A lower substrate, an electrowetting display device and a manufacturing method of the lower substrate

Abstract

The application discloses a lower substrate, and discloses an electrowetting display device with the lower substrate and a manufacturing method for manufacturing the lower substrate, wherein the lower substrate comprises: a lower plate body, a side surface of which is provided with a first electrode; a convex part provided on the first electrode, the convex part being tapered in the height direction of the convex part; a hydrophobic insulation layer provided on the side of the first electrode close to the convex part and covering the convex part; and a pixel wall provided on the side of the hydrophobic insulation layer away from the first electrode, the pixel wall defining a plurality of pixel grids, and the convex part being arranged in each pixel grid. By arranging the tapered convex part in the pixel grid, the application can reduce the opening voltage required for ink rupture, improve the consistency of the ink shrinkage movement direction in each pixel grid, and improve the light characteristics of the display device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a lower substrate, an electrowetting display device and a manufacturing method of the lower substrate. BACKGROUND

[0002] In the electrowetting display, by changing the voltage applied between the liquid and the substrate electrode, the surface tension between the liquid and the solid in the pixel grid is changed, so that the ink in the pixel grid changes from the original spreading state to the shrinkage state, thereby realizing the functions of pixel switching and gray scale control.

[0003] In the prior art, the electrode of the substrate is provided with a pixel grid and a cylindrical protrusion, the cylindrical protrusion is located in the pixel grid, the thickness of the ink at the position of the cylindrical protrusion in the pixel grid is the thinnest, and when the electrode of the substrate is applied with voltage, the rupture position of the ink occurs preferentially at the thinnest position of the ink, so that the ink in the pixel grid changes from the original spreading state to the shrinkage state.

[0004] However, as the voltage increases, the rupture opening rate of the ink at the cylindrical protrusion has a mutation process and does not change with the increase of the voltage, so that the ink cannot be directed to shrinkage movement, and the shrinkage direction of the ink in each pixel grid has a large difference, resulting in poor effect of pixel switching and gray scale control. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a lower substrate which can reduce the opening voltage required for ink rupture, improve the consistency of the ink shrinkage movement direction in each pixel grid, and improve the light characteristics of the display device.

[0006] The present application also provides an electrowetting display device having the above-mentioned lower substrate.

[0007] The present application also provides a manufacturing method for manufacturing the above-mentioned lower substrate.

[0008] According to the lower substrate of the first aspect of the present application, the lower substrate comprises: a lower plate body, a first electrode is arranged on the side surface of the lower plate body; a convex part is arranged on the first electrode, the convex part is tapered along the height direction of the convex part; a hydrophobic insulating layer is arranged on the side of the first electrode close to the convex part and covers the convex part; a pixel wall is arranged on the side of the hydrophobic insulating layer away from the first electrode, the pixel wall defines a plurality of pixel grids, and the convex part is arranged in each pixel grid.

[0009] According to the lower substrate of the present application, at least the following beneficial effects are achieved:

[0010] 1. The present application sets a convex part, so that each pixel grid is arranged with a convex part. Therefore, the thinnest position of the ink in the pixel grid is on the convex part. When a voltage is applied to drive the ink in the pixel grid, the ink on the convex part will break first. The convex part is tapered along the height direction of the convex part, so that the surface transition of the convex part in the height direction is smooth. As the applied voltage increases, the opening rate of the ink shrinkage also increases with the voltage. That is, the ink gradually separates from the surface of the convex part with inclination, avoiding the case that the ink movement direction changes suddenly due to the fault change of the ink separation process on the surface of the cylindrical convex structure. The movement direction of the ink in each pixel grid is controllable by using the convex part, so as to ensure that the movement direction of the ink in each pixel grid is consistent.

[0011] 2. The present application covers the convex part with a hydrophobic insulating layer to separate the convex part and the pixel wall. The convex part and the pixel wall are formed separately. The height and shape of the convex part and the pixel wall are accurate, so that the convex part in each pixel grid accurately induces directional movement of the ink, greatly improving the consistency of the ink movement in each pixel grid.

[0012] 3. Compared with the existing cylindrical convex structure, the present application can reduce the opening voltage, improve the consistency of the ink shrinkage movement direction in each pixel grid, improve the photoelectric performance of the device, increase the electric field response speed, reduce the power consumption, and optimize the stability of the device.

