Electrophoresis display screen

Abstract

The invention provides an electrophoresis display screen which comprises a first substrate and an electrophoresis layer arranged on the first substrate, and a plurality of charged particles are arranged in the electrophoresis layer; a pixel electrode is arranged on the first substrate, and the pixel electrode is configured to be capable of gathering charged particles on the pixel electrode or diffusing the charged particles into the electrophoresis layer when voltage is applied; the pixel electrode comprises a plurality of pixel units which are arranged repeatedly, the pixel electrode forms a closed first pattern along the boundary of each pixel unit, a second pattern is formed in the first pattern, and the first pattern and the second pattern are connected through a third pattern. By introducing the second pattern into the first pattern at the boundary of the polygonal pixel electrode, the aperture opening ratio of the pixel unit can be improved on the premise of meeting the existing design specification, so that the transmittance of the electrophoretic display screen is improved.

Description

Technical Field

[0001] This invention relates to the field of electronic paper display technology, and more specifically, to an electrophoretic display screen. Background Technology

[0002] Electrophoretic display technology is widely used in e-readers, electronic tags, and smart glass due to its low power consumption, bistable operation, and paper-like display characteristics. This technology controls the movement of charged ink particles in an electrophoretic solution by applying voltage to electrodes. When the driving electrode is energized, ink particles accumulate and deposit on the electrode, exposing light-transmitting areas and achieving the transparent state of the electrophoretic display. Changing the voltage of the driving electrode causes the ink particles to diffuse uniformly between the substrates, switching from a transparent to a light-blocking state.

[0003] In existing electrophoretic display electrode designs, conventional electrode patterns such as checkerboard or hexagonal grids are typically used to achieve uniform particle actuation. However, the electrode structure design is constrained by design rules for actuation and manufacturing. To ensure that ink particles can be fully actuated by the electric field without dead zones, existing design rules require that the distance between two adjacent electrode traces cannot exceed a predetermined value (e.g., the line spacing between electrodes should not exceed 100 μm).

[0004] Within the constraints of this design specification, and considering the achievable limit of electrode linewidth (typically 10μm), the aperture ratio of traditional densely arranged checkerboard or single hexagonal designs has reached its limit. Because a densely arranged grid is necessary to maintain a sufficiently small trace spacing, the opaque electrode lines occupy a large area of ​​the entire panel. Therefore, in current conventional designs, the aperture ratio can typically only reach around 80%, and cannot be further improved. This directly results in low transmittance of electrophoretic dimming glass when it is transparent, making it insufficiently bright when light is transmitted.

[0005] Therefore, there is an urgent need for a new electrode structure design that can improve the aperture ratio of the ink electrode based on existing design specifications, thereby improving the overall transmittance of the electrophoretic display screen and making the transparent state have higher brightness. Summary of the Invention

[0006] To address the aforementioned issues, this application provides an electrophoretic display screen, comprising: a first substrate and an electrophoretic layer disposed thereon, wherein a plurality of charged particles are disposed in the electrophoretic layer;

[0007] A pixel electrode is disposed on the first substrate. The pixel electrode is configured to allow charged particles to gather on it or diffuse into the electrophoretic layer when a voltage is applied.

[0008] The pixel electrode includes multiple pixel units arranged in a repeating pattern. The pixel electrode forms a closed first pattern along the boundary of each pixel unit and forms a second pattern inside the first pattern. The first pattern and the second pattern are connected by a third pattern.

[0009] Optionally, the first pattern is a regular hexagon.

[0010] Optionally, the shape of the second pattern is a regular hexagon or a circle.

[0011] Optionally, the distance between the inner edge of the first pattern and the outer edge of the second pattern in the vertical direction is no greater than 100 μm; and

[0012] The maximum diameter of the inscribed circle of the area enclosed by the second pattern is no greater than 100 μm.

[0013] Optionally, the pixel electrode includes a first electrode layer and a second electrode layer that are disposed in an overlapping manner;

[0014] The first electrode layer is disposed above the second electrode layer and is electrically connected to the second electrode layer through a via.

