JPH11132736A - Confocal optical device and positioning method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a confocal optical device which is provided with a plurality of light sources and a detector array and can position a light receive pin hole array and the detector array with high precision repeatedly, and a positioning method therefor. SOLUTION: This is a method for aligning a detector array 11 with a plurality of light sources 4 of the confocal point optical device which is provided with a plurality of light sources 4 and the detector array 11 having a plurality of detection elements and measures the intensity of light reflected on a workpiece 14 to measure a shape of a surface thereof. A light collection position of the light projected from the plurality of light sources 4 is moved in the direction of Z-axis for predetermined object 14, a peak value of a signal level of at least two detection elements is detected, and an average value of the peak values is computed to a control a position of the detector array 11 to a high average value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a confocal optical device for measuring a surface shape of an object, and a method for aligning a detector array and a light receiving pinhole array thereof.

[0002]

2. Description of the Related Art Conventionally, a confocal optical device having a plurality of light sources and a detector array having a plurality of detection elements arranged corresponding to the light sources has been widely used as an apparatus for measuring the surface shape of an object. Have been. FIG. 11 shows, for example, Japanese Patent Application No.
This is an example of a confocal optical device disclosed in Japanese Patent No. 194054 (not disclosed), and a conventional technique will be described below with reference to the same drawing. In FIG. 1, one of the plurality of optical paths is shown as a representative.

In FIG. 1, light emitted from a light source 1 is shaped into parallel light by a lens 2 and applied to a light projecting pinhole array 3 in which openings are two-dimensionally arranged. The light transmitted through the light projecting pinhole array 3 becomes a plurality of light sources 4, passes through a beam splitter 5, is condensed by lens groups 6 </ b> A and 6 </ b> B, and is projected on a work 8 as projected light.
The light reflected on the work 8 passes through the lens groups 6B and 6A in the direction opposite to the outward path, is reflected by the beam splitter 5 leftward in the drawing, and is placed at a position optically conjugate with the plurality of light sources 4. Then, the light enters the light receiving pinhole array 9 in which the openings are two-dimensionally arranged. Only the light that has passed through the light receiving pinhole array 9 is incident on the detection element of the detector array 11, and the light intensity is detected.

[0004] Here, when the condensed and projected light is focused on the surface of the work 8 (hereinafter referred to as focusing), most of the returned light is a light receiving pinhole array. 9, the signal level of the detection element of the detector array 11 shows a maximum value, while the light condensing position is shifted from the surface of the work 8 in the Z-axis direction (vertical direction in the figure). In this case (hereinafter referred to as out-of-focus), most of the returned light is kicked by the non-opening portion of the light receiving pinhole array 9 and is not input to the detection element, so that the signal level becomes low. At this time, by moving the work 8 or the lens group 6B in the Z-axis direction, the positional relationship between the condensing position and the work 8 is changed, and the position in the Z-axis direction at which the signal level of the detection element becomes maximum is detected. Then, the surface shape of the work 8 can be measured.

At this time, if the position of the light incident on the light-receiving pinhole array 9 and the position of the opening of the light-receiving pinhole array 9 are not precisely aligned, the light will be transmitted to the light-receiving pinhole array 9 when focused. A defect that the light does not enter the opening occurs, and the signal level of the detection element does not reach the maximum value. Therefore, the shape cannot be measured accurately, and the measurement accuracy deteriorates. The same applies to the relationship between the position of the light emitted from the light receiving pinhole array 9 and the position of each detection element of the detector array 11. Therefore, a technique for precisely matching the two is required.

Another example of this confocal optical device is disclosed in Japanese Patent Application Laid-Open No. 4-265918, as shown in FIG. In this publication, instead of the combination of the light receiving pinhole array 9 and the detector array 11,
A confocal optical device using a detector array 11 in which the distance between each detection element is widened is disclosed. Also in this apparatus, unless the position of the light incident on the detector array 11 and the position of the detection element are precisely aligned, the measurement accuracy is deteriorated, and the shape cannot be measured accurately.

[0007]

Conventionally, the position of the light incident on the light receiving pinhole array 9, the position of the opening of the light receiving pinhole array 9, or the position of the light incident on the detector array 11 and the position of the detecting element are determined. As a technique for precisely adjusting the position, for example, there is a technique disclosed in Japanese Patent Application Laid-Open No. 6-9958. The position of the light-receiving pinhole and the detector are aligned so that the amount of light passing through the light-receiving pinhole is maximized. However, what is disclosed in this publication is a technique in which a single light source and a single detection element are used, and a technique for aligning the position of a single light-receiving pinhole. It is very difficult to apply the technique to the alignment technique of the detector array 11 having a plurality of detection elements.

[0008] This is because, as an example of the detector array 11, C is disclosed in Japanese Patent Application Laid-Open No. Hei 4-265918.
Like a CD camera, the arrangement of the detection elements is hundreds of hundreds or more, and it is extremely complicated to adjust the position so that the signal levels of all the detection elements are maximized. This is because there is a problem that the work time is extremely long.

As another adjustment method, as shown in FIG.
4 is installed, a signal output from the detector array 11 is displayed on a monitor 13, and the monitor 13 is observed, and the detector array 11 is controlled so that the amount of light is uniform and maximum for each detection element. There is a technique of performing position alignment. However, in this method, it is difficult to dispose the plane mirror 14 exactly perpendicularly to the optical axis 15 of the confocal optical device, and a part of the surface of the plane mirror 14 shifts the light of the projected light from the condensing position. It is easy to cause a shift in the Z-axis direction, which is the axial direction. As a result, even if the detector array 11 and the light receiving pinhole array 9 are accurately positioned, the distribution of the light displayed on the monitor 13 varies, and there is a problem that the positioning is determined to be incorrect.