[0013] According to the first aspect of the present application, a lower substrate is provided, wherein the pixel grid has a first symmetry axis and a second symmetry axis, the first symmetry axis and the second symmetry axis are perpendicular to each other, a first area is formed between the inner side wall of the pixel grid, the first symmetry axis and the second symmetry axis, and the convex part is located in the first area.

[0014] According to the first aspect of the present application, a lower substrate is provided, wherein the maximum height of the convex part is 10% to 30% of the height of the pixel wall.

[0015] According to the first aspect of the present application, a lower substrate is provided, wherein the convex part is a circular truncated cone structure, a hemispherical structure or a conical structure.

[0016] According to the first aspect of the present application, a lower substrate is provided, wherein one convex part is arranged in each pixel grid.

[0017] According to the second aspect of the present application, an electrowetting display device is provided, comprising: a lower substrate according to any one of claims 1 to 5; a polar liquid and a non-polar liquid, wherein the polar liquid and the non-polar liquid are filled in the pixel grid; and an upper substrate comprising an upper plate body and a second electrode arranged on the side surface of the upper plate body, wherein the side of the upper plate body close to the second electrode is connected with the pixel wall.

[0018] The electro-wetting display device according to the embodiment of the present application has at least the following beneficial effects:

[0019] 1. The present application sets the convex part, so that each pixel grid is arranged with the convex part. Therefore, the thinnest position of the ink in the pixel grid is on the convex part. When the voltage is applied to drive the ink in the pixel grid, the ink on the convex part is preferentially broken. The convex part is tapered along the height direction of the convex part, so that the surface transition of the convex part in the height direction is smooth. As the applied voltage increases, the opening rate of the ink shrinkage also increases with the increase of the voltage. That is, the ink gradually separates from the surface of the convex part with inclination, avoiding the case that the ink movement direction suddenly changes due to the fault change of the ink separation from the surface of the cylindrical convex structure. The movement direction of the ink in each pixel grid is controlled by the convex part, so that the movement direction of the ink in each pixel grid is controllable, and the movement direction of the ink in each pixel grid is consistent.

[0020] 2. The present application covers the convex part with the hydrophobic insulating layer to separate the convex part and the pixel wall. The convex part and the pixel wall are formed separately. The height and shape of the convex part and the pixel wall are accurate, so that the convex part in each pixel grid accurately induces the directional movement of the ink, and the consistency of the ink movement in each pixel grid is greatly improved.

[0021] 3. Compared with the existing cylindrical convex structure, the present application adopts the tapered convex part, which can reduce the opening voltage, improve the consistency of the ink shrinkage movement direction in each pixel grid, improve the photoelectric performance of the device, improve the electric field response speed, reduce the power consumption, and optimize the stability of the device.

[0022] The manufacturing method of the lower substrate according to the third aspect of the present application is used to manufacture the lower substrate of any one of claims 1 to 5, and comprises the following steps: S1, manufacturing the first electrode on the lower plate body; S2, manufacturing the convex part on the first electrode; S3, manufacturing the hydrophobic insulating layer on the side of the first electrode close to the convex part; and S4, manufacturing the pixel wall on the side of the hydrophobic insulating layer away from the convex part.

[0023] The manufacturing method of the lower substrate according to the embodiment of the present application has at least the following beneficial effects:

[0024] 1. The present application sets a convex part, so that each pixel grid is arranged with a convex part, therefore, the thinnest position of the ink in the pixel grid is on the convex part, when the voltage is applied to drive the ink in the pixel grid, the ink on the convex part breaks preferentially, and the convex part is tapered along the height direction of the convex part, so that the surface transition of the height direction of the convex part is smooth, as the applied voltage increases, the opening rate of the ink shrinkage also increases with the increase of the voltage, the movement direction of the ink in each pixel grid is controllable by using the convex part, which avoids the sudden change of the movement direction of the ink caused by the control of the ink movement by using the cylindrical convex structure, and ensures the consistency of the movement direction of the ink in each pixel grid.

