Fluorescent electrophoretic ink and display device

Abstract

The invention discloses fluorescent electrophoretic ink and a display device, and relates to the technical field of electrophoretic display. The fluorescent electrophoretic ink comprises an electrophoretic medium, and first electrophoretic particles, second electrophoretic particles and third electrophoretic particles dispersed in the electrophoretic medium; the first electrophoretic particle has a first charge polarity, the second electrophoretic particle has a second charge polarity, and the third electrophoretic particle has the first charge polarity or the second charge polarity; the first electrophoretic particles present a first color under visible light irradiation, and the second electrophoretic particles present a second color under visible light irradiation; and the third electrophoretic particles are in a colorless transparent state or a semitransparent state under the irradiation of visible light, and are in fluorescence emission of a third color under the irradiation of invisible light with a preset wavelength. The display effect of fluorescent electrophoresis display is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrophoretic display, and in particular to a fluorescent electrophoretic ink and a display device. Background Art

[0002] Traditional electrophoretic display devices can usually only be used under white light, showing black and white colors, such as sunlight and white light, and have a certain dependence on light sources. In order to increase the application scenarios of electrophoretic display devices, fluorescent electrophoretic particles are introduced to enable them to emit light under non-visible light (infrared light, ultraviolet light, etc.), so that they can display fluorescently, which can be expected to be used in fields such as anti-counterfeiting and display.

[0003] In current fluorescent electrophoretic displays, fluorescent electrophoretic particles are usually used to replace one of the two-color electrophoretic particles. Fluorescent electrophoretic particles play both reflective and fluorescent roles, but the optical reflective performance of fluorescent electrophoretic particles is very poor, and the display effect of the device under visible light source is very poor. The color difference between the fluorescent state and the reflective state and between the excitation light source and the fluorescent state of the device is not significant and will not directly affect the display effect of the device. Summary of the invention

[0004] The embodiments of the present invention provide a fluorescent electrophoretic ink and a display device, aiming to improve the display effect of fluorescent electrophoretic display.

[0005] The fluorescent electrophoretic ink proposed by the present invention comprises an electrophoretic medium and first electrophoretic particles and second electrophoretic particles dispersed in the electrophoretic medium, wherein the first electrophoretic particles have a first charge polarity and present a first color under visible light irradiation, and the second electrophoretic particles have a second charge polarity and present a second color under visible light irradiation;

[0006] Characterized in that the fluorescent electrophoretic ink further comprises third electrophoretic particles dispersed in the electrophoretic medium;

[0007] The third electrophoretic particle has a first charge polarity or a second charge polarity;

[0008] The third electrophoretic particles are in a colorless transparent state or a semi-transparent state under visible light, and emit fluorescence of a third color under non-visible light of a preset wavelength.

[0009] Optionally, a particle size of the third electrophoretic particle is smaller than a particle size of the first electrophoretic particle and a particle size of the second electrophoretic particle.

[0010] Optionally, the particle size of the third electrophoretic particle is 10-200 nm.

[0011] Optionally, the first color and the second color are different, and the first color and the second color are any two of white, black, red, orange, yellow, green, cyan, blue, purple or other colors.

[0012] Optionally, the third electrophoretic particle includes a fluorescent pigment, and the fluorescent pigment is at least one of an inorganic / organic up-conversion fluorescent pigment, an inorganic / organic ultraviolet down-conversion fluorescent pigment, and a composite fluorescent pigment.

[0013] Optionally, the third electrophoretic particle includes a fluorescent pigment layer and a polymer layer wrapped outside the fluorescent pigment layer.

[0014] Optionally, the fluorescent pigment is an up-conversion fluorescent pigment, and the third electrophoretic particle is prepared by the following steps:

[0015] Step 1, ball-milling the up-conversion fluorescent pigment to a preset particle size;

[0016] Step 2, adding the ball-milled fluorescent pigment, tetraethyl silicate and a silane coupling agent into a polar solvent and stirring to perform a coupling reaction to obtain coupled fluorescent pigment particles;

[0017] Step 3, polymerizing the coupled fluorescent pigment particles with polymer monomers to obtain polymer-coated fluorescent electrophoretic particles.

