JPH05107037A - Planar-luminous-flux projecting apparatus for measuring optical cutting beam - Google Patents

Abstract

PURPOSE:To obtain a planar-luminous-flux projecting apparatus, which projects radially expanding planar luminous flux toward the surrounding wall surface of an object to be measured such as the surrounding wall surface of a tunnel, and can form the optical cutting beam, which is obtained by narrowing the luminous flux into the narrow width of about several mm and has the high optical power density, on the surrounding wall surface of the object to be measured. CONSTITUTION:As a light source, a high-output type semiconductor laser 2 is used. Within a YZ plane, the laser beam from the semiconductor laser 2, which is regarded as the point light source, is collimated through a collimate lens 3. Then, the thickness of the beam is expanded through a cylindrical-surface concave lens 7a and a cylindrical-surface convex lens 7b. Converging property is imparted to the thickness-expanded laser beam. The laser beam is guided to a conical reflecting mirror 6. In an XZ plane, converging property is imparted to the divergent laser beam, which has passed through the collimating lens 3, with a cylindrical surface convex lens 8. The laser beam is guided to the conical reflecting mirror 6. The direction of the laser beam formed in this way is changed with the conical reflecting mirror 6. Thus, the radially expanding planar luminous flux S is projected toward the surrounding wall surface of a tunnel T.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat-beam light-projecting device for light-cutting measurement, which is used for measuring, for example, a tunnel cross section by a light-cutting method. The present invention relates to an improvement of a flat-beam light-projecting device for light-cutting measurement, which projects a flat light beam spreading radially toward a wall surface to generate a ring-shaped light cutting line along the peripheral wall surface of a measurement target object. is there.

[0002]

2. Description of the Related Art As is well known, when a tunnel is excavated, a light section method is used to determine whether the cross-sectional shape of the tunnel is as designed or to maintain or inspect the existing tunnel. The shape is being measured. The cross section of this tunnel is measured by projecting a plate-like light beam that spreads radially from the inside of the tunnel toward the entire circumference of the tunnel peripheral wall surface to generate a ring-shaped light cutting line along the circumferential direction on the tunnel peripheral wall surface. Then, the light cutting line is imaged by a television camera, and the position of the light cutting line on the obtained light cutting image is detected to obtain the sectional shape of the tunnel in the predetermined coordinate system.

As a light projecting device used for such tunnel cross-section measurement, there is a device as disclosed in Japanese Utility Model Laid-Open No. 62-67212. FIG. 6 is a cross-sectional plan view of a floodlighting device for measuring tunnel cross-section according to this conventional technique.

As shown in FIG. 6, the conventional tunnel cross-section measurement light projecting device 51 is constructed as follows.
A parabolic reflector 53 is coaxially connected to the rear end of the horizontally oriented cylindrical body 52, and the outer sides of the cylindrical body 52 and the parabolic reflector 53 are covered with a casing 55 via a cushioning material 54. .. An end plate 57 is fixed to the front ends of the cylindrical body 52 and the casing 55 via a rectangular transparent tube 56 made of glass or the like, and the rectangular transparent tube 56 allows the cylindrical body 52 and the parabolic reflector 53 to be fixed. A slit-shaped opening 56a is formed to allow the passage of light over the entire circumference along a plane orthogonal to the axis of the.

A lamp light source 58 such as a halogen lamp is disposed at the focal position of the parabolic reflector 53, and inside the cylindrical body 52, as shown in the figure, in front of the lamp light source 58. In, the first convex lens 59 and the second convex lens 60 are coaxially arranged in a state where the front focal point F of the first convex lens 59 and the rear focal point F of the second convex lens 60 are aligned.

At the position of the focal point F between the first convex lens 59 and the second convex lens 60, a slit plate 61 orthogonal to the axis of the cylindrical body 52 is arranged, and the slit plate 61 is provided at the center thereof. Has a slit hole that is small at the focal point F. Further, in order to redirect the light passing through the second convex lens 60 to a right angle and project it as a flat light flux that spreads radially from the slit-shaped opening 56a, a conical reflecting mirror 62 is provided at the center of the end plate 57. It is arranged.

