WO2017003939A1 - Système et procédé d'attaque de dispositif d'affichage à électromouillage - Google Patents

Système et procédé d'attaque de dispositif d'affichage à électromouillage Download PDF

Info

Publication number
WO2017003939A1
WO2017003939A1 PCT/US2016/039612 US2016039612W WO2017003939A1 WO 2017003939 A1 WO2017003939 A1 WO 2017003939A1 US 2016039612 W US2016039612 W US 2016039612W WO 2017003939 A1 WO2017003939 A1 WO 2017003939A1
Authority
WO
WIPO (PCT)
Prior art keywords
sub
pixel
reflectance value
reflectance
value
Prior art date
Application number
PCT/US2016/039612
Other languages
English (en)
Inventor
Petrus Maria De Greef
Original Assignee
Amazon Technologies, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US14/754,532 external-priority patent/US9728143B2/en
Priority claimed from US14/754,501 external-priority patent/US9865200B2/en
Application filed by Amazon Technologies, Inc. filed Critical Amazon Technologies, Inc.
Publication of WO2017003939A1 publication Critical patent/WO2017003939A1/fr

Links

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3433—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices
    • G09G3/348—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices based on the deformation of a fluid drop, e.g. electrowetting
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0243—Details of the generation of driving signals
    • G09G2310/0251—Precharge or discharge of pixel before applying new pixel voltage
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0233—Improving the luminance or brightness uniformity across the screen