[0018] Optionally, the third electrophoretic particle includes nanoparticles having hydroxyl groups on the surface, a quantum dot light-emitting layer disposed on the nanoparticles, and a polymer layer wrapped around the quantum dot light-emitting layer.

[0019] Optionally, the third electrophoretic particle is prepared by the following steps:

[0020] Step 1, mixing nanoparticles containing hydroxyl groups on the surface with a silane coupling agent, a non-polar solvent, and acetic acid according to a preset ratio, ball milling, and then dispersing the mixture in a non-polar solvent to obtain a nanoparticle solution;

[0021] Step 2, dropping a perovskite quantum dot precursor solution into the nanoparticle solution, and stirring for a preset time to obtain nanoparticles loaded with perovskite quantum dots;

[0022] Step 3: polymerizing the nanoparticles loaded with perovskite quantum dots with polymer monomers to obtain fluorescent electrophoretic particles coated with polymers.

[0023] The display device provided by the present invention comprises an upper electrode and a lower electrode, wherein the upper electrode and the lower electrode are used to connect the positive and negative electrodes of a power source;

[0024] A receiving cavity is formed between the upper electrode and the lower electrode, and the receiving cavity is filled with the fluorescent electrophoresis ink mentioned above.

[0025] The present invention has the following beneficial effects:

[0026] The present invention introduces a third electrophoretic particle with a small particle size and colorless, transparent or translucent under visible light into a two-color electrophoretic ink including a first electrophoretic particle and a second electrophoretic particle to prepare a fluorescent electrophoretic ink. The third electrophoretic particle does not affect the reflected light display of the first electrophoretic particle and the second electrophoretic particle under visible light irradiation, and can achieve good fluorescent display under non-visible light irradiation. At the same time, the charged third electrophoretic particle with a small particle size can promote the separation of the first electrophoretic particle and the second electrophoretic particle, thereby ensuring the high contrast and fast response speed of the display device under ambient light, and making the fluorescent color distinction more obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 Schematic diagrams of the structures of some embodiments of the display device of the present invention;

[0029] Figure 2 A schematic diagram of the interaction between electrophoretic particles in the fluorescent electrophoretic ink of the present invention;

[0030] Figure 3 Schematic diagrams of the structures of some embodiments of the fluorescent electrophoretic particles of the present invention;

[0031] Figure 4 Schematic diagram of the preparation process of some embodiments of the fluorescent electrophoretic particles of the present invention;

[0032] Figure 5 Schematic diagram of the preparation process of other embodiments of the fluorescent electrophoretic particles of the present invention;

[0033] Figure 6 It is a schematic diagram of the operation of some embodiments of the display device of the present invention;

[0034] Figure 7 for Figure 6 The actual picture of the working status of the display device shown;

[0035] Figure 8 Schematic diagrams of the operation of other embodiments of the display device of the present invention;

[0036] Fig. 9 for Figure 8 The actual picture of the working status of the display device is shown.

[0037] Description of reference numerals:

[0038] 1. Substrate; 21. Upper electrode; 22. Lower electrode; 31. White electrophoretic particles; 32. Black electrophoretic particles; 33. Fluorescent electrophoretic particles. DETAILED DESCRIPTION

[0039] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The English professional terms involved in the present invention are explained as follows:

[0041] UCNP: upconversion nanoparticles; TEOS: tetraethyl orthosilicate; LMA: dodecyl methacrylate; AIBN: azobisisobutyronitrile; span80: span 80; SDBS: sodium dodecylbenzenesulfonate; ABVN: azobisisoheptanenitrile; NaYF4 (Yb 3+ , Er 3+ ):Yb 3+ , Er 3+ Doped NaYF4; DMF: N,N-dimethylformamide.

[0042] In electrophoretic electronic display technology, pigment particles of different colors and different charges are placed in a non-polar solvent. The directional movement of the charged pigment particles is controlled by applying an external voltage to present different colors, thereby realizing the display of patterns.

