Patent Publication Number: US-2023158750-A1

Title: Systems and methods of control instructions generation and interpretation in additive manufacturing of electronic components

Description:
BACKGROUND 
     The field of the disclosure relates to manufacturing of electronic components, and more particularly, to additive manufacturing of electronic components. 
     Different techniques are known to manufacture electronic components such as resistors or voltage dividers by applying a non-insulating, electrically resistive film or foil material onto an insulating substrate. Typical methods are sputtering (thin film) or screen and stencil printing (thick film). 
     Known systems and methods of manufacturing electronic components are disadvantaged in some aspects and improvements are desired. 
     BRIEF DESCRIPTION 
     In one aspect, a system of additive manufacturing of an electronic component is provided. The system includes a deposition control computing device, the deposition control computing device including at least one processor in communication with at least one memory device. The at least one processor is programmed to generate control instructions of additive manufacturing of the electronic component, interpret the control instructions into controls of the system, and output the controls. 
     In another aspect, a system of additive manufacturing of an electronic component is provided. The system includes a deposition control computing device, the deposition control computing device including at least one processor in communication with at least one memory device. The at least one processor is programmed to receive, in a user interface, user inputs, generate control instructions of additive manufacturing of the electronic component based on the user inputs, and output the control instructions. 
     In one more aspect, a system of additive manufacturing of an electronic component is provided. The system includes a deposition control computing device, the deposition control computing device including at least one processor in communication with at least one memory device. The at least one processor is programmed to interpret control instructions of manufacturing the electronic component into controls of the system by interpreting the control instructions into fundamental actions in the system and output the controls. 
    
    
     
       DRAWINGS 
       Non-limiting and non-exhaustive embodiments are described with reference to the following Figures., wherein like reference numerals refer to like parts throughout the various drawings unless otherwise specified. 
         FIG.  1 A  is a schematic diagram of an exemplary system of additive manufacturing. 
         FIG.  1 B  is a schematic diagram of an exemplary disposition assembly of the system shown in in  FIG.  1 A . 
         FIG.  1 C  is a schematic diagram of a deposition control computing device of the deposition assembly shown in  FIG.  1 B . 
         FIG.  2 A  is a flow chart of an exemplary control instruction generator of the deposition control computing device shown in  FIG.  1 C . 
         FIG.  2 B  is an exemplary user interface to receive user inputs for generating control instructions. 
         FIG.  3    is a block diagram of an exemplary user interface of an exemplary control instruction interpreter of the deposition control computing device shown in  FIG.  1 C . 
         FIG.  4    shows exemplary voltage dividers manufactured using systems and methods shown in  FIGS.  1 A- 3   . 
         FIG.  5    is a schematic diagram of a user computing device. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure includes systems and methods of additive manufacturing of electronic components such as resistors or voltage dividers. Method aspects will be in part apparent and in part explicitly discussed in the following description. 
     In manufacturing electronic components such as resistors or voltage dividers, the process includes depositing a film onto a substrate, baking the deposition with the substrate in a high temperature furnace such as over 500° C., and trimming the resistive path to fine-tune the electronic component. During deposition, a non-insulating, electrically resistive film or foil material, such as metal film or metal foil, e.g., nickel chromium, cermet film, e.g., tantalum nitride, ruthenium dioxide, bismuth ruthenate, carbon film, or a film of composite material based on a mixture of glass and cermet is deposited onto an insulating or dielectric substrate. The insulating substrate may be ceramic, silicon, glass or other synthetic material. In addition, highly conductive structures with considerable lower resistivity than the film material of the resistors are deposited on the substrate as well. The highly conductive structures are intended to be used as contacting terminals, and they are placed on the substrate in such a way that the resistive film material of the resistors overlaps partly with them. 
