JP5054318B2 - Displacement sensor, shape measuring device - Google Patents

Description

  The present invention relates to a displacement sensor and a shape measuring device. For example, the present invention relates to a displacement sensor that detects a displacement amount and a displacement direction of a probe.

  Measuring devices that scan the surface of the object to be measured and measure the surface properties and three-dimensional shape of the object to be measured are known, such as a roughness measuring machine, a contour shape measuring machine, a roundness measuring machine, and a three-dimensional measuring machine. It has been known. In such a measuring apparatus, a contact probe is used as a displacement sensor that detects the surface of the object to be measured based on the minute displacement of the contact part when the contact part contacts the surface of the object to be measured (Patent Document 1).

FIG. 16 shows a configuration of the shape measuring apparatus 10 using a contact probe.
The shape measuring apparatus 10 includes a contact probe 11 and a drive mechanism 12 that moves the contact probe 11 three-dimensionally along the surface of the object to be measured. As shown in FIG. 17, the contact probe 11 includes a stylus 13 having a contact portion 14 at a distal end and a sensor main body portion 15 that supports the proximal end of the stylus 13. The sensor main body 15 supports the stylus 13 so as to be displaceable within a certain range in the xp, yp, and zp directions, and detects the amount of displacement of the stylus 13.

For example, the sensor main body 15 includes a plurality of light sources and a plurality of optical sensors that are combined with each of the light sources and detect a light receiving position. Then, the amount of change in the optical path of the light from the light source due to the displacement of the stylus 13 is detected by the optical sensor, and the three-dimensional displacement of the stylus 13 is detected by combining the detection results of the plurality of optical sensors.
In order to detect the three-dimensional displacement of the stylus 13 with such a plurality of light sources and a plurality of optical sensors, the axial displacement of the probe is measured by a triangulation displacement sensor and tilted by an autocollimator optical system. (For example, refer to Patent Document 2).

  In such a configuration, the contact probe 11 is moved along the surface of the object to be measured by the drive mechanism 12 in a state where the contact portion 14 is in contact with the surface of the object to be measured with the reference pressing amount Δr. At this time, the movement locus of the contact probe 11 is obtained from the driving amount of the drive mechanism 12, and the surface shape of the object to be measured is obtained from the movement locus of the contact probe 11.

Japanese Patent Publication No. 2000-39302 Japanese Patent Publication No. 2000-304529 (paragraph (0014), FIG. 5)

However, since the conventional contact probe 11 uses a plurality of light sources and a plurality of optical sensors, it is necessary to calibrate individual differences between these optical components, which is very time-consuming and difficult to achieve high accuracy. .
In addition, if a plurality of optical sensors are provided, the installation space is increased, which leads to an increase in the size of the probe and further increases in cost.

  An object of the present invention is to provide a displacement sensor that has a simple configuration and detects the displacement of a probe with high accuracy, and a shape measuring device including the displacement sensor.

The displacement sensor of the present invention includes a measuring element, and a sensor main body that supports the measuring element in a displaceable manner and detects a displacement amount and a displacement direction of the measuring element, and the sensor main body includes the measuring element. Support means for supporting displaceability, two or more light sources, an optical sensor that receives light and outputs a light reception signal corresponding to the amount of received light through photoelectric conversion, and the optical sensor that emits light emitted from each of the light sources An optical shift unit that shifts the incident position of the probe according to the displacement of the probe, and a signal processing unit that calculates a displacement amount and a displacement direction of the probe based on the received light signal, and the two or more light sources Emits modulated light, each of which is modulated differently, toward the light shift means, and the optical sensor is divided into a plurality of light receiving parts by a plurality of dividing lines, and the received light quantity for each of the light receiving parts. Received light Outputs, the signal processing unit includes a separating means for respectively separating the signals of the respective modulated lights from the light receiving signal outputted from the optical sensor, on the basis of the signals of the modulated light split by said separating means Shift amount calculating means for calculating the shift amount of the incident position where each modulated light is incident on the optical sensor; and a probe displacement calculating unit for calculating the displacement of the probe based on the shift amount of each modulated light. It is characterized by that.

  In such a configuration, modulated light that is modulated differently from each light source is emitted, and the emitted light is received by the optical sensor. At this time, when the probe is displaced, the modulated light from each light source is shifted by the light shift means according to the displacement of the probe, and the incident position on the optical sensor is changed. When light is received by the optical sensor, a light reception signal is output according to the amount of received light. The received light signal is sent to the signal processing unit for signal processing. At this time, the signal of each modulated wave is separated from the received light signal by the separating means of the signal processing unit. Then, the shift amount calculation means calculates the shift amount of each modulated wave on the optical sensor based on the signal of each modulated wave thus separated. Based on the shift amount of each modulated wave, the displacement of the probe is calculated by the probe displacement calculator. For example, the displacement of the tracing stylus is obtained by combining simultaneous shift amounts of the modulated waves and establishing simultaneous equations with the displacement of the tracing stylus as an unknown.

