Patent Application
20140106684
This disclosure relates generally to antennas and more particularly to transparent antennas on a display device, such as an electromechanical systems (EMS) display device.
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.
Many mobile display devices such as cellular phones, smart phones, e-readers, and tablet computers have increasingly limited space to place antennas for wireless communications, while demands for higher data rates and operation over multiple bands and protocols have increased. To avoid interfering with images formed on a display device, antennas are conventionally buried inside or attached to a sidewall of an enclosure, or may protrude from a body of the display device. In part because mobile display devices are increasingly required to accommodate features such as GPS, Wi-Fi, and NFC in addition to one or more cellular bands along with higher data transfer rates, alternative antenna configurations and placements are being explored.
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 display device. The display device can include a transparent substrate through which an image can be displayed, where the transparent substrate includes a surface having a display region and a non-display region that surrounds at least a portion of a perimeter of the display region. The display device also can include a first antenna formed in the display region of the transparent substrate, where the first antenna is substantially transparent, and a second antenna cooperatively coupled with the first antenna.
In some implementations, the first and the second antennas are spatially diverse. In some implementations, the second antenna is formed on the same surface of the transparent substrate as the first antenna. In some implementations, the display device further includes one or more electrically conductive traces formed on the first antenna, where the electrically conductive traces are configured to electrically reinforce the first antenna. In some implementations, the display device further includes a printed circuit board in electrical communication with the first antenna, where the second antenna is physically connected to the printed circuit board. The first antenna may be configured for receiving wireless signals and the second antenna may be configured for transmitting wireless signals. In some implementations, the second antenna is substantially non-transparent. In some implementations, the first antenna and the second antenna form part of a multiple-input multiple-output (MIMO) antenna configuration. In some implementations, the first antenna includes a transparent conductive oxide.
Another innovative aspect of the subject matter described in this disclosure can be implemented in a display device. The display device can include means for displaying an image, means for receiving a wireless signal disposed on a surface of the displaying means, and means for transmitting a wireless signal cooperatively coupled to the receiving means. The receiving means is substantially transparent.
In some implementations, the display device further includes a printed circuit board in electrical communication with the transmitting means, where the transmitting means is physically connected to the printed circuit board. In some implementations, the display device further includes means for switching, where the switching means is configured to selectively switch between the transmitting means and the receiving means.
Another innovative aspect of the subject matter described in this disclosure can be implemented in a method of manufacturing a display device. The method can include providing a transparent substrate through which an image can be displayed, where the transparent substrate includes a surface having a display region and a non-display region that surrounds at least a portion of a perimeter of the display region. The method also can include forming a first antenna in the display region of the transparent substrate, and coupling cooperatively a second antenna with the first antenna. The first antenna is substantially transparent and the second antenna is substantially non-transparent.
In some implementations, the method further includes providing a printed circuit board in electrical communication with the first antenna, where the second antenna is physically connected to the printed circuit board, and providing a display element between the printed circuit board and the first transparent antenna. In some implementations, the first and the second antennas have at least one of spatial diversity, temporal diversity, frequency diversity, and polarization diversity with each other.
Another innovative aspect of the subject matter described in this disclosure can be implemented in a method of operating a display device. The method can include detecting a head of a user. The method also can include switching from a display-side antenna disposed on an exterior surface of the display device to an enclosure antenna disposed on an interior surface of the display device when the detected head is proximate the display-side antenna. The method also can include transmitting a wireless signal from the enclosure antenna.
In some implementations, detecting the head of the user can include detecting with a proximity sensor. In some implementations, the exterior surface includes a display region and a non-display region that surrounds a perimeter of the display region, where the display-side antenna includes one or more transparent antennas in the display region. In some implementations, the exterior surface includes a display region and a non-display region that surrounds at least a portion of a perimeter of the display region, where the display-side antenna includes one or more non-transparent antennas in the non-display region.
Another innovative aspect of the subject matter described in this disclosure can be implemented in a machine-readable, non-transitory storage medium comprising computer executable instructions for operating a display device. The instructions can include detecting a head of a user, switching from a display-side antenna disposed on an exterior surface of the display device to an enclosure antenna disposed on an interior surface of the display device when the detected head is proximate the display-side antenna, and transmitting a wireless signal from the enclosure antenna.
