JP2005017257A - Optical measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical measuring device capable of measuring accurately an angle and a distance of a measured object. <P>SOLUTION: In this optical measuring device, an inclination is measured by an autocollimation method, a picture element having the maximum luminous energy is determined as a light convergence spot position, based on an image pick-up signal Sc from an angle measuring image pick-up element 12, and a direction of the inclination and an inclination angle are calculated based on a reference position on an image pick-up face, a distance of the light convergence spot position and a direction thereof. In distance measurement, an inclination is measured at first, and an angle of a work W is detected based thereon. In the device, the picture element having the maximum luminous energy is determined as a light image on the basis of an image pick-up signal Sd from a distance measuring image pick-up element 22, is corrected based on an inclination calculated by the inclination measurement, and the distance of the work W is calculated based on a distance between a position represented by the light image and the reference position, and a direction therein. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical measurement apparatus for detecting the displacement and inclination of an object to be measured.
[0002]
[Prior art]
Patent documents 1 and patent documents 2 are indicated as an optical measuring device which measures the distance and inclination of a measured object.
Among these, the thing of patent document 1 measures the distance and inclination of a to-be-measured object using the principle of a triangulation, and is provided with the optical system for distance measurement, and the optical system for inclination measurement. In the displacement measuring optical system, the light from the light projecting element converged by the lens is projected obliquely onto the object to be measured, and the reflected light is converged by the lens to form an image on the imaging surface of the imaging means. The distance of the object to be measured can be measured from the imaging position on the imaging surface.
In addition, the tilt measurement optical system projects light from the light projecting element, which has been collimated by the lens, onto the object to be measured from an oblique direction, and the reflected light is converged by the lens to be connected to the imaging surface of the imaging means. The inclination of the object to be measured can be measured based on the imaging position on the imaging surface.
[0003]
On the other hand, in Patent Document 2, the object to be measured is irradiated with the light from the light projecting element, the diffuse reflected light from the object to be measured collected by the lens is received by the displacement measuring imaging means, and The reflected light is reflected by a prism and received by an inclination measuring imaging means. Thereby, the displacement of the measurement object is measured based on the light irradiation position in the displacement measurement imaging means, and the inclination of the measurement object is measured based on the light irradiation position in the inclination measurement imaging means. It is.
[0004]
[Patent Document 1]
JP-A-8-240408
[Patent Document 2]
Japanese Patent Laid-Open No. 11-153407
[0005]
[Problems to be solved by the invention]
By the way, in the apparatus of the above-mentioned patent document 1, since both the distance measurement and the angle measurement use the principle of triangulation, the irradiation position of the light projected from the light projecting element according to the distance of the object to be measured. That is, the measurement position is shifted. In particular, since the angle measurement is also applied to two-surface detection that measures the relative angle between two types of objects to be measured, in such a case, the relative angle between the two surfaces cannot be measured accurately. . On the other hand, by irradiating the light from the light projecting element in the direction along the displacement direction of the object to be measured, the displacement of the measurement point can be eliminated. Since the optical system for operation is arranged on the same axis, the distance cannot be measured.
In addition, the object to be measured has various materials and the like, and for example, the tilt and distance of the mirror body may be measured. In general, the specular body has a property that diffuse reflection is difficult to occur. Therefore, the apparatus of Patent Document 2 that measures distance based on diffusely reflected light cannot perform accurate measurement.
[0006]
The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical measurement apparatus capable of measuring the inclination and distance of an object to be measured.
[0007]
[Means for Solving the Problems]
As a means for achieving the above object, the invention of claim 1 is an optical measuring apparatus for irradiating a measurement object with light and measuring the inclination and distance of the measurement object based on the reflected light. The angle measurement light projecting means used for angle measurement, the distance measurement light projecting means used for distance measurement, and the light from the angle measurement light projecting means and the distance measurement light projecting means are emitted as spot light. A collimator lens, and the angle measurement light projecting means and the distance measurement light projecting means side or the object to be measured side than the collimator lens, and the angle measurement light projecting means and the distance measurement light projecting light A branch for guiding light from the means in the direction of the object to be measured and for branching specularly reflected light from the object to be measured in a direction different from the angle measuring light projecting means and the distance measuring light projecting means side Means and said regular reflection A converging lens for converging light, and an angle for condensing specularly reflected light (angle-measuring specularly reflected light) from the angle-measuring light projecting means among the specularly reflected light converged by the converging lens on the imaging surface Of the specularly reflected light converged by the measuring imaging means and the converging lens, specularly reflected light (distance measuring specularly reflected light) from the distance measuring light projecting means is converged by the converging lens. Based on the distance measurement imaging means arranged so that light is irradiated to different positions on the imaging surface according to the distance of the detection target object, and the light collection position in the angle measurement imaging means Measurement that measures the tilt of the object to be measured and measures the distance to the object to be measured based on the light collection position in the imaging means for angle measurement and the irradiation position on the imaging surface of the imaging means for distance measurement And a stage, an optical path from said distance measuring light projecting means to said object to be measured has a characteristic where the are arranged so as to have a predetermined angle with respect to the baseline axis.
[0008]
According to a second aspect of the present invention, in the first aspect, the distance measuring imaging unit includes the distance measuring light projecting unit out of the regular reflection light converged by the converging lens in the optical axis direction. It is configured to be movable in the optical axis direction at a position where specularly reflected light (distance measuring specularly reflected light) is emitted on the imaging surface.