[0010] Even if the plane mirror 14 is correctly arranged, the judgment as to whether the amount of light displayed on the monitor 13 is uniform or not depends on the operator who performs the adjustment work. However, it cannot be adjusted with high accuracy. Therefore, it was difficult for beginners and automation was also difficult.

The technique disclosed by the present applicant in the above-mentioned Japanese Patent Application No. 9-194054 is that a concave mirror is provided in place of the work 8 in the confocal optical device shown in FIG. The output signal is observed, and the light-emitting pinhole array 3, the light-receiving pinhole array 9, and the detector array 11 are aligned so that the output signal becomes a beautiful concentric circle. However, in this method, the standard for judging how uniform the concentric circle is varies depending on the operator, and when the concave mirror is inclined with respect to the optical axis 15, even if the alignment is accurate, the concentric circle is inclined. And the adjustment work takes a long time.

As described above, a technique has been disclosed which can easily and precisely repeat the light projected from the plurality of light sources 4 with the light receiving pinhole array 9 and the detector array 11 with high accuracy. Not.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is intended to simply and easily combine light emitted from a plurality of light sources with a light receiving pinhole array and a detector array including a plurality of detecting elements. It is an object of the present invention to provide a confocal optical device capable of accurately and repeatedly positioning with high accuracy, and a positioning method thereof.

[0014]

Means for Solving the Problems, Functions and Effects In order to achieve the above object, the invention according to claim 1 comprises a plurality of light sources 4 projected on predetermined objects 8 and 14; Focusing position moving means 23 for moving the focusing position of the projected light emitted from the plurality of light sources 4 to the predetermined objects 8 and 14 in the optical axis direction of the projected light; Predetermined object 8,1
And a detector array 11 having a plurality of detection elements for detecting the intensity of the light reflected by the light source 4. The detector array 11 is arranged on a plane optically conjugate with the plurality of light sources 4. Detector array moving means 2 for moving at least one of parallel and rotating
1 and a peak for detecting a peak value of each signal level of a signal level output from at least two of the detection elements on the detector array 11 when the condensing position of the projected light is moved. It comprises a value detecting means 26 and a detector array position control means 22 for controlling the position of the detector array 11 by outputting a movement command to the detector array moving means 21 based on the peak value.

According to the present invention, the height of the light-condensing position with respect to a predetermined object such as a work or a plane mirror is moved by the light-condensing position moving means, and the signal output from each detecting element in accordance with the movement. The peak value of the level is obtained by the peak value detecting means, and the position of the detector array is adjusted based on the peak value. For example, alignment is performed so that the peak values of the detection elements at the four corners of the detector array are maximized, or alignment is performed such that the sum of the peak values of all the detection elements on the detector array is maximized. doing.

At this time, the peak value is the maximum light amount of light incident on each detection element when the light condensing position is moved with respect to a predetermined object, that is, the light condensing position is a predetermined object surface. Is the signal level of each detection element at the time of focusing, which corresponds to In the prior art, it is difficult to accurately place the plane mirror at the condensing position, and it is difficult to perform positioning with good reproducibility because the signal level output from the detection element varies depending on the installation conditions. According to the present invention, even if a predetermined object is tilted, the position of the predetermined object is set based on only the light at the time of focusing by moving the predetermined object with respect to the focusing position. Regardless, the positioning can be performed precisely and with high repeatability.

In the prior art, since it is difficult to accurately place the plane mirror at the light condensing position, the reflected light incident on the detector array may be out of focus and its diameter may be increased. However, the accuracy is not sufficient because the alignment is performed on the basis of this, whereas in the present invention, the diameter of the reflected light is the smallest on the detector surface at the time of focusing, and the position based on this position is used as a reference. Since the alignment is performed, the accuracy of the alignment is improved.

In the prior art, a flat mirror having a uniform reflectivity has to be used in order to avoid a difference in the intensity of incident light depending on each detecting element.
In the present invention, since the alignment is performed based on the peak value of the signal level output from each detection element, the influence of the reflectance can be canceled by, for example, taking the sum of the peak values, and it is necessary to use a plane mirror. And alignment can be performed using a predetermined object.

Further, according to the present invention, a plurality of light sources 4 projecting light to predetermined objects 8 and 14 and a plurality of light sources 4 projecting light to the predetermined objects 8 and 14 are provided. A condensing position moving means 23 for moving a condensing position of the projected light in the optical axis direction of the light, a light receiving pinhole array 9 having a plurality of openings, A confocal optical device comprising: a detector array 11 having a plurality of detection elements for detecting the intensity of light that has passed through the opening of the light-receiving pinhole array 9 among the reflected lights reflected by the light-receiving elements 8 and 14. The light receiving pinhole array 9 is connected to the plurality of light sources 4.
Move at least parallel to a plane optically conjugate to
Or a light-receiving pinhole array moving means 28 for performing either one of rotation and rotation, and at least two of the detection elements on the detector array 11 output when the light condensing position of the projected light is moved. A peak value detecting means 26 for detecting a peak value of each signal level of each detecting element, and a movement command to the light receiving pinhole array moving means 28 based on the peak value to output the position of the light receiving pinhole array 9. And a light receiving pinhole array position control means 29 for controlling the position of the light receiving pinhole array.

According to the present invention, similarly to the first aspect, the position of the light receiving pinhole array is adjusted based on the peak value of the signal level output from the detecting element.
For the same reason, the positioning of the light receiving pinhole array can be performed precisely and with high repeatability.

According to a third aspect of the present invention, in the confocal optical device according to the first aspect, an average value of the peak values obtained for at least two detection elements on the detector array 11 is calculated. An average value calculating means 27 for calculating is attached,
The detector array position control means 22 outputs a movement command to the detector array moving means 21 to control the position of the detector array 11 to the larger average value.

