CN219266755U

CN219266755U - Electrophoretic display screen and display device

Info

Publication number: CN219266755U
Application number: CN202223370949.XU
Authority: CN
Inventors: 杨明阳; 田正; 蔡佩芝; 李鑫; 贺海明
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2022-12-14
Filing date: 2022-12-14
Publication date: 2023-06-27
Anticipated expiration: 2032-12-14

Abstract

The embodiment of the application relates to the technical field of display and provides an electrophoretic display screen and a display device. The electrophoretic display screen comprises a first substrate and a second substrate which are oppositely arranged, and an electrophoretic layer positioned between the first substrate and the second substrate. The first substrate includes pixel electrodes and first common electrodes arranged at intervals in a direction perpendicular to a thickness direction of the electrophoretic display screen. The second substrate includes a second common electrode layer. The pixel electrode and the first common electrode are configured to form an electric field intersecting the thickness direction of the electrophoretic display screen, and the second common electrode layer is configured to form an electric field along the thickness direction of the electrophoretic display screen in cooperation with the pixel electrode and the first common electrode. The second common electrode layer comprises an opening, and a projection of the opening on the first substrate at least partially covers a space between the pixel electrode and the first common electrode along a thickness direction of the electrophoretic display screen. The arrangement of the openings improves the light transmittance of the pixels of the electrophoretic display screen in a transparent state.

Description

Electrophoretic display screen and display device

Technical Field

The application relates to the technical field of display, in particular to an electrophoresis display screen and a display device.

Background

In conventional in-plane driven electrophoretic displays, an electrophoretic layer, pixel electrodes and a first common electrode on the same side of the electrophoretic layer, and a second common electrode layer on the other side of the electrophoretic layer are typically included. Wherein the pixel electrode and the first common electrode are used for forming a transverse electric field for driving the charged particles with colors in the electrophoretic layer to move in a direction perpendicular to the thickness direction of the electrophoretic display screen, so that each pixel is switched between a transparent state and a non-transparent state. The second common electrode layer is used for being matched with the pixel electrode and the first common electrode to form a longitudinal electric field for driving the charged particles with colors to move in the thickness direction of the electrophoretic display screen. When charged particles are accumulated on the pixel electrode and/or the first common electrode, the pixel realizes a transparent state; the pixel achieves a non-transparent state when the charged particles are tiled between the pixel electrode and the first common electrode. However, in the conventional in-plane driven electrophoretic display, the transmittance of the pixels in the transparent state is to be improved.

Disclosure of Invention

A first aspect of the present application provides an electrophoretic display. The electrophoretic display screen includes:

the first substrate comprises a pixel electrode and a first public electrode, and the pixel electrode and the first public electrode are arranged at intervals along the direction perpendicular to the thickness direction of the electrophoretic display screen;

A second substrate disposed opposite to the first substrate, the second substrate including a second common electrode layer; and

an electrophoretic layer between the first substrate and the second substrate, the electrophoretic layer including charged particles, the pixel electrode and the first common electrode being configured to form an electric field intersecting the thickness direction of the electrophoretic display screen within the electrophoretic layer, the second common electrode layer being disposed to cooperate with the pixel electrode and the first common electrode to form an electric field along the thickness direction of the electrophoretic display screen within the electrophoretic layer;

the second common electrode layer comprises an opening, and the projection of the opening on the first substrate at least partially covers the interval between the pixel electrode and the first common electrode along the thickness direction of the electrophoretic display screen.

In the electrophoresis display screen of the embodiment of the application, the second common electrode layer comprises an opening, and along the thickness direction of the electrophoresis display screen, the projection of the opening on the first substrate at least partially covers the pixel electrode and the interval between the first common electrodes, when the pixel is in a transparent optical state, charged particles are accumulated on the pixel electrode and/or the first common electrode, and along the thickness direction of the electrophoresis display screen, light corresponding to the interval between the pixel electrode and the first common electrode can penetrate through the opening of the second common electrode layer. Compared with the situation that the second common electrode layer is arranged on the whole surface, the electrophoretic display screen of the embodiment of the application improves the light transmittance of the pixels in the transparent state.

In some embodiments, the second common electrode layer is a patterned layer, and the pattern of the second common electrode layer is a non-periodic pattern. Therefore, the problem of moire can be further improved on the basis of improving the light transmittance of the pixel in the transparent state.

In some embodiments, the second common electrode layer includes a plurality of the openings distributed randomly, and a pattern of each of the openings is a random pattern. That is, the outline of the second common electrode layer defining the shape of the opening is random, and the pattern of the opening may be regular or irregular.

In some embodiments, the pattern of the second common electrode layer includes one or a combination of several of a random dot pattern, a linear pattern, and a planar pattern. The dot pattern does not limit the pattern to be circular, but means that the two-dimensional size of the pattern is small. The dot pattern may be regular round, rectangular, etc., or randomly generated. The line pattern is not limited to a straight line segment, but means that the pattern varies greatly in the ratio of width to length. The linear pattern may be a regular linear segment, an arc segment, or the like, or may be a randomly generated linear pattern. The planar pattern refers to a pattern with a larger two-dimensional size, and the pattern can be in a regular shape or a randomly generated shape.

In some embodiments, the second common electrode layer is a patterned layer, and the pattern of the second common electrode layer is a periodic pattern.

In some embodiments, the second common electrode layer includes a plurality of the openings arranged at intervals.

In some embodiments, a plurality of the openings are arranged in an array.

In some embodiments, the electrophoretic display screen includes a plurality of pixels, and the second common electrode layer corresponds to all the plurality of pixels, where, corresponding to different pixels, the difference of the transmittance of the second common electrode layer to visible light is not greater than 1%, so as to ensure uniformity of display effects of the pixels in a transparent state.

In some embodiments, the charged particles comprise charged particles of a single color of a single polarity. In other embodiments, the charged particles comprise charged particles of multiple colors of a single polarity. In still other embodiments, the charged particles comprise charged particles of multiple colors of multiple polarities.

In some embodiments, the electrophoretic display screen includes a plurality of pixels, each of the pixels corresponding to at least one of the pixel electrodes and one of the first common electrodes.

In some embodiments, the electrophoresis layer further includes a plurality of micro-cup structures, and an inner space of each micro-cup structure is formed as a containing cavity, the charged particles are located in the containing cavity, and each containing cavity corresponds to at least one pixel.

