JPH05118831A - End-face inspecting apparatus for optical connector - Google Patents

Abstract

PURPOSE:To prevent the damaging of a convex spherical surface and to make it possible to measure the amount of and the radius of curvature of the spherical surface at the same time by generating Newton rings at the end face of an optical connector with an image focusing optical system including an interference objective lens provided at the position where the reference surface is separated with respect to the surface to be measured of the optical connector, and inspecting the shape of the edge. CONSTITUTION:The images of a Newton rings which are generated between a non-contact surface to be measured 2, i.e., the end face of an optical connector 1 and a reference surface 9, and the image of an optical fiber 3 are picked up with an interference objective lens 5. The image information is latched with an image sensing means 10 at the same time. The image information is analyzed, and the individual interference fringe is discriminated with an interference discriminating means 21. The center and the diameter of the ring are obtained with a ring-center detecting means 22 and a ring-diameter detecting means 24. A decentering amount E and a radius of curvature R are obtained with a amount detecting means 23 and a radius-of-curvature detecting means 25 without damaging the fiber edge 2 under the state, wherein the reference surface 9 is separated from the object to be measured 2. The image information, wherein the optical fiber 3 and the Newton rings are contained on the same XY coordinates, is obtained, and the amount E and the raius of curvature R can be measured at the same time in one measurement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting an end face shape of an optical connector used for connecting optical fibers to each other. More specifically, the present invention is an optical connector for measuring the radius of curvature of a spherically processed tip surface of an optical connector composed of an optical fiber and a ferrule holding the optical fiber and the eccentric amount of a convex spherical surface with respect to the optical fiber. End face inspection device.

[0002]

2. Description of the Related Art An optical fiber and an optical connector having a ferrule holding the optical fiber whose end surface is processed into a convex spherical surface can reduce reflected light at a connector connecting point and reduce connection loss. However, it is important to reduce the amount of eccentricity of the convex spherical surface with respect to the optical fiber centered on the ferrule in order to reliably reduce the connection loss of both. Therefore, a device for accurately measuring and evaluating the amount of eccentricity is required. Further, a device for detecting and evaluating whether or not the convex spherical surface of the ferrule tip surface has a radius of curvature satisfying the standard is also required.

Conventionally, as a method of evaluating the amount of eccentricity of the end face of the optical connector, there is a method of pressing an optical flat or glass plate against the end face of the ferrule to generate interference fringes for evaluation (Japanese Patent Laid-Open No. 62-106337). ). As shown in FIG. 5, this end face inspection apparatus is provided with a front end face 1 of a ferrule 101.
Glass plate 10 arranged at a right angle to the optical fiber 103.
4 is pressed, and the eccentric amount E between the center of the Newton ring, that is, the center of the convex spherical surface 102 and the center A of the ferrule 101 generated around the point B that contacts the glass plate 104 is obtained.

As a method of measuring the radius of curvature of the tip surface of the spherical ferrule, it has been customary to draw a cross-sectional profile of the apex with a stylus type roughness meter or shape measuring instrument and then calculate it. there were.

[0005]

However, since the glass plate 104 is pressed against the tip surface of the ferrule 101 to generate the Newton's ring 105, the end surface of the optical fiber 103 at the center A of the ferrule 101 may be damaged. There is. In the drawing disclosed in Japanese Patent Laid-Open No. 62-106337, the tip surface 102 of the ferrule 101 is exaggeratedly drawn, so that the glass plate 104 is separated from the end surface of the optical fiber 103. However, the ferrule is manufactured by the ferrule. Since the amount of eccentricity of the optical fiber 103 with respect to 101 is controlled to be within several tens of μm at most, the tip end surface of the optical fiber 103 does not come into contact with the glass plate 104. Further, when the glass plate 104 is dirty or scratched, a sufficiently clear interference fringe image necessary for measurement cannot be obtained. Therefore, the glass plate 10 serving as the reference surface
4 is frequently required, and the scratched glass plate 104 needs to be replaced regularly. Further, since the Newton ring 105 is generated around the contact point B between the glass plate 104 and the ferrule tip surface 102,
The eccentric amount E may change apparently by one pressing method of the glass plate 104, and may deviate from the actual ferrule tip surface 102, that is, the center B of the convex spherical surface.

