JP7247075B2 - Laser light collecting device, laser light receiving device, and laser light collecting method - Google Patents

Description

TECHNICAL FIELD Embodiments of the present invention relate to a laser light collecting device, a laser light receiving device, and a laser light collecting method.

As light with excellent directivity and convergence and coherence, lasers are used in a wide range of technical fields such as material processing, spectroscopy, and measurement.The range of applications includes laser surgery, holographic imaging, etc. Diverse. Laser vibrometers and laser rangefinders are commonly used as devices capable of optically measuring and quantifying the vibration of an object and the distance to the object using laser light. These devices and methods irradiate an object with a laser and measure the light reflected by the surface of the object using an interferometer or a light detection sensor.

Techniques for analyzing the elemental composition of an object by emission spectroscopy, such as laser-induced breakdown spectroscopy, are also widely used. Methods such as laser ultrasonic testing (LUT), which excites ultrasonic waves by irradiating an object with a pulsed laser and measures minute vibrations on the surface of the object using a separate laser and a laser interferometer, have also been put to practical use. .

Since the laser ultrasonic method can be inspected without contact, it is applied to inspections during welding work, etc. Various forms have been proposed for apparatuses and methods for converting into a sintered body, depending on the intended use. In addition, methods such as measuring the shape of the molten pool during welding using the laser ultrasonic method have been devised, and ultrasonic waves are used to detect the interface between the molten pool, which is a liquid, and the base metal, which is a solid. Thus, a method for evaluating the metal melting process in real time is presented.

Japanese Patent No. 5651533 Japanese Patent No. 6559604

When irradiating an object with a laser to obtain information such as the physical properties, vibration, and distance to the object, the amount of laser light that can be received depends on the laser output, wavelength, irradiation angle, and the reflectance of the object surface to the laser. etc. For example, when irradiating a laser beam onto the surface of an object and performing measurement using the laser beam reflected from the surface, if the surface irradiated with the laser beam is curved or has a large surface roughness, the reflected light will be scattered. the amount of light received decreases. On the other hand, when the surface roughness is small, the scattering of reflected light is small, but the amount of light varies greatly depending on the light receiving position, so it is necessary to precisely adjust the installation position and angle of the light receiving mechanism. If the amount of received light is insufficient, the detection sensitivity is lowered, and if the amount of received light varies greatly, the measurement accuracy is lowered.

Accordingly, an object of the embodiments of the present invention is to efficiently collect laser light.

In order to achieve the above-mentioned object, the laser light collecting device according to the present embodiment is arranged so that the optical axis is perpendicular to the surface of the light receiving mechanism so that the light receiving mechanism senses the laser light from the light source. A laser beam condensing device for condensing the laser beam, comprising: a concave mirror having a central opening of the concave mirror formed in the center; and a convex mirror having a convex mirror central opening formed in the center thereof, the convex mirror being disposed on the optical axis of the concave mirror so that its own optical axis overlaps with the optical axis of the concave mirror; The position of the mirror on the optical axis is closer to the concave mirror side than the focal position of the concave mirror, and the diameter of the concave mirror is larger than the diameter of the convex mirror.

Further, a laser light receiving device according to the present embodiment is characterized by comprising the above-described laser light collecting device and an interferometer for interferometrically measuring the laser light.

