Writable electronic device

Abstract

The invention provides a writable electronic device. The writable electronic device comprises a flexible base layer and an anti-dazzle texture layer on the outer surface of the flexible base layer. The flexible base layer has micro-elasticity, when the writing pen writes on the writing surface, a moving micro-recess can be generated under the pressure of the pen tip end of the writing pen and can be recovered along with the separation of the pen tip end, and the paper-like writing experience feeling is improved; the anti-dazzle texture layer is arranged, anti-dazzle textures are selected, and the friction degree of the writing face can be adjusted, so that the dynamic friction coefficient mu between the pen tip end and the writing face and the water contact angle theta of the writing face meet specific conditions, when mu and theta meet the specific conditions, the writing pen can meet the writing requirement and habit when writing on the writing face, and the writing effect is improved. The ink has moderate damping, is not too slippery or too astringent, and is not easy to block, so that the writing experience is close to the smooth feeling of paper-like writing.

Description

Technical Field

[0001] The present invention relates to the technical field of writable electronic equipment, and in particular to a writable electronic equipment. Background Art

[0002] With the development of information technology, writable electronic devices are widely used. Taking the ink screen office notebook as an example, a writable electronic device is an electronic writing board or electronic paper made with electronic ink technology, which can meet the user's habit of writing paper documents and has digital functions. When using an electromagnetic pen to write on it, you can write and erase like paper, and at the same time you can save the content or transfer it to a computer or mobile device, which is friendly to the eyes and the environment. With its unique writing feel, high-definition display effect, and portability and ease of use, the ink screen writing notebook has become one of the indispensable tools for more and more people in office, study and life.

[0003] However, the writable electronic devices currently on the market that focus on paper-like writing either have large writing resistance and a rough feeling during the writing process, or the writing is too smooth, making it difficult to achieve paper-like writing and erasing. Summary of the invention

[0004] Based on this, the present invention provides a writable electronic device that can simulate paper-like writing and erasing, thereby improving the paper-like writing experience.

[0005] A writable electronic device, comprising:

[0006] Display motherboard;

[0007] A writing film, the writing film comprising a flexible base layer and an anti-glare texture layer located on the outer surface of the flexible base layer, the flexible base layer is attached to the display surface of the display main board, the side of the anti-glare texture layer facing away from the flexible base layer is a writing surface, and the water contact angle θ of the writing surface satisfies: 95°≤θ≤115°; and

[0008] A writing pen, the writing pen is used to act on the writing surface and write on the writing surface, and the dynamic friction coefficient μ between the tip of the writing pen and the writing surface satisfies: 0.25μs≤μ≤0.5μs.

[0009] In one embodiment, the water contact angle θ of the writing surface and the dynamic friction coefficient μ between the tip of the writing pen and the writing surface satisfy: 102°≤θ≤109°, 0.3μs≤μ≤0.4μs.

[0010] In one embodiment, the roughness of the writing surface satisfies one or more of the following conditions:

[0011] (1) The arithmetic mean deviation Ra of the profile satisfies: 0.9 μm ≤ Ra ≤ 1.1 μm;

[0012] (2) The average width RSm of the contour unit satisfies: 120 μm ≤ Rsm ≤ 150 μm;

[0013] (3) The maximum profile peak height Rp satisfies: 3.3μm≤Rp≤4.6μm.

[0014] In one embodiment, the anti-glare texture layer satisfies one or more of the following conditions:

[0015] (1) The anti-glare texture layer is a UV-curable adhesive layer;

[0016] (2) The thickness of the anti-glare texture layer is 10 μm to 25 μm.

[0017] In one embodiment, the flexible base layer satisfies one or more of the following conditions:

[0018] (1) The material of the flexible base layer is polyethylene terephthalate;

[0019] (2) The thickness of the flexible base layer is 70 μm to 80 μm.

[0020] In one embodiment, the material of the pen tip of the writing pen includes polyoxymethylene resin, crystalline polyamide resin and rubber elastomer.

[0021] In one embodiment, one or more of the following conditions are met:

[0022] (1) The mass ratio of the polyoxymethylene resin, the crystalline polyamide resin and the rubber elastic body is (60-90): (1-20): (5-20);

[0023] (2) The polyoxymethylene resin is one or more selected from homopolymer polyoxymethylene resin and copolymer polyoxymethylene resin;

[0024] (3) The crystalline polyamide resin is selected from one or more of PA6, PA66, PA46 and PA having 10 or more methylene groups between adjacent amide bonds in the main chain;

[0025] (4) The rubber elastic body is selected from one or more of polyurethane elastomer, nitrile rubber, silicone rubber and ethylene propylene rubber.

[0026] In one embodiment, the material of the tip of the writing pen further includes porous graphite and / or hollow microspheres.

[0027] In one embodiment, one or more of the following conditions are met:

[0028] (1) The mass ratio of the polyoxymethylene to the porous graphite is (60-90):(1-30);

[0029] (2) The mass ratio of the polyoxymethylene to the hollow microspheres is (60-90):(1-30);

[0030] (3) The median particle size D50 of the porous graphite is 10 μm to 100 μm;

[0031] (4) The median particle size D50 of the hollow microspheres is 10 μm to 100 μm.

[0032] In one embodiment, the material of the pen tip of the writing pen also includes an antioxidant and / or a lubricant.

[0033] In one embodiment, one or more of the following conditions are met:

[0034] (1) The mass ratio of the polyoxymethylene to the antioxidant is (60-90): (0.2-10);

[0035] (2) The mass ratio of the polyoxymethylene to the lubricant is (60-90): (0.1-5);

[0036] (3) The antioxidant is selected from one or more of hindered phenol antioxidants and phosphite antioxidants;

[0037] (4) The lubricant is selected from one or more of polyol ester lubricants, silicone lubricants and stearic acid lubricants.

[0038] In one embodiment, the surface of the tip of the writing pen in contact with the writing surface is a spherical surface.

[0039] In one embodiment, the writing film further includes an optical adhesive layer, and the flexible base layer is bonded to the display surface of the display main board via the optical adhesive layer.

[0040] In one embodiment, the thickness of the optical adhesive layer is 20 μm to 30 μm.

