JP4414183B2 - Laser beam transmitter / receiver - Google Patents

Description

  The present invention relates to a laser beam transmitter / receiver used in, for example, an automatic monitoring device that detects the position and size of an object existing in a predetermined space.

  Conventionally, for example, in order to identify an object or the like that has entered a space to be monitored, a laser beam is irradiated so as to scan the space in a multidimensional manner, and the object is based on information on return light from the object. There is known an automatic monitoring device configured to be able to detect the position and size (see Patent Document 1 below). Such an automatic monitoring device includes a laser beam sending optical system for sending a laser beam emitted from a light source unit, a scan mirror for reflecting the inside of the space in a multidimensional manner, and a return light from the object. A light receiving element for receiving light, and a laser beam transmitting / receiving device including a condensing lens for condensing the return light on the light receiving surface of the light receiving element are provided.

  One type of such a device is known as a “coaxial type”. In this "coaxial system type", the laser beam emitted from the light source unit is irradiated from the light source unit through the scan mirror to the space and the laser beam reflected from the object in the space is received from the object. In this type, the optical paths leading to the elements overlap each other halfway.

  However, in this “coaxial system type”, the scattered light generated at the interface of the half mirror and the scan mirror arranged on the optical path may be guided to the light receiving element. A solved laser beam transmitter / receiver has been devised and disclosed (Patent Document 2 below). That is, the one disclosed in Patent Document 2 uses a perforated reflection mirror or a minute reflection mirror as an optical path separation member that separates an optical path of return light from an optical path of laser light from a light source unit. For this reason, the problem that occurs when using a half mirror as an optical path separating member as in the prior art, that is, scattered light is generated at the interface of the half mirror when the laser light from the light source passes through the half mirror. In addition, it is possible to prevent the problem that the scattered light enters the light receiving element through the condenser lens, and it is possible to further improve the S / N ratio.

JP 2000-149154 A Japanese Patent Application No. 2002-324143

  Incidentally, in the optical system of the automatic monitoring apparatus as described above, a semiconductor laser light source is usually used as a light source in order to achieve a compact and inexpensive configuration. A general semiconductor laser light source is a single stripe, and its light emitting surface has a size of about 1 μm × 3 μm and emits light from one point. For this reason, a relatively simple configuration such as a plurality of spherical lenses or an aspherical single lens is used for the laser light transmitting optical system.

  However, the output of a single stripe semiconductor laser light source is about 6 W at most, and when a higher output is required, a laser light source in which a large number of light emitting points are arranged in a row (or a plurality of rows), for example, the single stripe semiconductor laser light source described above. It is necessary to use a laser light source having an array structure in which ones are arranged in one row (or a plurality of rows). The size of the light emitting surface of such a laser light source has a line shape of, for example, about 1 μm × 150 μm. Further, the beam divergence angle (full angle) in the major axis direction and the minor axis direction of the light emitting surface is greatly different from about 10 degrees in the former and about 30 degrees in the latter. For this reason, if a simple lens configuration such as a plurality of spherical lenses or an aspherical single lens as described above is used as the optical system for laser beam transmission, the laser beam is diffused particularly in situations where a distant object should be irradiated. Therefore, no matter how high the output is, there is a problem that the return light from the object becomes weak and the detection accuracy cannot be improved.

  That is, in the automatic monitoring apparatus as described above, the area of the reflection surface of the scan mirror used is small, and the distance from the light source unit to the object in the space is long, so the light of the laser beam reflected from the object In general, the intensity is attenuated to a level of tens of millions or less of the level emitted from the light source, and in order to improve the detection accuracy, it is necessary to disperse the laser beam without dispersing the laser beam. Irradiation is a problem.

  Furthermore, in the automatic monitoring apparatus as described above, effective signal light is weak, so noise countermeasures are important. As a countermeasure against noise, it is important to reduce the beam diameter from the above-described optical path separating member to the transparent cover of the window part from which laser light is emitted toward the space.

