Multi-particle electrophoretic display with low flicker image update

Abstract

Electrophoretic displays with multi-particle electrophoretic media, and improved methods for driving such multi-particle electrophoretic media, in particular methods using active matrix backplanes and controllers. These driving methods use faster gate updates, and for a given pixel, groups of gate updates have different gaps between each other. These methods can be popularized to any electrophoretic display using push-pull waveforms, particularly suitable for novel multi-particle electrophoretic displays capable of producing four or more colors per pixel. By means of the method, the display effect of the electrophoretic display will not flicker compared with the traditional line-by-line constant frame spacing updating addressing.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 523541, filed June 27, 2023. All patents and publications disclosed herein are incorporated herein by reference in their entirety. Background Technology

[0003] Electrophoretic displays (EPDs) change color by altering the position of one or more charged colored particles relative to a light-transmitting viewing surface. These EPDs are often referred to as "electronic paper" or "ePaper" because the resulting displays have high contrast and are readable in sunlight, much like ink on paper. EPDs are widely used in e-readers because they provide a book-like reading experience, consume little power, and allow users to carry hundreds of books in a lightweight handheld device. These devices are increasingly being used to display out-of-home (OOH) digital content, such as shelf labels, outdoor advertising, and traffic signs.

[0004] For many years, electrophoretic displays have contained only two types of charged colored particles: black and white. (To be sure, the term "colored" as used herein includes both black and white.) White particles are typically light-scattering and include, for example, titanium dioxide, while black particles are absorbent in the visible spectrum and can include carbon black or absorbing metal oxides such as copper chromite. In its simplest sense, a monochrome electrophoretic display requires only a light-transmitting electrode at the viewing surface, a back electrode, and an electrophoretic medium containing white and black particles with opposite charges. When a voltage of one polarity is applied, the white particles move to the viewing surface; when a voltage of the opposite polarity is applied, the black particles move to the viewing surface. If the back electrode contains controllable regions (pixels)—segmented electrodes or an active matrix of pixel electrodes controlled by transistors—a pattern can be made to appear electronically at the viewing surface. This pattern could be, for example, text in a book.

[0005] Recently, multiple color options have been commercially used in electrophoretic displays, including tri-color displays (black, white, red; black, white, yellow) and quad-color displays (black, white, red, yellow). Similar to the operation of a black-and-white electrophoretic display, electrophoretic displays with three or four reflective particles operate much like a simple black-and-white display because the desired color particles are driven onto the viewing surface. The driving scheme is far more complex than that with only black and white, but ultimately, the light function of the particles is the same.

[0006] Advanced Color Electronic Paper (ACeP) TMThis also includes four types of particles, but the cyan, yellow, and magenta particles are subtractive rather than reflective, thus allowing thousands of colors to be produced at each pixel. Color processing is functionally equivalent to the printing methods long used in offset and inkjet printers. A given color is produced by using the correct ratio of cyan, yellow, and magenta on a bright white paper background. In the case of ACeP, the relative positions of the cyan, yellow, magenta, and white particles relative to the viewing surface determine the color at each pixel. While this type of electrophoretic display allows for the display of thousands of colors at each pixel, careful control of the position of each pigment (50 to 500 nanometers in size) within a working space approximately 10 to 20 micrometers thick is crucial. Clearly, variations in particle position will result in an incorrect color being displayed at a given pixel. Therefore, this system requires precise voltage control. Further details of the system are available in the following U.S. patents, all of which are incorporated herein by reference in their entirety: U.S. Patent Nos. 9,361,836, 9,921,451, 10,276,109, 10,353,266, 10,467,984, 10,593,272, and 10,657,869.

[0007] As described in the aforementioned patent, the waveform (i.e., the electric field provided on the electrophoretic medium as a function of time) typically requires significant oscillations in voltage polarity over a short period. Therefore, in some instances, color electrophoretic displays exhibit "flickering," "flickering," or "appearing to flicker" when switching between color images. This drawback is particularly pronounced when full-color e-readers switch between full-color images rapidly (i.e., within less than one second). A solution for reducing flicker in multi-particle electrophoretic displays, such as ACEP displays, is presented below.

[0008] This invention relates to color electrophoretic displays, and more particularly (but not limited to) electrophoretic displays capable of displaying two or more colors using a single layer of electrophoretic material comprising multiple colored particles, such as white, cyan, yellow, and magenta particles. In some instances, two particles are positively charged and one (or two) particles are negatively charged. In some instances, one particle is positively charged and three particles are negatively charged. In some instances, one particle is negatively charged and three particles are positively charged. These particles may also differ in the type of charge on the particle surface and / or the type of polymer used for surface functionalization. These particles may contain organic or inorganic pigments or dyes.

[0009] The term "grayscale state" is used herein in its conventional meaning within the field of imaging, referring to a state between two extreme optical states of a pixel, and does not necessarily imply a black-to-white transition between these two extreme states. For example, several IENK patents and published applications mentioned below describe electrophoretic displays where the extreme states are white and dark blue, making the intermediate "grayscale state" actually a pale blue. In fact, as previously stated, a change in optical state may not be a change in color at all. The terms "black" and "white" can be used below to refer to two extreme optical states of a display and should be understood to generally include extreme optical states that are not strictly black and white, such as the white and dark blue states mentioned above.

[0010] The terms “bistable” and “bistable” are used herein in their conventional sense to refer to a display comprising display elements having a first display state and a second display state that are different in at least one optical characteristic, such that after any given element is driven to present its first or second display state by means of an addressing pulse of finite duration, the state will persist for at least several times (e.g., at least four times) the shortest addressing pulse duration required to change the state of the display element after the addressing pulse terminates. As shown in U.S. Patent No. 77,170,670, some particle-based electrophoretic displays capable of supporting grayscale are stable not only in their extreme black and white states but also in their intermediate grayscale states, as are some other types of electro-optical displays. This type of display is properly referred to as “multistable” rather than bistable; however, for convenience, the term “bistable” may be used herein to encompass both bistable and multistable displays.

[0011] The term "impulse" is used to refer to driving an electrophoretic display, and in this paper, it refers to the integral of the applied voltage with respect to time during the period when the display is driven.

[0012] Particles that absorb, scatter, or reflect light across a wide band or a selected wavelength are referred to herein as colored particles or pigment particles. Various light-absorbing or light-reflecting materials other than pigments (strictly speaking, this term refers to insoluble colored materials), such as dyes or photonic crystals, can also be used in the electrophoretic media and displays of this invention.

[0013] For many years, particle-based electrophoretic displays have been a subject of in-depth research and development. In these displays, multiple charged particles (sometimes called pigment particles) move through a fluid under the influence of an electric field. Compared to liquid crystal displays (LCDs), electrophoretic displays offer advantages such as good brightness and contrast, wide viewing angles, state bistability, and low power consumption. However, long-term image quality issues have hindered their widespread use. For example, the particles that make up electrophoretic displays tend to settle, leading to insufficient lifespan for these displays.

[0014] As mentioned above, the electrophoretic medium requires the presence of a fluid. In most prior art electrophoretic media, this fluid is a liquid, but a gaseous fluid can be used to generate the electrophoretic medium; see, for example, Kitamura, T. et al., “Electricaltoner movement for electronic paper-like display,” IDW Japan, 2001, Paper HCS1-1, and Yamaguchi, Y. et al., “Toner display using insulative particles charged triboelectrically,” IDW Japan, 2001, Paper AMD4-4. See also U.S. Patents 7,321,459 and 7,236,291. When such gas-based electrophoretic media are used in a direction that allows particle settling, such as in the case of a medium located in a vertical plane, such media appear to be as susceptible to the same type of problems arising from particle settling as liquid-based electrophoretic media. In fact, particle sedimentation appears to be a more serious problem in gas-based electrophoresis media than in liquid-based electrophoresis media, because the lower viscosity of gaseous suspensions allows electrophoretic particles to settle more quickly compared to liquid suspensions.

[0015] Numerous patents and applications assigned to or in the name of MIT and Einkel describe various techniques used in encapsulated electrophoresis and other electro-optic media. Such encapsulation media comprise a plurality of small capsules, each capsule itself comprising an inner phase containing electrophoretically moving particles in a fluid medium and a capsule wall surrounding that inner phase. Typically, the capsules themselves are held in a polymer binder to form a coherent layer located between two electrodes. The techniques described in these patents and applications include:

[0016] (a) Electrophoretic particles, fluids, and fluid additives; see, for example, U.S. Patent Nos. 7,002,728 and 7,679,814;

[0017] (b) Encapsulation, adhesives, and encapsulation processes; see, for example, U.S. Patent Nos. 6,922,276 and 7,411,719;

[0018] (c) Microunit structures, wall materials, and methods of forming microunits; see, for example, U.S. Patent Nos. 7,072,095 and 9,279,906;

[0019] (d) Methods for filling and sealing microcells; see, for example, U.S. Patent Nos. 7,144,942 and 7,715,088;

[0020] (e) Thin films and subassemblies containing electro-optic materials; see, for example, U.S. Patent Nos. 6,982,178 and 7,839,564;

[0021] (f) Backplanes, adhesive layers and other auxiliary layers used in displays and methods thereof; see, for example, U.S. Patent Nos. 7,116,318 and 7,535,624;