[0041] In one embodiment, the display screen mainboard is an electronic ink display screen.

[0042] Compared with the traditional solution, the present invention has the following beneficial effects:

[0043] The writable electronic device of the present invention includes a flexible base layer and an anti-glare texture layer on the outer surface of the flexible base layer. On the one hand, the flexible base layer has micro-elasticity. When the writing pen writes on the writing surface, it can produce a moving micro-depression under the pressure of the pen tip of the writing pen, and recover as the pen tip leaves, thereby improving the paper-like writing experience; on the other hand, an anti-glare texture layer is provided. After research, the inventor found that the anti-glare texture is selected so that the dynamic friction coefficient μ between the pen tip and the writing surface and the water contact angle θ of the writing surface meet specific conditions. When μ and θ meet: 95°≤θ≤115° and 0.25μs≤μ≤0.5μs, the writing pen can meet the needs and habits of writing when writing on the writing surface, and has moderate damping, is not too slippery, not too astringent, and is not easy to get stuck, so that the writing experience is close to the smooth feeling of paper-like writing; on the other hand, the method for forming the anti-glare texture layer is very mature and reliable, which can achieve high-quality and high-precision production, and is not easy to fall off and wear after formation, and can maintain the writing quality for a long time. In summary, the writable electronic device of the present invention has a very good paper-like writing experience, can improve the actual paper-like writing experience of the writable electronic device, and is conducive to improving user satisfaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention and to more completely understand the present invention and its beneficial effects, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0045] Figure 1 It is a schematic diagram of an exploded structure of a writable electronic device according to one embodiment;

[0046] Figure 2 A schematic diagram of the structure of a writable electronic device in use according to an embodiment;

[0047] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure of the A-A' section;

[0048] Figure 4 A schematic diagram showing the structure of the mainboard;

[0049] Figure 5 It is a schematic diagram of the structure of the writing film;

[0050] Figure 6 It is a structural schematic diagram of a writing pen;

[0051] Figure 7 It is a schematic diagram of the structure of the pen holder;

[0052] Figure 8 It is a structural schematic diagram of the refill module;

[0053] Fig. 9 It is a schematic diagram of a writing pen writing on a writing surface.

[0054] Description of reference numerals:

[0055] 01. Writable electronic device; 1. Display main board; 11. LCD screen; 12. Touch panel; 13. Cover plate; 2. Writing film; 21. Flexible base layer; 22. Anti-glare texture layer; 23. Optical adhesive layer; 24. Inner surface protection layer; 25. Outer surface protection layer; 3. Writing pen; 31. Pen holder; 32. Pen core module; 321. Pen tip. DETAILED DESCRIPTION

[0056] The present invention will be further described in detail below in conjunction with specific embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0058] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0059] In the present invention, "plurality", "multiple", "multiple times", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0060] In the present invention, "optionally", "optional" and "optional" refer to optional, that is, to any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0061] In the present invention, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0062] In the present invention, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the optional numerical distribution within the above numerical interval is deemed to be continuous and includes the two numerical endpoints of the numerical range (i.e., the minimum value and the maximum value), and every numerical value between the two numerical endpoints.

[0063] In the present invention, when it comes to temperature parameters, unless otherwise specified, both constant temperature treatment and fluctuation within a certain temperature range are allowed. It should be understood that constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0064] In the present invention, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0065] In the present invention, when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may also be an element in the middle. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an element in the middle at the same time. It should also be understood that when explaining the connection relationship or positional relationship of the elements, although not explicitly described, the connection relationship and positional relationship are interpreted as including an error range, which should be within the acceptable deviation range of the specific value determined by those skilled in the art.

[0066] Taking the ink screen as an example of a writable electronic device, the ink screen generally includes a writing pen and a display mainboard. The writing pen and the display mainboard are both provided with corresponding electromagnetic modules. The writing pen and the display mainboard interact with each other to present the writing handwriting on the display mainboard. Specifically, the display mainboard is the main part used for display in the ink screen office book. The writing pen can be an electromagnetic pen. The electromagnetic pen can be an active electromagnetic pen or a passive electromagnetic pen. During use, the writing pen emits an electromagnetic signal to interact with the electromagnetic induction board of the display mainboard. When the writing pen is close to the display mainboard, the electromagnetic induction board will sense the electromagnetic signal of the writing pen, so that the induction line of the electromagnetic induction board will change, and then the display mainboard part will appear black or white to realize the writing function.

[0067] The paper-like writing function of the ink screen has always been the core selling point pursued by ink screen manufacturers. The ink screen has a paper-like writing function, which means that users can have the experience of writing on paper when using the ink screen. The handwriting is smooth and natural, and at the same time it has the advantages of digitalization, making documents easier to save and share.

[0068] For ink screens, to achieve paper-like writing, it is necessary to consider the pen tip design and writing cover design. The electromagnetic pen tip needs to simulate the writing feeling of paper and pen, and the appropriate pen tip material and shape need to be selected. Commonly used materials are hard plastic and metal materials, and the shape is usually conical or tapered to simulate the sharpness of paper and pen. The writing cover needs to match the electromagnetic pen tip to simulate the feeling of writing on paper. The writing cover is usually required to have a smooth and flat surface, with a color and reflectivity similar to that of paper, and a certain degree of anti-friction performance to avoid discomfort caused by friction.

[0069] However, the writing experience of traditional ink screen office notebooks with paper-like writing functions is very poor in actual use, mainly due to the limited material and craftsmanship of the pen tip and the writing cover. Traditional pen tip materials are mainly felt and pure POM (polyformaldehyde). The main disadvantages of felt pen tips are large damping and poor wear resistance, and the main disadvantages of pure POM pen tips are too hard and too slippery.

[0070] Traditional writing cover materials mainly include composite cover and tempered glass cover. The surface material of the composite cover is PMMA (polymethyl methacrylate). Although this material is very hard, it is also very brittle. During the preparation process of the composite cover, when the UV glue is hardened, if the surface AG value is increased by adding too much glue and increasing the curing time, the surface is prone to cracking due to the increase in energy. At the same time, the glue will shrink when curing, causing the generation of tension and cracking. Therefore, the surface AG value of the composite cover cannot be increased, which will make the composite cover relatively slippery. For tempered glass cover, the main disadvantage of the tempered glass cover is that the surface is too hard. After adding etching AG, there will be a sense of astringency when writing on the surface. It can be seen that the combination of the above schemes cannot achieve a good paper-like writing experience.

