Reflective display and projected capacitive touch sensor with shared transparent electrodes

Abstract

An electro-optical display device (300) having a touch function has a multilayer stack including, in order: a first electrode layer (224) at a viewing surface of the touch screen electro-optical display device (300); a dielectric layer (206); a second electrode layer (226); a semiconductive layer (308); an electro-optic dielectric layer; and a third electrode layer. The second electrode layer, the semi-conductive layer, the electro-optic dielectric layer (216), and a third electrode layer formed on the backplane (222) form an electro-optic device (300) in which the electro-optic dielectric layer (216) is addressed by applying a drive voltage to the third electrode layer while maintaining the voltage on the second electrode layer (226) constant. The first electrode layer (224), the dielectric layer (206), and the second electrode layer (226) form a capacitive touch sensor that detects a touch input by sensing a change in capacitance at a touch point on the first electrode layer (224).

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 546,551, filed October 31, 2023, entitled “REFLECTIVE DISPLAY AND PROJECTED CAPACITIVE TOUCH SENSOR WITH SHARED TRANSPARENT ELECTRODE”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention generally relates to reflective electro-optic displays with touch functionality, and more specifically, to electrophoretic display devices having projected capacitive touch sensors using shared transparent electrodes to improve optical performance. Background Technology

[0004] Electrophoretic displays change color by modifying the position of charged colored particles relative to a light-transmitting viewing surface. They are often called "electronic paper" or "ePaper" because the resulting display has high contrast and is readable in sunlight, much like ink on paper. Electrophoretic displays have been widely adopted in e-readers such as the AMAZON KINDLE® because they provide a book-like reading experience, use very little power, and allow users to carry a library of hundreds of books in a lightweight handheld device.

[0005] Electrophoretic displays and other modern electronic displays typically include touch sensors for receiving user touch input. Touch sensor technologies include resistive touch sensors (which detect changes in resistance between two surfaces caused by mechanical deformation), suppressed total internal reflection (which detects interruptions in total internal reflection through the optical coupling of an object to a waveguide at the display surface), surface acoustic wave detection, and the most common capacitive sensing method. One of the most common capacitive sensing techniques is projected capacitive sensing, which uses an array of rows and columns of thin conductive electrodes separated by a non-conductive material. Since the human body is conductive, touching or approaching the sensing surface with a fingertip changes the coupling capacitance between the electrode lines at the intersections of the grid array's rows and columns. This capacitance change can be measured in several ways, such as by measuring the change in grid voltage for a given charge or the change in the RC time constant. Projected capacitive sensing is a particularly useful technique because, unlike earlier capacitive sensing methods, it is capable of detecting multiple simultaneous touch events.

[0006] This disclosure describes combining the functionality of one of the electrode layers of a projected capacitive touch sensor array with the functionality of a transparent driving electrode of an electrophoretic display to improve optical performance. Summary of the Invention

[0007] According to a first aspect of the present invention, a touch-enabled electro-optic display device includes multiple stacked layers, which are sequentially: a first electrode layer at the viewing surface of the touchscreen electro-optic display device; a dielectric layer; a second electrode layer; a semiconductive layer; an electro-optic dielectric layer; and a third electrode layer. The second electrode layer, the semiconductive layer, the electro-optic dielectric layer, and the third electrode layer form an electro-optic device, wherein the electro-optic dielectric layer is addressed by applying a driving voltage to the third electrode layer while maintaining a constant voltage on the second electrode layer. The first electrode layer, the dielectric layer, and the second electrode layer form a capacitive touch sensor, which detects touch input by sensing changes in capacitance at a touch point on the first electrode layer.

[0008] In one or more embodiments, the first electrode layer and the second electrode layer include a plurality of electrodes forming a grid of rows and columns.

[0009] In one or more embodiments, a plurality of electrodes of the second electrode layer are disposed in a semiconductive layer configured to promote blooming in the gap between adjacent electrodes.

[0010] In one or more embodiments, the semiconducting layer includes an ion-conducting layer.

[0011] In one or more embodiments, the ion-conducting layer comprises a polymer material containing ion dopants.

[0012] In one or more embodiments, the semiconductive layer has a thickness of approximately 2 to 50 micrometers and / or approximately 10 micrometers. 3 Up to 10 7 Resistivity in Ω⋅cm.

[0013] In one or more embodiments, the semiconductive layer has a thickness of approximately 5 to 25 micrometers.

[0014] In one or more embodiments, the electro-optical device and the capacitive touch sensor operate at different times.

[0015] In one or more embodiments, each time frame for refreshing the electro-optical device includes a first time portion for addressing the optical medium layer and a separate second time portion for detecting touch input.

[0016] In one or more embodiments, the device further includes a light guide plate and a cover lens on the side of the first electrode layer opposite to the dielectric layer.

[0017] In one or more embodiments, the third electrode layer includes a pixel electrode array in the backplane.

[0018] In one or more embodiments, the electro-optic medium comprises charged pigment particles dispersed in a nonpolar solvent.