In some implementations, the computer executable instructions are configured to control one or more processors, where the one or more processors are operatively coupled to a proximity sensor configured to detect the head of the user.
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.
Some implementations described herein relate to display devices with one or more antennas on a transparent substrate through which a display may be viewed. The one or more antennas on the transparent substrate may be substantially transparent to allow suitable viewing of an underlying display. In some implementations, narrow electrically conductive traces may serve as the antenna or the electrically conductive traces may augment the performance of an antenna formed from a transparent conductive film. The electrically conductive traces may augment the performance of the antenna by electrically reinforcing it. In some implementations, the antenna may be transparent and cooperatively coupled with a second antenna that may or may not be transparent. The antenna may cooperatively couple with the second antenna by having both antennas used together in a single system, under control of a single system, used interchangeably, or used independently or together within a single system. In some implementations, the second antenna may lie in a non-display region of the transparent substrate. In some implementations, the second antenna may be positioned within an enclosure of the display device, such as on a printed circuit board or on a sidewall or interior surface of the enclosure. In some implementations, multiple antennas on the transparent substrate may provide access to one or more cellular or non-cellular wireless bands. In some implementations, multiple antennas may be configured in front of or behind the display to provide enhanced data transfer rates through adaptive antenna arrays, beam forming, or multiple-input multiple-output based (MIMO-based) wireless communications.
Particular implementations of the subject matter described in this disclosure may be implemented to realize one or more of the following potential advantages. The use of a transparent antenna increases the regions for suitable placement of an antenna in a display device, by allowing placement in regions where an image may be displayed. Multiple antennas may be formed on a display device or positioned in an enclosure of the display device so that the wireless communication system may benefit from antenna diversity, such as, for example, spatial, frequency, temporal, or polarization diversity, etc. Antenna diversity is the use of two or more antennas to improve the quality and reliability of a wireless signal. While a transparent antenna alone may have less than desirable antenna gain resulting from the relatively low electrical conductivity of most transparent conductive materials, in some implementations a transparent antenna augmented or electrically reinforced with narrow, electrically conductive traces may improve the overall antenna efficiency. A transparent antenna cooperatively coupled with one or more antennas on the display or within the enclosure of the display device may provide increased channel capacity for higher data rates and/or improved system performance with increased spatial, frequency, temporal, or polarization diversity. For example, a transparent antenna cooperatively coupled with a second antenna may increase the frequency bands over which the display device operates.
A transparent antenna cooperatively coupled with a second antenna may provide multiple operating modes by allowing the selective switching between antennas. In some implementations, a display-side antenna and an enclosure antenna may be selectively switched to receive the signal with the highest signal level. In some implementations, a display-side antenna may be used to receive low-level signals and an enclosure antenna may be used to transmit high-level signals. In some implementations, an enclosure antenna may be used for transmission when a user's face or head is detected near a display-side antenna. In some implementations, two, three, four or more antennas may be positioned on the display side of the display device, optionally cooperatively coupled with one or more antennas within the enclosure of the display device and switched accordingly to achieve increased uplink and downlink data rates using MIMO (multiple-input, multiple-out) configurations, beam-forming, or adaptive antenna arrays.
In some implementations, a transparent antenna electrically reinforced with electrically conductive traces or cooperatively coupled with a transparent or non-transparent antenna may be formed on or over a display device, such as, for example, an EMS or MEMS display device, or other type of display device such as an LCD, OLED, or electrophoretic display. 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.
In recent years, wireless communications have become more widespread in display devices, including EMS and MEMS display devices. Specialized antennas are incorporated in mobile display devices to respond to increasing demands in wireless communications. However, with the performance of display devices becoming higher and the size of some display devices becoming smaller, the space for allocating antennas is becoming increasingly limited.
