JP5598831B2 - Scanning distance measuring device - Google Patents

Description

  The present invention relates to a scanning distance measuring apparatus that scans measurement light in a measurement target space and measures the distance to the measurement target based on the measurement light and reflected light from the measurement target existing in the measurement target space.

  This type of scanning distance measuring device can safely stop a machine by detecting the approach of a human or object to a navigation sensor as a visual recognition sensor for a robot or an unmanned vehicle, or a door opening / closing sensor or a dangerous device. Safety sensor, ETC system sensor that detects the shape of the vehicle and counts the number of vehicles passing, and detects the number of people by detecting the number of people Used for sensors and monitoring sensors that detect the presence or absence of intruders in the monitoring area, and scans the measurement light output from the light projecting unit that outputs measurement light toward the measurement target space. And a light receiving unit that detects reflected light from the measurement object existing in the measurement target space, and the distance to the measurement target is measured based on the measurement light and the reflected light detected by the light receiving unit. .

  As such a scanning distance measuring apparatus, Patent Document 1 includes a light projecting unit including a laser light source 504 and a lens 505, a light receiving lens 508, and a light receiving element 509 such as a photodiode, as shown in FIG. A light receiving / receiving part, a light projecting / receiving mirror 503 attached to the rotating shaft 501 of the motor 502, and a reflection mirror 506 for deflecting the measuring light from the light projecting part toward the light projecting / receiving mirror 503. Among the measurement lights deflected toward the measurement target space, the reflected light from the obstacle 507 in the measurement target space is deflected toward the light receiving unit 509 by the light projecting / receiving mirror 503, and the motor 502 There has been proposed a scanning distance measuring device 500 in which measurement light is scanned in a horizontal plane by rotation of.

Further, in Patent Document 2, as shown in FIG. 14, light is emitted by a light projecting unit 201, a light receiving unit 202 disposed opposite to the optical axis P of measurement light output from the light projecting unit 201, and a motor 210. A cap member 204 that is driven to rotate about the axis P, and is disposed on the upper surface of the upper wall of the cap member 204 at a predetermined inclination angle with respect to the optical axis P, and the measurement light from the light projecting unit 200 is the optical axis P. A projection mirror 206 that deflects in a direction perpendicular to the optical axis P, and is fixed to the lower surface of the upper wall of the cap member 204 at a predetermined inclination angle with respect to the optical axis P. A scanning distance measuring apparatus 200 including a light receiving mirror 208 that deflects reflected light from R toward a light receiving unit 202 has been proposed.
US Pat. No. 5,455,669 JP 2006-349449 A

  The scanning distance measuring device disclosed in Patent Document 1 described above includes a deflection mirror that deflects measurement light from a light projecting unit to a measurement target space, and a deflection mirror that deflects reflected light from the measurement target space to a light receiving unit. In order to deflect reflected light having a large optical path diameter toward the light receiving portion at the periphery of the mirror, it is necessary to form the light projecting / receiving mirror 503 on a deflecting surface having a large area. Furthermore, since the optical path length for guiding the reflected light to the light receiving portion becomes long, there is a problem that the aperture of the light receiving lens 508 becomes large and it is difficult to reduce the size of the apparatus.

  In the scanning distance measuring device disclosed in Patent Document 2, since the light projecting mirror 206 and the light receiving mirror 208 are arranged close to each other via the upper wall portion of the cap member 204, the light projecting of the light projecting mirror is performed. The distance between the optical axes of the optical axis and the light-receiving optical axis of the light-receiving mirror is inevitably small, and the blind spot at a short distance can be reduced to a practically non-problem. Since the light receiving mirror can be made small, the scanning distance measuring device can be miniaturized.

  However, since the light projecting mirror 206 and the light receiving mirror 208 are separated by the cap member 204 and the optical paths of the measurement light and the reflected light are separated, a light shielding sheet or the like is attached so as to contact the transparent window intentionally or carelessly. In this case, even if the measurement light output from the light projecting unit 201 is reflected from the light shielding sheet, the reflected light does not enter the light receiving unit, and the function as a scanning distance measuring device is impaired. There was a problem that reliability could not be secured.

  In view of the above-described problems, an object of the present invention is to provide an inexpensive scanning rangefinder that can easily detect that an optical window is covered with a light-shielding sheet or the like while allowing for downsizing. .

In order to achieve this object, the first characteristic configuration of the scanning distance measuring device according to the present invention is that the measurement light output from the light projecting unit is measured as described in claim 1 of the claims. A first deflecting member that deflects toward the space, a light receiving lens that collects reflected light from the measurement object existing in the measurement target space, and a reflected light that has passed through the light receiving lens , sandwiched therebetween deflected toward the light projecting section and the oppositely disposed light-receiving portion, the first deflecting member and the optical system deflecting surface has a different second deflecting member, wherein around the predetermined axis optical system A scanning distance measuring device that measures a distance to the measurement object based on measurement light and reflected light detected by the light receiving unit, and is deflected by the first deflection member. The reflected measurement light is incident on the second deflecting member. An area within the road, there an optical member to be output from a region spaced in the radial direction of the incident light from the optical axis of the incident light path to the point that provided the scanning mechanism.

