CN112292636A

CN112292636A - Device for low power reflective image display

Info

Publication number: CN112292636A
Application number: CN201980033150.3A
Authority: CN
Inventors: 弗兰克·W·J·克里斯蒂安
Original assignee: Concord Hong Kong International Education Co ltd
Current assignee: Wuxi Keling Display Technology Co ltd
Priority date: 2018-05-30
Filing date: 2019-05-30
Publication date: 2021-01-29
Also published as: WO2019232207A1

Abstract

Electrophoretic displays capable of operating at low voltages to move electrophoretically mobile particles may be driven by low power devices. The device may include Memory-In-Chip (MIP) technology to enhance or create image stability. The MIP may include 1-bit memory SRAM or DRAM circuitry located in one or more pixels in a TFT array back plane.

Description

Device for low power reflective image display

Cross Reference to Related Applications

The present disclosure claims priority of U.S. provisional application serial No. 62/678,196 (entitled "device for low power reflective image display") filed on 30/5/2018, the specification of which is incorporated herein in its entirety.

Technical Field

The present disclosure relates to a device for a reflective image display. The disclosed embodiments relate generally to the use of in-pixel memory technology in electrophoretic based displays. In one embodiment, the present disclosure relates to an apparatus for a low power consumption electrophoresis-based image display, including a 1-bit SRAM circuit or a 1-bit DRAM circuit.

Background

Conventional reflective electrophoretic displays (EPDs) comprise one or more electrophoretically mobile particles suspended in an air or liquid medium between two or more electrodes. The electrophoretically mobile particles can be moved by applying a bias voltage between opposing electrodes and across a medium to produce an image or text, thereby conveying information to a viewer. Conventional EPD-based reflective image displays can have image stability. Image stability in EPD is the ability to retain an image when the display is powered off. The level of image stability can be designed to vary from a few minutes to several days to several weeks. Increased image stability in EPDs generally results in reduced power consumption and increased battery life.

Drawings

These and other embodiments of the present disclosure will be discussed with reference to the following exemplary and non-limiting illustrations, in which like elements are similarly numbered, and in which:

FIG. 1 schematically illustrates one embodiment of a device for a low power EPD based reflective image display;

FIG. 2 illustrates an embodiment of a microencapsulated reflective image display including memory circuitry;

FIG. 3A schematically illustrates an embodiment of a reflective image display based on total internal reflection including a memory circuit;

FIG. 3B schematically illustrates a cross-section of a portion of a TIR-based display including memory circuitry showing the approximate location of the evanescent wave region;

FIG. 3C schematically illustrates a cross-section of a portion of a top view of a TIR based reflective image display including memory circuitry;

FIG. 4 schematically illustrates an embodiment of a microcup-based reflective image display including memory circuitry; and

fig. 5 schematically illustrates an exemplary system for implementing embodiments of the present disclosure.

Detailed Description

Throughout the following description, specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive or exclusive sense.

The present disclosure relates generally to EPD based reflective image displays. According to certain embodiments of the present disclosure, the EPD-based reflectance image may remain substantially stable by using Memory-in-Pixel (MIP) techniques. Image stability means that the image continues to be displayed even when power is removed from the display module (which is the case only if the electrophoretic ink material itself has inherent stability), or when the displayed image does not require constant updating of surrounding electronic drivers. MIP techniques can store a 1-bit value locally at a pixel (on/off state). This may save power because the switching material (e.g., electrophoretic ink) may be refreshed locally, rather than always scanning the display with image data during each frame of video. The display may consume almost zero power in this state.

In an exemplary embodiment, the means for driving the dynamic and video images for the EPD based reflective image display may include MIP technology. The device may include a back panel including an array of pixels. Each pixel may include a Thin Film Transistor (TFT), and further include a storage element of the display for driving still images, video data, driving voltages, and waveforms. MIP techniques may include one or more of Static Random Access Memory (SRAM) circuitry (circuit) or Dynamic Random Access Memory (DRAM) circuitry. The back electrode in the EPD based reflective image display may include 1-bit SRAM circuits or 1-bit DRAM circuits. The waveform may include one or more of various drive voltages of different amplitudes, charge polarities, or durations for which voltages may be applied.