1 is a vertical cross-sectional view showing the configuration of a laser beam condensing device according to a first embodiment; FIG. FIG. 5 is a vertical cross-sectional view showing the configuration of a modified example of the laser beam condensing device according to the first embodiment; FIG. 3 is a flow diagram showing the procedure of a laser beam condensing method according to the first embodiment; FIG. 2 is a conceptual first vertical cross-sectional view showing a conventional condensing method for explaining the effect of the laser beam condensing device according to the first embodiment; FIG. 5 is a conceptual second vertical cross-sectional view showing a conventional focusing method for explaining the effect of the laser beam focusing device according to the first embodiment; FIG. 5 is a conceptual third vertical cross-sectional view showing a conventional focusing method for explaining the effect of the laser beam focusing device according to the first embodiment; FIG. 3 is a conceptual first longitudinal sectional view showing a light receiving state of the laser light receiving device for explaining the effect of the laser light collecting device according to the first embodiment; FIG. 6 is a conceptual second vertical cross-sectional view showing the light receiving state of the laser light receiving device for explaining the effect of the laser light collecting device according to the first embodiment; FIG. 8 is a conceptual third longitudinal sectional view showing the light receiving state of the laser light receiving device for explaining the effect of the laser light collecting device according to the first embodiment; FIG. 6 is a vertical cross-sectional view showing the configuration of a laser beam condensing device according to a second embodiment; FIG. 10 is a vertical cross-sectional view showing the operation of the laser beam condensing device according to the second embodiment; FIG. 11 is a vertical cross-sectional view showing the configuration of a laser beam condensing device according to a third embodiment; It is a longitudinal cross-sectional view showing the configuration of a laser light receiving device according to a fourth embodiment. FIG. 11 is a vertical cross-sectional view showing the configuration of a modification of the laser light receiving device according to the fourth embodiment; FIG. 12 is a longitudinal sectional view showing the configuration of another modified example of the laser light receiving device according to the fourth embodiment; FIG. 11 is a conceptual vertical cross-sectional view of a conventional example for comparison to explain the first action of the laser light receiving device according to the fourth embodiment; FIG. 11 is a vertical cross-sectional view for explaining a first action of the laser light receiving device according to the fourth embodiment; FIG. 11 is a conceptual vertical cross-sectional view of a conventional example for comparison to explain the second action of the laser light receiving device according to the fourth embodiment; FIG. 11 is a conceptual vertical cross-sectional view for explaining a second action of the laser light receiving device according to the fourth embodiment; FIG. 11 is a flow diagram showing the procedure of a laser beam condensing method according to the fourth embodiment; FIG. 11 is a conceptual vertical cross-sectional view showing a laser light receiving device according to a fifth embodiment; FIG. 11 is a conceptual vertical cross-sectional view showing a laser light receiving device according to a sixth embodiment; FIG. 11 is a vertical cross-sectional view showing the configuration of a laser light receiving device according to a seventh embodiment; FIG. 11 is a vertical cross-sectional view showing the configuration of a laser light receiving device in a modified example of the seventh embodiment; FIG. 11 is a flow diagram showing the procedure of a laser beam condensing method according to the seventh embodiment;

DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser light collecting device, a laser light collecting method, and a laser light receiving device according to embodiments of the present invention will be described below with reference to the drawings. Here, portions that are the same or similar to each other are denoted by common reference numerals, and overlapping explanations are omitted.

[First Embodiment]
FIG. 1 is a vertical cross-sectional view showing the configuration of a laser beam condensing device according to the first embodiment.

The laser beam focusing device 100 has a concave mirror 110 , a convex mirror 120 and a convex lens 130 . The laser beam focusing device 100 further has a holding structure for holding the relative positions of the concave mirror 110, the convex mirror 120, and the convex lens 130 as described below, but the illustration is omitted. are doing. The same applies hereinafter.

The concave mirror 110 has a concave mirror main body 111 and a concave mirror mirror surface portion 112 arranged on the concave side thereof. The shape of the concave mirror main body 111 is, for example, a shape forming a part of an aspherical shape such as a spheroidal shape. A circular concave mirror center opening 113 is formed in the center of the concave mirror main body 111 .

The concave mirror surface portion 112 may be a mirror surface portion formed by mirror finishing or the like on the concave surface side of the concave mirror main body 111 . Alternatively, as long as it has a reflecting function, it may be a member attached to the concave side of the concave mirror main body 111 whose surface reflects.

The convex mirror 120 has a convex mirror main body 121 and a convex mirror mirror surface portion 122 arranged on the convex side thereof. The shape of the convex mirror main body 121 is, for example, a shape forming a part of an aspherical shape such as a spheroidal shape. A circular convex mirror central opening 123 is formed in the center of the convex mirror main body 121 .

The convex mirror surface portion 122 may be a mirror surface portion formed on the convex surface side of the convex mirror main body 121 by mirror finishing or the like. Alternatively, as long as it has a reflecting function, it may be a member attached to the convex side of the convex mirror main body 121 whose surface reflects.

The convex mirror surface portion 122 faces the convex portion of the concave mirror 110 in the same direction as the concave mirror 110, and is on the central axis of the concave mirror 110 (hereinafter referred to as the optical axis 101). The optical axes 101 are arranged so as to overlap. The position of convex mirror 120 on optical axis 101 is closer to concave mirror 110 than the focal position of concave mirror 110 . The diameter of concave mirror 110 is larger than the diameter of convex mirror 120 . The diameter of concave mirror central aperture 113 is smaller than the diameter of convex mirror central aperture 123 .

