JPH10132527A - Three-dimensional form measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely measure a matter to be measured having a narrow or complicated form by providing a light shielding mask having a slit laid along the plane determined by both optical axes of emitted and reflected laser beams on a light receiving part side. SOLUTION: A light position detecting element 4 is mounted on the vertical wall part 12a of a bracket 12 together with a circuit board 11, and a light shielding mask 13 is stuck to the glass plate surface on a light receiving part side. The light shielding mask 13 is formed of a laser beam shielding film, which has a slit 14 formed along the longitudinal direction in a position corresponding to the light position detecting element 4 in the center. Only a primary reflected laser beam LR reflected by the emitted laser beam LT irradiated part of a matter to be measured is passed through the slit 14 of the light shielding mask 13, and received by the light position detecting element 4. The secondary reflected light reflected by other than the emitted laser beam LT irradiated part is shifted from the slit 14 since the reflecting direction is differed from the primary reflected laser beam LR, and prevented from being passed by the shielding mask 13. Thus, the only the primary reflected laser beam LR necessary for measurement is received, whereby a highly precise measurement can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional shape measuring device used for measuring the shape of an object having a three-dimensional shape in a non-contact state by using a laser beam. The present invention relates to a three-dimensional shape measuring apparatus suitable for measuring the shape of an object to be measured such as a tooth model for manufacturing.

[0002]

2. Description of the Related Art FIG. 6 is a view showing a tooth model which is an example of an object to be measured having a three-dimensional shape. The tooth model M is formed on a base D by forming an abutment tooth A and adjacent teeth B on both sides thereof.
C is provided. In order to measure the shape of such a tooth model M, for example, a three-dimensional shape measuring device as shown in FIG. 7 is used.

[0003] The three-dimensional shape measuring apparatus 100 is a tooth model M
A laser light source 101 that oscillates irradiation laser light LT toward the measurement point Pm, and a light position detection element (PSD) that receives the reflected laser light LR from the tooth model M via the optical lens 102 and detects the light receiving position thereof. Photo Positi
on Sensitive Device) 103, and measures the distance to the object M by triangulation.

That is, the light receiving position y of the light position detecting element 103, the light receiving surface end distance yo of the light position detecting element 103, the light receiving surface arrangement angle θ of the light position detecting element 103, and the light receiving surface disposing distance of the light position detecting element 103 From d2, the survey angle α (tan α) of the reflected laser light LR is obtained,
Further, the distance L from the sensor reference point Ps to the measurement point Pm of the DUT is obtained from the survey angle α (tan α) and the distance d1 from the sensor reference point Ps to the center of the optical lens 102. Then, the three-dimensional shape of the tooth model M is specified by obtaining the distance L for the plurality of measurement points Pm.

[0005]

When the shape of the tooth model M is measured using the three-dimensional shape measuring apparatus 100 as described above, for example, the laser beam LT is applied to the abutment A of the tooth model M. When the light is irradiated, secondary reflection (indicated by LS in FIG. 6) occurs at the adjacent teeth B and the like near the irradiated portion, and the reflected laser light LR including the secondary reflected light is received by the light position detecting element 103. Measurement accuracy may be reduced.

On the other hand, in a three-dimensional shape measuring apparatus using a laser beam, as a means for preventing a decrease in measurement accuracy due to a secondary reflected light, only a primary reflected light necessary for measurement is passed and a secondary reflected light is transmitted. In some cases, a light-shielding plate was provided to block the light.
Since the direction of reflection of the primary reflected light and the direction of the secondary reflected light are different from each other, this light shielding plate is arranged as close to the surface of the DUT as possible so that only the primary reflected light passes to the light position detecting element side.

Therefore, when measuring the shape of a tooth model using a three-dimensional shape measuring apparatus, the use of the above-mentioned light-shielding plate was examined. However, since the tooth model has a narrow measuring portion and the shape is complicated, it is particularly required. There is a problem that it is difficult to arrange a light shielding plate in the vicinity of a narrow measurement part, and it is difficult to set the position of the light shielding plate because the reflection direction of the secondary reflected light differs depending on the measurement position. As a result, other means other than the light shielding plate have been demanded.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances. Particularly, even if the object to be measured has a narrow measuring portion and has a complicated shape, the shape of the object to be measured can be improved. It is an object of the present invention to provide a three-dimensional shape measuring device capable of measuring the height of a three-dimensional shape with high accuracy.