According to the present invention, in addition to the functions and effects of the first aspect of the present invention, an average value of peak values at at least two points on the detector array is obtained, and a command from the detector array position control means is issued. Then, the detector array is moved to the higher one of the average values to perform positioning.

That is, as described above, the higher the peak value of the signal level of each detecting element, the better the alignment of the corresponding detecting element. Here, since it takes a long time to adjust the detector array based on the mere peak values of the individual detection elements, the average value of the peak values at a plurality of locations on the detector array is used as an index for positioning. Accordingly, the height of the peak value of the signal level of each of the detection elements can be appropriately evaluated, and the alignment can be performed easily and accurately.

Further, since the numerical value data of the average value is used as an index for the alignment, if the alignment is performed by moving the detector array in a higher direction, the alignment can be performed based on only a simple arithmetic processing. become able to. Therefore, by executing this arithmetic processing by a computer device or the like, the positioning can be adjusted with high accuracy regardless of the skill level of the operator and individual differences, and automation is easy.

According to a fourth aspect of the present invention, in the confocal optical device according to the second aspect, an average value of the peak values obtained for at least two detection elements on the detector array 11 is calculated. The light receiving pinhole array position control means 29 outputs a movement command to the light receiving pinhole array moving means 28 so that the position of the light receiving pinhole array 9 is shifted to the larger one of the average values. Is controlling.

According to the present invention, similarly to the third aspect of the present invention, the light receiving pinhole array is moved to the higher average value to perform the alignment. The alignment of the array can be performed precisely and with high repeatability.

The invention described in claim 5 is the same as the invention described in claim 3.
In the confocal optical device described in the above, frequency calculation means for counting the number of detection elements such that the peak value obtained for the at least two detection elements falls within a predetermined range centered on the average value as a frequency. The detector array position control means 22 outputs a movement command to the detector array moving means 21 so that the average value increase amount when the position of the detector array 11 is moved is a predetermined value. The position of the detector array 11 is controlled so that the average value becomes larger, and the detector array 11 becomes larger.
Is controlling the position.

That is, the effect of using the average value of the peak values as an index at the time of positioning is clear as described above. Even if the detector array is moved, there is almost no difference in the average value, and it is difficult to perform positioning with higher accuracy.

However, even if the average value is the same, the average value is dragged when strong light is incident on some of the detection elements because the intensity distribution of the light source is not uniform or the work is inclined. May rise. In order to judge a state in which many detection elements are uniformly and preferably aligned as a good alignment state, the detector array is aligned so that the signal level of each detection element is uniform. .

Therefore, according to the present invention, the detector array is moved to the higher average value, and the average value does not change much even when the detector array is moved. Is counted as the number of detection elements that fall within a predetermined range centered on this average value, and the detector array is moved to the higher frequency by a command from the detector array position control means. ing.

Thus, if the average values of the peak values are almost the same, it can be determined that the number of the detection elements that are as close as possible to the average value is more appropriately aligned, and the accuracy of the alignment is reduced. Can be improved. That is, by using the frequency as an index in addition to the average value,
Alignment of the detector array can be performed more precisely.

The invention described in claim 6 is the same as the invention in claim 4.
In the confocal optical device described in the above, frequency calculation means for counting the number of detection elements such that the peak value obtained for the at least two detection elements falls within a predetermined range centered on the average value as a frequency. The light-receiving pinhole array position control means 29 outputs a movement command to the light-receiving pinhole array moving means 28 so that the amount of change in the average value when the position of the light-receiving pinhole array 9 is moved is determined. Until the average value does not exceed a predetermined value, the position of the light receiving pinhole array 9 is controlled to the larger average value, and the position of the light receiving pinhole array 9 is controlled to the larger frequency.

According to the present invention, in the same manner as in the fifth aspect of the present invention, the light receiving pinhole array is moved to the higher one of the average values, and the average value does not change so much even if it is moved. The light receiving pinhole array is moved to the higher frequency. The effect of using the average value of the peak values and the frequency as indices is clear as described above, and the positioning of the light-receiving pinhole array can be performed more precisely and more precisely.

According to a seventh aspect of the present invention, a plurality of detection elements project light from a plurality of light sources 4 onto predetermined objects 8 and 14 and are provided at positions optically conjugate with the plurality of light sources 4. And a light receiving pinhole array 9 in which a plurality of openings are arranged.
A confocal optical device for detecting the intensity of the reflected light reflected by the detector array 11 by the detector array 11 or the detector array 11 that receives the light passing through the opening of the light receiving pinhole array 9; Or light receiving pinhole array 9
In the positioning method of (1), the condensing position of the projected light is moved in the optical axis direction of the light with respect to predetermined objects 8 and 14, and the position on the detector array 11 is moved with the movement. A peak value of a signal level output from at least two of the detection elements is detected for each detection element, and the position of the detector array 11 or the light receiving pinhole array 9 is adjusted based on the peak value. .

According to the present invention, the light-condensing position on a predetermined object is moved, and the peak value of the signal level output from the plurality of detecting elements is determined in accordance with the movement, and the detector array or the detector array is determined based on this value. The position of the light receiving pinhole array is adjusted.

That is, the peak value is the maximum light amount of light incident on each detection element when the light condensing position is moved with respect to a predetermined object, and the light condensing position is on the surface of the predetermined object. This is the signal level of the detection element at the time of the focusing that matches. In the prior art, it is difficult to accurately place the plane mirror at the condensing position, and the signal level output from the detection element varies depending on the installation conditions, so that it is difficult to perform positioning with good reproducibility. However, according to the present invention, no matter how the predetermined object is arranged, the predetermined object is moved with respect to the focusing position and the alignment is performed based on only the light at the time of focusing, so that the accuracy is always constant. Good alignment can be performed.