     Film material may be applied to the substrate by known methods such as sputtering or screen printing. Sputtering is not suitable for manufacturing resistors having a high resistance value (e.g., 20 M ohm or greater), voltage dividers having a high voltage ratio, or components in high voltage sensors. Screen printing therefore is typically used. Screen printing allows for reasonably high throughput on complex circuit shapes such as those in non-inductive high voltage resistors and other integrated circuits. Screen printing process, however, is inflexible. Screen printing requires a screen or mask to be generated. For low volume parts and circuit designs, it is prohibitively costly to operate a manufacturing line for screen printing for small orders and custom designs. Current suppliers of resistors for high voltage and high power devices have long lead times, such as weeks or even months for standard designs and longer for custom orders. Some custom and complex resistors having features such as voltage cushions, integrated voltage dividers, or non-typical resistance values have even longer lead times. 
     In contrast, an additive manufacturing method offers a high degree of design flexibility whiles still providing relatively high throughput. With additive methods, increased complexity does not require an increase in production cost. Rather than designing screens, the systems and methods disclosed herein provide automatic and flexible generation of control instructions and control of the additive manufacturing of electronic components. Systems and methods described herein provide a low cost printer with multiple movement stages, motors and control system that drastically reduces lead time to a time frame for example less than three days, allows for rapid prototyping of new designs, increases automation, and reduces the overall part count in printing integrated circuits. 
     Compared to screen-printing, one more advantage of additive manufacturing is that deposition patterns in additive manufacturing are not limited by the screen. In screen-printing, because a screen is required, screen-printing cannot print a pattern having a complete loop that encompasses a circumference of a three-dimensional (3D) substrate such as a cylindrical substrate, limiting designs of electronic components. 
     In conventional additive manufacturing of an object, multiple layers are used, each layer having a thickness of the level of at least several micrometers, with final part having millimeters to meters in at least one dimension. Further, typically the control codes of manufacturing the object requires input of a finalized 3D design of the object and the generation process is not modular, where similar or same features are designed separately repeatedly. 
     In contrast, in additive manufacturing of electronic components, especially high voltage electronic components, a single layer is typically used and the thickness of each layer is in the order of μm. Systems and methods described herein allow a user to provide properties of an electronic component and generate a deposition design of the electronic component that has the properties, instead of requiring a final 3D design of the electronic component. In addition, systems and methods described herein use a modular design, where similar or same features are design once and then adjusted based on parameters or properties of the electronic components, thereby increasing the efficiency of the process. 
     Furthermore, systems and methods described herein include generating instructions that instruct robot(s) to operate the printer to improve resistor placement reproducibility between different operators, different manufacturing sites, and resistor substrates originating from different suppliers. 
     Compared to conventional manufacturing of an electrical component, systems and methods described herein are advantageous in manufacturing high voltage electrical components, such as high voltage dividers. In conventional manufacturing of a voltage divider, resistors of the divider and their connections are separately designed and manufactured. Systems and methods described herein provide design flexibility, save space for electrical components, and provide uniform form factors for electrical components. For example, resistors and their connections are included one deposition design on one substrate. 
     Systems and methods described herein provide rapid prototyping and custom circuit designs, where deposition patterns are quickly generated based on user inputs. Creating a new drawing for each pattern and going through various iterations on the design is time consuming for an engineer. Systems and methods described herein automates the design process and converts the design into machine code for the actuator controllers for fast prototyping. Robotic integration offers integration of the technology across multiple sites with or without personnel training in the field of resistor handling throughout the printing process, offering reduction in sample-to-sample and site-to-site variability, as well as streamlined resources available on a 24/7 basis. 
       FIG.  1 A- 1 C  are a schematic diagram of an exemplary system  120  of additive manufacturing of an electronic component ( FIG.  1 A ), a schematic diagram of an exemplary deposition assembly or printer  150  of system  120  ( FIG.  1 B ), and a schematic diagram of an exemplary deposition control computing device  151  used to control deposition assembly  150  ( FIG.  1 C ). The electronic component may be a high voltage electronic component such as a high voltage divider. The voltage of the electronic component may be 3.6 kV or above. Alternatively, the resistance ratio of the voltage divider is greater than 1000:1, or even greater than 10,000:1. The electronic component may be a resistor or a voltage divider, which may be used in a voltage sensor. In the exemplary embodiment, the system  120  includes a deposition assembly  150  configured to deposit an additive material  126  onto a substrate  110  ( FIG.  1 B ), and a furnace  152  used to bake the printed components. System  120  may include a trimming assembly  154 . The systems and methods described herein, however, do not require a trimming assembly  154 . 
