Foldable electro-optical display with digitization and touch sensing

Abstract

An electro-optic display is flexible and can be folded in a book-like manner. The display device may include a flexible display and a bending mechanism for allowing the flexible display to be in a closed state. Portions of the flexible electro-optic display may be connected to areas of a planar support member so that when the display is in an open state, the display is flat and smooth. In further embodiments, the electro-optic display may include a touch sensing or digitizing layer to record interactions with a stylus.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application number 201880030561.2 and title “Foldable electro-optical display with digitalization and touch sensing”.

[0002] Incorporation by reference to any priority application

[0003] This application claims priority to U.S. Provisional Application No. 62 / 508,502 filed on May 19, 2017 and U.S. Provisional Application No. 62 / 614,487 filed on January 7, 2018. The entire contents of the priority applications and other patents and applications listed herein are incorporated herein by reference. Technical Field

[0004] The present invention relates to reflective electro-optical display devices and materials for such displays. More specifically, the present invention relates to flexible electro-optical displays that can be folded in a manner like a book. In some embodiments, the foldable device senses touch. In some embodiments, the foldable device can track the position of a stylus used to write on the device. Background Art

[0005] The present invention relates to backplanes for electro-optical displays and methods for the formation of such backplanes. The backplanes of the present invention are particularly, but not exclusively, intended for use with particle-based electrophoretic displays, in which one or more types of charged particles are suspended in a liquid and move in the liquid under the influence of an electric field to alter the appearance of the display.

[0006] In some cases, flexible displays can be folded so as to be portable and / or conveniently stored. If the display is simply folded like a book, it may be folded at a radius of curvature that is smaller than the minimum radius of curvature designed to prevent the display from breaking. To prevent such problems, various mechanisms have been implemented on the curved portion of the display, such as hinges and / or other structures. For example, Polymer Vision has disclosed a product, Readius TM , which uses one or more mechanical hinge mechanisms to facilitate folding of the flexible display.

[0007] In another example, Japanese Patent Early Publication No. 2014-161009 discloses a flexible mobile terminal device configured to be bent at various angles. It is proposed that the terminal device includes a folding portion for bending the device to the front surface or the upper rear position of the terminal device body. The flexible display mounted on the upper part of the terminal device body can be bent to the front surface or the rear surface according to the bending direction of the folding portion. The device further includes a sliding portion for sliding one end of the flexible display by the difference between the degree of compression / tension generated by the difference in elongation between the folding portion and the flexible display during the bending of the folding portion.

[0008] Both of the above examples result in a thick and heavy product. Readius by Polymer Vision TM A mechanical hinge mechanism with a complex structure and a bulky shape is adopted. The device of Japanese Patent Early Publication No. 2014-161009 has a bellows shape and the sliding part needs to be adjusted manually, and the device is also complex and bulky.

[0009] Another limitation of prior art book-like flexible electro-optical displays is that after repeated opening and closing, a portion of the flexible electro-optical display may not assume a flat position. In particular, the folded area may become "wrinkled", making it difficult to read on the curved portion. In other devices that allow the flexible display to "float" so that it can move relative to the frame, the display may not be completely flat, or worse, it may move while the user is reading. The present invention solves many of these problems and provides a flexible, thin and lightweight foldable electro-optical display that can be folded in a book-like manner. Summary of the invention

[0010] The present invention provides an image display device with a flexible electro-optical display. The flexible electro-optical display may include a bendable portion, which is flexible and configured to display an image, however, a portion of the flexible electro-optical display may not be bendable. Specifically, the image display device of the present application includes an image display device, which includes a flexible electro-optical display, which includes two planar portions and a bendable portion. The bendable portion is flexible and can display an image. Each planar support member includes a fixed area and an unfixed area. The fixed area is connected to and supports one of the planar portions of the flexible electro-optical display, while the unfixed area is not connected to the flexible electro-optical display. The image display device includes a bending mechanism, which includes two separate rotation axes, which are parallel to a center line defined by the flexible electro-optical display. Each of the two axes is arranged to be separated from the center line by a predetermined distance, and each of the axes defines a pivot of one of the planar support members. Each pivot is adjacent to the boundary between the fixed area and the unfixed area of ​​the planar support member. The disclosed design protects the flexible electro-optical display from excessive bending (having a small radius of curvature), thereby preventing breakage. Because most of the flexible electro-optical display is fixed on a planar support member, the entire display exhibits high flatness in the open state and also stably maintains the open state.

[0011] In some embodiments, the flexible electro-optic display includes an electrophoretic medium, which may optionally be encapsulated or distributed in a plurality of microcells.

[0012] In some embodiments, the flexible electro-optical display is bonded to the planar support member in the fixed area, for example, with an adhesive. In some embodiments, one of the two separate rotating shafts includes a rotating gear at the proximal end, and the bending mechanism further includes a rotation synchronizer for synchronously rotating the rotating gear. The rotation synchronizer may include two synchronous gears, wherein each of the synchronous gears is meshed with another synchronous gear and one of the rotating gears. In some embodiments, the bending mechanism includes an empty volume that exceeds the volume swept by the unfixed areas of the two planar support members rotating around their respective axes.

[0013] In some embodiments, the planar support member is substantially rectangular. If the length "ζ" is defined as the distance between the axes, and "R" is the minimum radius of curvature for operating the flexible electro-optical display, then the relationship between "ζ" and "R" is ζ>2*R. If the distance "a" is defined as the distance from the axis to the nearest edge of the fixed area, and "R" is the minimum radius of curvature for operating the flexible electro-optical display, then the relationship between "a" and "R" is a>π*R. Of course, ζ and a may be larger, typically 2a>ζ.

[0014] In some embodiments, the flexible electro-optical display includes a flexible backplane including an array of pixels. Some flexible backplanes will include at least 100 pixels per 2.5 cm linear distance across the backplane. The flexible backplane may include thin film transistors composed of a doped polymer. The flexible backplane may include flexible traces made of a conductive polymer or a polymer containing a conductive material (e.g., a metal, nanoparticles, nanowires, nanotubes, graphite, or graphene).

[0015] In some embodiments, a portion of the flexible electro-optical display is configured to slide freely against a support member or digitizing layer, thereby facilitating smooth closure of the device and preventing wrinkling of the flexible display after repeated folding actions.

