KR100269263B1 - Microhole straightness measurement system with 3 precision moving stage - Google Patents

Abstract

PURPOSE: An apparatus for measuring straightness of minute holes is provided to widen a geometric measurement field of a ferrule for an optical connector by allowing the straightness within holes having a micro capillary structure to be measured. CONSTITUTION: An apparatus for measuring straightness of minute holes includes a micromirror lens(1) for measuring the straightness of micromirror holes and a CCD camera(2) to which numerous unit cells are attached. A 3-axis fine driving stage includes a Z axis driving stage(3) for controlling the focus of the micromirror lens(1) included in the CCD camera(2). A computer has an A/D converter for converting analog signals generated by the unit cells of the CCD camera(2) in proportion to the intensity of light into digital signals. A back illumination device is installed below a stage to which a measurement sample is mounted.

Description

Apparatus and method for measuring straightness of micro holes using non-contact optical system

The present invention maintains the optical fiber. The present invention relates to an apparatus and a method for measuring the straightness of a fine hole using a non-contact optical system, which measures the straightness of the cylindrical fine hole inside the ferrule for single-core and multi-core optical connectors used for alignment.

In the conventional method, a lot of researches have been made on micro holes having a very small diameter, but little is known about the inside of the hole, that is, the hole straightness.

Optical connector ferrules for the support of optical fibers are typically penetrated from 8 mm to 13 mm, with a short hole of 125 to 127 μm in the structure to maintain the shorted optical fiber.

This micro hole must ensure the straightness of the penetrated cylindrical micro hole because of the necessity of keeping the fiber straight.

If the straightness of the microtube is not guaranteed, there is a high possibility of micro bending loss of the optical fiber.

Normally, the straightness of the hole is obtained by inserting the sensor into the tube to find the geometric surface of the inner wall and comparing it with the ideal straight line to calculate the deviation.However, in the case of the optical hole, the diameter of the optical connector is only about 0.127mm. This is practically absent.

To solve this problem, the measurement target is placed on a flat stage, and then a cylindrical microtube is mounted using a CCD camera equipped with a high magnification microscope lens located opposite the hole while being incident on the microhole at a constant light intensity using an illuminant illumination. When interpreting the past image, if the straightness of the workpiece is excellent, the electric value corresponding to the light intensity of the CCD element will have a constant distribution, otherwise it will be shaded and the electric value of the element in the CCD will be uneven. .

It is difficult to measure the straightness of such micro holes because the diameter is too small for the length (diameter = 98.4 times the length), and it is difficult to measure the conventional method.

In the existing method, the contact sensor is inserted into the cylindrical hole to find the structure inside the object to be measured or the sensor that can be inserted into the diameter of 0.127 mm has not been developed until now.

To this end, we propose a measuring device and method using a non-contact optical system.

The present invention maintains the optical fiber. It is an object of the present invention to provide an apparatus and method for measuring the straightness of a microhole using a non-contact optical system as a method of measuring the straightness of a cylindrical microhole in an ferrule for an optical connector used for alignment.

1 is a non-contact optical measurement system composed of a precision three-dimensional drive stage capable of flatly fixing the specimen according to the present invention.

2 is a schematic diagram of a system of the present invention.

Figure 3 is a configuration of the illumination device for sending light into the specimen and the hole placed on a flat stage.

4 is a flow chart for calculating hole straightness

* Explanation of symbols for the main parts of the drawings

1: microscope lens 2: CCD camera

3: Z-axis drive stage 4: Y-axis drive stage

5: X axis drive stage 6: coaxial cable

7: A / D converter 8: computer

9: Test Specimen 10: Stage

11: luminaire lighting system

In order to achieve the above object, in the present invention, the system is equipped with a three-dimensional precision transfer stage having an excellent flatness for placing the specimen and the illumination illuminator, a microscope lens and a number of units to measure the straightness of the micro holes A CCD camera with a cell attached thereto; A three-axis precision moving stage including a Z-axis driving stage for adjusting a focus of a microscope lens provided in the CCD camera; A computer equipped with an A / D converter for digitally converting an analog signal generated by a unit cell of the CCD camera in proportion to light intensity; Comprising an emission illumination device installed on the lower side of the stage on which the specimen is mounted, the three-axis precision moving stage and the Z-axis driving stage for adjusting the focus of the microscope lens; An X-axis drive stage and a Y-axis drive stage for precisely adjusting the X-axis displacement and the Y-axis displacement with respect to the measurement specimen is characterized in that the configuration.