     Additive manufacturing is applied to a substrate  110 . For example, substrate  110  is configured to form a voltage divider for use in a high voltage sensor. Substrate  110  is generally a dielectric substrate, e.g. a ceramic material or plastic, that does not conduct electricity. Substrate  110  includes a surface  112  that is configured to receive an additive material, such as a conductive material or a resistive paste that is applied using additive manufacturing. In some embodiments, surface  112  is non-planar. For example, substrate  110  is generally cylindrical in shape. 
     In the exemplary embodiment, deposition assembly  150  of system  120  includes a dispenser  122  and an actuator  144 . A dispenser may also be referred to as a dispensing needle. Dispenser  122  may be a pneumatic dispenser, a syringe pump dispenser, or other dispensing devises configured to dispense a material having a high viscosity, e.g., greater than 1000 centipoise. The dispenser includes a dispensing tip  124 . The size of tip  124  may be in the range of approximately 100-2000 μm, or 250-1000 μm. Tip  124  of dispenser  122  is moved along surface  112  of substrate  110  to apply an additive material  126  to surface  112 . 
     In the exemplary embodiment, deposition assembly  150  further includes a chuck  158 , a motor  160 , stages  162 , and a deposition control computing device  151 . Chuck  158  may be a rotary chuck that holds substrate  110  and rotates substrate  110  during printing. Motor  160  provides movement of chuck and stages. Motor  160  may be a motor assembly that includes a plurality of motors. Stages  162  may be three linear moveable stages along three axes x, y, and z. Dispenser  122  is coupled to stages  162  such that positions and movements of dispenser  122  is adjusted or controlled. Deposition control computing device  151  is in communication with chuck, motor, stages, and a controller  138  of actuator  144  and controls operation of deposition assembly  150 . Deposition control computing device  151  may be a user computing device, a processor-based microcontroller, or a combination of both. 
     Deposition assembly  150  may further include controller  138  in communication with actuator  144 . In some embodiments, controller  138  includes a processor-based microcontroller including a processor  146  and a memory device  148  wherein executable instructions, commands, and control algorithms, as well as other data and information needed to satisfactorily operate system  120 , are stored. Memory  148  includes instructions that when executed by processor  146  enable controller  138  to control actuator  144 , which in turn controls the movement and positions of Dispenser  122 . In some embodiments, memory device  148  may be, for example, a random access memory (RAM), and other forms of memory used in conjunction with RAM memory, including but not limited to flash memory (FLASH), programmable read only memory (PROM), and electronically erasable programmable read only memory (EEPROM). 
     As used herein, the term “processor-based” microcontroller shall refer not only to controller devices including a processor or microprocessor as shown, but also to other equivalent elements such as microcomputers, programmable logic controllers, reduced instruction set circuits (RISC), application specific integrated circuits and other programmable circuits, logic circuits, equivalents thereof, and any other circuit or processor capable of executing the functions described below. The processor-based devices listed above are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of the term “processor-based.” 
     In the exemplary embodiment, deposition assembly  150  is controlled by deposition control computing device  151 . Deposition control computing device  151  includes a control instruction generator  164  configured to convert a circuit design into control codes or instructions and a control instruction interpreter  166  configured to interpret control instructions into controls of deposition assembly  150 . Control instructions may be in G-Code, which is a language used to describe how a machine will move to accomplish a given task, using numerical control of machining tools such as additive printers. In some embodiments, control instructions are drawings of a deposition design for manufacturing the electronic component. The controls may be instructions downloaded or control signals transmitted to controller  138 . Deposition control computing device  151  may be two separate computing devices with control instruction generator  164  in one computing device and control instruction interpreter  166  in another computing device. Alternatively, control instruction generator  164  and control instruction interpreter  166  are in the same computing device. 
       FIGS.  2 A and  2 B  show control instruction generator  164 .  FIG.  2 A  is a flow chart of generating control instructions implemented in control instruction generator  164 .  FIG.  2 B  is an exemplary user interface  202  of control instruction generator  164 . 
