JP4461199B1 - Distance measuring device - Google Patents

Abstract

Disclosed is a distance measuring device that can identify with high accuracy whether light incident on a distance measuring device is reflected light from a front carriage, and can eliminate erroneous stops of the carrier caused by erroneous detection.
A scanning unit that scans a modulated measurement light in a planar manner at a front portion of a transport carriage that travels along a track, and a time between the measurement light scanned by the scanning unit and reflected light from a detection object Based on the reflected light from the retroreflective member arranged at the rear of the transport carriage that travels ahead by the distance measuring device is arranged with a distance calculating unit that calculates the distance from the delay to the detected object A distance measuring device for detecting an inter-vehicle distance between transport carriages, wherein a plurality of scanning angles of measurement light scanned by a scanning unit, a distance corresponding to each scanning angle calculated by a distance calculating unit, and each scanning angle An identification unit is provided for identifying whether or not the reflected light is from the retroreflective member based on any two correlations among the reflected light intensities corresponding to.
[Selection] Figure 4

Description

  The present invention provides a scanning unit that scans a modulated measurement light in a planar shape at the front of a transport carriage that travels along a track, and the time between the measurement light scanned by the scanning unit and the reflected light from a detection object. Based on the reflected light from the retroreflective member disposed at the rear of the transport carriage that travels in front of the distance measuring device by arranging a distance measuring device that calculates the distance from the delay to the detected object The present invention relates to a distance measuring device that detects the inter-vehicle distance between transport carts.

  In a semiconductor device manufacturing facility, in order to automatically transfer a semiconductor wafer between manufacturing apparatuses, a wafer carrier apparatus containing a plurality of semiconductor wafers placed on a load port provided in each manufacturing apparatus is transferred. A transport cart is used.

  In order to avoid contact with people and machines, the transport cart is composed of a traveling rail installed in the upper space of the manufacturing facility, that is, a traveling section that self-travels along the track, and an article accommodating section that is supported by the traveling section. An elevating mechanism is incorporated that elevates and lowers an elevating body having a chuck mechanism for gripping an object to be conveyed along a predetermined elevating path.

  The track has a complicated shape with not only a simple linear part but also a curve, a branching part, a merging part, etc. in order to transport the wafer carrier device according to the layout of the manufacturing equipment. Run.

  In recent years, in order to increase the transfer efficiency of a wafer carrier device, it is required that a large number of transfer carts travel at high speed on the same track, and accordingly, the inter-vehicle distance between the transfer carts is shortened.

  Therefore, in Patent Document 1, as shown in FIG. 15, in order to avoid a rear-end collision of the transport carriage 8, the transport carriage 8 is provided with an inter-vehicle distance sensor such as a laser distance meter, and the inter-vehicle distance measured by the inter-vehicle distance sensor is set. Based on this, a technology is disclosed in which a relative speed with respect to the forward carriage 6 is calculated and the traveling speed of the own vehicle is controlled based on the relative speed.

  Further, in Patent Document 2, as shown in FIG. 16, an optical sensor device 1 that detects the distance between itself and the immediately preceding transport vehicle is attached to each of the transport vehicles V and V ′. The light projected from the optical sensor device 1 is applied to the immediately preceding transport vehicle V ′, and when the distance between both transport vehicles is detected and the distance falls below a certain value, the rear transport vehicle is decelerated or stopped. Thus, a device for preventing collision between both transport vehicles is disclosed.

  Then, a reflector 3 is installed on the outside of the curved portion of the rail R substantially along the rail R, and the light projected from the optical sensor device 1 of the rear transport vehicle V is reflected by the reflector 3. The distance between the two transporting vehicles traveling along the curved portion of the rail R is detected by applying the curved portion of the rail R to the transport vehicle V ′ immediately before traveling.

  The curved portion of the rail R is often provided in the vicinity of the wall surface, and the vehicle V is stopped by erroneously detecting the wall surface as an obstacle by detecting light projected from the transport vehicle V and reflected by the wall surface. This is to solve the problem.

JP 2007-25745 A JP 2001-249718 A

  However, in the technique described in Patent Document 1, when the forward transport carriage travels on the track curve, the front transport carriage is detected because the front transport carriage deviates from the optical axis of the measurement light. In addition to being unable to do so, there is a risk that reflected light from various facilities installed in the factory, other traveling carts, and the like may be erroneously detected as reflected light from a transport cart traveling in front.