[0016] In some embodiments, the foldable display device includes a digitization layer that allows the position of the stylus to be tracked and "writing" to be achieved on the device. In some embodiments, the foldable display device includes a touch sensor that can be used to detect the presence of, for example, a user's finger. When the device is folded, touch sensing can be provided by synchronizing the position of the touch sensors when the device is closed or by using different touch sensors that sense different wavelengths of light. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a general description of the electrophoretic media applicable to the present invention;

[0018] Figure 2 is a general description of a flexible thin film transistor (TFT) array suitable for use with the present invention;

[0019] Figure 3A An embodiment of the present invention is shown in an open state;

[0020] Figure 3B An embodiment of the present invention is shown in a closed state;

[0021] Figure 4A is a detailed view of a rotary synchronizer including a synchronous gear and a rotary gear connected to a shaft about which a planar support member rotates;

[0022] Figure 4B is a detailed view of the rotary synchronizer covered by the end cover;

[0023] Figure 5A is an end view of an embodiment of an image display device showing more details of the bending mechanism;

[0024] Figure 5Bis a top view of an embodiment of an image display device showing a displacement "ζ" between two axes and an unfixed area where the flexible electrophoretic display is not connected to a planar support member;

[0025] Figure 5C showing the flexible electro-optical display removed from the image display device;

[0026] Figure 5D showing staggered planar support members in an open or flat position;

[0027] Fig. 6A is an end view of an embodiment of an image display device showing a planar support member in a fully open state;

[0028] Figure 6B is an end view of an embodiment of an image display device showing a planar support member in a half-open state;

[0029] Figure 6C is an end view of an embodiment of an image display device showing a planar support member in a nearly closed ("folded") state;

[0030] Fig.6D is an end view of an embodiment of an image display device showing a planar support member in a fully closed ("folded") position;

[0031] Figure 7 is a cross-sectional view of an embodiment of the present invention showing the different layers of the device and an unsecured area near a bent area of ​​a flexible display;

[0032] Fig. 8A Shows undesired backward bending (stretching) of a flexible display;

[0033] Figure 8B An unfixed area is shown with supplemental support to reduce the likelihood of posterior bending;

[0034] Fig.9A showing an auxiliary support region including an extended adhesive region;

[0035] Fig. 9B An auxiliary support area is shown, which is an extension of the shape of the core plate;

[0036] Fig. 10A Shows undesired backward bending (stretching) of a flexible display;

[0037] Fig. 10B Shows a low slope of extension used when some back bending (stretching) is unavoidable, e.g. due to thickness limitations;

[0038] Fig.11AAlternative adhesive layers for use in the device of the present invention are shown;

[0039] Fig. 11B Alternative adhesive layers for use in the device of the present invention are shown;

[0040] Fig.12 A foldable and writable display is shown;

[0041] Fig.13 is an exploded view of a foldable and writable display;

[0042] Fig.14 is a cross-sectional view of a foldable writable display, the foldable writable display comprising a flexible display layer that is not secured to an underlying digitizing layer;

[0043] Fig.15A is a cross-sectional view showing layers of a foldable writable display;

[0044] Fig. 15B yes Fig.15A an exploded view of a corner portion of the device showing details of the flexible display layer and the side strip structure that holds the flexible display layer in close proximity to the digitizing layer while allowing them to move relative to each other when the device is moved between open and closed states;

[0045] Fig.16 Details of the synchronous gears that coordinate the smooth opening and closing of the core board that supports the digitization layer and the flexible display layer;

[0046] Fig.17 A cross-section showing the layers of a foldable and writable display including a pressurizing mechanism for assisting in folding;

[0047] Fig.18 is an end view of a foldable writable display including a pressurizing mechanism;

[0048] Fig.19 is an exploded view of a foldable, writable display including touch sensing;

[0049] Fig. 20 is a cross-section of a foldable, writable display including touch sensing, showing the integration of a touch sensor unit;

[0050] Fig.21 illustrates the operation of a touch sensor that uses infrared light to sense touch location;

[0051] Fig.22A Displays the range of touch sensing using parallel light sources;

[0052] Fig. 22B Shows the range of touch sensing using a light source having an emission angle θ;

[0053] Fig.23 A folding process in a foldable display having a touch sensor unit that rotates as the device is folded is shown. When the device is folded, the touch sensor rotates upward to increase the coverage of the flexible display layer;

[0054] Fig.24 An alternative design for sensing touch on separate portions of a foldable display device is shown. DETAILED DESCRIPTION

[0055] As described above, the present invention provides an electro-optical display that is flexible and can be folded in a book-like manner. The display device may include a flexible display and a bending mechanism for allowing the flexible display in a closed state. Due to the advanced design of the bending mechanism, a portion of the flexible electro-optical display can be connected to an area of ​​a planar support member so that when the display is in an open state, the display unfolds flatly and smoothly.

[0056] The present invention can be used with a variety of electro-optical materials, for example, liquid crystal displays, light-emitting displays (including OLEDS), and cholesteric liquid crystal displays. The present invention is well suited for use with electrophoretic media of the type developed by E Ink Corporation (Billerica, Mass.) and described in the patents and patent publications listed below. Capsule-type electrophoretic media include a plurality of small capsules, each capsule itself including an inner phase containing electrophoretically mobile particles in a fluid medium and a capsule wall surrounding the inner phase. Typically, the capsules themselves are held in a polymeric binder to form a coherent layer located between two electrodes. In a microcell electrophoretic display, the charged particles and fluid are not encapsulated in microcapsules, but are held in a plurality of cavities formed in a carrier medium (usually a polymeric film). The technologies described in these patents and applications include: (a) electrophoretic particles, fluids, and fluid additives; see, e.g., U.S. Patents Nos. 7,002,728 and 7,679,814; (b) capsules, binders, and encapsulation processes; see, e.g., U.S. Patents Nos. 6,922,276 and 7,411,719; (c) microcell structures, wall materials, and methods of forming microcells; see, e.g., U.S. Patents Nos. 7,072,095 and 9,279,906; (d) methods of filling and sealing microcells; see, e.g., U.S. Patents No. 6,922,276 and 7,411,719; 7,144,942 and 7,715,088; (e) films and subassemblies containing electro-optical materials; see, e.g., U.S. Pat. Nos. 6,982,178 and 7,839,564; (f) backplanes, adhesive layers and other auxiliary layers and methods used in displays; see, e.g., 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; 7,30 4,780; 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; 7,535,62 4; 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; 8,79 7,633; 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 Application 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 Patent Nos. 1,099,207 B1 and 1,145,072 B1; (g) color formation and color adjustment; see, e.g., U.S. Patent Nos. 7,075,502 and 7,839,564; and (h) methods for driving displays; see, e.g., U.S. Patent Nos. 7,012,600 and 7,453,445. All patents and patent applications listed herein are incorporated herein by reference in their entirety. Many of the above patents and applications recognize that the walls surrounding discrete microcapsules in a capsule-type electrophoretic medium can be replaced by a continuous phase, thereby producing a so-called polymer dispersed electrophoretic display, wherein the electrophoretic medium comprises a plurality of discrete droplets of electrophoretic fluid and a continuous phase of polymeric material, and that the discrete droplets of electrophoretic fluid within such a polymer dispersed electrophoretic display can be considered to be capsules or microcapsules even though there is no discrete capsule membrane associated with each individual droplet; see, e.g., the aforementioned U.S. Patent No. 6,866,760. Therefore, for the purpose of this application, such polymer dispersed electrophoretic media are considered to be a subspecies of capsule electrophoretic media. ;