[0022] (g) Color Formation and Color Adjustment; see, for example, U.S. Patent Nos. 6,017,584; 6,545,797; 6,664,944; 6,788,452; 6,864,875; 6,914,714; 6,972,893; 7,038,656; 7,038,670; 7,046,228; 7,052,571; 7,075,502; 7,167,155; 7,385,751; 7,492,505; 7,667,684; 7,684,108; 7,791,789; 7,800,813; 7,821,702; 7,839,564; 7,910,175; 7,952,790; 7,956,841; 7,982,941; 8,040,594; 8,054,526; 8,098,418; 8,159,636; 8,213,076; 8,363,299; 8,422,116; 8,441,714; 8,441,716; 8,466,852; 8,503,063; 8,576,470; 8,576,475; 8,593,721; 8,605,354; 8,649,084; 8,670,174; 8,704,756; 8,717,664; 8,786,935; 8,797,634; 8,810,899; 8,830,559; 8,873,129; 8,902,153; 8,902,491; 8,917,439; 8,964,282; 9,013,783; 9,116,412; 9,146,439; 9,164,207; 9,170,467; 9,170,468; 9,182,646; 9,195,111; 9,199,441; 9,268,191; 9,285,649;9,293,511; 9,341,916; 9,360,733; 9,361,836; 9,383,623; and 9,423,666; and U.S. Patent Application Publication Nos. 2008 / 0043318; 2008 / 0048970; 2009 / 0225398; 2010 / 0156780; 2011 / 0043543; 2012 / 0326957; 2013 / 0242378; 2013 / 0278995; 2014 / 0055840; 2014 / 0078576; 2014 / 0340430; 2014 / 0340736; 2014 / 0362213; 2015 / 0103394; 2015 / 0118390; 2015 / 0124345; 2015 / 0198858; 2015 / 0234250; 2015 / 0268531; 2015 / 0301246; 2016 / 0011484; 2016 / 0026062; 2016 / 0048054; 2016 / 0116816; 2016 / 0116818; and 2016 / 0140909;

[0023] (h) A method for driving a display; see, for example, U.S. Patent Nos. 5,930,026; 6,445,489; 6,504,524; 6,512,354; 6,531,997; 6,753,999; 6,825,970; 6,900,851; 6,995,550; 7,012,600; 7,023,420; 7,034,783; 7,061,166; 7,061,662; 7,116,466; 7,119,772; 7,177,066; 7,193,625; 7,202,847; 7,242,514; 7,259,744; 7,304,787; 7,312,794; 7,327,511; 7,408,699; 7,453,445; 7,492,339; 7,528,822; 7,545,358; 7,583,251; 7,602,374; 7,612,760; 7,679,599; 7,679,813; 7,683,606; 7,688,297; 7,729,039; 7,733,311; 7,733,335; 7,787,169; 7,859,742; 7,952,557; 7,956,841; 7,982,479; 7,999,787; 8,077,141; 8,125,501; 8,139,050; 8,174,490; 8,243,013; 8,274,472; 8,289,250; 8,300,006; 8,305,341; 8,314,784; 8,373,649; 8,384,658; 8,456,414; 8,462,102; 8,514,168; 8,537,105; 8,558,783; 8,558,785; 8,558,786; 8,558,855; 8,576,164; 8,576,259; 8,593,396; 8,605,032; 8,643,595; 8,665,206; 8,681,191; 8,730,153; 8,810,525; 8,928,562; 8,928,641; 8,976,444; 9,013,394; 9,019,197; 9,019,198; 9,019,318; 9,082,352; 9,171,508; 9,218,773; 9,224,338; 9,224,342;9,224,344; 9,230,492; 9,251,736; 9,262,973; 9,269,311; 9,299,294; 9,373,289; 9,390,066; 9,390,661; and 9,412,314; and U.S. Patent Application Publication Nos. 2003 / 0102858; 2004 / 0246562; 2005 / 0253777; 2007 / 0091418; 2007 / 0103427; 2007 / 0176912; 2008 / 0024429; 2008 / 0024482; 2008 / 0136774; 2008 / 0291129; 2008 / 0303780; 2009 / 0174651; 2009 / 0195568; 2009 / 0322721; 2010 / 0194733; 2010 / 0194789; 2010 / 0220121; 2010 / 0265561; 2010 / 0283804; 2011 / 0063314; 2011 / 0175875; 2011 / 0193840; 2011 / 0193841; 2011 / 0199671; 2011 / 0221740; 2012 / 0001957; 2012 / 0098740; 2013 / 0063333; 2013 / 0194250; 2013 / 0249782; 2013 / 0321278; 2014 / 0009817; 2014 / 0085355; 2014 / 0204012; 2014 / 0218277; 2014 / 0240210; 2014 / 0240373; 2014 / 0253425; 2014 / 0292830; 2014 / 0293398; 2014 / 0333685; 2014 / 0340734; 2015 / 0070744; 2015 / 0097877; 2015 / 0109283; 2015 / 0213749; 2015 / 0213765; 2015 / 0221257; 2015 / 0262255; 2015 / 0262551; 2016 / 0071465; 2016 / 0078820; 2016 / 0093253; 2016 / 0140910; and 2016 / 0180777 (these patents and patent applications may be referred to hereinafter as MEDEOD (Methods for Driving Electro-optic Displays) applications);

[0024] (i) Applications of displays; see, for example, U.S. Patent Nos. 7,312,784 and 8,009,348; and

[0025] (j) Non-electrophoretic displays, as described in U.S. Patent No. 6,241,921, U.S. Patent Application Publication No. 2015 / 0277160, and U.S. Patent Application Publication Nos. 2015 / 0005720 and 2016 / 0012710.

[0026] Many of the aforementioned patents and applications recognize that the walls surrounding discrete microcapsules in an encapsulated electrophoretic medium can be replaced by a continuous phase, thereby producing a so-called polymer dispersion electrophoretic display, wherein the electrophoretic medium comprises a plurality of discrete electrophoretic fluid droplets and a continuous phase of polymeric material, and the discrete electrophoretic fluid droplets within such a polymer dispersion electrophoretic display can be considered as capsules or microcapsules, even without a discrete capsule membrane associated with each individual droplet; see, for example, U.S. Patent No. 6,866,760. Therefore, for the purposes of this application, such polymer dispersion electrophoretic media are considered a subclass of encapsulated electrophoretic media.

[0027] One related type of electrophoretic display is the so-called microcell electrophoretic display. In a microcell electrophoretic display, charged particles and fluid are not encapsulated in microcapsules, but are retained within multiple cavities formed within a carrier medium (typically a polymer membrane). See, for example, U.S. Patent Nos. 6,672,921 and 6,788,449.

[0028] Although electrophoretic media are typically opaque (because, for example, in many electrophoretic media, particles essentially block visible light from passing through the display) and operate in reflective mode, many electrophoretic displays can operate in so-called shutter mode, where one display state is essentially opaque and the other is transparent. See, for example, U.S. Patent Nos. 5,872,552, 6,130,774, 6,144,361, 6,172,798, 6,271,823, 6,225,971, and 6,184,856. Dielectrophoretic displays, similar to electrophoretic displays but dependent on changes in electric field strength, can operate in a similar mode; see U.S. Patent No. 4,418,346. Other types of electro-optic displays can also operate in shutter mode. Electro-optic media operating in shutter mode can be used in multilayer structures for full-color displays; in such structures, at least one layer adjacent to the viewing surface of the display operates in shutter mode to expose or conceal a second layer farther from the viewing surface.

[0029] Encapsulated electrophoretic displays typically do not suffer from the aggregation and sedimentation failure modes of conventional electrophoretic apparatus and offer further advantages such as the ability to print or coat displays on a variety of flexible and rigid substrates (the term "printing" is used to include all forms of printing and coating, including but not limited to: pre-quantity coating, such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coating, such as blade roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; screen printing; electrostatic printing; thermal printing; inkjet printing; electrophoretic deposition (see U.S. Patent No. 7339715); and other similar techniques). Therefore, the resulting display can be flexible. Furthermore, since the display medium can be printed (using various methods), the display itself can be manufactured inexpensively.

[0030] As mentioned above, most simple existing electrophoretic media essentially display only two colors. Such electrophoretic media either use a single type of electrophoretic particles with a first color in a colored fluid with a second, different color (in this case, the first color is displayed when the particles are near the viewing surface of the display, and the second color is displayed when the particles are spaced apart from the viewing surface), or use first and second types of electrophoretic particles with different first and second colors in a colorless fluid (in this case, the first color is displayed when the first type of particles are near the viewing surface of the display, and the second color is displayed when the second type of particles are near the viewing surface). Typically, these two colors are black and white. If a full-color display is required, an array of color filters can be placed on the viewing surface of a monochrome (black and white) display. Displays with color filter arrays rely on area sharing and color mixing to generate color stimuli. The available display area is shared by three or four primary colors (such as red / green / blue (RGB) or red / green / blue / white (RGBW)), and the filters can be arranged in a one-dimensional (stripes) or two-dimensional (2x2) repeating pattern. Other options for primary colors or more than three primary colors are also known in the art. Three (in the case of RGB displays) or four (in the case of RGBW displays) subpixels are chosen to be small enough that, at the expected viewing distance, they visually blend together to form a single pixel with uniform color stimulation (“color mixing”). An inherent drawback of area sharing is that colorant is always present, and colors can only be modulated by switching the corresponding pixels of the underlying monochrome display to white or black (turning the corresponding primary color on or off). For example, in an ideal RGBW display, red, green, blue, and white primary colors each occupy a quarter of the display area. One of the four subpixels, the white subpixel, is as bright as the monochrome white displayed below, and the brightness of each colored subpixel does not exceed one-third of the monochrome white. The total white brightness of the entire display cannot exceed half the brightness of the white subpixel (the white area of ​​the display is created by displaying one white subpixel out of every four subpixels, plus the fact that the colored form of each colored subpixel is equivalent to one-third of the white subpixel, so the combined three colored subpixels contribute no more than one white subpixel). By switching colored pixels to black, area sharing reduces the brightness and saturation of the color. Area sharing is particularly problematic when mixing yellow, because yellow is brighter than any other color of equal brightness, and saturated yellow is almost as bright as white. Switching the blue pixel (one-quarter of the display area) to black makes yellow too dark.