In some embodiments, the electrophoretic display screen further comprises a display layer located on a side of the pixel electrode remote from the electrophoretic layer. The display layer is, for example, a liquid crystal display panel or an organic light emitting diode display panel. Thus, the electrophoretic display screen has the effects of saving electricity and protecting eyes in the electrophoretic display technology and has good color display effect of the liquid crystal display panel or the organic light emitting diode display panel in the transparent state.

In some embodiments, in the case of an electrophoretic particle in which the charged particles are white, the non-transparent state of each of the pixels is a white state, and the transparent state of each of the pixels includes a black state and a display state.

In other embodiments, where the charged particles are black electrophoretic particles, the non-transparent state of each of the pixels is a black state, and the transparent state of each of the pixels includes a white state and a display state.

In still other embodiments, where the charged particles comprise charged electrophoretic particles of opposite polarity, black, and white, the non-transparent state of each of the pixels comprises a black state and a white state, and the transparent state of each of the pixels is a display state.

In some embodiments, each of the pixel electrodes and each of the first common electrodes are elongated extending in the same direction, and one of the first common electrodes is located between two adjacent pixel electrodes.

In some embodiments, each of the pixel electrodes includes a plurality of first branches, each of the first common electrodes includes at least one second branch having the same extension direction as the first branches, and each of the pixel electrodes and a corresponding one of the first common electrodes are arranged such that one of the first branches and one of the second branches are alternately arranged.

A second aspect of the present application provides a display device. The display device comprises an electrophoretic display screen according to the first aspect, which has at least the same advantages as the electrophoretic display screen according to the first aspect, and will not be described in detail here.

Drawings

Fig. 1A is a partial cross-sectional view of a conventional in-plane driven electrophoretic display.

Fig. 1B is a partial cross-sectional view of another conventional in-plane driven electrophoretic display.

Fig. 2 is a partial cross-sectional view of an electrophoretic display screen according to an embodiment of the present application.

Fig. 3 is a schematic layout diagram of a second common electrode layer on a second substrate according to an embodiment of the present application.

Fig. 4 is a partial cross-sectional view of an electrophoretic display screen to which the second common electrode layer of fig. 3 is applied.

Fig. 5 is a schematic layout diagram of a second common electrode layer on a second substrate according to another embodiment of the present application.

Fig. 6 is a schematic layout diagram of a second common electrode layer on a second substrate according to another embodiment of the present application.

Fig. 7 is a schematic layout diagram of a second common electrode layer on a second substrate according to another embodiment of the present application.

Fig. 8A is a schematic layout diagram of a pixel electrode and a first common electrode in an embodiment of the present application.

Fig. 8B is a schematic layout diagram of a pixel electrode and a first common electrode according to another embodiment of the present application.

Fig. 8C is a schematic layout diagram of a pixel electrode and a first common electrode according to another embodiment of the present application.

Description of main reference numerals:

electrophoretic display screens 100, 1, 2

First substrate 10

First substrate 11, 11'

First driving layer 12

Pixel electrodes

13, 13a, 13b, 13c, and PE

First branch 131

First connecting portion 132

First

common electrodes

14, 14a, 14b, 14c, and VBD

Black matrix BM

Second branch 141

Interval G

Second substrate 20

Second substrate 21, 21'

Second common electrode layers 22, 22a, 22b, 22c, 22d, VCOM

Opening H

Second common electrode 221

Electrode stripe 223

Electrophoretic layer 30, 30'

Microcup structure 31

Accommodation chamber 31a

Electrophoretic medium 32

Charged particles 33, a

Pixel P

Display layer 40

Third substrate 41

Display driving layer 42

Light emitting element layer 43

Polarizing layer 44

Light L, L', L1, L2, L3

Display state (I)

White state (II)

Black state (III)

First direction D1

Second direction D2

Detailed Description

Fig. 1A is a partial cross-sectional view of a conventional in-plane driven electrophoretic display. As shown in fig. 1A, in the electrophoretic display panel 1, a first substrate 11' and a second substrate 21' are disposed opposite to each other, and an electrophoretic layer 30' is disposed between the first substrate 11' and the second substrate 21 '. The pixel electrode PE and the first common electrode VBD are spaced apart from each other in a thickness direction perpendicular to the electrophoretic display panel 1 on a side of the first substrate 11 'close to the second substrate 21'. The second common electrode layer VCOM is disposed at a side of the second substrate 21 'close to the first substrate 11'. The electrophoretic layer 30' comprises charged particles a having a color. Specifically, the pixel electrode PE and the first common electrode VBD are used to form a transverse electric field perpendicular to the thickness direction of the electrophoretic display panel 1 to drive the charged particles a to move transversely in the thickness direction perpendicular to the electrophoretic display panel 1. The second common electrode layer VCOM is used to form a longitudinal electric field in the thickness direction of the electrophoretic display screen 1 in cooperation with the pixel electrode PE and the first common electrode VBD, so as to drive the charged particles a to move longitudinally in the thickness direction of the electrophoretic display screen 1. When charged particles a are accumulated on the pixel electrode PE and/or the first public electrode VBD, the corresponding pixels realize transparent states; when the charged particles a are tiled between the pixel electrodes PE and/or the first common electrode VBD, a corresponding realization of a non-transparent state is achieved.

However, in the conventional electrophoretic display 1, the second common electrode layer VCOM is disposed on the second substrate 21' over the whole surface, the second common electrode layer VCOM is a continuous whole layer without any patterning treatment, and there is a difference in refractive index between the electrophoretic fluids in the second substrate 21', the second common electrode layer VCOM, and the electrophoretic layer 30 '. Typically, the material of the second substrate 21 'is glass, the refractive index of which is about 1.5, the material of the second common electrode layer VCOM is indium tin oxide, the refractive index of which is about 2, and the refractive index of the electrophoretic fluid in the electrophoretic layer 30' is about 1.4. Therefore, when the charged particles a are stacked on the pixel electrode PE, the pixel where the pixel electrode PE is in a transparent optical state, since the second common electrode layer VCOM is disposed on the whole surface and the refractive index layer difference between the second substrate 21', the second common electrode layer VCOM and the electrophoretic liquid in the electrophoretic layer 30', the light L from the first substrate 11' side of the electrophoretic display screen 1 is at least partially reflected to the area far from the second substrate 21' at the second common electrode layer VCOM, and cannot exit from the second substrate 21', so that the light transmittance of the pixel in the electrophoretic display screen 1 in the transparent optical state is greatly lost, and the display effect of the electrophoretic display screen 1 is affected.