[0009]

According to a first aspect of the present invention, there is provided a three-dimensional shape measuring apparatus, comprising: a laser light source for irradiating a three-dimensional object to be measured with an irradiation laser beam; An optical position detecting element for receiving the reflected laser light and detecting the light receiving position thereof is provided, and the optical axis of the irradiation laser light and the optical axis of the reflected laser light when measuring the reference plane are provided on the light receiving portion side of the optical position detecting element. A light-shielding mask having a slit along a plane determined by the two axes of the light-shielding mask is a film, and the light-shielding mask is attached to the light-receiving portion side of the optical position detecting element. According to a third aspect of the present invention, the slit of the light-shielding mask has a width substantially the same as the diameter of the laser beam spot. Between the Tsu bets, it has a structure in which a fine adjustment mechanism for both the spacing and the tilt of the bracket to the variable, and a means for solving the problems of the above configuration.

[0010]

In the three-dimensional shape measuring apparatus according to the first aspect of the present invention, the optical axis of the irradiation laser light and the optical axis of the reflected laser light when measuring the reference plane are provided on the light receiving portion side of the optical position detecting element. Since the light-shielding mask having a slit along a plane determined by the two axes is provided, only the primary reflected laser light reflected at the irradiated portion of the object to be irradiated by the irradiated laser light passes through the slit of the light-shielded mask, The primary reflected laser light is received by the light position detecting element. In addition, the secondary reflected light reflected at a position other than the irradiated portion of the irradiation laser light has a different reflection direction from the primary reflected laser light, so that the light comes off the slit of the light shielding mask and is directed to the light position detecting element side by the light shielding mask. Passage is blocked.

In the three-dimensional shape measuring apparatus according to the second aspect of the present invention, since the light-shielding mask made of a film is attached to the light-receiving portion side of the optical position detecting element, a gap between the light-shielding mask and the light-receiving portion is reduced. It becomes extremely small, and more reliably prevents reflected light other than the primary reflected laser light from entering the optical position detecting element side.

In the three-dimensional shape measuring apparatus according to the third aspect of the present invention, since the slit of the light shielding mask has a width substantially equal to the diameter of the laser beam spot, only the primary reflected laser beam cuts the slit. The reflected light other than the primary reflected laser light is more reliably prevented from entering the optical position detecting element side.

In the three-dimensional shape measuring apparatus according to a fourth aspect of the present invention, the fine position adjustment mechanism provided between the fixed portion of the device and the bracket on which the light position detecting element is mounted is operated, whereby the light position detecting element is operated. The fixed portion of the apparatus is arranged such that the slit of the light-shielding mask provided at a position along the plane determined by the two axes of the optical axis of the irradiation laser light and the optical axis of the reflected laser light when measuring the reference plane. The distance between the bracket and the bracket and the inclination of the bracket are adjusted.

[0014]

According to the three-dimensional shape measuring apparatus according to the first aspect of the present invention, only the primary reflected laser light necessary for the measurement is passed through the slit of the light shielding mask, received by the light position detecting element, and blocked. Since the mask can prevent the secondary reflected light from entering the optical position detecting element, the measurement accuracy can be greatly improved, and it is necessary to dispose a light shielding plate or the like close to the object to be measured. Since the measurement is performed in a state completely separated from the object to be measured, even an object having a narrow measuring portion and a complicated shape such as a tooth model can be easily measured with high accuracy. It can be carried out. Furthermore, when irradiating the irradiation laser light on the inclined surface of the object to be measured,
Although the spot shape of the reflected laser light may be distorted, even in such a case, it is possible to receive light at almost the center position of the spot area, and to perform highly accurate measurement.