  Moreover, in the technique described in Patent Document 2, even when the forward carriage is traveling on the curve of the track, the forward carriage can be detected. For this reason, reflection along the rails is possible. A board installation space is required. However, a highly integrated semiconductor manufacturing facility has a problem that a space between tracks becomes narrow and a space for installing a reflector along the rail cannot be secured.

  Furthermore, in any technique, if stray light other than light reflected from the front transport carriage is incident on the distance measuring device provided in the transport carriage, there is a risk that the transport carriage will stop or decelerate due to a false detection of the front transport carriage. It was not solved.

  In view of the above-described problems, the object of the present invention is to identify with high accuracy whether the light incident on the distance measuring device is reflected light from the front transport carriage, and to prevent erroneous stoppage of the transport carriage due to erroneous detection. The point is to provide a distance measuring device that can be eliminated.

In order to achieve the above-mentioned object, a first characteristic configuration of the distance measuring device according to the present invention includes a scanning unit that scans the modulated measuring light in a planar manner at the front part of the transport carriage that travels along the track, A distance measuring device comprising a distance calculation unit that calculates a distance to the detected object from a time delay between the measurement light scanned by the scanning unit and the reflected light from the detected object is disposed, and travels forward by the distance measuring device. A distance measuring device that detects an inter-vehicle distance between transport carriages based on reflected light from a retroreflective member disposed at a rear portion of the transport carriage, wherein the retroreflective member is a micro prism type retroreflective reflection The distance measuring device includes a light source for measuring light, which is a laser diode that emits light in a single mode, and a light receiving unit that receives reflected light. The light receiving unit receives light from the light source. The first mirror that reflects toward the object to be detected And a second mirror that reflects the reflected light from the detection object toward the light-receiving unit, a scanning unit configured by a rotation mechanism that rotates about the optical axis, and the first mirror to the detection object. A first polarizing element that is polarized in a first direction provided in an optical path that is reflected toward the second direction, and a second polarization that is polarized in a second direction different from the first direction provided in the optical path of reflected light that is incident on the second mirror from the detection target. two is configured to include a polarizing element, a plurality of scan angle of the scanned measurement light by the scanning unit, and a distance corresponding to the scanning angle calculated by the distance calculation unit, the reflected light corresponding to each scanning angle It is in the point provided with the identification part which discriminate | determines whether it is the reflected light from the said retroreflection member based on at least any two correlation among these intensity | strengths.

  When the measurement light scanned in a planar shape by the scanning unit is applied to the retroreflective member disposed at the rear of the front carriage, the measurement light is reflected from the retroreflective member toward the distance measuring device, and the distance The calculation unit calculates the distance to the retroreflective member from the time delay between the measurement light and the reflected light, and obtains the distance to the retroreflective member for each scanning angle of the measurement light.

  That is, for each scanning angle of the measurement light scanned by the scanning unit, the distance is obtained by the distance calculation unit, and the intensity of the reflected light at that time is obtained. The retroreflective member has a certain width, and the width of the retroreflective member is detected based on the reflected light retroreflected from each incident point where the measurement light scanned in a plane is incident on the retroreflective member. can do. On the other hand, when the measurement light is irradiated onto a metal cover of a manufacturing device or other equipment, it is specularly reflected. Therefore, if the light is irradiated on a reflective surface perpendicular to the optical axis of the measurement light, it is detected by the distance measuring device. If the optical axis of the measurement light and the reflecting surface are slightly inclined, they are not detected by the distance measuring device.

  Therefore, the identification unit includes a plurality of scanning angles of the measurement light scanned by the scanning unit, a distance corresponding to each scanning angle calculated by the distance calculating unit, and an intensity of reflected light corresponding to each scanning angle. Based on at least any two correlations, it is possible to identify whether or not the reflected light is from the retroreflective member.

  For example, when a substantially constant distance is continuously detected at a scanning angle within a predetermined range, it can be identified as reflected light from the retroreflective member, and when a distance is detected at one point within a predetermined range of scanning angle, It becomes possible to discriminate that the reflected light is due to specular reflection, not the reflected light from the retroreflective member.