[0015] Optionally, the first pattern, the second pattern, and the third pattern are simultaneously formed on the first electrode layer and the second electrode layer.

[0016] Optionally, the second and third patterns are formed on the second electrode layer, and the first pattern is formed on both the first and second electrode layers.

[0017] Optionally, the first electrode layer is configured to adsorb charged particles;

[0018] The second electrode layer is configured to drive charged particles to diffuse into the electrophoretic layer.

[0019] Optionally, the pixel electrode includes multiple pixel regions, each pixel region including a central pixel unit and six surrounding pixel units;

[0020] The connection positions of the third pattern and the first pattern of the six pixel units on the first pattern are distributed in a clockwise or counterclockwise direction.

[0021] Optionally, the pixel electrode includes multiple pixel regions, each pixel region including three pixel units that are adjacent to each other in pairs;

[0022] The connection position of the third pattern of each of the three pixel units with the first pattern corresponds to the common intersection point of the first pattern of the three pixel units.

[0023] Based on the technical solutions of the above embodiments, the electrophoretic display screen provided in this application introduces a second pattern inside the first pattern of the polygonal pixel electrode boundary, thereby improving the aperture ratio of the pixel unit under existing design specifications and making the electrophoretic display screen have higher transmittance.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0025] Figure 1 A cross-sectional schematic diagram of an electrophoresis display screen according to an embodiment of this application is shown;

[0026] Figure 2 (a) Figure 2 (b) and Figure 2 (c) A schematic diagram of a pixel electrode within a pixel unit according to an optional embodiment of this application is shown. Figure 2 (d) shows a schematic diagram of a pixel electrode within a pixel unit according to the prior art;

[0027] Figure 3 A partial schematic diagram of a pixel circuit according to one embodiment of this application is shown;

[0028] Figure 4 A partial schematic diagram of a pixel circuit according to one embodiment of this application is shown;

[0029] Figure 5 A schematic diagram of the structure of the first pixel layer and the second pixel layer in a pixel circuit according to an embodiment of this application is shown;

[0030] Figure 6 A schematic diagram of the structure of the first pixel layer and the second pixel layer in a pixel circuit according to one embodiment of this application is shown.

[0031] Figure label:

[0032] 101: First substrate;

[0033] 102: Second substrate;

[0034] 110: Pixel electrode;

[0035] 120: Base;

[0036] 130: Electrophoretic layer;

[0037] 131: Charged particles;

[0038] 210, 310, 410, 510, 610: pixel units;

[0039] 211, 311, 411, 511, 611: First pattern;

[0040] 212, 312, 412, 512, 612: Second pattern;

[0041] 213, 313, 413, 513, 613: Third pattern;

[0042] 300, 400, 500, 600: pixel area;

[0043] 501, 601: First electrode layer;

[0044] 502, 602: Second electrode layer. Detailed Implementation

[0045] The technical solutions of the embodiments of this disclosure will now be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are preferred embodiments of this disclosure and should not be considered as excluding other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0046] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0048] Traditional pixel electrodes are typically arranged in quadrilateral or hexagonal shapes. To ensure that charged particles can be fully driven, the distance between parallel lines of the pixel electrode pattern must not exceed a certain limit, thus restricting the maximum aperture ratio of the pixel unit. Therefore, there is a need to provide an electrophoretic display that improves the maximum aperture ratio of the pixel unit by redesigning the pixel electrode pattern within the pixel unit.

[0049] An embodiment of this application provides an electrophoresis display screen, such as... Figure 1 As shown, the display includes a first substrate 101 and a second substrate 102 disposed opposite to each other, wherein the second substrate 102 is disposed above the first substrate 101, and an electrophoretic layer 130 is disposed between the two. A pixel electrode 110 is disposed on the first substrate 101, and a base electrode 120 is disposed on the second substrate 102. The base electrode 120 and the pixel electrode 110 are insulated from each other. The pixel electrode 110 includes a plurality of closely arranged pixel units, wherein each pixel unit corresponds to a pixel of the electrophoretic display. Since the structure of each pixel is basically the same, in the following figures, the electrophoretic display will be represented by a single pixel unit.