Furthermore, an increasingly larger group of communication frequencies has proliferated, including non-cellular wireless standards such as global positioning systems (GPS), Bluetooth protocols, wireless local area networks (WLAN), Wi-Fi networks, worldwide interoperability for microwave access (WiMax) networks, radio frequency identification (RFID), near field communications (NFC), high-definition television (HDTV), frequency modulation (FM) broadcast radio, multiple-input multiple-output (MIMO) systems, and ultra-wide band (UWB) protocols. Some of the frequency bands related to these standards and others are going to higher frequencies, such as 2-5 GHz, 5-10 GHz and higher, such as in the 60 GHz range.
In addition, demand for higher data rates has grown. With larger amounts of data being transmitted wirelessly, display devices are being adapted for increased channel capacity for reliably transmitting data over one or more communication channels. However, the channel capacity of a display device may be limited by the type, quality, size, placement, and quantity of the associated antennas.
Transparent antennas positioned on or over a display may provide greater amounts of space to allocate one or more antennas. However, many transparent antennas, such as those made of indium-tin-oxide (ITO), have relatively low electrical conductivity that can result in low antenna efficiency. While transparent antennas based on an electrically conductive oxide alone may not be able to meet the increasing demands for more frequency bands and higher data rates, the transparent antennas may be cooperatively coupled with another transparent or non-transparent antenna or otherwise augmented to improve antenna and overall system performance. Cooperatively coupling an antenna with another antenna as used herein may define using the antennas together in a single system or as part of a single device, using the antennas under the control of a single system, using the antennas interchangeably under a single system, or operating the antennas independently or together in a single system. Augmenting an antenna as used herein may define electrically reinforcing the antenna to improve antenna performance.
In some implementations, the performance and capability of a mobile display device may be improved by increasing the channel capacity for transferring data wirelessly. Methods to increase the channel capacity include increasing the bandwidth of the communication link, improving the signal-to-noise (S/N) ratio for the system, or adding antennas with adequate diversity to either or both sides of the link (upstream and downstream).
C=B*log2(1+S/N)
with the bandwidth B in Hertz and the channel capacity C in bits per second. Hence, achieving higher data rates may involve increasing the signal bandwidth or increasing the S/N ratio. The use of MIMO systems with multiple antennas may further increase the channel capacity. MIMO antenna systems may use multiple antennas at the transmitter and the receiver end. Multiple independent data streams may be transmitted and received by the antennas at each end of the link. Note that the number of streams may be less than or equal to the lower of the number of antennas at either end. The Shannon-Hartley capacity theorem may be modified in MIMO antenna systems to include the number of streams M.
C=M*B*log2(1+S/N)
In
Multiple antenna schemes are not limited to MIMO antenna configurations. Multiple antenna schemes may also take advantage of antenna diversity to improve overall device performance. The basic concept of antenna diversity is to transmit a signal via several independent paths to get independent signal copies at the receiver via spatial diversity, frequency diversity, temporal diversity, polarization diversity, and/or other diversity types. This may mitigate the undesirable effects of fading and other types of attenuation loss, and allow the receiver to select the signal with the highest signal quality. Signal quality can be evaluated based on various quantities and/or parameters, including, but not limited to, signal-to-noise ratio, signal strength, bit error rate, data transmission rate, and fading condition.
Spatial diversity may employ multiple antennas that are physically separated from one another, which may be on the order of about one to five wavelengths or more apart. Spatial diversity may improve the robustness of the signal by providing multiple copies of the same signal propagating in space. This may reduce the probability that different signal paths between the transmitter and the receiver undergo the same amount of fading, for example. Spatial diversity may be achieved using multiple transmitter antennas and/or multiple receiving antennas. Spatial diversity may also be a part of a MIMO antenna system.
To benefit from frequency diversity, signals may be transmitted over multiple channels having different carrier frequencies, or the signal may be spread over a wide spectrum that may have portions affected by frequency-dependent fading or attenuation. Antenna configurations and systems that transmit the signal over different frequencies may reduce the effects of frequency-dependent fading or attenuation, for example.
Temporal or time diversity involves transmitting the same parts of a signal at different instances in time. Temporal diversity may be used to reduce the effects of error bursts due to time-varying channel conditions, which may be caused by fading in combination with a moving receiver, transmitter, or obstacle, or by intermittent electromagnetic interference or co-channel interference.
