JP3236090B2 - Plane azimuth measuring device, plane azimuth measuring method, and optical component inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plane azimuth measuring apparatus for measuring the plane azimuth of an optical component or the like, and more particularly to a plane azimuth measuring apparatus capable of quickly performing accurate measurement.

[0002]

2. Description of the Related Art For example, when measuring the refractive index of a prism, it is generally necessary to find the apex angle of the prism. For this purpose, the orientation of two surfaces forming the apex angle of the prism is usually measured. Ask. In the case of polyhedral mirrors such as polygon mirrors used in various optical devices, it is one of the important factors that affect the performance of the optical device whether or not the angles formed by the respective surfaces accurately form a predetermined angle. One. Even when this angle is obtained, it is general to measure the azimuth of each surface. Further, for example, when obtaining the deflection angle of a galvanomirror, it is necessary to measure the azimuth of the surface.

In order to measure the plane orientation as described above, generally,
A device using an autocollimator has been used. FIG. 18 is a diagram showing a configuration of a conventional plane orientation measuring device. In FIG. 18, a sample table 3 and a swivel arm 4 are provided on the base 2 so as to be rotatable around an axis O substantially perpendicular to the base 2. A telescope 5 for observing the light reflected from the surface to be measured of the sample 1 placed on 3 is attached. The sample table 3 is provided with a tilt angle adjusting mechanism provided with a tilt screw 3a for adjusting the tilt angle of the sample 1 mounted on the sample table 3 with respect to the horizontal direction. Is provided with an angle scale plate 2a for reading the rotation angle of the swivel arm 4, and an angle scale reading microscope 2b. The angle scale plate 2a can also be rotated around the axis O. In addition, there is a type in which a rotary encoder is provided instead of the angle scale plate 2a to display the scale digitally.

The telescope 5 has a structure that also serves as an autocollimator. That is, the telescope 5 includes an observation optical system including an objective lens 5a provided at a front part of a lens barrel and an eyepiece 5b provided at a rear part of the lens barrel, which are arranged to face a surface to be measured of the sample 1, and an objective lens. 5a is common, and is optically conjugate with the focal plane of the objective lens 5a on an optical path branched out of the observation optical system by a beam splitter 5c provided between the objective lens 5a and the eyepiece 5b. A projection optical system including a projection index 5d and a projection light source 5e provided at a position. Light emitted from the projection index 5d is reflected by the beam splitter 5c, converted into parallel light by the objective lens 5a, and emitted outside. Also,
A reference index 5f is provided on the focal plane of the objective lens 5a. When the optical axis of the light incident on the telescope 5 coincides with the optical axis of the telescope 5, the image of the incident light from the eyepiece is used as the reference index 5f. Is observed in accordance with the image of. Therefore, the telescope 5 is pointed at the surface to be measured of the sample 1, the reflected image of the projection index 5d at that time is observed, and the angle of the telescope 5 is adjusted so that the reflected image matches the image of the reference index 5f. Thus, the optical axis of the telescope can be set perpendicular to the external reflection surface, and by reading the angle of the telescope 5 at that time, the direction, that is, the direction of the normal line of the measured surface of the sample 1 can be known.

[0005]

However, the above-mentioned conventional plane orientation measuring apparatus has the following problems.

That is, in order to measure the plane orientation of the sample 1, the observer looks into the telescope 5 and observes the image of the projection target 5d and the reference index 5f, so that the telescope 5 and the reference index 5f are accurately overlapped. Although it is necessary to adjust the angle of No. 5, it is not always easy to do this accurately, and this has caused a certain limit in measurement accuracy. In addition, there is a problem that there is an individual difference in determining whether or not they are exactly the same, and there is a problem that measurement accuracy varies.

In addition, the measurement work requires concentration,
In particular, when the measurement accuracy of the angle is required to be about ± 1 second, the measurement time becomes longer and the mental fatigue of the worker is accumulated accordingly. In addition, there is a limit to the duration of concentration, and the number of measurements per unit time and the reproducibility (reliability of measured values) both decrease with the passage of time. There was also a risk that the eyesight of the measurer would decrease.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to provide a plane orientation measuring apparatus capable of quickly performing highly accurate measurement.