In addition, the present invention by applying a non-contact optical measurement system and a high-resolution CCD camera driven by a precision moving stage to the light emitted from the irradiation light to reach the CCD camera with a high number of pixels (pixels) through the microscope lens, the CCD camera Specimens are transmitted by transmitting analog electrical signals representing voltages proportional to the light intensity by hundreds of thousands to millions of unit cells to a computer that digitalizes them by the A / D converter to interpret the image emitted from the upper hole. The straightness is measured by calculating the straightness of the workpiece based on the image shade of the upper hole due to the internal curvature and the deviation value of the intensity of the electric charge corresponding to these shades.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In general, the straightness of the structure penetrating the top and bottom sets the baseline (line segment perpendicular to the top and bottom of the workpiece) and measures the inside of the actual structure to obtain the straightness by comparison with the baseline.

That is, the contact sensor is inserted into the object to be measured to find out the internal phenomenon and the degree of bending and to compare it with the reference line.

FIG. 1 shows a non-contact optical measurement system composed of a precision three-dimensional driving stage capable of flatly holding a specimen, and FIG. 2 is a schematic configuration diagram of the system of the present invention.

At the end of the Z-axis drive stage 3, a CCD camera 2 is attached to observe the cylindrical micro-holes using the light emitted from the illumination illuminator 11, and the observed analog image data is grabber in the computer 8 for analysis. It is connected to the board where the analog data is digitized to calculate the shadow area of the whole hole.

FIG. 3 shows a measuring specimen 9 placed on a flat stage 10 and an illumination illuminating device 11 for sending light into the hole. FIG. 4 shows a hole straightness calculation flowchart according to the present invention.

Since the measurement target has a very small diameter compared to the length, it is difficult to secure a space for inserting and operating a position change detection sensor. Therefore, a non-contact optical measuring system and a high resolution CCD camera (2) driven by a precision moving stage are used for this purpose. .

That is, the light emitted from the illuminating illuminator 11 reaches the CCD camera 2 having a high number of pixels (pixels) on which the microscope lens 1 is mounted.

Of course, the Z-axis driving stage 3 is required for focusing the microscope lens 1.

The CCD camera (2) has hundreds of thousands to millions of unit cells, which represent voltage in proportion to the intensity of light. These electrical signals are analog signals and are equipped with A / D converters for digital signalization. Is transferred to the computer 8.

The conversion signal to digital will be able to interpret the image emitted from the top hole.

If the initial specimen was enlarged 1000 times (lens magnification × CCD magnification), the result would be a circular 12.7 cm diameter.

If there is an internal curvature, the image of the upper hole will be shaded, and the charge intensity corresponding to these shades will be low, and the charge intensity corresponding to the entire cell will show a large deviation (max-min) value. In other words, the straightness of the workpiece can be calculated.

The calculable measure is

Maximum value-Minimum Value

The standard deviation of each cell, the deviation of the standardized cell, and the like can be considered.

Ideally, if straightness is perfect, the deviation will be zero.

Through the present invention, since it is possible to measure the straightness inside the hole having the microcapillary structure, the optical connector ferrule can be secured while at the same time securing the technology for expanding the geometric measurement field of the ferrule for the optical connector having the most microcapillary structure. Internal micro-bending loss can be reduced.

Claims (3)

A microscope camera 1 and a CCD camera 2 to which a number of unit cells are attached to measure the straightness of the micro holes; A three-axis precision drive stage including a Z-axis drive stage (3) for adjusting the focus of the microscope lens (1) provided in the CCD camera (2); A computer (8) equipped with an A / D converter for digitally converting an analog signal generated by a unit cell of the CCD camera (2) in proportion to light intensity; A device for measuring the straightness of a fine hole using a non-contact optical system composed of an illumination illuminator 11 installed below the stage 10 on which the measurement specimen 9 is mounted. The method of claim 1, The three-axis precision moving stage includes a Z-axis driving stage (3) for adjusting the focus of the microscope lens (1); Straightness measurement of microholes using a non-contact optical system, characterized in that it consists of an X-axis drive stage 5 and a Y-axis drive stage 4 for precisely adjusting the X-axis displacement and the Y-axis displacement with respect to the measurement specimen (9) Device. By applying a non-contact optical measuring system and a high-resolution CCD camera driven by a precision moving stage, the light emitted from the illumination light reaches the CCD camera having a high pixel count through the microscope lens. The CCD camera transmits an analog electrical signal representing a voltage in proportion to the light intensity by hundreds to millions of unit cells to a computer that digitalizes the signal by an A / D converter to interpret an image emitted from the upper hole. The straightness of the workpiece is calculated from the image shade of the top hole due to the curvature inside the specimen and the deviation value of the intensity of the charge corresponding to these shades. Straight hole measurement method using a non-contact optical system, characterized in that for measuring.

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