     In the exemplary embodiment, control instruction generator  164  provides automated path generation for designing resistor paths from user inputs. Control instruction generator  164  is configured to take user inputs on desired device parameters such as, but not limited to, a voltage rating, power rating, primary side resistance value, and voltage divider ratio. The inputs set the parameters of the deposition design to be physically realized by deposition assembly  150 . In control instruction generator  164 , physical models and preset general path structures (e.g. non-inductive paths) are used to generate a printing path defined by G code commands readable by a microcontroller. Physical modes may be based on the physical or empirical relations of physical and electronical properties with geometrical designs of the electronic components. In some embodiments, a machine learning model or a combination of a machine learning model and a physical model may be used in designing deposition patterns. Control instruction generator  164  may also generate spiral and/or non-inductive patterns. Resistive path designs using systems and methods described herein leverage the flexibility of additive manufacturing. 
     In the exemplary embodiment, inputs may include substrate geometry, ink parameters (e.g., viscosity, solvent content, and resistivity of the ink), printing parameters (e.g., line width and printing speed), device parameters or parameters of the electronic component (e.g., axial length, resistance, resistance ratio of a voltage divider, dimensions of a contact block, a voltage rating, a power rating, or a primary side resistance value), application selections (e.g., voltage divider or resistor, whether to include a voltage cushion, and the type of pattern), electrical parameters (e.g., voltage and dielectric material), and any combination thereof. Control instruction interpreter is configured to calculate parameters based on the inputs  204  to provide calculated parameters  206  such as electrical parameters (e.g., line spacing), printing parameters (e.g., path length, number of lines, and track), contact block design (e.g., number of lines), and any combination thereof. Based on the inputs  204  and calculated parameters  206 , control instruction generator  164  provides printer-readable codes such as G-Codes. In some embodiments, control instruction generator  164  is configured to receive a technical drawing of circuit designs, such as a CAD drawing or a circuit diagram, as inputs and convert the technical drawings into modular features, G-codes, and/or or deposition designs, thereby obviating the need of manually inputting properties of the electrical component. In one embodiment, control instruction generator is configured to output a deposition design corresponding to the circuit design. In another embodiment, each pattern includes fundamental actions adapted based on input parameters. In one example, part of the scripts are written in Visual Basic® that draws input information from a spreadsheet. The output control code may be in G-Code. The output G-Code is exported to a text file that may be read in by control instruction interpreter  166 . In one example, control instruction generator  164  is configured to take user inputs on properties of a circuit such as resistance, inductance, and impedance, and generate G-Codes for a deposition design that matches the input properties. Control instruction generator  164  may output calculated features or parameters  206  in user interface  202  such that the user may examine the design. 
     In the exemplary embodiment, control instruction generator  164  includes a set of scripts that translate user inputs  204  ( FIG.  2 B ) such as ink and substrate information, voltage rating, part size, resistance value, ratios between resistances into modular commands that provide spatial directions for control instruction interpreter  166 . Modules are for particular types of patterns, and specific features of the pattern are modified by user inputs. For example, modules may include contact areas for electrical terminals, high aspect ratio traces for high resistance sections, serpentine paths for non-inductive resistors, trimming such as laser trimming tuning, and tapered paths for impulse cushioning. If a user inputs include impulse cushioning, the inputs are used in the module of tapered paths for impulse cushioning. In another example, the modules include variable parameters such as area, length, or the number of repeated features. This list is not comprehensive. New features may be added in by creating new modules. 