[0009]

According to the present invention, there is provided a plane direction measuring apparatus for measuring a plane direction of a surface to be measured of a sample, wherein: A sample table for mounting a, and a telescope provided rotatably relative to the sample around the sample mounted on the sample table,
A photographing index disposed on a plane optically conjugate with the focal plane of the objective optical system of the telescope, and a projection light source for emitting projection light obtained by illuminating the imaging index to the outside through the objective optical system A telescope comprising: a position detection type imaging element that detects an optical image formed on a focal plane by light incident through the objective optical system; and the telescope for a sample placed on the sample stage. An angle measuring device for generating an electric signal corresponding to a relative rotation angle of the telescope for projecting an image formed by the image sensor when the telescope is oriented in a predetermined direction with respect to the surface to be measured. A reference index generator for generating an image signal for superimposing and forming an image of the reference index indicating the position of the index image; and controlling the image pickup device, the angle measuring device, and the reference index generator, and an image transmitted from these. A processing device for processing a signal including a signal, wherein the processing device is configured to project a projection formed by the imaging element when the telescope is directed at a measurement target surface of a measurement target sample mounted on the sample stage. position and the group use the index image
A signal corresponding to the deviation from the position of the quasi-index image is obtained, and this
Signal and the rotation angle generated by the angle measuring device.
The present invention is characterized in that it has a function of performing a process of obtaining the azimuth of the surface to be measured from the corresponding electric signal. As an aspect of this configuration 1, (2) the surface described in the configuration 1 In the azimuth measuring device, the image sensor may include a two-dimensional image sensor arranged on a focal plane of the objective optical system and a one-dimensional image sensor arranged at a position optically conjugate with the focal plane. The configuration was characteristic. Also, the plane orientation measuring method according to the present invention is: (3) In the plane orientation measuring method for measuring the orientation of the surface to be measured of the sample to be measured, the sample is placed on a sample table, and an objective optical system; An index disposed on a plane optically conjugate with the focal plane of the objective optical system, and a position detection type image sensor for detecting an optical image formed on the focal plane by light incident through the objective optical system. The objective optical system is rotated relative to the sample, and the image of the target is placed on the focal plane, and the light constituting the image passes through the objective optical system from the target and passes through the object to be measured. Reflected by the surface, again through the objective optical system and incident on the focal plane to form an image,
The imaging device generates an electrical signal corresponding to a relative rotation angle of the objective optical system with respect to the sample, and directs the objective optical system toward a measurement surface of a measurement sample mounted on the sample stage. wherein the position of the index image formed by the
When the objective optical system is in a predetermined orientation with respect to the measurement surface,
The position of the reference index image formed by the image sensor
A signal corresponding to this is obtained, and the obtained signal and the angle measurement are obtained.
Electrical signal corresponding to the rotation angle generated from the
From which the plane orientation of the surface to be measured is obtained. The method for inspecting an optical component according to the present invention may further include: (4) measuring an angle at which the first surface and the second surface of the optical component intersect, and inspecting whether the angle is within a predetermined range. In the inspection method, the plane orientation of the first plane and the second plane is determined by the plane orientation measurement method according to claim 3, and the first plane and the second plane are determined from the first plane and the second plane orientation. An angle at which the two surfaces intersect is determined, and an optical component having the angle within a predetermined range is used as a product. (5) The optical component is a prism, and the angle is a vertex angle of the prism; and (6) the optical component is a polyhedral mirror, and the angle is Is an angle forming each surface of the polyhedral mirror.

[0010]

According to the above configuration 1, the position of the optical image formed on the image sensor is determined by image processing, and the azimuth of each surface is determined from this position, the position of the reference index, and the angle measured by the angle measuring device. You can ask. According to this,
As in the past, there is no need to precisely adjust the rotation of the telescope to accurately align the projection target image with the reference target,
It is only necessary to make a rough adjustment so that these images fall within the imaging range of the imaging device. Therefore, quick measurement is possible. In addition, since these measurements are performed by processing including image processing by the processing device, constant accuracy can always be obtained without depending on the skill or fatigue of the measurer.

