JP2004170455A - Laser processing apparatus, laser processing system and solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser processing apparatus and a laser processing system to minimize the spacing of lines processed by laser on a thin film of a solar cell or the like, and to provide a solar cell. <P>SOLUTION: The laser processing apparatus 10 is equipped with: an X-axis driving motor (table driving mechanism as the scanning mechanism) 20 to drive an X-axis stage 16; a Y-axis driving motor (table driving mechanism as the scanning mechanism) 22 to drive a Y-axis stage 18; table driving controlling mechanism (scanning and position correction mechanism) 24 to control driving of these; and a length measuring system 25 to irradiate the object with laser light and to detect the reflected light to measure the positional error in the X-axis direction and the Y-axis direction of the X-axis stage 16 and the Y-axis stage 18, respectively. Further, the apparatus is equipped with: a laser oscillator 26 to emit the laser light for processing a solar cell 12 with the laser light; and a plurality of laser optics 27 to disperse the laser light emitting from the laser oscillator 26 into a plurality of beams and to adjust the irradiation positions and directions of the laser beams onto a solar cell 12. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing apparatus, a laser processing system, and a solar cell that process, for example, a film body on a substrate constituting the solar cell with a laser beam.
[0002]
[Prior art]
Conventionally, a laser processing apparatus is used to form a separation groove in a thin film on a substrate such as a solar cell.
[0003]
The conventional laser processing apparatus includes a mounting table that holds a substrate on which a thin film that is a film body is formed, a laser oscillator that emits laser light for laser processing the thin film, and a laser beam emitted from the laser oscillator. And a scanning mechanism for scanning the thin film on the thin film.
In this laser processing apparatus, the irradiation position of the laser beam is fixed, the laser beam is scanned by moving the mounting table freely in the horizontal direction (X-axis and Y-axis directions), and a part of the thin film is laser-beamed. The separation groove is formed by sublimation with the heat of.
[0004]
In the case of a solar cell, a transparent electrode layer is formed on a glass substrate, a solar cell layer is formed on the transparent electrode layer, and a back electrode layer is formed on the solar cell layer. Due to the insulation treatment between the respective layers, a processing line for separation grooves is formed on the film by the above laser processing apparatus after the respective thin films are formed (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-150161 (FIG. 1)
[0006]
[Problems to be solved by the invention]
However, in the above conventional laser processing apparatus, in consideration of the positioning error of the mounting table, the interval A (=) between the processing lines as shown in FIG. 6 so that the processing lines (L1, L2, L3) do not intersect each other. (Approximately 60 to 100 μm) must be ensured, but from the viewpoint of the power generation efficiency of the solar cell, this area is a useless area with respect to the power generation area of the solar cell. It was necessary to reduce the interval between the processing lines.
[0007]
The present invention has been made in view of the above circumstances, and provides a laser processing apparatus, a laser processing system, and a solar cell that minimize the interval between processing lines laser processed on each thin film such as a solar cell. Objective.
[0008]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
The laser processing apparatus of the present invention includes a mounting table that holds a substrate on which a film body is formed, a laser oscillator that emits laser light for laser processing the film body, and a laser beam emitted from the laser oscillator. A laser processing apparatus including a scanning mechanism that scans on a film body, the laser processing apparatus including a scanning position correction mechanism that controls the scanning mechanism to correct an error in a processing position during the scanning. .
[0009]
Since this laser processing apparatus is provided with a scanning position correction mechanism that corrects an error in the processing position during laser beam scanning, the laser beam can be scanned with high positioning accuracy.
[0010]
The laser processing apparatus according to the present invention is the laser processing apparatus according to claim 1, wherein the scanning position correction mechanism performs the correction based on movement error data of the mounting table measured in advance. .
[0011]
Since this laser processing apparatus performs correction based on the movement error data of the mounting table measured in advance, the error of the scanning position can be corrected accurately, and high-precision processing is possible.
[0012]
The laser processing apparatus of the present invention is the laser processing apparatus according to claim 1 or 2, wherein the scanning position correction mechanism includes a processing mark detector for measuring a position of the laser-processed processing mark, and the measured processing. The correction is performed based on an error in the position of the mark.