[0019] In one or more embodiments, the electro-optic dielectric layer includes an encapsulated electrophoretic dielectric.

[0020] In one or more embodiments, the encapsulated electrophoretic medium includes an electrophoretic medium encapsulated in a microcapsule or microcup.

[0021] In one or more embodiments, the electro-optic medium is bistable.

[0022] In one or more embodiments, the first electrode layer, the second electrode layer, or the third electrode layer comprises (a) a material selected from the group consisting of tin alumina, indium tin oxide, poly(3,4-ethylenedioxythiophene) and combinations thereof, (b) an organic material, (c) a composite material, or (d) a sparse mesh.

[0023] In one or more embodiments, the device does not contain indium tin oxide.

[0024] In one or more embodiments, the first electrode layer and the second electrode layer are transparent.

[0025] According to another aspect of the present invention, a method for manufacturing a touchscreen electro-optic display device includes the following steps: (a) providing an electro-optic dielectric layer; (b) laminating one side of the electro-optic dielectric layer onto a pixelated backplane; and (c) laminating the opposite side of the electro-optic dielectric layer onto a layered structure, the layered structure including a first electrode layer, a second electrode layer, and a dielectric layer between the first electrode layer and the second electrode layer, wherein the second electrode layer is adjacent to the electro-optic dielectric layer, and the first electrode layer is located at the viewing surface of the touchscreen electro-optic display device, wherein the first electrode layer and the second electrode layer include a plurality of electrodes forming a row and column grid, and wherein the plurality of electrodes of the second electrode layer are disposed in a semiconductive layer configured to promote halos in the gaps between the electrodes.

[0026] According to another aspect of the present invention, a method for manufacturing a touchscreen electro-optic display device includes the following steps: (a) providing an electro-optic dielectric layer; (b) laminating one side of the electro-optic dielectric layer onto a layered structure including a first electrode layer, a second electrode layer, and a dielectric layer between the first electrode layer and the second electrode layer, wherein the second electrode layer is adjacent to the electro-optic dielectric layer, and the first electrode layer is located at the viewing surface of the touchscreen electro-optic display device, wherein the first electrode layer and the second electrode layer include a plurality of electrodes forming a row and column grid, and wherein the plurality of electrodes of the second electrode layer are disposed in a semiconductive layer configured to promote halos in the gaps between the electrodes; and (c) laminating the opposite side of the electro-optic dielectric layer onto a pixelated backplane.

[0027] In one or more embodiments, providing an electro-optic dielectric layer includes: (i) imprinting microcuplets on a sublayer disposed on a substrate; (ii) filling the microcuplets with an electrophoretic fluid; and (iii) sealing the microcuplets with a polymer sealing layer.

[0028] In one or more embodiments, providing an electro-optic dielectric layer includes: encapsulating an electrophoretic dielectric in microcapsules and distributing the microcapsules in an adhesive to form a slurry for coating onto a pixelated backplane or layered structure.

[0029] In one or more embodiments, laminating one side of the electro-optic dielectric layer onto the pixelated backplane includes: (i) laminating a substrate coated with an adhesive layer onto a polymer sealing layer of the electro-optic dielectric layer; (ii) removing the substrate; and (iii) laminating the pixelated backplane onto the adhesive layer.

[0030] In one or more embodiments, laminating the opposite sides of the electro-optic dielectric layer onto the layered structure includes laminating the bottom layer of the electro-optic dielectric layer onto a second electrode layer of the layered structure.

[0031] In one or more embodiments, the method further includes attaching a light guide plate and a cover lens to the side of the first electrode layer opposite to the dielectric layer. Attached Figure Description

[0032] Figure 1 This is a simplified diagram illustrating an exemplary prior art electrophoresis apparatus.

[0033] Figure 2 This is a simplified diagram illustrating an exemplary prior art thin-film transistor backplane array for driving an electrophoresis apparatus.

[0034] Figure 3A and 3B These are simplified cross-sectional views and plan views illustrating the basic design of an exemplary prior art projected capacitive touch sensor.

[0035] Figure 4 This is a simplified cross-sectional view illustrating an exemplary prior art display module with a projected capacitive touch sensor.

[0036] Figure 5 This is a simplified cross-sectional view illustrating an exemplary reflective display module having a projected capacitive touch sensor according to one or more embodiments.

[0037] Figures 6A-6E This is a simplified cross-sectional view illustrating an exemplary process for manufacturing a reflective display module having a projected capacitive touch sensor according to one or more embodiments.

[0038] In all the accompanying drawings, the same reference numerals denote the same elements. Detailed Implementation

[0039] The various embodiments disclosed herein relate to electrophoretic or other reflective displays having a projected capacitive touch sensor that uses a shared transparent electrode to improve optical performance.

[0040] Electrophoretic displays have been a subject of in-depth research and development for many years. 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 can offer advantages such as good brightness and contrast, wide viewing angles, bistable states, and low power consumption. However, long-term image quality issues have hindered their widespread use. For example, the particles constituting an electrophoretic display tend to settle, leading to a shorter lifespan for these displays.

