Patent Grant
9898974
This disclosure relates to electromechanical systems and devices. More specifically, this disclosure relates to a display drive scheme without a reset.
Electromechanical systems (EMS) include devices having electrical and mechanical elements, actuators, transducers, sensors, optical components such as mirrors and optical films, and electronics. EMS devices or elements can be manufactured at a variety of scales including, but not limited to, microscales and nanoscales. For example, microelectromechanical systems (MEMS) devices can include structures having sizes ranging from about a micron to hundreds of microns or more. Nanoelectromechanical systems (NEMS) devices can include structures having sizes smaller than a micron including, for example, sizes smaller than several hundred nanometers. Electromechanical elements may be created using deposition, etching, lithography, and/or other micromachining processes that etch away parts of substrates and/or deposited material layers, or that add layers to form electrical and electromechanical devices.
One type of EMS device is called an interferometric modulator (IMOD). The term IMOD or interferometric light modulator refers to a device that selectively absorbs and/or reflects light using the principles of optical interference. In some implementations, an IMOD display element may include a pair of conductive plates, one or both of which may be transparent and/or reflective, wholly or in part, and capable of relative motion upon application of an appropriate electrical signal. For example, one plate may include a stationary layer deposited over, on or supported by a substrate and the other plate may include a reflective membrane separated from the stationary layer by an air gap. The position of one plate in relation to another can change the optical interference of light incident on the IMOD display element. IMOD-based display devices have a wide range of applications, and are anticipated to be used in improving existing products and creating new products, especially those with display capabilities.
One plate, or movable element of the IMOD display element, can move from an initial position associated with a first color to a second, new position such that the IMOD display element provides a second, new color. Transitioning directly from the initial position to the second position may introduce errors such that the position of the plate is at a slightly incorrect position rather than the expected second position. More errors may be introduced and accumulated when the position of the plate is to move from the second position to a third position. Accordingly, rather than transitioning directly from the initial position to the second position, an intermediate reset position may first be transitioned to in order to reduce the accumulation of errors, followed by transitioning from the intermediate reset position to the second position. Afterwards, the plate may be positioned back to the reset position and then repositioned to the third position. As such, using the intermediate reset position may reduce accumulated errors.
However, moving the plate to the reset position before moving to the new position may introduce visual artifacts, decrease color saturation, and require extra circuitry to provide the reset functionality.
The systems, methods and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.
One innovative aspect of the subject matter described in this disclosure can be implemented in a circuit including a controller capable of determining a first voltage to apply to an electrode of a display unit of an array of display units to position a movable element of the display unit from a first position towards a second position, and the controller further capable of determining a second voltage to apply to the electrode of the display unit to position the movable element of the display unit at the second position.
In some implementations, the first voltage can correspond with a transition in color of the display unit, the first position corresponding with a first color, and the second position corresponding with a second color.
In some implementations, positioning the movable element of the display unit from the first position towards the second position can include moving the movable element into a range including the second position.
In some implementations, the second voltage can correspond with a voltage to position the movable element from a position in the range to the second position.
In some implementations, the controller can further be capable of determining a third voltage to apply to the electrode of the display unit to release the movable element of the display unit from hysteresis.
In some implementations, releasing the movable element of the display unit from hysteresis can include positioning the movable element to a position outside of a hysteresis region.
In some implementations, the circuit can include a frame buffer including data indicating a current color corresponding to the first position of the movable element of the display unit; and a storage device to store lookup tables (LUTs) indicating the first voltage and the second voltage.
In some implementations, the controller can determine the first voltage and the second voltage based on the data indicating the current color corresponding to the first position of the movable element, and image data indicating an intended color corresponding to the second position of the movable element.
In some implementations, the circuit can include a display including the array of display units; a processor that is capable of communicating with the display device, the processor being configured to process image data; and a memory device that is capable of communicating with the processor.
In some implementations, the circuit can include a driver circuit capable of sending at least one signal to the display; and wherein the controller is capable of sending at least a portion of the image data to the driver circuit.
In some implementations, the circuit can include an image source module capable of sending the image data to the processor, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.
In some implementations, the circuit can include an input device capable of receiving input data and to communicate the input data to the processor.
Another innovative aspect of the subject matter described in this disclosure can be implemented in a system including a voltage data source indicating a first voltage corresponding with transitioning a display unit from providing a first color to a second color, and indicating a second voltage corresponding to the second color; and a driver circuit capable of providing the first voltage to an electrode of the display unit to position a movable element of the display unit from a first position associated with the first color towards a second position associated with the second color, and the driver circuit further capable of providing the second voltage to the electrode of the display unit to position the movable element of the display unit to the second position.
In some implementations, the driver circuit can be further capable of providing the first voltage to move the movable element into a range including the second position.
