The subject matter disclosed herein relates to means and methods to drive electro-optic displays. More particularly, the subject matter is related to driving methods and/or schemes for reducing optical kickback and build-up of remnant voltages caused by residual charges.
Electrophoretic displays or EPDs are commonly driven by so-called DC-balanced waveforms. DC-balanced waveforms have been proven to improve long-term usage of EPDs by reducing severe hardware degradations and eliminating other reliability issues. However, the DC-balance waveform constraint limits the set of possible waveforms that are available to drive the EPD display, making it difficult or sometimes impossible to implement advantageous features via a waveform mode. For example, when implementing a “flash-less” white-on-black display mode, excessive white edge accumulation may become visible when gray-tones that have transitioned to black are next to a non-flashing black background. To clear such edges, a DC-imbalanced drive scheme may have worked well, but such drive scheme requires breaking the DC-balance constraint. Waveforms that are not DC-balanced may result in polarization kickback (e.g., a change in the optical state of an electro-optic medium in a short period after the medium ceases to be driven; for example, a pixel driven to black play revert to a dark gray a short period after the waveform concludes) and cause damage to the electrodes.
Furthermore, electro-optic displays driven by DC-imbalanced waveforms may produce a remnant voltage, this remnant voltage being ascertainable by measuring the open-circuit electrochemical potential of a display pixel. It has been found that remnant voltage is a more general phenomenon in electrophoretic and other impulse-driven electro-optic displays, both in cause(s) and effect(s). It has also been found that DC imbalances may cause long-term lifetime degradation of some electrophoretic displays.
There exists a need to design driving methods or schemes that address the deficiencies described above. In particular, there exists a need for driving methods or schemes that can eliminate or minimize the hardware degradations caused by optical kickback and remnant voltage.
In one aspect, the invention includes a method for driving an electro-optic display having a plurality of display pixels where each of the display pixels is associated with a display transistor. The method includes the following steps in order: A first voltage is applied to a first display transistor associated with a first display pixel of the plurality of display pixels. The first voltage is applied during at least one frame of a driving waveform. A second voltage is applied to the first display transistor associated with the first display pixel. The second voltage has a non-zero amplitude less than the first voltage and is applied during the last frame of the driving waveform. The amplitude of the second voltage is based on a voltage offset value and a sum of remnant voltages each frame of the driving waveform contributes to the first display pixel when the first voltage is applied to the first display transistor associated with the first display pixel.
In some embodiments, the duration of each frame of the driving waveform is substantially the same. In some embodiments, the amplitude of the second voltage is further based on an amount of lightness of the first display pixel resulting from the driving waveform. In some embodiments, the voltage offset value is based on a voltage contributed to the first display pixel due to a change in a gate voltage of the first display transistor and a parasitic capacitance of the first display transistor.
In some embodiments, the method also includes applying a third voltage to the first display transistor associated with the first display pixel, wherein the third voltage is substantially 0V.
In some embodiments, an amount of remnant voltage each frame of the driving waveform contributes to the first display pixel when the first voltage is applied to the first display transistor associated with the first display pixel is determined based on the amplitude of the first voltage and a remnant voltage coefficient corresponding to an amount of remnant voltage a frame of the driving waveform contributes to the display pixel.
In some embodiments, the method also includes determining the remnant voltage coefficients using an operational transconductance amplifier circuit model.
In another aspect, the invention includes a method for driving a black-and-white electro-optic display to an optical rail state. The electro-optic display includes an electrophoretic display medium electrically coupled between a plurality of display pixel electrodes and a common electrode. Each of the plurality of display pixel electrodes is associated with a display pixel, and the electrophoretic display medium includes a plurality of electrically charged black pigment particles and electrically charged white pigment particles. The method includes the following steps in order: A first display transistor associated with a first display pixel of the plurality of display pixels is connected to a first voltage driver circuit configured to provide a first voltage sufficient to drive the display pixel to an optical rail state. The first voltage is provided during one or more frames of a driving waveform. The first display transistor associated with the first display pixel of the plurality of display pixels is connected to a second voltage driver circuit configured to provide second voltage having a non-zero amplitude less than the first voltage for reducing an amount of remnant voltage the driving waveform contributes to the first display pixel, wherein the second voltage is provided after the one or more frames of the driving waveform. The first display pixel is placed in a floating state.
In some embodiments, the optical rail state comprises one of a substantially black state or a substantially white state. In some embodiments, the electrophoretic display medium includes only the plurality of electrically charged black pigment particles and electrically charged white pigment particles.
In some embodiments, the second voltage is provided for a period of time longer in duration than each frame of the driving waveform. In some embodiments, the second voltage is provided for a period of time shorter in duration than each frame of the driving waveform.
In some embodiments, connecting the first display transistor associated with the first display pixel of the plurality of display pixels to a first voltage driver circuit includes setting a first switching device in electrical communication with the first voltage driver circuit and a display pixel electrode associated with the first display pixel to a closed state.
In some embodiments, connecting the first display transistor associated with the first display pixel of the plurality of display pixels to the second voltage driver circuit includes setting the first switching device to an open state, and setting a second switching device in electrical communication with the second voltage driver circuit and a display pixel electrode associated with the first display pixel to a closed state.
In some embodiments, placing the first display pixel in a floating state comprises setting the second switching device to an open state. In some embodiments, placing the first display pixel in a floating state includes disconnecting an electrical connection between the common electrode and a ground voltage.
In some embodiments, the first voltage and the second voltage have the same polarity. In some embodiments, the amplitude of the second voltage and a duration of time the second voltage is provided are based on an amount of lightness of the optical rail state resulting from the driving waveform.
The subject matter disclosed herein relates to improving electro-optic display durability. Specifically, it is related to driving methods or schemes designed to minimize remnant voltages or charges, which can cause hardware degradation over time.
The term “electro-optic”, as applied to a material or a display, is used herein in its conventional meaning in the imaging art to refer to a material having first and second display states differing in at least one optical property, the material being changed from its first to its second display state by application of an electric field to the material. Although the optical property is typically color perceptible to the human eye, it may be another optical property, such as optical transmission, reflectance, luminescence or, in the case of displays intended for machine reading, pseudo-color in the sense of a change in reflectance of electromagnetic wavelengths outside the visible range.
The terms “bistable” and “bistability” are used herein in their conventional meaning in the art to refer to displays comprising display elements having first and second display states differing in at least one optical property, and such that after any given element has been driven, by means of an addressing pulse of finite duration, to assume either its first or second display state, after the addressing pulse has terminated, that state will persist for at least several times, for example at least four times, the minimum duration of the addressing pulse required to change the state of the display element. It is shown in U.S. Pat. No. 7,170,670 that some particle-based electrophoretic displays capable of gray scale are stable not only in their extreme black and white states but also in their intermediate gray states, and the same is true of some other types of electro-optic displays. This type of display is properly called “multi-stable” rather than bistable, although for convenience the term “bistable” may be used herein to cover both bistable and multi-stable displays.