In the tunnel cross-section measuring light projector 51 thus constructed, a part of the light beam emitted from the lamp light source 58 is reflected by the parabolic reflector 53 to become a parallel light beam.
After being refracted by the first convex lens 59 and converged at the focal point F, the second lens
The convex lens 60 forms parallel rays. The non-converging light that does not converge to the focal point F after passing through the first convex lens 59 is blocked by the slit plate 61. Then, the parallel light rays that have passed through the second convex lens 60 are converted in direction by the conical reflecting mirror 62 and projected as a flat light flux that spreads radially toward the tunnel peripheral wall surface T.

In the above projector 51, a parabolic reflector
It is the lamp light source that is reflected by 53 and becomes parallel rays.
Of the optical power emitted from 58 in all solid angles, it is the optical power emitted into the effective condensing solid angle Ω, as shown in FIG. Further, the width d of the ring-shaped light cutting line C (thickness of the flat light flux on the tunnel circumferential wall surface) generated along the circumferential direction on the circumferential wall surface of the tunnel by projecting the radially spread flat light flux is Size ε (lamp light source
58 eg filament size) and parabolic reflector 5
3, the convex lens 59 and 60, the optical system consisting of the slit plate 61, and the distance L from the conical reflecting mirror 62 to the tunnel peripheral wall surface are determined by the geometrical relationship.

In the light projecting device 51, the slit plate 61
Image size ε of the lamp light source 58 at the slit hole position of
′ Is a focal length of the first convex lens 59 is f ₁₀ , a parabolic reflector
If the focal length of 53 is A, then ε ′ = ε · (f ₁₀ / A). Here, if the hole diameter φ of the slit plate 61 is designed to be smaller than this ε ′, the light emitted from the light source having the size φ is converted into parallel rays by the second convex lens 60, and the parallel rays are reflected by the conical rays. By being redirected by the mirror 62 and projected as a flat light flux, a ring-shaped light cutting line C having a width d is generated on the circumferential wall surface of the tunnel.

The width d of the light cutting line C is determined by the second convex lens 60.
If the distance between the conical reflecting mirror 62 and the conical reflecting mirror 62 is sufficiently short, L is the distance between the conical reflecting mirror 62 and the circumferential wall of the tunnel, and the focal length of the second convex lens 60 is f ₂₀ , then d = φ · (L / f ₂₀ ). Further, of the optical power of the lamp light source 58, the efficiency η of the optical power that contributes to the formation of the flat light flux projected on the circumferential wall surface of the tunnel is η = (Ω / 4π) · {φ / [ε · (f
₁₀ / A)]} ² .

[0011]

In the above-mentioned conventional floodlight device for measuring tunnel cross-section, a lamp light source such as a halogen lamp is used as a light source, and a lens system is used to obtain light from this lamp light source by using a lens system. Since a part of the light beam is made to be parallel rays, it is difficult to obtain a light cutting line having a high light power density, which is obtained by narrowing the light beam with a narrow width on the circumferential wall surface of the tunnel. Therefore, when an optical cutting line generated on the peripheral wall surface of the tunnel is imaged by a television camera for tunnel cross-section measurement, it is difficult to obtain an optical cutting line image showing a step pulse-like light intensity distribution that sharply changes greatly. For example, when the optical reflectance of the tunnel peripheral wall surface is low due to the adhesion of "moss", there is a drawback that the measurement accuracy of the tunnel cross section becomes poor.

The present invention has been made in order to solve the above-mentioned conventional drawbacks, and is a plate-like luminous flux that spreads radially toward the peripheral wall surface of a measuring object such as a tunnel whose shape is to be measured by the optical cutting method. In a flat-beam light-projection device for light-cutting measurement for projecting light, it is possible to generate a light-cutting line having a high optical power density by narrowing the light flux on a peripheral wall surface of a measurement target such as a tunnel peripheral wall surface. An object of the present invention is to provide a flat-beam light-projecting device for measuring light-section, which enables accurate measurement of a tunnel cross-section and the like.