The convex lens 130 is arranged on the opposite side of the convex mirror 120 with the concave mirror 110 interposed therebetween so that the central axis thereof coincides with the optical axis 101 .

FIG. 2 is a vertical cross-sectional view showing the configuration of a modification of the laser beam condensing device according to the first embodiment.

The laser light collecting device 100 in the modified example has a concave mirror 110 and a convex mirror 120 . The laser beam condensing device 100 in this modified example does not have the convex lens 130 . When a light receiving mechanism 51 (FIG. 7), which will be described later, is provided at the position of the convex lens 130 shown in FIG. The light receiving mechanism 51 can sense the laser light that has passed through the concave mirror central opening 113 and the convex mirror central opening 123 formed in the center of the convex mirror main body 121 . By configuring in this way, the laser beam focusing device 100 can be configured with a minimum of equipment.

In addition, below, the case of the laser beam condensing device 100 having the configuration shown in FIG. 1 will be described as an example.

FIG. 3 is a flow chart showing the procedure of the laser beam condensing method according to the first embodiment.

As a laser light condensing method, first, the laser light condensing device 100 is installed (step S01). That is, the laser light collecting device 100 is installed at a position for collecting the laser light from the laser light source 1 (FIGS. 7 to 9). The laser beam focusing device 100 is installed so that the convex mirror 120 is closer to the light source 1 side than the concave mirror 110 is.

Here, the light source 1 may be, for example, a laser oscillator itself that generates and emits laser light, or may be a part that reflects the irradiated laser light.

Next, the laser beam from the light source 1 is reflected by the concave mirror 110 (step S02). If some of the laser light from the light source 1 passes through the concave mirror central opening 113 formed in the center of the concave mirror 110 and the convex mirror central opening 123 formed in the center of the convex mirror main body 121, , part of the laser light passes through the concave mirror central aperture 113 and the convex mirror central aperture 123 .

Next, the laser beam reflected by the concave mirror 110 is reflected by the convex mirror 120 (step S03).

Next, the laser beam reflected by the convex mirror 120 is allowed to pass through the concave mirror central opening 113 (step S04).

Next, the laser light extracted from the concave mirror central opening 113 is focused by a convex lens (step S05).

FIG. 4 is a conceptual first vertical cross-sectional view showing a conventional light collecting method for explaining the effect of the laser light collecting device according to the first embodiment, and FIG. 5 is a conceptual second longitudinal sectional view. A longitudinal sectional view, and FIG. 6 is a conceptual third longitudinal sectional view.

As shown in FIG. 4, a typical example of a conventional light collection method is to collect laser light emitted from a light source 1 by a convex lens 2 and receive it by a laser light receiving section 3 such as a sensor. The light source 1 is, for example, a laser beam exit or an irradiation point where an object is irradiated with the laser beam.

In such a system, there are no restrictions on the size and shape of the light source 1, but the light source 1 is on the optical axis of the convex lens 2, and the laser light emitted within a certain irradiation angle range is condensed. .

On the other hand, if the light source 1 is off the optical axis of the convex lens 2, the laser light cannot reach the laser light receiving section 3 in the positional relationship, for example, as shown in FIG.

Therefore, when the light source 1 is off the optical axis of the convex lens 2, it is necessary to incline the entire optical system and adjust the position of the laser light receiving section 3, as shown in FIG.

FIG. 7 is a conceptual first longitudinal sectional view showing the light receiving state of the laser light receiving device for explaining the effect of the laser light collecting device according to the first embodiment, and FIG. 2, and FIG. 9 is a conceptual third longitudinal sectional view.

In the laser beam focusing device 100 according to this embodiment, a convex mirror 120, a concave mirror 110, and a convex lens 130 are arranged from the side closer to the light source 1 with the optical axis 101 as one. At this time, the convex mirror 120 and the concave mirror 110 are arranged with their convex portions directed in the direction opposite to the light source 1 .

As shown in FIG. 7, when the light source 1 is on the optical axis 101 of the laser beam condensing device 100 of the convex mirror 120, the laser beam passes through the convex mirror central opening 123 and the concave mirror central opening 113. Then, the light passes through the convex lens 130 to be condensed and received by the light receiving mechanism 51 .

