JP7128063B2 - Optical waveguide processing method and cutting tool - Google Patents

Description

The present invention relates to an optical waveguide processing method and a cutting tool for processing an optical waveguide.

An optical waveguide is an optical transmission line that includes a core that serves as an optical path and a clad that surrounds the core. As a device using an optical waveguide, for example, there is a sensor cell described in Patent Document 1, which utilizes SPR (Surface Plasmon Resonance), which is an optical phenomenon. The optical waveguide used in the sensor cell is characterized in that the core on the upper surface of the optical waveguide is exposed. Moreover, a sensor described in Patent Document 2 has also been developed, in which a plurality of exposed surfaces are extended in a winding shape to increase detection sensitivity. There is also a laminated optical circuit described in Patent Document 3, which contributes to an improvement in the integration density of an optical circuit by laminating a plurality of optical waveguides having such characteristics in the thickness direction.

In order to manufacture such a sensor cell or the like, as a pre-process, the clad on the top surface of the optical waveguide is removed by machining such as grinding or polishing from the state in which the core of the optical waveguide is embedded in the clad, and the top surface of the core is removed. Processing to expose is required.

JP 2015-081775 A JP 2011-232574 A Japanese Patent Application Publication No. 2011-070107

Regarding the above processing, since the amount of removal is generally set based on the upper and lower surfaces (holding surfaces) of the workpiece in machining by machine, there is variation in the thickness of the clad below the core and the clad above the core. , the core may not be exposed even if it is processed based on the design values. Therefore, after processing, it is necessary to separately confirm that the core is definitely exposed, and this confirmation takes time. Since both the core and the clad are generally made of transparent resin, there is a problem that it is difficult to confirm from the appearance that the core is exposed.

The present invention is a method of processing an optical waveguide in which a rod-shaped core having one end and the other end is embedded in a clad and disposed on a support member, the core having at least one end or the other end a cutting step of forming a cut surface by cutting the upper surface of the optical waveguide with a cutting tool blade positioned at a predetermined height position by holding the supporting member on a holding table; After performing the step, light is incident from the exposed one end or the other end of the core, and confirmation is made based on the light emitted from the cutting surface to confirm whether the core is exposed to the cutting surface. and an additional cutting step of positioning the tool cutting edge at a position lower than the predetermined height position to cut the upper surface of the optical waveguide when the core is not exposed on the cut surface in the confirmation step. and have. The present invention also provides the above optical waveguide processing method, wherein the optical waveguide having the core completely embedded in the cladding is subjected to cutting of the one end or the other before performing the cutting step. The optical waveguide processing method further includes an exposing step of exposing one end. Further, in one of the two optical waveguide processing methods described above, a plurality of cores are disposed on the support member in a state of being embedded in the clad, and the confirming step includes: The optical waveguide processing method includes checking whether or not all the cores are exposed on the cut surface, and performing the additional cutting step when all the cores are not exposed.

Further, the present invention provides a holding table for holding the supporting member of the optical waveguide arranged on the supporting member with a rod-shaped core having one end and the other end embedded in the clad, and the holding table. and a tool cutting means having a tool cutting edge for cutting a held optical waveguide, the cutting tool cutting toward the exposed one end or the other end of the core held by the holding table. The cutting tool includes light projecting means for projecting light and imaging means for imaging the upper surface of the optical waveguide substrate held by the holding table.

In the processing method of the present invention, by projecting light onto one end or the other end of the exposed core, the core is projected onto the cut surface based on the light emitted from the cut surface formed by cutting the upper surface of the optical waveguide. It can be easily confirmed whether or not it is exposed. This makes it possible to efficiently form an optical waveguide in which the upper surface of the core is exposed.

FIG. 4 is a perspective view showing an optical waveguide with a core exposed from the side; FIG. 3 is a perspective view showing an optical waveguide in which the core is completely buried by the cladding; It is a perspective view showing a cutting tool cutting device. It is explanatory drawing showing the mode of thickness measurement. It is explanatory drawing showing a mode that the exposure of a core is confirmed. FIG. 5 is an explanatory diagram showing a state in which a support member is held by suction on a holding table; It is explanatory drawing showing the mode of cutting. It is explanatory drawing showing the mode of cutting. It is a top view showing the appearance of the optical waveguide upper surface imaged by the imaging means. It is explanatory drawing showing the mode of additional cutting. It is a top view showing a mode that all the cores of the optical waveguide upper surface are exposed. FIG. 3 is an explanatory diagram showing a planned cutting position; It is an explanatory view showing cutting by a blade. It is explanatory drawing showing a mode that light is projected to a cutting groove and exposure of a core is confirmed.