[0041] As mentioned 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 generated using a gaseous fluid; 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. Patents 7,321,459 and 7,236,291. When such gas-based electrophoretic media are used in a direction that allows for this sedimentation, such as in a marker where the media is set in a vertical plane, such media appear to be susceptible to the same type of problems caused by particle sedimentation as those in 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 gaseous suspensions have lower viscosity than liquid suspensions, allowing electrophoretic particles to settle more quickly.

[0042] Numerous patents and applications transferred to or in the name of MIT and Einkel describe various techniques used in encapsulated electrophoresis and other electro-optic media. Such encapsulated media comprise a plurality of small capsules, each capsule itself containing an inner phase and a capsule wall surrounding that inner phase, which comprises particles that move electrophoretically in a fluid medium. Typically, the capsules themselves are held within a polymer binder to form a coherent layer located between two electrodes. The techniques described in these patents and applications include:

[0043] (a) Electrophoretic particles, fluids, and fluid additives; see, for example, U.S. Patent Nos. 7,002,728 and 7,679,814;

[0044] (b) Encapsulation, adhesives, and encapsulation processes; see, for example, U.S. Patent Nos. 6,922,276 and 7,411,719;

[0045] (c) Microunit structures, wall materials, and methods of forming microunits; see, for example, U.S. Patent Nos. 7,072,095 and 9,279,906;

[0046] (d) Methods for filling and sealing microcells; see, for example, U.S. Patent Nos. 7,144,942 and 7,715,088;

[0047] (e) Films and subassemblies containing electro-optic materials; see, for example, U.S. Patent Nos. 6,982,178 and 7,839,564;

[0048] (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;

[0049] (g) Color formation and color adjustment; see, for example, U.S. Patents 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; 7,952,7 90; 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 No. 2008 / 004331 8; 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;

[0050] (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; 7,3 12,794; 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;8,5 14,168; 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 Publications 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 / 0322 721; 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 / 007074 4; 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 applications may be referred to below as MEDEOD (Methods for Driving Electro-optic Displays) applications)).

[0051] (i) Applications of displays; see, for example, U.S. Patent Nos. 7,312,784 and 8,009,348; and

[0052] (j) Non-electrophoretic displays, such as those described in U.S. Patent No. 6,241,921; U.S. Patent Application Publication No. 2015 / 0277160; and U.S. Patent Application Publications Nos. 2015 / 0005720 and 2016 / 0012710.

[0053] 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 if no discrete capsule membrane is 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.

[0054] 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 rather retained within multiple cavities formed within a carrier medium, typically a polymer membrane. See, for example, U.S. Patents 6,672,921 and 6,788,449.

[0055] Although electrophoretic media are typically opaque (because, for example, in many electrophoretic media, particles essentially block the transmission of visible light through the display) and operate in a reflective mode, many electrophoretic displays can be manufactured to operate in a so-called shutter mode, where one display state is essentially opaque and the other is translucent. See, for example, U.S. Patents 5,872,552; 6,130,774; 6,144,361; 6,172,798; 6,271,823; 6,225,971; and 6,184,856. Dielectric electrophoretic displays are similar to electrophoretic displays but rely on changes in electric field strength and can operate in a similar mode. See U.S. Patent 4,418,346. Other types of electro-optic displays may also be able to operate in shutter mode. Electro-optic media operating in shutter mode can be used in multilayer structures of full-color displays; in such structures, at least one layer adjacent to the display's viewing surface operates in shutter mode to expose or conceal a second layer further away from the viewing surface.

[0056] Encapsulated electrophoretic displays generally 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 "print" is intended to include, but is not limited to, all of the following forms of printing and coating: pre-quantity coating such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coating such as roller blade coating, forward and reverse roller 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. 7,339,715); and other similar techniques.) Therefore, the resulting display can be flexible. Furthermore, because the display medium can be printed (using various methods), the display itself can be manufactured inexpensively.

[0057] As described above, most simple prior art 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 different second 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 a first type and a second type of electrophoretic particles with different first and second colors in an uncolored 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 desired, a color filter array (CFA) can be placed on the viewing surface of a monochrome (black and white) display. (For example, U.S. Patent No. 6,862,128 discloses an electrophoretic display with a CFA.) Displays with CFAs rely on area sharing and color mixing to create color stimuli. The available display area is shared among 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 (2×2) 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 colorants are always present, and colors can only be modulated by switching the corresponding pixel of the underlying monochrome display to white or black (turning the corresponding primary color on or off). For example, in an ideal RGBW display, each of the red, green, blue, and white primary colors occupies a quarter of the display area (one of the four subpixels), the white subpixel is as bright as the white of the underlying monochrome display, and each colored subpixel is no less than one-third the size of the white of the monochrome display. The overall white brightness displayed on a monitor cannot exceed half the brightness of a white subpixel (the white area of ​​a monitor is produced by displaying one white subpixel out of every four white subpixels, plus each colored subpixel in its colored form is equivalent to one-third of a white subpixel, so the combined contribution of three colored subpixels does not exceed that of one white subpixel). Color brightness and saturation are reduced by sharing areas with colored pixels switched to black. Area sharing is particularly problematic when mixing yellow, as it is lighter than any other color of equal brightness, and saturated yellow is almost as bright as white. Switching blue pixels (one-quarter of the display area) to black makes yellow too dark.

