Electrophoresis electronic paper display device
By filling microcapsules with phase change particles and utilizing the thermal management function of these particles, the problem of reduced response speed caused by increased viscosity of the electrophoretic dispersion medium at low temperatures was solved, enabling high-efficiency display and long-term cyclic use of electrophoretic electronic paper under low-temperature conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XINLI OPTICAL RENSHOU CO LTD
- Filing Date
- 2026-02-02
- Publication Date
- 2026-05-12
AI Technical Summary
In low-temperature environments, the viscosity of the electrophoretic dispersion medium in electrophoretic electronic paper increases, leading to a decrease in the response speed of both positively and negatively charged particles.
Microcapsules are filled with phase change particles. The phase change particles release heat when they change from a liquid phase to a solid phase at low temperatures to heat the electrophoretic dispersion medium, thereby increasing its temperature and reducing its viscosity. Under normal conditions, the phase change particles absorb heat when they change from a solid phase to a liquid phase, thus maintaining a stable temperature.
The response speed of the electrophoretic dispersion medium is improved in low-temperature environments, ensuring the normal display performance of electrophoretic electronic paper under low-temperature conditions and enabling long-term cyclic use under normal conditions.
Smart Images
Figure CN122018212A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to electronic paper display technology, and more particularly to an electrophoretic electronic paper display device. Background Technology
[0002] Electrophoretic electronic paper is a novel reflective "paper-like" display technology based on the electrophoretic phenomenon. It uses an electric field to control the floating of positively and negatively charged particles within microcapsules in an electrophoretic dispersion medium. When positively charged particles rise and negatively charged particles sink, the positively charged particles reflect or absorb ambient light; conversely, when negatively charged particles rise and positively charged particles sink, the negatively charged particles absorb or reflect ambient light, thus allowing the microcapsules to switch between reflective and absorbent states. Electrophoretic electronic paper exhibits bistable characteristics, meaning that once an image is formed, it can be maintained for a long time without continuous power supply, consuming power only when refreshing the screen; therefore, its power consumption is extremely low.
[0003] However, the electrophoretic dispersion medium inside the microcapsules is extremely sensitive to low temperatures. When the ambient temperature is low, the viscosity of the electrophoretic dispersion medium increases, which creates a large floating resistance for positively and negatively charged particles, thereby reducing the response speed of positively and negatively charged particles. Summary of the Invention
[0004] To address the shortcomings of the prior art, the present invention provides an electrophoretic electronic paper display device that can temporarily maintain the response speed of positively charged particles and negatively charged particles in a low-temperature environment.
[0005] The technical problem to be solved by the present invention is achieved through the following technical solution: An electrophoretic electronic paper display device includes a pixel layer comprising an array of multiple microcapsules, each microcapsule being filled with an electrophoretic dispersion medium, positively charged particles, and negatively charged particles; each microcapsule is also filled with phase change particles having a liquid phase and a solid phase; when the temperature of the electrophoretic dispersion medium is lower than the phase change temperature of the phase change particles, the phase change particles can transform from the liquid phase to the solid phase and release heat; when the temperature of the electrophoretic dispersion medium is higher than the phase change temperature of the phase change particles, the phase change particles can transform from the solid phase to the liquid phase and absorb heat.
[0006] Furthermore, the phase change particles are insoluble in the electrophoretic dispersion medium.
[0007] Furthermore, the phase transition temperature of the phase transition particles is between 0°C and 5°C.
[0008] Furthermore, the particle size of the phase transition particles is between 0.5 and 5 μm.
[0009] Furthermore, the mass ratio between the phase change particles and the electrophoretic system within the microcapsule is between 1:5 and 1:20.
[0010] Furthermore, the phase change particles are organic phase change particles or inorganic phase change particles modified with surface insulation coating.
[0011] Furthermore, of the positively charged particles and the negatively charged particles, one is a reflective particle and the other is a light-absorbing particle.