[0009]
The invention of claim 3 is the one described in claim 2,
Moving means for moving the imaging means for measuring the distance in the optical axis direction;
Resolution setting means for setting the resolution in the measurement;
Predetermined storage means,
For each resolution set by the resolution setting means, the storage means stores position information of the distance measurement imaging means in the optical axis direction, and correction coefficient information at the position,
The measuring means reads out the position information in the optical axis direction of the imaging means for distance measurement corresponding to the resolution set by the resolution setting means from the storage means, and the distance measurement is performed by the moving means. The image pickup means is controlled to move in the optical axis direction, the correction coefficient information is read, and the irradiation position on the image pickup surface of the distance measurement image pickup means is corrected based on the read correction coefficient information. The distance to the object to be measured is measured based on the corrected irradiation position and the condensing position in the angle measurement imaging means.
[0010]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the pulse lighting is alternately performed by driving the angle measuring light projecting unit and the distance measuring light projecting unit, respectively. And the measuring means measures the inclination of the object to be measured based on the condensing position on the imaging surface of the imaging means for angle measurement in synchronization with lighting of the light projection means for angle measurement, It is characterized in that the distance of the object to be measured is measured based on the irradiation position on the imaging surface of the distance measuring imaging means in synchronization with the lighting of the distance measuring light projecting means.
[0011]
The invention according to claim 5 is the one according to any one of claims 1 to 4, wherein the collimator lens is a first collimator lens that converts light from the angle measurement light projecting means into parallel light; And a second collimator lens that converts the light from the distance measuring light projecting means into parallel light, and includes a light combining means that combines the two parallel lights and guides them to the branching means. .
[0012]
A sixth aspect of the present invention is the configuration according to any one of the first to fifth aspects, wherein the angle measuring light projecting unit and the distance measuring light projecting unit emit light in different wavelength bands. The angle measurement regular reflection light and the distance measurement regular reflection light are reflected by one and transmitted through the other, thereby guiding the angle measurement regular reflection light to the angle measurement imaging means, It is characterized in that a dichroic mirror for splitting light that guides the regular reflection light for distance measurement to the imaging means for distance measurement is provided.
[0013]
According to a seventh aspect of the present invention, the angle measuring light projecting unit and the distance measuring light projecting unit have the same polarization direction. The polarized light is emitted, and the branching unit is constituted by a polarization beam splitter. On the other hand, the object to be measured is a specular body having a mirror-like surface, and the polarized beam. A quarter-wave plate that is disposed between the splitter and the object to be measured and transmits the light from the polarization beam splitter and transmits the angle-reflecting regular reflection light and the distance-measuring regular reflection light. It is characterized by the provision.
[0014]
The invention according to an eighth aspect is characterized in that, in any one of the first to seventh aspects, the angle measuring light projecting means and the distance measuring light projecting means comprise a laser light source.
[0015]
Operation and effect of the invention
<Invention of Claim 1>
According to the first aspect of the present invention, since the distance and the inclination are measured based on the specularly reflected light from the object to be measured, the inclination and distance can be measured regardless of the specular body or the non-specular body. Measurements can be made.
[0016]
<Invention of Claim 2>
According to the second aspect of the present invention, the resolution can be varied according to the measurement conditions, and the corresponding range can be expanded in one optical measuring device. Specifically, for example, it is possible to cope with various situations such as when it is desired to widen the measurement range even when the resolution is lowered, or when it is desired to increase the resolution by reducing the measurement range.
[0017]
<Invention of Claim 3>
According to the third aspect of the present invention, the position of the distance measuring imaging means and the correction calculation of the measuring means are automatically determined according to the resolution selected according to the user's usage environment. ) Is further improved.
[0018]
<Invention of Claim 4>
According to invention of Claim 4, the light radiate | emitted from both does not interfere, but a more accurate measurement can be performed.
[0019]
<Invention of Claim 5>
In the fifth aspect of the invention, the light from both the light projecting means is changed to parallel light by the first and second collimator lenses and then guided to the branching means. It is not necessary to adjust the target distance, and the assembly accuracy of the optical system in the apparatus can be moderated. Also, the adjustment work of the optical system can be simplified.
[0020]
<Invention of Claim 6>
According to the sixth aspect of the present invention, the angle-measuring specularly reflected light and the distance-measuring specularly reflected light can be separated by wavelength, so that more accurate measurement can be performed.
[0021]
<Invention of Claim 7>
In the invention of claim 7, the light emitted from both the light projecting means is irradiated to the mirror body through the polarizing beam splitter and the quarter wavelength plate as light having one polarization direction. The light transmitted through the quarter-wave plate is converted into circularly polarized light and irradiated onto the mirror body, and the reflected light from the mirror body passes through the quarter-wave plate while remaining circularly polarized. Then, the reflected light, which has been circularly polarized, is changed to a polarization direction orthogonal to one polarization direction and reaches the polarization beam splitter, and the light travels in a direction different from the incident direction of the light of one polarization direction.
This makes it possible to reduce optical loss and improve the S / N ratio in mirror body detection.
[0022]
<Invention of Claim 8>
Since the light emitted from the laser light source is linearly polarized light (that is, light having one polarization direction), the configuration for emitting linearly polarized light can be simplified.
[0023]
In one of claims 1 to 8,
The collimator lens may change the light from the angle measurement light projecting means and the distance measurement light projecting means into parallel light, or may change it into convergent light that gradually converges. That is, parallel light may be emitted as spot light, or convergent light may be emitted. More specifically, it may be configured to emit light that becomes a minute spot on the object to be measured.
