阅读说明：本技术 电荷泵电路结构及微型电荷泵 (Charge pump circuit structure and miniature charge pump ) 是由 郭梅寒 于 2021-08-25 设计创作，主要内容包括：本发明涉及一种电荷泵电路结构及微型电荷泵,其中,电荷泵电路结构包括：集成于调理电路芯片上的电路模块以及集成于MEMS结构芯片上的电容模块；电路模块与电容模块电性连接,电路模块包含多级相连的电荷泵电路,上级电荷泵电路的输出作为相连的下级电荷泵电路的输入,其中,电容模块连接于最后一级的电荷泵电路中以增加最后一级电荷泵电路的输出。通过上述方式,能够减小产品尺寸,降低生产成本,实现电荷泵小型化和高度集成化。(The invention relates to a charge pump circuit structure and a micro charge pump, wherein the charge pump circuit structure comprises: the circuit module is integrated on the conditioning circuit chip and the capacitor module is integrated on the MEMS structure chip; the circuit module is electrically connected with the capacitor module, the circuit module comprises a plurality of stages of charge pump circuits which are connected, the output of a higher stage charge pump circuit is used as the input of a lower stage charge pump circuit which is connected, and the capacitor module is connected in a last stage charge pump circuit to increase the output of the last stage charge pump circuit. By the mode, the size of a product can be reduced, the production cost is reduced, and the miniaturization and high integration of the charge pump are realized.)

1. A charge pump circuit structure, comprising: the circuit module is integrated on the conditioning circuit chip and the capacitor module is integrated on the MEMS structure chip, the circuit module is electrically connected with the capacitor module, the circuit module comprises a plurality of stages of charge pump circuits which are connected, the output of a higher-level charge pump circuit is used as the input of a lower-level charge pump circuit which is connected, and the capacitor module is connected in a last-level charge pump circuit to increase the output of the last-level charge pump circuit.

2. The charge pump circuit structure of claim 1, wherein the capacitor module comprises an energy storage capacitor, the energy storage capacitor comprises a first electrode plate and a second electrode plate which are oppositely and oppositely arranged, and under the action of voltage, the first electrode plate and the second electrode plate generate an electrostatic attraction force and move relatively to reduce a capacitor gap.

3. The charge pump circuit structure of claim 2, wherein the first electrode plate comprises a first anchor point and a plurality of first cantilever beams disposed on the first anchor point, and a plurality of second cantilever beams are disposed in parallel and spaced apart from each other.

4. The charge pump circuit structure of claim 3, wherein the second electrode plate comprises a second anchor point and a plurality of second cantilever beams disposed on the second anchor point, the number of the second cantilever beams is the same as the number of the first cantilever beams, and the second cantilever beams are paired with the first cantilever beams one by one.

5. The charge pump circuit structure of claim 4, wherein the first electrode plate is provided with a first stopper for limiting a motion process of the second electrode plate to control a distance between capacitors, the second electrode plate is provided with a second stopper for limiting a motion process of the first electrode plate to control a distance between capacitors, the first stopper is disposed at an equal potential to the first electrode plate, and the second stopper is disposed at an equal potential to the second electrode plate.

6. The charge pump circuit structure of claim 5, wherein the first and second cantilever beams are identical in structure, and each cantilever beam comprises a first vertical portion connected to a fixed anchor, a horizontal portion connected to the first vertical portion, and a second vertical portion connected to the horizontal portion, and a first slot is formed between the horizontal portion and the second vertical portion.

7. The charge pump circuit structure as claimed in claim 6, wherein the first stopper includes a vertical section matching with the first slot and a bent section extending along an end of the vertical section toward the second vertical section, a second slot is formed between the vertical section and the bent section, the second vertical section is received in the second slot when the second cantilever beam moves to abut against the first stopper, the vertical section is received in the first slot, and the second stopper has the same structure as the first stopper.

8. The charge pump circuit structure of claim 2, wherein the energy storage capacitors are made of DRIE deep reactive ion etch processed silicon, the thickness of the energy storage capacitors is 5-80 μm, and the capacitor pitch of the energy storage capacitors is 0.5-4 μm in a static state.

