JP5209440B2 - Shape measuring probe - Google Patents

Description

  The present invention relates to a shape measuring probe that measures the shape of an object to be measured by displacement of a contact.

The shape measuring probe is a device having a contact that contacts the object to be measured and measuring the shape of the object to be measured by displacement of the contact.
Conventionally, probes having various structures have been proposed as such shape measuring probes (for example, Patent Documents 1 to 3).

Patent document 1 aims at making damage to a to-be-measured object and a contact detection part very small compared with the past.
Therefore, as shown in FIG. 9, this touch signal probe includes a coil spring 53 that biases the movable member 52 held so as to be relatively movable by the holding member 51 toward the stylus 50, and an excitation that moves the anti-biasing direction. A coil 54, a fixed yoke 55, and an armature 56 are provided. When the stylus 50 comes into contact with the object to be measured, a current is supplied to the exciting coil 55 by the signal processing unit 57 and the drive control unit 58, and the movable member 52 moves in the counter-biasing direction away from the object to be measured by the magnetic attraction force. An escape operation is performed. As a result, the time during which the contact detection unit and the object to be measured are in contact with each other is very short, and damage due to contact is reduced.
In this figure, 59 is a control device, and 60 is a drive device.

Patent Document 2 aims to prevent attenuation of an electric signal and to extract a stable electric signal to further reduce the size.
Therefore, as shown in FIG. 10, the measurement probe 61 is made of a conductive metal, and includes a block 62 having a probe portion 66 and a spiral spring 65 formed by a V groove (spiral groove) 63. In the V-groove 63, the vertex 64 of the V-groove exists on the inner side surface 67, and the spiral spring 65 is in spiral contact with the probe portion 66 as the center via the vertex 64 of the V-groove. When the probe portion 66 contacts and presses the object to be measured to take out an electric signal of the object to be measured, the vertical surface 68 parallel to the pressing direction slides on the inclined end portion 69 without leaving the inclined end portion 69. The length of the vertical surface 68 in the F direction is set as the stroke of the spiral spring 65, and the contact is maintained. Moreover, the electrical signal of the taken-out measured object flows directly in the pressurizing direction through the spiral springs 65 that are in contact with each other without flowing spirally through the spiral spring 65.

Patent Document 3 aims to reduce the load on the surface of the object to be measured.
Therefore, as shown in FIG. 11, this contact probe includes a measuring element 70 having a contact portion 71 that contacts the surface of the object to be measured, a detection sensor that detects the displacement of the measuring element 70, and an axis of the measuring element 70. The elastic plate is disposed substantially orthogonal to the direction, and includes a support plate 72 that supports the base end side of the measuring element 70, and a stylus displacement means 73 that displaces the measuring element 70. The stylus displacement means 73 includes actuators 73 to 76 that apply stress to the support plate 72 to change the amount of elastic deformation of the support plate 72 at each point.
In this figure, 77 is a reflection mirror, 78 is an illumination optical system, and 79 is an optical sensor.

Similar to the shape measurement probe, an atomic force microscope (AFM) that detects an atomic force acting on a probe and a sample is known as a device for obtaining the shape of the sample surface. In the atomic force microscope, as shown in FIG. 12, a probe 81 is attached to the tip of a cantilever spring 82 (cantilever), and the deflection of the cantilever 82 is reflected by irradiating the back surface of the cantilever with the semiconductor laser 83. The laser beam is detected by the position sensor 84. Further, the position change of the cantilever 82 and the sample 85 is controlled by utilizing deformation due to the piezoelectric effect of the piezoelectric actuator 86.
In this figure, 87 is an XY drive circuit, 88 is a feedback circuit, and 89 is a control device.

