JP2000329531A - Apparatus and method for measurement of three- dimensional shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the measuring accuracy of a three-dimensional shape improvable without being influenced by the optical aberration of an optical system. SOLUTION: A laser light source 21, a collimating lens 23 which changes a laser beam into a parallel luminous flux 22, a semitransparent mirror 24a which branches the parallel luminous fluxes 22 into two parallel luminous fluxes 22a, 22b, Galilean optical systems 26a, 26b which convert the parallel luminous fluxes 22a, 22b into beltlike luminous fluxes 25a, 25b, and galvanomirrors 27a, 27b which reflect the beltlike luminous fluxes 25a, 25b so as to change their irradiation direction constitute an illumination means 20. An objective lens group 31 which condenses measuring light from an object 6 to be measured and a reflecting mirror 32 which reflects light passed through the objective lens group 31 constitute an objective optical system 30. The objective lens group 31 is constituted in such a way that its focus can be moved. A light receiving means 40 is constituted in such a way that a plurality of photoelectric conversion elements are arranged side by side two-dimensionally. The light receiving means 40 is arranged in such a way that one row of the photoelectric conversion elements agrees with a position which is conjugate with the focus of the objective optical system 30.

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 apparatus and method for measuring a three-dimensional shape of a mechanical part or other object without contact.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring the three-dimensional shape of an object in a non-contact manner, a method of optically measuring is known. This optical measuring method is roughly divided into four methods as follows. being classified.

A first method is based on triangulation, and is called a light-section method in which a three-dimensional shape is measured by detecting a direction and a distance from a light-emitting portion to an object to be measured. . This method is capable of relatively high-precision measurement with a simple configuration including a light-emitting unit and a light-receiving unit, but, depending on the shape of the measurement target, a blind spot in measurement is likely to occur,
Further, it has a disadvantage that it is easily affected by the surface condition of the measurement object.

In the second method, a predetermined regular optical pattern is projected onto a measurement object, and the three-dimensional shape is measured by detecting the degree of change of the optical pattern. This method also allows high-precision measurement with a relatively simple configuration, but also has the disadvantage that the blind spot in measurement is large.

A third method is to project a light beam on a measuring object like a radar, measure the time required for the reflected light to reach a light receiving section, calculate a distance, and calculate a three-dimensional distance from a projection position. It measures the shape. This method is suitable for measuring a long distance, but is not suitable for measuring the shape of a general small mechanical part with high accuracy.

A fourth method is to project light onto a measurement object, measure a distance by detecting a peculiar behavior of reflected light at a focal point of an optical system, and form a three-dimensional shape from a relationship with a light projection position. For measuring, there are a knife edge method, an astigmatism method, a confocal detection method, and the like.

The knife-edge method utilizes, for example, the inversion of the shadow of the knife-edge at the detector at the focal point. The astigmatism method uses an optical system having astigmatism to form the spot light. Changes from a vertically long shape to a horizontally long shape at the focal point.

In the confocal detection method, as shown in FIG. 15, the object to be measured 100 is moved within a predetermined range including the focal point of the confocal optical system 101, and a first pinhole is located at a position conjugate with the focal point. 102 and the second pinhole 10
3, the illumination light from the light source 104 emitted from the first pinhole 102 is narrowed down by the confocal optical system 101, projected on the measurement object 100, reflected and scattered, and the light from the measurement object 100 is again reflected. The light passes through the confocal optical system 101 and is detected by a light receiving unit 105 provided immediately after the second pinhole 103.

The fourth method is based on a change occurring at the focal position, and therefore can perform measurement with higher resolution than the first to third methods. Further, in the confocal detection method, when the surface of the measurement target 100 coincides with the focus of the confocal optical system 101, light is most strongly observed in the light receiving unit 105, so that measurement can be performed with very high resolution.

[0010]

In the first to third methods, the shape information is obtained when measuring light from the object to be projected is measured, whereas in the fourth method, the shape information is obtained. Since the shape information cannot be obtained until the position where the intensity of the measurement light is maximized is scanned by scanning over the entire measurement object, there is a disadvantage that the measurement requires more time than the first to third methods. Further, the fourth method has a disadvantage that the optical system has a complicated configuration, and an advanced optical design is required to suppress the aberration.

In the conventional confocal detection method shown in FIG. 15, the light emitted from the light source 104 is reflected and scattered on the surface of the measurement object 100 via the confocal optical system 101, and the light is again reflected on the confocal optical system. Since the light is received by the light receiving unit 105 via the system 101, the optical aberration has a double effect.

FIG. 16 shows a light intensity distribution (point image distribution) when the light from the point light source 104 passes through the optical system 101 having a certain wavefront aberration once, and FIG.
The light intensity distribution (point image distribution) when the light is specularly reflected at 0 and passes through the same optical system 101 again, that is, passes through the optical system 101 twice is shown. The peak of the point image distribution in FIG. 17 is significantly lower than that in FIG. 16, and it can be seen that the image is extremely deteriorated when the light passes through the optical system having the aberration twice.

As described above, when the light passes through the optical system 101 twice, it is very difficult to realize an optical system having high optical performance over the entire area of the light from the light source 104. For example, Japanese Patent Application Laid-Open No. 5-332733 discloses a confocal detection method including a confocal optical system. However, light from a measurement target passes through the optical system twice,
It again has the disadvantages mentioned above.

Further, when the confocal optical system has a zoom function, a very sophisticated optical design and a complicated and high-precision optical system are required to keep the optical aberration small over the entire zoom range. Required.

The confocal optical system 101 used in the conventional confocal detection method shown in FIG.
Since the measurement light having various intensities, such as specular reflection light and scattered light from the surface of the light receiving unit 105, is incident on the light receiving unit 105, the variation width of the level of the light intensity incident on the light receiving unit 105 is extremely small. And the dynamic range of the light receiving unit 105 is exceeded.

An object of the present invention is to solve the above problem and to provide a three-dimensional shape measuring apparatus capable of improving measurement accuracy without being affected by optical aberration of an optical system.

It is another object of the present invention to provide a three-dimensional shape measuring apparatus and a method for shortening the measuring time without reducing the measuring accuracy.

Further, the present invention reduces the variation of the light intensity of the light incident on the light receiving section due to the difference in the reflection characteristics caused by the surface properties of the object to be measured. An object of the present invention is to provide a shape measuring device.

[0019]

According to a first aspect of the present invention, there is provided an illumination means for illuminating an object to be measured with two light beams which are irradiated from different directions and intersect at a predetermined position, and the illumination means illuminated by the illumination means. An objective optical system that captures measurement light from a measurement target, and a light receiving unit in which a plurality of photoelectric conversion elements are arranged, wherein the plurality of photoelectric conversion elements are respectively measured by the objective optical system. It is characterized by receiving light and outputting an electric signal corresponding to the received light intensity.

According to this configuration, the illumination means irradiates the light from different directions and intersects at a predetermined position.
The measurement target is illuminated by the two light beams, measurement light from the illuminated measurement target is captured by the objective optical system, and the captured measurement light is received by the plurality of photoelectric conversion elements, and an electric signal corresponding to the received light intensity is generated. By being output, the illumination means and the objective optical system are separated, and the two light beams pass through the objective optical system only once, so that the influence of the aberration of the objective optical system is reduced.

Further, irradiation is performed from different directions.
By being illuminated by the two light beams, one of the light beams reaches the surface of the measurement target, and the measurement target having various shapes is prevented from becoming a measurement blind spot.

According to a second aspect of the present invention, in the three-dimensional shape measuring apparatus according to the first aspect, each of the two light beams is a collimated light beam.

According to this configuration, the illumination of the object to be measured 2
Since each of the two light beams is a collimated light beam, the received light intensity of the measurement light received by the light receiving unit becomes stable, and the measurement accuracy is improved.

According to a third aspect of the present invention, in the three-dimensional shape measuring apparatus according to the first aspect, each of the two light beams is a light beam converging in the vicinity of the predetermined position crossing each other. And

According to this structure, the illumination of the object to be measured 2
Each of the two light beams is a light beam converging in the vicinity of the predetermined position intersecting with each other, so that when the measurement target is irradiated in the vicinity of the predetermined position, the intensity of the measurement light received by the light receiving means is high. And the measurement accuracy is improved.

According to a fourth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the first aspect, the light receiving means comprises a plurality of photoelectric conversion elements arranged two-dimensionally. Features.

According to this configuration, the measurement light taken in by the objective optical system is received by the plurality of photoelectric conversion elements arranged two-dimensionally, so that two light beams illuminating the object to be measured are emitted. When there is a spread, a plurality of photoelectric conversion elements receive light, and the time required for shape measurement of the measurement target is reduced.

