Organic display device and preparation method and application thereof

Abstract

The invention discloses an organic display device and a preparation method and application thereof.The organic display device comprises a first substrate and a second substrate which are oppositely arranged, and the first substrate comprises a first supporting plate and a first electrode layer which are sequentially arranged in the direction towards the second substrate; the second substrate comprises a second supporting plate, a second electrode layer, an organic hydrophobic insulating layer and an organic pixel wall which are sequentially arranged in the direction towards the first substrate, and the organic pixel wall encloses pixel grids; a sealing cavity is formed between the first substrate and the second substrate, and the sealing cavity is filled with organic non-polar developing liquid and organic transparent polar liquid which are incompatible with each other. According to the organic display device, core display function materials including the packaging liquid, the hydrophobic insulating layer and the pixel wall are all made of organic materials, and selection or design synthesis of the organic materials can be flexibly and accurately regulated and controlled according to performance requirements, so that a wider performance improvement space can be given to the organic display device; and the response speed and the optical performance of the device are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrowetting display, and in particular to an organic display device and a preparation method and application thereof. Background Art

[0002] Electronic paper displays information by reflecting ambient light. It lacks a backlight and self-luminescence, just like paper or books. Therefore, it is a low-power, eye-friendly, and green display technology. Currently, electronic paper is widely used in e-book readers and other fields. Electrowetting is a new type of electronic paper technology. Its basic principle is to use the effect of interfacial charge on interfacial tension to change the contact angle of charged ink droplets, causing the charged ink to contract or expand, thereby achieving an optical switch. However, existing electrowetting displays still suffer from poor controllability, slow response speed, and need for improved optical performance. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an organic display device and a preparation method and application thereof.

[0004] In a first aspect of the present invention, an organic display device is proposed, comprising a first substrate and a second substrate arranged opposite to each other, the first substrate comprising a first support plate and a first electrode layer arranged in sequence along a direction toward the second substrate; the second substrate comprising a second support plate, a second electrode layer, an organic hydrophobic insulating layer and an organic pixel wall arranged in sequence along a direction toward the first substrate, the organic pixel walls forming a pixel grid; a sealed cavity is formed between the first substrate and the second substrate, the sealed cavity being filled with mutually immiscible organic non-polar color-developing liquid and an organic transparent polar liquid.

[0005] According to the embodiment of the present invention, the organic display device has at least the following beneficial effects: the organic display device can use an electric field to control the movement of the organic non-polar color-developing liquid in the pixel grid to achieve reflected light regulation. It is an organic reflective display device, and further an organic reflective electrowetting display device. Specifically, it can be driven by an electric field so that the organic non-polar color-developing liquid in the pixel grid shrinks or spreads on the surface of the organic hydrophobic insulating layer under the promotion of the organic transparent polar fluid, thereby changing the light transmission characteristics and achieving the regulation of reflected light. It has the advantages of faster response speed and easy color realization.

[0006] In this organic display device, the encapsulating liquid filled in the sealed cavity formed between the first substrate and the second substrate is an organic non-polar color-developing liquid and an organic transparent polar liquid that are immiscible with each other, the hydrophobic insulating layer in contact with the encapsulating liquid is an organic hydrophobic insulating layer, and the pixel wall is an organic pixel wall. Therefore, the core display functional materials of the organic display device, including the encapsulating liquid, the hydrophobic insulating layer and the pixel wall, are all organic materials. Since the chemical structure of the organic material can be precisely controlled through molecular design and synthesis to achieve fine control of its performance, this flexibility allows the development of new organic materials with excellent performance according to the application requirements. Therefore, the material selection and design synthesis of the organic non-polar color-developing liquid, the organic transparent polar liquid, the organic hydrophobic insulating layer and the organic pixel wall can be adjusted according to the requirements to obtain an organic display device that meets the requirements. For example, the absorption spectrum of organic non-polar color-developing liquids can be precisely adjusted to achieve higher reflection efficiency and color quality. The structural composition of organic transparent polar liquids and / or organic hydrophobic insulating layer materials can be adjusted to achieve better fluid motion control under electric field drive. And the surface energy of organic pixel wall materials or organic pixel wall surfaces can be precisely controlled to optimize the response speed of organic display devices. Therefore, the flexible controllability of organic material properties and the fully dissolving and uniform rheological properties of organic non-polar display liquids can provide organic display devices with a broader performance improvement space, more reliable anti-electrodeposition stability, and a wider range of applications, thereby improving electric field stability.

[0007] In some embodiments of the present invention, the organic non-polar color-developing liquid is an organic ink material;

[0008] In some embodiments of the present invention, the organic ink material includes an organic dye and a non-polar organic solvent. Specifically, the organic ink material can be prepared by dissolving the organic dye in the non-polar organic solvent.

[0009] In some embodiments of the present invention, the organic dye is selected from at least one of perylene dyes, anthraquinone dyes, phthalocyanine dyes, and azo dyes.

[0010] In some embodiments of the present invention, the organic dye has a conjugated symmetrical molecular structure; further, the organic dye may be an organic dye with a non-polar conjugated symmetrical molecular structure.

[0011] In some embodiments of the present invention, the organic non-polar color-developing liquid may also be made of organic color nanomaterials.

