JP7337637B2 - Laser probe and optical adjustment method - Google Patents

Description

The present invention relates to a laser probe that irradiates an object to be measured with laser light and reads the reflected laser light with a line sensor, and an optical adjustment method.

Conventionally, as a laser probe using laser light, there is a laser probe that utilizes the principle of the Scheimpflug optical system. The Scheimpflug optical system is an optical system in which an imaging surface of an imaging device, a main surface of a lens, and an irradiation surface of line laser light intersect on the same straight line.

As a measuring device using the principle of such a Scheimpflug optical system, the object to be measured is irradiated with line light, or the spot light is scanned within a linear range using a scanning unit such as a galvanomirror, and the reflected light is It is known to receive light with a line sensor (see Patent Document 1, for example).
A laser probe (surface inspection device) described in Patent Document 1 includes a light projecting optical system and a light receiving optical system.
The projection optical system includes a DMD (Digital Micro-mirror Device) and a projection lens. The DMD forms linear light (line light) extending along one direction. The light is collimated and radiated onto the object to be measured.
The light-receiving optical system includes a telecentric optical system and a CCD (Charge Coupled Device) configured as a line sensor, and the light from the measurement object transmitted through the telecentric optical system forms an image on the line sensor.
In Patent Document 1, line light is emitted from the posting optical system, but the irradiation direction of the laser spot light may be scanned on the measurement target by swinging using a scanning means such as a galvanomirror (flying spot method).

JP 2007-24623 A

By the way, when the line sensor detects the reflected light of the spot light or line light projected by the flying spot method, which is irradiated to the measurement object, the spot light scanned by the measurement object is reflected and enters the line sensor. It is necessary to adjust the scanning direction of the spot light and the linear direction of the line light so that the line light reflected by the object to be measured is incident on the line sensor.
That is, the line sensor is configured by arranging a plurality of light receiving pixels along the line sensor axis, and the width of the sensor axis (the width in the direction orthogonal to the longitudinal direction) is very narrow. Therefore, when the spot light or line light reflected by the object to be measured is projected onto the plane on which the line sensor is provided, the axis of the projected light (hereinafter referred to as the light projection axis) is aligned with the sensor axis of the line sensor. If tilted, the reflected light cannot be measured correctly by the line sensor.
Therefore, a laser probe using a line sensor requires optical adjustment to align the sensor axis of the line sensor with the light projection axis. However, since the width of the line sensor is very narrow, whether or not the sensor axis of the line sensor and the light projection axis are aligned, and if the axes are misaligned, how much the axis adjustment direction and adjustment amount are. It is difficult to ascertain whether Therefore, the conventional laser probe has the problem that it takes a lot of time for optical adjustment, and skill is required for the adjustment work.

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser probe and an optical adjustment method that can easily align the scanning axis of spot light or the linear axis of line light with the sensor axis of a line sensor.

A laser probe according to the present invention includes a light source unit that irradiates light onto a predetermined linear range on the surface of a measurement object, a line sensor that receives reflected light of the light irradiated onto the linear range, and the line sensor. and an imaging unit that captures an image of the sensor substrate.

According to this configuration, when the light source unit irradiates the linear range of the measurement target with light, an image of the light reflected in the linear range is projected onto the sensor substrate. Further, the imaging unit can capture a captured image including the line sensor, the sensor substrate on which the line sensor is arranged, and the projection light reflected by the linear range of the measurement target. Therefore, based on the captured image, it can be easily confirmed whether or not the sensor axis of the line sensor coincides with the axis of the projection light reflected in the linear range of the measurement target (optical projection axis). Therefore, even an unskilled worker can easily determine whether or not the sensor axis of the line sensor and the light projection axis are appropriately aligned. In addition, since the direction and amount of misalignment between the light projection axis and the sensor axis can be visually recognized based on the captured image, even if the user is not highly skilled, the light irradiation direction of the light source or the line can be detected. The position of the sensor can be adjusted to provide optical alignment of the laser probe.