Definitions

  • Electronic displays are found in numerous types of electronic devices including, without limitation, electronic book (“eBook”) readers, mobile phones, laptop computers, desktop computers, televisions, appliances, automotive electronics, and augmented reality devices.
  • Electronic displays may present various types of information, such as user interfaces, device operational status, digital content items, and the like, depending on the kind and purpose of the associated device.
  • the appearance and quality of a display may affect a user's experience with the electronic device and the content presented thereon. Accordingly, enhancing user experience and satisfaction continues to be a priority.
  • increased multimedia use imposes high demands on designing, packaging, and fabricating display devices, as content available for mobile use becomes more extensive and device portability continues to be a high priority to the consumer.
  • An electrowetting display includes an array of pixels individually bordered by pixel walls that retain liquid, such as an opaque oil, for example. Light transmission through each pixel is adjustable by electronically controlling a position of the liquid in the pixel.
  • FIGS. 1 A and IB illustrate a cross-section of a portion of an
  • electrowetting display device according to various embodiments.
  • FIG. 2 illustrates a top view of the electrowetting pixels of FIGS. 1 A and
  • IB mostly exposed by an electrowetting fluid, according to various embodiments.
  • FIG. 3 is a block diagram of an example embodiment of an electrowetting display driving system, including a control system of the electrowetting display device.
  • FIG. 4 is a graph illustrating a reflectance hysteresis effect for an average sub-pixel within an electrowetting display device.
  • FIG. 5 depicts graphically a method for predictably setting the reflectance of an electrowetting sub-pixel.
  • FIG. 6 is a flowchart illustrating steps of an example method for setting the reflectance of a sub-pixel in a display device.
  • FIG. 7 depicts a plurality of different sub-pixels that may be part of a display.
  • FIG. 8 depicts graphically an example method for dithering reflectance values for an open electrowetting sub-pixel.
  • FIG. 9 is a flowchart depicting an example method for dithering reflectance values in an open electrowetting sub-pixel.
  • FIG. 10 depicts a plurality of electrowetting sub-pixels within a display in which reflectance values for a number of the electrowetting sub-pixels are dithered.
  • FIG. 11 depicts graphically an example method for dithering reflectance values for a closed electrowetting sub-pixel.
  • FIG. 12 is a flowchart depicting an example method for dithering reflectance values in a closed electrowetting sub-pixel.
  • FIG. 13 is a flowchart illustrating an example method for applying by a display controller dithering techniques to electrowetting sub-pixels of a display.
  • FIG. 14 illustrates an example electronic device that may incorporate a display device, according to various embodiments.
  • electronic devices include electrowetting displays for presenting content and other information.
  • the electronic devices may include one or more components associated with the electrowetting display, such as a touch sensor component layered atop the electrowetting display for detecting touch inputs, a front light or back light component for lighting the electrowetting display, and/or a cover layer component, which may include antiglare properties, antireflective properties, anti-fingerprint properties, anti- cracking properties, and the like.
  • An electrowetting pixel is defined by a number of pixel walls that surround or are otherwise associated with at least a portion of the electrowetting pixel.
  • the pixel walls form a structure that is configured to contain at least a portion of a first liquid, such as an opaque oil.
  • Light transmission through the electrowetting pixel can be controlled by an application of an electric potential to the electrowetting pixel, which results in a movement of a second liquid, such as an electrolyte solution, into the electrowetting pixel, thereby displacing the first liquid.
  • the electrowetting pixel When the electrowetting pixel is in a rest state (i.e., with no electric potential applied), the opaque oil is distributed throughout the pixel. The oil absorbs light and the pixel in this conditional appears black. But when the electric potential is applied, the oil is displaced to one side of the pixel. Light can then enter the pixel striking a reflective surface. The light then reflects out of the pixel, causing the pixel to appear white to an observer. If the reflective surface only reflects a portion of the light spectrum or if light filters are incorporated into the pixel structure, the pixel may appear to have color.
  • the degree to which the oil is displaced from its resting position affects the overall reflectance of the pixel - the pixel's capability to reflect light - and, thereby, the pixel's appearance.
  • the driving voltage for a particular pixel results in a predictable reflectance value for that pixel, enabling the overall reflectance of the display device to be precisely and predictably controlled.
  • the resulting reflectance for that pixel depends upon the state of the pixel before the driving voltage was applied. If, for example, the pixel was already open when driven at the driving voltage, the resulting reflectance may be different than if the pixel was closed before the driving voltage was applied.
  • the oil movement within a pixel exhibits hysteresis, making oil position difficult to accurately predict based upon driving voltage.
  • This attribute of electrowetting display pixels also make reflectance difficult to control, resulting in degradations in overall image quality and/or image artifacts.
  • the disclosed system and methods therefore, provide electrowetting display pixel driving schemes arranged to minimize or reduce pixel reflectance uncertainty resulting from oil movement hysteresis.
  • the driving scheme when setting the reflectance of a pixel to a particular target reflectance, involves a preliminary step, in which the pixel is first driven with a driving voltage putting the pixel in a known condition. With the pixel in the known condition, changes to driving voltage result in known, predictable changes to pixel reflectance and the reflectance of the pixel can confidently be set to the target reflectance.
  • a display controller utilizes dithering algorithms that avoid setting the reflectance of individual pixels to values that are difficult to predict, while still achieving a target average reflectance level over groups of pixels.
  • a display device such as an electrowetting display device, may be a transmissive, reflective or transflective display that generally includes an array of pixels, which comprise a number of sub-pixels, configured to be operated by an active matrix addressing scheme. For example, rows and columns of electrowetting pixels (and their sub-pixels) are operated by controlling voltage levels on a plurality of source lines and gate lines. In this fashion, the display device may produce an image by selecting particular pixels or sub-pixels to transmit, reflect or block light. Sub- pixels are addressed (e.g., selected) via rows and columns of the source lines and the gate lines that are electrically connected to transistors (e.g., used as switches) included in each sub-pixel.
  • transistors e.g., used as switches
  • a pixel may, unless otherwise specified, be made up of two or more sub-pixels of an electrowetting display device.
  • Such a pixel or sub-pixel may be the smallest light transmissive, reflective or transflective pixel of a display that is individually operable to directly control an amount of light transmission through or reflection from the pixel.
  • a pixel may comprise a red sub-pixel, a green sub-pixel, and a blue sub-pixel.
  • a pixel may be a smallest component, e.g., the pixel does not include any sub-pixels.
  • Electrowetting displays include an array of pixels and sub-pixels sandwiched between two support plates, such as a bottom support plate and a top support plate.
  • a bottom support plate in cooperation with a top support plate may contain sub-pixels that include electrowetting oil, electrolyte solution and pixel walls between the support plates.
  • Support plates may include glass, plastic (e.g., a transparent thermoplastic such as a poly(methyl methacrylate) (PMMA) or other acrylic), or other transparent material and may be made of a rigid material or a flexible material, for example.
  • Sub-pixels include various layers of materials built upon a bottom support plate.
  • One example layer is an amorphous fluoropolymer (AF) with hydrophobic behavior, around portions of which pixel walls are built.
  • AF amorphous fluoropolymer
  • example embodiments include, but are not limited to, reflective electrowetting displays that include a clear or transparent top support plate and a bottom support plate, which need not be transparent.
  • the clear top support plate may comprise glass or any of a number of transparent materials, such as transparent plastic, quartz, and semiconductors, for example, and claimed subject matter is not limited in this respect.
  • Top and bottom as used herein to identify the support plates of an electrowetting display do not necessarily refer to a direction referenced to gravity or to a viewing side of the electrowetting display.
  • the top support plate is that through which viewing of pixels of a (reflective) electrowetting display occurs.
  • a reflective electrowetting display comprises an array of pixels and sub-pixels sandwiched between a bottom support plate and a top support plate.
  • the bottom support plate may be opaque while the top support plate is transparent.
  • describing a pixel, sub-pixel, or material as being “transparent” means that the pixel or material may transmit a relatively large fraction of the light incident upon it.
  • a transparent material or layer may transmit more than 70% or 80% of the light impinging on its surface, though claimed subject matter is not limited in this respect.
  • Sub-pixel walls retain at least a first fluid which is electrically non- conductive, such as an opaque or colored oil, in the individual pixels.
  • a cavity formed between the support plates is filled with the first fluid (e.g., retained by pixel walls) and a second fluid (e.g., considered to be an electrolyte solution) that is electrically conductive or polar and may be a water or a salt solution such as a solution of potassium chloride water.
  • the second fluid may be transparent, but may be colored, or light-absorbing. The second fluid is immiscible with the first fluid.
  • Individual reflective electrowetting sub-pixels may include a reflective layer on the bottom support plate of the electrowetting sub-pixel, a transparent electrode layer adjacent to the reflective layer, and a hydrophobic layer on the electrode layer. Pixel walls of each sub-pixel, the hydrophobic layer, and the transparent top support plate at least partially enclose a liquid region that includes an electrolyte solution and an opaque liquid, which is immiscible with the electrolyte solution.
  • An "opaque" liquid as described herein, is used to describe a liquid that appears black to an observer.
  • an opaque liquid strongly absorbs a broad spectrum of wavelengths (e.g., including those of red, green and blue light) in the visible region of electromagnetic radiation.
  • the opaque liquid is a nonpolar electrowetting oil.
  • the opaque liquid is disposed in the liquid region.
  • a coverage area of the opaque liquid on the bottom hydrophobic layer is electrically adjustable to affect the amount of light incident on the reflective electrowetting display that reaches the reflective material at the bottom of each pixel.
  • spacers and edge seals may also be located between the two support plates.
  • the support plates may comprise any of a number of materials, such as plastic, glass, quartz, and semiconducting materials, for example, and claimed subject matter is not limited in this respect.
  • Spacers and edge seals which mechanically connect the first support plate with the second overlying support plate, or which form a separation between the first support plate and the second support plate, contribute to mechanical integrity of the electrowetting display.
  • Edge seals for example, being disposed along a periphery of an array of electrowetting pixels, may contribute to retaining fluids (e.g., the first and second fluids) between the first support plate and the second overlying support plate.
  • Spacers can be at least partially transparent so as to not hinder throughput of light in the electrowetting display. The transparency of spacers may at least partially depend on the refractive index of the spacer material, which can be similar to or the same as the refractive indices of surrounding media. Spacers may also be chemically inert to surrounding media.
  • a display device as described herein may comprise a portion of a system that includes one or more processors and one or more computer memories, which may reside on a control board, for example.
  • Display software may be stored on the one or more memories and may be operable with the one or more processors to modulate light that is received from an outside source (e.g., ambient room light) or out-coupled from a lightguide of the display device.
  • display software may include code executable by a processor to modulate optical properties of individual pixels of the electrowetting display based, at least in part, on electronic signals representative of image and/or video data. The code may cause the processor to modulate the optical properties of pixels by controlling electrical signals (e.g., voltages, currents, and fields) on, over, and/or in layers of the electrowetting display.
  • FIG. 1 A is a cross-section of a portion of an example reflective electrowetting display device 10 illustrating several electrowetting sub-pixels 100 taken along sectional line 1-1 of FIG. 2.