JP 2001-336922 A, “Touch Signal Probe” Japanese Patent Application Laid-Open No. 2003-248018, “Measurement Probe, and Manufacturing Method of the Measurement Probe” JP 2007-205998 A, “Contact Probe and Shape Measuring Device”

  In the touch signal probe of Patent Document 1, when the stylus 50 comes into contact with the object to be measured, the movable member 52 moves in the counter-biasing direction away from the object to be measured by the magnetic attraction force, so that the escape operation is performed. Therefore, it cannot be used as a shape measuring probe for measuring the shape of the object to be measured.

  The measurement probe of Patent Document 2 can extract an electrical signal of the object to be measured by contacting and pressurizing the object to be measured with the probe unit 66, but cannot detect the displacement of the probe part. Cannot be used.

In the contact probe of Patent Document 3, since the proximal end side of the measuring element 70 is fixed to the support plate 72, the displacement resistance of the measuring element 70 is large and the measuring element is displaced three-dimensionally, so that the axial component can be detected. Since the allowable displacement of the probe is small, there is a problem that the probe and the support plate are easily damaged by the overrun of the probe.
In general, the conventional shape measurement probe has a large minimum detection force (for example, 50 mgf or more), and when the tip of the probe is sharp, the surface pressure is too high and scratches the object to be measured. Shape measurement was not possible.

On the other hand, in the atomic force microscope, the pressing force of the cantilever 82 is a micro force (for example, 30 mgf or less) corresponding to the atomic force, and even if the tip of the probe 81 is sharp, the surface pressure is low. There is a feature that can measure a fine shape such as surface roughness without scratching.
However, since the permissible stroke of the cantilever 82 is small (for example, 20 μm or less), the atomic force microscope has a problem that it cannot be measured if the surface of the measurement object 85 is large.

  The present invention has been developed to solve the above-described problems. That is, the objects of the present invention are as follows: (1) The pressing force of the contactor can be set to a minute force corresponding to the interatomic force (for example, 30 mgf or less). (2) The allowable stroke of the contactor is large and can follow the waviness of the measurement surface. (3) The contactor can be prevented from being damaged by the probe overrun. (4) The contactor is movable. An object of the present invention is to provide a shape measuring probe having a small weight and high followability for high speed measurement.

According to the present invention, a probe main body movable along the upper surface of the object to be measured;
A contact whose lower end is in contact with the upper surface of the object to be measured, a cylindrical intermediate shaft that extends vertically upward from the contact, and a flange that is provided at the upper end of the intermediate shaft and has a larger maximum diameter than the intermediate shaft With a stylus,
A stylus holder that is attached to a lower end of the probe body and guides the stylus to be movable in a vertical direction;
A disc-shaped self-weight reducing spring that is sandwiched between the upper surface of the stylus holder and the lower surface of the flange, and biases the flange upward.
There is provided a shape measuring probe comprising a position detection sensor attached to the probe main body and detecting a displacement of the upper surface of the collar portion.

  According to a preferred embodiment of the present invention, the self-weight reducing spring has an outer peripheral portion that contacts the upper surface of the stylus holder and an inner peripheral surface that has a central hole through which the intermediate shaft of the stylus passes and contacts the lower surface of the flange portion. Three or more concentric and circumferentially equidistant helical springs, the inner ends of which are integrally connected to the inner peripheral portion and extend outwardly in a spiral shape, and the outer ends are integrally connected to the outer peripheral portion. It consists of.

  The self-weight reducing spring is provided between the inner peripheral portion and the outer peripheral portion, and has three or more concentric spiral through grooves extending outwardly in a spiral manner therebetween.

  Further, the self-weight reducing spring has an inner peripheral portion whose outer peripheral portion has a predetermined force smaller than the stylus's own weight when the inner peripheral portion is positioned at the same height as the outer peripheral portion. On the other hand, it is formed by offsetting upward in the axial direction of the stylus.

  In addition, a stylus stopper attached to the probe main body and positioned at a predetermined interval above the collar portion is provided.

