JP3256286B2 - Optical connector core eccentricity measuring method and optical connector manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for measuring core eccentricity of an optical connector and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
1988 IEICE Fall National Convention, B-343
"High-precision dimensional measurement technology of multi-core connector" is known. FIG. 13 is a perspective view schematically showing this. The optical connector 101 is set on a stage (not shown) (a movable stage in the X and Y directions), and the illumination light source 10 is set from the rear end face.
2 illuminated. On the front end face side of the optical connector 101, an image pickup device 1 such as a CCD with an objective lens 103 interposed therebetween.
An image of the front end face of the optical connector 101 is formed on the imaging device 104.

Here, the optical connector 101 is provided with two guide pin holes 105 on both sides, and a number of fiber holes 106 are formed therebetween. Therefore, the illumination light from the illumination light source 102 is
Then, the light passes through the fiber hole 106 to be transmitted illumination light and enters the imaging device 104. Image data of transmitted illumination light from the front end face of the optical connector 101 is given to the image processing device 107.

For this reason, the image processing device 107 can determine the contour of the edge at the front end face of the guide pin hole 105 and the fiber hole 106, and the center position of the guide pin hole 105 and the fiber hole 106 can be determined from the result. Therefore, if the measured center position is compared with the designed center position, the so-called eccentric amount and eccentric direction are obtained,
Product evaluation becomes possible. The CRT 108 displays the imaging data and the measurement results so as to be visible.

[0005]

However, in the above-mentioned prior art, the eccentricity of the fiber hole 106 can be evaluated, but the eccentricity of the optical fiber itself inserted here is due to the clearance between the optical fibers. Cannot be evaluated. For this reason, when an optical fiber is inserted and actually used as an optical connector, there is a case where suitable optical coupling cannot be performed. In addition, the guide pin hole 105 serving as a reference for positioning is liable to cause “sagging” due to polishing on its front end face, and there is a disadvantage that the center position cannot be calculated accurately.

Accordingly, an object of the present invention is to provide a core eccentricity measuring method and a manufacturing method of an optical connector that can measure eccentricity with extremely high accuracy.

[0007]

According to the present invention, there is provided a method for measuring the eccentricity of a core of an optical connector, comprising the steps of: (1) forming at least two guide pin holes for determining a connection position; The first is to prepare an optical connector in which each is inserted and fixed in one or a plurality of fiber holes, and the end faces of the optical fibers are arranged in substantially the same plane at the front end face.
Step and (2) Prepare a dummy pipe made of a material harder than the constituent material of the guide pin hole and formed with a through hole, and measure in advance the eccentricity between the external center and the center of the through hole at the end face of this dummy pipe A second step,
(3) The third step of inserting the dummy pipe into the guide pin hole, and (4) Illumination light is incident on the through hole from the rear end face side, and transmitted illumination light is imaged on the front end face side, so that the center of the through hole is formed. A fourth step of obtaining the position, and (5) correcting based on the eccentricity measured in the second step, based on the center position of the through hole and the design data obtained in the fourth step,
A fifth step for determining the design position of the center of the core of the optical fiber inserted into the fiber hole; and (6) illuminating light is incident on the optical fiber inserted into the fiber hole from the rear end face side, and the optical fiber is incident on the front end face side. A step of obtaining the center position of the core of the optical fiber by imaging the illumination light emitted from the optical fiber, and measuring the deviation of the center position of the core of the optical fiber from the design position.

Here, it is desirable to insert a dummy pipe having a higher hardness than the optical connector into the guide pin hole, and it is also desirable to insert a dummy optical fiber into the through hole of the dummy pipe. In the method for manufacturing an optical connector according to the present invention, at least two guide pin holes for determining a connection position are formed, and one or a plurality of optical fibers are inserted and fixed in one or a plurality of fiber holes, respectively. A method for manufacturing an optical connector in which the end faces of the optical fibers are arranged on substantially the same plane at the front end face, comprising the step of measuring the core eccentricity by the above-described method for measuring the core eccentricity of the optical connector according to the present invention. It is characterized by.

