JP2001324315A - Measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of performing accurate measurement by a measuring instrument for measuring the angle of inclination, flatness, surface roughness, etc., of an inspected surface by forming an image by reflected light from the inspected surface. SOLUTION: In this measuring instrument 1, reflected light from the inspected surface 71 is detected by a position detecting element 8 and the result of light reception is outputted as information converted into voltages in X and Y directions representing the centroidal position of the light. By assuming information outputted as voltages in the X and Y directions representing the centroidal position of a spot image, the centroidal position of the spot image can be accurately determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device used for measuring the inclination angle, flatness, surface roughness and the like of an object to be inspected.

[0002]

2. Description of the Related Art A measuring apparatus (autocollimator) used for measuring an inclination angle, flatness, surface roughness, and the like of a parallel flat plate such as a glass plate as an object to be inspected, uses a collimating lens for light emitted from a light source. While parallel light is projected onto the object to be inspected, reflected light from the surface to be inspected of the object to be inspected is condensed through a collimator lens, and a spot image formed on the focal plane is observed.

In such a measuring apparatus, when light can be viewed as when a tungsten lamp or the like is used as a light source, a focusing plate with a scale is arranged at a focal position of a collimating lens and connected to the focusing plate. X of the spot image to be imaged
The position in the -Y direction is read using an eyepiece.

On the other hand, when the light cannot be viewed as when a laser light source is used as a light source, an image pickup device or the like is arranged at a focal position of a collimator lens, and an image obtained by the image pickup device is displayed on a video monitor or the like. And read the spot image. FIG. 6 shows an example of such a configuration.

A measuring apparatus 100 shown in FIG. 6 includes a laser light source 2, a condenser lens 3 for condensing laser light emitted from the laser light source 2 at a first focal position 21, and a reflection mirror 5 for bending the laser light. And a collimator lens 6 that collimates the bent laser light, projects the parallel light on the test object 7, and condenses the reflected light at a second focal position 22, and a light receiving surface is located at the second focal position 22. Image sensor 9 arranged as described above. Further, a video monitor (not shown in FIG. 6) for displaying a spot image obtained by the image sensor 9 on a cathode ray tube is connected to the image sensor 9.

In the measuring apparatus 100 configured as described above, the first focus position 21 and the second focus position 22 are conjugate positions with respect to the collimator lens 6, so that the laser light emitted from the light source 2 Is the inspection surface 7 of the inspection object 7
A spot image which is reflected at 1 and is a reflection image at the first focal position 21 is formed at a second focal position 22, and this spot image is video-generated by the imaging device 9 arranged at the second focal position 22. Displayed on the monitor.

In such a measuring apparatus 100, as shown in FIG. 7, the center of gravity 92a of a spot image formed by accurately reflecting light from a parallel plane is obtained as a reference position. And the inspection surface 7 of the inspection object 7
Center position 93 of spot image 93 obtained from reflected light from 1
and a on the video monitor 92. Here, if the barycenter positions 92a and 93a overlap, it can be determined that the inspection surface 71 is not inclined. Also, the center of gravity position 9
If 2a and 93a are shifted, the inclination angle of the inspection surface 71 can be obtained from the shift amounts in the X and Y directions and the focal length of the collimator lens 6. If the formed image looks sharp without distortion, it can be determined that the flatness and the surface roughness are good.

[0008]

However, as in the measuring apparatus 100 described with reference to FIGS.
In the configuration in which the measurer observes the spot image 93 on the video monitor 92, since the eyesight and the skill level vary depending on the measurer, individual differences occur in reading the center of gravity position 93a of the spot image 93. Further, since the cathode ray tube of the video monitor 92 fills the gap between the surface and the image plane with glass, the spot image 93 projected on the video monitor 92 is formed.
Causes some displacement depending on the viewing angle.
Further, since the video monitor 92 itself adjusts the size, aspect ratio, and the like of the image by image processing, the size and position of the spot image 93 may be changed by this processing. For this reason, the conventional measuring device 100 has a problem that it is difficult to perform accurate measurement.

In view of the above problems, an object of the present invention is to provide a measuring apparatus which forms an image of reflected light from a surface to be inspected and measures an inclination angle, flatness, surface roughness, and the like based on the image.
An object of the present invention is to propose a configuration capable of accurately performing these measurements.

[0010]

In order to solve the above-mentioned problem, a measuring apparatus according to the present invention comprises a light source and a parallel light beam emitted from the light source. In a measuring device having a collimating lens to be incident and a light receiving device that receives the reflected light of the surface to be inspected through the collimating lens, the light receiving device is a position detecting element (PSD; Position Sensitive D).
ector, PositioningSensing
Device).

In the present invention, the position detecting element used as a light receiving device for receiving the reflected light from the surface to be inspected through a collimating lens is used, for example, as a two-dimensional position detecting element. It is output as numerical information as voltage values in the X and Y directions indicating the position.
Therefore, unlike the configuration in which the measurer reads the position of the center of gravity by looking at the shape of the spot image, in the present invention, by reading the output voltage value, even an unskilled person can read the position of the center of gravity of the spot image. Can be accurately determined. In addition, the position of the center of gravity can be accurately determined even from a spot image in which the position of the center of gravity is difficult to read. Further, since the position of the center of gravity of the spot image is converted into a numerical value and output, the evaluation of the quality of the inspection object from the spot image can be mechanized and labor-saving.