According to another preferred embodiment of the present invention, further comprising a disk-like position return spring that is sandwiched between the probe body and the upper surface of the flange, and biases the flange downward.
The position return spring includes an outer peripheral portion fixed to the probe main body, an inner peripheral portion having a central hole corresponding to the central portion of the upper surface of the flange portion, and an inner end being in contact with the outer peripheral portion of the upper surface of the flange portion. It consists of three or more concentric spiral springs that are integrally connected to the peripheral part and extend outwardly in a spiral shape and whose outer ends are integrally connected to the outer peripheral part.

  According to the configuration of the present invention, since the stylus is guided by the stylus holder attached to the lower end of the probe main body so as to be movable in the vertical direction, the position detection sensor (for example, a laser sensor) detects the stylus from the displacement of the upper surface of the buttock. Axial displacement can be accurately measured.

In addition, the disc-shaped self-weight reducing spring sandwiched between the upper surface of the stylus holder and the lower surface of the stylus collar urges the stylus collar upward, so that the pressing force of the contact corresponds to the atomic force. Can be set to a minute force (for example, 30 mgf or less), thereby preventing damage to the object to be measured and measuring a fine shape such as surface roughness.
In particular, according to a preferred embodiment of the present invention, the inner peripheral portion that contacts the lower surface of the flange portion is biased upward by three or more spiral spring portions that are concentric and equally spaced in the circumferential direction. The stylus can be moved smoothly in the vertical direction.

  Further, the stylus is guided by the stylus holder so as to be movable in the vertical direction, and can be lifted freely by 1 mm (1000 μm) or more until the upper surface contacts the stylus stopper, and the axial force acting on the stylus does not exceed its own weight. The contactor has a large allowable stroke, can follow the waviness of the measurement surface, and can prevent damage to the contactor due to probe overrun.

  Further, the movable part is only the stylus and the self-weight reducing spring. The self-weight of the stylus can be arbitrarily reduced (for example, 100 mgf or less), and the movable part of the self-weight reducing spring is a thin spiral spring part (for example, width 0.2 mm, thickness) 0.05 mm), the weight of the movable part is very small and the followability to high-speed measurement can be enhanced.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a front view (A) and a side view (B) of a shape measuring probe according to a first embodiment of the present invention. Note that FIGS. 1A and 1B partially show a cross section.

  In this figure, the shape measuring probe of the present invention includes a probe main body 10, a stylus 12, a stylus holder 14, a self-weight reducing spring 16, and a position detection sensor 18.

The probe body 10 is fixed to a moving head (not shown) that can move three-dimensionally, for example, and is held along the upper surface of an object to be measured (not shown) while holding the axis ZZ of the stylus 12 vertically. It is configured to be movable. The position of the probe body 10 on the three-dimensional coordinates can be detected with sufficiently higher accuracy (for example, resolution: 0.1 μm or less) than the accuracy of fine shape measurement such as surface roughness.
In this example, the position detection sensor 18 is a reflective laser sensor, and is attached to the probe main body 10 to detect the displacement of the upper surface of the stylus 12 in a non-contact manner.
The position detection sensor 18 is not limited to a laser sensor, and may be other position detection sensors as long as the displacement of the upper surface of the stylus 12 can be detected with high accuracy (for example, resolution: 0.1 μm or less).

2A and 2B are an enlarged view (A) and an enlarged view (B) of the main part of FIG. 1 (A).
As shown in this figure, the stylus 12 has a contact 12a, an intermediate shaft 12b, and a flange 12c.
The contact 12a is provided at the lower end of the stylus 12, the tip (lower end) is formed in a tapered shape, and the lower end is in contact with the upper surface of the object to be measured. Further, in this example, a ruby ball (not shown) having a diameter of 0.25 mm is attached to the tip (lower end).
In addition, this invention is not limited to this structure, In the case of fine shape measurements, such as surface roughness, it is good to set the shape of a front-end | tip (lower end) to 2-4 micrometers or less in diameter.