  • FIG. IB shows the same cross-sectional view as FIG. 1 A in which an electric potential has been applied to one of the electrowetting sub-pixels 100 causing displacement of a first fluid disposed therein, as described below.
  • FIG. 2 shows a top view of electrowetting sub-pixels 100 formed over a bottom support plate 104.
  • Electrowetting display device 10 may include any number (usually a very large number, such as thousands or millions) of electrowetting sub-pixels 100.
  • An electrode layer 102 is formed on a bottom support plate 104.
  • electrode layer 102 may be connected to any number of transistors, such as thin film transistors (TFTs) (not shown), that are switched to either select or deselect electrowetting sub-pixels 100 using active matrix addressing, for example.
  • TFTs thin film transistors
  • a TFT is a particular type of field-effect transistor that includes thin films of an active semiconductor layer as well as a dielectric layer and metallic contacts over a supporting (but non-conducting) substrate, which may be glass or any of a number of other suitable transparent or non-transparent materials, for example.
  • a dielectric barrier layer 106 may at least partially separate electrode layer 102 from a hydrophobic layer 107, such as an amorphous fluoropolymer layer for example, also formed on bottom support plate 104. Such separation may, among other things, prevent electrolysis occurring through hydrophobic layer 107.
  • Barrier layer 106 may be formed from various materials including organic/inorganic multilayer stacks or silicon dioxide (Si0 2 ) and polyimide layers. When constructed using a combination of Si0 2 and polyimide layers, the Si0 2 layer may have a thickness of 200 nanometers and a dielectric constant of 3.9, while the polyimide layer may have a thickness of 105 nanometers and a dielectric constant of 2.9.
  • hydrophobic layer 107 is an amorphous fluoropolymer layer including any suitable fluoropolymer(s), such as AF1600, produced by DuPont, based in Wilmington, Delaware. Hydrophobic layer 107 may also include suitable materials that affect wettability of an adjacent material, for example.
  • Sub-pixel walls 108 form a patterned electrowetting pixel grid on hydrophobic layer 107.
  • Sub-pixel walls 108 may comprise a photoresist material such as, for example, epoxy-based negative photoresist SU-8.
  • the patterned electrowetting sub-pixel grid comprises rows and columns that form an array of electrowetting sub- pixels.
  • an electrowetting sub-pixel may have a width and a length in a range of about 50 to 500 micrometers.
  • a first fluid 110 which may have a thickness (e.g., a depth) in a range of about 1 to 10 micrometers, for example, overlays hydrophobic layer 107.
  • First fluid 110 is partitioned by sub-pixel walls 108 of the patterned electrowetting sub-pixel grid.
  • a second fluid 114 such as an electrolyte solution, overlays first fluid 110 and sub-pixel walls 108 of the patterned electrowetting sub-pixel grid.
  • Second fluid 114 may be electrically conductive and/or polar.
  • second fluid 114 may be, for example, a water solution or a salt solution such as potassium chloride water.
  • First fluid 110 is immiscible with second fluid 114.
  • a support plate 116 covers second fluid 114 and a spacer 118 to maintain second fluid 114 over the electrowetting sub-pixel array.
  • spacer 118 extends to support plate 116 and may rest upon a top surface of one or more of the sub-pixel walls 108. In alternative embodiments, spacer 118 does not rest on sub- pixel wall 108 but is substantially aligned with sub-pixel wall 108. This arrangement may allow spacer 118 to come into contact with sub-pixel wall 108 upon a sufficient pressure or force being applied to support plate 116. Multiple spacers 118 may be interspersed throughout the array of sub-pixels 100.
  • Support plate 116 may be made of glass or polymer and may be rigid or flexible, for example. In some embodiments, TFTs are fabricated onto support plate 116.
  • a voltage applied across, among other things, second fluid 114 and electrode layer 102 of individual electrowetting pixels may control transmittance or reflectance of the individual electrowetting pixels.
  • the reflective electrowetting display device 10 has a viewing side 120 on which an image formed by the electrowetting display device 10 may be viewed, and an opposing rear side 122. Support plate 116 faces viewing side 120 and bottom support plate 104 faces rear side 122.
  • the reflective electrowetting display device 10 may be a segmented display type in which the image is built of segments. The segments may be switched simultaneously or separately. Each segment includes one electrowetting sub-pixel 100 or a number of electrowetting sub-pixels 100 that may be adjacent or distant from one another. In some cases, adjacent electrowetting sub- pixels 100 may be sub-pixels 100 that are next to one another with no other intervening sub-pixel 100. In other cases, adjacent electrowetting sub-pixels 100 may be sub-pixels 100 that are located in adjacent pixels. Adjacent sub-pixels 100 may be defined as sub-pixels of the same color that are located in adjacent pixels.
  • Electrowetting sub-pixels 100 included in one segment are switched simultaneously, for example.
  • the electrowetting display device 10 may also be an active matrix driven display type or a passive matrix driven display, for example.
  • second fluid 114 is immiscible with first fluid 110.
  • Second fluid 114 is electrically conductive and/or polar, and may be water or a salt solution such as a solution of potassium chloride in a mixture of water and ethyl alcohol, for example.
  • second fluid 114 is transparent, but may be colored or absorbing.
  • First fluid 110 is electrically non- conductive and may for instance be an alkane like hexadecane or (silicone) oil.
  • Hydrophobic layer 107 is arranged on bottom support plate 104 to create an electrowetting surface area.
  • the hydrophobic character of hydrophobic layer 107 causes first fluid 110 to adhere preferentially to hydrophobic layer 107 because first fluid 110 has a higher wettability with respect to the surface of hydrophobic layer 107 than second fluid 114 in the absence of a voltage.
  • Wettability relates to the relative affinity of a fluid for the surface of a solid. Wettability increases with increasing affinity, and it may be measured by the contact angle formed between the fluid and the solid and measured internal to the fluid of interest. For example, such a contact angle may increase from relative non-wettability of more than 90° to complete wettability at 0°, in which case the fluid tends to form a film on the surface of the solid.
  • First fluid 110 absorbs light within at least a portion of the optical spectrum.
  • First fluid 110 may be transmissive for light within a portion of the optical spectrum, forming a color filter.
  • the fluid may be colored by addition of pigment particles or dye, for example.
  • first fluid 110 may be black (e.g., absorbing substantially all light within the optical spectrum) or reflecting.
  • Hydrophobic layer 107 may be transparent or reflective. A reflective layer may reflect light within the entire visible spectrum, making the layer appear white, or reflect a portion of light within the visible spectrum, making the layer have a color.
  • electrowetting sub-pixel 100 will enter into an active or open state. Electrostatic forces will move second fluid 114 toward electrode layer 102 within the active sub- pixel as hydrophobic layer 107 formed within the active electrowetting sub-pixel 100 becomes hydrophilic, thereby displacing first fluid 110 from that area of hydrophobic layer 107 to sub-pixel walls 108 surrounding the area of hydrophobic layer 107, to a droplet-like form. Such displacing action uncovers first fluid 110 from the surface of hydrophobic layer 107 of electrowetting sub-pixel 100.
  • FIG. IB shows one of electrowetting sub-pixels 100 in an active state.
  • second fluid 114 is attracted towards electrode layer 102 displacing first fluid 110 within the activated electrowetting sub-pixel 100.
  • first fluid 110 is displaced and moves towards a sub-pixel wall 108 of the activated sub-pixel 100.
  • first fluid 110 of sub-pixel 100a has formed a droplet as a result of an electric potential being applied to sub-pixel 100a.
  • electrowetting sub-pixel 100a After activation, when the voltage across electrowetting sub-pixel 100a is returned to an inactive signal level of zero or a value near to zero, electrowetting sub-pixel 100a will return to an inactive or closed state, where first fluid 110 flows back to cover hydrophobic layer 107. In this way, first fluid 110 forms an electrically controllable optical switch in each electrowetting sub-pixel 100.
  • FIG. 3 shows a block diagram of an example embodiment of an electrowetting display driving system 300, including a control system of the display device.
  • Display driving system 300 can be of the so-called direct drive type and may be in the form of an integrated circuit adhered to bottom support plate 104.
  • Display driving system 300 includes control logic and switching logic, and is connected to the display by means of electrode signal lines 302 and a common signal line 304.
  • Each electrode signal line 302 connects an output from display driving system 300 to a different electrode within each sub-pixel 100, respectively.
  • Common signal line 304 is connected to second fluid 114 through an electrode.
  • display driving system 300 can be instructed with data so as to determine which sub-pixels 100 should be in an active or open state and which sub-pixels 100 should be in an inactive or closed state at any moment of time. In this manner, display driving system 300 can determine a target reflectance value for each sub-pixel 100 within the display.
  • the data specifying the target reflectance value for each sub-pixel 100 may explicitly set forth a particular reflectance value or, in some embodiments, may include data from which a target reflectance value or driving voltage can be determined. For example, the data may specify a particular percentage by which a particular sub-pixel should be opened, or a particular driving voltage for the sub-pixel.
  • the data may also specify a particular brightness or color for a sub-pixel or any other data indicating how a particular sub-pixel within the display should appear. Controller 308 can then convert (if necessary) that data into target reflectance values for each sub-pixel. Once a target reflectance value is determined for a particular sub-pixel, controller 308 sets the reflectance value of the sub-pixel to that target reflectance value by converting the reflectance value into a corresponding driving voltage to be subjected to the electrode of the sub-pixel. That driving voltage is then applied to the appropriate electrode signal line 302.
  • the reflectance value of a particular sub-pixel may relate to or provide some indication of the actual reflectance of the sub-pixel.
  • the reflectance value is not necessarily a measure of the sub-pixel's actual reflectance, but is a value that is intended to scale with or relate to the sub-pixel's actual reflectance.
  • the reflectance value may be expressed as a numerical value utilized by display driving system 300 to select an appropriate driving voltage for a sub-pixel.
  • Reflectance values may include numerical values between 0 and 100, where 0 represents a minimum reflectance of a pixel and 100 represents a maximum reflectance. In other embodiments, such a scale may include more or fewer values.
  • the reflectance value may be a numerical value equal to or easily translated into a corresponding driving voltage, such as an actual voltage value, a scaled voltage value, a video level, or other similar values.
  • Electrowetting display driving system 300 as shown in FIG. 3 includes a display controller 308, e.g., a microcontroller, receiving input data from the input data lines 306 relating to the image to be displayed.
  • Display controller 308, being in this embodiment the control system, is configured to apply a voltage to the first electrode to establish a particular display state (i.e., reflectance value) for a sub-pixel 100.
  • the microcontroller controls a timing and/or a signal level of at least one signal level for a sub-pixel 100.
  • the output of display controller 308 is connected to the data input of a signal distributor and data output latch 310.
  • the signal distributor and data output latch 310 distributes incoming data over a plurality of outputs connected to the display device, via drivers in certain embodiments.
  • the signal distributor and data output latch 310 cause data input indicating that a certain sub-pixel 100 is to be set in a specific display state to be sent to the output connected to sub-pixel 100.
  • the distributor and data output latch 310 may be a shift register. The input data is clocked into the shift register and at receipt of a latch pulse the content of the shift register is copied to the distributor and data output latch 310.
  • the distributor and data output latch 310 has one or more outputs, connected to a driver assembly 312.
  • the outputs of the distributor and data output latch 310 are connected to the inputs of one or more driver stages 314 within the electrowetting display driving system 300.
  • the outputs of each driver stage 314 are connected through electrode signal lines 302 and common signal line 304 to a corresponding sub-pixel 100.
  • a driver stage 314 will output a voltage of the signal level set by display controller 308 to set one of sub-pixels 100 to a corresponding display state having a target reflectance level.
  • memory 316 may also store data that maps a particular driving voltage for a sub-pixel to a corresponding reflectance value and vice versa.
  • the data may be stored as one or more curves depicting the relationship between driving voltage and reflectance value, or a number of discrete data points that map a driving voltage to a reflectance value and vice versa.
