CN111650794A

CN111650794A - Small-deformation cholesteric liquid crystal display device and manufacturing method thereof

Info

Publication number: CN111650794A
Application number: CN202010628220.4A
Authority: CN
Inventors: 赵景罡
Original assignee: Dalian Longning Technology Co ltd
Current assignee: Dalian Longning Technology Co ltd
Priority date: 2020-07-02
Filing date: 2020-07-02
Publication date: 2020-09-11

Abstract

The invention provides a small deformation cholesteric liquid crystal display device and a manufacturing method thereof, wherein the display device comprises: comprises upper and lower film substrates which are relatively parallel and a film which is attached to the inner surface of the film substrate and has patterning or non-patterning, wherein the film comprises but is not limited to an electrode film, an insulating film and an orientation film; the film substrate and/or the film are/is characterized in that a plurality of interval structures with high-strength cohesiveness are distributed between the upper film substrate and the lower film substrate, each interval structure at least comprises two connecting structures with concave-convex inlaying, and two ends of each interval structure are in contact with the inner surfaces of the film substrates and/or the films. The invention can ensure that the cholesteric liquid crystal display device generates smaller deformation under the action of external force so as to keep the stability of the display state, and can ensure the display performance of the cholesteric liquid crystal display device particularly under the working mode of gray scale display. Meanwhile, the manufacturing method is that liquid crystal is dripped in advance before the two film substrates are attached to form a box, and the manufacturing method is suitable for manufacturing and processing the large-screen cholesteric liquid crystal display device.

Description

Small-deformation cholesteric liquid crystal display device and manufacturing method thereof

Technical Field

The invention relates to the technical field of cholesteric liquid crystal display, in particular to a small-deformation cholesteric liquid crystal display device and a manufacturing method thereof.

Background

Color electronic paper display devices are a large category of display devices, which are different from tft (thin Film transistor) liquid crystal display devices and Organic Light Emitting Diode (OLED) display devices, and are expected to gradually occupy a place in the future. The remarkable characteristic is that the display content can be kept unchanged for a period of time even if no power supply is supplied.

The color electronic paper display device is being studied with a view to realizing a high color saturation, and the color electronic paper may be classified into an electrophoretic type, a cholesteric liquid crystal type, an electrowetting type, an electrophoretic/cholesteric liquid crystal hybrid type, and the like, according to a display mode. The electrophoresis type is a type of moving charged particles having different colors in a vacuum, a gas, or a liquid. The cholesteric liquid crystal type realizes color display by selectively reflecting light of different wavelengths by changing the arrangement form of cholesteric liquid crystal molecules. The electrowetting type is a type in which the wettability of a liquid droplet on a substrate, that is, a contact angle is changed by changing a voltage between the liquid droplet and an insulating substrate, and the liquid droplet is deformed or displaced. The color electronic paper adopting the electrophoresis/cholesteric liquid crystal mixing mode realizes the control of the reflection or absorption of light with a certain wavelength or a certain area wavelength and the control of the reflection or absorption of light with another area wavelength by cholesteric liquid crystal molecules with selective reflection characteristics by utilizing the characteristics of electrophoretic particles, and can also realize color display by simultaneously controlling the light with the same wavelength.

In the various modes of the color electronic paper, the advantages of the various display modes are different when the light with different wavelengths, particularly the gray scale, is displayed. The cholesteric liquid crystal type can regulate and control the reflection of one color or the transmission of light in the whole visible light spectrum region by liquid crystal molecules, so that color display can be realized by lamination, and the characteristic provides favorable conditions for adopting an electrophoresis/cholesteric liquid crystal mixing mode. Therefore, the electrophoretic/cholesteric liquid crystal hybrid system has an absolute advantage in color display in that advantages of various systems can be exhibited to the maximum extent as compared with other single systems such as the above-described electrophoretic system, cholesteric liquid crystal system, and electrowetting system. In the case of the single mode, the refresh rate, gray scale, and color saturation of the color display device are limited due to factors such as color filter transmittance, electrophoretic particle separation and mixing, electrowetting fluid coloring, and the like. Therefore, a display device that uses a single mode to realize colors faces a great obstacle to its color characteristics.

As described above, the electrophoretic/cholesteric liquid crystal system is advantageous in color performance of electronic paper, but it is not sufficient to realize only color display in color electronic paper including the cholesteric liquid crystal system. The reason for this is that the cholesteric liquid crystal is liquid, and when the cholesteric liquid crystal layer is deformed by being bent or pressed by an external force, the display state changes accordingly. The cholesteric liquid crystal flows due to the external force applied to the liquid crystal box, so that certain display states are changed, particularly when the display state in the focal conic state is pressed, the display state is completely converted into a planar state, the display state cannot be restored to the state before pressing until the display state is driven to refresh again, and otherwise, the display state cannot be restored.

How to improve the stable display performance of the color electronic paper containing cholesteric liquid crystal under the action of external force is a fundamental problem of the mixed color electronic paper, especially in the display state of a non-planar state. The cholesteric liquid crystal display mode requires a uniform liquid crystal layer having a thickness of several micrometers and a liquid crystal cell formed between upper and lower substrates. In order to form a uniform liquid crystal layer, the prior art is divided into several ways: (1) the spacer structure is formed using an organic or inorganic spherical or rod-shaped spacer material, typically using a dispersion method. (2) A ps (photospacer) material is used to form a spacer structure of a specific shape on a certain substrate through a series of processes by photolithography. The spacer structure is attached to a substrate at a constant density, but the conventional processing method cannot achieve stable cholesteric liquid crystal display performance.