Polarization diversity takes multiple versions of the signal and transmits them with different polarizations. In some implementations, the antennas may be linearly polarized (e.g., horizontal/vertical) or circularly polarized (left-hand or right-hand), although other polarizations (e.g., elliptical) are possible. Pairs of antennas may be configured to have orthogonal polarizations that may result in increased signal strength from one or the other. By pairing complementary polarizations, an antenna array may be further immunized from polarization mismatches and signal fading.
Many display devices, including cellular phones, smart phones, e-readers, and tablet computers, have limited space to position antennas for wireless communications. Antennas may be limited to incorporation in or on the device enclosure, which generally limit antenna gain, efficiency, and directionality. These limitations on antenna configurations may further restrict opportunities to take advantage of antenna diversity and spatial multiplexing, as discussed earlier herein, as well as opportunities for beam steering and adaptive antenna arrays.
In some implementations, antennas may be placed on or in front of a display of a display device.
As illustrated in the example in
In some implementations, the antenna 220 may be transparent or substantially transparent. A transparent antenna may include an antenna made of a transparent conductive material, such as a transparent conductive oxide. For example, a transparent conductive oxide may include ITO. In some implementations, a transparent antenna may include an antenna made of very narrow electrically conductive traces, such as a mesh structure of electrically conductive material, irrespective of whether the electrically conductive material is transparent itself. In some implementations, the transparent antenna may include an antenna formed from a transparent conductive material that is augmented or electrically reinforced with narrow traces of conductive material (which may be non-transparent). Transparency as used herein is defined as transmittance of visible light of about 70% or more, such as about 80% or more or about 90% or more. An empirical definition of transparency for the transparent antenna is the fraction of light transmitted through the transparent antenna at which a displayed image may still be effectively viewed by a viewer. With highly emitting OLED displays or with high-intensity backlights for LCD displays, the transparency of the antenna panel may be below about 70% and still be considered transparent or substantially transparent.
The display device 200 may further include one or more antenna feed lines 240 connected to the antenna 220. The antenna feed lines 240 allow electrical connections between a radio transmitter or receiver and the antenna 220. The antenna feed lines 240 may provide radio frequency (RF) current or voltage from the transmitter to the antenna 220, or transfer RF current or voltage from the antenna 220 to the receiver. In some implementations, the antenna feed lines 240 may include but are not limited to a coaxial cable, a twin-lead cable, a twisted pair, a wire, a cable, a flex tape, a transmission line, an impedance-matched flex tape, a coplanar waveguide, or a through-substrate via. The antenna feed lines 240 may be attached to the transparent substrate 210 with solder, anisotropic conductive film (ACF), a clamp, a socket, or other suitable technique.
The transparent antenna 320 may be electrically coupled to a ground plane 350. In the example illustrated in
A through-substrate via (TSV) 330 or through-glass via (TGV) may extend between two sides of the transparent substrate 310 to provide backside electrical interconnection to the transparent antenna 320 as shown in
The transparent antenna 320 may be made of a transparent conductive material such as ITO. Thus, the transparent antenna 320 may be positioned in a display region of the transparent substrate 310. However, as transparent conductive materials typically have high resistivity, the transparent conductive material may unduly attenuate a radio-frequency signal, resulting in low antenna gain. Therefore, a transparent antenna 320 such as the patch antenna illustrated in
Since the transparent antenna 320 formed of a transparent conductive oxide such as ITO may conduct electricity relatively poorly, the electrically conductive traces 360 may electrically reinforce the transparent antenna 320. In some implementations, the electrically conductive traces 360 may be made of lower resistivity material than the transparent antenna 320. In some implementations, the electrically conductive traces 360 may have a greater thickness than the transparent antenna 320. In some implementations, the electrically conductive traces 360 may modify the local and overall impedance of the transparent antenna, lowering the resistance to reduce internal losses and improving matching with free space to reduce transmission and receiving losses. Therefore, the electrically conductive traces 360 may electrically reinforce the transparent antenna 320 to reduce antenna losses.