[0043] Traditional electrophoretic display is mainly black and white, which can no longer meet people's needs. In order to increase the application scenarios of electrophoretic display devices, fluorescent electrophoretic particles are introduced to enable them to emit light under non-visible light (infrared light, ultraviolet light, etc.), so that they can display fluorescently and are widely used in anti-counterfeiting and display fields.

[0044] The inventors of the present application have conducted intensive research and discovered that in current fluorescent electrophoretic displays, fluorescent electrophoretic particles are usually used to replace one of the two-color electrophoretic particles. The fluorescent electrophoretic particles simultaneously play both reflective and fluorescent roles, but the optical reflective performance of the fluorescent electrophoretic particles is very poor, and the display effect of the display device under visible light sources is very poor. The color difference between the fluorescent state and the reflective state, and between the excitation light source and the fluorescent state of the device is not significant, which will directly affect the display effect of the device.

[0045] The present invention provides a fluorescent electrophoretic ink and a display device, aiming to solve the above problems.

[0046] In an embodiment of the present invention, the fluorescent electrophoretic ink includes an electrophoretic medium and first electrophoretic particles, second electrophoretic particles and third electrophoretic particles dispersed in the electrophoretic medium.

[0047] The electrophoretic medium is composed of a transparent non-polar solvent and a charge control agent, the non-polar solvent is selected from one or more of halogenated hydrocarbons, paraffin, silicone oil, alkane compounds, epoxy compounds, aromatic hydrocarbons, and vinyl ethers, and the charge control agent is selected from one or more of organic sulfonates, organic sulfates, organic phosphates, organic phosphate esters, polyesters, polyolefins, and polyacrylate charge control agents.

[0048] The first electrophoretic particle has a first charge polarity, the second electrophoretic particle has a second charge polarity, and the third electrophoretic particle has the first charge polarity or the second charge polarity; and the first electrophoretic particle exhibits a first color under visible light, and the second electrophoretic particle exhibits a second color under visible light; the third electrophoretic particle is colorless under visible light, and exhibits fluorescent light of a third color under non-visible light of a preset wavelength.

[0049] Optionally, the first color and the second color are colors that can form a strong contrast between the first electrophoretic particle and the second electrophoretic particle under visible light, such as any two of white, black, red, orange, yellow, green, cyan, blue, purple or other colors; the first electrophoretic particle and the second electrophoretic particle are dispersed in the electrophoretic medium with opposite charges, and when an external voltage is applied, the first electrophoretic particle and the second electrophoretic particle will move in opposite directions in the electrophoretic medium, and the color corresponding to one of the two electrophoretic particles will be displayed on the light emitting surface or observation side of the display device.

[0050] Alternatively, the first electrophoretic particles and the second electrophoretic particles may be a combination of any two of the following: black positively charged particles, white negatively charged particles, black negatively charged particles, and white positively charged particles, having opposite charge properties and opposite colors.

[0051] In an embodiment of the present invention, the third electrophoretic particle is colorless, transparent or translucent under visible light, and its reflection effect on visible light is zero or very low, that is, under normal observation conditions, it does not show obvious color and will not affect the color presentation of the first electrophoretic particle and the second electrophoretic particle.

[0052] The third electrophoretic particle has the same charge property as the first electrophoretic particle or the second electrophoretic particle. When an external voltage is applied, the first electrophoretic particle or the second electrophoretic particle moves together with the third electrophoretic particle into the electrophoretic medium close to the light emitting surface or the observation side of the display device, and presents the corresponding color of the electrophoretic particle at that location under visible light. Under non-visible light, the third electrophoretic particle fluoresces to present a third color.

[0053] The third electrophoretic particle exhibits fluorescence of a third color under non-visible light, which includes infrared light and ultraviolet light. The third color is white, black, red, orange, yellow, green, cyan, blue, purple or any other color, and is different from the first color and the second color.

