FIBER

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Chinese Patent Application No. 201210445763.8 filed on November 9, 2012 in the State Intellectual Property Office of China, the whole disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a system for processing an end surface of an optical fiber, more particularly, relates to a system for processing an end surface of an optical fiber with an electrode discharge device and a method of processing an end surface of an optical fiber.

Description of the Related Art

In prior arts, it has been proposed a surface process solution for plating an

anticorrosion and antifriction coating on a surface of a metal by a method of surface discharge process. For example, Fig.l shows an illustrative principle view of a surface process solution in prior arts based on an electrode discharge. As shown in Fig. l, a tip electrode 201 is placed to face a metal work piece 202, acted as a ground terminal, to be processed. The tip electrode 201 may perform various processes, such as plating, soldering, surface cutting and so on, on the metal work piece 202.

For example, a Chinese patent No. l 106902C discloses a surface discharge process device in which a voltage is applied between an electrode, which is made of a modification material or raw material, and a metal as a material to be processed to produce a surface discharge and form a modification layer on the surface of the metal. A plurality of electrodes electrically insulated from each other are connected to respective special power sources for supplying discharge pulses to the respective electrodes.

Fig.2 shows an illustrative principle view of splicing two optical fibers based on an electrode discharge according to an example in prior arts.

As shown in Fig.2, a pair of tip electrodes 301 and 302 are positioned opposite to each other. Two optical fibers are arranged in an electric discharge arc area between the pair of tip electrodes 301, 302 and are spliced together by an electric discharge arc produced in the electric discharge arc area. However, with such electrode configuration, it needs a higher current in the electrodes, and the electrodes consume a larger amount of power.

In the prior arts, in order to achieve an optic connection of two optical fibers with a low insertion consumption, end surfaces of the optical fibers are manually processed by multiple grinding processes in a mechanical grinding manner. During splicing the optical fibers, it needs to use a grinding machine to process the ends of the optical fibers. However, the grinding machine has a large volume and is not adapted to be mounted by a user in the field where the optical fibers are to be spliced.

SUMMARY OF THE INVENTION The present invention has been made to overcome or alleviate at least one aspect of the above mentioned disadvantages.

Accordingly, it is an object of the present invention to provide a system and a method for processing an end surface of an optical fiber, in which the end surface of the optical fiber (a surface of nonmetal material) is processed by an electric discharge arc produced between a plurality of tip electrodes and a plate-shaped electrode, therefore, the end surface of the optical fiber can be processed uniformly and flexibly.

According to an aspect of the present invention, there is provided a system for processing an end surface of an optical fiber comprising a plurality of electrode heads each including: a plate-shaped electrode having one type of polarity; and a set of tip electrodes having the other type of polarity and facing the plate-shaped electrode. The set of tip electrodes comprises a plurality of tip electrodes arranged in parallel and when discharging, an electric discharge arc area is generated between the plurality of tip electrodes and the plate-shaped electrode, to process an end of the optical fiber disposed in the electric discharge arc area.

In an exemplary embodiment according to the present invention, the plurality of tip electrodes of the set of tip electrodes comprising: a stationary reference electrode configured to be fixed in a place; at least one movable electrode configured to be movable relative to the stationary reference electrode.

In another exemplary embodiment according to the present invention, the plate-shaped electrode is configured to be movable relative to the stationary reference electrode.

In another exemplary embodiment according to the present invention, a through hole, through which the optical fiber is fed into the electric discharge arc area, is formed in the plate-shaped electrode.

In another exemplary embodiment according to the present invention, the system further comprises at least one transport unit each configured to transport one of the optical fibers into the electric discharge arc area in various directions.

In another exemplary embodiment according to the present invention, each of the transport units comprises a gripping mechanism in which a holding passage for holding the optical fiber is formed, and the holding passage has a substantially V-shaped cross section. In another exemplary embodiment according to the present invention, the system further comprises a plurality of first drivers each configured to be engaged with the gripping mechanism so as to control a translation, rotation or inclination of the optical fiber in the electric discharge arc area.

In another exemplary embodiment according to the present invention, the system further comprises a plurality of second drivers each configured to drive the respective plate-shaped electrode to move relative to the stationary reference electrode in a direction parallel to the tip electrodes.