In the laser probe of the present invention, the light source unit includes a spot light source that emits spot light, reflects the spot light, swings the reflection direction of the spot light, and scans the spot light within the linear range. It is preferable to provide a scanning unit that allows the scanning to be performed.
In the present invention, by changing the reflection direction of the spot light emitted from the spot light source by the scanning unit, the spot light is scanned at high speed in a linear range of the measurement target, so-called flying spot measurement can be performed. can. In such a flying spot method, the scanning unit can freely set the range of the spot light.

An optical adjustment method according to the present invention includes a light source unit that irradiates light onto a predetermined linear range on a surface of an object to be measured, a line sensor that receives reflected light of the light irradiated onto the linear range, and the line sensor. and an imaging unit configured to image the sensor substrate, wherein the imaging unit acquires a captured image by capturing an image of the sensor substrate, and in the captured image , the irradiation direction of the light from the light source unit and the position of the line sensor based on the positional relationship between the reflection position on the sensor substrate of the light reflected in the linear range and the sensor axis of the line sensor; Adjust at least one of
As a result, positional deviation between the light projection axis and the sensor axis can be easily confirmed based on the captured image, and optical adjustment can be easily performed.

1 is a schematic diagram showing a schematic configuration of a measuring device provided with a laser probe according to one embodiment of the present invention; FIG. FIG. 4 is a diagram showing reflection positions of spotlights moving on the sensor substrate of the present embodiment; FIG. 4 is a diagram showing an example of a captured image of a sensor substrate captured by an imaging unit in the embodiment; 4 is a flow chart showing an optical adjustment method for the laser probe according to the present embodiment;

An embodiment according to the present invention will be described below.
FIG. 1 is a schematic diagram showing a schematic configuration of a measuring apparatus 1 equipped with a laser probe 10 of this embodiment.
The measuring device 1 is a three-dimensional measuring device that uses laser light to measure the shape of an object W (measurement target) in a non-contact manner. a moving mechanism 20 for moving the laser probe 10, a control unit 30 for measuring the shape of the object W based on a signal from the laser probe 10, and a display 40 for displaying images such as measurement results.
Each configuration will be described in detail below.

[Configuration of Laser Probe 10]
The laser probe 10 includes a laser irradiation optical system 110 (light source section) and a light receiving optical system 120, as shown in FIG.
The laser irradiation optical system 110 includes a laser light source 111 , a reflecting mirror 112 and a scanning section 113 .
The laser light source 111 is a spot light source that emits a point laser (hereinafter referred to as spot light).
Reflecting mirror 112 reflects the spot light emitted from laser light source 111 toward scanning unit 113 .
The scanning unit 113 is composed of, for example, a galvanometer mirror, a resonant mirror, or the like, and swings the reflection direction of the spot light reflected by the reflection mirror 112 along the same plane. As a result, since the irradiation direction of the spot light irradiated onto the object W moves along the same plane, the irradiation position of the spot light on the surface of the object W also moves along the straight line direction. That is, the surface of the object W is scanned with the spot light in a linear range W0 along the linear direction.
Here, an example in which the spot light reflected by the reflecting mirror 112 is reflected within the linear range W0 of the object W by the scanning unit 113 is shown. A configuration may also be adopted in which the light enters the scanning unit 113 without being exposed and is reflected in the linear range W0 of the object W. FIG.

The light receiving optical system 120 includes an imaging lens 121 , a sensor substrate 122 , a line sensor 123 and an imaging section 124 .
The imaging lens 121 forms an image of the spot light reflected by the linear range W0 of the object W on the sensor substrate 122 .
The sensor substrate 122 is a substrate on which the line sensor 123 is arranged. The sensor substrate 122 has a substrate surface whose surface facing the imaging lens 121 is flat. For example, the line sensor 123 is arranged at the center of the substrate surface.

