JPH08233545A - Hole shape measuring method and measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a hole shape measuring method and a measuring apparatus capable of non-contact and highly accurately measuring a hole shape having a relatively small diameter. [Structure] Light emitted from a light source 4 passes through a filter 6, a slit 7 and a projection objective lens 8 along an optical axis 5, and an image of the slit 7 is formed on a wall surface of the small diameter hole 1. The linear slit 7 is opened perpendicularly to the paper surface. The slit light reflected by the wall surface of the small diameter hole 1 is received by the light receiving objective lens 9
Thus, it is formed as an arc-shaped image on a two-dimensional image pickup device (not shown) in the camera 10. The image of the slit light is observed on the monitor screen, and the position of the stage 3 is adjusted so that the image forming position of the slit light and the measurement surface on the wall surface of the small diameter hole 1 coincide with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hole shape measuring method and a hole shape measuring apparatus for measuring a hole having a relatively small diameter. The measurement target is, for example, a small-diameter hole such as a die used for coating an optical fiber with a resin or a wire drawing die for manufacturing a metal wire.

[0002]

2. Description of the Related Art Conventionally, an optical method using a reticle is used as a method for measuring an inner diameter of a small diameter in which a probe cannot be inserted not only at the edge of the small diameter hole but at an arbitrary position on the cylindrical surface of the small diameter hole. Is used.

FIG. 6 is an explanatory view for explaining a conventional small-diameter inner diameter measuring device. In the figure, 1 is a small diameter hole, 2 is an object to be measured,
3 is a mounting stage, 4 is a light source, 5 is an optical axis, 51 is a light source reticle, 8 is a projection objective lens, 9 is a receiving objective lens, 1
Reference numeral 0 is a camera, 11 is a linear encoder, and 52 is an eyepiece reticle. The inner diameter measuring device is a device for measuring the inner diameter of the small diameter hole 1 by measuring an arbitrary position on the wall surface of the small diameter hole 1 provided in the object to be measured 2.

The light from the light source 4 illuminates the light source reticle 51 along the optical axis 5. The light source reticle 51 has a cross-shaped black index centered on the optical axis 5 of the light source provided on a transparent glass plate. In FIG. 6, one black line of the cross is provided in the direction perpendicular to the paper surface, and the other black line is provided in the vertical direction of the paper surface. The light transmitted through the light source reticle 51 is projected onto the one wall surface of the small diameter hole 1 by the light source prism (not shown), the projection objective lens 8 and the like.
The index of 1 is imaged and reflected. The position where the index is formed corresponds to the focal position of the projection objective lens 8, and the formed image is minute. The DUT 2 having the small diameter hole 1 is fixed to the stage 3 with the axial direction of the small diameter hole 1 in the left-right direction in FIG. On the light receiving side, the light receiving objective lens 9 forms a reflected image as a real image on a two-dimensional image pickup device in the camera 10, for example, a CCD sensor. When observing the reflected image with the naked eye, an eyepiece lens (not shown) is used instead of using the camera 10.

An eyepiece reticle 52 is provided behind the light receiving objective lens 9 in order to observe the image forming position of the index of the light source reticle 51. The eyepiece reticle 52 has a black mark line composed of two vertical lines provided on a transparent glass plate. The marked line of the eyepiece reticle 52 is also formed as a real image on the image pickup element in the camera 10. Alternatively, it is formed as a virtual image by an eyepiece lens (not shown). In FIG. 6, the marked line is provided in a direction perpendicular to the paper surface with the optical axis 5 of the light source as the center. The eyepiece reticle 52 may be provided inside the lens barrel of the eyepiece lens.
Instead of providing 2, the same marked line may be provided on the monitor screen of the image captured by the camera 10.

