JP6567410B2 - Non-contact concave shape measuring device - Google Patents

Description

  The present invention relates to a non-contact concave shape measuring apparatus capable of measuring the bottom and side surfaces of concave portions such as narrow holes and grooves.

  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 with nano-level resolution. While applying autofocus with laser light to the surface of the workpiece being measured, the workpiece is scanned in the X and Y directions, and the surface shape of the workpiece is measured from the amount of movement of the objective lens of the autofocus optical system. It is a structure for acquiring data.

  Recently, in order to measure the inner surface by inserting into a narrow hole or groove, a relay lens is provided at the tip of the objective lens to extend the optical system, and the relay lens is moved instead of the objective lens. A technique for measuring the inner surface of the recess is also proposed (see, for example, Patent Document 1).

JP 2002-39724 A

  However, in such a related technique, the positional relationship between the objective lens and the relay lens changes relatively, so that the structure for accurately maintaining the optical relationship between the two is complicated. Further, if the relay lens is narrowed to be inserted into the narrow concave portion, it becomes difficult to maintain the optical positional relationship between the objective lens and the relay lens accurately, and it becomes difficult to maintain precise measurement accuracy.

  The present invention has been made by paying attention to such related technology, and an object of the present invention is to provide a non-contact concave shape measuring apparatus capable of maintaining high measurement accuracy even when an optical system is extended by a relay lens. It is said.

  According to the first technical aspect of the present invention, there is provided a non-contact concave shape measuring apparatus that measures the bottom surface of a concave portion of a measurement workpiece, and irradiates a laser beam parallel to an optical axis that matches the depth direction of the concave portion. A fixed optical unit having a laser beam irradiation unit and a light position detection unit that receives a returning laser beam parallel to the optical axis at the time of focusing through an imaging lens; an objective lens; and an objective lens A probe unit in which a lens barrel having a small diameter and provided with a plurality of relay lenses is integrated with a frame so that each lens tube is in a state of being projected along the optical axis, and the lens barrel of the probe unit A focus adjustment unit that moves the entire probe unit in the direction of the optical axis so that the focal point of the laser beam is made to coincide with the bottom surface of the recess by a position signal from the optical position detecting means in a state where is inserted in the recess Characterized by comprising a.

  According to a second technical aspect of the present invention, there is provided a non-contact concave shape measuring apparatus for measuring a side surface of a concave portion of a measurement workpiece, which irradiates a laser beam parallel to an optical axis that matches the depth direction of the concave portion. A fixed optical unit having a laser beam irradiation unit and a light position detection unit that receives a returning laser beam parallel to the optical axis at the time of focusing through an imaging lens; an objective lens; and an objective lens A probe unit in which a lens barrel having a small diameter and provided with a plurality of relay lenses is integrated with a frame so that each lens tube is in a state of being projected along the optical axis, and the lens barrel of the probe unit In the state in which the probe unit is inserted into the recess, the entire probe unit is moved in the optical axis direction so that the focal point of the laser beam reflected by the reflection unit by the position signal from the optical position detection unit matches the side surface of the recess. And adjustment unit, characterized in that and a separately installed reflecting means for bending the optical axis of the arranged probe unit into the recess in the perpendicular direction while being separated from the probe unit.

  According to a third technical aspect of the present invention, there is provided a non-contact concave shape measuring apparatus for measuring a side surface of a concave portion of a measurement work, wherein laser light parallel to a first optical axis perpendicular to the depth direction of the concave portion is obtained. A fixed optical unit comprising: a laser beam irradiating unit for irradiating; and a light position detecting unit for receiving a returning laser beam that is parallel to the first optical axis during focusing through an imaging lens; and a first optical axis Is provided with an optical axis reflecting means for bending the optical axis to a second optical axis that matches the depth direction of the recess, an objective lens, a plurality of relay lenses having a smaller diameter than the objective lens, and a second optical axis of the objective lens at the tip. A probe unit in which a lens barrel having tip reflecting means that bends in the direction of one optical axis is integrated with a frame so that the lens barrel is projected along the second optical axis; The lens barrel inserted into the recess And a focus adjustment unit that moves the entire probe unit in the first optical axis direction so that the focal point of the laser beam reflected by the tip reflecting means by the position signal from the light position detecting means matches the side surface of the recess. It is characterized by that.