[0012] In some embodiments of the present invention, the organic non-polar color-developing liquid may also be a combination of an organic ink material and an organic color nanomaterial.

[0013] In some embodiments of the present invention, the non-polar organic solvent is selected from non-polar alkane solvents.

[0014] In some embodiments of the present invention, the non-polar organic solvent is selected from at least one of n-decane, n-dodecane, isododecane, and tetradecane.

[0015] In some embodiments of the present invention, the organic transparent polar liquid includes at least one of glycerol, 1,2-propylene glycol, ethylene glycol, an organic ionic liquid, and acetic acid.

[0016] In some embodiments of the present invention, the organic transparent polar liquid further comprises a surfactant.

[0017] The organic hydrophobic insulating layer is made of an organic material, such as a fluororesin. In some embodiments of the present invention, the organic hydrophobic insulating layer is made of an amorphous fluoropolymer, which has a high contact angle with an organic transparent polar liquid and has strong hydrophobicity.

[0018] The organic pixel wall is made of an organic pixel wall material. This material exhibits improved compatibility with other organic materials (including the organic hydrophobic insulating layer), enhancing interfacial bonding, preventing layer delamination, and improving the reliability of the display device. In some embodiments of the present invention, the organic pixel wall is made of a UV-curable polymer or a fluorinated polymer.

[0019] In some embodiments of the present invention, the UV-curable polymer is selected from at least one of acrylate, epoxy resin, polyurethane, photosensitive polyimide, and polydimethylsiloxane (PDMS); the above materials can not only be cured by UV light, but also make the organic pixel wall have a higher density and will not absorb organic non-polar color-developing liquid.

[0020] In some embodiments of the present invention, the fluorinated polymer is selected from at least one of polytetrafluoroethylene (PTFE) and polyfluoroethylene propylene (FEP).

[0021] In some embodiments of the present invention, the material of the first electrode layer and / or the second electrode layer is an organic conductive material.

[0022] In some embodiments of the present invention, the organic conductive material can be selected from at least one of conductive plastics, polyacetylene, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), carbon-based conductive adhesives and other organic conductive materials.

[0023] In some embodiments of the present invention, the first support plate and / or the second support plate is an organic support plate.

[0024] In some embodiments of the present invention, the material of the first support plate and / or the second support plate is selected from at least one of polyimide (PI), polyester (PET), polyetheretherketone (PEEK), and polydimethylsiloxane (PDMS).

[0025] In some embodiments of the present invention, the second substrate further includes an organic dielectric layer, and the organic dielectric layer is disposed between the second support plate and the second electrode layer.

[0026] In some embodiments of the present invention, the material of the organic dielectric layer is selected from at least one of polysiloxane, epoxy resin, acrylate polymer, polyimide (PI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polyethylene terephthalate (PET).

[0027] In some embodiments of the present invention, the organic display device further includes an organic sealant frame, and the organic sealant frame is disposed between the first substrate and the second substrate.

[0028] In some embodiments of the present invention, the organic display device further includes a power supply component, and the power supply component is electrically connected to the first electrode layer and the second electrode layer respectively.

[0029] A second aspect of the present invention provides a method for preparing any of the aforementioned organic display devices of the present invention, comprising:

[0030] preparing a first substrate, including preparing a first electrode layer on a first support plate;

[0031] Preparing a second substrate, including sequentially preparing a second electrode layer, an organic hydrophobic insulating layer, and organic pixel walls on a second support plate, wherein the organic pixel walls form a pixel grid;

[0032] The pixel cells are filled with an organic non-polar color developing liquid, and then filled with an organic transparent polar liquid, and then the first substrate and the second substrate are packaged.

[0033] In some embodiments of the present invention, before filling the pixel cells with the organic non-polar color-developing liquid, the process further includes selecting or preparing an organic non-polar color-developing liquid having a light absorption band that matches the color development requirements of the organic display device.

[0034] In some embodiments of the present invention, the organic pixel wall material is chemically modified before fabrication, and / or the surface of the organic pixel wall is chemically modified after fabrication; the chemical modification treatment is at least one of fluorination and plasma treatment. By chemically modifying the organic pixel wall or its material, the surface energy of the organic pixel wall can be controlled, thereby optimizing the electrowetting response speed.

[0035] In some embodiments of the present invention, after the first electrode layer is prepared and before the organic hydrophobic insulating layer is prepared, an organic dielectric layer is first prepared on the surface of the first electrode layer facing away from the first support plate.

[0036] In some embodiments of the present invention, the method for preparing the organic display device further comprises preparing an organic sealant frame on the organic hydrophobic insulating layer, wherein the organic sealant frame and the organic pixel wall are made of the same material and are prepared simultaneously.

[0037] In some embodiments of the present invention, the materials of the organic sealant frame and the organic pixel wall can both be ultraviolet light-curing polymers; in the preparation process of the organic display device, after the organic hydrophobic insulating layer is prepared, the ultraviolet light-curing polymer can be first coated on the surface of the organic hydrophobic insulating layer, and after heating and curing, it is exposed to ultraviolet light using a mask, and then developed to obtain the organic pixel wall and the organic sealant frame.