According to such a configuration, by using the light from each light source as a modulated wave, even if all the modulated waves are received by one optical sensor, the signal of each modulated wave can be separated from the received light signal. Therefore, sufficient information for specifying the three-dimensional displacement of the probe can be obtained. Therefore, only one optical sensor that receives light is used, and a plurality of optical sensors are not used as in the prior art. Therefore, in the present invention, it is not necessary to calibrate a plurality of optical sensors, and the labor of measurement is greatly simplified. can do.
Furthermore, since the number of parts can be reduced by using one optical sensor, the displacement sensor can be simplified and the displacement sensor can be downsized.
Also, by converting the light from the light source into a modulated wave, even if disturbance noise is superimposed on the received light signal due to vibration or electrical noise applied to the displacement sensor, the separating means separates the modulated wave signal from the received light signal. The influence of disturbance noise can be eliminated at the stage of generating. In particular, if the detection resolution is improved, it is likely to be affected by disturbance noise. However, according to the present invention, the disturbance noise can be eliminated, so that the detection resolution can be improved and the accuracy can be improved. Can do.
In addition, the optical sensor is divided into a plurality of light receiving units by a plurality of dividing lines and outputs a light reception signal corresponding to the amount of light received for each light receiving unit. For example, the optical sensor is divided into crosses. If the line is divided into four light receiving parts and these dividing lines are made to correspond to the x-axis and the y-axis, the shift amount of the incident position of the light is two-dimensional based on the change of the light-receiving signal output from the four divided regions. It can be easily obtained in an orthogonal coordinate system.
As described above, the displacement amount of the probe can be calculated by combining the results of calculating the shift amount of the incident position of each modulated wave on the optical sensor in the two-dimensional coordinate system.

  As an example of the separating means, a configuration in which a band pass filter and a demodulating circuit are combined can be given.

  Note that the number of divisions and how to divide the optical sensor are not particularly limited as long as the change in the incident position of light can be detected two-dimensionally.

  In the present invention, the method for modulating the light from the light source is preferably any one of amplitude modulation, phase modulation, and frequency modulation.

  In such a configuration, regardless of whether the light modulation method is amplitude modulation, phase modulation, or even frequency modulation, each modulated wave is detected from the light reception signal of the optical sensor by a predetermined detection method. Since the signals can be separated, the shift amount of each modulated wave can be obtained. Then, the displacement of the probe can be obtained based on the shift amount of each modulated wave.

  In this invention, it is preferable that the said light shift means is an optical element which changes according to the displacement of the said probe, and reflects or refracts the light from the said light source.

  In such a configuration, when the probe is displaced, the optical element is displaced according to the displacement of the probe. Then, the reflection direction or refraction direction of light by the optical element changes. And the incident position of the light to an optical sensor is shifted.

  In the present invention, it is preferable that the optical element is a reflecting mirror attached to the measuring element via the support means and displaced together with the measuring element to change a position and a reflecting surface angle.

  In such a configuration, the reflection mirror, which is an optical element, is displaced by the displacement of the probe, and the reflection surface position and the reflection surface angle of the reflection mirror change. Then, when the light reflected by the reflecting mirror enters the optical sensor, the position of the light incident on the optical sensor is shifted according to the displacement of the probe.

  The reflection mirror may be a plane mirror or a polygonal pyramid having an inclined surface such as a triangular pyramid or a quadrangular pyramid. When the reflecting mirror is a plane mirror, the incident angle of the light to the optical sensor changes as the tilt angle of the reflecting surface changes or the reflecting surface moves up and down. Further, when the reflecting mirror is a polygonal pyramid having an inclined surface, the incident position of the light to the optical sensor also changes due to the rotation or two-dimensional displacement of the reflecting mirror. The displacement amount of freedom can be obtained independently.

  In the present invention, it is preferable that the support means is a plate having elasticity, and has a plurality of cut lines with point symmetry with respect to the center of the plate, and supports the measuring element at the center of the plate.

In such a configuration, the plate acts as an elastic leaf spring by having a plurality of cut lines. By supporting the measuring element by this plate, the measuring element is supported so as to be displaceable while being given an urging force to return to the reference position. In addition, the cutting line is provided symmetrically with the center of the plate as the center of point symmetry, so that the measuring element for the same stress can be obtained even when the measuring element is displaced from any direction without giving anisotropy to the measuring element. Can be made the same amount of displacement. Further, as a configuration for supporting the measuring element while allowing the three-dimensional displacement of the measuring element, a structure including an x-axis direction sliding mechanism, a y-direction sliding mechanism, and a z-direction sliding mechanism including a guide rail and a slider is known. However, in such a configuration, the configuration is complicated, and anisotropy tends to occur in the sliding mechanism in each direction.
In this respect, the support means of the present invention has a simple configuration and can support the measuring element so that it can be displaced without anisotropy.