  According to the first technical aspect of the present invention, since the objective lens and the relay lens are integrated by the frame and the positional relationship between them is fixed, even if the diameter of the lens barrel that houses the relay lens is reduced. The optical positional relationship between the objective lens and the relay lens can be accurately maintained. Accordingly, the bottom surface can be accurately measured even with a small-width recess.

  According to the second technical aspect of the present invention, since the reflecting means is separated from the probe unit, the structure of the probe unit is left as it is, and the side surface of the recess is irradiated with the laser light. The side can be measured. This technique is suitable for application to a recess of a penetrating structure.

  According to the third technical aspect of the present invention, since the tip of the relay lens has the tip reflecting means, it is not necessary to prepare a separate reflecting means for measuring the side face of the recess, and the lens barrel can be inserted. If it is a recessed part, even if a recessed part is a non-penetrating structure, the side surface can be measured.

1 is a structural diagram showing a non-contact concave shape measuring apparatus according to a first embodiment of the present invention. The structure figure which shows the principal part of the non-contact recessed part shape measuring apparatus which concerns on 2nd Embodiment of this invention. The structure figure which shows the non-contact recessed part shape measuring apparatus which concerns on 3rd Embodiment of this invention.

(First embodiment)
FIG. 1 is a diagram showing a first embodiment of the present invention. In the figure, XY is two directions orthogonal to each other on a horizontal plane, and Z is a vertical direction perpendicular to XY.

  A measurement workpiece as a measurement target in the present embodiment is a block 1, and a groove (concave portion) 2 having a narrow width D is formed in the Y direction. The block 1 is placed on a Y-axis stage (not shown) and can move in the Y direction.

  A non-contact concave shape measuring device 3 is installed on the block 1 and can be moved in the Z direction for setting by a gantry (not shown).

  The non-contact concave shape measuring apparatus 3 includes an optical unit 4, a probe unit 5, and a focus adjustment unit 6.

  The optical unit 4 is fixed inside the non-contact concave shape measuring apparatus 3, and the probe unit 5 is movable in the Z direction by the focus adjustment unit 6.

  The optical unit 4 will be described. An optical axis K in the Z direction that matches the depth direction of the groove 2 is set in the optical unit 4. The optical unit 4 is provided with laser light irradiation means 7. The laser light irradiation means 7 irradiates a semiconductor laser as the laser light L, and the laser light L is reflected by the reflection mirror 8 so as to be parallel to the optical axis K. The laser beam irradiation means 7 includes the reflection mirror 8.

  After the laser beam L irradiated in parallel with the optical axis K is taken into the probe unit 5, it returns as scattered light from the probe unit 5 by the structure described later. The scattered light beam is symbolized and expressed by its main axis in the figure.

  An imaging lens 9 and an optical position detection means 10 are installed on the optical axis K of the optical unit 4, and the returned laser light L is condensed through the imaging lens 9 and received by the optical position detection means 10. The The optical position detection means 10 is a split photosensor, and the center portion 10s coincides with the image formation point of the imaging lens 9, and the spot centroid (optical centroid) of the laser light L coincides with the center portion 10s. The output of each photo sensor divided into two is balanced. The balance signal of the optical position detection means 10 is output to the focus adjustment unit 6.

  Next, the probe unit 5 will be described. The probe unit 5 itself can be moved in the Z direction along the optical axis K by the focus adjustment unit 6 which is a servo mechanism.

  The focus adjustment unit 6 is connected to a frame 11 having a U-shaped cross section, an objective lens 13 is fixed to an upper opening 12 of the frame 11, and an upper end of a lens barrel 15 is fixed to a lower opening 14. Since the lens barrel 15 is fixed while protruding downward from the frame 11, there is nothing around it. The width of the frame 11 is larger than the width D of the groove 2, but the diameter d of the lens barrel 15 is smaller. Therefore, the lens barrel 15 can enter the groove 2.

  The lens barrel 15 accommodates relay lenses 16 and 17 therein. The objective lens 13 and the relay lenses 16 and 17 are both located on the optical axis K. The focal length of the objective lens 13 can be extended within the range of the diameter d of the small lens barrel 15 by the relay lenses 16 and 17. Since the objective lens 13 and the lens barrel 15 are integrated with each other by the frame 11, the positional relationship between the objective lens 13 and the lens barrel 15 is unchanged, and the optical performance adjusted first is maintained as it is.