For example, in the case of changing to parallel light, light from the focal position of regular reflection light (distance measurement regular reflection light) by the light from the distance measuring means among the regular reflection light converged by the converging lens. The distance measuring imaging means can be configured such that an imaging surface is arranged shifted in the axial direction back and forth, and the distance measuring regular reflection light is irradiated onto the imaging surface.
In addition, when the configuration of claim 2 is applied to the configuration of the distance measuring imaging unit in this way, the distance measurement of the regular reflection light converged by the converging lens in the optical axis direction. For the distance measurement so as to be movable at the position where the imaging surface is arranged by shifting back and forth in the optical axis direction from the focal position of the regular reflection light (distance measurement regular reflection light) by the light from the light projection means Imaging means can be configured.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
<First Embodiment>
A first embodiment of an optical measuring device according to the present invention will be described with reference to FIGS. The configuration of the present embodiment is as shown in FIG. 1, and the light emitted from the angle measuring laser light source 11 and the distance measuring laser light source 21 is converted into a dichroic mirror 31 (light converging means), a beam splitter 32, and a collimator lens 33 ( The workpiece W (object to be measured) is irradiated with both lights via a collimator lens and a converging lens), and the specularly reflected light is applied to a collimator lens 33, a beam splitter 32, and a dichroic mirror 34 (a dichroic mirror for splitting light). Via, for example, an imaging surface of an angle measuring image pickup element 12 (angle measuring image pickup means) composed of a two-dimensional CCD and a distance measurement image pickup element 22 (distance measurement image pickup means) also formed of a two-dimensional CCD, The inclination and distance of the workpiece W are calculated by the CPU 4 (measurement means) based on the position. The surface of the workpiece W may be a mirror surface or a non-mirror surface.
[0025]
Both laser light sources 11 and 21 emit light having different wavelengths, for example, the angle measuring laser light source 11 emits laser light having a wavelength λ1, while the distance measuring laser. The light source 21 emits laser light having a wavelength λ2. Laser drive circuits 13 and 23 are connected to the laser light sources 11 and 21, respectively, and drive currents Ia and Ib are supplied to the laser light sources 11 and 21 based on control signals Sa and Sb from the CPU 4, respectively. (An angle measuring light source 11 and a laser driving circuit 13 constitute an angle measuring light projecting means, and a distance measuring laser light source and a laser driving circuit 13 constitute a distance measuring light projecting means). The laser light sources 11 and 21 can be driven intermittently or continuously.
[0026]
The dichroic mirror 31 is configured to transmit the light with the wavelength λ1 and reflect the light with the wavelength λ2, so that the laser light of the angle measuring laser light source 11 is transmitted through the dichroic mirror 31 and the beam splitter. The light from the distance measuring laser light source 21 is reflected by the dichroic mirror 31 and travels toward the beam splitter 32.
The laser light from the angle measuring laser light source 11 is incident on the incident surface of the dichroic mirror 31 perpendicularly, and the laser light from the distance measuring laser light source 21 is incident obliquely on the incident surface of the dichroic mirror 31. (Corresponding to a configuration in which the distance measuring light projecting unit is arranged so that light from the distance measuring light projecting unit is obliquely applied to the object to be measured). As a result, the light axis of the angle measuring laser light source 11 is made parallel to the optical axis (base line axis) LC (L′ C ′) of the optical system, and the light axis of the distance measuring laser light source 21 is the light of the optical system. The state is inclined with respect to the axis LC (L′ C ′).
[0027]
The laser light reflected from the beam splitter 32 is converted into parallel light by the collimator lens 33 and irradiated onto the workpiece W. At this time, the laser light from the angle measurement laser light source 11 is irradiated perpendicularly to the surface of the workpiece W when the workpiece W is in a posture without inclination, whereas the laser beam for distance measurement is used. Since the laser light from the laser light source 21 is inclined with respect to the optical axis LC (L′ C ′) of the optical system, the light is irradiated obliquely onto the surface of the workpiece W. The spot diameter of the laser light applied to the workpiece W is smaller for the laser light 21 of the laser light source 21 than for the laser light of the laser light source 11, and the laser light of the laser light source 21 is a laser light source. 11 is irradiated within the irradiation range of the laser beam.
[0028]
The specularly reflected light from the workpiece W is collected by the collimator lens 33, and is specularly reflected by the angle measuring laser light source 11 (the specularly reflected light for angle measurement) by the dichroic mirror 34 having the same characteristics as the dichroic mirror 31. ) Forms an image on the imaging surface of the angle-measuring imaging device 12 to form a focused spot. Further, the regular reflection light (distance measurement regular reflection light) from the distance measurement laser light source 21 is reflected by the dichroic mirror 34 and applied to the imaging surface of the distance measurement image sensor 22. Since the image pickup surface of the distance measuring image pickup element 22 is arranged behind the focal position F of the regular reflection light, a light image having a predetermined size is formed on the image pickup surface. Here, the reason why the imaging surface of the distance measuring image pickup element 22 is not coincident with the focal position F is that the optical path to the focal position F changes according to the distance of the workpiece W. This is because the distance of the workpiece W can be calculated.
[0029]
The angle measuring image pickup device 12 and the distance measuring image pickup device 22 transmit to the CPU 4 image pickup signals Sc and Sd formed of a digital signal sequence corresponding to a light image or a condensing spot formed on the image pickup surface.