FIG. 1 schematically illustrates one embodiment of a device for a low power EPD based reflective image display. The device can be used to drive EPD based reflective image displays. The apparatus 100 may include a back panel. The back panel 102 may also include an array of pixels 104 arranged in columns or rows. For example, pixel P1, L1 is pixel 1 in row 1. For illustrative purposes, the back plane 102 in FIG. 1 includes 96 columns of pixels and 96 rows of pixels (only a few of which are shown in embodiment 100 for clarity). Other back panels of fewer or more pixels and rows may be used. The pixels 104 may be arranged on a support plate comprising glass, metal or polymer. Each pixel may include at least one TFT. In an exemplary embodiment, one or more pixels may include a memory circuit 106. This is shown in the enlarged view 108 of a single pixel (P96, L1). The memory circuit 106 is capable of storing one or more bits of pixel data.

For illustrative purposes, the back plane 102 also includes a Random Access Memory (RAM) 106. The RAM 106 may exist in at least one pixel as shown in fig. 1. The RAM 106 may include Static Random Access Memory (SRAM) circuitry. In one embodiment, the SRAM circuit may include four transistors, with each bit storing an additional two transistors to control access to the memory cells forming a six transistor SRAM. In other embodiments, the SRAM chips may include 8, 10, 12, or more transistors per chip. The RAM 106 may include at least 1-bit Static Random Access Memory (SRAM) circuitry. Each bit can have two values 0 or 1.

The RAM 106 may include Dynamic Random Access Memory (DRAM) circuits. In one embodiment, a DRAM circuit may include at least one capacitor and at least one transistor per bit of data. The memory circuitry 106 may include at least 1-bit Dynamic Random Access Memory (DRAM) circuitry. Each bit can have two values 0 or 1.

SRAM or DRAM memory circuits are capable of storing information once written. This may allow the design of products with ultra-low power consumption and long battery life. The embedded pixel memory circuit may store graphics data, so continuous refreshing of the SRAM memory circuit may not be required for static images. In some embodiments, the DRAM may need to be refreshed each time the pixel is driven. In other embodiments, the DRAM circuit may further include an output buffer to isolate the memory circuit from the pixel electrode. The additional output buffer may further include a TFT and a capacitor. Furthermore, in changing images, such as video, each pixel in the display holds image information, so the image only has to be overwritten in pixels whose content has changed. This is commonly referred to as MIP techniques.

MIP techniques generally require lower operating voltages. Conventional reflective electronic paper technology commercialized by electronic Ink (E Ink) corporation cannot utilize MIP technology due to the need for higher operating voltages (-15V) to operate the display. Other reflective display technologies are needed to operate the display using even higher voltages up to about 80V. Therefore, these conventional reflective display technologies cannot utilize MIP technology. In some embodiments, MIP technology may be used in combination with reflective image display technology that can be driven in the range of 0.1V to 10V. In other embodiments, MIP technology may be used in combination with reflective image display technology that can be driven in the range of 1V to 10V. In further embodiments, MIP technology may be used in combination with reflective image display technology that can be driven in the range of 5V to 10V. In further embodiments, MIP technology may be used in combination with reflective image display technology that can be driven in the range of 0.1V to 5V. This is an important advantage of low voltage EPD-based displays over other higher operating voltage reflective display technologies, as it can allow low power EPD reflective displays to be used in, for example, Electronic Shelf Label (ESL), (electronic reader) eReaders, and IoT-based devices.

The addition of MIP technology improves image stability in EPD-based image displays. As described above, when an image is maintained even after the power is turned off or set to 0V, image stability occurs. Image stability may be created by using chemical or physical phenomena such as van der waals forces, ionic or other intermolecular forces. MIP techniques can be used in conjunction with the intermolecular forces to produce or improve low power performance in EPD-based reflective image displays.

Device 100 may also include one or more memory gate lines 110, one or more signal lines 112, or one or more ink drivers 114. The ink driver 114 may provide isolation between the memory circuitry and the pixel electrodes. Memory gate lines 110 and signal lines 112 electrically connect the pixels in array 104. The device 100 may also include a common electrode (VCOM)116 that provides a polarity inversion signal that drives a common front electrode and a pixel cell 118 driven by a rear TFT electrode in a pixel. In an exemplary embodiment, pixel cell 118 includes anything between the front and back electrodes in an electrophoretic display. Pixel element 118 includes an electrophoretic ink (also referred to as a suspension) that modulates reflected light. The ink may comprise an air or liquid medium and a plurality of electrophoretically mobile particles. In some embodiments, pixel cell 118 may include an electrowetting system. The electrowetting system may further comprise an electrophoretically mobile polar fluid and a non-polar fluid, wherein one of the fluids comprises a color (wherein the color may be formed by a dye or a pigment). The pixel cell 118 may also include one or more dielectric layers or microcup walls.