[0058] U.S. Patents 8,576,476 and 8,797,634 describe multicolor electrophoretic displays 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 patents are capable of displaying any primary color (red, green, blue, cyan, magenta, yellow, white, and black) at any pixel location. However, the use of multiple electrophoretic layers 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 at the same voltage. Furthermore, optical losses in the electrophoretic layer closest to the observation surface (e.g., due to light scattering or unwanted light absorption) can affect the appearance of the image formed in the underlying electrophoretic layer.

[0059] Two other types of electrophoretic systems provide a single electrophoretic medium capable of displaying any color at any pixel location. Specifically, U.S. Patent No. 9,697,778 describes a display in which a dyeing solvent binds to white (light-scattering) particles that move in a first direction when a low voltage is applied and in the opposite direction when a higher voltage is applied. A full-color display can be achieved when the white particles and the dyeing solvent bind to two additional particles with opposite charges to the white particles. However, the color states of the '778 patent are unacceptable for applications such as text readers. In particular, some of the dyeing fluid will always separate the white scattering particles from the viewing surface, resulting in a tinted white state of the display.

[0060] A second form of electrophoretic medium capable of displaying arbitrary colors at any pixel location is described in U.S. Patent No. 9,921,451. In the '451 patent, the electrophoretic medium comprises four particles: white, cyan, magenta, and yellow, two of which are positively charged and two are negatively charged. However, the display of the '451 patent also suffers from color mixing problems with the white state. Because one of the particles has the same charge as the white particle, when a white state is desired, some particles with the same charge move toward the viewing surface along with the white particle. While complex waveforms can be driven into the display to overcome this unwanted hue, such waveforms significantly increase the display's refresh rate and, in some instances, cause unacceptable "flickering" between images.

[0061] Figure 1 This is a simplified diagram (not to scale) illustrating an example of a prior art electrophoretic display as disclosed in U.S. Patent No. 10,324,577. The display 100 includes an electrophoretic material layer 130 and at least two other layers 110 and 120 disposed on opposite sides of the electrophoretic material 130, at least one of which is an electrode layer, such as… Figure 1Layer 110 is shown in the diagram. The front electrode 110 may represent the viewing side of the display 100; in this case, the front electrode 110 may be a transparent conductor, such as indium tin oxide (ITO) (in some cases, it may be deposited on a transparent substrate, such as polyethylene terephthalate (PET)). The display 100 also includes a backplane 150, which includes a plurality of driving electrodes 153 and a substrate layer 157. The electrophoretic material layer 130 may include microcapsules 133 holding electrophoretic pigment particles 135 and 137 and a solvent, wherein the microcapsules 133 are dispersed in a polymer binder 139. Nevertheless, it should be understood that the electrophoretic medium (particles 135 and 137 and solvent) may be enclosed in microcells (microcups) or distributed in a polymer without surrounding microcapsules. Typically, the pigment particles 137 and 135 are controlled (displaced) by an electric field generated between the front electrode 110 and the pixel electrodes 153. In many conventional electrophoretic displays, electrically driven waveforms are transmitted to pixel electrodes 153 via conductive traces (not shown) that are coupled to thin-film transistors (TFTs), allowing the pixel electrodes to be addressed using a row-column addressing scheme. In some embodiments, the front electrode 110 is simply grounded and the image is driven by providing positive and negative potentials to the pixel electrodes 153, which are individually addressable. In other embodiments, a potential may also be applied to the front electrode 110 to provide a larger field variation between the front electrode and the pixel electrodes 153.

[0062] In many embodiments, the TFT array forms an active matrix 160 for image driving, such as Figure 2 As shown. For example, each pixel electrode 161 (corresponding to Figure 1 153) is coupled to a patterned array of thin-film transistors 162 and connected to a gate (row) driver line 164 and a source (column) driver line 106, extending perpendicularly to the gate driver line 164. Similarly, typically, a common (top) transparent electrode 163 (corresponding to...) Figure 1110) has the form of a single continuous electrode, while another electrode or electrode layer is patterned into a matrix of pixel electrodes 161, each pixel electrode 161 defining a pixel of the display. An electrophoretic medium 100 may be disposed between the pixel electrodes 161 and the common electrode 163. Any of the electrophoretic media described above may be used. A source driver (not shown) is connected to source driver line 106 and provides a source voltage to all TFTs 162 in a column to be addressed. A gate driver (not shown) is connected to gate driver line 164 to provide a bias voltage that will turn on (or off) the gate of each TFT 162 along that row. The gate scan rate is typically approximately 60-150 Hz. When the TFT 162 is n-type, making the gate-source voltage positive allows the source voltage to be short-circuited to the drain. Making the gate negative relative to the source causes the drain-source current to drop, and the drain is effectively floated. Because the scan drivers operate sequentially, there is typically some measurable delay in the update time between the top and bottom row electrodes. It should be understood that the allocation of "row" and "column" electrodes is somewhat arbitrary, and TFT arrays with interchangeable row and column electrode roles can be fabricated. Each pixel of the active matrix 160 also includes a storage capacitor 165. The storage capacitor 165 is typically coupled to a Vcom line 166. In some embodiments, a common light-transmitting electrode 163 is coupled to ground, such as... Figure 2 As shown. In other embodiments, the common transparent electrode 163 is also coupled to the Vcom line 166 (as shown). Figure 2 (Not shown in the image).