[0013]

In order to achieve the above-mentioned object, the flat-beam light-projecting device for measuring light-section according to claim 1 comprises:
A casing having a cylindrical shape and a light passage window portion of a predetermined width that allows passage of light over substantially the entire circumference at a part of the tip side thereof, a light source arranged at a rear portion of the casing, and inside the casing. Optical means disposed in front of the light source for directing a light beam from the light source forward, and an optical means disposed inside the light passing window portion for changing the direction of the light beam from the optical means and transmitting the light. A light cutting device that has a conical reflecting mirror that projects as a flat light beam that spreads radially from the window for projection, and projects a flat light beam that spreads radially toward the peripheral wall surface of the measurement target whose shape should be measured by the light cutting method. In the measurement flat-plate light-beam projector, the light source has an emission optical axis in the Z-axis direction which is the axial center line direction of the casing, a direction parallel to the pn junction surface as seen from the laser beam emission surface, and an X-axis direction. Seen from the laser beam emission surface The semiconductor laser is arranged so that the direction perpendicular to the n-junction surface becomes the Y-axis direction, the optical means is arranged in front of the semiconductor laser, and the laser beam from the semiconductor laser is incident thereon. Collimating lens, and arranged in front of this collimating lens,
In the YZ plane, the thickness of the laser beam that is collimated by the collimator lens is expanded, and the laser beam whose thickness is expanded is converged, while in the XZ plane, the laser beam has a divergence property that has passed through the collimator lens. It is characterized in that it is constituted by a condensing lens system for giving a converging property to a laser beam.

According to a second aspect of the present invention, there is provided a flat light beam projecting apparatus for measuring light section according to the flat light projecting apparatus for measuring light section according to claim 1, wherein the condenser lens system and the conical reflecting mirror are provided between the condensing lens system and the conical reflecting mirror. It is provided with a circular aperture having a circular opening for making a laser beam that has passed through the condenser lens system into a circular section light beam.

[0015]

The flat-beam light-projecting device for light-section measurement according to the present invention uses a semiconductor laser as a light source. The laser beam emitted from the light emitting point (light emitting region) of the active layer in the pn junction of the semiconductor laser is parallel to the pn junction surface when viewed from the laser beam emission surface, when the direction of the emission optical axis is the Z axis direction. The divergence angle (divergence angle) differs between the direction (X-axis direction) and the direction perpendicular to this (Y-axis direction).
In particular, in a high-power type semiconductor laser, as shown in FIG. 5, since a large number of light emitting points are formed in the active layer along the pn junction surface, the directivity of the emitted laser beam is high. Is different between the YZ plane and the XZ plane.

Therefore, when the laser beam emitted from the semiconductor laser is to be converted into parallel rays by the collimator lens, the size of the light emitting point as the light source is small in the YZ plane in FIG. However, in the XZ plane in FIG. 5, since the size due to the light emitting point is larger than that in the YZ plane, parallel rays close to ideal are not obtained, and the light has divergence.

Therefore, since the flat-beam light-projecting device for light-section measurement according to the present invention is constructed as described above, Y
In the Z plane, a laser beam from a semiconductor laser, which can be regarded as a point light source, is collimated by a collimator lens, and then a converging lens system gives a laser beam whose beam thickness has been expanded. While being guided to the conical reflecting mirror, in the XZ plane, the divergent laser beam that has passed through the collimating lens is converged by the converging lens system and guided to the conical reflecting mirror. Since the direction of the laser beam made in this way is changed by a conical reflecting mirror and projected as a flat light beam that spreads radially toward the peripheral wall surface of the measurement object such as the tunnel peripheral wall surface, the measurement of the tunnel peripheral wall surface etc. It is possible to generate an optical cutting line having a high optical power density by narrowing the light flux to a narrow width on the peripheral wall surface of the object.