Further, a laser diode that emits light in a single mode has a characteristic of outputting light linearly polarized in a predetermined direction. For example, when the measurement light is reflected by the first mirror toward the front of the distance measuring device, the polarization direction of the measurement light is maintained, and if the polarization direction is parallel to the first direction, the measurement light passes through the first polarization element. Is irradiated.

The light incident on the micro prism type retroreflective member has a characteristic that the polarization direction is rotated by the prism in the second direction and reflected. Therefore, if a second polarizing element that polarizes in the second direction is provided in the optical path of the reflected light, only the light incident on the retroreflective member is guided to the light receiving element, so that erroneous detection of stray light is avoided. It will be possible.

As described in claim 2, the second characteristic configuration is based on the attenuation characteristic of the measurement light output from the first polarizing element in accordance with the scanning angle in addition to the first characteristic configuration described above. In addition, a correction calculation unit for correcting the intensity of the reflected light received by the light receiving unit is provided .

According to the first characteristic configuration, when the first mirror rotates, the polarization angle of the light output from the laser diode is gradually inclined, and the intensity of the measurement light transmitted through the first polarizing element is attenuated. The intensity decay follows the square law of cos θ. Therefore, the intensity of the reflected light that eliminates the influence of the attenuation of the intensity due to the rotation of the first mirror can be obtained by correcting the intensity of the reflected light received by the light receiving unit by the inverse square law of cos θ by the correction calculation unit. become.

In the third feature configuration, in addition to the first or second feature configuration described above, the identification unit is obtained with respect to the measurement light scanned by the scanning unit. The continuity is evaluated based on the correlation and the correlation obtained for the measurement light scanned in the past by the scanning unit, and whether or not the reflected light is from the retroreflective member. The point is to identify .

According to the above configuration, the distance for each scanning angle and the intensity of the reflected light obtained each time the measuring light is scanned by the scanning unit are compared with the distance for each scanning angle and the intensity of the reflected light obtained in the past. Thus, it is possible to identify whether or not the reflected light is from the same retroreflective member based on the difference.

The fourth characterizing feature of the can, as noted in the claim 4, in addition from the first described above in the third one of characteristic structure of the transport carriage, the running portion which runs along the track, The article storage unit is supported by a traveling unit, and the track is configured by a support unit that supports a traveling wheel provided in the traveling unit and a cover member that is connected to the support unit and surrounds the traveling unit, The distance measuring device and the retroreflective member are arranged in the traveling unit so as to be located inside the track.

  If the traveling unit located inside the track is equipped with a distance measuring device and a retroreflective member, external light is blocked by the cover member that forms the track so that stray light other than stray light caused by the measurement light can be eliminated. Become. Further, even when the transport carriage traveling in the front passes the curve of the track and the optical axis of the measurement light deviates from the retroreflective member, the measurement light is reflected by the inner surface of the cover member and The light enters the retroreflective member installed on the traveling carriage, and the reflected light from the retroreflective member is reflected by the inner surface of the cover member and guided to the distance measuring device. The inter-vehicle distance can be detected well.

  As described above, according to the present invention, it is possible to identify with high accuracy whether or not the light incident on the distance measuring device is reflected light from the front transport carriage, and eliminate the erroneous stop of the transport carriage due to erroneous detection. A distance measuring device capable of being provided can be provided.

Schematic perspective view of manufacturing equipment, wafer carrier equipment, transport cart, etc. in semiconductor device manufacturing equipment Schematic diagram of transfer cart and wafer carrier device It is explanatory drawing of a conveyance trolley | bogie and a wafer carrier apparatus, (a) is a top view, (b) is a front view, (c) is a side view. Explanatory drawing of traveling rail and traveling section Explanatory drawing of distance measuring device (A) is explanatory drawing of a laser, (b) is explanatory drawing of distance calculation based on measurement light and reflected light. (A) is explanatory drawing of a retroreflection member, (b) is explanatory drawing of the change of the polarization direction by reflection by a retroreflection member. Functional block diagram of transport cart Functional block diagram of ranging device Explanatory drawing of the scanning angle of the scanning unit and the polarization direction of the measurement light (A) is explanatory drawing of attenuation | damping of the intensity | strength of measurement light by providing a scanning angle and a polarizing element, (b) is explanatory drawing of correction | amendment of the intensity | strength of measurement light by a correction calculating part. (A) is explanatory drawing of the retroreflective member detection by a distance measuring device, (b) is explanatory drawing of a scanning angle and distance, (c) is explanatory drawing which a front conveyance trolley detects. (A) is explanatory drawing of a scanning angle and intensity | strength, (b) is explanatory drawing of distance and intensity | strength. (A) is explanatory drawing of the time-sequential distance characteristic of the retroreflection member detected corresponding to the scanning light scanned with a curve, (b) is the optical path of the scanning light scanned with a curve, and reflected light Illustration Illustration of prior art Illustration of prior art

