Method for manufacturing ferrule for optical fiber connector

Abstract

To provide a method for manufacturing a ferrule for an optical fiber connector which can realize a high manufacturing efficiency while securing a high size accuracy in a part where an optical fiber is held.SOLUTION: A method for manufacturing a ferrule 1 includes a through-hole part 3, the through-hole part 3 having a holding unit 31 for holding an optical fiber 100 by an optical fiber 100 inserted in the holding unit 31 and a tapered part 32 for guiding insertion of the optical fiber 100 into the holding unit 31, the aperture area of the tapered part becoming smaller in a place closer to the holding unit 31. A laser beam 64 is radiated to a ceramic material 50 of the ferrule 1 so that the holding unit 31 is formed and a laser beam 64 is radiated on a material 50' as a material after the holding unit 31 is formed so that the tapered part 32 is formed.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a ferrule for an optical fiber connector. [Background technology]

[0002] Optical fiber connectors that connect optical fibers to each other are known (see, for example, Patent Documents 1 and 2). The optical fiber connector described in Patent Document 1 holds the optical fiber with a resin ferrule. The optical fiber connector described in Patent Document 2 holds the optical fiber with a ceramic ferrule. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-186092 A [Patent Document 2] Patent No. 3917034 specification Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, semiconductor chips that emit optical signals passing through optical fibers have a structure in which light and electrical signals are converted at the entrance and exit of the semiconductor chip. However, with the increasing integration of electronic components, the amount of heat generated by the wiring inside the chip increases, limiting the performance of the chip. Therefore, technology that transmits optical signals through optical wiring to the core inside the semiconductor chip has been developed as a technology aiming at low power consumption. With this technology, it is necessary to connect optical fibers directly inside the semiconductor chip in order to shorten the length of the electrical circuit through which the electrical signal passes. In order to connect optical fibers inside the semiconductor chip, it may be necessary to mount an optical connector on the board on which the semiconductor chip is mounted.

[0005] In order to mount an optical connector on a board, it is possible to solder the optical connector to the board. When soldering an optical connector to a board, the temperature of the molten solder is about 260°C, which exceeds the heat resistance temperature of a resin connector such as that described in Patent Document 1, making it impossible to mount the connector on the board.

[0006] The ferrule for optical communication described in Patent Document 2 is made of transparent materials such as glass mainly composed of silicon oxide, glass ceramic, quartz glass, translucent alumina, etc., and has a high heat resistance, so it can be soldered to a board. However, Patent Document 2 does not include any idea of ​​soldering the ferrule for optical communication to a board.

[0007] The optical connector described in Patent Document 2 has a tapered shape at the end of the insertion hole on the side where the optical fiber is inserted, making it easier to insert the optical fiber into the insertion hole. The insertion hole and the tapered shape are formed by laser processing. In laser processing, the focal position of the laser light is moved relative to the ferrule material, and the irradiation position of the laser light is shifted to form a hole in the material. Therefore, the amount of movement of the laser light relative to the material is larger when forming a relatively large diameter tapered shape than when forming a relatively small diameter insertion hole.

[0008] In the configuration described in Patent Document 2, when manufacturing a ferrule, the insertion hole and the tapered shape are simultaneously formed in the material without distinction, so that it is necessary to form both the part that becomes the insertion hole, which requires low coupling loss performance, and the part that becomes the tapered shape, which does not require low coupling loss performance, with high accuracy. For this reason, when processing both the part that becomes the insertion hole and the part that becomes the tapered shape, processing must be performed with high dimensional accuracy over a long period of time, and the production efficiency of the ferrule is poor. In addition, since an optical fiber is a thin member with a diameter of less than 1 mm, the insertion hole also has a small diameter, and the movement amount of the laser focus position during laser processing is also small, so high positioning accuracy is required. Under such a premise, when forming an insertion hole and a tapered shape in the material at the same time, it is necessary to finely change the movement range of the laser focus position when forming a relatively small diameter insertion hole and when forming a relatively large diameter tapered shape. In this way, if the movement range of the laser focus position is finely changed for each part of the material, the accuracy of forming the insertion hole is likely to deteriorate.