[0054] In an embodiment of the present invention, fluorescent electrophoretic particles (i.e., third electrophoretic particles) that are colorless, transparent or translucent under visible light are introduced into a two-color electrophoretic ink including first electrophoretic particles and second electrophoretic particles to produce fluorescent electrophoretic ink. The colorless fluorescent electrophoretic particles do not affect the reflected light display of the first electrophoretic particles and the second electrophoretic particles under visible light, and good fluorescent display can be achieved under non-visible light.

[0055] Optionally, the third electrophoretic particle includes a fluorescent pigment, and the fluorescent pigment is at least one of an inorganic / organic up-conversion fluorescent pigment, an inorganic / organic ultraviolet down-conversion fluorescent pigment, and a composite fluorescent pigment.

[0056] Among them, upconversion fluorescent pigments realize upconversion luminescence, that is, absorbing two or more low-energy photons and radiating one high-energy photon, converting long-wave radiation into short-wave radiation, thereby producing fluorescence phenomenon.

[0057] After the ultraviolet down-conversion fluorescent pigment absorbs ultraviolet light, its internal molecular structure will change, causing the electrons to jump from the ground state to the excited state. When the electrons return to the ground state from the excited state, they release energy and emit it in the form of visible light, thus producing fluorescence.

[0058] Composite fluorescent pigments are fluorescent pigments formed by combining fluorescent substances with inorganic / organic carriers. For example, quantum dots with unique optical properties can be combined with other materials to form pigments with fluorescent properties.

[0059] See also Figure 3 and Figure 4 In some embodiments, the third electrophoretic particle includes a fluorescent pigment layer and a polymer layer wrapped outside the fluorescent pigment layer, the fluorescent pigment layer is used for fluorescent luminescence, and the polymer layer is used for improving the dispersibility of the electrophoretic particle.

[0060] Specifically, tetraethyl silicate and a silane coupling agent can be hydrolyzed with fluorescent pigment particles to form grafting, and the coupled fluorescent pigment can be polymerized with a polymer monomer to obtain fluorescent electrophoretic particles coated with the polymer, which can specifically include the following steps:

[0061] Step 1, ball-milling the fluorescent pigment to a preset particle size;

[0062] Step 2, adding the ball-milled fluorescent pigment, tetraethyl silicate and a silane coupling agent into a polar solvent and stirring to perform a coupling reaction to obtain coupled fluorescent pigment particles;

[0063] Step 3, polymerizing the coupled fluorescent pigment particles with polymer monomers to obtain polymer-coated fluorescent electrophoretic particles.

[0064] See also Figure 5 In some other embodiments, the third electrophoretic particle includes nanoparticles having hydroxyl groups on the surface, a quantum dot light-emitting layer disposed on the nanoparticles, and a polymer layer wrapped around the quantum dot light-emitting layer.

[0065] Nanoparticles containing hydroxyl groups on their surfaces include, but are not limited to, silicon dioxide, zinc oxide, or aluminum oxide nanoparticles.

[0066] Quantum dots are a type of low-dimensional semiconductor material, generally spherical or quasi-spherical, with a diameter usually between 2-20nm. By applying light excitation to this nano-semiconductor material, they will emit fluorescence of a specific frequency. The size of the quantum dots will also affect the color of their luminescence.

[0067] Specifically, after the nanoparticles containing hydroxyl groups on the surface are grafted by a silane coupling agent, the perovskite quantum dot precursor solution is added dropwise to the nanoparticle solution to form nanoparticles loaded with perovskite quantum dots, and then the nanoparticles are polymerized with polymer monomers to obtain fluorescent electrophoretic particles coated with polymers. Specifically, the following steps may be included:

[0068] Step 1, mixing nanoparticles containing hydroxyl groups on the surface with a silane coupling agent, a non-polar solvent, and acetic acid according to a preset ratio, ball milling, and then dispersing the mixture in a non-polar solvent to obtain a nanoparticle solution;

[0069] Step 2, dropping a perovskite quantum dot precursor solution into a nanoparticle solution, and stirring for a preset time to obtain nanoparticles loaded with perovskite quantum dots;

[0070] Step 3, polymerizing the nanoparticles loaded with perovskite quantum dots with polymer monomers to obtain fluorescent electrophoretic particles coated with the polymer.