According to the above-described configuration, the measurement light deflected by the first deflecting member is a region in the incident optical path of the reflected light to the second deflecting member, and extends from the optical axis of the incident optical path in the radial direction of the incident light. Since the light is output from the separated area , even when a light shielding sheet or the like is attached to the optical window, a part of the reflected light from the light shielding sheet or the like enters the second deflecting member along the incident light path, Based on such measurement light and reflected light, it is possible to reliably detect the presence of a foreign substance such as a light shielding sheet at a close distance.

In addition to the first feature configuration described above, the second feature configuration is a region in the incident light path of the reflected light to the second deflection member, in addition to the first feature configuration described above. Thus, the region through which the measurement light passes is cut out.

  According to the above configuration, the measurement light deflected by the first deflecting member passes through the notched region of the light receiving lens, so that the measurement light is appropriately refracted by the light receiving lens and appropriately enters the measurement target space. Can be output.

  According to the third feature configuration, in addition to the first feature configuration or the second feature configuration described above, the optical member includes the second deflection member and the second deflection member. The deflecting surface is constituted by the first deflecting member in which the deflecting surface is extended and formed in a part of the region along the scanning direction.

  According to the above-described configuration, when the measurement light output from the extension area to the second deflection member of the first deflection member to the measurement target space is reflected by a foreign object such as a light shielding sheet, one of the reflected light is reflected. Since the portion enters the region adjacent to the extension region along the scanning direction on the deflection surface of the second deflection member, it is possible to reliably detect the presence of foreign matter such as a light sheet.

  The fourth characteristic configuration is that, in addition to the third characteristic configuration described above, the first deflection member and the second deflection member are integrally formed as described in the fourth aspect.

  According to the above-described configuration, the optical member is integrally formed so that the angle formed by the deflection surface of the first deflection member and the deflection surface of the second deflection member becomes a predetermined angle, thereby deflecting each of the measurement light and the reflected light. It is not necessary to adjust the incident angle and the reflection angle on the surface, and the scanning distance measuring device can be easily assembled with a small number of parts and with high accuracy.

  In the fifth feature configuration, as described in claim 5, in addition to the third feature configuration or the fourth feature configuration described above, the measurement light deflected by the first deflection member is measured in the optical system. It is in the point provided with the cylindrical guide member which guides to object space.

  According to the above-described configuration, the measurement light deflected by the first deflection member passes through the cylindrical guide member and is guided to the measurement target space, so a part of the measurement light output from the light projecting unit However, it is possible to eliminate the inconvenience that stray light generated by reflection inside the apparatus is erroneously detected by the light receiving unit.

  In the sixth feature configuration, in addition to the first feature configuration described above, in the sixth feature configuration, the optical member causes the second deflection member to transmit the measurement light deflected by the first deflection member. It is in the point comprised by the 3rd deflection | deviation member provided with the two reflective surfaces made to translate so that it may output from the inside of the incident optical path of the reflected light to.

  According to the above-described configuration, the optical axis of the measurement light deflected toward the measurement target space by the first deflection member is deflected by the two reflecting surfaces of the third deflection member, and the measurement light is directed to the second deflection member. The reflected light is translated so as to be output from the incident light path.

In the seventh feature configuration, as described in claim 7, in addition to the sixth feature configuration described above, in the light receiving lens , a region in the incident light path of the reflected light to the second deflection member, The region through which the measurement light passes is notched, and the third deflection member is disposed in the notch portion of the light receiving lens.

  According to the above configuration, the measurement light deflected by the first deflecting member passes through the third deflecting member disposed in the notch portion of the light receiving lens, so that the measuring light is appropriately refracted by the light receiving lens. It can output toward the measurement object space.

  As described above, according to the present invention, it is possible to provide an inexpensive scanning distance measuring device that can easily detect that the optical window is covered with a light-shielding sheet or the like while allowing a reduction in size. Became.

  Hereinafter, a first embodiment of a scanning distance measuring device according to the present invention will be described.

  As shown in FIG. 1, the scanning distance measuring device 1 according to the present invention includes a light-transmitting optical window 2 a formed on a curved surface having a substantially semicircular shape in a cross-sectional view, between an upper housing 21 and a lower housing 22. A monitor display unit 79 that can determine the state of the device 1 is provided on the front surface of the upper housing 21. A pair of cable clamps 78 for connecting a signal cable for taking out distance information detected by the apparatus 1 to the outside is attached to the upper surface of the back housing 23 arranged to face the optical window 2a.