[0009] The present invention has been made in consideration of the above problems, and aims to provide a method for manufacturing a ferrule for an optical fiber connector that can achieve high production efficiency while ensuring high dimensional accuracy in the area where the optical fiber is held. [Means for solving the problem]

[0010] The present invention relates to the following inventions.

[0011] (1) A method for manufacturing a ferrule having a through hole portion including a holding portion into which an optical fiber is inserted to hold the optical fiber, and a tapered portion having an opening area that becomes smaller toward the holding portion to guide insertion of the optical fiber into the holding portion, comprising: forming the holding portion by irradiating a ceramic material as a material of the ferrule with laser light; The material after the holding portion is formed is irradiated with the laser light to form the tapered portion. A method for manufacturing a ferrule for an optical fiber connector.

[0012] (2) The method for manufacturing a ferrule for an optical fiber connector according to (1) above, wherein the tapered portion is formed so that the surface roughness of the tapered portion is rougher than the surface roughness of the holding portion.

[0013] (3) The method for producing a ferrule for an optical fiber connector according to (1) or (2), wherein the tapered portion is formed at a rate higher than the holding portion.

[0014] (4) A method for manufacturing a ferrule for an optical fiber connector described in any one of (1) to (3), wherein the diameter of the laser light on the material when the tapered portion is formed is larger than the diameter of the laser light on the material when the holding portion is formed.

[0015] (5) A method for manufacturing a ferrule for an optical fiber connector according to any one of (1) to (4), comprising measuring the holding portions on the front and back surfaces of the ceramic material after forming the holding portions in the ceramic material and before forming the tapered portions, and calibrating a laser processing device that oscillates the laser light based on the measurement results.

[0016] (6) The method for manufacturing a ferrule for an optical fiber connector according to (5) above, further comprising the steps of: forming a tapered portion on the surface of the ceramic material; measuring the tapered portion on the surface of the ceramic material; and calibrating the laser processing device based on the measurement results. Effect of the Invention

[0017] According to the present invention, it is possible to manufacture a ferrule for an optical fiber connector that can realize high production efficiency while ensuring high dimensional accuracy in the portion that holds the optical fiber. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1(A) is a plan view of the ferrule, FIG. 1(B) is a rear view of the ferrule, and FIG. 1(C) is a cross-sectional view of the main part taken along line IC-IC in FIG. 1(B). [Diagram 2] FIG. 2 is a conceptual graph showing the tendency of surface roughness in the through-hole portion. [Diagram 3] FIG. 3 is a flowchart showing an example of a method for manufacturing a ferrule. [Figure 4] FIG. 4 is a flowchart showing an example of a method for manufacturing a ferrule. [Diagram 5] 5(A) and 5(B) are schematic views for explaining a method for producing a ferrule. [Figure 6] 6(A) and 6(B) are schematic views for explaining a method for producing a ferrule. [Figure 7] 7(A) and 7(B) are schematic views for explaining a method for producing a ferrule. [Figure 8] 8(A) and 8(B) are schematic views for explaining a method for producing a ferrule. [Figure 9] 9(A) and 9(B) are schematic views for explaining a method for producing a ferrule. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] [Ferrule] FIG. 1(A) is a plan view of the ferrule 1, FIG. 1(B) is a rear view of the ferrule 1, and FIG. 1(C) is a cross-sectional view of the main part taken along the line IC-IC in FIG. 1(B).

[0020] 1(A) to 1(C), the ferrule 1 constitutes a part of an optical fiber connector for holding an optical fiber 100. The cladding diameter of the optical fiber 100 is, for example, 125 μm. The ferrule 1 may be fixed to a circuit board (not shown) by being directly soldered to the circuit board, or may be fixed to the circuit board via an adapter (not shown) soldered to the circuit board, or ferrules may be connected to each other.

[0021] The ferrule 1 is a member formed from a ceramic material. Examples of the material of the ferrule 1 include ceramics mainly composed of zirconia, alumina, silicon nitride, silicon carbide, etc., and for example, ceramics mainly composed of zirconia. Specifically, partially stabilized zirconia ceramics mainly composed of tetragonal crystals containing ZrO2 as the main component and one or more of Y2O3, MgO, CaO, CeO2, Dy2O3, etc. as stabilizers can be mentioned. The material of the ferrule 1 preferably satisfies at least one of the following conditions: being a machinable ceramic, containing BN (boron nitride), and having a hardness in the range of 2.2 to 4.0 GPa. The material of the ferrule 1 is obtained by forming the powder of the above-mentioned raw material into a predetermined shape by extrusion molding, injection molding, press molding, etc., and then firing it.