In the reflection image from the small diameter hole 1, the wall surface of the small diameter hole 1 can be observed as an unclear bright / dark boundary. In this case, when the optical axis 5 of the light source 4 connecting the centers of the light projecting objective lens 8 and the light receiving objective lens 9 and the wall surface of the small diameter hole 1 to be measured coincide, the reflected image of the index of the light source reticle 51 is It is observed as a dark line at the center of the two marked lines of the eyepiece reticle 52, that is, on the optical axis of the light source. When the index of the light source reticle 51 is separated in the X direction perpendicular to the wall surface, the reflected image is
When the two reference lines of the eyepiece reticle 52 are displaced to the left or right and the index of the light source reticle 51 is displaced in the Y direction parallel to the wall surface, the reflected image is relative to the two reference lines of the eyepiece reticle 52. Cause a tilt. By moving and adjusting the object 2 to be measured in the X and Y directions by the feeding device of the mounting stage 3, the wall surface of the small diameter hole 1 to be measured is aligned with the optical axis, and the position of the wall surface is detected. At this time, the position of one wall surface of the inner diameter is measured by the linear encoder 11. Such detection of the position of the wall surface is performed by visually observing the reflected image or automatically by an image processing device or the like.

However, in this method, the light emitting system and the light receiving system are
A black reticle that serves as an index or a reference line is used, and when detecting the position of the wall surface from the reflected image, the light is incident on the entire field of view or screen, so the scattered light on the wall surface of the small diameter hole 1 There is a problem that the contrast between the reticle index or the marked line and the background is not sufficient due to the multiple reflection light or the like, and the measurement error increases.

When measuring a long hole with a small diameter, the measurement error becomes large because the observation state of the reticle is not stable. Therefore, it is necessary to greatly change the magnification of the projection lens, the light receiving numerical aperture, and the light amount of the light source depending on the measurement target.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a hole shape measuring method and a measuring apparatus capable of non-contact and highly accurately measuring a small diameter hole shape. That is the purpose.

[0010]

According to a first aspect of the present invention, in the hole shape measuring method, the slit light is projected onto the wall surface of the hole through a projection system for projecting the slit light onto the measured position. , The reflected light on the wall surface is imaged at the light receiving position by the light receiving system, the optical axis of the slit light is relatively moved with the hole, and the tip of the arc of the slit light at the light receiving position is aligned with the optical axis. When they coincide with each other, the position of the hole is measured, and the inner diameter of the hole is measured by performing the measurement on both ends of the diameter of the hole.

According to the invention of claim 2, in the hole shape measuring method, the hole and the optical axis are relatively rotated, and the hole shape measuring method of claim 1 is performed for each rotation angle. The cross-sectional shape of the hole is measured by.

According to a third aspect of the present invention, in the hole shape measuring method, the hole and the optical axis are relatively moved in the axial direction of the hole, and the hole shape measuring method according to the first or second aspect. Is performed for each moving position to measure the hole bending, and thereby the hole bending is measured.

According to a fourth aspect of the present invention, in the hole shape measuring apparatus, a light projecting system having a focal point at a position to be measured and projecting slit light onto the wall surface of the hole, and an image pickup device facing the light projecting system. A light receiving system for receiving reflected light on the wall surface and forming an image of the slit light on the image pickup device; an optical system including the light projecting system and the light receiving system; and means for relatively moving the hole. A position measuring means for measuring a relative position between the optical system and the hole, and means for determining an inner diameter of a cross section of the hole based on measurement values at both ends of the diameter of the hole. is there.

According to a fifth aspect of the present invention, the hole shape measuring apparatus according to the fourth aspect is characterized in that it has means for relatively rotating the hole and the optical system.

According to a sixth aspect of the invention, in the hole shape measuring apparatus according to the fourth or fifth aspect, there is provided means for relatively moving the hole and the optical system in the axial direction of the hole. It is a feature.

[0016]

According to the first aspect of the present invention, the slit light is projected on the wall surface of the hole through the light projecting system which projects the slit light onto the measured position, and the reflected light on the wall surface is imaged on the light receiving position by the light receiving system. Let
When the optical axis of the slit light and the hole are moved relative to each other, and the tip of the slit light arc at the light receiving position coincides with the optical axis, the position of the hole is measured, and this measurement is performed for both ends of the diameter of the hole. Since the inner diameter of the hole is measured by performing it, even if the hole has a small diameter or a complicated structure where the probe cannot be inserted,
It is possible to measure the inner diameter without contact and with high accuracy. In addition, since the reflected image with a small amount of scattered light or multiple reflected light and a good contrast can be obtained, the observation state is stable,
The measurement error becomes small.