[0012] Furthermore, the electrophoretic electronic paper display device also includes an upper substrate, an upper electrode, a lower electrode, and a lower substrate. The upper electrode is disposed on the upper surface of the pixel layer, the upper substrate is disposed on the upper surface of the upper electrode, the lower electrode is disposed on the lower surface of the pixel layer, and the lower substrate is disposed on the lower surface of the lower electrode. The upper electrode and the lower electrode together form a driving electric field for driving the positively charged particles and negatively charged particles to float up and down in the electrophoretic dispersion medium.
[0013] Furthermore, the lower electrode is a TFT array electrode, and the upper electrode is a common electrode. The TFT array electrode, in conjunction with the common electrode, can apply a driving electric field to each microcapsule individually, thereby controlling each microcapsule to perform a display independently.
[0014] Furthermore, all microcapsules are divided into multiple pixel units, each containing multiple microcapsules; the lower electrode is a TFT array electrode, and the upper electrode is a common electrode. The TFT array electrode, in conjunction with the common electrode, can apply a driving electric field to each pixel unit individually, and simultaneously apply a driving electric field to all microcapsules within the same pixel unit, thereby individually controlling the display of each pixel unit, and simultaneously displaying all microcapsules within the same pixel unit.
[0015] The present invention has the following beneficial effects: The electrophoretic electronic paper display device of the present invention, by filling a certain amount of phase change particles into the microcapsules, releases heat by the phase change particles changing from a liquid phase to a solid phase in a low-temperature environment, thereby heating the electrophoretic dispersion medium to stabilize or increase the temperature of the electrophoretic dispersion medium, thereby reducing the viscosity of the electrophoretic dispersion medium in a low-temperature environment and increasing the response speed of the positively and negatively charged particles in a low-temperature environment; while in a normal environment, the phase change particles change from a solid phase to a liquid phase to absorb and store heat, thereby achieving the purpose of long-term cyclic use. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the stacked structure of the electrophoretic electronic paper display device provided by the present invention. Detailed Implementation
[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0018] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0019] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, "multiple" means two or more, unless otherwise explicitly specified.
[0020] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," and "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0021] Example 1 like Figure 1As shown, an electrophoretic electronic paper display device includes a pixel layer 3, which comprises a plurality of microcapsules 30 arranged in an array. Each microcapsule 30 is filled with an electrophoretic dispersion medium 31, positively charged particles 32, and negatively charged particles 33. Each microcapsule 30 is also filled with phase change particles 34, which have a liquid phase and a solid phase. When the temperature of the electrophoretic dispersion medium 31 is lower than the phase change temperature of the phase change particles 34, the phase change particles 34 can change from the liquid phase to the solid phase and release heat. When the temperature of the electrophoretic dispersion medium 31 is higher than the phase change temperature of the phase change particles 34, the phase change particles 34 can change from the solid phase to the liquid phase and absorb heat.
[0022] The electrophoretic electronic paper display device of the present invention fills a certain amount of phase change particles 34 into the microcapsules 30. In a low-temperature environment, the phase change particles 34 release heat by changing from a liquid phase to a solid phase, thereby heating the electrophoretic dispersion medium 31 to stabilize or increase the temperature of the electrophoretic dispersion medium 31, thereby reducing the viscosity of the electrophoretic dispersion medium 31 in a low-temperature environment and improving the response speed of the positively charged particles 32 and negatively charged particles 33 in a low-temperature environment. In a normal environment, the phase change particles 34 change from a solid phase to a liquid phase to absorb and store heat, thereby achieving the purpose of long-term cyclic use.
[0023] Although the phase transition heating time of the phase change particles 34 is limited, the electrophoretic electronic paper display device of the present invention still has significant application value in some short-term low-temperature application scenarios, such as inventory equipment for fresh products in cold storage (with short inventory times), or the short-term use of e-readers or electronic paper notebooks in low-temperature outdoor environments. Furthermore, the phase transition heating time of the phase change particles 34 can be further improved through material composition optimization or particle structure optimization.