The prior art alleviates the display performance change caused by the deformation generated by pressing through the following procedures, specifically: (1) and manufacturing an electrode pattern on the lower substrate. (2) A PS thin film is formed on the electrode pattern. (3) The PS film is exposed through a photomask. (4) And etching the exposed PS film by using a developing solution to form a spacing structure pattern. (5) And the upper substrate and the lower substrate are attached with preset patterns. (6) And (4) pressurizing and heating. (7) Vacuum liquid crystal injection and the like. In the processes (1) to (4), the tip portion of the spacer structure is made wider than the other portions of the spacer structure, and a part of the spacer structure is bonded to the electrode surface, thereby improving the adhesion between the spacer structure and the upper substrate. Therefore, the spacer structure can be reduced in lateral width, and the spacer structure can be prevented from being peeled off even in the developing process in the photolithography step.

The interval structure pattern has certain viscosity after the development, and the bonding of the upper substrate and the lower substrate can be realized through pressurization and heating treatment, so that the deformation of the display device is reduced. However, the above method has the following disadvantages: after the etching of the developing solution, the viscosity of the PS film is poor, and even the PS film is heated and pressurized, the contact area between the spacing structure and the substrate needs to keep a certain value, which is not beneficial to improving the resolution of the color electronic paper; the unstable chemical components in the spacer structure need to be removed by bonding synchronous heating or bonding first and then heating, otherwise the bonding property between the spacer structure and the substrate after development cannot be ensured. Furthermore, in such a process, the liquid crystal can be injected only through the liquid crystal injection port by vacuum injection. In the production process of the large-size color electronic paper, the production efficiency is low and the cost is high.

In view of the above, in order to apply cholesteric liquid crystal to color electronic paper, it is an important research subject to realize a cholesteric liquid crystal display device in which the display state does not change even if the electronic paper is pressed or bent, and it is very necessary to develop a new spacer structure and a manufacturing method to solve the problem of cholesteric liquid crystal in the application process of color electronic paper.

Disclosure of Invention

According to the color electronic paper containing cholesteric liquid crystal, especially the technical problems that the display performance of the color electronic paper, such as gray scale, resolution and the like, is influenced by the deformation of the cholesteric liquid crystal box in the display device and the production efficiency is influenced by vacuum infusion in the manufacturing process of the color electronic paper with larger size are solved. The invention mainly adds the spacing structure with high-strength cohesiveness between the upper film substrate and the lower film substrate, the spacing structure at least comprises two parts of structures with concave-convex inlaying, and the spacing structure is matched with the sealing frame, so that the production with strong shock resistance, high efficiency and low cost is realized, and the high-resolution display of the large-size color electronic paper is realized by small deformation.

The technical means adopted by the invention are as follows:

a small deformation cholesteric liquid crystal display device, the display device comprising: comprises relatively parallel upper and lower thin film substrates and a patterned or non-patterned thin film attached to the inner surface of the thin film substrate, wherein the thin film includes but is not limited to an electrode thin film, an insulating film, an orientation film and the like; it is characterized in that the preparation method is characterized in that,

a plurality of interval structures with high-strength cohesiveness are distributed between the upper film substrate and the lower film substrate, each interval structure at least comprises two connecting structures with concave-convex embedded structures, and two ends of each interval structure are in contact with the inner surfaces of the film substrates and/or the films.

The electrode films mentioned above are in a rectangular strip shape in practical application, the distance between the electrode films is usually less than 50 μm, the electrode films are of a type in which a transparent electrode is disposed in the display region, and the lead electrode connecting the pixel electrode and the driving IC may be formed of a lead electrode with low sheet resistance or a lead electrode with a transparent ITO electrode. The overlapping area is specifically set according to the wiring structure of the display device, an insulating film such as silicon oxide or silicon nitride can be arranged in the middle, and via holes are arranged on the insulating film to connect all parts of the electrode films.

The alignment film is usually disposed over the entire effective display area, also called AA (active area), and does not require a fine patterning process for each display device, but only covers the entire AA area and does not exceed the sealing frame. In the lead electrode or the blank region in the AA region, an alignment film is also generally provided. In the manufacture of liquid crystal, the adjustment of working procedures is very difficult, and the simplification process is difficult and expensive on the premise of not influencing the display performance. In order to adapt to the process flow of the production line, a cholesteric liquid crystal display device with a single-side orientation film can also be arranged, and a layer of protective film is arranged on the surface of an electrode film on the other side without the orientation film, so that the electrodes, particularly metal electrodes, are prevented from slowly seeping to pollute the display liquid crystal material, and the display stability is influenced by conductive impurities in the liquid crystal display material. The insulating film is patterned in a manner similar to that of the alignment film.

When the material of the spacer structure is in contact with the alignment film or the insulating film, good stability and film formation characteristics are required. The sealing frame portion of the sealing structure is in contact with ITO or a metal electrode, and is also required to have good stability and film forming characteristics.

Furthermore, the spacing structure is formed by respectively and correspondingly processing two types of resin mixtures with different characteristics, and the two types of cured resin mixtures form a connecting structure with concave-convex mosaic at the connecting position. In which a resin material is patterned in various ways, such as APR printing, gravure printing, screen printing, inkjet printing, photolithography, and the like, in order to have patterning characteristics. In consideration of process maturity and pattern fineness, a preferred scheme of the high-resolution color electronic paper manufacturing process is photolithography, and the formed resin pattern is not easily peeled off. The requirements for another resin material are: (1) it is difficult for the liquid crystal display material to diffuse and precipitate before being cured; (2) easy positioning in forming the pattern is enough, and the preferable scheme is ink-jet printing; (3) has good adhesion to various films.

Further, the spacing structure is composed of a connecting structure I and a connecting structure II which are embedded in a concave-convex mode, at least one side end portion of the connecting structure I is in contact with the inner surface of the upper (or lower) film substrate and/or the film and has a completely or partially hollow outer side structure, the connecting structure II is a solid structure embedded in the connecting structure I, and at least one side end portion of the connecting structure II is in contact with the inner surface of the lower (or upper) film substrate and/or the film.