The term “gray state” is used herein in its conventional meaning in the imaging art to refer to a state intermediate two extreme optical states of a pixel, and does not necessarily imply a black-white transition between these two extreme states. For example, several of the E Ink patents and published applications referred to below describe electrophoretic displays in which the extreme states are white and deep blue, so that an intermediate “gray state” would actually be pale blue. Indeed, as already mentioned, the change in optical state may not be a color change at all. The terms “black” and “white” may be used hereinafter to refer to the two extreme optical states of a display (also referred to as “optical rail states”), and should be understood as normally including extreme optical states which are not strictly black and white, for example, the aforementioned white and dark blue states. The term “monochrome” may be used hereinafter to denote a display or drive scheme which only drives pixels to their two extreme optical states with no intervening gray states.
The term “pixel” is used herein in its conventional meaning in the display art to mean the smallest unit of a display capable of generating all the colors which the display itself can show. In a full color display, typically each pixel is composed of a plurality of sub-pixels each of which can display less than all the colors which the display itself can show. For example, in most conventional full color displays, each pixel is composed of a red sub-pixel, a green sub-pixel, a blue sub-pixel, and optionally a white sub-pixel, with each of the sub-pixels being capable of displaying a range of colors from black to the brightest version of its specified color.
Several types of electro-optic displays are known. One type of electro-optic display is a rotating bichromal member type as described, for example, in U.S. Pat. Nos. 5,808,783; 5,777,782; 5,760,761; 6,054,071 6,055,091; 6,097,531; 6,128,124; 6,137,467; and 6,147,791 (although this type of display is often referred to as a “rotating bichromal ball” display, the term “rotating bichromal member” is preferred as more accurate since in some of the patents mentioned above the rotating members are not spherical). Such a display uses a large number of small bodies (typically spherical or cylindrical) which have two or more sections with differing optical characteristics, and an internal dipole. These bodies are suspended within liquid-filled vacuoles within a matrix, the vacuoles being filled with liquid so that the bodies are free to rotate. The appearance of the display is changed by applying an electric field thereto, thus rotating the bodies to various positions and varying which of the sections of the bodies is seen through a viewing surface. This type of electro-optic medium is typically bistable.
Another type of electro-optic display uses an electrochromic medium, for example an electrochromic medium in the form of a nanochromic film comprising an electrode formed at least in part from a semi-conducting metal oxide and a plurality of dye molecules capable of reversible color change attached to the electrode; see, for example O'Regan, B., et al., Nature 1991, 353, 737; and Wood, D., Information Display, 18(3), 24 (March 2002). See also Bach, U., et al., Adv. Mater., 2002, 14(11), 845. Nanochromic films of this type are also described, for example, in U.S. Pat. Nos. 6,301,038; 6,870,657; and 6,950,220. This type of medium is also typically bistable.
Another type of electro-optic display is an electro-wetting display developed by Philips and described in Hayes, R. A., et al., “Video-Speed Electronic Paper Based on Electrowetting”, Nature, 425, 383-385 (2003). It is shown in U.S. Pat. No. 7,420,549 that such electro-wetting displays can be made bistable.
One type of electro-optic display, which has been the subject of intense research and development for a number of years, is the particle-based electrophoretic display, in which a plurality of charged particles move through a fluid under the influence of an electric field. Electrophoretic displays can have attributes of good brightness and contrast, wide viewing angles, state bistability, and low power consumption when compared with liquid crystal displays.
As noted above, electrophoretic media require the presence of a fluid. In most prior art electrophoretic media, this fluid is a liquid, but electrophoretic media can be produced using gaseous fluids; see, for example, Kitamura, T., et al., “Electrical toner 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. Pat. Nos. 7,321,459 and 7,236,291. Such gas-based electrophoretic media appear to be susceptible to the same types of problems due to particle settling as liquid-based electrophoretic media, when the media are used in an orientation which permits such settling, for example in a sign where the medium is disposed in a vertical plane. Indeed, particle settling appears to be a more serious problem in gas-based electrophoretic media than in liquid-based ones, since the lower viscosity of gaseous suspending fluids as compared with liquid ones allows more rapid settling of the electrophoretic particles.
Numerous patents and applications assigned to or in the names of the Massachusetts Institute of Technology (MIT) and E Ink Corporation describe various technologies used in encapsulated electrophoretic and other electro-optic media. Such encapsulated media comprise numerous small capsules, each of which itself comprises an internal phase containing electrophoretically-mobile particles in a fluid medium, and a capsule wall surrounding the internal phase. Typically, the capsules are themselves held within a polymeric binder to form a coherent layer positioned between two electrodes. The technologies described in these patents and applications include:
This application is further related to U.S. Pat. Nos. D485,294; 6,124,851; 6,130,773; 6,177,921; 6,232,950; 6,252,564; 6,312,304; 6,312,971; 6,376,828; 6,392,786; 6,413,790; 6,422,687; 6,445,374; 6,480,182; 6,498,114; 6,506,438; 6,518,949; 6,521,489; 6,535,197; 6,545,291; 6,639,578; 6,657,772; 6,664,944; 6,680,725; 6,683,333; 6,724,519; 6,750,473; 6,816,147; 6,819,471; 6,825,068; 6,831,769; 6,842,167; 6,842,279; 6,842,657; 6,865,010; 6,873,452; 6,909,532; 6,967,640; 6,980,196; 7,012,735; 7,030,412; 7,075,703; 7,106,296; 7,110,163; 7,116,318; 7,148,128; 7,167,155; 7,173,752; 7,176,880; 7,190,008; 7,206,119; 7,223,672; 7,230,751; 7,256,766; 7,259,744; 7,280,094; 7,301,693; 7,304,780; 7,327,511; 7,347,957; 7,349,148; 7,352,353; 7,365,394; 7,365,733; 7,382,363; 7,388,572; 7,401,758; 7,442,587; 7,492,497; 7,535,624; 7,551,346; 7,554,712; 7,583,427; 7,598,173; 7,605,799; 7,636,191; 7,649,674; 7,667,886; 7,672,040; 7,688,497; 7,733,335; 7,785,988; 7,830,592; 7,843,626; 7,859,637; 7,880,958; 7,893,435; 7,898,717; 7,905,977; 7,957,053; 7,986,450; 8,009,344; 8,027,081; 8,049,947; 8,072,675; 8,077,141; 8,089,453; 8,120,836; 8,159,636; 8,208,193; 8,237,892; 8,238,021; 8,362,488; 8,373,211; 8,389,381; 8,395,836; 8,437,069; 8,441,414; 8,456,589; 8,498,042; 8,514,168; 8,547,628; 8,576,162; 8,610,988; 8,714,780; 8,728,266; 8,743,077; 8,754,859; 8,797,258; 8,797,633; 8,797,636; 8,830,560; 8,891,155; 8,969,886; 9,147,364; 9,025,234; 9,025,238; 9,030,374; 9,140,952; 9,152,003; 9,152,004; 9,201,279; 9,223,164; 9,285,648; and 9,310,661; and U.S. Patent Applications Publication Nos. 2002/0060321; 2004/0008179; 2004/0085619; 2004/0105036; 2004/0112525; 2005/0122306; 2005/0122563; 2006/0215106; 2006/0255322; 2007/0052757; 2007/0097489; 2007/0109219; 2008/0061300; 2008/0149271; 2009/0122389; 2009/0315044; 2010/0177396; 2011/0140744; 2011/0187683; 2011/0187689; 2011/0292319; 2013/0250397; 2013/0278900; 2014/0078024; 2014/0139501; 2014/0192000; 2014/0210701; 2014/0300837; 2014/0368753; 2014/0376164; 2015/0171112; 2015/0205178; 2015/0226986; 2015/0227018; 2015/0228666; 2015/0261057; 2015/0356927; 2015/0378235; 2016/077375; 2016/0103380; and 2016/0187759; and International Application Publication No. WO 00/38000; European Patents Nos. 1,099,207 B1 and 1,145,072 B1; all of the above-listed applications are incorporated by reference in their entireties.