[0050] by Figure 1 The following example illustrates the driving method of the electrophoretic display screen according to an embodiment of this application. It should be noted that the driving method of the electrophoretic display screen is not limited to the following description. When charged particles 131 are uniformly distributed in the electrophoretic layer 130, the pixel unit displays the color of the charged particles 131. A voltage is applied to the pixel electrode 110, generating an electric field between the pixel electrode 110 and the base 120. This causes the charged particles 131 to be driven by the electric field, moving towards the pixel electrode 110 in the electrophoretic layer 130, ultimately as shown... Figure 1 As shown, the charged particles 901 are concentrated on the pixel electrode 110, at which point the pixel unit is in a transparent state. In the transparent state, a voltage is applied to the pixel electrode 110, causing the electric field between the pixel electrode 110 and the base electrode 120 to disappear or generate an opposite electric field. At this point, the charged particles 901 diffuse back into the electrophoretic layer 130 and are uniformly distributed within it. Therefore, the movement of the charged particles 901 can be driven by applying a voltage to the pixel electrode 110, thereby achieving the switching between transparent and colored states for the pixel unit. In the various optional embodiments of this application, the color and electrical properties of the charged particles 901 are not limited.

[0051] In this embodiment, the electrophoretic layer 130 includes an optically transparent dispersion medium and charged particles 131 suspended in the dispersion medium. In an optional embodiment, the dispersion medium includes one or more of isoparaffin solvents, halogenated hydrocarbon solvents, dodecane, or silicone oil. The charged particles 131 are uniformly dispersed in the dispersion medium when no voltage is applied or when a repulsive voltage is applied, thereby blocking light. In an optional embodiment, the charged particles 131 include carbon black particles, titanium dioxide particles, or organic pigment particles. In an optional embodiment, the electrophoretic layer 130 further includes a charge control agent and a surfactant to maintain the charge stability of the charged particles 131 and prevent their aggregation.

[0052] In each pixel unit, pixel electrodes form a closed first pattern along the boundary of the pixel unit. The pixel units are closely arranged to form a whole, thereby covering the surface of the display screen. The pixel units can be arranged in, for example, quadrilateral or hexagonal shapes. A second pattern is formed in the closed first pattern of each pixel unit, and the first and second patterns are connected by a third pattern.

[0053] In an optional embodiment, such as Figure 2 As shown, the pixel unit 210 is a regular hexagon, and the pixel electrode is a strip structure, thus forming a first hexagonal pattern 211 around the periphery of the pixel unit 210. The second pattern 212 is concentrically arranged with the first pattern 211 and connected to the first pattern 211 through a third pattern 213, so that the entire pixel electrode is at the same potential. The second pattern 212 and the third pattern 213 constitute an "island + bridge" structure, providing an additional charged particle adsorption anchor point at the center of the first pattern 211 without affecting the linewidth of the outer first pattern 211. Due to the existence of this structure, the size of the outer first pattern 211 can be appropriately enlarged. The pattern design method according to the embodiment of this application disperses the originally dense pixel electrode traces, forming an "outer ring structure + inner island structure" shape, making the distribution of pixel electrodes in the same area sparser, thereby improving the aperture ratio of the pixel unit. Figure 2 As shown in (a), (b) and (c), the second pattern 212 can be, for example, a regular hexagon or a circle.

[0054] Figure 2 (d) illustrates a prior art arrangement of pixel electrodes, where each pixel unit is arranged in a regular hexagonal pattern. The following section uses... Figure 2 Examples (a) and (d) illustrate the differences in transmittance between embodiments of this application and existing methods under the same design rule.