[0022] The ferrule 1 is formed in a thin plate shape, for example, with a width of about 7 mm, a height of about 2 mm, and a thickness of about 0.5 mm. The ferrule 1 has a pair of guide pin holes 2, 2 and a plurality of through holes 3 arranged between the guide pin holes 2, 2.

[0023] The guide pin holes 2, 2 are holes into which guide pins (not shown) are inserted to position the ferrule 1.

[0024] The through hole portion 3 is a hole portion through which the optical fiber 100 is passed. The number of through hole portions 3 provided is equal to the number of optical fibers 100 held by the ferrule 1. The through hole portions 3 are arranged at equal pitches in the width direction of the ferrule 1. The through hole portions 3 are formed to penetrate the ferrule 1 in the thickness direction X of the ferrule 1, and open to a front surface 4 and a back surface 5 of the ferrule 1 in the thickness direction X.

[0025] The through hole portion 3 includes a holding portion 31 that holds the optical fiber 100 by inserting the optical fiber 100, and a tapered portion 32 whose opening area becomes smaller as it approaches the holding portion 31, for guiding the insertion of the optical fiber 100 into the holding portion 31.

[0026] The holding portion 31 contacts the optical fiber 100 to position the optical fiber 100 with respect to the ferrule 1. The wall surface 31c of the holding portion 31 is formed in a cylindrical shape that matches the shape of the outer peripheral surface of the optical fiber 100, and has the same diameter as the diameter of the optical fiber 100. The holding portion 31 is bonded to the optical fiber 100 by adhesive, but may be bonded by press-fitting. The holding portion 31 is longer than the tapered portion 32 (has a longer length in the thickness direction X). One end 31a of the holding portion 31 is continuous with the tapered portion 32. The other end 31b of the holding portion 31 is open to the back surface 5 of the ferrule 1. The tolerance of the difference (processing error) between the diameter at the one end 31a and the other end 31b of the holding portion 31 is about 1 μm, and dimensional accuracy is highly required. This is to reduce coupling loss caused by deviation of the optical axis of the optical fiber 100. For this reason, when forming the through-hole portion 3, it is difficult to ensure dimensional accuracy by mechanical processing such as cutting, so laser processing is used.

[0027] The tapered portion 32 is a portion with which the tip of the optical fiber 100 comes into contact when the optical fiber 100 is inserted into the through-hole portion 3 from the surface 4 side of the ferrule 1, thereby aligning the optical fiber 100 with the holding portion 31. One end 32a of the tapered portion 32 is open to the surface 4 of the ferrule 1. The other end 32b of the tapered portion 32 is continuous with one end 31a of the holding portion 31. The length of the tapered portion 32 in the thickness direction X of the ferrule 1 is, for example, less than 1 / 2 of the thickness of the ferrule 1, and is, for example, 1 / 3 or less, 1 / 4 or less, or 1 / 5 or less. The diameter of the wall surface 32c of the tapered portion 32 is continuously increased as it approaches the surface 4 of the ferrule 1. The tapered portion 32 is conically tapered, but may be a polygonal truncated pyramid shape such as a triangular truncated pyramid or a quadrangular truncated pyramid. The inclination angle θ of the tapered portion 32 with respect to the wall surface 31 c of the holding portion 31 may be constant, or may become smaller toward the holding portion 31 .

[0028] The surface roughness of tapered portion 32 is higher than the surface roughness of holding portion 31. The surface roughness of holding portion 31 refers to the surface roughness of wall surface 31c of holding portion 31. Moreover, the surface roughness of tapered portion 32 refers to the surface roughness of wall surface 32c of tapered portion 32.