Moreover, since the apparatus shown in FIG. 5 can measure only the eccentricity E, the radius of curvature R of the distal end surface 102 must be measured together with another radius of curvature R, so that the inspection process is repeated. Will be needed.

In addition, in the conventional method of measuring the radius of curvature, there is a risk of scratching the ferrule tip surface 102 with a stylus. In addition, there is a problem that the measurement takes time or the calculation points are limited and the reliability of the measurement result becomes low. Also,
It is possible to calculate the radius of curvature of the spherical surface as a part of the function of the laser interferometer using a very large-scale laser interference principle that has another application, but it is too expensive for the equipment cost. Not at all.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an end face inspection device for an optical connector which does not need to be regularly and frequently replaced in order to prevent or damage the convex spherical surface due to dirt on the reference surface. Further, the present invention provides an end face inspection device for an optical connector, which can simultaneously measure either one or both of the eccentricity amount and the radius of curvature of the spherical surface from the image information obtained by one measurement, if necessary. The purpose is to

[0009]

In order to achieve the above object, the present invention inspects the end face shape of an optical connector in which an optical fiber is penetrated and fixed at the center of a ferrule and the end faces of which are processed into a convex spherical surface. In the device, a Newton's ring is generated on the tip surface of the optical connector by using an imaging optical system including an interference objective lens provided at a position where a reference surface is separated from the surface to be measured of the optical connector, and this is used. The end face shape is inspected.

In the end face inspection apparatus of the present invention, the tip end surface of the optical connector is passed through an imaging optical system including an interference objective lens provided at a position where the reference surface is separated from the measurement target surface of the optical connector and the interference objective lens. An image pickup means that captures the image of the Newton ring and the optical fiber formed as image information as image information, an interference fringe determination means that analyzes this image information to determine an interference fringe, and a ring center detection means that calculates the Newton ring center, And an eccentricity amount detecting means for obtaining an eccentricity amount with respect to the center of the optical fiber with respect to the center of the ring.

Further, the end face inspection apparatus of the present invention comprises an imaging optical system including an interference objective lens provided at a position where the reference surface is separated from the measurement target surface of the optical connector, and the tip of the optical connector through the interference objective lens. Image pickup means for taking in images of Newton rings and optical fibers formed on the surface as image information, interference fringe discrimination means for discriminating interference fringes by analyzing this image information, and ring diameter detection means for obtaining the diameter of each Newton ring And a radius-of-curvature detecting means for obtaining the radius of curvature of the convex spherical surface from the diameter of the Newton's ring.

In the end face inspection apparatus of the present invention, the tip end face of the optical connector is passed through an imaging optical system including an interference objective lens provided at a position where the reference surface is separated from the measurement target surface of the optical connector, and the interference objective lens. An image pickup means for taking in the image of the Newton ring and the optical fiber formed as image information as image information, an interference fringe discriminating means for discriminating the interference fringe by analyzing the image information, and a ring diameter detecting means for obtaining the diameter of each Newton ring. A ring center detecting means for calculating a Newton ring center, an eccentricity detecting means for obtaining an eccentricity amount of the ring center with respect to the center of the optical fiber, and a radius of curvature detecting for obtaining a radius of curvature of the convex spherical surface from a diameter of the Newton ring. And means.

[0013]

