Abstract:
A method and apparatus for tracking coarse and fine motions associated with an electronic input device is disclosed. The electronic input device can have both an inertial sensor and a touch sensor. The method includes receiving inputs from an inertial sensor and a touch sensor, and dynamically adjusting a velocity estimate of the electronic input device based on weighting or predetermined thresholds of the inputs to maximize a tracking range of the input device.

Description:
FIELD OF THE INVENTION 
     This disclosure relates to electronic input devices and more particularly to electronic input devices having both inertial sensors and touch sensors. 
     BACKGROUND OF THE INVENTION 
     Conventional input devices, such as computer mice, typically employ optical sensors, track wheels or track balls to control the motion of a cursor or other navigational object on a computer display screen. Other types of input devices that measure a force imparted onto the input device typically incorporate one or more accelerometers for sensing acceleration forces exerted on the input device as it is moved by a user. A velocity of the electronic input device may be calculated and estimated by integrating the measured acceleration over time, and a position estimate of the input device may be calculated by integrating its velocity over time. In this way, motion of an accelerometer-based input device may be translated to motion of a cursor or other navigational object on a computer display screen. 
     Touch-sensitive panels can also be used as an input device to control the motion of a cursor or other navigational object on a computer display screen. One common type of touch-sensitive panel is a touch pad. In general, touch-sensitive panels can detect one or more touch contacts on the surface of the touch-sensitive panel and generate signals indicative of the touch contacts. A computer can then control a cursor or other navigational object based on the detected touch contacts. 
     Various problems are associated with conventional input devices. For example, most, if not all, conventional input devices are inadequate in tracking both large and fine motions. For example, inertial sensing-based input devices typically track large ranges of motion well (e.g., moving a cursor across the length of a display screen), but not fine ranges of motions. In contrast, touch-sensitive pads typically track fine ranges of motions well, but not large ranges of motion. For example, moving a cursor from one end of the display screen to the other end may require a user to swipe his or her finger across a touch pad multiple times before the cursor moves to the other end of the display screen. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention are directed to input devices using both inertial sensors and touch sensors. An exemplary input device has a motion sensing element capable of estimating a position of the input device based on a force applied to the input device. The motion sensing element can be used to track large ranges of motion. The input device can also include a touch sensitive surface operable to detect touches on the touch sensitive surface. The touch sensitive surface can be used to track relatively smaller ranges of motion. 
     In accordance with some embodiments, a method for using inertial inputs and touch inputs of an electronic input device can include receiving a motion input from a motion sensor, and calculating a first estimated motion based on the motion input. The method can further include receiving a touch input from a touch sensor, and calculating a second estimated motion based on the touch input. The method can further include outputting the first estimated motion if the first estimated motion exceeds a first threshold, and outputting the second estimated motion if the second estimated motion exceeds a second threshold. 
     In accordance with various embodiments, an electronic input device can have a motion sensing element operable to measure a motion of the electronic input device to obtain a motion input, and a touch sensing element operable to measure a touch motion on the electronic input device to obtain a touch input. The electronic input device can also include a processing element operable to calculate a first estimated motion based on the motion input and calculate a second estimated motion based on the touch input. The processing element can also operate to provide the first estimated motion as an output if the first estimated motion is greater than a first threshold, and provide the second estimated motion as an output, if the second estimated motion is greater than a second threshold. The electronic input device can also have an external interface operable to send the output to a receiving device. 
     In accordance with various embodiments, a computer-readable medium can have instructions for receiving a motion input from a motion sensor, and calculating a first estimated motion based on the motion input. The instructions can further include receiving a touch input from a touch sensor, and calculating a second estimated motion based on the touch input. The instructions can provide for outputting the first estimated motion estimate if the first estimated motion is greater than a first threshold, and outputting the second estimated motion, if the second estimated motion is greater than a second threshold. 