  • display controller 308 can use the data mapping driving voltage to reflectance value to identify a corresponding driving voltage. The sub-pixel can then be driven with that driving voltage.
  • memory 316 may store two sets of data that map particular reflectance values to driving voltages for sub-pixels in both open and closed states for various ranges of driving voltage.
  • the data may be stored or represented in memory 316 in any suitable manner including curvilinear functions or a series of discrete data points that relate different reflectance values to particular driving voltages for sub-pixels in open and closed states.
  • display controller 308 can then translate a particular target reflectance value for a sub-pixel to a corresponding driving voltage based upon the sub-pixel's current state.
  • display controller 308 may include or be connected to memory 316 configured to store a status of one or more sub-pixels 100 in the display device.
  • memory 316 may store an indication of whether a particular sub-pixel 100 is currently in an open or closed state.
  • display controller 308 can update one or more entries in memory 316 to indicate the sub- pixel's current state.
  • a sub-pixel's reflectance can depend upon the prior state of the sub-pixel (e.g., whether the sub-pixel was in an open or closed state before being driven at the given driving voltage)
  • the sub-pixel state data stored in memory 316 can be utilized, as described herein, to more accurately control sub-pixel reflectance.
  • the sub-pixel state data may be stored within memory 316 in any suitable fashion. For example, within memory 316, a flag may be set for each sub-pixel within the display device indicating whether the sub-pixel is currently in an open state or a closed state. Alternatively, the sub-pixel state data may be stored in a bitmap, where the bitmap is a two-dimensional array of bits having a number of bits equal to the number of sub-pixels in the display.
  • Each bit represents a particular sub-pixel and can then be toggled between different values (e.g., '0' and T) to indicate the current state of a corresponding sub-pixel (e.g., where a value of '0' represents the pixel being in a closed state and a value of T represents the pixel being in an open state).
  • FIG. 4 is a graph illustrating this hysteresis effect for an average sub-pixel within a display.
  • the horizontal axis represents a sub-pixel's driving voltage
  • the vertical axis represents the sub-pixel's actual reflectance.
  • the graph shows two curves. The first rising curve shows the average sub-pixel's reflectance versus voltage when the sub-pixel is transitioned from a closed state to an open state. The falling curve shows the average sub-pixel's reflectance versus voltage when the sub-pixel is transitioned from an open state to a closed state.
  • the sub-pixel's reflectance value shows relatively significant hysteresis spanning 25% of the driving voltage range and 60% of the reflectance range.
  • the closed-state sub-pixels When the driving voltage for a sub-pixel reaches or exceeds V open high, the closed-state sub-pixels have been forced open and enter an open state. Once the sub- pixels have entered the open state, variations in the driving voltage of the open-state sub-pixels will cause the reflectance of those sub-pixels to move along the open-to- closed curve of FIG. 4. As such, a sub-pixel that is in an open state is not necessary 100%) open. As illustrated by FIG. 4, as the driving voltage of an open-state sub-pixel is varied, the reflectance of the open-state sub-pixel travels along the open-to-closed curve and, as such, the reflectance and the degree to which the sub-pixel is open, will vary.
  • R op en high refers to a lowest reflectance level above which a closed-state sub-pixel transitions to an open-state sub-pixel from a closed-state sub-pixel.
  • Ro pe n high is a reflectance level corresponding to a driving voltage level above which a closed sub-pixel has a high probability (e.g., greater than 95%) of opening when driven to this driving voltage for at least one addressing cycle.
  • an addressing cycle may refer to a single operating cycle of display controller 308 analyzing data 306 to determine a target reflectance value for a sub-pixel, converting that target reflectance value to a corresponding driving voltage (if necessary), and subjecting the sub-pixel to that driving voltage until controller 308 again reads data 306 to determine a new reflectance value.
  • the addressing cycle may occur every time new data is retrieved from data 306 by display controller 308. Consequently, the addressing cycle may be equal to the minimum amount of time between a sub-pixel being set to a first reflectance value and the sub-pixel being set to a second reflectance value.
  • the duration of an addressing cycle may change based upon the operation of display driving system 300 and so may not be a fixed period of time, but in various embodiments could be approximately 1/60 of a second.
  • R c i 0S e_high refers to a lowest reflectance above which an open state sub-pixel will remain open before closing to a minimum reflectance value. Or, alternatively, a highest reflectance below which an open sub- pixel will close.
  • Rciosejngh is a lowest reflectance corresponding to a lowest driving voltage level above which an open sub-pixel has a high probability (e.g., greater than 95%) of remaining open.
  • the average sub-pixel reflectance has a maximum value R ma x as all the sub-pixels are fully open.
  • V ma x For driving voltages above V c i ose high the reflectance of the sub-pixels is relative linear. But when the driving voltage decreases below V c i ose high along the open-to-closed curve, the average reflectance gradually starts to decrease faster, as some individual sub-pixels are closing to the reflection level R c i OS ejow, while others remain opened at the reflectance level close to R c i 0S e_high- In the mid point between V c i ose j ow and
  • the method disclosed herein provides for first driving a sub-pixel with a particular driving voltage configured to place the sub-pixel in a condition from which the target reflectance can be reliably achieved.
  • all sub-pixels in a display may be first driven to their fully-open condition (e.g., at a driving voltage greater than or equal to V ope n high)- This causes all sub-pixels to have an initial state of open (though in a real-world implementation sometimes fewer than all sub-pixels (e.g., 95%) will in fact be open at that driving voltage). Then, after all sub-pixels have been opened, the driving voltage applied to any of the sub-pixels of a display device is offset so that the minimum driving voltage is V c i ose high- This ensures that all sub-pixels in the display device are always operating in an at least partially-opened condition. By restricting the driving voltage in this manner, all sub-pixels will operate along the open-to-closed curve shown in FIG. 4, enabling predictable control over each sub-pixel's reflectance.
  • An alternative method therefore, enables the setting of a sub-pixel's reflectance in a predictable manner, but without negatively affecting the display's overall contrast ratio.
  • the method first determines the sub-pixel's current state (e.g., closed state or open state). Based upon the sub-pixel's current state as well as the target reflectance value for the sub- pixel, the method adjusts the sub-pixel's reflectance value either directly to the target reflectance value when the reflectance can be predictably set or through an
  • the sub-pixel can be reliably driven to any target reflectance value.
  • the target reflectance value is less than R ope n low, for example, the sub-pixel can simply be driven with a driving voltage corresponding to that target reflectance value.
  • the sub-pixel If, however, the sub-pixel is in a closed state (i.e., the sub-pixel's reflectance was recently less than R c i OS ejow), the sub-pixel cannot be reliably driven to a reflectance value below R op en high- This is because a sub-pixel operating on the closed-to-open curve of FIG. 4 (e.g., a sub-pixel with an initial starting state of closed) will exhibit uncontrolled or unpredictable opening at reflectance values below Ropen high- To mitigate this problem, the disclosed method first sets the reflectance value of the sub-pixel to an intermediate level that allows for the reflectance of the sub-pixel to be reliably set to levels below R ope n high-
  • FIG. 5 depicts the mapping between a particular reflectance value for a sub-pixel and the corresponding driving voltage based upon the sub-pixel's current state.
  • reflectance values depicted on the vertical axis will correspond, generally, to the actual reflectance of a sub-pixel set to that reflectance value.
  • a closed-state sub-pixel with an initial starting reflectance value of approximately R c i OS ejow (see point 502) is to be set to a target reflectance value R ta r g et between R c i 0S e_high and R ope n high (see point 504).
  • R ta r g et between R c i 0S e_high and R ope n high
  • the sub-pixel's reflectance value is set to a value greater than or equal to R ope n high with a corresponding driving voltage greater than or equal to V open high (see point 506).
  • the sub-pixel will be set to an open state.
  • the sub-pixel's reflectance value can then be set to the target value Rtarget, with a corresponding driving voltage of Vtarget (point 504) with the sub-pixel's reflectance behavior transitioning along the open-to-closed curve, resulting in the sub-pixel's reflectance being reliably set at point 504.
  • FIG. 6 is a flowchart illustrating the steps of an example method 600 for setting the reflectance of a sub-pixel in a display device corresponding to the illustration shown in FIG. 5.
  • the method 600 illustrated in FIG. 6 may be executed by a display controller (e.g., display controller 308) of the display device.
  • the display controller may be configured to process incoming graphical data to determine target reflectance values for a number of sub-pixels within the display device. Then, for each sub-pixel in the display, the display controller can implement the method illustrated in FIG. 6 to achieve the target reflectance value for each sub-pixel in the display.
  • the example method 600 of FIG. 6 enables the reflectance of a closed sub-pixel to be predictably set to a value less than Ro pe n high- Accordingly, in some embodiments, the method is only utilized to set the reflectance value of a pixel that is in a closed state.
  • step 602 the display controller determines a target reflectance value for a particular sub-pixel within the display.
  • the target reflectance value can be determined by any suitable method and may involve the analysis of video or other graphical data transmitted to the display controller.
  • step 604 the display controller determines whether the target reflectance value is greater than or equal to R ope n high- If so, the sub-pixel can be predictably driven to that reflectance value regardless of the pixel's initial state. As such, in step 606 the reflectance value of the sub-pixel is set to the target reflectance value.
  • the display controller determines whether the sub-pixel is in an open state. This may involve the display controller accessing a memory storing sub-pixel state information to determine the current open or closed state of the sub-pixel.
  • the controller may be configured to utilize a memory (e.g., memory 316 of FIG. 3) in which to store a current state of each sub-pixel in the display.
  • the controller may determine whether the current reflectance value of the sub- pixel is greater than or equal to R c i 0S e_high, which would indicate that the sub-pixel is in an open state.
  • the reflectance value of the sub-pixel can be set to values less than R ope n high because when the sub-pixel is driven with a driving voltage corresponding to the reflectance value, the sub-pixel will be operating along the open-to-closed curve shown in FIG. 4. Accordingly, method 600 moves to step 606 in which the reflectance value of the sub-pixel is set to the target reflectance value with an appropriate driving voltage.
  • step 608 determines whether the target reflectance value is greater than or equal to R c i 0S e_high- If so, in step 612 the reflectance value of the sub-pixel is set to a value greater than or equal to Ro pe n high- Step 612 may set the reflectance value of the sub-pixel to the value greater than Ropen high for at least a single address cycle (e.g., approximately 1/60 second) and ensures that the sub-pixel is in an open state prior to being set to the target reflectance value.
  • a single address cycle e.g., approximately 1/60 second
  • step 606 the reflectance value of the sub-pixel is set to the target reflectance value.
  • the target reflectance value is less than Rciosejngh, the target reflectance value cannot be accurately set because, as discussed above, the closing and opening behaviors or sub-pixels are difficult to predict at reflectance values between R c i OS ejow and R c i 0S e_high- Accordingly, in method 600, if the target reflectance value falls between Rci OS ejow and Rci 0S e_high, the reflectance value of the sub-pixel will instead be set to a different, predictable value of either Rci OS ejow or R c i 0S e_high- [0083] Accordingly, in step 614 the controller determines whether the target reflectance value is closer to R c i OS ejow or Rci 0S e_high- If closer to Rci OS ejow (i.e., the target reflectance value is less than R c i OS ejow + (Rciosejugh - R c
  • the sub-pixel's reflectance value is first set to a value greater than or equal to Ro pe n high in step 618 before being set to R c i 0S e_high in step 620.
  • the sub-pixel may be set to a value greater than or equal to R op en high for a single address cycle.
  • the display could exhibit periods of time with too much overall reflectance.
  • the display controller may be configured to undertake certain steps to prevent too much reflectance being generated within regions or areas of the display.
