Electronic paper structure and manufacturing method thereof, electronic paper

Abstract

An electronic paper structure, a manufacturing method thereof and an electronic paper, the electronic paper structure comprising a first substrate, a first electrode layer, a second electrode layer and an insulation layer stacked in sequence, wherein an ink and a conductive liquid are arranged on one side of the insulation layer away from the second electrode layer; the second electrode layer has a thermal expansion coefficient greater than that of the first electrode layer; and the first electrode layer and the second electrode layer are used to protrude in a direction away from the first substrate after the electronic paper structure is powered on. The electronic paper structure can solve the aggregation phenomenon of the ink during the shrinkage process.

Description

Technical Field

[0001] This application relates to the field of display device technology, specifically to an electronic paper structure and its manufacturing method, and electronic paper. Background Technology

[0002] Electro-wetting electronic paper is a novel type of display device. It utilizes the effect of interfacial charge on interfacial tension to alter the contact angle between charged ink droplets and the contact surface, causing the droplets to contract and expand, thus achieving the function of an optical switch. When no driving voltage is applied to the pixel electrode, black ink spreads uniformly on the insulating hydrophobic layer, and the pixel unit appears completely dark. When a driving voltage is applied to the pixel electrode, the ink contracts and shrinks to one side into a droplet shape, at which point the pixel unit appears white, resembling a reflective substrate.

[0003] However, ink inevitably aggregates during the shrinkage process, eventually causing the aggregated ink to form dark spots within pixels, affecting display quality. Furthermore, the location of ink aggregation is random, not fixed. Therefore, resolving this ink aggregation issue during shrinkage becomes crucial. Summary of the Invention

[0004] The purpose of this application is to provide an electronic paper structure and its manufacturing method, and to solve the problem of ink aggregation during the shrinkage process.

[0005] To achieve the objectives of this application, the following technical solution is provided:

[0006] In a first aspect, the present invention provides an electronic paper structure, comprising a first substrate, a first electrode layer, a second electrode layer and an insulating layer stacked together, wherein ink and a conductive liquid are disposed on the side of the insulating layer facing away from the second electrode layer; the coefficient of thermal expansion of the second electrode layer is greater than the coefficient of thermal expansion of the first electrode layer; when the electronic paper structure is powered on, the first electrode layer and the second electrode layer are configured to protrude in a direction away from the first substrate.

[0007] In some embodiments, the coefficient of thermal expansion of the first electrode layer is 5*10. -6 / ℃~10*10 -6 / ℃.

[0008] In some embodiments, the coefficient of thermal expansion of the second electrode layer is 25*10. -6 / ℃~45*10 -6 / ℃.

[0009] In some embodiments, the material of the first electrode layer includes one or more of iron, nickel, steel, and germanium.

[0010] In some embodiments, the material of the second electrode layer includes one or more of aluminum, zinc, tin, and lead.

[0011] In some embodiments, along the first direction, the first electrode layer has a structure that is thin in the middle and thick at both ends; the second electrode layer has a structure that is thick in the middle and thin at both ends, and the first direction intersects with the thickness direction of the electronic paper structure.

[0012] In some embodiments, the sum of the thicknesses of the first electrode layer and the second electrode layer is H0. Along the first direction, the first electrode layer includes a first thickness region, a second thickness region, and a third thickness region connected in sequence. The first thickness region is located in the middle of the first electrode layer. The thickness of the first thickness region is 0.1H0 to 0.5H0, the thickness of the second thickness region is 0.25H0 to 0.75H0, and the thickness of the third thickness region is 0.5H0 to 0.9H0.

[0013] In some embodiments, the thickness of the first thickness region is 0.3H0, the thickness of the second thickness region is 0.5H0, and the thickness of the third thickness region is 0.75H0.

[0014] In some embodiments, the thickness and H0 of the first electrode layer and the second electrode layer are 80 nm to 200 nm; along the first direction, the length L of the first electrode layer and / or the second electrode layer is 200 μm to 1200 μm.

[0015] In some embodiments, the insulating layer includes a hydrophobic substrate and a hydrophilic portion, the hydrophobic substrate being connected to the second electrode layer, the hydrophobic substrate being deformable, and the hydrophilic portion being located on the side of the hydrophobic substrate facing away from the second electrode layer; the insulating layer includes a hydrophobic state and a hydrophilic state, in which the hydrophilic portion is embedded inside the hydrophobic substrate in the hydrophobic state; in the hydrophilic state, the hydrophobic substrate is deformed, and the hydrophilic portion is exposed to the conductive liquid.

[0016] In some embodiments, there are multiple hydrophilic portions, which are arranged sequentially at intervals along a first direction, the first direction intersecting the thickness direction of the electronic paper structure.

[0017] In some embodiments, the hydrophobic substrate includes one or more of polydimethylsiloxane, fluorinated ethylene propylene copolymer, polychlorotrifluoroethylene, and fluororubber.

[0018] In some embodiments, the hydrophilic portion includes one or more of silica, titanium dioxide, polyacrylic acid, and polyvinylpyrrolidone.

[0019] In some embodiments, the thickness H1 of the hydrophobic substrate is 500 nm to 1000 nm.

[0020] In some embodiments, the thickness H2 of the hydrophilic portion is 20 nm to 50 nm.

[0021] In a second aspect, the present invention provides a method for manufacturing an electronic paper structure, the method being used to manufacture an electronic paper structure as described in any one of the embodiments of the first aspect, the method comprising: sequentially disposing a first electrode layer, a second electrode layer and an insulating layer on a first substrate.