[0030]
The CPU 4 transmits the control signals Sa and Sb to the laser drive circuits 13 and 23 described above, captures the imaging signal Sc from the angle measurement imaging device 12 in synchronization with the transmission of the control signal Sa, and transmits the control signal Sb. The image pickup signal Sd from the distance measuring image pickup device 22 is captured in synchronization with the above. Then, the inclination of the workpiece W and the distance from the collimator lens 33 to the workpiece W are measured based on the imaging signals Sc and Sd.
[0031]
The configuration of the present embodiment is as described above, and the operation will be described next.
"Tilt detection"
In the present embodiment, the tilt measurement is performed using a well-known autocollimation method, and detailed description thereof is omitted here. First, from the imaging signal Sc from the angle measurement imaging device 12, the pixel having the maximum amount of received light is determined as the condensing spot position, and the reference position on the imaging surface (for example, the center position of the imaging surface) and the condensing spot position are determined. The inclination direction and the inclination angle are calculated from the distance and direction.
[0032]
"Distance measurement"
In the distance measurement, first, the angle of the workpiece W is detected by the above inclination measurement. Then, based on the imaging signal Sd from the distance measuring imaging element 22, for example, a pixel having the maximum received light amount is represented as an optical image. Then, correction is performed based on the inclination calculated by the inclination measurement, and the distance of the workpiece W is calculated from the distance and direction between the position of the optical image and the reference position.
[0033]
For example, when the work W is at the position (1) (distance d1, inclination angle 0) in FIG. 1 (refer to FIG. 2 for details), the light condensing formed on the imaging surface of the angle measuring image sensor 12. Since the spot position S1 coincides with the reference position Ra, the inclination angle is measured as 0 °. Further, since the optical image L1 on the imaging surface of the distance measurement imaging element 22 is d1 ′ away from the reference position Rb, the distance d1 is measured based on this.
When the workpiece W is at the position (2) (distance d2, inclination angle 0) in FIG. 1 (refer to FIG. 3 for details), the condensing spot formed on the imaging surface of the angle measuring image sensor 22 Since the position S2 coincides with the reference position Ra, the inclination angle is measured as 0 °. Further, since the optical image L2 on the imaging surface of the distance measuring imaging element 12 is separated from the reference position Rb by d2 ′, this is measured as the distance d2.
When the workpiece W is at the position (3) (distance d2, inclination angle θ1) in FIG. 1 (refer to FIG. 4 for details), the position of the light receiving spot formed on the imaging surface of the angle measurement imaging device 12 Since S3 is separated from the reference position Ra by the distance d, the inclination angle θ1 is measured based on this distance. Further, the optical image L3 on the imaging surface of the distance measuring imaging element 22 is separated from the reference position Rb by d3 ′. Here, since the workpiece W is inclined at the position {circle around (3)}, the optical image L3 formed on the imaging surface of the distance measuring image pickup device 22 is formed at a position different from the optical image L2 at the position {circle around (2)}. Is done. Therefore, since the CPU 4 calculates the distance by performing correction based on the inclination angle θ1, the distance is eventually measured as d2.
[0034]
According to the present embodiment, since the distance and the inclination are measured based on the regular reflection light from the work W, the inclination and the distance of the work W are measured regardless of the specular body or the non-specular body. It can be performed. Further, the laser light sources 11 and 21 are configured to emit light of different wavelengths, and the laser light is separated by the dichroic mirrors 31 and 34 so that the imaging surfaces of the imaging elements 12 and 22 are irradiated. Since it is configured, laser light is not erroneously irradiated.
In the present embodiment, the spot diameter of the laser light applied to the workpiece W is smaller than the laser light of the laser light source 21 than the laser light of the laser light source 11 and the laser of the laser light source 21 is used. Since the light is irradiated within the laser light irradiation range of the laser light source 11, the irradiation position (measurement position) of the laser light on the workpiece W is substantially constant regardless of the distance and inclination of the workpiece W. can do.
[0035]
Moreover, in the said structure, it can also be set as the structure which radiate | emits the laser beam of the same wavelength from both the laser light sources 11 and 21. FIG. In this case, the control signals Sa and Sb are supplied from the CPU 4 to the laser drive circuits 13 and 23 so that the respective laser light sources 11 and 21 are alternately lit, and a beam splitter, for example, is arranged in place of the dichroic mirrors 31 and 34. You just have to do it. Further, as described above, the CPU 4 transmits the control signals Sa and Sb to the laser drive circuits 13 and 23, and captures the image pickup signal Sc from the angle measurement image pickup device 12 in synchronization with the transmission of the control signal Sa. In synchronization with the transmission of Sb, the imaging signal Sd from the distance measuring imaging element 22 is captured. The tilt of the workpiece W and the distance from the collimator lens 33 to the workpiece W are measured based on the imaging signals Sc and Sd. If it does in this way, for example, a laser beam will be radiate | emitted alternately, interference of light will be suppressed and the effect that a measurement precision improves will be acquired.
[0036]
Furthermore, as shown in FIG. 5, a configuration may be adopted in which a diverging lens 35 is disposed in front of the distance measurement imaging element 22 so that specularly reflected light from the work W once condensed is diverged. In this way, since the optical image formed on the imaging surface is made larger, the amount of movement of the optical image when the workpiece W is displaced is increased, resulting in improved resolution and high-precision measurement. be able to. Further, it is more desirable to irradiate the peripheral portion of the diverging lens 35 with the regular reflection light. This is because the aberration is larger in the peripheral portion than in the central portion of the lens 35, and the specularly reflected light is further diverged, so that it can be measured with extremely high accuracy.