[0031] U.S. Patents 8,576,476 and 8,797,634 describe a multicolor electrophoretic display having a single backplate including independently addressable pixel electrodes and a common transparent front electrode. Multiple electrophoretic layers are disposed between the backplate and the front electrode. The displays described in these applications are capable of rendering any primary color (red, green, blue, cyan, magenta, yellow, white, and black) at any pixel location. However, using multiple electrophoretic layers located between a single set of addressable electrodes has disadvantages. The electric field experienced by particles in a particular layer is lower than that of a single electrophoretic layer addressed with the same voltage. Furthermore, optical losses in the electrophoretic layer closest to the viewing surface (e.g., caused by light scattering or unwanted absorption) can affect the appearance of the image formed in the underlying electrophoretic layer.

[0032] Attempts have been made to provide full-color electrophoretic displays using a single electrophoretic layer. For example, U.S. Patent No. 8,917,439 describes a color display comprising an electrophoretic fluid containing one or two types of pigment particles dispersed in a transparent, colorless or colored solvent, the electrophoretic fluid being disposed between a common electrode and a plurality of pixel electrodes or driving electrodes. The driving electrodes are arranged to expose a background layer. U.S. Patent No. 9,116,412 describes a method for driving a display unit filled with an electrophoretic fluid containing two types of charged particles carrying opposite charge polarities and two contrasting colors. The two types of pigment particles are dispersed in a colored solvent, or in a solvent in which uncharged or slightly charged colored particles are dispersed. The method includes driving the display unit to display the color of the solvent or the color of the uncharged or slightly charged colored particles by applying a driving voltage of about 1% to about 20% of the full driving voltage. U.S. Patents Nos. 8,717,664 and 8,964,282 describe an electrophoretic fluid and a method for driving an electrophoretic display therewith. The fluid contains type I, type II, and type III pigment particles, all of which are dispersed in a solvent or solvent mixture. Type I and type II pigment particles carry opposite charge polarities, and type III pigment particles have a charge level approximately 50% lower than that of type I or type II pigment particles. These three types of pigment particles have different levels of threshold voltage, or different levels of mobility, or both.

[0033] U.S. Patent Nos. 10,475,399 and 10,678,111 describe electrophoretic displays capable of displaying any color at any pixel location. A '399 patent describes a display in which a white (light-scattering) pigment moves in a first direction when addressed with a low applied voltage and in the opposite direction when addressed with a higher voltage. A '111 patent describes a full-color electrophoretic display with four pigments: white, cyan, magenta, and yellow, two of which are positively charged and two are negatively charged. U.S. Patent Publication No. 2022 / 0082896 describes a full-color electrophoretic display with four pigments: white, cyan, magenta, and yellow, three of which are positively charged and the white pigment is negatively charged. Such embodiments of the invention are referred to as CMYW embodiments.

[0034] In addition, there are multi-particle display designs in which colored pigments scatter light (i.e., reflective colored particles). U.S. Patent No. 10,339,876 describes this type of display, which has particles capable of displaying three states: black, white, and red. Similar display designs containing four pigments can display four different colors, see, for example, U.S. Patent No. 9,922,603; or, by using translucent colored particles, such displays can display six colors, see, for example, U.S. Patent No. 11,640,803. Many multi-particle display designs using light-scattering particles include lengthy and “flickering” updates, which can be unappealing to some viewers. The solutions described below can be used to reduce the “flickering” of updates in such displays and, in some instances, to shorten the time required for updates. Summary of the Invention

[0035] This document discloses an improved driving method for a full-color electrophoretic display and a full-color electrophoretic display using these driving methods. In one aspect, the invention relates to an electrophoretic display comprising a transparent electrode, an active matrix backplane including a plurality of pixel electrodes, each pixel electrode coupled to a thin-film transistor including gate lines and source lines, and each pixel electrode coupled to a storage capacitor; and an electrophoretic medium disposed between the transparent electrode and the active matrix backplane, wherein the electrophoretic medium comprises at least three different types of charged pigment particles. The electrophoretic display also includes a controller coupled to a plurality of gate lines and a plurality of source lines of the plurality of pixel electrodes, the controller being configured to address the pixel electrodes in a row-by-row manner. The controller is configured to update an image on an electrophoretic display by performing the following steps: addressing a first row of pixel electrodes by providing a first gate voltage at a first time; addressing a second row of pixel electrodes by providing a second gate voltage at a second time; addressing a first row of pixel electrodes by providing a third gate voltage at a third time; addressing a second row of pixel electrodes by providing a fourth gate voltage at a fourth time; and addressing a first row of pixel electrodes by providing a fifth gate voltage at a fifth time, wherein the first, second, third, fourth, and fifth times are all different, and the time interval between the first and third times is shorter than the time interval between the third and fifth times.

[0036] In one embodiment, the time interval between the third and fifth times is at least twice the time interval between the first and third times. In one embodiment, the time interval between the first and third times is less than 20 milliseconds, optionally less than 10 milliseconds, and optionally approximately 8 milliseconds. In one embodiment, the controller simultaneously provides a first source voltage to the pixels of the first row of pixel electrodes at the first time and a second source voltage to the pixels of the first row of pixel electrodes at the third time, and the polarity of the first source voltage is opposite to that of the second source voltage. In one embodiment, the amplitude of the first source voltage is different from the amplitude of the second source voltage. In one embodiment, the amplitudes of the first and second source voltages are between -15V and +15V, or between -24V and +24V. In one embodiment, the controller simultaneously provides a third source voltage to the pixels of the first row of pixel electrodes at the fifth time. In one embodiment, the first and third source voltages have the same polarity and amplitude. In one embodiment, when the controller updates the image, the electrophoretic medium portions above the pixel electrodes in the first row of pixel electrodes and the electrophoretic medium portions above the pixel electrodes in the second row of pixel electrodes undergo the same color transition. In one embodiment, the controller performs the following additional steps: addressing the third row of pixel electrodes by providing a sixth gate voltage at a sixth time; and addressing the third row of pixel electrodes by providing a seventh gate voltage at a seventh time, wherein the first, second, third, fourth, fifth, sixth, and seventh times are all different, and the time interval between the first and third times is the same as the time interval between the sixth and seventh times. In one embodiment, there are n rows of pixel electrodes in the active matrix backplane, and the first and second rows of pixel electrodes are spaced n / 2 rows apart. In one embodiment, the controller provides at least two separate gate voltages to each thin-film transistor of the active matrix backplane between the first and fifth times. In one embodiment, the electrophoretic medium comprises reflective white particles and at least one subtractive particle, or reflective white particles and at least one reflective color particle. In one embodiment, the electrophoretic medium comprises a fourth type of electrophoretic particles. In one embodiment, two types of particles are negatively charged and two types of particles are positively charged, or one type of particles is negatively charged and three types of particles are positively charged, or three types of particles are negatively charged and one type of particle is positively charged. In one embodiment, the electrophoretic medium is encapsulated in a microcapsule or microcell. Attached Figure Description

[0037] Figure 1A This is a typical cross-sectional view of a four-particle electrophoretic display, in which the electrophoretic medium is encapsulated in a capsule. Figure 1A The structure can be used in multi-particle electrophoretic media containing both reflective pigment particles and subtractive pigment particles.

[0038] Figure 1B This is a typical cross-sectional view of a four-particle electrophoretic display, in which the electrophoretic medium is encapsulated in microcells. Figure 1B The structure can be used in multi-particle electrophoretic media containing both reflective pigment particles and subtractive pigment particles.

[0039] Figure 2 An exemplary equivalent circuit for a single pixel of an electrophoretic display using an active matrix backplane with pixel electrodes coupled to a storage capacitor is shown.

[0040] Figure 3 This is a schematic diagram of an exemplary driving system for controlling the voltage supplied to the pixel electrodes in an active matrix device. The resulting driving voltage can be used to set the optical state of a multi-particle electrophoretic medium.

[0041] Figure 4 An exemplary electrophoretic display including a display module is shown. The electrophoretic display also includes a processor, memory, one or more power supplies, and a controller. The electrophoretic display may also include sensors to allow it to adjust operating parameters based on ambient conditions such as temperature and light.

[0042] Figure 5 The preferred positions of each of the four groups of particles that produce eight standard colors in a white-cyan-magenta-yellow (WCMY) four-particle electrophoretic display are shown, where the white particles are reflective, while the cyan, magenta, and yellow particles are absorptive.

[0043] Figure 6A An exemplary push-pull drive scheme is shown for addressing an electrophoretic medium comprising three subtractive (cyan, yellow, and magenta) particles and one scattering (white) particle.

[0044] Figure 6B An exemplary push-pull drive scheme is shown for addressing an electrophoretic medium comprising an absorbing (black) particle, two reflective (red and yellow) particles, and a scattering (white) particle.

[0045] Figure 7 The diagram depicts a "typical" drive waveform delivered to the pixel electrodes during a single update from the first color to the second color. Notably, this waveform includes repetitive push-pull voltages.

[0046] Figure 8A The color transients produced when an electrophoretic display containing white reflective particles and subtractive particles of cyan, yellow, and magenta are addressed by a repetitive dipole with a first 5ms pulse of +24V and a second 10ms pulse of -12V are shown (by color filter optical density = analytical density measurement).

[0047] Figure 8B The color transients produced when an electrophoretic display containing white reflective particles and subtractive particles of cyan, yellow, and magenta are addressed by a repeating dipole with a first 5ms pulse of -24V and a second 10ms pulse of +12V are shown (by color filter optical density = analytical density measurement).

[0048] Figure 9 It shows Figure 8A and 8B The smooth change in optical density of the display under a generalized push-pull waveform. Figure 9 It shows that regardless of the duration of each pulse including the dipole, the total length of the transition to a certain limiting ring color (i.e., magenta, green, yellow, or blue) in the system is approximately the same.