1. Structure of Optical Waveguide As shown in FIGS. 1 and 2, an optical waveguide O to be machined by carrying out the present invention includes a rod-shaped core C2 having one end and the other end embedded in a clad C1 and a supporting member. Located on S. The support member S may be, for example, a hard substrate such as glass, silicon, or resin, or may be a tape. The upper surface of the clad C1 of the optical waveguide O is the surface to be cut. 1 shows a state in which one end or the other end of the core C2 is exposed on the side surface of the optical waveguide O, but as shown in FIG. sometimes not. The embodiment of the cutting process of the present invention differs depending on whether one end or the other end of the core C2 is exposed on the side surface of the optical waveguide O, and each case will be described separately. In the following, when the optical waveguide O and the support member S are integrated and shown in motion, they are referred to as a unit U.

2. Configuration of Tool Cutting Device A tool cutting device 1 shown in FIG. It is a device that The front (−Y direction side) on the base 10 of the cutting tool 1 is an area for attaching and detaching the support member S to/from the holding table 30, and the rear (+Y direction side) on the base 10 is for cutting the cutting tool. The upper surface of the optical waveguide O held on the holding table 30 via the support member S by the means 6 is a region for cutting.

On the front side of the base 10 of the processing apparatus 1, input means 20 for inputting processing conditions and the like by the operator is arranged. Further, on the front side of the base 10, a first cassette 331 containing units U before cutting and a second cassette 332 containing units U after cutting are arranged. A robot 330 is arranged between the first cassette 331 and the second cassette 332 to unload the unit U before cutting from the first cassette 331 and to load the unit U after cutting into the cassette 332 . is set.

A temporary placement table 333a for temporarily placing the unit U before processing is provided in the movable range of the robot 330, and an alignment means 333b is arranged on the temporary placement table 333a. The alignment means 333b aligns the unit U unloaded from the first cassette 331 and placed on the temporary placement table 333a at a predetermined position by means of a plurality of alignment pins that move in a diameter-reducing direction. In addition, cleaning means 334 for cleaning the processed unit U is arranged in the movable range of the robot 330 . The cleaning means 334 is, for example, a single-wafer type spinner cleaning device.

A first conveying means 335 is arranged near the alignment means 333 b and a second conveying means 336 is arranged near the cleaning means 334 . The first transport means 335 transports the pre-cutting unit U placed and aligned on the temporary placement table 333 a to the holding table 30 , and the second transport means 336 transports the cutting unit held on the holding table 30 . The processed unit U is transported to the cleaning means 334 .

The holding table 30 sucks and holds the support member S from below by suction means (not shown) covered with a cover 39 located below the holding table 30 . Y-axis moving means (not shown) for moving both the cover 39 and the holding table 30 in the Y-axis direction is provided in the area covered by the lower surface of the holding table 30, the cover 39, and the bellows cover 39a connected to the cover 39. are arranged. The bellows cover 39a expands and contracts in the Y-axis direction as the holding table 30 moves.

A column 11 is erected on the rear side (+Y direction side) of the base 10 . On the front surface of the column 11 , the tool cutting means 6 is raised and lowered in the Z-axis direction (vertical direction), A processing feed means 5 is provided for separating or approaching. The processing feed means 5 includes a ball screw 50 having an axis in the Z-axis direction, a pair of guide rails 51 arranged parallel to the ball screw 50, and a motor 52 connected to the upper end of the ball screw 50 and rotating the ball screw 50. , a lifting plate 53 having an internal nut screwed onto the ball screw 50 and having a side portion in sliding contact with the guide rail 51; As the hoist 50 is rotated, the elevating plate 53 is guided by the guide rail 51 to reciprocate in the Z-axis direction, and the turning tool 6 held by the holder 54 is fed in the Z-axis direction.

