WO2011052541A1 - Testing device and testing method - Google Patents
Testing device and testing method Download PDFInfo
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- WO2011052541A1 WO2011052541A1 PCT/JP2010/068861 JP2010068861W WO2011052541A1 WO 2011052541 A1 WO2011052541 A1 WO 2011052541A1 JP 2010068861 W JP2010068861 W JP 2010068861W WO 2011052541 A1 WO2011052541 A1 WO 2011052541A1
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- preform
- scattered light
- forward scattered
- hole
- inspection apparatus
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
- G01M11/37—Testing of optical devices, constituted by fibre optics or optical waveguides in which light is projected perpendicularly to the axis of the fibre or waveguide for monitoring a section thereof
Definitions
- the present invention relates to a preform which is a preform of an optical fiber in which holes are formed, that is, a preform inspection apparatus and a method for inspection in which a through hole is formed.
- a photonic crystal fiber is an optical fiber in which the refractive index of the cladding is reduced by holes, and it is known that optical characteristics that cannot be obtained by conventional optical fibers in which the refractive index of the cladding is reduced by impurities are obtained. It has been.
- the photonic crystal fiber includes (1) a preform manufacturing process for manufacturing a columnar base material made of silica glass (hereinafter referred to as “preform”), (2 It is manufactured through a through-hole forming step for forming a through-hole serving as a base material for holes in the preform, and (3) a drawing step for drawing the preform with the through-hole formed therein.
- preform a columnar base material made of silica glass
- through holes extending from one end surface of the preform to the other end surface in a direction perpendicular to these end surfaces are formed by drilling. For this reason, if the machining accuracy of the machine tool that forms the through hole is low, the drilling position gradually shifts as the drilling progresses even if drilling starts from an appropriate position on one end surface, and the other end surface penetrates. Large positional displacement of the holes may occur, or the through holes may be connected on the way. For this reason, after forming a through-hole, it is necessary to test
- the inspection of whether or not the through-hole is formed at an appropriate position is generally performed by a method of observing the preform from the end surface direction using an optical microscope.
- Japanese Published Patent Publication “JP 2002-145634” (published on May 22, 2002) Japanese Patent Publication “JP 2002-249335” (published on September 6, 2002) Japanese Patent Publication “JP 2002-293562 A” (published on October 9, 2002) Japanese Patent Publication “Japanese Patent Laid-Open No. 2006-160528” (published on June 22, 2006)
- the conventional inspection method using an optical microscope has a problem that it can inspect only the formation positions of holes near the end face of the preform. That is, there has been a problem that the formation position of the through hole cannot be inspected in the middle of both end faces (arbitrary cross section between both end faces).
- An intermediate through-hole formation position is also estimated from a hole formation position on one end face and a hole formation position on the other end face. The position where the hole is formed cannot be specified with high accuracy. For this reason, when the through hole formation position on the end face is greatly deviated from the proper position, it is necessary to examine which part can be used for manufacturing an optical fiber by cutting the preform. This increases the manufacturing cost.
- the present invention has been made in view of the above problems, and its purpose is to determine whether or not the through hole is formed at an appropriate position in the middle of both end faces of the preform without destroying the preform.
- the object is to realize an inspection apparatus and inspection method that can be confirmed well.
- an inspection apparatus is an inspection apparatus that inspects a cylindrical preform having a through-hole, and is generated by allowing light to enter from a side surface of the preform.
- Detection means for successively detecting the intensity distribution of the forward scattered light of the preform, and rotating the preform around the center axis of the preform or moving the detection means so as to go around the preform
- Rotating / moving means for calculating, and calculating means for calculating a time series of feature values having values corresponding to the arrangement of the through holes from the intensity distribution of the forward scattered light detected sequentially. It is said.
- inspection method which concerns on this invention is a test
- a rotation / movement step for moving the detection means a calculation step for calculating a time series of feature amounts having values corresponding to the arrangement of the through holes from the intensity distribution of the forward scattered light detected sequentially, and the features And a determination step of determining whether or not the through hole is formed at a predetermined position based on a time series of quantities.
- the time series of feature values calculated from the intensity distribution of the forward scattered light detected sequentially while rotating the preform around the central axis or moving the detection means to circulate around the preform is the through hole. It shows different behavior depending on whether it is formed at an appropriate position. For this reason, referring to the time series of the feature amounts, it can be accurately confirmed whether or not the through hole is formed at a predetermined position without destroying the preform.
- the upper stage is a graph showing the intensity distribution of forward scattered light obtained when a parallel light beam is irradiated to a preform having no through-holes
- the lower stage is a cross-sectional view of such a preform.
- the upper row is a graph showing the intensity distribution of forward scattered light obtained when parallel rays are irradiated to a preform having through holes formed at appropriate positions
- the lower row is a cross-sectional view of such a preform. It is.
- the upper graph is a graph showing the intensity distribution of forward scattered light obtained when a parallel beam is irradiated to a preform in which one through-hole is displaced, and the lower graph is a cross section of such a preform.
- FIG. The upper graph is a graph showing the intensity distribution of forward scattered light obtained when a parallel beam is irradiated to a preform in which two through holes are displaced, and the lower graph is a cross section of such a preform.
- FIG. It is sectional drawing of the ideal preform in which all the through-holes were formed in the appropriate position. It is a graph which shows the time series of the dark part width
- FIG. 5 is a graph showing a time series of dark part widths in the intensity distribution of forward scattered light obtained by rotating the preform shown in the lower part of FIG. 4. It is a graph which shows the time series of the dark part width
- the upper graph is a graph showing the intensity distribution of forward scattered light obtained when a parallel beam is irradiated to a preform in which all the through holes are uniformly displaced, and the lower graph is a graph showing such a profile. It is sectional drawing of reform.
- the upper graph is a graph showing the intensity distribution of forward scattered light obtained when parallel rays are irradiated to a preform in which all through holes are formed at appropriate positions
- the lower graph is a graph of such a preform. It is sectional drawing.
- the upper graph is a graph showing the intensity distribution of forward scattered light obtained when a parallel beam is irradiated to a preform in which all the through holes are uniformly displaced
- the lower graph is a graph showing such a profile. It is sectional drawing of reform.
- the upper graph is a graph showing the intensity distribution of forward scattered light obtained when parallel rays are irradiated to a preform in which all through holes are formed at appropriate positions
- the lower graph is a graph of such a preform.
- the upper graph is a graph showing the intensity distribution of forward scattered light obtained when a parallel beam is irradiated to a preform in which all the through holes are uniformly displaced, and the lower graph is a graph showing such a profile. It is sectional drawing of reform.
- the upper graph is a graph showing the intensity distribution of forward scattered light obtained when parallel rays are irradiated to a preform in which all through-holes are shifted by 3 mm from the preform central axis. It is sectional drawing of such a preform.
- 12 is a graph showing a time series of an integral value difference
- FIG. 16 is a graph showing a time series of an integral value difference
- FIG. 14 is a graph showing a time series of a bright part width difference
- FIG. 15 is a graph showing a time series of a bright portion width difference
- optical fiber in each embodiment described below refers to an optical fiber in which one or more holes extending in the central axis direction are formed unless otherwise specified.
- preform a preform that is a base material of an optical fiber in which one or more holes are formed, that is, one or more penetrations. It refers to a preform in which holes are formed.
- the inspection apparatus is an inspection apparatus suitable for detecting a positional shift that has occurred in some of the through holes formed in the preform.
- FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of an inspection apparatus 100 according to the present embodiment.
- the inspection apparatus 100 is an apparatus for inspecting whether or not the through hole 11 is formed at a predetermined appropriate position in each cross section of the preform 10, and as shown in FIG. Device (detecting means) 102, rotating mechanism (rotating / moving means) 103, parallel moving mechanism (parallel moving means) 104, computing unit 105 (calculating means), determining unit 106, and position detecting unit 107.
- the light source 101 is a means for irradiating the preform 10 with parallel rays from the side surface, and is, for example, an LED (Light Emitting Diode).
- the parallel rays irradiated to the preform 10 are repeatedly refracted and reflected at the boundary separating the inside and outside of the preform 10 and the boundary separating the inside and outside of the through hole 11, and forward on the opposite side of the preform 10 from the light source 101 side. This produces scattered light.
- the forward scattered light generated in this way is hereinafter simply referred to as “forward scattered light of the preform 10”.
- the detector 102 is means for sequentially detecting the intensity distribution of the forward scattered light of the preform 10. More specifically, in a plane opposite to the light source 101 side of the preform 10 and orthogonal to the parallel rays irradiated from the light source 101, the plane is orthogonal to the orthogonal projection of the central axis of the preform 10. This is means for sequentially detecting the intensity distribution on the straight line.
- a detector 102 can be realized, for example, by arranging a CCD (Charge-Coupled Device) line sensor along this straight line.
- the rotation mechanism 103 is a means for rotating the preform 10 gripped by the grip portion 103a with the central axis (of the preform 10) as the rotation axis. By rotating the preform 10 using the rotation mechanism 103, it becomes possible to sequentially detect the forward scattered light of the preform 10 in each direction. Instead of adopting a configuration in which the preform 10 is rotated using the rotation mechanism 103 as in the present embodiment, a configuration in which the light source 101 and the detector 102 are moved so as to go around the preform 10 is the same. It becomes possible.
- the translation mechanism 104 is a means for translating the light source 101 and the detector 102 held by the holding unit 104a in the central axis direction of the preform 10. While the preform 10 is rotated about the central axis using the rotation mechanism 103, the light source 101 and the detector 102 are translated using the parallel movement mechanism 104, whereby forward scattered light of the preform 10 in each direction. Can be detected for each cross section.
- the preform 10 is moved in the central axis direction. The same can be achieved even if the configuration is adopted.
- the intensity distribution of the forward scattered light of the preform 10 has a dark portion corresponding to the “shadow” of the through hole 11 as described later.
- the computing unit 105 is means for sequentially calculating the width of the dark part (hereinafter abbreviated as “dark part width”) from the intensity distribution of the forward scattered light sequentially detected by the detector 102.
- the determination unit 106 is a unit for determining whether or not the through hole 11 is formed at a predetermined appropriate position based on the time series of the dark part width sequentially calculated by the calculation unit 105. Note that a method for determining whether or not the through hole 11 is formed at a predetermined appropriate position based on the time series of the dark part width will be described later with reference to another drawing.
- the position detector 107 is a means for detecting the positions of the light source 101 and the detector 102.
- the determination unit 106 outputs or records a determination result indicating whether or not the through-hole 11 is properly arranged in association with the positions of the light source 101 and the detector 102 detected by the position detection unit 107. Therefore, by referring to the information output or recorded by the determination unit 106, it is possible to know in which cross section of the preform 10 the arrangement of the through holes 11 is disturbed.
- FIG. 2 The upper part of FIG. 2 is a graph showing the intensity distribution of the forward scattered light obtained when the parallel light beam 20 is irradiated to the preform 10 ′ in which no through-hole is formed, and the lower part of FIG. 2 is a cross-sectional view of a preform 10 ′.
- the parallel light beam 20 incident on the preform 10 ′ is refracted when entering the preform 10 ′ from the air and when entering the air from the preform 10 ′.
- the other side of the reform 10 ' is reached.
- the intensity distribution of the forward scattered light of the preform 10 ' becomes a smooth intensity distribution having one peak at the center as shown in the upper part of FIG.
- FIG. 3 The upper part of FIG. 3 is a graph showing the intensity distribution of the forward scattered light obtained when the parallel light beam 20 is applied to the preform 10 in which the through-holes 11 are formed at appropriate positions, and the lower part of FIG. FIG. 2 is a cross-sectional view of such a preform 10.
- the intensity distribution of the forward scattered light of the preform 10 is an intensity distribution having two peaks and a dark part sandwiched between these two peaks, as shown in the upper part of FIG.
- the “dark width” refers to the distance between these two peaks.
- the dark portion width periodically changes.
- the through-hole 11 is arranged on the apex of a regular hexagon centering on the central axis of the preform 10, it passes through the central axis of the preform 10 and is perpendicular to the parallel light beam 20.
- the dark part width takes the maximum value L 0 and the two through-holes 11 are simultaneously formed on the straight line passing through the central axis of the preform 10 and parallel to the parallel light beam 20.
- the dark space width takes the minimum value. If the time series of the dark part width obtained when the preform 10 is rotated as shown in the lower part of FIG. 3 is plotted, a sine waveform is obtained as shown in FIG.
- FIG. 4 The upper part of FIG. 4 is a graph showing the intensity distribution of the forward scattered light obtained when the parallel light beam 20 is irradiated to the preform 10 in which one through hole 11a is displaced.
- the lower part of FIG. These are sectional views of such a preform 10. The point where the intensity distribution of the forward scattered light has two peaks and a dark part sandwiched between these two peaks is the case where the through hole 11 is formed at an appropriate position as shown in the upper part of FIG. It is the same.
- the lower preform 10 in FIG. 4 is different from the lower preform 10 in FIG. 3 in that one through hole 11a is formed to be shifted outward. Therefore, passing through the central axis of the preform 10, the dark area width when the through-hole 11a that misaligned perpendicular straight line into parallel beams 20 are arranged to take the maximum value L 1 (L 1> L 0 ).
- L 1 L 1> L 0
- the through hole 11 a when the through hole 11 a is formed so as to be displaced inward, the through hole 11 a causing the positional displacement is arranged on a straight line that passes through the central axis of the preform 10 and is perpendicular to the parallel light beam 20.
- the dark part width at the time does not reach the maximum value.
- the upper part of FIG. 5 is a graph showing the intensity distribution of forward scattered light obtained when the preform 10 in which the two through-holes 11a and 11b are displaced is irradiated with a parallel light beam.
- the lower part is a cross-sectional view of such a preform 10.
- the through hole 11 is formed at an appropriate position in that the intensity distribution of the forward scattered light has two peaks and an intensity distribution having a dark part sandwiched between these two peaks. It is the same as if
- the lower preform 10 in FIG. 5 differs from the lower preform 10 in FIG. 3 and the lower preform 10 in FIG. 4 in that two through-holes 11 a and 11 b that are opposed to each other via the central axis are formed to be shifted outward. . Therefore, passing through the central axis of the preform 10, the vertical straight line into parallel beams 20, dark portion width when the two through holes 11a ⁇ b are misaligned is disposed a maximum value L 2 (L 2> L 1> L 0).
- L 2 L 2> L 1> L 0
- the through holes 11a and 11b are formed to be displaced inwardly, the through holes 11a and 11b that are misaligned are on a straight line that passes through the central axis of the preform 10 and is perpendicular to the parallel light beam 20.
- the dark portion width when placed in the position does not reach the maximum value.
- FIG. 6 is a cross-sectional view of an ideal preform 10 in which all through holes 11 are formed at appropriate positions.
- the through hole 11 formed in the ideal preform 10 shown in FIG. 6 deviates from an appropriate position to the outside, the dark portion width obtained when the preform 10 is rotated once.
- the maximum value L of the series becomes larger than the maximum value L 0 of the time series of the dark part width obtained when the ideal preform 10 is rotated once.
- the determination unit 106 extracts (1) the time series maximum value L of the dark part width calculated by the calculation unit 105, (2) compares the extracted maximum value L with the threshold Th, and (3) When the extracted maximum value L is larger than the threshold value Th, it is possible to detect that the through-hole 11 has shifted outward from an appropriate position by determining that the “through-hole 11 has shifted outward”.
- the inspection apparatus 100 can be realized.
- the time series maximum value L 0 of the dark part width obtained when the ideal preform 10 is rotated once may be determined by actual measurement or opposed to the ideal preform 10 via the central axis.
- the determination unit 106 (1) extracts all the maximum values included in the time series of the dark portion width calculated by the calculation unit 105, and (2) compares each of the extracted maximum values with the threshold Th. (3) If it is determined that “the through hole 11 is displaced inward” when a maximum value smaller than the threshold Th is present, the through hole 11 may be displaced inward from an appropriate position.