[0022] In some embodiments, the method for fabricating the insulating layer includes: providing a hydrophobic substrate; pre-stretching the hydrophobic substrate to elongate it; providing a hydrophilic portion on the surface of the pre-stretched hydrophobic substrate; and stress-relieving the pre-stretched hydrophobic substrate with the hydrophilic portion to shrink it, thereby obtaining the insulating layer; wherein the insulating layer includes a hydrophobic state and a hydrophilic state, wherein in the hydrophobic state, the hydrophilic portion is embedded inside the hydrophobic substrate; and in the hydrophilic state, the hydrophobic substrate deforms, and the hydrophilic portion is exposed to the conductive liquid.

[0023] In some embodiments, the hydrophobic substrate is pre-stretched, and the elongation of the pre-stretched hydrophobic substrate is 150% to 300%.

[0024] In some embodiments, the hydrophobic substrate is pre-stretched at a rate of 2 μm / s to 5 μm / s.

[0025] In some embodiments, a hydrophilic portion is provided on the surface of the pre-stretched hydrophobic substrate, including: performing a local hardening treatment on the surface of the pre-stretched hydrophobic substrate to give the surface of the pre-stretched hydrophobic substrate a hardened portion; and providing the hydrophilic portion on the hardened portion.

[0026] In some embodiments, the thickness of the hardened portion is 20 nm to 50 nm.

[0027] Thirdly, the present invention provides an electronic paper comprising an electronic paper structure as described in any one of the embodiments of the first aspect; or, the electronic paper comprising an electronic paper structure manufactured by a method for manufacturing an electronic paper structure as described in any one of the embodiments of the second aspect.

[0028] This invention provides an electronic paper structure with a double electrode layer. Compared with existing electronic paper structures, this structure has a first electrode layer and a second electrode layer with different coefficients of thermal expansion, and the coefficient of thermal expansion of the upper second electrode layer is greater than that of the lower first electrode layer. When the electronic paper structure is powered on, the first and second electrode layers bend due to the electrothermal effect and their different coefficients of thermal expansion, forming an arched structure. During the formation of the arch, a downward thrust is exerted on the ink, thereby improving the problem of ink aggregation. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram illustrating the display effects of an electronic paper structure in one embodiment when it is not powered on and when it is powered on.

[0031] Figure 2 This is a cross-sectional schematic diagram of an electronic paper structure according to one implementation method;

[0032] Figure 3 This is a cross-sectional schematic diagram of an electronic paper structure in an unpowered state according to one embodiment;

[0033] Figure 4 This is a cross-sectional schematic diagram of an electronic paper structure in an electrically powered state, according to one embodiment.

[0034] Figure 5 This is a schematic cross-sectional view of the first electrode layer and the second electrode layer in one embodiment;

[0035] Figure 6 This is a cross-sectional schematic diagram of the hydrophilic state of the insulating layer in one embodiment;

[0036] Figure 7 This is a cross-sectional schematic diagram of the hydrophobic state of the insulating layer in one embodiment;

[0037] Figure 8 This is a schematic diagram illustrating a method for fabricating an electronic paper structure according to one implementation.

[0038] Figure 9 This is a flowchart illustrating a method for fabricating an electronic paper structure in one implementation.

[0039] Figure 10This is a flowchart of step S20 in one embodiment of the method for manufacturing an electronic paper structure.

[0040] Explanation of reference numerals in the attached figures:

[0041] 100 - Electronic paper structure, 10 - First substrate, 20 - First electrode layer, 21 - First thickness region, 22 - Second thickness region, 23 - Third thickness region, 30 - Second electrode layer, 31 - Fourth thickness region, 32 - Fifth thickness region, 33 - Sixth thickness region, 40 - Insulating layer, 41 - Hydrophobic substrate, 42 - Hydrophilic part, 43 - Slit, 44 - Hardened part, 50 - Ink, 60 - Conductive liquid, 70 - Pixel wall, 80 - Third electrode layer, 90 - Second substrate, Z - Thickness direction, X - First direction. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0044] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0045] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0046] Electrowetting electronic paper structures refer to the phenomenon where applying a voltage between upper and lower substrates alters the surface tension between a liquid and a solid, thereby changing the contact angle and causing the droplet to deform and shift. Electrowetting electronic paper structures can be specifically used in the fabrication of electronic paper.

[0047] In some embodiments, in the prior art, a conventional electrowetting electronic paper structure, from bottom to top along the thickness direction, includes: a lower substrate, a lower working electrode, a hydrophobic insulating layer, ink, pixel walls, a conductive liquid, an upper working electrode, and an upper protective substrate. The lower substrate, lower working electrode, and hydrophobic insulating layer are connected sequentially; the hydrophobic insulating layer and the upper working electrode are spaced apart; the ink, pixel walls, and conductive liquid are disposed between the hydrophobic insulating layer and the upper working electrode; ink is present between the pixel walls, and the space between the pixel walls constitutes a pixel unit. Please refer to [reference needed]. Figure 1 (1) of.