In some implementations, the electrically conductive traces 360 may be formed in a non-display region of the transparent substrate 310. The transparent substrate 310 may include a surface having a display region and a non-display region that surrounds at least a portion of the perimeter of the display region. Thus, the electrically conductive traces 360 may avoid occluding an image (not shown) in the display region of the transparent substrate 310 by placing the traces in the non-display region, such as to provide low-resistance feed lines or to selectively reinforce the transparent antenna in regions outside of the display region. In addition, the width of the electrically conductive traces 360 may be between about a few micrometers and several millimeters. Hence, the electrically conductive traces 360 may improve the antenna performance without obstructing a users' view of the display region, regardless of whether the electrically conductive traces 360 are in the display region or non-display region of the transparent substrate 310.
In some implementations, the electrically conductive traces 360 may be very narrow and made of relatively low-resistivity metals. For example, the electrically conductive traces 360 may include at least one of aluminum, an aluminum alloy, aluminum-silicon, copper, chromium, molybdenum, molybdenum-chromium, or silver. Though the electrically conductive traces 360 may be made of material that is non-transparent to visible light, the electrically conductive traces 360 may be sufficiently narrow to appear to be substantially transparent to a viewer of the display. For example, the width of the electrically conductive traces 360 may be between about 10 nm and about 10 μm or larger, and typically between about 1 μm and about 5 μm for patterned features. Some configurations may include thin meshes of copper and/or silver nanowires. The electrically conductive traces 360 may be positioned in the display region of the transparent substrate 310 without substantially interfering with images formed in the display region. In some implementations, the electrically conductive traces 360 may be formed from a multi-layer composite of materials including an absorber, a dielectric, and a reflector, with the dielectric serving as an optical cavity between the absorber and the reflector. The material stack is sometimes referred to as a black matrix, a black mask, a substantially black interferometric stack structure, or a black stack. To a viewer, this combination appears dark or substantially black. Dark features may aid in retaining the contrast of an underlying display.
In some implementations, the transparent antennas 320a and 320b may be spaced apart to provide spatial diversity. By having multiple antennas 320a and 320b on the transparent substrate 310 with spatial diversity, the robustness and data rates of wireless transmissions may improve. In some implementations, the transparent antenna 320b is arranged in a rotated configuration from the transparent antenna 320a. Flipped or rotated antenna configurations may allow feed lines for each antenna to be located at the periphery of the transparent substrate 310 for ready connection with external circuitry.
In some implementations, each of the transparent antennas 320a and 320b may have one or more slots formed in the transparent antennas 320a and 320b. Each of the slots may correspond to different operating frequencies to allow multi-band operation and/or frequency diversity in the transparent antennas 320a and 320b. By having one or more slots, multiple communication bands may be accommodated with the same antenna. In the example illustrated in
In some implementations, the transparent antennas 320a and 320b may have different operating frequencies. With higher frequencies, the size of the antenna generally reduces. At frequencies between about 2-3 GHz to about 60 GHz and above, one or more transparent antennas 320a and 320b may be readily placed on the transparent substrate 310 for use in front of a display of a mobile display device. At higher frequencies where the current density occurs increasingly closer to the surface of a conductor, the skin depth for the RF excitations is reduced, allowing the use of a relatively thin conductive film with minimal loss. The transparent antennas 320a and 320b may have different operating frequencies. Either or both transparent antennas 320a and 320b may accommodate one or more standards or protocols including but not limited to GPS, a Bluetooth protocol, WLAN, a Wi-Fi network, a WiMax network, an RFID band, an NFC band, an HDTV band, an FM band, a MIMO system, or a UWB protocol. Although shown with two antennas 320a and 320b, three or more antennas of the same or different type may be included on the transparent substrate 310.