The line sensor 123 is a light-receiving sensor elongated along a sensor axis 123A (see FIG. 2), and a plurality of photoelectric conversion elements are arranged along the sensor axis 123A. For example, a line sensor 123 is used in which photoelectric conversion elements of one pixel in the width direction perpendicular to the sensor axis 123A and thousands of pixels in the axial direction along the sensor axis 123A are arranged. In this case, the width of the line sensor 123 is the width of the photoelectric conversion element of one pixel, which is several μm.
The imaging unit 124 is an image sensor that captures an image of the substrate surface of the sensor substrate 122 including the line sensor 123 , and outputs the captured image of the substrate surface to the control unit 30 . Note that the imaging unit 124 may be provided detachably with respect to the laser probe 10 .

Here, the laser probe 10 of this embodiment constructs a Scheimpflug optical system. That is, as shown in FIG. 1, the plane including the irradiation surface (linear range W0) of the spot light scanned by the scanning unit 113, the main surface of the imaging lens 121, and the sensor substrate 122 on which the line sensor 123 is provided. The optical system is constructed such that it intersects with the substrate surface on the same straight line.

[Configuration of moving mechanism 20]
The moving mechanism 20 is a device that moves the laser probe 10 to an arbitrary position. Further, the moving mechanism 20 is provided with a position detection sensor (not shown) for detecting the position of the laser probe 10 .
A specific configuration of the moving mechanism 20 is not particularly limited, and for example, a configuration in which the laser probe 10 is held at the tip of a multi-joint arm and the angle of each arm of the multi-joint arm can be changed may be employed. In this case, an angle detection sensor such as a rotary encoder is provided to detect the rotation angle of each arm. Thereby, the control unit 30 can calculate the position and orientation of the laser probe 10 based on the arm length of each arm and the angle between the arms.
Further, the moving mechanism 20 may be configured to be held by a portal frame that moves the laser probe 10 in the XYZ directions. That is, the moving mechanism 20 includes a column that can move in the Y direction, a beam that is held by the column and parallel to the X direction, a slider that can move on the beam in the X direction, and a slider that moves in the Z direction. A movable head holding member may be provided, and the laser probe 10 may be held by the head holding member. In such a configuration, the moving mechanism 20 includes a Y scale for detecting the position of the column in the Y direction, an X scale for detecting the position of the slider in the X direction, and a Z scale for detecting the position of the head holding member in the Z direction. configuration. Thereby, the XYZ coordinates of the laser probe 10 can be detected. An angle changing portion for changing the angle of the laser probe 10 may be provided in the head holding member. In this case, the posture of the laser probe 10 can be detected by providing an angle detection sensor in the angle changing portion.

[Configuration of control unit 30]
The control unit 30 is configured by a computer, and includes a memory (not shown), an arithmetic circuit that executes various programs recorded in the memory, and the like. The control unit 30 is connected to the laser probe 10 and the moving mechanism 20, and based on the light receiving result of the line sensor 123 of the laser probe 10 and the position and orientation of the laser probe 10 output from the moving mechanism 20, to measure the shape of the object W. Also, the control unit 30 outputs the captured image of the imaging unit 124 to the display 40 . Accordingly, the operator can easily confirm whether or not the spot light reflected by the linear range W0 of the object W is imaged on the line sensor 123 of the sensor substrate 122. FIG.

Specifically, the control unit 30 functions as a probe control unit 31, a probe position detection unit 32, a shape calculation unit 33, and an image output unit 34, as shown in FIG.
The probe control unit 31 performs lighting control of the laser light source 111 of the laser probe 10, scanning control of the scanning unit 113, reception control of measurement signals from the line sensor 123, imaging control of the imaging unit 124, and the like.
The probe position detection unit 32 receives position detection results (for example, detection values of an angle detection sensor such as a rotary encoder or XYZ scale detection values) input from the position detection sensor of the moving mechanism 20 . Then, the probe position detection unit 32 calculates the position and orientation of the laser probe 10 in the three-dimensional space based on the position detection result.