As the optical element, a reflection mirror may be attached to the support means.
When the base end of the probe is supported by such a plate-like support means, the rotation of the probe around the central axis and the two-dimensional displacement of the probe are restricted, and the probe only moves up and down and swings. Will be allowed. Accordingly, since the degree of freedom of the measuring element is 3 (vertical direction, rotation about the x axis, rotation about the y axis), even if the reflecting mirror is a plane mirror, the degree of freedom is specified for each of the measuring elements. Can be obtained.

  The shape measuring apparatus according to the present invention includes the displacement sensor, a drive mechanism that moves the displacement sensor relative to the object to be measured to bring the displacement sensor into contact with the object to be measured, and the displacement sensor by the drive mechanism; A drive sensor that detects a relative displacement amount with the object to be measured, and an analysis unit that analyzes the shape of the object to be measured based on the displacement sensor and a detection value by the drive sensor.

  According to the displacement sensor, the displacement direction and displacement amount of the measuring element can be detected. Therefore, the measuring element is moved in contact with the surface of the object to be measured with a predetermined pressing pressure, and the locus of the measuring element at this time is determined. By detecting, the surface shape of the object to be measured can be measured.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be illustrated and described with reference to reference numerals attached to respective elements in the drawings.
(First embodiment)
A contact probe 100 as a first embodiment according to the displacement sensor of the present invention will be described.
FIG. 1 is a perspective view illustrating the inside of the contact probe 100 in order to show the entire configuration.
FIG. 2 is a cross-sectional view of the contact probe 100 cut in the vertical direction.
For the following explanation, the z-axis is taken in the vertical direction of the paper in FIG. 2, the x-axis is taken in the horizontal direction of the paper, and the y-axis is taken in the vertical direction of the paper.

  The contact probe 100 includes a measuring element 200 that is displaced by contact pressure when abutting against the surface of the object to be measured, a sensor main body 300 that supports the measuring element 200 so as to be displaceable, and detects the displacement of the measuring element 200. Is provided.

The measuring element 200 includes a stylus 210 and a contact portion 220 provided at the tip of the stylus 210. The base end of the stylus 210 is attached to the sensor main body 300, and the measuring element 200 is supported in a state of hanging from the sensor main body 300.
A direction along the axis of the stylus 210 in a reference state in which the measuring element 200 is not displaced is referred to as a center line direction A.

  The sensor main body 300 includes a cylindrical housing part 310 having a lower end opened and a storage space 311 inside, and a support plate (supporting means) 320 that supports the base end of the measuring element 200 on the lower end side of the housing part 310. Displacement detecting means 400 for detecting the displacement of the measuring element 200.

The housing part 310 includes a support plate 320 and a displacement detection unit 400 in an internal storage space 311.
A flexible sheet material 312 that closes the opening and prevents intrusion of dust and the like into the inside is disposed on the lower end side of the housing portion 310. The measuring element 200 is disposed in a state where the sheet material 312 is inserted.

The support plate 320 is a circular metal plate, and a peripheral end portion is fixed to the housing portion 310. The measuring element 200 is attached and fixed to the lower surface side of the support plate 320 via the reinforcing plate 324 at the center of the support plate 320.
Here, FIG. 3 is a top view of the support plate 320.
The support plate 320 has three cut lines 321, 321, and 321, and the three cut lines 321, 321, and 321 are provided symmetrically with the center C 1 of the support plate 320 as the center of point symmetry. Each incision line 321 has a circular arc part 322 and a straight line part 323, and is bent in a substantially square shape. Three cut lines 321, 321, and 321 are arranged around the center C 1 of the support plate 320, and the straight line part 323 of the other cut line 321 is located inside the arc part 322 of one cut line 321 (FIG. 3). reference). The support plate 320 can be displaced up and down at the part of the cut line 321, and the measuring element 200 is swingably supported by attaching the measuring element 200 to the center of the supporting plate 320.

  The measuring element 200 supported by the support plate 320 has a contact portion 220 that can be displaced vertically (Δz direction), left and right (Δx direction), and back and forth (Δy direction). On the other hand, in the probe 200, the rotation of the stylus 210 around the central axis and the displacement of the stylus base end 210A in the plane direction of the support plate 320 are restricted. That is, the measuring element 200 is allowed to be displaced in the Z direction, swinged in the X direction around the base end, and swinged in the Y direction around the base end.

