel.

Background technique

Polymer Dispersed Liquid Crystal (PDLC, Polymer Dispersed Liquid Crystal) is a mixture of low molecular liquid crystal (liquid crystal, abbreviated as LC) and a prepolymer, and undergoes a polymerization reaction under certain conditions to form micron-sized liquid crystal droplets that are evenly dispersed In the polymer network, the dielectric anisotropy of liquid crystal molecules is used to obtain materials with electro-optic response characteristics, which can realize the bright state in the power-on state and the dark state in the power-off state.

Figure 1 is a schematic diagram of the distribution of the phases before the polymerization of the prepolymer and liquid crystal molecules in the prior art, the mixture 1 of the prepolymer and the liquid crystal molecules is located between the upper substrate 2 and the lower substrate 3, and the photoinitiator 4 is distributed between the prepolymer and the liquid crystal In the molecular mixture 1, the state of the two phases of the prepolymer and the liquid crystal molecules is a homogeneous state without phase separation.

In the prior art, PDLC generally uses photopolymerization to polymerize the prepolymer. FIG. 2 is a schematic diagram of the structure of PDLC in the prior art, which is prepared only by light irradiation. The upper substrate 2 is irradiated by ultraviolet light 5, and the polymer molecular chain In the system, it is in the shape of random coils, and the random coils wrap the liquid crystal molecules 7, and the interaction between the two is relatively large. The rigid molecules of the liquid crystal are distributed in the flexible medium, so that the interface between the two has a high degree of interaction. The energy limits the movement ability of liquid crystal molecules when changing states, resulting in slow response of PDLC.

In addition, in the prior art PDLC preparation process, the prepolymer is also polymerized by applying a voltage. As shown in FIG. 3, the voltage makes the liquid crystal molecules 7 vertically aligned, but at this time the prepolymer 6 forms a crosslinked network structure, The wrapping effect on the liquid crystal molecules 7 is still strong, and the response speed is still very slow. According to the above, how to convert the flexible package between the polymer and the liquid crystal molecules into a rigid contact will be the key to solving the response speed of liquid crystal molecules in PDLC.

Contents of the invention

The purpose of the technical solution of the present invention is to provide a method for preparing a liquid crystal display panel, which is used to solve the problem of slow response speed of liquid crystal molecules in PDLC after voltage is applied to the liquid crystal display panel in the prior art.

The invention provides a method for preparing a liquid crystal display panel, the liquid crystal display panel includes two oppositely arranged substrates, and a polymer dispersed liquid crystal layer arranged between the two substrates, the two substrates face the One side of the polymer dispersed liquid crystal layer is formed with a transparent conductive layer, wherein the preparation method comprises:

Forming transparent conductive layers on the two substrates respectively;

Carrying out cell alignment treatment on the two substrates to form a liquid crystal cell, in the liquid crystal cell, the surfaces of the two substrates on which the transparent conductive layer is formed face each other, and a pre-polymerization film is arranged between the two substrates. A mixture of substances and liquid crystals;

UV beams are used to irradiate the two substrates vertically, and a voltage is applied to the two substrates through the transparent conductive layer to form an electric field between the two substrates, and the prepolymer reacts to form a polymer, forming a polymer dispersion liquid crystal layer.

Preferably, in the above-mentioned preparation method, wherein the vertically irradiating the two substrates with an ultraviolet beam comprises:

Through the mask plate with a plurality of microholes arranged in an array, the ultraviolet light forms a plurality of ultraviolet light beams for vertically irradiating the two substrates.

Preferably, in the above-mentioned preparation method, the diameter of the ultraviolet light beam is on the order of microns.

Preferably, in the above-mentioned preparation method, the diameter of the ultraviolet light beam is 0.01 μm to 10 μm.

Preferably, in the above-mentioned preparation method, the diameter of the ultraviolet light beam is 0.1 micron to 1 micron.

Preferably, in the above-mentioned preparation method, the irradiation intensity of the ultraviolet light beam is 5 mW/cm2 to 10 mW/cm2.

Preferably, in the above-mentioned preparation method, the voltage applied to the two substrates is 30 volts to 40 volts.

Preferably, the above-mentioned preparation method, wherein, the prepolymer is an acrylate material or an epoxy resin material, and the weight percentage of the prepolymer in the mixture is 30% to forty percent.

Preferably, in the preparation method described above, a photoinitiator is also added to the mixture of the prepolymer and the liquid crystal, wherein the weight percentage of the photoinitiator in the mixture is % One to three percent.

Preferably, the above-mentioned preparation method, wherein, the photoinitiator is selected from one or more of hydroxycyclohexyl phenyl ketone, 2-hydroxyl-2-methyl-1-phenyl-1-propanone kind.