According to a fifth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the fourth aspect, the objective optics of the light beam when the object to be measured is irradiated with at least one of the two light beams. Position determining means for determining the position of the surface of the measurement object in the optical axis direction based on the irradiation angle with respect to the optical axis of the system and the position of the photoelectric conversion element of the light receiving means that has received the measurement light. It is characterized by having.

According to this configuration, when the object to be measured is irradiated with at least one of the two light beams, the irradiation angle of the light beam with respect to the optical axis of the objective optical system and the measurement light of the light receiving means are received. By determining the position of the surface of the measurement target in the optical axis direction of the objective optical system based on the position of the photoelectric conversion element thus determined, the shape of the measurement target can be easily measured according to the triangulation method. .

According to a sixth aspect of the present invention, in the three-dimensional shape measuring apparatus of the fifth aspect, there is provided an intersection moving means for moving a position of the intersection where the two light beams intersect in a predetermined direction. Features.

According to this configuration, the position of the intersection where the two light beams intersect moves in a predetermined direction, for example, in the optical axis direction of the objective optical system. This is performed, for example, by changing the angle of the reflecting mirror when a reflecting mirror that reflects a light beam output from the light source toward the measurement target is provided. With this, even when it is difficult to move the measurement target at high speed due to the weight of the measurement target or the like, the surface of the measurement target can be quickly covered with the two light beams, and the shape measurement of the measurement target is preferable. Done in

According to a seventh aspect of the present invention, there is provided the three-dimensional shape measuring apparatus according to the fifth aspect, further comprising a sample moving means for moving the object to be measured in a predetermined direction.

According to this configuration, the object to be measured is in a predetermined direction,
For example, by moving in the optical axis direction of the objective optical system, 2
The surface of the measurement target is easily covered with the two light beams, and the shape measurement of the measurement target is suitably performed.

According to an eighth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the first aspect, each of the two light fluxes is a strip-shaped light flux intersecting linearly with each other.

According to this configuration, the illumination of the object to be measured 2
The two luminous fluxes are band-shaped luminous fluxes intersecting linearly with each other, so that the band-shaped measurement light from the measurement target is received by the light receiving means in which a plurality of photoelectric conversion elements are arranged. It is possible to reduce the time required for measuring the shape of the object. In particular, when a plurality of photoelectric conversion elements are two-dimensionally arranged as a light receiving unit, a band-like measurement light from a measurement target is simultaneously received by the plurality of photoelectric conversion elements,
The time required for measuring the shape of the measurement object is reduced.

According to a ninth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the first aspect, the position of the intersection of the two light beams coincides with the focal point of the objective optical system. It is characterized by:

According to this configuration, since the position of the intersection of the two light beams and the focal point of the objective optical system are configured to coincide, if the surface of the object to be measured further coincides with the coincident position, The level of the measurement light taken into the objective optical system is maximized, and the surface position of the measurement target can be easily determined.

According to a tenth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the ninth aspect, an opening angle of the objective optical system is smaller than an irradiation angle of the two light beams with respect to an optical axis of the objective optical system. It is characterized by being constituted so that it becomes.

According to this configuration, the aperture angle of the objective optical system is configured to be smaller than the irradiation angle of the two light beams with respect to the optical axis of the objective optical system. The specularly reflected light from the light is hardly incident, and only the scattered light is incident. This causes the level of change in the level of the measurement light taken into the objective optical system to be narrow for various measurement targets with different reflection characteristics. Thus, an electric signal corresponding to the light receiving intensity is suitably output from the light receiving means.

According to an eleventh aspect of the present invention, in the three-dimensional shape measuring apparatus according to the tenth aspect, the light receiving means is arranged in a row arranged at a position conjugate with the focal point of the objective optical system with respect to the objective optical system. It is characterized by including a photoelectric conversion element.

According to this configuration, since the light receiving means includes a row of photoelectric conversion elements arranged at a position conjugate with the focal point of the objective optical system with respect to the objective optical system, the light receiving means is arranged at this conjugate position. When the level of the electric signal output from the one row of photoelectric conversion elements is used, when the position of the intersection of the two light beams and the focal point of the objective optical system coincide with each other and the surface of the measurement object coincides, the photoelectric The level of the electric signal output from the conversion element is maximized, and the surface position of the measurement target can be easily and accurately determined.

According to a twelfth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the eleventh aspect, the focus moving means for moving the focal point of the objective optical system in the optical axis direction and the plurality of photoelectric conversion elements. Position determining means for determining the position of the focal point when the output electric signal is at a maximum as the surface position of the measurement target.

According to this configuration, when the focal point of the objective optical system moves in the optical axis direction by the focal point moving means, the position of the intersection of the two light beams coincides with the focal point of the objective optical system. Therefore, when the focal point of the objective optical system coincides with the surface of the measurement target, the level of the measurement light taken into the objective optical system becomes maximum. Therefore, by determining the position of the focal point when the electric signals output from the plurality of photoelectric conversion elements are maximum as the surface position of the measurement target, the three-dimensional shape of the measurement target can be measured easily and with high accuracy. Will be

According to a thirteenth aspect of the present invention, there is provided the three-dimensional shape measuring apparatus according to the eleventh aspect, wherein the sample moving means for moving the object to be measured in the optical axis direction and the plurality of photoelectric conversion elements are output. Position determining means for determining the surface position of the measurement target based on the amount of movement of the measurement target when the electric signal is at a maximum.

According to this configuration, when the object to be measured moves in the optical axis direction by the sample moving means, the position of the intersection of the two light beams and the focal point of the objective optical system are matched. When the focal point of the objective optical system coincides with the surface of the object to be measured, the level of the measurement light taken into the objective optical system is maximized. Therefore, the surface position of the measurement target is determined based on the movement amount of the measurement target when the electric signals output from the plurality of photoelectric conversion elements are maximum, so that the three-dimensional shape of the measurement target can be easily measured, and Performed with high precision.

According to a fourteenth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the ninth aspect, the two light fluxes are strip-shaped light fluxes, and are mutually linear in a direction orthogonal to the optical axis of the objective optical system. It is characterized by crossing in a shape.

According to this configuration, when the confocal detection method is used, the two luminous fluxes illuminating the object to be measured are strip-like luminous fluxes, respectively, and are linear in the direction orthogonal to the optical axis of the objective optical system. When the surface of the object to be measured further coincides with the position where the position of the intersection of the two light beams and the focal point of the objective optical system coincide with each other, the band-shaped measurement light from the object to be measured is received by the light receiving means. Since the light is received linearly, measurement at a plurality of points is performed simultaneously, so that the time required for measuring the shape of the measurement target is reduced.

According to a fifteenth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the fourteenth aspect, both the intersection line formed by the intersection of the two band-like light beams and the optical axis of the objective optical system are orthogonal. A sample moving means for moving the object to be measured in a moving direction.

According to this configuration, the object to be measured moves in a direction perpendicular to both the intersection line formed by the intersection of the two band-shaped light beams and the optical axis of the objective optical system, and thereby a large surface of the object to be measured is formed. The determination of the position is performed efficiently, and the three-dimensional shape of the measurement target is appropriately measured.

According to a sixteenth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the first aspect, the objective optics of the light beam when the object to be measured is irradiated with at least one of the two light beams. Position determining means for determining the position of the surface of the object to be measured in the optical axis direction, based on the irradiation angle with respect to the optical axis of the system and the position of the photoelectric conversion element that has received the measurement light in the light receiving means. Relative moving means for relatively moving the focal point of the objective optical system relative to the measurement object in the optical axis direction of the objective optical system,
Range setting means for setting a relative movement range of the focal point of the objective optical system by the relative movement means based on the determination result by the position determination means, the relative movement means,
The focus of the objective optical system is moved relatively to the measurement object only in the set relative movement range.

According to this configuration, when the object to be measured is irradiated with at least one of the two light beams, the irradiation angle of the light beam with respect to the optical axis of the objective optical system and the measurement light of the light receiving means are received. The position of the surface of the measurement target in the optical axis direction of the objective optical system is determined by the position determination unit based on the position of the photoelectric conversion element thus obtained, so that the shape of the measurement target is easily measured according to the triangulation method. You. Then, based on the determination result by the position determining means,
The relative movement range of the focus of the objective optical system with respect to the object to be measured by the relative moving means is set, and only the set relative movement range moves the focus relative to the object to be measured. As a result, the time required for measurement is reduced while performing highly accurate shape measurement.