The displacement detection unit 400 receives a reflection mirror (optical element) 410 that is displaced according to the displacement of the measuring element 200, an irradiation optical system 420 that irradiates light toward the reflection mirror 410, and reflected light from the reflection mirror 410. And a signal processing unit 500 that calculates a displacement amount and a displacement direction of the measuring element 200 based on a light reception signal output from the light receiving optical system 430.
The reflection mirror 410 and the light receiving optical system 430 are arranged along the center line A.

  The reflection mirror 410 is disposed substantially at the center of the support plate 320 on the upper surface side of the support plate 320. When the measuring element 200 is displaced, the center of the support plate 320 is displaced together with the measuring element 200. Therefore, the reflecting mirror 410 is also displaced according to the displacement of the measuring element 200, and the position and angle of the reflecting surface 411 are changed.

The irradiation optical system 420 includes two light sources 421A and 421B that emit light.
The two light sources 421A and 421B are spaced apart in the x direction with the optical sensor 440 in between. The light sources 421 </ b> A and 421 </ b> B emit light toward the reflection mirror 410, and the posture is such that the light reflected by the reflection mirror 410 is incident on the center of the optical sensor 440 in a reference state where the probe 200 is not displaced. Adjusted.
In FIG. 2, the light sources 421 </ b> A and 421 </ b> B cause light to enter the reflection mirror 410 at an incident angle θ.
For example, LEDs can be used as the light sources 421A and 421B.
The two light sources 421A and 421B emit modulated light that is amplitude-modulated at different frequencies.
In FIG. 1 and FIG. 2, for example, modulated light Sa amplitude-modulated at frequency fa is emitted from a light source 421A disposed on the −x side, and amplitude modulated at frequency fb from a light source 421B disposed on the + x side. The modulated light Sb thus emitted is emitted. (However, fa ≠ fb)

The optical sensor 440 receives light from the reflection mirror 410 and outputs a light reception signal by photoelectric conversion.
FIG. 4 is a view of the optical sensor 440 as seen from the light receiving surface side.
The optical sensor 440 is divided into four by a dividing line 445 along the x axis and the y axis, and includes first to fourth light receiving units 441 to 444.
Here, the light receiving unit disposed at the position (+ y, −x) is referred to as the first light receiving unit 441, and the second light receiving unit 442 is disposed at the position (+ y, + x), and (−y, + x) The light receiving unit disposed at the position is referred to as a third light receiving unit 443, and the light receiving unit disposed at the position (−y, −x) is referred to as a fourth light receiving unit 444.

The signal processing unit 500 calculates the shift direction and shift amount of the light from the reflection mirror 410 based on the light reception signals output from the light receiving units 441 to 444 of the optical sensor 440, and based on the shift direction and shift amount of the light. Thus, the displacement amount and displacement direction of the measuring element 200 are calculated.
FIG. 5 is a diagram illustrating a configuration of the signal processing unit 500.
The signal processing unit 500 separates and extracts the modulated light signals Sa and Sb from the received light signals output from the light receiving units 441 to 444, and the original signals from the modulated light signals Sa and Sb. The demodulating circuit unit 520 for restoring fa and fb, and the arithmetic processing unit 530 for calculating the displacement of the contact unit 220 based on the signal demodulated by the demodulating circuit unit 520 are provided.

Four band-pass filter units 510 are provided according to the four light receiving units 441 to 444. Each band-pass filter unit 510 includes a band-pass filter 511A having a center frequency of fa and a band-pass having a center frequency of fb. Two band pass filters, a filter 511B, are provided.
Similarly, four demodulation circuit units 520 are provided according to the four bandpass filter units 510, and each demodulation circuit unit 520 includes a demodulation circuit 521A that demodulates the original signal fa from the modulated light Sa, and a modulated light Sb. And a demodulating circuit 521B for demodulating the original signal fb.
Examples of the demodulation circuit include a peak hold circuit and a smoothing circuit.

With these four demodulation circuit units 520, four sets of signals composed of combinations of fa and fb are obtained.
The arithmetic processing unit 530 calculates the displacement of the contact unit 220 based on the four signal sets. That is, the arithmetic processing unit 530 obtains the shift amounts of the two light beams on the optical sensor 440 from the four signal sets, and calculates the displacement amount of the contact unit 220 from the displacement amounts of the two light beams.
A calculation example in the arithmetic processing unit 530 will be described later.

Here, the band-pass filter unit 510 and the demodulation circuit unit 520 constitute separation means for separating each modulated light signal from the received light signal.
Also, a shift amount calculating means for calculating the shift amount of the incident position where each modulated light enters the optical sensor by the arithmetic processing unit 530, and a probe displacement for calculating the displacement of the probe based on the shift amount of each modulated light And a calculation unit.