[0024] The phase change particles 34 are insoluble in the electrophoretic dispersion medium 31. That is, when the electrophoretic dispersion medium 31 is an oily dispersion medium, the phase change particles 34 are water-based particles, and when the electrophoretic dispersion medium 31 is an aqueous dispersion medium, the phase change particles 34 are oil-based particles.
[0025] The phase transition temperature of the phase transition particle 34 should be close to the temperature at which the electrophoretic dispersion medium 31 experiences low-temperature failure, but slightly higher than that temperature. The low-temperature failure refers to the increased viscosity of the electrophoretic dispersion medium 31 due to low temperature, which affects the response speed of the positively charged particles 32 and the negatively charged particles 33, and this effect has caused significant problems with the screen refresh of the electrophoretic electronic paper display device.
[0026] The electrophoretic dispersion medium 31 typically experiences low-temperature failure at temperatures between 0°C and -10°C. Therefore, preferably, the phase transition temperature of the phase change particles 34 is between 0°C and 5°C, so that heat can be released through phase change before the electrophoretic dispersion medium 31 experiences low-temperature failure. This effectively avoids an increase in the viscosity of the electrophoretic dispersion medium 31 and also prevents premature phase change and ineffective heat release.
[0027] Preferably, the phase change particles 34 have a particle size between 0.5 and 5 μm (approximately the same as the particle size of the positively charged particles 32 and the negatively charged particles 33) to avoid the particle size being too large and hindering the up-and-down movement of the positively charged particles 32 and the negatively charged particles 33, and also to prevent the particle size being too small and causing adsorption of the positively charged particles 32 and the negatively charged particles 33.
[0028] Preferably, the mass ratio between the phase change particles 34 and the electrophoresis system within the microcapsule 30 (which contains only the electrophoretic dispersion medium 31, positively charged particles 32, and negatively charged particles 33, but not the phase change particles 34 or other functional particles) is between 1:5 and 1:20, so as to minimize interference with the electrophoresis effect while achieving the desired temperature control effect.
[0029] Meanwhile, the phase change particles 34 also need to be compatible with the electrophoretic system inside the microcapsule 30 to meet requirements such as high insulation, no chemical reaction with the microcapsule 30, positively charged particles 32 and negatively charged particles 33, and the ability to undergo multiple phase change cycles.
[0030] Therefore, preferably, the phase change particles 34 are organic phase change particles 34. The organic phase change particles 34 have advantages such as good insulation, uniform dispersion in the electrophoretic dispersion medium 31, easy control of phase change temperature, no water separation, and no corrosiveness.
[0031] The organic phase change particles 34 may be, but are not limited to, paraffin-based phase change particles 34, fatty acid-based phase change particles 34, fatty acid ester phase change particles 34, or fatty alcohol-based phase change particles 34, etc.
[0032] The paraffin-based phase change particles 34 use n-tetradecane as the base material and are compounded with one or more of n-dodecane, isododecane, n-pentadecanane, and n-hexadecane to adjust the phase change temperature to between 0°C and 5°C.
[0033] The fatty acid-based phase change particles 34 are made by combining stearic acid and palmitic acid, or by combining lauric acid, stearic acid and methyl palmitate, or by combining myristic acid, lauric acid and n-tetradecane, so as to adjust the phase change temperature to between 0°C and 5°C.
[0034] The fatty acid ester phase transition particles 34 are made by compounding ethyl laurate with n-tetradecane, or butyl palmitate with n-dodecane, or methyl stearate with ethyl laurate, to adjust the phase transition temperature to between 0°C and 5°C.
[0035] The fatty alcohol-based phase change particles 34 are based on dodecyl alcohol as the core material and are compounded with one or more of n-dodecane, n-tetradecane or ethyl laurate to adjust the phase change temperature to between 0°C and 5°C.
[0036] Of course, the phase change particles 34 can also be inorganic phase change particles 34 that have been modified by surface insulation coating.