[0025] 2. The present application separates the convex part and the pixel wall, which can be made by using the light pressure printing technology, the convex part with a certain height and shape is first made, then the hydrophobic insulating layer is made, and then the pixel wall is made, so that the convex part and the pixel wall are formed separately and do not affect each other during the manufacturing process, so that the height and shape of the convex part and the pixel wall are accurate, and the movement direction of the ink in each pixel grid is accurately induced by the convex part, which greatly improves the consistency of the movement of the ink in each pixel grid.

[0026] 3. Compared with the existing cylindrical convex structure, the present application can reduce the opening voltage, improve the consistency of the shrinkage movement direction of the ink in each pixel grid, improve the photoelectric performance of the device, improve the response speed of the electric field, reduce the power consumption, and optimize the stability of the device.

[0027] According to the third aspect of the present application, a method for manufacturing a lower substrate, S2 comprises the steps of:

[0028] A first mask plate is prepared, which has a light transmission area matching the shape of the convex part; a layer of first photoresist is spin-coated on the first electrode, which is cured by heating and cooled to room temperature; the first photoresist is exposed using the first mask plate, and then post-baked and cured to form the convex part.

[0029] According to the third aspect of the present application, a method for manufacturing a lower substrate, S3 comprises the steps of: spin-coating a hydrophobic insulating material on the surface of the first electrode and covering the convex part to form a hydrophobic insulating layer.

[0030] According to the third aspect of the present application, a method for manufacturing a lower substrate, S4 comprises the steps of: preparing a second mask plate, which has a light transmission area matching the shape of the pixel wall; spin-coating a layer of second photoresist on the surface of the hydrophobic insulating layer away from the convex part, which is cured by heating and cooled to room temperature; the second photoresist is exposed using the second mask plate, and then post-baked and developed to form the pixel wall.

[0031] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of an electrowetting display device according to an embodiment of the present invention;

[0034] Figure 2 for Figure 1 A top view schematic diagram of a pixel wall structure on a lower substrate is shown;

[0035] Figure 3 for Figure 1 A schematic diagram of a pixel grid structure on a lower substrate is shown.

[0036] Figure 4 for Figure 1 The diagram shows a state structure of an electrically wetted display device where the ink shrinks after a voltage is applied.

[0037] Figure 5 for Figure 1 A schematic diagram of the structure of a protrusion on a lower substrate is shown;

[0038] Figure 6 for Figure 1 A manufacturing process diagram of a lower substrate is shown;

[0039] Figure 7 for Figure 1 The diagram shows a manufacturing process structure of a lower substrate.

[0040] Reference numerals: 100-lower plate, 110-first electrode, 120-protrusion, 130-hydrophobic insulating layer, 140-pixel wall, 150-pixel grid, 160-first axis of symmetry, 170-second axis of symmetry, 180-first region, 190-upper plate, 200-second electrode, 210-first mask, 220-second mask. Detailed Implementation

[0041] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below are exemplary and are intended to explain the present application, but are not to be understood as limiting the present application.

[0042] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc., is based on the orientation or position relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0043] In the description of the present application, the meaning of several is one or more, and the meaning of multiple is two or more. Greater than, less than, more than, etc. are understood as not including the number, and above, below, etc. are understood as including the number. If it is described as first and second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of technical features indicated.

[0044] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting, connecting and connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] An under substrate, an electrowetting display device and a manufacturing method of an under substrate according to an embodiment of the present application are described below with reference to the accompanying drawings.

[0046] The present application aims to provide an embodiment of an under substrate, an electrowetting display device and a manufacturing method of an under substrate.

[0047] In terms of structure, referring to Figure 1 An electrowetting display device mainly includes an under substrate, a polar liquid, a non-polar liquid and an upper substrate.

[0048] It should be noted that the non-polar liquid is usually ink.

[0049] An embodiment of the present invention provides a lower substrate comprising a lower plate 100, a protrusion 120, a hydrophobic insulating layer 130, and a pixel wall 140. A first electrode 110 is disposed on a side surface of the lower plate 100. The protrusion 120 is disposed on the first electrode 110 and gradually tapers along its height direction. The hydrophobic insulating layer 130 is disposed on the side of the first electrode 110 near the protrusion 120 and covers the protrusion 120. The pixel wall 140 is disposed on the side of the hydrophobic insulating layer 130 away from the first electrode 110. (Refer to...) Figure 2 The pixel wall 140 defines multiple pixel grids 150, and a protrusion 120 is arranged in each pixel grid 150.