[0049] Figure 10 This illustrates the gate voltage (V) delivered to the thin-film transistor coupled to the pixel electrode using the method of the present invention. G ) and source voltage (V S Furthermore, the voltage (V) across the electrophoretic medium is shown. P The voltage across the electrophoretic medium is maintained by a storage capacitor associated with each pixel electrode (see [link]). Figure 2 ).

[0050] Figure 11 This is a general description of the driving method of the present invention, wherein subsequent electrode rows are not driven in a typical row-by-row manner. This driving method results in non-uniform spacing between the three consecutive gate pulses for a single image update. In many instances, each pixel on the backplane receives two gate pulses before any other pixel receives the third gate pulse.

[0051] Figure 12 An embodiment of the low-flicker update scheme of the present invention is described.

[0052] Figure 13 An embodiment of the low-flicker update scheme of the present invention is described.

[0053] Figure 14 An embodiment of the low-flicker update scheme of the present invention is described.

[0054] Figure 15 Provided Figure 14 More details on the driving scheme described in [the document].

[0055] Figure 16A The prior art line-by-line drive is described, which is used with Figure 16B The embodiments of the present invention described herein form a comparison.

[0056] Figure 16B Provided Figure 14 More details on the driving scheme described in [the document]. Detailed Implementation

[0057] This invention includes an electrophoretic display with a multi-particle electrophoretic medium, and an improved method for driving such a medium. The display of this invention typically includes an active matrix backplane of pixel electrodes controlled by thin-film transistors, wherein each pixel electrode is also coupled to a storage capacitor. While the driving method of the display can be generalized to any electrophoretic display using a push-pull waveform, the display of this invention is more suitable for driving more complex electrophoretic media, such as those requiring precise simultaneous control of three, four, or more particles. Its advantage is that displays using the disclosed driving scheme generally appear less "flickering" compared to addressing with conventional line-by-line constant frame spacing updates (which has been state-of-the-art for decades). Such displays may contain multiple subtractive colored electrophoretic particles and / or multiple reflective colored electrophoretic particles. In a preferred embodiment, the electrophoretic medium includes white particles and subtractive primary color particles of cyan, yellow, and magenta, i.e., the WCMY system.

[0058] Methods for fabricating electrophoretic displays containing four (or more) particles have been discussed in the prior art. The electrophoretic fluid can be encapsulated in microcapsules or integrated into a microcell structure, then sealed with a polymer layer. The microcapsules or microcell layer can be coated or laminated onto a plastic substrate or film with a transparent coating of a conductive material. Alternatively, microcapsules can be coated onto a transparent substrate or other electrode material using a spraying technique. (See U.S. Patent No. 9,835,925, which is incorporated herein by reference). The resulting component can be laminated to a backplane with pixel electrodes using a conductive adhesive. Alternatively, the component can be attached to one or more segmented electrodes on the backplane, wherein the segmented electrodes are directly driven.

[0059] This invention provides an architecture and method for addressing an electrophoretic display with dipoles using a thin-film transistor array. In a first embodiment, both pulses of the dipole are provided at the display's (conventional) frame rate, unlike prior art methods that require each pulse in the dipole to have a duration of at least one frame. In this embodiment of the invention, the total length of the dipole is equal to the duration of a conventional frame. In a second embodiment, the rows of the display are divided into two groups, each scanned twice to complete a full update frame. The first embodiment of the display allows for flexible selection of the length ratio of the "push" and "pull" pulses in the dipole, while in the second embodiment, the ratio of the "push" and "pull" durations is 3:1. The electrophoretic composition provided by this invention allows for addressing of the display, thereby producing color images without visible flicker or flare.

[0060] The electrophoretic medium used herein includes charged particles that vary in color, reflection or absorption properties, charge density, and mobility in an electric field (measured in zeta potential). Particles that absorb, scatter, or reflect light over a wide wavelength range or at selected wavelengths are referred to herein as colored particles or pigment particles. In addition to pigments (strictly speaking, this term refers to insoluble colored materials), various materials that absorb or reflect light, such as dyes, photonic crystals, quantum dots, etc., can also be used in the electrophoretic medium and display of this invention. For example, the electrophoretic medium may include a fluid, a plurality of first particles and a plurality of second particles dispersed in the fluid, and a plurality of third particles and a plurality of fourth particles dispersed in the fluid, wherein the first and second particles carry charges of opposite polarities, the first particle is a light-scattering particle, the second particle has one of the subtractive primary colors, the third and fourth particles carry charges of opposite polarities, and each of the third and fourth particles has a subtractive primary color different from and different from that of the second particle, wherein the electric field required to separate clusters formed by the third and fourth particles is greater than the electric field required to separate clusters formed by any other two types of particles.

[0061] The electrophoretic medium of the present invention may contain any additives used in prior art electrophoretic media, such as those described in the aforementioned patents and applications of Einker and MIT. Thus, for example, the electrophoretic medium of the present invention typically contains at least one charge control agent to control the charge on various particles, and polymers with a number average molecular weight exceeding about 20,000 and substantially non-absorbable to particles may be dissolved or dispersed in the fluid to improve the bistable nature of the display, as described in the aforementioned U.S. Patent No. 7,170,670.

[0062] In one embodiment, the present invention uses light-scattering particles (typically white) and three types of particles that are essentially non-scattering light. Of course, there are no particles that completely scatter light or completely do not scatter light, and the minimum light scattering level of the light-scattering particles used in the electrophoresis of the present invention, as well as the maximum tolerable light scattering level of the essentially non-scattering particles, may vary depending on a variety of factors, such as the exact pigments used, their colors, and the user's or application's tolerance for deviations from the ideal color. The scattering and absorption properties of the pigment can be evaluated by measuring the diffuse reflectance of a pigment sample dispersed in a suitable matrix or liquid against white and dark backgrounds. Such measurements can be interpreted according to a variety of models known in the art, such as one-dimensional Kubelka-Munk processing. In the present invention, preferably, the white pigment, when measured at 550 nm against a black background, exhibits a diffuse reflectance of at least 5% when the white pigment is approximately isotropically distributed in a 1 µm thick layer consisting of the pigment and a liquid with a refractive index less than 1.55 at a volume ratio of 15%. Under the same conditions, yellow, magenta, and cyan pigments preferably exhibit diffuse reflectance of less than 2.5% when measured against a black background at 650, 650, and 450 nm, respectively. (The wavelengths selected above for measuring yellow, magenta, and cyan pigments correspond to the spectral regions where these pigments have minimal absorption.) Colored pigments that meet these criteria are referred to below as “no scattering” or “virtually no light scattering.” Specific examples of suitable particles are disclosed in U.S. Patent No. 9,921,451, which is incorporated herein by reference.

[0063] Alternative particle groups may also be used, including four groups of reflective particles, or a combination of one absorbing particle with three or four different groups of reflective particles, such as those described in U.S. Patents 9,922,603 ​​and 1,003,2419, which are incorporated herein by reference. For example, white particles may be formed from inorganic pigments such as TiO2, ZrO2, ZnO, Al2O3, Sb2O3, BaSO4, PbSO4, etc., while black particles may be formed from CI pigments such as Black 26 or 28 (e.g., manganese ferrite black spinel or copper chromite black spinel) or carbon black. The colors of the third / fourth / fifth type particles may be such as red, green, blue, magenta, cyan, or yellow. Pigments for such particles include, but are not limited to, CI pigments PR 254, PR122, PR149, PG36, PG58, PG7, PB28, PB15:3, PY138, PY150, PY155, or PY20. Specific examples include Clariant's Hostaperm Red D3G 70-EDS, Hostaperm Pink E-EDS, PV Fast Red D3G, Hostaperm Red D3G 70, Hostaperm Blue B2G-EDS, Hostaperm Yellow H4G-EDS, and Hostaperm Green GNX; BASF's Irgazine Red L 3630, Cinquasia Red L 4100 HD, and Irgazin Red L3660 HD; and Sun Chemical's Phthalocyanine Blue, Phthalocyanine Green, Diarylazo Yellow, or Diarylazo AAOT Yellow.

[0064] like Figure 1A and Figure 1BAs shown, electrophoretic displays (101, 102) typically include a top transparent electrode 110, an electrophoretic medium 120, and a bottom electrode 130, the bottom electrode 130 typically being a pixel electrode of a pixel active matrix controlled by a thin-film transistor (TFT). The electrophoretic medium 120 described herein contains four different types of particles 121, 122, 123, and 124; however, the methods and displays described herein can use more (or fewer) particle groups. For example, the technique of the present invention can be used with a set of three types of particles, such as white, black, and red, wherein one of the three different types of particles has a lower charge than the other two types. In some instances, two particles are positively charged, and one (or both) of the particles are negatively charged. In some instances, one particle is positively charged, and three particles are negatively charged. In some instances, one particle is negatively charged, and three particles are positively charged. The electrophoretic medium 120 is typically separated by the walls of microcapsules 126 or microunits 127. An optional adhesive layer 140 can be disposed near any layer; however, it is typically disposed near the electrode layers (110 or 130). A given electrophoretic display (105, 106) may have more than one adhesive layer 140; however, a single layer is more common. The entire display stack is typically disposed on a substrate 150, which may be rigid or flexible. The displays (101, 102) typically also include a protective layer 160, which may simply protect the top electrode 110 from damage, or it may enclose the entire display (101, 102) to prevent water ingress, etc. The electrophoretic displays (101, 102) may also include a sealing layer 180 if desired. In some embodiments, the adhesive layer 140 may include a primer component to improve adhesion to the electrode layer 110, or a separate primer layer may be used ( Figure 1B (Not shown in the image). The structure and components of the electrophoretic display, pigments, binders, electrode materials, etc., are described in several patents and patent applications published by Einkel, such as US 6922276, 7002728, 7072095, 7116318, 7715088; and 7839564, all of which are incorporated herein by reference in their entirety.