[0038] The third aspect of the present invention provides an application of the aforementioned organic display device of the present invention or an organic display device prepared by the aforementioned method of preparing an organic display device of the present invention in the field of electrowetting display, electronic paper, LED or LCD display technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0040] Figure 1 Schematic diagram of the structure of an organic display device according to an embodiment of the present invention;

[0041] Figure 2 for Figure 1 The switching effect diagram of the organic display device shown;

[0042] Figure 3 1 is a comparison diagram of capacitance-voltage curves of the display devices of Example 1 and Comparative Example 1;

[0043] Figure 4 1 is a comparison chart of the opening and closing response times of the display devices of Example 1 and Comparative Example 1;

[0044] Figure 5 This is a comparison diagram of leakage current of the display device of Example 1 and Comparative Example 1 at different voltages;

[0045] Figure 6 This is a comparison chart of the aperture ratios of the display devices of Example 1 and Comparative Example 1 at different voltages. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0047] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0048] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0049] In the description of the present invention, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0050] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0051] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0052] The present invention provides an organic display device, see Figure 1 , Figure 1FIG. 1 shows a schematic structural diagram of an organic display device according to an embodiment of the present invention. Figure 1 As shown, the organic display device includes a first substrate 10, a second substrate 20 and an organic sealing frame 30. The first substrate 10 and the second substrate 20 are arranged opposite to each other and are sealed by the organic sealing frame 30 to form a sealed cavity; the sealed cavity is filled with a packaging liquid, which includes an organic non-polar color-developing liquid 41 and an organic transparent polar liquid 42 that are immiscible with each other.

[0053] The first substrate 10 includes a first support plate 11 and a first electrode layer 12, which are arranged in sequence toward the second substrate 20. The second substrate 20 includes a second support plate 21, a second electrode layer 22, an organic hydrophobic insulating layer 24, and organic pixel walls 25, which are arranged in sequence toward the first substrate 10. The organic pixel walls 25 form a pixel grid, and the organic non-polar color-developing liquid 41 is filled in the pixel grid.

[0054] The first support plate 11 and the second support plate 21 can be transparent support plates, and further, flexible transparent support plates or organic transparent support plates can be used; further, the first support plate 11 and the second support plate 21 can be organic flexible transparent support plates. For example, the materials of the first support plate 11 and the second support plate 21 may include but are not limited to polyimide (PI), polyester (PET), polyetheretherketone (PEEK), polydimethylsiloxane (PDMS), etc. The above-mentioned first support plate 11 and the second support plate 21 use organic flexible transparent support plates, which can improve the device's drop resistance and impact resistance, reduce the risk of display device breakage, and enhance device reliability; at the same time, it can reduce the device weight and improve portability; and based on the flexibility of the organic flexible transparent support plate, it can support curved and irregular shape designs, meet customized needs, and expand the application scenarios of display devices. The first support plate 11 and the second support plate 21 are parallel to each other and arranged opposite each other. The thickness of the two can be set according to actual conditions and is not limited here. In addition, the first support plate 11 and the second support plate 21 can be the same or different.

[0055] The first electrode layer 12 and the second electrode layer 22 are made of a conductive material. A positive electric field or a negative electric field can be generated by applying a voltage between the first electrode layer 12 and the second electrode layer 22 through a power supply component. In some embodiments, the first electrode layer and the second electrode layer are transparent conductive layers, such as ITO layers.

[0056] In some embodiments, the first electrode layer 12 and the second electrode layer 22 can be organic electrode layers, specifically made of an organic conductive material. Furthermore, the first electrode layer 12 and the second electrode layer 22 can be designed as organic transparent electrode layers. The material of the first electrode layer 12 and the second electrode layer 22 can be independently selected from at least one of organic conductive materials such as conductive plastic, polyacetylene, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS), and carbon-based conductive adhesive.

[0057] In this way, the first electrode layer 12 and the second electrode layer 22 adopt organic electrode layers. The organic electrode layers have good flexibility and bendability, can withstand repeated bending, support special-shaped electrodes or device designs, and thus expand the application scenarios of display devices; and the organic electrode layers can usually be prepared at a low temperature of less than 150°C, which can avoid damage to the organic support plate by high temperature; at the same time, the use of organic electrode layers can match the lightweight and thin design of the device, which is conducive to reducing the weight of the device and improving portability; in addition, the surface roughness of the organic electrode layer is low, and organic conductive materials such as PEDOT:PSS also have high light transmittance, which can reduce scattering, improve display contrast, and optimize the optical performance of the device.

[0058] The thickness of the first electrode layer 12 and the second electrode layer 22 can be set according to actual needs and is not limited here.

[0059] The organic hydrophobic insulating layer 24 is made of organic hydrophobic insulating material, which may include but is not limited to amorphous fluoropolymers. Amorphous fluoropolymers have a high contact angle with the organic transparent polar liquid 42 and are highly hydrophobic. The setting of the organic hydrophobic insulating layer 24 can effectively ensure that the organic non-polar color-developing liquid 41 is not easily adhered to the organic hydrophobic insulating layer 24 during the contraction and movement process, thereby ensuring that the organic display device has a better bright display.