[0013]
This laser processing apparatus includes a processing mark detector, and the scanning position correction mechanism corrects the scanning position of the scanning mechanism based on the laser processing mark position data by the detector, so that an error obtained from an actual processing mark is obtained. The data enables more accurate correction.
[0014]
The laser processing apparatus of the present invention is the laser processing apparatus according to any one of claims 1 to 3, wherein the scanning mechanism includes a table driving mechanism that drives movement of the mounting table, and the scanning position correction is performed. The mechanism controls the table driving mechanism to perform the correction.
[0015]
In this laser processing apparatus, since the scanning position correction mechanism controls the table driving mechanism to perform correction, high-precision correction can be performed with relatively simple control.
[0016]
The laser processing apparatus of the present invention is the laser processing apparatus according to claim 1, wherein the scanning mechanism includes a laser optical system that adjusts a scanning position and a direction of the laser light, and the scanning The position correction mechanism controls the laser optical system to perform the correction.
[0017]
In this laser processing apparatus, since the scanning position correction mechanism controls the laser optical system to perform correction, it has higher responsiveness than the case of controlling the mounting table side, and is controlled with high accuracy on the mounting table side. Even an area that cannot be corrected can be corrected with high accuracy.
[0018]
The laser processing apparatus of the present invention is the laser processing apparatus according to claim 5, comprising a plurality of the laser optical systems that simultaneously perform the laser processing, and all the laser optical systems by one scanning position correction mechanism. The correction is performed by controlling the above simultaneously.
[0019]
Since this laser processing apparatus is provided with one scanning position correction mechanism for correcting at the same time, a plurality of processing lines can be corrected and formed at the same time.
[0020]
The laser processing system of the present invention includes a substrate, a first electrode layer formed on the substrate, a solar cell layer formed of a semiconductor on the first electrode layer, and the solar cell layer. A laser processing system comprising a plurality of laser processing devices for separately processing each of the layers of a solar cell including a second electrode layer formed thereon to form a separation groove, the laser processing device Is a laser processing apparatus according to any one of claims 1 to 6.
[0021]
Since this laser processing system includes the laser processing apparatus according to any one of claims 1 to 6, the processing is performed by correcting the separation grooves (processing lines) individually and appropriately for each film formation of the solar cell. be able to.
[0022]
In the laser processing system of the present invention, the laser processing apparatus that performs laser processing on at least one of the solar cell layer and the second electrode layer is the laser processing apparatus according to claim 3, wherein the processing mark detector The processing trace to be detected is a separation groove of the first electrode layer or the solar cell layer.
[0023]
In this laser processing system, since the processing mark detected by the processing mark detector is the separation groove (processing line) of the first electrode layer or solar cell layer, the first electrode layer or solar cell layer processed in advance It is possible to process the solar cell layer or the second electrode layer with high accuracy based on the actual measurement error of the processing line.
[0024]
The solar cell of the present invention is characterized by being laser processed by the laser processing apparatus or the laser processing system according to any one of claims 1 to 8.
[0025]
Since this solar cell is manufactured from the laser processing apparatus or the laser processing system according to any one of claims 1 to 8, the interval between the processing lines is small, and high power generation efficiency is obtained by improving the power generation area.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention.
In the figure, a laser processing apparatus 10 includes an X-axis stage (mounting table) 16 that holds a glass substrate (substrate) 14 of a solar cell 12 and scans in one horizontal direction (hereinafter referred to as X-axis direction), and X A Y-axis stage (mounting table) 18 that scans the axis stage in a direction perpendicular to the horizontal X-axis (hereinafter referred to as the Y-axis direction) is provided.
[0027]
The laser processing apparatus 10 also includes an X-axis drive motor (scanning mechanism: table drive mechanism) 20 that drives the X-axis stage 16 and a Y-axis drive motor (scanning mechanism: table drive mechanism) that drives the Y-axis stage 18. 22, a table drive control mechanism (scanning position correction mechanism) 24 that controls these drives, and a length measuring system 25 that measures errors in the X-axis direction and the Y-axis direction of the X-axis stage 16 and the Y-axis stage 18. It has.