According to the present invention, a plurality of light sources 4 project light onto a predetermined object (8, 14), and a plurality of light sources 4 are positioned at optically conjugate positions with the plurality of light sources 4. Arrange a detector array (11) having a detection element or a light receiving pinhole array (9) in which a plurality of openings are arranged, and the predetermined object (8, 14)
A confocal optical device that detects the intensity of the reflected light reflected by the detector array (11) or the detector array (11) that receives light passing through the opening of the light-receiving pinhole array (9). The detector array (11) or a light receiving pinhole array
In the alignment method of (9), the condensing position of the projected light is moved in the optical axis direction of the light with respect to a predetermined object (8, 14), and the light is detected along with the movement. Detecting the peak value of each signal level of the signal level output from at least two of the detector elements on the detector array (11), calculating the average value of the peak values, and detecting the detector array (11) or The light receiving pinhole array (9) is moved in the direction in which the average value is higher to perform positioning.

That is, as described above, the higher the peak value of the signal level of each detection element, the better the alignment of the corresponding detection element. Here, since it takes a long time to adjust the detector array based on the mere peak values of the individual detection elements, the average value of the peak values of at least two detection elements on the detector array is aligned. By using this index, the height of the peak value of the signal level of each of the detection elements can be appropriately evaluated, and the alignment can be performed easily and accurately.

Further, since the numerical value called the average value is used as an index for positioning, if the detector array is moved in a higher direction, the positioning can be adjusted with high accuracy regardless of the skill level of the workers or individual differences. It is possible and automation is easy.

According to a ninth aspect of the present invention, a plurality of detection elements project light from a plurality of light sources 4 to predetermined objects 8 and 14 and are provided at positions optically conjugate with the plurality of light sources 4. And a light receiving pinhole array 9 in which a plurality of openings are arranged.
A confocal optical device for detecting the intensity of the reflected light reflected by the detector array 11 by the detector array 11 or the detector array 11 that receives the light passing through the opening of the light receiving pinhole array 9; Or light receiving pinhole array 9
In the positioning method of (1), the condensing position of the projected light is moved in the optical axis direction of the light with respect to predetermined objects 8 and 14, and the position on the detector array 11 is moved with the movement. Detecting a peak value of each signal level of a signal level output from at least two of the detection elements, calculating an average value of the peak values, and setting the peak value within a predetermined range around the average value. The number of detection elements that enter is counted as a frequency, and the detector array is shifted to a larger average value until the amount of change in the average value when the position of the detector array 11 is moved does not exceed a predetermined value. 11 or the position of the light-receiving pinhole array 9 is controlled, and the detector array 11 or the light-receiving pinhole array 9
The position of is adjusted.

According to the present invention, the detector array or the pinhole array is moved to the one where the average value of the peak values of at least two detection elements on the detector array is larger, and if the average values are almost the same. When it is determined that the alignment is as good as possible when as many detection elements as possible are in a suitable alignment state, as compared with the case where the signal level of a small number of detection elements is extremely high and the average value is increased. I have. As the means, a frequency, which is the number of the detection elements having the peak value within a predetermined range from the average value, is calculated, and it is determined that the larger the frequency is, the smaller the variation of the signal level output from each detection element is. And moving the detector array or the light receiving pinhole array in that direction.

Accordingly, if the average value of the peak values is substantially the same, it can be determined that the number of the detection elements which are as close as possible to the average value is as many as possible. Can be improved. That is, by using the frequency as an index in addition to the average value, the alignment of the detector array can be performed more precisely.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

The first embodiment will be described with reference to FIGS. FIG. 1 shows a configuration of the confocal optical device according to the present embodiment when positioning the detector array. In the figure, the confocal optical system is the same as the configuration shown in FIG. 12, and the description of the same reference numerals in the figure is omitted.

The detector array 11 can be moved in the Z, Y, and θ directions in the figure by, for example, a detector array moving means 21 that combines a pulse motor, a linear motion stage, and a rotary stage. And the angle in the θ direction are controlled by the output from the detector array position control means 22. For example, a plane mirror 14 for positioning is disposed on the focusing position moving means 23 which includes a pulse motor and a linear motion stage and is movable in the Z-axis direction. The light condensing position moving means 23 is controlled by the light condensing position control means 24, and can control the positional relationship between the light condensing position of the projected light and the plane mirror 14 in the Z-axis direction.

At this time, when the plane mirror 14 is moved by a predetermined distance in the Z-axis direction and the signal level V is taken in while focusing on one of the detection elements of the detector array 11, each movement as shown in FIG. The signal level Vi at the position is plotted. Here, the number of movements i represents the number of movements in the Z-axis direction, and the Z-axis coordinate Zi indicates the position of the plane mirror 14 when the number of movements i has been reached. The peak value Vp is the value of the signal level that was the highest during the movement, and the peak coordinate Zp, which is the Z-axis coordinate of the plane mirror 14 at that time, indicates the height of the plane mirror 14. A peak value detecting means 26 is connected to the detector array 11. The peak value detecting means 26 detects and stores a peak value Vp for each detecting element, and an average value calculating means 27 calculates the sum of the peak values. Is divided by the number of detection elements, an average value can be calculated.

At this time, the detector array position control means 2
2. The focusing position control means 24, the peak value detection means 26, and the average value calculation means 27 may be constituted by individual electronic circuits, respectively, or by individual computer devices (for example, microcomputers). Is also good. Alternatively, the configuration may be such that these functions are realized by one computer device.

FIG. 3 is a flowchart showing an example of the procedure of moving the plane mirror 14 by the light condensing position moving means 23 and detecting the peak value of each detecting element. First, the plane mirror 14 is moved to the initial position (for example, by the focusing position moving means 23).
(The maximum position in the minus direction of the Z axis), and the number of movements i, the peak value Vp, and the peak coordinates Zp are initialized (step S1). From here, the plane mirror 14 is moved in the Z-axis plus direction by a predetermined distance, and the signal level Vi of each detection element and the Z-axis coordinate Zi are fetched into a memory provided in the peak value detection means 26 (step S2). At this time, the focusing position moving means 2
When 3 has a pulse motor, it can be moved by a moving distance by sending a predetermined pulse. This signal level Vi is compared with the peak value Vp (step S3). If the signal level Vi is higher than the peak value Vp, the peak value Vp is updated to the current signal level Vi, and the peak coordinates Z
p is updated to the current Z-axis coordinate Zi (step S4). If the signal level Vi is equal to or less than the peak value Vp in step S3, the process proceeds to step S5.

Thereafter, the number of times of movement i is incremented (step S5), and then the number of times of movement i is compared with a predetermined set value n (step S6). It is determined that the step has not been completed yet, and the process returns to step S2. Step S6
When the number of times of movement i becomes equal to the set value n, all the steps are ended (step S7). Through the above procedure, the peak value Vp is detected.

At this time, in order to ensure the accuracy of the peak value detection, the peak value Vp obtained by the above flow is not simply used as the final peak value at the time of peak value detection. Coordinates (Zp-1, Vp-1), (Z
(p, Vp), (Zp + 1, Vp + 1), a more accurate peak value may be obtained by performing a quadratic curve approximation, or disclosed by the applicant in Japanese Patent Application No. 9-82791 (not disclosed). As described above, the peak value may be obtained by calculating the correlation coefficient.

The peak value Vp for each of the detection elements is all added by the average value calculation means 27 to obtain the sum ピ ー ク Vp of the peak values, and this is divided by the number of the detection elements to obtain the average value Vav.

Next, a method of aligning the detector array using the average value Vav as an index will be described with reference to a flowchart shown in FIG. First, the movement in the Z-axis direction will be described. The detector array 11 is moved to the initial position (for example, the maximum position in the minus direction of the Z-axis) by the detector array moving means 21, and the maximum value Vav of the average value Vav is obtained.
M is initialized (cleared to zero) (step S11). In this state, an average value Vav is determined based on the peak value Vp for each detection element determined according to the procedure of peak value detection shown in FIG. 3 (step S12), and then the average value Vav and the maximum value VM are calculated. After the comparison (step S13), when the newly obtained average value Vav is larger, the maximum value VM is changed to the average value Va.
v (step S14), and thereafter the detector array 1
1 in the Z-axis plus direction by a predetermined distance (step S1).
5). Returning to step S12, the process of obtaining the average value Vav in the new state is repeated.

If the average value Vav is smaller than the maximum value VM in step S13, the detector array 11 is moved in the negative direction of the Z axis (step S16), and the detector array 11 is aligned in the Z axis direction at this position. Is ended (step S17).

Alternatively, the detector array 11 is moved in the plus direction of the Z-axis over the full stroke of the detector array moving means 21 without determining the magnitude of the average value Vav in step S13, and detection is performed so that the average value Vav becomes maximum. Vessel array 1
1 may be stored, and the detector array 11 may be moved there.

At this time, instead of calculating the average value Vav, the detector array may be moved in a direction in which the sum ΣVp is larger.

Alternatively, instead of calculating the average of the signal levels Vi of all the detection elements, an area 17 including at least two areas 17A to 17D is set on the detector array 11 as shown in FIG. 5, for example. , The average value Vav of the signal levels of the detection elements existing in this area 17.
May be required. Each of the areas 17A to 17D may have at least one detection element.

When the positioning of the detector array 11 in the Z-axis direction is completed, the movement in the Y-axis direction is performed in the same manner as the procedure shown in FIG. 4, and the positioning of the detector array 11 in the Y-axis direction is completed. Then, movement in the θ direction is performed in the same manner as the procedure shown in FIG. This allows the detector array 11
Has been aligned in all of the Z, Y, and θ directions. In order to further improve the accuracy at this time, the alignment in the Z, Y, and θ directions may be repeated a predetermined number of times.

Alternatively, the detector array 1 in which the average value Vav becomes the maximum based on the data in all the Z, Y, and θ axis directions.
1 may be determined, and the detector array 11 may be moved to that position.

According to the present embodiment, the condensing position of the projected light is moved and the position of the detector array 11 is adjusted based on the peak value of the signal level in each detecting element. Even if the arrangement is slightly shifted, the signal level at the time of focusing can be obtained, and the alignment can be performed easily and accurately.

Further, an average value of the peak values is calculated,
Since the alignment of the detector array 11 is performed so as to maximize this, even if the signal level varies due to the inclination of the plane mirror 14 or the characteristics of the individual detection elements, the optimum alignment as a whole can be performed. it can.

Further, since the numerical data of the average value is used as an index for the positioning, if the detector array 11 is moved in a higher direction to perform the positioning,
Positioning can be performed based only on simple arithmetic processing. Therefore, by executing this arithmetic processing by a computer device or the like, the positioning can be adjusted with high accuracy regardless of the skill level of the operator and individual differences, and automation is easy.

Here, in this embodiment, the plane mirror 14 is used.
However, the work 8 may be installed to perform positioning. This is because the focusing position is moved up and down with respect to the work 8 by the focusing position moving means 23 and the peak value at the time of focusing is detected. This is because only the intensity can be detected and the alignment is performed based on the value.

According to this, since there is no need to re-install the plane mirror at the time of positioning, it is possible to save the labor of positioning and to always prepare a plane mirror which is not used for normal measurement. In addition, when the alignment is performed by using the plane mirror 14, the reflected light may become stronger than in the normal measurement and may exceed the dynamic range of the detection element. There is no sex. Of course, any object other than the work 8 and the plane mirror 14 may have an equivalent reflectance to the projected light.

Next, a second embodiment will be described with reference to FIG. FIG. 6 shows a confocal optical device according to the present embodiment, and the confocal optical system is the same as that shown in FIG.