     In accordance with some embodiments, method for using inertial inputs and touch inputs of an electronic input device includes receiving a motion input from a motion sensor, and calculating a first estimated motion based on the motion input. The method receives a touch input from a touch sensor, and calculates a second estimated motion based on the touch input. The method obtains a first weight and a second weight, and calculates a motion output signal based on the first and the second weights, and the first and the second motion inputs. In this manner, the motion output signal can be calculated by the relationship V=Wa*Va+Wt*Vt, where V is the motion output signal, Wa and Wt are the respective weighting factors of the velocity Va and Vt, Va (first estimated motion) is the velocity output signal derived from the accelerometer output signal, and Vt (second estimated motion) is the velocity output signal derived from the touch sensor output signal device. 
     Various embodiments relate to an electronic input device having a motion sensing element operable to measure a motion of the electronic input device, and a touch sensing element operable to detect a touch motion on the electronic input device. The electronic input device can also include a processing element operable to calculate a first estimated motion based on a motion input, calculate a second estimated motion based on a touch input, and calculate an output based on a first weight and a second weight, and the first and the second motion inputs. In this manner, the output can be calculated by the relationship V=Wa*Va+Wt*Vt, where V is the motion output signal, Wa and Wt are the respective weighting factors of the velocity Va and Vt, Va (first estimated motion) is the velocity output signal derived from the accelerometer output signal, and Vt (second estimated motion) is the velocity output signal derived from the touch sensor output signal device. The electronic input device can also have an external interface operable to send the output to an external device. 
     Further embodiments relate to computer-readable medium embodying instructions for receiving a motion input from a motion sensor, and calculating a first estimated motion based on the motion input. The instructions can also include receiving a touch input from a touch sensor, and calculating a second estimated motion based on the touch input. In additional, the instructions can include obtaining a first weight and a second weight, and calculating a motion output signal based on the first and the second weights, and the first and the second motion inputs. In this manner, the motion output can be calculated by the relationship V=Wa*Va+Wt*Vt, where V is the motion output signal, Wa and Wt are the respective weighting factors of the velocity Va and Vt, Va (first estimated motion) is the velocity output signal derived from the accelerometer output signal, and Vt (second estimated motion) is the velocity output signal derived from the touch sensor output signal device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings are provided for purposes of illustration only and merely depict exemplary embodiments of the disclosure. These drawings are provided to facilitate the reader&#39;s understanding of the disclosure and should not be considered limiting of the breadth, scope, or applicability of the disclosure. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale. 
         FIG. 1  illustrates a typical environment in which an input device may be used according to various embodiments of the present invention. 
         FIG. 2  is a block diagram of a modular arrangement of an input device according to various embodiments of the present invention. 
         FIG. 3  is a flow diagram of a hybrid inertial and touch sensing process for an electronic input device in accordance with various embodiments of the invention. 
         FIG. 4  is a flow diagram of another hybrid inertial and touch sensing process for an electronic input device process in accordance with various embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following description of preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which it is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
     Embodiments of the present invention are directed toward electronic input devices having both inertial sensors and touch-sensitive panels (e.g., touch pads). Embodiments of the invention are described herein in the context of one practical application, namely, receiving cursor control commands from an input device. Embodiments of the invention, however, are not limited to such applications, and the methods described herein may also be utilized in other applications such as game controllers. As would be apparent to one of ordinary skill in the art after reading this description, these are merely examples and the embodiments of the invention are not limited to operating in accordance with these examples. 
     As used herein, the term “application” includes without limitation any unit of executable software that implements a specific functionality or theme. The unit of executable software may run in a predetermined environment; for example, a downloadable Java Xlet™ which runs within the JavaTV™ environment. 
     As used herein, the terms “receiving device” and “receiver” include without limitation video game consoles, set-top boxes, televisions, personal computers (whether desktop, laptop, or otherwise), digital video recorders, communications equipment, terminals, mobile devices, and display devices. 
     As used herein, the terms “computer program” and “software” include without limitation any sequence of human or machine cognizable steps that are adapted to be processed by a computer. Such may be rendered in any programming language or environment including, for example, C/C++, Fortran, COBOL, PASCAL, Perl, Prolog, Python, Matlab, assembly language, scripting languages, markup languages (e.g., HTML, SGML, XML, VoXML), functional languages (e.g., APL, Erlang, Haskell, Lisp, ML, F# and Scheme), as well as object-oriented environments such as the Common Object Request Broker Architecture (CORBA), Java™ (including J2ME, Java Beans, etc.). 