The intermediate shaft 12b is a cylindrical rod-like member and extends vertically upward from the upper end of the contact 12a.
The flange portion 12c is provided at the upper end of the intermediate shaft 12b and has a maximum diameter larger than that of the intermediate shaft. The flange portion 12c has a cylindrical shape in this example, and the upper surface 13a and the lower surface 13b thereof are formed on a plane orthogonal to the axis ZZ of the stylus 12.

  Furthermore, in this example, the upper surface 13a of the collar portion 12c is finished to be a mirror surface, or DLC, gold, silver or the like is vapor-deposited, and the reflectance of the laser from the position detection sensor 18 (in this example, a reflective laser sensor) is increased. It is increasing.

In FIG. 2, the stylus holder 14 is a prefix conical member having a through guide hole 14a in the center, and is attached to the lower end of the probe body 10 with a bolt 15a or the like. The inner shaft 12b of the stylus 12 is formed on the inner surface of the through guide hole 14a. Is movably guided in the vertical direction.
The clearance between the penetrating guide hole 14a and the intermediate shaft 12b is preferably set small as long as the stylus 12 can move up and down smoothly. Further, in order to reduce the sliding resistance between the through guide hole 14a and the intermediate shaft 12b, it is preferable to coat one or both surfaces with lubricity.

In this example, the shape measuring probe of the present invention further includes a stylus stopper 20. The stylus stopper 20 is attached above the stylus holder 14 of the probe main body 10, and the lower surface 20a thereof is positioned above the upper surface 13a of the flange 12c with a predetermined interval. This predetermined interval is preferably set to a probe overrun (for example, sufficiently larger than 0.1 to 0.2 mm, for example, 1 mm or more).
In this example, the stylus stopper 20 includes a prefix conical opening 20b through which the laser beam of the position detection sensor 18 (reflective laser sensor) passes, and a bolt for fixing the stylus stopper 20 to the probe body 10 with a bolt 15b. And a hole 20c.

  FIG. 3 is an exploded view of FIG. In this figure, the self-weight reducing spring 16 is a disc-shaped spring, and is sandwiched between the upper surface of the stylus holder 14 and the flange lower surface 13b of the stylus 12, and urges the flange 12c upward.

4 is an AA arrow view of FIG. 3 (A) and an enlarged view of the main part thereof (B).
As shown in FIG. 4A, the self-weight reducing spring 16 is an integral flat plate including an outer peripheral portion 16a, an inner peripheral portion 16b, and a helical spring portion 16c.

The outer peripheral portion 16 a is a ring-shaped flat plate, and is sandwiched between the upper surface of the stylus holder 14 and the lower end of the probe body 10 in this example, and always contacts the upper surface of the stylus holder 14. The outer peripheral portion 16a is provided with a through hole 17a through which the bolt 15a passes and a through hole 17b through which a positioning pin (not shown) passes.
The inner peripheral portion 16b is a ring-shaped flat plate located inside the outer peripheral portion 16a, has a center hole 16d through which the intermediate shaft 12b of the stylus 12 passes, and an inner edge portion contacts the flange lower surface 13b of the stylus 12.
The spiral spring portion 16c is composed of three or more (three in this example) concentric and circumferentially equidistant spiral members, and the inner ends thereof are integrally connected to the inner peripheral portion 16b. Extends outward spirally, and the outer ends thereof are integrally connected to the outer peripheral portion 16a.

  In the example of FIG. 4B, the three concentric spiral spring portions 16c are shifted from each other in the circumferential direction by 120 °. Further, in this figure, the thick spiral portion 19 is a through groove provided between three concentric spiral spring portions 16c. That is, the self-weight reducing spring 16 has three or more concentric spiral through grooves 19 that are spirally extended between the inner peripheral portion 16b and the outer peripheral portion 16a between the inner peripheral portion 16b and the outer peripheral portion 16a. A spiral spring portion 16c is formed between the grooves.

