JPH0540821A - 3-dimensional measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a three-dimensional measuring device capable of measuring the dimensions of a target object in three axial directions with high accuracy without being affected by the target object and having a wide measuring range. [Structure] An image processing CCD camera 5 and a laser length measuring device 6 are fixed to a Z stage 4. The laser length-measuring device 6 uses a confocal reflection type optical system and can obtain a detection signal only when the object 3 is at a fixed position (object-side focal position), and further, its detection range. Is narrow. CC for image processing
The D camera 5 measures the X-axis direction and Y-axis direction dimensions (or the plane shape in the XY plane) of the object 3. The laser length measuring device 6 moves the Z stage 4 while moving the object 3
The surface of the object and the focal point on the object side are monitored to detect the dimension of the object 3 in the Z-axis direction from the amount of movement of the Z stage 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional measuring device. More specifically, the present invention relates to a non-contact type three-dimensional measuring device that measures the three-dimensional dimensions of an object.

[0002]

2. Description of the Related Art The three-dimensional dimension of an object (that is, the dimension in the axial direction of the device [hereinafter, referred to as the Z-axis direction]) and two directions perpendicular to the axial direction [hereinafter, the X-axis direction and the Y-axis direction]. As a three-dimensional measuring device for measuring the dimension []], there is one using an image processing camera. Z of this image processing camera
The measurement accuracy in the axial direction (optical axis direction of the image processing camera) is determined by the accuracy of the autofocus function used in the image processing camera. However, the length measurement accuracy of the autofocus is at most several 10 μm, and the length measurement accuracy in the Z-axis direction is worse than in the X-axis direction and the Y-axis direction.

Therefore, conventionally, a Z-axis length measuring dedicated machine is added to the image processing camera to improve the Z-axis length measuring accuracy. As this Z-axis length measurement dedicated machine, conventionally, a Z-axis length measurement dedicated machine using the optical cutting method and a Z-axis length measurement dedicated machine using the principle of triangulation have been used.

FIG. 4 is a schematic view of a Z-axis length measuring dedicated machine 51 utilizing the optical cutting method. This is because the slit light irradiating unit 52 irradiates the object 54 with the slit light 53 obliquely (FIG. 5A), and the light pattern 55 on the surface of the object 54 (the surface in the cross section parallel to the slit light 53). Corresponding to the shape of the side edge) through the objective lens 56 to the CCD
(Charge-coupled device) Captured by the camera 57, the light pattern 55 is displayed on the monitor 58 as shown in FIG. 5B, and the Z of the object 54 is detected from the light pattern 55 displayed on the monitor 58.
This is to know the dimension (change in height) in the axial direction.

However, in the light cutting method, since the slit light is radiated onto the object obliquely, it is easily affected by the shape of the object to be measured. For example, if there is a large protruding portion on the slit light irradiation side of the object. However, there is a drawback that a light pattern changes due to a shadow. Moreover, since the Z-axis length measurement is performed from the light pattern representing the oblique cross section, the measurement accuracy is low.

FIG. 6 (a) shows Z using the principle of triangulation.
It is a front view of the machine for exclusive use of axis length measurement 61. This is because the object 62 is irradiated with the light 62 emitted from the dedicated Z-axis length measuring machine 61 and the reflected light from the object 63 is detected to detect the object 6.
The length of 3 in the Z-axis direction is detected. Figure 6 (b)
Is a schematic diagram showing the basic configuration of the Z-axis length measuring machine 61, in which the light 62 emitted from the semiconductor laser element 64 is
The light is condensed by the condensing lens 65 and is irradiated onto the object 63. Depending on the distance to the object 63, the position detection element (P
Since the light receiving position of SD) 66 changes, the position detecting element 6
The size of the object 63 in the Z-axis direction can be detected from the change in the output of No. 6.

However, Z utilizing the principle of triangulation
Even with a dedicated axis length measuring machine, there was the problem that the measurement range was narrow.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and an object of the present invention is to measure with high accuracy without being influenced by an object to be measured. It is possible to provide a three-dimensional measuring device that is capable of performing a wide measurement range.