- a detectable inspection apparatus 100 can be realized.
- the determination method for determining that the through-hole 11 is not formed at a predetermined position when the time series of the dark part width has a maximum value exceeding a predetermined threshold has been described. Is not limited to this.
- the time series of the dark part width shows a sine waveform as shown in FIG.
- the waveform is broken as shown in FIGS. Therefore, the time-series frequency spectrum (with one sharp peak) of the dark part width obtained when the ideal preform 10 is rotated once is stored in advance in the memory provided in the determination unit 106. By comparing with the frequency spectrum calculated by the calculation unit 105, it can be appropriately determined whether or not the through hole is formed at an appropriate position.
- the inspection apparatus is an inspection apparatus that inspects a cylindrical preform having a through-hole formed therein, and the above-described profile generated by making a light beam incident from the side surface of the preform.
- Detection means for sequentially detecting the intensity distribution of the forward scattered light of the reform, and rotation for rotating the preform around the center axis of the preform or moving the detection means so as to go around the preform / Moving means, and calculating means for calculating a time series of the dark width from the intensity distribution of the forward scattered light detected sequentially.
- the inspection method is an inspection method for inspecting a cylindrical preform in which a through-hole is formed, and the front of the preform generated by allowing light to enter from a side surface of the preform.
- a dark portion corresponding to the formation position of the through hole is generated in the intensity distribution of the forward scattered light.
- the time series of the dark part width in the intensity distribution of the forward scattered light is: It behaves differently depending on whether or not the through hole is formed at an appropriate position. For this reason, referring to the time series of the dark portion width in the intensity distribution of the forward scattered light calculated by the above configuration, whether the through hole is formed at a predetermined position or not is determined as follows. There is an effect that it can be confirmed with high accuracy without destruction.
- the inspection apparatus further includes a translation unit that translates the preform or the detection unit in the central axis direction of the preform.
- the inspection apparatus compares the time series maximum value or maximum value of the dark part width with a predetermined threshold value to determine whether the through hole is formed at a predetermined position. It is preferable to further comprise determination means for determining.
- the through holes formed in the preform are usually arranged at equal intervals on the circumference centered on the central axis of the preform in order to provide the optical fiber with axial symmetry.
- the maximum value of the time series of the dark part width obtained when the preform is rotated once all the through holes are on the circumference. It becomes larger than the time series maximum value of the dark part width obtained when the formed preform is rotated once. Further, when any of the through holes is displaced inward from the circumference, all the through holes are formed on the circumference in a time series of dark portion widths obtained when the preform is rotated once. A maximum value that does not reach the maximum value of the time series of the dark width obtained when the preform is rotated once appears.
- the time series maximum value of the dark part width obtained when the preform having the through hole formed on the circumference is rotated once is set as a threshold value
- the time series maximum value of the dark part width is determined. Can be accurately determined whether or not the through hole is formed at a predetermined position. Further, when any of the through holes is shifted inward from the circumference, the through hole is formed at a predetermined position by comparing each time series maximum value of the dark portion with this threshold value. It can be accurately determined whether or not there is.
- the inspection apparatus determines whether or not the through hole is formed at a predetermined position by comparing the time-series frequency spectrum of the dark part width with a predetermined frequency spectrum. It is preferable to further comprise determination means.
- the through holes formed in the preform are usually arranged at equal intervals on the circumference centered on the central axis of the preform in order to provide the optical fiber with axial symmetry.
- the time series of the dark part width shows a sine waveform, and when the position shift occurs in the through hole, the time series of the dark part width becomes a sine waveform collapsed. Therefore, by comparing the time-series frequency spectrum of the dark part width with the spectrum of the dark part width obtained when the preform having the through holes arranged at equal intervals on the circumference is rotated once, the through hole becomes circular. There is an effect that it can be accurately determined whether or not they are arranged at equal intervals on the circumference.
- this embodiment A second embodiment (hereinafter referred to as “this embodiment”) of the present invention will be described with reference to FIGS. 10 to 14 and FIGS. 16 to 19.
- the inspection apparatus according to the present embodiment is an inspection apparatus suitable for detecting a uniform positional deviation generated in all through holes formed in the preform.
- FIG. 10 shows a mode of misalignment to be detected in this embodiment.
- the lower part of FIG. 10 is a cross-sectional view of the preform 10 in which all the through holes 11 ′ are uniformly displaced, and the upper part of FIG. 10 shows the parallel light beam 20 with respect to such a preform 10.
- It is a graph which shows intensity distribution of the forward scattered light obtained when it irradiates. As shown in the upper part of FIG. 10, the point that the intensity distribution of the forward scattered light has two peaks and a dark part sandwiched between these two peaks is the same as described above.
- the bright portion of the forward scattered light refers to a region where the intensity of the forward scattered light spreads outside the two peaks and becomes greater than a predetermined intensity Io (explanation).
- a predetermined intensity Io explanation
- the bright part spreading to the left of the dark part is referred to as “first bright part” and the bright part spreading to the right of the dark part is referred to as “second bright part”).
- the lower limit intensity Io that defines the left end of the first bright part and the right end of the second bright part can be set to an arbitrary value of 0 or more.
- the configuration of the inspection apparatus according to this embodiment is the same as that of the inspection apparatus 100 in the first embodiment shown in FIG.
- the calculation unit 105 sequentially calculates the bright part width difference ⁇ W from the intensity distribution of the forward scattered light sequentially detected by the detector 102, A configuration is employed in which the determination unit 106 determines whether or not the through hole 11 is formed at an appropriate position based on the time series of the bright part width difference ⁇ W sequentially calculated by the calculation unit 105.
- FIG. 11 is a cross-sectional view of such a preform 10
- the upper part of FIG. 11 shows the intensity distribution of forward scattered light obtained when such a preform 10 is irradiated with parallel rays 20. It is a graph to show.
- the area on the graph having an area corresponding to the integrated value S1 obtained by integrating the intensity of the forward scattered light on the first bright portion, and the intensity of the forward scattered light are the second A region on the graph having an area corresponding to the integral value S2 obtained by integrating on the bright part is clearly indicated by hatching.
- the intensity of the forward scattered light is integrated on the first bright part as shown in the upper part of FIG.
- the obtained integrated value S1 and the integrated value S2 obtained by integrating the intensity of the forward scattered light on the second bright portion are substantially equal. Even if the preform 10 is rotated, the intensity distribution of the forward scattered light in these two bright portions changes substantially symmetrically with respect to the central axis of the preform 10, so that the integral value S1 and the integral value S2 are substantially equal. Keep on.
- calculated by the calculation unit 105 when the preform 10 in which all the through holes 11 are formed at appropriate positions is an inspection target. . It can be seen from FIG. 16 that the maximum value of the integral value difference ⁇ S
- FIG. 12 The lower part of FIG. 12 is a cross-sectional view of such a preform 10, and the upper part of FIG. 12 shows the intensity distribution of forward scattered light obtained when such a reformer 10 is irradiated with parallel rays 20. It is a graph.
- the region on the graph having an area corresponding to the integrated value S1 obtained by integrating the intensity of the forward scattered light on the first bright portion, and the intensity of the forward scattered light are the second A region on the graph having an area corresponding to the integral value S2 obtained by integrating on the bright part is clearly indicated by hatching.
- calculated by the calculation unit 105 when the preform 10 in which all the through holes 11 ′ are uniformly displaced is the inspection target. Shown in It can be seen from FIG. 17 that each maximum value of the integral value difference ⁇ S
- calculated by the calculation unit 105 with the threshold value ⁇ So. Can be determined. Specifically, when each maximum value of the integral value difference ⁇ S
- calculated by the calculation unit 105 does not exceed the threshold value So, it is determined that the through hole is formed at an appropriate position. When any one of the integral value differences ⁇ S
- FIG. 13 is a sectional view of such a preform 10, and the upper part of FIG. 13 shows the intensity distribution of forward scattered light obtained when such a preform 10 is irradiated with parallel rays 20. It is a graph to show.
- the first bright part width W1 and the second bright part width W2 of the forward scattered light are clearly shown by the lengths of the arrows.
- the first bright part width W1 and the second bright part of the forward scattered light are obtained.
- the part width W2 is substantially equal. Even if the preform 10 is rotated, the intensity distribution of the forward scattered light in these two bright portions changes substantially symmetrically with respect to the central axis of the preform 10, so that the first bright portion width W1 and the second bright portion are changed.
- the part width W2 is kept substantially equal.
- calculated by the calculation unit 105 when the preform 10 in which all the through holes 11 are formed at appropriate positions is an inspection target. Show. It can be seen from FIG. 18 that the maximum value of the bright part width difference ⁇ W
- FIG. 14 is a cross-sectional view of such a preform 10, and the upper part of FIG. 14 shows the intensity distribution of forward scattered light obtained when such a reformer 10 is irradiated with parallel rays 20. It is a graph.
- the difference ⁇ W
- between the bright portion width W1 and the bright portion width W2 shown in the upper part of FIG. 14 takes a local maximum value.
- the time series of the bright part width difference ⁇ W
- calculated by the calculation unit 105 with a predetermined threshold value ⁇ Wo, so that the through hole is formed at an appropriate position. It can be determined whether or not. Specifically, when each local maximum value of the bright part width difference ⁇ W
- calculated by the calculation unit 105 does not exceed the threshold value Wo, it is determined that the through hole is formed at an appropriate position. When any one of the maximum values of the bright part width difference ⁇ W
- the feature quantity that can be used to detect the positional deviation of the through hole is It is not limited to. That is, any feature amount can be used as long as it is a feature amount that can be calculated from the intensity distribution of the forward scattered light and has a value corresponding to the arrangement of the through holes formed in the preform. It can be used to detect the positional deviation of
- Example 1 The effectiveness of the inspection apparatus 100 according to the first embodiment of the present invention was confirmed as follows.
- a preform A having a cross section as shown in the lower part of FIG. Specifically, for a preform having an outer diameter of 90 mm ⁇ , six through-holes having a diameter of 4 mm ⁇ were formed by a drill method at a position 20 mm from the center of the preform.
- the position where one through hole (through hole 11a in FIG. 4) is formed is shifted outward by 4 mm
- two through holes through holes in FIG. 5 are formed.
- the positions of the holes 11a and the through holes 11b) were shifted outward by 4 mm respectively.
- a time series of dark part widths related to the preform A was obtained using the inspection apparatus 100.
- the time-series acquisition of the dark part width is performed by rotating the preform A attached to the rotation mechanism 103 (with the central axis of the preform A as a rotation axis) and the light source 101 and the detector 102 attached to the parallel movement mechanism 104.
- LEDs and a CCD line sensor were used as the light source 101 and the detector 102.
- the rotation speed of the preform was set to 100 rpm
- the moving speed of the LED and the CCD line sensor was set to 10 mm / min
- the sampling period in the CCD line sensor was set to 500 milliseconds.
- the threshold value Th used for the inspection of the preforms B to C is set using this time series.
- the maximum value of the dark space width in this time series is set to L 0
- the threshold value Th is set to a value slightly larger than L 0 , specifically, L 0 +0.5 mm. If the through-hole can be accurately formed at a position 20 mm from the central axis at the time of forming the preform A, the maximum value Lo of the dark part width may be set to 40 mm without being obtained by actual measurement.
- the preforms B to C were inspected using the inspection apparatus 100 according to the first embodiment.
- the inspection is performed by rotating the preforms B to C attached to the rotating mechanism 103 (with the center axis of the preform as the rotating axis) and detecting the light source 101 attached to the parallel moving mechanism 104 and the detection.
- the vessel 102 was moved in parallel along the central axis of the preforms B to C.
- an LED and a CCD line sensor were used as the light source 101 and the detector 102, as in the actual measurement of the dark part width.
- the rotation speed of the preform was set to 100 rpm
- the moving speed of the LED and the CCD line sensor was set to 10 mm / min
- the sampling period in the CCD line sensor was set to 500 milliseconds.
- Example 2 The effectiveness of the inspection apparatus 100 according to the second embodiment of the present invention was confirmed as follows.
- a preform having a cross section as shown in the lower part of FIG. Specifically, for a preform having an outer diameter of 90 mm ⁇ , six through-holes having a diameter of 4 mm ⁇ were formed by a drill method at a position 20 mm from the center of the preform (this preform was formed by using the preform used in Example 1). Since it is the same preform as the reform A, it is also called the preform A in this embodiment).
- the integral value difference ⁇ S is the integral value S1 obtained by integrating the intensity of the forward scattered light on the first bright part and the intensity of the forward scattered light on the second bright part.
- the time series of the integral value difference ⁇ S related to the preform A was obtained using the inspection apparatus 100.
- the integral value difference ⁇ S is obtained by rotating the preform A attached to the rotating mechanism 103 and moving the light source 101 and the detector 102 attached to the parallel moving mechanism 104 along the central axis of the preform A.
- the detection was performed by detecting the intensity distribution of the forward scattered light with the detector 102.
- LEDs and a CCD line sensor were used as the light source 101 and the detector 102.
- the rotation speed of the preform was set to 100 rpm
- the moving speed of the LED and the CCD line sensor was set to 10 mm / min
- the sampling period in the CCD line sensor was set to 500 milliseconds.
- a time series shown in FIG. 16 was obtained as a time series of the integral value difference ⁇ S regarding the preform A.
- the threshold value ⁇ So used for the inspection of the preform D is set using this time series.
- the maximum value of the integrated value difference in this time series is set to ⁇ S max
- the threshold value ⁇ S o is set to a value larger than ⁇ S max , specifically, three times ⁇ S max (see the graph shown in FIG. 16).
- the vertical axis is the logarithm of the area).
- the preform D was inspected using the inspection apparatus 100.
- the preform D attached to the rotation mechanism 103 was rotated (with the central axis of the preform D as the rotation axis) and attached to the parallel movement mechanism 104, as in the actual measurement of the integral value difference ⁇ S related to the preform A.
- the light source 101 and the detector 102 were moved while being translated along the central axis of the preform D.
- the rotation speed of the preform is set to 100 rpm
- the moving speed of the LED and the CCD line sensor is set to 10 mm / min
- the sampling period in the CCD line sensor is set to 500 milliseconds, as in the actual measurement of the integral value difference ⁇ S related to the preform A.
- the time series of the dark part width calculated by the arithmetic unit 105 when the preform D is an inspection target has the waveform shown in FIG. All local maximum values in this time series exceeded the previously set threshold value ⁇ S o .
- the determination unit 106 outputs a determination that “the through hole is displaced” over the entire length direction.
- the bright part width difference ⁇ W refers to the difference
- the time series of the bright part width difference ⁇ W related to the preform A was obtained using the inspection apparatus 100.
- the bright part width difference ⁇ W is acquired by rotating the preform A attached to the rotating mechanism 103 and moving the light source 101 and the detector 102 attached to the parallel moving mechanism 104 along the central axis of the preform A.
- the intensity distribution of the forward scattered light was detected by the detector 102.
- LEDs and a CCD line sensor were used as the light source 101 and the detector 102.
- the rotation speed of the preform was set to 100 rpm
- the moving speed of the LED and the CCD line sensor was set to 10 mm / min
- the sampling period in the CCD line sensor was set to 500 milliseconds.
- the time series shown in FIG. 18 was obtained as the time series of the bright part width difference ⁇ W related to the preform A.
- the threshold ⁇ Wo used for the inspection of the preform D is set using this time series. Specifically, the maximum value of the bright part width difference in this time series is set to ⁇ W max , and the threshold value ⁇ W o is set to a value larger than ⁇ W max , specifically, three times ⁇ W max .
- the preform D was inspected using the inspection apparatus 100.
- the inspection is attached to the parallel movement mechanism 104 while rotating the preform D attached to the rotation mechanism 103 (with the central axis of the preform D as the rotation axis).
- the light source 101 and the detector 102 were moved while being translated along the center axis of the preform D.
- the rotation speed of the preform is set to 100 rpm
- the moving speed of the LED and the CCD line sensor is set to 10 mm / min
- the sampling period in the CCD line sensor is set to 500 milliseconds. Respectively.