[0028]
The laser processing apparatus 10 further includes a laser oscillator 26 that emits laser light for laser processing the solar cell 12, and an irradiation position and direction on the solar cell 12 by dispersing a plurality of laser beams emitted from the laser oscillator 26. And a plurality of laser optical systems 27 for adjusting.
[0029]
The laser optical system 27 converges the beam diameter circle, a galvanometer mirror 28 that changes the traveling direction of the laser light emitted from the laser oscillator 26, an Fθ lens 30 that corrects a beam diameter circle of the inclined laser light, and the beam diameter circle. Condensing lens 32 is comprised.
The laser optical systems 27 are arranged in a line in the Y axis direction at a predetermined interval.
[0030]
As shown in FIG. 2, in the solar cell 12, a transparent electrode layer (film body: first electrode) 34 made of a TCO film is formed on a glass substrate 14, and the solar cell made of amorphous silicon is formed on the transparent electrode layer. A layer (film body) 36 is formed, and a back electrode layer (film body: second electrode) 38 made of Ag (silver) is formed on the solar cell layer 36.
[0031]
In the solar cell 12, when the transparent electrode layer 34 is formed on the glass substrate 14, a transparent electrode processing line (processing trace: separation groove) 40 is processed to insulate the transparent electrodes. Subsequently, when the solar cell layer 36 is formed on the transparent electrode layer 34, a solar cell layer processing line (processing trace: separation groove) 42 for communicating the transparent electrode layer 34 and the back electrode layer 38 is processed. Is done. Thereafter, when the back electrode layer 38 is formed on the solar cell layer 36, the back electrode processing line (processing mark: separation groove) 44 is laser processed to insulate the back electrode layers.
[0032]
The laser processing apparatus 10 that performs the series of processes described above includes a transparent electrode layer laser processing apparatus 10A that processes the transparent electrode processing line 40, a solar cell layer laser processing apparatus 10B that processes the solar cell layer processing line 42, and a back surface. The back surface electrode layer laser processing apparatus 10C for processing the electrode processing line 44 is individually installed, and a laser processing system for solar cell processing is configured by these three laser processing apparatuses.
[0033]
Next, a method for correcting a processing position and a method for manufacturing a solar cell by the laser processing apparatus 10 having the above configuration will be described.
First, a transparent electrode layer 34 is formed on the glass substrate 14 shown in FIG. 2 (a) as shown in FIG. 2 (b). Next, as shown in FIG. The transparent electrode processing line 40 is laser processed by the layer laser processing apparatus 10A. The processing line is processed by moving the X-axis stage 16 in the X-axis direction relative to the laser beam.
[0034]
That is, first, before machining, the length measuring system 25, which is a precise measuring means prepared separately, measures in advance the error data of the position in the X-axis direction and the Y-axis direction along with the movement of the X-axis stage 16, and obtains the data. It is stored in the table drive control mechanism 24.
The error data may be automatically stored in the table drive control mechanism 24.
[0035]
When forming the transparent electrode processing line 40, the laser optical system 27 is adjusted so that the laser light emitted from the laser oscillator 26 is irradiated onto the transparent electrode layer 34. Thereby, the irradiation direction of the laser beam is fixed.
Subsequently, the X-axis drive motor 20 is driven by the table drive control mechanism 24 to move the X-axis stage 16 in the X-axis direction while holding the solar cell 12.
[0036]
At this time, the table drive control mechanism 24 calculates the direction and distance in which the position error in the X-axis direction and the Y-axis direction recorded in the error data at that position is to be corrected, and the X-axis drive motor 20 and the Y-axis. The axis drive motor 22 is driven and controlled to move the X axis stage 16 and the Y axis stage 18.
[0037]
Thus, when the transparent electrode processing line 40 is formed, the Y-axis stage 18 is moved by a predetermined distance in the Y-axis direction, and the transparent electrode processing line is continuously moved to a new location on the transparent electrode layer 34 by the above-described method. Is processed.
[0038]
After the processing of the transparent electrode layer 34 is completed, the solar cell layer 36 is formed as shown in FIG. 2D, and the solar cell layer 36 is formed by the same processing method as described above as shown in FIG. The solar cell layer processing line 42 is formed by the battery layer laser processing apparatus 10B.