[0071] Furthermore, in some embodiments, the polymer on the surface of the fluorescent electrophoretic particles can undergo acid-base interactions with some surfactants, causing proton transfer to carry corresponding positive or negative charges; the surfactant can be selected from one or more of organic sulfonates, organic sulfates, organic phosphates, organic phosphate esters, polyesters, polyolefins, and polyacrylates.

[0072] In the embodiments of the present invention, types of silane coupling agents include but are not limited to KH570, KH560, and KH550, and types of polymer monomers include but are not limited to acrylic, epoxy, styrene, alcohol, and anhydride.

[0073] In an embodiment of the present invention, the particle size of the third electrophoretic particle is smaller than the particle size of the first electrophoretic particle and the particle size of the second electrophoretic particle.

[0074] See also Figure 2 In an embodiment of the present invention, the charge of the third electrophoretic particle is less than that of the first electrophoretic particle and the second electrophoretic particle. The third electrophoretic particle with a small particle size and low charge will preferentially adsorb to the particles with opposite charges, thereby promoting the separation of the first electrophoretic particle and the second electrophoretic particle, ensuring the high contrast and fast response speed of the display device under ambient light, and making the fluorescent color distinction more obvious.

[0075] Since the particle size of the electrophoretic particles reflecting visible light used in conventional electrophoretic display is usually above 200 nm, in the embodiment of the present invention, the particle size of the third electrophoretic particles can be selected to be 10-200 nm.

[0076] It can be seen from the above embodiments that the present invention introduces small-sized colorless, transparent or translucent fluorescent electrophoretic particles (i.e., third electrophoretic particles) into a two-color electrophoretic ink including first electrophoretic particles and second electrophoretic particles to form fluorescent electrophoretic ink. The colorless, transparent or translucent fluorescent electrophoretic particles do not affect the reflected light display of the first electrophoretic particles and the second electrophoretic particles under visible light irradiation, and can achieve good fluorescent display under non-visible light irradiation; at the same time, the small-sized charged fluorescent electrophoretic particles can promote the separation of the first electrophoretic particles and the second electrophoretic particles, thereby ensuring the high contrast and fast response speed of the display device under ambient light, and making the fluorescent color distinction more obvious.

[0077] Therefore, the present invention can effectively improve the display effect of the fluorescent electrophoresis display device.

[0078] Based on the above-mentioned embodiment of the fluorescent electrophoretic ink, the present invention further provides a display device.

[0079] See also Figure 1 In some embodiments, the display device proposed in the present invention includes an upper electrode 21 and a lower electrode 22. A substrate 1 is provided on the outer side of the upper electrode 21 and the lower electrode 22 to provide structural support. The upper electrode 21 and the lower electrode 22 are used to connect the positive and negative poles of the power supply. The upper electrode 21 is the light emitting surface / observation side, and the substrate on the outer side of the upper electrode 21 can be made of transparent material; a accommodating cavity is formed between the upper electrode 21 and the lower electrode 22, and the accommodating cavity is filled with the fluorescent electrophoretic ink provided in the above embodiments.

[0080] See also Figure 1In some embodiments, the fluorescent electrophoretic ink injected into the display device includes an electrophoretic medium and white electrophoretic particles 31 , black electrophoretic particles 32 and fluorescent electrophoretic particles 33 dispersed in the electrophoretic medium.

[0081] In the embodiments of the present invention, depending on the substrate and electrode materials, the display device may be a rigid display device based on conductive glass, or a flexible display device such as electronic paper based on a flexible substrate.

[0082] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the following specific embodiments are not limitations of the present invention, and those skilled in the art can make various changes within the scope of the rights of the present invention.

[0083] Example 1

[0084] A longitudinally driven electrophoretic display device based on up-conversion fluorescent electrophoretic particles.

