JP2592906B2 - Measuring device for connector structural parameters - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention measures the structural parameters (inner diameter, outer diameter, eccentricity of inner diameter / outer diameter) of a cylindrical object, for example, a single-core optical fiber connector with high accuracy. The present invention relates to a device that performs

<Prior Art> Today, in a public communication line using an optical fiber, a line using a single mode optical fiber is becoming mainstream for the purpose of large-capacity transmission and diversification of services. One of the important technologies when constructing a transmission line using this single mode optical fiber is a technology for connecting single mode optical fibers to each other with low loss. In order to connect single mode optical fibers to each other with low loss using a connector, not only the structural parameters (outer diameter, mold field diameter, mode field eccentricity) of the optical fiber itself must be stabilized but also high accuracy. It is necessary to stabilize the structural parameters (inner diameter, outer diameter, eccentricity of inner diameter / outer diameter). That is, a high-precision technology for measuring the structural parameters of the connector is required.

Here, a conventional method for measuring the dimensions of a single-core connector will be described with reference to FIG. In FIG. 2 (a), 1 is a laser measuring device, 2 is a stage, 3 is a single-core ferrule of a connector,
3a denotes an end face of a ferrule, 4 denotes an image pickup optical system, and 5 denotes an image pickup device. The dimension measurement is performed by imaging the end face 3a of the ferrule.
3mm, inner diameter is 125μm (fiber diameter), so when the whole image is captured with the ferrule fixed,
Sufficient accuracy cannot be obtained due to the limitation of the resolution of the image sensor 5. For example, a one-dimensional CCD as an image recognition sensor
When a line sensor is used, the number of pixels (resolution) is about 2,000, and the resolution when observing a 3 mm specimen is 1.5 μm / pixel.

Therefore, in order to improve this resolution, the inner diameter (b) at the end face 3a of the ferrule shown in FIG.
And (c) and the outer diameters (a) and (d) are separately imaged and moved to grasp the whole. That is,
The imaging optical system 4 takes in the partial image of the end face 3a of the ferrule 3 into the imaging device 5, and (a), (b), and (c) of FIG.
The recognition of each point in (d) is performed by moving the stage 2 in the aa 'direction. In this case, the laser length measuring device 1 is used for accurately measuring the amount of movement of the connector.

<Problems to be Solved by the Invention> However, when the structural parameters of the connector are to be measured as described above, there are the following problems. That is, the laser length measuring device 1 is used for measuring the amount of movement of the ferrule, but when performing laser length measurement, it is necessary to use a frequency-stabilized laser for detecting the movement of the stage 2 at a very short distance. , The system becomes expensive. In addition, when the optical path of the laser beam becomes longer, it is necessary to pay attention to environmental conditions such as temperature change.

Next, as shown in FIG.
If 3a is not formed flat, outer diameter position (a)
When separately recognizing (d) and the inner diameter position (b), it is necessary to move the stage 2 in the bb 'direction and refocus the imaging optical system 4, but this focusing is performed at a small distance. Due to the alignment, if the axial distance is large, such as between the outer diameter position and the inner diameter position, focusing at each position is very troublesome.

Further, if the edges of the recognition points (a), (b), (c), and (d) are not sharp, there is a problem that the recognition of the edges by reflected illumination cannot be performed accurately.

In view of the above-described problems, the present invention provides a connector structural parameter measuring device that does not use a laser length measuring device, eliminates troublesome focusing, and performs accurate recognition without using reflected illumination. .

<Means for Solving the Problems> A configuration of the present invention that achieves the above object includes a V-block, which is a single-core ferrule, for positioning a subject in a radial direction, and a contact-type measuring device that presses the subject on the V-block. A long device, a stage on which the subject is mounted, and which rotates at regular intervals about an axis, a light source provided on one end surface in the axial direction of the subject, and an imaging optical system provided on the other end surface in the axial direction, An image recognizing unit and a CPU that determine an inner diameter of the object imaged by the imaging optical system and an outer diameter of the contact type length measuring device by comparing with a standard sample whose dimensions are known in advance.
And a device for measuring structural parameters of a connector having:

<Embodiment> An embodiment of the present invention will now be described with reference to FIG. In FIG. 1, reference numeral 3 denotes a cylindrical ferrule serving as a subject, 4 denotes an imaging optical system on one end side of the ferrule in the axial direction, and 5 denotes an imaging element. 6 is ferrule 3
, A stage for rotating the ferrule 3, a V-block 7 for positioning the ferrule 3 in the radial direction, an image processing device 10 connected to the image sensor 5, a contact-type length measuring device 11 for contacting and pressing the radial side surface of the ferrule 3. , 9 is a CPU for processing data obtained by the image processing device 10 and the contact type length measuring device 11, 12 is a light guide for introducing light into the ferrule 3, and 13 is a light source.