Therefore, the interference objective lens images the non-contact measurement target surface, that is, the Newton's ring generated between the end surface of the optical connector and the reference surface, and simultaneously captures it as image information. Since the image information includes the optical fiber and the Newton's ring on the same XY coordinates, the distance between them, that is, the eccentricity E and the radius of curvature R of the convex spherical surface can be obtained. For example, as in the second aspect of the invention, the center of the Newton ring is calculated by determining the individual interference fringes and determining the diameter of the ring by combining the interference fringes belonging to the same ring. Therefore, the same X as the image information
An eccentric amount E of the center of the Newton's ring with respect to the center of the optical fiber which is simultaneously input to the Y coordinate is calculated. Further, as in the invention described in claim 3, the radius of curvature R of the convex spherical surface is obtained from the diameter of the Newton ring and the wavelength of the interference light. Furthermore,
In the invention of claim 4, the eccentric amount E and the radius of curvature R are simultaneously measured by one measurement.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a block diagram showing an embodiment of an end face inspection apparatus for an optical connector according to the present invention. This optical connector 1
The end face inspection apparatus of No. 2 uses a Newton's ring 28 by an image forming optical system 10 such as a microscope, which uses an interference objective lens 5 arranged in a non-contact manner with a reference surface 9 separated from the end surface (convex spherical surface) of the optical connector 1. Is generated and observed. The interference objective lens 5 mainly comprises an objective lens 6, a beam splitter 7, and a reference mirror 8 forming a reference surface 9.
And a position which is not in contact with the measurement target surface 2, for example, the measurement target surface 2 and the reference surface 9 are the beam splitter 7
At a position that is substantially equidistant from the center axis of the ferrule 4 on the surface 2 to be measured and is orthogonal to the center axis passing through the optical fiber 3, that is, parallel to the axis of the optical fiber 3. A reference mirror 8 is installed. This reference surface 9
And a beam splitter 7 provided between the measurement target surface 2 and
As a result, a part of the light is applied to the surface to be measured 2 and the remaining part is applied to the reference surface 9, causing interference due to the optical path difference between the respective reflected lights and generating the Newton ring 28.
The reference surface 9 must be arranged at a distance substantially the same as the distance from the beam splitter 7 to the measurement target surface 2 and orthogonal to the central axis passing through the center of the optical fiber 3. The reference surface mirror 8 is provided so that the reference surface mirror 8 can be tilted and its position can be adjusted in the front-rear direction with a screw or the like. Further, a CCD (charge coupled device) camera as the image pickup means 15 is installed in the image forming portion of the microscope 10 so as to take an image of the Newton's ring 28 and the optical fiber 3. For image input, A / D conversion is performed for each pixel of the CCD camera 15, which is an image pickup unit, and the interference fringes are converted into a grayscale image having a desired gradation, for example, 16 gradations.

On the other hand, the microscope objective part is provided with a support member for attaching the optical connector 1 to the microscope 10 and setting the measurement target surface 2 at a fixed position. For example, as shown in FIG. 2, this support member is composed of a fixed block 18 having a V groove 17 that contacts the outer peripheral surface of the ferrule 4 and a movable block 19 that presses the ferrule 4 against the fixed block 18.
The movable block is attached to the fixed block 18 so as to move toward and away from the fixed block 18 with the stopper pin 19a fixed to the fixed block 18 as a guide. The movable block 19 is constantly urged toward the fixed block 18 by a coil spring 19b mounted between the stopper pin 19a and the movable block 19, and holds the ferrule 4 with the fixed block 18. An eccentric cam 16b is rotatably attached to the movable block 19, and is provided so as to rotate the eccentric cam 16b by operating a knob 16a. On the other hand, the fixed block 18 includes a bracket 16 extending near the eccentric cam 16b.
Is stuck. When the eccentric cam 16b on the movable block 19 side rotates and comes into contact with the bracket 16, the movable block 19 separates from the fixed block 18 and releases the ferrule 4. The fixed block 18 is, for example, the microscope 1 that adjusts the distance between the measurement target surface 3 and the objective lens 6.
The fine adjustment means 0 is attached to the upper and lower stages, and is moved up and down by operating the knob 10a for adjusting the upper and lower stages to move the optical fiber 3 toward or away from the objective lens 6. Here, the supporting member is preferably provided so that the entire area of the ferrule 4 is not supported by the fixed block 18 but is supported by a small width of two points on the front end side and the rear end side.
In FIG. 1, reference numeral 11 is a half mirror, 12 is a condenser lens, 13 is a light source, and 14 is an imaging lens.