9. The charge pump circuit structure of claim 8, wherein the capacitor module comprises a filter capacitor, and the filter capacitor and the energy storage capacitor are processed in the same manner and thickness.

10. A micro charge pump, comprising: the charge pump circuit structure comprises a substrate, a conditioning circuit chip, an MEMS structure chip and the charge pump circuit structure as claimed in any one of claims 1 to 9, wherein the conditioning circuit chip and the MEMS structure chip are sequentially stacked on the substrate from top to bottom, a circuit module in the charge pump circuit structure is integrated on the conditioning circuit chip, and a capacitance module in the charge pump circuit structure is integrated on the MEMS structure chip.

Technical Field

The present invention relates to the field of integrated circuits and micro-electromechanical systems, and more particularly, to a charge pump circuit structure and a micro-charge pump.

Background

Micro-electromechanical systems (MEMS) are developed on the basis of microelectronics, and incorporate micro-sensors, micro-actuators, micro-mechanical structures, micro-power micro-energy sources, signal processing and control circuits, high-performance electronic integrated devices, interfaces, and communication, etc. into a single micro-device or system. MEMS products are typically composed of two parts, a MEMS mechanical structure and signal conditioning circuitry. Common products include MEMS microphones, micro-motors, micro-pumps, micro-vibrators, MEMS optical sensors, MEMS pressure sensors, MEMS gyroscopes, MEMS accelerometers, MEMS humidity sensors, MEMS gas sensors, and the like, as well as integrated products thereof. The MEMS product can be divided into a sensor and an actuator according to its operation characteristics, wherein the actuator generally drives the MEMS structure to generate motion displacement by using inverse piezoelectric effect, electrostatic force, magnetic force, thermal stress, and the like, and the efficiency of converting input physical quantity into displacement is a core index of most MEMS actuators. In the case of an electrostatically driven actuator, the displacement generated by driving the electrostatically driven actuator is proportional to the driving voltage, and therefore, a charge pump circuit for generating a higher driving voltage is often integrated in the driving circuit of the actuator.

Charge pumps, also known as switched capacitor voltage converters, which can step up or down an input voltage, can also be used to generate negative voltages. The basic working principle of the circuit is that power is supplied and charged to the capacitor, the power supply is cut off, the charge charged by the capacitor is isolated, then the capacitor is connected to another circuit, and the just isolated charge is transferred. The flow direction of the charge is controlled by the switch and the alternating signal, so that the amplitude and the polarity of the output voltage of the charge pump are changed.

The charge pump circuit in a typical MEMS signal conditioning circuit chip usually employs an MOM capacitor, i.e., a same-layer metal finger capacitor, or an MIM capacitor, i.e., an interlayer metal plate capacitor. No matter which capacitor is used, the trade-off needs to be made in the capacitance value, the high voltage resistance and the occupied chip area. The complexity and cost of the high-voltage resistant process are significantly higher than those of the common process under the same integrated circuit process line width size, so that in many MEMS products involving high-voltage charge pump circuits, the size and cost of a signal conditioning circuit chip are generally higher than those of an MEMS structure chip, and the size and cost of the final product are correspondingly increased.

Disclosure of Invention

Based on the circuit structure, the invention provides the charge pump circuit structure and the micro charge pump, which can reduce the size of a product, reduce the production cost and realize the miniaturization and high integration of the charge pump.

In order to solve the technical problems, the invention adopts a technical scheme that: there is provided a charge pump circuit structure comprising: the circuit module is integrated on the conditioning circuit chip and the capacitor module is integrated on the MEMS structure chip, the circuit module is electrically connected with the capacitor module, the circuit module comprises a plurality of stages of charge pump circuits which are connected, the output of a higher-level charge pump circuit is used as the input of a lower-level charge pump circuit which is connected, and the capacitor module is connected with a last-level charge pump circuit to increase the output of the last-level charge pump circuit.