In an exemplary embodiment, the e-paper technology utilizing one or more electrophoretically mobile particles in microcapsules in a liquid or air medium may be driven by MIP-based technology at operating voltages in the range of about 0.1V to 10V. The one or more electrophoretically mobile particles can include a first plurality of particles having a positive charge polarity of a first color and a second plurality of particles having a negative charge polarity of a second color different from the color of the first plurality of particles. In other embodiments, the plurality of particles in an EPD including MIP techniques may include different charge values, electrophoretic mobilities, and colors.

Figure 2 illustrates an embodiment of a microencapsulated reflective image display including memory circuitry. The microencapsulated reflective image display embodiment 200 includes a transparent front plate 202 with an outer surface 204 of the transparent front plate 202 facing a viewer 206. The front plate 202 may be composed of glass or polymer. The display 200 may also include a back support plate 208. The plate 208 may comprise one or more of a polymer, glass, or metal. The front plate 202 and the back plate 208 may form a gap 210 therebetween.

Fig. 2 may represent an exemplary embodiment of a pixel. That is, a pixel can be considered to include front plate 202 to back plate 208 and everything in between (e.g., front electrode 222, binder 220, microcapsules 212,

particles

214, 216, medium 218, back electrode 224, and optional back electrode 208).

A plurality of layers of microcapsules 212 are positioned within the gap 210. The microcapsules 212 may include a polymer-based shell. In one embodiment, the microcapsules 212 may include a first plurality of charged electrophoretically-mobile particles 214 of a first color (represented in FIG. 2 as black particles) and a second plurality of oppositely-charged electrophoretically-mobile particles 216 of a second color (represented in FIG. 2 as white particles), in a liquid or air medium 218. In some embodiments, there may be another plurality of differently colored particles comprising different electrophoretic mobilities. In some embodiments, the

particles

214, 216 may include inorganic materials, such as metal oxides or organic materials. In other embodiments, the

particles

214, 216 may comprise a combination of organic and inorganic materials. In an exemplary embodiment, one of the plurality of

particles

214, 216 may include TiO₂. In an exemplary embodiment, one of the plurality of

particles

214, 216 may include copper chromate (cucrri), carbon black, or Fe₃O₄。

In an exemplary embodiment, the medium 218 may be a substantially transparent liquid. The medium 218 may also include one or more of a charge control agent, a surfactant, or a viscosity modifier. The medium 218 may comprise a hydrocarbon-based liquid. In some embodiments, the medium 218 may include a dye. In an exemplary embodiment, medium 218 may include a dye and a plurality of electrophoretically mobile particles having one charge polarity and color. In exemplary embodiments, polyisobutylene may be used as the viscosity modifier. In an exemplary embodiment, the microcapsules 212 may be bonded together using a binder 220.

The display 200 in fig. 2 comprises a transparent front electrode layer 222. In an exemplary embodiment, the front electrode 222 is located on an inner surface of the front plate 202. The front electrode may comprise indium oxideTin (ITO), metal nanowires in a polymer matrix or wires such as Beuton (BAYTRON)^TM) One or more of the conductive polymers of (a).

The display 200 also includes a back electrode layer 224. The back electrode 224 may comprise an active matrix array of Thin Film Transistors (TFTs), a passive matrix array of electrodes, or a direct drive array of pixelated electrodes. The display 200 may also include a bias source 226. The bias source 226 may provide a bias across the gap 210 between the front electrode 222 and the back electrode 224. The bias across the gap 226 may move the charged electrophoretically

mobile particles

214, 216 to either the front or back electrode. Movement of the

particles

214, 216 in various combinations toward the front electrode 222 in the display 200 may be used to form images or text viewed by the viewer 206. In an exemplary embodiment, the display 200 may be driven in a range of about 0.1V to 10V.

In an exemplary embodiment, back electrode 224 includes back plane electronic device embodiment 100 depicted in FIG. 1 in display 200. Layer 224 may include SRAM or DRAM circuitry as previously described herein. In an exemplary embodiment, layer 224 may include 1-bit SRAM circuitry or 1-bit DRAM circuitry as previously described herein.

In some embodiments, the display 200 may also include a directional front light system 228. The front light system may further comprise a light source 230 and a waveguide 232. The light source 230 emits light into the waveguide 232. The waveguide 232 may also include a light extraction unit (not shown) to extract light from the waveguide and direct the light to the microcapsule layer 212.