In another exemplary embodiment according to the present invention, the system further comprises a plurality of third drivers each configured to drive the respective movable electrode to move relative to the stationary reference electrode.

In another exemplary embodiment according to the present invention, the system further comprises a plurality of image pick-up units each configured to capture images of positions of the plate-shaped electrode, the tip electrodes and the optical fiber.

In another exemplary embodiment according to the present invention, the system further comprises a computer unit configured to actuate at least one of the first, second and third drivers based on the captured images to change the position of at least one of the optical fiber, the plate-shaped electrode and the tip electrodes and a posture of the optical fiber.

In another exemplary embodiment according to the present invention, the plate-shaped electrode, the set of tip electrodes, the second driver and the third driver are integrated into the electrode head.

In another exemplary embodiment according to the present invention, the tip electrode is an asymmetric needle type electrode.

According to another aspect of the present invention, there is provided a method of processing an end surface of an optical fiber by using the above mentioned system, comprising: transporting a plurality of optical fibers into respective electric discharge arc areas; and controlling the plate-shaped electrode and the set of tip electrodes to discharge, so that an electric discharge arc is produced to process ends of the optical fibers disposed in the electric discharge arc areas.

In an exemplary embodiment according to the present invention, the method further comprises during producing the electric discharge arc, feeding a dielectric medium into the electric discharge arc areas through the through hole in the plate-shaped electrode so as to change and guide a pattern of the electric discharge arc.

In another exemplary embodiment according to the present invention, the method further comprises during producing the electric discharge arc, covering a surface of the plate-shaped electrode with a dielectric medium to change and guide a pattern of the electric discharge arc.

In the system and the method for processing the end surface of the optical fiber according to the above embodiments of the present invention, the end surface of the optical fiber is processed by discharging of the tip electrodes and the plate-shaped electrode, and the end surface of the optical fiber can be processed uniformly and flexibly, and the electrodes have a low power consumption. Furthermore, the system for processing the end surface of the optical fiber of the present invention adopts a plasma discharge device with a small volume to process the end surface of the optical fiber, therefore, the user can easily mount the plasma discharge device in the field.

Moreover, in the system and the method for processing the end surface of the optical fiber according to the present invention, the end surface of the optical fiber is automatically processed by an electric discharge arc, so that the glass surfaces of the optical fibers are melt and spliced together, eliminating tiny cracks in the end surface of the optical fiber, reducing the surface roughness of the end surface of the optical fiber, improving the fatigue strength of the end surface of the optical fiber, and increasing the service life of the optical connection.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which:

Fig.1 shows an illustrative principle view of a surface process solution in prior arts based on an electrode discharge;

Fig.2 shows an illustrative principle view of splicing two optical fibers based on an electrode discharge according to an example in prior arts;

Fig.3 is an illustrative block diagram of a system for processing an end surface of an optical fiber according to an exemplary embodiment of the present invention;

Fig.4 is an illustrative perspective view of the system for processing the end surface of the optical fiber according to the exemplary embodiment of the present invention;

Fig.5 is an illustrative perspective view of an arrangement of an electrode unit according to an exemplary embodiment of the present invention;

Fig.6 is an illustrative perspective view of a transport unit for transporting an optical fiber according to an exemplary embodiment of the present invention;

Fig.7 is an illustrative principle view showing optical fibers transported into the system for processing the end surface of the optical fiber in various manners;

Fig.8 is an illustrative view showing an optical fiber entering into an electric discharge arc area according to an exemplary embodiment of the present invention;

Fig.9 is an illustrative view showing an optical fiber entering into an electric discharge arc area according to another exemplary embodiment of the present invention; and

Fig.10 is a control flow diagram of a method for processing an end surface of an optical fiber by using the system for processing the end surface of the optical fiber of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE IVENTION

Exemplary embodiments of the present disclosure will be described hereinafter in detail with reference to the attached drawings, wherein the like reference numerals refer to the like elements. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art.