According to one embodiment of the invention, the capacitor module comprises an energy storage capacitor, the energy storage capacitor comprises a first electrode plate and a second electrode plate which are oppositely and oppositely arranged, and under the action of voltage, the first electrode plate and the second electrode plate generate electrostatic attraction force and perform relative motion to reduce the capacitor distance.

According to one embodiment of the invention, the first electrode plate comprises a first fixed anchor point and a plurality of first cantilever beams arranged on the first fixed anchor point, and the plurality of first cantilever beams are arranged in parallel and at intervals.

According to an embodiment of the present invention, the second electrode plate includes a second fixed anchor point and a plurality of second cantilever beams disposed on the second fixed anchor point, the number of the second cantilever beams is the same as the number of the first cantilever beams, and the second cantilever beams and the first cantilever beams are paired one by one.

According to an embodiment of the present invention, a first limiting block for limiting a movement process of the second electrode plate to control a distance between capacitors is disposed on the first electrode plate, a second limiting block for limiting a movement process of the first electrode plate to control a distance between capacitors is disposed on the second electrode plate, the first limiting block is disposed at an equal potential to the first electrode plate, and the second limiting block is disposed at an equal potential to the second electrode plate.

According to an embodiment of the present invention, the first cantilever and the second cantilever have the same structure, and the cantilever includes a first vertical portion connected to the fixing anchor, a horizontal portion connected to the first vertical portion, and a second vertical portion connected to the horizontal portion, and a first cutting groove is formed between the horizontal portion and the second vertical portion.

According to an embodiment of the present invention, the first stopper includes a vertical section matching with the first notch and a bent section extending toward the second vertical portion along an end of the vertical section, a second notch is formed between the vertical section and the bent section, when the second electrode plate moves to abut against the first stopper, the second vertical portion is received in the second notch, the vertical section is received in the first notch, and the structure of the second stopper is the same as that of the first stopper.

According to one embodiment of the invention, the energy storage capacitor is made of a silicon structure processed by DRIE deep reactive ion etching, the thickness of the energy storage capacitor is 5-80 μm, and the capacitor spacing of the energy storage capacitor is 0.5-4 μm in a static state.

According to one embodiment of the invention, the capacitor module comprises a filter capacitor, and the filter capacitor and the energy storage capacitor are processed in the same way and have the same thickness.

In order to solve the technical problem, the invention adopts another technical scheme that: there is provided a micro charge pump comprising: the charge pump circuit structure comprises a substrate, a conditioning circuit chip, an MEMS structure chip and the charge pump circuit structure as claimed in any one of claims 1 to 9, wherein the conditioning circuit chip and the MEMS structure chip are sequentially stacked on the substrate from top to bottom, a circuit module in the charge pump circuit structure is integrated on the conditioning circuit chip, and a capacitance module in the charge pump circuit structure is integrated on the MEMS structure chip.

The invention has the beneficial effects that: the circuit module is integrated on the conditioning circuit chip and the capacitor module is integrated on the MEMS structure chip, so that excessive capacitors are prevented from being integrated in the conditioning circuit chip, the size and the cost of the conditioning chip are reduced, and the requirement of the conditioning circuit chip on an expensive high-voltage-resistant processing technology is reduced, so that the overall size and the cost of a final product are reduced, and the miniaturization and the high integration of the charge pump are realized.

Drawings

FIG. 1 is a schematic structural diagram of a micro charge pump according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a charge pump circuit according to an embodiment of the present invention;

fig. 3 is a schematic perspective view of an energy storage capacitor according to a first embodiment of the present invention;

FIG. 4 is a top view of FIG. 3;

fig. 5 is a schematic structural diagram of an energy storage capacitor according to a second embodiment of the present invention;

fig. 6 is a schematic structural diagram of an energy storage capacitor according to a second embodiment of the invention after displacement of an electrode plate.