[0029] The surface roughness of the tapered portion 32 is measured, for example, as follows. Specifically, at any one point in the circumferential direction of the wall surface 32c, the arithmetic mean roughness Ra is measured over a certain length in the thickness direction X (for example, a length of several tens of μm shown by an imaginary two-dot chain line) according to JIS (Japanese Industrial Standards) B 0601. Hereinafter, the arithmetic mean roughness Ra is also referred to as surface roughness. In this case, the surface roughness Ra can be measured using a laser microscope. This measurement operation is repeated at multiple points (for example, a total of five points) in the circumferential direction of the wall surface 32c. The average value of the obtained Ra is set as the surface roughness Ra0 of the tapered portion 32.

[0030] The surface roughness of the holding portion 31 can be exemplified by three points. Specifically, the surface roughness can be exemplified by a surface roughness Ra1 of a first portion 31d of the holding portion 31 adjacent to the tapered portion 32, a surface roughness Ra2 of a second portion 31e which is the center of the holding portion 31 in the thickness direction X, and a surface roughness Ra3 of a third portion 31f adjacent to the other end 31b of the holding portion 31.

[0031] The surface roughness Ra1 of the first portion 31d is measured, for example, in the same manner as the surface roughness of the tapered portion 32, as follows. Specifically, the surface roughness Ra is measured over a certain length in the thickness direction X at any one point in the circumferential direction of the wall surface 31c of the first portion 31d. This measurement is repeated at multiple points in the circumferential direction of the wall surface 31c. The average value of the obtained Ra is set as the surface roughness Ra1 of the first portion 31d. The measurement of the surface roughnesses Ra2 and Ra3 of the second portion 31e and the third portion 31f is similar to the measurement of the surface roughness Ra1 of the first portion 31d, except that the measurements are performed on the second portion 31e and the third portion 31f, respectively, instead of the first portion 31d.

[0032] Fig. 2 is a conceptual graph showing the tendency of surface roughness in the through-hole portion 3. As shown in Fig. 2, when the surface roughness of the tapered portion 32 of the through-hole portion 3 is Ra0, the surface roughness of the first portion 31d of the holding portion 31 is Ra1, the surface roughness of the second portion 31e is Ra2, and the surface roughness of the third portion 31f is Ra3, then Ra0>Ra1>Ra3>Ra2. Thus, the surface roughness Ra0 of the tapered portion 32 is rougher than any of the surface roughnesses Ra1 to Ra3 of the holding portion 31.

[0033] The reason why the surface roughness Ra0 of the tapered portion 32 is rough is that the time required for laser processing of the tapered portion 32 is shortened in consideration of the production efficiency of the ferrule 1. The tapered portion 32 only needs to align the optical fiber 100 with the holding portion 31, and is not a portion for holding the optical fiber 100, so there is no problem even if the surface roughness Ra0 of the tapered portion 32 is rough. The surface roughness Ra0 is, for example, a value not exceeding 10 μm.

[0034] The surface roughnesses Ra1 to Ra3 of the holding portion 31 are set to values ​​necessary for the holding portion 31 to hold the optical fiber 100. The reason why Ra1 is the largest among the surface roughnesses Ra1 to Ra3 is that the laser light when laser processing the tapered portion 32 is also irradiated to the first portion 31d, even though it is small, and the surface property of the first portion 31d is changed. The reason why the surface roughness Ra3 of the third portion 31f is the second largest among the surface roughnesses Ra1 to Ra3 after Ra1 is that the laser light is irradiated from the surface 4 side during the manufacture of the ferrule 1, so the length of the laser light is long and the energy density at the processed portion is low. If the energy density is low, the processed surface cannot be processed smoothly with high energy, and the surface roughness is likely to be rough. The reason why the surface roughness Ra2 of the second portion 31e is the smallest among the surface roughnesses Ra1 to Ra3 is that the laser light when forming the tapered portion 32 is not irradiated, and the laser processing is performed in a state where the energy density of the laser light is relatively high because the distance from the laser light source is not too far.

[0035] The above is a schematic configuration of the ferrule 1.

[0036] [Method of manufacturing ferrules] Next, a method for manufacturing a ferrule will be described. Figures 3 and 4 are flowcharts showing an example of a method for manufacturing the ferrule 1. When explaining the method while showing the flowchart, other figures besides the flowchart will also be shown as appropriate.