[0009]

According to the configuration of the present invention, an optical fiber is inserted into a fiber hole in advance, and illumination light emitted from the optical fiber is imaged, so that the eccentricity of the core itself of the optical fiber can be measured. Also, by inserting the dummy pipe into the guide pin hole, the outline of the transmitted illumination light becomes clear, so that the design position of the core center of the optical fiber inserted into the fiber hole becomes accurate, and the eccentricity can be accurately measured. . Furthermore, if a dummy optical fiber is inserted into the dummy pipe, all the emitted illumination light can be measured under the same conditions, and the eccentricity can be determined accurately. In particular, in the present invention, the eccentricity between the center of the outer shape at the end face of the dummy pipe and the center of the through hole is measured in advance, or the eccentricity between the center of the outer shape at the end face of the dummy pipe and the center of the core of the dummy optical fiber is measured. By pre-measurement, even if there is such eccentricity, if the measurement is performed only once without rotating the dummy pipe with the dummy pipe inserted in the guide pin hole, the true The center position can be determined. Further, according to the optical connector manufacturing method of the present invention, since the method includes the step of measuring the eccentricity of the core by the above-described core eccentricity measuring method of the present invention, a stable optical connector with low loss can be obtained. .

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing an overall configuration of a core eccentricity measuring apparatus to which the method of the embodiment is applied, and FIG. 2 is a block diagram showing a functional configuration thereof.

As shown in FIG. 1, an optical connector 101 is set on a rotary stage 11 rotatable on a horizontal plane.
The rotary stage 11 is mounted on a Y-axis stage 12 that is linearly driven in a horizontal Y direction.
2 is mounted on an X-axis stage 13 that is linearly driven in the X direction orthogonal to the Y direction. A microscope 22 to which an objective lens 21 is attached is set above the optical connector 101, and a CCD camera 23 is mounted on the microscope 22. Further, a reflective AF is provided on the side of the microscope 22.
(Autofocus) devices 24 are mounted, and these are mounted on a Z-axis stage 14 that is movable in a vertical direction (Z direction).

On the other hand, the rotary stage 11 and the Y-axis stage 1
2. A length measuring device typified by a linear scale is provided on a side surface of the X-axis stage 13 and the Z-axis stage 14 that moves in parallel. The movement is detected by sensors 31 to 34, and a pulse corresponding to the amount of movement is generated. Output. Also,
A light source 40 is separately provided, and illumination light from the light source 40 is sent to the optical connector 101 via an optical fiber 41 or an optical lens (not shown).
This illumination light is supplied to the guide pin hole 105 of the optical connector 101.
To the optical connector 101, or to an optical fiber inserted into the fiber hole 106 of the optical connector 101.

As shown in FIG. 2, the rotary stage 11 is driven by a rotary drive mechanism 51, the Y axis stage 12 is driven by a Y axis drive mechanism 52, the X axis stage 13 is driven by an X axis drive mechanism 53, and the Z axis stage 14 is driven by a Z drive. The driving mechanisms 51 to 54 are constituted by a stepping motor or the like, and are each movable by a shaft driving mechanism 54.
Controlled by 5. In addition, sensors 31 to 34
Are counted by the counter 35, and the movement amount is monitored. In this embodiment, the rotary stage 11 is normally used in a fixed state. However, if necessary, the optical connector 101 can be driven and used if the optical connector 101 is largely inclined with respect to the X and Y axes.

The output (image data) of the CCD camera 23 is sent to an image processing device 61, which performs contour detection and center position calculation, and also sends it to an image AF device 62 for focusing. The image processing device 61 and the image AF
The output of the device 62 is sent to the CPU 63 and displayed on the CRT 64 as appropriate. Note that the CPU 63 is a reflection type AF device 24.
And a stage driver 55, and a light source 40A for illuminating the optical fiber 41 and a light source 40 for illuminating the guide pin hole 105 via the light source driver 42.
You control B.