[0055] In existing technologies, such as Figure 2 As shown in (d), to ensure that charged particles can be fully driven in the electrophoretic layer, the design specification is usually that the distance 'a' between two parallel lines of the pixel electrode pattern is no greater than 100 μm. When the distance is greater than 100 μm, the electric field force may not be sufficient to effectively and completely adsorb the electrophoretic particles onto the target electrode, resulting in too many particles still scattered in the electrophoretic layer blocking light, leading to a decrease in maximum transmittance and uniformity. Furthermore, under the premise that the distance 'a' is no greater than 100 μm, the width of the elongated electrode, i.e., the line width 'b' of the pattern, is, for example, 10 μm, at which point the maximum aperture ratio of the pixel unit is approximately 80%.

[0056] In the embodiments of this application, such as Figure 2As shown in (a), the first pattern 211 is a regular hexagon, and the second pattern 212 is a circle. Similarly, the design specification is that the distance 'a' between two parallel lines is no greater than 100 μm, meaning the vertical distance between the inner edge of the first pattern and the outer edge of the second pattern is no greater than 100 μm, and the maximum inscribed circle diameter of the area enclosed by the second pattern is no greater than 100 μm. The electrode widths, i.e., the line widths of the first pattern 211, the second pattern 212, and the third pattern 213, are also designed to be 10 μm. At this point, the maximum aperture ratio of the pixel unit 210 can reach 91%. Compared to the pattern structure of traditional pixel electrodes, this results in an approximately 10% increase in transmittance.

[0057] In the embodiments of this application, using Figure 2 Taking (a), (b), and (c) as examples, the first pattern 211 and the second pattern 212 are connected by a linear third pattern 213. When multiple pixel units 210 are closely arranged, if the multiple third patterns 213 are positioned in a single direction (e.g., all horizontally to the right), it may cause the electrophoretic display to exhibit diffraction stripes in a single direction visually. Therefore, it is necessary to adjust the positional relationship between the multiple third patterns 213 to avoid the generation of stripes on the display screen.

[0058] In an optional embodiment, such as Figure 3 As shown in (a), a pixel region 300 is formed by seven pixel units 310, each comprising a first pattern 311 in the shape of a regular hexagon, serving as the smallest unit constituting a pixel electrode. This includes a central pixel unit and six surrounding pixel units. In each of the six surrounding pixel units, a third pattern 313 in each pixel unit 310 is connected to one side of the first pattern 311. To avoid stripes on the display screen and to achieve a more uniform distribution of optical effects such as color and brightness, thereby improving the macroscopic visual distribution effect after charged particle aggregation, the connection positions in different pixel units 310 are distributed clockwise or counterclockwise. Specifically, the third patterns 313 of the six peripheral pixel units 310 are rotated and staggered sequentially in a clockwise (or counterclockwise) direction. Figure 3(a) For example, in a pixel area 300, the third pattern 313 in the pixel unit 310 located at the upper right position connects to the lower right, the third pattern 313 in the pixel unit 310 located at the lower right position connects to the lower down, the third pattern 313 in the pixel unit 310 located at the lower position connects to the lower left, the third pattern 313 in the pixel unit 310 located at the lower left position connects to the upper left, the third pattern 313 in the pixel unit 310 located at the upper left position connects to the upper up, and the third pattern 313 in the pixel unit 310 located at the upper position connects to the upper right, thus making the third patterns 313 in each pixel unit 310 distributed in a pinwheel shape. Further, as... Figure 3 As shown in (b), multiple pixel areas 300 arranged as described above are connected to form a pixel electrode. By designing the third pattern 313 in a rotating arrangement, the stripe effect can be effectively eliminated, making the visual distribution of charged particles more uniform.

[0059] In another alternative embodiment, such as Figure 4 As shown in (a), a pixel region 400 is formed by three pixel units 410, each comprising a first pattern 411 in the shape of a regular hexagon, serving as the smallest unit constituting a pixel electrode. Each of the three pixel units 410 is adjacent to the other two. A third pattern 413 in each pixel unit 410 is connected to a corner of the first pattern 411. To avoid stripes on the display screen and to achieve a more uniform overall distribution, the connection positions in different pixel units 410 correspond to the common intersection point of the three first patterns 411. Specifically, within the pixel region 400, the third patterns 413 of the three pixel units 410 extend from the center of the hexagon in the first pattern 411 to the vertex where the three hexagons intersect, forming a "Y" shape. Further, as... Figure 4 As shown in (b), multiple pixel areas 400 are connected to form a pixel electrode. By setting the connection between the third pattern 413 and the first pattern 411 in the already intersecting node area, it is also helpful to avoid the generation of stripe effects.

