JP2010014656A - Noncontact side-surface shape measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noncontact side-surface shape measuring apparatus for measuring the side-surface shape of a measure workpiece. <P>SOLUTION: A laser beam L radiated downward is reflected on a prism 12 in the X-axis direction, so that the inner surface shape of the center hole 1a of a cylindrical member 1 can also be measured. Especially, the apparatus includes a structure where the prism 12 positioned at the lower end, an objective lens means 21, and a first image forming lens means 20 are fixed, so that a head 10 can be miniaturized. Auto-focus can be performed by a collimator lens means 18 moving in the Z-axis, so that a probe 9 can be formed to be long while having a narrow diameter. Therefore, the head 10 is deeply inserted into the center hole 1a of the cylindrical member 1, and the shape of its inner surface can be measured. By repeating circumferential measurement while changing the position of the Z-axis direction, the three-dimensional shape of the inner surface can be measured. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a non-contact side surface shape measuring apparatus.

  It is known that a laser probe type non-contact shape measuring apparatus using laser autofocus can measure the shape and roughness of precision parts over a wide range with nano-level resolution. That is, as the three-dimensional orthogonal coordinate axis XYZ, the measurement workpiece is scanned in the X and Y directions while autofocusing with a laser beam is applied to the upper surface of the measurement workpiece to be measured in the Z-axis direction, which is the vertical direction. It is a structure which acquires the measurement data regarding the surface shape of a measurement workpiece | work from the movement amount in the Z-axis direction of this objective lens (for example, refer patent document 1).

That is, the laser light as the probe light is introduced at a position parallel to the optical axis of the objective lens and shifted from the optical axis, and intersects the optical axis at the focal plane of the objective lens. Since the crossing position is fixed with respect to the objective lens, the irradiation position in the X-axis or Y-axis direction on the surface of the measurement workpiece moves when the objective lens moves in the Z-axis direction. The position of the laser beam reflected at one point on the surface of the measurement work is detected by the optical position detector via the objective lens. Since the positional deviation between the surface of the workpiece to be measured and the focal plane of the objective lens is measured from the detection position of the reflected light, autofocus is realized by feedback control of this. As a result, the shape of the workpiece surface can be measured from the position of the objective lens in the Z-axis direction.
JP 2005-201656 A

  However, in such a related technique, since the laser beam as the laser probe that has passed through the objective lens is applied to the upper surface of the measurement workpiece in the Z-axis direction, only the upper surface shape of the measurement workpiece can be measured. In addition, the side shape of the measurement workpiece could not be measured. In particular, it was not possible to measure the inner surface shape of a deep portion in the hole of the measurement workpiece having a cylindrical shape.

  The present invention has been made paying attention to such a conventional technique, and provides a non-contact side surface shape measuring apparatus capable of measuring a side surface shape of a measurement workpiece.

  According to the first aspect of the present invention, the three-dimensional orthogonal coordinate axis XYZ is a laser beam irradiation means for irradiating a laser beam downward in parallel with the vertical Z axis, and a downward laser beam fixed below the Z axis and the X axis Reflecting means for reflecting the laser light reflected on the side surface of the measurement workpiece located on the X axis and reflecting upward, and transmitting the laser light fixed on the X axis and reflected by the reflecting means. An objective lens unit that transmits the laser beam reflected on the side of the measurement work and transmits the laser beam to the reflecting unit, and a laser beam that is fixed on the Z axis above the reflecting unit and reflected upward from the reflecting unit. First imaging lens means for imaging light at a first imaging point on the Z axis; and laser light that is movable in the Z axis direction and that has passed through the first imaging point, and passes the optical path along the Z axis. Collimator parallel Means, a second imaging lens means for forming an image of the laser light transmitted through the collimator lens means at a second imaging point of the optical axis, and an optical position detection for receiving the laser light transmitted through the second imaging lens means And a focusing means for moving the collimator lens means in the Z-axis direction so as to make the focal point of the laser beam coincide with the side surface of the measurement workpiece based on the position signal from the optical position detection means.

  The invention according to claim 2 is characterized in that relay lens means for forming an intermediate image forming point is fixed between the first image forming lens means and the collimator lens means.

  According to a third aspect of the present invention, there is provided a θ-direction moving means for rotating the measurement workpiece relative to the θ direction in the horizontal direction around a predetermined rotation center.

  According to a fourth aspect of the present invention, there is provided an X-axis direction moving means for relatively translating the measurement workpiece in the X-axis direction.