  An embodiment in which the distance measuring apparatus according to the present invention is applied to an unmanned transport cart provided in a semiconductor device manufacturing facility will be described. In addition, the code | symbol attached | subjected to drawing used by the following description is unrelated to the code | symbol attached | subjected to drawing used for description of a prior art.

  As shown in FIGS. 1, 2, and 3, in a semiconductor device manufacturing facility 1, various manufacturing apparatuses 2 (2 a to 2 l) for sequentially performing a predetermined process on a semiconductor wafer are provided. A traveling rail 10 serving as a track is suspended from the ceiling along the traveling rail 10, and a plurality of transport carts 20 are provided on the traveling rail 10 so as to freely travel.

  The transport carriage 20 grips the wafer carrier device 4 in which a plurality of semiconductor wafers placed on the load port 3 of each manufacturing apparatus 2 is accommodated, and between each manufacturing apparatus 2 based on a command from the controller 90. And the wafer carrier device 4 is configured to travel between the stockers 5 for temporarily storing them.

  The manufacturing apparatus 2 (2a to 2l) is divided into bays 6 and 7 and installed for each manufacturing process.

  The traveling rail 10 has a complicated shape including not only a simple straight portion but also a curve, a branching portion, a merging portion, and the like. For example, an inter-process rail 10a that connects the bays 6 and 7, an in-process rail 10b that connects the manufacturing apparatuses 2 installed in the bays 6 and 7, a branch rail 10c that connects the inter-process rail 10a and the in-process rail 10b, A retraction rail 10d for temporarily retreating the transport carriage 1 traveling in the in-process rail 10b, a bypass rail 10e for loading and unloading the wafer carrier device 4 to and from the stocker 5 are configured.

  The branch rail 10c is a rail that connects the inter-process rail 10a and the in-process rail 10b, and the traveling carriage 20 that travels travels along the branch rail 10c, so that the inter-process rail 10a and the in-process rail 10b are connected. Come and go with each other.

  The retreat rail 10d is provided to be branched from the in-process rail 10b, and is used, for example, when the transport carriage 20 is temporarily retracted from the in-process rail 10b for maintenance of the transport carriage 20 or the like.

  The bypass rail 10e is used when the wafer carrier device 4 branched from the inter-process rail 10a and temporarily held in the stocker 5 by the transport carriage 20 traveling on the inter-process rail 10a is used.

  The traveling rail 10 is formed in a concave shape whose cross section opens downward. Specifically, the support unit 11 that supports a travel wheel 27 provided in the travel unit 21 to be described later is connected to the support unit 11 and includes the cover member 12 that surrounds the travel unit 21. The traveling rail 10 is formed of a light, strong, and aluminum drawn material, and is suspended from the ceiling by a support member 13 at an appropriate interval. However, the material and the installation direction on the ceiling are not limited thereto.

  In the traveling rail arranged in a straight line, the side wall portion of the cover member 12 is partially opened to reduce the weight.

  As shown in FIGS. 2, 3, and 4, the transport carriage 20 includes a traveling unit 21 that travels along the support unit 11 of the traveling rail 10 and an article storage unit 22 that is supported by the traveling unit 21. Yes.

  The traveling unit 21 includes a main frame 26 that serves as a base, a pair of left and right traveling wheels 27 that are pivotally supported on axles provided in front and rear of the main frame 26, and a traveling motor 28 that drives the traveling wheels 27 (not shown). )).

  Further, the main frame 26 is provided with a pair of left and right guide wheels (not shown) at positions where the main frame 26 is substantially in contact with the inner surface of the cover member 12 of the traveling rail 10, and the traveling portion 21 is moved to the left and right in the traveling direction by the guide wheels. It is configured to be able to travel without slipping.