The cutting tool 6 includes a spindle 60 whose axial direction is vertical (the Z-axis direction), a housing 61 that rotatably supports the spindle 60, a motor 62 that drives the spindle 60, and a lower end of the spindle 60. and a circular bite wheel 63 and a bite tool 64 detachably attached to the bite wheel 63.

A bite tool 64 is inserted into the bite wheel 63, and the bite tool 64 has a cutting edge 64a. The cutting edge 64a is, for example, single crystal diamond, CBN, or the like.

On the base 10, a recessed portion surrounded by a wall portion 100 and a column 11 is formed. The wash water containing portion 101 receives the wash water flowing down from the holding table 30 . A drain port 102 is formed in the cleaning water storage unit 101, and the cleaning water containing cutting chips and the like is drained from the drain port 102 to a drain tank (not shown) or the like.

Above the movement path of the holding table 30, a contact thickness gauge 17 and a non-contact thickness gauge 18 for measuring the thickness of the cut optical waveguide O are arranged. Both are supported by a support bridge 19 constructed on the base 10 so as to straddle the holding table 30, and are reciprocally movable in the X-axis direction, for example. The contact thickness gauge 17 is a linear gauge that can move in the Z-axis direction, while the non-contact thickness gauge 18 has a light emitter and a light receiver and uses a laser to measure the thickness of the optical waveguide O. It is a non-contact type thickness gauge. As shown in FIG. 4, the contact-type thickness measuring instrument 17 measures the thickness by bringing the tip of the contactor of the thickness gauge 170a and the tip of the contactor of the thickness gauge 170b into contact with the upper surface of the support member S and the upper surface of the optical waveguide O, respectively. to measure. In measuring the thickness, the upper surface of the optical waveguide O is measured at a plurality of points, and the maximum value is taken as the position of the upper surface of the optical waveguide O, for example. Alternatively, an average value calculated from measurements at a plurality of points may be used as the upper surface position of the optical waveguide O. FIG.

As shown in FIG. 3, similarly, above the moving path of the holding table 30, the light projecting means 15 and the imaging means 16 supported by the supporting bridge 19 are arranged. As shown in FIG. 5, the light projecting means 15 includes a light projecting unit 150, a cylinder 151, and a light emitting portion 152. As shown in FIG. By controlling the light projecting unit 150, the cylinder 151 connected to the light projecting unit 150 can be moved up and down, and the light emitting part 152 connected to the cylinder 151 can be moved up and down in the ±Z directions. Furthermore, by controlling the light projection unit 150, the orientation of the light emitting section 152 can be changed to adjust the projection direction. The imaging means 16 is directed to the upper surface of the optical waveguide O, and images the upper surface of the optical waveguide O while the light projecting means 15 is projecting light. Depending on whether or not the core C2 shown in FIGS. 1 and 2 is exposed on the top surface of the optical waveguide O, the state of the top surface of the optical waveguide O captured differs, and based on this, whether the core C2 is exposed or not. to confirm.

3. Processing Method A method of processing the optical waveguide O using the cutting tool 1 will be described below with reference to FIGS. 1 to 10. FIG. At that time, the case will be divided according to whether or not one end or the other end of the core C2 is already exposed on the side surface of the optical waveguide O, and the explanation will be made. As shown in FIG. 1, the embodiment in which one end or the other end of the core C2 is exposed on the side surface of the optical waveguide O is the "first embodiment", and as shown in FIG. An embodiment in the case of being completely embedded inside C1 is referred to as a "second embodiment".

[First embodiment]
When one end or the other end of the core C2 is exposed on the side surface of the optical waveguide as in FIG. 1, the embodiment of the present invention comprises a cutting step, a confirmation step and an additional cutting step.

(cutting step)
(1) Holding As shown in FIG. 3, the unit U before cutting is sent by the robot 330 from the first cassette 331 to the temporary placement table 333a. Further, the unit U is aligned by the alignment means 333 b and transported to the holding table 30 by the first transport means 335 . As shown in FIG. 6, the transported unit U is fixed by sucking the lower surface of the support member S from below by a suction means (not shown) positioned below the holding table 30 .