[0060] Of course, the material of the organic hydrophobic insulating layer 24 can also be other organic hydrophobic insulating materials. The specific selection, adjustment, and even design and synthesis can be carried out according to actual needs to achieve precise control of its properties and thus optimize device performance. For example, by adjusting the structural composition of the organic hydrophobic insulating layer 24 material, better control of fluid movement under electric field drive can be achieved, thereby improving device performance.

[0061] In this embodiment, an organic dielectric layer 23 is further provided between the second electrode layer 22 and the organic hydrophobic insulating layer 24. The organic dielectric layer 23 may be made of an organic dielectric material. Organic dielectric materials have good ion barrier properties, a high dielectric constant, good film-forming properties, and good adhesion, thereby improving the device's withstand voltage capability. The material of the organic dielectric layer 23 may include, but is not limited to, polysiloxane, epoxy resin, acrylic polymer (such as polymethyl methacrylate (PMMA), polyimide (PI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), and the like. The organic dielectric layer 23 is used, which has a better ion barrier effect than inorganic dielectric layers such as SiN and SiO2, and the raw material price is low. The film layer can be prepared through a printing process, which greatly reduces the preparation cost; and the density of organic dielectric materials is usually lower, which can reduce the weight of the device; in addition, the organic dielectric layer 23 has excellent flexibility and bending resistance, and its thermal expansion coefficient is similar to that of the organic support plate, which can reduce interlayer delamination caused by interface stress and improve the mechanical properties and reliability of the device.

[0062] The thickness of the organic hydrophobic insulating layer 24 and the organic dielectric layer 23 may also be determined according to actual conditions, and the present invention does not limit this.

[0063] The pixel wall in the organic color display device of the present invention adopts an organic pixel wall 25, which is specifically made of organic pixel wall materials. The organic pixel wall 25 has high compatibility and can improve the reliability of the display device; it also has excellent flexibility and bending resistance, and can be processed and prepared by a solution method (including spin coating, inkjet printing) or a photolithography process at a low temperature of less than 200°C, which can avoid damage to the organic hydrophobic insulating layer 24 caused by high temperature; and organic polymers usually have lower density, and some materials (such as photosensitive polyimide PI) have high light transmittance, which is conducive to achieving lightweight devices and optimizing device optical performance; in addition, the pixel wall is constructed with organic materials, and its surface wettability can be controlled. Specifically, the surface energy can be precisely controlled by chemically modifying organic materials such as fluorination treatment and plasma modification to achieve superhydrophobicity (such as a contact angle greater than 150°) or gradient wettability, optimize the electrowetting response speed, and improve device performance.

[0064] Furthermore, the material of the organic pixel wall 25 may be a UV-curable polymer or a fluorinated polymer. Among them, the fluorinated polymer may be selected from at least one of polytetrafluoroethylene (PTFE) and polyperfluoroethylene propylene (FEP), and the above materials can be used to construct a super-hydrophobic surface to reduce liquid adhesion. Using UV-curable polymers, the pixel wall structure can be prepared by photolithography, which is conducive to forming a high-precision pixel wall pattern and can be suitable for building high-resolution display devices. The UV-curable polymer can be selected from at least one of acrylate, epoxy resin, polyurethane, photosensitive polyimide, and polydimethylsiloxane (PDMS); the above materials can not only be cured by UV light, but also make the organic pixel wall 25 have a higher density and will not absorb organic non-polar color-developing liquids; and PDMS has high elasticity and hydrophobicity, which is conducive to improving the mechanical properties of the device.

[0065] The first substrate 10 and the second substrate 20 are connected on all sides by an organic sealant frame 30. The height of the organic sealant frame 30 is generally required to ensure that the first substrate 10 and the second substrate 20 are completely parallel to each other to avoid affecting the display effect of the device. The organic sealant frame 30 can be made of a UV-curable polymer (such as UV photosensitive adhesive) and / or a pressure-sensitive adhesive, such as a UV acrylate pressure-sensitive adhesive.

[0066] The sealed cavity formed by the organic sealant frame 30, the first substrate 11, and the second substrate 20 is filled with mutually immiscible polar liquid and non-polar color-developing liquid. The non-polar color-developing liquid is an organic non-polar color-developing liquid 41, and the polar liquid is an organic transparent polar liquid 42. The use of the organic non-polar color-developing liquid 41 allows the light absorption band of the organic non-polar color-developing liquid to be precisely controlled by designing the organic non-polar color-developing molecular structure, thereby better matching the color-developing requirements of the display device, enabling the device to achieve higher reflection efficiency and color quality, and improving device performance. The use of the organic transparent polar liquid 42 allows its structural components to be adjusted according to actual needs during the device preparation process to finely control the properties of the organic transparent polar liquid to meet device requirements and optimize device performance, such as achieving better fluid motion control effects under electric field drive.

[0067] The organic non-polar color-developing liquid 41 can be made of at least one of an organic ink material and an organic color nanomaterial. In some embodiments, the organic non-polar color-developing liquid 41 is made of an organic ink material, which can include an organic dye and a non-polar organic solvent. Specifically, the organic ink material can be prepared by dissolving the organic dye in the non-polar organic solvent. During the organic ink material preparation process, the light absorption band of the organic ink material can be precisely controlled by selecting the organic dye or designing the molecular structure to better match the color rendering requirements of the color-developing device. Furthermore, by adjusting the material and composition of the non-polar organic solvent, the organic ink material can be manipulated to meet various requirements, such as phase transition temperature, miscibility, and interfacial contact angle.