[0037] When manufacturing the ferrule 1, first, a trial process and adjustment of processing conditions as necessary are performed (steps S1 to S16). In the trial process, as shown in FIG. 5(A) and FIG. 5(B), a ceramic material 40, which is the material of the ferrule 1, is prepared (step S1). The ceramic material 40 is a material for trial processing, and is not shipped as a product in the state after the trial processing. Note that a processed product after processing the ceramic material 40 may be shipped as a product. As described above, the material 40 of the ferrule 1 is obtained by forming the powder of the above-mentioned raw material into a predetermined shape by extrusion molding, injection molding, press molding, or the like, and then firing it. Next, the material 40 is set on the processing table 61 (step S2) and is made ready for processing by the laser processing device 60.

[0038] The laser processing device 60 is, for example, a YAG laser or an excimer laser, and is, for example, a pulsed laser processing device that emits a nanosecond laser or a femtosecond laser. As a laser processing device, a femtosecond laser is preferable because it can reduce the surface roughness of the ferrule 1 by suppressing the generation of minute burrs.

[0039] The laser processing device 60 includes a laser light source 62, and a lens and a scanner (not shown) for making the light from the laser light source 62 focus at a predetermined position. The scanner includes a known configuration for changing the direction of the laser light, etc. The laser processing device 60 is configured to be able to move the position of the focal point 64a of the laser light 64 with respect to the material 40 (processing table 61) in three mutually orthogonal axial directions including the thickness direction X of the material 40 and a direction perpendicular to the thickness direction X by driving the scanner. With this configuration, the position of the focal point 64a of the laser light 64 can be changed in the thickness direction X of the material 40, the front-back direction (Y direction) horizontal to the thickness direction X, and the height direction (Z direction) perpendicular to the thickness direction. This allows the laser processing device 60 to change the processing position of the material 40 in the above three axial directions. Note that the laser processing device 60 may be configured to emit the laser light 64 and to be able to move the position of the focal point 64a in the above three axial directions, and the specific configuration is not limited. In this embodiment, the relative positions of the processing device 60 and the processing table 61 (material 40) are fixed.

[0040] With the material 40 set on the processing table 61, the laser processing device 60 irradiates the material 40 with laser light 64, thereby forming the holding portion 31 as a test processing (step S3). At this time, as shown in FIG. 5(B), it is preferable that the focal point 64a of the laser light 64 coincides with the processing position on the material 40. The diameter of the laser light 64 at the focal point 64a is about 5 to 30 μm. The holding portion 31 of the material 40 is a linear hole portion in a state in which the tapered portion 32 is not formed.

[0041] The focal point 64a of the laser light 64 is moved linearly or in a spiral in a direction perpendicular to the thickness direction X of the material 40. As a result, a holding portion 31 having a diameter larger than the diameter of the laser light 64 at the focal point 64a is formed. When the formation of the holding portion 31 at the same position in the thickness direction X is completed, the position of the focal point 64a is moved a predetermined amount closer to the back surface 5 of the material 40, and the position of the focal point 64a is again moved on a plane perpendicular to the thickness direction X by driving the scanner. By repeating these operations, the holding portion 31 that is straight in the thickness direction X of the material 40 and penetrates from the front surface 4 to the back surface 5 of the material 40 is completed. The material after the holding portion 31 is formed is shown in the drawing as material 40'.

[0042] Next, the holding portion 31 of the material 40' is measured (step S4). Specifically, as shown in FIG. 6(A), the diameter of the holding portion 31 on the front surface 4 of the material 40' and the diameter of the holding portion 31 on the back surface 5 of the material 40' are measured. These diameters are measured, for example, using a measuring device 70 equipped with an image sensor 71 that captures an image of the material 40'. The measuring device 70 measures these diameters by processing the captured image. The difference between the diameter of the holding portion 31 on the front surface 4 and the diameter of the holding portion 31 on the back surface 5 is the processing error. When the processing error is zero, these two diameters are the same, and it is found that the holding portion 31 has a highly accurate straight shape.

[0043] If the machining error of the holding portion 31 on the front surface 4 and the back surface 5 of the material 40' is equal to or less than a predetermined value (for example, 1 μm), the holding portion trial machining is judged to be acceptable (YES in step S5). On the other hand, if the machining error exceeds the predetermined value, the holding portion trial machining is judged to be unacceptable (NO in step S5), and the machining conditions are adjusted (step S6).