  The scanning distance measuring device 1 modulates measurement light output from a light source LD such as a laser and irradiates the object R through the optical window 2a, and receives the reflected light from the object R through the optical window 2a. The distance is detected and detected, and AM (Amplitude Modify) method and TOF (Time of Flight) method have been put into practical use as the measurement light modulation method.

As shown in FIGS. 11A and 11, the AM method photoelectrically converts measurement light modulated by a sine wave and its reflected light, and calculates a phase difference Δφ between these signals. This is a method for calculating the distance from the phase difference Δφ, and the TOF method photoelectrically converts the measurement light modulated in a pulse shape and its reflected light as shown in FIGS. This is a method for calculating the distance from the delay time Δt between signals, and the scanning distance measuring apparatus 1 to which the present invention is applied can employ any of the above-described methods.
[Equation 1]
L = Δφ · C / (4π · f)
[Equation 2]
L = Δt · C / 2

  As shown in FIGS. 2 and 3, the scanning distance measuring device 1 projects measurement light into the housings 21, 22 and 23 whose inner wall surfaces are covered with a light absorbing member such as a dark curtain that absorbs stray light. The light unit 3 and the light receiving unit 5 that detects the reflected light are arranged to face each other along the optical axis L 1, and the scanning mechanism 4 that rotates and scans the measurement light is disposed between the light projecting unit 3 and the light receiving unit 5.

  The scanning mechanism 4 includes a cylindrical rotating body 8 that rotates the optical system 9 around a rotation axis P that coincides with the optical axis L <b> 1 that connects the light projecting unit 3 and the light receiving unit 5, and a motor 11 that rotationally drives the rotating body 8. It is configured with.

  The rotating body 8 includes a cylindrical peripheral wall portion 8a having a reduced diameter at the lower end portion and a top plate portion 8b, and is rotatably supported by a hollow shaft 13 via a bearing 12 provided on an inner peripheral surface thereof. .

  The motor 11 includes a rotor made up of a magnet 11b attached to the outer peripheral surface of the lower end portion of the peripheral wall 8a having a reduced diameter, and a stator made up of a coil 11a arranged on the casing side. The rotating body 8 is configured to be rotatable around the rotation axis P by the interaction with 11b.

  The light projecting unit 3 includes a light emitting element 3a using a semiconductor laser and a drive circuit 3b for the light emitting element 3a. The light emitting element 3a has an optical axis L1 and an axis P of measurement light output therefrom. An optical lens 3c that is fixedly disposed on the upper housing 21 so as to coincide with each other and that makes the beam diameter of light constant on the optical axis L1 is disposed.

  The light receiving unit 5 is fixedly disposed inside the rotating body 8 so as to face the light projecting unit 3 with the scanning mechanism 4 sandwiched on the rotation axis P, and a light receiving element 5a formed of an avalanche photodiode that detects reflected light. The amplifier circuit 5b amplifies the reflection signal photoelectrically converted by the light receiving element 5a.

  The rotating body 8 includes a first deflection mirror 9a as a first deflection member that deflects the measurement light output from the light projecting unit 3 along the optical axis L1 by 90 degrees toward the measurement target space, and the measurement target space. The light receiving lens 9c that collects the reflected light from the existing measurement object R and the reflected light that has passed through the light receiving lens 9c are directed 90 toward the light receiving unit 5 that is disposed opposite to the light projecting unit 3 along the optical axis L1. An optical system 9 having a second deflecting mirror 9b as a second deflecting member that deflects the lens is attached.

  That is, the measurement light emitted from the light projecting unit 3 along the optical path La along the optical axis L1 is deflected by the first deflection mirror 9a into the optical path Lb along the optical axis L2 perpendicular to the optical axis L1, and then the optical The reflected light from the measurement object that has passed through the window 2a and is irradiated onto the measurement target space and passed through the optical window 2a along the optical path Lc along the optical axis L3 parallel to the optical axis L2 is converged by the light receiving lens 9c. The light is deflected by the second deflecting mirror 9b to the optical axis L4 equal to the optical axis L1 and guided to the light receiving unit 5.

  An opening 8c for attaching the light receiving lens 9c is formed in a part of the peripheral wall 8a of the rotating body 8, and a notch 8d for attaching the deflection mirrors 9a and 9b is formed in the top plate 8b corresponding to the opening 8c.

  As shown in FIG. 4A, deflecting surfaces 91 and 92 coated with gold or aluminum as a reflecting member are formed on two orthogonal planes of an optical member 90 integrally formed of resin or optical glass. A first deflection mirror 9a that deflects measurement light 90 degrees toward the measurement target region with respect to the optical axis L1 is configured by one deflection surface 91, and a light receiving unit that reflects reflected light along the optical axis L4 by the second deflection surface 92 A second deflecting mirror 9 b that deflects 90 degrees toward 5 is configured.