This application is also related to U.S. Pat. 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; 8,537,105; 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 Applications Publication Nos. 2003/0102858; 2004/0246562; 2005/0253777; 2007/0070032; 2007/0076289; 2007/0091418; 2007/0103427; 2007/0176912; 2007/0296452; 2008/0024429; 2008/0024482; 2008/0136774; 2008/0169821; 2008/0218471; 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; 2016/0071465; 2016/0078820; 2016/0093253; 2016/0140910; and 2016/0180777; all of the above-listed applications are incorporated by reference in their entireties.
Many of the aforementioned patents and applications recognize that the walls surrounding the discrete microcapsules in an encapsulated electrophoretic medium could be replaced by a continuous phase, thus producing a so-called polymer-dispersed electrophoretic display, in which the electrophoretic medium comprises a plurality of discrete droplets of an electrophoretic fluid and a continuous phase of a polymeric material, and that the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display may be regarded as capsules or microcapsules even though no discrete capsule membrane is associated with each individual droplet; see for example, the aforementioned U.S. Pat. No. 6,866,760. Accordingly, for purposes of the present application, such polymer-dispersed electrophoretic media are regarded as sub-species of encapsulated electrophoretic media.
A related type of electrophoretic display is a so-called “microcell electrophoretic display”. In a microcell electrophoretic display, the charged particles and the fluid are not encapsulated within microcapsules but instead are retained within a plurality of cavities formed within a carrier medium, typically a polymeric film. See, for example, U.S. Pat. Nos. 6,672,921 and 6,788,449, both assigned to Sipix Imaging, Inc.
Although electrophoretic media are often opaque (since, for example, in many electrophoretic media, the particles substantially block transmission of visible light through the display) and operate in a reflective mode, many electrophoretic displays can be made to operate in a so-called “shutter mode” in which one display state is substantially opaque and one is light-transmissive. See, for example, U.S. Pat. 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, which are similar to electrophoretic displays but rely upon variations in electric field strength, can operate in a similar mode; see U.S. Pat. No. 4,418,346. Other types of electro-optic displays may also be capable of operating in shutter mode. Electro-optic media operating in shutter mode may be useful in multi-layer structures for full color displays; in such structures, at least one layer adjacent the viewing surface of the display operates in shutter mode to expose or conceal a second layer more distant from the viewing surface.
An encapsulated electrophoretic display typically does not suffer from the clustering and settling failure mode of traditional electrophoretic devices and provides further advantages, such as the ability to print or coat the display on a wide variety of flexible and rigid substrates. (Use of the word “printing” is intended to include all forms of printing and coating, including, but without limitation: pre-metered coatings such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coating such as knife over roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; silk screen printing processes; electrostatic printing processes; thermal printing processes; ink jet printing processes; electrophoretic deposition (See U.S. Pat. No. 7,339,715); and other similar techniques.) Thus, the resulting display can be flexible. Further, because the display medium can be printed, using a variety of methods, the display itself can be made inexpensively.
Other types of electro-optic materials may also be used in the present invention.
An electrophoretic display normally comprises a layer of electrophoretic material and at least two other layers disposed on opposed sides of the electrophoretic material, one of these two layers being an electrode layer. In most such displays both the layers are electrode layers, and one or both of the electrode layers are patterned to define the pixels of the display. For example, one electrode layer may be patterned into elongate row electrodes and the other into elongate column electrodes running at right angles to the row electrodes, the pixels being defined by the intersections of the row and column electrodes. Alternatively, and more commonly, one electrode layer has the form of a single continuous electrode and the other electrode layer is patterned into a matrix of pixel electrodes, each of which defines one pixel of the display. In another type of electrophoretic display, which is intended for use with a stylus, print head or similar movable electrode separate from the display, only one of the layers adjacent the electrophoretic layer comprises an electrode, the layer on the opposed side of the electrophoretic layer typically being a protective layer intended to prevent the movable electrode damaging the electrophoretic layer.
In yet another embodiment, such as described in U.S. Pat. No. 6,704,133, electrophoretic displays may be constructed with two continuous electrodes and an electrophoretic layer and a photoelectrophoretic layer between the electrodes. Because the photoelectrophoretic material changes resistivity with the absorption of photons, incident light can be used to alter the state of the electrophoretic medium. Such a device is illustrated in
The aforementioned U.S. Pat. No. 6,982,178 describes a method of assembling a solid electro-optic display (including an encapsulated electrophoretic display) which is well adapted for mass production. Essentially, this patent describes a so-called “front plane laminate” (“FPL”) which comprises, in order, a light-transmissive electrically-conductive layer; a layer of a solid electro-optic medium in electrical contact with the electrically-conductive layer; an adhesive layer; and a release sheet. Typically, the light-transmissive electrically-conductive layer will be carried on a light-transmissive substrate, which is preferably flexible, in the sense that the substrate can be manually wrapped around a drum (say) 10 inches (254 mm) in diameter without permanent deformation. The term “light-transmissive” is used in this patent and herein to mean that the layer thus designated transmits sufficient light to enable an observer, looking through that layer, to observe the change in display states of the electro-optic medium, which will normally be viewed through the electrically-conductive layer and adjacent substrate (if present); in cases where the electro-optic medium displays a change in reflectivity at non-visible wavelengths, the term “light-transmissive” should of course be interpreted to refer to transmission of the relevant non-visible wavelengths. The substrate will typically be a polymeric film, and will normally have a thickness in the range of about 1 to about 25 mil (25 to 634 μm), preferably about 2 to about 10 mil (51 to 254 μm). The electrically-conductive layer is conveniently a thin metal or metal oxide layer of, for example, aluminum or ITO, or may be a conductive polymer. Poly (ethylene terephthalate) (PET) films coated with aluminum or ITO are available commercially, for example as “aluminized Mylar” (“Mylar” is a Registered Trade Mark) from E.I. du Pont de Nemours & Company, Wilmington Del., and such commercial materials may be used with good results in the front plane laminate.