  Next, the operation will be described. First, the entire non-contact concave shape measuring apparatus 3 is lowered by a gantry (not shown), and the lens barrel 15 is inserted into the groove 2. Insert the lens barrel 15 until the tip approaches the bottom surface 2a of the groove 2 to be measured.

  When the setting is completed, the laser light L is irradiated from the laser light irradiation means 7 of the optical unit 4. The irradiated laser beam L is reflected downward by the reflecting mirror 8 and becomes parallel to the optical axis K.

  The laser light L exits from the optical unit 4 and is taken into the probe unit 5 and passes through the objective lens 13 as it is. The laser light L that has passed through the objective lens 13 intersects the optical axis K and is then introduced into the upper relay lens 16. The laser light L that has passed through the upper relay lens 16 is parallel to the optical axis K, and after passing through the lens barrel 15, is irradiated from the lower relay lens 17 to the bottom surface 2 a of the groove 2.

  The laser light L applied to the bottom surface 2a of the groove 2 is reflected and scattered by the bottom surface 2a, and again passes through the relay lenses 16 and 17 in the reverse direction as scattered light to reach the objective lens 13. The laser light L that has passed through the objective lens 13 exits from the probe unit 5, enters the optical unit 4, passes through the imaging lens 9, and is received by the optical position detection means 10.

  When the center of gravity of the laser light L received by the optical position detection means 10 matches the central portion 10s of the optical position detection means 10, the position of the focal point of the laser light L matches the bottom surface 2a. The position of is the same.

  When the laser beam L is deviated from the central portion 10s of the optical position detection means 10, the output from the photo sensor on the deviated side becomes large and the output balance of the two photo sensors is lost. The probe unit 5 is moved in the Z direction until a signal is output from the optical position detection means 10 to the focus adjustment unit 6 and the laser light L matches the central portion 10s. When the laser beam L coincides with the central portion 10s of the optical position detection means 10, the focused state is reached and the movement of the probe unit 5 is stopped. From the amount of movement of the probe unit 5 during this feedback control, the height dimension (unevenness dimension) of the bottom surface 2a in the Z direction can be measured. In the focused state, the laser light L returning from the probe unit 5 is also parallel to the optical axis K, and there is no problem even if the probe unit 5 moves in the Z direction with respect to the optical unit 4.

  In this way, the focus adjustment unit 6 moves the probe unit 5 to adjust the focus of the laser beam L to the bottom surface 2a of the groove portion 2 is autofocus, and the block 1 is translated in the Y direction while autofocus is applied. By doing so, the laser beam L can be scanned along the bottom surface 2a, and a continuous two-dimensional shape in the Y direction of the bottom surface 2a can be obtained.

  According to this embodiment, since the objective lens 13 and the relay lenses 16 and 17 are integrated by the frame 11, even if the diameter d of the lens barrel 15 is reduced, the optical positions of the objective lens 13 and the relay lenses 16 and 17 are reduced. You can keep the relationship accurate. Accordingly, the bottom surface 2a of the groove portion 2 having a narrow width D can be accurately measured.

  In this embodiment, the groove portion 2 extending in the Y direction is taken as an example of the concave portion, but the concave-convex shape of the bottom surface 2a can be measured within a range in which the lens barrel 15 can move even in the case of a hole portion. The groove portion may be arcuate, and the bottom surface of the arcuate groove portion can be continuously measured by rotating the measurement workpiece on the rotary table.

  Further, although an example in which the optical unit 4 and the probe unit 5 are set to the same optical axis K has been shown, a reflecting means is provided between the optical unit 4 and the probe unit 5 so that the optical axis of the optical unit 4 with respect to the probe unit 5 is 90. It may be bent. If the laser beam L enters the probe unit 5 in parallel with the optical axis of the probe unit 5, the optical axis of the optical unit 4 may be bent in any way.

  Furthermore, although the example which moves the block 1 to a Y direction with the Y-axis stage not shown was shown, the block 1 may be fixed and the non-contact recessed part shape measuring apparatus 3 side may be moved relatively.

(Second Embodiment)
FIG. 2 is a diagram showing a second embodiment of the present invention. This embodiment includes the same components as those in the first embodiment. Therefore, components similar to those are denoted by common reference numerals and redundant description is omitted.