[0009]

A three-dimensional measuring apparatus according to the present invention comprises a measuring apparatus body utilizing image processing, a laser length measuring instrument using a confocal reflection type optical system, and an object side of the laser length measuring instrument. And a means for scanning the focal position in the length measuring direction of the laser length measuring device.

[0010]

The three-dimensional measuring apparatus of the present invention uses the laser length measuring device of the confocal reflection type optical system as a Z-axis length measuring dedicated device. The confocal reflection type optical system is characterized in that an image is obtained by focusing only on a certain surface (focal position on the object side), and the focusing range is very narrow. Therefore, by adding the laser length measuring device to the main body of the three-dimensional measuring device utilizing image processing, the planar shape of the object and the dimension in the vertical direction can be detected with high accuracy. In particular, the Z-axis length measuring accuracy is improved as compared with the three-dimensional measuring device using the Z-axis length measuring dedicated machine using triangulation.

Further, since the laser beam is applied vertically to the object, it is not affected by the shape of the object to be measured, unlike the three-dimensional measuring apparatus using the light cutting method.

Further, since the means for scanning the object side focal position of the laser length measuring device is provided, the measuring range is widened, and the dimension in the Z-axis direction can be measured over a wide range.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of a three-dimensional measuring apparatus 1 according to the present invention. Reference numeral 2 is an XY stage that moves the object 3 on its upper surface and moves in parallel to the XY plane, and 4 is a Z stage that moves in the Z-axis direction. The Z stage 4 has a CC for image processing.
The D camera 5 and the laser length measuring device 6 are fixed in parallel with each other with an offset amount δ. The signal from the image processing CCD camera 5 and the signal from the laser length-measuring device 6 are input to the image processing calculation unit 7, and the image processing CCD camera 5 and the image processing calculation unit 7 form a measuring device body. ing. Further, the laser length measuring device 6 is a Z-axis length measuring dedicated device.

The laser length measuring device 6 uses a confocal reflection type optical system, and FIG. 2 shows a principle diagram of the confocal reflection type optical system. The light α emitted from the point light source 8 is reflected by the beam splitter 9, passes through the objective lens 10, and is condensed on the surface of the object 3 at the object-side focal position. On the other hand, the light α reflected on the surface of the object 3 passes through the objective lens 10 and the beam splitter 9, is condensed by the pinhole 11 provided at the image-side focal position, and then opposes the pinhole 11. An image is formed on a detector 12 such as a CCD image sensor which is arranged in a vertical direction. However, in such a confocal reflection type optical system, when the object 3 is at the object-side focal position,
Although the detection intensity of the detector 12 is extremely high, the detection intensity of the detector 12 sharply decreases when the object 3 is slightly displaced from the object-side focal position. Therefore, if a confocal reflection type optical system is used for the laser length measuring device 6, a detection signal can be obtained only when the object 3 is at a fixed position (object-side focal position), and the detection position is High precision Z because it is narrow
It can be a dedicated axis length measuring machine.

Since a laser microscope is used as an optical device utilizing the confocal reflection type optical system as described above, the laser length measuring device of the present invention can have the same structure as the laser microscope. FIG. 3 shows a schematic configuration of an example of the laser length measuring device.
That is, the laser beam β emitted from the laser tube 13 such as He-Ne and having passed through the beam expander 14 has its optical path changed by about 45 degrees by the mirror 15, and the AO (Acoustic Opt)
ical) element 16. The AO element 16 can bend the path of the laser light β by an angle proportional to the applied voltage. Further, the laser light β, after passing through the AO element 16, is reflected by the beam splitter 9, further reflected by the vibrating mirror 18 and the mirror 19, condensed by the objective lens 10 and condensed on the surface of the object 3. It The laser beam β reflected on the surface of the object 3 returns to the original direction through the objective lens 10 again, is reflected by the mirror 19 and the vibrating mirror 18, passes through the beam splitter 9, and is a pinhole (in FIG. After passing through (not shown), an image is formed on the detector 12. At this time, the laser light β is, for example, 1 by the AO element 16.
The surface of the object 3 is scanned in the X direction at a frequency of 5.73 kHz, and the vibrating mirror head 17 causes the vibrating mirror 18 to move.
Is rotated at a frequency of, for example, 60 Hz, so that the surface of the object 3 is scanned in the orthogonal Y direction. In this way, the laser beam β is made to scan the surface of the object 3 in a plane shape, and the detector 1
If the detection is made in 2, the detection signal can be obtained only when the object 3 matches the object-side focal position.

Since the laser length measuring device 6 of the present invention does not necessarily require the scanning system, the AO element 16 and the vibrating mirror 18 in the configuration of FIG. 3 may be omitted.

However, at the time of measurement, the object 3 is set on the XY stage 2, and the XY stage 2 is moved to bring the object 3 directly under the image processing CCD camera 5. Then, the object 3 is captured by the image processing CCD camera 5, and the dimensions of the object 3 in the X-axis direction and the Y-axis direction (or the planar shape in the XY plane) and the approximate Z-axis direction dimension can be measured. it can. Then, the XY stage 2 is moved by the offset amount δ, and the point on the optical axis of the image processing CCD camera 5 on the upper surface of the object 3 is made to coincide with the optical axis of the laser length measuring device 6. Subsequently, the Z stage 4 is continuously moved in the Z-axis direction while the object 3 is detected by the laser length measuring device 6, and the output of the laser length measuring device 6 is monitored by the image processing calculation unit 7. At this time, the output of the laser length-measuring device 6 has a maximum value when the surface of the object 3 coincides with the object-side focal point of the laser length-measuring device 6. It is possible to know the Z-axis direction dimension. Moreover, since the maximum value of the output shows a sharp peak, it is possible to obtain highly accurate Z-axis length measurement accuracy.

As described above, the laser length-measuring device 6 can obtain an output only at the focal position on the object side, so that the Z-axis with high precision can be obtained.
Axial length measurement accuracy can be obtained, and a wide measurement range can be obtained by moving the laser length measuring device 6 in the Z axis direction by the Z stage 4. Therefore, the three-dimensional shape of the target object 3 is highly accurately measured by measuring the plane shape of the target object 3 by the measuring device main body using image processing and measuring the height of the target object 3 by the laser length measuring device 6. It can be measured.

Of course, the measuring instrument main body may be for two-dimensional measurement without the function of measuring the dimension in the Z-axis direction.

[0020]

According to the three-dimensional measuring apparatus of the present invention, the plane shape of the object can be measured with high accuracy by the main body of the three-dimensional measuring apparatus using image processing, and the object can be measured by the laser length measuring device. The height of an object can be detected with high accuracy. Therefore, the dimension in the plane of the object (planar shape) and the dimension in the vertical direction (height of the object) can be detected with high accuracy.

Further, there is an advantage that the measuring range is wide and it is hardly affected by the shape of the object to be measured.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a three-dimensional measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a principle diagram of a confocal reflection type optical system.

FIG. 3 is a schematic perspective view showing the configuration of the above laser length measuring device.

FIG. 4 is a front view showing a dedicated Z-axis length measuring machine in a conventional three-dimensional measuring apparatus.

FIG. 5A is a perspective view showing a state in which a slit light is applied to an object, and FIG. 5B is a view showing a light pattern displayed on a monitor.

FIG. 6A is a front view showing a Z-axis length measuring dedicated machine in another conventional three-dimensional measuring apparatus, and FIG. 6B is a schematic view showing the internal structure thereof.

[Explanation of reference numerals] 3 object 4 Z stage 5 CCD camera for image processing 6 laser length measuring device 7 image processing operation unit

Continued Front Page (72) Inventor Kitanaka Orthodox, 10 Odoroncho, Hanazono, Ukyo-ku, Kyoto City Omron Corporation

Claims (1)

[Claims] 1. A measuring device body using image processing, a laser length measuring device using a confocal reflection type optical system, and an object-side focal position of the laser length measuring device scanning in a length measuring direction of the laser length measuring device. A three-dimensional measuring device including a means for causing the measurement.