In some implementations, the second voltage can correspond with a voltage to position the movable element from a position in the range to the second position.
Another innovative aspect of the subject matter described in this disclosure can be implemented in a method including providing, by a driver circuit, a first voltage to an electrode of a display unit to position a movable element of the display unit from a first position towards a second position; and providing, by the driver circuit, a second voltage to the electrode of the display unit to position the movable element of the display unit to the second position.
In some implementations, the method can include providing, by the driver circuit, a third voltage to the electrode of the display unit to release the movable element of the display unit from hysteresis.
In some implementations, releasing the movable element of the display unit from hysteresis can include positioning the movable element to a position outside of a hysteresis region.
In some implementations, the first voltage can correspond with a transition in color of the display unit, the first position corresponding with a first color, and the second position corresponding with a second color.
In some implementations, positioning the movable element of the display unit from the first position towards the second position can include positioning the movable element in a range including the second position.
Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Although the examples provided in this disclosure are primarily described in terms of EMS and MEMS-based displays the concepts provided herein may apply to other types of displays such as liquid crystal displays, organic light-emitting diode (“OLED”) displays, and field emission displays. Other features, aspects, and advantages will become apparent from the description, the drawings and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.
Like reference numbers and designations in the various drawings indicate like elements.
The following description is directed to certain implementations for the purposes of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations may be implemented in any device, apparatus, or system that can be configured to display an image, whether in motion (such as video) or stationary (such as still images), and whether textual, graphical or pictorial. More particularly, it is contemplated that the described implementations may be included in or associated with a variety of electronic devices such as, but not limited to: mobile telephones, multimedia Internet enabled cellular telephones, mobile television receivers, wireless devices, smartphones, Bluetooth® devices, personal data assistants (PDAs), wireless electronic mail receivers, hand-held or portable computers, netbooks, notebooks, smartbooks, tablets, printers, copiers, scanners, facsimile devices, global positioning system (GPS) receivers/navigators, cameras, digital media players (such as MP3 players), camcorders, game consoles, wrist watches, clocks, calculators, television monitors, flat panel displays, electronic reading devices (e.g., e-readers), computer monitors, auto displays (including odometer and speedometer displays, etc.), cockpit controls and/or displays, camera view displays (such as the display of a rear view camera in a vehicle), electronic photographs, electronic billboards or signs, projectors, architectural structures, microwaves, refrigerators, stereo systems, cassette recorders or players, DVD players, CD players, VCRs, radios, portable memory chips, washers, dryers, washer/dryers, parking meters, packaging (such as in electromechanical systems (EMS) applications including microelectromechanical systems (MEMS) applications, as well as non-EMS applications), aesthetic structures (such as display of images on a piece of jewelry or clothing) and a variety of EMS devices. The teachings herein also can be used in non-display applications such as, but not limited to, electronic switching devices, radio frequency filters, sensors, accelerometers, gyroscopes, motion-sensing devices, magnetometers, inertial components for consumer electronics, parts of consumer electronics products, varactors, liquid crystal devices, electrophoretic devices, drive schemes, manufacturing processes and electronic test equipment. Thus, the teachings are not intended to be limited to the implementations depicted solely in the Figures, but instead have wide applicability as will be readily apparent to one having ordinary skill in the art.
An interferometric modulator (IMOD) can include a movable element, such as a mirror, that may be positioned at various points (or locations) in order to reflect light at a specific wavelength at each specific point. For example, the movable element can be moved from an initial position associated with a first color (e.g., red) to a second position associated with a second color (e.g., blue).
In some implementations, the IMOD has three (3) terminals. The movable element may be positioned by applying voltages to the three terminals of the IMOD. However, moving directly from the initial position to the second position can be imprecise due to process variations, defects, noise, calibration issues, and/or other conditions affecting the voltages received by the terminals of the IMOD. For example, if the movable element should transition from a position corresponding to red to a position corresponding to blue, then 5 V may need to be applied to an electrode. However, the electrode may receive 4.98 V instead (due to the aforementioned conditions), and therefore, the movable element may be positioned at a slightly incorrect position rather than the expected position. As another example, while 5 V may be the usual, or expected, voltage normally applied for the transition, some electrodes associated with other movable elements may need a slightly different voltage, for example 4.98 V due to process variations (among movable elements) or errors from calibration. This may be problematic because the system may provide voltages to the electrodes of the IMOD based on the expected position of the mirror (i.e., the expected second position rather than the slightly incorrect position). If the movable element is at the incorrect position and the mirror is to move to a third position, the voltage applied to the electrode would be based on the movable element being at the second position rather than the incorrect position, and therefore, the movable element may be positioned to another incorrect position. These positioning errors may accumulate such that eventually the movable element's actual position drifts further and further away from the expected position.