A circular aperture is preferably arranged between the condenser lens system and the conical reflecting mirror. The laser beam that has passed through the condenser lens system is shaped into a light beam with a circular cross-section by a circular aperture, and the laser beam that has a circular cross-section is projected onto a conical reflecting mirror. It is possible to project a flat-plate-shaped light beam having no local bulge in the thickness toward it.

[0019]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a structural explanatory view of a flat beam light projecting apparatus for light cutting measurement according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining an operation in a YZ plane of the flat light beam projecting apparatus for light cutting measurement shown in FIG. FIG. 3 is a diagram for explaining the operation in the XZ plane of the flat-beam light-projection device for light-section measurement shown in FIG.

In FIG. 1, reference numeral 1 denotes a cylindrical casing which is arranged so that its axial center direction is the longitudinal direction of the tunnel. The casing 1 is provided with a light-passing window portion 1a having a predetermined width and made of glass or the like that allows light to pass through the entire circumference on a part of the front end side thereof. As shown in the figure, inside the casing 1, a high power semiconductor laser 2, a collimating lens 3, a condenser lens system 4, a circular aperture 5 and a cone are arranged in this order from the rear portion thereof toward the light passage window portion 1a. The shape-reflecting mirror 6 and the shape-reflecting mirror 6 are coaxially arranged by a mounting means (not shown).

The high-power type semiconductor laser 2 is, for example, 1
It has an output power of about watts, and as shown in the figure, the emission optical axis is in the Z-axis direction, which is the axial center line direction of the casing 1, and in the direction parallel to the pn junction surface when viewed from the laser beam emission surface. Pn in the X-axis direction as seen from the laser beam emission surface
It is arranged such that the direction perpendicular to the joint surface is the Y-axis direction. In FIG. 1, for example, the Z-axis direction corresponds to the longitudinal direction of the tunnel, the X-axis direction corresponds to the lateral direction of the tunnel, and the Y-axis direction corresponds to the vertical direction of the tunnel.

The collimator lens 3 on which the laser beam from the high power semiconductor laser 2 is incident has a focal length f ₁ . In this embodiment, the collimator lens 3 has an aspherical shape, f ₁ = 5.5 mm, and numerical aperture NA = 0.55.

As shown in the figure, the condenser lens system 4 includes a first cylindrical concave lens 7a and a second cylindrical convex lens 7b arranged in a posture having a lens action in the Y-axis direction, and a lens in the X-axis direction. It is configured by a third cylindrical convex lens 8 disposed on the side of the light passing window portion 1a, which is in front of the second cylindrical convex lens 7b in a posture having an action.

The first concave concave lens 7a having a negative focal length f ₂ and the second convex convex lens 7b having a convergent system having a positive focal length f ₃ are a beam extractor in the YZ plane (Y-axis direction). To act as a panda,
In the YZ plane, the thickness of the laser beam made into the parallel rays by the collimator lens 3 is expanded, and the second cylindrical convex lens 7b is added to the laser beam whose thickness is expanded.
To give convergence. The distance between the principal surfaces of the first concave concave lens 7a and the second convex convex lens 7b is
a ₂ is disposed so as to satisfy the relationship _{a 2 = f 2 + f 3} .
In this example, f ₂ = −200 mm, f ₃ = 1000 mm, and a ₂ =
It is set to 800 mm.

The third cylindrical convex lens 8 of the other converging system lens that constitutes the condensing lens system 4 converges the divergent laser beam that has passed through the collimating lens 3 in the XZ plane (X-axis direction). It is for giving. Assuming that the distance between the third cylindrical convex lens 8 and the conical reflecting mirror 6 is sufficiently short, the focal length is f ₄ , and the distance between the conical reflecting mirror 6 and the tunnel peripheral wall surface T is L, the main collimating lens 3 It is arranged so that the distance a from the surface satisfies the relationship of 1 / f ₄ = (1 / a) + (1 / L). In this example, f ₄
= 1000 mm, L = 4 m, and a = 1400 mm. Since the first concave cylindrical lens 7a is arranged at a position a ₁ = 400 mm from the main surface of the collimator lens 3, the main convex surface of the third convex cylindrical lens 8 and the second convex convex lens 7b of the second cylindrical surface The distance a ₃ is a ₃ = 200 mm.