[0037]
Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG. The difference between the present embodiment and the first embodiment is that a collimator lens 14 (first collimator lens) is disposed between the angle measurement laser light source 11 and the dichroic mirror 31, and the distance measurement laser light source 21. And a dichroic mirror 31 are arranged with a collimator lens 24 (second collimator lens) so that the light from the respective laser light sources 11 and 21 is converted into parallel light and then reaches the dichroic mirror 31. Has been. A converging lens 36 is disposed between the dichroic mirror 34 and the beam splitter 33.
[0038]
With this configuration, the laser light from both laser light sources 11 and 21 is converted into parallel light by the respective collimator lenses 14 and 24 and then guided to the beam splitter 33. It is not necessary to adjust the optical distance to the beam splitter 33, and the assembly accuracy of the optical system in the apparatus can be moderated, and the adjustment work of the optical system can be simplified.
[0039]
<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIG. The difference between the present embodiment and the second embodiment is that a polarization beam splitter 37 that reflects S-polarized light and transmits P-polarized light is disposed in place of the beam splitter 33, and further, the polarization beam splitter 37 and the workpiece W are different from each other. A quarter-wave plate 38 is provided between them. The surface of the workpiece W is preferably a mirror surface.
[0040]
In general, the laser light is linearly polarized. Therefore, when the laser beams from both laser light sources 11 and 21 are irradiated onto the polarization beam splitter 37, the S-polarized light is reflected and travels toward the quarter-wave plate 37, and the P-polarized light is To Penetrate. The S-polarized light is changed to circularly-polarized light by passing through the quarter-wave plate 38 and is irradiated onto the workpiece W. The regular reflection light from the work W is transmitted through the quarter-wave plate 38 as circularly polarized light. At this time, the circularly polarized light is changed to P-polarized light, and the light is transmitted through the polarization beam splitter 37 and irradiated to the respective image sensor means 12 and 22.
[0041]
By adopting the configuration of this embodiment, it is possible to reduce optical loss and improve the S / N ratio in mirror body detection. In addition, since the light emitted from the laser light sources 11 and 21 is linearly polarized light, the configuration for emitting linearly polarized light can be greatly simplified.
[0042]
<Fourth embodiment>
A fourth embodiment of the optical measuring apparatus according to the present invention will be described with reference to FIG. The present embodiment is as shown in the schematic diagram of FIG. 8 and the component configuration diagram of FIG. 9, and is configured to detect inclination and distance using the same principle as the above embodiment. It is first described that the feature of the present embodiment is that the resolution can be changed by moving the position of the distance measuring image sensor.
[0043]
As shown in FIGS. 8 and 9, the light emitted from the angle measuring laser light source 11 and the distance measuring laser light source 21 is irradiated to the workpiece W (object to be measured) through the polarization beam splitter 37. Then, the specularly reflected light is transmitted from the angle measuring image pickup device 12 (angle measuring image pickup means), which is a two-dimensional CCD, for example, through the converging lens 36 and the dichroic mirror 34 (light branching dichroic mirror) and the two-dimensional CCD. The distance measurement imaging element 22 (distance measurement imaging means) is irradiated to the imaging surface, and the inclination and distance of the workpiece W are calculated by the CPU 4 (measurement means) based on the irradiation position. The surface of the workpiece W may be a mirror surface or a non-mirror surface.
[0044]
Both laser light sources 11 and 21 emit light having different wavelengths, for example, the angle measuring laser light source 11 emits laser light having a wavelength λ1, while the distance measuring laser. The light source 21 emits laser light having a wavelength λ2. Laser drive circuits 13 and 23 are connected to the laser light sources 11 and 21, respectively, and drive currents Ia and Ib are supplied to the laser light sources 11 and 21 based on control signals Sa and Sb from the CPU 4, respectively. (An angle measuring light source 11 and a laser driving circuit 13 constitute an angle measuring light projecting means, and a distance measuring laser light source and a laser driving circuit 13 constitute a distance measuring light projecting means). The laser light sources 11 and 21 can be driven intermittently or continuously.
[0045]
The reflection mirror 44 is configured to reflect the light of the wavelength λ1 from the angle measurement laser light source 11, whereby the laser light of the angle measurement laser light source 11 passes through the reflection mirror 44 and is a polarization beam splitter. Head to 37. The distance measuring laser light source 21 is arranged on the same side as the distance measuring image pickup element 22 arranged at a position folded by the dichroic mirror 34. That is, when the optical axis of the specularly reflected light for angle measurement from the workpiece W when the inclination is 0 degree is divided into right and left, it is arranged on the same side as the distance measuring image sensor 22. . Specifically, as shown in the component arrangement of FIG. 9, the distance measuring laser light source 21 is disposed using a dead space generated on the lower side of the distance measuring image sensor 22, so that the apparatus of the autocollimator The whole is housed compactly.
[0046]
Here, the distance measuring laser light source 21 is linearly polarized laser light. For example, the parallel light emitted from the distance measuring laser light source 21 through the collimator lens 24 is P-polarized laser light, and the polarizing beam splitter. In 37, the P-polarized light is transmitted, passes through the ¼λ plate 43, is reflected by the reflection mirror 42, and passes through the ¼λ plate 43 again to be polarized from P-polarized light to S-polarized light. The S-polarized light that enters the splitter 37 is reflected by the beam splitter 37 and applied to the workpiece W.