  Further, the main frame is provided with a branching roller (not shown) for selecting a branching guide (not shown) provided in the cover member 12 of the traveling rail 10, for example, from the inter-process rail 10a to the branching rail. When the travel route is switched to 10c, the travel route is switched when the branch roller of the transport carriage 20 selects one of the branch guides in response to a command from the controller 90. ing.

  The traveling unit 21 is not limited to the configuration in which the traveling wheel 27 is driven by the traveling motor 28, and the linear motor is constituted by a permanent magnet laid in the traveling rail 10 and a core provided on the traveling unit 21 side. The structure which drive | works by comprising may be sufficient.

  On the upper part of the main frame 26, power supply units 30 are provided on the left and right. The power supply unit 30 includes an E-shaped core 31 and a coil 32 wound around a part of the core 31.

  High frequency power is applied to the power supply line 15 supported by the power supply line holder 14 on the inner wall side surface of the cover member 12, and the high frequency power is induced in the coil 32 to transmit power without contact. In addition, all the electric power required for the conveyance carriage 20 is supplied by this non-contact power feeding method.

  The command from the controller 90 is transmitted to the communication unit 75 provided in the traveling unit 21 of the transport carriage 20 described later via the power supply line 15 and the power supply unit 30.

  Note that the power supply means to the transport carriage 1 is not limited to the non-contact power supply method using the power supply unit 30 and the power supply line 5 described above.

  The article storage unit 22 incorporates an elevating motor 25 (not shown) as an elevating mechanism that elevates and lowers an elevating body 24 including a chuck mechanism 23 that holds the wafer carrier device 4 along a predetermined elevating path. .

  The lifting body 24 is connected to the lifting mechanism 22 by a plurality of belts 29. The elevating motor 25 is configured to raise and lower the elevating body 24 by winding the belt 29 and feeding it out. The belt 29 incorporates a power supply line and a signal line for supplying power from the traveling unit 21 to the chuck mechanism 23.

  The chuck mechanism 23 includes a pair of claw portions for gripping the gripped portion 4 a on the upper surface of the wafer carrier device 4 and a gripping motor 33 (not shown), and drives the gripping motor 33. Thus, the gripper 4a of the wafer carrier device 4 is configured to be gripped or released when the claw portion is in a gripping posture or an opening posture.

  Further, the front of the traveling direction of the main frame 26 of the traveling unit 21 is a measurement for detecting the inter-vehicle distance between the transporting carts based on the reflected light from the retroreflective member installed at the rear of the transporting cart traveling forward. A distance device 40 is provided, and a retroreflective member 60 that reflects light emitted from the distance measuring device 40 installed in the front part of the transport carriage traveling behind is provided in the rear part in the traveling direction. The distance measuring device 40 and the retroreflective member 60 are arranged in the traveling unit 21 so as to be located inside the traveling rail 10 and constitute a distance measuring device that detects the inter-vehicle distance between the transport carriages.

  In the present embodiment, since the transport carriage 20 is configured to advance only along the travel route, the distance measuring device 40 is provided only at the front portion of the transport carriage 20 so that the transport carriage 20 traveling forward can be detected. The retroreflective member 60 is provided only in the rear part. When the transport cart 20 is configured to be able to travel in the front-rear direction, the distance measuring device 40 and the retroreflective member 60 are provided in each of the front and rear portions of the transport cart 20.

  As shown in FIG. 7A, as the retroreflective member 60, a micro prism type retroreflective member in which a plurality of three reflecting surfaces 61, 62, and 63 that intersect at right angles is arranged is used. It is a rear portion in the traveling direction of the traveling unit 21 and is attached at an appropriate height that can reflect light from the distance measuring device 40 of the rear carriage 20. In the micro prism type retroreflective member, the measurement light is retroreflected when incident on the retroreflective member 60 at an angle of 45 degrees or less, and when measured light is incident at an angle greater than 45 degrees, the retroreflective member is measured. Reflective properties do not appear.