The circular aperture 5 is for making a laser beam, which will be described later, which has passed through the third cylindrical convex lens 8 of the condensing lens system 4 into a circular light flux in section, and is a conical lens which will be described later with the third cylindrical convex lens 8. It is arranged between the circular reflecting mirror 6 and a circular opening. The collimator lens 3, the condenser lens system 4 and the circular aperture 5 constitute an optical means.

The conical reflecting mirror 6 is for redirecting a laser beam, which will be described later, which has passed through the circular aperture 5 and projecting it as a flat light beam S radially spreading from the light passing window portion 1a. It is arranged inside the window part 1a and has an apex angle of 90 °.

Next, the operation in the YZ plane of the flat-beam light-projecting device for light-section measurement configured as described above will be described with reference to FIG. In the YZ plane, the high power semiconductor laser 2 according to this embodiment has a light emitting point size of 1 μm and an outgoing beam divergence angle θ _Y of θ _Y = 40 °. Therefore, the laser beam from the high-power semiconductor laser 2 is made into a near-ideal parallel beam having a thickness D _1Y by the collimator lens 3. This thickness D _1Y is D _1Y
= 2 · f ₁ · tan (θ _Y / 2), and in this embodiment, D _1Y = 4 mm.

The laser beam made into parallel rays having the thickness D _1Y by the collimator lens 3 is, as shown in the figure,
The thickness is expanded to D _2Y by the first concave lens 7a and the second convex lens 7b. The thickness D _2Y is D _2Y =
Given by M · D _1Y , and in this embodiment, M = | f ₃ / f ₂ |
Therefore, D _2Y = 5 × D _1Y = 20 mm.

The laser beam whose thickness is expanded to D _2Y is guided to the circular aperture 5 through the second convex lens 7b of the converging system lens, and is converted into a circular luminous flux by the circular aperture 5 so as to have a conical reflecting mirror. 6 will be projected. Therefore, on the circumferential wall T of the tunnel in the Y-axis direction (vertical direction of the tunnel), the diffraction limit (L = 4 m is 0.4
It is possible to generate a light section line C having a width d _Y that can be narrowed to (mm).

Next, the operation in the XZ plane of the flat-beam light-projecting device for light-section measurement configured as described above will be described with reference to FIG. In the XZ plane, the high power semiconductor laser 2 according to this embodiment has a light emitting point (light emitting region) of 100 μm and an outgoing beam divergence angle θ _X.
Has θ _X = 10 °. Therefore, since the light emitting region is large, the laser beam from the high power semiconductor laser 2 is
Even if the collimating lens 3 is used, the parallel rays are not close to ideal. In other words, the state is equivalent to that there is a virtual light emitting point of size D _X at the main surface position of the collimator lens 3. The size D _X of the virtual light emitting point is D _X = 2 · f ₁ · tan (θ _X
/ 2), and in this example, D _X = 0.8 mm.

Therefore, as described above, the third cylindrical convex lens 8 of the converging system lens having a lens action in the XZ plane satisfies the relationship of 1 / f ₄ = (1 / a) + (1 / L). Since the tunnel peripheral wall surface T in the X-axis direction (the left-right direction of the tunnel) has a width d _X = D _X
A light cutting line C having (L / a) can be generated. In this example, a width d _X = 2.3 mm can be obtained.