FIG. 8 shows a case where the light source 1 is off the optical axis 101. FIG. In this case, the laser beam emitted from the light source 1 is reflected in the direction of the convex mirror 120 by the concave mirror surface portion 112 of the concave mirror 110 . The laser beam reflected by the concave mirror surface portion 112 is reflected again by the convex mirror surface portion 122 of the convex mirror 120 , and most of it reaches the convex lens 130 via the concave mirror central opening 113 of the concave mirror 110 . reach. The laser light reaching the convex lens 130 is condensed and received by the light receiving mechanism 51 .

Furthermore, when the deviation from the optical axis 101 is small, as shown in FIG. , reflected by the concave mirror 110 and the convex mirror 120 and condensed to the convex lens 130 via the central opening 113 of the concave mirror are ensured, and a more stable amount of light can be obtained.

As described above, the laser light collecting device 100 according to this embodiment can efficiently collect laser light.

[Second embodiment]
FIG. 10 is a longitudinal sectional view showing the configuration of a laser light collecting device according to the second embodiment.

The laser light collecting device 100a in the second embodiment is a modification of the first embodiment, and instead of the convex mirror 120 of the laser light collecting device 100 in the first embodiment, a convex mirror 120a have

A magic mirror 125 is used in the convex mirror 120a. The magic mirror 125 transmits the laser beam from the light source 1 side, and reflects the laser beam reflected by the concave mirror 110 on the convex mirror surface portion 122 on the surface facing the concave mirror 110 side.

Except for these points, the second embodiment is the same as the first embodiment.

FIG. 11 is a vertical cross-sectional view showing the operation of the laser beam condensing device according to the second embodiment.

Compared to the operation of the laser beam focusing device 100 in the first embodiment shown in FIG. 9, as shown by the dashed line PX, the laser beam transmits through the magic mirror 125, is reflected by the concave mirror 110, and furthermore is reflected by the convex mirror. As the laser beam reflected by the mirror surface 122 reaches the convex lens 130, the light collecting ability is improved.

[Third embodiment]
FIG. 12 is a vertical cross-sectional view showing the configuration of a laser light collecting device according to the third embodiment.

The laser light collecting device 100b in the third embodiment is a modification of the first embodiment, and instead of the convex mirror 120 of the laser light collecting device 100 in the first embodiment, a convex mirror 120b have

Convex mirror 120 b has a plurality of reflective spheres 127 . The plurality of reflective spheres 127 have an overall shape similar to that of the convex mirror 120 in the first embodiment, and are arranged in one or more layers in the thickness direction. Each reflecting sphere 127 has a reflecting sphere mirror surface portion 128 on its surface, as in the first embodiment.

The plurality of reflecting spheres 127 are held in their mutual positional relationship by, for example, a mesh holding member (not shown).

Except for these points, the second embodiment is the same as the first embodiment.

Although FIG. 12 shows the case where only the convex mirror 120b is composed of a plurality of reflecting spheres 127, the present invention is not limited to this. That is, the concave mirror 110 may instead be composed of a plurality of reflecting spheres. Alternatively, in addition to the convex mirror 120b, the concave mirror 110 may instead consist of a plurality of reflective spheres.

By configuring in this way, it has the same reflecting function as the convex mirror 120 of the first embodiment.

It should be noted that it is also possible to form a gap between the reflecting spheres 127 adjacent to each other without bringing them into close contact with each other. With such an arrangement, similarly to the second embodiment, it is also possible to have the function of transmitting the laser light from the light source 1 to the concave mirror 110 side.

[Fourth embodiment]
FIG. 13 is a longitudinal sectional view showing the configuration of the laser light receiving device according to the fourth embodiment.

A laser beam transmitting/receiving device 200 as a whole system has a laser oscillator 21 , a laser beam focusing device 100 and a laser beam receiving device 210 .

The laser beam transmitting/receiving device 200 is arranged such that the optical axis of the laser beam focusing device 100 is perpendicular to the surface of the measurement object 10 .

The laser light condensing device 100 is similar to that shown in the first embodiment, but may be replaced with the laser light condensing device 100a in the second embodiment or the laser light condensing device 100a in the third embodiment. It may be replaced with the optical device 100b. The same applies to the following embodiments.