[0065] In some embodiments, such as Figure 1A As shown, an electrophoretic display may include transparent electrodes, an electrophoretic medium, and multiple back pixel electrodes. To produce a high-resolution display (e.g., for displaying images), each pixel electrode 130 can be individually addressed and is unaffected by interference from adjacent pixels, thereby accurately reproducing the image file on the display. One way to achieve this is to provide an array of nonlinear elements (such as transistors or diodes), with at least one nonlinear element associated with each pixel, to produce an "active matrix" display. (See also...) Figure 2The addressing electrode or pixel electrode 130 that addresses a pixel is connected to a suitable voltage source via an associated nonlinear element. Typically, when the nonlinear element is a transistor, the pixel electrode is connected to the drain of the transistor; this arrangement will be assumed in the following description, although this arrangement is inherently arbitrary and the pixel electrode may also be connected to the source of the transistor.

[0066] Traditionally, in high-resolution arrays, pixels are arranged in a two-dimensional array of rows and columns, such that any particular pixel is uniquely identified by the intersection of a specified row and a specified column. (See also...) Figure 3 In each column, the sources of all transistors are connected to a single column electrode, while the gates of all transistors in each row are connected to a single row electrode. Similarly, the source-to-row and gate-to-column assignments are conventional but essentially arbitrary and can be reversed if needed. Row electrodes are typically connected to row drivers (gate drivers, gate controllers), which essentially ensure that only one row is selected at any given time by applying a selected voltage to the selected row electrode, for example, to ensure that all transistors in the selected row are turned on, while non-selected voltages are applied to all other rows, for example, to ensure that all transistors in these non-selected rows remain off. Column electrodes are typically connected to column drivers (source drivers, source controllers), which apply selected voltages to the individual column electrodes to drive the pixels in the selected row to their desired optical state. (These voltages are relative to a common front electrode, which is typically located on the side of the electro-optical medium opposite the nonlinear array and extends across the entire display.) After a pre-selected interval (called the "row addressing time"), the selected row is deselected, the next row is selected, and the voltage on the column driver is changed to write the next row to the display. This process is repeated to write the data line by line across the entire display. The time between consecutive updates of a specific line in the display is called a "frame." Therefore, the frame length for a display updating at 60Hz is 16 milliseconds. Electrophoretic displays can use various frame times, such as 8-millisecond frames, 12-millisecond frames, 5-millisecond frames, etc. In some instances, frames are longer than 1 millisecond but shorter than 30 milliseconds.

[0067] It is important to note that the voltage amplitude available in this row-column drive may be limited by the materials used to manufacture the nonlinear elements, such as thin-film transistors. In many embodiments, the semiconductor material is silicon, particularly amorphous silicon, which can control drive voltages on the order of ±15 V. In other embodiments, the semiconductor of the thin-film transistor can be a metal oxide, such as indium gallium zinc oxide (IGZO), which allows for a wider range of drive voltages, such as up to ±30 V, as described in U.S. Patent Publication No. US2022 / 0084473. This design feature is particularly critical when sorting pigments in multi-particle systems using drive waveforms. In such systems, it is beneficial to provide at least five voltage levels (high positive, low positive, zero, low negative, high negative), and the higher the total voltage, the easier it is to separate particles. For more details, see U.S. Patent Publication No. 2021-0132459.

[0068] In the attached diagram Figure 2 An exemplary equivalent circuit for a single pixel of an electrophoretic display is depicted. As shown, the circuit includes a storage capacitor 10 formed at the pixel electrode. Figure 1A and 1B Between element 130 and the capacitor electrode. Electrophoretic dielectric 20 is represented as a capacitor and resistor connected in parallel. In some instances, the direct or indirect coupling capacitance 30 (often referred to as "parasitic capacitance") between the gate electrode of the transistor associated with a pixel and the pixel electrode can introduce unwanted noise into the display. Typically, parasitic capacitance 30 is much smaller than the capacitance of storage capacitor 10, and when a pixel row of the display is selected or deselected, parasitic capacitance 30 can generate a small negative offset voltage, also known as "recoil voltage," on the pixel electrode, which is typically less than 2 volts. [In some embodiments, to compensate for the unwanted "recoil voltage," a common potential V can be provided to the capacitor electrode and the top plane electrode associated with each pixel.] com Thus, when V com Set to equal to the recoil voltage (V) KB When the value is set to ), each voltage supplied to the display can be offset by the same amount, and no net DC imbalance will occur.

[0069] In conventional electrophoretic displays using active matrix backplanes, each pixel electrode has an associated capacitor electrode (storage capacitor), such that the pixel electrode and the capacitor electrode form a capacitance; see, for example, International Patent Application WO01 / 07961. In some embodiments, an N-type semiconductor (e.g., amorphous silicon) can be used to form a transistor, and the “selected” voltage and “non-selected” voltage applied to the gate electrode can be positive and negative, respectively.

[0070] Figure 3Further details of row-column addressing used in an "active matrix" display are shown. Addressing electrodes, or pixel electrodes, for addressing a pixel are fabricated on substrate 402 and connected to suitable voltage sources 404 and 406 via associated nonlinear elements. It will be understood that voltage sources 404 and 406 can originate from separate circuit elements or be supplied with voltage via a single power supply and power management integrated circuit (PMIC). In some instances, an intermediate source controller 420 is used to control the supply voltage; however, in other embodiments, controller 460 is configured to control the entire addressing process, including coordinating the gate and source lines. It should also be understood that... Figure 3 This is a diagram of the layout of the active matrix backplane 400, but in reality, the active matrix has depth, and some components (such as TFTs) can actually be located below the pixel electrodes, while vias provide electrical connections from the drain to the pixel electrodes above.

[0071] Traditionally, in high-resolution arrays, pixels are arranged in a two-dimensional array of rows and columns, such that any particular pixel is uniquely defined by the intersection of a designated row and a designated column. The sources of all transistors in each column are connected to a single column (scan) line 406, while the gates of all transistors in each row are connected to a single row (gate) line 408; similarly, the source-to-row and gate-to-column assignments are conventional but essentially arbitrary and can be reversed if necessary. Gate lines 408 are optionally connected to a gate controller 430, which essentially ensures that only one row is selected at any given time, i.e., a selected voltage is applied to the selected row electrode to ensure that all transistors in the selected row are turned on, while non-selected voltages are applied to all other rows to ensure that all transistors in these non-selected rows remain off. Column scan lines 406 are optionally connected to a source controller 420, which applies selected voltages to each scan line 406 to drive the pixels in the selected row to their desired optical state. (The voltages mentioned above are relative to a common top electrode.) Figure 3 (Not shown in the image.) In a conventional driver, after a preselection interval called "row addressing time," the selected row is deselected, the next row is selected, and the voltage on the column driver is changed to write the next row of the display. In a "typical" backplane driver, this process is repeated linearly to write the entire display row by row. Figure 3 As shown, the time interval between gate voltage pulses in each frame is typically constant and represents the rhythm of line-by-line addressing. It is worth noting that this invention does not achieve a uniform interval between gate voltage pulses for a given addressing line of a pixel electrode.

[0072] Combination Figure 3 The described active matrix backplane is coupled to an electro-optic medium (e.g., as... Figure 1A and 1B(as shown), and is typically sealed to create display module 55, such as Figure 4 As shown. Such a display module 55 forms the core of the electrophoretic display 40. The electrophoretic display 40 typically includes a processor 50, which is configured to coordinate various functions related to displaying content on the display module 55 and convert "standard" images (e.g., sRGB images) into color schemes that best reproduce the images on the display module 55. Of course, if the electrophoretic display is used as a sensor or counter, the content can be correlated with other inputs. The processor is typically a mobile processor chip, such as those manufactured by Freescale or Qualcomm, but other manufacturers are also known. The processor communicates frequently with a non-transitory memory 70, retrieving image files and / or lookup tables from it to perform the color image conversions described below. The non-transitory memory 70 may also contain gate drive instructions so that a particular color transition may require a different gate drive mode. The electrophoretic display 40 may have multiple non-transitory memory chips. The non-transitory memory 70 may be flash memory. Once the desired image has been converted for display on the display module 55, specific image instructions are sent to a controller 60, which helps to send voltage sequences to the corresponding thin-film transistors (as described above). Such voltages typically originate from one or more power supplies 80, which may include, for example, a power management integrated circuit (PMIC). The electrophoretic display 40 may also include a communication unit 85, which may be, for example, a Wi-Fi protocol or Bluetooth, and allows the electrophoretic display 40 to receive images and instructions, which may also be stored in memory 70. The electrophoretic display 40 may also include one or more sensors 90, which may include temperature sensors and / or light sensors, and such information may be supplied to the processor 50 to allow the processor to select the optimal lookup table when the lookup table is indexed for ambient temperature or incident illumination intensity or spectrum. In some instances, multiple components of the electrophoretic display 40 may be embedded in a single integrated circuit. For example, an application-specific integrated circuit (ASIC) may implement the functions of the processor 50 and the controller 60.

[0073] like Figure 5 As shown, advanced color electronic paper electrophoretic synthesis (ACEP) (e.g., containing WCMY particle systems) works largely similarly to printing on bright white paper, because the viewer can only see the colored pigments located on the viewing side of the white pigment (i.e., the only pigment that scatters light). Figure 5 In this scenario, assume the viewing surface of the monitor is located at the top (as shown in the figure), meaning the user views the monitor from this direction, and the illumination light also enters from this direction. Figure 5 In this scenario, assume the light-scattering particles are white pigments. These white light-scattering particles form a white reflector, and any particles above the white particles (such as...) reflect the light. Figure 5(As shown) are all viewed relative to the reflector. A portion of the incident light passes through the subtractive particles, is reflected from the white particles below them, returns through these particles, and exits the display. Different portions of the incident light are absorbed by the subtractive particles. Therefore, the particles above the white particles can absorb various colors, and the colors presented to the user are produced by the combination of the particles above the white particles. Any particles located below the white particles (located behind from the user's perspective) are blocked by the white particles and do not affect the displayed colors. Since the second, third, and fourth particles are essentially non-scattering light, their order or arrangement relative to each other is not important, but for the reasons mentioned above, their order or arrangement relative to the white (light-scattering) particles is crucial.