In the measurement, first, the lamp 13 is turned on, and the inner wall of the ferrule 3 is transmitted and illuminated through the ride guide 12. The edge (c) of the ferrule end surface 3a that has been transmitted and illuminated is formed as an image on the image sensor 5 via the imaging optical system 4, and image information corresponding to the edge (c) is transmitted from the image sensor 5 to the image processing apparatus. Sent to 10. Then, data as a processing result of the image processing device 10 is transferred to the CPU 9. Here, for example, only the edges (c) and (b), which are the inner diameters of the ferrule, are measured, and an image is taken on the same plane. Therefore, if focusing is performed first, further focusing is required. Disappears.

On the other hand, the side surface of the ferrule 3 is pressed against the V-block 7 by the pressing of the contact type length measuring device 11,
The data of 11 is transferred to the CPU 9. In this case, stage 6
The ferrule 3 is rotated by the rotation of. However, even if there is a pressing force of the contact type measuring device 11, depending on the conditions, it can be rotated without any trouble by the force (for example, up to about 100g pressing force). Is known. When a pressing force that hinders rotation is applied to the ferrule 3, the rotation is performed by releasing the pressing by the length measuring device 11. In this way, a contact length measuring instrument
By means of 11, the outer diameter will be measured.

Then, by rotating the rotary stage 6 constant angular intervals, the position of the inner wall by the image processing apparatus 10 information X _i, the position information X _o of the outer diameter due to the contact length measuring instrument determined at each rotational angle, advance dimensions known X _i standard sample of, X _o the inner diameter of the test connector by comparing (each, represent _o) and an outer diameter is obtained.

That is, when the inner diameter of the ferrule as a subject is D _i , the outer diameter is D _o , the inner diameter of the standard sample is _i , and the outer diameter is _o , the following equations (1) and (2) are obtained.

Here, 2θ indicates the opening angle of the V block 7.

Further, the eccentricity (δ) between the inner diameter and the outer diameter can be obtained by the equation (3) since the eccentricity is usually smaller than the inner diameter.

Grace inner diameter / outer radially polarized Kokororyou is X _o -X _i may be determined from Fuhaba plot and fitting shiso a sine function to it against the rotation angle of the ferrule. Used in equations (1) and (2)
X _o , _o , X _i , and _i may use an average value for each angle.

Thus, by using the connector structure parameter measuring system according to the present embodiment, all the disadvantages of the conventional method can be overcome, and the structure parameters of the connector can be easily and accurately measured. When the method according to this embodiment is used, the outer diameter and inner diameter of the reference sample need to be determined in advance, but the reference sample does not need to be a connector, and
A metal sleeve or the like whose outer diameter is close to the dimensions of the connector may be used. It is easy to measure the inner diameter and outer diameter of the reference sleeve in which the sagging at the ends of the inner wall and the outer wall is suppressed with high accuracy by using the laser length measuring device shown as the conventional method.

<Specific Example> A single-core optical connector ferrule having an inner diameter of 0.125 MM and an outer diameter of 2.5 MM was measured by the method according to the above-described embodiment. A halogen lamp was used as illumination light and guided by a bundle-type optical fiber.

The ferrule 3 to be inspected is rotated every 30 °, and the position of the inner wall of the ferrule is recognized by the number of pixels 500 × 50 through the × 100 objective lens.
The two-dimensional imaging device 5 of 0 received light, and the outer wall of the ferrule was recognized by using a contact-type length measuring device 11 reading 0.01 μm. The reproducibility of the measured values in ten repeated measurements was 0.09 μm for the outer diameter, 0.12 μm for the inner diameter, and 0.07 μm for the eccentricity as a standard deviation.

<Effect of the Invention> As described above, by using the apparatus according to the present invention, the use of the laser length measuring device, the use of the reflected light, and the focusing of the inner diameter and the outer diameter, which have the disadvantages of the conventional method, can be performed. Everything was overcome,
Highly accurate measurement of structural parameters of single core ferrules is now possible. By adding an automatic ferrule attachment / detachment mechanism to this apparatus, it is also possible to perform highly accurate continuous measurement.

[Brief description of the drawings]

FIG. 1 is a block diagram of a ferrule structure parameter measuring system according to an embodiment of the present invention, FIG. 2 (a) is a block diagram of a ferrule structure parameter measuring system according to a conventional method, and FIG. 2 (b) is a configuration of a ferrule end face. FIG. In the figure, 3 is a ferrule, 3a is an end face, 4 is an imaging optical system, 5 is an imaging device, 6 is a stage, 7 is a V block, 11 is a contact type length measuring device, and 13 is a lamp.

Claims (1)

(57) [Claims] 1. A V-block for positioning a subject in a radial direction, which is a single-core ferrule, a contact-type length measuring device for pressing the subject on the V-block, and placing the subject on a fixed angle around an axis. A stage, a light source provided on one end face side in the axial direction of the subject, and an imaging optical system provided on the other end face side in the axial direction, an inner diameter of the subject imaged by the imaging optical system, and the contact type measurement. An image recognizing unit and a CPU for determining an outer diameter by a long device by comparing with a standard sample whose dimensions are known in advance, and a measuring device for measuring structural parameters of a connector.