[0044] For example, the output of the laser light 64 from the laser light source 62 varies greatly over time. For this reason, in order to make the shape of the holding part 31 highly accurate and within the tolerance of the processing error, the output of the laser light 64 and the conditions for moving the focal point 64a in the three axial directions (such as the moving speed) are adjusted (calibrated) when adjusting the processing conditions (step S6).

[0045] After adjusting the processing conditions, similarly to step S3, as shown in Fig. 6(B), a trial processing for forming the holder 31 again on the material 40' is performed by the laser processing device 60 (step S7). Next, the holder 31 of the material 40' is measured (step S8). The measurement method at this time is the same as the holder measurement method in step S4.

[0046] If the machining error of the holding portion 31 on the front surface 4 and back surface 5 of the material 40' is equal to or less than the predetermined value, the holding portion trial machining is judged to be successful (YES in step S9). On the other hand, if the machining error exceeds the predetermined value, the holding portion trial machining is judged to be unsuccessful (NO in step S9), and machining condition adjustment (step S6), holding portion trial machining (step S7), and holding portion measurement (step S8) are performed again. These steps S6 to S8 are repeated until the machining error of the holding portion 31 on the front surface 4 and back surface 5 of the material 40' is equal to or less than the predetermined value.

[0047] In this manner, after the holding portion 31 is formed in the material 40, and before the tapered portion 32 is formed, the holding portions 31 on each of the front surface 4 and back surface 5 of the material 40' are measured, and the laser processing apparatus 60 is calibrated based on the measurement results.

[0048] After the result of the trial processing of the holding portion is acceptable (YES in step S5 or step S9), as shown in FIG. 7(A), laser light 64 is irradiated onto the material 40' using a laser processing device 60 to form the tapered portion 32 as trial processing (step S10).

[0049] At this time, it is preferable that the tapered portion 32 is formed so that the surface roughness Ra0 of the tapered portion 32 is rougher than the surface roughnesses Ra1 to Ra3 of the holding portion 31. Specifically, for example, as shown in FIG. 7(A), the focal point 64a of the laser light 64 is set to be shifted from the processing position on the material 40'. As a result, as viewed from the thickness direction X, the diameter of the laser light 64 on the material 40' when the tapered portion 32 is formed is larger than the diameter of the laser light 64 on the material 40' when the holding portion 31 is formed. As a result, the diameter of the laser light 64 at the point irradiated to the material 40' exceeds 5 to 30 μm. In this case, a wider range can be processed at once with the laser light 64.

[0050] It is preferable that the energy density on the material 40' when the tapered portion 32 is formed is lower than the energy density on the material 40' when the holding portion 31 is formed. As a result, the surface roughness Ra0 of the tapered portion 32 becomes higher than the surface roughnesses Ra1 to Ra3 of the holding portion 31. Note that the output of the laser light source 62 when the tapered portion 32 is formed may be lower than the output of the laser light source 62 when the holding portion 31 is formed.

[0051] The forming speed of the tapered portion 32 is preferably higher than that of the holding portion 31. In this case, the "forming speed" refers to at least one of the moving speed of the focal point 64a in the direction perpendicular to the thickness direction X of the material 40 (40') and the moving speed of the focal point 64a in the thickness direction X of the material 40 (40'). When the tapered portion 32 is formed, the focal point 64a of the laser light 64 is moved linearly or in a spiral manner in the direction perpendicular to the thickness direction X of the material 40'. This forms a tapered portion 32 having a diameter larger than the diameter of the laser light 64 at the position where the laser light 64 is irradiated. When the formation of the tapered portion 32 at the same position in the thickness direction X is completed, the position of the focal point 64a is moved a predetermined amount closer to the rear surface 5 side of the material 40', and the position of the focal point 64a is moved again on the plane perpendicular to the thickness direction X by driving the scanner. By repeating these operations, the tapered portion 32 is completed.

[0052] Next, the tapered portion 32 of the material 40' is measured (step S11). Specifically, as shown in FIG. 7(B), the diameter of the tapered portion 32 on the surface 4 of the material 40' is measured. This diameter measurement is performed, for example, using a measuring device 70 equipped with an image sensor 71 that captures an image of the material 40'. The measuring device 70 measures the diameter by processing the captured image. In this case, the difference between the measured diameter of the tapered portion 32 on the surface 4 and the designed diameter is referred to as the processing error.