  A central portion on the upper end side of the second deflection surface 92 is cut out, and a first deflection mirror 9 a is formed to extend in the cutout portion 95, and the top plate portion 8 b of the rotating body 8 is formed on both sides of the first deflection mirror 91. A reference surface 93 that regulates the mounting posture is formed, and the reference surface 93 is formed with an attachment hole 94 in which a thread is formed on the inner peripheral surface.

  As shown in FIGS. 2 and 3, the deflection mirrors 9a and 9b that are integrally formed are inserted through the opening 8c formed in the rotating body 8, and the peripheral surface of the notch 8d formed in the top plate 8b and By joining the above-described reference surface 93 and screwing screws into the mounting holes 94, the deflection mirrors 9a and 9b are fixed to the rotating body 8, and then the light receiving lens 9c is fixed to the opening 8c.

  A part of the light receiving lens 9c on the upper side from the lens center is cut out linearly, and a cutout part is formed in which the central part is cut out in the lens center direction. A hollow cylindrical guide member 9d for guiding the measurement light deflected by the first deflection mirror 9a to the measurement target space is fixed to a notch 8d formed in the top plate portion 8b of the rotating body 8, and the tip of the guide member 9d The side end portion is arranged so as to extend from the notch formed in the light receiving lens 9c, and the base end side end portion of the guide member 9d is arranged to contact the lower end side of the first deflection mirror 9a. That is, a region of the light receiving lens through which the measurement light passes is cut out.

  The outer periphery of the guide member 9d is covered with a light shielding member, and the measurement light deflected by the first deflection mirror 9a passes through the guide member 9d and is guided to the measurement target space. Accordingly, it is possible to eliminate the inconvenience that stray light generated by a part of the measurement light output from the light projecting unit 3 leaking into the rotating body 8 is erroneously detected by the light receiving unit 5.

  The optical window 2a provided between the upper housing 21 and the lower housing 22 is a measurement object R that is irradiated with the measurement light output from the light projecting unit 3 by the scanning mechanism 4 and is present in the measurement target space. In order to detect the reflected light reflected by the light receiving unit 5, the light receiving unit 5 has a certain width in the vertical direction and is arranged so as to be slightly inclined inward from the upper end to the lower end, and the measurement light is about about the rotation axis P. It is arranged so as to be able to scan in a range of 250 degrees. As a result, it is possible to scan a wide space while it is difficult for dust or the like to accumulate on the surface of the optical window 2a.

  In addition, as shown in FIG. 12, you may arrange | position the said optical window 2a so that it may incline slightly inside from a lower end to an upper end. The inclination angle of the optical window 2a and the scanning angle around the rotation axis P are appropriately set according to the installation position and application of the scanning distance measuring device.

  When the above-described optical member 90 is employed, as shown in FIG. 2, the second deflection mirror 9b in which the measurement light deflected by the first deflection mirror 9a is installed at an installation angle different from the installation angle of the first deflection mirror 9a. Even when a light shielding sheet or the like is affixed around the optical window 2a, a part of the reflected light from the light shielding sheet or the like is along the incident light path Lc. Then, the light enters the second deflecting mirror 9b, and it is possible to reliably detect the presence of a foreign substance such as a light shielding sheet at a close distance based on such measurement light and reflected light.

  Specifically, as shown in FIG. 5, the measurement light output from the extension area 96 to the second deflection mirror 9b in the deflection surface of the first deflection mirror 9a into the measurement target space is a foreign object such as a light shielding sheet. When the light is reflected, a part of the reflected light enters the region 97 adjacent to the extension region 96 along the scanning direction on the deflection surface of the second deflection mirror 9b, so that there is a foreign substance such as a light sheet. Can be detected. The notch 95 formed in the second deflection surface 92 is not limited to the central portion on the upper end side, and the measurement light is output so that the measurement light is output from the incident light path Lc of the reflected light to the second deflection mirror 9b. As long as the optical path Lb is formed, it may be formed at the upper end of the second deflection surface 92.

  That is, the above-described optical member composed of the second deflection mirror 9a and the first deflection mirror 9a in which the deflection surface is extended and formed in a part of the region along the scanning direction among the deflection surfaces of the second deflection mirror 9b. 90 is a second deflecting member 9b having a deflecting surface having a setting angle different from the setting angle of the deflecting surface of the first deflecting member 9b, for measuring light deflected by the first deflecting member 9a, which is a feature of the present invention. The optical member which outputs from the inside of the incident optical path Lc of the reflected light to is comprised.

  As such an optical member 90, in addition to the optical member 90 shown in FIG. 4A, as shown in FIG. 4B, the upper end side of the first deflection mirror 9a is formed flush with the reference surface 93, As shown in FIG. 4C, the upper end side of the first deflection mirror 9a is formed flush with the reference surface 93, and the lower end side of the first deflection mirror 9a protrudes from the deflection surface of the second deflection mirror 9b. It may be formed. In any case, it is sufficient that the measurement light in the optical path La output along the optical axis L1 from the light projecting unit 3 has an area that can be deflected in a direction perpendicular to the optical axis L1.