(2) Thickness measurement As shown in FIG. Measure the thickness. As shown in FIG. 4, the tip of the contact of the thickness gauge 170a and the tip of the contact of the thickness gauge 170b are brought into contact with the upper surface of the support member S and the upper surface of the clad C1, respectively, and the height of the two contacts is adjusted. The thickness difference is measured as the thickness of the optical waveguide O.

(3) Cutting For example, the Y-axis moving means (not shown) located below the holding table 30 shown in FIG. , the holding table 30 is positioned at the starting position of the cutting feed. Then, by feeding the tool cutting means 6 by a predetermined length in the -Z direction by the processing feed means 5, the tool cutting edge 64a is positioned at a position for cutting by a predetermined amount. Further, the motor 62 rotates the spindle 60 having an axis in the Z-axis direction at a predetermined rotational speed, and accordingly the cutting tool 64 rotates around the spindle 60 at a predetermined rotational speed. Next, the holding table 30 sucking and holding the support member S is moved in the -Y direction at a predetermined feed rate, and the cutting edge 64a cuts the upper surface of the optical waveguide O to expose the core C2. 7 and 8 show how cutting is performed. For example, if the upper and lower cladding layers C1 of the core C2 are each 10 μm thick, first, as shown in FIG. After positioning and cutting with the tool, as shown in FIG. 8, the tip of the tool cutting edge 64a is further positioned at a position lowered by 5 μm and cut again to expose the upper surface of the core C2.

(confirmation step)
After performing the cutting step, it is confirmed whether the core C2 on the upper surface of the optical waveguide O is exposed. As shown in FIG. 5, the light emitting unit 150 is controlled so that the height of the light emitting part 152 and the light emitting part 152 are adjusted so that the light from the light emitting part 152 is incident on one end or the other end of the core C2 exposed on the side surface of the optical waveguide O. is adjusted, and the light is projected from the light emitting portion 152 . The projected light enters the core C2 from one end or the other end of the core C2 exposed on the side surface of the optical waveguide O, and passes through the core C2. At this time, if the upper surface of the core C2 is exposed by cutting in the cutting step, the incident light is emitted from the cut surface Oa to the outside of the optical waveguide O, but the upper surface of the core C2 is also exposed by cutting. If not, the light would not be emitted to the outside of the optical waveguide O from the cut surface Oa. This state is imaged from above the cutting surface Oa by the imaging means 16 while the light projecting means 15 is projecting light. If the upper surface of the core C2 is exposed, the cutting surface Oa imaged by the imaging means 16 will appear bright due to the light emitted from the core C2. Since no light is emitted, it looks relatively darker than when the top surface of core C2 is exposed. The operator can determine whether the top surface of the core C2 is exposed by analyzing the photographed cut surface Oa using, for example, image analysis software.

(re-cutting step)
If the core C2 is not exposed on the cutting surface Oa as a result of confirmation by the confirmation step, the cutting tool blade 64a is positioned at a position lower than the predetermined height position to cut the upper surface of the optical waveguide O again. When a plurality of cores C2 are embedded in the clad C1 and there are cores C2 that are not exposed on the cutting surface Oa as shown in FIG. Cutting by the cutting means 6 and confirmation by the imaging means 16 are repeated. As shown in FIG. 10, in the additional cutting step, it is preferable to cut with a smaller depth of cut than the initial depth of cut. Then, the confirming step is performed again, and when it is confirmed that all the cores C2 are exposed as shown in FIG. 11, the re-cutting step and the confirming step are completed.

After exposing the upper surfaces of all the cores C2, the units U held on the holding table 30 are transferred to the cleaning means 334 using the second transfer means 336 shown in FIG. After cleaning by the cleaning means 334 , the optical waveguide O is transported to, for example, a cutting device (not shown) by the second carrying-out means 336 , the optical waveguide O is cut into a predetermined size, and removed from the support member S.

[Second embodiment]
When the core C2 of the optical waveguide is completely buried as shown in FIG. 2, an exposing step of exposing one end or the other end of the core C2 on the side surface of the optical waveguide O is performed before the cutting step.