As shown in Figs.3-7, according to a general embodiment of the present invention, there is provided a system for processing a surface of a nonmetal material, for example, an end surface of an optical fiber. The system comprises a plurality of electrode heads 1. Each of the electrode heads 1 includes: a plate-shaped electrode 11 having one polarity (for example, a negative polarity); and a set of tip electrodes 12 having the other polarity (for example, a positive polarity) and facing the plate-shaped electrode 11. The set of tip electrodes 12 comprises a plurality of tip electrodes arranged in parallel. The plurality of tip electrodes and the plate-shaped electrode 11 are configured to produce an electric discharge arc area 13 between them, when discharging, to process an end of the optical fiber 50 disposed in the electric discharge arc area 13. For example, when a voltage is applied between the plate-shaped electrode 11 and the set of tip electrodes 12, an electric discharge arc is produced in an area between them to form the electric discharge arc area 13. The optical fiber 50 disposed in the electric discharge arc area 13 is locally heated and melt to eliminate burrs from the end surface and smooth the end surface, so that the end surface of the optical fiber is adapted to be spliced with another optical fiber. In this way, the conventional mechanical grinding processes on the end surface of the optical fiber prior to splicing are avoided, improving the splicing efficiency. Furthermore, during discharging, a large electric arc spot is produced on the plate-shaped electrode 11 , decreasing the current density on the plate-shaped electrode 11, and reducing the power consumption of the electrode.

Referring to Fig.5, the plurality of tip electrodes of the set of tip electrodes 12 comprise a stationary reference electrode 121 configured to be fixed in a place; and three movable electrodes 122, 123, 124 configured to be movable relative to the stationary reference electrode 121. Each of the tip electrodes 12 may be an asymmetric needle or cone type electrode. Furthermore, the plate-shaped electrode 11 is configured to be movable relative to the stationary reference electrode 121. As a result, by moving at least one of the movable electrodes 122, 123 and 124, it can change a temperature in a local region in the electric discharge arc area 13, so that the end surface of the optical fiber can be processed as necessary to satisfy a desired surface configuration and quality of the optical fiber. In the present invention, the plate-shaped electrode 11 and the set of tip electrodes 12 of the electrode head 1 constitute a plasma discharge device with a small volume for processing the end surface of the optical fiber, therefore, the user can easily mount the entire system in the field.

In a system for processing the end surface of the optical fiber according to another embodiment of the present invention, a through hole 111 is formed in the plate-shaped electrode 11. A nonmetal material, for example, the optical fiber 50, may be fed into the electric discharge arc area 13 through the through hole 111. Also, a dielectric medium may be fed into the electric discharge arc areas 13 through the through hole 111, or a surface of the plate-shaped electrode may be covered with a dielectric medium to change and guide a pattern of the electric discharge arc, for achieving a desired process on the nonmetal material.

The system for processing the end surface of the optical fiber of the present invention further comprises at least one transport unit 2 each configured to transport one of the optical fibers 50 into the electric discharge arc area 13 in various directions. In an embodiment, each of the transport units 2 comprises a gripping mechanism 21. As shown in Fig.6, a holding passage 22 for holding the optical fiber 50 is formed in the gripping mechanism 21, and the holding passage 22 has a substantially V-shaped cross section. As shown in Fig.3, the system for processing the end surface of the optical fiber of the present invention further comprises a plurality of first drivers each configured to be engaged with the gripping mechanism 21 so as to control a translation, rotation or inclination of the optical fiber 50 in the electric discharge arc area 13. The gripping mechanism 21 may be a flat plate gripper.

Figs.7-9 show illustrative principle views showing optical fibers transported into the system for processing the end surface of the optical fiber in various manners. By controlling the gripping mechanism 21, the optical fiber 50 may be transported into the electric discharge arc area 13 through the through hole 111 formed in the plate-shaped electrode 11 in a direction parallel to the tip electrodes, may be transported into the electric discharge arc area 13 through the tip electrodes in the direction parallel to the tip electrode, or may be transported into the electric discharge arc area 13 between the set of tip electrodes and the plate-shaped electrode in a direction perpendicular to the tip electrode. Alternatively, the optical fiber 50 may be transported into the electric discharge arc area 13 in an inclination manner in which an axial direction of the optical fiber 50 has an inclination angle Θ relative to the plate-shaped electrode 11. Since the optical fiber 50 can be transported into the electric discharge arc area 13 at different locations, in different directions and at different angles, it can flexibly control the position and posture of the optical fiber in the electric discharge arc area 13 and can uniformly process the end surface of the optical fiber or arrive a special configuration of the end surface of the optical fiber. In the present invention, the gripping mechanism 21 of the transport unit can flexibly transport a part of a work piece to be processed (for example, the optical fiber) into the electric discharge arc area 13 produced by the electrode head 1 in a translation, rotation or inclination manner. For example, as for the optical fiber, the gripping mechanism 21 may transport it into the electric discharge arc area 13 in a direction parallel to or perpendicular to an electric discharge arc column or at an inclination angle relative to the electric discharge arc column.