Further, when the back electrode layer 38 is formed as shown in FIG. 2 (f), the back electrode is formed by the back electrode layer laser processing apparatus 10C by the same processing method as described above, as shown in FIG. 2 (g). A processing line 44 is formed.
In this way, a modularized solar cell 12 is produced.
[0039]
According to the laser processing apparatus 10, since the straightness error of the X-axis stage 16 is corrected when processing the processing line, the interval between adjacent processing lines can be reduced. At this time, since each laser optical system is corrected simultaneously, a plurality of processing lines can be simultaneously corrected and formed in the same manner.
In addition, since the correction is performed in the same manner in each laser processing apparatus for each line, it is possible to secure high-accuracy line positions with each other, and the solar cells manufactured thereby obtain high power generation efficiency by improving the power generation area. It is done.
[0040]
Next, a second embodiment according to the present invention will be described with reference to FIG. In the following description, the same reference numerals are given to the components described in the above embodiment, and the description thereof is omitted.
[0041]
The difference between the second embodiment and the first embodiment is that a laser processing apparatus 52 including a laser optical system 50 is adjusted to a beam diameter circle in place of the galvano mirror 28 and the Fθ lens 30, and a laser is used. A plurality of oscillating mechanisms (scanning mechanisms) 54 using an AOM (acoustic optic modulator) that finely moves light in the Y-axis direction, and a laser optical system control mechanism (scanning position correction mechanism) that controls driving of these oscillating mechanisms 54 ) 58 is provided.
The table control mechanism 59 that drives and controls the X-axis drive motor 20 and the Y-axis drive motor 22 of the laser processing apparatus 52 is configured not to take into account positional errors of the X-axis stage 16 and the Y-axis stage 18.
Note that the same correction method may be used in combination by the table control mechanism 24 as in the first embodiment.
[0042]
The processing position correction method and the solar cell manufacturing method by the laser processing apparatus 52 having the above-described configuration will be described with respect to differences from the first embodiment.
When the transparent electrode processing line 40 is formed, the laser optical system control mechanism 58 causes the position error in the X-axis direction and the Y-axis direction of the X-axis stage 16 and the Y-axis stage 18 recorded in the error data at the position. The direction and distance to be corrected are calculated, and the swing mechanism 54 is driven and controlled to swing the irradiation position of the laser beam.
[0043]
Thus, when the transparent electrode processing line 40 is formed, the Y-axis stage 18 is moved by a predetermined distance in the Y-axis direction, and the transparent electrode processing line is continuously moved to a new location on the transparent electrode layer 34 by the above-described method. Is processed.
Further, by the same processing method as described above, the solar cell layer laser processing device 52B, which is the laser processing device 52, forms the solar cell layer processing line 42, and the back electrode layer laser processing device 52C forms the back electrode processing line 44. A modularized solar cell 12 is produced.
[0044]
According to this laser processing apparatus 52, since the laser optical system 50 is controlled by the laser optical system control mechanism 58 to perform correction, the responsiveness is higher than when the X-axis stage 16 and the Y-axis stage 18 are controlled. At the same time, it can be corrected with high accuracy.
[0045]
Next, a third embodiment according to the present invention will be described with reference to FIG. In the following description, the same reference numerals are given to the components described in the above embodiment, and the description thereof is omitted.
[0046]
The difference between the third embodiment and the above embodiment is that the laser processing apparatus 60 includes an image processing sensor (processing mark detector) 62 that detects the transparent electrode processing line 40 processed by the above embodiment. Is a point.
The image processing sensor 62 includes a CCD or the like, and performs processing such as binarization of the detected image to measure the position of the processing line.
Further, the laser processing device 60 is provided with a table drive control mechanism 64 that drives and controls the X-axis drive motor 20 and the Y-axis drive motor 22 based on the data detected by the image processing sensor 62.
[0047]
The processing position correction method and solar cell manufacturing method by the laser processing apparatus 60 having the above-described configuration will be described with respect to differences from the first and second embodiments.