In some implementations, one or more electrically conductive traces 360 may be formed on portions of or throughout the transparent antennas 320a and 320b to improve the antenna performance. The electrically conductive traces 360 may electrically reinforce the transparent antennas 320a and 320b, increasing the effective conductivity of the antennas 320a and 320b in places where the electrically conductive traces 360 are located, such as near bends or interior corners of the antennas 320a and 320b where the current density is larger. The transparent antennas 320a and 320b may be formed of different materials from the electrically conductive traces 360. In some implementations, the electrically conductive traces 360 may be made of lower resistivity material than the transparent antennas 320a and 320b or have a greater thickness than the transparent antennas 320a and 320b. For example, ITO may have a resistivity of about 9.3 ohm-cm, whereas copper and aluminum may have resistivities between about 1.7×10−6 and 2.8×10−6 ohm-cm. Generally, the electrically conductive traces 360 lower the impedance of the transparent antennas 320a and 320b in regions where the traces are located. Therefore, where the resistivity or resistance of each of the non-reinforced transparent antennas 320a and 320b is too high, the electrically conductive traces 360 may locally and electrically reinforce parts of the transparent antennas 320a and 320b to reduce antenna losses and improve antenna matching.
In some implementations, the electrically conductive traces 360 may be formed in a non-display region of the transparent substrate 310. The width of electrically conductive traces 360 in a non-display region may be wider than those in a display region, as no portions of a displayed image are blocked. For example, the width of the electrically conductive traces 360 may extend from a few microns to a few millimeters wide or more for many display devices. In some implementations, the electrically conductive traces 360 may form part of a low-resistivity metal grid or mesh in the display region or the non-display region of the transparent substrate 310. The electrically conductive traces 360, in some implementations, may have widths between about 1 μm and about 10 μm. In some implementations, the width of the electrically conductive traces 360 may be reduced in the display region compared to the width of the electrically conductive traces 360 in the non-display region, such that the electrically conductive traces 360 in the display region are less visible to a viewer of the display. Other techniques may be applied to reduce the visibility of the electrically conductive traces 360 in either the display region or the non-display region. For example, the electrically conductive traces 360 may be formed from a grid of a black interferometric stack structure, such that the traces appear dark or substantially black to a viewer. In another example, the electrically conductive traces 360 may have curvilinear features such as successively interconnected arcs or randomized segments that make the traces 360 less visible to a viewer.
In some implementations, the electrically conductive traces 360 may be formed in regions of high current density in the transparent antennas 320a and 320b. Regions of high current density may occur where the transparent antennas 320a and 320b have slots and/or bends. Such regions may be electrically reinforced with electrically conductive traces 360. Thus, the electrically conductive traces 360 may be formed proximate to slots and/or bends in the transparent antennas 320a and 320b.
In the example in
A portion of the transparent antennas 320a and 320b may be in direct electrical communication with a portion of the ground plane 350. For example, a transparent TGV or TSV (not shown) may extend through the transparent substrate 310 and electrically connect the transparent antennas 320a and 320b directly with a portion of the ground plane 350. Radio-frequency signals may be applied to each antenna 320a and/or 320b via one or more feed lines 370 and 380. In some implementations, feed line 370 serves as a ground line and feed line 380 serves as a signal line. In some implementations, feed lines 370 and 380 are differentially driven or differentially received. External connections are generally provided between transparent antennas 320a and 320b and associated RF transmitter and receiver circuitry. For example, feed lines 370 and 380 may be connected to a duplexer. In one example, feed lines 370 and 380 for one or both transparent antennas 320a and 320b are connected to external RF circuitry via an impedance-matched flex tape. Other examples for connection with the transparent antennas 320a and 320b include a coaxial cable, a twin-lead cable, a twisted pair, a wire, a cable, a flex tape, a transmission line, a waveguide, or other suitable means.
The transparent antenna 320c may be a patch antenna as illustrated in the example of
For example, the transparent or non-transparent antennas 320e may include one or more folded dipole antennas as illustrated in the example of
The transparent or non-transparent antennas 320e may be formed at the corners or along the sides of the transparent substrate 310. The transparent antenna 320c and the transparent or non-transparent antennas 320e may be arranged as an array of antennas. Each of the antennas may have at least one of spatial diversity, frequency diversity, temporal diversity, polarization diversity, and other diversity type with the other antennas in the array. In some implementations, each of the transparent or non-transparent antennas 320e may be spatially diverse from one another. In some implementations, the transparent or non-transparent antennas 320e may form part of a MIMO antenna array for spatial multiplexing. This may increase the data rates for wireless communications by two-fold, four-fold, ten-fold, or more. In some implementations, multiple transparent or non-transparent antennas 320e may be used for beam-steering or beam-forming to improve RF signal transmissions.