The image information obtained by the CCD camera 15 is sent to the image processing section 20, which discriminates the Newton's ring 28 and obtains the diameter and center of the ring, and then the eccentricity E with the optical fiber 3. Or the radius of curvature R of the surface to be measured, that is, the convex spherical surface 2 of the ferrule. The image processing unit 20 detects an interference fringe of the image data input through the image pickup unit 15, an interference fringe determination unit 21, a ring center detection unit 22 that calculates a ring center of the interference fringe, and a center of the optical fiber. An eccentricity amount detecting means 23 for obtaining an eccentricity amount E with respect to the ring center, and a ring diameter detecting means 24 for obtaining a ring diameter of the interference fringes,
A radius-of-curvature calculating unit 25 for obtaining the radius-of-curvature R of the convex spherical surface of the optical connector from the diameter, and is configured by a known computer and program software for controlling the computer. Although not specifically shown, the computer generally has a ROM for storing control programs and the like, and a RAM for storing image data and input data relating to the optical fiber position.
And at least one CPU (central processing unit) and an I / O interface for connecting this CPU to a keyboard 26 which is an input device, a display 27 which is a display means for outputting a calculation result, a printer or the like.

The interference fringe discriminating means 21 recognizes bright fringes or dark fringes from the image data, for example, as shown in FIG.
As shown in, the image data is scanned on a certain straight line that intersects with the Newton ring 28, and the ring group is grasped as a continuous change in density / brightness / darkness, that is, a wave. When a difference is generated, it is determined that the change in density is caused by the interference fringes, and the density change below that is determined as noise, and the interference fringes are determined. Regarding the distinction between one interference fringe and the interference fringe next to it, one or more effective density changes due to the interference fringes exist in the same direction (for example, in the increasing direction of the density), and then the effective density change occurs. There is one or more effective density changes in the opposite direction (in the direction of decrease in density) in the same direction after passing the non-existing part, and one interference fringe is completed when there are no more effective density changes. Judgment is made, and the effective density change in the increasing direction that appears next is distinguished from that due to adjacent interference fringes.

The ring diameter detecting means 24 determines the diameter of one or more rings in the ring group. Further, the ring center detecting means 22 obtains the center B of each ring of the Newton ring 28. In the case of this embodiment, the diameter of each ring group is obtained and at the same time the coordinates of the center point are obtained. .. For example, in the area determined to be the same fringe by the interference fringe determination means 21, two points having the same brightness are selected, the center thereof is determined as the center of the stripe of the interference fringe, and the centers of the fringes belonging to the same ring are further determined. The diameter of each ring is obtained by determining the combination, the distance between them, and the center of each ring is obtained by determining the center point between the two points. Specifically, in this embodiment, two points s ₁ and t ₁ having the same brightness on a certain straight line are selected in the area determined by the interference fringe determination means 21 to have the same fringe and the center a ₁ thereof is selected. Is obtained as the center of the stripe of the interference fringe, and similarly, the other center b ₁ of the fringes belonging to the same ring is obtained, a large number of these a ₁ and b ₁ are combined, and the distance between two points (a ₁ .B ₁ ), the average center Q is obtained from the center points Q ₁ , Q ₂ , ..., Q _n , and passes through the center point Q and belongs to the same ring on a straight line orthogonal to the previous straight line. From the centers c ₁ and d ₁ , c ₂ and d ₂ , ..., C _n and d _n of the two points of the stripe, the center points B ₁ , B ₂ , ..., B _n between these two points are obtained and averaged. Gives the center of the ring. That is, in this embodiment, the center of the ring (the center of the ring) is calculated after the diameter of the ring is calculated, and the ring diameter detection means 24 and the ring center detection means 22 share a part of the configuration.

The eccentricity detecting means 23 obtains the eccentricity E of each of the center A of the optical fiber 3 and each ring center point B obtained by the ring center detecting means 22 and then calculates the average value thereof. Then, it is obtained from the difference between the position A of the optical fiber which is captured as image data together with the Newton ring and specified on the XY coordinates in advance, and each ring center B calculated by the ring center detecting means 21.

The radius-of-curvature detecting means 25 determines the radius of curvature R of the front end face of the optical connector from the diameter of any ring in the ring group and the wavelength of the reflected light. The calculation of the radius of curvature R is easily obtained by obtaining the ring radius because the wavelength λ of the light generated by the Newton ring 28 is known in advance. For example, when the bright ring of the Newton ring 28 by one reflected light is used, it is calculated by the following formula 1.