The light-receiving pinhole array 9 is moved by the light-receiving pinhole array moving means 28 which is a combination of a pulse motor, a direct-acting stage and a rotary stage, for example, as shown in FIG.
It is movable in the Y and θ directions, and its position in the Z and Y directions and the angle in the θ direction are controlled by the output from the light receiving pinhole array position control means 29. In this case, the work 8 is set at the light condensing position, and the alignment is performed by the reflected light of the work 8.

Hereinafter, the procedure of the alignment in this embodiment will be described. First, in a state where the light receiving pinhole array 9 is not installed, the positioning of the detector array 11 is performed by the procedure shown in FIGS. After the positioning of the detector array 11 is performed in this manner, the light receiving pinhole array 9 is set at a predetermined position, and
The position of the light receiving pinhole array 9 may be adjusted as in the case of (1).

As a result, the same functions and effects as those of the above embodiment can be obtained, and not only the detector array 11 but also the light receiving pinhole array 9 can be precisely and repeatedly aligned.

Next, a third embodiment will be described with reference to FIGS. FIG. 7 is an explanatory view showing an exposure state of a hologram in a confocal optical device using a hologram. A light source 41 is a light source that emits coherent light such as a laser, and light emitted from the light source 41 is emitted by a beam splitter 42. The light that has been split and travels straight is reflected obliquely upward and leftward in the figure by a mirror 43D, is enlarged by lens groups 44A and 44B, and is applied to a hologram 47 as reference light 46.

The light reflected rightward in the figure by the beam splitter 42 is reflected by mirrors 43A, 43B, 43C, expanded by lens groups 48A, 48B, and radiated to a pinhole array 49. Here, the pinhole array 49 is the light projection pinhole array 3 in the above embodiment.
The light having passed through the hologram 47 becomes the plurality of light sources 4 and enters the lens group 50A, where it is shaped in parallel, and becomes the object light 51 and enters the hologram 47. The hologram 47 is exposed by the reference light 46 and the object light 51.

FIG. 8 shows a configuration of the confocal optical device using the hologram 47 when measuring the work 8. When the hologram 47 is illuminated with the same reference beam 46 as during the exposure, the object beam 51 is reproduced from the hologram 47 downward in the figure by diffraction of light. This is condensed by the lens group 50B and is projected on the work 8. The light reflected by the work 8 is divided into the lens group 50B, the hologram 47, and the lens group 5
0A is transmitted in the direction opposite to the outward path, and is focused on the pinhole array 49.

Here, the pinhole array 49 performs the same operation as the light receiving pinhole array 9 in the above embodiment, and when the light projected and focused on the work 8 is in a focused state. Allows most of the light to pass through and reduces the light passing through when out of focus. The light passing through the pinhole array 49 is condensed and incident on the detector array 53 by the relay lens groups 52A and 52B, and the intensity thereof is detected.

At this time, by moving the lens group 50B in the Z-axis direction in the figure, the light condensing position of the light projected on the work 8 can be changed. The lens group 50B is attached to the focusing position moving means 23, and the focusing position moving means 23 is driven in accordance with a command from the focusing position control means 24 to control the focusing position. As described above, the surface shape of the work 8 can be measured by changing the condensing position of the light projected on the work 8 and detecting the intensity of the light whose reflected light passes through the pinhole 49.

The positioning of the detector array 53 is performed by installing the work 8 or the plane mirror 14 as described above. The detector array 53 can be moved and rotated in the X, Y, and φ directions in the figure by the detector array moving means 21.

A peak value detecting means 26 is connected to the detector array 53 in the same manner as in the above-described embodiment, and the peak value detecting means 26 applies a peak value to each detecting element according to the procedure shown in FIG. The average value Vav can be calculated by detecting and storing Vp, and dividing the sum of the detected peak values Vp by the number of detection elements by the average value calculating means 27.

The peak value Vp detected by the peak value detecting means 26 and the average value Vav calculated by the average value calculating means 27 are input to a frequency calculating means 31, and this frequency calculating means 31 The peak value Vp is equal to the average value Va.
Count the number of detection elements that fall within a predetermined range set in advance around v.

FIG. 9 is a flowchart showing an example of the procedure for counting the number. Here, the number of detection elements for which the average value is obtained is m, and each detection element is numbered j from 1 to m. A range width defining a predetermined range centered on the average value Vav is defined as ΔVav.

First, the counter k is initialized to 0 and the detection element number j is initialized to 0 (step S31), and the peak value Vpj of each detection element is changed from (Vav-ΔVav) to (Vav + ΔVav).
Is determined (step S32), and if so, the counter k is incremented by 1 (step S33). Step S3
2, the peak value Vpj changes from (Vav−ΔVav) to (Vav + ΔV).
If not, the process proceeds to step S34.

Next, the number j is incremented by one, and it is determined whether or not the number j exceeds the number m of the detecting elements (step S35). The above processing is repeated from step S32 until the number j exceeds the number m. Yes (Step S3
6). By this processing, the counter k indicates the number of detection elements whose peak value Vp is within the above-mentioned predetermined range, and this is hereinafter referred to as a frequency.

FIG. 10 shows a procedure for positioning the detector array 53 in the present embodiment, which will be described with reference to FIG. First, the movement in the X-axis direction will be described.
The detector array 53 is moved by the detector array moving means 21.
Is moved to the initial position (for example, the maximum position in the minus direction of the X-axis), and the frequency calculating means 31 initializes the maximum value VM of the average value Vp and the maximum frequency KM which is the maximum value of the frequency (step S21). In this state, the peak value detecting means 26 calculates the average value Vav in accordance with the procedure of peak value detection and average value detection shown in FIGS. 3 and 4, and based on the detection result, the frequency count shown in FIG. The frequency k is obtained according to the procedure (step S22). At this time, the value of Vav is
For example, the numerical value is rounded off by rounding to the smallest digit (step S23).

Next, the rounded average value Vav is compared with the maximum value VM (step S24). If the newly obtained average value Vav is equal to or greater than the maximum value VM, the maximum value VM is updated to the average value Vav (step S24). S25) The detector array 53 is moved a predetermined distance in the X-axis plus direction (Step S26), and Step S2 is performed.
Returning to 2, the average value Vav and the maximum value V in the new state
Repeat asking for M.

In step S24, the average value Vav
Is smaller than the maximum value VM, the detector array 53 is set to X
It moves in the axis minus direction (step S27), and the alignment of the detector array 53 in the X-axis direction ends at this position (step S28).

In step S24, the average value Vav
Is equal to the maximum value VM, the frequency k obtained in step S22 is compared with the maximum frequency KM (step S29).
If the frequency k is greater than the maximum frequency KM, the maximum frequency KM is
(Step S30), and returns to step S26 to determine the average value Vav in the new state. If the frequency k is equal to or greater than the maximum frequency KM, the process shifts to step S28 and ends.

When the positioning of the detector array 53 in the X-axis direction is completed, the movement in the Y-axis direction is performed in the same manner as the procedure shown in FIG. 10, and the positioning of the detector array 53 in the Y-axis direction is completed. Then, rotation in the φ direction is performed in the same manner as the procedure shown in FIG. This allows the detector array 5
3 has been aligned in all of the X, Y, and φ directions. In order to further improve the accuracy at this time,
The alignment in the X, Y, and φ directions may be repeated a predetermined number of times.

As described above, when the amount of change in the average value does not exceed a predetermined value even when the detector array 11 is moved, that is, when the average value hardly changes, the signal of each detection element is changed. By performing positioning so that the level is as close to the average value as possible, it is possible to perform more precise positioning than using only the average value as an index.

In the above embodiment, the minimum digit is rounded off as in step S23 to determine that the average value hardly changes even when the detector array 11 is moved. Are moved in the X, Y, and φ directions over the full stroke of the detector array moving means 21, and the average value Vav, the maximum value Vp, the frequency k, and the maximum frequency KM at all the locations are obtained and stored. If the average value Vav falls within a range between the maximum value Vp and a value (Vp-ΔVp) lower than the maximum value Vp by a predetermined value ΔVp,
The detector array 11 may be moved to a place where the frequency k becomes the maximum frequency KM.

As described above, according to the present invention, the position of the detector array 11 is adjusted using the signal level of the detecting element at the time of focusing as an index, so that the surface of the plane mirror 14 is distorted or the optical axis Can be aligned even if it is not placed perpendicularly to the work, and the plane mirror 14 does not necessarily have to be used, and the work 8 actually measured
Positioning can be performed even when the device is installed.

Further, according to the present invention, the average value of the signal levels output from the respective detection elements or the frequency representing the variation of the signal levels output from the respective detection elements is used as the index of the alignment, so that the work is carried out. Positioning can be performed with high accuracy regardless of the skill level or individual difference of the person, no skill is required, and it is possible to respond to automation. For example, if the confocal optical device is aligned at the start of the first day of the day, the measurement accuracy of the device can be increased.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a confocal optical device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a relationship between a movement amount of a light-converging position and an output of a detection element.

FIG. 3 is a view for explaining an example of a flowchart showing a procedure of peak value detection.

FIG. 4 is a view for explaining an example of a flowchart showing a procedure for performing alignment of a detector array based on an average value of peak values.

FIG. 5 is an explanatory diagram of an area set on a detector array.

FIG. 6 is a configuration diagram of a confocal optical device according to a second embodiment.

FIG. 7 is a diagram illustrating a hologram exposure method of a confocal optical device using a hologram.

FIG. 8 is a configuration diagram of a confocal optical device using a hologram according to a third embodiment.

FIG. 9 is a view for explaining an example of a flowchart showing a procedure for obtaining a frequency.

FIG. 10 is a view for explaining an example of a flowchart showing a procedure for positioning a detector array according to the third embodiment.

FIG. 11 is a configuration diagram of a conventional confocal optical device including a plurality of light sources and a detector array.

FIG. 12 is a configuration diagram of a conventional confocal optical device including a plurality of light sources and a detector array.

FIG. 13 is an explanatory diagram of alignment of a conventional confocal optical device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 light source 2 lens 3 light emitting pinhole array 4
... multiple light sources, 6A, 6B ... lens group, 8 ... work, 9
... Light receiving pinhole array, 10 ... predetermined object, 11 ... detector array, 14 ... plane mirror, 17 ... area on detector array, 21 ... detector array moving means, 22 ... detector array position control means, 23 ... Focusing position moving means, 24 Focusing position control means, 26 Peak value detecting means, 27 Average value calculating means, 28 Light receiving pinhole array moving means, 29
... Light receiving pinhole array position control means, 31... Power calculating means, 41... Light source, 44 A, 44 B.
Hologram, 48A, 48B: lens group, 49: pinhole array, 50A, 50B: lens group, 52A, 52
B: lens group, 53: detector array.