(exposure step)
(1) Cutting to a predetermined size When the core C2 of the optical waveguide O is completely covered with the clad C1, light cannot enter the core C2 as it is. The exposure of core C2 cannot be confirmed by the method used. In this case, for example, before cutting the upper surface of the optical waveguide O in the cutting step, the optical waveguide O is cut to a predetermined size along a predetermined cutting position. For example, as shown in FIG. 12, when the planned cutting position is defined by the intersecting planned cutting lines L, before performing the cutting step, for example, as shown in FIG. A cutting device is used to cut along the planned cutting line L with a cutting blade 65 or the like. In this case, the chuck table 66 of the cutting device holds the support member S side, and moves the rotating cutting blade 65 along the scheduled cutting line L while feeding the chuck table 66 in the -X direction, for example, so that the lower end of the cutting blade 65 By cutting to reach the support member S, the optical waveguide O is cut.

(2) Remnants removal After that, the remnants Oe shown in FIG. 14 are removed to expose one end or the other end of the optical waveguide O. As shown in FIG. At this time, as long as a cut groove Og as shown in FIG. 14 is formed in the optical waveguide O by division cutting into predetermined sizes, the light can be incident on the inside of the core C2 from the cut groove Og in the confirmation step described later. , the offcuts Oe may not be removed. Therefore, after cutting in the exposing step, (A) the end material Oe is removed, the optical waveguides O are removed from the support member S, and the individual optical waveguides O are divided into each predetermined size, and then the individual optical waveguides are cut. (B) The optical waveguide O is placed on the supporting member S while removing the offcuts Oe, and the shape of the optical waveguide O before the exposure step is performed. and (C) maintaining the shape of the optical waveguide O before the exposing step while the optical waveguide O is arranged on the support member S without removing the offcuts Oe. There are two possible implementation patterns.

(cutting step)
After the above exposure step is performed, the optical waveguide O has, for example, a cutting groove Og formed by the exposure step, and the scrap Oe is removed to expose one end or the other end of the core C2 from the side surface of the optical waveguide O. It is assumed that the core C2 is not exposed from the side surface of the optical waveguide O because the cut groove Og is provided by the exposure step but the scrap Oe is not removed. In any case, as described in the cutting step of the first embodiment, by controlling the processing feed means 5 and feeding the cutting tool 6 in the -Z direction by a predetermined length, The cutting edge 64a of the cutting tool is positioned at a position where a predetermined amount of cutting is performed. Then, the motor 62 rotates the spindle 60 having an axis in the Z-axis direction at a predetermined rotational speed, and along with this, the cutting tool 64 revolves around the spindle 60 at a predetermined rotational speed. On the other hand, the holding table 30 is moved in the -Y direction by Y-axis moving means (not shown). As a result, the turning cutting tool 64 cuts the upper surface of the optical waveguide O by a predetermined depth of cut to expose the upper surface of the core C2.

(confirmation step)
In the confirming step in the second embodiment, the light projecting method used in the confirming step in the first embodiment, that is, the light projecting means 15 emits light toward one end or the other end of the core C2 exposed on the side surface of the optical waveguide O. is projected toward the cutting groove Og produced by the exposure step, and the light is projected into the core C2 from the cutting groove Og A light projection method can also be used. In this case, as shown in FIG. 14, the light projecting unit 150 is controlled to adjust the height and the light projecting direction of the light emitting unit 152 so that the light projected from the light emitting unit 152 is directed toward the cutting surface Oa. Project the light so that it is vertical. Light entering the core C2 from the cut groove Og by projection passes through the core C2. At this time, if the upper surface of the core C2 is exposed by cutting in the cutting step, the incident light is emitted from the cut surface. On the other hand, if the upper surface of the core C2 is not exposed even after cutting by the cutting step, the light is not emitted from the cut surface Oa. This state is imaged from above the cut surface Oa by the imaging means 16 while the light projecting means 15 is projecting light. If the upper surface of the core C2 is exposed, the cutting surface Oa imaged by the imaging means 16 captures the light emitted from the core C2 and looks bright. Since no light is emitted from the core C2, it looks relatively darker than when the top surface of the core C2 is exposed. By analyzing the imaged cut surface Oa using, for example, image analysis software, the operator can determine whether or not the upper surface of the core C2 is exposed.