[0053] If the machining error of the tapered portion 32 on the surface 4 of the material 40' is equal to or less than a predetermined value (for example, 1 μm), the trial machining of the tapered portion is judged to be acceptable (YES in step S12). On the other hand, if the machining error exceeds the predetermined value, the trial machining of the tapered portion is judged to be unacceptable (NO in step S12), and the machining conditions are adjusted (step S13).

[0054] When adjusting the processing conditions, similarly to the adjustment of the processing conditions in step S6, the output of the laser light 64 and the conditions for moving the focal point 64a in the three axial directions (such as the moving speed) are adjusted (calibrated) (step S13).

[0055] After adjusting the processing conditions, similarly to step S10, as shown in Fig. 8(A), a taper portion trial processing is performed by the laser processing device 60 to form the taper portion 32 again in the material 40' (step S14). Next, the taper portion 32 of the material 40' is measured (step S15). The measurement method at this time is the same as the taper portion measurement method in step S11.

[0056] If the machining error of the tapered portion 32 on the surface 4 of the material 40' is equal to or less than the predetermined value, the retaining portion trial machining is judged to be successful (YES in step S16). On the other hand, if the machining error exceeds the predetermined value, the tapered portion trial machining is judged to be unsuccessful (NO in step S16), and machining conditions are adjusted again (step S13), tapered portion trial machining (step S14), and tapered portion measurement (step S15) are performed. These steps S13 to S15 are repeated until the machining error of the tapered portion 32 on the surface 4 of the material 40' is equal to or less than the predetermined value.

[0057] After the tapered portion 32 is further formed on the surface 4 of the material 40 in this manner, the tapered portion 32 on the surface 4 of the material 40 is measured, and the laser processing device 60 is calibrated based on the measurement result.

[0058] When the above trial processing and processing condition adjustment (steps S1 to S16) are completed, a material 50 is prepared as the ferrule 1 instead of the material 40' as shown in FIG. 8(B) (step S17), and the material 50 is set on the processing table 61 (step S18). Note that the material 50 is the same material as the material 40 used in the trial processing, and is a material manufactured by the same manufacturing method as the material 40. In other words, the material 40 can be used as the material 50, and the material 50 can be used as the material 40.

[0059] Next, in the same procedure as in the trial processing of the retaining portion (step S3), the retaining portion 31 is formed in the material 50 (step S19), as shown in Fig. 9(A). This results in the formation of a material 50' having the retaining portion 31. Next, in the same procedure as in the trial processing of the tapered portion (step S10), the tapered portion 32 is formed in the material 50', as shown in Fig. 9(B) (step S20).

[0060] After the tapered portion 32 is completed, a finishing process may be performed by irradiating at least one of the holding portion 31 and the tapered portion 32 with a laser beam 64 from a laser source 62 .

[0061] The timing for forming the guide pin holes 2, 2 by the laser processing device 60 may be before or after the holding portion 31 and the tapered portion 32 are formed. Through these processes, the material 50′ becomes the ferrule 1.

[0062] [effect] As described above, according to this embodiment, when the ferrule 1 is manufactured from the material 50, the holding portion 31 and the tapered portion 32 are formed in separate steps. The holding portion 31 needs to be formed with high dimensional accuracy, while the tapered portion 32 does not need high dimensional accuracy because it only needs to guide the insertion operation of the optical fiber 100 into the holding portion 31. Therefore, the tapered portion 32 can be processed in a shorter time, and the production efficiency of the ferrule 1 can be improved. In addition, when the ferrule 1 is manufactured, since the holding portion 31 and the tapered portion 32 are formed in separate steps, there is no need to finely change the movement range of the laser light source 62 in one step, compared to the case where the holding portion 31 and the tapered portion 32 are formed collectively in a single step. In this way, as a result of not having to finely change the movement range of the laser light source 62 in one step, it is possible to suppress the positional deviation between the laser light source 62 and the material 50, and the accuracy of forming the holding portion 31 can be improved. As a result of the above, in the manufacturing method of the ferrule 1, it is possible to achieve high production efficiency while ensuring high dimensional accuracy of the holding portion 31 that holds the optical fiber 100.