The above-described self-weight reducing spring 16 applies a photoresist to the surface of a smooth metal plate, exposes and develops a photomask corresponding to three or more concentric spiral through grooves 17, and develops the spiral through grooves 17. By leaving the photoresist only at the locations corresponding to the above, plating a metal such as Ni or Au on the surface of the metal plate, and separating the metal from the surface of the metal plate, it can be precisely manufactured. Hereinafter, this manufacturing method is referred to as “plating manufacturing method”.
In addition, this invention is not limited to this manufacturing method, You may form the spiral through-groove 17 of 3 or more concentric and equally spaced in the circumferential direction by photoetching etc. to the metal plate of predetermined thickness.

  Further, in this example, the self-weight reducing spring 16 is formed such that the inner peripheral portion 16c is offset upward in the axial direction of the stylus 12 with respect to the outer peripheral portion 16a. This forming is set so that the downward force acting on the contact 12a becomes a predetermined force smaller than the weight of the stylus 12 when the inner peripheral portion 16c is positioned at the same height as the outer peripheral portion 16a. In addition, it is preferable to carry out annealing and quenching during the forming.

For example, when the weight of the stylus 12 is 170 mgf, the inner peripheral portion 16c is offset from the outer peripheral portion 16a upward in the axial direction of the stylus 12, and the inner peripheral portion 16c is positioned at the same height as the outer peripheral portion 16a. Is set so that the upward force acting on the contact 12a is 140 mgf.
With this setting, when the inner peripheral portion 16c is positioned at the same height as the outer peripheral portion 16a, the downward force acting on the contact 12a is 30 mgf, which is the difference between the own weight and the spring force.

FIG. 5 is a characteristic diagram of the self-weight reducing spring of the first embodiment actually manufactured. In this figure, the horizontal axis represents displacement, and the vertical axis represents axial force. (A) shows a maximum displacement of about 70 μm, and (B) shows a maximum displacement of about 3.5 mm. Moreover, in each figure, (circle) in a figure is experimental data.
The displacement is defined as 0 (origin) where the contact 12a is not in contact with the object to be measured in the state of being incorporated in the apparatus of FIG. Further, the axial force is an axially upward force acting on the contact 12a.
The self-weight reducing spring 16 is made of Ni having a thickness of 0.049 mm by the plating method described above. In this example, the outer diameter of the spiral spring portion 16c was 10 mm, the width of the spiral spring portion 16c was 0.2 mm, and the width of the spiral through groove 17 was 0.2 mm.

5A and 5B, the axial force y [gf] is exactly proportional to the displacement x [mm] in the range from 0 to about 3.5 mm. There is a relationship. That is, in this range, the spring constant k of the self-weight reducing spring is exactly a constant value 0.2762.
y = 0.762x + 0.0304 (1)

5A, when the inner peripheral portion 16c of the self-weight reducing spring 16 is positioned at the same height as the outer peripheral portion 16a in a free position where the contact 12a does not contact the object to be measured (incorporated in the apparatus of FIG. 1). The downward force acting on the contact 12a is 30 mgf, which is the difference between its own weight and the spring force.
Next, when the contact 12a comes into contact with the upper surface of the object to be measured and the stylus 12 is displaced upward from the free position, the position detection sensor 18 detects the displacement of the collar upper surface 13a. At this time, the downward force acting on the contact 12a increases in proportion to the amount of displacement from 30 mgf. For example, when the desired maximum displacement is 50 μm, the axial force is about 44 mgf.
Furthermore, even if it exceeds a desired maximum displacement (for example, 50 μm), the displacement of the collar upper surface 13a can be detected by the position detection sensor 18.

  From FIG. 5B, since the axial force exceeds its own weight (for example, 170 mgf) at a displacement of about 500 μm, the downward force acting on the contact 12a is only its own weight when the displacement is more than that. Therefore, it can be seen that even if the displacement exceeds about 500 μm, the displacement can be detected, but the contactor 12a is not subjected to a force greater than its own weight.