  According to a fifth aspect of the present invention, there is provided a Y-axis direction moving means for relatively translating the measurement workpiece in the Y-axis direction.

  The invention described in claim 6 is characterized in that there is provided a Z-axis direction moving means for moving the entire workpiece relative to the Z-axis direction.

  According to a seventh aspect of the present invention, there is provided a light branching means for horizontally branching the laser beam on the Z-axis above the collimator lens means, and the second imaging lens means and the light position detecting means are parallel to the light branching means. The position is fixed.

  According to the first aspect of the present invention, the laser beam irradiated downward is reflected by the reflecting means in the X-axis direction, so that the side shape of the measurement workpiece can also be measured. In particular, the reflecting means, the objective lens means, and the first imaging lens means located at the lower end are fixed, so that they can be miniaturized and can be easily inserted into narrow grooves or small diameter holes. The inner surface shape of grooves and holes can be measured. Since auto-focusing is performed by the collimator lens means that moves in the Z axis, the length in the Z-axis direction of the portion below the collimator lens means can be enlarged, and the measurement of a deep part of the groove or hole is also possible. Further, the focal length of the first imaging lens unit in the Z-axis direction is made larger than that of the objective lens unit in the X-axis direction, and the displacement in the Z-axis direction is acquired larger than the displacement in the X-axis direction. It is possible to measure the displacement more than the positioning accuracy of the optical position detecting means.

  According to the second aspect of the present invention, by fixing the relay lens means between the first imaging lens means and the collimator lens means, the length in the Z-axis direction of the portion below the collimator lens means is further enlarged. can do.

  According to the third aspect of the invention, since the θ-direction moving means for rotating the measurement workpiece in the θ direction is provided, it is possible to measure the two-dimensional shape scanned in the θ direction on the side surface of the measurement workpiece. it can.

  According to the fourth aspect of the present invention, since the X-axis direction moving means for moving the measurement workpiece relatively in the X-axis direction is provided, the objective lens means is optimal for measurement with respect to the side surface of the measurement workpiece. Can be set to distance.

  According to the fifth aspect of the present invention, since the Y-axis direction moving means for relatively translating the measurement workpiece in the Y-axis direction is provided, the two-dimensional shape scanned in the Y-axis direction on the side surface of the measurement workpiece is obtained. Can be measured.

  According to the sixth aspect of the invention, since the Z-axis direction moving means for moving the measurement workpiece relatively in the Z-axis direction is provided, the two-dimensional shape scanned in the Z-axis direction on the side surface of the measurement workpiece is obtained. In addition to being able to measure, the three-dimensional shape of the side surface can be measured by combining with scanning in the θ-axis or Y-axis direction.

  According to the seventh aspect of the present invention, the light branching means for horizontally branching the laser beam is provided on the Z axis above the collimator lens means, and the second imaging lens means and the light position detecting means are provided with the light branching. Since it is fixed at a position horizontal to the means, it is possible to install other components such as a camera on the Z axis above the light branching means.

  1-7 is a figure which shows 1st Embodiment of this invention. First, the overall structure will be described with reference to FIG. In FIG. 1, XY is two directions orthogonal to each other on the horizontal plane, and Z is a vertical direction perpendicular to XY. θ is the direction of rotation.

  A measurement workpiece as a measurement target in the present embodiment is a cylindrical member 1 and has a circular center hole 1a at the center. The cylindrical member 1 is placed on a disk-shaped rotary stage (θ direction moving means) 2. The rotary stage 2 is assembled on an X-axis stage (X-axis direction moving means) 3 that is slidable in the X-axis direction. The X-axis stage 3 is assembled on a Y-axis stage (Y-axis direction moving means) 4 that is slidable in the Y-axis direction. The Y-axis stage 4 is placed on the base table 5. A support 6 is erected on the base 5, and a Z-axis stage (Z-axis moving means) 7 that is slidable in the Z-axis direction with respect to the support 6 is supported.

  A drive unit 8 is fixed to the Z-axis stage 7, and a cylindrical probe 9 is formed downward from the drive unit 8 (see FIG. 2). A head 10 is formed at the lower end of the probe 9. The probe 9 is thin and the head 10 has a small box shape. A window 11 is formed on the side surface of the head 10 in the X-axis direction.

  Next, the structure of the autofocus optical system will be described with reference to FIG. In FIG. 3 and its equivalent diagrams, the vertical optical axis is made coincident with the Z-axis, and the optical path in the Z-axis direction is shortened.