[0022]

[Equation 1] (However, m indicates the ring number from the center (m = 0).) When a plurality of Newton rings 28 appear, any two rings are extracted from them. The radius of curvature R can be obtained by comparing the relative radii. That is, the ring of light having the wavelength λ appears at each step λ / 2 on the spherical surface, and therefore, for example, when two adjacent fringes are compared, it is obtained by the mathematical formula 2.

[0023]

[Number 2] R = - when comparing the two stripes flying ^{_{{(r i + 1) 2}} (r i) 2} / λ 1 This fringe is given by Equation 3.

[0024]

Equation 3] R = - when {the ^{_{(r i + 2) 2 (}} r i) 2} / 2λ further compare the two stripes away the n is determined by Equation 4.

[0025]

## EQU4 ## R = {(r _{i + n} ) ² − (r _i ) ² } / nλ The above-mentioned embodiment is an example of the preferred embodiment of the present invention, but the present invention is not limited to this. Various modifications can be made without departing from the spirit of the invention. For example, the interference objective lens 5 is not particularly limited to the one shown in the figure, and the light source 13 and the reference surface 9 may be provided via a Milo interferometer in which the reference surface 9 is installed on the same optical axis in parallel with the measurement target surface 2 or a half mirror. It can also be implemented by a Linic interferometer in which and are opposed to each other.

According to the end face inspection apparatus for an optical connector of the present embodiment having the above-mentioned configuration, the calculation of the eccentricity E and the convex spherical curvature radius R is executed based on the flow charts shown in FIGS. 4 and 5, for example. It

First, as a preparatory step, the optical connector 1 is held between the fixed block 18 and the movable block 19 of the supporting member of the microscope 10 which is an image forming optical system. Then, the upper and lower stage adjustment knobs 10a are operated to move the optical connector 1 along with the fixed block 18 and the movable block 19 in the optical axis direction to generate the Neutling 28, for example, two or more dark stripes or bright stripes are generated. To adjust.

Next, the image of the Newton ring 28 is input (step 31). Image input is CCD as an imaging means
A / D conversion is performed for each pixel of the camera 15, and the interference fringes are converted into, for example, a grayscale image with 16 gradations and stored. Then
The center position A of the optical fiber 3 in the XY coordinates is input by viewing the image pickup screen in the XY coordinates (step 32). For example, the keyboard 26 is operated while looking at the display to move the cursor to the center of the optical fiber 3 to read the coordinates and store the coordinates. Further, it is determined whether the input image data is an interference fringe (step 33). For example, a memory image is scanned on a certain straight line set in advance and captured as a wave of light and dark. For example, when the densities adjacent to one pixel have a difference of three or more gradations, it is determined that the density changes due to interference fringes,
The interference fringes are discriminated by discriminating the density change below that as noise. Regarding the distinction between one interference fringe and the interference fringe next to it, one or more effective density changes due to the interference fringes exist in the same direction (for example, in the increasing direction of the density), and then the effective density change occurs. There is one or more effective density changes in the opposite direction (in the direction of decrease in density) in the same direction after passing the non-existing part, and one interference fringe is completed when there are no more effective density changes. Judgment is made, and the effective density change in the increasing direction that appears next is distinguished from that due to adjacent interference fringes.