According to the three-dimensional shape measuring apparatus of the second aspect of the present invention, the same effect as in the first aspect can be obtained, and a light-shielding mask made of a film is provided on the light-receiving portion side of the light position detecting element. Since the light-shielding mask is attached, the light-shielding mask can be obtained at low cost, and the gap between the light-shielding mask and the light receiving portion is extremely small, so that only the primary reflected laser light can be received by the light position detecting element. With 2
It is possible to more reliably prevent the next reflected light from entering the light position detecting element side, which can contribute to further improvement in measurement accuracy.

According to the three-dimensional shape measuring apparatus of the third aspect of the present invention, the same effect as in the first and second aspects can be obtained, and the slit of the light shielding mask is substantially the same as the diameter of the laser beam spot. , The function of passing only the primary reflected laser light and blocking the passage of the secondary reflected light can be further enhanced.

According to the three-dimensional shape measuring apparatus according to the fourth aspect of the present invention, the same effects as in the first to third aspects can be obtained, and the slit of the light shielding mask together with the bracket is operated by operating the fine adjustment mechanism. Can be easily adjusted, so that the slit of the light-shielding mask is aligned with a plane determined by the two axes of the optical axis of the irradiation laser light and the optical axis of the reflected laser light when measuring the reference plane. Accurate measurement is made possible in accordance with the conditions along the line.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a three-dimensional shape measuring apparatus according to the present invention will be described below with reference to the drawings.

A three-dimensional shape measuring apparatus 1 shown in FIG. 1 includes a laser light source 3 for irradiating an irradiation laser beam LT to a three-dimensional object to be measured (not shown) in a case 2 and a reflection from the object to be measured. A light position detecting element 4 for receiving the laser light LR and detecting a light receiving position thereof is provided, and in addition, a light receiving lens (see reference numeral 102 in FIG. 7) for the reflected laser light LR is provided.

The case 2 is open on one side and accommodates a laser light source 3 in the center and an optical position detecting element 4 on both sides thereof. Has an irradiation window 5 for the irradiation laser light LT at the center, and a light reception window 6 for the reflection laser light LR on both sides thereof.
6. The light receiving windows 6, 6 on both sides are in a state of being inclined inward from each other corresponding to the reflection angle of the reflected laser light LR. A lid 8 is attached to an open portion of the case 2 with a plurality of screws 7.

The light position detecting element 4 is provided in the case 2 so as to face the light receiving window 6. The light position detecting element 4 has a band shape as shown in FIG. 4 and is mounted in a holder 10 provided with a protective glass plate 9 on the light receiving section side. The holder 10 is provided with terminals 10 a to 10 d electrically connected to the light position detecting element 4. These terminals 10a to 10d are connected to the circuit board 11 of the light position detecting element 4 shown in FIG. The circuit board 11 is provided with a connector 20 for a controller (not shown).

The light position detecting element 4 is mounted on the vertical wall 12a of the L-shaped bracket 12 together with the holder 10 and the circuit board 11, and a light shielding mask 13 is attached to the surface of the glass plate 9 on the light receiving side. It is installed in the case 2 by attaching a bracket 12 to the case bottom surface 2a which is a fixing portion of the device.

The light-shielding mask 13 is made of a film for blocking laser light, and a slit 14 along the longitudinal direction of the light position detecting element 4 is provided at a position corresponding to the light position detecting element 4 at the center. Is formed. The slit 14 has a width substantially equal to the diameter of the laser beam spot.

The bracket 12 is attached to the case bottom surface 2a by a fine adjustment mechanism that makes the distance between the two and the inclination of the bracket 12 variable. The fine adjustment mechanism is
The lower horizontal wall portion 12b of the bracket 12 includes a gap adjusting screw 15 located at the center and two tilt adjusting screws 16a and 16b provided on both sides thereof. The spacing adjusting screw 15 is threaded through the lower lateral wall portion 12b of the bracket 12 and abuts on the case bottom surface 2a. On the other hand, each of the tilt adjusting screws 16a and 16b is
, And is screwed into the case bottom surface 2a, and the degree of inclination of the bracket 12 is changed by changing the screwing amount between left and right.