[0057] Capsule-type electrophoretic displays generally do not suffer from the clustering and sedimentation failure modes of conventional electrophoretic devices and offer additional advantages, such as the ability to print or coat the displays on a wide variety of flexible and rigid substrates. (The use of the word "printing" is intended to include all forms of printing and coating, including but not limited to: pre-metered coatings (e.g., patch die coating, slot or extrusion coating, slide or cascade coating, and curtain coating); roll coating (e.g., knife over roll coating and 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 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. Furthermore, because the display medium can be printed (using various methods), the display itself can be manufactured inexpensively.

[0058] Although the present invention is primarily directed to electrophoretic media of the type described above and the patents and patent applications listed, other types of electro-optic materials may also be used in the present invention. Alternative electro-optic media are generally reflective in nature, that is, they rely on ambient light for illumination instead of a backlight as found in emissive LCD displays. Alternative electro-optic media include rotating bichromal member type media as described, for example, in U.S. Patents 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. Such displays use a large number of small objects (usually spherical or cylindrical) having two or more portions with different optical properties and an internal dipole. These objects are suspended in liquid-filled bubbles within a substrate, which are filled with liquid so that the objects can rotate freely. The display's presentation is subsequently changed by applying an electric field, thereby rotating the object to various positions and changing which part of the object is visible through the viewing surface. This type of electro-optic medium is usually bistable.

[0059] Another alternative electro-optical display medium is an electrochromic medium, for example, an electrochromic medium in the form of a nanochromic film, which includes an electrode formed at least in part of a semiconductor metal oxide and a plurality of dye molecules attached to the electrode that are capable of reversible color change; 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. This type of nanochromic film is 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 generally bistable.

[0060] Another type of electro-optical display is the electro-wetting display developed by Philips and described in Hayes, RA et al., "Video-Speed ​​Electronic Paper Based on Electrowetting", Nature, 425, 383-385 (2003). US Patent No. 7,420,549 shows that such an electro-wetting display can be made bistable.

[0061] exist Figure 1An exemplary electrophoretic display (EPID) is shown in FIG. The display 100 generally includes an electrophoretic material layer 130 and at least two other layers 110 and 120 arranged on opposite sides of the electrophoretic material 130, at least one of the two layers being an electrode layer, such as Figure 1 The front electrode 110 may represent the viewing side of the display 100, in which case the front electrode 110 may be a transparent conductor such as indium tin oxide (ITO) (which in some cases may be deposited on a transparent substrate such as polyethylene terephthalate (PET)). In the flexible display of the present invention, other flexible conductive materials (e.g., conductive polymers or polymers with conductive additives) may be used for the front electrode. Figure 1 As shown, such an EPID also includes a backplane 150, which includes a plurality of drive electrodes 153 and a substrate layer 157. The electrophoretic material layer 130 may include microcapsules 133, which contain electrophoretic pigment particles 135 and 137 and a solvent, and the microcapsules 133 are dispersed in a polymer binder 139. However, it is understood that the electrophoretic medium (particles 135 and 137 and solvent) can be encapsulated in microcells (microcups) or distributed in a polymer without microcapsules around (for example, the above-mentioned PDEPID design). Typically, the pigment particles 137 and 135 are controlled (displaced) by the electric field generated between the front electrode 110 and the pixel electrode 153. In many conventional EPIDs, the electrical drive waveform is transmitted to the pixel electrode 153 through a conductive trace (not shown) connected to a thin film transistor (TFT), which allows the pixel electrode to be addressed in a row and column addressing method. In some embodiments, the front electrode 110 is only grounded, and the image is driven by providing positive and negative potentials to the pixel electrodes 153 that can be addressed separately. In other embodiments, a potential may also be applied to the front electrode 110 to provide a greater change in the electric field that can be provided between the front electrode and the pixel electrode 153 .

[0062] In many embodiments, such as Figure 2 As shown, the thin film transistor array forms an active matrix for image driving. For example, each pixel electrode ( Figure 1 153) is connected to a thin film transistor 210 which is patterned into an array and connected to an elongated row electrode 220 and an elongated column electrode 230 which extends at right angles to the row electrode 220. In some embodiments, the pixel comprises a transistor made of a metal oxide. In some embodiments, the pixel comprises a transistor formed of a doped polymer. In some embodiments, 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 pixel electrode defining a pixel of the display. Figure 2As shown, the data driver 250 is connected to the column electrode 230 and provides a power supply voltage to all thin film transistors in the column to be addressed. The scan driver 240 is connected to the row electrode 220 to provide a bias voltage that turns on (or turns off) the gate of each thin film transistor along the row. The gate scan rate is usually about 60-100Hz. Making the gate-source voltage positive can cause the source voltage to short-circuit to the drain. Making the gate extremely negative relative to the source can cause the drain-source current to drop and the drain to float effectively. Because the scan driver works in a continuous manner, there is usually some measurable delay in the update time between the top and bottom row electrodes. It is understood that the allocation of "row" and "column" electrodes is somewhat arbitrary, and the thin film transistor array can be manufactured with the row and column electrodes interchanged. In some embodiments, the TFT array is basically flexible, however, individual components such as individual pixel transistors or drive circuits may not be flexible. Flexible traces used to supply voltage to individual pixels may be formed from flexible materials, such as conductive polymers or polymers doped with conductive materials such as metal particles, nanoparticles, nanowires, nanotubes, graphite, and graphene.

[0063] Although EPID media are described as "black / white", they are typically driven to multiple different states between black and white to achieve various tones or "grayscales". In addition, 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 to a final grayscale (which may be different from or the same as the initial grayscale). The term "waveform" will be used to refer to the entire voltage versus time curve used to achieve a transition from a particular initial grayscale to a particular final grayscale. Typically, such a waveform will include multiple waveform components; wherein the components are substantially rectangular (i.e., a given component includes a fixed voltage applied for a period of time); these components 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 grayscales for a particular display. A display may use more than one drive scheme; for example, the aforementioned U.S. Patent No. 7,012,600 teaches that the drive scheme may need to be modified depending on parameters like the temperature of the display or how long it has been operating during its useful life, and thus a display may have multiple different drive schemes for different temperatures, etc. A set of drive schemes used in this manner may be referred to as a "set of related drive schemes." It is also possible to use more than one drive scheme simultaneously in different areas of the same display, and a set of drive schemes used in this manner may be referred to as a "set of simultaneous drive schemes."