The shape calculator 33 measures the surface shape and surface properties of the object W based on the light reception result output from the line sensor 123 and the position and orientation of the laser probe 10 detected by the probe position detector 32. do. That is, the line sensor 123 sequentially measures the reflection position of the spot light reflected in the linear range W0 of the object W. FIG. The shape calculator 33 calculates the shape of the object W based on the reflection position of the spot light received by the line sensor 123, for example, using a triangulation method or the like.

The image output unit 34 outputs the captured image captured by the imaging unit 124 to the display 40 . In the captured image of the substrate surface of the sensor substrate 122 captured by the imaging unit 124, the position of the line sensor 123 on the sensor substrate 122 and the reflection position of the spot light reflected in the linear range W0 are captured. By scanning the spot light at high speed over the linear range W0, the trajectory of the reflection position of the spot light on the sensor substrate 122 is imaged by the imaging unit 124, and a straight line (light projection axis Q) corresponding to the linear range W0 is captured. appears in the image as

FIG. 2 is a diagram showing reflection positions of spotlights moving on the sensor substrate 122, and FIG.
FIG. 3 shows a diagram in which captured images are superimposed when captured images are acquired at a predetermined cycle. As shown in FIG. 2, the reflection position q of the spot light moves along the light projection axis Q on the sensor substrate 122 . Therefore, when a plurality of captured images are superimposed, the trajectory of the reflection position q of the spot light, which indicates the light projection axis Q, appears in the image as shown in FIG.
In order to accurately and accurately measure the shape of the object W with the laser probe 10, the light projection axis Q should coincide with the sensor axis 123A of the line sensor 123 and be positioned on the line sensor 123. , alignment (optical adjustment) must be performed.
In this embodiment, the image output unit 34 causes the display 40 to display a captured image as shown in FIG. This allows the operator to easily recognize the deviation between the scanning direction of the spot light on the laser probe 10 and the sensor axis 123A of the line sensor 123. FIG. Further, based on the captured image, the deviation direction and deviation amount (angle) between the scanning direction of the spot light and the sensor axis 123A of the line sensor 123 can be easily corrected.

[Optical adjustment method]
Next, an optical adjustment method for the laser probe 10 in the measuring apparatus 1 as described above will be described.
FIG. 4 is a flowchart showing an optical adjustment method for the laser probe 10 of this embodiment.
In the laser probe 10, as described above, the scanning direction of the spot light, that is, the reflection position on the sensor substrate 122 of the reflected light reflected in the linear range W0 of the object W, and the sensor axis 123A of the line sensor 123. , optically adjusted to match.
For this, first, the laser probe 10 is moved to a position facing the object W (step S1). Object W may be a reference calibration object having a calibration surface that is a flat surface.
Then, the probe control unit 31 controls the laser light source 111 to emit a spot light, and the scanning unit 113 swings the reflection direction of the spot light within the same plane to illuminate the object by a flying spot method. W is irradiated (step S2). As a result, the object W is scanned in the linear range W0 with the spot light.

Next, the probe control section 31 controls the imaging section 124 to capture an image of the sensor substrate 122 and acquires a captured image (step S3). Further, the image output unit 34 causes the display 40 to display the captured image captured in step S3 (step S4).
In steps S3 and S4, the image output unit 34 causes the display 40 to sequentially display captured images captured at a predetermined frame rate in the cycle, thereby displaying the captured image of the sensor substrate 122 as a moving image on the display 40. You may let
Further, the image output unit 34 superimposes a plurality of captured images captured at predetermined intervals to generate an image including the trajectory of the reflection position q along the light projection axis Q as shown in FIG. 3 and display the image. 40 may be displayed.
Furthermore, when the scanning speed of the scanning unit 113 is sufficiently fast with respect to the shutter speed of the imaging unit 124, a captured image obtained by one imaging process may be displayed. In this case, the image output unit 34 may cause the display 40 to display the captured image obtained by imaging as it is.