[0074] More specifically, when cyan, magenta, and yellow particles are located below white particles ( Figure 5 In case [A], there are no particles above the white particle, and the pixel simply displays white. When a single particle is above a white particle, the color of that single particle is displayed. Figure 5 In the cases [B], [D], and [F], yellow, magenta, and cyan are displayed, respectively. When two particles are above a white particle, the displayed color is a combination of the colors of those two particles; in... Figure 5 In case [C], magenta and yellow particles appear red; in case [E], cyan and magenta particles appear blue; and in case [G], yellow and cyan particles appear green. Finally, when all three colored particles are above the white particle ( Figure 5 In the case of [H], all incident light is absorbed by the three subtractive primary color particles, and the pixel displays black.

[0075] It is possible for particles that scatter light to represent a subtractive primary color, thus the display would include two types of light-scattering particles, one white and one colored. In this case, however, the position of the light-scattering colored particles relative to other colored particles covering the white particles will be very important. For example, when the color is represented as black (when all three colored particles are above the white particles), the scattering colored particles cannot be above the non-scattering colored particles (otherwise they would be partially or completely hidden behind the scattering particles, and the color represented would be the color of the scattering colored particles, not black).

[0076] Figure 5An ideal scenario is illustrated where color is uncontaminated (i.e., light-scattering white particles completely cover any particles located behind them). In practice, the coverage of white particles may not be perfect, resulting in some particles that should ideally be completely covered absorbing a small amount of light. This contamination typically reduces the brightness and chromaticity of the resulting color. In the electrophoretic medium of this invention, this color contamination should be minimized to the extent that the resulting color is comparable to industry standards for color reproduction. A particularly popular standard is SNAP (Newspaper Advertising Production Standard), which specifies the values ​​of L*, a*, and b* for the eight primary colors mentioned above. (In the following text, "primary color" will be used to refer to...) Figure 5 The eight colors shown are: black, white, three subtractive primary colors, and three additive primary colors.

[0077] Figure 6A The diagram shows a typical waveform (simplified form) used to drive the aforementioned four-particle WCMY electrophoretic display system. These waveforms have a "push-pull" structure: that is, they consist of dipoles containing two pulses of opposite polarities. Typically, each dipole has a pulse of voltage V1 applied for time t1, followed by a pulse of voltage V2 applied for time t2. The dipole impulses are balanced when V1t1 + V2t2 = 0. The amplitude and length of these pulses determine the resulting color. At least five such voltage levels should be present. Figure 6A The diagram shows high and low voltages, as well as positive and negative voltages, and zero volt. Generally, "low" (L) refers to a range of approximately 5–15V, while "high" (H) refers to a range of approximately 15–30V. Generally, the higher the amplitude of the "high" voltage, the better the color gamut achieved by the display. In some instances, especially where more colors are required, medium voltages are also included. "Medium" (M) levels are typically around 15V; however, the value of M depends to some extent on the composition of the particles and the environment of the electrophoretic medium.

[0078] It is worth noting that, for Figure 6A The dipole waveforms used to provide magenta, yellow, green, and blue dipoles are at least approximately impulse balanced. On the other hand, dipole addressing is not required to generate black and white. Simple monopole pulses in any direction will cause colored and white pigments with opposite charges to move toward or away from the viewing surface, thus the display behaves similarly in this case to a conventional display containing black and white pigments. Furthermore, since these monopole pulses are not DC balanced, additional charge-clearing pulses must be added to the device drive protocol, either at the beginning or end of an image update, or at the end of an extended unbalanced drive sequence (as may happen when scrolling text). However, even if the waveform is impulse balanced overall, dipole addressing can break symmetry. For example, there can be... ,,and See, for example, Dukhin AS and Dukhin SS, “Aperiodic capillary electrophoresis method using an alternating current electric field for separation of macromolecules”, Electrophoresis, June 2005; 26(11): 2149-53. Thus, as long as the pigment mobility depends on the applied electric field, this waveform could lead to overall pigment drift.

[0079] Figure 6B Two typical push-pull waveforms are shown for displaying the color of the less charged particles in a four-particle system on a viewing surface. This four-particle system includes one scattering white particle, one absorbing black particle, and two colored scattering particles (yellow and red). See, for example, U.S. Patent No. 10,339,876. Figure 6B In the described examples, the yellow particles carry a high negative charge, and the white particles carry a low negative charge. The black particles carry a high positive charge, and the red particles carry a low charge and are both positive.

[0080] from Figures 6A-6B As can be seen, in dipoles typically used to produce a specific color, one pulse has a shorter duration than the other. Furthermore, although... Figure 6A and 6B The simplest push-pull waveform (dipole) required to form color is shown, but it is understandable that actual waveforms typically require repeating these patterns multiple times, such as... Figure 7 As shown. Repeating dipoles are a major source of display flicker because the pigment is first driven in one direction and then in the other. If the flicker frequency is too low, the transition from one color to another will appear discordant. Therefore, preferably, the length of any pulse in the dipoles used to address the display of this invention is less than about 17 milliseconds, which corresponds to the threshold of human-perceived flicker (about 60 Hz). Unfortunately, in typical progressive scan, each frame lasts approximately 10-20 milliseconds, and pulses spanning two frames are often visible, and the overall update experience is perceived as “flickering.”

[0081] Nevertheless, when differential pigment mobility is caused by a field effect, it is not necessary to drive the pigments across the entire width of the cavity containing them. This provides the option to switch (at least partially) colors without producing (visually perceptible) flicker. This is, for example, when field-dependent mobility is a polarization effect. In this case, because the pigments are much smaller than the cavity containing them, the pigments polarize much faster than the entire cell. In this case, pigment sorting can be performed at a higher frequency than is required to switch the pigment from one extreme state to another, and thus eliminate visually perceptible flicker.

[0082] In traditional active matrix addressing, the duration of a dipole pulse is no less than the duration of a frame (a frame = the time to address each pixel from one corner to the opposite corner of the active matrix, where each row is addressed sequentially, with each row taking the same amount of time to address, and no row is re-addressed until each row of the display has been addressed only once). Therefore, the longer pulse length of the dipole must be an integer multiple of the frame duration (assuming the display typically addresses at a constant frame rate). If the ratio between longer and shorter pulses in the dipole is r, and the dipole time is required to be shorter than approximately 17 ms (approximately the limit of perceptible flicker), then the display's scan frequency must be higher than 1000 / 17 multiplied by r + 1. For example, if the longer pulse is twice the length of the shorter pulse, then the display's scan frequency must be at least 3000 / 17 = approximately 177 Hz. Higher pulse length ratios require higher frame rates. Unfortunately, at the current level of technology, providing such high frame rates results in high electronic costs and power consumption. Such advanced electronic devices are generally unpopular in consumer electronics because sales of these products are heavily influenced by price.

[0083] Refer again Figure 6A Three different types of color transitions can be identified in the push-pull waveform of the WCMY system. These states are referred to as "railing states," "rail bounce states," and "limiting loop states." The term "rail" used in the field of electrophoretic displays refers to the fact that pigments are moved using an electric field between the two walls of the cavity. When the movement of a pigment is restricted by one of the walls, it is said to be on a rail, and the process of moving it to that position is called "railing." The two railing states of the WCMY system correspond to black (where all three subtractive pigments are on the viewing surface, while the white pigment is on the rail on the other side) and white (where the pigment positions are reversed).

[0084] In the "orbit bounce state," the pigments need to be arranged in one of two orbital states, and then the direction of the electric field is reversed in a relatively short time. The colored pigment with the highest mobility will be the one that moves fastest through the white pigment, and is therefore the pigment modulated during the second pulse. In this invention, the orbit bounce states are red and cyan. Red is achieved by first switching the display to a black orbital state (using a positive pulse), and then using a negative pulse of insufficient length to significantly switch the magenta or yellow pigment to pull back the cyan pigment. Cyan is achieved by reversing the waveform, first providing a white orbital state (where the three colored pigments are in the back orbital), and then using a short positive pulse to bring the cyan pigment to the viewing surface. Since the orbit bounce state requires all three colored pigments to move along the orbits in the first pulse, this pulse cannot be shorter than the time required to move the slowest pigment across the width of the cavity containing the electrophoretic fluid. Therefore, to avoid visible flickering when creating orbit bounce colors, the time required for the slowest pigment to cross the cavity must be less than 17 milliseconds. This is possible in some embodiments of the invention (where the cavity is very narrow), but not in others. In these cases, flickering will occur when accessing the orbital bounce state, which can be handled, for example, by interleaving the updating of pixels in the display.

[0085] The "limiting ring" colors of this invention are magenta and yellow, and their opposite states, green and blue. These colors are obtained through dipole addressing, but unlike the orbital bounce state, the pulse length in the dipole does not need to be long enough for any pigment to pass through the cavity containing the electrophoretic fluid. In fact, the longest pulse in the dipole sequence used to provide the limiting ring colors can be as short as about 2 milliseconds (or even shorter—the apparatus used by the inventors for addressing experimental displays does not allow for shorter pulses). It should be noted that the yellow pigment can carry a relatively weak positive or negative charge and still... Figure 8A-9 It is presented in the manner shown.