[0064] The manufacture of a three-layer electrophoretic display generally involves at least one lamination operation. For example, in some of the above-mentioned patents and applications, a process for manufacturing a capsule-type electrophoretic display is described, in which a capsule-type electrophoretic medium containing capsules in a binder is coated on a similar conductive coating on a flexible substrate or plastic film containing indium tin oxide (ITO) (which serves as one electrode of the final display), and the capsule / binder coating is dried to form an adhesive layer of the electrophoretic medium firmly adhered to the substrate. Separately, a backplane is prepared (see Figure 1 ), which includes a pixel electrode array and a driving circuit that connects the pixel electrodes (see Figure 2 ) is appropriately configured with conductors of the backplane. To form the final display, the substrate with the capsule / adhesive layer thereon is laminated to the backplane using a laminating adhesive. In embodiments where it is desired to have additional layers, such as a digital sensing layer (Wacom Technologies, Portland, Oregon), those layers can be inserted between the electrode layer and the substrate, or an additional substrate can be added between the electrode layer and the additional layer. In a preferred embodiment, the backplane itself is flexible and is prepared by printing pixel electrodes and conductors on a plastic film or other flexible substrate. The lamination technique for mass production of displays by this process is roll lamination using a laminating adhesive.

[0065] During the lamination process, one or more laminating adhesives are used to provide mechanical continuity to the component stack and also to ensure that the layers are relatively flat relative to each other. In some cases, industrial laminating adhesives (lamads) can be used, but the manufacturers of laminating adhesives (of course) devote considerable effort to ensure properties like bond strength and lamination temperature while ignoring the electrical properties of the laminating adhesive. As a result, manufacturers of electrophoretic displays typically modify industrial adhesives to achieve the desired volume resistivity. Methods for modifying the electrical properties of industrial adhesives are described in some of the aforementioned patents. These methods typically involve adding charged copolymers, charged moieties, or conductive particles.

[0066] Figure 3A and Figure 3B 3B is a view showing an electronic book as an example of the image display device of the present application. As shown in the figure, although the folded portion is relatively thick, the electronic book has substantially the same thickness as a general book and its use can have the feeling of carrying a thin book, and by holding it in the hand in a folded state such as shown in FIG. 3B, the electronic book can be carried stably like a general book. In addition, if it is fully opened, it has a Figure 3AThe substantially flat shape shown, but through the invention of the present application, because the flexible display will not bend / break, and even if the e-book is closed, the flatness of the flexible display can be maintained in the open state, and the entire screen can be used without deformation.

[0067] Figure 4A and 4B 1 is a view showing a hinge portion of an example of an image display device of the present application. Figure 4A As shown, the rotating gear 22 is disposed at the proximal end of the rotating shaft 23, and the image display device can be opened and closed in a synchronized manner by engaging the shaft 23 to the synchronization gear 24. Typically, the two rotating gears 22 of the rotating shaft 23 are respectively engaged by two synchronization gears 24, and the two synchronization gears are engaged with each other. With this design, the movement of each of the two planar support members is coordinated to ensure that the flexible electro-optical display moves in a smooth and synchronized manner. Thus, because the front and back covers of the electronic book open and close at the same angle, it is common to open and close the electronic book with one hand. Although in Figure 4A Only one edge side is shown, but the gears are located on both sides of the shaft. Figure 4B As shown, the hinge portion is usually covered by a cover 21 when in use to prevent dirt from entering that might hinder the function of the gear and to prevent the gear from pinching the user's hand. It should be noted that Figure 4A and 4B The rotating gears and synchronous gears shown are exemplary. The gears can be completely circular or they can be part of a circle. Other shapes that provide similar functions can also be used.

[0068] Flexible display bending structure

[0069] Detailed reference for the synchronous bending process Figures 5A-6D is described in more detail. Figure 5A An end view of an image display device including a hinge portion is shown. Figure 5B A top view of the image display device is shown, showing that the rotation axis is offset on both sides of the center line of the flexible electro-optical display. Figures 6A to 6D Shows a change in an end view of the hinge portion when the image display device is bent from an open state to a folded state.

[0070] In general, the image display device includes two planar support members 33 and 36, which are partially fixed to the flexible electro-optical display 31. In some embodiments, the electro-optical display 31 is fixed to the planar support members 33 and 36 by an adhesive layer. In such an embodiment, the planar support members 33 and 36 are rectangular, and the rotation axis 23 is a predetermined distance from the edge 38 of the rectangle and parallel to the center line 39. Of course, as long as the planar support member can support the flexible display, the planar support member is not limited to a rectangle. When each planar support member is rotated along the axis 23 for a maximum of 90°, the rotation axis 23 is a certain distance from the edge 38 of the planar support member, and the area between the axis 23 and the edge 38 is called an unfixed area, which is defined by a boundary 37. Figure 5B As shown, planar support members 33 and 36 each rotate on axis 23. To give the final image display device a more finished appearance, planar support members 33 and 36 are covered with covers 34 and 35, which may be any suitable material, such as plastic, cloth or leather.

[0071] As previously mentioned, there is a minimum radius of curvature "R" that limits the safe bending radius of the flexible electro-optical display. (The location of R is clearly shown in Fig.6D ) Figure 5A As shown, this minimum radius of curvature can be related to the distance between axis 23 (here "ζ") and the distance between axis 23 and boundary 37 (here "a"), where boundary 37 is between the fixed area and the unfixed area on the planar support member. Of course, if the flexible electro-optic display is bent beyond the minimum radius of curvature, then fracture can be expected. If the deflected portion of the flexible electro-optic display is small and the flexible display in a flat state is substantially horizontal, then the unfixed area of ​​the flexible electro-optic display can be considered to be a semicircle with a length from the boundary of one fixed area to the unfixed area to the boundary of the other fixed area. See Fig.6D . Thus, in this minimum configuration, the distance between the axes that allows the curved portion of the flexible electro-optical display to fit between the axes must be at least twice the minimum radius, so ζ>2*R. Of course, in practice, "ζ" should be wider to account for the thickness of the axes and the thickness of the flexible electro-optical display. Therefore, in some embodiments, it is preferred to have ζ>2.5*R or ζ>3*R.