[0048] However, please refer to Figure 1 (2) When a driving voltage is applied to the pixel electrodes (lower working electrode and upper working electrode) of the conventional electrowetting electronic paper structure, ink inevitably aggregates during the shrinkage process, eventually causing the aggregated ink to form dark spots in the pixel. Figure 1 As shown in (2)A), the ink aggregation affects the display effect, and the location of ink aggregation is also random, not fixed. Therefore, how to solve the ink aggregation phenomenon during the shrinkage process has become the key. Based on this technical problem, the present invention provides an electronic paper structure that can solve the ink aggregation phenomenon during the shrinkage process.

[0049] [Electronic Paper Structure]

[0050] For some implementation methods, please refer to Figure 2 The electronic paper structure 100 includes a first substrate 10, a first electrode layer 20, a second electrode layer 30, and an insulating layer 40 stacked together. Ink 50 and conductive liquid 60 are disposed on the side of the insulating layer 40 facing away from the second electrode layer 30. The coefficient of thermal expansion of the second electrode layer 30 is greater than that of the first electrode layer 20. When the electronic paper structure 100 is powered on, the first electrode layer 20 and the second electrode layer 30 are used to protrude in a direction away from the first substrate 10.

[0051] In a specific embodiment, please refer to Figure 2 The electronic paper structure 100, from bottom to top along the thickness direction Z, includes: a first substrate 10, a first electrode layer 20, a second electrode layer 30, an insulating layer 40, a pixel wall 70, a third electrode layer 80, and a second substrate 90. The first substrate 10, the first electrode layer 20, the second electrode layer 30, and the insulating layer 40 are connected sequentially. The insulating layer 40 and the third electrode layer 80 are spaced apart. Ink 50, the pixel wall 70, and the conductive liquid 60 are disposed between the insulating layer 40 and the third electrode layer 80.

[0052] In a specific embodiment, both the first electrode layer 20 and the second electrode layer 30 are made of metal, and they are made of different metals with different coefficients of thermal expansion. It should be noted that objects expand and contract due to temperature changes, and their ability to change is expressed as the change in length caused by a unit temperature change under isobaric conditions, i.e., using the coefficient of thermal expansion (unit: 1 / ℃ or ppm / ℃).

[0053] In a specific embodiment, the coefficient of thermal expansion is a physical quantity that characterizes the change in length or volume of an object due to temperature changes. A large coefficient of thermal expansion indicates that the material is more sensitive to temperature changes, and significant volume or size changes will occur when the temperature fluctuates. The different coefficients of thermal expansion of the first electrode layer 20 and the second electrode layer 30 indicate that their sensitivity at the same temperature is different, and the volume or size changes of the first electrode layer 20 and the second electrode layer 30 will be different when the temperature fluctuates.

[0054] In a specific embodiment, the coefficient of thermal expansion of the second electrode layer 30 is greater than that of the first electrode layer 20. Therefore, the second electrode layer 30, located on the upper layer, has a greater deformation capacity. After the electronic paper structure 100 is powered on, both the first electrode layer 20 and the second electrode layer 30 will bulge upwards due to the electrothermal effect, forming an arched structure. Because the second electrode layer 30 has a greater deformation capacity, it can form a larger arched structure.

[0055] In a specific embodiment, please refer to Figure 3 and Figure 4 The electronic paper structure 100 includes an unpowered state ( Figure 3 ) and power-on state ( Figure 4 The unpowered state refers to the electronic paper structure 100 being without power, so the first electrode layer 20 and the second electrode layer 30 will not deform due to the electrothermal effect, and the first electrode layer 20 and the second electrode layer 30 can be approximated as planar. The powered state refers to the electronic paper structure 100 being powered, where the first electrode layer 20 and the second electrode layer 30 deform due to the electrothermal effect, and both bulge upwards (towards the direction closer to the third electrode layer 80), together forming an arched structure. Figure 4 ).

[0056] In a specific embodiment, the top view of the first electrode layer 20 and the second electrode layer 30 is convex-hull shaped, meaning that the first electrode layer 20 and the second electrode layer 30 protrude at the middle position of the pixel unit, forming a structure that is high in the middle and low around the edges. In this way, the ink 50 will flow downwards along the inclined surface formed by the second electrode layer 30 under the action of gravity. Of course, the cross-sectional side view of the first electrode layer 20 and the second electrode layer 30 is an arched structure, forming a structure that is high in the middle and low on both sides.

[0057] This invention provides an electronic paper structure 100 with a double electrode layer. Compared with the electronic paper structure 100 in the prior art, the electronic paper structure 100 has a first electrode layer 20 and a second electrode layer 30 with different coefficients of thermal expansion, and the coefficient of thermal expansion of the upper second electrode layer 30 is greater than that of the lower first electrode layer 20. When the electronic paper structure 100 is powered on, the first electrode layer 20 and the second electrode layer 30 bend due to the electrothermal effect and their different coefficients of thermal expansion, forming an arched structure. During the formation of the arch, a downward thrust is exerted on the ink 50, thereby improving the problem of ink 50 aggregation.

[0058] In some embodiments, the material of the first electrode layer 20 includes one or more of iron, nickel, steel, and germanium. The coefficient of thermal expansion of the first electrode layer 20 is 5*10⁻⁶. -6 / ℃~10*10 -6 / ℃.

[0059] In a specific embodiment, the coefficient of thermal expansion of the first electrode layer 20 can be 5*10. -6 / ℃, 5.5*10 -6 / ℃、6*10 -6 / ℃, 6.5*10 -6 / ℃、7*10 -6 / ℃, 7.5*10 -6 / ℃、8*10 -6 / ℃, 8.5*10 -6 / ℃、9*10 -6 / ℃, 9.5*10 -6 / ℃, 10*10 -6 / ℃.