According to the second aspect, for example, monitor information is mainly obtained by a two-dimensional image pickup device, and measurement information is obtained by a one-dimensional image pickup device having a high resolution. It is possible to obtain a good device.

[0012]

FIG. 1 is a diagram showing the overall configuration of a plane direction measuring apparatus according to an embodiment of the present invention. Hereinafter, an embodiment will be described with reference to FIG. Since this embodiment has many parts in common with the conventional example shown in FIG. 18 described above, common parts are denoted by the same reference numerals, and a part of the description is omitted. The explanation focuses on the points specific to the example.

In FIG. 1, a sample base 3 and a swivel arm 4 are provided on a base 21 so as to be rotatable about an axis O substantially perpendicular to the base 21. The swivel arm 4 is provided with a sample base. A telescope 51 for observing light reflected from the surface to be measured of the sample 1 mounted on 3 is attached. These points have almost the same configuration as the above-described conventional example.

This embodiment is different from the conventional example described above in that:
The telescope 51 attached to the swivel arm 4
The image pickup device 51b is provided instead of the eyepiece 5b of the telescope 5 in the above-described conventional example. In the above-described conventional example, the base 2 has the built-in angle scale plate 2a. The base 21 of the embodiment has a built-in rotary encoder 21a instead of an angle scale plate, and controls the image pickup device 51b and the rotary encoder 21a to process information from them and to perform necessary calculations and display. Image processing / processing device with display function (hereinafter, abbreviated as processing device) 9 and image pickup device 51
The reticle generator 10 for generating a reference index to be displayed so as to be superimposed on the image taken by b is newly provided.

Here, the rotary encoder 21 a provided on the base 21 generates a signal corresponding to the rotation angle coordinates of the sample table 3 and the swivel arm 4 and sends the signal to the processing device 9.

The telescope 51 is the conventional example described above,
Has the same configuration except that an image sensor is provided instead of the eyepiece lens 5b. That is, FIG. 2 is a view showing the telescope 51. As shown in FIG. 2, the telescope 51 has a structure similar to that of the autocollimator, and is arranged to face the surface of the sample 1 to be measured. Objective lens 51a provided at the front of the lens barrel and the objective lens 51a
Image pickup device 51 provided at the focal position of
b, and the objective lens 51a is made common, and the image pickup device is formed on an optical path branched out of the observation optical system by a beam splitter 51c provided between the objective lens 51a and the image pickup device 51b. The projection optical system includes a projection index 51d and a projection light source 51e provided at a position optically conjugate with the projection index 51b. The light of the projection index 51d is reflected by the beam splitter 51c, converted into parallel light by the objective lens 51a, emitted outside, and incident on the sample surface. The light reflected by the measured surface of the sample 1 is condensed by the same objective lens 51a, passes through the beam splitter 51c, and enters the image pickup device 51b arranged at a position optically conjugate with the projection target 51e. Focus.
That is, the image of the projection target 51d is formed on the image sensor 51b. In this embodiment, a double crosshair as shown in FIG. 3 is used as the projection index 51d, but another form that performs the same function may be used. When the optical axis of the telescope 51 is perpendicular to the sample surface, the image of the projection target 51d forms an image at a reference position, for example, a position of an optically adjusted reticle to be described later. The above is well known as the principle of autocollimation.

The image sensor 51b is, for example, a two-dimensional CCD.
As described above, a large number of photodetectors are arranged on a plane and each is a pixel, and is controlled by the processing device 9,
The light image formed by the objective lens 51a is converted into an electric signal and transmitted to the processing device 9.

The processing device 9 includes necessary circuits such as a microprocessor and other information processing circuits and has a display 9a for display. The processing device 9 is operated in accordance with a predetermined program stored in advance by a predetermined command. It controls the encoder 21a, the imaging element 51b, and the reticle generator 10 and executes processing of an angle signal, an image signal, and other signals sent from the encoder 21a, necessary calculation, or processing for performing display.
The specific function of the processing device 9 will be described later together with the procedure for performing the measurement using the device of the present embodiment.