  The present invention has been made in view of the above circumstances, and can irradiate a distant object while irradiating laser light from a semiconductor laser light source in which light emitting points are arranged in a row while suppressing diffusion thereof, and an optical path separating member An object of the present invention is to provide a laser beam transmitting / receiving device capable of improving the S / N ratio by narrowing the beam diameter from the laser beam emission window to the laser beam emission window.

In order to solve the above-described problems, a laser transmitter / receiver according to the present invention collimates a semiconductor laser light source whose light emitting points are arranged in at least one row and a laser beam emitted from the semiconductor laser light source, A laser beam transmitting optical system that irradiates a predetermined optical member with a reduced diameter, an optical path of a transmitted light beam from the laser beam transmitting optical system to the predetermined optical member, and a return from the predetermined optical member An optical path separating member that separates the optical paths of the luminous flux from each other;
The laser light transmitting optical system includes, in order from the semiconductor laser light source side, a collimating lens portion having a positive power, a first cylindrical lens having a positive refractive power in a direction orthogonal to the bonding surface of the semiconductor laser light source, and the A beam expander portion including a second cylindrical lens having a refractive power in a direction orthogonal to the bonding surface of the semiconductor laser light source and a slit portion are arranged, and between the first cylindrical lens and the second cylindrical lens, or Between the second cylindrical lens and the slit portion, a third cylindrical lens having a positive refractive power in a direction parallel to the joint surface of the semiconductor laser light source is disposed,
The rear focal position of the collimating lens portion and the front focal position of the third cylindrical lens are arranged so as to substantially coincide with each other.

In the laser transmitter / receiver of the present invention, the light emitting point collimates the semiconductor laser light source arranged in at least one row and the laser light emitted from the semiconductor laser light source, and the light beam diameter is reduced. The optical system for transmitting laser light that irradiates the predetermined optical member with the optical path of the transmitted light beam from the optical system for transmitting laser light to the predetermined optical member and the optical path of the return light beam from the predetermined optical member are mutually connected. An optical path separating member for separating,
The laser light transmitting optical system includes, in order from the semiconductor laser light source side, a collimating lens portion having a positive power, a first cylindrical lens having a positive refractive power in a direction orthogonal to the bonding surface of the semiconductor laser light source, A beam expander portion made of a second cylindrical lens having a refractive power in a direction orthogonal to the joint surface of the semiconductor laser light source, and a slit portion for allowing the output light from the second cylindrical lens to pass through are arranged. It is a feature.

Further, the predetermined optical member is a scan mirror that reflects the laser light from the laser light transmission optical system so as to scan the space multi-dimensionally toward the predetermined space, and the object in the space The return light reflected from the laser beam and returned to the scan mirror, and reflected by the scan mirror so as to reverse the optical path of the laser beam,
It is possible to output the laser beam in a direction deviating from the optical path of the laser beam by the optical path separating member, receive the light by a light receiving element, and recognize the object based on information carried on the return light.

  Here, the refractive power of the second cylindrical lens may be positive or negative, and is combined with the first cylindrical lens to form a beam expander that reduces the beam diameter in a direction orthogonal to the joint surface. Anything is possible.

Further, the collimating lens portion and the first cylindrical lens can be integrally formed, and a single lens can be configured to have both functions fused. In this case, at least one surface of the lens can be provided. It is effective to make the shape a free-form surface that is rotationally asymmetric with respect to the optical axis.
In addition, a configuration in which the second cylindrical lens and the third cylindrical lens are integrated is possible, and in this case also, at least one surface shape of the lens is a free-form surface that is rotationally asymmetric with respect to the optical axis. It is valid.

  According to the laser beam transmission / reception device of the present invention, as a laser beam output lens system, a collimator lens unit having a positive power is sequentially aligned from the semiconductor laser light source side in a direction orthogonal to the bonding surface of the semiconductor laser light source. A beam expander portion comprising a first cylindrical lens having a refractive power and a second cylindrical lens having a refractive power in a direction orthogonal to the joint surface of the semiconductor laser light source, and a slit portion on the scan mirror side It is possible to output each laser beam as a thin parallel beam.