[0063] Although electrophoretic display media are described as “black / white,” they are typically driven to multiple different states between black and white to achieve various hues or “grayscales.” Furthermore, a given pixel can be driven between first and second grayscale states (which include the endpoints of white and black) by driving the pixel through a transition from an initial grayscale level to a final grayscale level (which may be the same as or different from the initial grayscale level). The term “waveform” will be used to refer to the entire voltage-time curve used to achieve a transition from a particular initial grayscale level to a particular final grayscale level. Typically, such a waveform will include multiple waveform elements; where these elements are substantially rectangular (i.e., where a given element includes the application of a constant voltage over a period of time), these elements may be referred to as “pulses” or “drive pulses.” The term “drive scheme” refers to a set of waveforms sufficient to achieve all possible transitions between grayscale levels for a particular display. A display can use more than one drive scheme; for example, as taught in the aforementioned U.S. Patent No. 7,012,600, the drive scheme may need to be modified according to parameters such as the temperature of the display or the operating time during its lifetime, and therefore multiple different drive schemes can be provided for the display to be used at different temperatures, etc. A set of driver schemes used in this way can be called a "set of related driver schemes". It is also possible to use more than one driver scheme simultaneously in different areas of the same display. A set of driver schemes used in this way can be called a "set of simultaneous driver schemes".

[0064] The fabrication of three-layer electrophoretic displays typically involves at least one lamination operation. For example, several of the aforementioned patents and applications describe a process for manufacturing encapsulated electrophoretic displays, wherein an encapsulated electrophoretic medium containing a capsule in an adhesive is coated onto a flexible substrate comprising an indium tin oxide (ITO) or similar conductive coating on a plastic film (which serves as an electrode in the final display), and the capsule / adhesive coating is dried to form a coherent layer of electrophoretic medium firmly adhered to the substrate. Separately, a backplate is prepared (see...). Figure 1 It includes a pixel electrode array and a method for connecting the pixel electrodes to a driving circuit (see...). Figure 2 The appropriate conductor arrangement is required. To form the final display, a substrate with a capsule / adhesive layer is laminated to a backsheet using a laminating adhesive. Where additional non-transparent layers (such as a digital sensor layer (Wacom Technologies, Portland, OR)) are desired, these layers are typically inserted beneath the electrophoretic display layer. The backsheet can be flexible or mounted on glass and is typically fabricated using multilayer photolithographic patterning. A so-called "front-plane laminate" comprising the electrophoretic composition is laminated to the backsheet using a conductive adhesive layer.

[0065] Figure 3A and 3BThe figures shown are a simplified cross-sectional view and a plan view illustrating the basic design of an exemplary prior art projected capacitive touch sensor 172. Such a projected capacitive touch sensor, and the controller chip for processing touch input, are commercially available from various sources, including, for example, Zytronic, 3M, Densitron, and Elo Touch Solutions.

[0066] The touch sensor 172 has an array structure including multiple row and column electrodes 176 and 178 separated by a dielectric layer 174. This array structure typically covers the entire viewing surface of the display.

[0067] For emissive displays, the light absorption of layers 176 and 178 contributes negligibly to the display's appearance. However, this is not the case for electrophoretic and other reflective displays, where any absorption of light before it reaches the electrophoretic display surface degrades image quality, particularly in the white (reflective) state. It is not uncommon for touch sensors, including transparent electrodes made of indium tin oxide (ITO), to experience a loss of 5-10 L* in the white state of an electrophoretic display.

[0068] Figure 3B The electrode patterns shown are typically used in relatively non-conductive materials such as ITO. As illustrated, the combination of two arrays of sensing electrodes essentially covers the entire area of ​​the display. Although the ITO pattern can be made on a single, diamond-shaped plane connected by “bridges” (which are separated from the plane of the electrodes by insulators), the ITO pattern will still cover most of the display surface, leading to optical degradation.

[0069] Cable meshes made of materials with higher conductivity than ITO (such as copper or silver) have lower conductor area coverage and therefore lower optical degradation of the displayed image from the touch sensor. However, even sparse meshes made of these materials can absorb about 5-10% of the incident light. Therefore, it is desirable to reduce the interface between light-absorbing conductive materials and layers in the display module (which would cause Fresnel loss if their refractive indices do not match).