First, a reference transparent electrode processing line (processing trace: separation groove) 40a is formed by the transparent electrode layer laser processing apparatus 10A or the transparent electrode layer laser processing apparatus 52A. Subsequently, when forming the solar cell layer processing line 42, the X-axis direction and the Y-axis direction of the reference transparent electrode processing line 40 a are detected by the image processing sensor 62 of the solar cell layer laser processing device 60 B which is the laser processing device 60. The amount of swell, which is the error of, is detected.
[0048]
At this time, the table drive control mechanism 64 calculates the direction and distance in which the swell amount at the position is to be corrected, and drives and controls the X-axis drive motor 20 and the Y-axis drive motor 22 to control the X-axis stage 16 and The Y axis stage 18 is moved. Thus, a highly accurate solar cell layer processing line 42 whose position is corrected is formed.
Similarly, when processing the back electrode processing line 44, the transparent electrode processing line 40a and the solar cell layer processing line 42 are detected by the image processing sensor 62, and the same correction is performed based on the amount of waviness at this time. Perform laser processing.
[0049]
According to the laser processing apparatus 60, the image processing sensor 62 performs processing while detecting an existing processing line, so that correction with higher accuracy is possible.
[0050]
Next, a fourth embodiment according to the present invention will be described with reference to FIG. In the following description, the same reference numerals are given to the components described in the above embodiment, and the description thereof is omitted.
[0051]
The difference between the fourth embodiment and the third embodiment is that the laser processing apparatus 70 drives the laser optical system 72 to correct the error.
In other words, the laser optical system 72 is provided with a laser optical system control mechanism 74 that drives and controls the swing mechanism 54 based on data detected by the image processing sensor 62.
Further, the laser processing apparatus 70 is provided with the table drive control mechanism 59 in the second embodiment.
[0052]
The processing position correction method and the solar cell manufacturing method by the laser processing apparatus 70 having the above-described configuration will be described with respect to differences from the first to third embodiments.
First, when forming the solar cell layer processing line 42, the image processing sensor 62 detects the amount of undulation, which is an error in the position of the processing trace of the reference transparent electrode processing line 40a in the X-axis direction and the Y-axis direction.
[0053]
At the same time, the laser optical system control mechanism 74 drives and controls the rocking mechanism 54 based on the amount of waviness, and rocks the irradiation position of the laser light in accordance with the distance for which the amount of waviness is to be corrected.
[0054]
According to this laser processing apparatus 70, high-accuracy processing of the solar cell layer 36 or the back electrode layer 38 is highly responsive based on the measurement error of the processing line of the transparent electrode layer 34 or the solar cell layer 36 processed in advance. It becomes possible with. Further, the processing line can be corrected individually and appropriately for each solar cell film formation.
[0055]
In the third and fourth embodiments, when forming a reference processing line, processing may be performed according to the first and second embodiments.
Further, the laser processing apparatus constituting the laser processing system 46 may be combined with any of the above embodiments.
[0056]
【The invention's effect】
The present invention described above has the following effects.
Since the laser processing apparatus of the present invention is equipped with a scanning position correction mechanism that corrects an error in the processing position during laser beam scanning, the laser beam can be scanned with high positioning accuracy, and the solar cell has high power generation efficiency. Can be obtained.
[0057]
Since the laser processing apparatus of the present invention performs correction based on the movement error data of the mounting table measured in advance, it is possible to accurately correct the scanning position error in consideration of the movement error in advance, and relatively simple control. Thus, high-precision processing becomes possible, and a solar cell with high power generation efficiency can be obtained.
[0058]
The laser processing apparatus of the present invention includes a processing mark detector, and the scanning position correction mechanism includes a scanning position correction mechanism that corrects the scanning position of the scanning mechanism based on the laser processing mark position data by the detector. The error data obtained from the actual processing trace enables correction with higher accuracy, and a solar cell with high power generation efficiency can be obtained.
[0059]
Since the laser processing system of the present invention is equipped with the laser processing apparatus of the present invention, the measurement error of the first electrode layer of the solar cell processed in advance or the separation groove (processing line) of the solar cell layer is reduced. Based on this, high-precision processing of the solar cell layer or the second electrode layer is possible, and a solar cell with high power generation efficiency can be obtained.