[0071] Based on this, after a series of studies, the inventor proposed a writable electronic device, which covers a writing film on the display motherboard. The writing film includes a flexible base layer and an anti-glare texture layer on the outer surface of the flexible base layer. The flexible base layer has micro-elasticity. When the writing pen writes on the writing surface, it can produce a moving micro-depression under the pressure of the pen tip, and recover as the pen tip leaves, improving the paper-like writing experience; in addition, the writing film is also provided with an anti-glare texture layer, the function of which is to avoid glare caused by excessive brightness of the display motherboard. After research, the inventor found that by selecting the anti-glare texture, the friction of the writing surface can be adjusted, so that the dynamic friction coefficient μ between the pen tip and the writing surface and the water contact angle θ of the writing surface meet specific conditions.

[0072] The inventor found that when 95°≤θ≤115° and 0.25μs≤μ≤0.5μs, the writing pen can meet the needs and habits of writing when writing on the writing surface, with moderate damping, not too slippery, not too astringent, and not easy to get stuck, making the writing experience close to the smoothness of paper-like writing. At the same time, the method for forming the anti-glare texture layer is very mature and reliable, and can achieve high-quality and high-precision production. It is not easy to fall and wear after formation, and can maintain the writing quality for a long time. In summary, the writable electronic device of the present invention has a good paper-like writing experience, can improve the actual experience of paper-like writing of the writable electronic device, and is conducive to improving user satisfaction.

[0073] The following will describe the specific optional implementation methods of the writable electronic device in conjunction with specific embodiments.

[0074] See also Figure 1 In one embodiment, the writable electronic device 01 includes a display mainboard 1, a writing film 2 and a writing pen 3. In the use state, please refer to Figure 2 and Figure 3 The writing film 2 covers the display main board 1, and the writing pen 3 writes on the outer surface of the writing film 2. It can be understood that the writing film 2 can be made of a light-transmitting material.

[0075] See also Figure 4 The display main board 1 includes a liquid crystal screen 11, a touch panel 12 located on the outer surface of the liquid crystal screen 11, and a cover plate 13 located on the outer surface of the touch panel 12. The writing film 2 can be located on the outer surface of the cover plate 13. The pressure sensitivity parameters on the touch panel 12 can be adjusted to adjust the thickness of the strokes and the ink concentration, which can better simulate the feeling of writing on paper.

[0076] See also Figure 4 and 5The writing film 2 includes a flexible base layer 21 and an anti-glare texture layer 22 located on the outer surface of the flexible base layer 21. The flexible base layer 21 is attached to the display surface of the display main board 1. Specifically, the flexible base layer 21 is attached to the cover plate 13, and the side of the anti-glare texture layer 22 away from the flexible base layer 21 is the writing surface. Figure 6 , Figure 7 and Figure 8 The writing pen 3 includes a pen body 31 and a core module 32. The core module 32 is located inside the pen body 31. One end of the core module 32 extending outside the pen body 31 is a pen tip 321. The pen tip 321 is used for writing on the writing surface.

[0077] In this embodiment, the dynamic friction coefficient μ between the pen tip 321 and the writing surface satisfies: 0.25μs≤μ≤0.5μs;

[0078] The water contact angle θ of the outer surface of the writing film 2 satisfies: 95°≤θ≤115°.

[0079] Alternatively, μ may be 0.25 μs, 0.3 μs, 0.4 μs, or 0.5 μs.

[0080] Alternatively, θ may be 95°, 100°, 105°, 110°, or 115°.

[0081] The writable electronic device 01 of this embodiment includes a writing film 2, which includes a flexible base layer 21 and an anti-glare texture layer 22 on the outer surface of the flexible base layer 21. In the first aspect, the flexible base layer 21 has a slight elasticity, see Fig. 9 When the writing pen 3 writes on the writing surface, a moving micro-depression can be generated under the pressure of the pen tip 321 of the writing pen 3 (see Fig. 9 A), and recovers as the pen tip 321 leaves (see Fig. 9 B), improve the paper-like writing experience; secondly, an anti-glare texture layer 22 is provided. After research, the inventor found that the anti-glare texture is selected so that the dynamic friction coefficient μ between the pen tip 321 and the writing surface and the water contact angle θ of the writing surface meet specific conditions. When μ and θ meet specific conditions, the writing pen 3 can meet the needs and habits of writing when writing on the writing surface, with moderate damping, not too slippery, not too astringent, and not easy to get stuck, so that the writing experience is close to the smooth feeling of paper-like writing; thirdly, the method for forming the anti-glare texture layer 22 is very mature and reliable, and can achieve high-quality and high-precision production. After formation, it is not easy to fall and wear, and can maintain the writing quality for a long time. In summary, the writable electronic device of this embodiment has a good paper-like writing experience, can improve the actual experience of paper-like writing of the writable electronic device 01, and is conducive to improving user satisfaction.

[0082] In some embodiments, the dynamic friction coefficient μ between the tip 321 of the writing pen 3 and the writing surface and the water contact angle θ of the writing surface satisfy: 102°≤θ≤109°, 0.3μs≤μ≤0.4μs, and the writing feels smoother at this time.

[0083] It should be noted that the water contact angle refers to the contact angle formed by a water drop on a solid surface, which reflects the interaction force between a liquid and a solid. The inventors have found that the size of the water contact angle on the surface of the writing film 2 will affect the writing effect. When the water contact angle θ of the writing surface is less than 95°, the friction between the finger or the pen tip 321 and the writing film 2 is large when writing, the writing fluency is low, and the hand feel is astringent. When the water contact angle θ of the writing surface is greater than 115°, the friction between the finger or the pen tip 321 and the writing film 2 is small when writing, the writing fluency is too high, and the hand feel is slippery. For the writing film 2, both smaller and larger water contact angles are not conducive to the writing effect. After multiple experiments, it has been verified that when the water contact angle of the writing film 2 is 102°≤θ≤109° and the dynamic friction coefficient μ between the pen tip 321 of the writing pen 3 and the writing surface is 0.3μs≤μ≤0.4μs, the writing smoothness is best.