- the time series of the bright part width difference ⁇ W calculated by the calculation unit 105 when the preform D is an inspection target has a waveform as shown in FIG. All local maximum values in this time series exceeded the previously set threshold value ⁇ W o . As a result, the determination unit 106 outputs a determination that “the through hole is displaced” over the entire length direction.
- the inspection method according to the present invention can be suitably used for inspection of a preform that is a base material of an optical fiber in which holes are formed, such as a photonic crystal fiber.
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Abstract
A detector (102) successively detects the forward scattering light intensity distributions of a preform (10) generated by making parallel beams incident from the side, while a rotating mechanism (103) rotates the preform (10) using the center axis as a rotating axis. A determination unit (106) determines, based on the time series feature amounts calculated from the forward scattering light intensity distributions, whether through-holes are formed at predetermined positions or not.
Description
本発明は、空孔が形成されている光ファイバの母材となるプリフォーム、すなわち、貫通孔が形成されたプリフォームの検査装置、及び、検査方法に関する。
The present invention relates to a preform which is a preform of an optical fiber in which holes are formed, that is, a preform inspection apparatus and a method for inspection in which a through hole is formed.
長距離伝送に適した光ファイバとして、近年、フォトニック結晶ファイバ(PCF:Photonic Crystal Fiber)が注目を集めている。フォトニック結晶ファイバは、空孔によってクラッドの屈折率を低下させた光ファイバであり、不純物によってクラッドの屈折率を低下させた従来型の光ファイバでは得られなかった光学特性を得られることが知られている。
In recent years, photonic crystal fibers (PCFs) have attracted attention as optical fibers suitable for long-distance transmission. A photonic crystal fiber is an optical fiber in which the refractive index of the cladding is reduced by holes, and it is known that optical characteristics that cannot be obtained by conventional optical fibers in which the refractive index of the cladding is reduced by impurities are obtained. It has been.
フォトニック結晶ファイバは、特許文献1~4に記載のように、(1)シリカガラスからなる円柱状の母材(以下「プリフォーム」と呼称する)を作製するプリフォーム作製工程と、(2)空孔の母体となる貫通孔をプリフォームに形成する貫通孔形成工程と、(3)貫通孔が形成されたプリフォームを線引きする線引工程とを経て製造される。
As described in Patent Documents 1 to 4, the photonic crystal fiber includes (1) a preform manufacturing process for manufacturing a columnar base material made of silica glass (hereinafter referred to as “preform”), (2 It is manufactured through a through-hole forming step for forming a through-hole serving as a base material for holes in the preform, and (3) a drawing step for drawing the preform with the through-hole formed therein.
フォトニック結晶ファイバにおいては、空孔の位置がその光学特性に大きく影響する。したがって、所望の光学特性を有する光ファイバを製造するためには、プリフォームにおいて貫通孔を予め定められた適正な位置に形成することが重要である。
In photonic crystal fibers, the position of holes greatly affects the optical characteristics. Therefore, in order to manufacture an optical fiber having desired optical characteristics, it is important to form a through hole at a predetermined appropriate position in the preform.
貫通孔形成工程においては、ドリル穿孔加工によりプリフォームの一方の端面から他方の端面に至る、これらの端面と垂直な方向に伸びる貫通孔を形成する。このため、貫通孔を形成する工作機械の加工精度が低いと、一方の端面の適正な位置から穿孔を開始しても、穿孔を進めるにつれて穿孔位置が徐々にずれていき、他方の端面において貫通孔の大きな位置ずれが生じたり、貫通孔同士が途中で繋がってしまったりする。このため、貫通孔を形成した後に、貫通孔が適正な位置に形成されているか否かを検査することが必要になる。
In the through hole forming step, through holes extending from one end surface of the preform to the other end surface in a direction perpendicular to these end surfaces are formed by drilling. For this reason, if the machining accuracy of the machine tool that forms the through hole is low, the drilling position gradually shifts as the drilling progresses even if drilling starts from an appropriate position on one end surface, and the other end surface penetrates. Large positional displacement of the holes may occur, or the through holes may be connected on the way. For this reason, after forming a through-hole, it is necessary to test | inspect whether the through-hole is formed in the appropriate position.
貫通孔が適正な位置に形成されているか否かの検査は、従来、光学顕微鏡を用いてプリフォームを端面方向から観察する方法で行われることが一般的であった。
Conventionally, the inspection of whether or not the through-hole is formed at an appropriate position is generally performed by a method of observing the preform from the end surface direction using an optical microscope.
しかしながら、光学顕微鏡を用いた従来の検査方法では、プリフォームの端面近傍における空孔の形成位置しか検査できないという問題があった。すなわち、両端面の中間(両端面間の任意の断面)における貫通孔の形成位置を検査できないという問題があった。一方の端面における空孔の形成位置と他方の端面における空孔の形成位置とから中間における貫通孔の形成位置を推定することも行われているが、このような推定では両端面の中間における空孔の形成位置を精度よく特定できない。このため、端面における貫通孔の形成位置が適正な位置から大きく外れている場合には、どの部分が光ファイバの製造に使える部分であるかを、プリフォームを輪切りにして調べてみる必要があり、製造コストの増大を招く。
However, the conventional inspection method using an optical microscope has a problem that it can inspect only the formation positions of holes near the end face of the preform. That is, there has been a problem that the formation position of the through hole cannot be inspected in the middle of both end faces (arbitrary cross section between both end faces). An intermediate through-hole formation position is also estimated from a hole formation position on one end face and a hole formation position on the other end face. The position where the hole is formed cannot be specified with high accuracy. For this reason, when the through hole formation position on the end face is greatly deviated from the proper position, it is necessary to examine which part can be used for manufacturing an optical fiber by cutting the preform. This increases the manufacturing cost.
本発明は上記の問題に鑑みてなされたものであり、その目的は、プリフォームの両端面の中間において貫通孔が適正な位置に形成されているか否かを、プリフォームを破壊することなく精度よく確認することができる検査装置及び検査方法を実現することにある。
The present invention has been made in view of the above problems, and its purpose is to determine whether or not the through hole is formed at an appropriate position in the middle of both end faces of the preform without destroying the preform. The object is to realize an inspection apparatus and inspection method that can be confirmed well.
上記課題を解決するために、本発明に係る検査装置は、貫通孔が形成された円柱状のプリフォームを検査する検査装置であって、上記プリフォームの側面から光線を入射させることにより生じた上記プリフォームの前方散乱光の強度分布を逐次検出する検出手段と、上記プリフォームの中心軸を回転軸として上記プリフォームを回転させるか、又は、上記プリフォームを周回するよう上記検出手段を移動させる回転/移動手段と、逐次検出された上記前方散乱光の強度分布から、上記貫通孔の配置に応じた値をもつ特徴量の時系列を算出する算出手段とを備えている、ことを特徴としている。
In order to solve the above problems, an inspection apparatus according to the present invention is an inspection apparatus that inspects a cylindrical preform having a through-hole, and is generated by allowing light to enter from a side surface of the preform. Detection means for successively detecting the intensity distribution of the forward scattered light of the preform, and rotating the preform around the center axis of the preform or moving the detection means so as to go around the preform Rotating / moving means for calculating, and calculating means for calculating a time series of feature values having values corresponding to the arrangement of the through holes from the intensity distribution of the forward scattered light detected sequentially. It is said.
また、上記課題を解決するために、本発明に係る検査方法は、貫通孔が形成された円柱状のプリフォームを検査する検査方法であって、上記プリフォームの側面から光線を入射させることにより生じた上記プリフォームの前方散乱光の強度分布を検出手段によって逐次検出する検出工程と、上記プリフォームの中心軸を回転軸として上記プリフォームを回転させるか、又は、上記プリフォームを周回するよう上記検出手段を移動させる回転/移動工程と、逐次検出された上記前方散乱光の強度分布から、上記貫通孔の配置に応じた値をもつ特徴量の時系列を算出する算出工程と、上記特徴量の時系列に基づいて、上記貫通孔が予め定められた位置に形成されているか否かを判定する判定工程とを含んでいる、ことを特徴としている。
Moreover, in order to solve the said subject, the test | inspection method which concerns on this invention is a test | inspection method which test | inspects the cylindrical preform in which the through-hole was formed, Comprising: By making a light ray enter from the side surface of the said preform A detection step of sequentially detecting the intensity distribution of the forward scattered light of the preform generated by the detection means, and the preform is rotated with the central axis of the preform as a rotation axis, or the preform is circulated. A rotation / movement step for moving the detection means, a calculation step for calculating a time series of feature amounts having values corresponding to the arrangement of the through holes from the intensity distribution of the forward scattered light detected sequentially, and the features And a determination step of determining whether or not the through hole is formed at a predetermined position based on a time series of quantities.
中心軸を回転軸としてプリフォームを回転させながら、あるいは、プリフォームを周回するよう検出手段を移動させながら逐次検出した前方散乱光の強度分布から算出される特徴量の時系列は、貫通孔が適正な位置に形成されているか否かによって異なる振る舞いを示す。このため、この特徴量の時系列を参照すれば、貫通孔が予め定められた位置に形成されているか否かをプリフォームを破壊することなく精度よく確認することができる。
The time series of feature values calculated from the intensity distribution of the forward scattered light detected sequentially while rotating the preform around the central axis or moving the detection means to circulate around the preform is the through hole. It shows different behavior depending on whether it is formed at an appropriate position. For this reason, referring to the time series of the feature amounts, it can be accurately confirmed whether or not the through hole is formed at a predetermined position without destroying the preform.
本発明によれば、貫通孔が予め定められた位置に形成されているか否かをプリフォームを破壊することなく精度よく確認することができる。
According to the present invention, whether or not the through hole is formed at a predetermined position can be accurately confirmed without destroying the preform.
本発明の実施形態について図面に基づいて説明すれば以下のとおりである。なお、以下に説明する各実施形態において「光ファイバ」と記載した場合には、特に断りのない限り、中心軸方向に伸びる1つ以上の空孔が形成された光ファイバを指す。また、本実施形態において「プリフォーム」と記載した場合には、特に断りのない限り、1つ以上の空孔が形成された光ファイバの母材となるプリフォーム、すなわち、1つ以上の貫通孔が形成されたプリフォームを指す。
Embodiments of the present invention will be described with reference to the drawings as follows. It should be noted that the term “optical fiber” in each embodiment described below refers to an optical fiber in which one or more holes extending in the central axis direction are formed unless otherwise specified. Further, when “preform” is described in the present embodiment, unless otherwise specified, a preform that is a base material of an optical fiber in which one or more holes are formed, that is, one or more penetrations. It refers to a preform in which holes are formed.
<第1の実施形態>
本発明の第1の実施形態(以下、「本実施形態」と記載)について、図1~図9を参照して説明する。本実施形態に係る検査装置は、プリフォームに形成された複数の貫通孔のうち、一部の貫通孔に生じた位置ずれを検出するのに好適な検査装置である。 <First Embodiment>
A first embodiment of the present invention (hereinafter referred to as “this embodiment”) will be described with reference to FIGS. The inspection apparatus according to the present embodiment is an inspection apparatus suitable for detecting a positional shift that has occurred in some of the through holes formed in the preform.
本発明の第1の実施形態(以下、「本実施形態」と記載)について、図1~図9を参照して説明する。本実施形態に係る検査装置は、プリフォームに形成された複数の貫通孔のうち、一部の貫通孔に生じた位置ずれを検出するのに好適な検査装置である。 <First Embodiment>
A first embodiment of the present invention (hereinafter referred to as “this embodiment”) will be described with reference to FIGS. The inspection apparatus according to the present embodiment is an inspection apparatus suitable for detecting a positional shift that has occurred in some of the through holes formed in the preform.
〔検査装置〕
本実施形態に係る検査装置について、図1を参照して説明する。図1は、本実施形態に係る検査装置100の概略構成を示す概略構成図である。 [Inspection equipment]
The inspection apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of aninspection apparatus 100 according to the present embodiment.
本実施形態に係る検査装置について、図1を参照して説明する。図1は、本実施形態に係る検査装置100の概略構成を示す概略構成図である。 [Inspection equipment]
The inspection apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of an
検査装置100は、プリフォーム10の各断面において貫通孔11が予め定められた適正な位置に形成されているか否かを検査するための装置であり、図1に示すように、光源101、検出器(検出手段)102、回転機構(回転/移動手段)103、平行移動機構(平行移動手段)104、演算部105(算出手段)、判定部106、及び、位置検出部107を備えている。
The inspection apparatus 100 is an apparatus for inspecting whether or not the through hole 11 is formed at a predetermined appropriate position in each cross section of the preform 10, and as shown in FIG. Device (detecting means) 102, rotating mechanism (rotating / moving means) 103, parallel moving mechanism (parallel moving means) 104, computing unit 105 (calculating means), determining unit 106, and position detecting unit 107.
光源101は、プリフォーム10に側面から平行光線を照射するための手段であり、例えば、LED(Light Emitting Diode)である。プリフォーム10に照射された平行光線は、プリフォーム10の内外を隔てる境界、及び、貫通孔11の内外を隔てる境界において屈折及び反射を繰り返し、プリフォーム10の光源101側とは反対側に前方散乱光を生じる。このようにして生じた前方散乱光を、以下、「プリフォーム10の前方散乱光」と簡潔に記載する。
The light source 101 is a means for irradiating the preform 10 with parallel rays from the side surface, and is, for example, an LED (Light Emitting Diode). The parallel rays irradiated to the preform 10 are repeatedly refracted and reflected at the boundary separating the inside and outside of the preform 10 and the boundary separating the inside and outside of the through hole 11, and forward on the opposite side of the preform 10 from the light source 101 side. This produces scattered light. The forward scattered light generated in this way is hereinafter simply referred to as “forward scattered light of the preform 10”.
検出器102は、プリフォーム10の前方散乱光の強度分布を逐次検出する手段である。より具体的には、プリフォーム10の光源101側とは反対側にある平面であって、光源101から照射された平行光線と直交する平面において、プリフォーム10の中心軸の正射影に直交する直線上の強度分布を逐次検出するための手段である。このような検出器102は、例えば、CCD(Charge Coupled Device)ラインセンサをこの直線に沿って配置することにより実現することができる。
The detector 102 is means for sequentially detecting the intensity distribution of the forward scattered light of the preform 10. More specifically, in a plane opposite to the light source 101 side of the preform 10 and orthogonal to the parallel rays irradiated from the light source 101, the plane is orthogonal to the orthogonal projection of the central axis of the preform 10. This is means for sequentially detecting the intensity distribution on the straight line. Such a detector 102 can be realized, for example, by arranging a CCD (Charge-Coupled Device) line sensor along this straight line.
回転機構103は、把持部103aにより把持したプリフォーム10を、その(プリフォーム10の)中心軸を回転軸として回転させるための手段である。回転機構103を用いてプリフォーム10を回転させることによって、各方向に対するプリフォーム10の前方散乱光を逐次検出することが可能になる。なお、本実施形態のように回転機構103を用いてプリフォーム10を回転させる構成を採用する代わりに、プリフォーム10を周回するよう光源101及び検出器102を移動する構成を採用しても同様のことが可能になる。
The rotation mechanism 103 is a means for rotating the preform 10 gripped by the grip portion 103a with the central axis (of the preform 10) as the rotation axis. By rotating the preform 10 using the rotation mechanism 103, it becomes possible to sequentially detect the forward scattered light of the preform 10 in each direction. Instead of adopting a configuration in which the preform 10 is rotated using the rotation mechanism 103 as in the present embodiment, a configuration in which the light source 101 and the detector 102 are moved so as to go around the preform 10 is the same. It becomes possible.