The invention according to claim 17 is characterized in that the first measuring means for measuring first position data relating to the surface position of the object to be measured, and the second measuring means for measuring second position data relating to the surface position of the measuring object. Measuring area determining means for determining a measuring area based on the first position data obtained by the first measuring means; and determining the first position data using the first measuring means, and then determining the measuring area. Measurement control means for obtaining the second position data using the second measurement means within the measurement area determined by the means.

According to this structure, the first position data relating to the surface position of the object to be measured is obtained by the first measuring means,
The measurement area is determined by the measurement area determining means based on the obtained first position data, and the second measurement area is determined within the determined measurement area.
The second position data is obtained by the measuring means. First, the measurement area is roughly determined based on the position data obtained by the first measurement means, and then the accurate surface position of the measurement target is calculated within the measurement area based on the position data obtained by the second measurement means. Therefore, it is possible to suppress the increase in the measurement time while performing the measurement with high accuracy, and to efficiently obtain the three-dimensional shape of the measurement target.

The invention of claim 18 is the three-dimensional shape measuring device according to claim 17, wherein the measurement accuracy of the first position data measured by the first measuring means is the second position data.
It is characterized in that the measurement accuracy is lower than the measurement accuracy of the second position data measured by the measurement means.

According to this configuration, since the first position data is for roughly determining the measurement area, by making the measurement accuracy lower than the measurement accuracy of the second position data,
The measurement area can be determined quickly, and the increase in the measurement time can be further suppressed.

According to a nineteenth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the seventeenth aspect, the first measuring means and the second measuring means respectively determine a focal point of the objective lens and an object to be measured. It measures the surface position of the measurement target by relatively moving in the direction of the optical axis,
The objective lens is shared by the first measuring means and the second measuring means.

According to this configuration, since the objective lens is shared by the first measuring means and the second measuring means, the number of parts can be reduced and the size of the apparatus can be reduced.

According to a twentieth aspect of the present invention, in the three-dimensional shape measuring apparatus according to the seventeenth aspect, the first measuring means measures the surface position of the object to be measured by triangulation. The means is characterized in that the surface position of the object to be measured is measured by moving the focal point of the object lens relative to the object to be measured in the optical axis direction of the object lens.

According to this configuration, since the surface position of the object to be measured is measured by the triangulation method using the first measuring means, the first position data is roughly obtained. On the other hand, since the second measuring means moves the focal point of the objective lens relative to the measurement target in the optical axis direction of the objective lens and measures the surface position of the measurement target, the second position data is high. It is required with precision. The second position data is measured in a measurement area determined based on the first position data.
That is, the relative movement of the focus of the objective lens with respect to the measurement target is performed within the determined measurement area. Therefore, the second
An increase in the measurement time of the position data is suppressed.

According to a twenty-first aspect of the present invention, there is provided the three-dimensional shape measuring apparatus according to the seventeenth aspect, further comprising a coordinate conversion means, wherein the first measurement means and the second measurement means are based on mutually different coordinate systems. Measuring the surface position of the object to be measured, wherein the coordinate conversion means comprises:
The first position data measured by the measuring means is converted into data based on the coordinate system of the second measuring means, and the measuring area determining means is converted into data based on the coordinate system of the second measuring means. The measurement area is determined based on the first position data.

According to this configuration, the first measuring means and the second measuring means are arranged at positions different from each other with respect to the object to be measured, for example, so that the first and second measuring means use different coordinate systems. The surface position of the measurement object is measured based on the measurement. Then, the first position data measured by the first measuring means is converted into data based on the coordinate system of the second measuring means, and the first position data converted into data based on the coordinate system of the second measuring means is converted into the first position data. A measurement area is determined based on the measurement area, and second position data is measured by the second measurement means in the measurement area. Therefore, the position of the first and second measuring means with respect to the object to be measured can be freely set, and the degree of freedom in designing the measuring device increases.

According to a twenty-second aspect of the present invention, the position data relating to the surface position of the object to be measured is measured with a first accuracy, and a measurement region is determined based on the measured position data. The method is characterized in that the position data is measured with a second accuracy higher than the first accuracy, and the three-dimensional shape of the measurement object is obtained using the position data measured with the second accuracy.

According to this method, the position data relating to the surface position of the measurement object is measured with the first accuracy, the measurement area is determined based on the measured position data, and the measurement object is determined within the determined measurement area. Is measured with a second accuracy higher than the first accuracy. That is, the position data relating to the surface position of the measurement target is measured roughly first, the measurement region is determined based on the position data, and the position data relating to the surface position of the measurement target is measured with high accuracy within this measurement region. Becomes Therefore, since the measurement with the second accuracy higher than the first accuracy is performed only in the measurement area,
The time required for measurement is reduced while performing high-precision measurement.

[0064]

FIG. 11 is a perspective view showing the appearance of one embodiment of a three-dimensional shape measuring apparatus according to the present invention.

The three-dimensional shape measuring apparatus 1 has a keyboard 2 for inputting a measurement start instruction and setting data.
And a display unit 3 for displaying measurement results and the like, a control unit 4 for performing overall control of the apparatus, and a measurement unit 5. The function of the control unit 4 will be further described later.

The measuring section 5 includes a sample table 11 on which the object 6 to be measured is mounted, and a Y-axis driving column 13 for supporting the camera section 12 so as to be movable in the Y-axis direction. It is configured. The sample stage 11 is configured to be movable in the X-axis direction and the Z-axis direction with respect to the base 14 as shown by an arrow in the figure, and is configured to be rotatable around the center (θ direction). I have. Note that the three-dimensional coordinate system (X, Y,
Z) is set as shown in FIG.

FIG. 1 is a diagram showing the internal configuration of the camera unit 12,
FIG. 2 is a block diagram showing an electrical configuration of the three-dimensional shape measuring device.

As shown in FIG. 1, the camera section 12 includes an illumination means 20, an objective optical system 30, and a light receiving means 40.

The illuminating means 20 includes a laser light source 21 for emitting laser light, a collimator lens 23 for collimating the laser light into a parallel light flux 22,
Half mirror 2 branched into two parallel light beams 22a and 22b
4a and a parallel light beam 22b that reflects the parallel light beam 22a.
A reflecting mirror 24b for making the light beams parallel with each other, and parallel light beams 22a and 22b
With a very small thickness (for example, 10 μm in this embodiment)
m), the Galilean optical systems 26a and 26b for converting into a strip-shaped collimated light flux (hereinafter, simply referred to as "strip-shaped light flux") 25a and 25b, and the irradiation directions are changed by reflecting the strip-shaped light fluxes 25a and 25b, respectively. It is composed of galvanomirrors 27a and 27b.

The galvanometer mirrors 27a and 27b are configured so that their angles can be changed with high precision in the microradian order individually or individually in conjunction with each other.
By changing the angle in conjunction therewith, the belt-like light beams 25a, 25
The position of the intersection 28 of 5b is movable left and right in FIG. 1 on the optical axis L1 of the objective optical system 30. In this embodiment, the position of the intersection 28 between the belt-like light beams 25a and 25b is usually configured to coincide with the focal point of the objective lens group 31.

The objective optical system 30 includes an objective lens group 31 for condensing measurement light from the measurement target 6 illuminated by the belt-like light beams 25a and 25b of the illumination means 20, and an objective lens group 3
A telecentric optical system is constituted by a reflecting mirror 32 that reflects the light passing through 1. The objective lens group 31 has a zoom function, and its focal point is movable.

Further, as shown in FIG. 1, the camera section 12 sets the opening angle of the objective optical system 30 (objective lens group 31) to θ, the irradiation angle of the belt-like light beam 25a with respect to the optical axis L1 to α,
Assuming that the irradiation angle of the belt-like light beam 25b with respect to the optical axis L1 is β, θ <α and θ <β are established.
That is, the aperture angle θ of the objective optical system 30 is
a, 25b are configured to be smaller than the irradiation angles α, β.

The light receiving means 40 is constituted by arranging a plurality of photoelectric conversion elements 41 (see FIG. 2) such as CCDs or photodiodes two-dimensionally. One row of the photoelectric conversion elements 41 (FIG. 2) is arranged at a position conjugate with the focal point of the objective optical system 30.

In FIG. 2, a light emitting circuit 51 drives the laser light source 21, a camera main body driving unit 52 drives the Y-axis driving column 13, and a sample stage driving unit 53 drives the sample stage 11. It is.

The mirror driving unit 54 is a galvanomirror 27
The zoom drive unit 55 drives the objective lens group 31 to move the focal point in the Z-axis direction by driving the a and 27b in conjunction with each other or individually to change the angle. .

The control unit 4 includes a RAM 61 and a ROM 62
And a CPU 63. The RAM 61 temporarily stores data, and the ROM 62 stores a control program of the CPU 63 including data set in advance.