In some embodiments, the display 200 may include an Ambient Light Sensor (ALS) or a front light controller 236. In dim lighting conditions, the ALS 234 may detect weak light and send a signal to the front light controller 236 to increase the power to the light source 230, thereby increasing the light emitted from the waveguide 232. In bright lighting conditions, the ALS 234 may detect high levels of light and send a signal to the front light controller 236 to reduce power to the light source 230, thereby reducing the light emitted from the waveguide 232.

In some embodiments, display 200 may be included in front electrode 222 or back electrode 224At least one dielectric layer on one or both. In some embodiments, the dielectric layer may be a polymer such as parylene, halogenated parylene, or polyimide. In other embodiments, the dielectric layer may be, for example, SiN_xOr for example AI2O3 or SiO₂Metal oxide of one or both of them.

Figure 3A illustrates an embodiment of a reflective image display based on total internal reflection including a memory circuit. A Total Internal Reflection (TIR) -based reflective display 300 includes a transparent front plate 302 with an outer surface 304 of the transparent front plate 302 facing an observer 306. The display 300 further comprises a plurality 308 of layers of individual convex protrusions 310, a back support plate 312, a transparent front electrode 314 and a back electrode 316 on the surface of the plurality 308 of convex protrusions. In some embodiments, the protrusion 310 may be hemispherical or semi-hemispherical. The protrusions may be arranged in a close-packed array. In an exemplary embodiment, the protrusion 310 may have a refractive index in the range of about 1.5 to 2.2.

The back electrode 316 may include a passive matrix electrode array, a Thin Film Transistor (TFT) array, or a direct drive electrode array. The array of back electrodes may be formed in an array of pixels. Fig. 3A also shows a low index medium 318 disposed within a cavity or gap 320, the cavity or gap 320 formed between the surface of the protrusion 308 and the back support plate 312. The medium 318 may be air or liquid. In some embodiments, the medium 318 may comprise a fluorinated liquid. In an exemplary embodiment, medium 318 may have a refractive index in the range of about 1 to 1.5. In an exemplary embodiment, the refractive index of protrusion 310 is greater than the refractive index of medium 318. Medium 318 contains a plurality of light-absorbing electrophoretically mobile particles 322, as previously described herein. In some embodiments, medium 318 contains a first plurality of electrophoretically-mobile particles of a first charge and a first color and a second plurality of electrophoretically-mobile particles of an opposite charge and a second color. In other embodiments, the second plurality of particles may be contained in a medium that is not electrophoretically mobile.

The display 300 may also include a voltage source 324, the voltage source 324 capable of generating a bias voltage across the cavity 320. The display 300 may also include one or more

dielectric layers

326, 328 and a color filter layer 330, the one or more

dielectric layers

326, 328 being located on the front electrode 314 or the back electrode 316 or on both the front and back electrodes. In some embodiments, the

dielectric layers

326, 328 may be polymers such as parylene, halogenated parylene, or polyimide. In other embodiments, the dielectric layer may be a nitride such as SiNx or a metal oxide such as one or both of AI2O3 or SiCh. In fig. 3A, a color filter layer 330 is located between the plate 302 and the convex protrusion layer 308. A color filter layer 330 may also be located on the outer surface 304 of the panel 302, the outer surface 304 facing the viewer 306. The addition of a Color Filter Array (CFA) layer on the front surface of the display is a conventional method of converting a black and white reflective display into a full color display.

The color filter layer typically includes one or more sub-pixel color filters. The sub-pixel color filters may include one or more colors of red, green, blue, white, black, transparent, cyan, magenta, or yellow. The sub-pixel color filters are typically grouped into two or more colors and arranged in a repeatable pattern. The repeatable pattern constitutes a pixel, such as an RGB (red-green-blue) sub-pixel or an RGBW (red-green-blue-white) sub-pixel. For illustrative purposes, a portion of TIR based display 300 in FIG. 3A includes color filter layer 330, and also includes red sub-pixel color filters 332, green sub-pixel color filters 334, and blue sub-pixel color filters 336. Other sub-pixel color filter combinations may be used. In an exemplary embodiment, the sub-pixel color filters may be aligned with a pixel cell, which may also be aligned with a single TFT, wherein the pixel cell further includes a memory circuit.