[0084] The roughness of the writing surface is also related to the actual experience of paper-like writing. Optionally, in some embodiments, the roughness of the writing surface satisfies one or more of the following conditions:

[0085] (1) The arithmetic mean deviation Ra of the profile satisfies: 0.9 μm ≤ Ra ≤ 1.1 μm. For example, Ra may be 0.9 μm, 1.0 μm, or 1.1 μm.

[0086] (2) The average width RSm of the contour unit satisfies: 120 μm ≤ Rsm ≤ 150 μm; for example, RSm can be 120 μm, 130 μm, 140 μm, or 150 μm.

[0087] (3) The maximum profile peak height Rp satisfies: 3.3 μm ≤ Rp ≤ 4.6 μm. For example, Rp can be 3.3 μm, 4 μm, or 4.6 μm.

[0088] After a series of studies, the inventors found that the values ​​of the roughness parameters (Ra, Rsm, Rp) of the writing surface will affect the writing effect.

[0089] For the Ra (average roughness) value, the smaller the Ra value, the smoother the surface; the larger the Ra value, the rougher the surface. As for the writing effect, the inventor found through a series of studies that when 0.9 μm ≤ Ra ≤ 1.1 μm is within this range, it helps to reduce the friction resistance between the finger or pen tip 321 and the writing film 2, making writing smoother, and can also reduce the shaking of the finger or pen tip 321 during the writing process, thereby improving the accuracy of writing.

[0090] For the Rsm (maximum peak distance) value, the larger the Rsm value, the greater the undulation of the surface. For the writing effect, a larger Rsm value may cause the finger or pen tip 321 to encounter greater resistance and an uneven feeling on the surface, affecting the fluency and comfort of writing. In addition, a larger Rsm value may also increase the noise and vibration during writing and reduce the accuracy of writing. After a series of studies, the inventor found that when 120μm≤Rsm≤150μm is within this range, it helps to reduce the friction resistance between the finger or pen tip 321 and the writing film 2, making writing smoother, while also reducing the noise and vibration during writing and improving the accuracy of writing.

[0091] For the Rsm (maximum peak distance) value, the Rp value represents the height of the highest peak on the surface. A larger Rp value may cause instability during writing, because the finger or pen tip 321 may have obvious jitter or sliding on the peak, which will affect the accuracy and stability of writing. After a series of studies, the inventor found that when 3.3μm≤Rp≤4.6μm is within this range, writing jitter and sliding can be reduced, and writing accuracy and stability can be improved.

[0092] It should be pointed out that in the present invention, reference is made to GB / T 3505-2000 "Terms, definitions and parameters of surface structure of product geometric technical specifications surface structure profile method". The arithmetic mean deviation Ra of the profile is defined as the arithmetic mean of the absolute value of the ordinate Z(x) within a sampling length. The average width RSm of the profile unit is defined as the average value of the profile unit width Xs within a sampling length. The maximum profile peak height Rp is defined as the maximum profile peak height Zp within a sampling length.

[0093] Optionally, in some embodiments, the anti-glare texture layer 22 is a UV curing adhesive layer. UV curing adhesive (UV adhesive) can be coated in a preset texture mold, and the anti-glare texture layer 22 can be formed by photocuring. Compared with etching the anti-glare texture on the glass cover 13, forming the UV curing adhesive layer by photocuring is conducive to improving the writing roughness.

[0094] Optionally, the anti-glare texture layer 22 has a thickness of 10 μm to 25 μm, for example, 10 μm, 15 μm, 20 μm, or 25 μm.

[0095] For the anti-glare texture layer 22, if the thickness of the anti-glare texture layer 22 is too thick, it will affect the surface uniformity of the anti-glare texture layer 22 and increase the curing time, resulting in an increase in production costs. At the same time, the substrate is easily deformed due to the shrinkage of the glue during curing. However, if the thickness of the anti-glare texture layer 22 is too thin, because of the need to balance the hardness requirements, the UV layer is too thin to reach the pencil hardness of 3H. After a series of studies, the inventor found that when the thickness of the anti-glare texture layer 22 is 10μm to 25μm, the surface of the anti-glare texture layer 22 is relatively uniform, while meeting the writing requirements of the writable electronic device 01.

[0096] Optionally, the material of the flexible base layer 21 is polyethylene terephthalate (PET). Compared with a polycarbonate (PC) / polymethyl methacrylate (PMMA) composite sheet, the anti-glare texture layer 22 formed on the flexible base layer 21 represented by PET is less prone to cracking, and the texture of the anti-glare texture layer 22 can be stably produced within a larger size range, which is beneficial to controlling the dynamic friction coefficient μ, the water contact angle θ, and the roughness.

[0097] In some embodiments, before the UV curing glue in the preset texture mold is photocured, the flexible base layer 21 may be placed on the UV curing glue and then photocured to form an anti-glare texture layer 22 on the flexible base layer 21 .

[0098] Optionally, the thickness of the flexible base layer 21 is 70 μm to 80 μm, for example, the thickness may be 70 μm, 75 μm, or 80 μm.

[0099] By selecting the material and thickness of the anti-glare texture layer 22 and the flexible base layer 21, a writing film 2 that matches the hardness of the writing pen 3 can be obtained, further improving the paper-like writing experience of the writable electronic device 01.

[0100] Please continue to see Figure 5 In this embodiment, the writing film 2 further includes an optical adhesive layer 23, and the flexible base layer 21 is bonded to the display surface of the display main board 1 through the optical adhesive layer 23. Thus, by providing the optical adhesive layer 23, the writing film 2 can be bonded to the display surface of the display main board 1.

[0101] Optionally, the thickness of the optical adhesive layer 23 is 20 μm to 30 μm. For example, the thickness may be 20 μm, 25 μm, or 30 μm. The optical adhesive layer 23 may be an OCA (Optically Clear Adhesive) adhesive layer.