It has now been found that remnant voltage is a more general phenomenon in electrophoretic and other impulse-driven electro-optic displays, both in cause(s) and effect(s). It has also been found that DC imbalances may cause long-term lifetime degradation of some electrophoretic displays.
There are multiple potential sources of remnant voltage. It is believed (although some embodiments are in no way limited by this belief), that a primary cause of remnant voltage is ionic polarization within the materials of the various layers forming the display.
Such polarization occurs in various ways. In a first (for convenience, denoted “Type I”) polarization, an ionic double layer is created across or adjacent a material interface. For example, a positive potential at an indium-tin-oxide (“ITO”) electrode may produce a corresponding polarized layer of negative ions in an adjacent laminating adhesive. The decay rate of such a polarization layer is associated with the recombination of separated ions in the lamination adhesive layer. The geometry of such a polarization layer is determined by the shape of the interface, but may be planar in nature.
In a second (“Type II”) type of polarization, nodules, crystals or other kinds of material heterogeneity within a single material can result in regions in which ions can move or less quickly than the surrounding material. The differing rate of ionic migration can result in differing degrees of charge polarization within the bulk of the medium, and polarization may thus occur within a single display component. Such a polarization may be substantially localized in nature or dispersed throughout the layer.
In a third (“Type III”) type of polarization, polarization may occur at any interface that represents a barrier to charge transport of any particular type of ion. One example of such an interface in a microcavity electrophoretic display is the boundary between the electrophoretic suspension including the suspending medium and particles (the “internal phase”) and the surrounding medium including walls, adhesives and binders (the “external phase”). In many electrophoretic displays, the internal phase is a hydrophobic liquid whereas the external phase is a polymer, such as gelatin. Ions that are present in the internal phase may be insoluble and non-diffusible in the external phase and vice versa. On the application of an electric field perpendicular to such an interface, polarization layers of opposite sign will accumulate on either side of the interface. When the applied electric field is removed, the resulting non-equilibrium charge distribution will result in a measurable remnant voltage potential that decays with a relaxation time determined by the mobility of the ions in the two phases on either side of the interface.
Polarization may occur during a drive pulse. Each image update is an event that may affect remnant voltage. A positive waveform voltage can create a remnant voltage across an electro-optic medium that is of the same or opposite polarity (or nearly zero) depending on the specific electro-optic display.
In some instances, the last frame of a driving sequence may contribute the highest level to the polarization of the ink stack. For example, sometimes a last frame can contributes multiple times (e.g., 10×) more remnant charges to the ink stack than a previous frame.
It will be evident from the foregoing discussion that polarization may occur at multiple locations within the electrophoretic or other electro-optic display, each location having its own characteristic spectrum of decay times, principally at interfaces and at material heterogeneities. Depending on the placement of the sources of these voltages (in other words, the polarized charge distribution) relative to the electro-active parts (for example, the electrophoretic suspension), and the degree of electrical coupling between each kind of charge distribution and the motion of the particles through the suspension, or other electro-optic activity, various kinds of polarization will produce more or less deleterious effects. Since an electrophoretic display operates by motion of charged particles, which inherently causes a polarization of the electro-optic layer, in a sense a preferred electrophoretic display is not one in which no remnant voltages are always present in the display, but rather one in which the remnant voltages do not cause objectionable electro-optic behavior. Ideally, the remnant impulse will be minimized and the remnant voltage will decrease below 1 V, and preferably below 0.2 V, within 1 second, and preferably within 50 ms, so that that by introducing a minimal pause between image updates, the electrophoretic display may affect all transitions between optical states without concern for remnant voltage effects. For electrophoretic displays operating at video rates or at voltages below +/−15 V these ideal values should be correspondingly reduced. Similar considerations apply to other types of electro-optic display.
To summarize, remnant voltage as a phenomenon is at least substantially a result of ionic polarization occurring within the display material components, either at interfaces or within the materials themselves. Such polarizations are especially problematic when they persist on a time scale of roughly 50 ms to about an hour or longer. Remnant voltage can present itself as image ghosting or visual artifacts in a variety of ways, with a degree of severity that can vary with the elapsed times between image updates. Remnant voltage can also create a DC imbalance and reduce ultimate display lifetime. The effects of remnant voltage therefore may be deleterious to the quality of the electrophoretic or other electro-optic device and it is desirable to minimize both the remnant voltage itself, and the sensitivity of the optical states of the device to the influence of the remnant voltage.
Imaging film 110 may be disposed between a front electrode 102 and a rear electrode 104. Front electrode 102 may be formed between the imaging film and the front of the display. In some embodiments, front electrode 102 may be transparent. In some embodiments, front electrode 102 may be formed of any suitable transparent material, including, without limitation, indium tin oxide (ITO). Rear electrode 104 may be formed opposite a front electrode 102. In some embodiments, a parasitic capacitance (not shown) may be formed between front electrode 102 and rear electrode 104.
Pixel 100 may be one of a plurality of pixels. The plurality of pixels may be arranged in a two-dimensional array of rows and columns to form a matrix, such that any specific pixel is uniquely defined by the intersection of one specified row and one specified column. In some embodiments, the matrix of pixels may be an “active matrix,” in which each pixel is associated with at least one non-linear circuit element 120. The non-linear circuit element 120 may be coupled between back-plate electrode 104 and an addressing electrode 108. In some embodiments, non-linear element 120 may include a diode and/or a transistor, including, without limitation, a MOSFET. The drain (or source) of the MOSFET may be coupled to back-plate electrode 104, the source (or drain) of the MOSFET may be coupled to addressing electrode 108, and the gate of the MOSFET may be coupled to a driver electrode 106 configured to control the activation and deactivation of the MOSFET. (For simplicity, the terminal of the MOSFET coupled to back-plate electrode 104 will be referred to as the MOSFET's drain, and the terminal of the MOSFET coupled to addressing electrode 108 will be referred to as the MOSFET's source. However, one of ordinary skill in the art will recognize that, in some embodiments, the source and drain of the MOSFET may be interchanged.)
In some embodiments of the active matrix, the addressing electrodes 108 of all the pixels in each column may be connected to a same column electrode, and the driver electrodes 106 of all the pixels in each row may be connected to a same row electrode. The row electrodes may be connected to a row driver, which may select one or more rows of pixels by applying to the selected row electrodes a voltage sufficient to activate the non-linear elements 120 of all the pixels 100 in the selected row(s). The column electrodes may be connected to column drivers, which may place upon the addressing electrode 106 of a selected (activated) pixel a voltage suitable for driving the pixel into a desired optical state. The voltage applied to an addressing electrode 108 may be relative to the voltage applied to the pixel's front-plate electrode 102 (e.g., a voltage of approximately zero volts). In some embodiments, the front-plate electrodes 102 of all the pixels in the active matrix may be coupled to a common electrode.