平行移動機構104は、保持部104aにより保持した光源101及び検出器102を、プリフォーム10の中心軸方向に平行移動させるための手段である。回転機構103を用いてプリフォーム10を中心軸を回転軸として回転させながら、平行移動機構104を用いて光源101及び検出器102を平行移動させることによって、各方向に対するプリフォーム10の前方散乱光を各断面について検出することが可能になる。なお、本実施形態のように平行移動機構104を用いて光源101及び検出器102をプリフォーム10の中心軸方向に平行移動させる構成を採用する代わりに、プリフォーム10をその中心軸方向に移動させる構成を採用しても同様のことが可能になる。
The translation mechanism 104 is a means for translating the light source 101 and the detector 102 held by the holding unit 104a in the central axis direction of the preform 10. While the preform 10 is rotated about the central axis using the rotation mechanism 103, the light source 101 and the detector 102 are translated using the parallel movement mechanism 104, whereby forward scattered light of the preform 10 in each direction. Can be detected for each cross section. Instead of adopting a configuration in which the light source 101 and the detector 102 are translated in the central axis direction of the preform 10 using the translation mechanism 104 as in the present embodiment, the preform 10 is moved in the central axis direction. The same can be achieved even if the configuration is adopted.
プリフォーム10の前方散乱光の強度分布は、後述するように、貫通孔11の「影」に相当する暗部をもつ。演算部105は、検出器102により逐次検出された前方散乱光の強度分布から、この暗部の幅(以下「暗部幅」と略記する)を逐次算出するための手段である。判定部106は、演算部105により逐次算出された暗部幅の時系列に基づいて、貫通孔11が予め定められた適正な位置に形成されているか否かを判定するための手段である。なお、暗部幅の時系列に基づいて貫通孔11が予め定められた適正な位置に形成されているか否かを判定する方法については、参照する図面を代えて後述する。
The intensity distribution of the forward scattered light of the preform 10 has a dark portion corresponding to the “shadow” of the through hole 11 as described later. The computing unit 105 is means for sequentially calculating the width of the dark part (hereinafter abbreviated as “dark part width”) from the intensity distribution of the forward scattered light sequentially detected by the detector 102. The determination unit 106 is a unit for determining whether or not the through hole 11 is formed at a predetermined appropriate position based on the time series of the dark part width sequentially calculated by the calculation unit 105. Note that a method for determining whether or not the through hole 11 is formed at a predetermined appropriate position based on the time series of the dark part width will be described later with reference to another drawing.
位置検出部107は、光源101及び検出器102の位置を検出するための手段である。判定部106は、貫通孔11が適正に配置されているか否かを示す判定結果を、位置検出部107により検出された光源101及び検出器102の位置に関連づけて出力又は記録する。したがって、判定部106により出力又は記録された情報を参照すれば、プリフォーム10のどの断面において貫通孔11の配置が乱れているかを知ることができる。
The position detector 107 is a means for detecting the positions of the light source 101 and the detector 102. The determination unit 106 outputs or records a determination result indicating whether or not the through-hole 11 is properly arranged in association with the positions of the light source 101 and the detector 102 detected by the position detection unit 107. Therefore, by referring to the information output or recorded by the determination unit 106, it is possible to know in which cross section of the preform 10 the arrangement of the through holes 11 is disturbed.
〔前方散乱光の強度分布〕
次に、プリフォームの前方散乱光の強度分布について、図2~5及び図7~9を参照して詳しく説明する。 [Intensity distribution of forward scattered light]
Next, the intensity distribution of the forward scattered light of the preform will be described in detail with reference to FIGS. 2 to 5 and FIGS.
次に、プリフォームの前方散乱光の強度分布について、図2~5及び図7~9を参照して詳しく説明する。 [Intensity distribution of forward scattered light]
Next, the intensity distribution of the forward scattered light of the preform will be described in detail with reference to FIGS. 2 to 5 and FIGS.
図2の上段は、貫通孔が形成されていないプリフォーム10’に対して平行光線20を照射したときに得られる前方散乱光の強度分布を示すグラフであり、図2の下段は、そのようなプリフォーム10’の断面図である。
The upper part of FIG. 2 is a graph showing the intensity distribution of the forward scattered light obtained when the parallel light beam 20 is irradiated to the preform 10 ′ in which no through-hole is formed, and the lower part of FIG. 2 is a cross-sectional view of a preform 10 ′.
図2の下段に示すようにプリフォーム10’に入射する平行光線20は、空気中からプリフォーム10’に入射する際、及び、プリフォーム10’から空気中に入射する際に屈折し、プリフォーム10’の反対側に到達する。その結果、プリフォーム10’の前方散乱光の強度分布は、図2の上段に示すように、中央に1つのピークを有する滑らかな強度分布になる。
As shown in the lower part of FIG. 2, the parallel light beam 20 incident on the preform 10 ′ is refracted when entering the preform 10 ′ from the air and when entering the air from the preform 10 ′. The other side of the reform 10 'is reached. As a result, the intensity distribution of the forward scattered light of the preform 10 'becomes a smooth intensity distribution having one peak at the center as shown in the upper part of FIG.
図3の上段は、貫通孔11が適正な位置に形成されたプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布を示すグラフであり、図3の下段は、そのようなプリフォーム10の断面図である。
The upper part of FIG. 3 is a graph showing the intensity distribution of the forward scattered light obtained when the parallel light beam 20 is applied to the preform 10 in which the through-holes 11 are formed at appropriate positions, and the lower part of FIG. FIG. 2 is a cross-sectional view of such a preform 10.
図3の下段に示すようにプリフォーム10に入射する平行光線20のうち、光軸がプリフォーム10の中心軸から遠い光線は、貫通孔11が形成されていない場合と同様、空気中からプリフォーム10に入射する際、及び、プリフォーム10から空気中に入射する際に屈折し、プリフォーム10の反対側に到達する。一方、図3の下段に示すようにプリフォーム10に入射する平行光線20のうち、光軸がプリフォーム10の中心軸に近い光線は、空気中からプリフォーム10に入射する際に屈折し、更に、貫通孔11との境界において屈折及び反射を繰り返し、殆ど前方に散乱されることなく損失する。その結果、プリフォーム10の前方散乱光の強度分布は、図3の上段に示すように、2つのピーク、及び、これら2つのピークに挟まれた暗部を有する強度分布になる。本明細書において「暗部幅」とは、これら2つのピークの間の距離のことを指す。
As shown in the lower part of FIG. 3, among the parallel rays 20 incident on the preform 10, rays whose optical axis is far from the central axis of the preform 10 are projected from the air as in the case where the through hole 11 is not formed. When entering the reform 10 and when entering the air from the preform 10, the light is refracted and reaches the opposite side of the preform 10. On the other hand, as shown in the lower part of FIG. 3, among the parallel light rays 20 incident on the preform 10, a light beam whose optical axis is close to the central axis of the preform 10 is refracted when entering the preform 10 from the air, Furthermore, refraction and reflection are repeated at the boundary with the through-hole 11, and the loss is made almost without being scattered forward. As a result, the intensity distribution of the forward scattered light of the preform 10 is an intensity distribution having two peaks and a dark part sandwiched between these two peaks, as shown in the upper part of FIG. In the present specification, the “dark width” refers to the distance between these two peaks.
図3の下段に示すようにプリフォーム10を一定の回転速度で回転させると、この暗部幅が周期的に変化する点に留意されたい。図3の下段に示すように貫通孔11がプリフォーム10の中心軸を中心とする正6角形の頂点上に配置されている場合、プリフォーム10の中心軸を通る、平行光線20に垂直な直線上に2つの貫通孔11が同時に配置されるときに暗部幅が最大値L0をとり、プリフォーム10の中心軸を通る、平行光線20に平行な直線上に2つの貫通孔11が同時に配置されるときに暗部幅が最小値をとる。図3の下段に示すようにプリフォーム10を回転させたときに得られる暗部幅の時系列をプロットすれば、図7に示すように、正弦波形が得られる。
It should be noted that when the preform 10 is rotated at a constant rotation speed as shown in the lower part of FIG. 3, the dark portion width periodically changes. As shown in the lower part of FIG. 3, when the through-hole 11 is arranged on the apex of a regular hexagon centering on the central axis of the preform 10, it passes through the central axis of the preform 10 and is perpendicular to the parallel light beam 20. When the two through-holes 11 are simultaneously arranged on the straight line, the dark part width takes the maximum value L 0 and the two through-holes 11 are simultaneously formed on the straight line passing through the central axis of the preform 10 and parallel to the parallel light beam 20. When placed, the dark space width takes the minimum value. If the time series of the dark part width obtained when the preform 10 is rotated as shown in the lower part of FIG. 3 is plotted, a sine waveform is obtained as shown in FIG.
なお、プリフォーム10を一定の回転速度で回転させたときに生じる暗部幅のこのような周期的な変化は、貫通孔11が偶数個の頂点を有する正多角形の頂点上に配置されている場合に一般的なものである。また、貫通孔が奇数個の頂点を有する正多角形の頂点上に配置されている場合であっても、暗部幅が特定の最大値及び最小値を有する点に変わりはない。
It should be noted that such a periodic change in the dark portion width that occurs when the preform 10 is rotated at a constant rotational speed is such that the through-hole 11 is disposed on the vertex of a regular polygon having an even number of vertices. It is a common case. Further, even when the through hole is arranged on the vertex of a regular polygon having an odd number of vertices, the dark portion width remains unchanged at a specific maximum value and minimum value.
図4の上段は、1つの貫通孔11aが位置ずれを起こしているプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布を示すグラフであり、図4の下段は、そのようなプリフォーム10の断面図である。前方散乱光の強度分布が2つのピーク、及び、これら2つのピークに挟まれた暗部を有する点は、図4の上段に示すように、貫通孔11が適正な位置に形成されている場合と同様である。
The upper part of FIG. 4 is a graph showing the intensity distribution of the forward scattered light obtained when the parallel light beam 20 is irradiated to the preform 10 in which one through hole 11a is displaced. The lower part of FIG. These are sectional views of such a preform 10. The point where the intensity distribution of the forward scattered light has two peaks and a dark part sandwiched between these two peaks is the case where the through hole 11 is formed at an appropriate position as shown in the upper part of FIG. It is the same.
図4の下段のプリフォーム10は、図3の下段のプリフォーム10とは異なり、1つの貫通孔11aが外側にずれて形成されている。このため、プリフォーム10の中心軸を通る、平行光線20に垂直な直線上に位置ずれを起こしている貫通孔11aが配置されるときに暗部幅が最大値L1をとる(L1>L0)。図4の下段に示すようにプリフォーム10を回転させたときに得られる暗部幅の時系列をプロットすると、図8に示すように崩れた波形となる。
The lower preform 10 in FIG. 4 is different from the lower preform 10 in FIG. 3 in that one through hole 11a is formed to be shifted outward. Therefore, passing through the central axis of the preform 10, the dark area width when the through-hole 11a that misaligned perpendicular straight line into parallel beams 20 are arranged to take the maximum value L 1 (L 1> L 0 ). When the time series of the dark part width obtained when the preform 10 is rotated as shown in the lower part of FIG. 4 is plotted, the waveform is broken as shown in FIG.
なお、貫通孔11aが内側にずれて形成されている場合には、位置ずれを起こしている貫通孔11aが、プリフォーム10の中心軸を通る、平行光線20に垂直な直線上に配置されるときの暗部幅が最大値に達しなくなる。
In addition, when the through hole 11 a is formed so as to be displaced inward, the through hole 11 a causing the positional displacement is arranged on a straight line that passes through the central axis of the preform 10 and is perpendicular to the parallel light beam 20. The dark part width at the time does not reach the maximum value.
図5の上段は、2つの貫通孔11a・bが位置ずれを起こしているプリフォーム10に対して平行光線を照射したときに得られる前方散乱光の強度分布を示すグラフであり、図5の下段は、そのようなプリフォーム10の断面図である。前方散乱光の強度分布が2つのピーク、及び、これら2つのピークに挟まれた暗部を有する強度分布になる点は、図5の上段に示すように、貫通孔11が適正な位置に形成されている場合と同様である。
The upper part of FIG. 5 is a graph showing the intensity distribution of forward scattered light obtained when the preform 10 in which the two through- holes 11a and 11b are displaced is irradiated with a parallel light beam. The lower part is a cross-sectional view of such a preform 10. As shown in the upper part of FIG. 5, the through hole 11 is formed at an appropriate position in that the intensity distribution of the forward scattered light has two peaks and an intensity distribution having a dark part sandwiched between these two peaks. It is the same as if
図5の下段のプリフォーム10は、図3の下段及び図4の下段のプリフォーム10とは異なり、中心軸を介して対向する2つの貫通孔11a・bが外側にずれて形成されている。このため、プリフォーム10の中心軸を通る、平行光線20に垂直な直線上に、位置ずれを起こしている2つの貫通孔11a・bが配置されるときに暗部幅が最大値L2をとる(L2>L1>L0)。図5の下段に示すようにプリフォーム10を回転させたときに得られる暗部幅の時系列をプロットすると、図9に示すように崩れた波形となる。
The lower preform 10 in FIG. 5 differs from the lower preform 10 in FIG. 3 and the lower preform 10 in FIG. 4 in that two through- holes 11 a and 11 b that are opposed to each other via the central axis are formed to be shifted outward. . Therefore, passing through the central axis of the preform 10, the vertical straight line into parallel beams 20, dark portion width when the two through holes 11a · b are misaligned is disposed a maximum value L 2 (L 2> L 1> L 0). When the time series of the dark part width obtained when the preform 10 is rotated as shown in the lower part of FIG. 5 is plotted, the waveform is broken as shown in FIG.
なお、貫通孔11a・bが内側にずれて形成されている場合にも、位置ずれを起こしている貫通孔11a・bが、プリフォーム10の中心軸を通る、平行光線20に垂直な直線上に配置されるときの暗部幅が最大値に達しなくなる。
Even when the through holes 11a and 11b are formed to be displaced inwardly, the through holes 11a and 11b that are misaligned are on a straight line that passes through the central axis of the preform 10 and is perpendicular to the parallel light beam 20. The dark portion width when placed in the position does not reach the maximum value.
〔貫通孔が適正な位置に形成されているか否かの暗部幅に基づく判定法〕
次に、貫通孔が予め定められた適正な位置に形成されているか否を、暗部幅の時系列に基づいて判定部106(図1参照)が判定する方法について、図6を参照して説明する。図6は、全ての貫通孔11が適正な位置に形成された理想的なプリフォーム10の断面図である。 [Judgment method based on whether or not the through-hole is formed at an appropriate position based on the dark width]
Next, a method for the determination unit 106 (see FIG. 1) to determine whether or not the through hole is formed at a predetermined appropriate position based on the time series of the dark part width will be described with reference to FIG. To do. FIG. 6 is a cross-sectional view of anideal preform 10 in which all through holes 11 are formed at appropriate positions.
次に、貫通孔が予め定められた適正な位置に形成されているか否を、暗部幅の時系列に基づいて判定部106(図1参照)が判定する方法について、図6を参照して説明する。図6は、全ての貫通孔11が適正な位置に形成された理想的なプリフォーム10の断面図である。 [Judgment method based on whether or not the through-hole is formed at an appropriate position based on the dark width]
Next, a method for the determination unit 106 (see FIG. 1) to determine whether or not the through hole is formed at a predetermined appropriate position based on the time series of the dark part width will be described with reference to FIG. To do. FIG. 6 is a cross-sectional view of an
上述したとおり、図6に示す理想的なプリフォーム10に形成された貫通孔11の何れか適正な位置から外側にずれると、そのプリフォーム10を1回転させたときに得られる暗部幅の時系列の最大値Lが、理想的なプリフォーム10を1回転させたときに得られる暗部幅の時系列の最大値L0よりも大きくなる。
As described above, when the through hole 11 formed in the ideal preform 10 shown in FIG. 6 deviates from an appropriate position to the outside, the dark portion width obtained when the preform 10 is rotated once. The maximum value L of the series becomes larger than the maximum value L 0 of the time series of the dark part width obtained when the ideal preform 10 is rotated once.