[0102] As for the optical adhesive layer 23, the inventor has found through repeated research that if the optical adhesive layer 23 is too thick, the writing pen 3 is prone to irreversible depression when writing, but if the optical adhesive layer 23 is too thin, the pasting effect will be greatly reduced and the writing feel will be affected. The inventor has found through repeated research that when the thickness of the optical adhesive layer 23 is 20 μm to 30 μm, it can ensure that the optical adhesive layer 23 can firmly fix the flexible base layer 21 on the display surface of the display mainboard 1, and will not cause irreversible depression on the flexible base layer 21 when writing.

[0103] In some embodiments, the writing film 2 further includes an inner surface protective layer 24 and / or an outer surface protective layer 25. The inner surface protective layer 24 is located on the inner surface of the optical adhesive layer 23; the outer surface protective layer 25 is located on the outer surface of the anti-glare texture layer 22. In this embodiment, the writing film 2 further includes an inner surface protective layer 24 and an outer surface protective layer 25. The inner surface protective layer 24 is located on the inner surface of the OCA adhesive layer, and the material of the inner surface protective layer 24 can be polyethylene (PE), and the thickness can be 45μm to 55μm. The outer surface protective layer 25 is located on the outer surface of the anti-glare texture layer 22, and the material of the outer surface protective layer 25 can be PET, and the thickness can be 55μm to 65μm. The inner surface protective layer 24 and the outer surface protective layer 25 can be removed before the writing film 2 is officially used.

[0104] To better simulate the real pen and paper writing experience. Figure 8 In this embodiment, the surface where the tip 321 of the writing pen 3 contacts the outer surface of the writing film 2 is a spherical surface.

[0105] In order to match the above-mentioned writing film 2, the pen tip 321 of the writing pen 3 is required to have matching hardness, elasticity and excellent wear resistance, and the material of the pen tip 321 of the writing pen 3 can be selected. Optionally, the material of the pen tip 321 of the writing pen 3 includes polyoxymethylene (POM) resin, crystalline polyamide resin and rubber elastomer. Compared with the pen tip 321 of pure polyoxymethylene (POM) resin, the use of the above-mentioned material has hardness and elasticity matching the above-mentioned writing film 2. Compared with the felt pen tip, the above-mentioned material has good wear resistance. And there is a suitable dynamic friction coefficient between the above-mentioned material and the above-mentioned writing film 2, and the paper-like writing experience is good.

[0106] Among them, POM resin has a rigidity and hardness close to that of metal, good fatigue resistance, chemical resistance, and good self-lubricating and wear resistance. Optionally, the polyoxymethylene resin is one or more selected from homopolymer polyoxymethylene resin and copolymer polyoxymethylene resin.

[0107] The compatibility of crystalline polyamide resin with POM resin is poor. In this embodiment, it is dispersed in the POM resin in a spherical phase state. After crystallization, it is phase-separated from POM. There are gaps at the phase interface. These gaps have a sound-absorbing effect, which is beneficial to reduce the noise during writing. At the same time, polyamide is also a type of polymer with self-lubricating properties, which will not increase the friction coefficient of the system. Optionally, the crystalline polyamide resin is selected from one or more of PA6, PA66, PA46 and PA with more than 10 methylene groups between adjacent amide bonds in the main chain. Among them, the number of methylene groups between adjacent amide bonds in the main chain can be 11, 12, 14, 15, or 20.

[0108] The rubber elastic body can adjust the toughness of the system, so that the rigidity and toughness of the pen tip 321 of the writing pen 3 are balanced, and it is not easy to break or crack during use. Optionally, the rubber elastic body is selected from one or more of polyurethane elastomer, nitrile rubber, silicone rubber and ethylene propylene rubber.

[0109] Optionally, the mass ratio of polyoxymethylene resin, crystalline polyamide resin and rubber elastic body is (60-90):(1-20):(5-20), for example, 60:1:5, 60:10:15, 70:10:10, 70:3:15, 80:5:12, 80:15:10, 90:2:6, 90:20:20.

[0110] Further optionally, the mass ratio of the polyoxymethylene resin, the crystalline polyamide resin and the rubber elastic body is (65-90):(4-18):(8-20).

[0111] Optionally, the material of the pen tip 321 of the writing pen 3 also includes porous graphite and / or hollow microspheres. Both porous graphite and hollow microspheres can reduce the friction coefficient and have a certain sound absorption and noise reduction effect. Among them, adding porous graphite is more conducive to reducing the friction coefficient and having a better sound absorption and noise reduction effect than adding flake graphite.

[0112] Optionally, the mass ratio of polyoxymethylene to porous graphite is (60-90):(1-30), for example, 60:8, 70:10, 80:20, or 90:25.

[0113] Optionally, the median particle size D50 of the porous graphite is 10 μm to 100 μm, for example, 10 μm, 50 μm, or 100 μm.

[0114] Optionally, the mass ratio of polyoxymethylene to hollow microspheres is (60-90):(1-30), for example, 60:8, 70:10, 80:20, or 90:25.

[0115] Optionally, the median particle size D50 of the hollow microspheres is 10 μm to 100 μm, for example, 10 μm, 50 μm, or 100 μm.

[0116] Optionally, the material of the pen tip 321 of the writing pen 3 further includes an antioxidant and / or a lubricant. .

[0117] Optionally, the antioxidant is selected from one or more of hindered phenol antioxidants and phosphite antioxidants.

[0118] Among them, the model of the hindered phenol antioxidant can be antioxidant 1098, antioxidant 1010, and antioxidant 1076. The model of the phosphite antioxidant can be antioxidant 168 and antioxidant PEP36.

[0119] Optionally, the lubricant is selected from one or more of polyol ester lubricants, silicone lubricants and stearic acid lubricants.

[0120] The stearic acid lubricant may be pentaerythritol stearate (PETS).

[0121] Optionally, the mass ratio of polyoxymethylene to antioxidant is (60-90):(0.2-10), for example, 60:0.5, 70:2, 80:4, 90:10.

[0122] Optionally, the mass ratio of polyoxymethylene to lubricant is (60-90):(0.1-5), for example, 60:0.5, 70:1, 80:2, or 90:5.

[0123] In some examples, the material of the pen tip 321 of the writing pen 3 includes the following components in parts by weight:

[0124] 60-90 parts of polyoxymethylene resin, 1-20 parts of crystalline polyamide resin, 5-20 parts of rubber elastomer, 1-30 parts of porous graphite, 1-30 parts of hollow microspheres, 0.1-5 parts of hindered phenol antioxidant, 0.1-5 parts of phosphite antioxidant, and 0.1-5 parts of lubricant.