[0060] In some embodiments, the material of the second electrode layer 30 includes one or more of aluminum, zinc, tin, and lead. The coefficient of thermal expansion of the second electrode layer 30 is 25 × 10⁻⁶. -6 / ℃~45*10 -6 / ℃.

[0061] In a specific embodiment, the coefficient of thermal expansion of the second electrode layer 30 can be 25*10. -6 / ℃, 27*10 -6 / ℃, 29*10 -6 / ℃、31*10 -6 / ℃、33*10 -6 / ℃, 35*10 -6 / ℃, 37*10 -6 / ℃, 39*10 -6 / ℃、41*10 -6 / ℃、43*10 -6 / ℃, 45*10 -6 / ℃.

[0062] For some implementation methods, please refer to Figure 5 Along the first direction X, the first electrode layer 20 has a structure that is thin in the middle and thick at both ends; the second electrode layer 30 has a structure that is thick in the middle and thin at both ends. The first direction X intersects with the thickness direction Z of the electronic paper structure 100. Specifically, the first direction X is perpendicular to the thickness direction Z of the electronic paper structure 100 and is parallel to the surface of the first substrate 10.

[0063] In a specific embodiment, in the unpowered state, the sum of the thicknesses of the first electrode layer 20 and the second electrode layer 30 is a fixed value, and the side of the second electrode layer 30 facing away from the first substrate 10 is parallel to the surface of the first substrate 10. In the unpowered state, the first electrode layer 20 has a structure that is thin in the middle and thick at both ends, that is, along the first direction X, the thickness at both ends of the first electrode layer 20 is larger, and the thickness in the middle is smaller; conversely, the thickness at both ends of the second electrode layer 30 is smaller, and the thickness in the middle is larger.

[0064] In a specific embodiment, to achieve the effect of the first electrode layer 20 and the second electrode layer 30 being curved in the middle (protruding in the middle) and not curved at both ends, the middle thickness of the second electrode layer 30 can be increased. Because the second electrode layer 30 is the main deformation layer, increasing its middle thickness allows it to have a greater thickness after convexity, which can address stress concentration issues. Simultaneously, combined with the relatively thin middle thickness of the first electrode layer 20, the total thickness of the two electrode layers becomes uniform.

[0065] The present invention sets the first electrode layer 20 to be thin in the middle and thick at both ends, and the second electrode layer 30 to be thick in the middle and thin at both ends, so that the dual electrode layers can be fixed in the cavity of the pixel unit formed by the pixel wall 70, and the dual electrode layers are bent only in the middle and not on the sides, so that the ink 50 can slide down along the unbent part after the dual electrode layers are bent.

[0066] For some implementation methods, please refer to Figure 5 The sum of the thicknesses of the first electrode layer 20 and the second electrode layer 30 is H0. Along the first direction X, the first electrode layer 20 includes a first thickness region 21, a second thickness region 22 and a third thickness region 23 connected in sequence. The first thickness region 21 is located in the middle of the first electrode layer 20, and the thickness of the first thickness region 21 is 0.1H0 to 0.5H0. The thickness of the second thickness region 22 is 0.25H0 to 0.75H0, and the thickness of the third thickness region 23 is 0.5H0 to 0.9H0.

[0067] In a specific embodiment, the cross-section of the first electrode layer 20 is axisymmetric along the thickness direction Z. The first thickness region 21 is located in the middle of the first electrode layer 20, there are two second thickness regions 22, located at both ends of the first thickness region 21 along the first direction X, and there are two third thickness regions 23, located at both ends of the first thickness region 21 along the first direction X. The two third thickness regions 23 are located on the outermost side.

[0068] In a specific embodiment, since the cross-section of the first electrode layer 20 is axially symmetric, only the first thickness region 21, the second thickness region 22, and the third thickness region 23 on one side are used as examples for explanation. The first thickness region 21 is the thinnest, that is, the middle of the first electrode layer 20 is thin; the thickness of the second thickness region 22 is greater than the thickness of the first thickness region 21, and the thickness of the third thickness region 23 is greater than the thickness of the second thickness region 22, that is, the two ends of the first electrode layer 20 are thick, so that the first electrode layer 20 exhibits a gradient thickness variation along the first direction X towards both ends.

[0069] For some implementation methods, please refer to Figure 5 Along the first direction X, the second electrode layer 30 includes a fourth thickness region 31, a fifth thickness region 32 and a sixth thickness region 33 connected in sequence. The fourth thickness region 31 is located in the middle of the second electrode layer 30, and the thickness of the fourth thickness region 31 is 0.5H0 to 0.9H0. The thickness of the fifth thickness region 32 is 0.25H0 to 0.75H0, and the thickness of the sixth thickness region 33 is 0.1H0 to 0.5H0.

[0070] In a specific embodiment, along the thickness direction Z, the fourth thickness region 31 and the first thickness region 21 are directly opposite each other, the fifth thickness region 32 and the second thickness region 22 are directly opposite each other, and the sixth thickness region 33 and the third thickness region 23 are directly opposite each other. The sum of the thicknesses of the first electrode layer 20 and the second electrode layer 30 is H0; therefore, the thickness of the first thickness region 21 plus the thickness of the fourth thickness region 31 is H0, the thickness of the second thickness region 22 plus the thickness of the fifth thickness region 32 is H0, and the thickness of the third thickness region 23 plus the thickness of the sixth thickness region 33 is H0.