The laser light receiving device 210 has a beam splitter 41 and a light receiving mechanism 51 . The beam splitter 41 is arranged with an inclination of 45 degrees with respect to the optical axis 101, reflects the laser beam emitted from the laser oscillator 21 in a direction perpendicular to the optical axis 101 toward the measurement target 10, and reflects the laser light toward the measurement target 10. The laser beam modulated from 10 and returned along the optical axis 101 is transmitted in that direction. A light receiving mechanism 51 receives the laser light from the laser oscillator 21 .

FIG. 14 is a longitudinal sectional view showing the configuration of a modification of the laser light receiving device according to the fourth embodiment. In this modified example, the positional relationship between the laser oscillator 21 and the light receiving mechanism 51 is replaced with each other.

Therefore, since the laser oscillator 21 is on the optical axis 101 , the laser light emitted from the laser oscillator 21 passes through the beam splitter 41 along the optical axis 101 . A laser beam modulated from the measurement target 10 and returned along the optical axis 101 is reflected by the beam splitter 41 in a direction perpendicular to the optical axis 101 and received by the light receiving mechanism 51 .

FIG. 15 is a longitudinal sectional view showing the configuration of another modified example of the laser light receiving device according to the fourth embodiment. In this modified example, the beam splitter 41 is not used, and the irradiation path and the reflection path of the laser beam are separate paths. Further, an interferometer 52 for interferometric measurement of laser light is provided at the rear stage of the light receiving mechanism 51 .

Here, as the interferometer 52, for example, a Michelson interferometer, a homodyne interferometer, a heterodyne interferometer, a Fizeau interferometer, a Mach-Zehnder interferometer, a Fabry-Perot interferometer, a photorefractive interferometer, or the like can be used. A knife edge method is also conceivable as a method other than the interference measurement. The interferometer 52 is for interferometric measurement with respect to the measurement target 10, but is not limited to the configuration of FIG. can be combined with an interferometer. Further, although interference measurement is taken as an example here, necessary devices may be combined according to the purpose of measurement such as spectrum analysis and evaluation of light quantity.

Although these modifications may be used, the case of the system shown in FIG. 13 will be described below.

FIG. 16 is a conceptual vertical cross-sectional view of a conventional example for comparison to explain the first action of the laser light receiving device according to the fourth embodiment. Only one side of the optical system 5 is labeled for the sake of clarity.

In the conventional example, in the optical system 5, the convex lens 2, the beam splitter 4, and the light receiving mechanism 51 are arranged on the optical axis L1. The beam splitter 4 is inclined 45 degrees with respect to the optical axis L1, and the laser oscillator 21 emits laser light to the beam splitter 4 in a direction perpendicular to the optical axis L1.

In the case of the light source P1 on the virtual tangential plane S1 of the measurement target 10, the light receiving mechanism 51 can receive the laser light by arranging the optical system 5 so that the optical axis L1 is perpendicular to the virtual tangential plane S1.

When the position of the light source moves to the light source P2 on the virtual tangential plane S2 of the measurement object 10 and the virtual tangential plane S2 is inclined with respect to the virtual tangential plane S1, in order for the light receiving mechanism 51 to receive the laser light, an optical The system 5 should be arranged so that the optical axis L1 is perpendicular to the imaginary tangent plane S2.

FIG. 17 is a vertical cross-sectional view for explaining the first action of the laser light receiving device according to the fourth embodiment. Note that only one side of the laser light transmitting/receiving apparatus 200 is labeled for easy understanding.

In the case of the light source P1 on the virtual tangential plane S1 of the measurement target 10, the laser light transmitting/receiving device 200 is arranged so that the optical axis 101 is perpendicular to the virtual tangential plane S1, so that the laser light emitted from the light source P1 passes through the convex mirror central opening 123 and the concave mirror central opening 113 to reach the light receiving mechanism 51 .

When the position of the light source moves to the light source P2 on the virtual tangent plane S2 of the measurement object 10 and the virtual tangent plane S2 is inclined with respect to the virtual tangent plane S1, the laser light emitted from the light source P2 is partially passes through the central convex mirror opening 123 and the central concave mirror opening 113 and reaches the light receiving mechanism 51. After being reflected by the concave mirror 110 and the convex mirror 120, the light is condensed by the convex lens 130, and the light receiving mechanism Some reach 51, and the light-gathering ability can be secured.