Claims (9)

[Claims] A plurality of light sources (4) projected on a predetermined object (8, 14); and a plurality of light sources (4) projected on the predetermined object (8, 14). A light-converging position of the emitted light, a light-condensing position moving means (23) for moving the light in the optical axis direction of the light, and an intensity of light reflected by the predetermined object (8, 14). In a confocal optical device comprising a detector array (11) having a plurality of detection elements for detecting, the detector array (11) at least with respect to a plane optically conjugate with the plurality of light sources (4). Detector array moving means (21) for performing either parallel movement or rotation
And detecting a peak value of a signal level output from at least two of the detection elements on the detector array (11) for each of the detection elements when the condensing position of the projected light is moved. A peak value detecting means (26), based on the peak value, the detector array moving means (2
A confocal optical device comprising: a detector array position control means (22) for controlling a position of the detector array (11) by outputting a movement command to (1). 2. A plurality of light sources (4) projected on a predetermined object (8, 14); and a plurality of light sources (4) projected on the predetermined object (8, 14). A condensing position moving means (23) for moving a condensing position of the emitted light in the optical axis direction of the light, a light receiving pinhole array (9) having a plurality of openings, A detector array (11) having a plurality of detection elements for detecting the intensity of light that has passed through the opening of the light-receiving pinhole array (9) out of the reflected light reflected by the predetermined object (8, 14). A confocal optical device comprising: a light-receiving pin for moving or rotating the light-receiving pinhole array (9) at least in parallel with a plane optically conjugate with the plurality of light sources (4); A hole array moving means (28), and at least two of the detecting elements on the detector array (11) when the condensing position of the projected light is moved. A peak value detecting means (26) for detecting a peak value of each signal level of the signal level outputted from the detecting element, and a movement command to the light receiving pinhole array moving means (28) based on the peak value. Light receiving pinhole array
A confocal optical device comprising: a light receiving pinhole array position control means (29) for controlling the position of (9). 3. The confocal optical device according to claim 1, wherein an average value calculating means for calculating an average value of the peak values obtained for at least two detection elements on the detector array (11). (27) attached, the detector array position control means (22) outputs a movement command to the detector array moving means (21), the position of the detector array (11) to the larger average value Confocal optical device characterized by controlling the following. 4. The confocal optical device according to claim 2, wherein an average value calculating means for calculating an average value of the peak values obtained for at least two detection elements on the detector array (11). 27), the light receiving pinhole array position control means (29) outputs a movement command to the light receiving pinhole array moving means (28),
A confocal optical device, wherein the position of the light receiving pinhole array (9) is controlled to the one with the larger average value. 5. The confocal optical device according to claim 3, wherein the number of detection elements is such that the peak value obtained for the at least two detection elements falls within a predetermined range centered on the average value. Frequency calculation means (3
1), the detector array position control means (22) outputs a movement command to the detector array moving means (21), the detector array (11)
The position of the detector array (11) is controlled to the larger average value until the amount of increase of the average value when moving the position does not exceed a predetermined value, and the detector array ( A confocal optical device characterized by controlling the position of 11). 6. The confocal optical device according to claim 4, wherein the number of detection elements such that the peak value obtained for the at least two detection elements falls within a predetermined range centered on the average value. Frequency calculation means (3
1), the light receiving pinhole array position control means (29) outputs a movement command to the light receiving pinhole array moving means (28),
Until the amount of change in the average value when moving the position of the light-receiving pinhole array (9) does not exceed a predetermined value, controlling the position of the light-receiving pinhole array (9) to the larger average value, Light receiving pinhole array (9)
A confocal optical device for controlling the position of the lens. 7. A detection device that emits light from a plurality of light sources (4) to a predetermined object (8, 14) and has a plurality of detection elements at positions optically conjugate with the plurality of light sources (4). A detector array (11) or a light receiving pinhole array (9) in which a plurality of openings are arranged, and the intensity of light reflected by the predetermined object (8, 14) is determined by the detector array (11). Or of a confocal optical device for detecting with a detector array (11) that receives light passing through the opening of the light receiving pinhole array (9), the detector array (11) or the light receiving pinhole array (9) In the positioning method, the condensing position of the projected light is moved in the optical axis direction of the light with respect to a predetermined object (8, 14), and the detector array (11 A) detecting the peak value of each signal level of the signal levels output from at least two of the detection elements, based on the peak value, Out unit array (11) or is characterized in that to carry out the positioning of the light receiving pinhole array (9), a method of aligning the confocal optical system. 8. A detection device that emits light from a plurality of light sources (4) to a predetermined object (8, 14), and has a plurality of detection elements at positions optically conjugate with the plurality of light sources (4). A detector array (11) or a light receiving pinhole array (9) in which a plurality of openings are arranged, and the intensity of light reflected by the predetermined object (8, 14) is determined by the detector array (11). Or of a confocal optical device for detecting with a detector array (11) that receives light passing through the opening of the light receiving pinhole array (9), the detector array (11) or the light receiving pinhole array (9) In the positioning method, the condensing position of the projected light is moved in the optical axis direction of the light with respect to a predetermined object (8, 14), and the detector array (11 ) Detecting the peak value of the signal level output from at least two of the detection elements for each detection element, and calculating the average value of the peak values Said detector array (11) or said light receiving pinhole array
(9) A method of positioning a confocal optical device, wherein the positioning is performed by moving the average value in a higher direction. 9. A detection device that emits light from a plurality of light sources (4) to a predetermined object (8, 14) and has a plurality of detection elements at positions optically conjugate with the plurality of light sources (4). A detector array (11) or a light receiving pinhole array (9) in which a plurality of openings are arranged, and the intensity of light reflected by the predetermined object (8, 14) is determined by the detector array (11). Or of a confocal optical device for detecting with a detector array (11) that receives light passing through the opening of the light receiving pinhole array (9), the detector array (11) or the light receiving pinhole array (9) In the positioning method, the condensing position of the projected light is moved in the optical axis direction of the light with respect to a predetermined object (8, 14), and the detector array (11 ) Detecting the peak value of the signal level output from at least two of the detection elements for each detection element, and calculating the average value of the peak values The number of detection elements whose peak value falls within a predetermined range centered on the average value is counted as a frequency, and the amount of change in the average value when the position of the detector array (11) is moved is a predetermined value. Until the value does not exceed, control the position of the detector array (11) or the light receiving pinhole array (9) to the larger of the average value, the detector array (11) or the A method for positioning a confocal optical device, wherein a position of a light receiving pinhole array (9) is adjusted.