FIG. 3 shows a state of the optical connector 101 in the embodiment. Two parallel guide pin holes 105 are formed on both sides, and a large number of fiber holes 106 are formed therebetween. The optical fiber 41 is inserted into the fiber hole 106, and the end face of the optical fiber 41 is exposed from the opening of the fiber hole 106 at the front end face of the optical connector 101. Illumination light from the light source 40A enters from the rear end of the optical fiber 41 via a lens (not shown), and illumination light from the light source 40B passes from behind the optical connector 101 via a lens (not shown). Guide pin hole 105
Is directly incident on.

FIG. 4 shows a detailed configuration of the reflection type AF device 24. This is a focus detection device based on the critical angle method, in which light is incident on the surface to be measured (the front end surface of the optical connector 101) from a direction perpendicular to the optical fiber 41 (a direction coaxial with the optical fiber 41). The measurement light from the light source 241 is a collimator lens 242
, And is incident on the polarization beam splitter 243 and is reflected in a right angle direction. The reflected light passes through the quarter-wave plate 244 to rotate the plane of polarization by 45 °,
The light is focused by a focusing (or objective) lens 245.

Here, when the surface to be measured is at the focal position of the condenser lens 245 (the state shown by the solid line), the reflected light passes through the same optical path and is again converted into parallel light by the condenser lens 245.
The plane of polarization is further rotated by 45 ° through the four-wavelength plate 244. As a result, the reflected light passes through the polarization beam splitter 243.
, The polarization plane of the critical angle prism 2 passes through the polarization beam splitter 243 as it is.
It is incident on 46. Here, since the critical angle prism 246 has the critical angle of θ in the drawing, the incident light is totally reflected, and the reflected light is incident on the two-divided sensor 247. Accordingly, light is equally incident on both light receiving surfaces of the two-divided sensor 247, and it can be seen that the measured surface is at the in-focus position.

On the other hand, when the surface to be measured is separated from the reflection type AF device 24 as indicated by a dotted line in the figure, the reflected light after passing through the condenser lens 245 becomes a converged light, and in this state, the critical angle prism 246. Then, the incident angle of the incident light on the reflection surface of the critical angle prism 246 is equal to or larger than the critical angle θ on one side and equal to or smaller than θ on the opposite side.
Only the light smaller than the critical angle θ is reflected and the two-split sensor 247
Is detected. Therefore, comparing the detection levels on both light receiving surfaces of the two-divided sensor 247, it is clear that the surface to be measured has separated. Conversely, when the surface to be measured is closer than the focal position, the output ratio of the two-divided sensor 247 is reversed, so that it can be seen that the surface has been approached. This enables focus detection.

In this critical angle method, as shown by a solid line in FIG. 5, measurement light for focusing operation is applied to the front end face of the optical connector 101 from the same direction as the incidence of light from the light source 40 on the optical fiber 41. Irradiation is performed on the end face of a certain optical fiber 41. In order to adopt this configuration, a wavelength-selective beam splitter 240 is provided on the optical path. That is, the beam splitter 240 transmits white light (solid line) from the light source 40 and transmits the white light (solid line) from the light source 241 of the reflective AF device 24.
(For example, a wavelength of 830 nm) is reflected. Thereby, the imaging by the CCD camera 23 and the focusing operation by the reflection type AF device 24 can be simultaneously executed.

As shown by a dashed line in FIG. 5, light from a light source 248 is incident in the oblique direction, and reflected light is
The image may be captured at 9 and focus may be detected. That is, in the present invention, not only the critical angle method as shown in FIG. 4 but also a focus detection by another method, for example, a knife edge method or an astigmatism method can be used.

The wavelength of light incident on the optical fiber 41, that is, the emission wavelength of the light source 40 is not particularly limited, but is preferably light having a wavelength longer than the cutoff wavelength of the optical fiber 41. That is, as shown in FIG. 6, if the wavelength is longer than the cutoff wavelength, the mode becomes a single mode, and the intensity distribution of the light emitted from the optical fiber 41 becomes a Gaussian distribution (FIG. 6A). Is found exactly. On the other hand, if the wavelength is shorter than the cutoff wavelength, a multimode light intensity distribution shown in FIG. However, even in this case, accurate focusing using the reflective AF device 24 enables accurate measurement of the core center.