[0072] exist Figure 5B In the example, the range of the unfixed area is easier to see. Figure 5B A top view of the foldable device is shown unfolded. The distance "ζ", i.e. the distance between the axes, and the larger gap between the fixed and unfixed areas on the planar support member can also be Figure 5B Seen in. Figure 5BThe area 15 shown corresponds to the area where the flexible display layer is fixed to the support member (or digitizing layer) in some embodiments. In other embodiments, the entire flexible display layer is fixed to the support member or digitizing layer. In other embodiments, one side of the flexible display layer is fixed to the support member or digitizing layer, while the other side is allowed to move freely on the support member or digitizing layer, but is kept flat by a side strip structure (see below).

[0073] As for the distance between the border between the fixed area and the unfixed area, the circumferential distance around the arc formed by the curved area must be considered. Fig.6D , it is easy to see that the distance along the flexible electro-optical display must be half the circumference or π*R. Assuming that the boundaries 37 are all equidistant from the centerline 39, each "a" must be at least 1 / 2*(π*R-2*R) or a>0.6*R. In practice, it has been found that a>π / 2*R is preferred, and in many embodiments, it is advantageous to have a>π*R.

[0074] In order to account for the movement of the unsecured areas of the planar support members from the axis toward the centerline, a spine 32 is included that has a void volume that exceeds the volume swept by the unsecured areas of the two planar support members rotating about their respective axes. In addition, the spine 32 can be configured to provide additional support to the planar support members when in a closed state. In addition, the length of the additional support portion only needs to be half or more of the distance between the rotation axes, but this is not restrictive and the two planar support members can have different lengths. In this case, it is only necessary that the total length of the additional support portion is not less than the distance between the rotation axes. In addition, as in the planar support members, when in an open state, they can be configured to be alternately connected in a staggered manner in the area between the two axes, such as Figure 5D shown.

[0075] Generally, the flexible display is preferably uniformly adhered to the planar support member as a whole. This is why the touch or visibility of the flexible display changes depending on whether there is an adhesive layer thereon, because it is as thin as paper. Although visibility can be improved, for example, by matting the surface of the flexible display, if the flexible display is touched with a finger or the like, the user is prone to feel the boundary delamination of the adhesive layer. Therefore, the fixed portion of the flexible display is preferably uniformly adhered to the planar support member.

[0076] Figures 6A to 6D It shows how the unfixed curved portions 41-44 of the flexible electro-optical display change when the image display device is manipulated between an open state and a closed state. Fig. 6AThe unsecured portion 41 is shown to be flat in any substantially fully open state, however, in some embodiments, the angle between the planar support members 33 and 36 is approximately 175°. Figure 6B As shown in FIG. 1 , when the planar support members rotate until the angle between the planar support members is 120°, the unfixed portion 42 of the flexible display begins to separate from the unfixed region of the planar support members, thereby forming an arc with a large curvature. Figure 6C In the example, the straight-line distance between the boundary 37 between the fixed area and the unfixed area is further shortened. Fig.6D In the folded state, the straight-line distance between the boundaries 37 is ultimately approximately equal to the distance between the axes of rotation. As described above, in the folded state, twice the length between the axes and the unfixed boundaries is excessive and the flexible display deflects between the axes of rotation.

[0077] Figure 7 An embodiment of a foldable display according to the present invention is shown. Figure 7 As shown, the flexible display 73 is arranged between the front protective plate 71 and the rear protective plate 72. The flexible display assembly is also fixed to the core plate 76 by the adhesive layer 75, but is not fixed in the unfixed area 74 near the center of the flexible display (that is, the part with the sharpest radius in the folded state). The adhesive layer 75 can be formed by an adhesive sheet, a film, a tape or an optically clear adhesive (OCA). The adhesive layer 75 can have a thickness between 0.05-0.4 mm.

[0078] An exploded view of the bend radius of a foldable display is shown in Fig. 8A and 8B middle. Fig. 8A and 8B have approximately the same unfixed area, however Fig. 8A No auxiliary support structure 88 is provided to govern the shape of the bending region 83 when in the folded state. Figure 8B An embodiment is shown in which the shape of the curved region 83 is governed by the auxiliary support structure 88. Fig. 8A As shown, because there is no auxiliary support structure on the core board in the unfixed area, the flexible display has a slightly steep slope near the boundary 87 between the fixed layer and the unfixed area, which may cause the flexible display 73 to bend backward, essentially stretching beyond the "normal" flat operation, which may cause failure of the flexible display 73. In the case of a flexible capsule-type electrophoretic display, this backward bending may cause a large loss of capsules, which may stop switching or damage the flexible thin film transistors (TFTs) or drive lines. Furthermore, after repeated bending (and stretching) of the curved area 83, the curved area is prone to wrinkling when in a flat state, which reduces the reading experience.

[0079] Thus, the auxiliary support structure 88, which may simply be a thicker portion of the tape, is arranged in the unsecured area, such as Figure 8B Because the step of the unfixed area is filled with the film or tape, the slightly steep slope near the boundary between the fixed layer and the unfixed area becomes moderate, and appropriate deflection can be obtained through the entire bending area 83. In other embodiments, the auxiliary support structure 88 is formed with contoured molding of the core board 76, wherein the adhesive layer 75 is substantially flat at the interface between the flexible display 73 and the core board 76.

[0080] In some embodiments, for example, Fig.9A As shown, the auxiliary support structure 88 is provided by the adhesive layer 75. It is generally preferred when the thickness of the adhesive layer 75 is 0.2 mm or less. If the adhesive layer 75 is greater than 0.2 mm, then Fig. 9B As shown, the auxiliary support structure 88 is generally in the form of a contoured or extended core panel 76 in the unfixed area. Of course, the form of the auxiliary support structure 88 is not determined solely by the width of the adhesive layer 75, but can be selected within an appropriate range as long as a steep slope (backward bending; see Fig. 8A Furthermore, other materials can be used as the auxiliary support structure 88 according to needs.

[0081] Although for example Figure 8B As shown, the preferred embodiment has no back bending, but the size and shape of the final device may require some back bending in the flexible display 73 to achieve the desired device thickness when the device is closed. This may be particularly true when additional layers (e.g., digitization layers (see below)) are added to the device. In cases where a small amount of back bending is required, Fig. 10A and Fig. 10B In comparison, it is better to spread the backward bending over a longer straight line distance of the flexible display 73. Fig. 8A of Fig. 10A As shown, in the case of excessive backward bending, the flexible display 75 may fail due to failure of the capsule or the flexible electronics.

[0082] Fig. 10B A design is shown that can overcome this risk when the design of the device requires a certain amount of backward bending in the flexible display 73. As shown in Figure 10, a gradual backward bending 111 is achieved by increasing the width of the unfixed area 74 so as to reduce the slope of the backward bending at the boundary between the adhesive layer 75 and the unfixed area 74.