  Thus, for example, when mounted on an automatic monitoring device or the like, each laser beam can be made into a thin beam state up to the scan mirror, and the laser beam irradiated to the projection space by the scan mirror is not greatly diffused. Since the object is irradiated, noise can be reduced and the light intensity of the return light from the object can be increased.

  Also, a third cylindrical lens having a positive refractive power in a direction parallel to the bonding surface of the semiconductor laser light source is disposed between the first cylindrical lens and the second cylindrical lens, or between the second cylindrical lens and the slit portion. Then, in this direction, the rear focal position of the collimating lens portion and the front focal position of the third cylindrical lens are arranged so as to substantially coincide with each other, so that each light emitting point is parallel to the joint surface. Since the laser beams can be made substantially parallel to each other, the diffusion of each laser beam can be further suppressed, and the light intensity sufficient to detect the return light from the object can be obtained.

  Hereinafter, a laser beam transmitter / receiver according to an embodiment of the present invention will be described with reference to the accompanying drawings. Before describing the laser beam transmitter / receiver in detail, as an application example of the laser beam transmitter / receiver, an automatic monitoring device for identifying an arbitrary object equipped with the laser beam transmitter / receiver will be described. In each attached drawing, in order to make the explanation easy to understand, distances between components and individual sizes are appropriately changed and shown.

<Configuration of automatic monitoring device>
First, an automatic monitoring apparatus equipped with a laser beam transmitter / receiver according to an embodiment of the present invention will be briefly described with reference to FIG. FIG. 4 is a block diagram of an automatic monitoring device equipped with a laser beam transmitter / receiver according to an embodiment of the present invention.

The automatic monitoring device 1 shown in FIG. 4 is for monitoring whether or not an object is present in the space R, and a light source unit composed of semiconductor laser light sources in which light emitting points are arranged in at least one row. 3 and a laser beam sending lens unit 16 that collimates the laser beam emitted from the light source unit 3 and outputs the light beam with a reduced beam diameter, and the laser beam output from the laser beam sending lens unit 16 the light B ₁ with scanning radiation towards the space R, a laser light beam transmitting and receiving apparatus 10A for converging the laser beam reflected from the object M in the space R (return light) B ₂ on the light-receiving element 5 will be described later And a control unit 20 for performing various controls and arithmetic processes.

The laser light beam transmitting and receiving apparatus 10A, details but will be described later, the laser beam B ₁ from the laser beam delivery lens 16, the galvano mirror or the like (a semiconductor resonance mirror, for example, Nippon Signal ECO Co., Ltd. SCAN (registered (Trademark)) is irradiated toward the space R so as to scan the space R in a multidimensional manner, and the return light B ₂ from the object M is scanned with the scan mirror 11 The light receiving element 5 is configured to receive light through the reflection mirror 13 and the condenser lens 15.

The control unit 20 includes a pulse generation circuit 21 for converting the laser beam B ₁ emitted from the light source unit 3 into an optical pulse, an amplifier 22 for amplifying a signal output from the light receiving element 5, and a scan mirror. 11, the output timing of the laser beam B ₁ from the light source unit 3 based on the signal from the scan mirror control unit 23 for controlling the tilt angle of 11, the signal from the pulse generation circuit 21 and the signal from the amplifier 22, and the object M A time difference detection unit 24 that detects a time difference from the timing of reflection and reception by the light receiving element 5 is provided. The distance detection unit 25 calculates the distance to the object M based on the time difference information detected by the time difference detection unit 24, and the direction detection unit 26 determines the direction of the object M based on the signal from the scan mirror control unit 23. , And based on the detected distance information and direction information, the distance image generation unit 27 generates a distance image of the object M (an image indicating the distance, direction, and size), and further generates the generated object M. The object identification unit 28 is configured to identify whether or not the object M is a target object based on the distance image.

<Configuration of laser beam transmitter / receiver>
Next, the laser beam transmitter / receiver 10A will be described in more detail with reference to FIG. In FIG. 5, the method of showing the constituent members is different from that in FIG. 4, and in FIG. 4, some members not shown are shown.