Furthermore, the connecting structure II is embedded in the connecting structure I, and one side end of the connecting structure II is provided with an extension part wrapping the outer side structure.

Further, one or a plurality of hollow parts can be arranged in the outer side structure according to requirements, and a columnar or other filling structure can be arranged in the hollow parts.

The convex-concave mosaic connecting structure has the advantages that: the two materials are respectively connected with the upper film substrate and the lower film substrate, one material can be fixed on one film substrate in a patterning mode, and the patterning material is not required to be adhered to the other film substrate in the processing process, namely, the material is adhered to one film substrate. Before the two film substrates are attached, the requirement on another resin bonding material is that the liquid crystal material is kept stable and is not easy to diffuse into liquid crystal, so that cholesteric liquid crystal is dripped before the attaching process and then attached, the cholesteric liquid crystal injection time and the sealing process are saved, the production efficiency of the liquid crystal panel is improved, and the production cost is reduced.

Further, along the normal direction of the film substrate, the two ends of the spacer structure have tight connectivity with at least all or part of the contact surfaces of the upper and lower film substrates, the electrode films, the insulating films or the orientation films, and the two ends of the spacer structure refer to the end surfaces of the two ends or the side wall portions of the end portions. Both ends of the spacer structure in the normal direction of the film substrate may be in contact with the ITO electrode, the insulating film, and the alignment film, and must be in firm contact with the surface of the medium to satisfy the requirement of small deformation of the cholesteric liquid crystal layer. The spacer structure has long term stable performance in cholesteric liquid crystals.

Further, the connecting structure I is formed by pretreating and curing a photoresist mixture with certain hardness, wherein the photoresist mixture is formed by processing acrylate resin, an acrylate monomer, a photoinitiator, 3-methoxybutyl acetate, propylene glycol methyl ether acetate and cyclohexanone solution; the connecting structure II is formed by pretreating and curing an ultraviolet heat curing adhesive mixture I with certain cohesiveness, and the ultraviolet heat curing adhesive mixture I is processed by liquid epoxy resin, a latent epoxy curing agent and a compound containing more than 2 thiol groups per molecule.

The acrylate resin and the acrylate monomer are alkali-soluble carboxyl-containing high-molecular compounds such as copolymers of carboxyl-containing monofunctional unsaturated compounds and monofunctional compounds having unsaturated double bonds. The film formed by the solution is irradiated by ultraviolet light, and the solubility of the film in an alkaline developing solution is weakened after the acrylate monomer in the film is subjected to polymerization reaction under the action of a photoinitiator. The part not irradiated by ultraviolet light is more easily dissolved in an alkaline developer than the part irradiated by ultraviolet light, and a fine pattern is formed by utilizing the characteristic. The propylene glycol methyl ether acetate is called PGMEA for short, and the solid content in the solution is adjusted together with the acetic acid (3-methoxybutyl) ester and the cyclohexanone, so that the requirements of different equipment are met.

The viscosity of the ultraviolet heat curing adhesive mixture I of the material of the connecting structure II is larger than that of the photoresist mixture of the material of the connecting structure I, once the pattern of the connecting structure I is formed, the cohesiveness is weakened, and particularly after ultraviolet irradiation, if the solvent is further removed and the material is heated to a high temperature of more than 200 ℃, the cohesiveness almost disappears. Therefore, in the prior art, in order to bond another film substrate, the upper film substrate and the lower film substrate must be bonded at a low temperature, and then the solvent is removed at a high temperature, and if the solvent enters the liquid crystal, the display performance is seriously affected. Therefore, only the liquid crystal can be poured in vacuum. The vacuum filling of liquid crystal is performed for more than 10 inches or more, which takes several hours or tens of hours. The production efficiency is very low.

The material of the connecting structure II has contact stability with cholesteric liquid crystal before curing and has the separation characteristic among molecules. The separation property between molecules ensures that the cholesteric liquid crystal molecules do not influence the adhesion of the solid structure material and the film substrate in the process of forming the liquid crystal box when the liquid crystal box is attached.

Preferably, the surface of the resin material of the spacer structure forming the connecting structure II before bonding is higher than the liquid level of the cholesteric liquid crystal. The connection structure I part forms a required pattern through a photoetching process, the acrylate monomer is further polymerized under the action of ultraviolet light, and the acrylate resin forms an interval structure with certain hardness at a certain temperature. The part of the structure is coated on the film substrate in a liquid state, and has good bonding performance with the film substrate after treatment, so that the bonding of the spacing structure and the film substrate is ensured. The mixture composed of liquid epoxy resin, latent epoxy curing agent and compound containing more than 2 thiol groups per molecule is filled into the outer structure by adjusting the solid content through N-methyl pyrrolidone or other solvents. The latent epoxy curing agent and the compound containing more than 2 thiol groups per molecule are used for reducing the curing temperature of the epoxy resin, and the epoxy resin is heated and cured after being attached, wherein the temperature can be as low as a clearing point close to cholesteric liquid crystal. The filling amount is determined according to the solid content, and when the solvent is volatilized, the amount exceeding the surface of the outer side structure is preferably less than 10% by volume of the entire spacer structure.

Further, the thickness of the upper and lower thin film substrates is less than 200 μm; the projections of different films on the normal direction of the upper film substrate and the lower film substrate are partially overlapped or completely overlapped; the height of the spacing structure is between 2 and 5 mu m.

The thickness of the film substrate is less than 200 μm, the impulse is easily absorbed by the spacer structure when the film substrate is thinner and the cholesteric liquid crystal layer is less deformed when an external force is applied. The size of the spacing structure is limited by the resolution size of the display, and the spacing structure cannot be designed at will, and only the structures at two ends can be optimized to meet the performance requirement of the display device. The thinner the film substrate is, the higher the flexibility is, the lower the elasticity is, and the easier the interval structure restrains the deformation of the film substrate. Small deformation cells can be formed as long as the density is high enough, very small (a few microns or tens of microns) spacer structures. Meanwhile, in the laminated color electronic paper display device, the thinner the substrate is, the more favorable the color mixing effect is, and the material of the film substrate may be a transparent material such as plastic or glass.