In some embodiments, the pixels 100 of the active matrix may be written in a row-by-row manner. For example, a row of pixels may be selected by the row driver, and the voltages corresponding to the desired optical states for the row of pixels may be applied to the pixels by the column drivers. After a pre-selected interval known as the “line address time,” the selected row may be deselected, another row may be selected, and the voltages on the column drivers may be changed so that another line of the display is written.
In another view representing the electro-optic medium, referring now to
One way to avoid this optical kickback is to float the pixel at the end of the active drive (i.e., power off the gate, and in some instances the source, of the TFT corresponding to the pixel, thereby isolating the pixel from any conductive path). Avoiding optical kickback may be beneficial for the extreme dark/black and white state as these optical rails (e.g., the two extreme optical states of the electro-optic medium; typically black and white) influence the achievable dynamic range of the display and hence, the fundamental optical quality of the display.
In practice, charges built up within an electrophoretic material due to polarization effect described above may be mitigated to reduce the remnant voltage effect. For example, by reduce the voltage level of the last frame of a driving sequence.
In some embodiments, the change in remnant voltage by an applied driving waveform V(k) with N frames may be predicted as
ΔVrem=Voffset+Σk=1˜NV(k)*b(N−k+1) (1)
Where the change in remnant voltage ΔVrem is the sum of an offset voltage Voffset and a summation of the remnant voltages contributed by each frame of the driving waveform, the offset Voffset being the voltage added due to the gate voltage change and the TFT parasitic capacitances. In practice, each frame of the driving waveform contributes a certain amount of remnant voltage as dictated by the remnant voltage coefficient b, where in some instances, the remnant voltage coefficient b is the highest for the last frame of the drive. The remnant voltage coefficient b may be determined experimentally or calculated mathematically using models such as an Ota circuit model.
Referring now to
In practice, adjusting the voltage amplitude of the last frame of a drive sequence or driving scheme or driving waveform to a right level can result in a reduced remnant charges or voltages generated. Referring now to
ΔVrem, new≥ΔVrem, old (2)
Lnew≥Lold (3)
Where the change in remnant voltage due to applying the new waveform ΔVrem, new is larger than or equal to the change in remnant voltage due to applying the old waveform ΔVrem, old, but it should be noted that since discussed here is a white-to-white transition where negative voltages are used to drive the display pixels and the resulting remnant voltages are negative in value as well, as such, ΔVrem, new≥ΔVrem, old means the change in remnant voltage due to the new waveform is less negative than if the old waveform is applied, because less remnant voltage is generated by the new waveform.
Furthermore, if equation (2) is expressed in terms of equation (1), then
Σk=1˜NV(k)*b(N−k+1+Δk)+Vlow*b(1+Δk)≥Σk=1˜NV(k)*b(N−k+1)Vlow≥Vlow*=[1/b(1+Δk)]*Σk=1˜NV(k)*[b(N−k+1)−b(N−k+1+Δk)] (4)
which means that the low voltage Vlow at the end of a waveform shifted by Δk frames needs to be smaller in magnitude than or equal to Vlow* as defined in Equation (4), while the lightness of the display pixel resulting from the new waveform (Lnew) needs to be whiter than or equal to that of the old waveform (Lold), in order to achieve enhanced lightness at a smaller remnant voltage cost.
In some embodiments, optical kickback can be avoided by not shorting at the end of an active drive, but instead, pulling the voltage applied to the display pixel to a lower voltage of the same polarity as the drive pulse that does not results in optical kickback, and is small enough to avoid excessive build-up of residual charges. The techniques described herein can be particularly effective for electro-optic displays having an electrophoretic medium incorporating only types of colored pigment particles. In some embodiments, the methods described herein are carried out on black-and-white electro-optic displays having an electrophoretic medium incorporating only charged black pigment particles and charged white pigment particles.
In some embodiments, in constructing a waveform to minimize the optical kickback and the residual charges, one may select a wVH≤−10V, wtH>20 ms (wVH, wtH) pair such that the white optical rail is reached.
In some embodiments, values for wVH and wtH can be selected based on the plots shown in
The same methodology with bVL in the range of 0<bVL≤10V and btL>20 ms can be employed for the black rail. Furthermore, a minimized wtL>20 ms and btL>20 ms may be selected such that the residual charge build-up on the module is minimized. A minimum wtL and btL are desired here for this special waveform update to reduce impact on the total waveform update time. In some embodiments, a value for wtL can be selected based on the plots shown in
In some embodiments, the selected (wVL, wtL) pair may be fixed for a given ink platform at the end of a normal pulse drive dictated by the (wVH, wtH) pair. Similarly the selected (bVL, btL) pair may be fixed for a given ink platform at the end of a normal pulse drive dictated by the (bVH, btH) pair. This configuration provides the flexibility to use rail voltage modulation (as given in the preceding implementation section) to achieve the desired low voltage setting with an active matrix display. In addition, an impulse potential in V·ms can be used as a measure to maintain DC balancing of the driving waveform, where this impulse potential may be defined as:
impulse potential V·ms (drive pulse to white)=wVH*wtH+wVL*wtL
impulse potential V·ms (drive pulse to black)=bVH*btH+bVL*btL
Finally, one may choose to keep the display pixels in an electrically floating state after the completion of a drive waveform.
In practice, the subject matter disclosed herein may be implemented as illustrated in
In another embodiment, for an active matrix display, a waveform may be implemented by selecting wVH, wVL, bVH and bVL values for wtH, wtL, btH and btL durations with wtH, wtL, btH and btL being multiples of the frame time by modulating the supply rail voltages (i.e. VPOS and VNEG) as shown in
Referring now to
It will be apparent to those skilled in the art that numerous changes and modifications can be made to the specific embodiments of the invention described above without departing from the scope of the invention. Accordingly, the whole of the foregoing description is to be interpreted in an illustrative and not in a limitative sense.
This application claims priority to U.S. Provisional Application No. 63/234,295 filed Aug. 18, 2021, and to U.S. Provisional Application No. 63/336,331 filed Apr. 29, 2022. The entire disclosures of the aforementioned provisional applications are incorporated by reference herein.