  A slit plate 15a having a plurality of optical slits formed in the circumferential direction on the outer peripheral surface of the rotator 8 is installed, and a photo interrupter 15b is disposed on the rotation path of the slit plate 15a, thereby scanning the rotator 8. A scanning angle detector 15 for detecting an angle is configured.

  In the upper part of the lower housing 22, a signal processing board that controls the rotation of the scanning mechanism 4 and drives and controls the light emitting element 3 a to calculate the distance to the measurement object based on the reflected signal detected by the light receiving unit 5. 7 is arranged.

  In the signal processing board 7, the rotation angle of the scanning mechanism 4 is calculated based on the pulse signal input from the scanning angle detector 15, and the direction in which the measurement object corresponding to the reflected light is located is grasped.

  A light guide member 17 such as a prism for guiding reference light for correcting the distance calculated by the signal processing board 7 is disposed on the inner wall portion of the back housing 23 facing the optical window 2a.

  Each time the measurement light is scanned by the scanning mechanism 4, based on the reference light that is directly incident on the light receiving unit 5 from the light projecting unit 3 via the light guide member 17, the light projecting unit 3 in the distance measuring device The reference distance to the light receiving unit 5 is calculated, and based on this, the distance calculated based on the reflected light from the object in the measurement target space is corrected.

  The output signal line from the light receiving unit 5 is inserted into the internal space of the hollow shaft 13 and connected to the signal processing board 7.

  Next, a second embodiment of the scanning distance measuring device according to the present invention will be described.

  In the second embodiment, the measurement light deflected by the first deflection mirror 9a is reflected to the second deflection mirror 9b having a deflection surface having an installation angle different from the installation angle of the deflection surface of the first deflection mirror 9b. The configuration of the optical member 90 that outputs from within the incident optical path Lc is different from that of the first embodiment described above. Below, it demonstrates centering around the structure of the optical member 90 used as a difference, and attaches | subjects the same code | symbol about a common component, and abbreviate | omits detailed description.

  As shown in FIGS. 6 and 7, the rotating body 8 incorporated in the scanning distance measuring device 10 has a measurement light 90 output from the light projecting unit 3 along the optical axis L <b> 1 toward the measurement target space. A first deflecting mirror 9a as a first deflecting member that deflects the light, a light receiving lens 9c that condenses the reflected light from the measuring object R existing in the measurement target space, and a reflected light that has passed through the light receiving lens 9c as an optical axis. An optical system 9 including a second deflecting mirror 9b as a second deflecting member that deflects 90 degrees toward the light receiving unit 5 disposed to face the light projecting unit 3 along L1 is attached.

  Deflection surfaces 91 and 92 coated with gold or aluminum as a reflecting member are formed on two orthogonal planes of an optical member 90 integrally formed of resin or optical glass, and the first deflection surface 91 forms an optical axis L1. The first deflecting mirror 9a is configured to deflect the measuring light by 90 degrees toward the measurement target region, and the first deflecting surface 92 deflects the reflected light by 90 degrees toward the light receiving unit 5 along the extension of the optical axis L1. A second deflection mirror 9b is configured.

  A reference surface 93 for restricting the mounting posture of the rotating body 8 to the top plate portion 8b is formed on both side surfaces of the optical member 90 with the deflection surfaces 91 and 92 therebetween, and the reference surface 93 is threaded on the inner peripheral surface. A mounting hole 94 in which a strip is formed is formed.

  The integrally formed deflection mirrors 9a and 9b are inserted from the opening 8c formed in the rotating body 8, and the peripheral surface of the notch 8d formed in the top plate 8b and the reference surface 93 described above are joined and attached. By screwing screws into the holes 94, the deflection mirrors 9a and 9b are fixed to the rotating body 8, and then the light receiving lens 9c is fixed to the opening 8c.

  A part of the light receiving lens 9c on the upper side from the lens center is cut out linearly, and a cutout part is formed in which the central part is cut out in the lens center direction. A third deflection member 9e is fixed to a notch 8e formed in the top plate portion 8b of the rotating body 8, and one end thereof is disposed so as to be fitted into the notch formed in the light receiving lens 9c.

  The third deflecting member 9e reflects the measurement light deflected by the first deflecting mirror 9a to the second deflecting mirror 9b having a deflecting surface having a setting angle different from the setting angle of the deflecting surface of the first deflecting mirror 9a. Are provided with two deflecting mirrors 9f and 9g to be translated and a mirror holding portion 9h whose outer periphery is covered with a light shielding member.

  The deflection mirrors 9f and 9g are arranged so that their deflection surfaces face each other, and are held by a mirror holding portion 9h whose outer periphery is covered with a light shielding member so as to be inclined by 45 degrees with respect to the optical axis L2.