[0037] The inorganic phase change particles 34 may be, but are not limited to, sodium acetate trihydrate or anhydrous molten salts, and their surface insulating coating material may be, but is not limited to, silane coupling agents or polymer resins; the silane coupling agent is preferably a hydrophobic alkyl / alkoxy type, and may be, but is not limited to, methyltrimethoxysilane, methyltriethoxysilane, octyltrimethoxysilane, dodecyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane; the polymer resin is preferably a non-aqueous / hydrophobic resin, and may be, but is not limited to, polymethyl methacrylate, methyl acrylate-methyl methacrylate copolymer, polyethylene, polystyrene, polypropylene, polyolefin wax, styrene-butadiene copolymer, non-aqueous polyurethane, polydimethylsiloxane, silicone resin, polylactic acid, polycaprolactone, or epoxy resin.
[0038] Of the positively charged particles 32 and negatively charged particles 33, one is a reflective particle and the other is a light-absorbing particle. That is, if the positively charged particle 32 is a reflective particle, then the negatively charged particle 33 is a light-absorbing particle, and vice versa.
[0039] When the reflective particles float in the electrophoretic dispersion medium 31 and the light-absorbing particles sink in the electrophoretic dispersion medium 31, the reflective particles gather on the upper surface of the microcapsule 30 to reflect ambient light, thereby making the microcapsule 30 appear in a color corresponding to the reflective particles; when the reflective particles sink in the electrophoretic dispersion medium 31 and the light-absorbing particles float in the electrophoretic dispersion medium 31, the light-absorbing particles gather on the upper surface of the microcapsule 30 to absorb ambient light, thereby making the microcapsule 30 appear black.
[0040] The reflective particles can be, but are not limited to, titanium dioxide particles, zinc oxide particles, zirconium dioxide particles, and titanium dioxide-barium sulfate composite particles. All of the aforementioned particles can reflect ambient light, making the microcapsule 30 appear white. If color display is required, the aforementioned particles can be used as the core, and organic pigments of different colors can be used as the coating layer of the core, so that the reflective particles can reflect a portion of the ambient light that corresponds to the color of the coating layer, thereby making the microcapsule 30 appear the color corresponding to the coating layer.
[0041] The organic pigment may be, but is not limited to, azo red pigment, phthalocyanine green pigment, phthalocyanine blue pigment, or azo yellow pigment; the light-absorbing particles may be, but are not limited to, carbon black particles, aniline black particles, chrome black particles, or iron black particles.
[0042] The electrophoretic electronic paper display device further includes an upper substrate 1, an upper electrode 2, a lower electrode 4, and a lower substrate 5. The upper electrode 2 is disposed on the upper surface of the pixel layer 3, the upper substrate 1 is disposed on the upper surface of the upper electrode 2, the lower electrode 4 is disposed on the lower surface of the pixel layer 3, and the lower substrate 5 is disposed on the lower surface of the lower electrode 4. The upper electrode 2 and the lower electrode 4 together form a driving electric field for driving the positively charged particles 32 and the negatively charged particles 33 to float up and down in the electrophoretic dispersion medium 31.
[0043] When the upper electrode 2 is positively charged and the lower electrode 4 is negatively charged, the positively charged particles 32 are repelled by the upper electrode 2 and attracted by the lower electrode 4, while the negatively charged particles 33 are attracted by the upper electrode 2 and repelled by the lower electrode 4. The positively charged particles 32 sink in the electrophoretic dispersion medium 31, and the negatively charged particles 33 float in the electrophoretic dispersion medium 31. When the upper electrode 2 is negatively charged and the lower electrode 4 is positively charged, the positively charged particles 32 are attracted by the upper electrode 2 and repelled by the lower electrode 4, while the negatively charged particles 33 are repelled by the upper electrode 2 and attracted by the lower electrode 4. The positively charged particles 32 float in the electrophoretic dispersion medium 31, and the negatively charged particles 33 sink in the electrophoretic dispersion medium 31.
