JP2006194626A - Eccentricity measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a sure and precise eccentricity measuring device, in the eccentricity measuring device of a hollow cylinder. <P>SOLUTION: A semiconductor laser light projection device 9 is positioned at a location for irradiating an area close to the emission surface of an object 1 to be measured with light. Semiconductor laser beams 10, hitting against the object 1 to be measured, generate a light speckle pattern. The speckle pattern is photographed by a camera 5 and the image is processed by an image processing inspection apparatus 6, thus determining the presence or absence of rotation. The camera 5 and the image processing inspection apparatus 6 can also be utilized for measuring eccentricity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to eccentricity measurement of a hollow cylinder, and more particularly to an eccentricity measuring apparatus suitable for highly accurate eccentricity measurement such as an optical fiber ferrule.

For example, in a ferrule for an optical fiber, when a ferrule whose center hole and eccentricity exceed the limit is used, the reflection of the end face increases due to the optical axis misalignment of the optical fiber and the coupling loss increases. Therefore, measurement of the amount of eccentricity has been indispensable for the ferrule for optical fibers.
In general, a device for measuring hole eccentricity of a hollow cylinder such as an optical fiber ferrule is a rotating device that rotates the ferrule with reference to the outer diameter, an illumination device that illuminates the hole of the ferrule, a camera that shoots a hole image of the ferrule, and a camera. It consists of an image processing device that measures the eccentricity of the hole from the photographed image by image processing. The eccentricity is measured by the difference in the center coordinates of the image of the hole in the non-rotating ferrule and the image of the hole rotated on the basis of the outer diameter. The pass / fail judgment is performed. (For example, Patent Document 1)

  In this apparatus, when the ferrule does not rotate for some reason, the eccentricity of the hole is measured as zero, and there is a problem that erroneous measurement occurs. As a countermeasure, if the eccentricity is lower than a certain value, it is determined that the ferrule is not rotating and it is determined as a defective product. However, there remains a problem that a ferrule with very good eccentricity is determined as a defective product. ing.

JP 2004-61274 A

  In order to cope with the above problem, a means for reliably detecting the rotation of the ferrule is required. However, since the ferrule itself has a small diameter and the apparatus is equipped with a rotating device or the like, a rotation detecting means is installed. There is almost no space. The present invention has been made to solve this problem, and relates to providing rotation detection of a small cylindrical eccentric measuring device such as a ferrule that can detect the rotation of the ferrule with a simple configuration.

In order to achieve the above object, according to the first aspect of the present invention, a hole image is photographed with a camera while rotating the hollow cylinder with respect to the eccentricity of the hole and the outer periphery of the hollow cylinder, and the amount of eccentricity is determined from the change in the position of the hole image. In the apparatus for measuring the above, a means for detecting the presence or absence of rotation by irradiating the hollow cylinder with a laser beam and detecting a change in optical speckle by the laser beam is provided. When the hollow cylinder is irradiated with laser light, a speckle pattern (interference fringe) is generated.
The speckle pattern is irregular reflection corresponding to the unevenness of the object surface caused by irradiating the surface of the object with laser light, and the speckle pattern has the property of moving in parallel with the movement of the object. It is used for movement detection.
When the cylinder is rotating, the speckle pattern changes according to the rotation. On the other hand, when it is not rotated, the speckle pattern does not change. The presence or absence of rotation can be detected by the change in the speckle pattern. Specifically, the presence or absence of rotation can be detected by detecting with a photo sensor such as a camera image change such as a CCD camera described later or a photomultiplier tube and detecting a signal change of the sensor. That is, any means that can observe and detect speckles can be applied. In addition, as a laser beam to be irradiated, a semiconductor laser having a wavelength of 400 nm to 700 nm and a class 2 or lower can be suitably used in consideration of safety. The classification is based on JIS C6801 “Laser Safety Terms”. As described above, basically, it is only necessary to add a means for irradiating laser light and a means for detecting speckle, so that it can be easily added to an existing apparatus.