[0050] Furthermore, polar liquid and non-polar liquid are filled in the pixel grid 150. The upper substrate includes an upper plate 190 and a second electrode 200 disposed on the side surface of the upper plate 190. The side of the upper plate 190 near the second electrode 200 is connected to the pixel wall 140.

[0051] In some embodiments of the present invention, reference is made to... Figure 3 The pixel grid 150 has a first axis of symmetry 160 and a second axis of symmetry 170, which are perpendicular to each other. A first region 180 is formed between the inner wall of the pixel grid 150, the first axis of symmetry 160 and the second axis of symmetry, and the protrusion 120 is located within the first region 180.

[0052] It is understandable that by arranging the protrusion 120 within the first region 180, that is, by arranging the protrusion 120 at the corner of the pixel grid 150, when a voltage is applied to drive the ink to change from a spreading state to a contracting state, the ink at the position of the protrusion 120 breaks. As the voltage increases, the ink contracts and moves from one side of the pixel grid 150 to the other side, which helps to control the ink movement direction within each pixel grid 150 to be consistent.

[0053] In some embodiments of the present invention, a protrusion 120 is provided within each pixel grid 150.

[0054] When applying voltage to drive the ink, it is necessary to ensure that the ink breaks only at one protrusion 120. By gradually increasing the voltage, the ink is directionally contracted and moved, ensuring that the ink movement direction is consistent within each pixel grid 150.

[0055] It should be noted that if there is more than one protrusion 120 in the pixel grid 150, when the voltage is applied to drive the ink, multiple ink cracks will appear in the pixel grid 150. The shrinkage of multiple ink cracks will cause the ink shrinkage and movement to become disordered.

[0056] In some embodiments of the present invention, the protrusion 120 is a frustum-shaped structure, a hemispherical structure, or a conical structure.

[0057] It can be understood that the convex portion 120 has various forms of tapered protrusion, and the convex portion 120 can be made into a circular truncated cone structure, a hemispherical structure or a conical structure.

[0058] Preferably, the convex portion 120 is a circular truncated cone structure, and the circular truncated cone-shaped convex portion 120 has a certain inclination, which can avoid sudden changes in the ink shrinkage movement and more easily control the ink directional shrinkage movement. Figure 5

[0059] In some embodiments of the present application, the maximum height of the convex portion 120 protrusion is 10% to 30% of the height of the pixel wall 140.

[0060] Further, the maximum height of the convex portion 120 protrusion is ≤10um.

[0061] Since the height of the convex portion 120 is limited by the thickness of the ink, it is necessary to ensure that the height of the convex portion 120 is less than the thickness of the ink. If the height of the convex portion 120 is less than 10% of the height of the pixel wall 140, it may make the opening voltage required for ink rupture larger, which is not conducive to controlling power consumption; if the height of the convex portion 120 exceeds 30% of the height of the pixel wall 140, the thickness of the ink must be increased, which may cause the ink to flip over the pixel wall 140 during the ink shrinkage movement when the voltage is applied to drive the ink.

[0062] Therefore, the lower substrate of the present application is provided with the convex portion 120, so that each pixel cell 150 is arranged with the convex portion 120. Therefore, the thinnest position of the ink in the pixel cell 150 is on the convex portion 120, and when the voltage is applied to drive the ink in the pixel cell 150, the ink on the convex portion 120 ruptures first, and the convex portion 120 is tapered along the height direction of the convex portion 120 protrusion, so that the surface of the convex portion 120 in the height direction is smooth, and as the applied voltage increases, the opening rate of the ink rupture shrinkage also increases with the increase of the voltage, that is, the ink gradually separates from the surface of the convex portion 120 with inclination, which avoids the case that the ink movement direction suddenly changes due to the fault change in the surface separation process of the cylindrical protruding structure, and the movement direction of the ink in each pixel cell 150 is controllable by using the convex portion 120, so as to ensure that the movement direction of the ink in each pixel cell 150 is consistent. Figure 4

[0063] ​​In terms of manufacturing, a lower substrate of the present application is manufactured using photopatterning technology, which is not like photolithography that removes material from the substrate, but is based on moving material on the substrate. This technology is able to create complex textures because it uses a latent image, so multiple exposures can be made before development. A unique feature of this process is the non-contact development of the relief structure by heating. Unlike traditional patterning techniques, photopatterning does not require contact with a mold or solvent, but uses heat.