[0070] Figure 4This is a cross-sectional view of a prior art display module 200 with a projected capacitive touch sensor. A TFT backplane array 222 is laminated to a front plane, which includes an electrophoretic medium 216 separated by walls 212 defining microcuplets. (In other embodiments, the electrophoretic medium may be separated within microcapsules.) The microcuplets are sealed by a sealing layer 218 and bonded to the backplane 222 using a conductive adhesive layer 220. The electrophoretic medium 216 is addressed using pixel electrodes disposed on the backplane 222 and a transparent common electrode 214 on the opposite side of the medium. Covering the common electrode 214 are multiple layers 210, which typically include a substrate such as polyethylene terephthalate (PET) used in a roll-to-roll process for imprinting the microcuplets, and bonded by an optically transparent adhesive to a protective layer that serves as a moisture and UV barrier.

[0071] Touch sensor electrodes 224 and 226 are located on opposite sides of dielectric film layer 206 and are bonded to the electrophoretic display using optically transparent adhesive layer 208. Above the touch sensor are other layers, such as a light guide plate and a cover lens, collectively shown as 202, which are attached to the touch sensor using optically transparent adhesive layer 204. The order of the layers above the electrophoretic medium may differ from the figures shown.

[0072] like Figure 4 As shown, there are three light-absorbing conductive layers 214, 224, and 226 on the electrophoretic material 216. Additional conductive layers may also be included, such as a shielding layer to protect the touch sensor from noise caused by switching displays.

[0073] Figure 5 A touch-enabled display device 300 according to one or more embodiments of the present invention is shown. Figure 4 Similar to device 200, device 300 includes a TFT backplane array 222 laminated to a front plane, the front plane including an electrophoretic dielectric 216 separated by walls 212 defining microcuplets. The microcuplets are sealed by a sealing layer 218 and bonded to the backplane 222 using a conductive adhesive layer 220.

[0074] The display device 300 also includes a projected capacitive touch sensor, which includes touch sensor electrodes 224 and 226 on opposite sides of the dielectric layer 206, similar to... Figure 4 Touch sensor. Figure 5 The display device 300 and Figure 4The difference between device 200 and device 200 is that there is no transparent electrode 214 for addressing the electrophoretic medium 216, and its function is instead performed by electrode 226 (also used for a touch sensor) and one or more semiconductive (e.g., ion-conductive) layers 308 embedded therein. As used herein, the term “semiconductive” refers to conductivity that is high enough to present a sufficiently uniform image over the entire area of ​​the display, but low enough to allow touch sensing, as described in further detail below. Therefore, the electrophoretic medium 216 is addressed using a combination of (a) pixelated electrodes on the backplane 222 and (b) an electrode grid 226 serving as a common electrode with one or more semiconductive layers 308.

[0075] Electrodes 224 and 226 can be patterned according to methods known in the art, such as photolithography or printing with conductive ink.

[0076] This arrangement improves optical performance by eliminating one of the light-absorbing electrode layers in prior art modules from the stack covering the electrophoretic medium. The absence of the electrode layer presents two problems that need to be addressed. First, it is impossible to simultaneously address the display 300 and sense touch, as a single electrode array 226 serves both purposes. According to one or more embodiments, addressing the display and sensing touch are achieved by dividing the frame time of refreshing the display into two time segments: a first duration during which the backplane is scanned and an addressing voltage is provided to the storage capacitors on the display backplane; and a second duration during which touch sensing is performed. Sensing does not need to occur in every frame of the display refresh, although this is preferred. Typically, sensing will increase the time required for the display to refresh a single frame by approximately 20%. The display does not turn off during the touch sensing time, so all pixels maintain their voltage levels. The electrode has a dual function, so a common electrode voltage is superimposed on the touch sensing signal. This is possible because the common electrode voltage is typically DC, while the touch sensing signal is typically low-voltage AC. Therefore, during the addressing line, the electrode only has the common electrode signal, while during the touch sensing cycle, the AC sensing signal is superimposed.

[0077] When the display is not addressed, the touch sensor can continuously record events, and users typically do not interact with the display when it refreshes.

[0078] The second problem that needs to be addressed due to the lack of an electrode layer is that the electrodes 226 may be too widely spaced to uniformly address the electrophoretic material. To mitigate this problem, the semiconductive layer 308 embedded in the electrodes 226 is made to have sufficient conductivity to allow halos over the gap regions between adjacent electrodes 326. This conductivity can be achieved, for example, by providing ionic conductivity in layer 308 in a manner known in the art, such as by including ionic dopants in the polymer matrix. The conductivity should be increased without causing additional light absorption. Preferably, layer 308 has a thickness ranging from about 2 to 50 micrometers and a depth of about 10 μm. 3 -10 7 The resistivity range is Ω·cm. A particularly preferred thickness is in the range of 5-25 micrometers. If the conductivity of layer 308 is insufficient, the pattern of electrode 326 may be visible in image areas intended to have constant optical density. However, if the conductivity is too high, the spatial resolution of touch sensing will be reduced. U.S. Patent No. 10,151,955 describes various polymeric materials that can be used to manufacture layer 308. Furthermore, various polymeric electrolytes have been developed for non-display applications. See, for example, J. Mater. Chem. A, 2017, 5, 11152-11162.