Number | Name | Date | Kind |
---|---|---|---|
4418346 | Batchelder | Nov 1983 | A |
5760761 | Sheridon | Jun 1998 | A |
5777782 | Sheridon | Jul 1998 | A |
5808783 | Crowley | Sep 1998 | A |
5872552 | Gordon, II et al. | Feb 1999 | A |
5930026 | Jacobson et al. | Jul 1999 | A |
6017584 | Albert et al. | Jan 2000 | A |
6054071 | Mikkelsen, Jr. | Apr 2000 | A |
6055091 | Sheridon et al. | Apr 2000 | A |
6097531 | Sheridon | Aug 2000 | A |
6124851 | Jacobson | Sep 2000 | A |
6128124 | Silverman | Oct 2000 | A |
6130774 | Albert et al. | Oct 2000 | A |
6137467 | Sheridon et al. | Oct 2000 | A |
6144361 | Gordon, II et al. | Nov 2000 | A |
6147791 | Sheridon | Nov 2000 | A |
6177921 | Comiskey et al. | Jan 2001 | B1 |
6184856 | Gordon, II et al. | Feb 2001 | B1 |
6225971 | Gordon, II et al. | May 2001 | B1 |
6232950 | Albert et al. | May 2001 | B1 |
6241921 | Jacobson et al. | Jun 2001 | B1 |
6252564 | Albert et al. | Jun 2001 | B1 |
6271823 | Gordon, II et al. | Aug 2001 | B1 |
6301038 | Fitzmaurice et al. | Oct 2001 | B1 |
6312304 | Duthaler et al. | Nov 2001 | B1 |
6312971 | Amundson et al. | Nov 2001 | B1 |
6376828 | Comiskey | Apr 2002 | B1 |
6392786 | Albert | May 2002 | B1 |
6413790 | Duthaler et al. | Jul 2002 | B1 |
6422687 | Jacobson | Jul 2002 | B1 |
6445489 | Jacobson et al. | Sep 2002 | B1 |
6498114 | Amundson et al. | Dec 2002 | B1 |
6504524 | Gates et al. | Jan 2003 | B1 |
6506438 | Duthaler et al. | Jan 2003 | B2 |
6512354 | Jacobson et al. | Jan 2003 | B2 |
6518949 | Drzaic | Feb 2003 | B2 |
6521489 | Duthaler et al. | Feb 2003 | B2 |
6531997 | Gates et al. | Mar 2003 | B1 |
6545291 | Amundson et al. | Apr 2003 | B1 |
6639578 | Comiskey et al. | Oct 2003 | B1 |
6657772 | Loxley | Dec 2003 | B2 |
6664944 | Albert et al. | Dec 2003 | B1 |
D485294 | Albert | Jan 2004 | S |
6672921 | Liang et al. | Jan 2004 | B1 |
6683333 | Kazlas et al. | Jan 2004 | B2 |
6704133 | Gates et al. | Mar 2004 | B2 |
6724519 | Comiskey et al. | Apr 2004 | B1 |
6753999 | Zehner et al. | Jun 2004 | B2 |
6788449 | Liang et al. | Sep 2004 | B2 |
6816147 | Albert | Nov 2004 | B2 |
6819471 | Amundson et al. | Nov 2004 | B2 |
6825068 | Denis et al. | Nov 2004 | B2 |
6825970 | Goenaga et al. | Nov 2004 | B2 |
6831769 | Holman et al. | Dec 2004 | B2 |
6842279 | Amundson | Jan 2005 | B2 |
6842657 | Drzaic et al. | Jan 2005 | B1 |
6865010 | Duthaler et al. | Mar 2005 | B2 |
6866760 | Paolini, Jr. et al. | Mar 2005 | B2 |
6870657 | Fitzmaurice et al. | Mar 2005 | B1 |
6873452 | Tseng et al. | Mar 2005 | B2 |
6900851 | Morrison et al. | May 2005 | B2 |
6909532 | Chung et al. | Jun 2005 | B2 |
6922276 | Zhang et al. | Jul 2005 | B2 |
6950220 | Abramson et al. | Sep 2005 | B2 |
6967640 | Albert et al. | Nov 2005 | B2 |
6980196 | Turner et al. | Dec 2005 | B1 |
6982178 | LeCain et al. | Jan 2006 | B2 |
6995550 | Jacobson et al. | Feb 2006 | B2 |
7002728 | Pullen et al. | Feb 2006 | B2 |
7012600 | Zehner et al. | Mar 2006 | B2 |
7012735 | Honeyman | Mar 2006 | B2 |
7023420 | Comiskey et al. | Apr 2006 | B2 |
7030412 | Drzaic et al. | Apr 2006 | B1 |
7034783 | Gates et al. | Apr 2006 | B2 |
7061166 | Kuniyasu | Jun 2006 | B2 |
7061662 | Chung et al. | Jun 2006 | B2 |
7072095 | Liang et al. | Jul 2006 | B2 |
7075502 | Drzaic et al. | Jul 2006 | B1 |
7075703 | O'Neil et al. | Jul 2006 | B2 |
7106296 | Jacobson | Sep 2006 | B1 |
7110163 | Webber et al. | Sep 2006 | B2 |
7116318 | Amundson et al. | Oct 2006 | B2 |
7116466 | Whitesides et al. | Oct 2006 | B2 |
7119772 | Amundson et al. | Oct 2006 | B2 |
7144942 | Zang et al. | Dec 2006 | B2 |
7148128 | Jacobson | Dec 2006 | B2 |
7167155 | Albert et al. | Jan 2007 | B1 |
7170670 | Webber | Jan 2007 | B2 |
7173752 | Doshi et al. | Feb 2007 | B2 |
7176880 | Amundson et al. | Feb 2007 | B2 |
7177066 | Chung et al. | Feb 2007 | B2 |
7190008 | Amundson et al. | Mar 2007 | B2 |
7193625 | Danner et al. | Mar 2007 | B2 |
7202847 | Gates | Apr 2007 | B2 |
7206119 | Honeyman et al. | Apr 2007 | B2 |
7223672 | Kazlas et al. | May 2007 | B2 |
7230751 | Whitesides et al. | Jun 2007 | B2 |
7236291 | Kaga et al. | Jun 2007 | B2 |
7256766 | Albert et al. | Aug 2007 | B2 |
7259744 | Arango et al. | Aug 2007 | B2 |
7301693 | Chaug et al. | Nov 2007 | B2 |
7304780 | Liu et al. | Dec 2007 | B2 |
7312784 | Baucom et al. | Dec 2007 | B2 |
7321459 | Masuda et al. | Jan 2008 | B2 |
7327346 | Chung et al. | Feb 2008 | B2 |
7327511 | Whitesides et al. | Feb 2008 | B2 |
7339715 | Webber et al. | Mar 2008 | B2 |
7347957 | Wu et al. | Mar 2008 | B2 |
7352353 | Albert et al. | Apr 2008 | B2 |
7365733 | Duthaler et al. | Apr 2008 | B2 |
7388572 | Duthaler et al. | Jun 2008 | B2 |
7401758 | Liang et al. | Jul 2008 | B2 |
7408699 | Wang et al. | Aug 2008 | B2 |
7411719 | Paolini, Jr. et al. | Aug 2008 | B2 |
7420549 | Jacobson et al. | Sep 2008 | B2 |