The transparent substrate 410 may be formed or otherwise positioned over a display element 425. In some implementations, the display element 425 may be a reflective display element, a transmissive display element, or self-emitting display element. For example, the display element 425 may be an IMOD, LCD, OLED, or other type of display. The display element 425 may be enclosed between a backplane 470 (e.g., a back glass, back plate or backlight) and a display substrate 460 (e.g., a display glass), which may protect the display element 425 from external conditions.
The first antenna 420 may be positioned between the transparent substrate 410 and a cover plate 430. The cover plate 430 may protect the first antenna 420 from ambient conditions and provide scratch protection. While shown on a separate substrate 410, the first antenna 420 may be formed on other parts of the display device 400 such as the cover plate 430, display substrate 460, or backplane 470.
In some implementations, the display device 400 may further include a printed circuit board (PCB) 480 under or behind the display element 425. The PCB 480 may be spaced apart from the display element 425 and the cover plate 430, and enclosed within the display device 400. The PCB 480 may be in electrical communication with the first antenna 420. The PCB 480 may further include an RF module 482 and a processor 484.
A second antenna 450 may be mounted on or otherwise connected to the PCB 480. As illustrated in the example of
The second antenna 450 may be positioned below or behind the display element 425, as illustrated in
A substantially non-transparent antenna mounted or otherwise connected to the PCB 480, such as the second antenna 450, is typically small to reduce weight and area on the PCB 480. However, this configuration can reduce direct exposure to incident and transmitted wireless signals because the antenna is buried inside an enclosed space that may have a large number of metallic elements nearby. As a result, the second antenna 450 by itself may experience reduced antenna gain when in an enclosure of the display device 400.
Cooperatively coupling the first antenna 420 with one or more second antennas 450 may increase overall system performance by providing antenna diversity. The first antenna 420 and the second antenna 450 may have at least one of spatial diversity, temporal diversity, frequency diversity, polarization diversity, and other diversity type. In addition, the first antenna 420 and the second antenna 450 may provide opportunities for beam steering and adaptive antenna arrays. Beam steering can increase the effective RF signal strength by directing RF energy selectively towards a receiving antenna, allowing higher signal-to-noise ratios and/or a reduction in transmitting power. Adaptive antenna arrays allow one or more antennas in an array to selectively transmit and receive signals with increased directionality.
Cooperatively coupling the first antenna 420 with the second antenna 450 may increase the channel capacity of the display device 400 via MIMO. In some implementations, the RF module 482 of display device 400 may be configured to selectively switch between the first antenna 420 and the second antenna 450 for receiving (e.g., downloading) and transmitting (e.g., uploading). In some implementations, the first antenna 420 on the transparent substrate 410 may be configured for receiving wireless signals while the second antenna 450 connected to the PCB 480 may be configured for transmitting wireless signals. For example, a display-side antenna or first antenna 420 may be used for improved reception of RF signals while a PCB antenna or second antenna 450 is used for higher-power transmissions from display device 400 to reduce the exposure of RF power to a user. In some implementations, the first antenna 420 or the second antenna 450 may be selected for reception when the signal strength from each antenna has been determined. In some implementations, the transmit frequencies may be different than the receive frequencies, and the antenna 420 or 450 may be selected for transmission or reception based on the frequency. In some implementations with one or more display-side antennas (e.g., first antenna 420) and optionally an enclosed antenna (e.g., second antenna 450), MIMO may be used to increase the transfer rate of data.
Generally, a MIMO system configuration combines multiple transmit antennas and/or multiple receive antennas for the transmission of multiple independent data streams. In some implementations, the first antenna 420 may be part of an array of receive antennas, and the second antenna 450 may be part of an array of transmit antennas, or vice versa. In some implementations, the first antenna 420 and the second antenna 450 may both be a part of an array of receive or transmit antennas.