After that, based on the captured image of the sensor substrate 122 displayed on the display 40, the operator adjusts the line so that the sensor axis 123A of the line sensor 123 and the light projection axis Q, which is the trajectory of the spot light, coincide with each other. At least one of the arrangement position of the sensor 123 and the scanning direction of the spot light by the scanning unit 113 is adjusted, that is, the optical adjustment of the laser probe 10 is performed (step S5).
For example, when a galvanomirror is used as the scanning unit 113, the tilt of the rotation axis of the galvanomirror and the arrangement position of the galvanomirror are finely adjusted to adjust the scanning direction of the spot light, and the light projection axis Q is adjusted. , the sensor axis 123 A of the line sensor 123 .
Further, when adjusting the position of the line sensor 123 or the sensor substrate 122, finely adjust the arrangement position of the line sensor 123 or the sensor substrate 122 so that the line sensor 123 overlaps the light projection axis Q. FIG.
In addition, when the imaging unit 124 is detachably provided with respect to the laser probe 10 , the imaging unit 124 may be removed from the laser probe 10 after performing the optical adjustment processing as described above.

[Action and effect of the present embodiment]
The measuring apparatus 1 of this embodiment includes a laser probe 10 , and the laser probe 10 includes a laser irradiation optical system 110 and a light receiving optical system 120 . The laser irradiation optical system 110 includes a laser light source 111 that emits spot light, a spot light that reflects the spot light, changes the direction of reflection of the spot light, and emits a spot within a predetermined linear range W0 on the surface of an object W (measurement object). and a scanning unit 113 for scanning light. The light-receiving optical system 120 includes a line sensor 123 that receives the reflected light of the light applied to the linear range W0, a sensor substrate 122 provided with the line sensor 123, and an imaging unit 124 that images the sensor substrate 122. .

In the laser probe 10 of this embodiment, when the laser irradiation optical system 110 irradiates the spot light onto the linear range W0 of the object W, an image of the spot light reflected in the linear range W0 is projected onto the sensor substrate 122. be. Therefore, by capturing an image of the sensor substrate 122 with the imaging unit 124, it is possible to determine whether or not the light projection axis Q, which is the trajectory of the reflected position of the spot light, and the sensor axis 123A of the line sensor 123 match the captured image. can judge. Also, based on the captured image, the direction, angle, and amount of positional deviation between the light projection axis Q and the sensor axis 123A can be easily confirmed. Therefore, the operator can optically adjust the laser probe 10 without requiring high skill.

In addition, in the laser probe 10 of the present embodiment, the laser irradiation optical system 110 includes a laser light source 111 that emits spot light, and the spot light is scanned within a linear range W0 of the object W by swinging the reflection direction of the spot light. and a scanning unit 113 that causes the image to be scanned.
As a result, in the present embodiment, measurement can be performed by a so-called flying spot method in which the spot light is scanned at high speed in the linear range W0. In such a measuring device 1, the scanning range and scanning speed can be freely set by the scanning unit 113. FIG.

[Modification]
It should be noted that the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.
For example, in the above-described embodiment, the laser irradiation optical system 110 has a configuration in which the scanning unit 113 scans the spot light within the linear range W0. On the other hand, the laser probe 10 may be configured to include a line light source that irradiates the linear range W0 with line light. Even when such a line light source is used, the line light reflected by the object to be measured is imaged on the sensor substrate 122 as a projection image having the light projection axis Q on a straight line. Therefore, by capturing an image of the sensor substrate 122 using the imaging unit 124, it is possible to confirm the positional relationship between the light projection axis Q of the line light and the sensor axis 123A of the line sensor 123 from the captured image.