[0064] It can be understood that the application of a patterned UV exposure to a photopolymer to create a latent image can be done through a photomask, during which the monomers begin to polymerize, and due to the low mobility of reactive species in the solid photopolymer layer at room temperature, the polymerization reaction is limited, and a latent image is obtained.

[0065] When the sample is heated, the mobility of the molecules in the photopolymer increases, which enhances the polymerization reaction and the diffusion of active species to the exposed area. Diffusion leads to a local increase in volume in the exposed area, which manifests as a surface relief structure.

[0066] Based on the above technology, referring to Figure 6 and Figure 7 , a method for manufacturing a lower substrate of an embodiment of the present application includes the steps of:

[0067] S1, a first electrode 110 is made on a lower plate body 100.

[0068] S2, a convex part 120 is made on the first electrode 110.

[0069] S3, a hydrophobic insulating layer 130 is made on the first electrode 110 near the convex part 120.

[0070] S4, a pixel wall 140 is made on the hydrophobic insulating layer 130 away from the convex part 120.

[0071] Further, S2 includes the steps of: preparing a first mask 210, which has a light transmission area matching the shape of the convex part 120; spin coating a layer of first photoresist on the first electrode 110, which is cured by warming on a hot plate and cooled to room temperature; using the first mask 210 to expose the first photoresist, and again performing a warming curing process on the hot plate, i.e., a post-baking process, to form the convex part 120.

[0072] It should be noted that the first photoresist is one of SU-8 photoresist, Fujifilm SC-450 photoresist, and HN-022N negative photoresist.

[0073] Further, S3 comprises the steps of: spin coating a hydrophobic insulating material on the surface of the first electrode 110 and covering the protrusions 120 to form a hydrophobic insulating layer 130; after spin coating, performing a warm curing treatment on a hot plate; baking in an oven and cooling to room temperature; after cooling, placing in a reactive ion etching machine for modification, so that the hydrophobic insulating layer 130 changes from a hydrophobic state to a hydrophilic state.

[0074] Further, S4 comprises the steps of: preparing a second mask plate 220, the second mask plate 220 having a light-transmitting area matching the shape of the pixel wall 140; spin coating a second photoresist on the surface of the hydrophobic insulating layer 130 away from the protrusions 120, and performing a warm curing on a hot plate and cooling to room temperature; using the second mask plate 220 to perform an exposure treatment on the second photoresist, and then performing a warm curing treatment on the hot plate again, i.e., a post-baking treatment, and then cooling to room temperature; and finally performing a developing treatment to remove the excess second photoresist material remaining on the hydrophobic insulating layer 130, thereby forming the pixel wall 140, and using the pixel wall 140 to define a plurality of pixel cells 150, so as to ensure that each pixel cell 150 has and only has one protrusion 120.

[0075] It should be noted that the second photoresist is HN-022N photoresist.

[0076] The manufacturing method of the electro-wetting display device according to the embodiment of the present application comprises the steps of:

[0077] Manufacturing a lower substrate.

[0078] Filling treatment, filling the non-polar liquid and the polar liquid into the pixel cells 150.

[0079] Pressing treatment, bonding the upper substrate and the lower substrate together.

[0080] Therefore, by separating the manufacture of the protrusions 120 and the pixel wall 140, the light pressure printing technology can be used to manufacture the protrusions 120 and the pixel wall 140, the protrusions 120 of a certain height and shape are first manufactured, then the hydrophobic insulating layer 130 is manufactured, and then the pixel wall 140 is manufactured, so that the protrusions 120 and the pixel wall 140 are formed separately and do not affect each other in the manufacturing process, the height and shape of the protrusions 120 and the pixel wall 140 are accurate, and the protrusions 120 in each pixel cell 150 accurately induce the directional movement of the ink, thereby greatly improving the consistency of the ink movement in each pixel cell 150.