An operation when the probe 200 is displaced in the contact probe 100 having such a configuration will be described.
First, with reference to FIG. 6, the operation when the measuring element 200 is displaced in the + z direction will be described.

FIG. 6 is a diagram illustrating a state in which the contact portion 220 is displaced in the + Z direction.
When stress acts on the contact portion 220 from the −z direction to the + Z direction, the measuring element 200 is pushed up in the + Z direction. Then, the support plate 320 is displaced up and down in the notch of the support plate 320, and the displacement of the measuring element 200 in the + Z direction is allowed. When the center of the support plate 320 is displaced in the + Z direction together with the measuring element 200, the reflection mirror 410 is displaced in the + Z direction.

  Lights Sa and Sb emitted from the respective light sources 421A and 421 are incident on the reflection mirror 410 and then reflected by the reflection mirror 410. The reflection position is displaced in the + Z direction by the displacement of the reflection mirror 410 in the + Z direction. . Then, in the light reflected by the reflection mirror 410, the light Sa from the light source 421A is shifted to the −X side and the light Sb from the light source 421B is to the + X side than when the measuring element 200 is located at the reference position. shift. At this time, the light beam received by the optical sensor 440 is shown in FIG.

Next, the case where the contact part 220 is displaced in the X direction will be described with reference to FIGS.
FIG. 8 is a diagram illustrating a state in which the contact portion 220 is displaced (swinged) in the + X direction.
When stress acts on the contact portion 220 from the −X direction to the + X direction, the measuring element 200 swings in the + X direction. At this time, when the support plate 320 is cut, the support plate 320 is displaced upward in the + X direction, and is displaced downward in the −X direction so that the support plate 320 is elastically deformed, so that the displacement of the probe 200 in the X direction is allowed. Is done. Then, with the elastic deformation of the support plate 320, the reflection mirror 410 is inclined and the reflection surface 411 is inclined toward the −X direction side.

  The light emitted from the light sources 421A and 421B is incident on the reflection mirror 410 and then reflected by the reflection mirror 410. The reflection direction of the light is in the −X direction due to the inclination of the reflection mirror 410 in the −X direction. Displace. Then, the reflected light from the reflection mirror 410 is shifted to the −X side on the optical sensor 440 than when the measuring element 200 is positioned at the reference position (see FIG. 9).

Next, the case where the contact part 220 is displaced in the Y direction will be described with reference to FIGS.
FIG. 10 is a diagram illustrating a state in which the contact portion 220 is displaced in the + Y direction.
When stress is applied to the contact portion 220 from the −Y direction to the + Y direction, the probe 200 swings in the + Y direction.
At this time, when the support plate 320 is cut, the support plate 320 is displaced upward in the + Y direction, and is displaced downward in the −Y direction so that the support plate 320 is elastically deformed, so that the displacement of the probe 200 in the + Y direction is allowed. Is done. Then, with the elastic deformation of the support plate 320, the reflection mirror 410 is inclined and the reflection surface 411 is inclined toward the −Y direction.

  The light emitted from the light sources 421A and 421B is incident on the reflection mirror 410 and then reflected by the reflection mirror 410. The reflection direction of the light is in the −Y direction due to the inclination of the reflection mirror 410 in the −Y direction. Displace. Then, the reflected light from the reflection mirror 410 is shifted to the −Y side on the optical sensor 440 than when the measuring element 200 is located at the reference position (see FIG. 11).

Next, a case where stress is applied to the contact portion 220 from an arbitrary direction and the contact portion 220 is displaced in an arbitrary direction three-dimensionally will be considered.
When the contact portion 220 is displaced three-dimensionally, the support plate 320 is elastically deformed so as to allow the displacement of the probe 200, and the reflection mirror 410 is moved up and down and tilted along with the elastic deformation of the support plate 320. Then, the light Sa and Sb emitted from the light sources 421A and B are reflected by the reflection mirror 410, and the incident points of the light Sa and Sb on the optical sensor 440 are displaced.
At this time, the following expressions hold for the displacement (ΔXa, ΔYa) of the light Sa and the displacement (ΔXb, ΔYb) of the light Sb.

Here, the shift amount of the light Sa on the optical sensor 440 is (ΔXa, ΔYa), and the shift amount of the light Sb is (ΔXb, ΔYb).
Further, the incident angle of light from the light sources 421A and 421B to the reflection mirror 410 is defined as θ.
In the reference state (the state in which the contact portion 220 is not displaced), the distance from the stylus 210 to the light reflection position on the reflection mirror is La, and the vertical distance from the optical sensor 440 to the reflection mirror 410 is L.
The displacement of the reflection mirror 410 in the Z direction is dz.
The rotation angle around the x axis of the reflection mirror 410 (or contact portion 220) is θx, and the rotation angle around the y axis of the reflection mirror 410 (or contact portion 220) is θy.