[0071] In a specific embodiment, since the cross-section of the second electrode layer 30 is also axially symmetric, only the fourth thickness region 31, the fifth thickness region 32, and the sixth thickness region 33 on one side are used as examples for explanation. The fourth thickness region 31 is the thickest, that is, the middle of the second electrode layer 30 is thick; the thickness of the fifth thickness region 32 is less than the thickness of the fourth thickness region 31, and the thickness of the sixth thickness region 33 is less than the thickness of the fifth thickness region 32, that is, the two ends of the second electrode layer 30 are thin, so that the second electrode layer 30 also exhibits a gradient thickness variation along the first direction X towards both ends.

[0072] In some embodiments, the thickness of the first thickness region 21 is 0.3H0, the thickness of the second thickness region 22 is 0.5H0, and the thickness of the third thickness region 23 is 0.75H0. The thickness of the fourth thickness region 31 is 0.7H0, the thickness of the fifth thickness region 32 is 0.5H0, and the thickness of the sixth thickness region 33 is 0.25H0. ​​The thickness ratio of the fourth thickness region 31 to the first thickness region 21 is 2.33, the thickness ratio of the fifth thickness region 32 to the second thickness region 22 is 1, and the thickness ratio of the sixth thickness region 33 to the third thickness region 23 is 0.33.

[0073] In some embodiments, the thickness and H0 of the first electrode layer 20 and the second electrode layer 30 are 80 nm to 200 nm, whether in the unpowered state or the powered state. Optionally, the thickness and H0 of the first electrode layer 20 and the second electrode layer 30 can be 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, or 200 nm.

[0074] In some embodiments, in the unpowered or powered state, the length L of the first electrode layer 20 and / or the second electrode layer 30 along the first direction X is 200 μm to 1200 μm. Optionally, the length L of the first electrode layer 20 and / or the second electrode layer 30 can be 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, or 1200 μm.

[0075] To ensure that the ink 50 can slide down along the formed arched structure after the first electrode layer 20 and the second electrode layer 30 are arched, the present invention also provides an insulating layer 40 with a special structure. The insulating layer 40 deforms along with the arched double electrode layers, and after deformation, the insulating layer 40 changes from hydrophobic to oleophilic to hydrophilic to oleophobic, further increasing the contact angle between the ink 50 and the special insulating layer 40, thereby improving the problem of ink 50 aggregation.

[0076] For some implementation methods, please refer to Figure 6 and Figure 7 The insulating layer 40 includes a hydrophobic substrate 41 and a hydrophilic portion 42. The hydrophobic substrate 41 is connected to the second electrode layer 30 and is deformable. The hydrophilic portion 42 is located on the side of the hydrophobic substrate 41 facing away from the second electrode layer 30. The insulating layer 40 includes a hydrophobic state and a hydrophilic state. In the hydrophobic state, the hydrophilic portion 42 is embedded inside the hydrophobic substrate 41. In the hydrophilic state, the hydrophobic substrate 41 is deformed and the hydrophilic portion 42 is exposed to the conductive liquid 60.

[0077] In a specific embodiment, the insulating layer 40 is disposed on the side of the second electrode layer 30 facing away from the first substrate 10. The insulating layer 40 is also the layer that is in direct contact with the ink 50. Therefore, when the dual electrode layers (first electrode layer 20 and second electrode layer 30) bulge upward and deform, the insulating layer 40 will also deform accordingly, that is, the insulating layer 40 bulges upward to form an arched structure.

[0078] In a specific embodiment, the hydrophobic substrate 41 is the main supporting structure of the insulating layer 40. The hydrophobic substrate 41 is hydrophobic and elastic. When energized, the dual electrode layer protrudes upward and compresses the insulating layer 40 to form an arched structure. The side of the insulating layer 40 facing away from the first substrate 10 expands, increasing the surface area of ​​the insulating layer 40 facing away from the first substrate 10, thus exposing the hydrophilic portion 42 embedded inside the hydrophobic substrate 41.

[0079] In a specific embodiment, the hydrophobic state of the insulating layer 40 is the state of the insulating layer 40 in the unpowered state of the electronic paper structure 100. The hydrophilic portion 42 is embedded inside the hydrophobic substrate 41, and the hydrophilic portion 42 is located on the side of the hydrophobic substrate 41 closest to the ink 50. The hydrophilic state of the insulating layer 40 is the state of the insulating layer 40 in the powered state of the electronic paper structure 100. The hydrophobic substrate 41 protrudes upward and extends towards the ink 50, while the hydrophilic portion 42 is exposed to the conductive liquid 60.

[0080] In a specific embodiment, the hydrophobic substrate 41 is made of a polymer material. In the unenergized state, the side of the hydrophobic substrate 41 facing the ink 50 has slits 43, and the hydrophilic portion 42 is housed in the slits 43, thus embedding itself inside the hydrophobic substrate 41. Simultaneously, under the pressure of the inner wall of the slits 43, the hydrophilic portion 42 is hidden inside the insulating layer 40 and does not come into contact with the outside (ink 50). The large surface of the hydrophobic substrate 41 is in direct contact with the ink, so the insulating layer 40 exhibits a hydrophobic state. In the energized state, the insulating layer 40 is compressed and deformed, the slits 43 unfold, and the hydrophilic portion 42 is exposed and comes into contact with the outside, so the insulating layer 40 exhibits a hydrophilic state.