Furthermore, an auxiliary spacing structure for assisting in adjusting the supporting force between the film substrates is arranged between the upper film substrate and the lower film substrate, and the total cross-sectional area of the auxiliary spacing structure is not more than 5% of the effective display area.

Furthermore, the auxiliary spacing structure is made of the same material as the connecting structure I.

The height of the auxiliary spacing structure is 2-5 μm, the area of the solid structure is as small as possible, and the solid structure is required to have relatively high supporting capacity. In the operating temperature range of the display device, the elastic modulus is required to be in the range of 0.1-1GPa at a compression amount of about 15%.

Further, the electrode thin film is transparent or non-transparent, and the orientation film is arranged on the outermost layer of each thin film on the inner side of the upper thin film substrate and/or the lower thin film substrate.

The electrode film has two kinds of transparency and opacity, the opaque electrode is usually a metal electrode, can be copper, molybdenum, aluminum, chromium or each layer is superposed, and the lamination structure of molybdenum, aluminum and molybdenum is preferably used in the aspect of cost and stability; the transparent electrode is usually a metal oxide electrode such as tin or indium, and preferably an ITO electrode. In flexible display, it is preferable to use a material such as a silver nanowire, graphene, PEDOT/PSS (poly 3, 4-ethylenedioxythiophene/polystyrenesulfonic acid) or the like for the transparent electrode. The transparent electrode film can be used for the display electrode part and can also be superposed with the metal electrode for the non-display electrode part, and the higher the resolution ratio is, the smaller the electrode distance is required to be.

The alignment film may be provided only on the upper film substrate side or only on the lower film substrate side. The orientation film is in direct contact with the cholesteric liquid crystal layer, and increases the degree of order of the cholesteric liquid crystal during the anchoring process of the liquid crystal, and a homeotropic orientation film is preferable. In the formation of each layer of thin film, bm (black matrix), oc (over coat) layer, electrode thin film and insulating film are first patterned, and the thin film required for patterning, orientation film coating and spacer formation are sputtered or evaporated, and may be formed in this order. After each layer of thin film is formed, corresponding patterning treatment is performed as required. However, in the process flow of the existing production line, the process flow is often different, the cost for resetting the process flow is extremely high, and the single-layer alignment film can be used to save the manufacturing cost.

In the invention, the orientation film can be coated to manufacture the orientation film after the outer structure is formed, and the process is favorable for processing the outer structure in different workshops. The prior art requires that the alignment film be processed prior to all parts of the spacer structure, which would otherwise affect the adhesion properties of the spacer structure. The present invention does not affect the adhesion of the spacer structure even if the alignment film is coated after the formation of the outer structure, which is an advantage of the present invention over the prior art.

Furthermore, the display device also comprises a sealing frame arranged between the upper film substrate and the lower film substrate, and the sealing frame seals the cholesteric liquid crystal in the closed space after the cholesteric liquid crystal forms a uniform liquid crystal layer according to the thickness of the interval structure.

Furthermore, the sealing frame at least comprises an inner frame and an outer frame with certain cohesiveness, and also comprises a frame spacing structure arranged between the inner frame and the outer frame; the inner frame and the outer frame are made of the same material as the connecting structure I; the frame interval structure is a small column-shaped or other solid structure, the frame interval structure is formed by pretreating and curing an ultraviolet heat curing adhesive mixture II with certain cohesiveness, and the ultraviolet heat curing adhesive mixture II is processed by liquid epoxy resin, acrylate monomer and/or methacrylate monomer or oligomer thereof, a latent epoxy curing agent, a photo-free radical polymerization initiator and a mixture containing more than 2 thiol group compounds per molecule and is filled in the inner frame and the outer frame.

Furthermore, the sealing frame at least comprises an inner frame and an outer frame with certain cohesiveness, and also comprises a frame spacing structure arranged between the inner frame and the outer frame; the inner frame, the outer frame and the frame interval structure are formed by pretreating and curing an ultraviolet heat curing adhesive mixture II with certain cohesiveness, wherein the ultraviolet heat curing adhesive mixture II is processed by liquid epoxy resin, acrylate monomers and/or methacrylate monomers or oligomers thereof, a latent epoxy curing agent, a photo-free radical polymerization initiator and a mixture containing more than 2 thiol group compounds per molecule.

The ultraviolet heat curing adhesive mixture II has stronger viscosity, can be subjected to light curing under the action of ultraviolet light, and can also be subjected to heat curing at a certain temperature. The required heat curing temperature is set according to the nature of the latent epoxy curing agent in combination with the process requirements. Meanwhile, compared with the mixture for forming a solid structure, the mixture is not easy to form a fine pattern, is difficult to form a uniform pattern of tens of microns or several microns, and is only suitable for a display device with a wider sealing frame when being used independently. By combining the two materials with the characteristics, the spacing structure and the upper and lower film substrates can be effectively and firmly bonded together to form a narrower sealing frame, and the display device with the narrower sealing frame is applied.

The invention also discloses a manufacturing method of the small deformation cholesteric liquid crystal display device, which is characterized in that the manufacturing method is used for manufacturing the small deformation cholesteric liquid crystal display device and comprises the following steps:

s1, cleaning: cleaning the film substrate and the film which is attached to the inner surface of the film substrate and has patterning or non-patterning; the cleaning comprises excimer ultraviolet irradiation, cleaning liquid scrubbing, two-fluid high-pressure pure water spraying, pure water direct spraying, air knife drying and the like.

S2, preparing a spacing structure: selecting an upper (or lower) film substrate, coating a photoresist mixture on the inner surface of the film substrate by using spin and slit methods, and forming a connecting structure I by pre-curing, exposing, developing by using an alkaline solution, cleaning and curing; slit followed by spin coating, drying under reduced pressure, edge or back cleaning and pre-baking, etc. are typically performed.