A mechanical reset may be used to position the movable element to a reset position before moving to the second position. The reset position may be an intermediate position between moving the movable element from a first position to a second position. Since the movable element would always be moved to the reset position before moving to the second position, an accumulation of positioning errors can be avoided. However, a mechanical reset may need extra circuitry, decrease color saturation, and may generate visual artifacts.
Some implementations of the subject matter described herein provide for the positioning of the movable element without the mechanical reset. The movable element may move from a first position associated with a first color towards a second position associated with a second color and within a range of the second position by applying a voltage associated with a transition from the first color to the second color. Afterwards, a second voltage may be applied to stabilize the movable element within the range to the specific second position.
Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. Positioning the movable elements without moving to a reset position may allow for increased color saturation. Additionally, visual artifacts from moving to the reset position may be avoided. Moreover, dedicated reset circuitry may also be eliminated.
An example of a suitable EMS or MEMS device or apparatus, to which the described implementations may apply, is a reflective display device. Reflective display devices can incorporate interferometric modulator (IMOD) display elements that can be implemented to selectively absorb and/or reflect light incident thereon using principles of optical interference. IMOD display elements can include a partial optical absorber, a reflector that is movable with respect to the absorber, and an optical resonant cavity defined between the absorber and the reflector. In some implementations, the reflector can be moved to two or more different positions, which can change the size of the optical resonant cavity and thereby affect the reflectance of the IMOD. The reflectance spectra of IMOD display elements can create fairly broad spectral bands that can be shifted across the visible wavelengths to generate different colors. The position of the spectral band can be adjusted by changing the thickness of the optical resonant cavity. One way of changing the optical resonant cavity is by changing the position of the reflector with respect to the absorber.
The IMOD display device can include an array of IMOD display elements which may be arranged in rows and columns. Each display element in the array can include at least a pair of reflective and semi-reflective layers, such as a movable reflective layer (i.e., a movable layer, also referred to as a mechanical layer) and a fixed partially reflective layer (i.e., a stationary layer), positioned at a variable and controllable distance from each other to form an air gap (also referred to as an optical gap, cavity or optical resonant cavity). The movable reflective layer may be moved between at least two positions. For example, in a first position, i.e., a relaxed position, the movable reflective layer can be positioned at a distance from the fixed partially reflective layer. In a second position, i.e., an actuated position, the movable reflective layer can be positioned more closely to the partially reflective layer. Incident light that reflects from the two layers can interfere constructively and/or destructively depending on the position of the movable reflective layer and the wavelength(s) of the incident light, producing either an overall reflective or non-reflective state for each display element. In some implementations, the display element may be in a reflective state when unactuated, reflecting light within the visible spectrum, and may be in a dark state when actuated, absorbing and/or destructively interfering light within the visible range. In some other implementations, however, an IMOD display element may be in a dark state when unactuated, and in a reflective state when actuated. In some implementations, the introduction of an applied voltage can drive the display elements to change states. In some other implementations, an applied charge can drive the display elements to change states.
The depicted portion of the array in
In
The optical stack 16 can include a single layer or several layers. The layer(s) can include one or more of an electrode layer, a partially reflective and partially transmissive layer, and a transparent dielectric layer. In some implementations, the optical stack 16 is electrically conductive, partially transparent and partially reflective, and may be fabricated, for example, by depositing one or more of the above layers onto a transparent substrate 20. The electrode layer can be formed from a variety of materials, such as various metals, for example indium tin oxide (ITO). The partially reflective layer can be formed from a variety of materials that are partially reflective, such as various metals (e.g., chromium and/or molybdenum), semiconductors, and dielectrics. The partially reflective layer can be formed of one or more layers of materials, and each of the layers can be formed of a single material or a combination of materials. In some implementations, certain portions of the optical stack 16 can include a single semi-transparent thickness of metal or semiconductor which serves as both a partial optical absorber and electrical conductor, while different, electrically more conductive layers or portions (e.g., of the optical stack 16 or of other structures of the display element) can serve to bus signals between IMOD display elements. The optical stack 16 also can include one or more insulating or dielectric layers covering one or more conductive layers or an electrically conductive/partially absorptive layer.
In some implementations, at least some of the layer(s) of the optical stack 16 can be patterned into parallel strips, and may form row electrodes in a display device as described further below. As will be understood by one having ordinary skill in the art, the term “patterned” is used herein to refer to masking as well as etching processes. In some implementations, a highly conductive and reflective material, such as aluminum (Al), may be used for the movable reflective layer 14, and these strips may form column electrodes in a display device. The movable reflective layer 14 may be formed as a series of parallel strips of a deposited metal layer or layers (orthogonal to the row electrodes of the optical stack 16) to form columns deposited on top of supports, such as the illustrated posts 18, and an intervening sacrificial material located between the posts 18. When the sacrificial material is etched away, a defined gap 19, or optical cavity, can be formed between the movable reflective layer 14 and the optical stack 16. In some implementations, the spacing between posts 18 may be approximately 1-1000 μm, while the gap 19 may be approximately less than 10,000 Angstroms (Å).