したがって、例えば、理想的なプリフォーム10を1回転させたときに得られる暗部幅の時系列の最大値L0よりも僅かに大きい値を閾値Thとして予め判定部106が備えるメモリに記憶しておくとともに、判定部106を、(1)演算部105にて算出された暗部幅の時系列の最大値Lを抽出し、(2)抽出した最大値Lを閾値Thと比較し、(3)抽出した最大値Lが閾値Thよりも大きいときに「貫通孔11が外側にずれている」と判定するように構成すれば、貫通孔11が適正な位置から外側にずれたことを検出可能な検査装置100を実現することができる。なお、理想的なプリフォーム10を1回転させたときに得られる暗部幅の時系列の最大値L0は、実測によって定めてもよいし、理想的なプリフォーム10において中心軸を介して対向する2つの貫通孔の中心間距離をD、貫通孔の孔径(直径)をdとして、式L0=D+dにより算出してもよい。
Therefore, for example, a value slightly larger than the time series maximum value L 0 of the dark part width obtained when the ideal preform 10 is rotated once is stored in advance in the memory included in the determination unit 106 as the threshold Th. In addition, the determination unit 106 extracts (1) the time series maximum value L of the dark part width calculated by the calculation unit 105, (2) compares the extracted maximum value L with the threshold Th, and (3) When the extracted maximum value L is larger than the threshold value Th, it is possible to detect that the through-hole 11 has shifted outward from an appropriate position by determining that the “through-hole 11 has shifted outward”. The inspection apparatus 100 can be realized. The time series maximum value L 0 of the dark part width obtained when the ideal preform 10 is rotated once may be determined by actual measurement or opposed to the ideal preform 10 via the central axis. the distance between the centers of the two through holes D, diameter of the through-holes (diameter) as d, may be calculated by the equation L 0 = D + d.
また、何れかの貫通孔11が適正な位置から内側にずれると、そのプリフォーム10を1回転させたときに得られる暗部幅の時系列に最大値L0に達しない極大値が現れる。したがって、例えば、理想的なプリフォーム10を1回転させたときに得られる暗部幅の時系列の最大値L0よりも僅かに小さい値を閾値Thとして予め判定部106が備えるメモリに記憶しておくとともに、判定部106を、(1)演算部105にて算出された暗部幅の時系列に含まれる全ての極大値を抽出し、(2)抽出した極大値の各々を閾値Thと比較し、(3)閾値Thよりも小さい極大値が存在したときに「貫通孔11が内側にずれている」と判定するように構成すれば、貫通孔11が適正な位置から内側にずれたことも検出可能な検査装置100を実現することができる。
Further, when any one of the through holes 11 is displaced inward from an appropriate position, a maximum value that does not reach the maximum value L 0 appears in the time series of the dark part width obtained when the preform 10 is rotated once. Therefore, for example, a value slightly smaller than the time series maximum value L 0 of the dark part width obtained when the ideal preform 10 is rotated once is stored in the memory included in the determination unit 106 in advance as the threshold Th. In addition, the determination unit 106 (1) extracts all the maximum values included in the time series of the dark portion width calculated by the calculation unit 105, and (2) compares each of the extracted maximum values with the threshold Th. (3) If it is determined that “the through hole 11 is displaced inward” when a maximum value smaller than the threshold Th is present, the through hole 11 may be displaced inward from an appropriate position. A detectable inspection apparatus 100 can be realized.
なお、ここでは、暗部幅の時系列が予め定められた閾値を超える最大値を有するときに貫通孔11が予め定められた位置に形成されていないと判定する判定方法について説明したが、本発明はこれに限定されるものではない。
Here, the determination method for determining that the through-hole 11 is not formed at a predetermined position when the time series of the dark part width has a maximum value exceeding a predetermined threshold has been described. Is not limited to this.
例えば、全ての貫通孔11が適正な位置にあれば、図7に示すように、暗部幅の時系列は正弦波形を示す。一方、貫通孔11が適正な位置からずれていれば、図8及び図9に示すように、崩れた波形となる。したがって、理想的なプリフォーム10を1回転させたときに得られる暗部幅の時系列の周波数スペクトル(1本の鋭いピークをもつ)を予め判定部106が備えるメモリに記憶しておき、これを演算部105にて算出された周波数スペクトルと比較することによっても、貫通孔が適正な位置に形成されているか否かを適切に判定することができる。
For example, if all the through holes 11 are at appropriate positions, the time series of the dark part width shows a sine waveform as shown in FIG. On the other hand, if the through hole 11 is deviated from an appropriate position, the waveform is broken as shown in FIGS. Therefore, the time-series frequency spectrum (with one sharp peak) of the dark part width obtained when the ideal preform 10 is rotated once is stored in advance in the memory provided in the determination unit 106. By comparing with the frequency spectrum calculated by the calculation unit 105, it can be appropriately determined whether or not the through hole is formed at an appropriate position.
〔まとめ〕
以上のように、本実施形態に係る検査装置は、貫通孔が形成された円柱状のプリフォームを検査する検査装置であって、上記プリフォームの側面から光線を入射させることにより生じた上記プリフォームの前方散乱光の強度分布を逐次検出する検出手段と、上記プリフォームの中心軸を回転軸として上記プリフォームを回転させるか、又は、上記プリフォームを周回するよう上記検出手段を移動させる回転/移動手段と、逐次検出された上記前方散乱光の強度分布から暗部幅の時系列を算出する算出手段と、を備えていることを特徴としている。 [Summary]
As described above, the inspection apparatus according to the present embodiment is an inspection apparatus that inspects a cylindrical preform having a through-hole formed therein, and the above-described profile generated by making a light beam incident from the side surface of the preform. Detection means for sequentially detecting the intensity distribution of the forward scattered light of the reform, and rotation for rotating the preform around the center axis of the preform or moving the detection means so as to go around the preform / Moving means, and calculating means for calculating a time series of the dark width from the intensity distribution of the forward scattered light detected sequentially.
以上のように、本実施形態に係る検査装置は、貫通孔が形成された円柱状のプリフォームを検査する検査装置であって、上記プリフォームの側面から光線を入射させることにより生じた上記プリフォームの前方散乱光の強度分布を逐次検出する検出手段と、上記プリフォームの中心軸を回転軸として上記プリフォームを回転させるか、又は、上記プリフォームを周回するよう上記検出手段を移動させる回転/移動手段と、逐次検出された上記前方散乱光の強度分布から暗部幅の時系列を算出する算出手段と、を備えていることを特徴としている。 [Summary]
As described above, the inspection apparatus according to the present embodiment is an inspection apparatus that inspects a cylindrical preform having a through-hole formed therein, and the above-described profile generated by making a light beam incident from the side surface of the preform. Detection means for sequentially detecting the intensity distribution of the forward scattered light of the reform, and rotation for rotating the preform around the center axis of the preform or moving the detection means so as to go around the preform / Moving means, and calculating means for calculating a time series of the dark width from the intensity distribution of the forward scattered light detected sequentially.
また、本実施形態に係る検査方法は、貫通孔が形成された円柱状のプリフォームを検査する検査方法であって、上記プリフォームの側面から光線を入射させることにより生じた上記プリフォームの前方散乱光の強度分布を検出手段によって逐次検出する検出工程と、上記プリフォームの中心軸を回転軸として上記プリフォームを回転させるか、又は、上記プリフォームを周回するよう上記検出手段を移動させる回転/移動工程と、逐次検出された上記前方散乱光の強度分布から暗部幅の時系列を算出する算出工程と、上記暗部幅の時系列に基づいて、上記貫通孔が予め定められた位置に形成されているか否かを判定する判定工程と、を含んでいる、ことを特徴としている。
Further, the inspection method according to the present embodiment is an inspection method for inspecting a cylindrical preform in which a through-hole is formed, and the front of the preform generated by allowing light to enter from a side surface of the preform. A detection step of sequentially detecting the intensity distribution of scattered light by a detection means, and a rotation for rotating the preform around the center axis of the preform or moving the detection means to go around the preform. / The moving step, the calculation step of calculating the time series of the dark part width from the intensity distribution of the forward scattered light sequentially detected, and the through hole is formed at a predetermined position based on the time series of the dark part width And a determination step of determining whether or not it has been performed.
上記の構成又は方法によれば、上記前方散乱光の強度分布に貫通孔の形成位置に応じた暗部が生じる。しかも、中心軸を回転軸として上記プリフォームを回転させるか、あるいは、上記プリフォームを周回するよう上記検出手段を移動させているので、上記前方散乱光の強度分布における暗部幅の時系列は、上記貫通孔が適正な位置に形成されているか否かによって異なる振る舞いをする。このため、上記の構成により算出される、上記前方散乱光の強度分布における暗部幅の時系列を参照すれば、上記貫通孔が予め定められた位置に形成されているか否かを上記プリフォームを破壊することなく精度よく確認することができるという効果を奏する。
According to the above configuration or method, a dark portion corresponding to the formation position of the through hole is generated in the intensity distribution of the forward scattered light. Moreover, since the preform is rotated with the central axis as the rotation axis, or the detection means is moved so as to go around the preform, the time series of the dark part width in the intensity distribution of the forward scattered light is: It behaves differently depending on whether or not the through hole is formed at an appropriate position. For this reason, referring to the time series of the dark portion width in the intensity distribution of the forward scattered light calculated by the above configuration, whether the through hole is formed at a predetermined position or not is determined as follows. There is an effect that it can be confirmed with high accuracy without destruction.
本実施形態に係る検査装置において、上記プリフォーム又は上記検出手段を上記プリフォームの中心軸方向に平行移動させる平行移動手段を更に備えていることが好ましい。
In the inspection apparatus according to this embodiment, it is preferable that the inspection apparatus further includes a translation unit that translates the preform or the detection unit in the central axis direction of the preform.
上記構成によれば、上記プリフォームの各断面について、上記貫通孔が予め定められた位置に形成されているか否かを上記プリフォームを破壊することなく精度よく確認することができるという更なる効果を奏する。
According to the above configuration, it is possible to accurately check whether or not the through hole is formed at a predetermined position for each cross section of the preform without destroying the preform. Play.
本実施形態に係る検査装置は、上記暗部幅の時系列の最大値又は極大値を予め定められた閾値と比較することによって、上記貫通孔が予め定められた位置に形成されているか否かを判定する判定手段を更に備えていることが好ましい。
The inspection apparatus according to this embodiment compares the time series maximum value or maximum value of the dark part width with a predetermined threshold value to determine whether the through hole is formed at a predetermined position. It is preferable to further comprise determination means for determining.
プリフォームに形成される貫通孔は、光ファイバに軸対称性をもたせるために、通常、プリフォームの中心軸を中心とする円周上に等間隔配置される。
The through holes formed in the preform are usually arranged at equal intervals on the circumference centered on the central axis of the preform in order to provide the optical fiber with axial symmetry.
この場合、貫通孔の何れかが円周上から外側にずれると、そのプリフォームを1回転させたときに得られる暗部幅の時系列の最大値が、全ての貫通孔が上記円周上に形成されたプリフォームを1回転させたときに得られる暗部幅の時系列の最大値よりも大きくなる。また、貫通孔の何れかが上記円周上から内側にずれると、そのプリフォームを1回転させたときに得られる暗部幅の時系列に、全ての貫通孔が上記円周上に形成されたプリフォームを1回転させたときに得られる暗部幅の時系列の最大値に達しない極大値が現れる。したがって、上記円周上に貫通孔が形成されたプリフォームを1回転させたときに得られる暗部幅の時系列の最大値を閾値として予め定めておけば、上記暗部幅の時系列の最大値をこの閾値と比較することによって、貫通孔が予め定められた位置に形成されているか否かを精度よく判定することができる。また、貫通孔の何れかが円周上から内側にずれた場合には、上記暗部の時系列の各極大値をこの閾値と比較することによって、貫通孔が予め定められた位置に形成されているか否かを精度よく判定することができる。
In this case, when any of the through holes is shifted from the circumference to the outside, the maximum value of the time series of the dark part width obtained when the preform is rotated once, all the through holes are on the circumference. It becomes larger than the time series maximum value of the dark part width obtained when the formed preform is rotated once. Further, when any of the through holes is displaced inward from the circumference, all the through holes are formed on the circumference in a time series of dark portion widths obtained when the preform is rotated once. A maximum value that does not reach the maximum value of the time series of the dark width obtained when the preform is rotated once appears. Accordingly, if the time series maximum value of the dark part width obtained when the preform having the through hole formed on the circumference is rotated once is set as a threshold value, the time series maximum value of the dark part width is determined. Can be accurately determined whether or not the through hole is formed at a predetermined position. Further, when any of the through holes is shifted inward from the circumference, the through hole is formed at a predetermined position by comparing each time series maximum value of the dark portion with this threshold value. It can be accurately determined whether or not there is.
本実施形態に係る検査装置は、上記暗部幅の時系列の周波数スペクトルを予め定められた周波数スペクトルと比較することによって、上記貫通孔が予め定められた位置に形成されているか否かを判定する判定手段を更に備えていることが好ましい。
The inspection apparatus according to the present embodiment determines whether or not the through hole is formed at a predetermined position by comparing the time-series frequency spectrum of the dark part width with a predetermined frequency spectrum. It is preferable to further comprise determination means.
プリフォームに形成される貫通孔は、光ファイバに軸対称性をもたせるために、通常、プリフォームの中心軸を中心とする円周上に等間隔配置される。この場合、上記暗部幅の時系列は正弦波形を示し、貫通孔に位置ずれが生じると、上記暗部幅の時系列は正弦波形が崩れたものとなる。したがって、上記暗部幅の時系列の周波数スペクトルを、貫通孔が円周上に等間隔配置されたプリフォームを1回転させたときに得られる暗部幅のスペクトルと比較することによって、貫通孔が円周上に等間隔配置されているか否かを精度良く判定することができるという効果を奏する。
The through holes formed in the preform are usually arranged at equal intervals on the circumference centered on the central axis of the preform in order to provide the optical fiber with axial symmetry. In this case, the time series of the dark part width shows a sine waveform, and when the position shift occurs in the through hole, the time series of the dark part width becomes a sine waveform collapsed. Therefore, by comparing the time-series frequency spectrum of the dark part width with the spectrum of the dark part width obtained when the preform having the through holes arranged at equal intervals on the circumference is rotated once, the through hole becomes circular. There is an effect that it can be accurately determined whether or not they are arranged at equal intervals on the circumference.
<第2の実施形態>
本発明の第2の実施形態(以下「本実施形態」と記載)について、図10~図14及び図16~図19を参照して説明する。本実施形態に係る検査装置は、プリフォームに形成された全ての貫通孔に生じた一様な位置ずれを検出するのに好適な検査装置である。 <Second Embodiment>
A second embodiment (hereinafter referred to as “this embodiment”) of the present invention will be described with reference to FIGS. 10 to 14 and FIGS. 16 to 19. The inspection apparatus according to the present embodiment is an inspection apparatus suitable for detecting a uniform positional deviation generated in all through holes formed in the preform.
本発明の第2の実施形態(以下「本実施形態」と記載)について、図10~図14及び図16~図19を参照して説明する。本実施形態に係る検査装置は、プリフォームに形成された全ての貫通孔に生じた一様な位置ずれを検出するのに好適な検査装置である。 <Second Embodiment>
A second embodiment (hereinafter referred to as “this embodiment”) of the present invention will be described with reference to FIGS. 10 to 14 and FIGS. 16 to 19. The inspection apparatus according to the present embodiment is an inspection apparatus suitable for detecting a uniform positional deviation generated in all through holes formed in the preform.
本実施形態において検出対象とする位置ずれの態様を図10に示す。図10の下段は、全ての貫通孔11’が一様な位置ずれを起こしているプリフォーム10の断面図であり、図10の上段は、そのようなプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布を示すグラフである。図10の上段に示すように、前方散乱光の強度分布が2つのピーク、及び、これら2つのピークに挟まれた暗部を有する点は、これまでに説明した場合と同様である。
FIG. 10 shows a mode of misalignment to be detected in this embodiment. The lower part of FIG. 10 is a cross-sectional view of the preform 10 in which all the through holes 11 ′ are uniformly displaced, and the upper part of FIG. 10 shows the parallel light beam 20 with respect to such a preform 10. It is a graph which shows intensity distribution of the forward scattered light obtained when it irradiates. As shown in the upper part of FIG. 10, the point that the intensity distribution of the forward scattered light has two peaks and a dark part sandwiched between these two peaks is the same as described above.