  According to the configuration of the present invention described above, since the stylus 12 is guided by the stylus holder 14 attached to the lower end of the probe main body 10 so as to be movable in the vertical direction, the position detection sensor 18 (for example, a laser sensor) is used. The axial displacement of the stylus 12 can be accurately measured from the displacement 13a.

Further, since the disc-shaped self-weight reducing spring 16 sandwiched between the upper surface of the stylus holder 14 and the flange lower surface 13b of the stylus 12 urges the flange 12c of the stylus 12 upward, the contact 12a is pressed. The force can be set to a micro force (for example, 30 mgf or less) corresponding to the atomic force, thereby preventing the object to be measured from being scratched and measuring a fine shape such as surface roughness.
In particular, according to the above embodiment, the inner peripheral portion 16b contacting the lower surface 13b of the flange portion 12c is urged upward by the concentric and three or more spiral spring portions 16c that are equidistant in the circumferential direction. The stylus 12 can be moved smoothly in the vertical direction.

  The stylus 12 is guided by the stylus holder 14 so as to be movable in the vertical direction. The stylus 12 can be freely raised by 1 mm (1000 μm) or more until the upper surface contacts the stylus stopper 20, and the axial force acting on the stylus 12 is greater than its own weight. Therefore, the allowable stroke of the contact 12a is large, can follow the waviness of the measurement surface, and can prevent damage to the contact due to overrun of the probe.

  Further, the movable parts are only the stylus 12 and the self-weight reducing spring 16, and the self-weight of the stylus 12 can be arbitrarily reduced (for example, 100 mgf or less), and the movable part of the self-weight reducing spring 16 is a thin helical spring part 16c (for example, width 0). 2 mm and thickness 0.05 mm), the weight of the movable part is very small and the followability to high-speed measurement can be enhanced.

FIG. 6 is an enlarged view of a main part of the shape measuring probe according to the second embodiment of the present invention.
In this example, the shape measuring probe of the present invention further includes a disk-like position return spring 22 that is sandwiched between the probe main body 10 and the collar upper surface 13a and biases the collar 12c downward.
The position return spring 22 has substantially the same shape as the above-described self-weight reducing spring 16 and includes an outer peripheral portion, an inner peripheral portion, and a helical spring portion.
The outer peripheral portion of the position return spring 22 has substantially the same shape as the outer peripheral portion of the self-weight reducing spring 16. In this example, the outer peripheral portion is sandwiched between the stylus stopper 20 and the probe main body 10 and fixed to the probe main body 10. .
The inner peripheral portion of the position return spring 22 has substantially the same shape as the inner peripheral portion of the self-weight reducing spring 16, but in this example, it has a center hole corresponding to the detection surface by the position detection sensor 18, Contact the upper surface 13a.
The helical spring portion of the position return spring 22 has substantially the same shape as the helical spring portion of the self-weight reducing spring 16, but in this example, the inner peripheral portion is lower than the outer peripheral portion in the axial direction of the stylus 12. Formed with an offset.
In this example, the offset amount of the inner peripheral portion 16c of the self weight reducing spring 16 in the axial direction upward is larger than that in the first embodiment, and the collar portion 12c is supported by the self weight reducing spring 16 in a state where the self weight of the stylus 12 is supported. And the position return spring 22.
Note that the spring constants and offset amounts of the self-weight reducing spring 16 and the position return spring 22 may be the same or different.
Other configurations are the same as those of the first embodiment.