As shown in FIG. 5, the laser beam transmitting / receiving device 10A includes a laser beam transmitting optical system including a laser beam transmitting lens portion 16 (details will be described later) and a slit plate 17 (details will be described later), and the above-described perforated holes. A reflection mirror 13, a scan mirror 11, and a condenser lens 15 are provided. The central portion of the perforated reflecting mirror 13, the reflecting surface 13b is formed with a hole 13a penetrating to the back surface 13c, the laser beam B ₁ emitted from the light source unit 3, passes through the the hole 13a Thus, the scan mirror 11 is irradiated.

Scan mirror 11, the laser beam B ₁ from the light source unit 3, dissipate reflected toward the spatial R to scan the space R multidimensionally, in the object M (Fig. 5 in the space R, The return light B ₂ from (not shown) is reflected so as to travel backward in the optical path of the laser light B ₁ . The return light B ₂ that reversing the optical path of the laser beam B ₁ represents, beam diameter than that of the laser beam B ₁ from the light source unit 3 has become large, the perforated reflecting mirror 13, the reflection of the periphery of the hole portion 13a in the surface 13b, it is reflected in a direction deviating from the optical path of the laser beam B _1, further adapted to be received by the light receiving element 5 is condensed by the condenser lens 15.

As described above, the laser beam transmitter / receiver 10 </ b> A includes an optical path until the laser beam B ₁ emitted from the light source unit 3 is irradiated from the light source unit 3 through the scan mirror 11 into the space R, and an object in the space R. the return light B ₂ from M are coaxial system type and the optical path overlap each other halfway up to the light receiving element 5 from the object. For this reason, it is not necessary to use a wide-angle, high-efficiency, expensive condenser lens, which is necessary for the non-coaxial type. In addition, since the conceivable angle of the condenser lens or the like is narrow and it becomes difficult for extra background light to enter the light receiving element, the S / N ratio improves.

A perforated reflection mirror 13 is used as an optical path separating member that separates the optical path of the return light B ₂ from the optical path of the laser light B ₁ from the light source unit 3. Laser light B ₁ emitted from the light source unit 3, so passing through the hole portion 13a of the perforated reflecting mirror 13, a problem that occurs when using a half mirror as the optical path separating member as in the prior art, i.e., the light source When the laser beam B ₁ from the unit 3 passes through the half mirror, scattered light is generated at the interface of the half mirror, and the problem that the scattered light enters the light receiving element 5 through the condenser lens 15 is prevented in advance. can do. This also makes it possible to improve the S / N ratio.

Further, in the laser beam transmitting / receiving device 10A, as described above, between the light source unit 3 and the perforated reflection mirror 13, the laser beam transmitting lens unit 16 and one or a plurality (two in FIG. 5). ) Slit plate 17 is provided. The central portion of the slit plate 17, a smaller width than the hole 13a formed in the perforated reflecting mirror 13, a slit 17a is formed, the laser beam B ₁ emitted from the light source unit 3, the laser After passing through the light output lens portion 16, the light passes through the slit 17 a and then passes through the hole portion 13 a of the perforated reflection mirror 13. By arranging such a slit plate 17, the laser beam B ₁ of the light flux diameter of the light source unit 3, it becomes possible to narrow sufficiently smaller than the diameter of the hole 13a of the perforated reflecting mirror 13, laser beam B ₁ from the light source 3 is irradiated to the end of the hole 13a of the perforated reflecting mirror 13 scattered light can be prevented from being generated.

Further, the hole 13a of the perforated reflection mirror 13 is formed so as to expand in a tapered shape from the reflection surface 13b toward the back surface 13c. Therefore, any chance, even if the scattered light laser beam B ₁ from the light source 3 is irradiated to the end of the hole 13a of the perforated reflecting mirror 13 is generated, that the scattered light is directed toward the light receiving element 5 Can be prevented.

In the laser beam transmitter / receiver 10A, the scan mirror 11 is reflected between the scan mirror 11 and the space R from the laser beam B ₁ going from the scan mirror 11 into the space R and the object M in the space R. a transparent cover 19 that transmits are disposed return light B ₂ towards.