プリフォーム10に形成された全ての貫通孔11’が一様な位置ずれを起こしている場合、すなわち、プリフォーム10に形成された全ての貫通孔11’が、偏心した正6角形の頂点上に配置されている場合、プリフォーム10を一回転したときに得られる暗部幅Lの最大値は、理想的なプリフォーム10(図6参照)を1回転させたときに得られる暗部幅の最大値L0と一致してしまう。したがって、第1の実施形態に係る検査装置100では、プリフォーム10に形成された全ての貫通孔11’に生じた一様な位置ずれを検出することができない場合がある。
When all the through-holes 11 ′ formed in the preform 10 are uniformly displaced, that is, all the through-holes 11 ′ formed in the preform 10 are on the vertices of an eccentric regular hexagon. The maximum dark portion width L obtained when the preform 10 is rotated once is the maximum dark portion width obtained when the ideal preform 10 (see FIG. 6) is rotated once. It will match the value L 0. Therefore, the inspection apparatus 100 according to the first embodiment may not be able to detect a uniform positional deviation that has occurred in all the through holes 11 ′ formed in the preform 10.
そこで、本実施形態においては、前方散乱光の暗部の幅Lを参照する代わりに、(1)前方散乱光の強度を第1の明部上で積分して得られる積分値S1と、前方散乱光の強度を第2の明部上で積分して得られる積分値S2との差の絶対値(以下「積分値差」と略記する)ΔS=|S2-S1|を参照することによって、あるいは、(2)前方散乱光の第1の明部の幅(以下「第1の明部幅」と略記することもある)W1と、前方散乱光の第2の明部の幅(以下「第2の明部幅」と略記することもある)W2との差の絶対値(以下「明部幅差」と略記する)ΔW=|W2-W1|を参照することによって、プリフォーム10に形成された全ての貫通孔11’に生じた一様な位置ずれを検出する。
Therefore, in this embodiment, instead of referring to the dark portion width L of the forward scattered light, (1) the integrated value S1 obtained by integrating the intensity of the forward scattered light on the first bright portion, and the forward scattering By referring to the absolute value of the difference from the integrated value S2 obtained by integrating the light intensity on the second bright part (hereinafter abbreviated as “integrated value difference”) ΔS = | S2−S1 | (2) The width of the first bright portion of forward scattered light (hereinafter sometimes abbreviated as “first bright portion width”) W1 and the width of the second bright portion of forward scattered light (hereinafter referred to as “first”). 2 may be abbreviated as “bright part width”) (referred to as “bright part width difference”) ΔW = | W2−W1 | A uniform positional deviation generated in all the through-holes 11 'is detected.
ここで、前方散乱光の明部とは、図10に示すように、2つのピークの外側に広がる、前方散乱光の強度が予め定められた強度Ioよりも大きくなる領域のことを指す(説明の便宜上、暗部の左側に広がる明部を「第1の明部」と記載し、暗部の右側に広がる明部とを「第2の明部」と記載する)。なお、第1の明部の左端、及び、第2の明部の右端を規定する下限強度Ioは、0以上の任意の値に設定し得る。
Here, as shown in FIG. 10, the bright portion of the forward scattered light refers to a region where the intensity of the forward scattered light spreads outside the two peaks and becomes greater than a predetermined intensity Io (explanation). For the sake of convenience, the bright part spreading to the left of the dark part is referred to as “first bright part” and the bright part spreading to the right of the dark part is referred to as “second bright part”). The lower limit intensity Io that defines the left end of the first bright part and the right end of the second bright part can be set to an arbitrary value of 0 or more.
本実施形態に係る検査装置の構成は、図1に示す第1の実施形態に検査装置100の構成と同様である。ただし、積分値差ΔS=|S1-S2|を参照して検査を行う場合、演算部105が、検出器102により逐次検出された前方散乱光の強度分布から積分値差ΔS=|S1-S2|を逐次算出し、判定部106が、演算部105により逐次算出された積分値差ΔSの時系列に基づいて貫通孔11が適正な位置に形成されているか否かを判定する構成が採用される。一方、明部幅差ΔW=W2-W1を参照して検査を行う場合、演算部105が、検出器102により逐次検出された前方散乱光の強度分布から明部幅差ΔWを逐次算出し、判定部106が、演算部105により逐次算出された明部幅差ΔWの時系列に基づいて貫通孔11が適正な位置に形成されているか否かを判定する構成が採用される。
The configuration of the inspection apparatus according to this embodiment is the same as that of the inspection apparatus 100 in the first embodiment shown in FIG. However, when the inspection is performed with reference to the integral value difference ΔS = | S1-S2 |, the calculation unit 105 calculates the integral value difference ΔS = | S1-S2 from the intensity distribution of the forward scattered light sequentially detected by the detector 102. | Is sequentially calculated, and the determination unit 106 determines whether or not the through hole 11 is formed at an appropriate position based on the time series of the integral value difference ΔS sequentially calculated by the calculation unit 105. The On the other hand, when the inspection is performed with reference to the bright part width difference ΔW = W2−W1, the calculation unit 105 sequentially calculates the bright part width difference ΔW from the intensity distribution of the forward scattered light sequentially detected by the detector 102, A configuration is employed in which the determination unit 106 determines whether or not the through hole 11 is formed at an appropriate position based on the time series of the bright part width difference ΔW sequentially calculated by the calculation unit 105.
〔貫通孔が適正な位置に形成されているか否かの積分値差ΔSに基づく判定法〕
次に、貫通孔が適正な位置に形成されているか否を、判定部106が積分値差ΔSに基づいて判定する方法について、図11~図12および図16~図17を参照して説明する。 [Determination method based on integrated value difference ΔS as to whether or not the through hole is formed at an appropriate position]
Next, a method by which thedetermination unit 106 determines whether or not the through hole is formed at an appropriate position based on the integral value difference ΔS will be described with reference to FIGS. 11 to 12 and FIGS. 16 to 17. .
次に、貫通孔が適正な位置に形成されているか否を、判定部106が積分値差ΔSに基づいて判定する方法について、図11~図12および図16~図17を参照して説明する。 [Determination method based on integrated value difference ΔS as to whether or not the through hole is formed at an appropriate position]
Next, a method by which the
まず、適正な位置に貫通孔11が形成されているプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布について、図11を参照して説明する。図11の下段は、そのようなプリフォーム10の断面図であり、図11の上段は、そのようなプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布を示すグラフである。
First, the intensity distribution of the forward scattered light obtained when the preform 10 having the through holes 11 formed at appropriate positions is irradiated with the parallel light beam 20 will be described with reference to FIG. The lower part of FIG. 11 is a cross-sectional view of such a preform 10, and the upper part of FIG. 11 shows the intensity distribution of forward scattered light obtained when such a preform 10 is irradiated with parallel rays 20. It is a graph to show.
図11の上段においては、前方散乱光の強度を第1の明部上で積分して得られる積分値S1に対応する面積を有するグラフ上の領域、及び、前方散乱光の強度を第2の明部上で積分して得られる積分値S2に対応する面積を有するグラフ上の領域を、斜線を付すことによって明示している。
In the upper part of FIG. 11, the area on the graph having an area corresponding to the integrated value S1 obtained by integrating the intensity of the forward scattered light on the first bright portion, and the intensity of the forward scattered light are the second A region on the graph having an area corresponding to the integral value S2 obtained by integrating on the bright part is clearly indicated by hatching.
図11の下段に示すように、全ての貫通孔11が適正な位置に形成されている場合、図11の上段に示すように、前方散乱光の強度を第1の明部上で積分して得られる積分値S1と、前方散乱光の強度を第2の明部上で積分して得られる積分値S2とが概ね等しくなる。プリフォーム10を回転させても、これら2つの明部における前方散乱光の強度分布がプリフォーム10の中心軸に対して概ね対称に変化するので、積分値S1と積分値S2とは概ね等しい状態を保ち続ける。
As shown in the lower part of FIG. 11, when all the through holes 11 are formed at appropriate positions, the intensity of the forward scattered light is integrated on the first bright part as shown in the upper part of FIG. The obtained integrated value S1 and the integrated value S2 obtained by integrating the intensity of the forward scattered light on the second bright portion are substantially equal. Even if the preform 10 is rotated, the intensity distribution of the forward scattered light in these two bright portions changes substantially symmetrically with respect to the central axis of the preform 10, so that the integral value S1 and the integral value S2 are substantially equal. Keep on.
全ての貫通孔11が適正な位置に形成されているプリフォーム10を検査対象とした場合に、算出部105により算出される積分値差ΔS=|S2-S1|の時系列を図16に示す。算出部105により算出される積分値差ΔS=|S2-S1|の最大値が適宜設定した閾値ΔSoを超えていないことが、図16から見て取れる。
FIG. 16 shows a time series of the integral value difference ΔS = | S2−S1 | calculated by the calculation unit 105 when the preform 10 in which all the through holes 11 are formed at appropriate positions is an inspection target. . It can be seen from FIG. 16 that the maximum value of the integral value difference ΔS = | S2−S1 | calculated by the calculation unit 105 does not exceed the threshold value ΔSo set as appropriate.
次に、全ての貫通孔11’が一様に位置ずれを起こしているプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布について、図12を参照して説明する。図12の下段は、そのようなプリフォーム10の断面図であり、図12の上段は、そのようなリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布を示すグラフである。
Next, the intensity distribution of the forward scattered light obtained when the preform 10 in which all the through holes 11 ′ are uniformly displaced is irradiated with the parallel light beam 20 will be described with reference to FIG. 12. To do. The lower part of FIG. 12 is a cross-sectional view of such a preform 10, and the upper part of FIG. 12 shows the intensity distribution of forward scattered light obtained when such a reformer 10 is irradiated with parallel rays 20. It is a graph.
図12の上段においても、前方散乱光の強度を第1の明部上で積分して得られる積分値S1に対応する面積を有するグラフ上の領域、及び、前方散乱光の強度を第2の明部上で積分して得られる積分値S2に対応する面積を有するグラフ上の領域を、斜線を付すことによって明示している。
Also in the upper part of FIG. 12, the region on the graph having an area corresponding to the integrated value S1 obtained by integrating the intensity of the forward scattered light on the first bright portion, and the intensity of the forward scattered light are the second A region on the graph having an area corresponding to the integral value S2 obtained by integrating on the bright part is clearly indicated by hatching.
図12の下段に示すように、プリフォーム10の中心軸を通る、平行光線20に垂直な直線上に6つの貫通孔11’の重心(各頂点に貫通孔11’が配置された正6角形の中心)が配置されるときに、図12の上段に示す2つの積分値の差ΔS=|S2-S1|は極大値をとる。
As shown in the lower part of FIG. 12, the center of gravity of six through-holes 11 ′ passing through the central axis of the preform 10 and perpendicular to the parallel rays 20 (a regular hexagon in which the through-holes 11 ′ are arranged at each vertex) The difference ΔS = | S2−S1 | between the two integrated values shown in the upper part of FIG. 12 takes a maximum value.
全ての貫通孔11’が一様に位置ずれを起こしているプリフォーム10を検査対象とした場合に、算出部105により算出される積分値差ΔS=|S2-S1|の時系列を図17に示す。算出部105により算出される積分値差ΔS=|S2-S1|の各極大値が上述した閾値ΔSoを超えていることが、図17から見て取れる。
FIG. 17 shows a time series of the integral value difference ΔS = | S2−S1 | calculated by the calculation unit 105 when the preform 10 in which all the through holes 11 ′ are uniformly displaced is the inspection target. Shown in It can be seen from FIG. 17 that each maximum value of the integral value difference ΔS = | S2−S1 | calculated by the calculation unit 105 exceeds the threshold value ΔSo described above.
したがって、判定部106は、算出部105により算出される積分値差ΔS=|S2-S1|の各極大値を閾値ΔSoと比較することによって、貫通孔が適正な位置に形成されているか否かを判定することができる。具体的には、算出部105により算出される積分値差ΔS=|S2-S1|の各極大値が閾値Soを超えていない場合に、貫通孔が適正な位置に形成されていると判定し、算出部105により算出される積分値差ΔS=|S2-S1|の何れかが閾値Soを超えている場合に、貫通孔が適正な位置に形成されていない(位置ずれを起こしている)と判定すればよい。
Therefore, the determination unit 106 determines whether or not the through hole is formed at an appropriate position by comparing each local maximum value of the integral value difference ΔS = | S2−S1 | calculated by the calculation unit 105 with the threshold value ΔSo. Can be determined. Specifically, when each maximum value of the integral value difference ΔS = | S2−S1 | calculated by the calculation unit 105 does not exceed the threshold value So, it is determined that the through hole is formed at an appropriate position. When any one of the integral value differences ΔS = | S2−S1 | calculated by the calculation unit 105 exceeds the threshold value So, the through hole is not formed at an appropriate position (position displacement occurs). Can be determined.
〔貫通孔が適正な位置に形成されているか否かの、明部幅差ΔWに基づく判定法〕
次に、貫通孔が適正な位置に形成されているか否を、判定部106が明部幅差ΔWに基づいて判定する方法について、図13~図14および図18~図19を参照して説明する。 [Determination method based on the bright part width difference ΔW, whether or not the through hole is formed at an appropriate position]
Next, with reference to FIGS. 13 to 14 and FIGS. 18 to 19, a method for thedetermination unit 106 to determine whether or not the through hole is formed at an appropriate position based on the bright portion width difference ΔW will be described. To do.
次に、貫通孔が適正な位置に形成されているか否を、判定部106が明部幅差ΔWに基づいて判定する方法について、図13~図14および図18~図19を参照して説明する。 [Determination method based on the bright part width difference ΔW, whether or not the through hole is formed at an appropriate position]
Next, with reference to FIGS. 13 to 14 and FIGS. 18 to 19, a method for the
まず、適正な位置に貫通孔11が形成されているプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布について、図13を参照して説明する。図13の下段は、そのようなプリフォーム10の断面図であり、図13の上段は、そのようなプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布を示すグラフである。図13の上段においては、前方散乱光の第1の明部幅W1と第2の明部幅W2とを、それぞれ、矢印の長さにより明示している。
First, the intensity distribution of the forward scattered light obtained when the preform 10 having the through holes 11 formed at appropriate positions is irradiated with the parallel light beam 20 will be described with reference to FIG. The lower part of FIG. 13 is a sectional view of such a preform 10, and the upper part of FIG. 13 shows the intensity distribution of forward scattered light obtained when such a preform 10 is irradiated with parallel rays 20. It is a graph to show. In the upper part of FIG. 13, the first bright part width W1 and the second bright part width W2 of the forward scattered light are clearly shown by the lengths of the arrows.
図13の下段に示すように、全ての貫通孔11が適正な位置に形成されている場合、図13の上段に示すように、前方散乱光の第1の明部幅W1と第2の明部幅W2とが概ね等しくなる。プリフォーム10を回転させても、これら2つの明部における前方散乱光の強度分布がプリフォーム10の中心軸に対して概ね対称に変化するので、第1の明部幅W1と第2の明部幅W2とは概ね等しい状態を保ち続ける。
As shown in the lower part of FIG. 13, when all the through holes 11 are formed at appropriate positions, as shown in the upper part of FIG. 13, the first bright part width W1 and the second bright part of the forward scattered light are obtained. The part width W2 is substantially equal. Even if the preform 10 is rotated, the intensity distribution of the forward scattered light in these two bright portions changes substantially symmetrically with respect to the central axis of the preform 10, so that the first bright portion width W1 and the second bright portion are changed. The part width W2 is kept substantially equal.