As shown in FIG. 4, the reticle generator 10 displays the reference index 5 of the above-described conventional example on a screen on which an image formed by the image sensor 51b is displayed.
Vertical reticle 51 as a reference index that performs the same function as f
fv and an image signal for displaying the horizontal reticle 51fh. These reticles 51fv and 51fh can be adjusted up, down, left and right, but are fixed after the adjustment (alignment) of the optical system. Projection index 5
When the image of 1d is captured by the image sensor, an image in which both images are combined is displayed on the screen as shown in FIG. Then, when the optical axis of the telescope 51 is perpendicular to the sample surface, as shown in FIG.
1fv and the horizontal reticle 51fh are located at the center of the double line of the projection index 51d.
Of the sample surface indicates the orientation of the sample surface as it is.

If the measurer (operator) can observe the output (angle information) from the rotary encoder 21a in real time, the efficiency of the operation work is improved. Therefore, if necessary, the rotary encoder and the image processing / computing device can be used. An angle indicator may be provided between the two.

Further, in a display device of a normal image processing apparatus, the image display is fixed at the time of processing, so that it is impossible to observe an image by the image pickup device at the time of processing in real time. Therefore, it is preferable that an image observation monitor is provided between the reticle generator 21a and the processing device 9 so that an image obtained by the image sensor can be observed in real time even during processing so that the operation work can be easily performed. Further, the processing device 9 described above can be replaced with a configuration including an image processing device and a personal computer, or a configuration including an image processing device, a personal computer, and a monitor.

Now, an example will be described in which the apparatus of the above-described embodiment is used to measure the azimuth of two surfaces forming the apex angle of the prism using the prism as a sample to obtain the apex angle of the prism. . 7 and 8 are explanatory diagrams of a method for measuring the apex angle of the prism using the apparatus of the present embodiment. FIG.
8 and FIG. 8, the vertex angle of the prism 1 is Φ, and two surfaces forming the vertex angle are A and B. In the method shown in FIG. 7, the telescope 51 is turned to the planes A and B by rotating the telescope 51 while the sample table 3 is fixed, and these plane directions are measured. On the other hand, in the example shown in FIG. 8, the surfaces A and B are directed to the telescope 51 by rotating the sample table 3 while the telescope 51 is fixed, and the plane directions are measured. The apex angle can be measured by any of these methods. Hereinafter, an example in which the apex angle is measured by the method shown in FIG. 7 will be described.

The apex angle の of the prism 1 is given by Φ = φ with respect to the direction a (vector) of the surface A and the direction b (vector) of the surface B.
There is a relationship that satisfies π− | ab |. Here, the azimuth a of the surface A and the azimuth b of the surface B are synonymous with a normal vector representing the direction of the normal to each surface. Note that the magnitude of the vector is 1 (unit vector). The vector is measured using the telescope 51 as an autocollimator. In this case, as shown in FIG.
Thus, angles Θ and の in polar coordinates, which are parameters representing the directions of the planes A and B (hereinafter, referred to as sample planes), are measured. Here, the rotation angle of the swivel arm 4 is Θ (detected value of the rotary encoder 21a), and the angle in the direction perpendicular to the plane including the rotation direction of the swivel arm 4 is ψ. The origin of the coordinate axes is the intersection between the rotation center axis of the swivel arm 4 and the sample mounting surface of the sample table 3. The direction of the sample surface is adjusted by moving the swivel arm in the direction Θ and by tilting the sample stage 3 in the direction ψ.

When the optical axis of the telescope 51 is set so as to be substantially perpendicular to the sample plane orientation, the display 9a is displayed as shown in FIG.
The display as shown in FIG. In FIG.
Now, considering the luminance distribution of an image for one line (width of one pixel) indicated by a horizontal broken line α, the result is as shown in FIG. The horizontal axis in FIG. 11 is the horizontal distance, and the vertical axis is the luminance level. The position of each component of the image formed on the imaging element 51b corresponds to a specific pixel for detecting the component. Therefore, in principle, the position of the component of the image is obtained from, for example, the position from the left of the pixels constituting the image sensor 51b. Actually, it is obtained by adding a predetermined process to the image processing.