Further, in the laser light beam transmitting and receiving apparatus 10A, after the laser beam B ₁ from the light source section 3 passes through the lumen 13a of the perforated reflecting mirror 13, when incident on the scan mirror 11, the scanning mirror 11 Even when scattered light is generated on the reflecting surface, the scattered light returns to the incident direction and is prevented from entering the light receiving element 5 reflected by the reflecting surface 13b of the perforated reflecting mirror 13.

<Laser light transmission optical system>
Hereinafter, a laser light transmission optical system including the laser light transmission lens portion 16 and the slit plate 17 will be described with reference to FIGS. In FIG. 1, (A) is a side view showing an optical system for laser beam transmission, and (B) is a plan view thereof.

  As shown in FIGS. 1A and 1B, the laser beam sending lens unit 16 collimates the laser beam emitted from the light source unit 3 and irradiates the scan mirror 11 with the beam diameter reduced. The first cylindrical lens having a positive refractive power in a direction orthogonal to the joint surface of the semiconductor laser light source constituting the light source unit 3 in order from the light source unit 3 side. 53, a second cylindrical lens 54 having a negative refractive power in a direction orthogonal to the joint surface, and a third cylindrical lens 55 having a positive refractive power in a direction parallel to the joint surface.

  The first cylindrical lens 53 and the second cylindrical lens 54 constitute a beam expander portion as shown in FIG. 1A, and the collimating lens portion 52 is within a plane orthogonal to the joint surface. The light beam diameter of the parallel light beam from is reduced and output.

  In the laser beam transmitter / receiver 10A of the present embodiment, a laser light source having an array structure in which single stripe semiconductor lasers are arranged in a row as the light source unit 3 (hereinafter referred to as a columnar array laser light source) is used. The size of the light emitting surface is, for example, approximately 1 μm × 150 μm and a line shape. As a result, the laser output can be, for example, about ten times the output of the single stripe semiconductor laser (for example, about several tens of watts), and the laser beam can be satisfactorily irradiated to a distant object.

  However, since the cross-sectional shape of the output light from such a light source unit 3 is a line shape according to the shape of the light emitting surface, the major axis direction (direction parallel to the bonding surface) of the light emitting surface is short. Since the beam divergence angle (full angle) in the radial direction (the direction perpendicular to the joint surface) differs greatly from about 10 degrees in the former and about 30 degrees in the latter, simple lenses such as multiple spherical lenses and aspherical single lenses When the configuration is used, the laser light is diffused particularly in a state in which a distant object is irradiated, and even if the light source unit 3 has a high output, the return light from the detection object becomes weak.

  Therefore, in the laser beam sending lens unit 16 of the present embodiment, the major axis direction and the minor axis direction have different refracting powers corresponding to the shape of the light emitting surface. Then, the scan mirror 11 is configured to irradiate the laser beam which is not diffused.

  That is, each laser beam emitted from the light source unit 3 is converted into a parallel light state by the collimating lens unit 52 in both the major axis direction and the minor axis direction of the light emitting surface. However, as described above, due to the difference in beam divergence angle, the beam is formed in a wide beam shape in the minor axis direction of the light emitting surface (direction perpendicular to the bonding surface) (see FIGS. 1A and 1B). Therefore, as shown in FIG. 1 (A), a beam expander portion composed of two cylindrical lenses 53 and 54 having refractive power only in the minor axis direction of the light emitting surface (direction orthogonal to the bonding surface) is used. The beam is shaped into a narrow beam shape in the minor axis direction of the light emitting surface.

  In the laser beam sending lens unit 16 of the present embodiment, the rear focal position of the collimating lens unit 52 and the front side of the third cylindrical lens 55 in the major axis direction of the light emitting surface (the direction parallel to the cemented surface). The focal positions are arranged so as to substantially coincide with each other, whereby each laser beam 60 output from the third cylindrical lens 55 can be output substantially parallel to the optical axis z as shown in FIG. I can do it. Further, each laser beam 60 is configured to be narrowest at the position of the slit plate 17 in the major axis direction of the light emitting surface (direction parallel to the bonding surface).