With the above-described configuration, in FIG. 6, in the free position where the contact 12a does not come into contact with the object to be measured, the flange 12c is held between the weight reducing spring 16 and the position return spring 22 and balanced, so the contact 12a There is no downward force acting on (zero).
Next, when the contact 12a comes into contact with the upper surface of the object to be measured and the stylus 12 is displaced upward from the free position, the position detection sensor 18 detects the displacement of the upper surface of the buttock. At this time, the downward force acting on the contact 12 a becomes an axial force determined by the extension of the self-weight reducing spring 16 and the contraction of the position return spring 22. Therefore, by setting the spring constants and offset amounts of the self-weight reducing spring 16 and the position return spring 22, the maximum value of the axial force can be set to 30 mgf or less in a desired measurement range (for example, maximum displacement 50 μm).
Furthermore, even if the desired maximum displacement is exceeded, the position detection sensor 18 can detect the displacement of the upper surface of the buttocks.

The shape measuring probe of the second embodiment shown in FIG. 6 has a stylus because the flange 12c is sandwiched between the self-weight reducing spring 16 and the position return spring 22 in a free position where the contact 12a does not contact the object to be measured. Even if the 12 axis lines ZZ are oriented in a direction other than vertical (horizontal or oblique), they can be used similarly.
In the shape measurement probe of the second embodiment, the return force of the position return spring 22 increases as the displacement increases, but the response characteristics can be improved accordingly.
Other effects are the same as those of the first embodiment.

FIG. 7 is a plan view (A) of the self-weight reducing spring of the second embodiment and an enlarged view (B) thereof.
The self-weight reducing spring 16 is made of Ni having a thickness of 0.048 mm by the plating method described above. In this example, the outer diameter of the spiral spring portion 16c was 10 mm, the width of the spiral spring portion 16c was 0.3 mm, and the width of the spiral through groove 17 was 0.05 mm.
Other configurations are the same as the self-weight reducing spring of the first embodiment.

FIG. 8 is a characteristic diagram of the self-weight reducing spring of the second embodiment. In this figure, the horizontal axis represents displacement, the vertical axis represents axial force, (A) shows a maximum displacement of up to about 55 μm, and (B) shows a maximum displacement of up to about 5.5 mm. Moreover, in each figure, (circle) in a figure is experimental data.
The displacement is defined as 0 (origin) where the contact 12a is not in contact with the object to be measured in the state of being incorporated in the apparatus of FIG. Further, the axial force is an axially upward force acting on the contact 12a.
8A and 8B, the axial force y [gf] is accurately proportional to the displacement x [mm] in the range from 0 to about 5.5 mm. There is a relationship. That is, within this range, the spring constant k of the self-weight reducing spring was exactly a constant value 0.2149.
y = 0.2149x + 0.0343 (1)
Other configurations and effects are the same as those of the first embodiment.

The configuration of the self-weight reducing spring 16 is not limited to the above-described embodiment, and the outer diameter of the spiral spring portion 16c and the width of the spiral spring portion 16c are as long as the number of spiral spring portions is 3 or more. , And the width of the spiral through groove 17 can be freely set.
Therefore, the spring constant k of the self-weight reducing spring can be set to a value (for example, 0.1 or less) smaller than that of the above-described embodiment by this setting.
Further, in the above-described embodiment, the axial force y [gf] when the displacement x [mm] is 0 is manufactured with the target of 30 mgf in the state of being incorporated in the apparatus of FIG. The value can also be set to an arbitrary value (for example, 0 mgf).

  As described above, the shape measuring probe of the present invention can set (1) the pressing force of the contactor to a micro force (for example, 30 mgf or less) corresponding to the interatomic force, thereby preventing damage to the object to be measured, Fine shape measurement such as surface roughness can be performed, (2) The allowable stroke of the contactor is large and can follow the waviness of the measurement surface, (3) Damage to the contactor due to probe overrun can be prevented, (4 ) Excellent effects such as a small weight of the movable part such as a contact and high follow-up performance for high-speed measurement can be obtained.

  In addition, this invention is not limited to the Example and embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.