[0081] In a specific embodiment, in the unpowered state, the area occupied by the hydrophilic portion 42 in the orthogonal projection of the insulating material along the thickness direction Z onto the first substrate 10 can be A; in the powered state, the area occupied by the hydrophilic portion 42 in the orthogonal projection of the insulating material along the thickness direction Z onto the first substrate 10 can be B, where A < B. It is understood that in the unpowered state, since the hydrophilic portion 42 is hidden through the slit 43, the area occupied by the hydrophilic portion 42 is relatively small, even approaching 0; in the powered state, since the hydrophilic portion 42 is exposed through the upward convexity, the area occupied by the hydrophilic portion 42 is relatively large.

[0082] This invention provides a stable display effect by providing a hydrophilic portion 42 on a hydrophobic substrate 41. In the unpowered state, the hydrophilic portion 42 is embedded and hidden inside the hydrophobic substrate 41 and does not come into contact with the outside. The insulating layer 40 is in a hydrophobic and oleophilic state, and the ink 50 adheres to the surface of the hydrophobic substrate 41. In the powered state, the insulating layer 40 is arched and deformed, the hydrophilic portion 42 is exposed to the conductive liquid 60, the insulating layer 40 is in a hydrophilic and oleophobic state, and the ink 50 slides down the arched insulating layer 40 without accumulating.

[0083] For some implementation methods, please refer to Figure 6 and Figure 7 The number of hydrophilic portions 42 is multiple, and the multiple hydrophilic portions 42 are arranged sequentially and spaced apart along the first direction X, which intersects with the thickness direction Z of the electronic paper structure 100. Specifically, the multiple hydrophilic portions 42 and the hydrophobic substrate 41 together form a "folded storage" structure. In the unpowered state, the multiple hydrophilic portions 42 are all hidden inside the insulating layer 40, arranged at intervals. In the powered state, the hydrophobic substrate 41 is stretched, and the multiple hydrophilic portions 42 are exposed and arranged at intervals.

[0084] In a specific embodiment, the hydrophobic substrate 41 has multiple slits 43 of varying depths on the side facing the ink 50. These slits 43 are spaced apart sequentially along a first direction X, and each slit 43 houses a hydrophilic portion 42. When energized, the insulating layer 40 is compressed and deformed, causing the multiple slits 43 to unfold, exposing the multiple hydrophilic portions 42 and exposing them to the outside environment. It should be noted that when the insulating layer 40 is fully unfolded, the hydrophilic portions 42 simply unfold from a folded state and do not exert shear force on the hydrophobic substrate 41, thus avoiding tearing after unfolding.

[0085] In some embodiments, the hydrophobic substrate 41 includes one or more of polydimethylsiloxane, fluorinated ethylene propylene copolymer, polychlorotrifluoroethylene, and fluororubber. Optionally, the contact angle of the hydrophobic substrate 41 can be 100° to 120°, specifically 100°, 105°, 110°, 115°, or 120°.

[0086] In some embodiments, the hydrophilic portion 42 includes one or more of silica, titanium dioxide, polyacrylic acid, and polyvinylpyrrolidone. Optionally, the contact angle of the hydrophilic portion 42 can be 0° to 30°, specifically 0°, 5°, 10°, 15°, 20°, 25°, or 30°.

[0087] In some embodiments, the thickness H1 of the hydrophobic substrate 41 is 500 nm to 1000 nm. Optionally, the thickness H1 of the hydrophobic substrate 41 can be 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, or 1000 nm.

[0088] In some embodiments, the thickness H2 of the hydrophilic portion 42 is 20 nm to 50 nm. Optionally, the thickness H2 of the hydrophilic portion 42 can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm.

[0089] For some implementation methods, please refer to Figure 8 The insulating layer 40 also includes a hardened portion 44, which is connected to the hydrophobic substrate 41, and a hydrophilic portion 42 is connected to the hardened portion 44. It should be noted that the hardened portion 44 is a portion of the hydrophobic substrate 41 obtained through a hardening process.

[0090] In some implementations, the electronic paper structure operates at a temperature of 70°C or less, which is considered a safe temperature for display. At this operating temperature, the first and second electrode layers can deform to form an arched bending effect without affecting the display; furthermore, this temperature will not damage other structural components.

[0091] In some implementations, the ambient temperature of the electronic paper structure is room temperature (e.g., 25°C) when it is not powered on; when it is powered on, the pixel driving voltage range of the electronic paper structure is 12V to 22V, and the temperature change range due to electrothermal heating is 0°C to 45°C, that is, the operating temperature of the electronic paper structure after being powered on can be less than or equal to 70°C.

[0092] In some embodiments, the present invention provides an electronic paper structure with a dual electrode layer length L of 200 μm, 600 μm, or 1200 μm, and a first electrode layer and a second electrode layer thickness H0 of 150 nm; wherein the first electrode layer is (Ni) and the second electrode layer is aluminum (Al). A driving voltage of 12V is applied to the electronic paper structure to make the operating temperature of the electronic paper structure 70°C, and the heating time (25°C to 70°C), cooling time (70°C to 25°C), and arch height are calculated.

[0093] In a specific embodiment, the temperature rise formulas for the first electrode layer and the second electrode layer are as follows (1)-(6):

[0094]

[0095] Q=mC×△T (4)

[0096] m = ρ m ×V (5)

[0097] V=W×L×H0 (6)

[0098] Where C is the specific heat capacity of the first electrode layer and the second electrode layer, C = 900 J / kg·K; ρ m ρ is the mass density of the first electrode layer and the second electrode layer. m =2700kg / m 3 L is the length of the double electrode layer, and W and L are set to be equal; H0 is the sum of the thicknesses of the first electrode layer and the second electrode layer.