Thus, in the laser beam sending lens unit 16 of the present embodiment device, each laser beam 60 is in a thin beam state while using output light from a high-power semiconductor laser whose cross-sectional shape is a line shape. Further, the light can be guided to the transparent cover 19 through the scan mirror 11 without being diffused.
Further, as shown in FIG. 1B, the slit plate 17 is formed of a light shielding plate having a slit 17a (see FIG. 5) having a long shape in the major axis direction (direction parallel to the bonding surface) of the light emitting surface. It is for cutting light.

  FIG. 7 ((A) is a side view and (B) is a plan view) shows a laser beam sending optical system of a device according to the prior art, and is composed of a columnar array laser light source similar to the above embodiment. A collimating lens unit 152 for collimating the laser beam 160 output from the light source unit 103 is provided, and the laser beam 160 is collimated to irradiate a scan mirror (not shown). According to this prior art, although both the major axis direction and the minor axis direction of the light emitting surface are in the state of parallel light, the laser beam 160 when irradiated to the scan mirror is shown in FIGS. Compared with the present embodiment shown in B), the beam diameter is wider in any of the above directions, and the laser beams 160 are greatly diffused in the major axis direction of the light emitting surface. It has become.

In other words, in the laser beam sending lens unit 16 of the apparatus according to the present embodiment, each laser beam is in a narrow beam state and is not diffused as compared with the conventional one, and the scan mirror 11 (and the transparent cover 19). ) Can be irradiated.
As a result, the laser beam 60 applied to the space R by the scan mirror 11 can reduce noise and, as shown in FIG. 2, is applied to the object 70a without being greatly diffused. The return light from the object 70a can have a sufficient light intensity for detection and have a high S / N ratio.

  Further, the laser light transmission optical system of the laser light transmission / reception device of the present invention is not limited to the above-described embodiment. For example, the second cylindrical lens 54 is combined with the first cylindrical lens 53, Any beam expander that reduces the beam diameter of the laser beam may be used. By adjusting the position of the second cylindrical lens 54 in the direction of the optical axis, the second cylindrical lens 54 is changed to a positive lens. Instead, it can be constituted by a negative lens.

  In addition, the third cylindrical lens 55 can be omitted as a laser beam sending optical system of the laser beam sending / receiving device of the present invention. The laser beam sending lens portion 86 in this case is shown in FIGS.

  3A and 3B, the laser beam sending lens unit 86 of the laser beam sending optical system is a collimating lens unit having a positive power in order from the light source unit 3 side including a columnar array laser light source. 82, a first cylindrical lens 83 having a positive refractive power in a direction orthogonal to the bonding surface of the semiconductor laser light source constituting the light source unit 3, and a second cylindrical lens having a negative refractive power in the direction orthogonal to the bonding surface. The lens 84 is arranged. The first cylindrical lens 83 and the second cylindrical lens 84 constitute a beam expander unit as shown in FIG. 3, and the light beam diameter of the parallel light beam from the collimating lens unit 82 is set to the light emitting surface of the light source unit 3. The output is reduced in the minor axis direction. Further, a slit plate 17 is provided at the subsequent stage of the laser beam sending lens portion 86. 3A and 3B, the laser beam sending optical system shown in FIGS. 3A and 3B has a laser beam emitting system in the major axis direction of the light emitting surface as compared with the laser beam sending optical system shown in FIGS. Are not suppressed, but parallel light is emitted in both the major axis direction and the minor axis direction of the light emitting surface in the same manner as the laser beam sending optical system shown in FIGS. 1 (A) and 1 (B). In particular, the beam diameter is narrow in the minor axis direction. Thereby, noise can be reduced, and the light intensity of the return light from the object 70a can be secured to some extent.

<Modification>
Note that the laser beam transmitting / receiving device according to the present invention is not limited to the one shown in FIG. 5, and may be configured as shown in FIG. 6, for example. Hereinafter, the laser beam transmitter / receiver according to the embodiment shown in FIG. 6 will be described.
In FIG. 6, the same members as those used in FIG. 5 are assigned to the same members as those constituting the above-described laser light transmitting / receiving device 10 </ b> A.