  The measurement light deflected by the first deflecting mirror 9a to the optical axis L2 perpendicular to the optical axis L1 is deflected by the third deflecting mirror 9f along the optical axis parallel to the optical axis L, and further by the fourth deflecting mirror 9g. It is deflected to an optical axis L2 ′ parallel to the optical axis L2.

  That is, the measurement light deflected by the first deflection member 9a is reflected in the incident light path Lc of the reflected light to the second deflection member 9b having a deflection surface having an installation angle different from the installation angle of the deflection surface of the first deflection member 9a. The optical member output from is constituted by a third deflecting member 9e.

  Accordingly, the measurement light deflected by the first deflection mirror 9a is output from the incident optical path Lc of the reflected light to the second deflection mirror 9b installed at an installation angle different from the installation angle of the first deflection mirror 9a. Even when a light shielding sheet or the like is pasted around the optical window 2a, a part of the reflected light from the light shielding sheet or the like enters the second deflection mirror 9b along the incident light path Lc. Based on such measurement light and reflected light, it is possible to reliably detect the presence of a foreign substance such as a light shielding sheet at a close distance.

  In the above-described embodiment, the third deflecting member 9e is configured by the pair of deflecting mirrors 9f and 9g held by the mirror holding portion 9h. However, as shown in FIG. It may be composed of prisms arranged such that the deflection surfaces face each other and both are inclined by 45 degrees with respect to the optical axis L2.

  The first deflecting mirror 9a and the second deflecting mirror 9b are preferably formed integrally from the viewpoint of mounting accuracy, but are not necessarily formed integrally, and the first deflecting mirror 9a and the second deflecting mirror 9b are not necessarily formed. May be configured as separate bodies and attached to the top plate portion 8b of the rotating body 8 at a predetermined angle.

  Hereinafter, the distance to the measurement object is measured based on the measurement light and the reflected light by the signal processing board 7 incorporated in the scanning rangefinders 1 and 10 described in the first and second embodiments. The calculation processing to be performed will be described.

  The signal processing board 7 is provided with a TOF type signal processing circuit 70 that calculates the distance to the measurement object based on the reference light detected by the light receiving unit 5 in synchronization with the output timing of the measurement light.

  As shown in FIG. 9, the signal processing circuit 70 includes a light emission control unit 71 that outputs a light emission drive signal synchronized with the angle signal based on the angle signal indicating the scanning angle output from the scanning angle detection unit 15, and the measurement. When the scanning unit 4 is not positioned at the reference rotation position where light is incident on the light guide member 17, the measurement light detection unit 72 that detects the electrical signal output from the light receiving unit 5 as a measurement light signal, and the scanning unit 4 A reference light detection unit 73 that detects an electrical signal output from the light receiving unit 5 as a reference light signal when positioned at the reference rotation position, and the scanning type based on the reference light signal detected by the reference light detection unit 73 A correction value calculation unit 74 that calculates a correction value for the measurement distance between the distance measuring device and the measurement object, a measurement distance is calculated based on the measurement light signal detected by the measurement light detection unit 72, and the measurement distance and the correction value are calculated. Based on the final measurement distance A distance calculating unit 75 that calculates, from the angle signal and the final measurement distance by calculating the position of the measurement object is configured to include a like system control unit 76 for outputting.

  When the system is powered on, a motor drive signal is output from the system controller 76 to the motor control circuit 77, and the motor 11 is driven at a predetermined speed by the motor control circuit 77.

  A pulse signal output from the scanning angle detection unit 15 as the motor is driven to rotate is input to the light emission control unit 71, and the light emission control unit 71 grasps the output direction of the measurement light from the scanning unit 4 based on the pulse signal. The

  The slit interval of the slit plate 15a constituting the scanning angle detector 15 is formed to be different from other rotation positions at a preset reference rotation position of the rotating body, and the reference rotation position is detected based on the waveform of the pulse signal. The rotation angle from the reference rotation position is calculated by counting the number of pulses from the reference rotation position.

  As shown in FIG. 10, when the measurement timing signal is input to the light emission control unit 71 from the system control unit 76 that calculates the measurement timing based on the pulse signal that is an angle signal output from the scanning angle detection unit 15. A light emission drive signal S1 having a predetermined duty ratio is output from the light emission control unit 71 to the light projecting unit 3 at a predetermined timing based on the measurement timing signal.

  In the light projecting unit 3 that has received the light emission drive signal S1, the semiconductor laser 3a is driven by the drive circuit 3b to output pulsed measurement light.

  When the scanning unit 4 is not located at the reference rotation position, the reflected light S4 reflected by the measurement object in the output measurement light S2 (S2a) is photoelectrically converted by the light receiving element 5a, amplified by the amplifier circuit 5b, and measured light. It is output to the detector 72.

  The measurement light detector 72 detects the electrical signal as the reflected signal S5a and outputs the detected signal to the distance calculator 75. When the scanning unit 4 is located at the reference rotation position, the measurement light detection unit 72 is configured not to detect a signal.

  On the other hand, when the scanning unit 4 is positioned at the reference rotation position, the output measurement light S2 (S2b) is not emitted to the outside of the apparatus as the reference light S3 and is received by the light receiving unit 5 via the light guide member 17 described above. Then, the amplifier circuit 51 performs photoelectric conversion of the reference light S3, and the converted electric signal is amplified to a level at which signal analysis is possible and output.

  The reference light detection unit 73 detects the electrical signal as the reference signal S5b and outputs it to the correction value calculation unit 74. When the scanning unit 4 is not located at the reference rotation position, the reference light detection unit 73 is configured not to detect a signal.

  In the correction value calculation unit 74, a time difference t1 between the light emission drive signal S1 corresponding to the measurement light S2b and the reference signal S5b is calculated, and a correction value ΔL for the measurement distance between the scanning distance measuring device and the measurement object is calculated from the time difference t1. It calculates based on [Formula 2]. The correction value ΔL is obtained as a distance L obtained by substituting the time difference t1 for T in [Expression 2].

  The distance calculation unit 75 calculates a time difference t2 between the light emission drive signal S1 corresponding to the measurement light S2a and the reflection signal S5a, and calculates the measurement distance L1 from the time difference t2 based on [Equation 2]. In addition, the measurement distance L1 is calculated | required as the distance L obtained by substituting the time difference t2 for T of [Formula 2].

  Then, the distance calculation unit 75 calculates the final measurement distance L2 by subtracting the correction value ΔL from the calculated measurement distance L1.

  The system controller 76 outputs the direction and position of the measurement object from the angle signal output from the scanning angle detector 15 and the final measurement distance L2. That is, the direction of the measurement object relative to the scanning distance measuring device is calculated from the angle signal, and the distance L2 from the scanning distance measuring device to the measurement object is specified from the final measurement distance.

  As described above, the measurement object is located in the measurement object space in the range of about 250 degrees around the rotation axis P when the light emitting element is intermittently driven in the same period as the measurement timing signal output in a predetermined period. Direction and distance.

  In the measurement light detection unit 72 or the reference light detection unit 73, time differences t1 and t2 between the light emission drive signal S1 and the reflection signal S5a or the reference signal S5b are detected based on the rising timing of each signal. The rise timing can be easily detected by providing a comparator that detects when each signal exceeds a predetermined threshold.

  In the detection of the rise timing by the comparator, an error occurs due to the influence of a minute fluctuation of the rise of the signal due to the intensity of the reflected light. Therefore, the following method can be adopted to absorb such an error. .

  For example, the rising waveform of the reflected signal or the reference signal is time-integrated, for example, up to a range indicating the peak value, and the correction value map data of the rising timing corresponding to each of a plurality of integrated values stored in the memory in advance is used. If the rising timing data corresponding to the integrated value is derived, the rising timing of the reflected signal or the reference signal can be accurately calculated. The characteristic is that the rise time fluctuation caused by the fluctuation of the intensity of the reflected light or the reference light has a correlation with the integral value of the signal.

  Further, the peak value of the reflected signal or the reference signal is calculated, and the correction value corresponding to the peak value is derived from the map data in which the correction values corresponding to the plurality of peak values are stored in the memory in advance. The rising timing of the reflected signal or reference signal obtained by the comparator may be corrected. The characteristic is that the rise time fluctuation has a correlation with the peak value of the signal.

  As another method, a differential signal is generated by time-differentiating the reflected signal or the reference signal, and the center of gravity position on the time axis of the positive region of the differential signal is obtained as the rising position of the reference signal and the reflected signal. There may be.

  In addition, the method of calculating the center of gravity position on the time axis of the rising portion of the reflected signal or reference signal to obtain the rising timing, or by approximating the rising portion of the reflected signal or reference signal by linear approximation or polynomial approximation, For example, a method of calculating the position of the intersection with the offset level of the output signal as the rising timing may be adopted.

  In the above-described embodiment, the scanning distance measuring device according to the present invention employs the TOF method that photoelectrically converts the measurement light modulated in a pulse shape and its reflected light, and calculates the distance from the delay time between these signals. In this case, the AM method is used in which the measurement light modulated with a sine wave and the reflected light are photoelectrically converted, the phase difference between these signals is obtained, and the distance is calculated from the phase difference. It may be.

  In this case, from the light projecting unit 3 that has received the light emission drive signal from the light emission control unit 71, measurement light modulated by a sine wave is emitted from the semiconductor laser by the drive circuit 3b.

  Then, the correction value calculation unit 74 and the distance calculation unit 75 calculate and calculate the phase difference between the measurement light output from the light emitting element 3a and the measurement light signal or reference light signal output from the amplification circuit 84. The distance or the correction value is calculated by substituting the obtained phase difference into (Equation 1).

  The light emitting element used for the light source is not limited to the semiconductor laser, and other light emitting elements such as a light emitting diode may be used.

  Any of the above-described embodiments is an example of the present invention, and the specific configuration of each part such as the specific shape, configuration, material used, circuit configuration for signal processing of the scanning distance measuring device is the present invention. Needless to say, the design can be changed as appropriate within the range where the effects of the above are achieved.

1 shows a scanning distance measuring device according to the present invention, wherein (a) is a front view showing the appearance of the scanning distance measuring device, (b) is a plan view, and (c) is a side view. 1 is a schematic longitudinal sectional view showing a first embodiment of a scanning rangefinder according to the present invention. The front view of the principal part which shows 1st embodiment of the scanning rangefinder by this invention (A) is a perspective view of the optical member which shows 1st embodiment, (b) is a perspective view of the optical member which shows another embodiment, (c) is a perspective view of the optical member which shows another embodiment. Explanatory drawing of the optical path of the measurement light by the optical member shown to Fig.4 (a), and the optical path of reflected light Schematic longitudinal sectional view showing a second embodiment of the scanning distance measuring device according to the present invention. The front view of the principal part which shows 2nd embodiment of the scanning rangefinder by this invention. The front view of the principal part which shows another embodiment of the scanning distance measuring device by this invention. Block diagram of a signal processing circuit of a scanning distance measuring device according to the present invention. Explanatory drawing showing timing of optical signal waveform and electrical signal waveform of scanning distance measuring device It is explanatory drawing of the measurement principle of a scanning distance measuring device, (a) is explanatory drawing of AM system, (b) is explanatory drawing of TOF system. Schematic longitudinal sectional view showing another embodiment of the scanning distance measuring device according to the present invention. Schematic longitudinal sectional view of a conventional scanning rangefinder Schematic longitudinal sectional view of a conventional scanning rangefinder

1: Scanning distance measuring device 2a: optical window 2: housing 21: upper housing 22: lower housing 23: back housing 3: light projecting unit 3a: light emitting element 3b: drive circuit 4: scanning mechanism 5: light receiving unit 5a: light receiving Element 5b: Amplifier circuit 7: Signal processing circuit board 8: Rotating body 9: Optical system 9a: First deflection mirror 9b: Second deflection mirror 9c: Light receiving lens 9d: Guide member 9e: Third deflection member 9f, 9g: Deflection Mirror 9h: Mirror holding unit 11: Motor 15: Scan angle detection unit 17: Light guide member 70: Signal processing circuit 71: Light emission control unit 72: Measurement light detection unit 73: Reference light detection unit 74: Correction value calculation unit 75: Distance calculation unit 76: system control unit 90: optical member 91: first deflection surface 91
92: Second deflection surface 92
93: Reference plane 94: Mounting hole

Claims (7)

A first deflection member that deflects the measurement light output from the light projecting unit toward the measurement target space, a light reception lens that collects reflected light from the measurement target existing in the measurement target space, and the light reception lens. An optical system comprising: a first deflecting member and a second deflecting member having a different deflecting surface that deflects transmitted reflected light toward a light receiving unit disposed opposite to the light projecting unit across the first deflecting member. System and a scanning mechanism that rotates the optical system around a predetermined axis, and measures the distance to the measurement object based on the measurement light and the reflected light detected by the light receiving unit Because
The measurement light deflected by the first deflecting member is a region in the incident optical path of the reflected light to the second deflecting member, from a region separated from the optical axis of the incident optical path in the radial direction of the incident light A scanning distance measuring device provided with an optical member for output in the scanning mechanism. The scanning distance measuring device according to claim 1, wherein a region of the light receiving lens that is in an incident optical path of reflected light to the second deflecting member and through which the measurement light passes is cut out.   The optical member includes the second deflecting member and the first deflecting member having a deflecting surface extending in a part of a region along the scanning direction of the deflecting surface of the second deflecting member. The scanning rangefinder according to claim 1 or 2.   The scanning distance measuring device according to claim 3, wherein the first deflection member and the second deflection member are integrally formed.   The scanning distance measuring device according to claim 3 or 4, wherein the optical system includes a cylindrical guide member that guides the measurement light deflected by the first deflection member to a measurement target space.   A third deflecting member provided with two deflecting surfaces for translating the optical member so that the measuring light deflected by the first deflecting member is output from the incident light path of the reflected light to the second deflecting member. The scanning rangefinder according to claim 1, comprising: Of the light receiving lens , a region in the incident optical path of the reflected light to the second deflecting member, the region through which the measurement light passes is cut out, and the third deflecting member is formed in the notched portion of the light receiving lens. The scanning rangefinder according to claim 6, which is arranged.

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