The meaning of the reference symbols in the drawings is:

100-a miniature charge pump; 1-a substrate; 2-conditioning the circuit chip; 3-MEMS structure chip; 200-charge pump circuit architecture; 10-a circuit module; 20-a capacitive module; c1-energy storage capacitor; c2-filter capacitance; vin-voltage input; GND1 — first voltage output; GND2 — second voltage output; s1 — a first switch; s2 — a second switch; s3 — a third switch; s4-a fourth switch; 211-a first electrode plate; 212-a second electrode plate; 2111-first anchor point; 2112-first cantilever beam; 2113-first stop block; 2121-a second anchor point; 2122-a second cantilever beam; 2123-a second stopper; 2101-first vertical section; 2102-horizontal portion; 2103-a second vertical portion; 2104-a first cut; 2105-a vertical section; 2106-bending section; 2107-second cut.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As shown in fig. 1, which is a schematic structural diagram of a micro charge pump according to an embodiment of the present invention, the micro charge pump 100 includes a substrate 1, a conditioning circuit chip 2, a MEMS chip 3, and a charge pump circuit structure (not shown in the figure), wherein the conditioning circuit chip 2 and the MEMS chip 3 are sequentially stacked on the substrate 1 from top to bottom. The conditioning circuit chip 2 is further provided with functional modules such as a signal amplifier, a filter and power management, and the MEMS structure chip 3 is further provided with functional modules such as a sensor and an actuator.

As shown in fig. 2, which is a schematic diagram of a charge pump circuit structure according to an embodiment of the present invention, the charge pump circuit structure 200 includes a circuit module 10 integrated on a conditioning circuit chip 2 and a capacitor module 20 integrated on a MEMS structure chip 3. The circuit module 10 and the capacitor module 20 are electrically connected by gold wire bonding, eutectic bonding or fusion bonding to realize the function of a complete charge pump. Further, the circuit module 10 includes a plurality of stages of charge pump circuits connected, an output of an upper stage of charge pump circuit is used as an input of a connected lower stage of charge pump circuit, wherein the capacitor module 20 is connected to a last stage of charge pump circuit to increase an output of the last stage of charge pump circuit. In this embodiment, the output voltage of the last stage of the charge pump circuit is the highest.

It should be noted that the MEMS chip 3 of the present embodiment is not specially configured for implementing the charge pump circuit structure 200, and the charge pump circuit structure 200 may be understood as including a part of the MEMS chip 3, that is, the capacitor module 20, and the output voltage of the charge pump circuit structure 200 connected with the capacitor module 20 is used for implementing the functions of other functional modules of the MEMS chip 3, further, the capacitor module 20 may be a module having an independent energy storage function or a module on the MEMS chip 3 that combines other functions and an energy storage function.

The micro charge pump 100 of the embodiment avoids integrating too many capacitors in the conditioning circuit chip 2 by integrating the circuit module 10 on the conditioning circuit chip 2 and integrating the capacitor module 20 on the MEMS structural chip 3, thereby reducing the size and cost of the conditioning circuit chip 2, and reducing the requirement of the conditioning circuit chip 2 on an expensive high-voltage-resistant processing technology, thereby reducing the overall size and cost of a final product, and realizing the miniaturization and high integration of the charge pump.

Further, the capacitor module 20 of the present embodiment at least includes an energy storage capacitor C1, referring to fig. 2, the capacitor module 20 includes: an energy storage capacitor C1 for charging and discharging and a filter capacitor C2 for noise reduction; further, the energy storage capacitor C1 is made of a silicon structure processed by drie (deep Reactive Ion etching), the thickness of the energy storage capacitor C1 is 5-80 μm, the capacitor spacing of the energy storage capacitor C1 is 0.5-4 μm in a static state, and the filter capacitor C2 and the energy storage capacitor C1 of the embodiment are processed in the same manner and thickness. Can realize through this mode that energy storage capacitor C1 and filter capacitor C2 have great electrode just to the area, because the capacitance value is directly proportional with the electrode just to the area, with electric capacity interval inverse ratio, so, when the electrode just to the area increase, can increase the capacitance value, reduce the filter cutoff frequency, thereby reduce energy storage capacitor C1 and relapse the discharge in-process and cause the ripple that voltage fluctuation and produced, and when the charge pump exported higher voltage, energy storage capacitor C1 is not punctured.