[0085] First, prepare upconversion fluorescent electrophoretic particles. The preparation process is shown in Figure 4 , including the following steps:

[0086] 5g NaYF4 (Yb 3+ , Er 3+ ), 5g TEOS, 10g KH570, 100ml ethanol and 5mL ammonia water were stirred for 4h, and then centrifuged and washed several times to obtain coupled fluorescent electrophoretic particles.

[0087] 5 g of coupled fluorescent electrophoretic particles, 1 g of hexadecyltrimethylammonium bromide, 100 ml of toluene and 10 g of LMA were mechanically stirred at 600 rpm for 1 h at 40 degrees Celsius under a nitrogen atmosphere, and 1 g of AIBN was added and polymerized at 70 degrees Celsius for 12 h to obtain fluorescent electrophoretic particles.

[0088] The preparation of a display device comprises the following steps:

[0089] The two-sided ITO electrodes are bonded with OCA glue to form a simple display device, and fluorescent electrophoretic ink composed of negatively charged white electrophoretic particles, negatively charged fluorescent electrophoretic particles and positively charged black electrophoretic particles is injected to form an electrophoretic display device.

[0090] See also Figure 6When the display device prepared in this embodiment is just filled with fluorescent electrophoretic ink, the device is in a gray state. When a voltage of +15V is applied to the upper electrode, the positive and negative particles are separated, and the negatively charged white particles and the fluorescent electrophoretic particles are driven to the upper electrode together. At this time, the display device is in a white state; when the display device is in a white state, the fluorescent electrophoretic particles can emit green light under the illumination of an external infrared light, making the display device in a green state; and when a negative charge is applied to the upper electrode, the positively charged black electrophoretic particles are driven to the upper electrode, making the display device in a black state; therefore, this embodiment can realize a black, white, and green three-state display of a longitudinally driven electrophoretic display device based on up-conversion fluorescent electrophoretic particles by regulating positive and negative voltages and illuminating with an external infrared light, such as Figure 7 shown.

[0091] Example 2

[0092] A longitudinally driven electrophoretic display device based on silica-loaded quantum dot fluorescent particles.

[0093] First, prepare silica-loaded quantum dot fluorescent particles. The preparation process is shown in Figure 5 , including the following steps:

[0094] 50 g of silica, 20 g of silane coupling agent (KH550+KH570), 200 ml of toluene and 5 ml of acetic acid were ball-milled for 12 h, then centrifuged several times and dispersed in 200 ml of toluene solution to obtain a silica toluene solution.

[0095] 3.15 g of cesium bromide and 5.48 g of lead bromide were dissolved in 100 ml of DMF, and 10 ml of oleic acid and 10 ml of oleylamine were added dropwise to the DMF solution to obtain a precursor solution of perovskite quantum dots.

[0096] 30 ml of the precursor solution of perovskite quantum dots was added dropwise into 200 ml of the silica toluene solution and stirred at 500 rpm for 5 h to obtain SiO2 (SiO2 / CsPbBr3) loaded with perovskite quantum dots.

[0097] 10 g SiO2 / CsPbBr3, 1 g SDBS, 100 ml toluene, 5 g LMA and 1 g ABVN were mechanically stirred and polymerized at 40 degrees Celsius and 600 rpm for 12 hours to obtain fluorescent electrophoretic particles.

[0098] The preparation of a display device comprises the following steps:

[0099] The two-sided ITO electrodes are bonded with OCA glue to form a simple display device, and fluorescent electrophoretic ink composed of negatively charged white electrophoretic particles, positively charged fluorescent electrophoretic particles and positively charged black electrophoretic particles is injected to form an electrophoretic display device.

[0100] See also Figure 8When the display device prepared in this embodiment is just filled with fluorescent electrophoretic ink, the device is in a gray state. When a voltage of -15V is applied to the upper electrode, the positive and negative particles are separated, and the positive black particles and the fluorescent electrophoretic particles are driven to the upper electrode together, and the display device is in a black state. When the display device is in a black state, the fluorescent electrophoretic particles can emit green light under external ultraviolet light, making the display device green. When the upper electrode is positively charged, the negative white particles are driven to the upper electrode, making the display device white. Therefore, this embodiment can realize black, white and green three-state display of the longitudinally driven electrophoretic display device based on fluorescent electrophoretic particles by regulating positive and negative voltages and applying ultraviolet light. Fig. 9 shown.