Filling the ultraviolet heat curing glue mixture I into the connecting structure I by using a printing method or an ink-jet printing method, and heating to volatilize a solvent in the mixture to obtain a connecting structure II;

further, while the connection structure i is prepared in step S2, the inner frame and the outer frame of the sealing frame are prepared in the same manner, and the frame spacer structure is obtained by filling the ultraviolet curing adhesive mixture ii into the sealing frame.

The structure inside the connecting structure I can be simultaneously manufactured and provided with columnar or other hollow structures and patterns with other shapes by using the same method. The cleaning is performed by circulating direct injection of pure water, air knife drying, and the like.

S3, filling and preparing a cholesteric liquid crystal layer: filling cholesteric liquid crystal into a space surrounded by the sealed frame by using a dripping method, wherein the surface of the connecting structure II is still higher than the liquid level of the cholesteric liquid crystal after the solvent is volatilized; after the liquid crystal is instilled, the lower (or upper) film substrate is jointed, and a liquid crystal box is pressed by using proper atmospheric pressure to form a uniform liquid crystal layer;

s4, curing and packaging: and carrying out photocuring on the liquid crystal box, and then carrying out thermocuring to obtain the small-deformation cholesteric liquid crystal display device.

Compared with the prior art, the cholesteric liquid crystal display device has the advantages that the cholesteric liquid crystal display device can be guaranteed to deform slightly under the action of external force through the arrangement of the spacing structure, so that the stability of the display state is kept, and particularly, the display performance of the cholesteric liquid crystal display device can be guaranteed in the working mode of gray scale display. Meanwhile, the spacing structure is matched with the sealing frame, a mode of firstly dripping cholesteric liquid crystal materials can be adopted in the manufacturing process and then the cholesteric liquid crystal materials are attached, liquid crystal is dripped in advance before the two film substrates are attached, and then the liquid crystal box is formed.

The invention is suitable for the display requirement of high resolution, has small deformation to realize the high resolution display of large-size color electronic paper, can be produced with high efficiency and low cost, and has strong shock resistance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a small deformation cholesteric liquid crystal display device according to the invention.

Fig. 2 is a schematic structural diagram of the spacer structure and the outer structure of the sealing frame of the small deformation cholesteric liquid crystal display device of the invention bonded to a single-sided film substrate.

FIG. 3 is a schematic sectional view (B-B) of the connecting structure I of the present invention having a completely hollow structure^|)。

FIG. 4 is a cross section (B-B) of the connecting structure I of the present invention having a partially hollow structure (U-shaped structure)^|)。

FIG. 5 shows a connecting structure I according to the invention withSchematic cross-sectional view of solid Structure (B-B)^|)。

FIG. 6 is a schematic cross-sectional view (B-B) of the connecting structure I of the present invention having a partially hollow structure (U-shaped structure) and one or more hollow portions provided therein^|)。

FIG. 7 is a schematic cross-sectional view of the ultraviolet heat-curable adhesive mixture II of the present invention filled into the connection structure I shown in FIG. 3.

FIG. 8 is a schematic cross-sectional view of the ultraviolet heat-curable adhesive mixture II of the present invention filled into the connection structure I shown in FIG. 4.

FIG. 9 is a schematic cross-sectional view of the ultraviolet heat-curable adhesive mixture II of the present invention filled into the connection structure I shown in FIG. 5.

FIG. 10 is a schematic cross-sectional view of the present invention after curing the connection structure I and connection structure II shown in FIG. 7 between upper and lower thin-film substrates.

FIG. 11 is a schematic cross-sectional view of the connection structure I and connection structure II of FIG. 8 after curing between upper and lower thin-film substrates according to the present invention.

FIG. 12 is a schematic cross-sectional view of the connection structure I and connection structure II of FIG. 9 after curing between upper and lower thin-film substrates according to the present invention.

FIG. 13 is a schematic view of the inner and outer frames and the frame spacing structure of the sealed frame of the present invention.

In the figure: 1. an upper thin film substrate; 2. a lower film substrate; 3. a patterned or unpatterned film attached to the upper substrate; 4. a patterned or unpatterned film attached to the lower substrate; 5. sealing the frame; 6. a spacer structure; 7. cholesteric liquid crystal; 8. a connecting structure I; 9. a UV thermal curing glue mixture II; 10. a connecting structure II; 11. an inner frame; 12. an outer frame; 13. and a frame interval structure.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. Any specific values in all examples shown and discussed herein are to be construed as exemplary only and not as limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the absence of any contrary indication, these directional terms are not intended to indicate and imply that the device or element so referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be considered as limiting the scope of the present invention: the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

As shown in fig. 1 and fig. 2, the present invention provides a small deformation cholesteric liquid crystal display device, including: comprises an upper film substrate 1, a lower film substrate 2, a patterned or non-patterned film 3 attached to the upper substrate, a patterned or non-patterned film 4 attached to the lower substrate, which include but are not limited to electrode films, insulating films, and orientation films, etc. The electrode thin film is transparent or non-transparent, and the orientation film is arranged on the outermost layer of each thin film on the inner side of the upper thin film substrate 1 and/or the lower thin film substrate 2.

A plurality of spacing structures 6 with high-strength cohesiveness are distributed between the upper film substrate 1 and the lower film substrate 2, and the spacing structures can be uniformly distributed between the film substrates and also can be arranged according to actual needs. The spacing structure 6 is at least composed of two connecting structures with concave-convex embedded structures, and two ends of the spacing structure 6 are in contact with the inner surface of the film substrate and/or the film, namely two ends of the spacing structure 6 can be in contact with the inner surface of the film substrate at the same time, can also be in contact with the inner surface of the film at the same time, or one side of the spacing structure is in contact with one side of the film substrate. Along the normal direction of the film substrate, the two ends of the spacing structure 6 at least have close connectivity with all or part of the contact surfaces of the upper and lower film substrates, the electrode film, the insulating film or the orientation film, the two ends of the spacing structure 6 refer to the end surfaces of the two ends or the side wall parts of the end parts, and because of the multi-layer overlapping of the films, there will be close connectivity in the microstructure.