7453445 | Amundson | Nov 2008 | B2 |
7492339 | Amundson | Feb 2009 | B2 |
7492497 | Paolini, Jr. et al. | Feb 2009 | B2 |
7528822 | Amundson et al. | May 2009 | B2 |
7535624 | Amundson et al. | May 2009 | B2 |
7551346 | Fazel et al. | Jun 2009 | B2 |
7554712 | Patry et al. | Jun 2009 | B2 |
7560004 | Pereira et al. | Jul 2009 | B2 |
7583251 | Arango et al. | Sep 2009 | B2 |
7583427 | Danner et al. | Sep 2009 | B2 |
7598173 | Ritenour et al. | Oct 2009 | B2 |
7602374 | Zehner et al. | Oct 2009 | B2 |
7612760 | Kawai | Nov 2009 | B2 |
7636191 | Duthaler et al. | Dec 2009 | B2 |
7649674 | Danner et al. | Jan 2010 | B2 |
7667886 | Danner et al. | Feb 2010 | B2 |
7672040 | Sohn et al. | Mar 2010 | B2 |
7679599 | Kawai | Mar 2010 | B2 |
7679813 | Liang et al. | Mar 2010 | B2 |
7679814 | Paolini, Jr. et al. | Mar 2010 | B2 |
7683606 | Kang et al. | Mar 2010 | B2 |
7688497 | Danner et al. | Mar 2010 | B2 |
7715088 | Liang et al. | May 2010 | B2 |
7830592 | Sprague et al. | Nov 2010 | B1 |
7839564 | Whitesides et al. | Nov 2010 | B2 |
7859637 | Amundson et al. | Dec 2010 | B2 |
7859742 | Chiu et al. | Dec 2010 | B1 |
7880958 | Zang et al. | Feb 2011 | B2 |
7893435 | Kazlas et al. | Feb 2011 | B2 |
7905977 | Qi et al. | Mar 2011 | B2 |
7910175 | Webber | Mar 2011 | B2 |
7952557 | Amundson | May 2011 | B2 |
7952790 | Honeyman et al. | May 2011 | B2 |
7982479 | Wang et al. | Jul 2011 | B2 |
7986450 | Cao et al. | Jul 2011 | B2 |
7999787 | Amundson et al. | Aug 2011 | B2 |
8009344 | Danner et al. | Aug 2011 | B2 |
8009348 | Zehner et al. | Aug 2011 | B2 |
8040594 | Paolini, Jr. et al. | Oct 2011 | B2 |
8049947 | Danner et al. | Nov 2011 | B2 |
8054526 | Bouchard | Nov 2011 | B2 |
8072675 | Lin et al. | Dec 2011 | B2 |
8098418 | Paolini, Jr. et al. | Jan 2012 | B2 |
8120836 | Lin et al. | Feb 2012 | B2 |
8125501 | Amundson et al. | Feb 2012 | B2 |
8139050 | Jacobson et al. | Mar 2012 | B2 |
8159636 | Sun et al. | Apr 2012 | B2 |
8174490 | Whitesides et al. | May 2012 | B2 |
8237892 | Sprague et al. | Aug 2012 | B1 |
8243013 | Sprague et al. | Aug 2012 | B1 |
8274472 | Wang et al. | Sep 2012 | B1 |
8289250 | Zehner et al. | Oct 2012 | B2 |
8300006 | Zhou et al. | Oct 2012 | B2 |
8314784 | Ohkami et al. | Nov 2012 | B2 |
8319759 | Jacobson et al. | Nov 2012 | B2 |
8362488 | Chaug et al. | Jan 2013 | B2 |
8363299 | Paolini, Jr. et al. | Jan 2013 | B2 |
8373649 | Low et al. | Feb 2013 | B2 |
8384658 | Albert et al. | Feb 2013 | B2 |
8395836 | Lin | Mar 2013 | B2 |
8437069 | Lin | May 2013 | B2 |
8441414 | Lin | May 2013 | B2 |
8456414 | Lin et al. | Jun 2013 | B2 |
8456589 | Sprague et al. | Jun 2013 | B1 |
8462102 | Wong et al. | Jun 2013 | B2 |
8514168 | Chung et al. | Aug 2013 | B2 |
8537105 | Chiu et al. | Sep 2013 | B2 |
8547628 | Wu et al. | Oct 2013 | B2 |
8558783 | Wilcox et al. | Oct 2013 | B2 |
8558786 | Lin | Oct 2013 | B2 |
8558855 | Sprague et al. | Oct 2013 | B2 |
8564531 | Ozawa | Oct 2013 | B2 |
8576162 | Kang | Nov 2013 | B2 |
8576164 | Sprague et al. | Nov 2013 | B2 |
8576259 | Lin et al. | Nov 2013 | B2 |
8576470 | Paolini, Jr. et al. | Nov 2013 | B2 |
8576476 | Telfer et al. | Nov 2013 | B2 |
8605032 | Liu et al. | Dec 2013 | B2 |
8610988 | Zehner et al. | Dec 2013 | B2 |
8665206 | Lin et al. | Mar 2014 | B2 |
8681191 | Yang et al. | Mar 2014 | B2 |
8714780 | Ho et al. | May 2014 | B2 |
8728266 | Danner et al. | May 2014 | B2 |
8743077 | Sprague | Jun 2014 | B1 |
8754859 | Gates et al. | Jun 2014 | B2 |
8797258 | Sprague | Aug 2014 | B2 |
8797633 | Sprague et al. | Aug 2014 | B1 |
8797634 | Paolini, Jr. et al. | Aug 2014 | B2 |
8797636 | Yang et al. | Aug 2014 | B2 |
8810525 | Sprague | Aug 2014 | B2 |
8873129 | Paolini, Jr. et al. | Oct 2014 | B2 |
8902153 | Bouchard et al. | Dec 2014 | B2 |
8928562 | Gates et al. | Jan 2015 | B2 |
8928641 | Chiu et al. | Jan 2015 | B2 |
8976444 | Zhang et al. | Mar 2015 | B2 |
9013394 | Lin | Apr 2015 | B2 |
9019197 | Lin | Apr 2015 | B2 |
9019198 | Lin et al. | Apr 2015 | B2 |
9019318 | Sprague et al. | Apr 2015 | B2 |
9025234 | Lin | May 2015 | B2 |
9025238 | Chan et al. | May 2015 | B2 |
9030374 | Sprague et al. | May 2015 | B2 |
9082352 | Cheng et al. | Jul 2015 | B2 |
9140952 | Sprague et al. | Sep 2015 | B2 |
9147364 | Wu et al. | Sep 2015 | B2 |
9152004 | Paolini, Jr. et al. | Oct 2015 | B2 |
9199441 | Danner | Dec 2015 | B2 |
9201279 | Wu et al. | Dec 2015 | B2 |
9218773 | Sun et al. | Dec 2015 | B2 |
9223164 | Lai et al. | Dec 2015 | B2 |
9224338 | Chan et al. | Dec 2015 | B2 |
9224342 | Sprague et al. | Dec 2015 | B2 |
9224344 | Chung et al. | Dec 2015 | B2 |
9230492 | Harrington et al. | Jan 2016 | B2 |
9262973 | Wu et al. | Feb 2016 | B2 |
9279906 | Kang | Mar 2016 | B2 |
9285648 | Liu et al. | Mar 2016 | B2 |
9299294 | Lin et al. | Mar 2016 | B2 |
9310661 | Wu et al. | Apr 2016 | B2 |