  Laser light L, which is a semiconductor laser as measurement light, is emitted from the laser light irradiation means 13. The laser beam irradiation means 13 includes a laser beam generator 14 that irradiates the laser beam L in the horizontal direction, and a beam splitter 15 that is fixed on the Z axis and reflects the laser beam L downward from a position parallel to the Z axis and offset. It consists of and. In the drawing, the optical path of the laser light L is indicated by a solid line and the reflected light is indicated by a dotted line.

  Above the beam splitter 15, second imaging lens means 16 is fixed on the Z axis, and above the second imaging lens means 16, optical position detection means 17 is installed on the Z axis. The optical position detection means 17 is a split photosensor, and the center portion 17S coincides with the image forming point of the second imaging lens means 16, and the spot centroid (optical centroid) of the laser light L coincides with the center portion 17S. By doing so, the output of each of the divided photosensors is balanced.

  A collimator lens unit 18 is provided below the beam splitter 15. The collimator lens means 18 can be moved in the Z-axis direction by a focus means 19 which is a servo mechanism. The focus unit 19 moves the collimator lens unit 18 based on the signal from the light position detection unit 17. All structures above the collimator lens means 18 are accommodated in the drive unit 8.

  The probe 9 which is long in the vertical direction is hollow, and a prism 12 as a reflection means is installed in a head 10 at the lower end thereof with a square reflection plane of 45 degrees facing the window 11 in the X-axis direction. . An X axis that matches the horizontal optical axis is formed from the prism 12.

  A first imaging lens means 20 is fixed above the prism 12. The first imaging lens means 20 forms a first imaging point P1 on the Z axis at an intermediate position of the probe 9.

  Objective lens means 21 is fixed on the window 11 side of the prism 12. The objective lens means 21 forms a focal point F on the X axis. In this embodiment, the focal length of the first imaging lens unit 20 on the Z axis is set to be sufficiently larger than the focal length of the objective lens unit 21 on the X axis.

  Next, the operation will be described.

  As shown in FIG. 1, the cylindrical member 1 is placed on a rotary stage 2 in order to measure the shape of the inner surface of the center hole 1a along the circumferential direction. Next, the Z-axis stage 7 is lowered, and the head 10 of the probe 9 is inserted into the center hole 1 a of the cylindrical member 1. After inserting the head 10, the X-axis stage 3 is slid to set the objective lens means 21 at an optimum distance for measurement with respect to the inner surface of the center hole 1a.

  Next, the basic optical path will be described with reference to FIG. After the setting of the head 10 with respect to the cylindrical member 1 is completed, the laser light L is irradiated horizontally from the laser light generator 14. Part of the horizontally irradiated laser beam L is reflected downward by the beam splitter 15. The optical path of the laser beam L irradiated downward passes through the collimator lens unit 18 in a state parallel to and offset from the Z axis, passes through the probe 9 and reaches the first imaging lens unit 20.

  The laser light L transmitted through the first imaging lens means 20 and parallel to the Z axis is reflected by the prism 12 in the horizontal direction, passes through the objective lens means 21, and passes through the window 11 of the head 10 through the center hole 1 a. Irradiated to the inner surface of.

  The laser beam L reflected by the inner surface of the center hole 1a is transmitted again through the objective lens means 21, reflected upward by the prism 12, transmitted through the first imaging lens means 20, and is reflected on the Z axis. Connect one imaging point P1. The first image point P1 is captured by the collimator lens means 18.

  The laser light L parallel to the Z axis by the collimator lens means 18 passes through the beam splitter 15, passes through the second imaging lens means 16, and passes through the second imaging point at the central portion 17S of the optical position detection means 17. P2 is formed. In a state where the second image formation point P2 of the laser light L coincides with the central portion 17S of the light position detection means 17, the focus means 19 is not driven and the position of the collimator lens means 18 remains unchanged.

  Since the laser light L is transmitted through the non-center portion of the objective lens means 21 and the collimator lens means 18 etc., for example, the inner surface of the center hole 1a is displaced in the − direction with respect to the head 10 from the state of FIG. 4) or displacement in the + direction (FIG. 6), the second imaging point P2 of the laser light L on the optical position detection means 17 is also displaced from the central portion 17S (FIGS. 4 and 6).

  For example, as shown in FIG. 4, when the inner surface of the center hole 1 a is displaced in the direction away from the head 10 by −d, the laser light L reflected by the inner surface of the center hole 1 a is the end of the objective lens means 21. The first image forming point P1 formed on the Z axis is displaced downward through the prism 12 and the first image forming lens means 20 while passing through the side and not parallel to the X axis and the Z axis. Then, the second imaging point P2 of the laser light L that has passed through the collimator lens means 18, the beam splitter 15, and the second imaging lens means 16 is displaced by -D from the central portion 17S in the optical position detection means 17.