[0068] The organic dye in the organic ink material may include, but is not limited to, at least one of perylene dyes, anthraquinone dyes, phthalocyanine dyes, and azo dyes. In some embodiments, the organic dye may have a conjugated symmetrical molecular structure, and further, an organic dye with a non-polar conjugated symmetrical molecular structure may be used. Organic dyes with conjugated symmetrical molecular structures have high absorbance, excellent stability, and interfacial compatibility, significantly improving the color performance, response speed, and reliability of organic display devices. Specifically, organic dyes with a conjugated symmetrical molecular structure have high light absorbance, which can reduce the amount of dye used to achieve the ideal color depth; and their symmetrical molecular structure can reduce light scattering, improve color purity and contrast; their conjugated symmetrical structure makes the dye molecule absorption peak sharper, which can reduce spectral overlap and avoid mixing problems; they have high thermal stability and chemical stability, can resist electric field-induced oxidation reactions during electrowetting, extend device life, and at the same time reduce molecular stress, reduce the photolysis rate under ultraviolet or blue light irradiation, and avoid color decay after long-term use; and they have good compatibility with non-polar organic solvents such as alkanes, which can avoid dye aggregation and maintain uniform dispersion; in addition, the symmetrical structure can reduce intermolecular dipole effects and reduce the viscosity of organic non-polar color-developing liquids, thereby improving the electrowetting response speed; furthermore, the symmetrical molecules are more orderly arranged at the oil / water interface, which can reduce interfacial tension, promote the rapid contraction and expansion of organic non-polar color-developing liquids driven by electrowetting, and improve pixel switching efficiency.

[0069] The solvent in the organic ink material is a non-polar organic solvent, specifically a non-polar alkane solvent, for example, at least one selected from n-decane, n-dodecane, isododecane, and tetradecane; of course, in addition to these, other non-polar organic solvents can also be used.

[0070] Since there are a large number of small-volume charged particles in the inorganic polar fluid, they are more likely to be trapped in and penetrate the organic hydrophobic insulating layer under the action of the electric field, causing device failure; at the same time, small-volume charged particles will cause significant electric field drive asymmetry, causing the device to flicker when AC driven. To this end, the polar liquid in the encapsulation liquid of the organic display device of the present invention adopts an organic transparent polar liquid 42. Compared with the aqueous inorganic polar liquid, the volume of the charged ions is larger. Under the action of the electric field, it can effectively improve the ion penetration of the functional layer, prevent electrode corrosion and film peeling caused by fluid penetration, thereby improving the reliability of the device; at the same time, the organic transparent polar liquid 42 will improve the charge trapping phenomenon of the organic hydrophobic insulating layer 24, and the volume and movement speed of its positive and negative charged particles are relatively consistent. Under the electric field drive of different polarities, the response behavior is consistent, which is conducive to improving the symmetry of AC electric field drive, thereby solving the above-mentioned device failure and AC drive asymmetry problems.

[0071] The organic transparent polar liquid 42 may specifically include, but is not limited to, at least one of glycerol, 1.2-propylene glycol, ethylene glycol, an organic ionic liquid, and acetic acid. Furthermore, a surfactant may be added to the organic transparent polar liquid 42 as needed.

[0072] In some embodiments, the organic display device may further include a power supply component, which is electrically connected to the first electrode layer 12 and the second electrode layer 22, and is configured to at least supply power between the first electrode layer 12 and the second electrode layer 22. Of course, in some embodiments, the power supply component may be omitted and an external power supply may be used during use.

[0073] See also Figure 2 ,above Figure 1 In the organic display device shown, when no voltage is applied between the first electrode layer 12 and the second electrode layer 22, no electric field is generated between the two electrode layers. At this time, the organic non-polar color-developing liquid 41 spreads and evenly covers the surface of the organic hydrophobic insulating layer 24 in each pixel grid, and the pixel unit presents a completely dark state of the color of the organic non-polar color-developing liquid 41, that is, the pixel unit is in the off state, as shown in FIG. Figure 2 As shown in (a); when a voltage is applied between the first electrode layer 12 and the second electrode layer 22 by the power supply component, the organic non-polar color-developing liquid 41 moves and shrinks toward the organic pixel wall 25 under the action of the electric field of the two electrode layers, and the organic transparent polar liquid 42 gathers in the pixel grid like the organic non-polar color-developing liquid 41 area at the bottom of the organic pixel wall 25, causing the organic non-polar color-developing liquid 41 to break. At this time, the pixel unit is in a state of reflecting the color of the second substrate 20, that is, the pixel unit is in an open state, as shown in FIG. Figure 2 As shown in (b).

[0074] The present invention also provides a method for preparing the above-mentioned organic display device, comprising the following steps:

[0075] (1) Preparing a first substrate 10 , including preparing a first electrode layer 12 on a first support plate 11 .

[0076] Among them, electrode film forming technology is widely used in industrial production and will not be elaborated here.