The system for processing the end surface of the optical fiber of the present invention further comprises a plurality of second drivers each configured to drive the respective plate-shaped electrode 1 1 to move away from or towards the stationary reference electrode 121 in a direction parallel to the tip electrodes 12. The system for processing the end surface of the optical fiber of the present invention further comprises a plurality of third drivers each configured to drive the respective movable electrode 122, 123 or 124 to move relative to the stationary reference electrode 121. Each of the third drivers is provided with a motor (not shown), each of the motors is electrically connected to the respective movable electrode 122,

123 and 124 so as to drive the movable electrode to move in at least one of X-axis, Y-axis and Z-axis directions of a three-dimensional coordinate system. For example, as shown in Fig.5, the movable electrode 122 may be moved in the X-axis direction, the movable electrode 123 may be moved in the X-axis and Z-axis directions, and the movable electrode

124 may be moved in the Z-axis direction. In this way, a distance between any two electrodes of the plate-shaped electrode 11 , the stationary reference electrode 121 and the movable electrodes 122, 123, 124 can be adjusted according to various requirements for processing the optical fiber 50 in the electric discharge arc area 13. Any one of the electrodes can be reset to its original position by the respective driver. Furthermore, any of the electrodes can be detached, replaced and maintained.

As shown in Fig.3, the system for processing the end surface of the optical fiber of the present invention further comprises a plurality of image pick-up units 3 each configured to capture images of positions of the plate-shaped electrode 1 1 , the tip electrodes and the optical fiber 50. Particularly, the image pick-up unit 3 comprises a camera for capturing an image, a bracket for supporting and moving the camera, a high light source for illuminating an image-capturing area and an image acquisition card for storing the image captured by the camera.

The system for processing the end surface of the optical fiber of the present invention further comprises a computer unit configured to actuate at least one of the first, second and third drivers based on the captured images to change the position of at least one of the optical fiber 50, the plate-shaped electrode 1 1 and the tip electrodes or adjust a posture of the optical fiber 50 by translating, rotating or inclining the optical fiber 50. Further, the system for processing the end surface of the optical fiber of the present invention further comprises a first controller and a second controller. The computer unit may be

communicated with the first and second controllers, so that the first controller can control the operation of the first driver via a first driving circuit, and the second controller can control the operations of the second and third drivers via a second driving circuit. The computer unit functions as a general monitoring device for monitoring the operation of the entire system in real time and can provide data communication, conversion, process, storage and control for other units and devices. In this way, the computer unit, the transport unit, the electrode head, a first controller and the image pick-up unit constitute a system for automatically processing a surface of a nonmetal material.

For example, in the image pick-up unit, the camera captures the position image of each of the electrodes and the position image of the work piece to be processed (for example, the end surface of the optical fiber); the image storage card stores the captured images, converts the captured images into digitized images and transfers the digitized image data to the computer unit; and the computer unit analyses and compares the digitized image data, determines the relative positions of the work piece to be processed and the electrodes, and outputs control signals. The control signals are transmitted to the gripping mechanism of the transport unit through serial communication to adjust the position of the gripping

mechanism relative to the electrodes, thereby adjusting the position of the work piece to be processed.

In an exemplary embodiment of the present invention, as shown in Fig.4, the plate-shaped electrode, the set of tip electrodes, the second driver and the third driver may be integrated into an electrode head 1. In addition, the second controller and the second driving circuit may be integrated into a control unit 4. The electrode head 1 is electrically connected to the control unit 4 via a positive power cable 51 , a negative power cable 52 and a communication control cable 53. In order to reduce the distributed capacitance, the positive power cable 51, the negative power cable 52 and the communication control cable 53 are flexible cables and arranged at intervals or individually from each other to improve the electric property and assembly flexibility of the electrode head 1. In this way, the electrode head 1 is separate from the control unit 4 in space, achieving a flexibility of processing the nonmetal material in the field with the external electrode head 1. In another exemplary embodiment of the present invention, the electrode head 1 and the control unit 4 may be formed into an integral piece.