The technical scheme of the present invention has the following beneficial effects:

The preparation method adopts two control methods of simultaneously applying voltage and ultraviolet beam irradiation to realize the polymerization of the prepolymer. Optimally, the prepolymer and the liquid crystal molecules are irradiated by forming multiple micron-level ultraviolet beams. The mixed system makes ordered orientation polymerization occur in the mixed system, and the polymer fiber network structure is formed in the system. The liquid crystal molecules are oriented parallel to the fiber surface due to the law of the lowest energy, so the fiber network structure in the direction perpendicular to the two substrates will be Reduce the resistance of the liquid crystal molecules moving in the direction perpendicular to the two substrates. When the voltage is applied, the driving force required for the liquid crystal molecules to turn to the direction perpendicular to the two substrates is reduced, the speed of movement is accelerated, and the response time is reduced.

Description of drawings

Figure 1 shows a schematic diagram of the distribution of the phases before the polymerization of the prepolymer and the liquid crystal molecules;

Fig. 2 shows the schematic diagram of the distribution of each phase prepared by only light irradiation when PDLC is polymerized in the prior art;

Fig. 3 shows the schematic diagram of the distribution of each phase when the prior art adopts pressure control to polymerize PDLC;

Fig. 4 represents the application structure schematic diagram of the preparation method described in the specific embodiment of the present invention;

Figure 5 shows a schematic diagram of the distribution of the phases of the prepolymer and liquid crystal molecules in a pressurized state;

Fig. 6 is a schematic diagram showing the orientation trend of liquid crystal molecules on the surface of polymer fibers.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The preparation method of the liquid crystal display panel provided by the specific embodiment of the present invention, the liquid crystal display panel includes two substrates arranged oppositely, and a polymer dispersed liquid crystal layer arranged between the two substrates, and the two substrates face One side of the polymer dispersed liquid crystal layer is formed with a transparent conductive layer, wherein the preparation method comprises:

Forming transparent conductive layers on the two substrates respectively;

Carrying out cell alignment treatment on the two substrates to form a liquid crystal cell, in the liquid crystal cell, the surfaces of the two substrates on which the transparent conductive layer is formed face each other, and a pre-polymerization film is arranged between the two substrates. A mixture of substances and liquid crystals;

UV beams are used to irradiate the two substrates vertically, and a voltage is applied to the two substrates through the transparent conductive layer to form an electric field between the two substrates, and the prepolymer reacts to form a polymer, forming a polymer dispersion liquid crystal layer.

The preparation method of the liquid crystal display panel described in the specific embodiment of the present invention adopts the method of simultaneously applying voltage and ultraviolet beam irradiation to realize the polymerization of the prepolymer, and under the joint action of the ultraviolet beam and the applied voltage, the prepolymerization The material forms a cross-linked network structure, and the driving force required for the liquid crystal molecules to be aligned perpendicular to the direction of the two substrates is reduced, so that the response speed of the liquid crystal molecules in the PDLC of the liquid crystal display panel is accelerated.

Optimally, a mask plate with a plurality of microholes arranged in an array is used, so that the ultraviolet light forms a plurality of ultraviolet beams for vertically irradiating the two substrates.

Preferably, the diameter of the ultraviolet light beam is on the order of microns.

By forming multiple micron-level ultraviolet beams to irradiate the mixed system of the prepolymer and the liquid crystal molecules, orderly orientation polymerization occurs in the mixed system, and at the same time, an electric field perpendicular to the two substrates is applied to the polymerization system to make the polymerization reaction Orientation polymerization in the vertical state of the liquid crystal, the synergistic effect of the two forms a polymer network fiber network structure, and the liquid crystal molecules tend to be arranged in parallel on the surface of this structure, so the resistance of the liquid crystal to the direction perpendicular to the two substrates is reduced, and the response speed is fast, thus solving the problem. The problem of slow response speed of PDLC in the prior art.

Fig. 4 is a schematic diagram of the application structure of the preparation method described in a specific embodiment of the present invention. The purpose of the preparation method is to form a polymer dispersed liquid crystal layer between two substrates to form a liquid crystal display panel. In conjunction with Figure 4, the preparation method mainly includes the following steps:

Forming transparent conductive layers on the first substrate 10 and the second substrate 11 respectively;

Specifically, various methods such as deposition, coating, and sputtering can be used to form transparent conductive layers on the first substrate 10 and the second substrate 11 respectively. The two substrates, that is, the first substrate 10 and the second substrate 11 can be made of transparent materials such as glass, quartz, resin, etc., and are not limited here; the material of the transparent conductive layer can be selected from indium tin oxide ( Indium TinOxide, ITO), indium zinc oxide (Indium Zin Oxide, IZO), indium gallium zinc oxide (Indium Gallium ZincOxide, IGZO) and other transparent materials.