According to the second aspect of the present invention, the hole and the optical axis are rotated relative to each other, and the hole shape measuring method according to the first aspect is performed for each rotation angle, whereby the sectional shape of the hole is determined. Since the measurement is performed, the hole shape in an arbitrary cross section can be measured.

According to the invention described in claim 3, the hole and the optical axis are relatively moved in the axial direction of the hole, and the hole shape measuring method according to claim 1 or 2 is performed for each moving position. Since the hole bending is measured by the method, the change in the hole shape in the axial direction of the hole can be measured.

According to the fourth aspect of the present invention, a light projecting system which has a focal point at the position to be measured and projects the slit light onto the wall surface of the hole, and a reflection surface on the wall surface which includes the image pickup element and faces the light projecting system. A light-receiving system that receives light and forms slit light on the image sensor,
An optical system consisting of a light-projecting system and a light-receiving system and means for relatively moving the hole, and position measuring means for measuring the relative position of the optical system and the hole are provided, and the hole is based on the measured values at both ends of the diameter of the hole. Since it has a means for determining the inner diameter of the cross-section, it is possible to measure the inner diameter in a non-contact and highly accurate manner even for a hole having a small diameter in which a probe cannot be inserted or a hole having a complicated structure. In addition, a scattered image, multiple reflected light, and the like can be obtained, and a reflected image with a good contrast can be obtained, so that the observation state is stable and the measurement error is reduced.

According to the fifth aspect of the present invention, since the means for rotating the hole and the optical system relative to each other is provided, it is possible to measure the hole shape in a specific cross section.

According to the invention described in claim 6, since there is provided means for relatively moving at least one of the hole and the slit light source in the axial direction of the hole, the hole shape in the axial direction of the hole is Changes can be measured.

[0022]

1 is a plan view illustrating an embodiment of the present invention. In the figure, the same parts as those in FIG. 6 is a filter and 7 is a slit. The light emitted from the light source 4 is filtered along the optical axis 5 by the filter 6,
An image of the slit 7 is formed on the wall surface of the small diameter hole 1 through the slit 7 and the projection objective lens 8. The measured position is this image forming position, which is the focus position of the projection objective lens 8.
The linear slit 7 is opened in the Y-axis direction perpendicular to the paper surface in this figure, and the width direction of the slit 7 is sufficiently smaller than the longitudinal direction of the slit 7. The DUT 2 is held on the stage 3 using an attachment (not shown).
The mounting stage 3 is adjusted so that the axial direction of the small diameter hole 1 is the same as the left and right Z-axis directions as the optical axis 5. The fixing of the object to be measured 2 to the attachment and the fixing of the attachment to the mounting stage 3 both use position pins (not shown) to ensure position reproducibility.

On the light receiving side, the slit light imaged and reflected on the wall surface of the small diameter hole 1 is reflected by the light receiving objective lens 9 into an arc-shaped image on a two-dimensional image pickup device such as a CCD sensor (not shown) in the camera 10. Is imaged as. The slit light is observed on the monitor screen of the captured image, and the position of the stage 3 is adjusted so that the image forming position of the slit light and the surface to be measured on the wall surface of the small diameter hole 1 coincide with each other.

As the light source 4, for example, a halogen light source is used. The filter 6 is for converting the polychromatic light of the halogen lamp into monochromatic light to improve the measurement accuracy. At that time, it is preferable to use a green filter because the sensitivity of the CCD sensor is good. The light source may be a laser beam having a beam diameter increased through an optical system, and in this case, the filter 6 is not particularly required. The two-dimensional image pickup device is not limited to the CCD sensor and may be an image pickup tube.
The camera 10 may be replaced with a CCD sensor as a separate component. At that time, the optical system of the light receiving system is appropriately changed.