[0083] Fig. 10A and Fig. 10B The comparison of the inward bending radius between Fig.11A and Fig. 11B In. Fig.11A In the embodiment, the unfixed length 115 of the unfixed region 74 in the cross-sectional view is shorter, resulting in the inclination angle 113 of the bending region 83 being smaller than the critical angle, thereby increasing the risk of failure as the bending region 83 is repeatedly bent. Fig. 11B In the embodiment of the present invention, the unfixed length 112 increases, resulting in a tilt angle 114 of the bending region 83 being greater than the critical angle. As a result, the flexible display remains functional despite repeated bending.

[0084] Examples

[0085] Fig. 11B The benefits of a gradual backward bend design in the embodiment of the present invention have been demonstrated. A flexible capsule-type electrophoretic display (E Ink Corporation) was prepared, which included a flexible active matrix backplane (Plastic Logic). For this test, the unsecured area 74 was 15 mm wide, while the unsecured length 112 was 6 mm, and the thickness of the adhesive layer was 0.1 mm. After more than 5000 bends from folded to flat state, the flexible display remained fully functional and showed no wrinkles. As a control, a flexible capsule-type electrophoretic display (E Ink Corporation) was prepared with a flexible active matrix backplane (Plastic Logic). For this test, the unsecured area 74 was 15 mm wide, while the unsecured length 112 was 6 mm, and the thickness of the adhesive layer was 0.1 mm. After more than 5000 bends from folded to flat state, the flexible display remained fully functional and showed no wrinkles. Fig.11A A second flexible display device of the same size had an unfastened area 15 mm wide, but had an unfastened length 115 of only 1 mm, and had an adhesive layer thickness of 0.1 mm. After approximately 2,000 bends, the control device began to show signs of failure, including areas where the ink was not switched. At 5,000 bends, the difference in image quality between the two devices was obvious without additional magnification.

[0086] Therefore, the present invention can provide an image display device that is thin and light and can be folded like a book. The image display device can include a flexible display and a bending mechanism designed to be suitable for folding the flexible display. In use, the display device can be carried and stored like a normal book. When the book is opened, it is very flat and can be rotated 90 degrees to allow the book to be read like a single A4 paper.

[0087] Writable flexible display

[0088] The inventive technology of this application can be applied commercially, such as a lightweight and thin e-book or electronic notebook that can be folded in half using a flexible EPD, but by using it at a certain distance different from the above-mentioned smart phone and tablet computer products and by allowing it to connect to those products via Bluetooth, etc., products that use the power saving characteristics inherent in the flexible EPD as a second display can be developed. Preferred embodiments can also include the ability to "write" electronically directly in the book as shown in Figure 7. Fig.12 As shown, a stylus 1205 can be used to interact with a flexible electro-optical display. The stylus can interact with the display using electric fields, electromagnetic fields (e.g., light), capacitance, physical touch, optical sensing, or magnetic fields. The electro-optical display can include a digitizing layer to allow tracking and recording of input, or the stylus can interact directly with the flexible electro-optical display to change the state of the display.

[0089] Many different digitizing systems can be used with the flexible, writable display design shown here. For example, electromagnetic resonance (EMR) digitizing technology from Wacom (Wacom Co., Ltd., Kazuo, Japan) where the stylus tip (including inductive coils) is positioned by an energized digitizing layer located behind the flexible display. Other technologies, such as capacitive touch using an active stylus (N-Trig Technologies) or active electrostatic sensing (Wacom) can be used with the present invention.

[0090] Fig.13 14 is an exploded view of a flexible writable device 1400, which includes a flexible electrophoretic display (EPD) layer 1402, an engagement digitization layer (EMR) 1403, and a core board 1405. Fig.13 As shown, the flexible writable device 1400 has a thickness of about 1 cm and has the feel of a thin book. When in a folded state, the information terminal can be stably carried like a normal book, and when fully opened, it has a substantially flat shape as shown. However, unlike a normal book, the content can be updated electronically, and when combined with a stylus (not shown), the user can take notes and mark documents. The user can also use the flexible writable device 1400 as a notebook or sketchpad.

[0091] Fig.14 14 is a cross-sectional view of the layers of an embodiment of a flexible writable device 1400. Visible content is displayed by a flexible EPD layer 1402, which includes an electrophoretic medium and a flexible active matrix backplane. A digitization layer 1403 is disposed between the flexible EPD layer 1402 and a core board 1404 (or 1405), which provides structural stability and protects the flexible EPD layer 1402 and the digitization layer 1403 from physical impact. The digitization layer 1403 is configured to detect the movement of the stylus and can operate by electromagnetic sensing, capacitive sensing, or optical sensing. The stack additionally includes an adhesive layer to maintain the structure of the layers.

[0092] like Fig.14 As shown, portions of the flexible writable device 1400 can be configured to move relative to each other when the flexible writable device 1400 is folded. Fig.1414, "fixed side"), the flexible EPD layer 1402 is fixed relative to the digitization layer 1403 by a first adhesive layer 1408, and the digitization layer 1403 is fixed to the core board 1404 by a second adhesive layer 1409. In another embodiment, (shown on the right side of FIG. 14, "EPD movable side"), the flexible EPD layer 1402 is configured to move relative to the digitization layer 1403. Typically, the flexible EPD layer 1402 is not allowed to float completely, but is limited by structures 1406 and 1407, which provide the flexible EPD layer 1402 with a track for lateral sliding when the device is folded (see below). However, even when the flexible EPD layer 1402 is not fixed, the digitization layer 1403 is typically fixed to the core board 1404 by an adhesive layer 1410. As described above, both the fixed and unfixed structures retain an unfixed area near the folding axis to provide controlled bending.

[0093] Fig.14 The illustrated flexible writable device 1400 may include additional protective layers, encapsulation layers, or tactile layers to make the flexible writable device 1400 more robust and improve the writing experience using a stylus.

[0094] In the "EPD movable side" embodiment, additional structure is usually provided to maintain good flatness when the device is in the open state. Fig.15A and 15B As shown, the side strip structure 1406 holds the flexible EPD display 1402 from the top, keeps the edge of the flexible EPD display 1402 flat against the digitizing layer 1403, and ultimately keeps the core board 1405 flat when the device is bent. This can be done in Fig. 15B As a result, because the flexible EPD display 1402 can deflect more when the flexible writable device 1400 is closed, a high flatness of the flexible display can be maintained in the open state when there is a digitization layer 1403, which can be much thicker than the flexible EPD display 1402. Optionally, another lubricating layer 1407 can be, for example, a dielectric sheet to help the flexible EPD layer 1402 and the digitization layer 1403 slide against each other.