Next, a combination of interference fringes belonging to the same ring is obtained as shown in FIG. First, the centers a ₁ , a ₂ , ..., P, b ₁ , b _2, ..., B _n of the interference fringes are obtained (step 34). This can be obtained, for example, by defining the center of two points S ₁ and t ₁ having the same brightness in the area determined to have the same fringe in step 33 as the center a _{1 of the} interference fringe. Specifically, pixels having the same gray scale are searched for in the same stripe, and the center between the pixels is set as the center of the interference fringe.
Similarly, the respective center points a ₂ , a ₃ , ..., P, b ₁ , b ₂ , ... Of the interference fringes forming the other Newton's rings are obtained. Next, a combination of interference fringes belonging to the same ring is obtained (step 35). As is clear from FIG. 3, the distance (a ₂ ·
_{a 3), (a 1 ·} a 2), (P · a 1), (P ·
When b ₁ ), (b ₁ · b ₂ ) is calculated, (P · a ₁ ) =
(P · b ₁ ) = maximum (P · a ₁ )> (a ₁ · a ₂ )>
It can be seen that it becomes (a ₂ · a ₃ ). From this, a ₁
And b ₁ are judged to be on the same ring and are combined. Next, an arbitrary ring, for example, between innermost rings a ₁ and b ₁
Find the center point to Q _1, Similarly a _2, b ₂ from Q _2,
a _3, b ₃ from Q _3, ..., determine the Q _n, obtains the average center Q from the average of their coordinates (step 36). However, Q may overlap with P, but it does not always match. At this time, a straight line passing through Q and forming a right angle with the scanning direction in step 33 can be regarded as an average position across the center of the ring group. Therefore, the Newton ring 28 is passed again in the direction passing through Q and forming a right angle with the scanning direction in step 33.
Are scanned (step 37). And step 34-
36 in the same manner as in the center (i.e. peak or center of the trough of the wave) c _1, c ₂ of each of the interference _{fringes, ..., B 0, d 1} , d 2, ..., d n
(Step 38), the center point c on the same ring
₁ and d ₁ , c ₂ and d ₂ , ..., C _n and d _n are combined (step 39), and the distances (c ₁ · d ₁ ) and (c ₂ between the centers of the interference fringes on the same ring are calculated. .D ₂ ), ..., (C _n · d
_n ) is obtained (step 40). At this time, since the straight line to be scanned passes through the center of the string crossing the point Q, that is, the Newton's ring 28 determined in steps 33 to 36 and is orthogonal to the string, it intersects the center of the ring group. You have determined the diameter of the ring.

Next, the eccentricity E and the radius of curvature R of the convex spherical surface
Calculate. The calculation of the amount of eccentricity E is carried out in steps 37 to 40. The center point B ₁ between the center points c ₁ and d ₁ of the interference fringes on the same ring (that is, the ring center) B ₁ and the center point B between c ₂ and d _2.
The coordinates of the central point B _n of ₂ , ..., C _n and d _n on the XY coordinates are obtained (step 41). Next, each central point B
, B _n and the distance E ₁ , E ₂ , ..., E _n between the fiber center position A and ₁ , B ₂ ,.
2). The distance E _1, E ₂ between the optical fiber center A of each ring, ..., averaged center or convex spherical surface and the center B of the optical fiber center A and Newton ring 28 on average E _n The eccentricity amount E is obtained (step 43). The eccentricity amount E obtained in step 43 is displayed on the display (step 44).

The radius of curvature R of the convex spherical surface 2 can be calculated by finding the ring radius because the wavelength λ of the light generated by the Newton ring 28 is known in advance. Distances between center points (c ₁ · d ₁ ), (c ₂ · d ₂ ), ..., (c _n · d _n ) obtained in step 40
That is, the diameter of each ring is divided into two to obtain the radius of each ring (step 45). Then, the radius of curvature R is calculated from the value of each ring radius using two arbitrary radii (step 46). In this case, any two adjacent bright stripes are extracted, and the radius of curvature R is obtained by comparing their relative radii according to Equation 5.

[0032]

R = {(r _{i + 1} ) ² − (r _i ) ² } / λ Next, the radius of curvature R obtained in step 46 is displayed on the display (step 47). Then, the process ends with return (step 48).

[0033]

As is clear from the above description, the end face inspection apparatus for an optical connector according to the present invention is a Newton's ring generated between the non-contact measurement target face, that is, the end face of the optical connector and the reference face by the interference objective lens. Since the optical fiber and the optical fiber are picked up and captured as image information at the same time, the eccentricity E and the radius of curvature R can be obtained without separating the reference surface from the surface to be measured and damaging the fiber end surface. Moreover, the contamination of the surface to be measured does not adhere to the reference surface, so that the reference surface needs to be frequently cleaned or the reference surface needs to be regularly replaced.