[0063] Moreover, according to the present embodiment, the tapered portion 32 is formed so that the surface roughness Ra0 of the tapered portion 32 is rougher than the surface roughnesses Ra1 to Ra3 of the holding portion 31. This allows the process of forming the tapered portion 32 to be shortened, thereby increasing the production efficiency of the ferrule 1.

[0064] Furthermore, according to this embodiment, by making the tapered portion 32 formed at a rate faster than the rate at which the holding portion 31 is formed, the process of forming the tapered portion 32 can be shortened, and the production efficiency of the ferrule 1 can be increased.

[0065] Furthermore, according to this embodiment, the diameter of the laser beam 64 on the material 50 when the tapered portion 32 is formed can be made larger than the diameter of the laser beam 64 on the material 50 when the holding portion 31 is formed. This allows the tapered portion 32 to be formed over a wider range at once, shortens the time required to form the tapered portion 32, and increases the production efficiency of the ferrule 1.

[0066] Furthermore, according to this embodiment, after the holding portion 31 is formed on the material 40, a calibration operation (adjusting the processing conditions, step S6) may be performed before the tapered portion 32 is formed. In this case, the material 40 that can be used as the material for the ferrule 1 can be used as a test piece for calibration. Also, since the processing conditions can be adjusted by measuring the holding portion 31, which has a simple straight shape, the calibration operation can be shortened, and as a result, the production efficiency of the ferrules 1 can be improved.

[0067] Furthermore, according to this embodiment, after the tapered portion 32 is formed on the surface 4 of the material 40', a calibration operation (step S13) may be performed based on the measurement results of the tapered portion 32 on the surface 4 of the material 40'. In this case, it is sufficient to adjust the processing conditions for processing the tapered portion 32, which requires lower processing accuracy than the processing accuracy of the holding unit 31, so that time-consuming precise condition adjustment is not required and the calibration operation can be completed more quickly. Therefore, the calibration operation can be shortened, and as a result, the production efficiency of the ferrules 1 can be improved.

[0068] The embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment. Various modifications of the present invention are possible within the scope of the claims. [Industrial Applicability]

[0069] The present invention can be applied as a method for manufacturing a ferrule for an optical fiber connector. [Explanation of symbols]

[0070] 1 Ferrule 3 Through hole 31 Holding part 32 Tapered section 40,50 Material 60 Laser processing equipment 64 Laser Light 100 Optical Fiber

Claims

1. A method for manufacturing a ferrule having a through hole portion including a holding portion for holding an optical fiber by inserting the optical fiber, and a tapered portion having an opening area that becomes smaller toward the holding portion and for guiding the insertion of the optical fiber into the holding portion, comprising: forming the holding portion by irradiating a ceramic material as a material of the ferrule with laser light; The material after the holding portion is formed is irradiated with the laser light to form the tapered portion. A method for manufacturing a ferrule for an optical fiber connector.

2. 2. The method for producing a ferrule for an optical fiber connector according to claim 1, wherein the tapered portion is formed so that a surface roughness of the tapered portion is rougher than a surface roughness of the holding portion.

3. The method for manufacturing a ferrule for an optical fiber connector according to claim 2 , wherein the tapered portion is formed at a rate higher than the holding portion.

4. 3. The method for manufacturing a ferrule for an optical fiber connector according to claim 2, wherein a diameter of the laser light on the material when the tapered portion is formed is larger than a diameter of the laser light on the material when the holding portion is formed.

5. The method for manufacturing a ferrule for an optical fiber connector according to any one of claims 1 to 4, further comprising the steps of: after forming the retaining portion in the ceramic material, measuring the retaining portion on each of the front and back surfaces of the ceramic material before forming the tapered portion; and calibrating a laser processing device that oscillates the laser light based on the measurement results.

6. 6. The method for manufacturing a ferrule for an optical fiber connector according to claim 5, further comprising the steps of: forming the tapered portion on the surface of the ceramic material; measuring the tapered portion on the surface of the ceramic material; and calibrating the laser processing device based on the measurement result.

Images