[0095] Fig.16 is a cross-sectional view showing a hinge portion of a flexible writable device 1600, which includes a first side ( Fig.16 ), wherein the flexible EPD display 1402 is fixed to the digitization layer 1403; and the second side ( Fig.16 ), wherein when the flexible writing device is closed, the flexible EPD display 1402 can move relative to the digitizing layer 140. Fig.16As shown on the right side of the figure, the flexible EPD display 1402 is sandwiched between the side strip structure 1406 and the digitization layer 1403 and the core board 1405. Therefore, the flexible writable device can be opened and closed without squeezing or bending the flexible EPD display 1402. In particular, the synchronous gear 1614 coordinates the rotation of the shaft gear 1613 so that the core boards 1404 and 1405 are smoothly opened and closed. In addition, because the core boards 1404 and 1405 are opened and closed at the same angle, the flexible writable device can be moved between the open and closed states, for example, with one hand.

[0096] In some embodiments, the inclusion of a pressure mechanism 1717 can facilitate closing and bending, and when the flexible writable device 1400 is closed, the pressure mechanism 1717 applies downward pressure to the flexible EPD display 1402 at the bent portion (e.g., the unsecured area). Fig.17 As shown, the pressing mechanism 1717 is arranged against the flexible EPD display 1402 and is connected to the synchronous gear and the shaft gear (1614 and 1613 - see Fig.16 ) together so that the combined layers are Fig.17 1402 and rotates around axes 1719 and 1720 as shown by the curved arrows in FIG. While rotating, the right side of the flexible EPD display 1402 slides along the digitizing layer 1403 to allow the flexible EPD display to be folded without being squeezed.

[0097] Fig.18 Similar to the above Figure 4A and 4B The perspective view of FIG. 1 shows an end view of the complete flexible writable device 1700, which includes a pressure mechanism 1717. The pressure mechanism 1717 can be integrated into the spine cover 21. (The length of the pressure mechanism 1717 has been shortened so that the underlying structure can be seen.) Thus, when the flexible writable device 1700 is closed, the flexible EPD display 1402 is naturally pressed downward from above by the pressure mechanism 1717.

[0098] Touch Sensing Display

[0099] The touch sensor can be integrated into the foldable writable display to produce a foldable writable device with touch sensing 2000. In most cases, the touch sensor does not increase the volume of the device, but makes the foldable writable device with touch sensing 2000 look basically similar to Figure 3A and 3B The foldable device shown.

[0100] An exploded view of a foldable writable device 2000 with touch sensing is shown in Fig.19The device 2000 includes a sensing layer 2003 disposed below the flexible display layer 2002 for detecting the position of a stylus or other marking device. Figure 13-16 As described above, the sensing layer 2003 and the flexible display layer 2002 are supported by the core boards 2004 and 2005. This structure is shown in more detail in Fig. 20 middle, Fig. 20 A cross-section showing the complete structure. Again, as above for Fig.14 As discussed, one end of the flexible display layer 2002 may be unsecured so that it can slide over the sensing layer 2003 when the device moves from an open (flat) state to a closed state. Fig. 20 As shown, the unfixed portion of the flexible display layer (ie, Fig. 20 The right side of the device 2000 is usually not on the side of the unfixed touch sensing unit 2007 (ie, Fig. 20 on the left side of the ).

[0101] like Fig.21 As shown, the touch sensing unit 2007 emits light in a direction substantially parallel to the surface of the flexible display layer 2002. When the operator moves his or her finger in a desired direction on the surface of the flexible display layer 2002, the touch sensing unit 2007 detects that the finger has passed over the emitted light and then identifies the position of the finger. The touch sensing unit 2007 emits light (e.g., infrared light) on the surface of the flexible display layer 2002, detects the light reflected from the object to be detected, such as a finger, and identifies the position of the object to be detected. Fig.21 As shown, the light emitting unit 2019 emits light 2017 through the light guide 2015 in a direction substantially parallel to the surface of the flexible display layer 2002. The reflected light from the object to be measured (e.g., a finger) is received by the light detector 2016, where the reflected light is collected by the light guide 2015. The light emitting unit 2019 can be a standard IR light emitting diode, which can be purchased from Luminus (Sunnyvale, California), for example. The detector can be an IR photodiode (or array thereof) available from Everlight Electronics (Carrollton, Texas). In some embodiments, the light emitting unit 2019, the light detector 2016 and the light guide 2015 are integrated into a single system, which can be purchased from Leyard (Hillsboro, Oregon), for example.

[0102] In most cases, the light 2017 is emitted substantially parallel to the surface of the flexible display layer 2002, that is, the preferred structure when the device 2000 is in a completely flat state. However, the device 2000 does not need to be completely flat in order for the touch sensing unit 2007 to operate effectively. Fig.22AAs shown, when the core plates 2004 and 2005 are not completely flat, for example, if they form a slightly curved angle, for example, 174° or more, the touch sensing unit can easily work. Furthermore, because the light 2017 is emitted at a small height (h) above the flexible display layer 2002, and because the lens of the light emitting unit 2019 causes the emission at an angle (θ) (not parallel), as shown in FIG. Fig. 22B As shown, for many slightly curved angles, a simple light emitting unit 2019 can cover the entire area of ​​the surface of the flexible display layer 2002. In some embodiments, when the core boards 2004 and 2005 define an angle less than 180° (e.g., between 180° and 145°, e.g., between 180° and 150°, e.g., between 180° and 165°), the device 2000 has functional touch sensing.

[0103] An emission angle can be calculated below which the device will cease to allow IR sensing across the entire plane of the flexible display layer 2002. Fig. 22B . When the opening angle is 174°, Hh is approximately 2×ζ×θ×(π / 180), and H is approximately ζ×6×(π / 180). Thus, θ is approximately 3-90×h / (ζ×π). In order to cover the entire area of ​​the flexible display, the angle between the direction of the light emitted by the touch sensing unit 7 and the direction parallel to the surface of the flexible display 2 is preferably greater than θ. For example, if h is 5 mm and ζ is 100 mm, θ is approximately 1.56. Thus, the angle between the direction of the light and the direction parallel to the surface is preferably greater than 1.56°. More preferably, the angle is greater than 2°.

[0104] This does not mean that the touch function must be limited to the core boards 2004 and 2005 being substantially coplanar. Fig.23 As shown, the directionality of the light emitting unit 2019 can change with the bending angle of the device 2000. This can be accomplished, for example, by an angle linkage mechanism 2026 that includes synchronous gears that rotate the touch sensing unit when the device 2000 is opened and closed.