  According to a second aspect of the present invention, the hollow cylinder is irradiated with laser light, an optical speckle image by the laser light is taken with a camera, and the presence or absence of rotation is detected from the speckle image. Since the speckle image captured by the camera changes according to the rotation, the presence or absence of the rotation can be detected from the image change. Specifically, a method of displaying an image on a monitor and discriminating by an operator can be applied as a simple method.

  According to a third aspect of the present invention, the camera that captures the optical speckle image by the laser beam and the camera that captures the hole image for the eccentricity measurement are the same. Since the camera for detecting rotation and the camera for measuring eccentricity can be shared, the presence or absence of rotation can be detected with a simpler configuration.

  According to a fourth aspect of the present invention, the presence / absence of rotation is detected by performing image processing on an optical speckle image by laser light. Image processing enables flexible response when the state of the optical speckle image changes. For example, even when the density or the like of the optical speckle image changes due to fluctuations in the intensity of the laser beam, stable rotation detection can be performed by automatically correcting and dealing with the image density to be constant. It is also possible to set an area suitable for rotation detection from the entire image area and use only this area for rotation detection.

  According to the present invention, since the presence or absence of rotation can be reliably detected with a simple configuration in a small cylindrical eccentricity measuring apparatus such as a ferrule, there is an effect that highly accurate eccentricity measurement is possible.

    Hereinafter, embodiments of the present invention will be described with reference to examples.

    FIG. 1 is a diagram illustrating an outline of an eccentricity measuring apparatus that does not include the rotation detection unit of the present invention. A hollow cylindrical object 1 such as an optical fiber ferrule is placed on a pallet on a base 2 having, for example, a V-shaped groove whose position does not change even when the object is rotated. Installed by a person or robot. The DUT 1 rotates on the base 2 by bringing the DUT 1 into contact with a rotating mechanism 3 such as a roller driven by a motor, for example. The illuminating device 4 provided with a halogen light source or the like is installed at a position where illumination light enters the hole of the DUT 1. A camera 5 such as a CCD camera with a lens is installed at a position where the vicinity of the hole of the DUT 1 from which illumination light is emitted can be photographed, and photographs the rotating hole 7. The camera 5 is connected to the image processing inspection apparatus 6, digitizes the eccentricity with respect to the outer diameter from the change in the image of the rotating hole 7 that has been photographed, performs pass / fail determination at a certain threshold value, and outputs the determination result. .

  The object to be measured that has passed the pass / fail judgment is further removed from the stand by the person or robot, and transferred to a pallet or the like for each judgment result.

FIG. 2 is an example of an image of a hole imaged by the camera 5 in the eccentricity measuring apparatus having the configuration of FIG. This image is a partially enlarged image in order to effectively capture the displacement of the boundary between a bright part and a dark part, which will be described later. The hole portion 7 is bright and the outer portion 8 of the hole is photographed dark because the illumination light from the illuminating device located at the opposite position through the camera and the hole portion is emitted.
From this image, a boundary between a bright part and a dark part is obtained by, for example, an image processing inspection apparatus 6 such as a personal computer equipped with an image input board that includes an image input board and processes an image input from the image input board. Eccentricity is quantified based on the position change of the boundary.
Although the outer diameter of the ferrule is accurately molded, only the image change of the rotating hole is used, but the eccentricity is caused by the image of the non-rotating hole and the image of the rotating hole. It may be digitized to make a pass / fail judgment.

FIG. 3 is a diagram showing an outline of an eccentricity measuring apparatus provided with the rotation detection unit of the present invention. In the apparatus shown in FIG. 1, for example, a semiconductor laser projector 9 (Keyence laser sensor LV-H32, wavelength 650 nm, using only a Class 2 laser projector) is applied to the position near the emission surface of the object 1 to be measured. Install. The semiconductor laser beam 10 that has hit the device under test 1 generates an optical speckle pattern. If this speckle pattern is photographed by the camera 5 and this image is processed by the image processing inspection device 6, the presence or absence of rotation can be determined.
Specifically, when the ferrule is irradiated with laser light, part of the irradiated laser light passes through the ferrule, is reflected by the hole, and enters the camera through a plurality of paths. Since the laser light is light color light, interference occurs due to a path difference (phase difference), and interference fringes are generated. Since the hole portion is illuminated with a halogen light source, the interference fringes are actually generated but are not visible as an image. However, except for the holes, the interference fringes are visible because there is no influence of illumination.
Needless to say, the camera 5 and the image processing inspection apparatus 6 can also be used for measuring eccentricity.
The irradiation position of the laser beam is an angle that crosses the hole at the tip of the hollow cylinder as shown in FIG. 3 so that the speckle can be reliably observed on a camera that captures a bright and dark image of the light from the illumination device. It is desirable to irradiate with.