The control unit 4 further comprises a panel control keys 41, a LCD (liquid crystal display) 42 and a power plug 43. The panel control keys 41 and the LCD 42 constitute a man-machine interface. By operating the panel control keys 41, control parameters of the electrodes, such as the discharge current intensity, the discharge time and so on, can be input and adjusted to control, for example, the discharge arc intensity and the discharge time produced by the electrodes with the control unit 4. Furthermore, displacement parameters of the plate-shaped electrode 11 and the movable electrodes 122, 123, 124 also can be input and adjusted by operating the panel control keys 41, so that the control unit 4 can control the first and second controllers to adjust the positions of the plate-shaped electrode 11 and the movable electrodes 122, 123, 124 in the three-dimensional space. In addition, the input parameters, the positions of the electrodes, the discharge time and the position and posture of the optical fiber 50 in the electric discharge arc area 13 can be displayed on the LCD 42.

The control unit 4 may communicate with the computer unit through serial

communication. Alternatively, the control unit 4 may be operated as an individual apparatus to convert and process the data through the panel control keys 41 thereof and a single-chip microcomputer embedded therein.

Also, the transport unit may be communicated with the computer unit through serial communication. Alternatively, the first controller of the transport unit may be operated as an individual apparatus to convert and process the data through the panel control keys 41 thereof and a single-chip microcomputer embedded therein. The control panel of the first controller may be served as the man-machine interface for monitoring the operation of the gripping mechanism 21. For example, by setting the parameters through the control panel and processing the data through the embedded single-chip microcomputer, the gripping mechanism 21 is rotated or moved in at least one direction of X-axis, Y-axis and Z-axis directions of the three-dimensional coordinate system.

Although the system for processing the end surface of the optical fiber described in the above embodiments comprises only a single electrode headl, the present invention is not limited to this. The system for processing the end surface of the optical fiber of the present invention may comprise a plurality of electrode heads arranged in an array, for example, of 2* 1, 2*2, 3*2 or 3*3, so that a plurality of optical fibers (work pieces) can be

simultaneously processed. Although it has been described that the electrode head 1 comprises one plate-shaped electrode and four tip electrodes in the above embodiments, and that the four tip electrodes may simultaneously discharge towards the plate-shaped electrode, but the present invention is not limited to this. The number of the tip electrodes is not limited to four, but may be three, five, six or more. In addition, the tip electrodes may discharge at different timings and at different pulse currents under the control of computer unit.

As an automatic control system, with the computer unit, at least one of the transport unit and the electrode unit is communicated to the computer unit through serial

communication connection.

According to an exemplary embodiment of another aspect of the present invention, there is provided a method of processing an end surface of an optical fiber by using the above mentioned system for processing the end surface of the optical fiber, comprising: transporting a plurality of optical fibers 50 into respective electric discharge arc areas 13; and controlling the plate-shaped electrode 11 and the set of tip electrodes 12 to discharge, so that an electric discharge arc is produced to process ends of the optical fibers 50 disposed in the electric discharge arc areas 13. Furthermore, during producing the electric discharge arc, feeding a dielectric medium into the electric discharge arc areas 13 through the through hole in the plate-shaped electrode so as to change and guide a pattern of the electric discharge arc. Alternatively, during producing the electric discharge arc, covering a surface of the plate-shaped electrode with a dielectric medium to change and guide a pattern of the electric discharge arc.

Fig.10 is a control flow diagram of the method for processing the end surface of the optical fiber by using the system for processing the end surface of the optical fiber of the present invention.

As shown Fig.10, at step SI 00, the system is started to initialize. At step SI 10, determining whether the individual electrode unit and the individual transport unit are correctly communicated to the computer unit. If the determination result is 'no' at the step SI 10, then the control flow goes to step SI 12. At the step SI 12, determining whether it needs to connect the electrode unit or the transport unit. If determining that one of the electrode unit and the transport unit is not connected at the step SI 12, then the control flow goes to SI 14. At the step SI 14, manually starting and setting the operation parameters of the unit until completing the setting of the operation parameters of the unit.