The CPU 63 controls the entire apparatus. As will be described later, first, the CPU 63 performs a prescan for measuring the approximate shape of the measurement object 6 by the triangulation method using the strip light beam 25a or the strip light beam 25b. Next, the focus of the objective optical system 30 is moved to perform a focus scan for precisely measuring the shape of the measurement target 6, and has the following functions.

(1) Laser light source 21 via light emitting circuit 51
Function as light emission control means 71 for controlling light emission of the light emitting device.

(2) Function as an optical system position control means 72 for controlling the position of the camera section 12 in the Y-axis direction via the camera body drive section 52.

(3) Measurement target 6 via sample stage drive unit 53
Function as sample position control means 73 for controlling the position in the X-axis direction and the Z-axis direction and the rotation angle φ.

(4) Function as mirror control means 74 for individually controlling the angles of the galvanometer mirrors 27a and 27b via the mirror drive unit 54.

(5) Zoom control means 7 for moving the focal point of the objective lens group 31 in the Z-axis direction via the zoom drive unit 55
Function as 5.

(6) The angle of the galvanomirrors 27a and 27b is changed by the mirror drive unit 54 in conjunction with the zoom drive unit 55 to make the position of the intersection 28 of the belt-like light beams 25a and 25b coincide with the focal point of the objective lens group 31. Function as the intersection position control means 76 for controlling the operation.

(7) A signal for detecting the level of an electric signal output from the photoelectric conversion element 41 of the light receiving means 40 that has received the measurement light from the measurement target 6 when the measurement target 6 is irradiated with the belt-like light beams 25a and 25b. Function as level detecting means 77.

(8) Strip light beam 25a or strip light beam 25b
Is measured in the direction of the optical axis L1 based on the angle of the light beam with respect to the optical axis L1 of the objective optical system 30 and the position of the photoelectric conversion element 41 that has received the measurement light from the measurement object 6 when the measurement object 6 is irradiated with the light beam. A function as position determining means 78 for determining the position of the surface of the object 6 by triangulation. The operation by this function will be described later.

(9) Intersection 28 of strip-like light beams 25a and 25b
When the position of and the focal point of the objective lens group 31 are moved in the direction of the optical axis L1, the level of the electric signal output from the photoelectric conversion element 41 of the light receiving unit 40 that has received the measurement light from the measurement target 6 is maximized. Function as focus determination means 79 for determining the position of the intersection 28 when The operation by this function will be described later.

(10) A range for setting the moving range in the direction of the optical axis L1 of the position of the intersection 28 of the belt-like light beams 25a and 25b when making the determination by the focus determining means 79 based on the determination result by the position determining means 78. Function as setting means 80. The operation by this function will be described later.

As shown by a dashed line in FIG. 2, a gear mechanism 56 for connecting the zoom drive unit 55 and the mirror drive unit 54 only when the zoom drive unit 55 is driven is provided. When the mirror moves, the mirror driving unit 5
4 interlocks with each other and intersects 2 between two belt-like light beams 25a and 25b.
The position 8 may also be configured to move in accordance with the focal point. In this case, the function of the CPU 63 as the intersection position control means 76 becomes unnecessary.

In the above configuration, the sample stage driving section 53 and the sample stage 11 constitute a relative moving means. The sample stage drive unit 53 and the sample stage 11 constitute a sample moving unit. The mirror driving unit 54 and the galvanometer mirrors 27a and 27b constitute a relative moving unit.
Further, the mirror driving unit 54 and the galvanometer mirror 27a,
27b constitutes the intersection position moving means. The zoom drive unit 55 constitutes a zoom unit (focus moving unit).

In the focus scan, the objective optical system 3
When the focal point of 0 is moved, the two luminous fluxes 25a,
Since the position of the intersection 28b of the lens 25b also moves so as to coincide with the focal point thereof, the following description will be made of the "objective optical system 3".
When the “scan of the focal point of 0” is referred to, “the two band-like light beams 25
Scanning the intersection 28 between a and 25b ".

Next, the operation of the optical system having the structure shown in FIGS. 1 and 2 will be described.

The laser light emitted from the laser light source 21 is collimated into a parallel light flux 22 and branched in two directions by a half mirror 24a.
a and 26b are converted into belt-like luminous fluxes 25a and 25b,
The light is guided to the galvanomirrors 27a and 27b. When the angles of the galvanometer mirrors 27a and 27b are individually changed, the belt-like light beams 25a and 25b with respect to the optical axis L1 of the objective optical system 30 are provided.
Are changed and the angles of the galvanometer mirrors 27a and 27b are changed in conjunction with each other, the two band-shaped light beams 25a and
The position of the intersection 28 of 25b is moved on the optical axis L1.
Then, the measurement light from the measurement target 6 illuminated by the belt-like light beams 25a and 25b enters the light receiving unit 40 via the objective optical system 30.

Here, the opening angle θ of the objective optical system 30 is determined by the irradiation angle α of the belt-like light beams 25a and 25b with respect to the optical axis L1,
Since it is configured to be smaller than β, the specularly reflected light (zero-order light) from the measurement target 6 hardly enters the objective optical system 30, and only the scattered light enters.

This has the same effect as the use of the optical high-pass filter. The low-frequency component in the reflected light from the surface of the measuring object 6 is cut off, and only the light intensity of the high-frequency component is taken into the light receiving means 40. It will be. Thereby, the variation width of the light intensity of the light incident on the light receiving unit 40 due to the difference in the reflection characteristics of the surface properties of the measurement object 6 is narrowed, so that the dynamic range of the photoelectric conversion element 41 is not exceeded. The shape of the measurement target 6 having the surface property can be measured.

Next, the shape measurement operation in the pre-scan will be described with reference to FIGS. FIG. 3 shows two belt-like light beams 25a and 25b for explaining pre-scanning.
FIG. 4 is a perspective view showing the object 6 to be measured, and FIG.

As shown in FIG. 3, the two zonal light beams 25
a and 25b are angles α and β with respect to the optical axis plane LS, respectively.
When the light is projected from two directions toward the measurement object 6 and the measurement object 6 is irradiated by the two band-shaped light beams 25a and 25b, the scattered light 42a, 42b, 42c, 42d, and 42e are observed. Here, as shown in FIG.
Assuming that the position in the two-dimensional light receiving image of the light receiving means 40 corresponding to the intersection 28 between a and 25b is the reference line 43, the position of the reference line 43 (for example, the dimension D in FIG. 4) is known.

For example, on the measuring object 6 shown in FIG.
The coordinates (x, y, z) of the irradiation position A of the belt-like light beam 25b are as follows.
It is required as below. That is, as shown in FIG.
According to the two-dimensional light receiving image observed by the light receiving means 40,
And the coordinates (x₁, Y ₁)
The distance e between the quasi-line 43 and the scattered light A 'is determined. And a strip
Assuming that the z coordinate of the intersection 28 between the light beams 25a and 25b is H, FIG.
As shown in FIG. 3, the irradiation angle of the belt-like light beam 25b is β.
And the coordinates (x, y, z) of the irradiation position A are given by the following equation (1).
Desired.

(X, y, z) = (x ₁ , y ₁ , e · cotβ + H) (1) Then, the sample stage 11 is driven to move the measurement target 6 to the intersection 28
The shape of the measurement target 6 is measured by successively taking in the coordinates of the scattered light observed while moving in the direction orthogonal to the intersection line formed by, that is, in the X-axis direction. Scanning range (in the present embodiment, for example, ±± in the Z-axis direction from the surface of the measurement target 6)
50 μm) is set.

In this pre-scan, when the two band-like light beams 25a and 25b are simultaneously irradiated on the measurement object 6, as shown in FIG. 4, the scattered lights 42a, 42b, 42c and 42
Since d and 42e are observed at the same time, it is necessary to determine from which band light flux the scattered light from the measurement target 6 originated. At this time, the galvanomirrors 27a and 27b
Is changed until the zonal light flux is shaken off from the two-dimensional light-receiving image of the light receiving means 40, and only the scattered light by the other zonal light flux is reflected in the two-dimensional light-receiving image. Can be determined.

The measurement accuracy in this prescan is 2
Angles of the two strip-shaped light beams 25a and 25b,
Although it depends on the magnification of the pixel and the size of the pixel of the photoelectric conversion element 41 (FIG. 2), the present embodiment is configured so that a measurement accuracy of, for example, several tens to hundreds of μm can be obtained.