  As shown in FIG. 5, the distance measuring device 40 includes a light projecting unit 41 that modulates light from a light source 41 a for measurement light with a predetermined modulation signal and outputs the light as measurement light inside a substantially cylindrical housing 50. A scanning unit 47 that rotationally scans the measurement light toward the distance measurement target space, a light receiving unit 42 that detects reflected light reflected by the detected object by the photoelectric conversion element, and a light projecting unit 41. A control circuit 80 including a distance calculation unit that calculates the distance to the object based on the output measurement light and the reflected light reflected by the detected object is provided.

  The distance measuring device 40 will be described in detail. The housing 50 of the distance measuring device 40 has a shape in which two cylinders having different diameters overlap each other in the vertical direction in FIG. A translucent window 53 having a constant width in the vertical direction is formed along the housing 50 over a side wall (shown on the right side wall in FIG. 5) excluding a part from the entire circumference of the entire circumference. Via the optical window 53, the measurement light output from the light projecting unit 41 and the reflected light from the detection object can be transmitted and received.

  The inner peripheral surface of the housing 50 other than the light-transmitting window 53 is composed of a light absorbing wall covered with a light absorbing member such as a dark curtain having an uneven surface on the surface in order to completely block light and prevent reflection. Yes.

  The light projecting unit 41 is arranged such that a light source 41a composed of a laser diode that emits light in a single mode outputs measurement light downward in FIG.

  As shown in FIG. 6A, a laser diode that emits light in a single mode has a polarization characteristic perpendicular to the junction surface, and the emitted beam of the laser diode emits narrow radiation in the direction in which light spreads on the junction surface. The light is emitted at an angle and is emitted at a wide radiation angle in a narrowly confined direction. Therefore, the light projecting unit 41 includes the optical lens 54 on the optical path of the light output downward from the light source 41a, and is configured to make the beam diameter of the light constant.

  The scanning unit 47 includes a first mirror 44 that reflects light from the light source 41a toward the detected object, a second mirror 45 that reflects reflected light from the detected object toward the light receiving unit 42, and an optical path of the reflected light. A light receiving lens 55 that focuses the reflected light is provided, and is configured to be rotated by a motor as the rotation mechanism 46. The rotation axis of the scanning unit 47 is configured to coincide with the optical axis 43 of the light source 41a.

  The first mirror 44 and the second mirror 45 are inclined 45 degrees with respect to the optical axis 43, respectively, and are arranged so that the optical axis of the measurement light and the optical axis of the reflected light are parallel to each other.

  Further, the scanning unit 47 includes a slit plate 56 having an optical slit, and a scanning angle detection unit 58 that detects the scanning angle of the scanning unit 47 in cooperation with the photo interrupter 57 installed on the inner peripheral surface of the housing 50. Constitute.

  The light receiving unit 42 includes, for example, a light receiving element such as an avalanche photodiode and an amplifier circuit that amplifies the photoelectrically converted signal. The light source 41 a is disposed on the optical axis 43 so as to face the light source 41 a while being accommodated in the scanning unit 47.

  More specifically, the light receiving unit 42 is disposed on the upper end surface of the hollow shaft 59 that supports the scanning unit 47, and always maintains a stationary state regardless of the rotation operation of the scanning unit 47 by the rotation mechanism 46. It has become. In addition, an output signal from the light receiving unit 42 is connected to a control circuit 80 described later by a signal line (not shown) inserted into the internal space of the hollow shaft 59.

  Further, a first polarizing element 48 that is polarized in the first direction is attached to the optical path reflected from the first mirror 44 toward the detection object, on the outer peripheral surface of the light transmission window 53, and the second mirror 45 extends from the detection object. A second polarizing element 49 that is polarized in a second direction different from the first direction is attached to the optical path of the reflected light that is incident on the light.

  In the case where the transparent window 53 is made of a material such as acrylic resin or glass that does not have polarization characteristics, the polarizing elements 48 and 49 may be attached to the inner surface side of the transparent window 53.

  Each of the first polarizing element 48 and the second polarizing element 49 is a polarizing filter, and the first polarizing element 48 is, for example, light having a polarization plane in the vertical direction in FIG. The second polarizing element 49 allows light having a polarization plane in a direction (for example, 90 degrees) different from that of the light L1 in the first direction (hereinafter referred to as “second light” to be referred to as “light L1 in the first direction”). Directional light L2 ”).