Protrusion 310 and medium 318 may have different refractive indices, which are defined by critical angle 9_CAnd (5) characterizing. The critical angle characterizes the interface (having a refractive index η 3) between the surface of the protrusion 310 (having a refractive index η i) and the low refractive index medium 318. Light rays incident on the interface at angles less than thetac may be transmitted through the interface. Light rays incident on the interface at angles greater than thetac may undergo TIR at the interface. Small critical angle (e.g. ofLess than about 50 deg.) is preferred at the TIR interface because this provides a wide range of angles at which TIR may occur. It is desirable to have fluid medium 318 have as low an index of refraction as possible (1/3) and to have the protrusions be constructed of a material having as high an index of refraction as possible (1/1). The critical angle θ c is calculated by the following equation (equation 1):

as the particles 322 electrophoretically move near the interface of the high index protrusion 310 and low index medium 318 toward the front electrode 314, they enter a location known as the "evanescent wave region". In this position, particles 322 may frustrate TIR. The depth of the evanescent wave region may typically be about 0.25Dm, although this may vary with the wavelength of the incident light and the refractive indices of the front plate and the medium. This is shown to the right of dashed line 338 and by the absorption of incident rays 340 and 342 by particle 322. This area of the display, for example at a pixel, may appear dark, colored or gray to the viewer 306.

As the particles exit front plate 302 and exit the evanescent wave region toward back electrode 316 (as shown to the left of dashed line 338), incident light rays may be totally internally reflected at the surface of dielectric layer 326 at the interface between convex protrusion array 308 and medium 318. This is represented by an incident ray 344, which incident ray 344 is totally internally reflected and leaves the display as a reflected ray 346 towards the viewer 306. The display pixels may appear white, bright, colored, or gray to a viewer.

TIR-based display 300 may also include a sidewall 348 that bridges front panel 302 to back panel 312. The sidewalls may include at least one dielectric layer 350. In some embodiments, the dielectric layer 350 may be a polymer such as parylene, halogenated parylene, or polyimide. In other embodiments, the dielectric layer may be, for example, SiN_xOr for example AI2O3 or SiO₂Metal oxide of one or both of them. The display 300 may also include a directional front light system 352. The front light system 352 may include a light source 354 and a waveAnd a guide 356. In some embodiments, the frontlight system 352 may also include an ALS 360 and a frontlight controller 362.

FIG. 3B schematically shows a cross-section of a portion of a TIR-based display including memory circuitry showing the approximate location of the evanescent wave region. Fig. 380 in fig. 3B is a close-up view of a portion of fig. 300 in fig. 3A. Evanescent wave region 382 is located at the interface of dielectric layer 326 and medium 318. This position is shown in diagram 380, where evanescent wave region 382 is located approximately between dashed line 384 and dielectric layer 326. It should be noted that evanescent wave region 382 is illustrative and its depth or extent may vary depending on the design of the display and the materials of construction used. The evanescent wave is generally conformal to the surface of the raised layer 308. The depth of the evanescent wave region is about one micron, as previously described.

Figure 3C schematically illustrates a cross-section of a portion of a top view of a TIR based reflective image display including memory circuitry. The view in fig. 3C is looking down on the surface 304 of the board 302. This is a view of viewer 306 in fig. 3A-3B. The convex protrusions 310 are arranged in layers 308 on opposite sides of the plate 302 and are depicted as dashed circles representing hemispheres arranged in a close-packed array. Other arrangements of the male projections 310 are also possible. The protrusions 310 may be arranged in rows that are not closely packed.

In an exemplary embodiment, a TIR-based display 300 including electrophoretically mobile particles in a liquid or air medium may be driven by MIP-based techniques at an operating voltage in the range of about 0.1V to 10V. An image may be formed in TIR-based display 300 by moving electrophoretically mobile particles into and out of the evanescent wave region at the pixel to frustrate TIR. In an exemplary embodiment, the back electrode 316 includes the back plane electronic device embodiment 100 depicted in FIG. 1 in the display 300. In an exemplary embodiment, the rear electrode 316 in the display 300 may include at least one TFT. In an exemplary embodiment, the back electrode 316 in the display 300 may include at least one SRAM or DRAM memory circuit. In an exemplary embodiment, the display 300 may include a 1-bit SRAM circuit or a 1-bit DRAM circuit.

Figure 4 schematically illustrates an embodiment of a microcup-based reflective image display including a memory circuit. The microcup-based reflective display 400 includes a transparent front plate 402 with an outer surface 404 of the transparent front plate 402 facing a viewer 406. The display 400 includes a back support plate 408 that further forms a gap 410. Included within the gap 410 is a wall 412 that fully or partially bridges the rear plate 408 to the front plate 402. The walls 412 may form microcups 414. The microcups 414 may also be referred to as microwells. The microcups 414 may be in the form of a square, rectangle, hexagon, circle, or any other shape. The microcups 414 include an air or liquid medium 416. One or more charged electrophoretically mobile particles may be suspended within medium 416. In some embodiments, medium 416 may include a first color having a plurality of electrophoretically-mobile particles of a second color. In an exemplary embodiment, the medium 416 may include a first plurality of positively charged particles (represented as white particles in fig. 4) of a first color 418, and a second plurality of particles 420 (represented as black particles in fig. 4) of an oppositely charged and second color.

The display 400 in fig. 4 also includes a transparent front electrode 422 on the inner side of the plate 402, and a back electrode layer 424 on the inner surface of the back plate 408. In an exemplary embodiment, the electrode layer 424 may be pixelated. Each pixel may include at least one TFT. The display 400 includes a bias source 426. A bias source 426 may be used to create a bias across the gap 410 to electrophoretically move the

particles

418, 420 to the front electrode 422 or the back electrode 424.

In some embodiments, the front electrode layer 422 or the back electrode layer 424 may include at least one dielectric layer (not shown). In some embodiments, the dielectric layer may be a polymer such as parylene, halogenated parylene, or polyimide. In other embodiments, the dielectric layer may be, for example, SiN_xOr nitride such as AhO₃Or SiO₂Metal oxide of one or both of them.

The display 400 may also include a front light system 428. The front light system 428 may also include a light source 430 and a light guide 432. In an exemplary embodiment, the light guide 432 may include a light extraction unit (not shown). The front light system 428 may also include an ALS 434 or a front light controller 436.

The display 400 may operate as follows. When the dark particles 420 are near the front electrode surface, the incident light may be absorbed. This is represented by

rays

438, 440. This portion of the display 400 that absorbs light may appear dark to an observer 406. When the light or white particles 418 are brought to the front electrode surface 422 by applying a bias of the correct polarity, light may be reflected off the particles that appear bright or white to the viewer 406. This is represented by incident ray 442, which is reflected off of particle 418 as reflected ray 444. By bringing different combinations of the various colored particles to the front of the microcups 414 (the front of the microcups 414 being proximate the front electrode 422 facing the viewer 406), an image or text can be formed to convey information to the viewer 406. In some embodiments, display 400 may also include a color filter layer similar to layer 330 in display 300 to form color images. In an exemplary embodiment, at least one color filter subpixel may be substantially aligned with the microcups 414.

In an exemplary embodiment, the microcup-based display 400 including electrophoretically mobile particles in a liquid or air medium may be driven by MIP-based techniques at an operating voltage in the range of about 0.1V to 10V. An image may be formed in the microcup-based display 400 by moving the electrophoretically mobile particles to either the front electrode 422 or the back electrode 424. In an exemplary embodiment, back electrode 424 includes back plane electronic device embodiment 100 depicted in FIG. 1 in display 400. In an exemplary embodiment, the rear electrode 424 in the display 400 may include at least one TFT. In an exemplary embodiment, the back electrode 424 in the display 400 may include at least one SRAM or DRAM memory circuit. In an exemplary embodiment, the display 400 may include a 1-bit SRAM circuit or a 1-bit DRAM circuit.

Pulsed and DC (direct current) drive schemes may be utilized to derive the desired optical state (i.e., gray state) levels within the pixels that maintain the EPD-based display embodiments described herein. The drive scheme may include one or more of a variable applied positive or negative voltage, a variable voltage ON time (i.e., ON state pulse width), and a variable voltage OFF time (i.e., OFF state pulse width).

Fig. 5 schematically illustrates an exemplary system for implementing embodiments of the present disclosure. In fig. 5, the

displays

200, 300, 400 are controlled by a controller 540, the controller 540 having a processor 530 and a memory 520. Other control mechanisms and/or devices may be included in controller 540 without departing from the disclosed principles. The controller 540 may define hardware, software, or a combination of hardware and software. For example, the controller 540 may define a processor programmed with instructions (e.g., firmware). Processor 530 may be a real processor or a virtual processor. Similarly, memory 520 may be real memory (i.e., hardware) or virtual memory (i.e., software).

The memory 520 may store instructions for driving the

display

200, 300, 400 that are executed by the processor 530. The instructions may be configured to operate the

display

200, 300, 400. In one embodiment, the instructions may include biasing electrodes associated with the

display

200, 300, 400 via a power supply 550. When biased, the electrodes may cause the electrophoretic particles to move towards or away from a region proximate the surface, thereby absorbing or reflecting light received at the front transparent plate. The electrophoretically mobile particles (e.g.,

particles

214, 216 in fig. 2; particle 322 in fig. 3A;

particles

418, 420 in fig. 4) can be controlled by appropriately biasing the electrodes.