  In this embodiment, the groove part 18 is a penetration structure, and the structure for measuring the side surface 18b is shown. Reflecting means 19 is inserted into the groove 18 from the side opposite to the direction in which the lens barrel 15 is inserted, and is installed separately from the probe unit. The reflecting means 19 has a reflecting surface having an angle of 45 degrees with respect to the optical axis K, and the optical axis K of the relay lenses 16 and 17 can be bent at a right angle.

  Although this reflecting means 19 is installed on the optical axis K of the objective lens, it is placed separately from the probe unit, so that the structure of the probe unit remains the same and the laser light L is transmitted through the groove 18. The side surface 18b can be measured by irradiating the side surface 18b.

  While performing autofocus control on the side surface 18b of the groove 18 by the laser light L reflected by the reflecting means 19, if only the block 30 is translated in the Y direction while the reflecting means 19 is left as it is, the laser light L is moved to the side surface 18b. And a continuous two-dimensional shape in the Y-axis direction of the side surface 18b can be obtained. By changing the height of the reflection means 19, the shape of the position of the arbitrary height of the side surface 18b can be measured.

(Third embodiment)
FIG. 3 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, components similar to those are denoted by common reference numerals and redundant description is omitted.

  In the non-contact concave shape measuring device 29 according to this embodiment, the entire direction of the optical unit 20 is 90 degrees different from the previous embodiment, and the laser light L from the laser light irradiation means 7 is in the depth direction of the groove 2. Irradiated in parallel with the first optical axis K1 along the X direction orthogonal to.

  In addition to the objective lens 13 and the lens barrel 15, the optical axis reflecting means 23 is also integrated with the frame 22 of the probe unit 21. The optical axis reflecting means 23 is fixed near the upper opening 24 of the frame 22 and bends the first optical axis K1 to a second optical axis K2 that matches the depth direction of the groove 2. The second optical axis K2 coincides with the center of the objective lens 13, and the laser light L emitted from the optical unit 4 is reflected by the optical axis reflecting means 23 and introduced into the objective lens 13 of the probe unit 21.

  Further, inside the lens barrel 26 fixed to the lower opening 25, a tip reflecting means 27 for bending the second optical axis K2 of the objective lens 13 in a direction perpendicular to the tip of the relay lens 17 is integrally provided. The tip reflecting means 27 is a small reflecting mirror.

  Further, the frame 22 of the probe unit 21 is supported by a focus adjustment unit 28, and this focus adjustment unit 28 makes the entire probe unit 21 not the second optical axis K 2 of the objective lens 13 but the first optical axis K 1 of the optical unit 20. The autofocus control is executed by moving along.

  In this embodiment, the laser light L is emitted downward from the laser light irradiation means 7 of the optical unit 20. The laser light L irradiated downward is reflected horizontally by the reflection mirror 8 and becomes parallel to the first optical axis K1.

  The laser light L exits from the optical unit 20, is introduced into the probe unit 21, is reflected by the optical axis reflecting means 23, and then passes through the objective lens 13 as it is. The laser light L that has passed through the objective lens 13 crosses the second optical axis K2, and is then introduced into the upper relay lens 16. The laser beam L that has passed through the upper relay lens 16 is parallel to the second optical axis K2, passes through the lower relay lens 17, is reflected by the tip reflecting means 27, and is applied to the side surface 2b of the groove portion 2. .

  The laser light L applied to the side surface 2b of the groove 2 is reflected and scattered by the side surface 2b to become scattered light, and is reflected again by the tip reflecting means 27, and then passes through the relay lenses 16 and 17 in the opposite direction to the objective lens. 13 is reached. The laser light L that has passed through the objective lens 13 is reflected by the optical axis reflecting means 23, converges after passing through the imaging lens 9, and is received by the optical position detecting means 10.

  If the laser beam L is deviated from the central portion 10s of the optical position detecting means 10, in order to correct it, a signal is output from the optical position detecting means 10 to the focus adjusting unit 28, and the laser light L is applied to the central portion 10s. The probe unit 28 is moved in the X direction until they match. When the laser beam L coincides with the central portion 10s of the optical position detecting means 10, the focused state is reached and the movement of the probe unit 28 is stopped. From the amount of movement of the probe unit 28 at the time of this feedback control, the uneven size in the X direction of the side surface 2b can be measured. In the focused state, the laser beam L returning from the probe unit 28 is also parallel to the first optical axis K1, and there is no problem even if the probe unit 21 moves in the X direction with respect to the optical unit 20.