[0079] Doped polymeric materials that can be used in semiconductor polymeric material layers include, but are not limited to, aliphatic or aromatic polyurethane latexes, polyacrylates, and poly(meth)acrylates containing dopants, such as tetrabutylammonium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, polyvinyl alcohol, ion-modified polyvinyl alcohol, gelatin, polyvinylpyrrolidone, and combinations thereof. Polymer blends containing aromatic isocyanates are less preferred. Examples of formulations that can be included in semiconductive polymeric material layers are described in U.S. Patent Application Publication No. 2017 / 0088758 and U.S. Patents Nos. 7,012,735; 7,173,752; and 9,777,201.

[0080] The display module 300 according to one or more embodiments can be as follows: Figures 6A-6E The fabrication shown illustrates the use of microcup-separated electrophoretic layers, although similar structures can be fabricated using microcapsules.

[0081] In step (i), as Figure 6A As shown, the microcup 212 is embossed onto the bottom layer 314 disposed on the substrate 402. The substrate 402 has a release coating that allows it to be peeled off from the layer 314.

[0082] In step (ii), as Figure 6B As shown, the microcup is filled with electrophoretic fluid 216 and sealed with polymer composition 218, as is known in the art.

[0083] In step (iii), as Figure 6C As shown, the adhesive layer 320 coated on the substrate 404 having a release layer is laminated onto the sealing layer 218 of the structure made in step (ii). The peel force required to remove the substrate 404 from the sealing layer 218 is less than the force required to separate the substrate 402 from the bottom layer 314.

[0084] In step (iv), as Figure 6D As shown, the substrate 404 is removed and the adhesive layer 220 is laminated onto the pixelated backplate 222, which may be segmented or an active matrix.

[0085] In step (v), as Figure 6E As shown, substrate 402 is removed from the structure created in step (iv), and substrate 206 containing electrode arrays 224 and 226 is laminated onto bottom layer 314 using a conductive, optically transparent layer (or multiple layers) 308. Layer 308 itself may have been coated on a release substrate, laminated onto the touch assembly or bottom layer 314, after which the substrate is removed and a second lamination is performed. Additional layers (such as a light guide plate and cover lens 202) can then be applied to the touch sensor having an optically transparent adhesive layer 204.

[0086] It will be apparent to those skilled in the art that many changes and modifications can be made to the specific embodiments of the present invention described above without departing from the scope of the invention. Therefore, all the above descriptions should be interpreted as illustrative rather than restrictive.

Claims

1. An electro-optical display device with touch functionality, comprising multiple stacked layers, wherein the layers are, in sequence: The first electrode layer at the viewing surface of the touch screen electro-optical display device; Dielectric layer; Second electrode layer; Semiconducting layer; Electro-optic dielectric layer; as well as Third electrode layer; The second electrode layer, the semiconductive layer, the electro-optic dielectric layer, and the third electrode layer form an electro-optic device, wherein the electro-optic dielectric layer is addressed by applying a driving voltage to the third electrode layer while maintaining a constant voltage on the second electrode layer; and The first electrode layer, the dielectric layer, and the second electrode layer form a capacitive touch sensor, which detects touch input by sensing the capacitance change at the touch point on the first electrode layer.

2. The apparatus according to claim 1, wherein, The first electrode layer and the second electrode layer include a plurality of electrodes forming a row and column grid.

3. The apparatus according to claim 2, wherein, The plurality of electrodes of the second electrode layer are disposed in the semiconductive layer, which is configured to promote a halo effect in the gap between the electrodes.

4. The apparatus according to any one of the preceding claims, wherein, The semiconducting layer includes an ion-conducting layer.

5. The apparatus according to claim 4, wherein, The ion-conducting layer comprises a polymer material containing ion dopants.

6. The apparatus according to any one of the preceding claims, wherein, The semiconductive layer has a thickness of approximately 2 to 50 micrometers and / or a resistivity of approximately 10³ to 10⁷ Ω⋅cm.

7. The apparatus according to any one of the preceding claims, wherein, The semiconductive layer has a thickness of approximately 5 to 25 micrometers.

8. The apparatus according to any one of the preceding claims, wherein, The electro-optical device and the capacitive touch sensor operate at different times.

9. The apparatus according to any one of the preceding claims, wherein, Each time frame used to refresh the electro-optical device includes a first time portion for addressing the optical medium layer and a separate second time portion for detecting touch input.

10. The apparatus according to any one of the preceding claims further includes a light guide plate and a cover lens on the side of the first electrode layer opposite to the dielectric layer.