The measurement accuracy by the prescan, that is, the interval between the measurement points for obtaining the measurement data may be any value as long as it is not coarser than the scan distance by the focus scan. this is,
This is because the prescan is a measurement for determining the scanning range by the focus scan, and is not a measurement for obtaining detailed shape data. Thus, the coarse measurement by the prescan is performed in a shorter time than the detailed measurement by the focus scan.

According to the prescan, the light receiving means 40-2
By changing the angles of the galvanometer mirrors 27a and 27b so that the measurement target 6 can be scanned in the two-dimensional light reception image, the position of the surface of the measurement target 6 can be obtained.
It is possible to set the scanning range of the focal point including the surface of the measurement target 6 without fail.

Further, since the two belt-like light beams 25a and 25b are projected toward the measurement target 6 from two directions, "shaking" due to the shape of the measurement target 6 can be reduced.
In other words, the “beam” is applied to one of the belt-like light beams 25a and 25b.
Even if the light beam is generated, the shape of the measurement target 6 can be measured unless the other band-shaped light beam is "blurred", so that the blind spot of the shape measurement can be reduced.

In general, since the measurement target 6 has various side shapes, it is difficult to measure the entire shape by scanning from one direction. It is possible to rotate in the direction
It is possible to measure the side surface shape from various angles, reducing the blind spot of the measurement.

In addition, the larger the irradiation angles α and β of the belt-like light beams 25a and 25b, the more accurate the measurement can be made, and the smaller the pixel of the photoelectric conversion element 41 of the light receiving means 40, the more accurate the measurement. As a result, the scanning range can be reduced, so that the measurement time in the focus scan can be reduced.

When the measuring object 6 is located outside the visual field range of the camera section 12, the shape of the measuring object 6 is measured by sequentially moving the sample stage 11 in the X-axis direction and the Z-axis direction. be able to.

Next, the measurement operation in the focus scan will be described with reference to FIGS.

In FIG. 1, in the focus scan, two band-like luminous fluxes 25 are set within a scan range set by the pre-scan.
The positions of the intersections 28a and 25b and the focal point of the objective optical system 30 are sequentially moved by a predetermined minute distance in the cross-sectional direction of the measurement target 6, that is, in the direction of the optical axis L1 (Z-axis direction), and the measurement at each position Light scattered from the surface of the target 6 is received by the light receiving means 40.

FIG. 5A shows a state in which two belt-like light beams 25a and 25b collimated to a thickness on the order of μm are projected from two directions by galvanometer mirrors 27a and 27b (FIG. 1) and intersect at an intersection 28. Is shown. FIG. 6 is a diagram showing the light intensity distribution near the intersection 28.
It can be seen that the light intensity is maximized at the intersection 28 between the two belt-like light beams 25a, 25b.

The position of the intersection 28 can be arbitrarily moved in a three-dimensional space by controlling the angles of the galvanometer mirrors 27a and 27b with a precision of the order of microradians. In this case, since the aberration does not change even if the position of the intersection 28 is changed, the light intensity distribution does not change.

Therefore, as shown in FIG. 5B, in a conventional confocal optical system in which the position of the maximum light intensity is formed by image formation, when a zoom lens is used, when the position of the focal point changes, the aberration characteristic is changed. Changes, and the light intensity distribution when condensed changes.

On the other hand, in the present embodiment, the measurement target 6 is irradiated with the two band-like light beams 25a and 25b having the same light intensity distribution at all times, and the measurement light from the measurement target 6 is used only once. Since the light passes through the optical system 30, the total aberration can be reduced as compared with the related art.
Thereby, measurement accuracy can be improved.

As described above, in the present embodiment, the measurement target 6
Illumination means 20 for irradiating a light beam and objective optical system 30 for receiving measurement light from measurement object 6 are separated,
A pseudo-confocal optical system that performs the same function as a conventional confocal optical system is configured.

Returning to FIG. 1, in the focus scan, among the photoelectric conversion elements 41 (FIG. 2) of the light receiving means 40, the intersection line formed by the intersection 28 of the two band-like light beams 25a and 25b is parallel to the intersection line. Only electric signals output from one row of photoelectric conversion elements 41 (for example, a row corresponding to the reference line 43 shown in FIG. 4) arranged at a position conjugate with the focal point of the objective optical system 30 are used for measurement as measurement data. . Thereby, the slit is arranged immediately before the light receiving means, and the same effect as the confocal effect in which the scattered light of the maximum intensity is incident on the light receiving means when the focus coincides with the surface of the object to be measured can be obtained.

The electric signals of one row of photoelectric conversion elements 41 output from the light receiving means 40 are sequentially A / D converted and stored in the RAM 61. When the measurement of the set scanning range is completed, a curve representing the relationship between the focal point and the light intensity is obtained from the data stored in the RAM 61, and the position of the focal point can be known from the position of the maximum value. The position of the surface of the object 6 will be indicated. When the measurement of one cross section is completed, the measurement target 6 is moved by a predetermined minute distance in the X-axis direction, and the measurement of the next one cross section is performed similarly.

FIG. 7 shows that the position of the intersection 28 is from −90 μm to 90 μm in the direction of the optical axis L1 (Z-axis direction) from the surface of the object 6 to be measured.
FIG. 10 is a diagram showing a result of simulating a change in light intensity distribution in a width direction of a light beam observed when scanning is performed over a range of 0.1, where the numerical aperture of the objective optical system 30 is 0.1, and the thickness of the band-like light beams 25a and 25b is 10 μm, and the light intensity is normalized to 1. FIG. 8 shows the photoelectric conversion element 4 under the same conditions as FIG.
FIG. 9 is a diagram showing a result of simulating a change in a light intensity signal with respect to a defocus amount from the surface of a measurement target 6 observed when a CCD pixel having a width of 10 μm is used as 1.

As shown in FIGS. 7 and 8, when the collimated belt-like light beams 25a and 25b cross each other, the intersection 28
Acts as a focal point in a pseudo manner, and can obtain a light intensity signal change due to a focal point shift similarly to the conventional confocal optical system,
It can be seen that highly accurate shape measurement is possible.

As described above, in the focus scan, the measurement is performed only in the scan range set based on the measurement result of the pre-scan, so that the measurement time can be shortened and the signal from the photoelectric conversion element 41 can be reduced. The capacity of the RAM 61 required to store the measurement data can be reduced.

In the present embodiment, the measurement accuracy in the focus scan is configured such that a measurement accuracy of, for example, about 0.5 to 10 μm is obtained.

Next, referring to FIG. 1, FIGS.
The procedure of the measurement operation by the present apparatus will be described with reference to the flowchart of FIG.

In the flowcharts of FIG. 9 and FIG.
# 100 to # 210 indicate a pre-scanning procedure, and
Reference numerals 220 to # 320 denote a focus scanning procedure.

First, the two belt-like light beams 25a and 25b are irradiated (# 100), and the light intensity data by the measuring light from the measuring object 6 is taken in through the light receiving means 40 and the RAM is used.
61 (# 110), and 2
The contact positions of the band-like light beams 25a and 25b in the two-dimensional light receiving image are extracted (# 120), and the surface position of the measurement target 6 is specified from the contact positions by calculation of triangulation (# 120).
130).

Next, it is determined whether or not the measurement in the X-axis direction has been completed (# 140). If the measurement has not been completed yet (# 140)
(NO at 140), the angles of the galvanometer mirrors 27a and 27b are changed by a predetermined angle (# 150), and the process returns to # 100.

On the other hand, when the measurement in the X-axis direction is completed (# 1)
It is determined whether the measurement in the Y-axis direction has been completed or not (# 160). The measurement object 6 is a belt-like light beam 25a,
If the width in the Y-axis direction is larger than the width dimension of 25b and the measurement in the Y-axis direction has not been completed yet (NO in # 160), the camera unit 12 is moved to the unmeasured area in the Y-axis direction (# 1).
70), returning to # 100.

On the other hand, when the measurement in the Y-axis direction is completed (# 1)
(YES at 60), it is determined whether or not the measurement of the side surface of the measurement target 6 has been completed (# 180). If the measurement has not been completed yet (NO at # 180), the measurement target 6 is rotated and moved by a predetermined angle. (# 190), and return to # 100.

On the other hand, if the measurement of the side surface of the measuring object 6 has been completed (YES in # 180), then a three-dimensional shape of the measuring object 6 is created by performing coordinate transformation and the like, The approximate shape is measured (#
200). Next, the scanning range of the focal point in the focal point scanning is set using the measurement result (# 210).

As described above, in the prescan operation, high-speed measurement is performed by triangulation with relatively coarse measurement accuracy.