In some implementations, each IMOD display element, whether in the actuated or relaxed state, can be considered as a capacitor formed by the fixed and moving reflective layers. When no voltage is applied, the movable reflective layer 14 remains in a mechanically relaxed state, as illustrated by the display element 12 on the left in
The processor 21 can be configured to communicate with an array driver 22. The array driver 22 can include a row driver circuit 24 and a column driver circuit 26 that provide signals to, for example a display array or panel 30. The cross section of the IMOD display device illustrated in
In some implementations, the packaging of an EMS component or device, such as an IMOD-based display, can include a backplate (alternatively referred to as a backplane, back glass or recessed glass) which can be configured to protect the EMS components from damage (such as from mechanical interference or potentially damaging substances). The backplate also can provide structural support for a wide range of components, including but not limited to driver circuitry, processors, memory, interconnect arrays, vapor barriers, product housing, and the like. In some implementations, the use of a backplate can facilitate integration of components and thereby reduce the volume, weight, and/or manufacturing costs of a portable electronic device.
The backplate 92 can be essentially planar or can have at least one contoured surface (e.g., the backplate 92 can be formed with recesses and/or protrusions). The backplate 92 may be made of any suitable material, whether transparent or opaque, conductive or insulating. Suitable materials for the backplate 92 include, but are not limited to, glass, plastic, ceramics, polymers, laminates, metals, metal foils, Kovar and plated Kovar.
As shown in
The backplate components 94a and/or 94b can include one or more active or passive electrical components, such as transistors, capacitors, inductors, resistors, diodes, switches, and/or integrated circuits (ICs) such as a packaged, standard or discrete IC. Other examples of backplate components that can be used in various implementations include antennas, batteries, and sensors such as electrical, touch, optical, or chemical sensors, or thin-film deposited devices.
In some implementations, the backplate components 94a and/or 94b can be in electrical communication with portions of the EMS array 36. Conductive structures such as traces, bumps, posts, or vias may be formed on one or both of the backplate 92 or the substrate 20 and may contact one another or other conductive components to form electrical connections between the EMS array 36 and the backplate components 94a and/or 94b. For example,
The backplate components 94a and 94b can include one or more desiccants which act to absorb any moisture that may enter the EMS package 91. In some implementations, a desiccant (or other moisture absorbing materials, such as a getter) may be provided separately from any other backplate components, for example as a sheet that is mounted to the backplate 92 (or in a recess formed therein) with adhesive. Alternatively, the desiccant may be integrated into the backplate 92. In some other implementations, the desiccant may be applied directly or indirectly over other backplate components, for example by spray-coating, screen printing, or any other suitable method.
In some implementations, the EMS array 36 and/or the backplate 92 can include mechanical standoffs 97 to maintain a distance between the backplate components and the display elements and thereby prevent mechanical interference between those components. In the implementation illustrated in
Although not illustrated in
In alternate implementations, a seal ring may include an extension of either one or both of the backplate 92 or the substrate 20. For example, the seal ring may include a mechanical extension (not shown) of the backplate 92. In some implementations, the seal ring may include a separate member, such as an O-ring or other annular member.
In some implementations, the EMS array 36 and the backplate 92 are separately formed before being attached or coupled together. For example, the edge of the substrate 20 can be attached and sealed to the edge of the backplate 92 as discussed above. Alternatively, the EMS array 36 and the backplate 92 can be formed and joined together as the EMS package 91. In some other implementations, the EMS package 91 can be fabricated in any other suitable manner, such as by forming components of the backplate 92 over the EMS array 36 by deposition.
The implementation of display module 710 in display array 30 may include a variety of different designs. As an example, display module 710 in the fourth row may include switch 720 and display unit 750. Display module 710 may be provided a row signal, reset signal, bias signal, and a common signal from row driver circuit 24. Display module 710 may also be provided a data, or column, signal from column driver circuit 26. In some implementations, display unit 750 may be coupled with switch 720, such as a transistor with its gate coupled to the row signal and its drain coupled with the column signal. Each display unit 750 may include an IMOD display element as a pixel.
Some IMODs are three-terminal devices that use a variety of signals.