In FIG. 11, if the position of the double line of the projection index 51d and the position of the reticle 51fv are obtained, the distance d between the center of the double line and the center of the reticle can be obtained. That is, the positions of the double lines are x ₁ and x ₂ , respectively, and the reticle 5
When the position of 1fv and x _3, the distance d is expressed by the following equation (1).

D = x _3- (x ₁ + x ₂ ) / 2 (1) Here, to obtain x ₁ , x ₂ , x ₃ , the reticle 51
It is necessary to distinguish fv from the projection index 51d, and since these have a width, it is necessary to find the center position of the width. Hereinafter, the method will be described.

First, a reticle 51fv and a projection index 51d
There are several ways to distinguish between For example, (a) change line type, (b) change line thickness, (c) change line color, (d) use optical properties, (e) adjust reticle length. For example, a method of judging from a difference in length between the reticle and the index image can be considered. Where (a) ~
Since the methods (c) and (e) are self-evident, the description will be omitted, and the method (d) will be described below.

When representing the density of an image in image processing, data of 8-bit length is generally used. If this is made to correspond to the density (brightness of the image), it can be distinguished into 128 gradations (128 steps) (of course, there is no need to stick to 8-bit data, and any number of bits can be used if the gist of the present invention can be realized). Here, the image of the projection target 51d projected on the image sensor 51b does not form a strict rectangular pattern because it passes through the optical system. That is, due to the imaging characteristics of the optical system, a bell-shaped luminance distribution with a slightly wider tail is obtained. On the other hand, in the case of a reticle, a completely rectangular pattern can be created because an image is formed electrically (of course, any pattern can be created electrically and any pattern that can be distinguished from the index image). Anything is fine). Both can be distinguished from this difference in shape. That is, as shown in FIG. 12, one peak is focused on, and the level with the highest luminance in the peak is set to 100%. 90%, 80%…
Thus, luminance levels (also called slice levels and binarization levels) are provided at appropriate intervals. When the widths of the peaks at this level are obtained, when a bell-shaped pattern is shown, the width becomes wider as the level is lowered. On the other hand, as shown in FIG. 13, in the case of an electrically created reticle, the width does not change even if the level is changed. In this way, it is determined whether the image obtained by the imaging element 51b is the projection target 51d or the reticle 51fv.

A reticle 51fv and a projection index 51d
The center position of the image is determined as follows. As shown in FIG. 14, for example, the width L at an appropriate slice level
₂ is determined, and the midpoint is determined as the center of the image. Next, to measure the distance L ₁ of the first to the pixel exceeding the slice level counted from the end of the image receiving region of the imaging device 51b. Then, the center position L _{C of the} peak is obtained by the following equation (2).

[0030] _{L C = L 1 + L 2} /2 ...... (2) By the way, each of the light detection element constituting the pixels of the image pickup device 51b has a finite size. Therefore, it is theoretically difficult to measure a distance smaller than the pixel.
Therefore, the measured value includes an error of plus or minus one pixel. This is called a quantization error. To reduce this quantization error, a plurality of L ₁ , L
Find ₂ and take their average. For example, (a) determining the center at a plurality of slice levels in FIG. 14 or (b) setting a plurality of lines corresponding to the lines (α, β) in FIG. Can be higher. Of course, you can use the entire data.
Alternatively, (c) slightly moving the position of the telescope 51, or (d) moving the image sensor 51b perpendicular to the optical axis to change the relative position between the reticle and the projection target image. . Further, (e) the imaging element 51b is moved in parallel to the optical axis to create a slightly out-of-focus state and perform the same operation to improve the measurement accuracy. Further, these may be arbitrarily combined or all may be combined. Further, apart from the above method, there is also a method of obtaining a peak using a smoothing differential method based on data on a line corresponding to the line α in FIG.

Next, the distance d thus obtained is converted into the rotation angle of the telescope 51. This conversion is obtained by the following equation (3), where Δx is the rotation angle of the telescope 51 to be obtained and f is the focal length of the objective lens.

TanΘx = d / f (3) The precision of the distance d depends on the precision of the size of one pixel constituting the image sensor 51b. However, in some cases, it is conceivable that the relationship between の x and d cannot be theoretically obtained when the size of the pixel or the focal length of the lens cannot be obtained accurately or for other reasons. In such a case, a calibration experiment is actually performed, and the relationship between Δx and d is determined based on the results.