In addition, in the electrophoretic display 1 shown in fig. 1A, in the transparent state, the charged particles a stacked on the pixel electrode PE and/or the first common electrode VBD can reflect the light from the second substrate 21' side to display the color of the charged particles a, thereby affecting the display effect of the pixels of the electrophoretic display 1 in the transparent state.

Fig. 1B is a partial cross-sectional view of another conventional in-plane driven electrophoretic display. The difference between the electrophoretic display panel 2 of fig. 1B and the electrophoretic display panel 1 of fig. 1A is that: the electrophoretic display screen 2 further comprises a black matrix BM. As shown in fig. 1B, the black matrix BM is disposed on a side of the second common electrode layer VCOM close to the electrophoretic layer 30' and is disposed corresponding to one pixel electrode PE. The projection of the black matrix BM on the first substrate 11 'covers the projection of the pixel electrode PE on the first substrate 11' to block the light L 'from the side (or display side) of the second substrate 21' in the transparent state, so as to avoid the light L 'entering the electrophoretic layer 30' and being reflected by the charged particles a deposited on the pixel electrode PE to display the color of the charged particles a, so that the display effect of the pixels of the electrophoretic display screen 2 in the transparent state is better.

It is understood that the black matrix BM may be disposed corresponding to the electrode where charged particles a need to be stacked in the transparent state and is not limited to be disposed corresponding to only the pixel electrode PE. For example, in some embodiments, in which the pixel is in a transparent optical state, the charged particles a are deposited on the first common electrode VBD, and then the black matrix BM is disposed corresponding to the first common electrode VBD. Still alternatively, in other embodiments, in which the pixel is in a transparent optical state and the charged particles a are deposited on the pixel electrode PE and the first common electrode VBD, the black matrix BM is disposed corresponding to the pixel electrode PE and the first common electrode VBD, respectively.

However, since the black matrix BM has a certain thickness (e.g. 1 μm to 5 μm), when the black matrix BM is aligned with the pixel electrode PE and/or the first common electrode VBD below, there is a misalignment, so that the black matrix BM cannot be exactly aligned with the corresponding electrode. Moreover, since the black matrices BM are also generally periodically arranged, the arrangement of the black matrices BM further aggravates the phenomenon of moire.

To this end, embodiments of the present application provide an electrophoretic display screen and a display device. The electrophoretic display screen comprises a first substrate, a second substrate and an electrophoretic layer, wherein the first substrate and the second substrate are oppositely arranged, and the electrophoretic layer is positioned between the first substrate and the second substrate. The first substrate includes a pixel electrode and a first common electrode. The pixel electrode and the first common electrode are arranged at intervals along the direction perpendicular to the thickness direction of the electrophoretic display screen. The second substrate includes a second common electrode layer. The pixel electrode and the first common electrode are configured to form an electric field intersecting the thickness direction of the electrophoretic display screen within the electrophoretic layer, and the second common electrode layer is disposed to cooperate with the pixel electrode and the first common electrode to form an electric field along the thickness direction of the electrophoretic display screen within the electrophoretic layer. The second common electrode layer comprises an opening, and the projection of the opening on the first substrate at least partially covers the interval between the pixel electrode and the first common electrode along the thickness direction of the electrophoretic display screen.

In the electrophoresis display screen of the embodiment of the present application, the second common electrode layer is a whole layer discontinuously disposed, and includes an opening penetrating through two opposite surfaces of the whole layer, and along a thickness direction of the electrophoresis display screen, a projection of the opening on the first substrate at least partially covers the pixel electrode and an interval between the first common electrodes. When the pixel is in the transparent optical state, charged particles are accumulated on the pixel electrode and/or the first common electrode, and light at a space between the corresponding pixel electrode and the first common electrode can pass through the opening of the second common electrode layer along the thickness direction of the electrophoretic display screen. Compared with the situation that the second common electrode layer is arranged on the whole surface, the electrophoretic display screen of the embodiment of the application improves the light transmittance of the pixels in the transparent state. In some embodiments, the pattern of the second common electrode layer is an aperiodic pattern, which can further improve the problem of moire on the basis of improving the transmittance of the pixel in the transparent state.

The following description of the technical solutions in the embodiments of the present application will be made clearly and completely with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments.

Fig. 2 is a partial cross-sectional view of an electrophoretic display screen according to an embodiment of the present application. As shown in fig. 2, the electrophoretic display panel 100 includes a first substrate 10, a second substrate 20 disposed opposite to the first substrate 10, an electrophoretic layer 30 between the first substrate 10 and the second substrate 20, and a display layer 40.

The first substrate 10 includes a first base 11, a first driving layer 12, a pixel electrode 13, and a first common electrode 14. The first substrate 11 is transparent, and is made of glass, for example. The first driving layer 12 is positioned at a side of the first substrate 11 near the electrophoretic layer 30 for applying a driving signal to the pixel electrode 13. The pixel electrode 13 and the first common electrode 14 are positioned at the same side of the electrophoretic layer 30 and are spaced apart in a thickness direction perpendicular to the electrophoretic display panel 100. The electrophoretic display screen 100 comprises a plurality of pixels P (three pixels P are schematically shown in fig. 2). The size of each pixel P is about 96 micrometers, but is not limited thereto. Each pixel P includes a pixel electrode 13 and a corresponding first common electrode 14. The first common electrode 14 is located between two adjacent pixel electrodes 13. In other embodiments, each pixel P may correspond to two or more pixel electrodes 13.

The pixel electrode 13 and the first common electrode 14 are arranged to cooperate to form an electric field (also referred to as an electric field in a horizontal direction, or a horizontal electric field, or a lateral electric field) within the electrophoretic layer 30 intersecting the thickness direction of the electrophoretic display screen 100. The first driving layer 12 includes, for example, a plurality of thin film transistors (not shown), a plurality of data lines (not shown), and a plurality of scan lines (not shown). Each pixel electrode 13 is electrically connected to a corresponding thin film transistor, a corresponding data line and a corresponding scan line. The materials of the pixel electrode 13 and the first common electrode 14 are transparent conductive materials such as indium tin oxide, indium zinc oxide, and the like.