[0105] Fig.24Another embodiment shown includes two different touch sensing units 2007A and 2007B, each with a different type of light source. This embodiment also includes filters 2501 and 2502 to ensure that only light from the desired touch sensing unit is received at that particular touch sensor. Thus, when the device is in a partially open state, the touch sensing unit 2007A or 2007B will only detect touches on that side. When the device is fully open, the two sensors will operate in the same space, however, any dual sensing can be accommodated by comparing the detection positions of the two touch sensing units or simply taking the average of the two measurement positions.

[0106] Because the portable information device of the present application includes a touch sensing unit only on one side of the main body, a lightweight and thin terminal and a spread type touch panel can be realized. Therefore, the following problems can be solved: the touch panel is bent and damaged, and when the portable information device is used with a specific angle between the panels, the touch panel detects an erroneous touch at the bent portion under pressure. The inventive technology of the present application produces a foldable and writable touch sensing device that can be integrated into the device ecosystem (including WIFI, Bluetooth, etc.).

[0107] definition

[0108] The term "electro-optical" as applied to a material or display is used herein in its conventional sense in the imaging arts to refer to a material having first and second display states that differ in at least one optical property, wherein the material is changed from its first display state to its second display state by application of an electric field to the material. While the optical property is typically color perceptible to the human eye, it may be other optical properties, such as light transmission, reflectivity, and luminous brightness, or, for displays intended for machine reading, false color in the sense of reflectivity variations at electromagnetic wavelengths outside the visible range.

[0109] The terms "gray state" or "grayscale" are used herein in their conventional meaning in imaging technology to refer to the state between the two extreme optical states of a pixel, and do not necessarily imply a black-white transition between the two extreme states. For example, several of the E Ink patents and published applications mentioned below describe electrophoretic displays in which the extreme states are white and dark blue, such that the intermediate "gray state" may actually be light blue. More specifically, as previously described, the change in optical state may not be a color change at all. The terms "black" and "white" may be used below to refer to the two extreme optical states of the display, and should be understood to generally include extreme optical states that are not strictly black and white, such as the white and dark blue states mentioned above. The term "monochrome" may be used herein to refer to a drive scheme that drives a pixel only to its two extreme optical states without an intermediate gray state.

[0110] Some electro-optical materials are solid in the sense that the material has a solid outer surface, although the material may, and often does, have internal liquid- or gas-filled spaces. Such displays using solid electro-optical materials may conveniently be referred to hereinafter as "solid-state electro-optical displays." Thus, the term "solid-state electro-optical display" includes rotating two-color component displays, capsule-type electrophoretic displays, microcell electrophoretic displays, and capsule-type liquid crystal displays.

[0111] The terms "bistable" and "bistable" are used herein in their conventional sense in the art to refer to a display including display elements having first and second display states that differ in at least one optical property, and after any given element is driven to assume its first or second display state by an addressing pulse of finite duration, and after the addressing pulse has terminated, that state persists for at least several times, e.g., at least four times, the shortest duration required for the addressing pulse to change the state of the display element. U.S. Patent No. 7,170,670 shows that some particle-based electrophoretic displays with grayscale are stable not only in the extreme black and white states, but also in intermediate gray states, as are some other types of electro-optical displays. Such displays may properly be referred to as "multistable" rather than bistable, but for convenience, the term "bistable" may be used herein to cover both bistable and multistable displays.

[0112] It will be apparent to those skilled in the art that many changes and modifications may be made to the specific embodiments of the invention described above without departing from the scope of the invention. Therefore, the entire foregoing description is to be interpreted as illustrative rather than restrictive.

Claims

1. A flexible image display device capable of displaying an image on a bendable portion, receiving input using a stylus pen, and receiving input from a user's touch, the flexible image display device comprising: A flexible electro-optical display comprising two planar portions and a bendable portion, the bendable portion being flexible and capable of displaying an image; two planar support members, each planar support member being rectangular and comprising a fixed region and an unfixed region, wherein the fixed region is coupled to and supports one of the planar portions of the flexible electro-optic display, and wherein the unfixed region is not coupled to the flexible electro-optic display; a bending mechanism comprising two separate rotation axes parallel to a centerline defined by the flexible electro-optical display, wherein each of the two rotation axes is disposed apart from the centerline defined by the flexible electro-optical display, and wherein each of the rotation axes defines a pivot axis of a planar support member, and wherein a distance between the two rotation axes is disposed at least twice a minimum radius of curvature of the flexible image display device; a digitizing layer for detecting the position of a stylus, disposed between the flexible electro-optical display and the planar support member; and A touch sensor unit is configured to emit light in a direction substantially parallel to a surface of the planar portion of the flexible electro-optical display and detect light reflected from a touch object.

2. The flexible image display device according to claim 1, wherein: A portion of the flexible electro-optical display is bonded to the planar support member in the securing region.

3. The flexible image display device according to claim 1, wherein: A portion of the flexible electro-optical display is configured to slide freely against a support member.

4. The flexible image display device according to claim 1, wherein: The flexible electro-optical display includes an electrophoretic medium.

5. The flexible image display device according to claim 4, wherein: The electrophoretic medium is encapsulated.

6. The flexible image display device according to claim 4, wherein: The electrophoretic medium is distributed in a plurality of microcells.

7. The flexible image display device according to claim 1, wherein: Each of the two separate rotating shafts includes a rotating gear coupled to one end of each rotating shaft, and the bending mechanism further includes a rotating synchronizer for synchronously rotating the rotating gears.

8. The flexible image display device according to claim 7, wherein: The rotation synchronizer includes two separate synchronization gears, wherein each of the synchronization gears meshes with the other synchronization gear and one of the rotation gears coupled to a rotation shaft.

9. The flexible image display device according to claim 1, wherein: The bending mechanism also includes a void volume that exceeds the volume swept by the unsecured regions of the two planar support members as they rotate about their respective axes of rotation. 10 . The flexible image display device according to claim 1 , further comprising an auxiliary supporting structure configured to prevent backward bending of the bendable region.

11. The flexible image display device according to claim 1, wherein: The flexible electro-optical display includes a flexible backplane including an array of pixels.

12. The flexible image display device according to claim 11, wherein: The flexible backplane includes at least 100 pixels per 2.5 cm linear distance across the backplane.

13. The flexible image display device according to claim 1, wherein: The digitization layer is an electromagnetic resonance (EMR) digitization layer.

14. The flexible image display device according to claim 1, wherein: The digitization layer is joined to allow it to be folded with the flexible electro-optical display.

15. The flexible image display device according to claim 1, further comprising a second touch sensor unit configured to emit light in a direction substantially parallel to a surface of the planar portion of the flexible electro-optical display and detect light reflected from a touch object.

16. The flexible image display device according to claim 15, wherein: The touch sensor and the second touch sensor emit light of different frequencies.

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