  When the second imaging point P2 is shifted from the central portion 17S, the output from the shifted photosensor becomes larger, and the output balance between the two photosensors is lost. The servo-type focusing unit 19 moves the collimator lens unit 18 downward until a signal is output from the focusing unit 19 to the focusing unit 19 and the second imaging point P2 matches the central portion 17S. When the second image formation point P2 coincides with the central portion 17S, the image formation point of the laser light L transmitted through the objective lens 21 is also located on the X-axis axis before the focal length, and is in a focused state. The movement of the collimator lens means 18 is stopped. This is the autofocus operation.

  When the inner surface of the center hole 1a is displaced in the + direction on the contrary to the head 10, an autofocus operation opposite to the above is performed (FIGS. 6 and 7).

  In the autofocus operation as described above, the amount of movement of the collimator lens means 18 and the displacement d of the inner surface of the center hole 1a with respect to the head 10 are in a proportional relationship. Therefore, by detecting the amount of movement of the collimator lens means 18 The shape (unevenness) of the inner surface of the center hole 1a can be measured.

  In particular, in this embodiment, since the focal length of the first imaging lens means 20 in the Z-axis direction is set sufficiently larger than the objective lens means 21 in the X-axis direction, the displacement in the X-axis direction is set. With respect to d, the amount of displacement of the collimator lens means 18 in the Z-axis direction increases, and displacement measurement that is greater than the positioning accuracy of the optical position detection means 17 becomes possible.

  That is, since the cylindrical member 1 is mounted on the rotary stage 2, the two-dimensional shape in the circumferential direction of the inner surface of the center hole 1a is measured by rotating the cylindrical member 1 in the θ direction by the rotary stage 2. can do.

  Further, after the measurement of the two-dimensional shape in the circumferential direction of the inner surface of the center hole 1a is completed by the head 10 at a certain height position, the same shape measurement is repeated by changing the height position of the head 10. This also makes it possible to measure the three-dimensional shape related to the inner surface of the center hole 1a.

  According to this embodiment, since the prism 12, the objective lens means 21, and the first imaging lens means 20 positioned at the lower end are fixed, the size of the head 10 can be reduced. Further, since the autofocus is performed by the collimator lens means 18 that moves on the Z axis, the probe 9 can be formed long with a small diameter. Therefore, the head 10 can be inserted deeply into the central hole 1a of the cylindrical member 1 and the shape of the inner surface can be measured.

  FIG. 8 is a diagram showing a second embodiment of the present invention. This embodiment includes the same components as those in the first embodiment. Therefore, the same constituent elements are denoted by common reference numerals, and redundant description is omitted.

  In this embodiment, the relay lens means 22 that forms the intermediate image forming point P3 is fixed between the first imaging lens means 20 and the collimator lens means 18. By doing in this way, a probe can be lengthened further and it can measure to the inner surface (side surface) of a deeper part.

  FIG. 9 is a diagram showing a third embodiment of the present invention. This embodiment also includes the same components as those in the first embodiment. Therefore, the same constituent elements are denoted by common reference numerals, and redundant description is omitted.

  In this embodiment, the beam splitter 15 is used as an optical branching unit, and another beam splitter 23 is installed in the horizontal direction at the same height. The laser beam generator 14 was installed on the upper part of the beam splitter 23, and the two beam splitters 15 and 23 and the laser beam generator 14 constituted the laser beam irradiation means 24.

  A horizontal optical axis K is formed from the beam splitter 15, and the beam splitter 23, the second imaging lens unit 16, and the optical position detection unit 17 are installed on the horizontal optical axis K.

  An imaging lens 25 for photographing is installed on the beam splitter 15, and a camera (CCD imaging device) 26 is installed thereon.

  The laser beam L emitted from the laser beam generator 14 is reflected by the two beam splitters 15 and 23 and then passes through the collimator lens unit 18, the first imaging lens unit 20, the prism 12 and the objective lens unit 21. It hits the inner surface of the hole 1a. The reflected laser beam L returns in the opposite direction, and a part of the reflected laser beam L is reflected in the horizontal direction by the beam splitter 15 and then passes through the beam splitter 23 and the second imaging lens means 16 to detect the optical position. Light is received by the means 17 and autofocus control is performed.