[0047]
The laser light from the angle measuring laser light source 11 is incident perpendicularly to the incident surface of the reflecting mirror 44, and the laser light from the distance measuring laser light source 21 is incident obliquely with respect to the incident surface of the reflecting mirror 44. (Corresponding to a configuration in which the distance measuring light projecting unit is arranged so that light from the distance measuring light projecting unit is obliquely applied to the object to be measured). As a result, the light axis of the angle measuring laser light source 11 is made parallel to the optical axis (base line axis) LC (L′ C ′) of the optical system, and the light axis of the distance measuring laser light source 21 is the light of the optical system. The state is inclined with respect to the axis LC (L′ C ′).
[0048]
The laser beam reflected from the beam splitter 37 is irradiated onto the workpiece W. At this time, the laser light from the angle measurement laser light source 11 is irradiated perpendicularly to the surface of the workpiece W when the workpiece W is in a posture without inclination, whereas the laser beam for distance measurement is used. Since the laser light from the laser light source 21 is inclined with respect to the optical axis LC (L′ C ′) of the optical system, the light is irradiated obliquely onto the surface of the workpiece W. The spot diameter of the laser light applied to the workpiece W is smaller for the laser light 21 of the laser light source 21 than for the laser light of the laser light source 11, and the laser light of the laser light source 21 is a laser light source. 11 is irradiated within the irradiation range of the laser beam.
[0049]
The specularly reflected light from the workpiece W is collected by the dichroic mirror 34, and the specularly reflected light (angled specularly reflected light) from the angle measuring laser light source 11 forms an image on the imaging surface of the angle measuring image pickup device 12 and is condensed. A spot is formed. Further, the regular reflection light (distance measurement regular reflection light) from the distance measurement laser light source 21 is reflected by the dichroic mirror 34 and applied to the imaging surface of the distance measurement image sensor 22. Since the image pickup surface of the distance measuring image pickup element 22 is arranged behind the focal position F of the regular reflection light, a light image having a predetermined size is formed on the image pickup surface. Here, the reason why the imaging surface of the distance measuring image sensor 22 is not matched with the focal position F 1 is that the optical path to the focal position F changes according to the distance of the work W as in the above embodiment. This is because the distance of the workpiece W can be calculated from the position of the optical image. The angle measuring image pickup device 12 and the distance measuring image pickup device 22 transmit to the CPU 4 image pickup signals Sc and Sd formed of a digital signal sequence corresponding to a light image or a condensed spot formed on the image pickup surface. It has become.
[0050]
The CPU 4 transmits the control signals Sa and Sb to the laser drive circuits 13 and 23 described above, captures the imaging signal Sc from the angle measurement imaging device 12 in synchronization with the transmission of the control signal Sa, and transmits the control signal Sb. The image pickup signal Sd from the distance measuring image pickup device 22 is captured in synchronization with the above. Then, the inclination of the workpiece W and the distance to the workpiece W are measured based on the imaging signals Sc and Sd.
[0051]
In the present embodiment, the distance measurement imaging means (that is, the distance measurement imaging device 22) is moved in the optical axis direction, and the resolution setting means (CPU 4 corresponds to the resolution setting means) for setting the resolution in the measurement. ) And a predetermined storage means (the memory 41 corresponds to the storage means). In the memory 41, as shown in FIG. 13, for each resolution set by the resolution setting means, position information of the distance measurement imaging means in the optical axis direction and correction coefficient information at the position are stored. The position information in the optical axis direction of the distance measuring imaging means corresponding to the resolution set by the resolution setting means is read from the storage means, and the distance measuring imaging means is moved in the optical axis direction by the moving means. In addition to performing control, the correction coefficient information is read out, the irradiation position on the imaging surface of the distance measurement imaging unit is corrected based on the read correction coefficient information, and the corrected irradiation position and the angle measurement imaging unit are collected. The distance to the object to be measured is measured based on the light position.
[0052]
"Distance measurement"
In the distance measurement, the angle of the workpiece W is first detected by measuring the inclination. Then, based on the imaging signal Sd from the distance measuring imaging element 22, for example, a pixel having the maximum received light amount is represented as an optical image. Then, correction is performed based on the inclination calculated by the inclination measurement, and the distance of the workpiece W is calculated from the distance and direction between the position of the optical image and the reference position. In the present embodiment, the distance measuring image pickup element 22 is configured to be movable with respect to the optical axis direction (baseline axis direction) by using the configuration shown in FIGS. The measurement range and resolution in the distance measurement can be changed.
[0053]
At this time, if the distance measuring image pickup element 22 is moved in the optical axis direction, the distance measuring laser light source 21 is a workpiece W having the same inclination and the same distance because of the inclination with respect to the baseline axis. In addition, the position of the spot of specularly reflected light for distance measurement from the workpiece W irradiated on the distance measurement image sensor 22 changes. Therefore, in the present embodiment, a correction coefficient corresponding to the position in the optical axis direction of the distance measuring image sensor 22 set in advance in a storage unit (memory 41) (not shown) is stored, and the distance measuring image sensor in the optical axis direction is stored. According to the position of 22, the correction is made based on the correction coefficient stored in the distance measurement.
[0054]
Specifically, for example, as shown in the data configuration of FIG. 13, the position data and the correction coefficient data are stored in the memory 41 in association with each other, and correction coefficient data corresponding to the position of the distance measuring image sensor 22 is stored from the memory 41. Reading is performed to correct the imaging signal Sd (specifically, the focused spot position is corrected). In this configuration, when the user sets the resolution, the distance measuring imaging element 22 is moved by the moving means 40 using the position data corresponding to the resolution, and the correction coefficient data is used for the imaging signal Sd at that position. The distance is calculated by correcting the focused spot position. The configuration in which the resolution can be changed so that the position of the image sensor for distance measurement can be moved is not limited to the configuration as shown in FIG. 8, but can be applied to any of the above embodiments.