Further, according to the end face inspection apparatus of the present invention, the image information in which the optical fiber and the Newton's ring are taken in on the same XY coordinate is obtained, and the eccentricity E and the radius of curvature R are obtained using this image information. Therefore, the amount of eccentricity and the radius of curvature can be measured at the same time with one measurement, and the measurement process can be simplified.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of an end face inspection device for an optical connector of the present invention.

2 is a schematic explanatory view of a microscope objective section in the system configuration of FIG. 1, where (A) shows an interference objective lens and (B) shows a support member.

FIG. 3 is an explanatory diagram of a method for obtaining a diameter and a center of a Newton ring.

FIG. 4 is a part of a flowchart of the end face inspection apparatus for an optical connector of the present invention.

FIG. 5 is a continuation of the flowchart of the end face inspection apparatus for an optical connector of the present invention.

FIG. 6 is a schematic diagram showing an inspection method of a conventional optical connector end face inspection apparatus.

[Explanation of symbols]

 1 Optical Connector 2 Measurement Target Surface 3 Optical Fiber 4 Ferrule 5 Interference Objective Lens 9 Reference Surface 10 Imaging Optical System 15 Imaging Means 18 Fixed Block That Supports Ferrule 19 Movable Block That Supports Ferrule 21 Interference Pattern Discrimination Means 22 Ring Center Detection Means 23 Eccentricity Detecting Means 24 Ring Diameter Detecting Means 25 Curvature Radius Detecting Means 28 Newton's Rings

Claims (4)

[Claims] 1. An apparatus for inspecting an end face shape of an optical connector in which an optical fiber is penetrated and fixed at the center of a ferrule and the end faces of which are processed into a convex spherical surface, a reference surface is provided with respect to a surface to be measured of the optical connector. An end face of the optical connector is characterized in that a Newton's ring is generated on the end face of the optical connector by an imaging optical system including an interference objective lens provided at a separated position, and the end face shape is inspected by this. Inspection equipment. 2. An apparatus for inspecting an end face shape of an optical connector in which an optical fiber is penetrated and fixed at the center of a ferrule and the end faces of which are processed into a convex spherical surface, a reference surface is provided with respect to a surface to be measured of the optical connector. An image forming optical system including an interference objective lens provided at a separated position, an image pickup means for taking in an image of a Newton's ring and an optical fiber formed on the front end surface of the optical connector through the interference objective lens as image information, and the image information. And an eccentricity amount detecting means for obtaining an eccentricity amount with respect to the center of the optical fiber with respect to the center of the optical fiber. Characteristic optical connector end face inspection device. 3. An apparatus for inspecting an end face shape of an optical connector in which an optical fiber is penetrated and fixed to the center of a ferrule and the end face of which is processed into a convex spherical surface, a reference face is provided with respect to a measurement target face of the optical connector. An image forming optical system including an interference objective lens provided at a separated position, an image pickup means for taking in an image of a Newton's ring and an optical fiber formed on the front end face of the optical connector through the interference objective lens as image information, and this image It comprises interference fringe discrimination means for analyzing information and discriminating interference fringes, ring diameter detection means for obtaining the diameter of each Newton ring, and curvature radius detection means for obtaining the radius of curvature of the convex spherical surface from the diameter of the Newton ring. An end face inspection device for optical connectors. 4. An apparatus for inspecting an end face shape of an optical connector in which an optical fiber is penetrated and fixed at the center of a ferrule and the end faces of which are processed into a convex spherical surface, and a reference surface is provided with respect to a surface to be measured of the optical connector. An image forming optical system including an interference objective lens provided at a separated position, an image pickup means for taking in an image of a Newton's ring and an optical fiber formed on the front end surface of the optical connector through the interference objective lens as image information, and the image information. Of the interference fringe discriminating means for discriminating the interference fringes, the ring diameter detecting means for obtaining the diameter of each Newton ring, the ring center detecting means for calculating the Newton ring center, and the ring center with respect to the center of the optical fiber. Eccentricity amount detecting means for obtaining the amount of eccentricity and curvature radius detecting means for obtaining the radius of curvature of the convex spherical surface from the diameter of the Newton's ring An end face inspection device for an optical connector, comprising: