JP3853204B2 - Laser beam scanning actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser beam scanning actuator.
[0002]
[Prior art]
As scanning devices using laser light, scanning laser radar devices, laser scanners, laser printers, laser markers, object monitoring devices, and the like are known. Among them, for example, a laser beam scanning actuator used in a scanning laser radar device for preventing collision of a vehicle is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-92270. In the actuator, a mirror disposed between a light transmitting element and a light receiving element is driven by a motor and a cam.
[0003]
[Problems to be solved by the invention]
In the laser beam scanning actuator as described above, the laser beam is surely scanned in the horizontal and vertical directions, and each component of the actuator does not exist on the emission optical axis of, for example, a semiconductor laser as a laser beam emitting element. It is desirable to do so. In order to scan the laser beam, the lens is moved in a direction transverse to the optical axis. Therefore, it is necessary to dispose the lens support frame, the driving device, and the like at a position away from the semiconductor laser and the optical axis.
[0004]
However, if the actuators are simply separated from each other, the size of the actuator will increase. When used as an in-vehicle radar, not only will the layout deteriorate due to interference with other components, but also the assembly, drive characteristics, and disturbance resistance characteristics.・ A problem arises in that drive efficiency also deteriorates.
[0005]
[Means for Solving the Problems]
In order to solve such problems and avoid the interference with other devices as much as possible to improve the layout, the present invention has been made in order to improve assembly, driving characteristics, disturbance resistance characteristics, and driving efficiency. In this case, a lens for passing the laser light emitted from the emitting means, a lens holder for holding the lens, a fixed base fixed to an attachment target, and a fixed base in the state in which the lens holder is fixed The cantilever support means provided between the fixed base and the lens holder so as to be cantilevered by the fixed base so as to be displaceable in the vertical and horizontal directions when the optical axis of the lens is the front-rear direction. And a driving means for driving the lens holder in the vertical and horizontal directions, the lens holder holding the lens, and the lens holding Connected to the cantilever support means, and the fixed base, the cantilever support means, the drive means, and the connection part of the lens holder are connected to the optical axis. It is arranged on the same side , and the connecting portion of the lens holder is offset toward the fixed base with respect to the lens holding portion in the optical axis direction, and the offset connecting portion is A part of driving means is provided .
[0006]
According to this, since the fixed base, the cantilever support means, the drive means, and the connecting portion of the lens holder are located on the side of the optical axis, there are no other components on the optical axis and the optical base is located on the optical axis. Assembling direction of the semiconductor laser, for example, as the emitting means can be set arbitrarily, no parts are required to define the assembling direction, and the number of parts can be reduced, so that assembling is improved and cost reduction is promoted. Can do. Further, since the drive circuit portion (drive means and the like) is collected by opening the optical axis of the lens, space efficiency can be improved and downsizing can be promoted.
[0007]
Further, the cantilever support means includes four lateral displacement springs each having one end coupled to the lens holder at four locations on the upper, lower, left and right sides, and each other end of the lateral displacement spring. A movable support unit coupled to the movable support unit, and four vertical displacement springs provided so as to connect the base to the movable support unit in four directions, up and down, left and right; The yoke includes a yoke fixed to the base and a magnetic coil provided on the movable side, and at least one of the four horizontal displacement springs and the four vertical displacement springs. Since the magnetic coil is disposed in one of the spans, the support in the vertical and horizontal directions is independent, so that the support rigidity in the rotational direction around the longitudinal axis is improved, and each leaf spring is The By the down widely took place, it can be further increased rotation supporting rigidity. Furthermore, by forming each leaf spring with a conductive spring material, each leaf spring can be used as a lead wire to each coil, and the number of parts can be reduced.
[0008]
Further, according to the 請 Motomeko 3, since the vertical and horizontal directions are respectively restricted with respect to the other direction, it is possible to increase the rotation direction support stiffness relative to the axis about the longitudinal axis.
[0009]
Further, by the arrangement took wide span of the plate spring, it can be further increased rotation supporting rigidity. Furthermore, by forming each leaf spring with a conductive spring material, each leaf spring can be used as a lead wire to each coil, and the number of parts can be reduced.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on specific examples shown in the accompanying drawings.
[0011]
FIG. 1 is a perspective view showing a laser beam scanning actuator used in a scanning laser radar apparatus for vehicle collision prevention to which the present invention is applied. 2 is a top view showing the laser beam scanning actuator, FIG. 3 is a side view seen from the arrow III line of FIG. 2, and FIG. 4 is an exploded perspective view of the main part. In the illustrated laser beam scanning actuator, the front / rear, up / down, and left / right directions are indicated by arrows in FIG. 1, and the front / rear direction is aligned with the front / rear direction of the vehicle in the state of being attached to the vehicle. This will be described below.
[0012]
This laser beam scanning actuator is supported via a fixed base 1 fixed to a vehicle body (frame) (not shown) and four vertical displacement leaf springs 2 extending from the fixed base 1 as cantilever support means. The coil support body 3 has a rectangular frame shape as the movable support portion, and the lens holder 5 is supported by the coil support body 3 via four lateral displacement springs 4. In the lens holder 5, the scanning lens 7 for passing the light emitted from the laser diode 6 as the emitting means and the light receiving photodiode 8 for receiving the reflected light reflected and returned by an obstacle or the like are condensed. For this purpose, a light receiving lens 9 is integrally provided.
[0013]
The four plate springs 2 for upward / downward displacement are fixed at one end on both upper and lower surfaces of a standing wall portion extending in the vertical direction of the base 1 with each main surface facing the vertical direction in the figure, and on the rear side So as to extend parallel to each other. The other end portions of the vertical displacement leaf springs 2 are coupled to appropriate positions on the coil support 3 in the vertical and horizontal directions. As a result, since the vertical displacement plate spring 2 can be bent only in the vertical direction in the figure, the coil support 3 is supported so as to be movable in the vertical direction with respect to the base 1.
[0014]
The base 1 and the coil support 3 may be made of synthetic resin. In the illustrated example, a pair of holes are provided at both ends in the longitudinal direction of the vertical displacement leaf spring 2, and the base 1 and the coil to be coupled are provided. Projecting bosses are formed in corresponding portions of the support 3. Then, a hole provided in the leaf spring is fitted to the protruding boss portion, the plate-like pressing member 10 is overlapped with the leaf spring, and a coupling hole provided in the holding member 10 is fitted to the protruding boss portion to It is fixed so that the end of is pressed against the object to be joined. In this way, it can be easily assembled. In addition, each of these components can be integrated by insert molding of a leaf spring, and in that case, it is possible to perform assembly more easily and with higher positional accuracy.
[0015]
Further, the four leaf springs 4 for lateral displacement are fixed to the left and right frame portions in the drawing of the coil support 3 with their respective main surfaces facing the left and right directions in the drawing, and to the front side. It is arranged to extend beyond the base 1 in parallel. The end portions of the left and right displacement leaf springs 4 are coupled to appropriate positions of the lens holder 5. As a result, the left-right displacement plate spring 4 can bend only in the left-right direction in the figure, so that the lens holder 5 is supported so as to be displaceable in the left-right direction with respect to the base 1. The fixing of the lateral displacement plate spring 4 to the object to be coupled (coil support 3 and lens holder 5) is the same as described above. In addition, although each holding member 10 has a difference in shape, the same code | symbol is attached | subjected.
[0016]
According to this layout, the lens holder 5 is supported so as to be displaceable in the vertical and horizontal directions via the leaf springs 2 and 4 with respect to the base 1. Then, a vertical displacement leaf spring 2 extends rearward from the base 1, and the left and right displacement leaf spring 4 crosses the base 1 from the coil support 3 coupled to the vertical displacement leaf spring 2 to the front side. Therefore, the horizontal displacement plate spring 4 is longer than the vertical displacement plate spring 2. In other words, each displacement allowance of the lens holder 5 (lenses 7 and 9) in the vertical and horizontal directions can be increased in the horizontal direction. This is because in-vehicle radar scans larger in the horizontal direction than in the vertical direction in order to detect an obstacle in the traveling direction.
[0017]
The lens holder 5 includes a connecting portion 5a to which the end portions of the lateral displacement plate spring 4 are coupled, and a lens holding portion 5b for holding the lenses 7 and 9, and the connecting portion 5a and For example, the lens holding portion 5b is integrally formed of a synthetic resin material so as to be arranged in parallel in the left-right direction of the drawing. Each of the lenses 7 and 9 is a full-length lens that is lightweight and suitable for downsizing in the illustrated example, but is not limited thereto.
[0018]
Next, the structure of the driving means for driving the lens holder 5 in the vertical and horizontal directions will be described. A vertical driving coil 11 wound in an oval shape with its long axis directed in the left-right direction is integrally fixed to the coil support frame 3. As shown in FIG. 5, the yoke 12 that forms a magnetic circuit in cooperation with the vertical drive coil 11 stands upright of the base 1 so as to surround the vertical drive coil 11 about its major axis. It is fixed on the rear surface of the building wall. The coupling between the yoke 12 and the base 1 may be due to the fitting of irregularities. A pair of magnets 13a and 13b whose magnetic poles are vertically changed are fixed to one of the inner surfaces of the yoke 12 facing each other with the vertical drive coil 11 therebetween (in the illustrated example, the base 1 side).
[0019]
Further, as shown in FIG. 6, the connecting portion 5 a of the lens holder 5 is provided with two support frames 5 c extending in the vertical direction inside the left and right displacement plate springs 4 in the horizontal direction. The left and right drive coils 14 wound in an oval shape having a long axis in the vertical direction are provided between the support frames 5c. The yoke that forms the magnetic circuit in cooperation with the left and right drive coils 14 is configured such that a pair of U-shaped yokes 15 are arranged in parallel with each other in parallel with each other in a symmetrical form with the coil axis of the left and right drive coils 14 as the axis of symmetry. It is provided with a gap. Each of the coils 11 and 14 may be insert-molded in the same manner as in the other examples of the leaf springs described above, and can be assembled simply and with high positional accuracy as in the case of the leaf springs. In addition, if both the leaf spring and the coil are insert-molded, the effect can be further enhanced.
[0020]
The open end surfaces of both U-shaped yokes 15 are joined to L-shaped extending portions 12a formed integrally with the yoke 12, and the open end surfaces of both U-shaped yokes 15 are closed by the extending portions 12a. And is integrally supported by the yoke 12 via the extending portion 12a. Further, the same magnetic pole is applied to one of the inner surfaces of the U-shaped yokes 15 across the left and right drive coils 14 (outside of the left and right drive coils 14 in the illustrated example) with respect to the left and right drive coils 14. Oriented magnets 16a and 16b are respectively fixed.
[0021]
In the illustrated example, as shown in FIG. 7, the coils 11, 14 and an external drive circuit (not shown) are connected via the leaf springs 2, 4. For this purpose, the plate springs 2 and 4 are formed of a conductive spring material, and each of the plate springs 2 and 4 has a pair of terminal portions 2a and 4a at both longitudinal ends as well shown in FIG. Is provided. The terminal portions 2a and 4a are exposed in a state where the leaf springs 2 and 4 are coupled to the base 1, the coil support frame 3, and the lens holder 5, respectively.
[0022]
For example, the terminal portions 2a on the base 1 side of the four vertical displacement leaf springs 2 are connected to the output terminals of the external drive circuit via lead wires. Both ends of the coil wire of the upper and lower drive coil 11 are connected to each terminal portion 2a on the side opposite to the two bases 1 side of the four leaf springs 2. Further, each of the terminal portions 2a on the side opposite to the other two bases 1 side of the four leaf springs 2 and two corresponding sides (coils) of the four lateral displacement leaf springs 4 Each terminal portion 4a on the support 3 side) is connected via a lead wire. Then, both ends of the coil wire of the left and right driving coil 13 are connected to each terminal portion 4a on the side opposite to the coil support 3 side of the two leaf springs 4.
[0023]
In this way, by using the leaf springs 2 and 4 for electrical connection to the coils 11 and 13, the coil lead wire can be directly soldered to the leaf spring (terminal portion), so that the terminal block is separately provided. There is no need to provide it, and the number of parts can be reduced. When a lead wire is directly connected to a coil (or a coil wire is pulled out), even if the lead wire is lengthened to give a margin, the lead wire will swing with respect to the coil movement. There is a possibility that the lead wire becomes a resistance to the movement of the movement and hinders the responsiveness. On the other hand, according to the present invention, since the portion connected to the coil 11 of the leaf spring 2 and the coil 11 are displaced together with the coil support 3, there is no displacement difference between both ends of the lead wire, The lead wire does not become a resistance against the movement of the coil. The same is true between the leaf spring 4 and the coil 13.
[0024]
The drive means is configured in this way, and by changing the direction of the current flowing through the vertical drive coil 11, the coil support 3 is moved vertically with respect to the base 1 as shown by the arrow A in FIG. Can be displaced. Similarly, the lens holder 5 can be displaced in the left-right direction as shown by the arrow B in FIG. 6 with respect to the coil support 3, that is, the base 1, by changing the direction of the current passed through the left-right drive coil 14. .
[0025]
In the lens holder 5 according to the present invention, the lens holding portion 5b is provided on the side of the connecting portion 5a with the leaf spring 4. Therefore, as shown in FIG. 2, the rear side of the lens holding portion 5b (on the laser diode 6 / photodiode 8 side) on the optical axis of the lenses 7 and 9 is opened. Therefore, the mounting direction of the laser diode 6 and the photodiode 8 arranged on the optical axis C can be made arbitrary. Furthermore, since the magnetic circuit section is concentrated on the side of the optical axis C, the entire apparatus becomes compact.
[0026]
The cantilever support means in the illustrated example has a structure in which the plate springs 2 and 4 are connected between the fixed base 1 and the lens holder 5 via the coil support 3. Using a spring, the lens holder 5 can be directly cantilevered by the fixed base 1 via a wire spring. Even in this case, the above-described layout can be achieved.
[0027]
In addition, the horizontal (horizontal) direction and the vertical (vertical) direction are controlled by the above-described structure of the leaf springs 2 and 4 so that the vertical and horizontal directions are restricted with respect to other directions. Directional support rigidity can be increased. Furthermore, since each leaf spring 2 and 4 has a four-part divided structure, the rotational support rigidity can be further increased by arranging each one of the spans widely.
[0028]
Further, as described above, the lens holder 5 supports the coil (the left and right driving coil 14) for the direction (left and right direction in the illustrated example) in which the displacement amount of the lenses 7 and 9 in the use state is large. Since the left and right driving coil 14 is displaced not only in the left and right direction but also in the up and down direction, the number of windings is increased so that a sufficient driving force can be obtained even in the displaced position when displaced in the up and down direction. . However, since the amount of vertical displacement is small, the number of extra windings is reduced. As a result, a necessary driving force can be ensured without requiring an extra number of windings.
[0029]
In addition, a driving point (a magnetic circuit that drives in the vertical and horizontal directions) is disposed between the leaf springs 2 and 4, which can reduce the rotational moment caused by variations and the like, which affects the driving characteristics. Can be prevented.
[0030]
Further, as shown in FIG. 2, the connecting portion 5a of the lens holder 5 is offset so that the connecting portion 5a of the lens holder 5 is offset to the rear side in the optical axis C direction (close to the base 1) with respect to the lens holding portion 5b. The lens holding portion 5b is bent. As a result, the left and right driving coils 14 are positioned rearward with respect to the mounting surfaces (lens holding portion 5b) of the lenses 7 and 9, and are forward of the lens surface (the side opposite to the fixed base 1 side). Therefore, it is possible to secure an optical path for the lenses 7 and 9 to transmit and receive light and to set the center of gravity of the movable portion (mainly the left and right driving coil 14) at the spring end. It is possible to reduce the generation of unstable moments when a disturbance is input.
[0031]
In the scanning laser radar device for preventing the collision of the vehicle in the illustrated example, the frequency due to the disturbance of the vehicle is relatively low (for example, about 10 Hz), so as not to resonate with such a low frequency. It is preferable to increase the resonance frequency, and the resonance frequency can be increased by the layout in which the center of gravity of the movable part is positioned at the spring end as described above. Therefore, it is preferable to apply the actuator according to the present invention for vehicle use.
[0032]
【The invention's effect】
Thus, according to the present invention, since the fixed base, the cantilever support means, the drive means, and the connecting portion of the lens holder are located on the side of the optical axis, there are no other parts on the optical axis, and the optical axis Assembling direction of, for example, a semiconductor laser as the emitting means arranged on the top can be made arbitrary, and parts for defining the assembling direction are not required, and the number of parts can be reduced. Costing can be promoted. In addition, the optical axis of the lens is opened, and as a result, the driving circuit unit (driving means, etc.) is integrated, so that space efficiency can be improved and miniaturization can be promoted.