     As used herein, the term “display” includes any type of device adapted to display information, including without limitation cathode ray tube displays (CRTs), liquid crystal displays (LCDs), thin film transistor displays (TFTs), digital light processor displays (DLPs), plasma displays, light emitting diodes (LEDs) or diode arrays, incandescent devices, and fluorescent devices. Display devices may also include less dynamic devices such as printers, e-ink devices, and other similar structures. 
     As used herein, the term “memory” includes any type of integrated circuit or other storage device adapted for storing digital data including, without limitation, ROM, PROM, EEPROM, DRAM, SDRAM, DDR/2 SDRAM, EDO/FPMS, RLDRAM, SRAM, “flash” memory (e.g., NAND/NOR), and PSRAM. 
     As used herein, the terms “processor,” “microprocessor,” and “digital processor” refer to all types of digital processing devices including, without limitation, digital signal processors (DSPs), reduced instruction set computers (RISC), general-purpose (CISC) processors, microprocessors, gate arrays (e.g., FPGAs), programmable logic devices (PLDs), reconfigurable compute fabrics (RCFs), array processors, and application-specific integrated circuits (ASICs). Such processors may be contained on a single unitary IC die, or distributed across multiple components. 
     As used herein, the term “interface” refers to any signal or data interface with a component or network including, without limitation, those compliant with USB (e.g., USB2), FireWire (e.g., IEEE 1394b), Ethernet (e.g., 10/100, 10/100/1000 Gigabit Ethernet, 10-Gig-E, etc.), MoCA, Serial ATA (e.g., SATA, e-SATA, SATAII), Ultra-ATA/DMA, Coaxsys (e.g., TVnet™), radio frequency tuner (e.g., in-band or OOB, cable modem, etc.), modem, WiFi (802.11a,b,g,n), WiMAX (802.16), PAN (802.15), Bluetooth, or IrDA families. 
     As used herein, the term “wireless” refers to any wireless signal, data, communication, or other interface including, without limitation, Wi-Fi, Bluetooth, 3G, HSDPA/HSUPA, TDMA, CDMA (e.g., IS-95A, WCDMA, etc.), FHSS, DSSS, GSM, PAN/802.15, WiMAX (802.16), 802.20, narrowband/FDMA, OFDM, PCS/DCS, analog cellular, CDPD, satellite systems, millimeter wave or microwave systems, acoustic, and infrared (i.e., IrDA). 
       FIG. 1  is a block diagram illustrating a typical environment in which an input device can be used according to one embodiment of the present invention. An input device  102  is initially positioned upon a surface  104  such as a desk or a tabletop. In order to generate input data, a user manipulates the input device relative to the surface  104 . 
     Note that in  FIG. 1 , the surface  104  is depicted as being flat or substantially flat; however, neither condition is necessary according to embodiments of the present invention. Also note that in some embodiments, the surface  104  need not necessarily be situated beneath the input device  102 . For example, the surface  104  may be tilted, situated above the input device  102 , inverted, or vertically oriented. Also note that in certain embodiments, multiple surfaces  104  can be utilized. 
     A receiving device (such as the depicted computer  106 ) is adapted to receive input data generated from the input device  102 . In one embodiment, the receiving device  106  comprises at least one interface adapted to receive the generated data. The input device  102  can connect to the receiving device over a wireless or a wired communication link (such as a serial bus cable or other physical connector). 
     The receiving device  106  is adapted to display a navigational object (for example, a pointer, cursor, selector box, or other such indicator) upon its display screen  108 . During operation, when the user manipulates the input device  102  relative to the surface  104 , input signals are transmitted to the receiving device  106  and the navigational object responds according to the user&#39;s input. It is understood that the receiving device  106  can be any type of computing device having a display such as an iMac™ computer or a personal computer having a separate display monitor, for example. Other types of computing devices having a display or connected to a display (e.g., by a wired or wireless communication link) for displaying navigational objects would be readily apparent to those of ordinary skill in the art. 