In an exemplary embodiment, at least one pixel in a back panel including a TFT array with MIP technology may be substantially aligned with a color subpixel in a color filter array in an EPD. In an exemplary embodiment, at least one SRAM or DRAM circuit may be aligned with one pixel in any of the

displays

200, 300, or 400. In an exemplary embodiment, at least one 1-bit SRAM or 1-bit DRAM circuit may be aligned with one pixel in any of the

displays

200, 300, or 400. Each pixel aligned with an SRAM or DRAM circuit may also be aligned with a color sub-pixel filter, such as red, green, blue, or white.

In the exemplary display embodiments described herein, it may be used in an Internet of Things (IoT) device. The IoT devices may include local wireless or wired communication interfaces to establish local wireless or wired communication links with one or more IoT hubs or client devices. The IoT devices may also include a secure communication channel that communicates with the IoT service over the internet using a local wireless or wired communication link. IoT devices that include one or more of the display devices described herein may also include sensors. The sensors may include one or more of temperature, humidity, light, sound, motion, vibration, proximity, gas, or thermal sensors. An IoT device including one or more of the display devices described herein may interface with an appliance such as a refrigerator, freezer, Television (TV), Closed Caption TV (CCTV), stereo, heater, ventilator, air conditioning (HVAC) system, dust collection robot, air purifier, lighting system, washing machine, dryer, oven, fire alarm, home security system, sink device, dehumidifier, or dishwasher. An IoT device including one or more display devices described herein may interface with a health monitoring system such as cardiac monitoring, diabetes monitoring, temperature monitoring, a biochip transponder, or a pedometer. An IoT device including one or more display devices described herein may interface with a transportation monitoring system such as an automobile, motorcycle, bicycle, scooter, watercraft, bus, or aircraft.

In the exemplary display embodiments described herein, they may be used in IoT and non-IoT applications, such as, but not limited to, e-book readers, portable computers, tablet computers, cellular phones, smart cards, signs, watches, wearables, military display applications, automotive displays, automotive license plates, shelf labels, flash drives, and outdoor billboards or outdoor signs that include displays. The display may be powered by one or more of a battery, solar cell, wind, generator, power outlet, AC power source, DC power source, or other means.

The following are exemplary and non-limiting embodiments of the disclosure. The following exemplary embodiments are provided to further illustrate the principles disclosed herein and not to limit the disclosed principles.

Example 1 relates to a reflective image display, including: a front panel having a front panel; a front electrode formed on the plurality of front plates; a back plane positioned to form a gap with the front electrode, the back plane having a back electrode with a plurality of pixels, each pixel further comprising: memory circuitry (circuitry) to store bit values, and ink driver circuitry configured to operate at approximately 0.1V to 10V.

Example 2 relates to the reflective image display of example 1, wherein the reflective image display is a Total Internal Reflection (TIR) display.

Example 3 is directed to the reflective image display of example 1, wherein the ink driver circuitry is configured to operate at about 1V to 10V.

Example 4 is directed to the reflective image display of example 1, wherein the ink driver circuitry is configured to operate at about 0.1V to 5V.

Example 5 is directed to the reflective image display of example 1, further comprising a medium and a plurality of microcapsules located in the gap.

Example 6 relates to the reflective image display of example 5, wherein each microcapsule further comprises a plurality of electrophoretically mobile particles.

Example 7 is directed to the reflective image display of example 5, wherein each microcapsule further comprises a first set of electrophoretically mobile particles and a second set of electrophoretically mobile particles.

Example 8 is directed to the reflective image display of example 1, further comprising a medium and a plurality of microcups located in the gap, wherein each microcup further comprises a plurality of electrophoretically mobile particles.

Example 9 relates to the display of example 8, wherein each microcup further comprises a first set of electrophoretically mobile particles and a second set of electrophoretically mobile particles.

Example 10 is directed to the reflective image display of example 1, wherein the memory circuitry further comprises one or more Random Access Memories (RAMs).

Example 11 relates to a Total Internal Reflection (TIR) image display device, including: a front panel having a front panel, the front panel further comprising a plurality of hemispherical protrusions; a front electrode formed on the plurality of hemispherical protrusions; a back plane positioned to form a gap with the front electrode, the back plane having a back electrode with a plurality of pixels, each pixel further comprising: memory circuitry to store bit values, and ink driver circuitry configured to operate at approximately 0.1V to 10V.