[0086] Figure 8A and 8B The optical transients that occur when using a series of suitable dipoles to generate limit ring colors are shown. Figure 8A and 8B Additionally, observations of the motion of multiple subtractive particles with different charges relative to each other were provided. Figure 8A and 8B The optical transients shown are described using "resolution density," an index that decomposes the optical density measured in reflection when the display is addressed into the contribution of each of the cyan, magenta, and yellow pigments. Figure 8AIn the experiment, the display, starting in a white state, was addressed by a series of dipoles consisting of a first pulse of +24V lasting 5ms, followed by a second pulse of -12V lasting 10ms. Between the pulses was a "rest period," during which the display was addressed at 0V for 10ms. These rest periods are not necessary for color formation, but are required for measuring optical density during waveform progression due to limitations in the integrated spectrometer used. It can be seen that, using this impulse-balanced pulse sequence, all three pigments move in phase, but the magenta pigment moves further backward during the high-voltage dipole pulses than during the low-voltage pulses. The cyan pigment moves similarly to the magenta pigment, but with a much larger amplitude, while the yellow pigment is barely visible. Therefore, at the end of this dipole sequence, the display oscillates between a magenta state (when the cyan pigment is backward) and a blue state (when the cyan pigment is forward).

[0087] Figure 8B The result is shown when the waveform polarity is reversed, i.e., the display is addressed by a series of dipoles comprising a first pulse of -24V for 5ms, followed by a second pulse of +12V for 10ms, and then 10ms intervals separated by 10ms pauses. Figure 8A The waveform shown begins at its endpoints. All three colored pigments move in phase again. The magenta pigment recedes further during the high-voltage pulse than it advances during the low-voltage pulse, thus evolving to a position away from the viewing surface. Conversely, the yellow pigment advances further during the low-voltage pulse than it recedes during the high-voltage pulse, thus eventually reaching the viewing surface. The cyan pigment oscillates with a larger amplitude than the other colored pigments. At the end of this dipole sequence, the display oscillates between a yellow state (when the cyan pigment recedes) and a green state (when the cyan pigment advances).

[0088] In the relevant illustrations, Figure 9 The resolved density of three colored pigments is illustrated schematically as it varies in low-pressure and high-pressure dipole sequences at approximately impulse equilibrium. Importantly, as... Figure 9 As shown, regardless of the pulse duration constituting the dipole, the total length of the transition to one of the limiting ring colors (magenta, yellow, green, blue) is approximately the same, for example, in the range of about 1-200 milliseconds per pulse. Therefore, given the limitations of the electronics, it is possible, but not preferred, for the pulses of the limiting ring colors to be as short as possible, for example, shorter than about 17 milliseconds, to avoid visible flickering during the transition. The length ratio of the two pulses in the dipole is preferably in the range of 1:1 to 1:10, with shorter pulses having higher voltages.

[0089] If the higher voltage pulse is positive, the display will oscillate between magenta and cyan. If the higher voltage pulse is negative, the display will oscillate between yellow and green. If the pulse is too short for the cyan pigment to reach its preferred position, a "supplementary" pulse can be provided at the end of the waveform. This pulse's amplitude and duration are adjusted to shift the cyan, but with minimal detrimental effect on the yellow and magenta pigments. It should be noted that the same pulse duration ratio can be used to produce any limiting ring color. Figure 8A-9 Analysis representation is widely used Figure 6B The push-pull waveform, and the techniques described below, can also be successfully used to reduce flicker in multi-particle electrophoresis displays with more than one reflective particle.

[0090] Offset gate pulse drive

[0091] Because the pulse ratio of the limit ring color is constant and insensitive to pulse width, an alternative addressing scheme can be used. This scheme provides a full dipole every two backplane regular frames (regular frame = the time it takes to update each pixel of the active matrix backplane only once per row). This driving method is used in... Figure 6A Or, as shown in 6B, it is impossible to perform conventional line-by-line driving on an active matrix backplane using the push-pull waveform, since the latter requires at least three frames, and often more. Using the alternative drive, shorter single voltage pulses can be used, and these shorter pulses result in less physical movement of the pigments, so the updates do not appear flickering. Therefore, the display can switch between color images with less flicker, which is more pleasant for the viewer. In principle, one pulse of the dipole takes less time than it would take to scan each line in the display using conventional line-by-line addressing (i.e., one frame). The ratio of the two pulse lengths can also be further selected. In some instances, the entire push-pull pulse can be transmitted within a conventional frame time, i.e., the time required to address each pixel in a line-by-line manner from one corner to the opposite corner. Importantly, using the method of the present invention, at least one row of pixel electrodes is updated twice (or more) before each pixel electrode in the active matrix is ​​updated once.

[0092] Figure 10 (Not drawn to scale) An exemplary green push-pull waveform using the driving scheme of the present invention is shown (see [reference]). Figure 6A It is important to understand that... Figure 10 This is merely an example, and this driving method can be used for other colors, as well as subtractive and reflective particle systems. Furthermore, Figure 10The three voltage diagrams in the diagram all represent the voltage provided as a function of time. The spacing between each hash along the x-axis represents the conventional frame time, i.e., the frame time required for conventional progressive drive. This invention is not limited to each dipole spanning only two conventional frames, but such dipoles are more suitable for conventional drive electronics, such as controllers. Similarly, using the method of this invention, it is possible to transmit all pulses of the dipole waveform during a single conventional frame.

[0093] exist Figure 10 In the middle, V G The voltage supplied to a specific gate line of the TFT associated with the pixel electrode is shown. This voltage is ultimately measured by the controller; however, an intermediate gate driver and / or a gate controller can be used (see [link to diagram]). Figure 2 and Figure 3 However, in existing active matrix drives, during image updates, consecutive gate voltages have the same time interval between each gate pulse (see...). Figure 3 In the new driving scheme, the gate voltages are interleaved, and for example, there are different time intervals (Δt G) between the first and second gate pulses and between the second and third gate pulses. This is due to the repetitive nature of the actual drive signal (see...). Figure 7 There are three repeating pulse structures, but the time intervals between these three pulses are not uniform, which is common in existing technology drives.

[0094] Due to the (relatively) fast gate drive time and the storage capacitor associated with the pixel electrode, when the controller provides a suitable scan voltage (V) to the source line associated with the same TFT... S When ), a voltage (V) is provided to both ends of the pixel coupled to the TFT. P As shown in the graph below, the coordinated gate lines and scan lines result in a push-pull waveform that repeats at both ends of the pixel. In some instances, as shown in the V / t graph, the "push" pulse and the "pull" pulse have equal areas, resulting in a DC-balanced waveform. However, these waveforms do not require DC balance, and in many cases, they are not DC-balanced. With this driving scheme, the duration ratio of the push pulse to the pull pulse is 1:3. The push and pull pulses are delivered to a specific row within the time required to update all rows twice. This is impossible with traditional row-column driving that has a consistent gate pulse interval. Because this new push-pull waveform is shorter, it is less "flickering."

[0095] Using conventional row-column driving, the first gate line (i.e., the top of the matrix) is addressed first, then the next row, then the next row, and so on until the nth row, after which it restarts from the first row. Therefore, each row of pixels is addressed by gate pulses at constant intervals. However, in the method of this invention, it is not possible to address every row between the first and second gate pulses of the first row. Therefore, (depending on the shape of the push-pull waveform) only some rows are updated during the time interval between the first and second gate pulses of the first row. For example, as... Figure 11 As shown, the second line receives the gate pulse between the first and second gate pulses of the first gate line; however, subsequent gate lines do not receive the first gate pulse until after the first gate line has received both the first and second gate pulses. Therefore, in at least some embodiments, the rows are divided into two groups (not necessarily consecutive). The first group of rows is updated twice within a first regular frame time, while the second group of rows is updated twice within a second regular frame time. The controller updates the display by providing a first gate voltage (to the first row) at a first time, a second gate voltage (to the second row) at a second time, a third gate voltage (to the first row) at a third time, a fourth gate voltage (to the second row) at a fourth time, and a fifth gate voltage (to the first row) at a fifth time, and so on. The first and second rows do not need to be adjacent; in fact, in many instances, they are not adjacent. The first, second, third, fourth, and fifth times are not the same (i.e., they are not addressed simultaneously), and the time interval between the first and third times is shorter than the time interval between the third and fifth times. In many instances, the time interval between the third and fifth times is less than 17 milliseconds.

[0096] The driving method is as follows Figure 11 As shown, the time interval between the first time and the third time is Δt. G1 The time interval between the third and fifth times is Δt. G1 When the row is divided into two groups, Δt G1 'ratio Δt G1 Three times longer. It should be noted that... Figure 11 This is an example of transmitting a single push-pull waveform to multiple rows of pixels for updating. In other embodiments, Δt G1 'Can be compared to Δt G1 More than three times longer. The second line (including the second and fourth lines) does not need to be directly adjacent to the first line. Furthermore, for the entire display (or at least...) Figure 11 (As shown in the display section), all rows receive the same type of continuously repeating waveform or a push-pull waveform of opposite polarity that updates that section of the display to the colors required for image updates. Nevertheless, Figure 11The technique shown can be used for all other limiting ring colors, but the voltage applied to the source line can be different to achieve different colors. For example, the "push" voltage can be positive or negative, and the amplitude can be high or low, while the "pull" voltage is usually of opposite polarity, but the amplitude is not necessarily the same. Of course, the two voltages can also have the same polarity to produce longer pulses (duration twice the frame time). Using the technique of the present invention, longer pulses can be used in the manner described above to achieve colors of the orbital bounce state (i.e., red and cyan). However, if the drive pulse is too short for the cyan pigment to reach its preferred position, a "supplementary" pulse can be provided at the end of the waveform to move the cyan to the correct position while minimizing the detrimental effects on the yellow and magenta pigments. In addition, the same drive technique can also be used to reduce flicker when updating electrophoretic media containing reflective particles, such as... Figure 6B As shown. In principle, all eight primary colors of the WCMY system can be rendered flicker-free, provided that the longer of the two dipole pulses used to address the track bounce color is shorter than approximately 17 milliseconds. Furthermore, other colors can be provided through dithering. For example, dithering may be preferred if effects such as animation or scrolling are required.