[0060] In embodiments of this application, a pixel electrode may include two overlapping circuit layers, with a first electrode layer disposed above a second electrode layer and an insulating layer between them. The insulating layer includes vias, through which the first and second electrode layers are electrically connected. In a pixel unit, the first and second electrode layers can jointly form a first pattern, a second pattern, and a third pattern. Optionally, the pattern formed on the first electrode layer can be complementary to the pattern formed on the second electrode layer, and the pattern formed on the first electrode layer can also be partially or entirely identical to the pattern formed on the second electrode layer.

[0061] In embodiments of this application, the insulating layer disposed between the first electrode layer and the second electrode layer is made of a transparent material. In an optional embodiment, the insulating layer comprises an inorganic transparent insulating material, such as one or more of silicon dioxide, silicon nitride, silicon oxynitride, and aluminum oxide. In another optional embodiment, the insulating layer comprises an organic polymer transparent insulating material, such as acrylic resin, transparent polyimide, polysiloxane resin, epoxy resin, etc.

[0062] In an optional embodiment, such as Figure 5 As shown in (a) and (b), the pixel unit 510 has a regular hexagonal structure, and each pixel unit 510 includes a first electrode layer 501 and a second electrode layer 502 with the same structure. The first electrode layer 501 and the second electrode layer 502 respectively include a first pattern 511, a second pattern 512, and a third pattern 513. The first electrode layer 501 is disposed above the second electrode layer 502, and the projections of their patterns in the vertical direction completely overlap.

[0063] By forming identical patterns on the first electrode layer 501 and the second electrode layer 502 and connecting them through vias, the resistance of the entire pixel electrode can be reduced. When applied to large-size displays, this allows for more consistent driving voltages for pixel units at different locations on the screen, thereby improving display uniformity. Simultaneously, the reduced resistance of the pixel electrode enables faster driving speeds of charged particles, which helps to reduce screen response time and increase refresh rate.

[0064] Further optional, such as Figure 5 As shown in (c), three pixel units 510 constitute a pixel region 500, serving as the smallest unit constituting a pixel electrode. Each pixel unit 510 is adjacent to the other two. The connection positions of the first pattern 511 and the third pattern 513 in each pixel unit 510 correspond to the common intersection point of the three hexagons of the first pattern 511. The third pattern 513 extends from the center of the hexagon of the first pattern 511 to the vertex of the common intersection of the three hexagons, forming a "Y" shape. This helps to avoid the generation of stripes on the display screen and makes the overall optical effect distribution more uniform.

[0065] In another alternative embodiment, such as Figure 6 As shown in (a) and (b), the pixel unit 610 has a regular hexagonal structure, and each pixel unit 610 includes a first electrode layer 601 and a second electrode layer 602. Only a first pattern 611 is formed on the first electrode layer 601, while the second electrode layer simultaneously forms the first pattern 611, the second pattern 612, and the third pattern 613. The first electrode layer 601 is disposed above the second electrode layer 602. Figure 6As shown in (c), multiple pixel units 610 form pixel electrodes, thereby creating a two-layer structure for the pixel units, including an upper layer composed of multiple first electrode layers 601 and a lower layer composed of multiple second electrode layers 602. When the electrophoretic display screen becomes transparent, a voltage is applied to the first electrode layer 601, causing charged particles to gather towards the first pattern 611 within the first electrode layer 601, making the pixel unit 610 transparent. Optionally, an auxiliary bias voltage is applied to the second electrode layer 602 at this time, and its electric field penetrates the insulating layer, accelerating the gathering of charged particles towards the first electrode layer 601. When the electrophoretic display screen becomes colored, a repulsive voltage is applied to the second electrode layer 602, thereby driving the charged particles on the first electrode layer 601 to diffuse into the electrophoretic layer, making the pixel unit 610 colored. Accelerating the diffusion of charged particles into the electrophoretic layer through the second electrode layer 602 helps to reduce the response time of the electrophoretic display screen.