In the present invention, the light source is preferably a laser light source. According to this structure, light (laser light) with high luminance and high output is emitted from the light source, so that a spot image of the reflected light received by the position detection element can be detected with high accuracy.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A measuring apparatus according to the present invention will be described with reference to the drawings. Since the basic configuration of the measuring device of the present invention is the same as that of the conventional embodiment, the common portions are denoted by the same reference numerals.

[First Embodiment] FIG. 1 is a schematic block diagram of a measuring apparatus according to a first embodiment of the present invention. FIG.
3 is a graph showing a relationship between a voltage value output from a position detecting element used in the measuring apparatus shown in FIG. 1 and a center of gravity of a spot image.

As shown in FIG. 1, a measuring apparatus 1 of the present embodiment
Is an autocollimator for measuring the inclination angle, flatness, surface roughness, and the like of the surface 71 to be inspected by using a parallel flat plate such as a glass plate as the object 7 to be inspected. The laser light source 2 is used as a light source for the measurement. .

On the optical path from the laser light source 2 to the object 7 to be inspected, the laser light emitted from the laser light source 2 is condensed at a first focal position 21 and converted into a light flux having a predetermined numerical aperture. A lens 3 and a reflecting mirror 5 for bending the laser beam, which has become a light beam with a predetermined numerical aperture, toward a collimating lens 6
And a collimator lens 6 for collimating the laser beam bent by the reflection mirror 5 are arranged in this order.

In the present embodiment, a position detecting element 8 is used as a light receiving element, and the position detecting element 8 receives light at a second focal position 22 where the reflected light from the object 7 is converged by the collimating lens 6. It is arranged so that the surface is located.

Here, the first focal position 21 and the second focal position 22 are conjugate with respect to the collimating lens 6, so that the laser light emitted from the laser light source 2 is
A spot image that is reflected by the inspection surface 71 of the inspection object 7 and is a reflection image of the first focal position 21 is formed at the second focal position 22.

In the measuring apparatus 1 configured as described above, since the position detecting element 8 is used as the light receiving element, the light receiving result is quantified and output as the voltage values in the X and Y directions of the center of gravity of the spot image. . Here, the relationship between the output voltage and the position of the center of gravity of the spot image can be represented as a graph in which the amount of change in the voltage and the amount of change in the position of the spot image are proportional, as shown in FIG. If the voltage amplitude is adjusted so that the voltage change 1 V corresponds to the spot image position change 1 mm, the center of gravity of the spot image can be obtained by simply changing the unit of the output voltage from V to mm.

Therefore, the position of the center of gravity of the spot image can be obtained by reading the output value B1 of the voltage value. On the other hand, when the position B1 is shifted from the center of gravity B0 of the spot image formed by the reflected light of the accurate parallel flat plate defined at the origin of the graph, the amount of shift of the center of gravity and the collimating lens 6 From the focal length, the inclination angle of the inspection surface 71 can be obtained. Therefore, the position of the center of gravity of the spot image formed by the reflected light from the surface 71 to be inspected can be determined from the output voltage value without reading from the shape of the spot image. The judgment can be made accurately. Further, it is possible to determine a spot image having a shape in which it is difficult to read the position of the center of gravity. In addition, since the position of the center of gravity of the spot image is converted into a numerical value and output, the mechanization of the spot image determination and labor saving can be achieved.

Further, since the laser light source 2 emits high-intensity, high-output laser light, the spot image of the reflected light received by the position detecting element 8 can be detected with high accuracy.

[Second Embodiment] FIG. 3 is a schematic block diagram of a measuring device according to a second embodiment of the present invention. In addition,
Since the basic configuration of the measuring apparatus according to the present embodiment is common to that of the first embodiment, common portions are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 3, the measuring apparatus 1 of the present embodiment
The switchable mirror 51 is detachably disposed between the collimator lens 6 and the position detection element 8, and the image pickup device 9 is disposed on the reflection direction side of the switchable mirror 51.
Here, the imaging element 9 is also arranged at the focal position 23 of the collimator lens 6. Other configurations are described in Embodiment 1.
Therefore, the description thereof is omitted.

The measuring apparatus 1 of the present embodiment thus configured
Then, the reflected light condensed by the collimating lens 6 is received by the position detecting element 8 when the switchable mirror 51 is not provided, and when the switchable mirror 51 is disposed, the optical path is bent and received by the image pickup element 9. Is done. Therefore, the collimating lens 6 is switched by the switchable mirror 51.
The spot image condensed in step (1) is output by the position detection element 8 as information quantified into voltage values in the X and Y directions indicating the barycentric position of the light, and is output from the imaging element 9 as an image. From both information, the inclination angle, flatness, and surface roughness of the inspection surface 71 can be measured.