It is the front view (A) and side view (B) of the shape measuring probe of 1st Embodiment by this invention. They are the A section enlarged view (A) and its principal part enlarged view (B) of FIG. 1 (A). FIG. 3 is an exploded view of FIG. It is an AA arrow line view (A) of FIG. 3, and its principal part enlarged view (B). It is a characteristic view of the self-weight reduction spring of 1st Embodiment. It is a principal part enlarged view of the shape measuring probe of 2nd Embodiment by this invention. It is the top view (A) of the self weight reduction spring of 2nd Embodiment, and the principal part enlarged view (B). It is a characteristic view of the self-weight reduction spring of 2nd Embodiment. 10 is a schematic diagram of a touch signal probe disclosed in Patent Document 1. FIG. 10 is a schematic diagram of a measurement probe disclosed in Patent Document 2. FIG. It is a schematic diagram of the contact probe of patent document 3. It is a schematic diagram of an atomic force microscope.

Explanation of symbols

10 probe body, 12 stylus,
12a contact, 12b intermediate shaft, 12c buttocks,
13a upper surface, 13b lower surface,
14 Stylus holder, 14a Through guide hole,
15a, 15b bolt,
16 Weight reduction spring,
16a outer peripheral part, 16b inner peripheral part, 16c helical spring part,
17a, 17b through holes,
18 Position detection sensor (laser sensor),
19 spiral through groove, 20 stylus stopper,
20a bottom surface, 20b opening, 20c bolt hole,
22 Position return spring

Claims (6)

A probe body movable along the upper surface of the object to be measured;
A contact whose lower end is in contact with the upper surface of the object to be measured, a cylindrical intermediate shaft that extends vertically upward from the contact, and a flange that is provided at the upper end of the intermediate shaft and has a larger maximum diameter than the intermediate shaft With a stylus,
A stylus holder that is attached to a lower end of the probe body and guides the stylus to be movable in a vertical direction;
A disc-shaped self-weight reducing spring that is sandwiched between the upper surface of the stylus holder and the lower surface of the flange, and biases the flange upward.
A shape measuring probe, comprising: a position detection sensor attached to the probe main body and detecting a displacement of the upper surface of the collar portion.   The self-weight reducing spring includes an outer peripheral portion that contacts the upper surface of the stylus holder, an inner peripheral portion that has a central hole through which an intermediate shaft of the stylus passes and an inner end that contacts the lower surface of the flange portion, and an inner end thereof is an inner peripheral portion. It is composed of three or more spiral spring parts that are integrally connected and extend outwardly in a spiral shape and whose outer ends are integrally connected to an outer peripheral part and are equidistantly spaced in the circumferential direction. Item 2. The shape measuring probe according to Item 1.   The self-weight reducing spring is provided between the inner peripheral portion and the outer peripheral portion, and has three or more concentric spiral through grooves extending outwardly in a spiral manner between the inner peripheral portion and the outer peripheral portion. The shape measuring probe as described.   The self-weight reducing spring has an inner peripheral portion on the outer peripheral portion so that a downward force acting on the contact when the inner peripheral portion is positioned at the same height as the outer peripheral portion is a predetermined force smaller than the stylus's own weight. On the other hand, the shape measuring probe according to claim 1, wherein the probe is formed by being offset upward in the axial direction of the stylus.   The shape measuring probe according to claim 1, further comprising a stylus stopper attached to the probe main body and positioned at a predetermined interval above the collar portion. Furthermore, a disc-shaped position return spring that is sandwiched between the probe main body and the upper surface of the flange and biases the flange downward.
The position return spring includes an outer peripheral portion fixed to the probe main body, an inner peripheral portion having a central hole corresponding to the central portion of the upper surface of the flange portion, and an inner end being in contact with the outer peripheral portion of the upper surface of the flange portion. It is composed of three or more spiral spring parts that are integrally connected to the peripheral part and extend outward in a spiral shape and whose outer ends are integrally connected to the outer peripheral part and are equidistantly spaced in the circumferential direction. The shape measuring probe according to claim 1.

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