Preferably, the thickness of the upper and lower film substrates is less than 200 μm; the projections of different films on the normal direction of the upper film substrate and the lower film substrate are partially overlapped or completely overlapped; the height of the spacer structures 6 is between 2 and 5 μm.

The spacing structure 6 is formed by respectively and correspondingly processing two types of resin mixtures with different characteristics, and the two types of cured resin mixtures form a connecting structure with concave-convex inlaying at the connecting position.

Specifically, the spacing structure 6 is composed of a connecting structure i 8 and a connecting structure ii 10 which are inlaid in a concave-convex manner, at least one side end of the connecting structure i 8 is in contact with the inner surface of the upper (or lower) film substrate and/or the film and has a completely or partially hollow outer side structure, that is, the connecting structure i 8 may be as shown in the figure, and is a completely hollow structure, that is, the outer side structure is represented by a ring-shaped column, and the cross section of the outer side structure may be an inverted trapezoid, a rectangle or other shapes, and is not limited herein; the connection structure i 8 may also be a partially hollow structure as shown in fig. 4, which shows a U-shaped structure, and the bottom of the U-shaped structure is completely in contact with the lower film substrate 2 and/or the patterned or unpatterned film 4 attached to the lower substrate, where and/or because the film structure has a patterned or unpatterned structure as required, when the hollowed-out regions of the multi-layer pattern overlap, there is always a direct contact with the film substrate. Further, as shown in FIG. 5, the connecting structure I8 may be a solid structure, without a hollow portion.

As shown in fig. 10 to 12, the connection structure ii 10 is a solid structure embedded in the connection structure i, and at least one side end of the connection structure ii 10 is in contact with the inner surface of the lower (or upper) thin film substrate and/or the thin film, fig. 10 shows that both ends of the connection structure ii 10 are in contact with the upper and lower thin film substrates, respectively, and fig. 11 shows that one side end is in contact with the upper thin film substrate 1 and/or the patterned or unpatterned thin film 3 attached to the upper substrate.

As can be seen from the figure, the connecting structure II 10 is embedded in or on the connecting structure I8, and one side end of the connecting structure II 10 is provided with an extension part wrapping the outer side structure, namely the upper end of the connecting structure II 10 is wrapped on the upper end of the connecting structure I8 in an extending mode, so that the connecting structure II is more tightly combined.

Preferably, the inside of the outer side structure (connecting structure i 8) can be provided with one or more hollow parts according to the requirement, and the inside of the hollow part can be provided with a columnar or other-shaped filling structure, namely, a small hollow structure is further arranged in the hollow part in fig. 3 or fig. 4, as shown in fig. 6.

The connecting structure I8 is formed by pretreating and curing a photoresist mixture with certain hardness, wherein the photoresist mixture is formed by processing acrylate resin, an acrylate monomer, a photoinitiator, 3-methoxybutyl acetate, propylene glycol monomethyl ether acetate and cyclohexanone solution; the connecting structure II 10 is formed by pretreating and curing an ultraviolet heat curing adhesive mixture I9 with certain cohesiveness, wherein the ultraviolet heat curing adhesive mixture I9 is formed by processing liquid epoxy resin, a latent epoxy curing agent and a compound containing more than 2 thiol groups per molecule.

As another preferable scheme, an auxiliary spacing structure for assisting in adjusting the supporting force between the film substrates is further arranged between the upper film substrate and the lower film substrate, the material of the auxiliary spacing structure is the same as that of the connecting structure i, and the total cross-sectional area of the auxiliary spacing structure is not more than 5% of the effective display area.

In cooperation with the spacer structure 6, as another preferred embodiment, as shown in fig. 2, the display device further includes a sealing frame 5 disposed between the upper and lower film substrates, the sealing frame 5 forms a uniform liquid crystal layer on the cholesteric liquid crystal 7 according to the thickness of the spacer structure 6 and then seals the liquid crystal layer in the enclosed space, the enclosed space is a space surrounded by the sealing frame 5 disposed on the upper film substrate 1 or the lower film substrate 2, and the cholesteric liquid crystal 7 is stable and does not leak in this area. The specific arrangement of the sealing rim 5 is shown in fig. 13.

Preferably, the sealing frame 5 at least comprises an inner frame 11 and an outer frame 12 with certain cohesiveness, and further comprises a frame spacing structure 13 arranged between the inner frame and the outer frame; the inner frame and the outer frame are made of the same material as the connecting structure I; the frame interval structure 13 is a small column-shaped or other solid structure, the frame interval structure 13 is formed by pretreating and curing an ultraviolet heat curing adhesive mixture II with certain cohesiveness, and the ultraviolet heat curing adhesive mixture II is processed by liquid epoxy resin, acrylate monomer and/or methacrylate monomer or oligomer thereof, latent epoxy curing agent, photo-free radical polymerization initiator and a mixture containing more than 2 thiol group compounds per molecule and is filled in the inner frame and the outer frame.

As another preferred scheme, the sealing frame 5 at least comprises an inner frame 11 and an outer frame 12 with certain cohesiveness, and further comprises a frame spacing structure 13 arranged between the inner frame and the outer frame; the inner frame, the outer frame and the frame interval structure 13 are formed by adopting an ultraviolet heat curing adhesive mixture II with certain cohesiveness through pretreatment and curing, wherein the ultraviolet heat curing adhesive mixture II is processed by liquid epoxy resin, acrylate monomer and/or methacrylate monomer or oligomer thereof, latent epoxy curing agent, photo-free radical polymerization initiator and a mixture containing more than 2 thiol group compounds per molecule.