As shown in FIG. 7A, the edge detection of the end face image for finding the core center of the optical fiber 41 is performed by examining the luminance change of the end face pattern in the X and Y directions to find a change point, ie, an edge. A circular pattern may be detected from this combination of edges, but may be detected by a memory batch method as shown in FIGS. 7B and 7C. That is, the light emitted from the optical fiber 41 is imaged by the CCD camera 23 while being divided into a plurality of imaging ranges, and stored in a frame memory incorporated in the image processing device 61. And FIG.
An equation of a circle is calculated from the address corresponding to the edge as shown in FIG. Thereby, the coordinates of the center of the circle, that is, the center position of the core of the optical fiber 41 are obtained.

Next, a method of measuring the eccentricity of the core of the optical connector, which is performed by using the above apparatus, will be described. FIG. 8 is a flowchart thereof. First, as shown in FIG.
1 is set on the upper surface of the rotary stage 11 (step 80).
1) The Y-axis stage 12 and the X-axis stage 13 are driven to position the microscope 22 in one of the guide pin holes 105, and the focusing operation is performed by the reflective AF device 24 and the Z-axis stage 14 (Step 802). . Next, the light source 40B
To emit illumination light to the guide pin hole 105,
An image of transmitted illumination light is taken by the D camera 23 (step 803). Thereafter, the same operation as in Steps 802 and 803 is performed with the positioning in the other guide pin hole 105 (Steps 804 and 805).

When the imaging data is obtained for both guide pin holes 105 as described above, the data is taken out from the frame memory of the image processing device 61, and is obtained as shown in FIG.
The contour is detected by the method shown in (c), and the center position of both guide pin holes 105 is calculated (step 8).
06). Thereafter, the design value of the core center position of the optical fiber 41 inserted into the fiber hole 106 as shown in FIGS. 9A and 9B is obtained (step 807). FIG. 9 (a)
Is a front view of the optical connector 101 as viewed from the front end face. When the optical connector 101 is projected onto the guide pin hole 105 and imaged, the pattern shown in FIG. 2B is obtained, and the center of the guide pin hole 105 can be calculated. Therefore, by using the center position and the design data, the design position where the core center of the optical fiber 41 should be located can be calculated.

Next, the operations of steps 808 and 809 in FIG. 8 are performed. That is, the microscope 22 is aligned with the optical fiber 41, and the focusing operation by the reflection type AF device 24 and the Z-axis stage 14 is performed. The illumination light is incident on the optical fiber 41 by the light source 40A, the emitted light is imaged by the CCD camera 23, and the result is processed in the frame memory of the image processing device 61. The above operation is performed for all the optical fibers 41 (step 810). When the operation is completed, the core center position of each optical fiber 41 is calculated (step 811). The contour pattern detection in this case is performed by the method shown in FIGS. 7B and 7C.

As described above, the design position of the core center of the optical fiber 41 is calculated by the operation up to step 807, and the measured position of the core center of the optical fiber 41 is calculated by the operation up to step 811. Ask. That is, when the pattern of the optical fiber 41 is imaged as shown in FIG. 9C and the center thereof is obtained, the difference Δx or Δy from the design value is obtained as shown in FIG. 9B. Note that FIG.
In (b), the circle is the actual measurement center, and the cross is the design center.

Next, a method for measuring the core eccentricity of the optical connector according to the second embodiment will be described. FIG. 10 is a longitudinal sectional view of the optical connector 101 in this case, and shows only the vicinity of the guide pin hole 105 in an enlarged manner. As shown, a dummy pipe 91 having a through hole 92 in the center axis direction is inserted into the guide pin hole 105, and the dummy pipe 91 is formed of a material having a higher hardness than the constituent material of the optical connector 101. I have. For this reason, the end of the through hole 92 is formed at an acute angle compared to the end of the guide pin hole 105 where the sag 93 is formed.