[0060]
Since the solar cell of the present invention is manufactured by the laser processing system of the present invention, high power generation efficiency is obtained by improving the power generation area due to the small interval between the processing lines.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a laser processing apparatus of a laser processing system according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of a principal part for explaining the processing process of the solar cell in the first embodiment of the present invention in the order of steps.
FIG. 3 is a schematic configuration diagram showing a laser processing apparatus of a laser processing system according to a second embodiment of the present invention.
FIG. 4 is a schematic configuration diagram showing a laser processing apparatus of a laser processing system according to a third embodiment of the present invention.
FIG. 5 is a schematic configuration diagram showing a laser processing apparatus of a laser processing system according to a fourth embodiment of the present invention.
FIG. 6 is an explanatory diagram showing the positional relationship of a solar cell processing line by a conventional laser processing apparatus.
[Explanation of symbols]
10, 52, 60, 70 Laser processing apparatus 10A, 52A, 60A, 70A Transparent electrode layer laser processing apparatus (laser processing apparatus)
10B, 52B, 60B, 70B Solar cell layer laser processing device (laser processing device)
10C, 52C, 60C, 70C Laser processing device for back electrode layer (laser processing device)
12 Solar cell 14 Glass substrate (substrate)
16 X-axis stage (mounting table)
18 Y-axis stage (mounting table)
20 X-axis drive motor (scanning mechanism: table drive mechanism)
22 Y-axis drive motor (scanning mechanism: table drive mechanism)
24, 59, 64 Table drive control mechanism (scanning position correction mechanism)
26 Laser oscillators 27, 50, 72 Laser optical system 34 Transparent electrode layer (film body: first electrode layer)
36 Solar cell layer (film body)
38 Back electrode layer (film body: second electrode layer)
40 Transparent electrode processing line (processing trace: separation groove)
40a Standard transparent electrode processing line (processing mark: separation groove)
42 Solar cell layer processing line (processing trace: separation groove)
44 Back electrode processing line (processing trace: separation groove)
46 Laser processing system 54 Oscillation mechanism (scanning mechanism)
58, 74 Laser optical system drive control mechanism (scanning position correction mechanism)
62 Image processing sensor (processing mark detector)

Claims (9)

A mounting table that holds a substrate on which a film body is formed, a laser oscillator that emits laser light for laser processing the film body, and a scanning mechanism that scans the laser light emitted from the laser oscillator onto the film body A laser processing apparatus comprising:
A laser processing apparatus comprising a scanning position correction mechanism that controls the scanning mechanism to correct an error in a processing position during the scanning. The laser processing apparatus according to claim 1, wherein the scanning position correction mechanism performs the correction based on movement error data of the mounting table measured in advance. The scanning position correction mechanism includes a processing mark detector that measures the position of the laser processed processing mark,
The laser processing apparatus according to claim 1, wherein the correction is performed based on an error in the position of the measured processing mark. The scanning mechanism includes a table driving mechanism that drives the movement of the table.
The laser processing apparatus according to claim 1, wherein the scanning position correction mechanism performs the correction by controlling the table driving mechanism. The scanning mechanism includes a laser optical system that adjusts the scanning position and direction of the laser light,
The laser processing apparatus according to claim 1, wherein the scanning position correction mechanism performs the correction by controlling the laser optical system. A plurality of the laser optical systems for performing the laser processing simultaneously,
6. The laser processing apparatus according to claim 5, wherein the correction is performed by simultaneously controlling all the laser optical systems by one scanning position correction mechanism. A substrate, a first electrode layer formed on the substrate, a solar cell layer formed of a semiconductor on the first electrode layer, and a second layer formed on the solar cell layer A laser processing system comprising a plurality of laser processing devices for separately processing each layer of a solar cell including an electrode layer to form separation grooves,
The laser processing apparatus according to claim 1, wherein the laser processing apparatus is a laser processing apparatus according to claim 1. The laser processing apparatus according to claim 3, wherein the laser processing apparatus that performs laser processing on at least one of the solar cell layer and the second electrode layer is a laser processing apparatus according to claim 3.
The laser processing system, wherein the processing mark detected by the processing mark detector is a separation groove of the first electrode layer or the solar cell layer. A solar cell that is laser-processed by the laser processing apparatus or laser processing system according to claim 1.

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