[0077] Before forming the first electrode layer 12 on the first support plate 11, the first support plate 11 may be cleaned to remove organic and inorganic impurities on the first support plate 11. For example, the first support plate 11 may be wiped with water and then ethanol, then ultrasonically treated in an ultrasonic cleaning machine, and then blown dry with nitrogen.

[0078] (2) Preparing the second substrate 20 , including sequentially preparing a second electrode layer 22 , an organic hydrophobic insulating layer 24 and organic pixel walls on a second support plate 21 , wherein the organic pixel walls form a pixel grid.

[0079] Specifically, the second electrode layer 22 can be prepared on the second support plate 21 by existing means, which is not limited. Before preparing the second electrode layer 22 on the second support plate 21, the second support plate 22 can also be cleaned to remove organic and inorganic impurities.

[0080] The organic hydrophobic insulating layer 24 can be prepared by coating an organic hydrophobic insulating material solution on the surface of the second electrode layer 22 away from the second support plate 21 by spin coating, dip coating, screen printing, flexible printing, etc., and then curing it in a high temperature environment.

[0081] In addition, before preparing the organic hydrophobic insulating layer 24, an organic dielectric layer 23 can be prepared on the surface of the second electrode layer 22 away from the second support plate 21 to enhance the voltage resistance of the device. The preparation of the organic dielectric layer 23 can be carried out by different preparation methods selected according to the different material properties. For example, for solvent-based materials such as polyimide, spin coating, screen printing, inkjet printing and other methods can be used to form a film, and baking and curing processes are performed after film formation, while solid-state materials such as polytetrafluoroethylene can be formed into a film by spraying or target sputtering. Among them, if a solvent-based organic dielectric material is used to prepare the organic dielectric layer by a solution method (such as spin coating or inkjet printing), the preparation of the organic dielectric layer can be completed at low temperature, which can avoid damage to the organic support plate caused by high temperature.

[0082] Organic pixel walls can be prepared using organic pixel wall materials, such as UV-curable polymers such as acrylates and epoxy resins. During the preparation process, the UV-curable polymer can first be coated on the surface of the organic hydrophobic insulating layer 24 using methods including, but not limited to, slit coating, spin coating, roller coating, doctor blade coating, screen printing, and flexographic printing. The layer is then cured by heating, and a mask is placed over the UV-curable polymer coating. UV light is then exposed to form a pixel wall pattern. Finally, excess UV-curable polymer is removed by development and dissolution, followed by post-baking to form the organic pixel wall 25, which forms a pixel grid.

[0083] In some embodiments, before preparing the organic pixel wall 25, the organic pixel wall material may be subjected to a chemical modification treatment such as fluorination or plasma modification. This chemical modification of the organic pixel wall material can be used to control its performance, thereby controlling the surface energy of the organic pixel wall 25 constructed therefrom, and thereby optimizing the electrowetting response speed. Alternatively, in some embodiments, after the organic pixel wall 25 is prepared, the surface of the organic pixel wall 25 may be subjected to a chemical modification treatment such as fluorination or plasma modification to control its surface energy and optimize the electrowetting response speed.

[0084] Furthermore, before forming the organic pixel walls 25 on the organic hydrophobic insulating layer 24, the organic hydrophobic insulating layer 24 can be hydrophilically modified to improve its surface wettability and make it more hydrophilic, facilitating the subsequent fabrication of the organic pixel walls 25. Furthermore, after the organic pixel walls 25 are fabricated, the substrate with the organic pixel walls can be subjected to a high-temperature treatment to restore the hydrophobicity of the organic insulating layer. The hydrophilic modification can be achieved by plasma etching, and the high-temperature treatment temperature generally needs to exceed the Tg temperature of the organic hydrophobic insulating layer 24.

[0085] The preparation order of the first substrate 10 and the second substrate 20 is not limited and can be adjusted according to actual needs during the production process.

[0086] (4) An organic sealant frame 30 is provided on the circumferential edge of the organic hydrophobic insulating layer 24 on the second substrate 20 to form a receiving space. The organic sealant frame 30 may be made of a UV-curable polymer (e.g., UV photosensitive adhesive) and / or a pressure-sensitive adhesive. At least one opening is reserved in the organic sealant frame 30 to allow excess organic transparent polar liquid 42 to flow out during the packaging process.

[0087] In some embodiments, the organic sealant frame material can be first patterned on the circumferential edge surface of the organic hydrophobic insulating layer 24 by screen printing, and then cured to obtain the organic sealant frame 30; in other embodiments, the material of the organic sealant frame 30 can be a UV-curable polymer. During preparation, the organic sealant frame material can be first coated on the circumferential edge surface of the organic hydrophobic insulating layer 24 by slit coating, spin coating, roller coating, scraping or flexible printing, and then the organic sealant frame 30 can be obtained by photolithography and development technology.

[0088] The order in which the organic sealant frame 30 and the organic pixel wall 25 are arranged is not limited and can be adjusted according to actual needs during the production process. For example, the organic pixel wall 25 can be arranged first, and the organic sealant frame 30 can be arranged later; or the organic sealant frame 30 can be arranged first, and the organic pixel wall 25 can be arranged later. In some embodiments, the organic pixel wall 25 and the organic sealant frame 30 can be arranged at the same time. For example, the organic pixel wall 25 and the organic sealant frame 30 can be made of the same material (such as a UV-curable polymer). Then, the organic pixel wall 25 and the organic sealant frame 30 can be constructed simultaneously through photolithography and development processes. That is, the organic pixel wall 25 and the organic sealant frame 30 can be obtained simultaneously through a single process, thereby simplifying the process and improving production efficiency.