Display unit 750 may be a three-terminal IMOD including three terminals or electrodes: Vbias electrode 855, Vd electrode 860, and Vcom electrode 865. Display unit 750 may also include movable element 870 and dielectric 875. Movable element 870 may include a mirror, as previously discussed. Movable element 870 may be coupled with Vd electrode 860. Additionally, air gap 890 may be between Vbias electrode 855 and Vd electrode 860. Air gap 885 may be between Vd electrode 860 and Vcom electrode 865. In some implementations, display unit 750 may also include one or more capacitors. For example, one or more capacitors can be coupled between Vd electrode 860 and Vcom electrode 865 and/or between Vbias electrode 855 and Vd electrode 860. Other configurations of display unit 750 may include dielectric 875 or another dielectric being close to Vcom electrode 865.
Movable element 870 may be positioned at various points between Vbias electrode 855 and Vcom electrode 865 to reflect light at a specific wavelength, and therefore, provide color. In particular, voltages applied to Vbias electrode 855, Vd electrode 860, and Vcom electrode 865 may determine the position of movable element 870. Voltages for Vreset 895, Vcolumn 820, Vrow 830, Vcom electrode 865, and Vbias electrode 855 may be provided by driver circuits such as row driver circuit 24 and column driver circuit 26. In some implementations, Vcom electrode 865 may be coupled to ground rather than driven by row driver circuit 24 or column driver circuit 26. Accordingly, movable element 870 may be positioned between Vbias electrode 855 and Vcom electrode 865 and the sizes of air gaps 885 and 890 may change based on the position of movable element 870.
In some implementations, positioning movable element 870 may result in an accumulation of positioning errors that cause the actual position of movable element 870 to deviate from the expected position. For example, movable element 870 may be at a first position such that display unit 750 provides the color red. Display unit 750 may next need to provide the color blue. Therefore, the position of movable element 870 may need to change to a new, second position to provide the color blue. Accordingly, voltages may be applied to Vcom electrode 865, Vd electrode 860, and Vbias electrode 855 such that movable element 870 may be positioned to the new, second position from the first position associated with the color red. Movable element 870 may then be positioned from the second position to a third position to provide another color.
However, positioning movable element 870 directly from the first position to the second position may result in a positioning error. In particular, due to process variations, defects, noise, calibration errors, and other conditions, the voltages applied to an electrode may deviate from the expected voltage. As an example, Vd electrode 860 may need to be biased at 5 V to position movable element 870 to the second position to provide the color blue. However, Vd electrode 860 may in fact be biased at 4.98 V, slightly off from the expected 5 V. As a result, movable element 870 may be positioned at an incorrect position providing a slightly different color than the expected color. When movable element 870 is positioned to the third position, the voltages applied to the electrodes are based on movable element 870 being at the expected position, and therefore, movable element 870 may be positioned to another incorrect position. As movable element 870 is repeatedly positioned, the positioning errors may accumulate such that the actual position of movable element 870 has drifted away from its expected position.
In
A reset scheme to position movable element 870 to an intermediate reset position between positions may be used to reduce the accumulation of positioning errors.
In
The reset scheme portrayed in
In some implementations, even if movable element 870 should stay at the same position to provide the same color (e.g., between different frames), it may still be positioned to the reset position and then repositioned back to the same position. The polarity of the electric fields of display unit 750 may be switched to reduce charge accumulation, and therefore, movable element 870 associated with a color or position in a first frame may be moved to the reset position, and then moved back to the same position in a second frame to provide the same color, but the voltages on the electrodes of display unit 750 may be changed. The polarities may also be switched when movable element 870 moves to new positions.
However, positioning movable element 870 to the reset position may introduce visual artifacts, decrease color saturation, and require extra circuitry to provide the reset functionality. For example, if display or array 30 is operating at a lower frequency (e.g., a 1 Hz refresh rate), then a “ripping” process involving biasing each row of display modules 710 one-after-another such that each row of display units 750 is positioned to the proper positions may be visible due to the reset positioning.
In more detail, the positions that movable element 870 may be positioned to may be among ranges 1105a-h in
Different voltages may be applied to the electrodes of display unit 750 in order to move movable element 870 to different positions, as previously discussed. For example, if movable element 870 of display unit 750 is at the middle of range 1105a reflecting the color red, and it is intended to be repositioned to the middle of range 1105d to reflect the color green, then 4.5 V may be applied to Vd electrode 860. However, other voltages may be applied if movable element 870 should be positioned to another color other than green (e.g., positioning from red to blue in the middle of range 1105g may need 5 V applied to Vd electrode 860). Accordingly, each transition from one position associated with one color to another position associated with another color may be performed by applying a specific voltage to an electrode. For example, Vcom electrode 865 may be at 0 V, Vbias electrode may switch between 12 V and −12V depending upon a polarity as discussed later herein, and Vd electrode 860 may be applied the voltage corresponding to the transition between the positions and colors.