       FIG. 2  is a block diagram of a modular arrangement of the input device  102  according to one embodiment of the present invention. The input device  102  houses a printed circuit board  204  comprising electrical leads which enable various modules to communicate with other connected modules. 
     A power supply  206  provides a source of power to modules electrically coupled to the printed circuit board  204 . In some embodiments, power is supplied externally from one or more conductive wires, for example, as by a power cable or serial bus cable. In other embodiments, a battery may be used as a source of power. 
     A memory  212  comprises any type of module adapted to enable digital information to be stored, retained, and retrieved. Additionally, the memory  212  may comprise any combination of volatile and non-volatile storage devices, including without limitation RAM, DRAM, SRAM, ROM, and/or flash memory. Note also that the memory  212  may be organized in any number of architectural configurations, such as registers, memory buffers, main memory, mass storage, and/or removable media. In some embodiments, the memory  212  is adapted to store velocity thresholds and/or applicable ranges for each measured parameter, and code or algorithms for performing the operations described herein. In alternative embodiments, this data may be stored in a remote memory source (e.g., the hard drive of the computer  106 ), and the input device  102  merely transmits raw data to the receiving device  106  for processing by one or more processors (not shown) in the receiving device  106 . 
     One or more processors  208  are adapted to execute sequences of instructions by loading and storing data to the memory  212 . These instructions may include, for example, instructions for data conversions, formatting operations, communication instructions, and/or storage and retrieval operations. Additionally, the processors  208  may comprise any type of digital processing devices including, for example, digital signal processors, reduced instruction set computers, general-purpose processors, microprocessors, gate arrays, programmable logic devices, reconfigurable compute fabrics, array processors, and application-specific integrated circuits. Note also that the processors  208  may be contained on a single unitary IC die or distributed across multiple components. 
     An interface module  214  enables data to be transmitted and/or received via one or more communication protocols or networks. In one embodiment, data transmitted to a receiving device is first packetized and processed according to a standardized protocol. In many variants, the standardized protocol may include a plurality of network layers such that each layer provides services to the layer above it and receives services from the layer below it. The interface module  216  may accommodate any wired or wireless protocol including, without limitation, USB, FireWire, Ethernet, Gigabit Ethernet, MoCA, radio frequency tuners, modems, WiFi, Blutooth, WiMax, and/or Infrared Data Association. 
     One or more motion sensors  210  enable the input device  102  to determine velocity values during a given instant, or alternatively, over a given period of time. Various types of motion sensors such as accelerometers, gyroscopes, etc. may be incorporated as motion sensor  210 . In one embodiment, the motion sensors  210  comprise one or more accelerometers adapted to detect the current acceleration of the input device  102 . In this embodiment, velocity values are determined by logic adapted to integrate a detected acceleration quantity. In one embodiment, the motion sensor  210  includes at least one micro electromechanical system (MEMS) accelerometer. Optionally, the micro electromechanical system may comprise a dedicated microprocessor adapted to interact with one or more accelerometers that sense acceleration forces exerted on the input device  102 . 
     Input device  102  can also include one or more touch sensors  216 . In general, the touch sensors  216  can be in the form of a touch-sensitive panel or pad that can detect the location of touch events (e.g., the touching of a finger or stylus) on the surface of the panel or pad via capacitive or pressure sensors. Various types of touch-sensitive panels are described in more detail in applicants&#39; patent application Ser. No. 10/840,862, entitled “Multipoint Touchscreen,” filed May 6, 2004, which is hereby incorporated by reference in its entirety. 
       FIGS. 3 and 4  are exemplary flow diagrams for processes  300  and  400  in accordance with various embodiments of the invention. The various tasks performed in connection with processes  300  and  400  may be performed by hardware, software, firmware, or any combination thereof. It should be appreciated that these processes may include any number of additional or alternative tasks, the tasks shown in  FIGS. 3-4  need not be performed in the illustrated order, and these processes may be incorporated into a more comprehensive procedure or process having additional functionality not described in detail herein. In various embodiments, portions of processes  300  and/or  400  may be performed by elements of system  100  ( FIG. 1 ) and/or input device  102  ( FIGS. 1 and 2 ). 
     In general, process  300  can calculate an accelerometer-based velocity Va and a touch sensor-based velocity Vt and compare the accelerometer-based velocity Va and the touch sensor-based velocity Vt to respective predetermined thresholds. Based on these comparisons, process  300  can provide an input signal that can more closely reflect a user&#39;s intended input. 
     With reference to  FIG. 3 , one or more motion sensors generate one or more signals indicative of an acceleration of the input device  102  (step  302 ). The acceleration value can represent a user&#39;s motion of the input device  102  used to control a graphical object displayed on a computer screen, for example. 
     Process  300  then calculates a velocity Va of the electronic input device in step  304 . The velocity Va can be calculated by integrating the acceleration value obtained in step  302 . Of course, other ways of calculating or otherwise determining a velocity of the input device  102  can be used to determine velocity Va. 
     In step  306 , one or more touch sensors  216  generate one or more signals indicative of locations of one or more detected touches on the touch sensor  216 . From changes in locations of detected touches over time, a velocity Vt can be calculated in step  308 . For example, the touch sensor  216  can sense a first contact at position Xt 1  on a touch sensitive-surface at time t 1  and a second contact at position Xt 2  on the touch-sensitive surface at time t 2 . Velocity Vt can then be calculated using the following expression:
 
 Vt =( Xt 2− Xt 1)÷( t 2 −t 1)  (1)
 
Alternatively velocity Vt can be determined by an instantaneous velocity or an average value of velocity over a plurality of samples, for example, about 100 samples. If (t 2 −t 1 ) is the minimum unit of time in the system, in one embodiment, the velocity obtained may be an instantaneous velocity. Otherwise, it may be an average velocity during the period (t 2 −t 1 ). In such cases, the averaging operation can include a low-pass filtering operation to obtain a less noisy estimate of the average velocity.
 
     In accordance with various embodiments, steps  302  and  304  can be performed substantially concurrently with steps  306  and  308 . 
     Process  300  can then determine which sensor output (e.g., output from the motion sensor  210  or output from the touch sensors  216 ) should be used to control an associated graphical object on a display screen. 
     In this regard, process  300  can compare the velocity value Va to a first predetermined threshold in decision step  310 . If the velocity value Va exceeds the predetermined threshold, then the velocity value Va is set as the output velocity value V in step  312 . Setting the velocity output V equal to the velocity value Va translates a user&#39;s movement of the input device  102  into movement of an associated graphical object, for example, without taking into account any touches of touch sensor  216 . 
     On the other hand, if the velocity value Va does not exceed the first threshold, then the velocity value Vt can be compared to a second predetermined threshold in decision step  314 . If the velocity value Vt exceeds the second predetermined threshold, then the velocity value Vt is set as the output velocity V. Velocity Vt exceeding the second predetermined threshold can indicate, for example, a user&#39;s intention to control an associated graphical object through use of the touch pad. 
     If Va is less than the first predetermined threshold (decision step  310 ) and the velocity Vt less than the second predetermined threshold (decision step  314 ), then process  300  need not provide any output (step  318 ). This can indicate, for example, that the user has provided no indication to control a graphical object. 
     The first and second predetermined thresholds can be selected by determining when a velocity indicates a fast movement, and can vary depending upon the particular application or user preference. In one embodiment, the first and the second predetermined threshold values are each about 4 cm/sec. 
       FIG. 4  is a flow diagram of another process  400  in accordance with various embodiments. In general, process  400  can calculate output velocity V by using a waited sum of velocities Va and Vt. Velocities Va and Vt can be obtained in the same fashion as explained above in steps  302 - 308  with reference to  FIG. 3 . 
     In step  410 , process  400  can calculate or select a weighted velocity value Wa associated the velocity Va and a weighted velocity value Wt associated with velocity Vt. Process  400  can then calculate an output velocity V in step  512  using the following expression:
 
 V=Wa*Va+Wt*Vt   (2)
 
where Wa and Wt are the respective weighting factors of Va and Vt, and V is the velocity output signal of the electronic input device.