The first substrate 10 and the second substrate 11 are subjected to box-to-box processing, and the conductive layer on the first substrate 10 and the second substrate 11 is opposite, and a prepolymer is arranged between the first substrate 10 and the second substrate 11 A mixture of 6 and liquid crystal molecules 7;

Specifically, optionally, the two substrates can be arranged to form a liquid crystal cell first, so that the surfaces of the two substrates formed with the transparent conductive layer are opposite, and then the mixture of the prepolymer and the liquid crystal is injected into the liquid crystal cell ; It is also possible to drop the mixture of prepolymer and liquid crystal on the surface of one of the substrates where the transparent conductive layer is formed, and then make the two substrates match the box.

Ultraviolet beams are used to irradiate the first substrate 10 and the second substrate 11 vertically respectively, and voltages are respectively applied to the first substrate 10 and the second substrate 11 through the transparent conductive layers on the first substrate 10 and the second substrate 11, so that the first substrate An electric field is formed between 10 and the second substrate 11, so that the prepolymer reacts to form a polymer under the simultaneous action of the ultraviolet beam and the electric field, forming a polymer dispersed liquid crystal layer.

As shown in FIG. 5 , it is used to represent the distribution diagram of each phase of the prepolymer 6 and the liquid crystal molecules 7 in the state of voltage application. Referring to FIG. 5 , under the action of an electric field, the prepolymer 6 and the liquid crystal molecules 7 are uniformly mixed, And it is oriented perpendicular to the direction of the two substrates.

Optimally, in the preparation method described in the specific embodiment of the present invention, a mask plate with a plurality of microholes arranged in an array is also provided on the outside of the first substrate 10 and the second substrate 11, that is, the one shown in FIG. 4 The first mask plate 12 and the second mask plate 13, the first mask plate 12 is formed with a plurality of first microholes 121, and the second mask plate 13 is formed with a plurality of second microholes 131, so that through The ultraviolet light passing through the first mask plate 12 and the second mask plate 13 forms a plurality of tiny ultraviolet light beams, which are used to vertically irradiate the first substrate 10 and the second substrate 11 respectively.

By adopting the preparation method of the above-mentioned structure in the specific embodiment of the present invention, the first mask plate 12 and the second mask plate 13 only transmit light at the first microhole 121 and the second microhole 131 respectively, forming extremely thin beams of light, causing At the same time, the liquid crystal molecules 7 are oriented perpendicular to the two substrates under the action of the electric field, and the molecular chains of the prepolymer 6 close to the first substrate 10 and the second substrate 11, due to the resistance of the light source and the liquid crystal molecules 7, will be along the Similar to vertical orientation polymerization, a polymer fiber network structure is formed. According to the principle of the lowest energy, the liquid crystal molecules 7 tend to be aligned parallel to the surface of the polymer fibers 15, as shown in Figure 6, so the liquid crystal molecules 7 are randomly arranged when the power is off. In this state, there is a tendency to be oriented perpendicular to the two substrates, so when an electric field is applied, the movement resistance of the liquid crystal molecules 7 moving in the direction perpendicular to the two substrates is reduced, and the response speed becomes faster, and a fast-response PDLC is prepared.

In the preparation method described in the specific embodiment of the present invention, the diameter of the ultraviolet light beam is 0.01 micron to 10 micron.

Optimally 0.1 micron to 1 micron.

And preferably, the irradiation intensity of the ultraviolet light beam is 5 milliwatts per square centimeter to 10 milliwatts per square centimeter, and the irradiation time is 10 to 20 minutes.

In addition, the preparation of the first microhole 121 on the first mask plate 12, and the preparation of the second microhole 131 on the second mask plate 13 can adopt any of the following methods:

1) Printing anti-ultraviolet glue (polyurethane-based glue, fluorine-silicon-based glue, etc.) on plastic paper (wax paper) with multiple micropores to make the first mask 12 and the second mask 13;

2) The first mask plate 12 and the second mask plate 13 are made by punching holes at intervals on the surface of the plastic paper printed with anti-ultraviolet adhesive at a micron level;

3) Coating and printing anti-ultraviolet glue (polyurethane matrix glue, fluorosilicon matrix glue) on the surface of the plexiglass to make the first mask plate 12 and the second mask plate 13;

4) Laser ablation or patterning process (usually including photoresist coating, exposure, development, etching, photoresist stripping, etc.) The first mask plate 12 and the second mask plate 13 . In the preparation method described in the specific embodiment of the present invention, the voltage applied to the transparent conductive layer on the first substrate 10 and the second substrate 11 should be 30 volts to 40 volts.