As described above, the bracket 1 is attached to the case bottom surface 2a.
2, the light position detecting element 4 has the slit 14 of the light shielding mask 13 attached to the light receiving portion side.
Are arranged along a plane determined by two axes of the optical axis of the irradiation laser beam LT and the optical axis of the reflected laser beam LR when measuring the reference plane S shown in FIG. ing. That is, the fine adjustment mechanism described above results in the slit 1
4 to adjust the position, so that the slit 14 is in a state along a plane determined by the two optical axes.
The distance between the case bottom surface 2a and the bracket 12 and the inclination of the bracket 12 are adjusted. This fine adjustment can be easily performed while actually measuring the reference plane S and watching the output display from the circuit that converts the output current of the optical position detection element 4 into a voltage.

Next, the operation of the three-dimensional shape measuring apparatus 1 will be described.

FIG. 3 is a view showing a state in which a laser beam is irradiated on the object to be measured W. FIG. 3A shows two axes of an optical axis of the irradiation laser light LT and an optical axis of the reflected laser light LR. FIG. 3B is a diagram of a state in which a determined plane is viewed from a right angle direction, and FIG.
(D) is a view of the same plane viewed from a parallel direction.

First, as shown in FIGS. 3 (a) and 3 (b), if the light position detecting element 4 is not provided with a light-shielding mask, when the object to be measured W is irradiated with the irradiation laser light LT, the light is reflected at the irradiated part. The primary reflected laser light LR is received by the light receiving lens 1.
7, the light is detected by the light position detecting element 4, and secondary reflection is generated on the measured object W. The secondary reflected light LS is also received by the light position detecting element 4 via the light receiving lens 17.
As a result, the measurement accuracy decreases. At this time, since the secondary reflected light LS is reflected at a position other than the irradiated portion of the irradiation laser light LT on the workpiece W, the reflection direction is different from that of the primary reflected laser light LR. The light is received at a position different from the primary reflected laser light LR.

Therefore, in the three-dimensional shape measuring apparatus 1,
As shown in FIG. 3C, the optical axis of the irradiation laser beam LT and the optical axis of the reflected laser beam LR when the reference plane S is measured are determined on the light receiving portion side of the optical position detection element 4 by two axes. A light-shielding mask 13 having a slit 14 along a plane to be measured is provided, so that only the primary reflected laser light LR reflected at the irradiated portion of the object W to be irradiated with the irradiation laser light LT is transmitted to the slit 14 of the light-shielded mask 13. The primary reflected laser light LR is received by the light position detecting element 4. Further, since the secondary reflected light LS reflected at a position other than the irradiated part of the irradiation laser light LT has a different reflection direction from the primary reflected laser light LR, it comes off the slit 14 of the light shielding mask 13,
The light shielding mask 13 prevents passage to the light position detecting element 4 side. Therefore, in the three-dimensional shape measuring apparatus 1, accurate measurement is performed by receiving only the primary reflected laser beam LR required for measurement by the optical position detection element 4.

The distance to the object to be measured W is obtained by the triangulation method described with reference to FIG.
By measuring the distances at a plurality of locations, the shape of the DUT W is specified.

FIG. 3D shows a comparative example in which a light shielding mask 13 is provided on the front side of the light receiving lens 17. In this case, both the primary reflected laser light LR and the secondary reflected light LS pass through the slit 14 of the light shielding mask 13 and are received by the light position detecting element 4.

On the other hand, the three-dimensional shape measuring device 1
In this case, since the light shielding mask 13 is attached to the light receiving portion side of the light position detecting element 4, the gap between the light shielding mask 13 and the light receiving portion becomes extremely small.
Is approximately the same as the diameter of the laser beam spot, so that only the primary reflected laser light LR is received by the light position detecting element 4 and the secondary reflected light LS enters the light position detecting element 4 side. It is more reliably blocked.

As described above, in the three-dimensional shape measuring apparatus 1 of the above embodiment, it is not necessary to dispose a light shielding plate or the like close to the object W, and the measurement can be performed in a state where the object W is completely separated from the object W. Therefore, accurate measurement can be easily performed even on an object to be measured having a narrow measuring portion and a complicated shape, such as a tooth model shown in FIG.