[0125] The above raw materials can be mixed, and the premixed material can be extruded to obtain a composite material, and then the composite material can be molded to obtain the pen tip 321 of the writing pen 3.

[0126] It is understood that the components can be mixed in a mixer to obtain a premix. The mixing conditions can be: stirring at 600 rpm to 1000 rpm for 1 min to 10 min, stirring at 100 rpm to 300 rpm for 1 min to 5 min, and discharging at 50 rpm to 100 rpm.

[0127] The mixed material can be melt-blended, extruded and granulated by a twin-screw extruder to obtain a composite material. The conditions for melt-blending, extrusion and granulation can be that the main speed of the extruder is 200 rpm to 500 rpm, and the temperature of each zone is controlled within a temperature range of 180° C. to 260° C.

[0128] The molding process can be performed by injection molding or compression molding.

[0129] In this embodiment, the writable electronic device 01 is an ink screen writing pad.

[0130] The ink screen writing book has the following advantages: 1. The characteristics of the electronic ink display make it suitable for indoor and outdoor environments. The text and graphics have a highly clear display effect, no backlight is required, will not cause fatigue to the human eye, protect the eyes, do not self-luminous, black and white display, and the color and reflectivity are similar to paper. 2. It can import text formats such as PDF, DOC, TXT or JPG, PNG, etc. from devices such as notebooks, computers and mobile phones. 3. Data in picture format can be annotated with a writing pen 3 to meet the work needs of different industries. 4. The ink screen writing book is light in size, easy to carry and store, and can achieve the purpose of transparent work, recording at any time and not missing any information. 5. The battery life of the ink screen writing book is long, generally it can be used for more than 1 to 2 weeks, and does not need to be charged frequently. 6. It can support multiple input methods such as voice, handwriting input and optical character recognition, making the user experience more convenient. In addition to the above advantages, the writable electronic device 01 of this embodiment also has the following advantages: the ink screen writing book and the writing pen 3 are highly compatible, the writing sensation is similar to that of paper and pen, the handwriting is smooth and natural, and very realistic, allowing users to enjoy the comfortable feeling of writing on paper.

[0131] The following is further described in conjunction with specific embodiments and comparative examples. The raw materials involved in the following specific embodiments and comparative examples, unless otherwise specified, can all be commercially available, the instruments used, unless otherwise specified, can all be commercially available, and the processes involved, unless otherwise specified, are all routinely selected by those skilled in the art.

[0132] Example 1

[0133] This embodiment provides a writable electronic device and a preparation method, the steps are as follows:

[0134] 1. Preparation method Writing film 2

[0135] Place the preset texture film on the machine, evenly apply liquid UV glue in the preset texture mold, then cover the liquid UV glue layer with a thickness of 75 μm on the PET base layer, and cure it under ultraviolet light. After curing, an anti-glare texture layer 22 with a thickness of 16 μm is formed on the PET base layer.

[0136] An OCA adhesive layer with a thickness of 25 μm was formed on the other side of the PET base layer to obtain a writing film 2.

[0137] 2. Preparation of writing pen 3

[0138] Referring to Table 1, each component was added to a mixer, stirred at 600 rpm for 3 min, stirred at 100 rpm for 2 min, and discharged at 50 rpm to obtain a premix. The premix was added to a twin-screw extruder, the main extruder speed was 300 rpm, the temperature of each zone was controlled within the temperature range of 180°C to 230°C, and the composite material was obtained by melt blending, extrusion and granulation. The composite material was injection molded to obtain a pen tip 321.

[0139] The pen core module 32 is prepared by using the pen tip 321 , and the pen core module 32 is installed into the pen body 31 to obtain the writing pen 3 .

[0140] Table 1

[0141]

[0142] The OCA adhesive layer of the writing film 2 was attached to the glass cover plate 13, and the adhesion between the writing film 2 and the glass cover plate 13 was tested according to the following method. The writing film 2 was also tested for haze, visible light transmittance, 60° glossiness, pencil hardness, friction resistance, chemical resistance, UV aging resistance, salt spray, hot and cold shock, high / low temperature storage, water contact angle, roughness, and the coefficient of dynamic friction between the writing pen 3 and the writing surface. The results are shown in Table 2. The wear resistance (life test), drop sound, writing sound, and ISO notched impact strength kJ / m of the writing pen 3 on the writing surface were tested according to the following method. 2 , drop resistance and pressure resistance, the results are shown in Table 3.

[0143] Among them, the test methods for each project are as follows:

[0144] Adhesion: Cross-cut 100 small grids (1×1mm) on the surface of the product, firmly stick 3M610# tape on the test part, and apply it with an eraser 5 times to make sure there are no bubbles between the tape and the tested part. Leave it for 90±30 seconds, hold one end of the tape and tear it off within 0.5 seconds in the opposite direction of 60 degrees.

[0145] 60° glossiness: a. Place the sample on a black flannel (glossiness is 0GU); use (Manufacturer model: CQ-380 (3301045) three-angle glossiness tester for testing; b. 60-degree angle reflection.

[0146] Pencil hardness: Use Mitsubishi 3H pencil (UNI series) at 45 degree angle, stroke: 40 mm, load: 750 g to draw 5 lines in different directions.

[0147] Steel wool friction: 1. Test method: Stick 20mm×20mm (steel wool model is #0000, manufacturer: Bon Star) steel wool on the friction head with double-sided tape, apply 500g weight, test frequency: 35-50 times / minute, stroke: 40mm, friction times 500 times and 1000 times.

[0148] Alcohol rubbing: Use a dust-free cloth (recommended model: TA9008) to saturate it with anhydrous alcohol (concentration ≥ 99.5%) and wrap it on the dedicated test head (the area of ​​the test head after wrapping with the dust-free cloth is about 1cm 2 ), apply a load of 500g, use a special instrument at a speed of 40 times / min to 50 times / min, stroke: 40mm (can be adjusted according to the product and the test area needs to be covered), wipe back and forth on the sample surface for 500 cycles and observe the sample for 1000 cycles.