  If the block 1 is moved in parallel in the Y direction while autofocusing with the laser light L is applied in this way, the laser light L can be scanned along the side surface 2b, and the two continuous sides in the Y direction of the side surface 2b can be obtained. A dimensional shape can be obtained. By adjusting the insertion degree of the lens barrel 26, the uneven shape at an arbitrary height position of the side surface 2b can be measured along the Y direction.

  According to this embodiment, since the tip reflecting means 27 is integrally provided at the tip of the relay lenses 16 and 17, it is not necessary to prepare a separate reflecting means for measuring the side surface 2b, and the lens barrel 26 is provided. If the concave portion is insertable, the side surface 2b can be measured even if the concave portion has a non-penetrating structure.

1, 30 blocks (measurement work)
2, 18 Groove (recess)
2a Bottom surface 2b Side surface 18b Side surface 3, 29 Non-contact concave shape measuring device 4, 20 Optical unit 5, 21 Probe unit 6, 28 Focus adjustment unit 7 Laser light irradiation means 10 Optical position detection means 11, 22 Frame 13 Objective lens 15, 26 Lens barrel 16, 17 Relay lens 19 Reflecting means 23 Optical axis reflecting means 27 Tip reflecting means K Optical axis K1 First optical axis K2 Second optical axis L Laser light D Groove width d Diameter of lens barrel

Claims (3)

A non-contact concave shape measuring device that measures the bottom surface of a concave portion of a measurement workpiece,
Laser light irradiation means for irradiating laser light parallel to the optical axis that matches the depth direction of the recess, and optical position detection means for receiving the returning laser light parallel to the optical axis through the imaging lens when focused. A fixed optical unit, and
A probe unit in which an objective lens and a lens barrel having a smaller diameter than the objective lens and provided with a plurality of relay lenses are integrated with a frame so that the lens barrel is in a state of being projected along the optical axis. ,
The entire probe unit is moved in the direction of the optical axis so that the focal point of the laser beam coincides with the bottom surface of the concave portion by the position signal from the optical position detecting means in a state where the lens barrel of the probe unit is inserted into the concave portion of the measurement work. A focus adjustment unit
The non-contact recessed part shape measuring apparatus characterized by the above-mentioned. A non-contact concave shape measuring device for measuring a side surface of a concave portion of a measurement workpiece,
Laser light irradiation means for irradiating laser light parallel to the optical axis that matches the depth direction of the recess, and optical position detection means for receiving the returning laser light parallel to the optical axis through the imaging lens when focused. A fixed optical unit, and
A probe unit in which an objective lens and a lens barrel having a smaller diameter than the objective lens and provided with a plurality of relay lenses are integrated with a frame so that the lens barrel is in a state of being projected along the optical axis. ,
In a state where the lens barrel of the probe unit is inserted into the concave portion of the measurement work, the entire probe unit is adjusted so that the focal point of the laser beam reflected by the reflecting means by the position signal from the optical position detecting means matches the side surface of the concave portion. A focus adjustment unit that moves in the direction of the optical axis;
Separately reflecting means disposed in the recess in a state separated from the probe unit and bending the optical axis of the probe unit in a right angle direction;
The non-contact recessed part shape measuring apparatus characterized by the above-mentioned. A non-contact concave shape measuring device for measuring a side surface of a concave portion of a measurement workpiece,
Laser light irradiation means for irradiating laser light parallel to the first optical axis perpendicular to the depth direction of the recess, and light for receiving the returning laser light parallel to the first optical axis through the imaging lens when focused. A fixed optical unit comprising position detection means;
An optical axis reflecting means that bends the first optical axis to a second optical axis that matches the depth direction of the recess, an objective lens, a plurality of relay lenses having a smaller diameter than the objective lens, and a second objective lens at the tip. A probe unit in which a lens barrel having a tip reflecting means that bends the optical axis in the first optical axis direction is integrated with a frame so that the lens barrel is in a state along the second optical axis,
In a state where the lens barrel of the probe unit is inserted into the concave portion of the measurement work, the entire probe unit is adapted to make the focal point of the laser beam reflected by the tip reflecting means by the position signal from the optical position detecting means coincide with the side surface of the concave portion. A focus adjustment unit that moves the lens in the first optical axis direction;
The non-contact recessed part shape measuring apparatus characterized by the above-mentioned.

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