[Third Embodiment] FIG. 4 is a schematic block diagram of a measuring apparatus according to a third embodiment of the present invention. The basic configuration of the measuring apparatus according to the present embodiment is the same as that of the first and second embodiments. Therefore, the common parts are denoted by the same reference numerals, and the description thereof is omitted.

As shown in FIG. 4, the measuring apparatus 1 of the present embodiment
Is different from the second embodiment in that a half prism mirror 52 is disposed instead of the reflection mirror 5 for bending the emitted light. Further, a beam splitter 53 is disposed instead of the switchable mirror 51 that bends the optical path of the reflected light toward the image sensor 9.

The measuring apparatus 1 of the present embodiment thus configured
Then, the reflected light condensed by the collimator lens 6 is separated by the beam splitter 53 and received by the position detecting element 8 and the imaging element 9 at the same time. For this reason, in the spot image condensed by the collimating lens 6, information quantified into voltage values in the X and Y directions indicating the barycentric position of the light is output from the position detection element 8, and at the same time, the imaging element 9 outputs Since an image is output, the inclination angle, the flatness, and the surface roughness of the surface 71 to be inspected can be simultaneously measured from both of these information.

[Embodiment 4] FIG. 5 is a schematic block diagram of a measuring apparatus according to Embodiment 3 of the present invention. The basic configuration of the measuring apparatus according to the present embodiment is the same as that of the first, second, and third embodiments. Therefore, common portions are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 5, the measuring device 1 of the present embodiment
Is different from the third embodiment in that the outgoing light emitted from the laser light source 2 and the reflected light reflected from the object 7 pass on a common optical path. On a common light path,
A first beam splitter 54 that bends the light emitted from the laser light source 2 toward the collimating lens 6 and passes the reflected light from the surface 71 to be inspected that has passed through the collimating lens 6, and travels from the reflected light to the image sensor 9. A second beam splitter 55 for splitting light is provided.
Further, a dummy prism 56 is arranged between the second beam splitter 55 and the image sensor 9.

The measuring apparatus 1 of the present embodiment thus configured
Then, the reflected light collected by the collimating lens 6 is
And is simultaneously received by the position detection element 8 and the imaging element 9 by the beam splitter 55. For this reason,
The spot image condensed by the collimator lens 6 is output from the position detection element 8 as numerical information into voltage values in the X and Y directions indicating the barycentric position of the light, and is simultaneously image-output from the imaging element 9. Therefore, the inclination angle, the flatness, and the surface roughness of the inspection surface 71 can be measured simultaneously. Further, in this embodiment, the light emitted from the laser light source 2 and the light reflected on the surface 71 to be inspected have a common optical path, so that the measuring apparatus 1 can be reduced in size and thickness.

[0031]

As described above, in the measuring apparatus according to the present invention, the reflected light from the surface to be inspected is detected by the position detecting element, so that the light receiving result is the voltage in the X and Y directions indicating the position of the center of gravity of the light. The information is output as numerical information. For this reason,
By reading the output voltage value, even an unskilled person can accurately determine the position of the center of gravity of the spot image. Also,
The position of the center of gravity can be accurately determined even from a spot image in which the position of the center of gravity is difficult to read. Further, since the output of the spot image is digitized, the evaluation of the quality of the inspection object from the spot image can be mechanized and labor-saving.

If a laser light source is used as the light source,
Since the light source emits high-luminance and high-output light (laser light), the spot image of the reflected light received by the position detection element can be detected with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a measuring device according to a first embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a voltage value output from a position detecting element used in the measuring device shown in FIG. 1 and a position of a center of gravity of a spot image.

FIG. 3 is a schematic block diagram of a measuring device according to a second embodiment of the present invention.

FIG. 4 is a schematic block diagram of a measuring device according to a third embodiment of the present invention.

FIG. 5 is a schematic block diagram of a measuring device according to a fourth embodiment of the present invention.

FIG. 6 is a schematic block diagram of a conventional measuring device.

7 is an explanatory diagram showing a video monitor on which an image obtained by an image sensor of the measuring device shown in FIG. 7 is displayed.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Measuring device 2 Laser light source 3 Condensing lens 5 Reflecting mirror 6 Collimating lens 7 Inspection object 8 Position detecting element (positioning / sensing device) 9 Imaging element 21 First focus 22 Second focus 51 Switchable mirror 52 Half Prism mirror 53 Beam splitter 54 First beam splitter 55 Second beam splitter 56 Dummy prism 71 Surface to be inspected

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA37 AA47 AA50 BB01 CC21 DD00 FF01 FF43 FF61 GG04 HH03 JJ03 JJ16 LL00 SS13 TT02 UU07 5F072 KK05 KK15 KK30 YY20

Claims (2)

[Claims] 1. A light source, a collimating lens that collimates emitted light emitted from the light source and makes the collimated light enter a surface to be inspected of a device to be inspected, and a light receiving device that receives reflected light from the surface to be inspected through the collimating lens A measuring device comprising: a measuring device, wherein the light receiver is a position detecting element. 2. The measuring apparatus according to claim 1, wherein the light source is a laser light source.