  Since the camera 26 is installed on the Z axis above the beam splitter 15, an image of the inner surface of the center hole 1 a can be monitored by the camera 26.

  According to this embodiment, since the second imaging lens unit 16 and the optical position detection unit 17 are removed from the Z axis, it is possible to install another component (camera 26) on the Z axis.

  In each of the above embodiments, the example in which the inner surface of the center hole 1a is measured in the circumferential direction has been shown, but the outer surface of the cylindrical member 1 may be measured in the circumferential direction. In addition to the cylindrical member 1, the inner surface of the groove may be measured along the Y-axis direction or measured along the Z-axis direction. Although the prism 7 is taken as an example of the reflecting means, a mirror may be used.

The perspective view which shows the non-contact side surface shape measuring apparatus which concerns on 1st Embodiment of this invention. The perspective view which shows a probe and a head. The optical path figure which shows a non-contact side surface shape measuring apparatus. The optical path figure which shows the state which the inner surface displaced to the minus direction. The optical path diagram which shows the state which corrected the displacement to a minus direction by autofocus. The optical path figure which shows the state which the inner surface displaced to the plus direction. The optical path diagram which shows the state which corrected the displacement to the plus direction by autofocus. The optical path figure which shows the non-contact side surface shape measuring apparatus which concerns on 2nd Embodiment of this invention. The optical path figure which shows the non-contact side surface shape measuring apparatus which concerns on 3rd Embodiment of this invention.

Explanation of symbols

1 Cylindrical member (measurement workpiece)
1a Center hole 2 Rotating stage (θ direction moving means)
3 X-axis stage (X-axis direction moving means)
4 Y-axis stage (Y-axis direction moving means)
7 Z-axis stage (Z-axis direction moving means)
12 Prism (reflecting means)
13 Laser light irradiation means 16 Second imaging lens means 17 Optical position detection means (light branching means)
18 Collimator lens means 19 Focus means 20 First imaging lens means 21 Objective lens means 22 Relay lens means 23 Beam splitter L Laser light A Probe diameter B Probe length F Focus P1 First imaging point P2 Second imaging Point P3 Intermediate imaging point K Horizontal optical axis

Claims (7)

Laser light irradiation means for irradiating laser light downward in parallel with the vertical Z axis as a three-dimensional orthogonal coordinate axis XYZ;
Reflecting means fixed below the Z-axis and reflecting downward laser light in the X-axis direction and reflecting laser light reflected by the side surface of the measurement workpiece located on the X-axis upward;
Objective lens means that is fixed on the X axis and transmits the laser light reflected by the reflecting means to the focal point and transmits the laser light reflected from the side surface of the measurement workpiece to the reflecting means;
First imaging lens means for imaging a laser beam fixed on the Z axis above the reflecting means and reflected upward from the reflecting means at a first imaging point on the Z axis;
Collimator lens means that is movable in the Z-axis direction and transmits the laser light that has passed through the first imaging point and makes its optical path parallel to the Z-axis,
Second imaging lens means for imaging the laser beam transmitted through the collimator lens means at a second imaging point of the optical axis;
Optical position detection means for receiving laser light transmitted through the second imaging lens means;
A non-contact side shape comprising: a focus means for moving the collimator lens means in the Z-axis direction so that the focus of the laser beam is made to coincide with the side face of the measurement workpiece based on a position signal from the light position detection means measuring device.   2. The non-contact side surface shape measuring apparatus according to claim 1, wherein relay lens means for forming an intermediate image forming point is fixed between the first image forming lens means and the collimator lens means.   3. The non-contact side surface shape measuring apparatus according to claim 1, further comprising a θ-direction moving unit that relatively rotates the measurement workpiece in the θ direction in a horizontal direction around a predetermined rotation center.   The non-contact side surface shape measuring device according to any one of claims 1 to 3, further comprising an X-axis direction moving unit that relatively translates the measurement workpiece in the X-axis direction.   The non-contact side surface shape measuring apparatus according to claim 1, further comprising a Y-axis direction moving unit that relatively translates the measurement workpiece in the Y-axis direction.   The non-contact side surface shape measuring apparatus according to any one of claims 1 to 5, further comprising a Z-axis direction moving unit that moves the entire workpiece relative to the Z-axis direction.   A light branching means for horizontally branching the laser beam is provided on the Z-axis above the collimator lens means, and the second imaging lens means and the light position detecting means are fixed at a position horizontal to the light branching means. The non-contact side surface shape measuring apparatus according to any one of claims 1 to 6.

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