全ての貫通孔11が適正な位置に形成されているプリフォーム10を検査対象とした場合に、算出部105により算出される明部幅差ΔW=|W1-W2|の時系列を図18に示す。算出部105により算出される明部幅差ΔW=|W1-W2|の最大値が適宜設定した閾値ΔWoを超えていないことが、図18から見て取れる。
FIG. 18 shows a time series of the bright part width difference ΔW = | W1−W2 | calculated by the calculation unit 105 when the preform 10 in which all the through holes 11 are formed at appropriate positions is an inspection target. Show. It can be seen from FIG. 18 that the maximum value of the bright part width difference ΔW = | W1−W2 | calculated by the calculation unit 105 does not exceed the threshold ΔWo set as appropriate.
次に、全ての貫通孔11’が一様に位置ずれを起こしているプリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布について、図14を参照して説明する。図14の下段は、そのようなプリフォーム10の断面図であり、図14の上段は、そのようなリフォーム10に対して平行光線20を照射したときに得られる前方散乱光の強度分布を示すグラフである。
Next, the intensity distribution of the forward scattered light obtained when the parallel light beam 20 is applied to the preform 10 in which all the through-holes 11 ′ are uniformly displaced will be described with reference to FIG. To do. The lower part of FIG. 14 is a cross-sectional view of such a preform 10, and the upper part of FIG. 14 shows the intensity distribution of forward scattered light obtained when such a reformer 10 is irradiated with parallel rays 20. It is a graph.
図14の下段に示すように、プリフォーム10の中心軸を通る、平行光線20に垂直な直線上に6つの貫通孔11’の重心(各頂点に貫通孔11’が配置された正6角形の中心)が配置されるときに、図14の上段に示す明部幅W1と明部幅W2との差ΔW=|W1-W2|は極大値をとる。
As shown in the lower part of FIG. 14, the center of gravity of six through-holes 11 ′ on a straight line that passes through the central axis of the preform 10 and is perpendicular to the parallel rays 20 (a regular hexagon in which the through-holes 11 ′ are arranged at each vertex) 14), the difference ΔW = | W1−W2 | between the bright portion width W1 and the bright portion width W2 shown in the upper part of FIG. 14 takes a local maximum value.
全ての貫通孔11’が一様に位置ずれを起こしているプリフォーム10を検査対象とした場合に、算出部105により算出される明部幅差ΔW=|W1-W2|の時系列を図19に示す。算出部105により算出される明部幅差ΔW=|W1-W2|の各極大値が上述した閾値ΔWoを超えていることが、図19から見て取れる。
When the preform 10 in which all the through-holes 11 ′ are uniformly displaced is set as the inspection target, the time series of the bright part width difference ΔW = | W1-W2 | calculated by the calculation unit 105 is illustrated. 19 shows. It can be seen from FIG. 19 that each maximum value of the bright part width difference ΔW = | W1−W2 | calculated by the calculation unit 105 exceeds the threshold value ΔWo.
したがって、判定部106は、算出部105により算出される明部幅差ΔW=|W1-W2|の各極大値を予め定めた閾値ΔWoと比較することによって、貫通孔が適正な位置に形成されているか否かを判定することができる。具体的には、算出部105により算出される明部幅差ΔW=|W1-W2|の各極大値が閾値Woを超えていないときに、貫通孔が適正な位置に形成されていると判定し、算出部105により算出される明部幅差ΔW=|W1-W2|の極大値の何れかが閾値ΔWoを超えているときに、貫通孔が適正な位置に形成されていない(位置ずれを起こしている)と判定すればよい。
Therefore, the determination unit 106 compares each local maximum value of the bright part width difference ΔW = | W1-W2 | calculated by the calculation unit 105 with a predetermined threshold value ΔWo, so that the through hole is formed at an appropriate position. It can be determined whether or not. Specifically, when each local maximum value of the bright part width difference ΔW = | W1−W2 | calculated by the calculation unit 105 does not exceed the threshold value Wo, it is determined that the through hole is formed at an appropriate position. When any one of the maximum values of the bright part width difference ΔW = | W1−W2 | calculated by the calculation unit 105 exceeds the threshold value ΔWo, the through hole is not formed at an appropriate position (position shift It is sufficient to determine that the
<付記事項>
本発明は上述した実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 <Additional notes>
The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims, and the technique of the present invention also relates to an embodiment obtained by appropriately combining the disclosed technical means. Included in the scope.
本発明は上述した実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 <Additional notes>
The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims, and the technique of the present invention also relates to an embodiment obtained by appropriately combining the disclosed technical means. Included in the scope.
上述した実施形態においては、貫通孔の位置ずれを検出するために利用する特徴量として、(1)前方散乱光の暗部幅、(2)前方散乱光の強度を2つの明部上で積分して得られる積分値の差の絶対値、(3)前方散乱光の2つの明部幅の差の絶対値を例示したが、貫通孔の位置ずれを検出するために利用可能な特徴量はこれに限定されるものではない。すなわち、前方散乱光の強度分布から算出することができ、かつ、プリフォームに形成された貫通孔の配置に応じた値を有する特徴量であれば、どのような特徴量であっても貫通孔の位置ずれを検出するために利用することができる。
In the embodiment described above, as feature quantities used for detecting the displacement of the through hole, (1) the dark part width of the forward scattered light and (2) the intensity of the forward scattered light are integrated on the two bright parts. (3) The absolute value of the difference between the two bright part widths of the forward scattered light is exemplified, but the feature quantity that can be used to detect the positional deviation of the through hole is It is not limited to. That is, any feature amount can be used as long as it is a feature amount that can be calculated from the intensity distribution of the forward scattered light and has a value corresponding to the arrangement of the through holes formed in the preform. It can be used to detect the positional deviation of
以下に実施例を示して、本発明の形態についてさらに詳しく説明する。もちろん、本発明は以下の実施例に限定されるものではなく、細部については様々な様態が可能である。
Hereinafter, examples of the present invention will be described in more detail with reference to examples. Of course, the present invention is not limited to the following examples, and various modes are possible for details.
〔実施例1〕
以下のようにして本発明の第1の実施形態に係る検査装置100の有効性について確認した。 [Example 1]
The effectiveness of theinspection apparatus 100 according to the first embodiment of the present invention was confirmed as follows.
以下のようにして本発明の第1の実施形態に係る検査装置100の有効性について確認した。 [Example 1]
The effectiveness of the
まず、図3の下段のような断面を長手方向の全体にわたって有するプリフォームAを作成した。具体的には、外径90mmφのプリフォームに対して、そのプリフォームの中心から20mmの位置に直径4mmφの6つの貫通孔をドリル法によって形成した。加えて、図4の下段のような断面を長手方向の全体にわたって有するプリフォームB、及び、図5の下段のような断面を長手方向の全体にわたって有するプリフォームCを、プリフォームAと同様の方法で作成した。ただし、プリフォームBの作成に際しては、1つの貫通孔(図4における貫通孔11a)を形成する位置を4mmだけ外側にずらし、プリフォームCの作成に際しては、2つの貫通孔(図5における貫通孔11aおよび貫通孔11b)の位置をそれぞれ4mmだけ外側にずらした。
First, a preform A having a cross section as shown in the lower part of FIG. Specifically, for a preform having an outer diameter of 90 mmφ, six through-holes having a diameter of 4 mmφ were formed by a drill method at a position 20 mm from the center of the preform. In addition, a preform B having a cross section as shown in the lower part of FIG. 4 in the entire longitudinal direction and a preform C having a cross section as shown in the lower part of FIG. Created by the method. However, when forming the preform B, the position where one through hole (through hole 11a in FIG. 4) is formed is shifted outward by 4 mm, and when forming the preform C, two through holes (through holes in FIG. 5) are formed. The positions of the holes 11a and the through holes 11b) were shifted outward by 4 mm respectively.
次に、検査装置100を用いてプリフォームAに関する暗部幅の時系列を得た。暗部幅の時系列の取得は、回転機構103に取り付けたプリフォームAを(プリフォームAの中心軸を回転軸として)回転させながら、かつ、平行移動機構104に取り付けた光源101及び検出器102をプリフォームAの中心軸に沿って平行移動させながら、前方散乱光の強度分布を検出器102にて検出することによって行った。この際、光源101及び検出器102としてLED及びCCDラインセンサを用いた。また、プリフォームの回転数を100rpmに、LED及びCCDラインセンサの移動速度を10mm/分に、CCDラインセンサにおけるサンプリング周期を500m秒にそれぞれ設定した。
Next, a time series of dark part widths related to the preform A was obtained using the inspection apparatus 100. The time-series acquisition of the dark part width is performed by rotating the preform A attached to the rotation mechanism 103 (with the central axis of the preform A as a rotation axis) and the light source 101 and the detector 102 attached to the parallel movement mechanism 104. Was detected by detecting the intensity distribution of the forward scattered light with the detector 102 while translating along the central axis of the preform A. At this time, LEDs and a CCD line sensor were used as the light source 101 and the detector 102. Further, the rotation speed of the preform was set to 100 rpm, the moving speed of the LED and the CCD line sensor was set to 10 mm / min, and the sampling period in the CCD line sensor was set to 500 milliseconds.
プリフォームAに関する暗部幅の時系列として、図7に示す正弦波形状の時系列が得られた。本実施例においては、この時系列を用いて、プリフォームB~Cの検査に用いる閾値Thの値を設定した。具体的には、この時系列における暗部幅の最大値をL0とし、閾値ThをL0よりも僅かに大きい値、具体的にはL0+0.5mmに設定した。なお、プリフォームAの作成に際して貫通孔を中心軸から20mmの位置に精度良く形成できる場合には、このように暗部幅の最大値Loを実測により求めることなく、40mmとしてしまっても構わない。
As a time series of dark portion widths related to the preform A, a time series having a sine wave shape shown in FIG. 7 was obtained. In this embodiment, the threshold value Th used for the inspection of the preforms B to C is set using this time series. Specifically, the maximum value of the dark space width in this time series is set to L 0 , and the threshold value Th is set to a value slightly larger than L 0 , specifically, L 0 +0.5 mm. If the through-hole can be accurately formed at a position 20 mm from the central axis at the time of forming the preform A, the maximum value Lo of the dark part width may be set to 40 mm without being obtained by actual measurement.
次に、第1の実施形態に係る検査装置100を用いて、プリフォームB~Cを検査した。検査は、暗部幅の実測時と同様、回転機構103に取り付けたプリフォームB~Cを(そのプリフォームの中心軸を回転軸として)回転させつつ、平行移動機構104に取り付けた光源101及び検出器102をプリフォームB~Cの中心軸に沿って平行移動させながら行った。この際、暗部幅の実測時と同様、光源101及び検出器102としてLED及びCCDラインセンサを用いた。また、暗部幅の実測時と同様、プリフォームの回転数を100rpmに、LED及びCCDラインセンサの移動速度を10mm/分に、CCDラインセンサにおけるサンプリング周期を500m秒にそれぞれ設定した。
Next, the preforms B to C were inspected using the inspection apparatus 100 according to the first embodiment. As in the actual measurement of the dark part width, the inspection is performed by rotating the preforms B to C attached to the rotating mechanism 103 (with the center axis of the preform as the rotating axis) and detecting the light source 101 attached to the parallel moving mechanism 104 and the detection. The vessel 102 was moved in parallel along the central axis of the preforms B to C. At this time, an LED and a CCD line sensor were used as the light source 101 and the detector 102, as in the actual measurement of the dark part width. Similarly to the actual measurement of the dark part width, the rotation speed of the preform was set to 100 rpm, the moving speed of the LED and the CCD line sensor was set to 10 mm / min, and the sampling period in the CCD line sensor was set to 500 milliseconds.
プリフォームBを検査対象としたときに演算部105によって算出された暗部幅の時系列は、図8に示すような波形を示した。この時系列における極大値は、いずれも、先に設定した閾値Thを超えていた。これは、1つの貫通孔が図4に示すように外側にずれて形成されているので、全ての貫通孔が適正な位置に形成されている場合よりも暗部幅の最大値が大きくなるためである。その結果、判定部106は、長手方向の全体にわたって「適正な位置から外側にずれた位置に貫通孔が形成されている」という判定を出力した。
The time series of the dark part width calculated by the arithmetic unit 105 when the preform B was the inspection target showed a waveform as shown in FIG. All the local maximum values in this time series exceeded the previously set threshold value Th. This is because one through hole is formed so as to be shifted outward as shown in FIG. 4, so that the maximum value of the dark part width is larger than when all the through holes are formed at appropriate positions. is there. As a result, the determination unit 106 outputs a determination that “a through-hole is formed at a position shifted outward from an appropriate position” over the entire longitudinal direction.
プリフォームCを検査対象としたときに演算部105によって算出された暗部幅の時系列は、図9に示すような波形を示した。この時系列における極大値は、いずれも、先に設定した閾値Thを超えていた。これは、2つの貫通孔が図5に示すように外側にずれて形成されているので、全ての貫通孔が適正な位置に形成されている場合よりも暗部幅の最大値が大きくなるためである。その結果、判定部106は、長手方向の全体にわたって「適正な位置から外側にずれた位置に貫通孔が形成されている」という判定を出力した。
The time series of the dark part width calculated by the arithmetic unit 105 when the preform C was the inspection target showed a waveform as shown in FIG. All the local maximum values in this time series exceeded the previously set threshold value Th. This is because the two through holes are formed so as to be shifted outward as shown in FIG. 5, so that the maximum value of the dark portion width is larger than when all the through holes are formed at appropriate positions. is there. As a result, the determination unit 106 outputs a determination that “a through-hole is formed at a position shifted outward from an appropriate position” over the entire longitudinal direction.
このようにして、第1の実施形態に係る検査装置100を用いることによって、プリフォームに形成された一部の貫通孔に生じた位置ずれを有効に検出することができることが確かめられた。
As described above, it was confirmed that by using the inspection apparatus 100 according to the first embodiment, it is possible to effectively detect the positional deviation generated in a part of the through holes formed in the preform.
〔実施例2〕
以下のようにして本発明の第2の実施形態に係る検査装置100の有効性について確認した。 [Example 2]
The effectiveness of theinspection apparatus 100 according to the second embodiment of the present invention was confirmed as follows.
以下のようにして本発明の第2の実施形態に係る検査装置100の有効性について確認した。 [Example 2]
The effectiveness of the
まず、図11の下段のような断面を長手方向の全体にわたって有するプリフォームを作成した。具体的には、外径90mmφのプリフォームに対して、プリフォームの中心から20mmの位置に直径4mmφの6つの貫通孔をドリル法によって形成した(このプリフォームは、実施例1で用いたプリフォームAと同じプリフォームなので、本実施例においてもプリフォームAと呼称する)。加えて、図15の下段のような断面を長手方向の全体にわたって有するプリフォームDを、プリフォームAと同様の方法で作成した。ただし、プリフォームDの作成に際しては、図15の下段に示すように、全ての貫通孔の形成位置を同一方向に3mmずらした。
First, a preform having a cross section as shown in the lower part of FIG. Specifically, for a preform having an outer diameter of 90 mmφ, six through-holes having a diameter of 4 mmφ were formed by a drill method at a position 20 mm from the center of the preform (this preform was formed by using the preform used in Example 1). Since it is the same preform as the reform A, it is also called the preform A in this embodiment). In addition, a preform D having a cross section as shown in the lower part of FIG. However, when forming the preform D, as shown in the lower part of FIG. 15, the formation positions of all the through holes were shifted by 3 mm in the same direction.