In
As another example, while 4.5 V may be the usual, or expected, voltage normally applied for the transition from position 1110 corresponding to red to position 1115 corresponding to green, some electrodes associated with other movable elements 870 may need a slightly different voltage, for example 4.4 V due to process variations or errors from calibration. If 4.5 V is applied to Vd electrode 860, then movable element 870 may also be positioned to position 1120 rather than position 1115. As a result, a similar process as in
If the first application of a voltage to Vd electrode 860 positions movable element 870 at the correct, intended position 1115 (i.e., no positioning errors occurred), then the second application of a voltage to Vd electrode 860 would maintain the position of movable element 870.
Each of ranges 1105a-1105h may be associated with a voltage range or a number of voltages. If movable element 870 is within the range, the application of a particular voltage may allow for the movable element 870 to stabilize to a particular position within the range (e.g., the middle of the range). For example, if movable element 870 is within range 1105a, then an application of 2 V may position it to the middle. An application of 2.2 V may position it to a non-middle position. Likewise, if movable element 870 is within range 1105f, then 2 V may position it to the middle of range 1105f. If movable element 870 is within range 1105b, then 2.4 V may position it to the middle of range 1105b.
Accordingly, if the current position of movable element 870 is known, the next, intended position may be provided by determining the proper application of voltages to position movable element between positions (e.g., a transition between the current position to an intended position), providing the voltage for positioning or driving movable element 870 towards the intended position and within a range of the intended position (e.g., as in
In some implementations, variations to the two-part technique may be performed. For example, positioning movable element 870 from some positions and colors to some other positions and colors may involve a three-part technique. In particular, some positions and colors may not be able to directly transition to another position and color due to hysteresis. For example, an IMOD display element may use, in one implementation, about a 5 volt potential difference to cause the movable reflective layer, or movable element 870 including a mirror, to change from a 4 volt state (or position) to a 5 volt state (or position). However, the movable reflective layer may stay at the 5 volt state as the potential difference drops back below, in this example, 5 volts, because the movable reflective layer does not relax completely until the potential difference drops below 3 volts in this example. Thus the movable reflective layer, in this example, cannot directly transition from the 5 volt state to the 4 volt state. Rather, it has to first transition to a state below 3 volts, then transition to the 4 volt state.
In
In some implementations, movable element 870 at a position associated with the color white may not be able to directly transition to some colors until movable element 870 is “released” from the hysteresis. Releasing movable element 870 from hysteresis may involve positioning movable 870 out of a hysteresis loop (i.e., to a color outside of the hysteresis loop) that may be preventing movable element 870 from directly moving to particular positions within the hysteresis loop. After movable element 870 is released, the two-part technique may be applied. Therefore, transitioning to some positions and colors may need a three-part technique including releasing movable element 870 from hysteresis, driving movable element 870 towards the intended position, and stabilizing to the intended position.
For example, in
In additional detail,
However, not all positions and colors may be within the hysteresis region. For example, in
In
Voltage LUTs 1610 may include LUTs providing information for applying three voltages to Vd electrode 860.
In
For a movable element 870 in the hysteresis region (e.g., at the color white) and transitioning to another position within the hysteresis region, the first voltage in a first LUT may indicate the voltage to be applied to release movable element 870. The second voltage in a second LUT may indicate the voltage to position movable element 870 to the position associated with the intended color. The third voltage in a third LUT may indicate the voltage to stabilize movable element 870 to the position associated with the intended color.
For a movable element 870 initially outside of the hysteresis region or transitioning to a subsequent position outside of the hysteresis region, the first voltage in the first LUT may indicate the voltage to apply to position movable element 870 towards the position associated with the intended color. The second voltage in the second LUT may indicate the voltage to apply to stabilize movable element 870 to the intended position. The third voltage in the third LUT may be the same as the second voltage. Since movable element 870 need not be released from a hysteresis region, only two different applications of voltages are needed, and therefore, the third voltage may be a repeat of the second voltage. In other implementations, the first application of voltage may be applied twice instead.
For a movable element 870 staying at the same position and color, each voltage indicated in each of the three LUTs may be the same such that movable element 870 does not move to another position.
For example, in
In
A transition from green-to-green should apply 5 V to Vd electrode 860, which may be a voltage already applied to it because movable element 870 should not move. Accordingly, each of the LUTs in
In
The LUTs may be organized in different ways.
The above examples of voltages are provided for illustrative purposes. Other implementations may involve other voltages and/or LUTs.