A laser beam transmitter / receiver 10B illustrated in FIG. 6 includes a laser beam transmitting lens unit 16, a slit plate 17, a minute reflection mirror 14, a scan mirror 11, and a condenser lens 15. Micro reflecting mirror 14, the central portion of the light transmitting surface 14b for transmitting light, reflecting light, is configured to bore has a small reflecting surface 14a, the laser beam B ₁ emitted from the light source unit 3, the The scan mirror 11 is irradiated with the light reflected by the reflecting surface 14a.

Scan mirror 11, the laser beam B ₁ from the reflecting surface 14a of the micro reflecting mirror 14, the reflecting towards the space R to scan the space R multidimensionally, the object M in the space R ( In FIG. 6, the return light B ₂ from (not shown) is reflected so as to travel backward in the optical path of the laser light B ₁ . The return light B ₂ that reversing the optical path of the laser beam B ₁ represents, beam diameter than that of the laser beam B ₁ from the light source unit 3 has become large, the micro reflecting mirror 14, the periphery of the reflecting surface 14a transmitted through the light transmitting surface 14b, and traveling in a direction out of the optical path of the laser beam B _1, further adapted to be received by the light receiving element 5 is condensed by the condenser lens 15.

Thus, the laser light beam transmitting and receiving device 10B includes the optical path to the laser light B ₁ emitted from the light source unit 3 is radiated into the space R via the scanning mirror 11 from the light source unit 3, the object in the space R the return light B ₂ from the M is coaxial system type and the optical path overlap each other halfway up to the light receiving element 5 from the object, the same effect as the laser beam transmitting and receiving optical device 10A described above.

Further, as the optical path separating member that separates the optical path of the return light B ₂ from the optical path of the laser light B ₁ from the light source unit 3, the minute reflection mirror 14 is used. Laser light B ₁ emitted from the light source unit 3, in the micro reflection surface 14a of the micro reflecting mirror 14, if so is reflected in a direction deviating from the direction of the light receiving element 5, the scattered light at the reflection surface 14a is generated However, it is possible to prevent the scattered light from entering the light receiving element 5 through the condenser lens 15. Thereby, it is possible to improve the S / N ratio.

Further, as described above, between the light source unit 3 and the minute reflection mirror 14, the laser beam sending lens unit 16 as described in the above embodiment and one or a plurality of (two in FIG. 6) slits. A plate 17 is provided. The central portion of the slit plate 17, the reflecting surface width smaller slit 17a than the diameter of 14a is formed, the laser beam B ₁ emitted from the light source unit 3 of the micro reflecting mirror 14, laser beam delivery After passing through the lens portion 16, it passes through the slit 17 a and reaches the reflection surface 14 a of the minute reflection mirror 14. By providing such a slit plate 17, the beam diameter of the laser beam B ₁ from the light source unit 3 can be reduced to be sufficiently smaller than the aperture of the reflecting surface 14 a of the minute reflecting mirror 14. It is possible to prevent the scattered light from being emitted by irradiating the end portion of the reflection surface 14 a of the micro-reflecting mirror 14 with the laser beam B ₁ from the unit 3, and to prevent the scattered light from moving toward the light receiving element 5.

As mentioned above, although embodiment of this invention was described, this invention is not restricted to the thing of the said embodiment, The change of another various aspect is possible.
For example, in the above embodiment, a semiconductor laser light source having a plurality of light emitting points arranged in a row is used. However, if the light emitting surface is formed in a line shape, the light emitting points are arranged in two rows. Alternatively, it may be a plurality of rows such as 3 rows.