FIG. 18 is a conceptual vertical cross-sectional view of a conventional example for comparison to explain the second action of the laser light receiving device according to the fourth embodiment.

When the position of the light source, i.e., the position where the laser beam is irradiated, is at the position P1 where the surface roughness of the small surface roughness measurement target 12, that is, the measurement target 10 is relatively small (upper part in FIG. 17) , the amount of light covered by the convex lens 2 .

When the position of the light source, i.e., the position where the laser beam is irradiated, moves to the position P2 where the surface roughness of the large surface roughness measurement target 13, i.e., the measurement target 10 is relatively large (the lower part of FIG. 17 ), the scattering of the laser light irradiated to the surface of the measurement object 10 increases, and as a result, the amount of light entering the convex lens 2 decreases compared to when the light source is at the position P1.

That is, in the case of the conventional optical system, the light-gathering ability largely depends on the roughness of the surface of the measurement target 10 .

FIG. 19 is a longitudinal sectional view for explaining the second action of the laser light receiving device according to the fourth embodiment.

When the position of the light source 1, that is, the position to irradiate the laser beam, is at the position P1 of the small surface roughness measurement target 12, that is, the portion of the measurement target 10 where the surface roughness is relatively small (upper portion in FIG. 18) Next, consider the amount of light covered by the laser beam condensing device 100 .

When the position of the light source 1, i.e., the position where the laser beam is irradiated, moves to the position P2 where the surface roughness of the large surface roughness measurement object 13, i.e., the measurement object 10 is relatively large (lower side of FIG. 18) part), the scattering of the laser light irradiated to the surface of the measurement object 10 increases, but the amount of the spread laser light reflected by the concave mirror 110 increases, so the light amount reaching the convex lens 130 as a whole decreases. is less than in conventional optical systems.

That is, in the case of the conventional optical system, the dependence of the light gathering ability on the roughness of the surface of the measurement target 10 is reduced.

FIG. 20 is a flow chart showing the procedure of the laser beam condensing method according to the fourth embodiment.

First, the laser light collecting device 100 is installed (step S01).

Next, the beam splitter 41, the laser oscillator 21, and the light-receiving mechanism 51 are installed after the laser beam focusing device 100 (step S10). As a result, the laser light transmitting/receiving device 200 is configured.

Next, the laser oscillator 21 emits a laser beam to irradiate the measurement target 10 with the laser beam (step S21). At this time, the laser beam to be irradiated may pass through a concave mirror central opening 113 formed in the concave mirror 110 of the laser beam condensing device 100 and a convex mirror central opening 123 formed in the convex mirror 120. . Alternatively, the light may be irradiated through a path that does not pass through the laser beam condensing device 100 .

Next, the laser beam reflected by the measurement object 10 is focused by the laser beam focusing device 100 (step S31). The details within this step are the same as those described with reference to FIG. 3 in the first embodiment.

Next, the laser light condensed by the laser light condensing device 100 is received by the light receiving mechanism 51 (step S32).

The functions of the laser beam condensing device 100 can be exhibited by the procedure described above.

[Fifth embodiment]
FIG. 21 is a conceptual vertical cross-sectional view showing a laser light receiving device according to the fifth embodiment.

This embodiment is a modification of the fourth embodiment. The laser light transmitting/receiving device 200 including the laser light receiving device 210 in this embodiment further has a galvanometer scanner 35 . Other points are the same as in the fourth embodiment.

The galvanometer scanner 35 is arranged between the laser oscillator 21 and the object 10 to be measured.

In the present embodiment, the galvanometer scanner 35 is used to control the position of the light source on the measurement target 10 , that is, the irradiation point 1 a on the measurement target 10 .

A laser beam is caused to enter the galvanometer scanner 35 from the laser oscillator 21, and the irradiation point 1a on the surface of the measurement object 10 is moved at high speed by controlling the angle of the mirror in the galvanometer scanner 35. FIG. The reflection angle of the reflected light from each irradiation point 1a changes according to the incident angle of the incident light. As described in the description of the fourth embodiment, the laser beam focusing device 100 has little dependency on the angle of the laser beam incident on the laser beam focusing device 100 or the relationship with the optical axis, Since the ability can be maintained, even if the position of the irradiation point 1a changes, the light receiving function of the light receiving mechanism 51 can be maintained at the initial installation position.