11. The apparatus according to any one of the preceding claims, wherein, The third electrode layer includes a pixel electrode array in the backplane.

12. The apparatus according to any one of the preceding claims, wherein, The electro-optic medium comprises charged pigment particles dispersed in a nonpolar solvent.

13. The apparatus according to any one of the preceding claims, wherein, The electro-optic dielectric layer includes an encapsulated electrophoretic dielectric.

14. The apparatus according to claim 13, wherein, The encapsulated electrophoretic medium includes electrophoretic media encapsulated in microcapsules or microcups.

15. The apparatus according to any one of the preceding claims, wherein, The electro-optic medium is bistable.

16. The apparatus according to any one of the preceding claims, wherein, The first electrode layer, the second electrode layer, or the third electrode layer comprises (a) a material selected from the group consisting of aluminosilicate, indium tin oxide, poly(3,4-ethylenedioxythiophene) and combinations thereof, (b) an organic material, (c) a composite material, or (d) a sparse mesh.

17. The apparatus according to any one of the preceding claims, wherein, The device does not contain indium tin oxide.

18. The apparatus according to any one of the preceding claims, wherein, The first electrode layer and the second electrode layer are transparent to light.

19. A method for manufacturing a touchscreen electro-optical display device, comprising the following steps: (a) Provide an electro-optic dielectric layer; (b) Laminating one side of the electro-optic dielectric layer onto the pixelated backplane; as well as (c) Laminating the opposite sides of the electro-optic dielectric layer onto a layered structure, the layered structure including a first electrode layer, a second electrode layer, and a dielectric layer between the first electrode layer and the second electrode layer, wherein the second electrode layer is adjacent to the electro-optic dielectric layer, and the first electrode layer is located at the viewing surface of the touch screen electro-optic display device, wherein the first electrode layer and the second electrode layer include a plurality of electrodes forming a row and column grid, and wherein the plurality of electrodes of the second electrode layer are disposed in a semiconductive layer configured to promote halos in the gaps between the electrodes.

20. A method for manufacturing a touchscreen electro-optical display device, comprising the following steps: (a) Provide an electro-optic dielectric layer; (b) Laminating one side of the electro-optic dielectric layer onto a layered structure, the layered structure including a first electrode layer, a second electrode layer, and a dielectric layer between the first electrode layer and the second electrode layer, wherein the second electrode layer is adjacent to the electro-optic dielectric layer, and the first electrode layer is located at the viewing surface of the touchscreen electro-optic display device, wherein the first electrode layer and the second electrode layer include a plurality of electrodes forming a row and column grid, and wherein the plurality of electrodes of the second electrode layer are disposed in a semiconductive layer configured to promote halos in the gaps between the electrodes; and (c) Laminating the opposite sides of the electro-optic dielectric layer onto the pixelated backing.

21. The method according to any one of the preceding claims, wherein, Step (a) includes encapsulating an electrophoretic medium in microcapsules and distributing the microcapsules in an adhesive to form a slurry for coating onto the pixelated backplate or the layered structure.

22. The method according to claim 19 or 20, wherein, Step (a) includes: (i) Imprinting microcuplets on a sublayer disposed on a substrate; (ii) Filling the microcup with electrophoretic fluid; and (iii) Seal the microcup with a polymer sealing layer.

23. The method according to claim 22, wherein, Laminating the electro-optic dielectric layer onto the layered structure includes laminating the bottom layer of the electro-optic dielectric layer onto the second electrode layer of the layered structure.

24. The method according to any one of the preceding claims, wherein, Laminating the electro-optic dielectric layer onto the pixelated backplane includes: (i) Pressing the substrate layer coated with the adhesive layer onto the polymer sealing layer of the electro-optic dielectric layer; (ii) Remove the substrate; and (iii) Laminating the pixelated backsheet onto the adhesive layer.

25. The method according to any one of the preceding claims, wherein, The semiconductor layer includes an ion-conducting layer.

26. The method of claim 25, wherein, The ion-conducting layer comprises a polymer material containing ion dopants.

27. The method according to any one of the preceding claims, wherein, The semiconductive layer has a thickness of approximately 2 to 50 micrometers and / or a resistivity of approximately 10³ to 10⁷ Ω⋅cm.

28. The method according to any one of the preceding claims, wherein, The semiconductive layer has a thickness of approximately 5 to 25 micrometers.

29. The method according to any one of the preceding claims further includes attaching a light guide plate and a cover lens to the side of the first electrode layer opposite to the dielectric layer.

30. The method according to any one of the preceding claims, wherein, The electro-optic medium comprises charged pigment particles dispersed in a nonpolar solvent.

31. The method according to any one of the preceding claims, wherein, The electro-optic dielectric layer includes an encapsulated electrophoretic dielectric.

32. The method according to any one of the preceding claims, wherein, The electro-optic medium is bistable.

33. The method according to any one of the preceding claims, wherein, The device does not contain indium tin oxide.

34. The method according to any one of the preceding claims, wherein, The first electrode layer and the second electrode layer are transparent to light.

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