[0081] The driving mode of the electro-wetting display device according to the embodiment of the present application is as follows:

[0082] When the upper substrate and the lower substrate are energized, the electric field generated will cause the positively charged polar liquid to move towards the negative charge area at the bottom, and the polar liquid will push the non-polar liquid to one side, so that the pixel displays the color at the bottom.

[0083] Specifically, a negative electrode is applied on the first electrode 110, and a positive electrode is applied on the second electrode 200. When the applied voltage is higher than the opening voltage of the non-polar fluid, the non-polar fluid will change its shape from the initial wet state to the shrinkage state, and in this state, the thickness of the ink will also be maintained within the range of the pixel wall 140; when the voltage is lower than the opening voltage of the non-polar fluid, the non-polar fluid will remain in the spreading state.

[0084] Therefore, the shape change of the non-polar fluid can be controlled by adjusting the voltage.

[0085] In the description of the present specification, the description of the terms "one embodiment, some embodiments, illustrative embodiments, examples, specific examples, or some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0086] The embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the present application.

Claims

1. A lower substrate, characterized by, include: The lower plate (100) has a first electrode (110) on its side surface. A protrusion (120) is disposed on the first electrode (110), and the protrusion (120) is gradually reduced along the height direction of its own protrusion; A hydrophobic insulating layer (130) is disposed on the side of the first electrode (110) near the protrusion (120) and covers the protrusion (120). A pixel wall (140) is disposed on the side of the hydrophobic insulating layer (130) away from the first electrode (110). The pixel wall (140) defines a plurality of pixel grids (150), and the protrusion (120) is arranged in each pixel grid (150). The maximum height of the protrusion (120) is 10% to 30% of the height of the pixel wall (140); A protrusion (120) is provided within each pixel grid (150); The thinnest point of ink within the pixel grid (150) is on the protrusion (120).

2. The underlay of claim 1, wherein, The pixel grid (150) has a first axis of symmetry (160) and a second axis of symmetry (170), the first axis of symmetry (160) and the second axis of symmetry (170) are perpendicular to each other, a first region (180) is formed between the inner wall of the pixel grid (150), the first axis of symmetry (160) and the second axis of symmetry (170), and the protrusion (120) is located in the first region (180).

3. The underlay of claim 1, wherein, The protrusion (120) is a frustum-shaped structure, a hemispherical structure, or a conical structure.

4. An electrowetting display device, characterized in that include: A lower substrate as described in any one of claims 1 to 3; Polar liquid and non-polar liquid, the polar liquid and the non-polar liquid filling the pixel grid (150); The upper substrate includes an upper plate body (190) and a second electrode (200) disposed on the side surface of the upper plate body (190). The upper plate body (190) is connected to the pixel wall (140) on the side near the second electrode (200).

5. A method for manufacturing a lower substrate according to any one of claims 1 to 3, characterized by, Including the following steps: S1, the first electrode (110) is fabricated on the lower plate (100). S2, the protrusion (120) is formed on the first electrode (110). S3, a hydrophobic insulating layer (130) is formed on the side of the first electrode (110) near the protrusion (120). S4, a pixel wall (140) is formed on the side of the hydrophobic insulating layer (130) away from the protrusion (120).

6. The method of manufacturing a lower substrate according to claim 5, wherein S2 includes the following steps: Prepare a first mask having a light-transmitting area that matches the shape of the protrusion (120); A first photoresist layer is spin-coated onto the first electrode (110), and the first photoresist is cured by heating and then cooled to room temperature; The first photoresist is exposed using the first mask and then post-baked to form the protrusion (120).

7. The method of claim 5, wherein S3 includes the following steps: A hydrophobic insulating material is spin-coated onto the surface of the first electrode (110) and covers the protrusion (120) to form a hydrophobic insulating layer (130).

8. The method of claim 5, wherein S4 includes the following steps: A second mask plate is prepared, which has a light-transmitting area matching the shape of the pixel wall (140); A second photoresist is spin-coated on the surface of the hydrophobic insulation layer (130) away from the convex part (120), and the second photoresist is solidified by heating and cooled to room temperature; The second photoresist is exposed using the second mask plate, and then post-baking and developing are performed to form the pixel wall (140).

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