[0149] Rubber friction: Use a special rubber (rubber model: ERASERREFILL7017R), apply a load of 500g, rub back and forth on the sample surface at a speed of 40 times / min to 60 times / min, and a stroke of 40mm. Observe the sample for 25 cycles and 50 cycles.

[0150] Chemical resistance test: a. Coca-Cola; b. Cosmetics; c. Lipstick; d. Vaseline; e. Sunscreen; f. Tomato juice

[0151] Before testing, record the color difference value, use cotton swabs to apply chemicals a to f on all visible surfaces, and leave them at room temperature for 8 hours. After 8 hours, use cotton cloth to clean the surface (rubbing force is 6-12N); follow the following 4 steps to clean:

[0152] (1) Wipe the surface with a dry cotton cloth and record the test results after 30 seconds. If it cannot be cleaned, proceed to step 2.

[0153] (2) Use a new cotton cloth dipped in clean water to wipe, and record the test results after 30 seconds. If it cannot be cleaned, proceed to step 3;

[0154] (3) Use a new cotton cloth dipped in detergent to wipe, and record the test results after 30 seconds. If it cannot be cleaned, proceed to step 4;

[0155] (4) Use a new cotton cloth dipped in 98% isopropyl alcohol to wipe the surface and record the surface condition after 30 seconds.

[0156] UV aging resistance test: Wrap one side of the sample with tin foil and record the color difference value. Use argon lamp testing equipment, with 20 hours of light and 4 hours of darkness as one cycle. One test cycle tests 6 cycles;

[0157] Lighting conditions: set the box temperature to 40℃, the blackboard temperature to 50℃, the humidity to 35%, the irradiance of the lamp at 340nm band to 0.63W / M2, and the wavelength range to 300-800nm; Dark conditions: set the temperature to 40℃ and the humidity to 50%.

[0158] Salt spray test: a. Record the color difference before and after the test; b. Salt solution 5% NaCl, PH: 6.5-7.2; c. Temperature: 35°C; d. Spray volume: 1.0-2.0 ml / 80 square / hour; e. Duration: 72 hours (3 cycles × 24 hours); f. 1 cycle: (2 hours spraying + 22 hours storage: 40°C, 95% RH).

[0159] Thermal shock test: a. Record the color difference before and after the test; b. TH (test temperature value): 80℃±2℃; c. TL (test temperature value): -40℃±2℃; d. tcl (stabilization time after temperature switching): <5 minutes; e. tc2 (temperature stabilization time of sample H): 0.5h; f. tc3 (temperature stabilization time of sample L): 0.5h; g. (number of cycles): 100 cycles.

[0160] High temperature storage test: a. Record the color difference before and after the test; b. Test temperature: 70℃: humidity: 90%; c. Holding time: 96H.

[0161] Low temperature storage test: a. Record the color difference before and after the test; b. Test temperature: -35℃; c. Holding time: 24H.

[0162] Roughness: Place the film comparison sheet on the test product and test it using a roughness tester (manufacturer model: PCE-RT2000).

[0163] Dynamic friction coefficient: a. Equipment: TL201Ts (Trinity-Lab); b. Pen angle: 45°; c. Load: 200 gf; d. Speed: 50 mm / sec; e. Measuring distance: 30 mm.

[0164] Micro drop test (pen core module 32): a. Normal temperature environment; b. Drop height 10 cm; c. Drop the pen tip 321 direction 100 times.

[0165] Writing sound: a. Normal temperature environment; b. Quiet silent room; c. Test equipment: decibel meter; d. Distance between equipment and test point: 30CM from pen tip to decibel meter; e. Writing force and angle: 2.5N force, 45° angle; f. Measuring distance: 30mm, 100mm / sec back and forth, 3 times in total.

[0166] Drop sound: The pen body is perpendicular to the writing surface, and the pen tip 32110cm drops vertically onto the writing surface attached to the glass cover plate 13.

[0167] The pen tip 321 marking life test: a. Normal temperature environment; b. Test 1: The pen body is perpendicular to the writing surface and a writing pressure of 2.5N is applied to the pen tip 321; Test 2: The pen body is at a 45° angle to the writing surface and a writing pressure of 2.5N is applied to the pen tip 321; The pen tip 321 draws a line on the front of the writing surface, and the total length is required to be 2KM; 20 to 30 back and forth strokes per minute.

[0168] The pen tip 321 click life test (conducted in series with the pen tip stroke life test): a. Normal temperature environment; b. The pen body is perpendicular to the writing surface and a 2.5N click pressure is applied to the pen tip 321; the pen tip 321 acts perpendicularly on the writing surface 4000 times; the click rate is 40 to 50 times / min.

[0169] Pen tip pressure resistance test: a. Normal temperature environment; b. With the pen tip vertically downward, press with a force of 1kgf for 5s, for a total of 5 times, with a 10s interval between each time; with the pen tip at 45 degrees downward, press with a force of 1kgf for 5s, for a total of 5 times, with a 10s interval between each time.

[0170] Table 2

[0171]

[0172]

[0173] Table 3

[0174]

[0175]

[0176] As can be seen from Table 2 and Table 3, in the writable electronic device 01 of this embodiment, the quality of the writing film 2 and the writing pen 3 can meet the requirements, and the wear resistance between the writing film 2 and the writing pen 3 is good, and the service life can be long. The dynamic friction coefficient μ between the tip 321 of the writing pen 3 and the writing surface is 0.36μs, and the water contact angle θ of the writing surface is 104°, which has moderate damping, is not too slippery, not too astringent, and is not easy to get stuck. At the same time, the writing sound is 30dB, which is close to the decibel produced by pencil writing on paper. The writing feeling is very close to the writing feeling of pencil on paper, and the paper-like writing experience is good.

[0177] Example 2 to Example 4, Comparative Example 1 to Comparative Example 4

[0178] Referring to Table 1 and the preparation method of Example 1, the components of the pen tip 321 of the writing pen 3 and the texture of the preset texture mold were changed to prepare the writable electronic devices of Examples 2 to 4 and Comparative Examples 1 to 2. Referring to Table 1 and the preparation method of Example 1, the texture of the preset texture mold was changed to prepare the writable electronic devices 01 of Comparative Examples 3 to 4. Referring to the test method of Example 1, the writing film 2 was tested for water contact angle and roughness, the dynamic friction coefficient between the writing pen 3 and the writing surface was tested, and the wear resistance (life test) and drop sound of the writing pen 3 on the writing surface were tested. The results are shown in Table 4.