FIG. 2 is a front view illustrating a stage system according to an embodiment of the present invention. In the figure, the same parts as those in FIG. 6 and FIG. 21 is a base, 22 is an X stage, 23 is a Y stage, 24 is a Z stage, 25 is an optical system supporting unit, 26 is a light projecting system, 27 is a light receiving system, 28 is a θ stage supporting unit, 29 is a θ stage, Three
Reference numeral 0 is a η stage support portion, 31 is a stage, and 32 is a φ stage. An automatic stage including an X stage 22, a Y stage 23, and a Z stage 24 is mounted on the base 21 in this order, and is automatically moved in each of the X, Y, and Z directions by a drive device and a drive control device (not shown). Enabled A linear scale (not shown) is provided on the base 21, and a mover of this linear scale is attached to the X stage 22 and moves in conjunction with the X stage 22. Z
An optical system support 25 is attached on the stage 24, and an optical system including a light projecting system 26 and a light receiving system 27 is attached on the optical system support 25. Projection system 2
Reference numeral 6 denotes the light source 4, the filter 6, the projection objective lens 8 and the like shown in FIG. 1, but the light source 4 and the like are provided at other positions, and the light from the light source 4 is provided by a fiber bundle or the like. It may be guided to the light projecting system 26.

The base 21 also includes the θ stage support 2
8 is provided upright, and a θ stage 29 is provided on the θ stage support portion 28. The θ stage 29 is a stage that rotates around the Z axis, and is designed so that the center of rotation coincides with the optical axis 5. The θ stage 29 is also automatically rotatable about the Z axis by a drive device and a drive control device (not shown). The θ stage 29 has a small hole 1
The opening is sufficiently larger than that of the. Alternatively,
Instead of providing the opening, the θ stage 29 itself may be transparent. An η stage support portion 30 is attached to the θ stage 29, and an η stage support portion 30 is attached to the η stage support portion 30.
The stage 31 is attached. This η stage 31
It is a manual rotation stage. A φ stage 32 is attached to the η stage 31. The φ stage 32 is a manual goniometer stage. The DUT 2 is placed on the φ stage 32. The DUT 2 is held on the φ stage 32 by using an attachment (not shown) as needed. As described above, since the configuration of the stage system is complicated, in FIG.
Shows a simplified stage system.

In FIG. 2, the optical system including the light projecting system 26 and the light receiving system 27 is moved by the X stage 22 in the X axis direction perpendicular to the paper surface, and by the Y stage 23 in the upper and lower Y axis directions, Z The stage 24 moves to the left and right, that is, in the Z-axis direction in the depth direction of the small diameter hole 1. DUT 2 is
The φ stage 32 rotates about the X axis perpendicular to the paper surface, and the η stage 31 rotates about the upper and lower Y axes.
The θ stage 29 rotates about the Z axis in the depth direction of the small diameter hole 1.

In measuring the shape of the small diameter hole 1 described later,
By appropriately moving and adjusting each stage, positioning is performed so that the optical axis 5 penetrates the cross section at an arbitrary depth Z of the small diameter hole 1 which is the measured position. This arbitrary depth Z
Is the focus position of the projection objective lens 8 in the projection system 26. Then, the center position of this cross section is measured as the reference position. By moving the optical system back and forth in the X-axis direction by the X-stage, the positions of both wall surfaces facing each other in the X-axis direction around the reference position are measured, and from this measurement result, the specific depth of the small diameter hole 1 is determined. The length of the inner diameter of the cross section at Z is obtained. Next, the measured object 2 is centered around the reference position.
Is rotated by the θ stage 29, and the length of the diameter is obtained for each rotation angle.
The shape of the cross section and the hole eccentricity can be measured. Further, by moving the optical system in the Z-axis direction by the Z stage, it is possible to measure the change in the shape of the cross section of the small diameter hole 1 in the depth direction, that is, the bending of the hole. It should be noted that the method of determining the reference position, the measurement order, and the like can be arbitrarily determined, and the above description is merely an example.

Since the relative position between the optical axis 5 of the optical system and the small diameter hole 1 of the DUT 2 is measured by a linear scale, the optical system consisting of the light projecting system 26 and the light receiving system 27 is moved. Instead, the small diameter hole 1 of the DUT 2 may be moved, or both may be moved together. As for the rotation, the optical axis 5 is rotated around the center of the small diameter hole 1,
That is, the optical system including the light projecting system 26 and the light receiving system 27 may be rotated so that the slit light rotates around the center of the small diameter hole 1, or the small diameter hole 1 of the DUT 2 and the light projecting system may be rotated. Two
6, the optical system including the light receiving system 27 may be rotated together. Although the stage system shown in FIG. 2 has the Z-axis arranged horizontally, the Z-axis is arranged vertically so that the axial direction of the small-diameter hole 1 becomes vertical, and the stage system is measured. Good.