    FIG. 4 shows an example in which the camera 5 captures a speckle pattern irradiated with the semiconductor laser beam 10 when the DUT 1 is not rotating. A fine shading portion 11 peculiar to the speckle pattern is seen in the outer portion 8 of the dark hole. On the other hand, FIG. 5 shows an example in which the speckle pattern irradiated with the semiconductor laser beam 10 is photographed by the camera 5 when the DUT 1 is rotating. The fine shading 11 that was clear when not rotating is unclear. It is easy to detect this image difference by image processing, and for example, it can be detected by a process of counting the number of bright or dark portions having an area of a certain area or less.

    FIG. 6 is a diagram showing a measurement flow of the eccentricity measuring apparatus not provided with the rotation detection unit of the present invention. An object to be measured was set, the rotation mechanism was set and driven, the eccentricity was measured, and a pass / fail judgment was made based on the result. In this case, if the eccentricity is very small, it is determined as defective, and the non-defective product is excluded. FIG. 7 shows a measurement flow of the eccentricity measuring apparatus provided with the rotation detection unit of the present invention. A rotation detection step is interposed between the step of driving and driving the rotation mechanism and the step of measuring the eccentricity, and laser light ON / OFF and non-rotation case processing are added. Laser light can be turned on and off by turning the laser power on and off, but if it is frequently turned on and off, a mechanical shutter or the like is used. In the case of non-rotating, it is assumed that there is a foreign object between the object to be measured and the V-groove, or the contact state with the rotating mechanism is insufficient. If the rotating mechanism is reset, for example, foreign matter is removed by returning it to the initial state and contacting it again, the rotating mechanism often rotates. The processing to be performed is added. Furthermore, the rotation mechanism may be rotated in the reverse direction, or the object to be measured may be removed from the base and a cleaning mechanism may be applied to reset the object to be measured.

It is a figure which shows the outline | summary of the eccentricity measuring apparatus which is not equipped with the rotation detection part of this invention. It is a figure which shows the example of the image of the hole image | photographed with the camera. It is a figure which shows the outline | summary of the eccentricity measuring apparatus provided with the rotation detection part of this invention. It is a figure which shows the example image | photographed with the camera 5 when not rotating. It is a figure which shows the example image | photographed with the camera 5 when rotating. It is a figure which shows the measurement flow of the eccentricity measuring apparatus which is not provided with the rotation detection part. It is a figure which shows the measurement flow of the eccentricity measuring apparatus provided with the rotation detection part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Object to be measured 2 ... Base 3 ... Rotating mechanism 4 ... Illuminating device 5 ... Camera 6 ... Image processing inspection apparatus 7 ... Hole 8 ... Outside part of hole 9 ... Semiconductor laser projector 10 ... Semiconductor laser beam 11 ... Tint

Claims (4)

In a device that takes a hole image with a camera while rotating the hollow cylinder and the eccentricity of the hole and the outer periphery of the hollow cylinder, and measures the amount of eccentricity from the change of the position of the hole image, the hollow cylinder is irradiated with laser light and laser light An eccentricity measuring apparatus comprising means for detecting the presence or absence of rotation based on a change in optical speckle due to. 2. The eccentricity measuring apparatus according to claim 1, wherein the hollow cylinder is irradiated with laser light, an optical speckle image by the laser light is photographed by a camera, and the presence or absence of rotation is detected from the speckle image. 3. The eccentricity measuring apparatus according to claim 2, wherein the camera that captures the optical speckle image by the laser beam is the same as the camera that captures the hole image for the eccentricity measurement. 4. The eccentricity measuring apparatus according to claim 2, wherein the presence or absence of rotation is detected by performing image processing on an optical speckle image by the laser beam.