Further, referring to fig. 2, taking an example that the circuit module 10 includes a first stage charge pump circuit as an illustration, the circuit module 10 includes: a voltage input terminal Vin, a first voltage output terminal GND1, a second voltage output terminal GND2, a first switch S1, a second switch S2, a third switch S3 and a fourth switch S4, wherein the second switch S2 and the third switch S3 are connected in parallel and are connected with the voltage input terminal Vin, the third switch S3 is connected in series with the first switch S1, the first switch S1 is connected with the first voltage output terminal GND1, the second switch S2 is connected in series with the fourth switch S4, the fourth switch S4 is connected with the second voltage output terminal GND2, an energy storage capacitor C1 is connected in series between the second switch S2 and the first switch S1, a filter capacitor C2 is connected in series between the fourth switch S4 and the second voltage output terminal GND2, and the first voltage output terminal 1 and the second voltage output terminal 2 are a common ground terminal GND; the first switch S1 and the second switch S2 are closed, the third switch S3 and the fourth switch S4 are opened at the same time, the voltage at two ends of the energy storage capacitor C1 is the input voltage, the third switch S3 and the fourth switch S4 are closed, the first switch S1 and the second switch S2 are opened at the same time, and the voltage at two ends of the filter capacitor C2 is twice of the input voltage.

Further, referring to fig. 3 and 4, the energy storage capacitor C1 includes a first electrode plate 211 and a second electrode plate 212 that are disposed opposite to each other and facing each other, and the polarities of the first electrode plate 211 and the second electrode plate 212 are opposite to each other, and under the action of voltage, the first electrode plate 211 and the second electrode plate 212 generate electrostatic attraction and move relatively to reduce the capacitor gap. Since the capacitance value is inversely proportional to the capacitance pitch, the capacitance value can be increased when the capacitance pitch is reduced. The first electrode plate 211 and the second electrode plate 212 of the present embodiment may be moved simultaneously or separately.

Further, referring to fig. 3 and 4, the second electrode plate 212 and the first electrode plate 211 may have the same or different structures. In this embodiment, the first electrode plate 211 includes a first fixed anchor 2111 and a plurality of first cantilevers 2112 disposed on the first fixed anchor 2111, and the plurality of first cantilevers 2112 are disposed in parallel and at intervals. Specifically, the second electrode plate 212 includes a second anchor 2121 and a plurality of second cantilever beams 2122 disposed on the second anchor 2121, and the plurality of second cantilever beams 2122 are disposed in parallel and spaced apart from each other. The number of second cantilever beams 2122 is the same as the number of first cantilever beams 2112, and second cantilever beams 2122 and first cantilever beams 2112 are paired one by one. The distance between the first cantilever beam 2112 and the second cantilever beam 2122 in the pair is the capacitance distance, and the capacitance distance is 0.5-4 μm in a static state. The first arm beam 2112 may follow the movement when the first electrode plate 211 moves, and the second arm beam 2122 may follow the movement when the second electrode plate 212 moves.

In another embodiment, the second electrode plate 212 and the first electrode plate 211 may have the same or different structures. The first electrode plate 211 includes a first fixing anchor 2111, a first supporting frame (not shown), a first elastic beam (not shown), and a first cantilever 2112, wherein the first cantilever 2112 is fixed on the first supporting frame, and the first supporting frame is fixed on the first fixing anchor 2111 through the first elastic beam. The second electrode plate 212 includes a second anchor 2121, a second support frame (not shown), a second flexible beam (not shown), and a second cantilever beam 2122, wherein the second cantilever beam 2122 is fixed to the second support frame, and the second support frame is fixed to the second anchor 2121 via the second flexible beam. The electrostatic force generated by the first electrode plate 211 and the second electrode plate 212 of this embodiment causes the elastic beam to bend, and the elastic beam drives the cantilever beam and the support frame to move together.