If the angle representing the current position of the telescope 51 is Θn, it is possible to determine the position of the telescope 51 when the projection index image matches on the reticle using θn and θx obtained previously. it can. That is, assuming that the angle at this time is θL, ΘL is given by the following equation from Θn and Θx.
It is obtained by equation (4).

ΘL = Θn + Θx (4) Similarly, ψcoordinates (y direction on the screen) Θy can be obtained.

ΘL and Θy obtained above correspond to the angle parameters when the direction of the normal vector of the sample surface is represented by polar coordinates. Therefore, ΘL and Θy are θ and
そ れ ぞ れ is defined as the direction of the sample surface. Then, the vector component of the orthogonal coordinate system of the normal vector a surface _{A (a 1, a 2,} a 3) is expressed as _{a 1 = sinθa · cosψa a 2} = sinθa · sinψa a 3 = cosθa.

Next, the above-described operation is performed on the other surface B of the prism 1, and the sample plane orientation is similarly obtained. The vector components (b ₁ , b ₂ , b ₃ ) of the normal vector b of the exit surface B in the orthogonal coordinate system are expressed as b ₁ = sin θb · cosψb b ₂ = sin θb · sinψb b ₃ = cos θb.

Assuming that the angle between these vectors a and b is φ, φ can be obtained from the following equation (5) using the formula of the inner product of the vectors.

[0038] _{^{φ = cos -1 {(a 1}} b 1 + a 2 b 2 + a 3 b 3) / (a 1 2 + a 2 2 + a 3 2) 1/2 (b 1 2 + b 2 2 + b 2 2) 1 ^{/ 2} ｝ (5) where 0 ≦ φ ≦ π.

When φ is obtained in this manner, the vertex angle Φ of the prism 1 can be obtained from the following equation (6). Φ = π−φ (6) (Modification) In the above-described embodiment, an example in which a two-dimensional image sensor is used as the image sensor 51b provided in the telescope 51 has been described. As shown in (1), a one-dimensional image sensor with high resolution may be used in addition to the two-dimensional image sensor.

In the telescope 52 shown in FIG. 15, a two-dimensional image pickup device 52b is arranged at a focal position of an objective lens, and a beam splitter 52c and a two-dimensional image pickup device 52b forming an optical path of a projection index 52d and a projection light source. A second beam splitter 52g is disposed between the two, and a one-dimensional image sensor 52f is provided on the reflected light path of the beam splitter 52g via relay lenses RL1 and RL2 at a position optically conjugate with the two-dimensional image sensor. It is a thing. Thus, the image obtained by the two-dimensional image sensor 52b is mainly used for monitoring, and the data for measurement has a high resolution and a wide measurement range.
This can be obtained by the two-dimensional imaging device 52f, and measurement with a high resolution and a wide measurement range can be performed. That is, the number of pixels of currently marketed two-dimensional sensors (image sensors) is generally 510 pixels in both the x and y directions, and at most about 1000 pixels even in the high-resolution type. It is commercially available up to pixels. By appropriately selecting the relay lenses RL1 and RL2 (or a zoom lens), the measurement range can be made wider or finer (resolution can be increased). For example, when trying to obtain high resolution, the measurement range may be narrowed. In this case, rough position information can be obtained by the two-dimensional sensor, and guide information to be introduced into the effective measurement range of the one-dimensional sensor can be output. The signal obtained by the one-dimensional sensor is exactly the same as that shown in FIG. Here, in order to measure the line (broken line) β direction, a rotation mechanism is provided in the mount portion of the one-dimensional sensor, and the sensor is rotated 90 degrees around the optical axis, or between the RL1 and RL2, An image is rotated by arranging a prism element for image rotation.