  When the length of the stylus 210 is Ls, the following relationship is established between the coordinates (x, y, z) of the contact portion 220 and the posture and position (θy, θx, dz) of the reflection mirror 410. .

  The above formula is summarized as follows.

  The displacement amount (x, y, z) of the contact portion 220 can be obtained by the simultaneous equations of (Expression 8) to (Expression 11).

  According to 1st Embodiment provided with such a structure, there can exist the following effects.

(1) By using light from each of the light sources 421A and 421B as modulated light, even if all the modulated waves are received by one optical sensor 440, the signal of each modulated wave can be separated from the received light signal. Therefore, only one optical sensor 440 that receives light is used, and since a plurality of optical sensors 440 are not used as in the prior art, it is not necessary to calibrate the plurality of optical sensors 440, thereby greatly simplifying the measurement effort. be able to. Furthermore, since the number of parts can be reduced by using a single optical sensor 440, the contact probe 100 can be simplified and the contact probe 100 can be downsized.

(2) By using light from the light sources 421A and 421B as modulated light, even when disturbance noise is superimposed on the received light signal due to vibration or electrical noise applied to the contact probe 100, separation means (with a bandpass filter unit 510 and The influence of disturbance noise can be eliminated at the stage where the demodulated circuit portion 520) separates each modulated light signal from the received light signal. In particular, if the detection resolution is improved, there is a risk of being affected by disturbance noise. However, according to the first embodiment, the disturbance noise can be eliminated, so that the detection resolution can be improved and the accuracy can be improved. Can be improved.

(3) Since the optical sensor 440 is divided into four light receiving portions 441 to 444 by a cross-shaped dividing line 445 and the dividing line 445 is made to correspond to the x-axis and the y-axis, the light-receiving signals output from the four divided areas The shift amount of the incident position of the light can be easily obtained in the two-dimensional orthogonal coordinate system based on the change of.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the second embodiment is the same as that of the first embodiment, except that the second embodiment has three light sources 421A, 421B, and 421C, and the reflection mirror 460 is a triangular pyramid. Has characteristics.
In FIG. 12, the irradiation optical system includes three light sources 421A, 421B, and 421C.
The three light sources 421A, 421B, and 421C are arranged at intervals of 60 ° around the optical sensor 440. Each light source 421A, 421B, 421C emits light substantially parallel to the central axis A. Note that the light from each of the light sources 421A, 421B, and 421C is the same as that of the first embodiment in that the light is subjected to different modulation.

  The reflection mirror 460 has a triangular pyramid shape, and each reflection surface 461A, 461B, 461C faces the direction of each light source 421A, 421B, 421C. Triangular prisms 470A, 470B, and 470C are disposed between the light sources 421A, 421B, and 421C and the reflection mirror 460, and light from the light sources 421A, 421B, and 421C is reflected by the triangular prisms 470A, 470B, and 470C. To be incident on the reflection mirror 460.

  In the reference state where the displacement of the contact part 220 is zero, the light from each of the light sources 421A, 421B, 421C is adjusted so as to be incident on the center of the optical sensor 440 after being reflected by the reflection mirror 460. Yes. The optical sensor 440 is divided into four light receiving units 441 to 444, and the points where the light receiving signals are output from the respective light receiving units 441 to 444 are the same as in the first embodiment.

  Although not described in detail in FIG. 12 (FIG. 12), since there are three light sources 421A, 421B, and 421C and three modulated lights received by the optical sensor 440, each bandpass filter of the signal processing unit 500 It goes without saying that each section has three band-pass filters corresponding to each modulation wave, and each demodulation circuit section has three demodulation circuits.

  In such a configuration, the modulated light emitted from each of the light sources 421A, 421B, and 421C is incident on the reflection mirror 460 via the triangular prisms 470A, 470B, and 470C. Then, each modulated light reflected by the reflection mirror 460 enters the optical sensor 440. At this time, since the reflection mirror 460 is displaced according to the displacement of the measuring element 200, the reflection direction of the light by the reflection mirror 460 is changed, and the incident position of the light to the optical sensor 440 is shifted.

  Here, when the contact part 220 changes in the Z direction, the X direction, and the Y direction, the reflection mirror 460 is also displaced in the ΔZ direction, or tilted in the X direction and the Y direction to change the light reflection direction. Is the same as in the first embodiment. Furthermore, in the second embodiment, the reflecting mirror 460 has a triangular pyramid shape, and the reflecting surfaces 461A, 461B, and 461C are inclined with respect to the central axis A. Even when rotated around the center, the position where the modulated light from each of the light sources 421A, 421B, 421C enters the optical sensor 440 is shifted.