3A and 3B are explanatory views for explaining the first position of the object to be measured and the monitor screen. FIG. 3A is a plan view and FIG. 3B is a monitor screen. In the figure, the same parts as those in FIG. 6 and FIG. 41 is an image forming position, 42 is a reflection image of slit light, and 43 is a marked line. In FIG. 3 (A), the linear slit 7 is opened in the Y-axis direction perpendicular to the paper surface, and the slit light forms a minute image at the image forming position 41. In FIG. 3B, a marked line 43 is a vertical line provided at the center of the monitor screen. The reference line 43 is an image processing device (not shown) for inputting the output of the two-dimensional image pickup device to display an image on the monitor screen, and the like. However, it may be printed in advance on the display screen of the monitor device. The two-dimensional image pickup device is positioned so that the optical axis 5 is located at the center of the monitor screen.

At the first position of the DUT 2 shown in FIG. 3A, the optical axis 5 is located at a position slightly deviated from the center of the small diameter hole 1 in the negative direction of the X axis, that is, in the upward direction. . The slit light forms a minute image at the image forming position 41,
Part of the slit light is reflected by the wall surface of the small diameter hole 1. Therefore, both the direct light and the reflected light are reflected by the camera 10.
An image is formed on the two-dimensional image sensor inside. As shown in FIG. 3B, the slit light image 4 is displayed on the monitor screen.
No. 2 is observed as an arc shape, and the tip of this arc moves to the left from the marked line 43 and is displaced toward the adjacent wall surface.

In the illustrated monitor screen, the left side in the figure corresponds to the upward direction in FIG. 3 (A). However, depending on the configuration of the light receiving system and the scanning direction when outputting the image signal to the monitor screen, the left and right are displayed in reverse.

At the start of the measurement, the object 2 to be measured is shown in FIG.
In the case of the first position shown in Fig. 2, the monitor screen is observed, and the DUT 2 is moved in the X direction until the slit light image 42 becomes a straight line. Four
Adjust to the second position shown in (A).

FIG. 4 is an explanatory view for explaining the second position of the object to be measured and the monitor screen. FIG. 4A is a plan view and FIG.
(B) is a monitor screen. In the figure, the same parts as those in FIG. 6, FIG. 1 and FIG. At the first position of the DUT 2, the optical axis 5 is located at the center of the small diameter hole 1. In this case, the slit light forms a minute image at the image forming position 41, but is formed on the two-dimensional image pickup device in the camera 10 without being reflected by the wall surface of the small diameter hole 1. Therefore, on the monitor screen shown in FIG. 4A, the slit light image 42 is observed as a linear one. Since the two-dimensional image pickup device is positioned so that the optical axis 5 is located at the center of the monitor screen, the slit light image 42 is also located at the center of the monitor screen.

The wall surface is Y which is perpendicular to the paper surface in FIG.
When the image is displaced in the axial direction, the image 42 of the slit light is observed vertically displaced on the monitor screen shown in FIG. In this case, the optical axis 5 can be aligned with the center of the cross section of the measurement position of the small diameter hole 1 by moving the mounting stage 3 and adjusting the position of the measurement target 2 in the Y-axis direction. . From observation of the monitor screen, if the optical axis 5 and the axis of the small diameter hole 1 are misaligned around the X axis, adjust the φ stage, and if they are misaligned around the Y axis, adjust the η stage. The axis 5 and the central axis of the small diameter hole 1 can be made parallel.

It is adjusted so that the slit light image 42 becomes linear and is located at the center of the monitor screen. At this time, since the optical axis 5 coincides with the center of the small diameter hole 1 and the optical axis 5 is located at the center on the monitor screen, the center of the small diameter hole 1 is also located substantially at the center of the monitor screen. The center position of the small diameter hole 1 is set as a reference position. At this time, using the linear encoder 11, the position of the mounting stage 3, that is, the X of the DUT 2 is measured.
Record the axial position.