[0097] Figure 12 A first-line scanning scheme using the method of the present invention is illustrated. Each point in the figure represents the activation of a specific line. In this embodiment, instead of scanning every line of the display before starting a new backplane scan, the lines are divided into two groups. The first group of lines is scanned twice, and then the second group of lines is scanned twice. In each double scan, a "push" voltage is first provided by the source driver for the dipoles of each column, followed by a "pull" voltage.

[0098] The ratio of the "push" length to the "pull" length depends on the number of rows to be scanned in the first and second groups. If the proportion of rows scanned in the first scan is f, then the ratio of the "push" length to the "pull" length is f:(2-f). Therefore, if f=½, the ratio of pulse lengths is 0.5:1.5=1:3. If there is a fixed time delay between the end of one scan and the start of the next scan, then simply add a small constant to each number in this ratio.

[0099] Figure 12 A potential challenge with the described scheme lies in the "seam" between the top and bottom of the display, where the phases of the "push" and "pull" portions of the waveform change. This seam is visible in the final image, but is typically invisible during updates due to its high frequency. Figure 13Another approach is shown that achieves a 1:3 push:pull ratio without seams. In this approach, the addressing of each odd-numbered row is repeated twice, and then the addressing of each even-numbered row is also repeated twice. This gives the same push-pull timing effect as dividing the panel into two equal blocks of consecutive rows.

[0100] Figure 14 An additional embodiment of the driving scheme is shown, in which row addressing is interleaved, but in this case, various different push:pull ratios can be freely chosen. Figure 13 and 14 During the scanning process, there are no "seams" between different areas of the display. Figure 14 The driving method is also applicable to updating active matrix display fields, where multiple adjacent pixels change to different colors during image updates.

[0101] exist Figure 15 and 16B More details are shown in the middle. Figure 14 The driving scheme. Figure 15 A planar schematic diagram of the active matrix array of the present invention is shown, the array comprising thin-film transistors whose transconductance is modulated by gate voltage provided by gate lines spanning the backplane along the row direction. Figure 16B This illustrates addressing the (n+m)th row by providing a selected voltage to the gate line of the (n+m)th row using a gate driver, and providing a non-selected voltage to every other row. The appropriate voltage (i.e., the "push" in "push-pull") of the first pulse to be applied to the dipole of the (n+m)th row is provided to the source line by the source driver. For ease of comparison, Figure 16A This illustrates the conventional line-by-line addressing of existing technologies.

[0102] Back Figure 16B After addressing row (n+m), row n is addressed by providing a selected voltage to the gate line of row n and then using the gate driver to provide a non-selected voltage to every other row. The source driver provides the appropriate voltage to the source line for the second pulse (i.e., the "pull" in "push-pull") to be applied to the dipole of row n. Addressing of row (n+m+1) is now performed, and so on. No more than one row is ever selected at any given time. If the total number of rows on the display is r, the ratio of dipole duration is m / (r–(m+a)), where a is a constant that depends on the delay between frames and is typically much smaller than r or m.

[0103] All of the above driving embodiments can be implemented using a single gate driver suitable for providing this capability or a combination of multiple synchronous, more conventional gate drivers. It can be seen that with this design, each row is addressed twice during a regular frame interval, thus the row addressing time is half that of a conventional display, where each row is addressed only once during a single frame. In some prior art TFT designs, a single gate line connects to two rows of pixels and provides more than twice the number of source lines, allowing pixels in both rows to be addressed simultaneously. This design (or other similar designs) can be used to increase the row addressing time. There are some less attractive alternatives to the above TFT addressing methods. For example, an array with two TFTs per pixel could be provided, but this would require doubling the number of gate and source lines, increasing cost and potentially causing more severe resolution limitations due to the need to accommodate the additional lines. Conventional TFT addressing could also be used, but with a different frame duration. In this case, the shorter frame duration would need to be equal to the duration of the shorter dipole pulse, which is unnecessary in this invention, as the entire dipole has the same duration as the frame time. As can be seen, using this design, each row is addressed twice per frame, thus halving the row addressing time compared to conventional displays where each row is addressed only once per frame. In some existing TFT designs, a single gate line connects to two rows of pixels, providing more than twice the number of source lines, allowing pixels in both rows to be addressed simultaneously. This design (or other similar designs) can be used to increase row addressing time.

[0104] This invention allows for flicker-free updates to multi-pixel color displays without addressing the display in a traditional line-by-line manner with extremely short frame times. Several aspects and embodiments of the technology described above are presented. It should be understood that various changes, modifications, and improvements will readily occur to those skilled in the art. Such changes, modifications, and improvements are intended to fall within the spirit and scope of the technology described herein. For example, those skilled in the art will readily conceive of various other methods and / or structures for performing functions and / or obtaining results and / or one or more of the advantages described herein, and each such change and / or modification is considered to fall within the scope of the embodiments described herein. Those skilled in the art will recognize, or be able to determine, many equivalents of the specific embodiments described herein through routine experimentation alone. Therefore, it should be understood that the foregoing embodiments are presented by way of example only, and that inventive embodiments may be practiced in ways other than those specifically described within the scope of the appended claims and their equivalents. Furthermore, any combination of two or more features, systems, articles, materials, kits, and / or methods described herein, provided that these features, systems, articles, materials, kits, and / or methods do not contradict each other, is included within the scope of this disclosure.

Claims

1. An electrophoresis display, comprising: Transparent electrode; An active matrix backplane including multiple pixel electrodes, each pixel electrode being coupled to a thin-film transistor including a gate line and a source line, and each pixel electrode being coupled to a storage capacitor; An electrophoretic medium disposed between the light-transmitting electrode and the active matrix backplate, wherein the electrophoretic medium comprises at least three different types of charged pigment particles; A controller coupled to multiple gate lines of the plurality of pixel electrodes and multiple source lines of the plurality of pixel electrodes, the controller being configured to address the pixel electrodes in a row-by-row manner; The controller is also configured to update the image on the electrophoresis display by performing the following steps: The first row of pixel electrodes is addressed by providing a first gate voltage at the first moment; The second row of pixel electrodes is addressed by providing a second gate voltage at a second time; The first row of pixel electrodes is addressed by providing a third gate voltage at a third time. The second row of pixel electrodes is addressed by providing a fourth gate voltage at a fourth time; and The first row of pixel electrodes is addressed by providing a fifth gate voltage at the fifth time. The first time, the second time, the third time, the fourth time, and the fifth time are all different, and the time interval between the first time and the third time is shorter than the time interval between the third time and the fifth time.

2. The electrophoretic display according to claim 1, wherein, The time interval between the third time and the fifth time is at least twice the time interval between the first time and the third time.

3. The electrophoretic display according to claim 1, wherein, The time interval between the first time and the third time is less than 20 milliseconds, optionally less than 10 milliseconds, and optionally about 6 milliseconds or less.

4. The electrophoretic display according to claim 1, wherein, The controller simultaneously provides a first source voltage to the pixels of the first row of pixel electrodes at the first time and a second source voltage to the pixels of the first row of pixel electrodes at the third time, wherein the polarity of the first source voltage is opposite to that of the second source voltage.

5. The electrophoretic display according to claim 4, wherein, The amplitude of the first source voltage is different from the amplitude of the second source voltage.

6. The electrophoretic display according to claim 4, wherein, The amplitudes of the first source voltage and the second source voltage are between -15V and +15V, or between -24V and +24V.

7. The electrophoretic display according to claim 4, wherein, The controller simultaneously provides a third source voltage to the pixels of the first row of pixel electrodes at the fifth time.

8. The electrophoretic display according to claim 7, wherein, The first source voltage and the third source voltage have the same polarity and amplitude.

9. The electrophoretic display according to claim 1, wherein, When the controller updates the image, the electrophoretic medium portion above the pixel electrode in the first row of pixel electrodes and the electrophoretic medium portion above the pixel electrode in the second row of pixel electrodes undergo the same color change.

10. The electrophoretic display according to claim 1, wherein, The controller performs the following additional steps: The third row of pixel electrodes is addressed by providing a sixth gate voltage at the sixth time; and The third row of pixel electrodes is addressed by providing a seventh gate voltage at the seventh time. Among them, the first time, the second time, the third time, the fourth time, the fifth time, the sixth time, and the seventh time are all different, and the time interval between the first time and the third time is the same as the time interval between the sixth time and the seventh time.

11. The electrophoretic display according to claim 1, wherein, The active matrix backplane has n rows of pixel electrodes, and the first row of pixel electrodes and the second row of pixel electrodes are spaced apart by n / 2 rows of pixel electrodes.

12. The electrophoretic display according to claim 11, wherein, The controller provides at least two separate gate voltages to each thin-film transistor of the active matrix backplane between the first time and the fifth time.

13. The electrophoretic display according to any one of the preceding claims, wherein, The electrophoretic medium comprises reflective white particles and at least one subtractive particle, or reflective white particles and at least one reflective color particle.

14. The electrophoretic display according to any one of the preceding claims, wherein, The electrophoretic medium includes a fourth type of electrophoretic particles.

15. The electrophoretic display according to claim 14, wherein, Two types of particles are negatively charged and two types of particles are positively charged, or one type of particle is negatively charged and three types of particles are positively charged, or three types of particles are negatively charged and one type of particle is positively charged.

16. The electrophoretic display according to any one of the preceding claims, wherein, The electrophoretic medium is encapsulated in microcapsules or microunits.

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