[0089] (5) The pixel grids formed by the organic pixel walls 25 on the second substrate 20 are filled with an organic non-polar color-developing liquid 41, and then the accommodating space formed by the organic sealing frame 30 is filled with an organic transparent polar liquid 42. The organic transparent polar liquid 42 covers the organic non-polar color-developing liquid 41 and the organic pixel walls 25.

[0090] (6) Cover the first substrate 10 on top of the second substrate 20, and set the first electrode layer 11 of the first substrate 10 toward the second substrate 20; keep the first substrate 10 and the second substrate 20 horizontal, and then apply pressure to the first substrate 10, specifically, first apply greater pressure to the central area of the first substrate 10. Due to uneven force, the central area of the first substrate 10 will first contact the organic transparent polar liquid 42, and then apply less pressure to the circumferential area of the first substrate 10. The first substrate 10 is less deformed, and the contact area with the organic transparent polar liquid 42 is increased. The excess organic transparent polar liquid 42 flows out from the opening of the organic sealant frame 30. After the first substrate 10 is completely in contact with the organic transparent polar liquid 42, the opening can be sealed with a packaging material such as ultraviolet acrylate, and finally pressed and dried to complete the packaging of the entire organic display device.

[0091] During the research process, the inventors conducted a large number of research experiments, including experimental studies to investigate the impact of the polar liquid selected in the encapsulation liquid on the performance of the display device. Specifically, different display devices were constructed using organic transparent polar liquids and water as polar liquids for the encapsulation liquid, and their performance was tested and compared. The method for preparing the display device specifically includes:

[0092] S1. Preparing electrode layers on the surfaces of two support plates, comprising: taking two pieces of conductive glass as support plates, wiping them with clean water and 90% ethanol in sequence, placing them in an ultrasonic cleaner for ultrasonic treatment to remove organic and inorganic impurities on the support plates, blowing them dry with nitrogen, and then preparing an ITO layer on the surfaces;

[0093] S2. Preparing an organic dielectric layer on one of the support plates having an ITO electrode layer, comprising: using an acrylate-based polymerizable monomer as a raw material, spin-coating the monomer onto the surface of the ITO electrode layer facing away from the support plate, and curing the resulting organic dielectric layer to a thickness of 400 nm;

[0094] S3. Preparing an organic hydrophobic insulating layer on the organic dielectric layer, including: using a fluororesin material as a raw material, spin-coating it on the surface of the organic dielectric layer away from the ITO electrode layer, baking and curing it after film formation to obtain an organic hydrophobic insulating layer; and then performing plasma etching on the organic hydrophobic insulating layer to change the organic hydrophobic insulating layer from hydrophobic to hydrophilic, thereby obtaining a hydrophilic organic insulating layer.

[0095] S4. Preparing an organic pixel wall and an organic sealant frame on the organic hydrophobic insulating layer, comprising: spin-coating an acrylate-based photoresist material on the surface of the organic hydrophobic insulating layer facing away from the organic dielectric layer, heating and curing, covering the coating surface with a mask, and then exposing and developing the organic pixel wall and the organic sealant frame. The organic pixel wall forms a pixel grid, and the organic sealant frame is arranged at the circumferential edge of the organic hydrophobic insulation to form an accommodating space. Four openings are reserved on the organic sealant frame, and the four openings are arranged around the organic sealant frame to allow excess polar liquid to flow out through the openings during the packaging process. After completing the preparation of the organic pixel wall and the organic sealant frame, the substrate on which the pixel wall and the organic sealant frame are prepared is subjected to high-temperature treatment at a high temperature exceeding the Tg temperature of the organic hydrophobic insulating layer to restore the hydrophobicity of the organic insulating layer.

[0096] S5. Filling the packaging liquid includes: filling the pixel grid with an organic non-polar color-developing liquid obtained by dissolving an organic dye in n-decane, and then filling the accommodating space formed by the organic sealant frame with a polar liquid, wherein the polar liquid covers the organic non-polar color-developing liquid and the pixel wall.

[0097] S6. Packaging, including: covering another support plate provided with an electrode layer on top of the support plate filled with packaging liquid, with the electrode layer setting sides of the two support plates arranged opposite to each other, and the two support plates kept horizontally placed, and then applying pressure to the upper support plate, specifically first applying greater pressure to the central area of the support plate, the central area of the upper support plate first contacts the polar liquid, and then applying less pressure to the circumferential area of the upper support plate, the deformation of the upper support plate is smaller, the contact area with the polar liquid is increased, and excess polar liquid flows out from the opening of the organic sealant frame, and after the upper support plate is completely in contact with the polar liquid, the opening is sealed with the packaging glue material UV acrylate, and finally pressed and dried to complete the preparation of the display device.