[0066] In an optional embodiment, the second electrode layer 602 is made of a transparent material that allows high transmittance of visible light, such as a transparent conductive oxide, a non-oxide thin film, or nanomaterials. Preferably, the second electrode layer 602 is an indium tin oxide (ITO) electrode.

[0067] Further optional, such as Figure 6 As shown in (d), three pixel units 610 constitute a pixel region 600, serving as the smallest unit constituting a pixel electrode. Each pixel unit 610 is adjacent to the other two. The connection positions of the first pattern 611 and the third pattern 613 in each pixel unit 610 correspond to the common intersection point of the three hexagons of the first pattern 611. The third pattern 613 extends from the center of the hexagon of the first pattern 611 to the vertex of the common intersection of the three hexagons, forming a "Y" shape. This helps to avoid the generation of stripes on the display screen and makes the overall optical effect distribution more uniform.

[0068] In the embodiments of this application, by introducing patterns inside the polygonal pixel electrodes, and in conjunction with a specific array connection method or a dual-layer electrode driving architecture, the limit of aperture ratio can be broken while meeting the design specifications of existing driving rules, thereby providing an electrophoretic display screen with higher transmittance.

[0069] The above description is merely a specific embodiment of this application, but the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this invention should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. An electrophoretic display screen, characterized in that, include: A first substrate and an electrophoretic layer disposed thereon, wherein a plurality of charged particles are disposed in the electrophoretic layer; A pixel electrode is disposed on the first substrate, and the pixel electrode is configured to cause charged particles to gather thereon or diffuse into the electrophoretic layer when a voltage is applied. The pixel electrode includes a plurality of pixel units arranged in a repeating pattern. The pixel electrode forms a closed first pattern along the boundary of each pixel unit and forms a second pattern inside the first pattern. The first pattern and the second pattern are connected by a third pattern.

2. The electrophoretic display screen according to claim 1, characterized in that, The first pattern is a regular hexagon.

3. The electrophoretic display screen according to claim 1 or 2, characterized in that, The second pattern is either a regular hexagon or a circle.

4. The electrophoretic display screen according to claim 1 or 2, characterized in that, The distance between the inner edge of the first pattern and the outer edge of the second pattern in the vertical direction is no greater than 100 μm; and The maximum diameter of the inscribed circle of the area enclosed by the second pattern is no greater than 100 μm.

5. The electrophoretic display screen according to claim 1 or 2, characterized in that, The pixel electrode includes an overlapping first electrode layer and a second electrode layer; The first electrode layer is disposed above the second electrode layer and is electrically connected to the second electrode layer through a via.

6. The electrophoretic display screen according to claim 5, characterized in that, The first pattern, the second pattern, and the third pattern are formed simultaneously on the first electrode layer and the second electrode layer.

7. The electrophoretic display screen according to claim 5, characterized in that, The second pattern and the third pattern are formed on the second electrode layer, and the first pattern is formed on both the first electrode layer and the second electrode layer.

8. The electrophoretic display screen according to claim 7, characterized in that, The first electrode layer is configured to adsorb the charged particles; The second electrode layer is configured to drive the charged particles to diffuse into the electrophoretic layer.

9. The electrophoretic display screen according to claim 2, characterized in that, The pixel electrode includes multiple pixel regions, each pixel region including a central pixel unit and six surrounding pixel units; The connection positions of the third pattern and the first pattern of the six pixel units on the first pattern are distributed clockwise or counterclockwise.

10. The electrophoretic display screen according to claim 2, characterized in that, The pixel electrode includes multiple pixel regions, and each pixel region includes three pixel units that are connected in pairs. The connection position of the third pattern of each of the three pixel units with the first pattern corresponds to the common intersection point of the first pattern of the three pixel units.

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