In conventional optical systems, it was necessary to devise ways to receive light while changing the angle of the light receiving system, but in this embodiment, it is possible to continuously receive light without moving the optical system on the light receiving side. Therefore, it is effective when high-speed multi-point measurement is required.

[Sixth embodiment]
FIG. 22 is a conceptual longitudinal sectional view showing a laser light receiving device according to the sixth embodiment.

The sixth embodiment is a modification of the first embodiment. A laser light receiving device 210 according to the sixth embodiment has a holding drive mechanism 150 . Other points are the same as the first embodiment.

The holding drive mechanism 150 has a holding portion 151 and a driving portion 152 .

The holding portion 151 is a support structure that holds the laser light collecting device 100 and the light receiving mechanism 51 while maintaining the positional relationship between them. The holding portion 151 is formed with a light receiving opening 151a on the side that receives the laser light from the measurement target side. Between the laser light collecting device 100 and the light receiving mechanism 51, an opening 151b for passing laser light is formed.

The drive unit 152 has a drive source such as an electric motor or a hydraulic mechanism capable of driving in the three axial directions of X, Y and Z or in the three axial directions of R, Θ and Z, and a transmission mechanism. Alternatively, it may be in the form of a robot arm.

This embodiment is effective when the shape of the measurement object 10 changes beyond the range that can be received by the laser beam focusing device 100, and is a mechanism for fine adjustment required in a conventional optical system. and work can be greatly reduced, and stable measurement can be achieved regardless of the measurement target.

[Seventh Embodiment]
FIG. 23 is a vertical cross-sectional view showing the configuration of a laser light receiving device according to the seventh embodiment. FIG. 23 shows a configuration in which the laser beam transmitting/receiving device 200 according to the fourth embodiment is used for ultrasonic measurement.

Laser light receiving device 210 in laser light transmitting/receiving device 200 further includes interferometer 52 , signal recording device 53 , and display device 54 in addition to laser light collecting device 100 and light receiving mechanism 51 . The interferometer 52 measures the Doppler shift of the laser beam reflected by the irradiation point 1a. The signal recording device 53 has an arithmetic unit and a memory, analyzes the detection result by the interferometer 52, and stores and stores the signal received by the light receiving mechanism 51, the detection result by the interferometer 52, and the analysis processing result. A display device 54 displays the contents stored in the signal recording device 53 .

Ultrasonic waves are generated from a piezoelectric element 82 attached to the object 10 to be measured. A piezoelectric element is called an ultrasonic probe, and includes a mechanism for generating ultrasonic waves, a damping material for damping ultrasonic waves, and a front plate attached to the oscillation surface of ultrasonic waves. It becomes the composition which consists of combination. Application of voltage and the like for generating ultrasonic waves from the piezoelectric element 82 are performed by the ultrasonic generator 81 .

The ultrasonic waves generated from the piezoelectric element 82 are reflected by the defect 10d inside the measurement target 10, reach the surface of the measurement target 10, and vibrate the surface.

The vibrating surface is irradiated with a laser beam, the Doppler shift of the reflected laser beam is detected using an interferometer 52, and the surface displacement at the irradiation point 1a on the surface of the measurement target 10 is measured. The measured signal is analyzed by the signal recording device 53 and the result is displayed on the display device 54 .

FIG. 24 is a longitudinal sectional view showing the configuration of a laser light receiving device in a modified example of the seventh embodiment.

This modification differs only in the part that generates ultrasonic waves, and has a pulse laser oscillator 83 and an optical mirror 84 in place of the ultrasonic wave generator 81 and the piezoelectric element 82, and emits the laser emitted from the pulse laser oscillator 83. , the optical mirror 84 is used to irradiate the object 10 to be measured.

Nd:YAG lasers, carbon dioxide gas lasers, Er YAG lasers, titanium sapphire lasers, alexandrite lasers, ruby lasers, dye lasers, excimer lasers, and the like can be used as pulse lasers. Also, a laser light source other than these may be used.

In addition, although the transmission of the laser light in the space has been shown by the optical mirror 84, a method of transmission by an optical fiber, a method of scanning by a galvanometer scanner, or the like may be used.