Following the pre-scan, a focus scan is performed. First, the focal point is set to Z only in the set scanning range.
Scanning is performed in the axial direction, light intensity data at each position is captured and stored in the RAM 61 (# 220), and then the maximum value of the light intensity data is extracted to specify the surface position of the measurement target 6 (# 230). ).

Next, it is determined whether or not the measurement in the X-axis direction has been completed (# 240). If the measurement has not been completed yet (# 240)
The measurement target 6 is moved in the X-axis direction by a predetermined distance (# 250), and it is determined whether or not the scanning range set at this X coordinate is within the focus movement range of the objective lens group 31. Then, if it is within the focus movement range (YES in # 260), the process returns to # 220. On the other hand, if the scanning range is not within the focus moving range (NO in # 260),
The measurement target 6 is moved in the Z-axis direction until it is within the focus movement range (# 270), and the process returns to # 220.

On the other hand, if the measurement in the X-axis direction has been completed (YES in # 240), it is determined whether the measurement in the Y-axis direction has been completed (# 280), and if not completed (# 240). (NO in 280), the camera section 12 is moved to the unmeasured area in the Y-axis direction (# 290), and the process returns to # 220.

On the other hand, if the measurement in the Y-axis direction has been completed (YES in # 280), it is determined whether or not the measurement on the side surface of measurement target 6 has been completed (# 300). (NO in # 300), the measurement target 6 is rotated by a predetermined angle (# 310), and the process returns to # 220.

On the other hand, it is determined whether or not the measurement of the side surface of the measurement target 6 has been completed (# 300), and the measurement data is connected by coordinate transformation or the like to create a three-dimensional shape (# 310).

As described above, in the focus scan operation, the measurement range obtained by the prescan is measured by a focus scan different from that at the time of the prescan. Therefore, more accurate measurement data can be obtained, and the measurement time can be shortened because only the necessary area is precisely measured.

Note that the present invention is not limited to the above embodiment, but can adopt the following modified embodiments.

(1) In the above embodiment, as shown in FIG. 1, the laser beam from the laser light source 21 is separated into two beams by using the half mirror 24a, but the invention is not limited to this. Alternatively, two laser light sources may be used. In this case, the two laser light sources are turned on and off alternately, and the light intensity data from the light receiving means 40 is taken in synchronism with the blinking, so that the light intensity data in the two-dimensional light-receiving image becomes two band-like light beams 25a and 25
It is possible to determine which one of b is caused by the band light beam.

(2) In the above embodiment, the galvanometer mirrors 27a and 27b are used during the pre-scan and the focus scan.
However, the measurement is not limited to this, and the measurement can be similarly performed by fixing the galvanometer mirrors 27a and 27b and scanning the measurement target 6 in the Z-axis direction.

(3) FIG. 12 is a view showing a modification of the camera section 12. As shown in FIG. 12, the same components as those in FIG. 1 are denoted by the same reference numerals.

In the above embodiment, as shown in FIG. 1, the same light receiving means 4 is used for the pre-scan and the focus scan.
Although the light is received at 0, in this modified embodiment, the light is received by different light receiving means.

That is, as shown in FIG. 12, a half mirror 33 is provided between the light receiving means 40 and the reflecting mirror 32, and a light receiving means 42 for receiving the light reflected by the half mirror 33 is provided. ing. Then, at the time of prescan, measurement is performed using the light reception signal from the light receiving means 40, and at the time of focus scanning, measurement is performed using the light reception signal from the light receiving means 42.

Since the light receiving means 40 is used for pre-scan for determining the measurement area of the focus scan, an area sensor having a relatively low resolution may be employed as the light receiving means 40. For example, by using a camera adopted in a commercially available video camera, the light receiving unit 40 can be configured at low cost.

On the other hand, since the light receiving means 42 is used for the focus scan which is the main scan,
A high-resolution line sensor is used. Then, the line sensor is disposed at a position conjugate with the focal point of the objective optical system 30.

In the above embodiment, since the same light receiving means 40 is used for the pre-scan and the focus scan, it is necessary to use a high-resolution area sensor in order to obtain high-precision data in the focus scan. In addition, there is a possibility that the cost for the device configuration may increase. On the other hand, according to this modification, the light receiving means 40 and 42 can be configured according to the measurement accuracy, so that the device can be configured at a lower cost than in the above embodiment. Can be.

(4) FIG. 13 is a view showing another modification of the camera section 12. As shown in FIG. 13, the same components as those in FIG. 1 are denoted by the same reference numerals.

In this embodiment, the Galileo optical system 26 shown in FIG.
Optical systems 26c and 26d having very small numerical apertures are provided instead of the optical systems 26a and 26b.

The optical systems 26c and 26d respectively convert the collimated light beams 22a and 22b into a band-like light beam 25 converged to a very small thickness (in the present modified example, for example, over ten μm).
c and 25d, and are guided to the galvanometer mirrors 27a and 27b. The optical systems 26c and 26d are set so that the most focused positions of the strip-shaped light beams 25c and 25d are in the vicinity of the intersection 28.

According to this modification, even when it is difficult to generate a collimated belt-like light beam, the distance from the galvanomirrors 27a, 27b to the object 6 is sufficiently longer than the scanning range of the intersection 28. With such a configuration, it is possible to perform measurement with the same accuracy as in the case of using the collimated zonal light beam.

(5) FIG. 14 is a view showing another modification of the camera section 12. As shown in FIG. 14, the same components as those in FIG. 13 are denoted by the same reference numerals.

In the embodiments shown in FIGS. 1 and 13, the optical system for performing the prescan and the optical system for performing the focus scan are constituted by a common optical system. In the embodiment shown in FIG. It consists of a system. That is, the camera unit 12 shown in FIG. 14 includes a triangulation measurement device 90 provided outside the objective optical system 30.
Includes an illuminating unit 91 and a light receiving unit 92.

The illuminating means 91 outputs band-like slit light, and illuminates the measuring object 6 with the slit light. The light receiving unit 92 receives the reflected light from the measurement target 6 illuminated by the illumination unit 91, and outputs an electric signal corresponding to the intensity of the received light. The light receiving means 92 is constituted by an area sensor in which photoelectric conversion elements are two-dimensionally arranged.

In this embodiment, a light receiving means 43 is provided in place of the light receiving means 40. This light receiving means 43
It is constituted by a line sensor in which photoelectric conversion elements are arranged in a line, and this line sensor is arranged at a position conjugate with the focal point of the objective optical system 30.

The pixel density of the line sensor of the light receiving means 43 is higher than the pixel density of the area sensor of the light receiving means 92. This is because the measurement by the light receiving means 92 is a coarse measurement for determining the scanning range by the focus scan, and the measurement by the light receiving means 43 is a precise measurement for obtaining the shape of the measurement target 6 by the focus scan. is there.

In the embodiment shown in FIG. 14, the measurement procedure can be performed in the same manner as the procedure shown in FIGS. However, in this embodiment, since the measurement system for the focus scan and the triangulation measurement device 90 are arranged at different positions with respect to the measurement target 6, they perform measurement with reference to different coordinate systems. That is, as shown in FIG. 14, the measurement system of the focus scan performs the measurement based on the coordinate system (X, Y, Z), whereas the triangulation measuring device 90 uses the coordinate system (Xp, Y).
(p, Zp) is measured. Therefore, it is necessary to perform coordinate conversion before performing the operation of step # 210 in FIG. This coordinate conversion is performed by the CPU 63 (FIG. 2).

When a point Vp represented in the coordinate system (Xp, Yp, Zp) is represented as a point V in the coordinate system (X, Y, Z), there is a relation V = T · The relationship of the coordinate transformation of Vp (A) is established.

Here, Vp and V are respectively

[0155]

(Equation 1)

[0156]

(Equation 2)

And a 4 × 1 vector.

The coordinate transformation matrix T is obtained by using a rotation matrix R representing the inclination between the coordinate systems and a translation row H representing the displacement of the origin.

[0159]

(Equation 3)

Are represented as follows. Where R is a 3 × 3 matrix,
H is a 4 × 1 vector and T is a 4 × 4 matrix.

In the above equations (1) and (2), the points Vp,
The first three elements represent the actual coordinates of V, and 1 is the element needed to add the translation value.

After the measurement up to the step # 200 in FIG. 9 is performed by the triangulation measuring device 90, the coordinates of each measured point are calculated using the coordinate transformation matrix T in the above equation.
It is converted into a focal scan coordinate system according to (A). Then, in step # 210 of FIG. 9, the scanning range of the focal point scanning is set in the positive and negative directions with respect to the Z coordinate of each coordinate-converted point. For example, when the scanning width is 1 mm and the Z coordinate converted is 100 mm, the scanning range is 99.5 to 100.5 mm. Then, similarly to the above embodiment, the measurement is performed according to the procedure of FIG.

(6) In the above embodiment, the two band-shaped light beams 25a and 25b are used. However, the present invention is not limited to this. You may make it shake in a direction. In this case, three or more thin light beams may be used.

[0164]

As described above, according to the first aspect of the present invention, the object to be measured is illuminated by the illuminating means from two directions different from each other and illuminated by two light beams intersecting at a predetermined position. The measurement light from the object to be measured is captured by an objective optical system, and the captured measurement light is received by a plurality of photoelectric conversion elements and an electric signal corresponding to the received light intensity is output. The system is separated, and the two light beams pass through the objective optical system only once, so that the influence of the aberration of the objective optical system can be reduced.

According to the second aspect of the present invention, the two light beams illuminating the object to be measured are each a collimated light beam, so that the intensity of the measurement light received by the light receiving means is stabilized. And the measurement accuracy can be improved.

According to the third aspect of the present invention, the two luminous fluxes for illuminating the object to be measured are luminous fluxes which are focused in the vicinity of the predetermined position crossing each other.
When the measurement target is irradiated near the predetermined position, the intensity of the measurement light received by the light receiving unit becomes high, and the measurement accuracy can be improved.

According to the fourth aspect of the present invention, since the light receiving means comprises a plurality of photoelectric conversion elements arranged two-dimensionally, two light beams illuminating the object to be measured spread. If it has, the plurality of photoelectric conversion elements receive light, and the time required for shape measurement of the measurement target can be reduced.

Further, according to the invention of claim 5, when the object to be measured is irradiated with at least one of the two light beams, the irradiation angle of the light beam with respect to the optical axis of the objective optical system, and the light receiving means The position of the surface of the measurement target in the optical axis direction of the objective optical system is determined based on the position of the photoelectric conversion element that has received the measurement light, and the shape of the measurement target is easily measured according to the triangulation method. be able to.

According to the sixth aspect of the present invention, the position of the intersection where two light beams intersect is moved in a predetermined direction. Even in a difficult case, the surface of the object to be measured is quickly covered with the two light beams, and the shape of the object to be measured can be suitably measured.

According to the seventh aspect of the present invention, since the object to be measured is moved in a predetermined direction, the surface of the object to be measured can be easily covered by two light beams, and the shape of the object to be measured can be improved. Measurement can be suitably performed.

According to the eighth aspect of the present invention, the two luminous fluxes illuminating the object to be measured are each a band-shaped light beam intersecting linearly with each other, thereby receiving the band-shaped measurement light from the object to be measured. By receiving light two-dimensionally by the means, the time required for measuring the shape of the measurement object can be reduced.

Further, according to the ninth aspect of the present invention, since the position of the intersection of the two light beams and the focal point of the objective optical system are configured to coincide with each other, the object to be measured is further located at the coincident position. When the surfaces match, the level of the measurement light taken into the objective optical system becomes maximum, and the surface position of the measurement target can be easily determined.

According to the tenth aspect of the present invention, the aperture angle of the objective optical system is configured to be smaller than the irradiation angle of the two light beams with respect to the optical axis of the objective optical system.
The specularly reflected light from the object to be measured hardly enters the objective optical system, and only the scattered light enters, thereby making it possible to narrow the variation width of the light intensity of the light incident on the light receiving means. An electric signal corresponding to the received light intensity can be suitably output from the means.

According to the eleventh aspect, the light receiving means includes a row of photoelectric conversion elements arranged at a position conjugate with the focal point of the objective optical system with respect to the objective optical system.
Using the level of the electric signal output from the one row of photoelectric conversion elements arranged at the conjugate position, the position of the intersection of the two light fluxes and the position of the focal point of the objective optical system coincide with each other, and When the surfaces coincide with each other, the level of the electric signal output from the photoelectric conversion element becomes maximum, and the surface position of the measurement target can be easily determined with high accuracy.

According to the twelfth aspect of the present invention, the focal point of the objective optical system is moved in the optical axis direction, and the position of the focal point when the electric signals output from the plurality of photoelectric conversion elements are maximum is measured. Since the position is determined as the surface position, the position of the intersection of the two light beams and the focal point of the objective optical system are configured to match, so that the focal point of the objective optical system and the surface of the measurement target match. Then, the level of the measurement light taken into the objective optical system is maximized, so that the three-dimensional shape of the measurement target can be measured easily and with high accuracy.

According to the thirteenth aspect of the present invention, the measuring object is moved in the optical axis direction, and the measuring object is moved based on the moving amount of the measuring object when the electric signals output from the plurality of photoelectric conversion elements are maximum. Since the surface position is determined,
Since the configuration is such that the position of the intersection of the two light beams and the focal point of the objective optical system match, when the focal point of the objective optical system and the surface of the measurement object match, the measurement light taken into the objective optical system The level is maximized, so that the three-dimensional shape of the measurement object can be measured easily and with high accuracy.

According to the fourteenth aspect of the present invention, the two luminous fluxes illuminating the object to be measured are strip-shaped luminous fluxes, and linearly cross each other in a direction orthogonal to the optical axis of the objective optical system. Thus, when the position of the intersection of the two light beams and the position of the focal point of the objective optical system coincide with each other and the surface of the measurement object coincides, the band-like measurement light from the measurement object is linearly received by the light receiving means. By doing so, measurement at a plurality of points is performed simultaneously, so that the time required for measuring the shape of the measurement target can be reduced.

According to the fifteenth aspect of the present invention, the measurement object is moved in a direction perpendicular to both the intersection line formed by the intersection of the two band-shaped light beams and the optical axis of the objective optical system. It is possible to efficiently determine the position of the wide surface of the object, and it is possible to suitably measure the three-dimensional shape of the measurement object.

According to the sixteenth aspect of the present invention, when the object to be measured is irradiated with at least one of the two light beams, the irradiation angle of the light beam with respect to the optical axis of the objective optical system and the light receiving means The position of the surface of the object to be measured in the direction of the optical axis of the objective optical system is determined by the position determining means based on the position of the photoelectric conversion element that has received the measuring light, and the objective by the relative moving means is determined based on the determination result. Since the relative movement range of the focus of the optical system is set, and the focus moves relative to the measurement target only in the set relative movement range, high-precision shape measurement is performed only in the relative movement range. The measurement time can be shortened while performing highly accurate shape measurement.

According to the seventeenth aspect of the present invention, first position data relating to the surface position of the object to be measured is obtained by the first measurement means, and the measurement area is determined by the measurement area determination means based on the obtained first position data. Since the second position data is obtained by the second measuring means in the determined measurement area, it is possible to efficiently measure the three-dimensional shape of the measurement target.

According to the eighteenth aspect, the measurement accuracy of the first position data measured by the first measuring means is:
Since the measurement accuracy of the second position data measured by the second measurement means is lower, the measurement region is roughly determined by the first position data, and the second position data is obtained with high accuracy within the measurement region. , The time required for measurement can be reduced.

According to the nineteenth aspect of the present invention, the objective lens is shared by the first measuring means and the second measuring means, so that the number of parts can be reduced and the size of the apparatus can be reduced.

According to the twentieth aspect, the first measuring means measures the surface position of the object to be measured by triangulation, and the second measuring means sets the focus of the objective lens on the object to be measured. Since the surface position of the object to be measured is measured by relatively moving the objective lens in the optical axis direction, the first position data is roughly obtained by triangulation and determined based on the first position data. Since the relative position of the focal point of the objective lens is moved within the measurement area to obtain the second position data with high accuracy, it is possible to suppress an increase in the measurement time of the second position data.

According to the twenty-first aspect, the first measuring means and the second measuring means measure the surface position of the object to be measured based on mutually different coordinate systems.
The first position data measured by the first measurement means is converted into data based on the coordinate system of the second measurement means, and the measurement area is determined based on the first position data converted into data based on the coordinate system of the second measurement means. Is determined, the setting of the arrangement position of the first and second measuring means with respect to the measurement object becomes free, and the degree of freedom in designing the measuring device can be increased.

According to the twenty-second aspect of the present invention, the position data relating to the surface position of the object to be measured is measured with the first accuracy, and the measurement area is determined based on the measured position data.
In the determined measurement area, the position data is measured with a second accuracy higher than the first accuracy, and the three-dimensional shape of the measurement object is obtained using the position data measured with the second accuracy. As a result, the measurement with the second accuracy higher than the first accuracy is performed only in the measurement area, and the time required for the measurement can be reduced while performing the high accuracy measurement. it can.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating an electrical configuration of the three-dimensional shape measuring apparatus.

FIG. 3 is a perspective view showing two belt-like light beams and a measurement target for explaining pre-scanning.

FIG. 4 is a diagram showing a two-dimensional light receiving image in a light receiving unit.

FIG. 5A shows a state in which two belt-like light beams collimated to a thickness of the order of μm are projected from two directions by a galvanometer mirror and intersect at an intersection, and FIG. It is a figure showing a light beam which forms the maximum position.

FIG. 6 is a diagram showing a simulation result of a light intensity distribution near an intersection.

FIG. 7 shows a change in the light intensity distribution in the width direction of the light beam observed when the position of the intersection is scanned from the surface of the measurement target in the direction of the optical axis L1 (Z-axis direction) from −90 μm to 90 μm. It is a figure showing the result of simulation.

FIG. 8 shows the same conditions as in FIG.
FIG. 11 is a diagram illustrating a result of simulating a change in a light intensity signal with respect to a defocus amount from a surface of a measurement target observed when a CCD pixel having a width is used.

FIG. 9 is a flowchart illustrating a procedure of a measurement operation.

FIG. 10 is a flowchart illustrating a procedure of a measurement operation.

FIG. 11 is a perspective view showing an external appearance of an embodiment of a three-dimensional shape measuring apparatus according to the present invention.

FIG. 12 is a diagram showing a modification of the camera unit.

FIG. 13 is a view showing another modification of the camera unit.

FIG. 14 is a view showing another modification of the camera unit.

FIG. 15 is a configuration diagram showing a conventional confocal optical system.

FIG. 16 is a diagram showing a light intensity distribution when light from a point light source passes through an optical system having a certain wavefront aberration.

FIG. 17 is a diagram showing a light intensity distribution when light from a point light source passes through an optical system having a certain wavefront aberration and specularly reflected light passes through the optical system again.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Sample stand 20 Illumination means 27a, 27b Galvano mirror 30 Objective optical system 31 Objective lens group 40 Light receiving means 41 Photoelectric conversion element 42 Light receiving means 43 Light receiving means (second measuring means) 53 Sample table driving part 54 Mirror driving part 55 Zoom drive Unit 63 CPU (first measurement control means, second measurement control means,
Coordinate conversion means) 77 signal level detection means 78 position determination means 79 focus determination means 80 range setting means (measurement area determination means) 90 triangulation measurement device (first measurement means)

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Claims (22)

[Claims] An illumination means for illuminating a measurement target with two light beams which are irradiated from different directions and intersect at a predetermined position, and an objective optical system for taking in measurement light from the measurement target illuminated by the illumination means And a light receiving means in which a plurality of photoelectric conversion elements are arranged. Each of the plurality of photoelectric conversion elements receives the measurement light captured by the objective optical system, A three-dimensional shape measuring device for outputting a signal. 2. The three-dimensional shape measuring apparatus according to claim 1, wherein each of the two light beams is a collimated light beam. 3. The three-dimensional shape measuring apparatus according to claim 1, wherein each of the two light beams is a light beam converging in the vicinity of the predetermined position crossing each other. . 4. A three-dimensional shape measuring apparatus according to claim 1, wherein said light receiving means comprises a plurality of photoelectric conversion elements arranged two-dimensionally. apparatus. 5. The three-dimensional shape measuring apparatus according to claim 4, wherein an irradiation angle of the light beam with respect to an optical axis of the objective optical system when the object to be measured is irradiated with at least one of the two light beams. And a position determining unit that determines a position of the surface of the measurement target in the optical axis direction based on a position of the photoelectric conversion element that has received the measurement light in the light receiving unit. 3D shape measuring device. 6. The three-dimensional shape measurement apparatus according to claim 5, further comprising an intersection moving means for moving a position of the intersection where the two light beams intersect in a predetermined direction. apparatus. 7. The three-dimensional shape measuring apparatus according to claim 5, further comprising a sample moving means for moving the object to be measured in a predetermined direction. 8. The three-dimensional shape measuring apparatus according to claim 1, wherein each of the two light beams is a band-like light beam that linearly intersects with each other. 9. The three-dimensional shape measuring apparatus according to claim 1, wherein a position of an intersection of the two light beams and a focal point of the objective optical system coincide with each other. Shape measuring device. 10. The three-dimensional shape measuring apparatus according to claim 9, wherein an aperture angle of said objective optical system is smaller than an irradiation angle of said two light beams with respect to an optical axis of said objective optical system. A three-dimensional shape measuring device, characterized in that: 11. A three-dimensional shape measuring apparatus according to claim 10, wherein said light receiving means includes a row of photoelectric conversion elements arranged at a position conjugate with a focal point of said objective optical system with respect to said objective optical system. A three-dimensional shape measuring device, characterized in that: 12. A three-dimensional shape measuring apparatus according to claim 11, wherein a focal point moving means for moving a focal point of said objective optical system in said optical axis direction, and wherein electric signals output from said plurality of photoelectric conversion elements are maximum. A position judging means for judging the position of the focal point at the time of (1) as the surface position of the object to be measured. 13. The three-dimensional shape measuring apparatus according to claim 11, wherein the sample moving means for moving the object to be measured in the optical axis direction, and wherein the electric signals output from the plurality of photoelectric conversion elements are maximum. A three-dimensional shape measuring apparatus, comprising: position determining means for determining a surface position of the measurement target based on a movement amount of the measurement target. 14. The three-dimensional shape measuring apparatus according to claim 9, wherein each of the two light beams is a band-like light beam and linearly intersects each other in a direction orthogonal to an optical axis of the objective optical system. A three-dimensional shape measuring device, characterized in that: 15. The three-dimensional shape measuring apparatus according to claim 14, wherein the object to be measured is in a direction orthogonal to both an intersection line formed by an intersection of the two band-shaped light beams and an optical axis of the objective optical system. A three-dimensional shape measuring apparatus comprising a sample moving means for moving the object. 16. The three-dimensional shape measuring apparatus according to claim 1, wherein an irradiation angle of the light beam with respect to an optical axis of the objective optical system when the measurement object is irradiated with at least one of the two light beams. And position determination means for determining the position of the surface of the measurement object in the optical axis direction based on the position of the photoelectric conversion element that has received the measurement light of the light receiving means, and the focal point of the objective optical system Relative moving means for relatively moving the objective optical system with respect to the measurement object in the optical axis direction of the objective optical system; and relative movement of the focal point of the objective optical system by the relative moving means based on the determination result by the position determining means. Range setting means for setting a range, wherein the relative movement means moves the focal point of the objective optical system relative to the measurement target only in the set relative movement range. Three-dimensional shape measuring apparatus, characterized in that the shall. 17. A first measuring means for measuring first position data relating to a surface position of a measuring object, a second measuring means for measuring second position data relating to a surface position of the measuring object, and the first measuring means. Measuring area determining means for determining a measuring area based on the obtained first position data; measuring area determined by the measuring area determining means after obtaining the first position data using the first measuring means And a measurement control means for obtaining the second position data using the second measurement means within the three-dimensional shape measurement apparatus. 18. The three-dimensional shape measuring apparatus according to claim 17, wherein the measurement accuracy of the first position data measured by the first measuring means is the measurement accuracy of the second position data measured by the second measuring means. A three-dimensional shape measuring device characterized by lower accuracy. 19. The three-dimensional shape measuring apparatus according to claim 17, wherein each of the first measuring means and the second measuring means sets a focal point of the objective lens and a measurement target relative to an optical axis direction of the objective lens. A three-dimensional shape measuring apparatus for measuring the surface position of an object to be measured by moving the objective lens, wherein the objective lens is shared by the first measuring means and the second measuring means. 20. A three-dimensional shape measuring apparatus according to claim 17, wherein said first measuring means measures a surface position of a measuring object by a triangulation method, and said second measuring means measures a focal point of an objective lens. A surface position of the object to be measured by moving the object relative to the object to be measured in the optical axis direction of the objective lens. 21. The three-dimensional shape measuring apparatus according to claim 17, further comprising a coordinate conversion unit, wherein the first measurement unit and the second measurement unit are each based on a coordinate system different from each other. Wherein the coordinate conversion means converts the first position data measured by the first measurement means into a coordinate system of the second measurement means, and the measurement area determination means comprises: A three-dimensional shape measuring apparatus for determining a measurement area based on first position data converted into a coordinate system of a measuring means. 22. Position data relating to a surface position of a measurement target is measured with a first accuracy, a measurement region is determined based on the measured position data, and the position data is converted to the first position within the determined measurement region. A three-dimensional shape of the object to be measured, the position being measured with a second accuracy higher than the second accuracy, and using the position data measured with the second accuracy.