If the determination result is 'yes' at the step SI 10, then the control flow goes to step S120. At the step S120, determining whether to operate the default parameters of the system. If the determination result is 'no' at the step S120, then the control flow goes to step SI 22 to set the parameters of the system, otherwise, the control flow goes to step SI 30. At the step SI 30, determining whether to calibrate the position of the work piece. After the position of the work piece is calibrated, the control flow goes to step S140. At the step S140, acquiring the positions of the work piece (for example, the end surface of the optical fiber) and the electrodes by the camera. The position parameters of the electrodes in the electrode head and the position parameters of the work piece in the transport unit are set through software stored in the computer unit. After the software interface is set correctly, starting to calibrate the position of the work piece.

At step SI 50, processing, analyzing and determining the acquired images, and the determination result is transferred to the first controller of the transport unit and the second controller of the electrode head. Thereafter, at step SI 60, controlling the first, second and third drivers by the first and second controllers to adjust the positions of the electrodes and the optical fiber. And then, at step SI 70, determining whether the positions of the electrodes and the optical fiber satisfy the setting requirements. If the determination result is 'yes' at the step SI 70, then determining whether to start discharge at step SI 80. If performing a discharge operation on the work piece to be processed, then displaying the image

information of the work piece processed by discharge at step S 182, the discharge operation can be repeated by the software or by controlling the panel control keys. Thereafter, at step SI 84, determining whether to reset the work piece to the original position. If it needs to reset the work piece, then the gripping mechanism is reset to the original point at step SI 86, for facilitating to take out the work piece. Hereto, the discharge process on the work piece is finished.

Although the system for processing the end surface of the optical fiber is applied to a cylindrical optical fiber in the above embodiments, the system for processing the end surface of the optical fiber of the present invention may be applied to a ribbon-shaped optical fiber. That is, the optical fiber of the present invention may comprise a cylindrical optical fiber or a ribbon-shaped optical fiber.

The system for processing the end surface of the optical fiber according to the above embodiments of the present invention provides an automatic apparatus with a plurality of electrodes for discharging. When the system is applied to process the surface of the nonmetal material, especially the surface of a micro optical device (for example, the end surface of the cylindrical optical fiber or the ribbon-shaped optical fiber), the processed end surface of the optical fiber becomes very uniform and can be repeatedly achieved. Thereby, the processed surface of the optical fiber by the system of the present invention can be directly spliced with other optical fibers without needing to be processed by other mechanical processes. Further, the system of the present invention can flexibly process the end surface of the optical fiber, and can effectively reduce the power consumption of the electrodes. Furthermore, the system for processing the end surface of the optical fiber of the present invention adopts a plasma discharge device with a small volume to process the end surface of the optical fiber, therefore, the user can easily mount the plasma discharge device in the field.

Moreover, in the system and the method for processing the end surface of the optical fiber according to the present invention, the end surface of the optical fiber is automatically processed by an electric discharge arc, so that the glass surfaces of the optical fibers are melt and spliced together, eliminating tiny cracks in the end surface of the optical fiber, reducing the surface roughness of the end surface of the optical fiber, improving the fatigue strength of the end surface of the optical fiber, and increasing the service life of the optical connection.

In the system for processing the end surface of the optical fiber according to the present invention, the distance between any two electrodes, the position and posture of the work piece to be processed in the electric discharge arc area can be freely adjusted within a certain range by incorporating the image pick-up unit and the computer unit.

It should be appreciated for those skilled in this art that the above embodiments are intended to be illustrated, and not restrictive. For example, many modifications may be made to the above embodiments by those skilled in this art, and various features described in different embodiments may be freely combined with each other without conflicting in configuration or principle, so that more kinds of system for processing the end surface of the optical fiber can be achieved with overcoming the technical problem of the present invention.

Although several exemplary embodiments have been shown and described, it would be appreciated by those skilled in the art that various changes or modifications may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.

As used herein, an element recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to "one embodiment" of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments "comprising" or "having" an element or a plurality of elements having a particular property may include additional such elements not having that property.