  • the display controller is configured to impose spatial limitations on the sub-pixels being driven to excessive reflectance values. This may involve, for example, defining a number of different regions covering the display and, within each region, limiting the number of sub-pixels driven to reflectance values greater than the target reflectance value to a particular threshold number. In certain circumstances (e.g., scene-changes within a video, or large changes in output that affect nearly all sub-pixels within the display), this restriction could be relaxed so that any number of sub-pixels within the display could be driven to reflectance values greater than their target reflectance values.
  • the display controller may be configured to compensate for the excessive reflectance of one sub-pixel by temporarily reducing the reflectance values of a number of other (e.g., adjacent) sub-pixels.
  • FIG. 7 depicts a number of different sub-pixels that may be part of a display.
  • the reflectance value of sub-pixel 702 is being determined according to method 600 of FIG. 6.
  • sub-pixel 702 To provide that the reflectance value of sub-pixel 702 can be reliably set to a target reflectance value that is below Ro pe n high, sub-pixel 702 is first set to a reflectance value above R ope n high- This can result in sub-pixel 702 temporarily having too much reflectance (i.e., a reflectance value greater that the target reflectance value). To compensate for the additional undesired reflectance of sub-pixel 702, the display controller may temporarily reduce the reflectance value of one or more adjacent sub-pixels 704.
  • the display controller can determine the amount of additional unwanted reflectance by determining the difference between the target reflectance value for sub-pixel 702 and Ro pe n high (i.e., the overdriven reflectance value of sub-pixel 702). The display controller can then divide that additional reflectance amount by the number of adjacent sub-pixels 704 and then reduce the reflectance value of each adjacent sub-pixel 704 by the result. In that case, the sum of the reductions in reflectance values over the adjacent sub-pixels 704 will offset the additional reflectance value of sub-pixel 702 while sub-pixel 702 is temporarily overdriven.
  • the reflectance value of adjacent sub-pixels 704 may only be reduced for the period of time during which sub-pixel 702 is overdriven or may be reduced for some other amount of time. After sub-pixel 702 is set to the target reflectance value, adjacent sub-pixels 704 could be returned to their original reflectance values.
  • the display controller may only reduce the reflectance values for adjacent sub-pixels 704 that will not be closed if their reflectance value should be reduced.
  • the sub-pixel's driving regime may be configured to avoid reflectance values that correspond to driving voltages between V cloS e_iow and V c i ose high as those driving voltages result in unpredictable reflectance.
  • the display controller may implement a dithering approach that relies upon the average reflectance of a group of sub-pixels to achieve particular target reflectance values.
  • the display controller may combine a number of sub-pixels with reflectance values of R c i ose low with another number of pixels with reflectance values of R c i ose high to achieve a target average reflectance for the group of sub-pixels.
  • the average reflectance of the sub-pixels will be observed by a human spectator because the human visual system tends to apply both spatial and temporal filtering to collections of pixels and may be at levels between R c i OS e_iow and Rci 0S e_high- [0092]
  • the dithering approach is depicted in FIG. 8.
  • the horizontal axis represents driving voltage
  • the vertical axis represents the reflectance value of the sub-pixel.
  • FIG. 8 depicts the mapping between a particular reflectance value for a sub-pixel and the corresponding driving voltage based upon the sub-pixel's current state.
  • reflectance values depicted on the vertical axis will correspond, generally, to the actual reflectance of a sub-pixel set to that reflectance value.
  • the sub-pixel can be reliably driven to any reflectance value along the curve, with the exception of reflectance values between R c i OS ejow and R c i 0S e_high- For those reflectance values, the sub-pixel will instead be driven to the nearest reflectance value that results in a predictable reflectance that falls outside those levels. This will result in an error in that sub-pixel's reflectance from the target reflectance value. To compensate, the reflectance values of surrounding sub-pixels are adjusted either slightly higher or lower, as needed, to offset the error.
  • a specific dithering approach such as Floyd- Steinberg dithering, may be utilized to implement this reflectance dithering.
  • error diffusion may be utilized to distribute the reflectance error resulting from the reflectance value dithering of a single sub-pixel to other sub-pixels within the display to achieve a target average reflectance level.
  • the reflectance error is only distributed to other sub-pixels of the same color.
  • the accumulated error resulting from this reflectance value dithering can be referred to as quantization error as it results from the quantization of a reflectance value of a sub- pixel from a value between R c i OS ejow and R c i 0S e_high to the specific values of either
  • FIG. 9 is a flowchart showing an example method 900 that may be performed by a display controller to implement the disclosed dithering scheme. Because the dithering method controls reflectance for sub-pixels transitioning along the open-to-closed curve of FIG. 4, method 900 may only be applied to pixels that have an initial state of open. Method 900 may be implemented for each sub-pixel within a display, with the display controller implementing method 900 for a first sub- pixel in an open state and then moving to a next sub-pixel in an open state and re- executing method 900. In this manner, the display controller may iterate through each open state sub-pixel in the display, executing method 900 once for each open state sub-pixel. When method 900 has been executed for all open state sub-pixels in the display, the display controller will repeat the process again for each open state sub- pixel.
  • the display controller can iterate through the display's open sub-pixels in any suitable manner.
  • the display controller may iterate through sub-pixels from left to right, and top to bottom.
  • the display controller may iterate through each row of sub-pixels in opposite directions.
  • the display controller determines a target reflectance value for the sub-pixel being analyzed. This may involve analyzing video or graphical data describing an image that should be depicted on the display.
  • the target reflectance value may also be dependent upon a quantization error that may arise for the dithering of reflectance values of previously-analyzed sub-pixels. If, for example, the
  • the display controller may reduce the target reflectance value by a corresponding amount to offset that error by subtracting the quantization error from the target reflectance value.
  • the target reflectance value is analyzed to determine whether the target reflectance value falls between the reflectance values R c i OS ejow and R c i 0S e_high- If not, the target reflectance value is compared to a minimum reflectance value of R ⁇ n in step 914. If the target reflectance value is less than a value of Rmin (possibly due to an accumulation of negative reflectance quantization errors), the reflectance value of the sub-pixel is set to a minimum value R m in (in some cases Rciosejow), the sub-pixel's state is set to closed, and the quantization error for the sub-pixel can be calculated in step 916. The quantization error can be calculated by determining the difference between the target reflectance value for the sub-pixel and the reflectance value to which the sub-pixel was actually set (i.e., Rmin).
  • step 918 the target reflectance value is analyzed to determine whether the target reflectance value is greater than a maximum value of R max in step 918. If the target reflectance value is greater than a value of R ma x (possibly due to an
  • the reflectance value of the sub-pixel is set to a maximum value R ma x, and the quantization error for the sub-pixel can be calculated in step 920.
  • the quantization error can be calculated by determining the difference between the target reflectance value for the sub-pixel and the reflectance value to which the sub-pixel was actually set (i.e., R ma x).
  • the sub-pixel can be set to the target reflectance value, which results in a predictable reflectance for the sub-pixel. Accordingly, in step 906, the reflectance value of the sub-pixel is set to the target reflectance value. Additionally, in various embodiments, at this time the quantization error can be set to zero because, as described above, the target reflectance value was configured to offset the input quantization error.
  • step 908 the display controller determines whether the target reflectance value falls closer to Rciosejow or Rciosejiigh- If closer to Rciosejow (i.e., the target reflectance value is less than Rciosejow + (Rciosejiigh - Rciosejow)/2), the sub-pixel's reflectance value is set to Rciosejow (a reflectance value that can be reliably achieved) in step 910.
  • the quantization error for this sub-pixel can also be set.
  • the quantization error will be determined by the difference between the target reflectance value and the reflectance value at which the sub-pixel was ultimately set (i.e., Rciosejow)- Additionally, at this time the sub-pixel has been forced into a closed state.
  • the display controller can designate the sub-pixel as being in a closed state in a memory storing sub-pixel open/closed status data.
  • step 908 the display controller determines that the target reflectance value falls closer to Rciosejiigh (i.e., the target reflectance value is greater than Rciosejow + (Rciosejiigh - Rciosejow)/2), the sub-pixel's reflectance value is set to Rciosejiigh (a reflectance level that can be reliably achieved) in step 912.
  • the quantization error for this sub-pixel can also be set.
  • the quantization error will be determined by the difference between the target reflectance value and the reflectance value at which the sub-pixel was ultimately set (i.e.,
  • the display controller can then move on to the next open sub-pixel in the display and re-execute method 900 of FIG. 9.
  • the quantization error calculated for the present sub-pixel in either of steps 906, 910, 912, 916, or 920 will then be used as an input in calculating the target reflectance value for the next sub-pixel.
  • the reflectance value for individual sub-pixels can be set to values that result in predictable actual reflectance of the sub-pixels.
  • an individual sub-pixel's reflectance value may include some offset or error due to the quantization of reflectance values, the reflectance values of nearby sub-pixels are adjusted to compensate.
  • the local average reflectance values in the display are managed to match those of a source image or data that is being depicted on the display.
  • FIG. 10 depicts a number of sub-pixels within a display.
  • the blank sub-pixels 1002 represent sub-pixels with target reflectance values that can be predictably achieved. As such, the reflectance values of sub-pixels 1002 are not dithered.
  • the hashed sub-pixels 1004 represent sub-pixels with target reflectance values that cannot be predictably achieved (i.e., falling between Rci OS ejow and
  • the reflectance values of sub-pixels 1004 are dithered to either Rciosejow or Rciosejugh (indicated by the different hash directions in FIG. 10). Taken together, the average reflectance value for the group of dithered sub-pixels 1004 will be equal to (or at least approximate) the average target reflectance value for that group of sub-pixels due the dithering algorithm discussed above.
  • the display's controller may evaluate a number of criteria.
  • the first criterion may be that the sub-pixel being evaluated is currently being driven with a structural positive error, where the error exceeds a threshold. That is, the sub- pixel is being driven at a voltage resulting in the sub-pixel having a reflectance value that is greater than the target reflectance value for the sub-pixel. That may result, for example, from accumulated errors in other sub-pixels resulting from the dithering process described above.
  • a second criterion may be whether the local average reflectance value around the sub-pixel being evaluated has a structure positive error, resulting in the local average reflectance value being greater than the target reflectance value. This error may also be compared against a threshold. Another criterion may be that the distribution of closed sub-pixels within the display should achieve a certain spatial uniformity, for a locally spatial uniform source image.
  • Another criterion may require that sub-pixels and signals representing darker image content should not contain temporal noise as this could trigger the undesirable closing of sub-pixels.
  • the display controller may be configured to evaluate each one of these criterion. If all criteria (or some subset of the criteria are met), the display controller can then make the determination that the sub-pixel being evaluated can be closed. The reflectance value of the sub-pixel can then be set to Rc sejow, to ensure that the sub- pixel enters a closed state.
  • the display controller may reference past frames of graphic data that were displayed on the screen in order to evaluate the desired state (e.g., open or closed) for sub-pixels in later frames. Additionally, when comparing the status of one sub-pixel to other (e.g., surrounding) sub-pixels, if error- diffusion techniques have been utilized to implement a dithering process, an error diffusion register utilized in that process may store information describing the reflectance values of surrounding sub-pixels.
  • the display controller can update an entry in the memory storing sub-pixel state data to indicate that the sub-pixel has entered a closed state.