Example 12 relates to the TIR image display apparatus of example 11, wherein the ink driver circuitry is configured to operate at approximately 1V to 10V.

Example 13 is directed to the TIR image display apparatus of example 11, wherein the ink driver circuitry is configured to operate at approximately 0.1V to 5V.

Example 14 relates to the TIR image display device of example 11, further comprising a medium and a plurality of electrophoretically mobile particles disposed in the gap.

Example 15 is directed to the TIR image display device of example 11, further comprising one microcapsule or one microcup positioned in the gap, wherein each microcapsule or microcup further comprises a plurality of electrophoretically mobile particles.

Example 16 relates to the TIR image display device of example 11, wherein the memory circuitry further comprises one or more Random Access Memories (RAMs).

Example 17 relates to the TIR image display of example 11, wherein the pixel unit comprises a red sub-pixel, a green sub-pixel, and a blue sub-pixel.

Example 18 relates to the TIR image display apparatus of example 11, further comprising an ambient light sensor in communication with the front light controller, the ambient light sensor configured to detect ambient light, and the front light sensor configured to direct the auxiliary light source to direct light to the front panel.

Example 19 is directed to the TIR image display apparatus of example 11, further comprising a waveguide formed on the front plate, the waveguide configured to receive light from the auxiliary light source in response to a change in ambient light conditions.

While the principles of the present disclosure have been illustrated with respect to the exemplary embodiments shown herein, the principles of the present disclosure are not limited thereto and include any modifications, variations, or permutations thereof.

Claims

1. A reflective image display, comprising:

a front panel having a front panel;

a front electrode formed on a plurality of the front plates;

a back plane positioned to form a gap with the front electrode, the back plane having a back electrode with a plurality of pixels, each pixel further comprising:

memory circuitry for storing bit values, an

Ink driver circuitry configured to operate at approximately 0.1V to 10V.

2. A reflective image display according to claim 1, wherein said reflective image display is a total internal reflection display.

3. The reflective image display of claim 1, wherein the ink driver circuitry is configured to operate at approximately 1-10V.

4. The reflective image display of claim 1, wherein the ink driver circuitry is configured to operate at approximately 0.1-5V.

5. A reflective image display according to claim 1, further comprising a medium and a plurality of microcapsules in said gap.

6. A reflective image display according to claim 5, wherein each microcapsule further comprises a plurality of electrophoretically mobile particles.

7. A reflective image display according to claim 5 wherein each microcapsule further comprises a first set of electrophoretically mobile particles and a second set of electrophoretically mobile particles.

8. A reflective image display according to claim 1 further comprising a medium and a plurality of microcups located in said gap, wherein each microcup further comprises a plurality of electrophoretically mobile particles.

9. A reflective image display according to claim 8 wherein each microcup further comprises a first set of electrophoretically mobile particles and a second set of electrophoretically mobile particles.

10. A reflective image display according to claim 1, wherein said memory circuitry further comprises one or more random access memories.

11. A total internal reflection, TIR, image display device, comprising:

a front panel having a front panel, the front panel further comprising a plurality of hemispherical protrusions;

a front electrode formed on the plurality of hemispherical protrusions;

memory circuitry for storing bit values, an

Ink driver circuitry configured to operate at approximately 0.1V to 10V.

12. The TIR image display apparatus of claim 11, wherein said ink driver circuitry is configured to operate at approximately 1 to 10V.

13. The TIR image display apparatus of claim 11, wherein said ink driver circuitry is configured to operate at approximately 0.1V to 5V.

14. The TIR image display of claim 11 further comprising a medium and a plurality of electrophoretically mobile particles disposed in said gap.

15. The TIR image display of claim 11 further comprising one microcapsule or one microcup positioned in said gap, wherein each microcapsule or microcup further comprises a plurality of electrophoretically mobile particles.

16. The TIR image display of claim 11, wherein said memory circuitry further comprises one or more random access memories.

17. The TIR image display of claim 11, wherein said pixel unit comprises a red sub-pixel, a green sub-pixel and a blue sub-pixel.

18. The TIR image display of claim 11, further comprising an ambient light sensor in communication with a front light controller, the ambient light sensor configured to detect ambient light, and the front light sensor configured to direct an auxiliary light source to direct light to the front panel.

19. The TIR image display apparatus of claim 11, further comprising a waveguide formed on the front plate, the waveguide configured to receive light rays from an auxiliary light source in response to a change in ambient light conditions.