Further, since the reflection mirror 460 is a surface inclined with respect to the central axis A, each modulated light is incident on the optical sensor 440 even when the reflection mirror 460 is displaced two-dimensionally in the X direction or the Y direction. The position shifts. Therefore, not only when the reflection mirror 460 is tilted or displaced in the Z direction, but also when the reflection mirror 460 is two-dimensionally displaced (displacement in the X direction and Y direction) or rotated around the central axis, The incident position of light shifts.
That is, the incident position of light on the optical sensor 440 changes according to the displacement of the measuring element 200 with six degrees of freedom.

When light enters the optical sensor 440, a light reception signal is output from each of the light receiving units 441 to 444.
The signal processing unit 500 separates each modulated light signal from the received light signal, and calculates the shift amount of each modulated light. Then, the three-dimensional displacement amount of the contact portion 220 is obtained by combining the shift amounts of the respective modulated waves and establishing simultaneous equations relating to the displacement amounts (x, y, z, θx, θy, θr) of the contact portion 220. .

  When the origin of the orthogonal coordinate system is taken at the base end 210A of the stylus 210, θx is the swing angle of the stylus 210 when the contact portion 220 is displaced in the X direction with the x axis as the swing center. θy is the swing angle of the stylus 210 when the contact portion 220 is displaced in the Y direction with the y axis as the swing center, and θr is the rotation angle of the stylus 210 with the z axis as the center.

According to such 2nd Embodiment, in addition to the effect of the said 1st Embodiment, there can exist the following effect.
Since the reflection mirror 460 is a triangular pyramid having inclined reflection surfaces 461A, 461B, and 461C, the light reflection direction also changes depending on the rotation or two-dimensional displacement of the reflection mirror 460. Therefore, the 6-degree-of-freedom displacement of the probe 200 can be obtained, and the three-dimensional displacement of the contact portion 220 can be obtained.

(Modification 1)
Next, Modification 1 of the present invention will be described with reference to FIG.
The basic configuration of Modification 1 is the same as that of the second embodiment, but is characterized in that a condenser lens 480 is provided between the reflection mirror 460 and the optical sensor 440. Then, each light is imaged on the optical sensor 440 by the condenser lens 480 and is incident on the optical sensor 440 in a spot shape, whereby the detection resolution of the light incident position by the optical sensor 440 can be improved.
In particular, even when an LED or the like having a low directivity is used as a light source, light is imaged by the condenser lens 480, so that the detection resolution of the light incident position by the optical sensor 440 can be improved.

(Modification 2)
In the above-described embodiment, the light sources 421A and 421B of the illumination optical system 420 have been described as emitting the modulated lights Sa and Sb that are modulated differently.
Then, the modulated lights Sa and Sb from the respective light sources 421A and 421B are received by the optical sensor 440, and the modulated lights Sa and Sb are respectively separated and extracted by the signal processing unit 500 from the received light signal output from the optical sensor 440. .
Here, as a modulation pattern of the light emitted from each of the light sources 421A and 421B, as shown in FIG. 14, for example, the phases of each other are shifted by 180 degrees while being amplitude-modulated in a sine wave form.
Then, in detecting (holding) the light reception signal from the optical sensor in the signal processing unit 500, it is only necessary to detect the other signal level when one signal level becomes zero.
For example, in FIG. 14, by detecting signals at timings T ₁ , T ₂ , T ₃ ..., The modulated lights Sa and Sb can be detected separately.

  Further, as shown in FIG. 15, the modulated light Sa and Sb may be pulsed light, and the phases of each other may be shifted by a half cycle.

It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
Of course, the number of light sources is not two or three but may be more.
The light source may be an LED or a laser light source.
The optical element is described as an example of a reflection mirror, but may be a prism that refracts light.

  As a configuration for improving the detection sensitivity with respect to the displacement of the contact portion, the distance from the center to the cut line in the support plate may be shortened so that the tilt of the reflection mirror is increased even if the probe is slightly swung. . Alternatively, the lever ratio may be increased by increasing the distance from the reflection mirror to the optical sensor. Or you may enlarge the incident angle of the light from a light source to a reflective mirror.

  The displacement sensor may be used as a touch probe, for example, or may be used as a scanning probe.

  The present invention can be used for a displacement sensor and a shape measuring apparatus.