[0099] In a specific embodiment, the arching height δ of the first electrode layer and the second electrode layer is calculated using the following formulas (7)-(8):

[0100]

[0101] Where a1 is the coefficient of thermal expansion of aluminum (26.1 × 10⁻⁶). -6 / K); a2 is the coefficient of thermal expansion of nickel (10×10). -6 / K); m is the thickness ratio of the second electrode layer (Al) to the first electrode layer (Ni); n is the Young's modulus ratio of the second electrode layer (Al) to the first electrode layer (Ni) (0.35).

[0102] Based on the above formulas (1)-(8), the heating time, cooling time and arching height of the electronic paper structure with double electrode layer lengths L of 200μm, 600μm and 1200μm can be obtained, as shown in Table 1 below.

[0103] Table 1

[0104] heating time 12ms 33ms 30ms Cooling time 14ms 27ms 36ms Arch height 15μm 43μm 86μm

[0105] As can be seen from Table 1, the heating and cooling time of the electronic paper structure provided by the present invention is 26ms to 66ms, while the response time of the conventional electrowetting electronic paper structure is 320ms to 1200ms. It can be clearly seen that by setting the first electrode layer, the second electrode layer, and the deformable insulating layer, the response rate of the electronic paper structure can be effectively improved.

[0106] [Methods for fabricating electronic paper structures]

[0107] In some embodiments, the present invention provides a method for manufacturing an electronic paper structure. The method for manufacturing an electronic paper structure is used to manufacture the electronic paper structure provided in the above embodiments. The method includes: sequentially disposing a first electrode layer, a second electrode layer, and an insulating layer on a first substrate.

[0108] For some implementation methods, please refer to Figure 8 and Figure 9The present invention specifically provides a method for manufacturing an insulating layer, which includes the following steps:

[0109] Step S10: Provide a hydrophobic substrate and pre-stretch the hydrophobic substrate to elongate it.

[0110] Step S20: A hydrophilic portion is provided on the surface of the pre-stretched hydrophobic substrate, and stress is released on the pre-stretched hydrophobic substrate with the hydrophilic portion to cause the hydrophobic substrate to shrink and obtain an insulating layer.

[0111] The method for manufacturing an insulating layer provided by the present invention utilizes the deformation capability of the hydrophobic substrate to create a hydrophilic portion on the hydrophobic substrate, and hides the hydrophilic portion within the hydrophobic substrate after the hydrophobic substrate shrinks; thus achieving the effect that the insulating layer has the ability to deform and switch between oleophilic and hydrophobic properties.

[0112] In some embodiments, in step S10, the material of the hydrophobic substrate includes one or more of polydimethylsiloxane, fluorinated ethylene propylene copolymer, polychlorotrifluoroethylene, and fluororubber.

[0113] In some embodiments, in step S10, the hydrophobic substrate is pre-stretched, and the elongation of the pre-stretched hydrophobic substrate is 150% to 300%. Optionally, the elongation of the pre-stretched hydrophobic substrate can be 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, or 300%.

[0114] In some embodiments, in step S10, the hydrophobic substrate is pre-stretched at a rate of 2 μm / s to 5 μm / s. Optionally, the rate of pre-stretching the hydrophobic substrate can be 2 μm / s, 2.5 μm / s, 3 μm / s, 3.5 μm / s, 4 μm / s, 4.5 μm / s, or 5 μm / s.

[0115] In some embodiments, in step S10, the thickness of the hydrophobic substrate before and after stretching is 500 nm to 1000 nm. Optionally, the thickness of the hydrophobic substrate before and after stretching can be 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, or 1000 nm.

[0116] For some implementation methods, please refer to Figure 10 In step S20, a hydrophilic portion is formed on the surface of the pre-stretched hydrophobic substrate, specifically including:

[0117] Step S21: Perform local hardening treatment on the surface of the pre-stretched hydrophobic substrate so that the surface of the pre-stretched hydrophobic substrate has a hardened part.

[0118] Step S22: A hydrophilic part is provided on the hardened part.

[0119] Step S23: Stress relief is performed on the pre-stretched hydrophobic substrate with hydrophilic portion to cause the hydrophobic substrate to shrink.

[0120] In some embodiments, the method for locally hardening the pre-stretched hydrophobic substrate surface in step S21 includes plasma treatment, chemical treatment, and phototreatment. In a specific embodiment, taking polydimethylsiloxane (PDMS) as a hydrophobic substrate as an example, oxygen plasma can be used to harden the PDMS surface.

[0121] In some embodiments, in step S21, the surface of the pre-stretched hydrophobic substrate (the side facing away from the first substrate) has a hardened portion, the thickness of which can be 20 nm to 50 nm. Optionally, the thickness of the hardened portion can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm. It should be noted that in the electronic paper structure, the surface of the hydrophobic substrate also has a hardened portion, and the hydrophilic portion is connected to the hardened portion.

[0122] In some embodiments, in step S22, a hydrophilic material is coated at intervals onto the hardened portion, forming a hydrophilic portion. The hydrophilic material includes one or more of silicon dioxide, titanium dioxide, polyacrylic acid, and polyvinylpyrrolidone. The thickness of the hydrophilic portion after coating is 20 nm to 50 nm. Optionally, the thickness of the hydrophilic portion after coating can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm.