[0098] According to the above preparation method, display devices were prepared using organic transparent polar liquid propylene glycol and water as the polar liquid in the encapsulating liquid, respectively. The display device filled with organic transparent polar liquid propylene glycol was used as Example 1, and the display device filled with water was used as Comparative Example 1. Then, the display devices of Example 1 and Comparative Example 1 were subjected to electrical performance tests and optical performance tests, respectively. The electrical performance tests included capacitance-voltage curve tests, leakage current-voltage tests, and response time tests; the optical performance tests included aperture ratio-voltage curve tests. The results are shown in FIG. Figures 3 to 6 shown.

[0099] Depend on Figure 3 It can be seen that the capacitance value of the display device filled with organic polar fluid is smaller than that of the display device filled with water, and the change in capacitance value with increasing voltage is also smaller than that of the display device filled with water.

[0100] Depend on Figure 4 It can be seen that the response time of the display device filled with organic polar fluid is faster than that of the display device filled with water, both in terms of opening time and closing time. Therefore, the response speed is faster than that of the display device filled with water.

[0101] Depend on Figure 5 It can be seen that the leakage current value of the display device filled with organic polar fluid is smaller than that of the display device filled with water, and changes less with the increase of voltage.

[0102] Depend on Figure 6 It can be seen that display devices filled with organic polar fluids have lower opening voltages, enabling lower voltage drive, more precise voltage control, and thus higher grayscale. A comparison also shows that, at the same voltage, the aperture ratio of display devices filled with organic polar fluids is greater than that of display devices filled with water.

[0103] As described above, the core display functional materials of the organic liquid crystal display device of the present invention, including the encapsulation liquid, the hydrophobic insulating layer and the pixel wall, are all made of organic materials. Since the chemical structure of the organic material can be precisely controlled through molecular design and synthesis, its performance can be finely controlled. This flexibility allows the organic material to develop new materials with excellent performance according to the application requirements, and then the material selection or design synthesis including the organic non-polar color-developing liquid, the organic transparent polar liquid, the organic hydrophobic insulating layer and the organic pixel wall can be flexibly and precisely controlled according to the requirements to obtain an organic display device that meets the requirements. Among them, the flexible controllability of the organic material performance and the fully dissolving uniform rheological properties can give the organic display device a broader performance improvement space, more reliable anti-electrodeposition stability and application range. The organic display device can be applied to technical fields such as electrowetting display, electronic paper, LED or LCD display.

[0104] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. An organic display device, characterized in that: It includes a first substrate and a second substrate arranged opposite to each other, the first substrate includes a first support plate and a first electrode layer arranged in sequence along the direction toward the second substrate; the second substrate includes a second support plate, a second electrode layer, an organic hydrophobic insulating layer and an organic pixel wall arranged in sequence along the direction toward the first substrate, and the organic pixel wall forms a pixel grid; a sealed cavity is formed between the first substrate and the second substrate, and the sealed cavity is filled with an organic non-polar color-developing liquid and an organic transparent polar liquid that are immiscible with each other.

2. The organic display device according to claim 1, wherein The organic non-polar color-developing liquid is an organic ink material.

3. The organic display device according to claim 2, wherein the organic ink material comprises an organic dye and a non-polar organic solvent; Preferably, the organic dye has a conjugated symmetrical molecular structure, and / or the non-polar organic solvent is selected from non-polar alkane solvents.

4. The organic display device according to claim 1, wherein The organic transparent polar liquid includes at least one of glycerol, 1,2-propylene glycol, ethylene glycol, an organic ionic liquid, and acetic acid; Preferably, the organic transparent polar liquid further comprises a surfactant.

5. The organic display device according to claim 1, wherein The material of the organic hydrophobic insulating layer is selected from amorphous fluoropolymer; and / or the material of the organic pixel wall is selected from ultraviolet curable polymer or fluorinated polymer.

6. The organic display device according to claim 1, wherein The material of the first electrode layer and / or the second electrode layer is an organic conductive material; Preferably, the organic conductive material is selected from at least one of conductive plastics, polyacetylene, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, and carbon-based conductive adhesive.

7. The organic display device according to claim 1, wherein The second substrate further includes an organic dielectric layer, and the organic dielectric layer is provided between the second support plate and the second electrode layer; Preferably, the material of the organic dielectric layer is selected from at least one of polysiloxane, epoxy resin, acrylic polymer, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, and polyethylene terephthalate.

8. The organic display device according to any one of claims 1 to 7, characterized in that The organic display device further includes an organic sealant frame, and the organic sealant frame is provided between the first substrate and the second substrate; And / or, the organic display device further includes a power supply component, and the power supply component is electrically connected to the first electrode layer and the second electrode layer respectively.

9. The method for preparing an organic display device according to any one of claims 1 to 8, characterized in that: The following steps are involved: preparing a first substrate, including preparing a first electrode layer on a first support plate; Preparing a second substrate, including sequentially preparing a second electrode layer, an organic hydrophobic insulating layer, and organic pixel walls on a second support plate, wherein the organic pixel walls form a pixel grid; The pixel cells are filled with an organic non-polar color developing liquid, and then filled with an organic transparent polar liquid, and then the first substrate and the second substrate are packaged.

10. Use of the organic display device according to any one of claims 1 to 8 or the organic display device produced by the method for producing the organic display device according to claim 9 in the field of electrowetting display, electronic paper, LED or LCD display technology.

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