       FIG.  3    is a block diagram of an exemplary interface  203  of control instruction interpreter  166 , which provides controls of a microcontroller and deposition assembly  150 . In the exemplary embodiment, top left of interface  203  shows connection status to hardware. Top right of interface  203  shows a preview of the G-Code text file that is uploaded to deposition assembly  150 . Bottom left of interface  203  provides input for a command line, which is direct interfacing between the user and deposition assembly  150 . Control instruction interpreter  166  reads in a text file with G-Code commands and convert G-Codes to controls of system  120 , such as control signals of a series of actuators  144 . Control instruction interpreter  166  may be personal computer (PC) software. In some embodiments, the control instruction interpreter  166  is configured to read in drawing files of deposition patterns or designs and interpret the drawings into control signals of system  120 . The actuators may be linear micro-stepped stages, a micro-stepped rotational stage, liquid dispensing devices, and piezoelectric linear stages. This list is not exhaustive, and other actuators may be added to the printer hardware under the same control schema. The controls are transmitted to microcontroller  138 . Firmware of controller  138  co-ordinates movement speed of various actuator components to ensure a constant movement speed of the dispensing head of deposition assembly  150 . Control instruction interpreter  166  achieves those functions by interpreting the incoming commands and translating the commands into corresponding electrical signals or control signals that the motor drivers need for simultaneous, multi-axis movement. The commands may be broken down into fundamental actions that act as the building blocks of every pattern. Fundamental actions include but are not limited to linear movements, clockwise/counter-clockwise arcing, and dispensing/non-dispensing movements. The firmware of controller  138  and/or control instruction interpreter  166  may take in parameters of the geometry of the starting substrate and properties of the dispensing fluid and adapt the fundamental commands accordingly. Control instruction interpreter  166  is also configured to receive direct input from the printer user to monitor print conditions, clear memory, and other functions (see  FIG.  3   ). Control instruction interpreter  166  may be modified to include additional features such as changing movement speed of the print head as defined by the user. 
     In some embodiments, deposition control computing device  151  is configured to automate the deposition. For example, deposition control computing device  151  is configured to remove the need of manual installation, removal, and alignment of the resistor rod or substrate  110  in the printer chuck  158 . In this embodiment, software for robotic control is included in addition to the software described above. The functions of the software include picking and installing a new resistor rod into a chuck-coupled robotic arm, moving the robotic arm to the correct radial location such that the rod is at the desired needle position, moving the robotic arm to the desired axial position of the printing start, providing rotational and axial movement of the chuck with robotic arm as per G-Code described above, placing the printed resistor into a drying oven and releasing the printed resistor from the chuck. 
     In the exemplary embodiment, two separate interfaces are used for control instruction generator  164  for the circuit generation ( FIG.  2 B ) and control instruction interpreter  166  for the controls ( FIG.  3   ). In one example, the PC interface uses a C# Windows Forms Designer GUI for input, and the generation tool uses Active X controls within the input spreadsheet. In some embodiments, the circuit design and controller interfaces are integrated as one interface. 
       FIG.  4    shows voltage dividers  402  manufactured using systems and methods described herein. Printed resistive voltage dividers  402  have a high aspect ratio primary resistive path, and a low aspect ratio secondary path. Line widths (i.e. print resolution) of 300-800 microns have been generated, though larger line widths are clearly possible. Deposition assembly  150  has generated prints of resistors with resistance values as high as 50 MOhm, and higher resistances up to at least 5 GOhms are feasible. Printed path lengths may be at 1.6 meters with an aspect ratio of as high as 4000:1. Additionally, overlapping printed paths have been generated to create large printed areas with low aspect ratios. 
     Deposition control computing device  151  described herein may be any suitable user computing device  800  and software implemented therein.  FIG.  5    is a block diagram of an exemplary computing device  800 . In the exemplary embodiment, the computing device  800  includes a user interface  804  that receives at least one input from a user. The user interface  804  may include a keyboard  806  that enables the user to input pertinent information. The user interface  804  may also include, for example, a pointing device, a mouse, a stylus, a touch sensitive panel (e.g., a touch pad and a touch screen), a gyroscope, an accelerometer, a position detector, and/or an audio input interface (e.g., including a microphone). 
     Moreover, in the exemplary embodiment, computing device  800  includes a presentation interface  817  that presents information, such as input events and/or validation results, to the user. The presentation interface  817  may also include a display adapter  808  that is coupled to at least one display device  810 . More specifically, in the exemplary embodiment, the display device  810  may be a visual display device, such as a cathode ray tube (CRT), a liquid crystal display (LCD), a light-emitting diode (LED) display, and/or an “electronic ink” display. Alternatively, the presentation interface  817  may include an audio output device (e.g., an audio adapter and/or a speaker) and/or a printer. 