The electrophoretic layer 30 includes a plurality of micro-cup structures 31, and an inner space of each micro-cup structure 31 is formed as one receiving cavity 31a. The plurality of accommodating chambers 31a are independent from each other. In the embodiment shown in fig. 2, each of the accommodating chambers 31a corresponds to one pixel P. In other embodiments, each receiving cavity 31a may correspond to two or more pixels P, i.e., each receiving cavity 31a corresponds to two or more pixel electrodes 13. Electrophoretic layer 30 further comprises an electrophoretic medium 32 positioned within receiving chamber 31a and charged particles 33 positioned in electrophoretic medium 32. The micro-cup structure 31 is transparent. The material of the micro-cup structure 31 is, for example, photoresist, but not limited thereto. Electrophoretic medium 32 is transparent. The electrophoresis medium 32 may be, for example, isoparaffin solvent oil (e.g., isopar G), dodecane, tetrachloroethylene, etc., but is not limited thereto. The charged particles 33 are negatively charged white electrophoretic particles. The material of the charged particles 33 is, for example, titanium dioxide, aluminum oxide, zinc oxide, or the like, but is not limited thereto.

In other embodiments, the polarity and color of the charged particles 33 in the electrophoretic layer 30 are not limited thereto. In particular, the charged particles 33 in the electrophoretic layer 30 may be electrophoretic particles of a single color of a single polarity. The single-polarity, single-color electrophoretic particles may be one of positively charged white electrophoretic particles, positively charged black electrophoretic particles, negatively charged black electrophoretic particles, positively charged colored electrophoretic particles, or negatively charged colored electrophoretic particles. Alternatively, the charged particles 33 in the electrophoretic layer 30 comprise electrophoretic particles of a plurality of colors of a single polarity, i.e. the charged particles 33 in the electrophoretic layer 30 comprise both positively or negatively charged, but the colors comprise at least two or more of black, white, and color. Alternatively still, the charged particles 33 in the electrophoretic layer 30 comprise electrophoretic particles of a plurality of colors of a plurality of polarities, i.e. the charged particles 33 in the electrophoretic layer 30 have more than one polarity (i.e. both positively and negatively charged electrophoretic particles) and more than one color (i.e. at least two of black, white and color in color). In this case, the charged particles 33 in the electrophoretic layer 30 include at least two kinds of electrophoretic particles having different colors and opposite polarities, such as a combination of negatively charged white electrophoretic particles and positively charged black electrophoretic particles.

The second substrate 20 includes a second base 21 and a second common electrode layer 22 on a surface of the second base 21 near the electrophoretic layer 30 side. The second substrate 21 is transparent, and the material of the second substrate 21 is, for example, glass or plastic. The plastic is, for example, polyethylene terephthalate (Poly Ethylene Terephthalate, PET). The second common electrode layer 22 is disposed to face the plurality of pixel electrodes 13 and the first common electrode 14. The second common electrode layer 22 is disposed to cooperate with the pixel electrode 13 and the first common electrode 14 to form an electric field (also referred to as an electric field in a vertical direction, or a vertical electric field, or a longitudinal electric field) along the thickness direction of the electrophoretic display screen 100 within the electrophoretic layer 30.

The material of the second common electrode layer 22 may be a transparent conductive material such as indium tin oxide, indium zinc oxide, or the like. The second common electrode layer 22 is a patterned, non-entirely disposed, discontinuous film layer (also referred to as a patterned layer), and openings are disposed at least at intervals corresponding to the pixel electrode 13 and the first common electrode 14 to enhance the transmittance of the pixel P in the transparent state. Specific patterns of the second common electrode layer 22 will be described in detail below with reference to fig. 3 to 7, which is not mentioned.

The display layer 40 is located on a side of the first substrate 10 remote from the electrophoretic layer 30. The display layer 40 and the first substrate 10 are bonded to each other, for example, by a transparent adhesive layer (not shown). Or the display layer 40 and the first substrate 10 are coupled by a mechanical member (not shown). In the embodiment shown in fig. 2, the display layer 40 is an organic light emitting diode (organic light emitting diode, OLED) display panel. The display layer 40 includes a third substrate 41, a display driving layer 42, a light emitting element layer 43, and a polarizing layer 44, which are sequentially stacked on the third substrate 41. The light emitting element layer 43 includes a plurality of organic light emitting diodes (not shown). The organic light emitting diode may include an anode, a hole transport layer, a light emitting layer, an electron transport layer, a cathode, and the like, which are sequentially formed on the display driving layer.

In other embodiments, the display layer 40 may also be a liquid crystal display panel (liquid crystal display, LCD). The liquid crystal display panel comprises a color filter substrate, an array substrate, a liquid crystal layer, a backlight module, an upper polarizer, a lower polarizer and the like, wherein the color filter substrate and the array substrate are oppositely arranged, the liquid crystal layer is arranged between the color filter substrate and the array substrate, and the backlight module is arranged on one side of the array substrate far away from the color filter substrate. The upper polaroid can be positioned at one side of the color filter substrate far away from the array substrate, and the lower polaroid can be positioned between the backlight module and the array substrate.

The optical state of each pixel P (or the transmittance of each pixel P) may be changed by the movement of the charged particles 33. Specifically, the optical state of each pixel P includes a transparent state (also referred to as a transparent state or a light transmitting state) and an opaque state (also referred to as an opaque state or an opaque state). The transparent state refers to a state in which the movement of the charged particles 33 is controlled by an electric field so that the charged particles 33 move to establish a channel for light passing through the electrophoretic layer 30; the non-transparent state refers to a state in which the movement of the charged particles 33 is controlled by an electric field, and the charged particles 33 are dispersed to block light passing through the electrophoretic layer 30.

In the embodiment shown in fig. 2, the charged particles 33 are white electrophoretic particles. The non-transparent state of each pixel P is a white state (II), and the transparent state of each pixel P includes a display state (I) and a black state (III). Specifically, when the charged particles 33 are accumulated on the pixel electrode 13 and/or the first common electrode 14 in a pixel P (e.g., the leftmost pixel P in fig. 2), and the display layer 40 is turned on and displays, the light L1 emitted from the display layer 40 can be displayed through the electrophoretic layer 30, so that the corresponding pixel P displays the color displayed by the display layer 40. The optical state of the pixel P is referred to herein as the display state. Since the charged particles 33 are deposited on the pixel electrode 13 and/or the first common electrode 14 and a channel through which light from the display layer 40 under the electrophoretic layer 30 is transmitted is formed, this state of the pixel P is also referred to as a transmission state.

In addition, when the charged particles 33 are tiled between the pixel electrode 13 and the first common electrode 14 in a pixel P (e.g., the pixel P located in the middle in fig. 2), the light L2 of the external environment is reflected by the charged particles 33, and the pixel P assumes the color of the charged particles 33, i.e., assumes white. Since the pixel P exhibits a white color, the optical state of the pixel P is referred to herein as white. In addition, since the light of the opposite two electrophoretic layers 30 is blocked by the charged particles 33 in the pixel P and is not transmitted, the optical state of the pixel P is also referred to as an opaque state.

In addition, when the charged particles 33 are accumulated on the pixel electrode 13 and/or the first common electrode 14 in a pixel P (e.g., the rightmost pixel P in fig. 2), and the display layer 40 is turned off, the light L3 of the external environment is absorbed by the light absorbing layer (e.g., the polarizing layer of the organic light emitting display panel or the upper polarizer and the lower polarizer of the liquid crystal display panel) in the display layer 40 through the electrophoretic layer 30, so that the pixel P appears black. Since the pixel P exhibits a black color, the optical state of the pixel P is referred to herein as black. In addition, since the light of the opposite two electrophoretic layers 30 is blocked by the charged particles 33 in the pixel P and is not transmitted, the optical state of the pixel P is also referred to as an opaque state.

In summary, in the case of the charged particles 33 being white electrophoretic particles, the optical state of each pixel P comprises two different transparent states, i.e. a display state (I) and a black state (III), and one non-transparent state, i.e. a white state (II).

In another embodiment, the charged particles 33 may be black electrophoretic particles. The optical state of each pixel P may comprise two different transmissive states (display state and white state) and one non-transmissive state (black state). Specifically, when the charged particles 33 are deposited on the pixel electrode 13 and/or the first common electrode 14 in a pixel P, and the display layer 40 is turned on and displays, the light emitted from the display layer 40 can pass through the electrophoretic layer 30 to display, and the pixel P displays the color displayed by the display layer 40, which is referred to herein as a transparent state, and is referred to herein as a display state. When the charged particles 33 are tiled between the pixel electrode 13 and the first common electrode 14 in a pixel P, the light of the external environment is reflected by the charged particles 33, and the pixel P assumes the color of the charged particles 33, i.e. assumes black. The optical state of the pixel P is referred to herein as the non-transparent state, also referred to as the black state. When a pixel P is formed, the charged particles 33 are deposited on the pixel electrode 13 and/or the first common electrode 14, and white light is emitted from the pixel P unit in the display layer 40 after mixing, so that the pixel P is white. The optical state of the pixel P is referred to herein as the transmissive state, also referred to as the white state. That is, in the case where the charged particles 33 are black electrophoretic particles, the optical state of each pixel P includes two different transparent states (a display state and a white state) and one non-transparent state (a black state).

In yet another embodiment, the charged particles 33 may include charged electrophoretic particles of black and white having opposite polarities. Each of the pixels P may include two different non-transparent states (black and white) and one transparent state (display state). Specifically, when the charged particles 33 are deposited on the pixel electrode 13 and/or the first common electrode 14 in a pixel P, and the display layer 40 is turned on and displays, the light emitted from the display layer 40 can pass through the electrophoretic layer 30 to display, and the pixel P displays the color displayed by the display layer 40, which is referred to herein as a transparent state, and is referred to herein as a display state. When the black charged particles 33 are tiled between the pixel electrode 13 and the first common electrode 14 in a pixel P and are closer to the second substrate 20 than the white charged particles 33, the light of the external environment is reflected by the black charged particles 33, and the pixel P appears black. The optical state of the pixel P is referred to herein as the non-transparent state, also referred to as the black state. When the white charged particles 33 are tiled between the pixel electrode 13 and the first common electrode 14 in a pixel P and are closer to the second substrate 20 than the black charged particles 33, the light of the external environment is reflected by the white charged particles 33, and the pixel P appears white. The optical state of the pixel P is referred to herein as the non-transparent state, also referred to as the white state. That is, in the case where the charged particles 33 include the charged electrophoretic particles of black and the charged electrophoretic particles of white having opposite polarities, the transparent state of each of the pixels P is a display state, and the non-transparent state of each of the pixels P includes a black state and a white state.

In other embodiments, where the charged particles 33 comprise electrophoretic particles of a single color (e.g., red), the pixel P displays the single color (e.g., red) in an optical state of the non-transparent state. In the case that the charged particles 33 include electrophoretic particles of a plurality of colors, if the electrophoretic particles of a plurality of colors are tiled between the pixel electrode 13 and the first common electrode 14 in the optical state of the non-transparent state, the light of the external environment is reflected by the electrophoretic particles of a plurality of colors, and the pixel P presents a composite color of the electrophoretic particles of a plurality of colors.

In a conventional electrophoretic display screen, charged black electrophoretic particles and white electrophoretic particles are enclosed in microcapsules or microcups, so that the charged particles move under the drive of a vertical electric field to realize a black state and a white state. In the conventional electrophoretic display, although colorization can be achieved by a color filter or multicolor particle method, the conventional electrophoretic display has a poor colorization color gamut (about 20% ntsc) and a slow response speed (about 1.5 s) of switching between colors.

In this embodiment of the present application, the electrophoretic display 100 adopts a lateral driving technology, and compared with a conventional electrophoretic display, in-plane electrodes (i.e., a pixel electrode and a first common electrode) are added, and particles are collected at the positions of the pixel electrode 13 and/or the first common electrode 14 by driving with a lateral electric field, so that three states of black state, white state and display state are switched. In addition, in the embodiment of the present application, when the electrophoretic display screen 100 includes the display layer 40, the technology of lateral driving and the technology of OLED or LCD are combined to realize hybrid display, so that the electrophoretic display screen 100 has both the display effect of power saving and eye protection of the electrophoretic display and the good color display effect of the OLED/LCD in the transparent state. In other embodiments, electrophoretic display 100 may not include display layer 40.

As discussed above, the electrophoretic display panel driven in the lateral direction in the related art has a problem of low light transmittance of the pixels in a transparent state and a problem of moire. In order to make the electrophoretic display screen have higher light transmittance in the transparent state, after the charged particles are accumulated on the in-plane electrode, the transparent state display effect of the pixel is better. In some embodiments, the second common electrode layer is randomly patterned, and the pattern of the second common electrode layer is a random, non-periodic pattern. Therefore, the phenomenon of moire can be avoided while the transmittance of the electrophoretic display screen in the transparent state is improved. Or, the second common electrode layer is randomly patterned, and the light transmittance of the second common electrode layer can be improved on the premise of not introducing mole patterns.

The arrangement of the second common electrode layer on the second substrate in the different embodiments of the present application is specifically described below with reference to fig. 3 to 7. The pattern of the second common electrode layer 22 in fig. 2 may be a periodic pattern or an aperiodic pattern. Specifically, the periodic pattern may be as the pattern of the second common electrode layer 22a shown in fig. 3, but is not limited thereto. The non-periodic pattern may be any one of the pattern of the second common electrode layer 22b shown in fig. 5, the pattern of the second common electrode layer 22c shown in fig. 6, and the pattern of the second common electrode layer 22d shown in fig. 7, but is not limited thereto. In some embodiments, no matter the pattern of the second common electrode layer is a periodic pattern or an aperiodic pattern, the difference of the transmittance of the second common electrode layer to visible light is not greater than 1% corresponding to different pixels, so as to ensure the uniformity of the display effect of each pixel in the transparent state.

As shown in fig. 3, the pattern of the second common electrode layer 22a is regularly arranged or periodically arranged. Specifically, the second common electrode layer 22a includes a plurality of openings H arranged at an array interval. Each of the plurality of openings H is substantially square. The plurality of openings H are arranged in a plurality of rows along the first direction D1 and in a plurality of rows along the second direction D2. The first direction D1 is perpendicular to the second direction D2. The pattern of the second common electrode layer 22a is in a crisscrossed grid shape.

As shown in fig. 4, the opening H penetrates opposite surfaces of the second common electrode 221. A space G is provided between the pixel electrode 13 and the first common electrode 14. The openings H comprise at least portions arranged in correspondence with the spaces G such that the projections of the openings H on the first substrate 10 at least partially cover the spaces G in the thickness direction of the electrophoretic display. When the pixel is in the transparent optical state, the light from the first substrate 10 side can pass through the second substrate 21 from the opening H of the second common electrode layer 22a to the display side at the interval G, so that the light transmittance of the pixel in the transparent state is improved compared with the case that the second common electrode layer is arranged in the whole surface.

It should be noted that the size of the opening H may be the same as the size of the interval G to maximize the transmittance of the pixel in the transparent state, but is not limited thereto. The size of the openings H may also be smaller than the interval G, or one interval G corresponds to a plurality of openings H.

In other embodiments, the pattern of the second common electrode layer may be other periodically arranged patterns or other regularly arranged patterns. For example, the second common electrode layer includes a plurality of openings arranged at intervals. Each opening may be in an irregular pattern or other regular patterns (such as a circle, a triangle, a trapezoid, etc.) except for a rectangle, and the plurality of openings are periodically arranged, and the projection of the opening on the first substrate at least partially covers the interval between the pixel electrode and the first common electrode, so as to improve the transmittance of the pixel in a transparent state.

Fig. 5 is a schematic layout diagram of a second common electrode layer on a second substrate according to another embodiment of the present application. As shown in fig. 5, the second common electrode layer 22b includes electrode stripes 223 that are non-periodically distributed to avoid the phenomenon of moire while enhancing the transmittance of the electrophoretic display screen in a transparent state. Wherein the electrode stripe 223 defines a plurality of openings H. Each of the openings H penetrates through opposite surfaces of the second common electrode layer 22b and exposes a surface of the second substrate 21. The electrode stripes 223 are staggered, and each electrode stripe 223 is linear. The extending direction and the inclination angle of the electrode stripes 223 are random and irregular, so that the distribution of the plurality of openings H in the second common electrode layer 22b is random and irregular, and the shape of each opening H has triangle, quadrangle and other polygons. Each of the spaces G may correspond to one or more openings H, that is, the projection of at least one opening H on the second common electrode layer 22b on the first substrate covers the space G, so as to improve the transmittance of the pixel in the transparent state. The second common electrode layer 22b may correspond to all pixels in the electrophoretic display. In the embodiment shown in fig. 5, although the distribution of the openings H in the second common electrode layer 22b is random, the transmittance of the second common electrode layer 22b to visible light at each position is substantially equivalent, and uniformity of the display effect of each pixel in the transparent state can be ensured.

Fig. 6 is a schematic layout diagram of a second common electrode layer on a second substrate according to another embodiment of the present application. As shown in fig. 6, the second common electrode layer 22c is different from the second common electrode layer 22b in that: the light transmittance at different positions of the second common electrode layer 22c may have a difference. Specifically, the pattern of the second common electrode layer 22c is a pattern of light paths where a plurality of point light sources having the same optical density are randomly distributed around a position and exit toward the position. Herein, point light sources having the same optical density refer to light sources that emit light uniformly in all directions from one point to the surrounding space. The second common electrode layer 22c is a transparent conductive layer (such as indium tin oxide) and is patterned. By designing the pattern of the mask plate used in the patterning process to be a non-periodic pattern, the second common electrode layer 22c includes non-periodically arranged, randomly staggered electrode stripes 223. The design idea of the pattern of the mask is that a plurality of point light sources with the same optical density are randomly arranged at the periphery of a position, the point light sources with the same optical density are emitted into the position from the periphery, and the light paths of the point light sources with the same optical density are used as the pattern of the mask, or the light paths of the point light sources with the same optical density are used as the pattern formed by a plurality of electrode stripes 223 in the second common electrode layer 22 c. Since the pattern of the second common electrode layer 22c has the openings H, and the pattern of the second common electrode layer 22c is non-periodically arranged, the phenomenon of moire can be avoided while the transmittance of the electrophoretic display screen in the transparent state is improved.