As described above, the high-power semiconductor laser 2 is used as the light source, and the laser beam from the high-power semiconductor laser 2 which can be regarded as a point light source is collimated by the collimator lens 3 in the YZ plane. First cylindrical concave lens 7a
And the second cylindrical convex lens 7b enlarges the thickness of the beam and guides the laser beam having the enlarged thickness to the conical reflecting mirror 6 while converging the laser beam, while in the XZ plane,
The divergent laser beam that has passed through the collimating lens 3 is converged by the third cylindrical convex lens 8 and guided to the conical reflecting mirror 6, and the direction of the laser beam thus formed is changed by the conical reflecting mirror 6. Since the light is projected as a flat plate-like light flux S that spreads radially toward the tunnel peripheral wall surface T, the width of the light cutting line obtained in the past was about several tens of millimeters, whereas This is the case when it is possible to generate a light cutting line with a high width of several mm in which the light power is narrowed down to a narrow width on the wall surface T, and the optical reflectance of the tunnel peripheral wall surface is low due to adhesion such as "moss". However, it is possible to accurately measure the tunnel cross section by the optical cutting method.

Further, a circular aperture 5 is arranged between the third cylindrical convex lens 8 and the conical reflecting mirror 6, and the laser beam which has passed through the condenser lens system 4 has a circular sectional shape by the circular aperture 5. Since the laser beam having a circular cross section is projected onto the conical reflecting mirror 6, a flat light beam having no local expansion in the thickness toward the tunnel peripheral wall surface T is formed. Can be projected.

FIG. 4 is an explanatory view of the configuration of a flat beam projecting device for measuring light section according to another embodiment of the present invention. In FIG. 4, 11 is a spherical lens. This spherical lens 11
This is a replacement of the second cylindrical convex lens 7b and the third cylindrical convex lens 8 in FIG. Since the two cylindrical lenses 7b and 8 in FIG. 1 have a combination in which the focal lengths are the same and the directions of the central axes of the cylindrical surfaces are perpendicular to each other, they are replaced with the single spherical lens 11. be able to. Other configurations are the same as those shown in FIG.

In this embodiment, the spherical lens 11 has a focal length of 1000 mm, and the first cylindrical concave lens 7a having a focal length f ₂ = -200 mm and the spherical lens 11 are the same as in FIG. And the distance a ₂ between the principal surfaces is a ₂ = f ₂ + 1000mm = 800
It is arranged so as to satisfy the mm relationship. Further, the spherical lens 11 and the collimator lens 3 are arranged so that the distance a between their principal surfaces is a = 1400 mm. Therefore,
The first cylindrical concave lens 7a is arranged at a position a ₁ = 600 mm from the main surface of the collimator lens 3. Even in the flat-beam light-projection device for light-section measurement configured as described above,
In the same manner as shown in FIG. 1 above, it is possible to generate a light cutting line having a width of several mm with a high optical power density by narrowing a light beam on the tunnel peripheral wall surface T, and to perform optical reflection on the tunnel peripheral wall surface. Even if the rate is low due to adhesion such as "moss", it is possible to accurately measure the tunnel cross section by the optical cutting method.

As one of the maintenance and inspection works in railways, in order to know the maintenance time accurately by checking the secular change of the structures around the railway such as tunnels, bridges, platforms, etc. The three-dimensional position coordinates of the side of the structure along the trajectory are obtained and the three-dimensional shape is measured. The flat-beam light-projecting device for light-section measurement according to the present invention can be used for the above-mentioned measurement including a tunnel.

[0038]

As described above, according to the flat-beam light-projecting device for light-section measurement according to the present invention, as the light source, the emission optical axis is the Z-axis direction (for example, the longitudinal direction of the tunnel whose cross-section is to be measured) and the laser. The direction parallel to the pn junction surface when viewed from the beam emission surface is the X-axis direction, and pn when viewed from the laser beam emission surface
A semiconductor laser arranged so that the direction perpendicular to the bonding surface is the Y-axis direction is used. In the YZ plane, a laser beam from the semiconductor laser that can be regarded as a point light source is collimated by a collimator lens and then collected. The optical lens system expands the thickness of the beam and guides the laser beam with the expanded thickness to the conical reflecting mirror while converging the laser beam. On the other hand, in the XZ plane, the laser beam has a divergent property after passing through the collimating lens. The beam is guided to a conical reflecting mirror by converging it with a condensing lens system, and the direction of this laser beam is changed by the conical reflecting mirror to radiate toward the peripheral wall surface of the measurement object such as the tunnel peripheral wall surface. Since it is designed to project as a flat light beam that spreads over a wide area, the light beam is narrowed to a narrow width on the peripheral wall surface of the object to be measured and has a high optical power density of several millimeters.
A degree of light cutting line can be generated. With this, when measuring the tunnel cross section by the optical cutting method,
Even if the optical reflectance of the tunnel peripheral wall surface is low due to the adhesion of "moss" or the like, the tunnel cross section can be accurately measured.