In the three-dimensional shape measuring apparatus 1, since the light receiving surface of the light position detecting element 4 is linearly used with a width corresponding to the diameter of the laser beam spot by the slit 14, the light position detecting element 4 is used. There is an advantage that there is no influence of the lateral error due to the non-uniform resistance value distribution of the resistance layer.

FIG. 5 is a view showing another example of the fine adjustment mechanism. In this example, two adjustment screws 1 penetrating the lower horizontal wall portion 12b of the bracket 12 and screwing into the case bottom surface 2a are shown.
8a, 18b and an adjustment shim 19 interposed between the lower horizontal wall portion 12b and the case bottom surface 2a constitute a fine adjustment mechanism.

Even in the above-mentioned fine adjustment mechanism, the distance between the case bottom surface 2a and the bracket 12 and the bracket can be changed by changing the screwing amounts of the adjustment screws 18a and 18b and the interposition position or number of the adjustment shims 19. 12 is adjusted, and as a result, the slit 14 of the light shielding mask 13 in the light position detecting element 4 attached to the bracket 12 causes the optical axis of the irradiation laser beam LT and the reflected laser beam when the reference plane S is measured. The adjustment is performed so as to be in a state along a plane determined by two axes of the light LR and the optical axis of the light LR.

[Brief description of the drawings]

FIG. 1A is a perspective view illustrating an embodiment of a three-dimensional shape measuring apparatus according to the present invention, and FIG. 1B is a perspective view illustrating a bracket provided with a light position detecting element.

FIG. 2 is a cross-sectional view illustrating a fine adjustment mechanism of a bracket.

FIGS. 3A and 3B are diagrams illustrating a state in which an object to be measured is irradiated with an irradiation laser beam, and are explanatory diagrams (a) and (b) from two directions showing a case where there is no light shielding mask; FIG. 7C is an explanatory diagram showing a case where a light-shielding mask is provided on the side, and FIG. 7D is an explanatory diagram showing a case where a light-shielding mask is provided on the front side of a light receiving lens as a comparative example.

FIG. 4 is a front view (a) and a side view (b) illustrating a light position detecting element and a holder.

FIG. 5 is a sectional view illustrating another example of the fine adjustment mechanism of the bracket.

FIG. 6 is a perspective view illustrating a tooth model as an example of an object to be measured.

FIG. 7 is an explanatory view showing distance measurement by a conventional three-dimensional shape measuring apparatus and a triangulation method.

[Explanation of symbols]

 Reference Signs List 1 3D shape measuring device 2a Case bottom (fixed part of device) 3 Laser light source 4 Optical position detecting element 12 Bracket 13 Light shielding mask 14 Slit 15 Interval adjustment screw (fine adjustment mechanism) 16a 16b Tilt adjustment screw (fine adjustment mechanism) 18a 18b Adjustment screw (fine adjustment mechanism) 19 Adjustment shim (fine adjustment mechanism) LR Reflected laser light LT Irradiated laser light S Reference plane W DUT

Continued on front page (72) Inventor Toshihiko Matsuda 2 Nissan Motor Co., Ltd., Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa

Claims (4)

[Claims] 1. A laser light source for irradiating an irradiation laser beam toward a three-dimensional object to be measured, and a light position detecting element for receiving a reflected laser beam from the object to detect a light receiving position thereof, A light-shielding mask having a slit along a plane determined by two axes of the optical axis of the irradiation laser light and the optical axis of the reflected laser light when measuring the reference plane is provided on the light receiving portion side of the light position detecting element. A three-dimensional shape measuring device characterized by the following. 2. The three-dimensional shape measuring apparatus according to claim 1, wherein the light-shielding mask is a film, and the light-shielding mask is affixed to the light receiving portion side of the optical position detecting element. 3. The three-dimensional shape measuring apparatus according to claim 1, wherein the slit of the light shielding mask has a width substantially equal to the diameter of the laser beam spot. 4. A fine-adjustment mechanism for varying the distance between the two and the inclination of the bracket is provided between the fixed portion of the device and the bracket on which the optical position detecting element is mounted. The three-dimensional shape measuring device according to any one of the above.