[0123] In some embodiments, in step S23, after the hydrophilic portion is formed, the stress is slowly released to cause the hydrophobic substrate to shrink. To ensure the stability of the insulating layer, the release rate is ≤1 μm / s. It is understood that during the release process, the softer areas inside the hydrophobic substrate will attempt to shrink, but the surface hardened portion will prevent it from fully recovering, causing the surface of the hydrophobic substrate to buckle and become unstable, thereby forming a regular or irregular "folded storage" structure.

[0124] Electronic paper

[0125] In some embodiments, the present invention also provides an electronic paper, which includes the electronic paper structure provided in the above embodiments; or, the electronic paper includes an electronic paper structure manufactured by the method for manufacturing the electronic paper structure provided in the above embodiments.

[0126] In the description of the embodiments of this application, it should be noted that the orientation or positional relationship of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indicators are based on the orientation or positional relationship of the drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0127] It should be noted that the limitations on each step involved in this solution are not considered as limiting the order of steps, provided that they do not affect the implementation of the specific solution. The steps listed first can be executed first, later, or even simultaneously. As long as this solution can be implemented, it should be considered to fall within the scope of protection of this application.

[0128] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art will understand that all or part of the processes for implementing the above embodiments and equivalent variations made in accordance with the claims of this application are still within the scope of this application.

Claims

1. An electronic paper structure, characterized in that, The electronic paper structure includes a first substrate, a first electrode layer, a second electrode layer, and an insulating layer, all stacked together. The insulating layer has ink and a conductive liquid disposed on the side facing away from the second electrode layer. The coefficient of thermal expansion of the second electrode layer is greater than that of the first electrode layer. When the electronic paper structure is powered on, the first electrode layer and the second electrode layer protrude in a direction away from the first substrate.

2. The electronic paper structure according to claim 1, characterized in that, Along the first direction, the first electrode layer has a structure that is thin in the middle and thick at both ends; the second electrode layer has a structure that is thick in the middle and thin at both ends, and the first direction intersects with the thickness direction of the electronic paper structure.

3. The electronic paper structure according to claim 2, characterized in that, The sum of the thicknesses of the first electrode layer and the second electrode layer is H0. Along the first direction, the first electrode layer includes a first thickness region, a second thickness region, and a third thickness region connected in sequence. The first thickness region is located in the middle of the first electrode layer. The thickness of the first thickness region is 0.1H0 to 0.5H0, the thickness of the second thickness region is 0.25H0 to 0.75H0, and the thickness of the third thickness region is 0.5H0 to 0.9H0.

4. The electronic paper structure according to claim 3, characterized in that, The thickness and H0 of the first electrode layer and the second electrode layer are 80nm to 200nm; along the first direction, the length L of the first electrode layer and / or the second electrode layer is 200μm to 1200μm.

5. The electronic paper structure according to any one of claims 1-4, characterized in that, The insulating layer includes a hydrophobic substrate and a hydrophilic portion. The hydrophobic substrate is connected to the second electrode layer. The hydrophobic substrate is deformable. The hydrophilic portion is located on the side of the hydrophobic substrate facing away from the second electrode layer. The insulating layer includes a hydrophobic state and a hydrophilic state. In the hydrophobic state, the hydrophilic portion is embedded inside the hydrophobic substrate. In the hydrophilic state, the hydrophobic substrate is deformed, and the hydrophilic portion is exposed to the conductive liquid.

6. The electronic paper structure according to claim 5, characterized in that, The number of hydrophilic parts is multiple, and the multiple hydrophilic parts are arranged at intervals along a first direction, which intersects with the thickness direction of the electronic paper structure.

7. A method for fabricating an electronic paper structure, characterized in that, The method for manufacturing the electronic paper structure is used to manufacture the electronic paper structure as described in any one of claims 1-6, the method comprising: The first electrode layer, the second electrode layer, and the insulating layer are sequentially disposed on the first substrate.

8. The manufacturing method according to claim 7, characterized in that, The method for manufacturing the insulating layer includes: A hydrophobic substrate is provided, and the hydrophobic substrate is pre-stretched to elongate the hydrophobic substrate. A hydrophilic portion is provided on the surface of the pre-stretched hydrophobic substrate, and stress is released on the pre-stretched hydrophobic substrate with the hydrophilic portion to cause the hydrophobic substrate to shrink, thereby obtaining the insulating layer. The insulating layer includes a hydrophobic state and a hydrophilic state. In the hydrophobic state, the hydrophilic portion is embedded inside the hydrophobic substrate. In the hydrophilic state, the hydrophobic substrate is deformed, and the hydrophilic portion is exposed to the conductive liquid.

9. The manufacturing method according to claim 8, characterized in that, The hydrophobic substrate is pre-stretched, and the elongation of the pre-stretched hydrophobic substrate is 150% to 300%; and / or, the hydrophobic substrate is pre-stretched at a rate of 2 μm / s to 5 μm / s.

10. The manufacturing method according to claim 8, characterized in that, A hydrophilic portion is provided on the surface of the pre-stretched hydrophobic substrate, including: The surface of the pre-stretched hydrophobic substrate is locally hardened so that the surface of the pre-stretched hydrophobic substrate has a hardened portion. The hydrophilic portion is provided on the hardened portion.

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