 
     In accordance with various embodiments, the weighted values Wa and Wt can each have a value ranging from 0 to 1 and can be selected using various criteria and in various ways. Some exemplary, non-limiting ways of selecting the weighted values Wa and Wt are provided below. 
     As a first example, a velocity Va that exceeds a threshold value can indicate that a user is performing a large motion with the input device  102 . As a result, an output velocity largely or completely reflecting the measurements from the motion sensors  210  can be used. So that the motion sensor  210  associated velocity Va is used, Wa can be set to a value of one or close to one, and Wt can be set to a value of zero or close to zero. In this manner, the outputted velocity V will more closely reflect a velocity derived from the motion sensors  210 . 
     As another example, a velocity Vt that exceeds a threshold value can indicate that output from the touch sensors  216  should be set as the output velocity V. In this case, Wt can be set to a value of one or close to one, and Wa can be set to a value of zero or close to zero. 
     As yet another example, values for Wa and Wt can be calculated by measuring energy values for each of the motion sensor output and touch sensor output, and setting the values for Wa and Wt in proportion to the energy values. For example, root mean square (RMS) values of Va and Vt can be calculated over a window of past samples, and normalized to a maximum value. Thus, the value of Wa can be equal to a normalized RMS of Va, and the value of Wt can be equal to a normalized RMS of Vt. 
     As yet another example, Wa and Wt can be calculated using the following expressions: 
                   Wa   =     max   ⁡     (         V   a       V   c       ,   1     )               (   3   )               Wt   =     1   -   Wa             (   4   )               
where Vc is a selected “crossover” velocity that determines a “pivot point” so to speak at which one weighting coefficient becomes greater or more significant than the other. In accordance with one embodiment, Vc can be about 4 cm/sec. For example, if Va≧Vc, then the value for Wa is set to one, and the value for Wt is zero. This can indicate that only the motion sensor output should be used to control movement of a cursor, for example. If Va&lt;Vc, then the value for Wa is less than one, and the value for Wt is greater than zero. This can indicate that the touch sensor output is to be used to control or affect cursor motion. It is understood that various other methods, algorithms and/or criteria for weighting may be used, as would be apparent to one skilled in the art after reading this disclosure.
 
     An additional factor to consider when measuring velocity Vt can be the pressure exerted by a finger or stylus on the touch sensors  216 . The amount of pressure on the touch sensors  216  can effect the capacitance values outputted by the touch sensors  216 , since greater pressure on the touch sensors  216  can increase proximity of a dipole charge (e.g., from the finger to the touch sensors). The change in capacitance measure can then be utilized as a factor in determining a value for weight Wt. For example, increased pressure on the touch pad or sensor can indicate that a higher weight Wt should be assigned to the velocity Vt measurement. 
     Whether to use the method of process  300  or process  400  can depend on the type of the noise expected from the sensors used in the motion sensor or accelerometer. For example, if the noise is independent of the velocity and acceleration, and is additive, a linear relationship such as that in weighted sum methods may be preferable, since an optimum weight can be controlled. However, noise may not be well defined, and the accelerometer may have clean output below a certain output threshold and very noisy output above the threshold. In such cases, the weight may be better chosen as a non-linear function of velocity for optimal estimation. Such a function can be easily determined for various applications by those of skill in the art, without undue experimentation. It is appreciated that, in one embodiment, process  300  may be a subset of process  400  where the weight values s are simply set equal to one. 
     Although the present invention has been fully described in connection with embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the present invention as defined by the appended claims. 
     Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as mean “including, without limitation” or the like; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; and adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future. Likewise, a group of items linked with the conjunction “and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as “and/or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction “or” should not be read as requiring mutual exclusivity among that group, but rather should also be read as “and/or” unless expressly stated otherwise. Furthermore, although items, elements or components of the disclosure may be described or claimed in the singular, the plural is contemplated to be within the scope thereof unless limitation to the singular is explicitly stated. The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent.