JP4753657B2 - Surface shape measuring apparatus and surface shape measuring method - Google Patents

Description

  The present invention relates to a surface shape measuring device and a surface shape measuring method for measuring a contour shape of a surface of a measurement object, and particularly to a surface shape measuring device and a surface for measuring the contour shape in a non-contact manner when the surface of the measurement object is a mirror surface. The present invention relates to a shape measuring method.

  Conventionally, as a method of measuring the contour shape of the surface of a measurement object, a stylus method for detecting displacement of the stylus caused by unevenness of the surface while bringing the stylus into contact with the surface of the measurement object (for example, Patent Document 1 below) ) And an optical scanning shape measurement method (for example, Patent Document 2 below) is known in which a light beam is projected onto the surface of the object to be measured and the scattered light is received by a light receiving element to measure the distance to the surface of the object to be measured. Yes.

  Among them, in the optical scanning shape measurement method, as shown in FIG. 1A, spot light is projected from the light projecting portion S toward the measurement object surface MP1, and the resulting scattered light is reflected on the light receiving surface R. The received maximum luminance position P1 is detected. Then, on the measurement surface MP2 where the distance to the light projecting part S is different from the measurement object surface MP1, the position P1 detected when the maximum luminance position P2 at which the scattered light is received by the light receiving surface R is the measurement object surface MP1. Therefore, the distance to the surface of the object to be measured is measured using the difference in position.

JP-A-5-264213 JP 2001-183117 A

However, when the surface shape of an object having a mirror-finished surface such as a mold is to be measured as the measurement object, the surface of the measurement object may be damaged by the stylus method as described above. There was a problem that it could not be used.
In addition, according to the above-described conventional optical scanning shape measurement method, the light beam projected on the surface of the measurement object is regularly reflected on the surface, so that not only the distance between the light projecting portion and the surface of the measurement object Further, since the light receiving position on the light receiving surface changes depending on the incident angle of the light beam, there is a problem in that the distance to the surface of the measurement object cannot be measured. This state is shown in FIG.
Now, it is assumed that the mirror surfaces MP3 and MP1 are equidistant from the light projecting unit S, and the mirror surface MP3 is slightly inclined as compared to the mirror surface MP1. For this reason, the reflected light obtained by regular reflection of each spot light incident on the measurement object surfaces MP3 and MP1 is received at different positions P3 and P1 of the light receiving surface R. In this way, if the conventional optical scanning shape measurement method is used to measure the surface shape of the mirror surface, the light receiving position on the light receiving surface is affected by the unknown inclination of the surface of the object to be measured, so the distance to the surface of the object to be measured is accurate. Cannot be measured.

  In view of the above problems, an object of the present invention is to provide a surface shape measuring device and a surface shape measuring method for measuring the contour shape in a non-contact manner even when the surface of the measurement object is a mirror surface.

  In order to achieve the above object, in the present invention, the spot light from the light projecting unit drives the light receiving surface that receives the reflected light reflected by the surface of the measurement object, which is a mirror surface, in the direction including the normal component, The optical axis position of the reflected light is determined based on the change of the light receiving position accompanying the displacement of the light receiving surface in the normal direction, and the intersection position of the optical axis of the reflected light and the light projecting axis of the spot light is determined on the surface of the measurement object. Determine the position of the measurement point.

  That is, the surface shape measuring apparatus according to the first embodiment of the present invention has a light projecting unit that projects spot light onto the surface of the measurement object that is a mirror surface, and a light receiving surface that receives reflected light of the spot light reflected from the surface of the measurement object. A light receiving portion, and for each measurement point on the surface of the object to be measured, spot light is projected and the reflected light is received by the light receiving portion, and the position of the measurement point is obtained based on the light receiving position on the light receiving surface. A surface shape measuring device for measuring the surface shape of the surface of the object to be measured, the light receiving surface driving unit for driving the light receiving surface in a direction including the normal component thereof, and light reception accompanying displacement of the light receiving surface in the normal direction A reflected optical axis position determining unit that determines the optical axis position of the reflected light based on a change in position, and a position measuring unit that determines an intersection position between the optical axis of the reflected light and the projection axis of the spot light as the position of the measurement point And comprising.

  The spot light projected from the light projecting part is reflected in various directions according to the inclination direction of the surface of the measurement object. The surface shape measuring device always keeps the light projecting part and light receiving surface to follow the inclination of the surface of the measured object so that the reflected light receiving position does not jump out of the light receiving surface while changing the measurement point sequentially. It is desirable to control so that the light receiving position is located at a predetermined position (preferably in the center) of the light receiving surface. The light receiving position on the light receiving surface can be changed by changing the relative position between the light projecting unit and the light receiving unit and the measurement object, or by changing the projection direction of the spot light by the light projecting unit. In this case, it is desirable that there is no variation in the intervals between the measurement points, that is, the projection positions of the spot light.

For this reason, the surface shape measuring apparatus includes a measurement head relative position changing unit that moves a measurement head having a light projecting unit and a light receiving unit relative to the measurement object, and a measurement head direction changing unit that changes the orientation of the measurement head. The projection position on the surface of the measurement object is kept constant by moving the measurement head relative to the measurement object by the measurement head relative position changing unit and changing the direction of the measurement head by the measurement head direction changing unit. It is preferable to further include a light projection axis adjusting unit that adjusts the light receiving position on the light receiving surface.
The light projecting axis adjustment unit is configured such that the light receiving surface is positioned at a predetermined position (for example, an intermediate point of all strokes) by the light receiving surface driving unit and the light receiving position is a predetermined reference position (for example, the center of the light receiving surface). You may adjust so that it may become.

  By adjusting the light projecting axis of the light projecting unit in this way, it is possible to prevent the light receiving position of the reflected light from jumping out of the light receiving surface while the surface shape measuring device sequentially changes the measurement points. In addition, it is possible to prevent the projection positions (measurement points) of the spot light from greatly moving and adjusting the intervals between the measurement points when the projection axis is adjusted.

Further, as will be described later, the light projecting unit and the light receiving unit are provided in the measuring head so that the light projecting axis of the spot light and the predetermined normal line of the light receiving surface are included in the same plane, Consider a case where the posture (direction) of the measuring head is controlled so that the incident angle of the spot light on the surface of the object to be measured is changed while a plane including a predetermined normal line of the light receiving surface is orthogonal to a certain reference surface.
At this time, if the incident azimuth of the spot light incident on the surface of the measurement object with respect to the reference surface matches the inclination direction of the surface of the measurement object with respect to the reference surface, the spot light reflected on the surface of the measurement object is converted into the incident azimuth and the reference Since the light is reflected in the opposite direction on the surface, the light receiving position on the light receiving surface is within the straight line where the light receiving surface and the plane including the predetermined normal of the light receiving surface and the light receiving surface intersect even if the incident angle changes. Move with.

By utilizing such a geometric relationship, the surface shape measuring apparatus may further include an inclination direction determining unit that determines an inclination direction of the surface of the measurement object at a measurement point with respect to a predetermined reference plane.
And the measuring head in which the light projecting part and the light receiving part are provided so that the light projecting axis of the spot light and the predetermined normal of the light receiving surface are included in the same plane, and the direction of the measuring head for changing the direction of the measuring head And the tilt direction determination unit made the plane including the light projection axis of the spot light and the predetermined normal of the light receiving surface orthogonal to the predetermined reference plane by the measuring head direction changing unit. In this state, the incident angle of the spot light on the surface of the object to be measured is changed.At this time, the movement of the light receiving position accompanying the change in the incident angle is such that the plane including the light projecting axis and the predetermined normal of the light receiving surface and the light receiving surface are The incident azimuth of the spot light incident on the surface of the measurement object generated on the intersecting straight line may be searched to determine the incident azimuth as the inclination direction of the surface of the measurement object.
When spot light is incident in the tilt direction of the surface of the measurement object, the normal direction of the surface of the measurement object is equal to the bisector of the angle formed by the projection axis direction of the spot light and the optical axis direction of the reflected light. Become. Here, the direction of the optical axis of the spot light is known, and the direction of the optical axis of the reflected light can also be measured as described above. Therefore, the normal direction of the surface of the measurement object can be determined as the direction of the bisector of the angle formed by the light projection axis direction of the spot light and the optical axis direction of the reflected light. The surface shape measuring apparatus may include a normal direction determining unit that determines the normal direction of the surface of the measurement object in this way.
As the spot light, parallel light is preferably used in order to clearly measure the light receiving position on the light receiving surface.

  Furthermore, in the surface shape measuring method according to the second embodiment of the present invention, spot light is projected at each measurement point on the surface of the measurement object that is a mirror surface, and the reflected light is received by the light receiving surface. In the surface shape measurement method for measuring the surface shape of the surface of the measurement object by determining the position of the measurement point based on the position, the light receiving surface is driven in a direction including the normal component thereof, and the normal direction of the light receiving surface is determined. The optical axis position of the reflected light is determined based on the change of the light receiving position accompanying the displacement, and the intersection position between the optical axis of the reflected light and the light projection axis of the spot light is determined as the position of the measurement point.

  At this time, by moving the measuring head having the light projecting portion and the light receiving portion relative to the measurement object and changing the direction of the measurement head, the light receiving surface is maintained with the projection position on the surface of the measurement object kept constant. The upper light receiving position may be adjusted. Further, the light receiving position may be adjusted to be a predetermined reference position of the light receiving surface in a state where the light receiving surface is positioned at a predetermined position by the light receiving surface driving unit.

Furthermore, the surface of the object to be measured is provided by providing the light projecting portion and the light receiving surface on the measuring head so that the light projecting axis of the spot light and the predetermined normal of the light receiving surface are included in the same plane, and changing the direction of the measuring head. The plane including the light projection axis of the spot light and the predetermined normal line of the light receiving surface is made orthogonal to the predetermined reference plane by changing the incident direction of the spot light on the surface and changing the direction of the measuring head in each incident direction In the state, the incident angle of the spot light on the surface of the object to be measured is changed, and the movement of the light receiving position accompanying the change in the incident angle at this time is a plane including the light projection axis of the spot light and a predetermined normal line of the light receiving surface. The incident direction of the spot light generated on the straight line intersecting the light receiving surface may be determined as the inclination direction of the surface of the measurement object at the projection position of the spot light with respect to a predetermined reference surface.
Further, based on the direction of the optical axis of the reflected light determined in a state where the incident direction of the spot light is oriented in the determined tilt direction, and the direction of the known light projecting axis of the spot light The normal direction of the surface of the measurement object may be determined.

  According to the present invention, it is possible to accurately measure the contour shape of a measurement object having a mirror surface without damaging the surface.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 2 is an overall perspective view of the surface shape measuring apparatus according to the embodiment of the present invention. The surface shape measuring apparatus 1 includes a table 2 for placing a workpiece such as a mold as a measurement object whose surface is mirror-finished, and a measuring head 3 for detecting the surface shape on the table 2 in a non-contact manner. The head direction changing mechanism 4 that can freely change the direction (posture) of the measuring head 3 by freely rotating the measuring head 3 around the three axes orthogonal to each other while supporting the measuring head 3, and the head A head position changing mechanism 5 capable of moving the head direction changing mechanism 4 in any of the XYZ directions while supporting the direction changing mechanism 4 is provided.

FIG. 3 is a cross-sectional view of the measuring head 3 shown in FIG. The measuring head 3 includes a light projecting unit 6 that projects spot light, which is parallel light, on the work surface, and a light receiving unit 7 that has a light receiving surface 71 that receives regular reflection light of the spot light reflected on the work surface. As such a light receiving surface 71, an element such as a two-dimensional CCD or a two-dimensional PSD that receives incident light on a two-dimensional plane and outputs a signal corresponding to the two-dimensional coordinates of the light receiving position is used.
The light projecting unit 6 shields other than the light emitting unit 61, the illumination lens 62 that changes the emitted light from the light emitting unit 61 that is a substantially point light source to parallel light, and the central part of the parallel light that has passed through the illumination lens 62. And an aperture plate 63 for producing spot light.
The light receiving unit 7 includes a light receiving surface 71 that receives specularly reflected light of the spot light, a condensing lens 72 that collects the specularly reflected light of the spot light on the light receiving surface 71, and a straight line that extends in the normal direction of the light receiving surface 71. A moving guide 73 and a light receiving surface driver 74 that drives the light receiving surface 71 along the linear guide 73 are provided.

  In the light projecting unit 6 and the light receiving unit 7, the light projecting axis of the spot light of the light projecting unit 6 and the predetermined normal line of the light receiving surface 71 are the same plane (hereinafter referred to as “optical axis surface LP”). ) To be fixed to the measuring head 3. For example, the light projecting unit 6 and the light receiving unit 6 receive light so that the light projecting axis of the spot light of the light projecting unit 6 and the normal line of the light receiving surface 71 passing through the center C of the light receiving surface 71 are included in the optical axis plane LP. The unit 7 may be provided in the measurement head 3.

  Returning to FIG. 2, the head position changing mechanism 5 can be driven in the Y direction while supporting the movable member 51 that supports the head direction changing mechanism 4 provided with the measurement head 3 and the movable member 51. The Y-direction drive unit 52, the X-direction drive unit 53 capable of driving in the X direction while supporting the Y-direction drive unit 52, and driving in the Z-direction while supporting the X-direction drive unit 53 are supported. And a possible column 54.

  Therefore, the head position changing mechanism 5 can move the measuring head 3 relative to the workpiece, which is a measurement object, and forms a measuring head relative position changing unit according to the claims of the present application. In this embodiment, the measurement head relative position changing unit realizes the relative movement between the measurement head 3 and the workpiece by moving the measurement head 3, but instead of or in addition to this, The relative movement between the measuring head 3 and the workpiece may be realized by moving the workpiece side. For this purpose, a workpiece moving mechanism that can move the workpiece in any of the XYZ directions or any of them may be provided.

4A is a perspective view of the head direction changing mechanism 4 shown in FIG. The head direction changing mechanism 4 includes a first motor 41, a second motor 42, and a third motor 43 that give a rotational motion about three axial directions orthogonal to each other.
Here, the first motor can rotate and drive the measurement head 3 with the first direction perpendicular to the optical axis plane LP of the measurement head 3 as a rotation axis while supporting the measurement head 3. In addition, the second motor can rotate the first motor about the second direction orthogonal to the first direction in the XY plane in the drawing while supporting the first motor. Furthermore, the third motor can rotate the second motor about the Z-axis direction as a rotation axis while supporting the second motor.

  As described above, the head direction changing mechanism 4 includes the motors 41 to 43 that give rotational motion about the three orthogonal axes, thereby measuring the three axes orthogonal to each other while supporting the measuring head 3. It is possible to freely change the incident angle and incident direction of the spot light incident on the work by rotating the head 3. Here, the head direction changing mechanism 4 forms a measuring head direction changing unit according to the claims of the present application. In the present embodiment, the incident angle and the incident direction of the spot light incident on the workpiece are changed by changing the direction of the measuring head 3 itself, but instead of or in addition to this, the workpiece side May be realized by relatively changing the incident angle and the incident azimuth of the spot light incident on the workpiece by moving the workpiece while rotating the three-axis direction. You may provide the workpiece | work direction change mechanism which rotates a workpiece | work using one or all the axes as a rotating shaft, and the workpiece | work movement mechanism which can move to either of XYZ directions or any of them.

  FIG. 5 is a block diagram of the surface shape measuring apparatus 1 of FIG. The surface shape measuring apparatus 1 drives the head direction changing mechanism 4 and the head position changing mechanism 5 described above to control the position and direction of the measuring head 3 and the reflected light output from the light receiving surface 71. And a signal processing circuit 82 for inputting an analog signal indicating the light receiving position and outputting it as a digital position signal. The head controller 81 controls the position of the light receiving surface 71 by controlling the light receiving surface driving unit 74 to move the light receiving surface 71 in the normal direction.

  Further, the surface shape measuring apparatus 1 displaces the light receiving surface 71 by the light receiving surface driving unit 74 and measures the optical axis of the reflected light reflected from the workpiece surface based on the change in the light receiving position on the light receiving surface 71 that occurs at that time. And the intersection position of the optical axis of the reflected light and the projection axis of the known spot light as the relative position from the measurement head 3 at each measurement point. While positioning the measurement head 3 at the measurement position of each measurement point by the position measurement unit 84 to be determined, the head position change mechanism 5 and the head direction change mechanism 4, the relative position information from the position measurement unit 84 is read and a known measurement is performed. A surface shape calculation unit 85 is provided that calculates the position of each measurement point based on the position and direction information of the head 3 and calculates the surface shape of the workpiece.

Furthermore, the surface shape measuring apparatus 1 projects the spot light projected on the workpiece surface by moving the measuring head 3 by the head position mechanism 5 and changing the direction of the measuring head 3 by the head direction changing mechanism 4. A light projection axis adjusting unit 86 is provided for adjusting the light receiving position on the light receiving surface 71 while keeping the position constant.
Furthermore, the surface shape measuring apparatus 1 includes an inclination direction determining unit 87 that determines an inclination direction at a measurement point of a workpiece with respect to a reference surface predetermined on, for example, the table 2 surface (XY surface). Furthermore, the surface shape measuring apparatus 1 includes a normal direction determining unit 88 that determines the normal direction on the measurement surface of the workpiece with respect to the reference surface as described above.

  With reference to FIG. 6, a surface shape measuring method according to an embodiment of the present invention will be described. The above-described surface shape calculation unit 85 positions the measurement head 3 at the measurement position of the measurement point on the workpiece by the head position change mechanism 5 and the head direction change mechanism 4. The light projecting unit 6 projects spot light onto the workpiece surface (measurement surface MP), and the light receiving unit 7 receives the reflected light regularly reflected by the measurement surface MP at the light receiving position A of the light receiving surface 71 (FIG. 6). (A)). The reflected optical axis position determining unit 83 stores the position A at this time.

Next, the reflected optical axis position determining unit 83 displaces the light receiving surface 71 in the normal direction by the light receiving surface driving unit 74 and positions the light receiving surface 71 at the position 71 ′. In this state, the light receiving unit 7 receives the reflected light regularly reflected by the measurement surface MP at the light receiving position B of the light receiving surface 71 ((B) of FIG. 6). The reflected optical axis position determining unit 83 stores the position B at this time.
Then, the reflected light regularly reflected on the measurement surface MP by the known position 71 (FIG. 6A) and the known position 71 ′ (FIG. 6A) of the light receiving surface 71 and the stored positions A and B. Since the coordinates of the two points through which the optical axis passes are clarified, the reflected optical axis position determining unit 83 determines the relative optical axis of the reflected light regularly reflected by the measurement surface MP from the measurement head 3 based on the position information. Determine the position.

Since the measurement point P on the measurement surface MP can be calculated as the intersection of the optical axis of the reflected light and the optical axis of the projection light, and the relative position of the optical axis of the projection light from the measurement head 3 is known, the position measurement unit 84 is a measurement point on the measurement surface MP as an intersection of these two optical axes based on the relative position of the optical axis of the reflected light from the measurement head 3 and the relative position of the optical axis of the projection light from the measurement head 3. The relative position of P from the measuring head 3 is calculated.
Then, the surface shape calculation unit 85 reads the relative position information from the position measurement unit 84 at each measurement point on the workpiece, and calculates the position of each measurement point based on the known position and direction information of the measurement head 3. The surface shape of the workpiece is calculated.

  FIG. 7 is an explanatory diagram of a method of adjusting the optical axis of the spot light by the light projection axis adjusting unit 86 shown in FIG. As described above, the surface shape measuring apparatus 1 always tilts the measurement head 3 so that the light receiving position of the reflected light does not jump out of the light receiving surface 71 while the measurement points P are sequentially changed. It is desirable that the light receiving position on the light receiving surface 71 is controlled to be located at a predetermined position (preferably at the center of the light receiving surface 71). Further, at this time, it is necessary to prevent the projection position (measurement point) of the spot light from moving greatly by moving and rotating the measurement head 3 and to prevent variation in the interval between the measurement points.

  Therefore, each time the calculation of the position P is completed at each measurement point, the light projecting axis adjustment unit 86 moves the measurement head 3 relative to the workpiece by the head position change mechanism 5 and measures by the measurement head direction change unit. By changing the direction of the head, when the light receiving surface 71 is at a predetermined neutral position, the position and posture of the measuring head 3 are finely adjusted so that the light receiving position is located at the center C of the light receiving surface 71.

  The light projection axis adjustment unit 86 performs such adjustment of the posture of the measurement head 3 before moving the measurement head 3 to the next measurement point after calculating the position at each measurement point. The spot light can make the current projection position P known. Further, since the position of the measuring head 3 and the optical axis position of the spot light of the light projecting unit 6 are also known, the light projecting axis adjusting unit 86 maintains the state in which the spot light of the light projecting unit 6 projects to this position P. The measuring head 3 can be moved relative to the workpiece by the head position changing mechanism 5 and the direction of the measuring head can be changed by the measuring head direction changing unit.

  For example, in the example of FIG. 7B, the projection position P of the spot light of the light projecting unit 6 is set by moving the measuring head 3 in the direction indicated by the arrow 91 in the figure and rotating it in the direction indicated by the arrow 92 in the figure. While keeping constant, the position and posture of the measuring head 3 are finely adjusted so that the light receiving position is located at the center C of the light receiving surface 71. Alternatively, the position of the measurement head 3 is finely adjusted while keeping the projection position P constant by simply moving the measurement head 3 in the direction of an arrow 97 that is parallel to the light projection axis of the spot light.

The light projection axis adjustment unit 86 calculates the inclination direction of the measurement surface MP at the projection position P based on the known projection position P of the spot light, the optical axis position of the spot light, and the position information of the light reception position A, The amount of movement and the amount of rotation for adjusting the position and orientation of the measuring head 3 may be calculated so that the light receiving position is located at the center C of the light receiving surface 71.
Alternatively, the light projection axis adjusting unit 86 obtains the change direction of the light receiving position in each case while finely moving the position and orientation of the measuring head 3 in each direction, and the light receiving position is in the direction of the center C of the light receiving surface 71. The moving direction and the changing direction of the posture may be acquired, and the light receiving position may be adjusted in the changing direction until it reaches the center C of the light receiving surface 71.

  With reference to FIGS. 8-10, the method to determine the inclination direction of the measurement surface using the surface shape measuring apparatus 1 of FIG. 2 is demonstrated. Hereinafter, a case where the inclination direction of the measurement surface MP with respect to a predetermined reference surface RP as shown in FIG. The reference plane RP may be freely set with respect to the XYZ coordinate system of the stage 2 of the surface shape measuring apparatus 1 shown in FIG. 2, and may simply be considered as the XY plane of the stage 2. For the sake of simplicity, the two orthogonal directions in the reference plane RP are defined as the X2 axis and the Y2 axis, and the direction orthogonal to the reference plane RP is defined as the Z2 axis.

First, the posture of the measurement head 3 is controlled so that the optical axis plane LP of the measurement head 3 described above is orthogonal to the reference plane RP. The measurement head 3 is rotated as indicated by an arrow 93 in the figure while maintaining the relationship in which the optical axis plane LP is orthogonal to the reference plane RP, that is, using the direction AL orthogonal to the optical axis plane LP as a rotation axis. . Here, the incident angle θ _i of the spot light with respect to the measurement surface MP is defined as the angle formed by the incident direction of the spot light and the normal direction n of the measurement surface MP at the measurement point P as shown in FIG. Then, the incident angle θ _i of the spot light with respect to the measurement surface MP changes as the measurement head 3 rotates.

As the incident angle θ _i of the spot light changes, the light receiving position at which the reflected light is received by the light receiving surface 71 also changes. In FIG. 8B, the locus drawn by the light receiving position when the incident angle θ _i of the spot light is changed in the state of FIG. In the state shown in (A) in FIG. 8, incident orientation theta _a spot light to the reference plane RP is different from the inclination direction of the measurement surface relative to the reference plane RP.
Here, incident orientation theta _a spot light to the reference plane RP is incident spot light relative to the (X2 direction in the illustrated example) a predetermined reference direction of the reference plane RP as shown in (B) of FIG. 9 Azimuth angle θ _a (that is, an angle formed by an intersection point between the optical axis plane LP and the reference plane RP and a predetermined reference direction of the reference plane RP).

  At this time, since the spot light reflected by the measurement surface MP is not reflected in the opposite direction with respect to the reference surface RP with respect to the incident direction, the reflected light deviates from the optical axis plane LP. Accordingly, the light receiving position at which the reflected light is received by the light receiving surface 71 moves at a position deviated from the center line, which is a straight line where the light receiving surface 71 and the optical axis plane LP intersect, as shown in FIG.

Next, as shown in (A) of FIG. 10, the incident orientation theta _a spot light to the reference plane RP, to match the inclination direction of the measurement surface relative to the reference plane RP, the measuring head 3 in the same manner as FIG. 8 Consider the case of rotating. Then, since the spot light reflected on the measurement surface MP is reflected only in the opposite azimuth on the reference plane RP with respect to the incident azimuth, the reflected light does not deviate from the optical axis plane LP. Accordingly, the light receiving position at which the reflected light is received by the light receiving surface 71 moves on the center line which is a straight line where the light receiving surface 71 and the optical axis plane LP intersect as shown in FIG.

Therefore, the tilt direction determination unit 87 sequentially changes the incident direction of the spot light on the measurement surface MP by controlling the head position change mechanism 6 and the head direction change mechanism 4 to change the position and orientation of the measurement head 3. .
At this time, in each incident azimuth, the position and orientation of the measuring head 3 are changed to keep the optical axis plane LP orthogonal to the reference plane RP, and the direction orthogonal to the optical axis plane LP is measured as the rotation axis. The head 3 is rotated to change the incident angle of the spot light on the measurement surface MP.

  The locus of the light receiving position accompanying the change in the incident angle is detected on the light receiving surface 71 from the output signal, and the locus of the light receiving position is on the intersection line between the optical axis plane LP and the light receiving surface 71 (that is, on the center line of the light receiving surface 71). The incident direction of the spot light is determined as the inclination direction of the measurement surface MP at the measurement point P with respect to the reference surface RP.

When the spot light is incident in the tilt direction of the surface of the measurement object, the normal direction of the surface of the measurement object is the direction of the bisector of the angle formed by the light projection axis direction of the spot light and the optical axis direction of the reflected light Is equal to Here, the direction of the optical axis of the spot light is known, and the direction of the optical axis of the reflected light can also be measured by the reflected optical axis position determining unit 83 as described above.
The normal direction determining unit 88 includes the optical axis direction of the reflected light measured by the reflected optical axis position determining unit 83 in a state where the incident direction of the spot light is oriented in the tilt direction by the tilt direction determining unit 87, and Based on the known projection axis direction of the spot light, the direction of the bisector of the angle formed by the two optical axes is calculated to determine the normal direction of the surface of the measurement object.

  INDUSTRIAL APPLICABILITY The present invention can be used for a surface shape measuring apparatus and a surface shape measuring method for measuring a contour shape of a measurement object surface, and particularly when the measurement object surface is a mirror surface, the surface shape for measuring the contour shape in a non-contact manner. The present invention relates to a measuring apparatus and a surface shape measuring method.

It is a figure explaining the conventional optical scanning type shape measuring method. 1 is an overall perspective view of a surface shape measuring apparatus according to an embodiment of the present invention. It is sectional drawing of the measuring head shown in FIG. (A) is a perspective view of the head direction changing mechanism shown in FIG. 2, and (B) and (C) are operation explanatory views of the head direction changing mechanism. It is a block diagram of the surface shape measuring apparatus of FIG. It is explanatory drawing of the surface shape measuring method by the Example of this invention. It is explanatory drawing of the adjustment method of a light projection part optical axis. It is explanatory drawing (the 1) of the inclination direction determination method. It is a figure explaining the incident angle and incident azimuth | direction of a spot beam. It is explanatory drawing (the 2) of the inclination direction determination method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface shape measuring apparatus 2 Table 3 Measuring head 4 Head direction change mechanism 5 Head position change mechanism

Claims (5)

A light projecting unit for projecting spot light onto the surface of the measurement object, which is a mirror surface, and a light receiving unit having a light receiving surface for receiving reflected light of the spot light reflected on the surface of the measurement object, on the surface of the measurement object For each measurement point, the surface shape of the surface of the object to be measured is obtained by projecting the spot light and receiving the reflected light by the light receiving unit, and determining the position of the measurement point based on the light receiving position on the light receiving surface. In a surface shape measuring device for measuring
A light receiving surface driving unit that drives the light receiving surface in a direction including the normal component;
A reflected optical axis position determining unit that determines an optical axis position of the reflected light based on a change in the light receiving position accompanying a displacement in a normal direction of the light receiving surface;
A position measurement unit that determines an intersection position of the optical axis of the reflected light and the light projection axis of the spot light as the position of the measurement point;
An inclination direction determination unit that determines an inclination direction of the surface of the measurement object at the measurement point with respect to a predetermined reference plane;
A measuring head provided with the light projecting unit and the light receiving unit so that the light projecting axis of the spot light and the predetermined normal of the light receiving surface are included in the same plane;
A measuring head direction changing unit for changing the direction of the measuring head;
In the state where the plane including the light projection axis of the spot light and the predetermined normal line of the light receiving surface is orthogonal to the predetermined reference plane by the measuring head direction changing unit, The incident angle of the spot light on the surface of the object to be measured is changed. At this time, the movement of the light receiving position accompanying the change in the incident angle is caused by the plane including the light projecting axis and the predetermined normal line of the light receiving surface, and the light receiving. Searching for the incident azimuth of the spot light to the surface of the measurement object, which occurs on a straight line intersecting the surface, and determining the incident azimuth as an inclination direction of the surface of the measurement object;
The surface shape measuring apparatus characterized by the above-mentioned. The surface shape measuring apparatus according to claim 1 , further comprising a normal direction determining unit that determines a normal direction of the surface of the measurement object at the measurement point with respect to a predetermined reference plane. The normal direction determining unit is configured to determine the direction of the optical axis of the reflected light determined by the reflected optical axis position determining unit in a state where the incident azimuth of the spot light is oriented in the determined tilt direction, and the spot The surface shape measuring apparatus according to claim 2 , wherein a normal direction of the surface of the object to be measured is determined based on a direction of a known light projecting axis. For each measurement point on the surface of the measurement object that is a mirror surface, spot light is projected and the reflected light is received by the light receiving surface, and the position of the measurement point is obtained based on the light receiving position on the light receiving surface, In the surface shape measuring method for measuring the surface shape of the surface of the measurement object,
The measuring head is provided with the spot light projecting portion and the spot light receiving portion so that the spot light projecting axis and the predetermined normal of the light receiving surface are included in the same plane,
Driving the light receiving surface in a direction including its normal component;
Determining the optical axis position of the reflected light based on the change in the light receiving position accompanying the displacement in the normal direction of the light receiving surface;
Determining the intersection position of the optical axis of the reflected light and the light projection axis of the spot light as the position of the measurement point ;
By changing the direction of the measurement head, the incident direction of the spot light on the surface of the measurement object is changed,
In each incident azimuth, by changing the direction of the measurement head, the measurement object is in a state where the plane including the light projection axis of the spot light and the predetermined normal line of the light receiving surface is orthogonal to a predetermined reference plane. Changing the incident angle of the spot light on the surface,
The spot light in which the movement of the light receiving position accompanying the change in the incident angle occurs on a straight line intersecting the light receiving surface with the plane including the light projection axis of the spot light and a predetermined normal line of the light receiving surface. Is determined as an inclination direction of the surface of the object to be measured at the projection position of the spot light with respect to the predetermined reference plane . The measurement based on the direction of the optical axis of the reflected light determined in a state in which the incident azimuth of the spot light is oriented in the determined inclination direction, and the direction of the known light projection axis of the spot light The surface shape measuring method according to claim 4 , wherein the normal direction of the object surface is determined.

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