If the slit light image 42 is linearly displaced from the marked line to the left or right, it means that the position of the optical axis 5 is displaced from the center of the monitor screen.
In this case, the position of the slit light image 42 on the screen may be recorded as a reference point on the screen.

The object to be measured 2 is directed upward in FIG.
That is, it is shifted in the negative direction of the X axis. At this time, the DUT 2 moves from the center position of the small diameter hole 1 in the diameter direction of the small diameter hole. A part of the slit light starts to be reflected on the wall surface of the small diameter hole 1. Therefore, on the monitor screen shown in FIG. 4 (B), the slit light image 42, which is linear, begins to bend gradually, and the tip of the bend is on the wall surface closer to the center of the monitor screen. 3B starts to deviate gradually, and the same state as in FIG. 3B described above is observed.

When the wall surface of the small diameter hole 1 further moves toward the image forming position 42 of the slit light, the degree of bending increases, but the wall surface of the small diameter hole 1 approaches the marked line 43.
On the contrary, the bent tip approaches the marked line 43 on the monitor screen.

5A and 5B are explanatory views for explaining the third position of the object to be measured and the monitor screen. FIG. 5A is a plan view and FIG. 5B is a monitor screen. In the figure, the same parts as those in FIG. 6, FIG. 1 and FIG. When the optical axis 5 of the slit light and the wall surface of the small diameter hole 1 coincide with each other, the slit light image forming position 41 is located on the wall surface of the small diameter hole 1, and only the slit light reflected by the wall surface is reflected by the camera 10.
To reach the two-dimensional image sensor inside. In the slit light image 42 shown in FIG. 5 (A), the tip of the bend coincides with the position of the optical axis 5, and the tangent line of the arc coincides with the marked line. At this time, the optical axis 5 and the wall surface of the small diameter hole 1 coincide with each other, and the optical axis 5 is located at the center on the monitor screen. Therefore, the wall surface of the small diameter hole 1 is also located substantially at the center of the monitor screen.

At this time, the linear encoder 11 is used again to move the position of the mounting stage 3, that is, the X-axis of the DUT 2.
Record the axial position. By taking the difference from the position in the X-axis direction at the second position of the DUT 2 shown in FIG. 4, that is, the position at the reference position in the X-axis direction, the small-diameter hole 1 is moved from the reference position. The amount of movement to the wall surface, that is, the distance from the reference position to the wall surface of the small diameter hole 1 is obtained, and this is recorded. In addition, when the tangent line of the arc of the slit light image 42 is inclined with respect to the marked line, it means that the wall surface of the small diameter hole 1 is inclined with respect to the diameter of the small diameter hole 1. In this case, the tilt is also recorded, or the mounting stage is readjusted and the reference position is reset so that the tangent line of the arc of the slit light image 42 does not tilt with respect to the reference line. Start over.

Similarly, the object to be measured is moved in the opposite direction on the X-axis from the reference position shown in FIG. 4, and while observing the monitor screen, the other wall surface of the small diameter hole 1 and the slit are measured. The optical axis 5 of the light should be aligned. Also at this time, the position of the DUT 2 in the X-axis direction is recorded using the linear encoder 11. By taking the difference from the position in the X-axis direction at the reference position shown in FIG. 4, the amount of movement from the reference position to the other wall surface of the small diameter hole 1, that is, the other side of the small diameter hole 1 from the reference position. The distance to the wall of is determined and recorded.

By adding the movement amount from the reference position to each wall surface of the small diameter hole 1, that is, by adding the distance from the reference position to each wall surface of the small diameter hole 1, the small diameter hole 1 of the object to be measured 2 is added. The inner diameter of can be calculated. The recording and addition / subtraction of the measurement value of the linear encoder can be performed by an information processing device which inputs the output of the linear encoder 11. Although the movement amount from the reference position is recorded in the above description, the movement amount to the other wall face, that is, the length may be recorded with one wall face as a reference. In addition, at the reference position or the reference wall surface, the linear encoder 11 is reset, and the amount of movement to the wall surface,
That is, the distance may be directly read.