Preferably, the prepolymer is an acrylate material or an epoxy material. The weight percentage of the prepolymer in the mixture is 30% to 40%.

Preferably, a photoinitiator is added to the mixed system of the prepolymer and the liquid crystal molecules, so as to make the polymerization reaction of the prepolymer faster and more uniform. Wherein the weight percentage of the photoinitiator in the mixture is 1% to 3%.

And preferably, the photoinitiator is selected from hydroxycyclohexyl phenyl ketone (HCPK) or 2-hydroxy-2-methyl-1-phenyl-1-propanone (HMPP), etc. One or more of the initiators of the resin system. In the liquid crystal display panel prepared by the preparation method, the driving voltage of PDLC is less than 20 volts, which greatly shortens the response time of liquid crystal molecules.

In the preparation method, the light irradiation unit for forming multiple micron-scale ultraviolet beams is not limited to the above-mentioned structure, and may also adopt a structure that directly emits micron-scale ultraviolet beams through the light emitter.

The preparation method described in the specific embodiment of the present invention forms a plurality of micron-level ultraviolet light beams to irradiate the mixed system of the prepolymer and the liquid crystal molecules, so that orderly orientation polymerization occurs in the mixed system, and polymers are formed in the system. Fiber network structure, the liquid crystal molecules are oriented parallel to the surface of the fiber due to the law of the lowest energy, so the fiber network structure perpendicular to the direction of the two substrates will reduce the resistance of the liquid crystal molecules to move in the direction perpendicular to the two substrates, when the voltage is applied, the liquid crystal molecules The driving force required to turn to the direction perpendicular to the two substrates is reduced, the speed of movement is accelerated, and the response time is reduced.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also It should be regarded as the protection scope of the present invention.

Claims (10)

1. A preparation method for a liquid crystal display panel, the liquid crystal display panel comprising two oppositely arranged substrates and a polymer dispersed liquid crystal layer arranged between the two substrates, the two substrates facing towards the polymerization A transparent conductive layer is formed on one side of the material-dispersed liquid crystal layer, and it is characterized in that the preparation method comprises: Forming transparent conductive layers on the two substrates respectively; Carrying out cell alignment treatment on the two substrates to form a liquid crystal cell, in the liquid crystal cell, the surfaces of the two substrates on which the transparent conductive layer is formed face each other, and a pre-polymerization film is arranged between the two substrates. A mixture of substances and liquid crystals; The two substrates are irradiated vertically with an ultraviolet beam, and a voltage is applied to the two substrates through the transparent conductive layer to form an electric field between the two substrates, and the liquid crystal and the prepolymer are mixed evenly under the action of the electric field, and the vertical Orienting the two substrates, the prepolymer reacts to form a polymer under the action of the ultraviolet beam and the applied voltage to form an electric field at the same time, forming a polymer dispersed liquid crystal layer; Wherein the prepolymer is acrylate material or epoxy resin material. 2. The preparation method according to claim 1, wherein the vertically irradiating the two substrates with an ultraviolet beam comprises: Through the mask plate with a plurality of microholes arranged in an array, the ultraviolet light forms a plurality of ultraviolet light beams for vertically irradiating the two substrates. 3. The preparation method according to claim 1 or 2, characterized in that, the diameter of the ultraviolet light beam is on the order of microns. 4. The preparation method according to claim 3, characterized in that, the diameter of the ultraviolet light beam is 0.01 micron to 10 micron. 5. The preparation method according to claim 4, characterized in that, the diameter of the ultraviolet light beam is 0.1 micron to 1 micron. 6. The preparation method according to claim 1 or 2, wherein the irradiation intensity of the ultraviolet light beam is 5 mW/cm2 to 10 mW/cm2. 7. The preparation method according to claim 1 or 2, wherein the voltage applied to the two substrates is 30 volts to 40 volts. 8. The preparation method according to claim 1, characterized in that, the weight percentage of the prepolymer in the mixture is 30% to 40%. 9. preparation method as claimed in claim 1, is characterized in that, in the mixture of described prepolymer and described liquid crystal, also be added with photoinitiator, wherein the weight percent of described photoinitiator in described mixture From one percent to three percent. 10. preparation method as claimed in claim 9, is characterized in that, described photoinitiator is selected from in hydroxycyclohexyl phenyl ketone, 2-hydroxyl-2-methyl-1-phenyl-1-acetone one or more.