Incidentally, the example shown in FIG.
Since there is one dimension sensor, only one angle (for example, the α direction in FIG. 10) can be measured by one operation. Therefore, when trying to measure both α and β directions, a rotating mechanism must be provided. In contrast, the telescope 53 shown in FIG. 16 uses two one-dimensional sensors,
By arranging each orthogonally around the optical axis, without using a mechanical drive such as a rotating mechanism,
It is possible to simultaneously measure both directions of the broken lines α and β shown in FIG. That is, in FIG.
The one-dimensional image sensor 53f, the relay lens RL1, and the relay lens RL2 are respectively provided with the telescope 52 shown in FIG.
One-dimensional image sensor 52f, relay lenses RL1, RL2
But these two relay lenses RL1 and RL
2 and a third beam splitter 53h is arranged to
An optical path branched from the optical path of the optical system of the three-dimensional image sensor 53f is formed, and the third relay lens RL3 and the second
Is provided with the one-dimensional imaging device 53i.

In the telescopes 52 and 53, the two-dimensional imaging devices 52b and 53b are used to simply observe (monitor) images.
In order to function as an eyepiece, this can be replaced with an eyepiece.

Further, as shown in FIG. 17, this telescope 51 is used instead of the telescope 51 shown in FIGS.
Of the objective lens 51a in place of the objective lens 51a in
A concave mirror 54a and a plane mirror 54j that perform the same function as a.
May be used.

According to the embodiment described in detail above, the position of an optical image formed in the telescope is determined by image processing using an image pickup device in order to determine the sample plane orientation. Thus, accurate position measurement of an optical image can be performed without performing an operation for accurately matching the image of a projection target, and accurate measurement can be performed very quickly. In addition, by performing image processing using an image sensor, a series of measurement data can be automatically input directly to an information processing device such as a computer without manual operation, thereby enabling a worker In this manner, the fatigue caused by the operation can be minimized, the measurement accuracy can be stabilized, and the measurement time can be shortened.

With the plane orientation measuring apparatus according to this embodiment,
When the refractive index measurement operation was actually performed and the comparison with the conventional method was performed, the measurement time was about 20% (reduced by 80%). In addition, the accuracy of the measurement is almost the same as that obtained when a skilled person performs the method with great care. Further, the repetition stability of the measured value was confirmed to be improved by about 30%.

[0046]

As described in detail above, the plane direction measuring apparatus according to the present invention has a position detecting type image pickup device arranged on the focal plane of the objective optical system of the telescope for observing the plane direction of the sample, and the image pickup apparatus is provided with the position detection type image pickup element. The position of the optical image is obtained by performing processing including image processing by the processing device on the optical image obtained by the element, and the position of the optical image and the position of the reference index formed by the reference index generation device and the angle measurement value by the angle measurement device Thus, the orientation of each surface is obtained from This eliminates the need to accurately adjust the rotation of the telescope to accurately align the projection target image with the reference target, as in the past, enables quick measurement, and improves the skill and fatigue of the measurer. Thus, a constant accuracy can be always obtained without depending on.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a plane orientation measuring apparatus according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a telescope 51.

FIG. 3 is an explanatory diagram of a projection index 51d.

FIG. 4 is an explanatory diagram of a reticle image.

FIG. 5 is an explanatory diagram of a projection target image and a reticle image.

FIG. 6 is an explanatory diagram of a projection target image and a reticle image.

FIG. 7 is an explanatory diagram of a method of measuring a vertex angle of a prism.

FIG. 8 is an explanatory diagram of a method of measuring a vertex angle of a prism.

FIG. 9 is an explanatory diagram of parameters representing the directions of the prism surfaces A and B.

FIG. 10 is an explanatory diagram of a display image on a display 9a when the telescope 51 is turned to a prism surface.

11 is a diagram illustrating a luminance distribution of an image for one line indicated by a horizontal broken line α in FIG. 10;

FIG. 12 is an explanatory diagram of a method for obtaining a center position of a width of an optical image.

FIG. 13 is an explanatory diagram of a method for obtaining a center position of a reticle width.

FIG. 14 is an explanatory diagram of a method for obtaining a center position of an optical image.

FIG. 15 is a diagram showing a configuration of a modification of the telescope.

FIG. 16 is a diagram showing a configuration of a modification of the telescope.

FIG. 17 is a diagram showing a configuration of a modification of the telescope.