[0055]
Next, the moving means 40 will be described.
The moving means 40 shown in FIG. 10 is intended to move the distance measuring image sensor 22 using a gear transmission mechanism, and linearly moves the distance measuring image sensor 22 using a rack 52 and a pinion 51. The configuration is conceptually illustrated. The position of the pinion 51 is accurately controlled by a motor (not shown) using position data. The motor control using the position data is well known and will not be described in detail. Note that, as in the example of FIG. 10B, a scale 53 may be provided in a part of the distance measuring image pickup device 22 and detected by the photoelectric sensor 55 to set the position accurately. . FIG. 11 shows a configuration in which position control is performed using a worm 63 and a wheel 61. FIG. 12 shows that the distance measuring image sensor 22 is configured to be reciprocally movable, while the engaging portion 71 biased by the spring 73 is engaged with a recess provided in the distance measuring image sensor 22. Is a stepwise positioning configuration. 11 and 12 illustrate a configuration in which the position can be set by manual operation using the operation units 65 and 77 instead of automatic control. Of course, the configuration shown here is merely an example, and it goes without saying that various configurations can be used as long as the configuration can move the image sensor 22 for distance measurement.
[0056]
<Fifth Embodiment>
In the above embodiment, the pixel having the maximum amount of received light is determined as the condensing spot position from the imaging signal Sd from the distance measuring image sensor 22 and the imaging signal Sc from the angle measuring image sensor 12, respectively. In this embodiment, in order to calculate each condensing spot, the gravity center position of irradiation light can be calculated | required. The concept of the centroid position includes so-called area centroid position and volume centroid position, which are defined as follows.
[0057]
<Area of center of gravity>
Area centroid position = {Σ (MI) / ΣM}
I: Position vector of each pixel in the irradiation area on the imaging surface of the imaging means
M: For example, 1 when the received light amount level of each pixel is equal to or higher than a predetermined level, and 0 otherwise.
[0058]
<Volume center of gravity position>
Volume centroid position = {Σ (mI) / Σm}
I: Same as in the case of the area centroid position
m: coefficient corresponding to the received light level of each pixel
[0059]
By using the position of the center of gravity defined in this way as a condensing spot, distance measurement with higher accuracy becomes possible. In addition, when the method of determining the position of the center of gravity by using the focused spot as described above is used, the processing time can be greatly shortened as compared with the method of performing the averaging process many times to determine the focused spot. Note that the method of determining the position of the center of gravity as the focused spot in this way can be applied to any of the above embodiments.
[0060]
<Sixth Embodiment>
In the above embodiment, the collimator lens 24 changes the light from the distance measuring light projecting means into parallel light. However, in the present embodiment, the “spot light” emitted from the collimator lens 24 is emitted from the collimator lens 24. It is configured to emit convergent light that converges gradually. Here, the same components as those shown in FIG. 8 are used and the arrangement is almost the same, but imaging is performed at the point of the condensing position F, where convergent light that converges gradually from the collimator lens 24 is emitted. The main difference is that the surfaces are arranged. In this configuration, the convergent light that gradually converges from the collimator lens 24 is collected in the vicinity of the workpiece W and is expanded again by reflection from the workpiece W. Then, the light converged through the converging lens 36 and reflected by the dichroic mirror 34 is irradiated onto the imaging surface provided at the condensing position F. The irradiation position on the imaging surface is a position corresponding to the distance of the workpiece W as in the above embodiment. Further, the position may be set by the moving means 40 so that the imaging surface is not disposed at the condensing position F but is disposed at another position.
[0061]
In the configuration of FIG. 14, the regular reflection light (distance measurement regular reflection light) by the light from the distance measurement light projecting means is converged by the converging lens 36, reflected by the dichroic mirror 34, and condensed. However, the configuration may be such that the reflected light gradually spreading from the workpiece W is converted into parallel light by the converging lens 36. In this case, the distance measurement imaging device 22 is configured to be irradiated with parallel light, and the irradiation region of the parallel light changes according to the distance of the workpiece W. In this parallel light irradiation region, the focused spot may be obtained by the various methods described above, and the distance may be measured.
[0062]
<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the first embodiment, the configuration in which the distance measuring imaging element 22 is arranged behind the focal position F of the regular reflection light by the distance measuring laser light source 21 is shown. It is good also as a structure arrange | positioned. Accordingly, of course, the diverging lens 35 is arranged in front of the focal position F and the distance measuring image pickup element 22.
(2) In the first embodiment, the configuration in which the diverging lens 35 is disposed in front of the distance measuring image pickup device 22 can be added to the configurations of the second and third embodiments.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the overall configuration of an optical measurement apparatus according to a first embodiment.
FIG. 2 is a schematic diagram showing the position of a workpiece and the optical path of reflected light.
FIG. 3 is a schematic diagram showing the position of a workpiece and the optical path of reflected light.
FIG. 4 is a schematic diagram showing the position of a workpiece and the optical path of reflected light.
FIG. 5 is a schematic diagram showing a modification of the first embodiment.
FIG. 6 is a schematic diagram showing an overall configuration of an optical measuring device according to a second embodiment.
FIG. 7 is a schematic diagram showing the overall configuration of an optical measurement apparatus according to a third embodiment.
FIG. 8 is a schematic diagram showing an overall configuration of an optical measuring device according to a fourth embodiment.