The laser beam transmitter / receiver of the present invention is not limited to the above-described automatic monitoring device, and is required to output a laser beam emitted from a columnar array laser light source in a narrowed state, and the laser beam irradiated object It is possible to mount on various devices that use the return light from as a detection light.
In addition, in Japanese Patent Laid-Open No. 10-332816, a transmission relay optical system is disclosed as in the present invention, but this transmission relay optical system prevents vignetting at the end face of the optical fiber, The object is to control the numerical aperture of the imaging lens arranged in front of the fiber end face. Therefore, the object and configuration of the present invention are greatly different.

Schematic showing a laser beam sending optical system of a laser beam sending and receiving device according to an embodiment of the present invention. Schematic showing the laser beam irradiated into the room space using the laser beam sending optical system shown in FIG. Schematic showing a laser beam sending optical system different from the laser beam sending optical system shown in FIG. Configuration diagram of an automatic monitoring device equipped with a laser beam transmitter / receiver according to an embodiment of the present invention The block diagram which shows the laser beam transmitter / receiver which concerns on embodiment of this invention The block diagram which shows the laser beam transmitter-receiver which concerns on embodiment different from the laser beam transmitter-receiver shown in FIG. Schematic showing a laser beam transmission optical system of a conventional laser beam transmitter / receiver

Explanation of symbols

1 Automatic monitoring device 3, 103 Light source (row array laser light source)
5 Light Receiving Element 11 Scan Mirror 13 Perforated Reflection Mirror 14 Micro Reflection Mirror 15 Condensing Lenses 16 and 86 Optical System 17 for Transmitting Laser Light Slit Plate 17a Slit 20 Control Units 52, 82 and 152 Collimating Lens Units 53 and 83 First Cylindrical Lenses 54, 84 Second cylindrical lens 55 Third cylindrical lenses 60, 90, 160 Laser light

Claims (3)

A semiconductor laser light source having a light emitting point arranged in at least one row and a laser beam that collimates the laser beam emitted from the semiconductor laser light source and irradiates a predetermined optical member with a reduced beam diameter And an optical path separating member that separates an optical path of a light beam transmitted from the laser light transmitting optical system to the predetermined optical member and an optical path of a return light beam from the predetermined optical member,
The laser light transmitting optical system includes, in order from the semiconductor laser light source side, a collimating lens portion having a positive power, a first cylindrical lens having a positive refractive power in a direction orthogonal to the bonding surface of the semiconductor laser light source, A beam expander portion composed of a second cylindrical lens having a refractive power in a direction orthogonal to the bonding surface of the semiconductor laser light source, and a slit portion are arranged, and between the first cylindrical lens and the second cylindrical lens, Alternatively, a third cylindrical lens having a positive refractive power in a direction parallel to the bonding surface of the semiconductor laser light source is disposed between the second cylindrical lens and the slit portion.
2. A laser beam transmitting / receiving device, wherein the rear focal position of the collimating lens portion and the front focal position of the third cylindrical lens are substantially matched. A semiconductor laser light source having a light emitting point arranged in at least one row and a laser beam that collimates the laser beam emitted from the semiconductor laser light source and irradiates a predetermined optical member with a reduced beam diameter And an optical path separating member that separates an optical path of a light beam transmitted from the laser light transmitting optical system to the predetermined optical member and an optical path of a return light beam from the predetermined optical member,
The laser light transmitting optical system includes, in order from the semiconductor laser light source side, a collimating lens portion having a positive power, a first cylindrical lens having a positive refractive power in a direction orthogonal to the bonding surface of the semiconductor laser light source, A beam expander portion made of a second cylindrical lens having a refractive power in a direction orthogonal to the joint surface of the semiconductor laser light source, and a slit portion for allowing the output light from the second cylindrical lens to pass through are arranged. A laser light transmitting / receiving device characterized.   The predetermined optical member is a scan mirror that reflects the laser light from the laser light transmitting optical system toward a predetermined space so as to scan the space in a multidimensional manner, and reflects the object from the space. Returning to the scan mirror, the return light reflected by the scan mirror so as to reversely travel the optical path of the laser light is output by the optical path separating member in a direction deviating from the optical path of the laser light. 3. The laser beam transmitter / receiver according to claim 1, wherein the laser beam is received by an element and is configured to recognize the object based on information carried on the return light.

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