  • the reflectance values for closed pixels being driven at reflectance values near their opening regime can also be dithered.
  • the driving regime should avoid reflectance values that correspond to driving voltages between V ope n _ low and V ope n high as those driving voltages result in unknown reflectance.
  • the display controller may implement a dithering approach to achieve average reflectance values over a number of sub-pixels of between Ro pe n low and
  • FIG. 11 depicts the mapping between a particular reflectance value for a sub-pixel and the corresponding driving voltage based upon the sub-pixel's current state.
  • reflectance values depicted on the vertical axis will correspond, generally, to the actual reflectance of a sub-pixel set to that reflectance value.
  • the sub-pixel can be driven to any reflectance value along the curve that exceeds R op en high- Lower reflectance values cannot be reliably achieved. Instead, when the target reflectance value for a sub-pixel is below Ropen high, the sub-pixel will instead be driven to reflectance value that either equals a minimum reflectance value of R c i 0S e jow or a reflectance value of R ope n high or greater. The reflectance values of adjacent sub-pixels can then be adjusted to compensate. As in the case of an open sub-pixel, specific dithering approaches, such as Floyd- Steinberg dithering, may be utilized to implement this reflectance dithering approach.
  • specific dithering approaches such as Floyd- Steinberg dithering
  • error diffusion may be utilized to distribute the reflectance value offset or error resulting from the dithering of reflectance value of a single sub-pixel to other sub-pixels within the display in order to achieve a target average reflectance value.
  • This offset or error can be referred to as quantization error as it results from the quantization of a target reflectance value of a sub-pixel of a value between R c i OS ejow and R ope n high to either Rci 0S e_ low ⁇ Ropen high-
  • FIG. 12 is a flowchart showing an example method 1200 that may be performed by a display controller to implement the disclosed dithering scheme for pixels in a closed state.
  • Method 1200 may be implemented by the display controller in a similar manner to method 900 depicted in FIG. 9.
  • the display controller determines a target reflectance value for the sub-pixel being analyzed. This may involve analyzing video or graphical data describing an image that should be depicted on the display. The target reflectance value may also be dependent upon a quantization error that may arise for the dithering of previously-analyzed sub-pixels.
  • the display controller may reduce the target reflectance value by a corresponding amount to offset that error.
  • step 1204 the target reflectance value is analyzed to determine whether the target reflectance value is greater than or equal to R op en high- If so, in step 1214 the target reflectance value is analyzed to determine whether the target reflectance value is greater than a maximum value of R max . If the target reflectance value is greater than a value of Rmax (possibly due to an accumulation of reflectance quantization errors), in step 1216 the reflectance value of the sub-pixel is set to a maximum value R ma x, the quantization error for the sub-pixel is calculated, and the sub-pixel is set to an open state.
  • the quantization error can be calculated by determining the difference between the target reflectance value for the sub-pixel and the reflectance value to which the sub-pixel was actually set (i.e., R ma x)-
  • the sub-pixel can be reliably driven to the target reflectance value. Accordingly, in step 1206, the reflectance value of the sub-pixel is set to the target reflectance value. Additionally, in various embodiments, at this time the quantization error can be set to zero because, as described above, the target reflectance value was configured to offset the input quantization error. Additionally, because the sub-pixel has reliably been driven to an open state, the display controller can designate the sub-pixel as being in an open state in a memory storing sub-pixel open/closed state data.
  • step 1204 If, however, in step 1204 it was determined that the target reflectance value is not greater than or equal to R ope n high, the sub-pixel's reflectance value will be quantized to either R c i OS ejow or R ope n high- Accordingly, in step 1208 the display controller determines whether the target reflectance value falls closer to R c i OS e_iow or Ropen high- If closer to Rciosejow (i.e., the target reflectance value is less than Rci OS ejow + (Ropen high - R c iosejow)/2), the target reflectance value is set to Rci OS ejow (a reflectance value that can be reliably achieved) in step 1210.
  • the quantization error for this sub-pixel can also be set.
  • the quantization error will be determined by the difference between the target reflectance value and the reflectance value at which the sub-pixel was ultimately set (i.e., Rci OS ejow).
  • step 1208 the display controller determines that the target reflectance value falls closer to R op en high (i.e., the target reflectance value is greater than R c i OS ejow + (R 0 pen_hi g h - R c iosejow)/2), the target reflectance value is set to Ropen high (a reflectance value that can be reliably achieved) in step 1212.
  • the quantization error for this sub-pixel can also be set.
  • the quantization error will be determined by the difference between the target reflectance value and the reflectance value at which the sub-pixel was ultimately set (i.e.,
  • the display controller can designate the sub-pixel as being in an open state in a memory storing sub-pixel open/closed state data.
  • the display controller can then move on to the next closed sub-pixel in the display and re-execute method 1200 of FIG. 12.
  • the quantization error calculated for the present sub-pixel in either of steps 1206, 1210, 1212, or 1216 can then be used as an input in calculating the reflectance value for the next sub-pixel.
  • a display controller may determine a reflectance value for all sub-pixels in a display by executing either of method 900 depicted in FIG. 9 or method 1200 depicted in FIG. 12 depending upon whether the sub-pixel was initially in an open state or a closed state.
  • FIG. 13 is a flowchart illustrating an example method 1300 for a display controller to apply the disclosed dithering techniques to sub-pixels of a display, where the dithering technique depends upon the open or closed status of each sub-pixel.
  • Method 1300 may be implemented for each sub-pixel within a display, with the display controller implementing method 1300 for a first sub-pixel and then moving to a next sub-pixel and re-executing method 1300. In this manner, the display controller may iterate through each sub-pixel in the display, executing method 1300 once for each sub-pixel. When method 1300 has been executed for all sub-pixels in the display, the display controller can repeat the process again for each sub-pixel.
  • method 1300 could be executed for each sub-pixel within a display having the same color so that quantization errors in reflectance values are distributed amongst sub- pixels of the same color.
  • a controller may execute several instances of method 1300 for different color sub-pixels that may be present within the display.
  • the display controller can iterate through the display's sub-pixels in any suitable manner. For example, the display controller may iterate through sub-pixels from left to right, and top to bottom. Alternatively, the display controller may iterate through each row of sub-pixels in opposite directions.
  • step 1302 the display controller determines whether the sub-pixel being analyzed is in an open or closed state.
  • the open or closed state of the sub-pixel can be determined using data retrieved from a registry or memory configured to store open or closed state information for the display's sub- pixels.
  • step 1304 the display controller executes a dithering algorithm for the open state sub-pixel.
  • the display controller may implement method 900 illustrated in FIG. 9.
  • step 1306 the display controller executes a dithering algorithm for the closed state sub-pixel.
  • the display controller may implement method 1200 illustrated in FIG. 12. After either dithering method has been executed, in step 1308 the display controller moves on the next sub-pixel in the display and the method repeats.
  • FIG. 14 illustrates an example electronic device 1400 that may
  • Electronic device 1400 may comprise any type of electronic device having a display.
  • electronic device 1400 may be a mobile electronic device (e.g., an electronic book reader, a tablet computing device, a laptop computer, a smart phone or other multifunction communication device, a portable digital assistant, a wearable computing device, or an automotive display).
  • electronic device 1400 may be a non-mobile electronic device (e.g., a computer display or a television).
  • FIG. 14 illustrates several example components of electronic device 1400, it is to be appreciated that electronic device 1400 may also include other conventional components, such as an operating system, system busses, input/output components, and the like. Further, in other embodiments, such as in the case of a television or computer monitor, electronic device 1400 may only include a subset of the components illustrated.
  • electronic device 1400 includes a display 1402 and a corresponding display controller 1404.
  • the display 1402 may represent a reflective or transmissive display in some instances or, alternatively, a transflective display (partially transmissive and partially reflective).
  • display 1402 comprises an electrowetting display that employs an applied voltage to change the surface tension of a fluid in relation to a surface.
  • an electrowetting display may include the array of sub- pixels 100 illustrated in FIG. 1, though claimed subject matter is not limited in this respect.
  • wetting properties of a surface may be modified so that the surface becomes increasingly hydrophilic.
  • the modification of the surface tension acts as an optical switch by displacing a colored oil film if a voltage is applied to individual pixels of the display.
  • display 1402 may present a color or grayscale image.
  • the sub-pixels may form the basis for a transmissive, reflective, or transmissive/reflective (transrefiective) display. Further, the sub-pixels may be responsive to high switching speeds (e.g., on the order of several
  • electrowetting displays herein may be suitable for applications such as displaying video or other animated content.
  • FIG. 14 illustrates that some examples of electronic device 1400 may include a touch sensor component 1406 and a touch controller 1408.
  • a touch sensor component 1406 resides with, or is stacked on, display 1402 to form a touch-sensitive display.
  • display 1402 may be capable of both accepting user touch input and rendering content in response to or corresponding to the touch input.
  • touch sensor component 1406 may comprise a capacitive touch sensor, a force sensitive resistance (FSR), an interpolating force sensitive resistance (IFSR) sensor, or any other type of touch sensor.
  • touch sensor component 1406 is capable of detecting touches as well as determining an amount of pressure or force of these touches.
  • FIG. 14 further illustrates that electronic device 1400 may include one or more processors 1410 and one or more computer-readable media 1412, as well as a front light component 1414 (which may alternatively be a backlight component in the case of a backlit display) for lighting display 1402, a cover layer component 1416, such as a cover glass or cover sheet, one or more communication interfaces 1418 and one or more power sources 1420.
  • the communication interfaces 1418 may support both wired and wireless connection to various networks, such as cellular networks, radio, WiFi networks, short range networks (e.g., Bluetooth® technology), and infrared (IR) networks, for example.
  • computer- readable media 1412 (and other computer-readable media described throughout) is an example of computer storage media and may include volatile and nonvolatile memory.
  • computer-readable media 1412 may include, without limitation, RAM, ROM, EEPROM, flash memory, and/or other memory technology, and/or any other suitable medium that may be used to store computer-readable instructions, programs, applications, media items, and/or data which may be accessed by electronic device 1400.
  • Computer-readable media 1412 may be used to store any number of functional components that are executable on processor 1410, as well as content items 1422 and applications 1424.
  • computer-readable media 1412 may include an operating system and a storage database to store one or more content items 1422, such as eBooks, audio books, songs, videos, still images, and the like.
  • Computer-readable media 1412 of electronic device 1400 may also store one or more content presentation applications to render content items on electronic device 1400. These content presentation applications may be implemented as various applications 1424 depending upon content items 1422.
  • the content presentation application may be an electronic book reader application for rending textual electronic books, an audio player for playing audio books or songs, or a video player for playing video.
  • electronic device 1400 may couple to a cover (not illustrated in FIG. 14) to protect the display 1402 (and other components in the display stack or display assembly) of electronic device 1400.
  • the cover may include a back flap that covers a back portion of electronic device 1400 and a front flap that covers display 1402 and the other components in the stack.
  • Electronic device 1400 and/or the cover may include a sensor (e.g., a Hall effect sensor) to detect whether the cover is open (i.e., if the front flap is not atop display 1402 and other components).
  • the sensor may send a signal to front light component 1414 if the cover is open and, in response, front light component 1414 may illuminate display 1402. If the cover is closed, meanwhile, front light component 1414 may receive a signal indicating that the cover has closed and, in response, front light component 1414 may turn off.
  • the amount of light emitted by front light component 1414 may vary. For instance, upon a user opening the cover, the light from the front light may gradually increase to its full illumination.
  • electronic device 1400 includes an ambient light sensor (not illustrated in FIG. 14) and the amount of illumination of front light component 1414 may be based at least in part on the amount of ambient light detected by the ambient light sensor.
  • front light component 1414 may be dimmer if the ambient light sensor detects relatively little ambient light, such as in a dark room; may be brighter if the ambient light sensor detects ambient light within a particular range; and may be dimmer or turned off if the ambient light sensor detects a relatively large amount of ambient light, such as direct sunlight.
  • the settings of display 1402 may vary depending on whether front light component 1414 is on or off, or based on the amount of light provided by front light component 1414. For instance, electronic device 1400 may implement a larger default font or a greater contrast when the light is off compared to when the light is on. In some embodiments, electronic device 1400 maintains, if the light is on, a contrast ratio for display 1402 that is within a certain defined percentage of the contrast ratio if the light is off.
  • touch sensor component 1406 may comprise a capacitive touch sensor that resides atop display 1402.
  • touch sensor component 1406 may be formed on or integrated with cover layer component 1416.
  • touch sensor component 1406 may be a separate component in the stack of the display assembly.
  • Front light component 1414 may reside atop or below touch sensor component 1406. In some instances, either touch sensor component 1406 or front light component 1414 is coupled to a top surface of a protective sheet 1426 of display 1402.
  • front light component 1414 may include a lightguide sheet and a light source (not illustrated in FIG. 14).
  • the lightguide sheet may comprise a substrate (e.g., a transparent thermoplastic such as PMMA or other acrylic), a layer of lacquer and multiple grating elements formed in the layer of lacquer that function to propagate light from the light source towards display 1402; thus, illuminating display 1402.
  • a substrate e.g., a transparent thermoplastic such as PMMA or other acrylic
  • grating elements formed in the layer of lacquer that function to propagate light from the light source towards display 1402; thus, illuminating display 1402.
  • Cover layer component 1416 may include a transparent substrate or sheet having an outer layer that functions to reduce at least one of glare or reflection of ambient light incident on electronic device 1400.
  • cover layer component 1416 may comprise a hard-coated polyester and/or polycarbonate film, including a base polyester or a polycarbonate, that results in a chemically bonded UV- cured hard surface coating that is scratch resistant.
  • the film may be manufactured with additives such that the resulting film includes a hardness rating that is greater than a predefined threshold (e.g., at least a hardness rating that is resistant to a 3h pencil).
  • protective sheet 1426 may include a similar UV-cured hard coating on the outer surface.
  • Cover layer component 1416 may couple to another component or to protective sheet 1426 of display 1402.
  • Cover layer component 1416 may, in some instances, also include a UV filter, a UV- absorbing dye, or the like, for protecting components lower in the stack from UV light incident on electronic device 1400.
  • cover layer component 1416 may include a sheet of high-strength glass having an antiglare and/or antireflective coating.
  • Display 1402 includes protective sheet 1426 overlying an image- displaying component 1428.
  • display 1402 may be preassembled to have protective sheet 1426 as an outer surface on the upper or image-viewing side of display 1402. Accordingly, protective sheet 1426 may be integral with and may overlay image-displaying component 1428.
  • Protective sheet 1426 may be optically transparent to enable a user to view, through protective sheet 1426, an image presented on image-displaying component 1428 of display 1402.
  • protective sheet 1426 may be a transparent polymer film in the range of 25 to 200 micrometers in thickness.
  • protective sheet 1426 may be a transparent polyester, such as polyethylene
  • the outer surface of protective sheet 1426 may include a coating, such as the hard coating described above.
  • the hard coating may be applied to the outer surface of protective sheet 1426 before or after assembly of protective sheet 1426 with image- displaying component 1428 of display 1402.
  • the hard coating may include a photoinitiator or other reactive species in its composition, such as for curing the hard coating on protective sheet 1426.
  • protective sheet 1426 may be dyed with a UV-light-absorbing dye, or may be treated with other UV-absorbing treatment.
  • protective sheet 1426 may be treated to have a specified UV cutoff such that UV light below a cutoff or threshold wavelength is at least partially absorbed by protective sheet 1426, thereby protecting image-displaying component 1428 from UV light.
  • one or more of the components discussed above may be coupled to display 1402 using fluid optically-clear adhesive (LOCA).
  • LOCA fluid optically-clear adhesive
  • the lightguide portion of front light component 1414 may be coupled to display 1402 by placing LOCA on the outer or upper surface of protective sheet 1426. If the LOCA reaches the corner(s) and/or at least a portion of the perimeter of protective sheet 1426, UV-curing may be performed on the LOCA at the corners and/or the portion of the perimeter. Thereafter, the remaining LOCA may be UV-cured and front light component 1414 may be coupled to the LOCA.
  • LOCA fluid optically-clear adhesive
  • the techniques By first curing the corner(s) and/or the perimeter, the techniques effectively create a barrier for the remaining LOCA and also prevent the formation of air gaps in the LOCA layer, thereby increasing the efficacy of front light component 1414.
  • the LOCA may be placed near a center of protective sheet 1426, and pressed outwards towards a perimeter of the top surface of protective sheet 1426 by placing front light component 1414 on top of the LOCA.
  • the LOCA may then be cured by directing UV light through front light component 1414.
  • various techniques such as surface treatment of the protective sheet, may be used to prevent discoloration of the LOCA and/or protective sheet 1426.
  • electronic device 1400 may have additional features or functionality.
  • electronic device 1400 may also include additional data storage devices (removable and/or nonremovable) such as, for example, magnetic disks, optical disks, or tape.
  • additional data storage media which may reside in a control board, may include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data.
  • volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data.
  • a method of driving an electrowetting display device including a plurality of sub-pixels includes determining a target reflectance value for a sub-pixel in the plurality of sub-pixels, determining a first reflectance value of the sub-pixel, and comparing the first reflectance value and the target reflectance value to a threshold value.
  • the method includes setting a reflectance value of the sub-pixel to a second reflectance value greater than or equal to the threshold value, and setting the reflectance value of the sub-pixel to the target reflectance value.
  • the method includes setting the reflectance value of the sub-pixel to the target reflectance value without setting the reflectance value of the sub-pixel to the second reflectance value.
  • a method of driving an electrowetting display device including a plurality of sub-pixels includes determining a target reflectance value for a sub-pixel in the plurality of sub-pixels. The method includes setting a reflectance value of the sub-pixel to the target reflectance value by setting the reflectance value of the sub-pixel to a first reflectance value greater than a threshold value, and setting the reflectance value of the sub-pixel to the target reflectance value.
  • a display device includes a sub-pixel including a plurality of sub-pixel walls defining a cavity, and a first fluid and a second fluid within the cavity, the first fluid being immiscible with the second fluid.
  • the display device includes a display controller including an input line for receiving data relating to a target reflectance value of the sub-pixel, and an output line for providing at least one display signal level for applying a voltage to a first electrode in the sub-pixel to provide a driving voltage for the sub-pixel.
  • the display controller is configured to determine a target reflectance value for the sub-pixel, and set a reflectance value of the sub-pixel to the target reflectance value by setting the reflectance value of the sub- pixel to a first reflectance value greater than a threshold value, and setting the reflectance value of the sub-pixel to the target reflectance value.
  • a method of driving an electrowetting display device including a plurality of sub-pixels includes determining whether a sub-pixel in the plurality of sub-pixels is in an open state or a closed state, determining a target reflectance value for the sub-pixel, and, for the sub-pixel in the open state, determining that the target reflectance value is less than a first threshold value, and setting a reflectance value of the sub-pixel to either a minimum reflectance value or the first threshold value.
  • the method includes, for the sub-pixel in the closed state, determining that the target reflectance value is less than a second threshold value, and setting the reflectance of the sub-pixel to either the minimum reflectance value or the second threshold value.
  • a method of driving an electrowetting display device including a plurality of sub-pixels includes determining whether a sub-pixel in the plurality of sub-pixels is in an open state or a closed state, determining a target reflectance value for the sub-pixel, and setting a reflectance value of the sub-pixel based upon whether the sub-pixel is in the open state or the closed state and the target reflectance value.
  • a display device includes a sub-pixel including a plurality of sub-pixel walls defining a cavity, and a first fluid and a second fluid within the cavity, the first fluid being immiscible with the second fluid.
  • the display device includes a display controller including an input line for receiving data relating to a target reflectance of the sub-pixel, and an output line for providing at least one display signal level for applying a voltage to a first electrode in the sub-pixel to establish a driving voltage for the sub-pixel.
  • the display controller is configured to determine whether the sub-pixel is in an open state or a closed state, determine a target reflectance value for the sub-pixel, and set a reflectance value of the sub-pixel based upon whether the sub-pixel is in the open state or the closed state and the target reflectance value.
  • a method of driving an electrowetting display device including a plurality of sub-pixels comprising:
  • determining a target reflectance value for a sub-pixel in the plurality of sub-pixels determining a first reflectance value of the sub-pixel
  • a method of driving an electrowetting display device including a plurality of sub-pixels comprising:
  • a display device comprising:
  • a sub-pixel including:
  • a display controller including:
  • an output line for providing at least one display signal level for applying a voltage to a first electrode in the sub-pixel to provide a driving voltage for the sub-pixel
  • the display controller is configured to:
  • the threshold value is a lowest reflectance value that causes the sub-pixel to be in an open state when the reflectance value of the sub-pixel is set to the threshold value.
  • the controller is configured to set the reflectance value of the sub-pixel to the first reflectance value by setting a voltage of the output line to a driving voltage corresponding to the first reflectance value.
  • controller configured to, before setting the reflectance value of the sub-pixel to the first reflectance value, determine whether the sub-pixel is in an open state or a closed state and only set the reflectance value of the sub-pixel to the first reflectance value when the sub-pixel is in a closed state.
  • a method of driving an electrowetting display device including a plurality of sub-pixels comprising: determining whether a sub-pixel in the plurality of sub-pixels is in an open state or a closed state;
  • a method of driving an electrowetting display device including a plurality of sub-pixels comprising:
  • determining whether a sub-pixel in the plurality of sub-pixels is in an open state or a closed state determining whether a sub-pixel in the plurality of sub-pixels is in an open state or a closed state; determining a target reflectance value for the sub-pixel; and setting a reflectance value of the sub-pixel based upon whether the sub-pixel is in the open state or the closed state and the target reflectance value.
  • setting the reflectance value of the sub-pixel to either the minimum reflectance value or the first threshold value includes: comparing the target reflectance value to the minimum reflectance value and the first threshold value;
  • a display device comprising:
  • a sub-pixel including:
  • a display controller including:
  • an output line for providing at least one display signal level for applying a voltage to a first electrode in the sub-pixel to establish a driving voltage for the sub- pixel
  • the display controller is configured to:

Abstract

L'invention concerne un système et un procédé d'attaque d'un dispositif d'affichage à électromouillage, comprenant une pluralité de sous-pixels. Une valeur de réflectance cible pour un sous-pixel parmi la pluralité de sous-pixels est déterminée. Une valeur de réflectance du sous-pixel est réglée sur la valeur de réflectance cible par réglage de la valeur de réflectance du sous-pixel sur une première valeur de réflectance supérieure à une valeur seuil et réglage de la valeur de réflectance du sous-pixel sur la valeur de réflectance cible.
PCT/US2016/039612 2015-06-29 2016-06-27 Système et procédé d'attaque de dispositif d'affichage à électromouillage WO2017003939A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US14/754,532 2015-06-29
US14/754,532 US9728143B2 (en) 2015-06-29 2015-06-29 System and method for driving electrowetting display device
US14/754,501 US9865200B2 (en) 2015-06-29 2015-06-29 System and method for driving electrowetting display device
US14/754,501 2015-06-29

Publications (1)

Publication Number Publication Date
WO2017003939A1 true WO2017003939A1 (fr) 2017-01-05

Family

ID=56409206

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2016/039612 WO2017003939A1 (fr) 2015-06-29 2016-06-27 Système et procédé d'attaque de dispositif d'affichage à électromouillage

Country Status (1)

Country Link
WO (1) WO2017003939A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019034229A1 (fr) * 2017-08-14 2019-02-21 Optos Plc Commande d'élément optique
CN109817167A (zh) * 2019-02-26 2019-05-28 江西兴泰科技有限公司 一种消除三色电子纸模组显示中残留异色粒子的驱动波形调试方法
CN113790818A (zh) * 2021-08-10 2021-12-14 中国电子科技集团公司第十三研究所 可见光热反射测温方法及测温设备

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120256898A1 (en) * 2009-10-29 2012-10-11 Samsung Lcd Netherlands R & D Center B.V. Driving an electrowetting display device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120256898A1 (en) * 2009-10-29 2012-10-11 Samsung Lcd Netherlands R & D Center B.V. Driving an electrowetting display device

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
VAN DIJK R ET AL: "68.3: Gray Scales for Video Applications on Electrowetting Displays", SID 2006, 2006 SID INTERNATIONAL SYMPOSIUM, SOCIETY FOR INFORMATION DISPLAY, vol. XXXVII, 24 May 2005 (2005-05-24), pages 1926 - 1929, XP007012875, ISSN: 0006-966X *
YUNG-HSIANG CHIU ET AL: "Accurate-gray-level and quick-response driving methods for high-performance electrowetting displays", JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY - SID, vol. 19, no. 11, November 2011 (2011-11-01), US, pages 741, XP055307990, ISSN: 1071-0922, DOI: 10.1889/JSID19.11.741 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019034229A1 (fr) * 2017-08-14 2019-02-21 Optos Plc Commande d'élément optique
US20200166676A1 (en) * 2017-08-14 2020-05-28 Optos Plc Optical Element Control
US11635552B2 (en) 2017-08-14 2023-04-25 Optos Plc Optical element control
CN109817167A (zh) * 2019-02-26 2019-05-28 江西兴泰科技有限公司 一种消除三色电子纸模组显示中残留异色粒子的驱动波形调试方法
CN113790818A (zh) * 2021-08-10 2021-12-14 中国电子科技集团公司第十三研究所 可见光热反射测温方法及测温设备
CN113790818B (zh) * 2021-08-10 2023-09-26 中国电子科技集团公司第十三研究所 可见光热反射测温方法及测温设备

Similar Documents

Publication Publication Date Title
US10311805B2 (en) System and method for driving electrowetting display device
US10241319B2 (en) Electrowetting display pixels with fluid motion initiator
US10394014B2 (en) Integrated black matrix including color filter materials
US9953589B2 (en) Reset drive voltage to enhance grey scale resolution for an electrowetting display device
US10120184B1 (en) Reflectance in electrowetting displays
US20180174527A1 (en) Control system for an electrowetting display device
US9459445B1 (en) Dual gate pixel reset for a display device
US9684161B1 (en) Reflectance in electrowetting displays
US10269311B2 (en) Control system for an electrowetting display device with memory controller
US10186212B2 (en) Dynamic reset voltage for an electrowetting display device
US20180174528A1 (en) Control system for an electrowetting display device with rendering engine
WO2017003939A1 (fr) Système et procédé d'attaque de dispositif d'affichage à électromouillage
US10255835B2 (en) Luminance and reducing power consumption in electrowetting displays
EP3161542B1 (fr) Procédés et appareils de fabrication d'écrans à électromouillage
US9804382B1 (en) Electrowetting display pixels with pixel walls having non-planar side surfaces
US9772488B2 (en) Electrowetting display pixels with patterned electric field
US9865200B2 (en) System and method for driving electrowetting display device
US10297211B1 (en) Photo sensitive control for an electrowetting display device
US10379340B1 (en) Electrowetting pixel with main and initiation electrodes and connected storage capacitors
US10156714B1 (en) Electrowetting pixel with bottom electrode to reduce electromagnetic fringe fields
US10401614B1 (en) System and method for electrowetting display device with color filters having variable optical density
US10379339B1 (en) Electrowetting display device configuration for reflective and transmissive modes
US10490141B1 (en) Reset pulse control to manage flicker of an electrowetting display device
US9625703B1 (en) Pixel wall configuration for an electrowetting display
US10345575B1 (en) Global reset for an electrowetting display device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16738312

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16738312

Country of ref document: EP

Kind code of ref document: A1