[0033]
In addition, since the lens holder connecting portion is offset toward the fixed base in the optical axis direction, there is no component in front of the lens surface (the side opposite to the fixed base), so the lens projects and receives light. The center of gravity of the movable part assembled to the lens holder can be positioned at the spring end, and an unnecessary moment is hardly generated at the time of disturbance input, and the characteristics are stabilized.
[0034]
In addition, by attaching a magnetic coil that drives the lens in a direction that greatly displaces the lens holder, the magnetic coil attached to the lens holder has a small amount of displacement by the other magnetic coil and a large driving force. Therefore, it is possible to prevent an increase in weight and to secure a sufficient driving force.
[0035]
In addition, by using four leaf springs each for cantilever support means for vertical displacement and lateral displacement, the vertical and horizontal support is independent, so that rotation about the longitudinal axis is possible. The support rigidity in the direction is improved, and the rotation support rigidity can be further increased by arranging the leaf springs to have a wide span. Further, by forming each leaf spring with a conductive spring material, each leaf spring can be used as a lead wire to each coil, and the number of parts can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a laser beam scanning actuator to which the present invention is applied.
2 is a top view of the laser beam scanning actuator of FIG. 1. FIG.
FIG. 3 is a side view taken along the line III of FIG.
4 is an exploded perspective view of the main part of the laser beam scanning actuator of FIG. 1. FIG.
FIG. 6 is a fragmentary plan view showing a main part of a left-right direction driving magnetic circuit.
FIG. 7 is a perspective view showing an electrical connection state between a leaf spring and a coil.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed base 2 Vertical displacement plate spring 3 Coil support body 4 Horizontal displacement plate spring 5 Lens holder 6 Laser diode 7 Scanning lens 8 Light reception photodiode 9 Light reception lens 10 Holding member 11 Vertical drive coil 12 Yoke 13a 13b magnet 14 left and right drive coil 15 U-shaped yoke 16a 16b magnet

Claims (3)

Wherein a lens for passing the laser light emitted from the emitting means, and a lens holder for holding the lens, and a fixed base fixed to the attachment object, the lens holder with respect to the fixed base of the fixed state A cantilever support means provided between the fixed base and the lens holder so as to be cantilevered by the fixed base so as to be displaceable in the vertical and horizontal directions when the optical axis of the lens is the longitudinal direction; Drive means for driving the holder in the vertical and horizontal directions,
The lens holder includes a lens holding portion for holding the lens, and a connecting portion provided in parallel with the lens holding portion and connected to the cantilever support means;
The fixed base, the cantilever support means, the drive means, and the connecting portion of the lens holder are arranged on the same side of the optical axis ,
The connecting portion of the lens holder is offset toward the fixed base with respect to the lens holding portion in the optical axis direction, and a part of the driving means is provided in the offset connecting portion. laser beam scanning actuator, characterized in that there. A lens for passing laser light emitted from the emitting means; a lens holder for holding the lens; a fixed base fixed to an attachment target; and the lens holder with respect to the fixed base in the fixed state. A cantilever support means provided between the fixed base and the lens holder so as to be cantilevered by the fixed base so as to be displaceable in the vertical and horizontal directions when the optical axis of the lens is the longitudinal direction; Drive means for driving the holder in the vertical and horizontal directions,
The lens holder includes a lens holding portion for holding the lens, and a connecting portion provided in parallel with the lens holding portion and connected to the cantilever support means;
The fixed base, the cantilever support means, the drive means, and the connecting portion of the lens holder are arranged on the same side of the optical axis,
The cantilever support means is composed of four left and right direction displacement springs each having one end coupled to the lens holder at four locations on the top, bottom, left and right, and each other end of the left and right direction displacement spring. A movable support portion, and four vertical displacement springs provided so as to connect the base to the movable support portion at four locations on the upper, lower, left and right sides,
The drive means comprises a yoke fixed to the base and a magnetic coil provided on the movable side,
The magnetic coil is disposed in at least one of a horizontal span and a vertical span in the four horizontal displacement springs and the four vertical displacement springs. The laser beam scanning actuator according to claim 1.     3. The laser beam scanning actuator according to claim 2, wherein the left-right direction displacement spring and the up-down direction displacement spring are formed of leaf springs.

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