Further, a circular aperture is arranged between the condenser lens system and the conical reflecting mirror, and the laser beam passing through the condenser lens system is adjusted into a luminous flux having a circular cross section by this circular aperture. Since the laser beam, which has a circular cross-section, is projected onto the conical reflecting mirror, it projects a flat plate-like luminous flux that does not locally expand in thickness toward the peripheral wall of the measurement object such as the tunnel peripheral wall. can do.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a flat-plate light-beam projecting device for light-section measurement according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation in the YZ plane of the flat-beam light-projection device for light-section measurement shown in FIG.

FIG. 3 is a diagram for explaining the operation in the XZ plane of the flat-beam light-projection device for light-section measurement shown in FIG.

FIG. 4 is a structural explanatory view of a flat-beam light-projecting device for light-section measurement according to another embodiment of the present invention.

FIG. 5 is a diagram for explaining a high power semiconductor laser.

FIG. 6 is a cross-sectional plan view of a tunnel cross-section measurement light projecting device according to a conventional technique.

[Explanation of symbols]

1 ... Casing 1a ... Light-passing window 2 ... High-power semiconductor laser 3 ... Collimating lens 4 ... Focusing lens system
5 ... Circular aperture 6 ... Conical reflecting mirror 7a ... First cylindrical concave lens 7b ... Second cylindrical convex lens 8 ... Third cylindrical convex lens 11 ... Spherical lens T ... Tunnel peripheral wall surface S ...
Plate-shaped luminous flux C ... Light cutting line

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuharu Kami 2-26-3-416, Kojidai, Nishi-ku, Kobe (72) Inventor Katsuhiko Fujii 2-8-2 Jusohonmachi, Yodogawa-ku, Osaka (72) Inventor Nishimoto Yoshiro 7-18, Takenodai 5-chome, Nishi-ku, Kobe (72) Inventor Yuichiro Goto 1-1-4 Migatadai, Nishi-ku, Kobe

Claims (2)

[Claims] 1. A casing having a cylindrical shape and having a light passage window portion of a predetermined width which allows passage of light over substantially the entire circumference at a part of the tip side thereof, and a light source arranged in the rear portion of the casing. An optical means disposed in front of the light source in the casing for directing a light beam from the light source forward; and a light beam disposed from inside the light passing window portion for changing the direction of the light beam from the optical means. And a conical reflecting mirror that projects as a flat light beam that radially spreads from the light passing window, and a flat light beam that spreads radially toward the peripheral wall surface of the measurement target whose shape is to be measured by the light cutting method. In the flat-beam light-projection device for light-section measurement for projecting light, the light source emits light in the Z-axis direction, which is the axial direction of the casing, and in a direction parallel to the pn junction surface when viewed from the laser beam emission surface. Is the X-axis direction, laser beam The semiconductor laser is arranged such that the direction perpendicular to the pn junction surface when viewed from the projecting surface is the Y-axis direction, and the optical means is arranged in front of the semiconductor laser. A collimator lens on which a laser beam is incident, and a laser beam which is arranged in front of the collimator lens and which is made into parallel light by the collimator lens in the YZ plane, is expanded, and a laser beam having this expanded thickness is formed. And a converging lens system for converging the divergent laser beam that has passed through the collimating lens in the XZ plane while converging. Light equipment. 2. In addition to the collimator lens and the condenser lens system, a laser beam that has passed through the condenser lens system between the condenser lens system and the conical reflecting mirror is changed into a circular section light beam. The flat beam projector for optical cutting measurement according to claim 1, further comprising a circular aperture having a circular opening for the purpose.