In the measuring device 1 of the above embodiment, the image output unit 34 is configured to display the captured image captured by the imaging unit 124 on the display 40 . In this case, the operator checks the positions of the light projection axis Q and the sensor axis 123A based on the captured image displayed on the display 40, and determines whether or not optical adjustment is necessary.
On the other hand, the control unit 30 of the measurement device 1 may function as a position evaluation unit that evaluates the positional relationship between the light projection axis Q and the sensor axis 123A based on the captured image. For example, the position evaluation unit detects the sensor substrate 122 from the captured image and identifies the position of the line sensor 123 provided at a known position with respect to the sensor substrate 122 . Also, the position evaluation unit applies an edge detection filter or the like to the captured image to detect the position of the spot light (optical projection axis Q). Then, the position evaluation section evaluates whether or not the sensor axis 123A of the line sensor 123 and the light projection axis Q match. For example, it is determined whether or not the ratio of the area where the line sensor 123 overlaps with the trajectory of the central portion where the light amount is equal to or greater than a predetermined value in the light amount distribution of the spot light and the area with the line sensor 123 is equal to or greater than a threshold value.
This eliminates the need for the operator to determine whether or not the sensor axis 123A and the light projection axis match, thereby reducing the burden associated with optical adjustment. In addition, since the position evaluation section may perform the optical adjustment so that the sensor axis 123A and the light projection axis Q are determined to match, even if the operator has low skill, the optical adjustment can be performed with high accuracy. can be done.

Also, the laser probe 10 may include a sensor adjustment actuator that finely adjusts the position and orientation of the sensor substrate 122 . Alternatively, the laser probe 10 may include a mirror actuator that finely adjusts the tilt of the rotation axis of the galvanomirror (resonant mirror) that constitutes the scanning unit 113 and the position of the scanning unit 113 .
In this case, the control section 30 may function as a position evaluation section and a position adjustment section. That is, the position evaluation unit determines whether or not the sensor axis 123A and the light projection axis Q match as described above. When the position evaluation unit determines that the sensor axis 123A and the light projection axis Q are misaligned, the position adjustment unit determines the amount of misalignment between the sensor axis 123A and the light projection axis Q based on the captured image. The angle is calculated, and at least one of the sensor adjustment actuator and the mirror actuator is controlled to automatically adjust the scanning direction of the spot light by the scanning unit 113 or the position of the line sensor 123 . As a result, the work of optical adjustment by the operator can be reduced.

INDUSTRIAL APPLICABILITY The present invention can be applied to a measuring apparatus that irradiates a predetermined linear range of an object with light and receives the light reflected in the linear range with a line sensor.

DESCRIPTION OF SYMBOLS 1... Measuring apparatus 10... Laser probe 30... Control part 34... Image output part 40... Display 110... Laser irradiation optical system 111... Laser light source 112... Reflecting mirror 113... Scanning part 120... Light receiving Optical system 121 Imaging lens 122 Sensor substrate 123 Line sensor 123A Sensor axis 124 Imaging section Q Optical projection axis W Object (object to be measured) W0 Linear range.

Claims (3)

a light source unit that irradiates light to a predetermined linear range on the surface of the object to be measured;
a line sensor for receiving reflected light of the light irradiated in the linear range;
a sensor substrate provided with the line sensor;
an imaging unit that captures an image of the sensor substrate;
a control unit;
with
The control unit controls a captured image captured by the imaging unit, the captured image including a reflection position on the sensor substrate of the light reflected in the linear range and a sensor axis of the line sensor. to appear on the display,
A laser probe characterized by: The laser probe of claim 1, wherein
The light source unit
a spot light source that emits spot light;
a scanning unit that reflects the spot light and swings the reflection direction of the spot light to scan the spot light within the linear range;
A laser probe comprising: a light source unit that irradiates light onto a predetermined linear range on the surface of a measurement object; a line sensor that receives reflected light of the light irradiated onto the linear range; a sensor substrate provided with the line sensor; and the sensor substrate. An optical adjustment method for a laser probe, comprising:
obtaining a captured image by capturing an image of the sensor substrate by the imaging unit;
Based on the positional relationship between the reflection position on the sensor substrate of the light reflected in the linear range and the sensor axis of the line sensor in the captured image, the irradiation direction of the light from the light source unit and the An optical adjustment method characterized by adjusting at least one of the positions of a line sensor.

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