The sag 93 is caused by polishing of the front end face of the optical connector 101 or the like. If this occurs, the outline of the imaging screen of the transmitted illumination light becomes unclear, and the calculation of the center position cannot be performed accurately. . Therefore, a dummy pipe 91 as shown in FIG. 10 is inserted and the front end face is polished. And
If the transmitted illumination light from the through hole 92 is imaged by the CCD camera 23, an accurate center position can be calculated by accurate edge detection.

FIG. 11 is a cross-sectional view of the optical connector 101 when the above embodiment is partially modified. In this modification, an optical fiber 9 is provided in a through hole 92 of a dummy pipe 91 for dummy use.
4 has been inserted. For this reason, when the outer diameter of the optical fiber 94 is 125 μm, for example, the inner diameter of the through hole 92 is 126 μm. In this embodiment, illumination light from the light source 40B is incident on one end face of the optical fiber 94. Then, light emitted from the other end surface of the optical fiber 94 (the front end surface of the optical connector 101) is imaged by the CCD camera 23. According to this configuration, accurate center detection can be performed without using a material having a particularly high hardness for the dummy pipe 91 (of course, a high hardness may be used).

FIG. 12 is an end view of a dummy pipe 91 showing a modified example of the embodiment of FIGS. Through hole 9
2 is desirably formed on the center axis of the dummy pipe 91, but is actually easily displaced.
ΔX, ΔY), the center of the guide pin hole 105 of the optical connector 101 cannot be accurately recognized. Therefore, FIG.
After performing the first measurement as shown in (b), the dummy pipe 91 is rotated by 180 ° to perform the second measurement.
Then, the measured two center positions of the through-hole 92 are point-symmetric with respect to the original center position of the dummy pipe 91, so that the true center position can be obtained by averaging the measured values of both. . It is also conceivable to provide means for measuring the eccentricity of the core of the optical fiber itself inserted in the through hole or the through hole with respect to the outer diameter of the dummy pipe, and measure the eccentricity of the optical fiber itself in advance. In this case, the measurement need only be performed once without performing the measurement twice as described above, and the correction may be performed later using the eccentricity data of the optical fiber itself.

[0031]

According to the present invention, an optical fiber is inserted into a fiber hole in advance, and the illumination light emitted from the optical fiber is imaged, so that the eccentricity of the core itself of the optical fiber can be measured with extremely high accuracy. it can. Also, if a dummy pipe made of a high-hardness material is inserted into the guide pin hole, the outline of the transmitted illumination light becomes clear, so that the design position of the core center of the optical fiber inserted into the fiber hole becomes accurate, and the eccentricity Can be measured more accurately. Furthermore, if a dummy optical fiber is inserted into the dummy pipe, all the emitted illumination light can be measured under the same conditions, and the eccentricity can be determined accurately. In addition, the optical connector whose eccentricity is measured by this method can always be supplied to the market as a stable product with low loss, and is also used for selecting a master connector at the time of loss measurement,
An optical connector with extremely high reliability can be selected.

[Brief description of the drawings]

FIG. 1 is a perspective view of an apparatus to which an optical connector core eccentricity measuring method according to an embodiment is applied.

FIG. 2 is a block diagram of an apparatus to which the method for measuring the core eccentricity of the optical connector according to the embodiment is applied.

FIG. 3 is a perspective view of the connector according to the embodiment.

FIG. 4 is an explanatory diagram of focus detection by a critical angle method.

FIG. 5 is an explanatory diagram of focus detection.

FIG. 6 is an intensity distribution diagram of light emitted from an optical fiber.

FIG. 7 is an explanatory diagram of center position detection.

FIG. 8 is a flowchart showing a method of measuring the core eccentricity of the optical connector according to the embodiment.

FIG. 9 is a view of an optical connector showing a method for measuring core eccentricity of the optical connector according to the embodiment.

FIG. 10 is a sectional view of a main part of an optical connector showing a modification.

FIG. 11 is an essential part cross-sectional view of an optical connector showing a modification.

FIG. 12 is a view of a dummy pipe showing a modification.