As shown in
In some implementations, the display device 400 may include a proximity sensor (not shown). A proximity sensor such as a camera or an infrared sensor may be configured to provide input to a controller or processor to allow selective switching of the first antenna 420 and the second antenna 450 for RF transmissions. For example, when the proximity sensor detects a user's head or body proximate to a surface of the transparent substrate 410, RF transmissions from the first antenna 420 may be curtailed and the RF signals sent to the second antenna 450 for transmission.
The process 600 begins at block 610, where a transparent substrate through which an image may be displayed is provided. The transparent substrate may include a surface having a display region and a non-display region that surrounds at least a portion of a perimeter of the display region. In some implementations, the transparent substrate may be made of glass, plastic, or other substantially transparent material. For example, the transparent substrate may be one of an antenna panel, a cover plate, a cover glass, a touch panel, a front light, a display glass, a backplane, a back plate, or a backlight. In some implementations, the transparent substrate may have a thickness between about 10 μm and about 700 μm. In some implementations, the transparent substrate may have a thickness between about 300 μm and 500 μm.
The process 600 continues at block 620, where a first antenna is formed in the display region of the transparent substrate. The first antenna may be transparent or non-transparent. For example, the first antenna may be transparent and positioned in a display region of the transparent substrate. In another example, the first antenna may be transparent or non-transparent and positioned in a non-display region of the transparent substrate. In some implementations, the first antenna may be made of a transparent conductive oxide, such as ITO. In some implementations, the first antenna may include a transparent material and electrically reinforced with narrow, transparent or non-transparent traces. In some implementations, the first antenna may include a grid of narrow, transparent or non-transparent traces. The first antenna may include, for example, a patch antenna, a dipole antenna, a PIFA, a slot antenna, a planar antenna, a meander-line antenna, a fractal antenna, a multi-band antenna, an ultra-wide band antenna, a circularly polarized antenna, a duplex antenna, a cancellation antenna, a beam-forming antenna, a steerable antenna, or an adaptive antenna.
In some implementations, the first antenna may be part of multiple antennas on the transparent substrate. The first antenna may have at least one of spatial diversity, frequency diversity, temporal diversity, polarization diversity, and other diversity type with the other antennas on the transparent substrate.
In some implementations, the first antenna may be augmented or electrically reinforced with electrically conductive traces formed on the first antenna. The electrically conductive traces may be made of aluminum, an aluminum alloy, aluminum-silicon, copper, chromium, molybdenum, molybdenum-chromium, silver, or a combination thereof. The electrically conductive traces may be made of non-transparent material while not substantially occluding the image of the display, and/or the electrically conductive traces may be formed in the non-display region of the transparent substrate to avoid interference with the image of the display.
The process 600 continues at block 630, where a second antenna is cooperatively coupled with the first antenna, and the second antenna is either transparent or non-transparent. In some implementations, a PCB may be provided with the display device and configured to be in electrical communication with the first antenna, where the second antenna is connected or otherwise disposed on the PCB. In some implementations, a display element may be configured between the PCB and the transparent substrate.
In some implementations, the second antenna may be a PCB antenna, a non-transparent metal-film patch antenna, a low-temperature co-fired ceramic (LTCC) antenna, a wire antenna, or another antenna type discussed earlier herein. In some implementations, the second antenna may be transparent or non-transparent, and formed in a non-display region of the transparent substrate. In some implementations, the second antenna may be transparent and formed in the display region of the transparent substrate along with the first antenna. The first antenna and the second antenna may be part of a MIMO system to increase channel capacity. The first antenna and the second antenna may exhibit antenna diversity, including but not limited to at least one of spatial diversity, temporal diversity, frequency diversity, and polarization diversity.
In some implementations, the second antenna may be configured to operate in a different mode from the first antenna. For example, the second antenna may be configured to transmit wireless signals while the first antenna may be configured to receive wireless signals. In some implementations, an RF switch or weighting coefficients that serve as an RF switch may be provided or generated to differentiate and selectively switch between the operating modes.
As described above, one example of a suitable display device to which the described implementations may apply, is a reflective display device such as an IMOD display device.
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 (A).
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
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 one or more antennas 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), 1xEV-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.