FIG. 9 is a diagram illustrating a component arrangement configuration of a main part of an optical measurement device according to a fourth embodiment.
FIG. 10 is a schematic view schematically illustrating a moving means.
11 is a schematic view illustrating a moving means different from FIG.
12 is a schematic view illustrating a moving means different from FIG.
FIG. 13 is an explanatory diagram conceptually illustrating a data configuration stored in a storage unit.
FIG. 14 is a schematic diagram showing the overall configuration of an optical measuring device according to a sixth embodiment.
[Explanation of symbols]
4 ... CPU
11 ... Laser light source for angle measurement
12. Image sensor for angle measurement
13 ... Laser drive circuit
21 ... Laser light source for distance measurement
22 ... Image sensor for distance measurement
23 ... Laser drive circuit
31 ... Dichroic mirror
32 ... Beam splitter
33 ... Collimator lens
40. Moving means
41 ... Memory
W ... Work
LC: Optical axis of optical system

Claims (8)

An optical measuring device that irradiates light to an object to be measured and measures the inclination and distance of the object to be measured based on the reflected light,
A light projection means for angle measurement used for angle measurement;
A distance measuring projection means used for distance measurement;
A collimator lens that emits light from the angle measuring light projecting unit and the distance measuring light projecting unit as spot light; and
Light from the angle measuring light projecting means and the distance measuring light projecting means, or from the angle measuring light projecting means and the distance measuring light projecting means, than the collimator lens. And branching means for branching specularly reflected light from the measurement object in a direction different from the angle measurement light projecting means and the distance measurement light projecting means side,
A converging lens for converging the specularly reflected light;
Angle measuring imaging means for condensing specularly reflected light (angle measuring specularly reflected light) by the light from the angle measuring light projecting means among the specularly reflected light converged by the converging lens;
Of the specularly reflected light converged by the converging lens, the specularly reflected light (distance measuring specularly reflected light) from the distance measuring light projecting means is converged by the converging lens. Distance measuring imaging means arranged to irradiate different positions on the imaging surface according to the distance of the object;
The inclination of the measurement object is measured based on the condensing position in the angle measuring imaging means, and based on the condensing position in the angle measuring imaging means and the irradiation position on the imaging surface of the distance measuring imaging means. Measuring means for measuring the distance to the object to be measured,
An optical measurement apparatus, wherein an optical path from the distance measuring light projecting means to the object to be measured is arranged so as to have a predetermined angle with respect to a base line axis. The distance measuring imaging means includes:
Of the regular reflection light converged by the converging lens in the optical axis direction, regular reflection light (distance measurement regular reflection light) by the light from the distance measurement light projecting means is irradiated onto the imaging surface. The optical measurement apparatus according to claim 1, wherein the optical measurement apparatus is configured to be movable in the optical axis direction at a certain position. Moving means for moving the distance measuring imaging means in the optical axis direction;
Resolution setting means for setting the resolution in the measurement;
Predetermined storage means,
For each resolution set by the resolution setting means, the storage means stores position information of the distance measurement imaging means in the optical axis direction, and correction coefficient information at the position,
The measuring means reads out the position information in the optical axis direction of the imaging means for distance measurement corresponding to the resolution set by the resolution setting means from the storage means, and the distance measurement is performed by the moving means. The image pickup means is controlled to move in the optical axis direction, the correction coefficient information is read, and the irradiation position on the image pickup surface of the distance measurement image pickup means is corrected based on the read correction coefficient information. 3. The optical measurement apparatus according to claim 2, wherein a distance to the object to be measured is measured based on the corrected irradiation position and the light collection position in the angle measurement imaging means. As the angle measuring light projecting means and the distance measuring light projecting means are pulse-driven by alternately driving pulses,
The measuring means measures the inclination of the object to be measured based on the condensing position on the imaging surface of the angle measuring imaging means in synchronization with the lighting of the angle measuring light projecting means, and on the other hand, the distance 4. The distance of the object to be measured is measured based on the irradiation position on the imaging surface of the imaging means for distance measurement in synchronization with lighting of the light projecting means for measurement. The optical measuring device according to any one of the above. The collimator lens is
A first collimator lens that converts the light from the angle measuring light projecting means into parallel light;
A second collimator lens that converts the light from the distance measuring light projecting means into parallel light;
The optical measuring device according to claim 1, further comprising an optical converging unit that combines the parallel lights and guides the parallel light to the branching unit. The angle measuring light projecting means and the distance measuring light projecting means are configured to emit light in different wavelength bands,
Reflecting one of the regular reflection light for angle measurement and the regular reflection light for distance measurement and transmitting the other, guides the regular reflection light for angle measurement to the imaging means for angle measurement and transmits the regular reflection light for distance measurement. 6. The optical measurement apparatus according to claim 1, further comprising a light branching dichroic mirror that guides reflected light to the distance measurement imaging means. The angle measuring light projecting unit and the distance measuring light projecting unit are configured to emit polarized light having the same polarization direction, and the branching unit includes a polarization beam splitter. And
On the other hand, the measurement object is a mirror body having a mirror-like surface,
¼ disposed between the polarization beam splitter and the measurement object, and transmits the light from the polarization beam splitter and transmits the angle measurement regular reflection light and the distance measurement regular reflection light. The optical measuring device according to claim 1, further comprising a wave plate. The optical measurement apparatus according to claim 1, wherein the angle measurement light projecting unit and the distance measurement light projecting unit are laser light sources.

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