Fig. 7 is a schematic layout diagram of a second common electrode layer on a second substrate according to another embodiment of the present application. As shown in fig. 7, the light transmittance at different positions of the second common electrode layer 22d has a difference. The pattern of the second common electrode layer 22d is a pattern of light paths where a plurality of point light sources having the same optical density are uniformly distributed around a position and exit toward the position. Similar to the embodiment shown in fig. 6, the second common electrode layer 22d may also be a transparent conductive layer (e.g., indium tin oxide) patterned. By designing the pattern of the mask plate used in the patterning process to be a non-periodic pattern, the second common electrode layer 22d includes non-periodically arranged electrode stripes 223. In the embodiment shown in fig. 7, the design concept of the pattern of the mask plate is to use a plurality of point light sources with the same optical density to be uniformly arranged at the periphery of a position, and make the plurality of point light sources with the same optical density shoot into the position from the periphery, and take the light paths of the plurality of point light sources with the same optical density as the pattern of the mask plate, or take the light paths of the plurality of point light sources with the same optical density as the pattern formed by the plurality of electrode stripes 223 in the second common electrode layer 22 d. Since the pattern of the second common electrode layer 22d has the openings H, and the pattern of the second common electrode layer 22d is non-periodically arranged, the phenomenon of moire can be avoided while the transmittance of the electrophoretic display screen in the transparent state is improved. In addition, uniformity of light transmittance at different positions of the second common electrode layer 22d is improved compared to the embodiment shown in fig. 6.

In the above embodiment, the pattern of the second common electrode layer includes the linearly extending electrode stripes which are randomly distributed, but is not limited thereto. In other embodiments, the pattern of the second common electrode layer includes one or a combination of several of a dot pattern, a line pattern, and a planar pattern, which are randomly distributed. Alternatively, the second common electrode layer includes a plurality of the openings distributed randomly, and each of the openings has a random pattern. Specifically, the outline of the second common electrode layer defining the shape of the opening is random, and the pattern of the opening may be regular or irregular. The dot pattern does not limit the pattern to be circular, but means that the two-dimensional size of the pattern is small. The dot pattern may be regular round, rectangular, etc., or randomly generated. The line pattern is not limited to a straight line segment, but means that the pattern varies greatly in the ratio of width to length. The linear pattern may be a regular linear segment, an arc segment, or the like, or may be a randomly generated linear pattern. The planar pattern refers to a pattern with a larger two-dimensional size, and the pattern can be in a regular shape (such as a rectangular block shape) or a randomly generated shape.

The second common electrode layer of the embodiment of the application can be prepared through patterning processes of photoetching, developing and etching. The patterning process specifically includes the following steps S1 to S8.

Step S1: the substrate on which the conductive layer is formed is subjected to a pretreatment. The conductive layer is, for example, crystallized indium tin oxide, the substrate is, for example, light-transmitting glass, and the substrate is, for example, a square of 5cm×5cm, but is not limited thereto. Step S1 specifically includes sequentially performing ultrapure water cleaning on the substrate on which the conductive layer is formed, then performing ultrasonic treatment in NaOH solution with ph=10 for 10min, performing ultrasonic treatment with acetone for 10min, anhydrous ethanol for 10min, and deionized water for 10min, performing surface hydrophilic treatment, and performing plasma treatment for 5min or OZONE (UV-OZONE) treatment for 20min.

Step S2: and (5) spin-coating. Step S2 specifically includes forming a photoresist on a side of the conductive layer away from the substrate, and rotating at 1000rpm for 10S and then at 1500rpm for 40S. The photoresist may be a forward photoresist, but is not limited thereto.

Step S3: and (5) pre-baking. Step S3 specifically includes heating at 120℃for 2min, but is not limited thereto.

Step S4: and (5) exposing. Step S4 specifically includes, but is not limited to, contact exposure with a designed reticle, exposure time 26S.

Step S5: and (5) developing. Step S5 specifically includes, but is not limited to, stationary development using a developer for about 150S.

Step S6: and (5) post-baking. Step S6 specifically includes heating to cure the photoresist.

Step S7: etching. Step S7 specifically comprises using concentrated hydrochloric acid (34% -36% by volume) and pure water 1:1, mixing and etching, namely tilting the substrate, placing the surface where the conductive layer is positioned downwards, and etching for about 3 minutes while oscillating.

Step S8: and (5) removing photoresist. Step S8 specifically includes soaking with acetone for about 2min, and removing the photoresist to obtain a patterned conductive layer. The substrate is a second substrate, the patterned conductive layer is a second common electrode layer, and patterns of the mask plate in step S4 are different, and finally obtained patterns of the second common electrode layer are also different.

In one embodiment, in step S1, the substrate is transparent glass, the conductive layer is indium tin oxide with a thickness of 30nm crystallized on the whole, and the total transmittance of visible light is 85.25%. The mask plate in step S4 is a square array pattern, and after step S8, the second common electrode layer is a pattern as shown in fig. 3, and the total transmittance of visible light is 91.11%, the scattered transmittance is 0.41%, and the haze is 0.45. It can be seen that the total light transmittance is improved by approximately 6% compared to the case where the second common electrode layer is provided over the entire surface.

In another embodiment, in step S1, the substrate is transparent glass, the conductive layer is indium tin oxide with a thickness of 30nm crystallized on the whole, and the total transmittance of visible light is 85.57%. The mask plate in the step S4 has a random pattern, and after the step S8, the second common electrode layer has a pattern as shown in fig. 6, and the total transmittance of visible light is 91.52%, the scattered transmittance is 0.20%, and the haze is 0.45. It can be seen that the total light transmittance is improved by approximately 6% and the occurrence of moire can be avoided to some extent, compared with the case where the second common electrode layer is provided over the entire surface.

In yet another embodiment, in step S1, the substrate is transparent glass, the conductive layer is a 30nm thick crystallized indium tin oxide, and the total transmittance of visible light is 85.25%. The mask plate in the step S4 has a random pattern, and after the step S8, the second common electrode layer has a pattern as shown in fig. 7, and the total transmittance of visible light is 91.17%, the scattered transmittance is 0.22%, and the haze is 0.25. It can be seen that the total light transmittance is improved by approximately 6% and the occurrence of moire can be avoided to some extent, compared with the case where the second common electrode layer is provided over the entire surface.

In summary, in the embodiment of the present application, the second common electrode layer is a patterned conductive layer, and is not disposed on the whole surface, so that the total light transmittance of the second common electrode layer under visible light is improved. When the pattern of the second common electrode layer is a random disordered pattern or a non-periodic distribution pattern, the whole light transmittance of the electrophoretic display screen is improved, and meanwhile, the mole patterns caused between the periodic patterned second common electrode layer and the bottom periodic pixel electrode can be reduced.

Note that, in the embodiment of the present application, the pattern of the pixel electrode and the first common electrode on the first substrate is not limited. The pixel electrode and the first common electrode on the first substrate may be any pattern of laterally drivable electrodes.