     The computing device  800  also includes a processor  814  and a memory device  818 . The processor  814  is coupled to the user interface  804 , the presentation interface  817 , and the memory device  818  via a system bus  820 . In the exemplary embodiment, the processor  814  communicates with the user, such as by prompting the user via the presentation interface  817  and/or by receiving user inputs via the user interface  804 . The term “processor” refers generally to any programmable system including systems and microcontrollers, reduced instruction set computers (RISC), complex instruction set computers (CISC), application specific integrated circuits (ASIC), programmable logic circuits (PLC), and any other circuit or processor capable of executing the functions described herein. The above examples are exemplary only, and thus are not intended to limit in any way the definition and/or meaning of the term “processor.” 
     In the exemplary embodiment, the memory device  818  includes one or more devices that enable information, such as executable instructions and/or other data, to be stored and retrieved. Moreover, the memory device  818  includes one or more computer readable media, such as, without limitation, dynamic random access memory (DRAM), static random access memory (SRAM), a solid state disk, and/or a hard disk. In the exemplary embodiment, the memory device  818  stores, without limitation, application source code, application object code, configuration data, additional input events, application states, assertion statements, validation results, and/or any other type of data. The computing device  800 , in the exemplary embodiment, may also include a communication interface  830  that is coupled to the processor  814  via the system bus  820 . Moreover, the communication interface  830  is communicatively coupled to data acquisition devices. 
     In the exemplary embodiment, the processor  814  may be programmed by encoding an operation using one or more executable instructions and providing the executable instructions in the memory device  818 . In the exemplary embodiment, the processor  814  is programmed to select a plurality of measurements that are received from data acquisition devices. 
     In operation, a computer executes computer-executable instructions embodied in one or more computer-executable components stored on one or more computer-readable media to implement aspects of the invention described and/or illustrated herein. The order of execution or performance of the operations in embodiments of the invention illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments of the invention may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the invention. 
     As used herein, the terms “processor” and “computer,” and related terms, e.g., “processing device,” “computing device,” and “controller” are not limited to just those integrated circuits referred to in the art as a computer, but broadly refers to a microcontroller, a microcomputer, an analog computer, a programmable logic controller (PLC), an application specific integrated circuit (ASIC), and other programmable circuits, and these terms are used interchangeably herein. In the embodiments described herein, “memory” may include, but is not limited to, a computer-readable medium, such as a random-access memory (RAM), a computer-readable non-volatile medium, such as a flash memory. Alternatively, a floppy disk, a compact disc—read only memory (CD-ROM), a magneto-optical disk (MOD), and/or a digital versatile disc (DVD) may also be used. Also, in the embodiments described herein, additional input channels may be, but are not limited to, computer peripherals associated with an operator interface such as a touchscreen, a mouse, and a keyboard. Alternatively, other computer peripherals may also be used that may include, for example, but not be limited to, a scanner. Furthermore, in the example embodiment, additional output channels may include, but not be limited to, an operator interface monitor or heads-up display. Some embodiments involve the use of one or more electronic or computing devices. Such devices typically include a processor, processing device, or controller, such as a general purpose central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, a reduced instruction set computer (RISC) processor, an ASIC, a programmable logic controller (PLC), a field programmable gate array (FPGA), a digital signal processing (DSP) device, and/or any other circuit or processing device capable of executing the functions described herein. The methods described herein may be encoded as executable instructions embodied in a computer readable medium, including, without limitation, a storage device and/or a memory device. Such instructions, when executed by a processing device, cause the processing device to perform at least a portion of the methods described herein. The above examples are not intended to limit in any way the definition and/or meaning of the term processor and processing device. 
     At least one technical effect of the systems and methods described herein includes (a) additive manufacturing of high-voltage electronic components; (b) generating circuit designs based on user inputs; (c) generating deposition designs based on properties of the electronic component, rather than a finalized design of the electronic component; and (d) modular design of features. 
     Exemplary embodiments of systems and methods of additive manufacturing of electronic components are described above in detail. The systems and methods are not limited to the specific embodiments described herein but, rather, components of the systems and/or operations of the methods may be utilized independently and separately from other components and/or operations described herein. Further, the described components and/or operations may also be defined in, or used in combination with, other systems, methods, and/or devices, and are not limited to practice with only the systems described herein. 
     Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.