In some implementations, the three voltages may be applied in three different “rips” through each row of display units 750 of the display. For example, in a first rip, each Vd electrode 860 of each display unit 750 in a first row may be applied the first voltage as indicated in the first LUT, followed by each movable element 870 of each display unit 750 in a second row, and so on, until each Vd electrode 860 of each display unit 750 is biased to allow for the corresponding movable element 870 to be released (if in the hysteresis region and transitioning to another position and color in the hysteresis region), driven towards the intended position and color (if transitioning to a position and color outside of the hysteresis region), or be maintained (if the color should not change). Next, each row, row-by-row, may be applied the second voltage as indicated in the second LUT. After each row in the display is provided the second voltage, each row may then be provided the voltages as indicated in the third LUT.
Additionally, the polarities of the electric fields of display unit 750 may also be switched between rips. For example, if Vcom electrode 865 is 0 V and the voltages indicated in the LUTs are provided to the Vd electrode 860, the voltage applied to Vbias electrode 855 may alternate between a positive and negative voltage (e.g., 12 V and −12 V) to reverse the directions of the electric fields, and therefore, reduce charge accumulation across display unit 750. For example, the voltage applied to Vbias electrode 855 may switch before or after an application of voltage to Vd electrode 860.
In some implementations, the third rip may not be performed. In particular, the second rip may stabilize movable element 870 for colors outside of hysteresis. For colors within hysteresis and transitioning to another color within hysteresis, enough stability may be provided by first releasing to the position and color outside of the hysteresis region. However, in other implementations, applications of the third rip may be repeated to provide further stability.
Though only three LUTs are shown in the preceding examples, more LUTs may be used. For example, additional LUTs may be used to further take into account polarities. For example, a positive frame with display units 750 having a positive polarity may transition to a negative frame with display units 750 having a negative polarity, and vice versa. The transitions to the same positions and colors, but with different polarities, may have different LUTs.
Additionally, the LUTs may indicate any number of colors that may be transitioned from or towards. For example, the LUTs herein include eight colors, but any number of colors may be used by the LUTs.
The display device 40 includes a housing 41, a display 30, an antenna 43, a speaker 45, an input device 48 and a microphone 46. The housing 41 can be formed from any of a variety of manufacturing processes, including injection molding, and vacuum forming. In addition, the housing 41 may be made from any of a variety of materials, including, but not limited to: plastic, metal, glass, rubber and ceramic, or a combination thereof. The housing 41 can include removable portions (not shown) that may be interchanged with other removable portions of different color, or containing different logos, pictures, or symbols.
The display 30 may be any of a variety of displays, including a bi-stable or analog display, as described herein. The display 30 also can be configured to include a flat-panel display, such as plasma, EL, OLED, STN LCD, or TFT LCD, or a non-flat-panel display, such as a CRT or other tube device. In addition, the display 30 can include an IMOD-based display, as described herein.
The components of the display device 40 are schematically illustrated in
The network interface 27 includes the antenna 43 and the transceiver 47 so that the display device 40 can communicate with one or more devices over a network. The network interface 27 also may have some processing capabilities to relieve, for example, data processing requirements of the processor 21. The antenna 43 can transmit and receive signals. In some implementations, the antenna 43 transmits and receives RF signals according to the IEEE 16.11 standard, including IEEE 16.11(a), (b), or (g), or the IEEE 802.11 standard, including IEEE 802.11a, b, g, n, and further implementations thereof. In some other implementations, the antenna 43 transmits and receives RF signals according to the Bluetooth® standard. In the case of a cellular telephone, the antenna 43 can be designed to receive code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), Global System for Mobile communications (GSM), GSM/General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio (TETRA), Wideband-CDMA (W-CDMA), Evolution Data Optimized (EV-DO), 1×EV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), Evolved High Speed Packet Access (HSPA+), Long Term Evolution (LTE), AMPS, or other known signals that are used to communicate within a wireless network, such as a system utilizing 3G, 4G or 5G technology. The transceiver 47 can pre-process the signals received from the antenna 43 so that they may be received by and further manipulated by the processor 21. The transceiver 47 also can process signals received from the processor 21 so that they may be transmitted from the display device 40 via the antenna 43.
In some implementations, the transceiver 47 can be replaced by a receiver. In addition, in some implementations, the network interface 27 can be replaced by an image source, which can store or generate image data to be sent to the processor 21. The processor 21 can control the overall operation of the display device 40. The processor 21 receives data, such as compressed image data from the network interface 27 or an image source, and processes the data into raw image data or into a format that can be readily processed into raw image data. The processor 21 can send the processed data to the driver controller 29 or to the frame buffer 28 for storage. Raw data typically refers to the information that identifies the image characteristics at each location within an image. For example, such image characteristics can include color, saturation and gray-scale level.
The processor 21 can include a microcontroller, CPU, or logic unit to control operation of the display device 40. The conditioning hardware 52 may include amplifiers and filters for transmitting signals to the speaker 45, and for receiving signals from the microphone 46. The conditioning hardware 52 may be discrete components within the display device 40, or may be incorporated within the processor 21 or other components.
The driver controller 29 can take the raw image data generated by the processor 21 either directly from the processor 21 or from the frame buffer 28 and can re-format the raw image data appropriately for high speed transmission to the array driver 22. In some implementations, the driver controller 29 can re-format the raw image data into a data flow having a raster-like format, such that it has a time order suitable for scanning across the display array 30. Then the driver controller 29 sends the formatted information to the array driver 22. Although a driver controller 29, such as an LCD controller, is often associated with the system processor 21 as a stand-alone Integrated Circuit (IC), such controllers may be implemented in many ways. For example, controllers may be embedded in the processor 21 as hardware, embedded in the processor 21 as software, or fully integrated in hardware with the array driver 22.
The array driver 22 can receive the formatted information from the driver controller 29 and can re-format the video data into a parallel set of waveforms that are applied many times per second to the hundreds, and sometimes thousands (or more), of leads coming from the display's x-y matrix of display elements.
In some implementations, the driver controller 29, the array driver 22, and the display array 30 are appropriate for any of the types of displays described herein. For example, the driver controller 29 can be a conventional display controller or a bi-stable display controller (such as an IMOD display element controller). Additionally, the array driver 22 can be a conventional driver or a bi-stable display driver (such as an IMOD display element driver). Moreover, the display array 30 can be a conventional display array or a bi-stable display array (such as a display including an array of IMOD display elements). In some implementations, the driver controller 29 can be integrated with the array driver 22. Such an implementation can be useful in highly integrated systems, for example, mobile phones, portable-electronic devices, watches or small-area displays.
In some implementations, the input device 48 can be configured to allow, for example, a user to control the operation of the display device 40. The input device 48 can include a keypad, such as a QWERTY keyboard or a telephone keypad, a button, a switch, a rocker, a touch-sensitive screen, a touch-sensitive screen integrated with the display array 30, or a pressure- or heat-sensitive membrane. The microphone 46 can be configured as an input device for the display device 40. In some implementations, voice commands through the microphone 46 can be used for controlling operations of the display device 40.
The power supply 50 can include a variety of energy storage devices. For example, the power supply 50 can be a rechargeable battery, such as a nickel-cadmium battery or a lithium-ion battery. In implementations using a rechargeable battery, the rechargeable battery may be chargeable using power coming from, for example, a wall socket or a photovoltaic device or array. Alternatively, the rechargeable battery can be wirelessly chargeable. The power supply 50 also can be a renewable energy source, a capacitor, or a solar cell, including a plastic solar cell or solar-cell paint. The power supply 50 also can be configured to receive power from a wall outlet.
In some implementations, control programmability resides in the driver controller 29 which can be located in several places in the electronic display system. In some other implementations, control programmability resides in the array driver 22. The above-described optimization may be implemented in any number of hardware and/or software components and in various configurations.
As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.
The various illustrative logics, logical blocks, modules, circuits and algorithm steps described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and steps described above. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system.
The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular steps and methods may be performed by circuitry that is specific to a given function.
In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage media for execution by, or to control the operation of, data processing apparatus.
If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. The steps of a method or algorithm disclosed herein may be implemented in a processor-executable software module which may reside on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program from one place to another. A storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer. Also, any connection can be properly termed a computer-readable medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above also may be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine readable medium and computer-readable medium, which may be incorporated into a computer program product.
Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein. Additionally, a person having ordinary skill in the art will readily appreciate, the terms “upper” and “lower” are sometimes used for ease of describing the figures, and indicate relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of, e.g., an IMOD display element as implemented.
Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, a person having ordinary skill in the art will readily recognize that such operations need not be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.
| Number | Name | Date | Kind |
|---|---|---|---|
| 8102592 | Ji | Jan 2012 | B2 |
| 20020054424 | Miles | May 2002 | A1 |
| 20040218341 | Martin | Nov 2004 | A1 |
| 20040227493 | Van et al. | Nov 2004 | A1 |
| 20060066926 | Kwak | Mar 2006 | A1 |
| 20090201282 | Govil | Aug 2009 | A1 |
| 20130050165 | Northway et al. | Feb 2013 | A1 |
| 20130135324 | Hong et al. | May 2013 | A1 |
| 20130135364 | Govil | May 2013 | A1 |
| 20130135705 | Hong et al. | May 2013 | A1 |
| 20130321379 | Van et al. | Dec 2013 | A1 |
| 20140092110 | Chan et al. | Apr 2014 | A1 |
| Entry |
|---|
| International Search Report and Written Opinion—PCT/US2016/016166—ISA/EPO—dated Mar. 24, 2016. |
| Number | Date | Country | |
|---|---|---|---|
| 20160247463 A1 | Aug 2016 | US |