Fig. 8A is a schematic layout diagram of a pixel electrode and a first common electrode in an embodiment of the present application. As shown in fig. 8A, the pixel electrode 13a and the first common electrode 14a are each in a linear pattern. Between two adjacent pixel electrodes 13a, there is a first common electrode 14a. The pixel electrode 13a and the first common electrode 14a are disposed at intervals along the first direction D1, and have an interval G. In the second direction D2, each of the pixel electrode 13a and the first common electrode 14a extends in an elongated shape. The widths of the pixel electrode 13a and the first common electrode 14a are, for example, 0.2mm, and the interval between the pixel electrode 13a and the first common electrode 14a is, for example, 0.2mm, but not limited thereto.

In other embodiments, each pixel electrode corresponds to one first common electrode. The pixel electrode and the first common electrode are not limited to be in a linear pattern. For example, the pixel electrode and/or the first common electrode may be a comb-like structure (also referred to as an interdigital structure) having a plurality of branches. Fig. 8B is a schematic layout diagram of a pixel electrode and a first common electrode according to another embodiment of the present application. As shown in fig. 8B, the pixel electrode 13B is an interdigital electrode. The first common electrode 14b is in a linear pattern. The pixel electrode 13b includes two first branches 131 and a first connection portion 132 connecting the two first branches 131. The two first branches 131 are spaced apart along the first direction D1 and extend along the second direction D2. The first common electrode 14b includes a second branch 141 extending in the same direction as the first branches 131, and the second branch 141 is located between the two first branches 131 and forms a gap G with the first branch 131 adjacent thereto.

Fig. 8C is a schematic layout diagram of a pixel electrode and a first common electrode according to another embodiment of the present application. As shown in fig. 8C, the pixel electrode 13C and the first common electrode 14C are both interdigital. The pixel electrode 13c includes two first branches 131 and a first connection portion 132 connecting the two first branches 131. The two first branches 131 are spaced apart along the first direction D1 and extend along the second direction D2. The first common electrode 14c includes two second branches 141 extending in the same direction as the first branches 131, and a second connection portion 142 connecting the two second branches 141. In the first direction D1, the pixel electrode 13c and the corresponding first common electrode 14c are arranged in such a manner that one first branch 131 and one second branch 141 are alternately arranged. A space G is formed between each first branch 131 and the second branch 141 immediately adjacent thereto.

In fig. 8A to 8C, the size, shape, and arrangement of the pixel electrodes are one example, and the size, shape, and arrangement of the first common electrode are one example, and in other embodiments, the size, shape, and arrangement may be changed.

The embodiment of the application also provides a display device, which comprises the electrophoresis display screen 100. The display device can be various products or components with display functions, such as electronic tags, wearable equipment (e.g. a watch), electronic readers, navigator, electronic photo frames, advertisement boards in commercial supermarkets and the like, and the specific application scene of the display device is not limited.

The above embodiments are only for illustrating the technical solution of the present application and not for limiting, and although the present application has been described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or substituted without departing from the spirit and scope of the technical solution of the present application.

Claims

1. An electrophoretic display screen, comprising:

2. The electrophoretic display screen of claim 1, wherein the second common electrode layer is a patterned layer and the pattern of the second common electrode layer is a non-periodic pattern.

3. An electrophoretic display screen according to claim 2, wherein the second common electrode layer comprises a plurality of the apertures distributed randomly, each aperture having a random pattern.

4. The electrophoretic display screen of claim 2, wherein the pattern of the second common electrode layer comprises one or a combination of several of a random dot pattern, a line pattern, and a planar pattern.

5. The electrophoretic display screen of claim 1, wherein the second common electrode layer is a patterned layer and the pattern of the second common electrode layer is a periodic pattern.

6. An electrophoretic display screen according to claim 5 wherein the second common electrode layer comprises a plurality of the apertures arranged in spaced relation.

7. The electrophoretic display screen of claim 6, wherein a plurality of the openings are arranged in an array.

8. An electrophoretic display screen according to any of claims 1 to 7, comprising a plurality of pixels, the second common electrode layer corresponding to all of the plurality of pixels, wherein the difference in transmittance of visible light of the second common electrode layer is not more than 1% for different ones of the pixels.

9. An electrophoretic display screen according to any of claims 1 to 7, wherein the charged particles comprise electrophoretic particles of a single color of a single polarity; alternatively, the charged particles comprise electrophoretic particles of a plurality of colors of a single polarity; alternatively, the charged particles comprise electrophoretic particles of a plurality of colors of a plurality of polarities.

10. An electrophoretic display screen according to any one of claims 1 to 7, comprising a plurality of pixels, each of the pixels corresponding to at least one of the pixel electrodes and one of the first common electrodes.

11. The electrophoretic display screen of claim 10, wherein the electrophoretic layer further comprises a plurality of micro-cup structures, an inner space of each micro-cup structure being formed as a receiving cavity, the charged particles being located in the receiving cavities, each receiving cavity corresponding to at least one of the pixels.

12. An electrophoretic display screen as claimed in claim 11, further comprising a display layer on a side of the pixel electrode remote from the electrophoretic layer.

13. The electrophoretic display screen of claim 12, wherein in the case of the charged particles being white electrophoretic particles, the non-transparent state of each of the pixels is a white state, the transparent state of each of the pixels comprises a black state and a display state;

alternatively, in the case that the charged particles are black electrophoretic particles, the non-transparent state of each pixel is a black state, and the transparent state of each pixel includes a white state and a display state;

Alternatively, in the case where the charged particles include charged electrophoretic particles of black and white having opposite polarities, the non-transparent state of each of the pixels includes a black state and a white state, and the transparent state of each of the pixels is a display state.

14. An electrophoretic display screen according to claim 13, wherein each of the pixel electrodes and each of the first common electrodes are elongated extending in the same direction, and one of the first common electrodes is provided between two adjacent pixel electrodes.

15. An electrophoretic display screen according to claim 13, wherein each of the pixel electrodes comprises a plurality of first branches, each of the first common electrodes comprises at least one second branch having the same extension direction as the first branch, and each of the pixel electrodes and a corresponding one of the first common electrodes are arranged in such a manner that one of the first branches and one of the second branches are alternately arranged.

16. A display device comprising an electrophoretic display screen according to any one of claims 1 to 15.