(additional cutting step)
As a result of confirmation by the confirmation step, if the core C2 is not exposed on the cutting surface Oa, cutting similar to the additional cutting in the additional cutting step described in the first embodiment is performed. The cutting tool blade 64a is positioned at a position lower than a predetermined height, and the upper surface of the optical waveguide O is cut again. When a plurality of cores C2 are embedded inside the clad C1 and there are cores C2 that are not exposed on the cutting surface Oa as shown in FIG. Cutting by the tool cutting means 6 and confirmation by the imaging means 16 are repeated. As shown in FIG. 10, in the additional cutting step, it is preferable to cut with a smaller depth of cut than the initial depth of cut. Then, the confirming step is performed again, and when it is confirmed that all the cores C2 are exposed as shown in FIG. 11, the re-cutting step and the confirming step are completed.

After the cutting by the additional cutting step is repeated and all the cores C2 are exposed, the unit U held on the holding table 30 is conveyed to the cleaning means 334 using the second conveying means 336 . After cleaning by the cleaning means 334 , the optical waveguide O is transported to, for example, a cutting device (not shown) by the second carrying-out means 336 , the optical waveguide O is cut into a predetermined size, and removed from the support member S.

As described above, by projecting light onto one end or the other end of the exposed core C2, the light emitted from the cut surface formed by cutting the upper surface of the optical waveguide O causes the cut surface of the core C2 to Therefore, it is possible to efficiently form the optical waveguide O in which the upper surface of the core C2 is exposed.

O: optical waveguide Oa: cut surface Og: cut groove Oe: edge material C1: clad C2: core
S: support member U: unit (optical waveguide O + support member S)
1: Bite cutting device 10: Base 100: Wall portion 101: Cleaning water storage portion 102: Drain port 11: Column 15: Light projecting means 150: Light projecting unit 151: Cylinder 152: Light emitting portion 16: Imaging means 17: Contact thickness gauge 170a: Thickness gauge 170b: Thickness gauge 18: Non-contact thickness gauge 19: Support bridge 20:
30: Holding table 39: Cover 39a: Accordion cover 330: Robot 331: First cassette
332: Second Cassette 333a: Temporary Placement Table 333b: Positioning Means 334: Washing Means 335: First Conveying Means 336: Second Conveying Means 5: Processing Feeding Means 50: Ball Screw 51: Guide Rail 52: Motor
53: Lifting plate 54: Holder
6: Bite cutting means 60: Spindle 61: Housing
62: Motor (Rotating drive of spindle) 63: Bit wheel 64: Bit tool 65: Cutting blade 66: Chuck table L: Planned cutting line

Claims (4)

A method for processing an optical waveguide in which a rod-shaped core having one end and the other end is embedded in a clad and disposed on a support member, comprising:
The core has at least one of the one end and the other end exposed,
a cutting step of holding the support member by a holding table and cutting the upper surface of the optical waveguide with a cutting tool positioned at a predetermined height to form a cut surface;
After performing the cutting step, light is incident from the exposed one end or the other end of the core, and whether or not the core is exposed to the cutting surface is confirmed based on the light emitted from the cutting surface. a confirmation step to
an additional cutting step of positioning the tool cutting edge at a position lower than the predetermined height position to cut the upper surface of the optical waveguide when the core is not exposed on the cut surface in the confirmation step; A method of processing an optical waveguide provided. An optical waveguide processing method according to claim 1,
the core is completely embedded in the cladding;
A method of processing an optical waveguide, further comprising an exposing step of exposing one of the one end and the other end before performing the cutting step. The optical waveguide processing method according to claim 1 or 2,
A plurality of cores are disposed on the support member in a state of being embedded in the clad,
The confirmation step confirms whether or not all the cores are exposed on the cutting surface,
A method of processing an optical waveguide, wherein the additional cutting step is performed when all the cores are not exposed. A holding table for holding an optical waveguide arranged on a support member with a rod-shaped core having one end and the other end embedded in a clad, and a cutting tool for cutting the optical waveguide held by the holding table. A tool cutting device comprising a tool cutting means having a blade,
light projecting means for projecting light toward the exposed one end or the other end of the core held by the holding table;
and an imaging means for imaging the upper surface of the optical waveguide substrate held by the holding table.

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