FIG. 13 is a perspective view showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 101 ... Optical connector, 102 ... Illumination light source, 104 ... Imaging device, 105 ... Guide pin hole, 106 ... Fiber hole, 107 ... Image processing apparatus, 11 ... Rotation stage, 12
... Y-axis stage, 21 ... Objective lens, 22 ... Microscope, 2
3 ... CCD camera, 24 ... Reflection type AF device, 14 ... Z axis stage, 40 ... Light source, 41 ... Optical fiber, 51 ... Rotation drive mechanism, 52 ... Y axis drive mechanism, 53 ... X axis drive mechanism,
54 ... Z-axis drive mechanism, 55 ... Stage driver, 61 ...
Image processing device, 62: Image AF device, 63: CPU, 6
4 CRT, 241 light source, 242 condensing lens, 24
3. Polarizing beam splitter, 244 ... 1/4 wavelength plate, 2
45: condenser lens, 246: critical angle prism, 247 ...
2-split sensor, 240: beam splitter, 92: through hole, 91: dummy pin, 94: optical fiber.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Shinji Nagasawa 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-4-199008 (JP, A) JP 60-67833 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 11/00 G02B 6/36-6/40

Claims (3)

(57) [Claims] At least two guide pin holes for determining a connection position are formed, and one or a plurality of optical fibers are fixed in one or a plurality of fiber holes in an inserted state, respectively. A first step of preparing an optical connector in which the end faces of the optical fibers are arranged on substantially the same plane; and preparing a dummy pipe having a through hole formed of a material harder than the constituent material of the guide pin hole, A second step of measuring in advance the eccentricity between the center of the outer shape and the center of the through hole at the end face of the dummy pipe; a third step of inserting the dummy pipe into the guide pin hole; and illuminating the through hole from the rear end face side. A fourth step of injecting light and imaging transmitted illumination light on the front end face side to determine a center position of the through hole; and the through hole determined in the fourth step A fifth step of obtaining a design position of a core center of the optical fiber inserted into the fiber hole by correcting based on the eccentricity measured in the second step, based on the center position and the design data, A sixth step of illuminating the optical fiber inserted into the hole from the rear end face side and imaging the illuminating light emitted from the optical fiber at the front end face side to determine the center position of the core of the optical fiber; And measuring a deviation of the center position of the core of the optical fiber from the design position. 2. At least two guide pin holes for determining a position at the time of connection are formed, and one or a plurality of optical fibers are fixed in one or a plurality of fiber holes, respectively, in an inserted state. A first step of preparing an optical connector in which the end faces of the optical fibers are disposed on substantially the same plane; and preparing a dummy pipe having a through hole formed by inserting a dummy optical fiber, and an end face of the dummy pipe. A second step of measuring in advance the eccentricity between the outer shape center and the center of the core of the dummy optical fiber; a third step of inserting the dummy pipe into the guide pin hole; The illumination light is incident from the end face side, and the illumination light emitted from the dummy optical fiber is imaged on the front end face side, whereby the core of the dummy optical fiber is captured. A fourth step of calculating the center position of the dummy optical fiber based on the eccentricity measured in the second step, based on the center position and the design data of the core of the dummy optical fiber obtained in the fourth step. A fifth step of determining a design position of a core center of the optical fiber inserted into the fiber hole, and irradiating illumination light to the optical fiber inserted into the fiber hole from a rear end face side, A sixth step of obtaining the center position of the core of the optical fiber by imaging the illumination light emitted from the optical fiber, and shifting the center position of the core of the optical fiber inserted into the fiber hole from the design position. A method for measuring core eccentricity of an optical connector, comprising: 3. At least two guide pin holes for determining a position at the time of connection are formed, one or a plurality of optical fibers are fixed in one or a plurality of fiber holes respectively in an inserted state, and a front end face is formed. A method for manufacturing an optical connector in which the end faces of the optical fiber are arranged on substantially the same plane.
Te, the optical connector manufacturing method characterized by comprising the step of measuring the core eccentricity by the core eccentricity determination method of an optical connector according to claim 1 or 2.