The object to be measured is rotated by the rotation angle θ around the Z axis coinciding with the optical axis 5 from the state of the reference position shown in FIG. 4, for example, by the θ stage shown in FIG.
Then, by performing the above-mentioned inner diameter measurement at the position of each rotation angle θ, the hole shape of the cross section at an arbitrary depth of the small diameter hole 1 can be measured. Further, similarly, by similarly measuring the hole shapes for the cross sections of the small diameter hole 1 at different depths, the bending of the small diameter hole 1 in the depth direction can be obtained.

At the time of the above measurement, the movement of the object 2 is automatically measured by inputting data obtained by image-processing the picked-up image to the drive control device and controlling the drive of each stage. be able to. By such automation, it is possible to reduce the visual measurement error and reduce the burden on the measurement operator. In this case, the picked-up image obtained by the two-dimensional image pickup device in the camera 10 is input to the image processing apparatus, and then the image pickup apparatus shown in FIG.
The state of the captured image shown in FIG. FIG.
In (B), the position of the optical axis 5 on the two-dimensional image sensor is detected and stored. In FIG. 3 (B), FIG. 5 (B), etc.,
The tip position of the arc bend of the slit image 42 is detected and stored. Then, the distance between the position of the optical axis 5 and the position of the tip of the arc bend is determined, and the drive of each stage is controlled so that this distance becomes zero.

As one specific example of the determination of the distance between the position of the optical axis 5 and the position of the tip of the arc bend, a picked-up image corresponding to the monitor screen is displayed in pixel units on a two-dimensional image memory in the image processing apparatus. Of pixels having an amplitude level corresponding to the slit image 42 shown in FIG. 4B, the position of the optical axis 5, that is, the horizontal axis coordinate value of the pixel at the center of the slit image 42. To detect. Further, the horizontal axis coordinate value of the leftmost pixel in the horizontal axis direction is detected from the pixels having the amplitude level corresponding to the slit image 41 shown in FIGS. 3B and 5B. To do. Then, the difference between the two horizontal axis coordinate values is calculated.

To detect the state where the arc of the slit image 41 in FIGS. 4B and 3B is vertically symmetrical with respect to the central horizontal axis, the vertical direction of the pixel where the upper end of the arc is located is detected. The axis coordinate value and the vertical axis coordinate value of the pixel where the lower end is located are compared with the same horizontal axis coordinate value, and the middle of the two vertical axis coordinate values is the vertical axis position of the optical axis 5, that is, FIG. , The vertical axis coordinate value of the pixel at the center of the slit image 41 in FIG.

Not only the position output of the linear scale 11 in the X-axis direction but also the automatic Y stage 23 and the automatic Z stage 2 are provided to the image processing apparatus or the information processing apparatus which is linked with the image processing apparatus.
4, a small-diameter hole 1 that receives position outputs in the Y-axis direction and Z-axis direction and angle outputs of angles θ, η, and φ from a measuring device (not shown) attached to the automatic θ stage, η stage 31, and φ stage. It is also possible to calculate the diameter and the eccentricity, and store or display the calculation result. In the image processing device, image processing is performed on the image memory such as emphasizing or thinning the image 42 of the slit light so as to stand out. Also, if necessary, a graphic insertion process is performed so that a virtual graphic such as a circle indicating the position of the marked line 43 or the small diameter hole 1 is displayed on the monitor screen, or the gradation of light and dark is pseudo-colored. be able to.

The above description is based on the assumption that the cross-sectional shape does not change in the depth direction and the wall surface has a linear cross section. However, it can be measured even when the cross-sectional shape changes in the depth direction like an actual die hole. However,
In this case, since the cross section of the wall surface is inclined with respect to the optical axis 5 along the Z-axis direction, the incident light on the optical axis 5 is also reflected by the wall surface and bent, which causes a slight error in measurement. Will occur. Therefore, for example, after adjusting the rotation angle φ around the X axis and the rotation angle η around the Y axis so that the light amount of the image of the slit becomes large, the incident light on the optical axis 5 is contacted with the wall surface. The error is eliminated by measuring the position at the predetermined depth of the measurement position.