FIG. 18 is a diagram showing a configuration of a conventional plane orientation measuring device.

[Description of Signs] 1 ... Prism, 2 ... Base, 3 ... Sample stand, 4 ... Swivel arm, 5,51,52,53,54 ... Telescope, 9 ...
Processing device, 10 ... reticle generator, 5a, 51
a, 52a, 53a ... objective lens, 51b, 52b, 5
3b, 52f, 53f, 53i: Image sensor, 5c, 51
c, 52c, 52g, 53c, 53h, 53g... beam splitter, 5d, 51d, 52d, 53d... projection index, 5e, 51e, 52e, 53e.
L1, RL2, RL3 ... Relay lens.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 G02B 27/30

Claims (6)

(57) [Claims] 1. A plane direction measuring apparatus for measuring a plane direction of a surface to be measured of a sample, comprising: a sample stage on which the sample is mounted; and a sample stage around the sample stage mounted on the sample stage. A telescope provided rotatably relative to the sample, a photographing index disposed on a plane optically conjugate with a focal plane of an objective optical system of the telescope, and an illumination of the photographing index. A projection light source for projecting the projection light obtained through the objective optical system to the outside, and a position detection type image sensor for detecting an optical image formed on a focal plane by light incident through the objective optical system. A telescope provided with: an angle measuring device that generates an electric signal corresponding to a relative rotation angle of the telescope with respect to a sample placed on the sample stage; and an object to be measured on an image formed by the imaging device. Of the telescope against the plane A reference index generator that generates an image signal that is formed by superimposing a reference index image indicating the position of the projection index image when the orientation is in a predetermined direction, and the image sensor, the angle measurement device, and the reference index generator. And a processing device for processing a signal including an image signal transmitted from the control device, wherein the processing device directs the telescope toward the surface to be measured of the sample to be measured placed on the sample stage. Sometimes the position of the projection target image formed by the imaging device and the position of the reference target image
A signal corresponding to the deviation from the position is obtained, and the obtained signal is
The electric power corresponding to the rotation angle generated from the angle measuring device
A plane azimuth measuring apparatus having a function of performing a process of obtaining an azimuth of a measured surface from an air signal . 2. The plane orientation measuring apparatus according to claim 1, wherein the image sensor is located at a position optically conjugate with the two-dimensional image sensor arranged on a focal plane of the objective optical system. A plane direction measurement device, comprising: a one-dimensional imaging device arranged. 3. A plane orientation measuring method for measuring an orientation of a surface to be measured of a sample to be measured, wherein the sample is placed on a sample stage, and an objective optical system; An index disposed on a plane conjugate to the target, and a position detection type imaging element that detects an optical image formed on the focal plane by light incident through the objective optical system, and the objective is placed on the sample. By rotating the optical system relatively, the image of the target on the focal plane, the light constituting the image passes from the target through the objective optical system, is reflected by the surface to be measured, and again the objective optical system Passing through the focal plane to form an image, generating an electrical signal corresponding to a relative rotation angle of the objective optical system with respect to the sample, and mounting the objective optical system on the sample stage When the imaging element is turned toward the surface to be measured of the sample to be measured, The objective optical system is located with respect to the position of the index image formed by the element and the surface to be measured.
The base formed by the image sensor when in a certain orientation
A signal corresponding to the deviation from the position of the quasi-index image is obtained, and this
Signal and the rotation angle generated by the angle measuring device.
The plane orientation of the surface to be measured is determined from the corresponding electrical signal.
A plane orientation measuring method characterized in that: 4. An optical component inspection method for measuring an angle at which a first surface and a second surface of an optical component intersect with each other and inspecting whether the angle is within a predetermined range. The plane orientation of the first plane and the second plane is obtained by a plane orientation measurement method, and the angle at which the first plane and the second plane intersect is obtained from the first plane and the second plane orientation, and the angle is obtained. A method for inspecting an optical component, wherein an optical component within a predetermined range is used as a product. 5. The method according to claim 4, wherein the optical component is a prism, and the angle is a vertex angle of the prism. 6. The method according to claim 4, wherein the optical component is a polyhedral mirror, and the angle is an angle forming each surface of the polyhedral mirror.