[0101] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fluorescent electrophoretic ink, comprising an electrophoretic medium and first electrophoretic particles and second electrophoretic particles dispersed in the electrophoretic medium, wherein the first electrophoretic particles have a first charge polarity and present a first color under visible light irradiation, and the second electrophoretic particles have a second charge polarity and present a second color under visible light irradiation; It is characterized in that The fluorescent electrophoretic ink further includes third electrophoretic particles dispersed in the electrophoretic medium; The third electrophoretic particle has a first charge polarity or a second charge polarity; The third electrophoretic particles are in a colorless transparent state or a semi-transparent state under visible light, and emit fluorescence of a third color under non-visible light of a preset wavelength.

2. The fluorescent electrophoretic ink according to claim 1, characterized in that: The particle size of the third electrophoretic particle is smaller than the particle size of the first electrophoretic particle and the particle size of the second electrophoretic particle.

3. The fluorescent electrophoretic ink according to claim 2, characterized in that: The particle size of the third electrophoretic particles is 10-200 nm.

4. The fluorescent electrophoretic ink according to claim 1, characterized in that: The first color and the second color are different, and the first color and the second color are any two of white, black, red, orange, yellow, green, cyan, blue, purple or other colors.

5. The fluorescent electrophoretic ink according to claim 1, characterized in that: The third electrophoretic particle includes a fluorescent pigment, and the fluorescent pigment is at least one of an inorganic / organic up-conversion fluorescent pigment, an inorganic / organic ultraviolet down-conversion fluorescent pigment, and a composite fluorescent pigment.

6. The fluorescent electrophoretic ink according to claim 5, characterized in that: The third electrophoretic particle includes a fluorescent pigment layer and a polymer layer wrapped outside the fluorescent pigment layer.

7. The fluorescent electrophoretic ink according to claim 6, characterized in that: The fluorescent pigment is an up-conversion fluorescent pigment, and the third electrophoretic particle is prepared by the following steps: Step 1, ball-milling the up-conversion fluorescent pigment to a preset particle size; Step 2, adding the ball-milled fluorescent pigment, tetraethyl silicate and a silane coupling agent into a polar solvent and stirring to perform a coupling reaction to obtain coupled fluorescent pigment particles; Step 3, polymerizing the coupled fluorescent pigment particles with polymer monomers to obtain polymer-coated fluorescent electrophoretic particles.

8. The fluorescent electrophoretic ink according to claim 1, characterized in that: The third electrophoretic particle includes a nanoparticle containing a hydroxyl group on the surface, a quantum dot light-emitting layer disposed on the nanoparticle, and a polymer layer wrapped outside the quantum dot light-emitting layer.

9. The fluorescent electrophoretic ink according to claim 8, characterized in that: The third electrophoretic particle is prepared by the following steps: Step 1, mixing nanoparticles containing hydroxyl groups on the surface with a silane coupling agent, a non-polar solvent, and acetic acid according to a preset ratio, ball milling, and then dispersing the mixture in a non-polar solvent to obtain a nanoparticle solution; Step 2, dropping a perovskite quantum dot precursor solution into the nanoparticle solution, and stirring for a preset time to obtain nanoparticles loaded with perovskite quantum dots; Step 3: polymerizing the nanoparticles loaded with perovskite quantum dots with polymer monomers to obtain fluorescent electrophoretic particles coated with polymers.

10. A display device, characterized in that: It includes an upper electrode and a lower electrode, and the upper electrode and the lower electrode are used to connect the positive and negative electrodes of the power supply; A receiving cavity is formed between the upper electrode and the lower electrode, and the receiving cavity is filled with the fluorescent electrophoretic ink according to any one of claims 1 to 9.

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