In the embodiment described above, the slit 7
The shape of is a linear slit, but is not limited to this.
If you adopt the same cross-shaped slit as the index of the prior art,
On the monitor screen shown in FIG. 4B, etc., the alignment in the vertical axis direction becomes easy, and the hole diameters in the directions orthogonal to each other can be measured without rotating the mounting stage 3. . Also, if you adopt a spot-shaped slit,
An image of only the central portion of the optical axis 5 is formed, and the distance between the position of the optical axis 5 and the tip position of the arc bending can be easily identified on the monitor screen shown in FIG. . Alternatively, the light source 4 itself may generate the slit light having the above-described shape. In this case, the slit 7 as a single component is unnecessary, but it can be said that the slit 7 is substantially provided.

In the above-mentioned embodiment, the two-dimensional image pickup device is arranged at the slit light detection position, but the operator may directly observe the slit image as in the prior art. When taking such a measurement method,
No image processing device or the like is required.

[0052]

As is apparent from the above description, according to the present invention, by making the incident light into slit light, the influence of scattered light, multiple reflection, etc. is small, and the formed image and background are There is an effect that the contrast is improved and it becomes possible to measure the shape of the small hole diameter with high accuracy. Therefore,
Furthermore, by combining lenses having different characteristics such as magnification and light receiving numerical aperture and slits having different widths, and adjusting the light amount of the light source, it is possible to perform measurements corresponding to various shapes of DUT under different conditions. When the present invention is used, for example, to measure the inner shape of a die hole used for resin coating of an optical fiber, it is possible to judge whether the die is good or bad without actually coating the resin on the optical fiber with a die. Therefore, the resin coating failure of the optical fiber can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view illustrating an embodiment of the present invention.

FIG. 2 is a front view illustrating a stage system according to an embodiment of the present invention.

3A and 3B are explanatory views for explaining a first position of the object to be measured and a monitor screen. FIG. 3A is a plan view and FIG.
It is a monitor screen.

4A and 4B are explanatory views for explaining a second position of an object to be measured and a monitor screen, FIG. 4A is a plan view, and FIG. 4B is a monitor screen.

5A and 5B are explanatory views illustrating a third position of the object to be measured and a monitor screen. FIG. 5A is a plan view and FIG.
It is a monitor screen.

FIG. 6 is an explanatory diagram illustrating a conventional inner diameter measuring device having an extremely small diameter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Small-diameter hole, 2 ... Object to be measured, 3 ... Mounting stage, 4 ... Light source, 5 ... Optical axis, 6 ... Filter, 7 ... Slit, 8 ... Projection objective lens, 9 ... Receiving objective lens, 10 ... Camera , 11
... Linear encoder, 41 ... Image forming position, 42 ... Reflected image of slit light, 43 ... Mark line, 51 ... Light source reticle, 52 ...
Eyepiece reticle.

Claims (6)

[Claims] 1. The optical axis of the slit light is projected onto the wall surface of the hole through a light projecting system for projecting the slit light onto the measured position, and the reflected light from the wall surface is imaged on the light receiving position by the light receiving system. When the tip of the slit light arc at the light receiving position coincides with the optical axis, the position of the hole is measured, and the measurement is performed with respect to both ends of the diameter of the hole. A hole shape measuring method, characterized in that the inner diameter of the hole is measured by carrying out. 2. The relative rotation of the hole and the optical axis,
A hole shape measuring method comprising: measuring the sectional shape of the hole by performing the hole shape measuring method according to claim 1 for each rotation angle. 3. The hole bend is measured by moving the hole and the optical axis relative to each other in the axial direction of the hole and performing the hole shape measuring method according to claim 1 or 2 for each moving position. A hole shape measuring method characterized by the above. 4. A light projecting system which has a focus at a position to be measured and projects slit light onto a wall surface of a hole, and an image sensor which is opposed to the light projecting system and which receives reflected light on the wall surface. A light receiving system for forming an image of the slit light on the above, an optical system including the light projecting system and the light receiving system, a means for relatively moving the hole, and a position for measuring the relative position of the optical system and the hole. A hole shape measuring device comprising: a measuring means; and a means for obtaining an inner diameter of a cross section of the hole based on measurement values at both ends of the diameter of the hole. 5. The hole shape measuring device according to claim 4, further comprising means for relatively rotating the hole and the optical system. 6. The hole shape measuring device according to claim 4, further comprising means for relatively moving the hole and the optical system in an axial direction of the hole.