The invention also discloses a manufacturing method of the small deformation cholesteric liquid crystal display device, which is used for manufacturing the small deformation cholesteric liquid crystal display device and comprises the following steps:

s1, cleaning: cleaning an upper film substrate 1, a lower film substrate 2, a patterned or non-patterned film 3 attached to the upper substrate, and a patterned or non-patterned film 4 attached to the lower substrate;

s2, preparing a spacing structure: selecting a lower film substrate 2, coating a photoresist mixture on the inner surface of the film substrate by using spin and slit methods, and forming a connecting structure I8 through precuring, exposure, development by using an alkaline solution, cleaning and curing;

in step S2, preparing the inner frame and the outer frame of the sealing frame 5 by the same method while preparing the connection structure i 8;

as shown in FIGS. 7-9, the ultraviolet heat-curable adhesive mixture I9 is filled into the connecting structure I8 by using a printing method or an ink-jet printing method, the ultraviolet heat-curable adhesive mixture I9 is a viscous mixture, and as can be seen from the figure, the viscous mixture is confined in a regular or irregular space by the outer structure. In fig. 7, the uv curable adhesive mixture i 9 is in contact with the lower film substrate 2, and both fig. 8 and 9 are not in contact with the lower film substrate 2. It can also be seen that the outer structure may wrap around a portion of the solid structure, and that the solid structure may also wrap around a portion of the outer structure.

Heating to volatilize the solvent in the ultraviolet heat curing glue mixture I9 to obtain a connecting structure II 10; and filling the ultraviolet heat curing adhesive mixture II into the sealed frame 5 to obtain a frame interval structure.

S3, filling and preparing a cholesteric liquid crystal layer: filling the cholesteric liquid crystal 7 into the space surrounded by the sealing frame by using a dripping method; after the liquid crystal is instilled, the upper film substrate 1 is attached, and a liquid crystal box is pressed by using proper atmospheric pressure to form a uniform liquid crystal layer;

As shown in fig. 10, the solid structure wraps around and makes up-and-down contact with a portion of the solid outer structure. The spacing structure 6 of the attached upper and lower film substrates is in close contact with the upper film substrate 1 and the lower film substrate 2. The solidification and bonding of the spacing structure 6 and the film substrate are realized in two steps, and the bonding firmness is ensured. Meanwhile, cholesteric liquid crystal 7 can be injected in the curing process, the existing vacuum injection technology is avoided, the production efficiency is improved, and the cost is reduced.

The small deformation cholesteric liquid crystal display device provided by the invention has the advantages that under the action of pressing, bending or other external forces, the planar state, the focal conic state and the gray state of cholesteric liquid crystal are not changed, and the requirements of display forms such as handwriting input, flexible display and the like are met.

Example 1

A method for manufacturing a small deformation cholesteric liquid crystal display device is used for manufacturing the small deformation cholesteric liquid crystal display device of the embodiment, and specific material types are selected and parameter settings are as follows:

s1, cleaning the film substrate and the various patterned or unpatterned films attached to the inner surface: the electrode film comprises a transparent electrode film and a non-transparent electrode film, wherein the transparent electrode film is made of ITO, and the non-transparent electrode film is made of molybdenum, aluminum and molybdenum; the insulating film is made of silicon nitride; the alignment film used was a vertical alignment film.

S2, coating a photoresist mixture, namely a mixed solution of acrylate resin (12-18%), acrylate monomer (12-18%), photoinitiator (0.8-1.2%), acetic acid (3-methoxybutyl) ester (16-24%), propylene glycol monomethyl ether acetate (16-24%) and cyclohexanone solution (23.2-34.8%) on the inner surface of the upper or lower film substrate by using spin and slit methods, wherein the mixture ratio is only to realize good viscosity and photoetching performance. Slit followed by spin coating, drying under reduced pressure, edge or backside cleaning typically, pre-baking, and the like. spin speed is 900 rpm, and the thickness of the film is 3.5-4.1 μm.

The exposure intensity is set to 80-100mj/cm²The film is developed by using an alkaline solution such as tetramethylammonium hydroxide or potassium hydroxide, and the developing temperature is adjusted according to the beat and is required to be lower than the film pre-curing temperature.

Filling an ultraviolet heat curing adhesive mixture i 9, i.e., a mixture of a liquid epoxy resin (24-36%), a latent epoxy curing agent (0.8-1.2%), and a solvent containing 2 or more thiol groups (0.8-1.2%) and N-methylpyrrolidone (54.4-81.6%) per molecule, into the outer side structure in step S2 using an ink jet printing method; filling an ultraviolet heat curing adhesive mixture II, namely a mixture of liquid epoxy resin (48-72%), acrylate monomer and/or methacrylate monomer or oligomer thereof (29.6-44.4%), latent epoxy curing agent (0.8-1.2%), photo radical polymerization initiator (0.8-1.2%) and compound containing more than 2 thiol groups per molecule (0.8-1.2%) into a sealing frame, and adding a solvent to dilute the mixture according to the requirements of equipment; and heating to volatilize the solvent. If a photo-polymer material is introduced into the material forming the solid structure, in order to reduce the influence of ultraviolet light on the cholesteric liquid crystal, a precise mask used in step S2 is required to block the irradiation.

S3, filling a mixture of MDA-1444 (nematic liquid crystal) and MDA-1445 (cholesteric liquid crystal) of Merck company into the space surrounded by the sealed frame by using a dripping method. The ratio of the two liquid crystals can be determined according to the wavelength of the selective reflection.

After the liquid crystal is instilled, the upper film substrate and the lower film substrate are jointed, and a liquid crystal box is pressed by 0.08 atmosphere to form a uniform cholesteric liquid crystal layer with the thickness of approximately 4 mu m.