FIG. 3 is a perspective view illustrating the inside of the contact probe 100 in order to show the entire configuration of the contact probe 100 in the first embodiment. FIG. 3 is a cross-sectional view of the contact probe 100 cut in the vertical direction in the first embodiment. The top view of support plate 320 in a 1st embodiment. The figure which looked at the optical sensor 440 from the light-receiving surface side in 1st Embodiment. The figure which shows the structure of a signal processing part in 1st Embodiment. The figure which shows the state which the contact part 220 displaced to + Z direction in 1st Embodiment. The figure which shows the light beam received with an optical sensor, when a contact part displaces to a Z direction in 1st Embodiment. The figure which shows the state which the contact part 220 displaced to the + X direction (swing | rock) in 1st Embodiment. The figure which shows the light beam received with an optical sensor, when a contact part displaces (swings) in the X direction in 1st Embodiment. The figure which shows the state which the contact part 220 displaced to + Y direction in 1st Embodiment. The figure which shows the light beam received with an optical sensor, when a contact part displaces (swings) in the Y direction in 1st Embodiment. The figure which shows the whole structure of the contact probe 100 in 2nd Embodiment. The figure which shows the structure of the modification 1. FIG. The figure which shows the modulated light emitted from a light source in the modification 2. The figure which shows the modulated light emitted from a light source in the modification 2. The figure which shows the structure of the shape measuring apparatus using the conventional contact probe. The figure which shows a contact probe as a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Shape measuring apparatus, 11 ... Contact probe, 12 ... Drive mechanism, 13 ... Stylus, 14 ... Contact part, 15 ... Sensor main part, 100 ... Contact probe, 200 ... Measuring element, 210 ... Stylus, 210A ... Stylus base end , 220 ... contact part, 300 ... sensor body part, 310 ... housing part, 311 ... storage space, 312 ... sheet material, 320 ... support plate, 321 ... cut line, 322 ... arc part, 323 ... straight part, 324 ... reinforcement Plate: 400: Displacement detecting means, 410: Reflecting mirror, 411: Reflecting surface, 420: Irradiation optical system, 421A, 421B ... Light source, 430 ... Light receiving optical system, 440 ... Optical sensor, 441 ... First light receiving unit, 442 ... Second light receiving unit, 443 ... third light receiving unit, 444 ... fourth light receiving unit, 445 ... dividing line, 460 ... reflection mirror, 500 ... signal processing unit, 510 ... van Pass filter unit, 511A ... bandpass filter, 511B ... bandpass filter, 520 ... demodulation circuit section, 521A ... demodulation circuit, 521B ... demodulation circuit, 530 ... arithmetic processing unit.

Claims (6)

A measuring element;
A sensor main body for supporting the measuring element in a displaceable manner and detecting a displacement amount and a displacement direction of the measuring element,
The sensor body is
Support means for supporting the measuring element in a displaceable manner;
Two or more light sources,
An optical sensor that receives light and outputs a light reception signal corresponding to the amount of light received by photoelectric conversion;
A light shift means for shifting the incident position of the light emitted from each light source to the optical sensor in accordance with the displacement of the probe;
A signal processing unit that calculates a displacement amount and a displacement direction of the probe based on the light reception signal, and
The two or more light sources emit modulated light, each of which is modulated differently, toward the light shift means,
The optical sensor is divided into a plurality of light receiving parts by a plurality of dividing lines, and outputs a light reception signal corresponding to the amount of light received for each light receiving part,
The signal processing unit
Separating means for separating each modulated light signal from the light receiving signal output from the optical sensor;
Shift amount calculating means for calculating the shift amount of the incident position where each modulated light is incident on the optical sensor based on the signal of each modulated light separated by the separating means;
A displacement measuring unit for calculating displacement of the measuring element based on a shift amount of each modulated light. The displacement sensor according to claim 1,
A displacement sensor characterized in that a method for modulating light from the light source is any one of amplitude modulation, phase modulation and frequency modulation. The displacement sensor according to claim 1 or 2 ,
The light shifting means is
A displacement sensor, wherein the displacement sensor is an optical element that is displaced according to the displacement of the probe and reflects or refracts light from the light source. The displacement sensor according to claim 3 ,
The displacement sensor, wherein the optical element is a reflection mirror that is attached to the measuring element via the support means and is displaced together with the measuring element to change a position and a reflection surface angle. The displacement sensor according to any one of claims 1 to 4 ,
The displacement means is a displacement sensor characterized in that the support means is an elastic plate and has a plurality of cut lines with point symmetry with respect to the center of the plate, and supports the measuring element at the center of the plate. The displacement sensor according to any one of claims 1 to 5 ,
A drive mechanism for moving the displacement sensor relative to the object to be measured to bring the displacement sensor into contact with the object to be measured;
A drive sensor for detecting a relative displacement amount between the displacement sensor and the object to be measured by the drive mechanism;
Analyzing means for analyzing the shape of the object to be measured based on detection values obtained by the displacement sensor and the drive sensor. A shape measuring apparatus comprising:

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