9373289 | Sprague et al. | Jun 2016 | B2 |
9390066 | Smith et al. | Jul 2016 | B2 |
9390661 | Chiu et al. | Jul 2016 | B2 |
9454057 | Wu et al. | Sep 2016 | B2 |
9460666 | Sprague et al. | Oct 2016 | B2 |
9495918 | Harrington et al. | Nov 2016 | B2 |
9501981 | Lin et al. | Nov 2016 | B2 |
9513743 | Sjodin et al. | Dec 2016 | B2 |
9514667 | Lin | Dec 2016 | B2 |
9529240 | Paolini, Jr. et al. | Dec 2016 | B2 |
9582041 | Cheng et al. | Feb 2017 | B2 |
9620048 | Sim et al. | Apr 2017 | B2 |
9620066 | Bishop | Apr 2017 | B2 |
9632373 | Huang et al. | Apr 2017 | B2 |
9666142 | Hung | May 2017 | B2 |
9671635 | Paolini, Jr. | Jun 2017 | B2 |
9672766 | Sjodin | Jun 2017 | B2 |
9691333 | Cheng et al. | Jun 2017 | B2 |
9721495 | Harrington et al. | Aug 2017 | B2 |
9792861 | Chang et al. | Oct 2017 | B2 |
9792862 | Hung et al. | Oct 2017 | B2 |
10037735 | Amundson | Jul 2018 | B2 |
10048563 | Paolini, Jr. et al. | Aug 2018 | B2 |
10190743 | Hertel et al. | Jan 2019 | B2 |
10229641 | Yang et al. | Mar 2019 | B2 |
10319313 | Harris et al. | Jun 2019 | B2 |
10339876 | Lin et al. | Jul 2019 | B2 |
10372008 | Telfer et al. | Aug 2019 | B2 |
10446585 | Harris et al. | Oct 2019 | B2 |
10466564 | Kayal et al. | Nov 2019 | B2 |
10475396 | Sim et al. | Nov 2019 | B2 |
10613407 | Lin et al. | Apr 2020 | B2 |
10672350 | Amundson et al. | Jun 2020 | B2 |
20020060321 | Kazlas et al. | May 2002 | A1 |
20030102858 | Jacobson et al. | Jun 2003 | A1 |
20040085619 | Wu et al. | May 2004 | A1 |
20040105036 | Danner et al. | Jun 2004 | A1 |
20040246562 | Chung et al. | Dec 2004 | A1 |
20050001812 | Amundson | Jan 2005 | A1 |
20050122306 | Wilcox et al. | Jun 2005 | A1 |
20050122563 | Honeyman et al. | Jun 2005 | A1 |
20050253777 | Zehner et al. | Nov 2005 | A1 |
20060255322 | Wu et al. | Nov 2006 | A1 |
20070103427 | Zhou et al. | May 2007 | A1 |
20070176912 | Beames et al. | Aug 2007 | A1 |
20080024429 | Zehner | Jan 2008 | A1 |
20080024482 | Gates et al. | Jan 2008 | A1 |
20080043318 | Whitesides et al. | Feb 2008 | A1 |
20080136774 | Harris et al. | Jun 2008 | A1 |
20080303780 | Sprague et al. | Dec 2008 | A1 |
20090122389 | Whitesides et al. | May 2009 | A1 |
20090225398 | Duthaler et al. | Sep 2009 | A1 |
20090322721 | Zehner et al. | Dec 2009 | A1 |
20100156780 | Jacobson et al. | Jun 2010 | A1 |
20100177396 | Lin | Jul 2010 | A1 |
20100194733 | Lin et al. | Aug 2010 | A1 |
20100194789 | Lin et al. | Aug 2010 | A1 |
20100265561 | Gates et al. | Oct 2010 | A1 |
20110012889 | Miyamoto | Jan 2011 | A1 |
20110063314 | Chiu et al. | Mar 2011 | A1 |
20110175875 | Lin et al. | Jul 2011 | A1 |
20110221740 | Yang et al. | Sep 2011 | A1 |
20110292319 | Cole | Dec 2011 | A1 |
20120001957 | Liu et al. | Jan 2012 | A1 |
20120098740 | Chiu et al. | Apr 2012 | A1 |
20130063333 | Arango et al. | Mar 2013 | A1 |
20130249782 | Wu et al. | Sep 2013 | A1 |
20140078024 | Paolini, Jr. et al. | Mar 2014 | A1 |
20140192000 | Hung et al. | Jul 2014 | A1 |
20140204012 | Wu et al. | Jul 2014 | A1 |
20140210701 | Wu et al. | Jul 2014 | A1 |
20140240210 | Wu et al. | Aug 2014 | A1 |
20140253425 | Zalesky et al. | Sep 2014 | A1 |
20140293398 | Wang et al. | Oct 2014 | A1 |
20150262255 | Khajehnouri et al. | Sep 2015 | A1 |
20160077375 | Lin | Mar 2016 | A1 |
20160180777 | Lin et al. | Jun 2016 | A1 |
20190266956 | Sim et al. | Aug 2019 | A1 |
20200209703 | Lin | Jul 2020 | A1 |
Number | Date | Country |
---|---|---|
1999067678 | Dec 1999 | WO |
2000005704 | Feb 2000 | WO |
2000038000 | Jun 2000 | WO |
Entry |
---|
Korean Intellectual Property Office, “International Search Report and Written Opinion”, PCT/US2022/040697, dated Dec. 5, 2022. |
O'Regan, B. et al., “A Low Cost, High-efficiency Solar Cell Based on Dye-sensitized colloidal TiO2 Films”, Nature, vol. 353, pp. 737-740 (Oct. 24, 1991). |
Wood, D., “An Electrochromic Renaissance?” Information Display, 18(3), 24 (Mar. 2002). |
Bach, Udo. et al., “Nanomaterials-Based Electrochromics for Paper-Quality Displays”, Adv. Mater, vol. 14, No. 11, pp. 345-348, (Jun. 5, 2002). |
Hayes, R.A. et al., “Video-Speed Electronic Paper Based on Electrowetting”, Nature, vol. 425, No. 25, pp. 383-385 (Sep. 2003). |
Kitamura, T. et al., “Electrical toner movement for electronic paper-like display”, Asia Display/IDW '01, pp. 1517-1520, Paper HCS1-1 (2001). |
Yamaguchi, Y. et al., “Toner display using insulative particles charged triboelectrically”, Asia Display/IDW '01, pp. 1729-1730, Paper AMD4-4 (2001). |
Taiwan Intellectual Property Office, “Notification For the Opinion of Examination”, Taiwan Patent Appl. No. 111131149, dated Oct. 17, 2023, 14 pages. |
Number | Date | Country | |
---|---|---|---|
20230056258 A1 | Feb 2023 | US |
Number | Date | Country | |
---|---|---|---|
63336331 | Apr 2022 | US | |
63234295 | Aug 2021 | US |