[0044] The upper substrate 1 and the lower substrate 5 can be rigid substrates such as glass substrates, ceramic substrates or sapphire substrates, or flexible films such as polyimide films, polyester films, cyclic olefin polymer films or polycarbonate films.
[0045] Preferably, the lower electrode 4 is a TFT array electrode, and the upper electrode 2 is a common electrode. The TFT array electrode, in conjunction with the common electrode, can apply a driving electric field to each microcapsule 30 individually, thereby controlling each microcapsule 30 to perform display independently.
[0046] Alternatively, based on the required resolution and power consumption requirements, all microcapsules 30 can be divided into multiple pixel units, each containing multiple microcapsules 30. The TFT array electrode, in conjunction with the common electrode, can apply a driving electric field to each pixel unit individually, and simultaneously apply a driving electric field to all microcapsules 30 within the same pixel unit, thereby individually controlling the display of each pixel unit, and simultaneously displaying all microcapsules 30 within the same pixel unit.
[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and not to limit them. Although the embodiments of the present invention have been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the embodiments of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. An electrophoretic electronic paper display device, comprising a pixel layer, the pixel layer comprising a plurality of microcapsules arranged in an array, each microcapsule being filled with an electrophoretic dispersion medium, positively charged particles, and negatively charged particles; characterized in that, Each microcapsule is also filled with phase change particles, which have a liquid phase and a solid phase. When the temperature of the electrophoretic dispersion medium is lower than the phase change temperature of the phase change particles, the phase change particles can transform from the liquid phase to the solid phase and release heat. When the temperature of the electrophoretic dispersion medium is higher than the phase change temperature of the phase change particles, the phase change particles can transform from the solid phase to the liquid phase and absorb heat.
2. The electrophoretic electronic paper display device according to claim 1, characterized in that, The phase change particles are insoluble in the electrophoretic dispersion medium.
3. The electrophoretic electronic paper display device according to claim 1, characterized in that, The phase transition temperature of the phase transition particles is between 0℃ and 5℃.
4. The electrophoretic electronic paper display device according to claim 1, characterized in that, The particle size of the phase change particles is between 0.5 and 5 μm.
5. The electrophoretic electronic paper display device according to claim 1, characterized in that, The mass ratio between the phase transition particles and the electrophoretic system within the microcapsule is between 1:5 and 1:
20.
6. The electrophoretic electronic paper display device according to claim 1, characterized in that, The phase change particles are organic phase change particles or inorganic phase change particles modified with surface insulation coating.
7. The electrophoretic electronic paper display device according to claim 1, characterized in that, Of the positively charged particles and the negatively charged particles, one is a reflective particle and the other is a light-absorbing particle.
8. The electrophoretic electronic paper display device according to claim 1, characterized in that, The electrophoretic electronic paper display device further includes an upper substrate, an upper electrode, a lower electrode, and a lower substrate. The upper electrode is disposed on the upper surface of the pixel layer, the upper substrate is disposed on the upper surface of the upper electrode, the lower electrode is disposed on the lower surface of the pixel layer, and the lower substrate is disposed on the lower surface of the lower electrode. The upper electrode and the lower electrode together form a driving electric field for driving the positively charged particles and negatively charged particles to float up and down in the electrophoretic dispersion medium.
9. The electrophoretic electronic paper display device according to claim 1, characterized in that, The lower electrode is a TFT array electrode, and the upper electrode is a common electrode. The TFT array electrode, together with the common electrode, can apply a driving electric field to each microcapsule individually, thereby controlling each microcapsule to display independently.
10. The electrophoretic electronic paper display device according to claim 1, characterized in that, All microcapsules are divided into multiple pixel units, and each pixel unit contains multiple microcapsules. The lower electrode is a TFT array electrode, and the upper electrode is a common electrode. The TFT array electrode, together with the common electrode, can apply a driving electric field to each pixel unit individually, and apply a driving electric field to all microcapsules in the same pixel unit simultaneously, thereby controlling each pixel unit to display individually, and displaying all microcapsules in the same pixel unit simultaneously.