When the measurement object 10 is irradiated with a laser having a pulse width of several nanoseconds, ultrasonic waves can be excited with the irradiation point 1b as a sound source. The incident ultrasonic wave propagating into the measurement target 10 is reflected by the defect 10d, and the surface of the measurement target 10 vibrates due to the arrival of the reflected ultrasonic wave. Subsequent processes are the same as those shown in FIG.

As described above, according to the present embodiment, stable ultrasonic flaw detection is possible without depending on the surface state of the object 10 to be measured.

FIG. 25 is a flow chart showing the procedure of the laser beam condensing method according to the seventh embodiment.

Steps S01 and S10 are the same as in the fourth embodiment described with reference to FIG.

Following step S10, ultrasonic waves are made incident on the measurement object 10 (step S41).

Steps S21, S31, and S32 performed after step S41 are the same as in the fourth embodiment described with reference to FIG.

Through the procedure described above, the function of the laser beam focusing device 100 can be exhibited even in ultrasonic flaw detection.

[Other embodiments]
Although the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention.

Moreover, you may combine the characteristic of each embodiment. In addition, the embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention.

The embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and its equivalents.

Reference Signs List 1 Light source 1a, 1b Irradiation point 2 Convex lens 3 Laser receiver 4 Beam splitter 5 Optical system 10 Measurement object 10a, 10d Defect 12 Small surface roughness measurement Object 13 Large surface roughness measurement object 21 Laser oscillator 35 Galvano scanner 41 Beam splitter 51 Light receiving mechanism 52 Interferometer 53 Signal recording device 54 Display device 81 Super Sound wave generator 82 Piezoelectric element 83 Pulse laser transmitter 84 Optical mirror 100, 100a, 100b Laser light collecting device 101 Optical axis 110 Concave mirror 111 Concave mirror main body 112 Concave mirror mirror surface portion 113 Concave mirror central opening 120, 120a, 120b Convex mirror 121 Convex mirror main body 122 Convex mirror mirror surface portion 123 Convex mirror central opening 125 Magic mirror , 127... reflecting sphere, 128... reflecting spherical mirror surface part, 130... convex lens, 150... holding drive mechanism, 151... holding part, 151a, 151b... opening, 152... drive unit, 200... laser beam transmitting/receiving device, 210... laser light receiving device

Claims (8)

A laser light collecting device for condensing the laser light by arranging the optical axis perpendicular to the surface of the light receiving mechanism for guiding the laser light to the light receiving mechanism for detecting the laser light from the light source, ,
a concave mirror having a central concave mirror opening formed in the center;
It is located on the opposite side of the convex portion of the concave mirror, is arranged in the center with the convex portion facing in the same direction as the concave mirror, and on the optical axis of the concave mirror so that its own optical axis overlaps. a convex mirror having a central opening of the convex mirror;
with
The position of the convex mirror on the optical axis is closer to the concave mirror side than the focal position of the concave mirror, and the diameter of the concave mirror is larger than the diameter of the convex mirror.
A laser beam condensing device characterized by: 2. The laser beam focusing device according to claim 1, wherein the diameter of the central opening of the concave mirror is smaller than the diameter of the central opening of the convex mirror. 3. The lens according to claim 1, further comprising a convex lens arranged on the optical axis on the opposite side of the convex mirror with the concave mirror interposed therebetween so that its own optical axis overlaps with the optical axis. laser beam focusing device. 4. The laser beam focusing device according to claim 1, wherein the convex mirror has an aspheric outer surface and a mirror surface. 4. The convex mirror according to any one of claims 1 to 3, wherein the outer side of the convex mirror has an aspherical shape, and the laser beam is transmitted from the concave side to the convex side and is reflected by the surface of the convex side. 10. The laser beam condensing device according to the above item. 6. The laser light condensing device according to claim 4, wherein the convex mirror has a plurality of spherical bodies arranged along the aspherical shape, each of which has a surface capable of reflecting the laser light. light device. a holding unit that holds the concave mirror and the convex mirror;
a driving unit for adjusting the direction and position of the holding unit;
7. The laser beam focusing device according to any one of claims 1 to 6, further comprising a holding and driving mechanism having a . a laser beam focusing device according to any one of claims 1 to 7;
an interferometer for interferometrically measuring the laser light;
A laser light receiving device comprising:

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