Further, referring to fig. 5, a first limiting block 2113 for limiting a movement process of the second cantilever beam 2122 to control a distance between capacitors is disposed on the first electrode plate 211, a second limiting block 2123 for limiting a movement process of the first cantilever beam 2112 to control a distance between capacitors is disposed on the second electrode plate 212, the first limiting block 2113 is disposed at an equal potential to the first electrode plate 211, and the second limiting block 2123 is disposed at an equal potential to the second electrode plate 212. In this embodiment, the number of the first limiting blocks 2113 is the same as that of the second cantilever beams 2122, the first limiting blocks 2113 are arranged in one-to-one correspondence with the second cantilever beams 2122, the number of the second limiting blocks 2123 is the same as that of the first cantilever beams 2112, and the second limiting blocks 2123 are arranged in one-to-one correspondence with the first cantilever beams 2112. This embodiment has set up the stopper of control electric capacity interval lower limit, ensures that two plate electrodes of energy storage electric capacity C1 can not produce the actuation because of electrostatic force, and the touching can not take place for the positive and negative electrode of energy storage electric capacity, has also improved the resistant high voltage ability of capacitor structure simultaneously. The stopper sets up with the plate electrode equipotential that is blockked, can not take place the charge loss after guaranteeing the plate electrode touching stopper.

Further, referring to fig. 5, the first cantilever 2112 and the second cantilever 2122 have the same structure, and each cantilever includes a first vertical portion 2101 connected to the fixed anchor, a horizontal portion 2102 connected to the first vertical portion 2101, and a second vertical portion 2103 connected to the horizontal portion 2102, and a first cut 2104 is formed between the horizontal portion 2102 and the second vertical portion 2103.

The first stopper 2113 and the second stopper 2123 have the same structure, the stopper includes a vertical section 2105 matching with the first notch 2104 and a bent section 2106 extending toward the second vertical portion 2103 along an end of the vertical section 2105, a second notch 2107 is formed between the vertical section 2105 and the bent section 2106, when the second cantilever 2122 moves to abut against the first stopper 2113, as shown in fig. 6, the second vertical portion 2103 is received in the second notch 2107, and the vertical section 2105 is received in the first notch 2104; when the first cantilever 2112 is moved into abutment with the second stop block 2123, the second vertical portion 2103 is received in the second slot 2107 and the vertical segment 2105 is received in the first slot 2104. First cantilevered beam 2112 and second cantilevered beam 2122 of the present embodiment may move simultaneously or separately.

Further, the structure of the filter capacitor C2 is the same as that of the energy storage capacitor C1, the structure of the energy storage capacitor C1 is described in detail above, and the structure of the filter capacitor C2 is not described in detail herein. This embodiment reduces noise in the output voltage of the charge pump by adding a filter capacitor C2 to the second voltage output GND 2.

In one embodiment, the thickness of the energy storage capacitor C1 is 60um, and the static capacitor spacing is 2 um. When the high voltage generated by the micro charge pump 100 is loaded at two ends of the electrode of the energy storage capacitor C1, the electrostatic attraction forces the two electrode plates to displace so as to reduce the capacitor distance, but the capacitor distance is limited to 0.2um by the limiting block, and at this time, the cantilever beam touches the limiting block, but the charge leakage cannot be caused. At this time. The capacitor spacing is reduced by 10 times compared with the static state, and the capacitance is increased by 10 times.

The charge pump circuit structure 200 of the present embodiment replaces MOM and MIM capacitors in the charge pump circuit in the conditioning circuit chip 2 by adding an additional special capacitor structure that can be connected to the conditioning chip in the MEMS structure chip 3, thereby balancing the sizes and costs of the MEMS structure chip 3 and the conditioning circuit chip 2, also reducing the requirements of the conditioning circuit chip 2 on the expensive high-voltage resistant processing technology, and further reducing the overall size and cost of the final product. In addition, the capacitor module 20 can be ensured to reduce the capacitor distance as much as possible by adding a limiting block in the capacitor structure, so that the capacitance value is improved as much as possible, and the high-voltage output requirement is met and the capacitor module is protected from being damaged. Therefore, the capacitor module 20 of this embodiment can not only realize improving the capacitance value, but also improve the high voltage resistance and simultaneously reduce the occupied chip area, and compared with the conventional MOM capacitor or MIM capacitor, it is not necessary to take the trade off between the realization of the capacitance value, the high voltage resistance and the occupied chip area.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only express preferred embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.