[0179] Table 4

[0180]

[0181]

[0182] It can be seen from Table 4 that in the writable electronic devices of Examples 2 to 4, the writing sound has been tested to reach 18dB to 35dB, and the sound is highly similar to paper. The writing feeling of the writing pen 3 on the writing film 2 is very close to the writing feeling of a pencil on paper, and the subjective experience is good. The wear resistance between the writing film 2 and the writing pen 3 is good, and the service life can be long. Compared with Example 1, although the impact strength of Comparative Example 1 is higher without the addition of PA6, the falling sound reaches 42 decibels, and the handwriting sound is as loud as 49 decibels. This shows that PA6 is phase-separated and crystallized in the POM system, and a microscopic phase separation gap is generated at the phase interface, which has a certain sound absorption effect. Comparative Example 2 has an ISO impact strength of only 3.2kJ / m without the addition of polyurethane elastomer. 2, indicating that the elastomer can better improve the toughness of the system and achieve a balance between rigidity and toughness. At the same time, the texture of the preset texture mold of Comparative Examples 1 to Comparative Examples 4 is different from that of Examples 1 to 4. The roughness of the outer surface of the writing film, the dynamic friction coefficient μ between the tip 321 of the writing pen 3 and the writing surface, and the water contact angle θ of the writing surface have all changed, and the paper-like writing experience is worse than that of Examples 1 to 4.

[0183] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0184] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A writable electronic device, characterized in that: include: Display motherboard; A writing film, the writing film comprising a flexible base layer and an anti-glare texture layer located on the outer surface of the flexible base layer, the flexible base layer is attached to the display surface of the display main board, the side of the anti-glare texture layer facing away from the flexible base layer is a writing surface, and the water contact angle θ of the writing surface satisfies: 95°≤θ≤115°; and A writing pen, the writing pen is used to act on the writing surface and write on the writing surface, and the dynamic friction coefficient μ between the tip of the writing pen and the writing surface satisfies: 0.25μs≤μ≤0.5μs.

2. The writable electronic device according to claim 1, characterized in that: The water contact angle θ of the writing surface and the dynamic friction coefficient μ between the tip of the writing pen and the writing surface satisfy the following requirements: 102°≤θ≤109°, 0.3μs≤μ≤0.4μs.

3. The writable electronic device according to claim 1, characterized in that: The roughness of the writing surface satisfies one or more of the following conditions: (1) The arithmetic mean deviation Ra of the profile satisfies: 0.9 μm ≤ Ra ≤ 1.1 μm; (2) The average width RSm of the contour unit satisfies: 120 μm ≤ Rsm ≤ 150 μm; (3) The maximum profile peak height Rp satisfies: 3.3μm≤Rp≤4.6μm.

4. The writable electronic device according to any one of claims 1 to 3, characterized in that: The anti-glare texture layer meets one or more of the following conditions: (1) The anti-glare texture layer is a UV-curable adhesive layer; (2) The thickness of the anti-glare texture layer is 10 μm to 25 μm.

5. The writable electronic device according to any one of claims 1 to 3, characterized in that: The flexible base layer meets one or more of the following conditions: (1) The material of the flexible base layer is polyethylene terephthalate; (2) The thickness of the flexible base layer is 70 μm to 80 μm.

6. The writable electronic device according to any one of claims 1 to 3, characterized in that: The material of the pen tip of the writing pen includes polyoxymethylene resin, crystalline polyamide resin and rubber elastomer.

7. The writable electronic device according to claim 6, characterized in that: One or more of the following conditions are met: (1) The mass ratio of the polyoxymethylene resin, the crystalline polyamide resin and the rubber elastic body is (60-90): (1-20): (5-20); (2) The polyoxymethylene resin is one or more selected from homopolymer polyoxymethylene resin and copolymer polyoxymethylene resin; (3) The crystalline polyamide resin is selected from one or more of PA6, PA66, PA46 and PA having 10 or more methylene groups between adjacent amide bonds in the main chain; (4) The rubber elastic body is selected from one or more of polyurethane elastomer, nitrile rubber, silicone rubber and ethylene propylene rubber.

8. The writable electronic device according to claim 7, characterized in that: The material of the tip of the writing pen also includes porous graphite and / or hollow microspheres.

9. The writable electronic device according to claim 8, characterized in that: One or more of the following conditions are met: (1) The mass ratio of the polyoxymethylene to the porous graphite is (60-90):(1-30); (2) The mass ratio of the polyoxymethylene to the hollow microspheres is (60-90):(1-30); (3) The median particle size D50 of the porous graphite is 10 μm to 100 μm; (4) The median particle size D50 of the hollow microspheres is 10 μm to 100 μm.

10. The writable electronic device according to claim 6, characterized in that: The material of the pen tip of the writing pen also includes an antioxidant and / or a lubricant.

11. The writable electronic device according to claim 10, characterized in that: One or more of the following conditions are met: (1) The mass ratio of the polyoxymethylene to the antioxidant is (60-90): (0.2-10); (2) The mass ratio of the polyoxymethylene to the lubricant is (60-90): (0.1-5); (3) The antioxidant is selected from one or more of hindered phenol antioxidants and phosphite antioxidants; (4) The lubricant is selected from one or more of polyol ester lubricants, silicone lubricants and stearic acid lubricants.

12. The writable electronic device according to any one of claims 1 to 3, characterized in that: The surface where the tip of the writing pen contacts the writing surface is a spherical surface.

13. The writable electronic device according to any one of claims 1 to 3, characterized in that: The writing film further comprises an optical adhesive layer, and the flexible base layer is bonded to the display surface of the display main board via the optical adhesive layer.

14. The writable electronic device according to claim 13, characterized in that: The thickness of the optical adhesive layer is 20 μm to 30 μm.

15. The writable electronic device according to any one of claims 1 to 3, characterized in that: The display screen mainboard is an electronic ink display screen.

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