次に、積分値差ΔSに基づく判定法の有効性を以下のように確認した。なお、積分値差ΔSとは、上述したとおり、前方散乱光の強度を第1の明部上で積分して得られる積分値S1と、前方散乱光の強度を第2の明部上で積分して得られる積分値S2との差|S2-S1|のことを指す。また、第1の明部及び第2の明部とは、暗部の両側に広がる前方散乱光の強度が予め定められた強度Ioよりも大きくなる領域のことを指す。なお、本実施例においては、Io=0として第1の明部及び第2の明部を定めた。
Next, the effectiveness of the judgment method based on the integral value difference ΔS was confirmed as follows. Note that, as described above, the integral value difference ΔS is the integral value S1 obtained by integrating the intensity of the forward scattered light on the first bright part and the intensity of the forward scattered light on the second bright part. The difference | S2−S1 | from the integrated value S2 obtained in this way. The first bright part and the second bright part refer to a region where the intensity of forward scattered light spreading on both sides of the dark part is larger than a predetermined intensity Io. In the present embodiment, the first bright part and the second bright part are defined with Io = 0.
まず、検査装置100を用いてプリフォームAに関する積分値差ΔSの時系列を得た。積分値差ΔSの取得は、回転機構103に取り付けたプリフォームAを回転させながら、かつ、平行移動機構104に取り付けた光源101及び検出器102をプリフォームAの中心軸に沿って平行移動させながら、前方散乱光の強度分布を検出器102にて検出することによって行った。この際、光源101及び検出器102としてLED及びCCDラインセンサを用いた。また、プリフォームの回転数を100rpmに、LED及びCCDラインセンサの移動速度を10mm/分に、CCDラインセンサにおけるサンプリング周期を500m秒にそれぞれ設定した。
First, the time series of the integral value difference ΔS related to the preform A was obtained using the inspection apparatus 100. The integral value difference ΔS is obtained by rotating the preform A attached to the rotating mechanism 103 and moving the light source 101 and the detector 102 attached to the parallel moving mechanism 104 along the central axis of the preform A. However, the detection was performed by detecting the intensity distribution of the forward scattered light with the detector 102. At this time, LEDs and a CCD line sensor were used as the light source 101 and the detector 102. Further, the rotation speed of the preform was set to 100 rpm, the moving speed of the LED and the CCD line sensor was set to 10 mm / min, and the sampling period in the CCD line sensor was set to 500 milliseconds.
プリフォームAに関する積分値差ΔSの時系列として、図16に示す時系列が得られた。本実施例においては、この時系列を用いて、プリフォームDの検査に用いる閾値ΔSoの値を設定した。具体的には、この時系列における積分値差の最大値をΔSmaxとし、閾値ΔSoをΔSmaxよりも大きい値、具体的にはΔSmaxの3倍に設定した(図16に示すグラフの縦軸は面積の対数である)。
A time series shown in FIG. 16 was obtained as a time series of the integral value difference ΔS regarding the preform A. In this embodiment, the threshold value ΔSo used for the inspection of the preform D is set using this time series. Specifically, the maximum value of the integrated value difference in this time series is set to ΔS max , and the threshold value ΔS o is set to a value larger than ΔS max , specifically, three times ΔS max (see the graph shown in FIG. 16). The vertical axis is the logarithm of the area).
次に、検査装置100を用いてプリフォームDを検査した。検査は、プリフォームAに関する積分値差ΔSの実測時と同様、回転機構103に取り付けたプリフォームDを(プリフォームDの中心軸を回転軸として)回転させつつ、平行移動機構104に取り付けた光源101及び検出器102をプリフォームDの中心軸に沿って平行移動させながら行った。この際、プリフォームAに関する積分値差ΔSの実測時と同様、プリフォームの回転数を100rpmに、LED及びCCDラインセンサの移動速度を10mm/分に、CCDラインセンサにおけるサンプリング周期を500m秒にそれぞれ設定した。
Next, the preform D was inspected using the inspection apparatus 100. In the inspection, the preform D attached to the rotation mechanism 103 was rotated (with the central axis of the preform D as the rotation axis) and attached to the parallel movement mechanism 104, as in the actual measurement of the integral value difference ΔS related to the preform A. The light source 101 and the detector 102 were moved while being translated along the central axis of the preform D. At this time, the rotation speed of the preform is set to 100 rpm, the moving speed of the LED and the CCD line sensor is set to 10 mm / min, and the sampling period in the CCD line sensor is set to 500 milliseconds, as in the actual measurement of the integral value difference ΔS related to the preform A. Set each.
プリフォームDを検査対象としたときに演算部105によって算出された暗部幅の時系列は、図17に示す波形を有していた。この時系列における極大値は、いずれも、先に設定した閾値ΔSoを超えていた。その結果、判定部106は、長手方向の全体にわたって「貫通孔がずれている」という判定を出力した。
The time series of the dark part width calculated by the arithmetic unit 105 when the preform D is an inspection target has the waveform shown in FIG. All local maximum values in this time series exceeded the previously set threshold value ΔS o . As a result, the determination unit 106 outputs a determination that “the through hole is displaced” over the entire length direction.
次に、明部幅差ΔWに基づく判定法の有効性を以下のように確認した。明部幅差ΔWとは、上述したとおり、前方散乱光の第1の明部の幅W1と、前方散乱光の第2の明部の幅W2との差|W2-W1|のことを指す。また、第1の明部及び第2の明部とは、暗部の両側に広がる前方散乱光の強度が予め定められた強度Ioよりも大きくなる領域のことを指す。なお、本実施例においては、Io=0として第1の明部及び第2の明部を定めた。
Next, the effectiveness of the determination method based on the bright part width difference ΔW was confirmed as follows. The bright part width difference ΔW refers to the difference | W2−W1 | between the width W1 of the first bright part of the forward scattered light and the width W2 of the second bright part of the forward scattered light, as described above. . The first bright part and the second bright part refer to a region where the intensity of forward scattered light spreading on both sides of the dark part is larger than a predetermined intensity Io. In the present embodiment, the first bright part and the second bright part are defined with Io = 0.
まず、検査装置100を用いてプリフォームAに関する明部幅差ΔWの時系列を得た。明部幅差ΔWの取得は、回転機構103に取り付けたプリフォームAを回転させながら、かつ、平行移動機構104に取り付けた光源101及び検出器102をプリフォームAの中心軸に沿って平行移動させながら、前方散乱光の強度分布を検出器102にて検出することによって行った。この際、光源101及び検出器102としてLED及びCCDラインセンサを用いた。また、プリフォームの回転数を100rpmに、LED及びCCDラインセンサの移動速度を10mm/分に、CCDラインセンサにおけるサンプリング周期を500m秒にそれぞれ設定した。
First, the time series of the bright part width difference ΔW related to the preform A was obtained using the inspection apparatus 100. The bright part width difference ΔW is acquired by rotating the preform A attached to the rotating mechanism 103 and moving the light source 101 and the detector 102 attached to the parallel moving mechanism 104 along the central axis of the preform A. The intensity distribution of the forward scattered light was detected by the detector 102. At this time, LEDs and a CCD line sensor were used as the light source 101 and the detector 102. Further, the rotation speed of the preform was set to 100 rpm, the moving speed of the LED and the CCD line sensor was set to 10 mm / min, and the sampling period in the CCD line sensor was set to 500 milliseconds.
プリフォームAに関する明部幅差ΔWの時系列として、図18に示す時系列が得られた。本実施例においては、この時系列を用いて、プリフォームDの検査に用いる閾値ΔWoの値を設定した。具体的には、この時系列における明部幅差の最大値をΔWmaxとし、閾値ΔWoをΔWmaxよりも大きい値、具体的にはΔWmaxの3倍に設定した。
The time series shown in FIG. 18 was obtained as the time series of the bright part width difference ΔW related to the preform A. In this embodiment, the threshold ΔWo used for the inspection of the preform D is set using this time series. Specifically, the maximum value of the bright part width difference in this time series is set to ΔW max , and the threshold value ΔW o is set to a value larger than ΔW max , specifically, three times ΔW max .
次に、検査装置100を用いてプリフォームDを検査した。検査は、プリフォームAに関する明部幅差ΔWの実測時と同様、回転機構103に取り付けたプリフォームDを(プリフォームDの中心軸を回転軸として)回転させつつ、平行移動機構104に取り付けた光源101及び検出器102をプリフォームDの中心軸に沿って平行移動させながら行った。この際、プリフォームAに関する明部幅差ΔWの実測時と同様、プリフォームの回転数を100rpmに、LED及びCCDラインセンサの移動速度を10mm/分に、CCDラインセンサにおけるサンプリング周期を500m秒にそれぞれ設定した。
Next, the preform D was inspected using the inspection apparatus 100. As in the case of the actual measurement of the bright part width difference ΔW related to the preform A, the inspection is attached to the parallel movement mechanism 104 while rotating the preform D attached to the rotation mechanism 103 (with the central axis of the preform D as the rotation axis). The light source 101 and the detector 102 were moved while being translated along the center axis of the preform D. At this time, as in the actual measurement of the bright part width difference ΔW related to the preform A, the rotation speed of the preform is set to 100 rpm, the moving speed of the LED and the CCD line sensor is set to 10 mm / min, and the sampling period in the CCD line sensor is set to 500 milliseconds. Respectively.
プリフォームDを検査対象としたときに演算部105によって算出された明部幅差ΔWの時系列は、図19に示すような波形を示した。この時系列における極大値は、いずれも、先に設定した閾値ΔWoを超えていた。その結果、判定部106は、長手方向の全体にわたって「貫通孔がずれている」という判定を出力した。
The time series of the bright part width difference ΔW calculated by the calculation unit 105 when the preform D is an inspection target has a waveform as shown in FIG. All local maximum values in this time series exceeded the previously set threshold value ΔW o . As a result, the determination unit 106 outputs a determination that “the through hole is displaced” over the entire length direction.
このようにして、第2の実施形態に係る検査装置100を用いることによって、プリフォームに形成された全ての貫通孔に生じた一様な位置ずれを有効に検出することができることが確かめられた。
In this way, it was confirmed that uniform positional deviation generated in all the through holes formed in the preform can be effectively detected by using the inspection apparatus 100 according to the second embodiment. .
本発明に係る検査方法は、フォトニック結晶ファイバなど、空孔が形成された光ファイバの母材となるプリフォームの検査に好適に利用することができる。
The inspection method according to the present invention can be suitably used for inspection of a preform that is a base material of an optical fiber in which holes are formed, such as a photonic crystal fiber.
10 プリフォーム
10’ プリフォーム
11 貫通孔
20 平行光線
101 光源
102 検出器(検出手段)
103 回転機構(回転/移動手段)
104 平行移動機構(平行移動手段)
105 演算部(算出手段)
106 判定部
107 位置検出部
DESCRIPTION OFSYMBOLS 10 Preform 10 'Preform 11 Through-hole 20 Parallel light beam 101 Light source 102 Detector (detection means)
103 Rotating mechanism (rotating / moving means)
104 Translation mechanism (parallel translation means)
105 Calculation unit (calculation means)
106determination unit 107 position detection unit
10’ プリフォーム
11 貫通孔
20 平行光線
101 光源
102 検出器(検出手段)
103 回転機構(回転/移動手段)
104 平行移動機構(平行移動手段)
105 演算部(算出手段)
106 判定部
107 位置検出部
DESCRIPTION OF
103 Rotating mechanism (rotating / moving means)
104 Translation mechanism (parallel translation means)
105 Calculation unit (calculation means)
106
Claims (8)
- 貫通孔が形成された円柱状のプリフォームを検査する検査装置であって、
上記プリフォームの側面から光線を入射させることにより生じた上記プリフォームの前方散乱光の強度分布を逐次検出する検出手段と、
上記プリフォームの中心軸を回転軸として上記プリフォームを回転させるか、又は、上記プリフォームを周回するよう上記検出手段を移動させる回転/移動手段と、
逐次検出された上記前方散乱光の強度分布から、上記貫通孔の配置に応じた値をもつ特徴量の時系列を算出する算出手段とを備えている、ことを特徴とする検査装置。 An inspection device for inspecting a cylindrical preform having a through-hole formed therein,
Detection means for sequentially detecting the intensity distribution of the forward scattered light of the preform produced by the incidence of light from the side surface of the preform;
Rotating / moving means for rotating the preform around the center axis of the preform or moving the detecting means to go around the preform;
An inspection apparatus, comprising: a calculating unit that calculates a time series of feature amounts having a value corresponding to the arrangement of the through holes from the intensity distribution of the forward scattered light detected sequentially. - 上記特徴量は、上記前方散乱光の暗部幅である、
ことを特徴とする請求項1に記載の検査装置。 The feature amount is a dark width of the forward scattered light.
The inspection apparatus according to claim 1. - 上記特徴量は、上記前方散乱光の2つのピークの外側に広がる、上記前方散乱光の強度が予め定められた強度よりも大きくなる2つの領域を明部として、上記前方散乱光の強度をこれら2つの明部上で積分して得られる積分値の差の絶対値である、ことを特徴とする請求項1に記載の検査装置。 The feature amount includes the two regions where the intensity of the forward scattered light, which spreads outside the two peaks of the forward scattered light, becomes larger than a predetermined intensity, and the intensity of the forward scattered light as these areas. The inspection apparatus according to claim 1, wherein the inspection apparatus is an absolute value of a difference between integral values obtained by integration on two bright portions.
- 上記特徴量は、上記前方散乱光の2つのピークの外側に広がる、上記前方散乱光の強度が予め定められた強度よりも大きくなる2つの領域を明部として、これら2つの明部の幅の差の絶対値である、ことを特徴とする請求項1に記載の検査装置。 The feature amount is defined as two regions where the intensity of the forward scattered light is larger than a predetermined intensity and spreads outside the two peaks of the forward scattered light. The inspection apparatus according to claim 1, wherein the inspection apparatus is an absolute value of the difference.
- 上記特徴量の時系列の最大値又は極大値を予め定められた閾値と比較することによって、上記貫通孔が予め定められた位置に形成されているか否かを判定する判定手段を更に備えている、ことを特徴とする請求項2から4までの何れか1項に記載の検査装置。 The apparatus further includes a determination unit that determines whether or not the through hole is formed at a predetermined position by comparing the time-series maximum value or local maximum value of the feature amount with a predetermined threshold value. 5. The inspection apparatus according to any one of claims 2 to 4, wherein:
- 上記暗部幅の時系列の周波数スペクトルを予め定められた周波数スペクトルと比較することによって、上記貫通孔が予め定められた位置に形成されているか否かを判定する判定手段を更に備えている、ことを特徴とする請求項2に記載の検査装置。 It further comprises determination means for determining whether or not the through hole is formed at a predetermined position by comparing the time-series frequency spectrum of the dark space width with a predetermined frequency spectrum. The inspection apparatus according to claim 2.
- 上記プリフォーム又は上記検出手段を上記プリフォームの中心軸方向に平行移動させる平行移動手段を更に備えている、ことを特徴とする請求項1から6までの何れか1項に記載の検査装置。 The inspection apparatus according to any one of claims 1 to 6, further comprising translation means for translating the preform or the detection means in the central axis direction of the preform.
- 貫通孔が形成された円柱状のプリフォームを検査する検査方法であって、
上記プリフォームの側面から光線を入射させることにより生じた上記プリフォームの前方散乱光の強度分布を検出手段によって逐次検出する検出工程と、
上記プリフォームの中心軸を回転軸として上記プリフォームを回転させるか、又は、上記プリフォームを周回するよう上記検出手段を移動させる回転/移動工程と、
逐次検出された上記前方散乱光の強度分布から、上記貫通孔の配置に応じた値をもつ特徴量の時系列を算出する算出工程と、
上記特徴量の時系列に基づいて、上記貫通孔が予め定められた位置に形成されているか否かを判定する判定工程とを含んでいる、ことを特徴とする検査方法。 An inspection method for inspecting a cylindrical preform in which a through hole is formed,
A detection step of sequentially detecting the intensity distribution of the forward scattered light of the preform generated by the incidence of light from the side surface of the preform by a detection unit;
Rotating / moving step of rotating the preform around the center axis of the preform or moving the detection means to go around the preform;
From the intensity distribution of the forward scattered light detected sequentially, a calculation step of calculating a time series of feature values having values according to the arrangement of the through holes,
And a determination step of determining whether or not the through hole is formed at a predetermined position based on a time series of the feature amount.
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