And S4, after photo-curing, the photo-curing is to ensure that the sealing frame has certain bonding strength, and then the photo-curing is carried out to further ensure that the interval structure and the sealing frame firmly bond the upper film substrate and the lower film substrate or various films attached to the upper film substrate and the lower film substrate.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; the adjustment of the display device by changing the thickness of the thin film substrate, the density and height of the spacing structure, the proportion of the materials, and the like, is covered in the protection scope of the invention; the invention manufactures the small deformation cholesteric liquid crystal display device according to the fixing sequence and the fixing mode of the spacing structure and the film substrate, and any change of the material type and the proportion of the outer side structure and the solid structure and the known processing mode is an easily-conceived optimization mode. Although the invention is designed in accordance with the requirements of a low distortion cholesteric liquid crystal display device, it also brings obvious benefits for other types of liquid crystal display devices, such as when the display device is bent, the display content remains unchanged. Those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A small deformation cholesteric liquid crystal display device, the display device comprising: comprises relatively parallel upper and lower thin film substrates and a patterned or non-patterned thin film attached to the inner surface of the thin film substrate, wherein the thin film includes but is not limited to an electrode thin film, an insulating film and an orientation film; it is characterized in that the preparation method is characterized in that,

2. A small deformation cholesteric liquid crystal display device according to claim 1, wherein the spacer structure is formed by respectively subjecting two types of resin mixtures having different characteristics to respective processes, and the cured two types of resin mixtures form a connection structure having a concave-convex mosaic at a connection position.

3. A small deformation cholesteric liquid crystal display device according to claim 1, wherein the spacer structure is composed of a connection structure i and a connection structure ii which are engaged with each other in a concavo-convex manner, at least one side end of the connection structure i is in contact with an inner surface of the upper (or lower) film substrate and/or the film and has a completely or partially hollow outer side structure, the connection structure ii is a solid structure engaged in the connection structure i and at least one side end of the connection structure ii is in contact with an inner surface of the lower (or upper) film substrate and/or the film.

4. Small deformation cholesteric liquid crystal display device according to claim 3, wherein one or more hollow parts are arranged inside the outer structure according to the requirement, and a columnar or other filling structure is arranged inside the hollow parts.

5. A small deformation cholesteric liquid crystal display device according to claim 1, wherein both ends of the spacer structure are in close contact with at least all or part of the contact surfaces of the upper and lower film substrates, the electrode films, the insulating films, or the alignment films in a normal direction of the film substrates, and both ends of the spacer structure are end surfaces of both ends or side wall portions of the end portions.

6. The small deformation cholesteric liquid crystal display device of claim 3, wherein the connection structure I is formed by pre-treating and curing a photoresist mixture with certain hardness, and the photoresist mixture is formed by processing acrylate resin, acrylate monomer, photoinitiator, 3-methoxybutyl acetate, propylene glycol monomethyl ether acetate and cyclohexanone solution; the connecting structure II is formed by pretreating and curing an ultraviolet heat curing adhesive mixture I with certain cohesiveness, and the ultraviolet heat curing adhesive mixture I is processed by liquid epoxy resin, a latent epoxy curing agent and a compound containing more than 2 thiol groups per molecule.

7. A small deformation cholesteric liquid crystal display device according to claim 1, wherein the upper and lower film substrates have a thickness of less than 200 μm; the projections of different films on the normal direction of the upper film substrate and the lower film substrate are partially overlapped or completely overlapped; the height of the spacing structure is between 2 and 5 mu m.

8. A small deformation cholesteric liquid crystal display device according to claim 1, wherein an auxiliary spacer structure for assisting in adjusting a supporting force between the upper and lower film substrates is further disposed between the upper and lower film substrates, the auxiliary spacer structure has a total cross-sectional area of not more than 5% of an effective display area, and the auxiliary spacer structure is made of the same material as the connection structure I.

9. A small deformation cholesteric liquid crystal display device according to claim 1, further comprising a sealing frame disposed between the upper and lower film substrates, wherein the sealing frame seals the cholesteric liquid crystal in the enclosed space after forming a uniform liquid crystal layer according to the thickness of the spacer structure; the sealing frame at least comprises an inner frame and an outer frame with certain cohesiveness, and also comprises a frame spacing structure arranged between the inner frame and the outer frame; the inner frame and the outer frame are made of the same material as the connecting structure I; the frame interval structure is a small column-shaped or other solid structure, the frame interval structure is formed by pretreating and curing an ultraviolet heat curing adhesive mixture II with certain cohesiveness, and the ultraviolet heat curing adhesive mixture II is processed by liquid epoxy resin, acrylate monomer and/or methacrylate monomer or oligomer thereof, a latent epoxy curing agent, a photo-free radical polymerization initiator and a mixture containing more than 2 thiol group compounds per molecule and is filled in the inner frame and the outer frame.

10. A method of manufacturing a low distortion cholesteric liquid crystal display device, characterized in that the method of manufacturing a low distortion cholesteric liquid crystal display device according to any one of claims 1 to 9, comprises the steps of:

s1, cleaning: cleaning the film substrate and the film which is attached to the inner surface of the film substrate and has patterning or non-patterning;

s2, preparing a spacing structure: selecting an upper (or lower) film substrate, coating a photoresist mixture on the inner surface of the film substrate by using spin and slit methods, and forming a connecting structure I by pre-curing, exposing, developing by using an alkaline solution, cleaning and curing;

filling the ultraviolet thermal curing adhesive mixture I into the connecting structure I by using a printing method or an ink-jet printing method, and heating to volatilize a solvent in the mixture to obtain a connecting structure II;

s3, filling and preparing a cholesteric liquid crystal layer: filling cholesteric liquid crystal into a space surrounded by the sealing frame by using a dripping method; after the liquid crystal is instilled, the lower (or upper) film substrate is jointed, and a liquid crystal box is pressed by using proper atmospheric pressure to form a uniform liquid crystal layer;