  As shown in FIG. 7B, when the light L1 polarized in the first direction projected through the first polarizing element 48 of the distance measuring device 40 enters the retroreflective member 60, first, the reflecting surface 61 is reflected. In the process of reflecting to the reflecting surface 62 and then reflecting to the reflecting surface 63, the light L2 polarized in the second direction rotated 90 degrees from the vertically polarizing surface to the horizontally polarizing surface, After passing through the two polarizing elements 49, the light receiving unit 42 detects the light.

  On the other hand, the measurement light passes through the opening formed on the side wall of the traveling rail 10 and is reflected from an external metallic equipment cover or the like, or is irradiated to the feeder holder 14 or the like provided inside the traveling rail 10, The reflected light reflected by the inner wall surface does not pass through the second polarizing element 49 and is not received by the light receiving unit 42 because the polarization plane of the light L1 in the first direction is maintained. In general, since metal is specularly reflected, the reflected light is not received by the light receiving unit 42 when the incident angle of the measurement light is not 90 degrees. In this way, the distance measuring device 40 can avoid erroneous detection of stray light, and can detect only the retroreflective member 60 disposed at the rear portion of the transport carriage 20 traveling forward.

  Next, the control units of the transport carriage 20 and the distance measuring device 40 will be described in detail.

  As shown in FIG. 8, the main frame 26 of the traveling unit 21 of the transport carriage 20 includes a microcomputer including a CPU, ROM, and RAM, and includes a traveling unit control unit 70 that controls the traveling unit 21. It has been.

  The traveling unit control unit 70 transmits a command signal 71 output from the central controller 90 that controls each conveyance carriage 20 via the feeder 15 that is disposed in the cover member 12 of the traveling rail 10 and the communication unit 75. And driving the traveling motor 28, driving the branch roller to switch the traveling route, and controlling the lifting motor 25 of the lifting body 24. A signal from the control circuit 80 is transmitted.

  The transport carriage 20 is appropriately provided with a sensor or the like for detecting that it is on the load port 3 of the manufacturing apparatus 2 designated by the controller 90, and a signal from the sensor is input to the traveling unit control unit 70. It is configured.

  The chuck mechanism control unit 73 is electrically connected to the traveling unit control unit 72 via a signal line 74 incorporated in the belt 29, and is gripped based on a command signal 71 from the controller 90 in the same manner as the traveling unit control unit 72. The holding motor 33 is driven to drive the claw portion so that the gripped portion 4a of the wear carrier device 4 is gripped or released. In addition, what is necessary is just to provide suitably the sensor etc. which detect that a nail | claw part grasped or released the to-be-gripped part 4a of the wear carrier apparatus 4. FIG.

  As shown in FIG. 9, a control circuit 80 of the distance measuring device 40 is provided at a lower portion in the housing 50 of the distance measuring device 40.

  The control circuit 80 includes a microcomputer including a CPU, a ROM, and a RAM, an arithmetic circuit for distance measurement, and the like, and a light emission control unit 84 that controls the light emission timing of the light projecting unit 41, and a scan. A distance calculation unit 81 for calculating a distance to the detection object from a time delay between the measurement light scanned by the unit 47 and the reflected light from the detection object, and a plurality of scanning angles θ of the measurement light scanned by the scanning part 47 The retroreflective member based on at least any two correlations among the distance D corresponding to each scanning angle θ calculated by the distance calculation unit 81 and the intensity I of the reflected light corresponding to each scanning angle θ. Based on the attenuation characteristic of the measurement light output from the first polarizing element 48 in accordance with the scanning angle θ, the reflection received by the light receiving unit 42, for identifying whether or not the light is reflected from 60 Correct light intensity I That the correction operation unit 83 or the like is formed.

  The distance calculation unit 81 calculates the distance from the distance measuring device 40 to the retroreflective member 60 by the TOF method.

  As shown in FIG. 6B, the TOF method outputs measurement light obtained by modulating laser light into pulse light from the light projecting unit 41 based on the pulse signal of the light emission control unit 84, and the light emission signal of the measurement light This is a method of calculating the distance by the following formula 1 based on the time delay with respect to the reception signal of the reflected light from the detected object (retroreflective member 60) received by the light receiving unit 42. Here, C is the speed of light, and ΔT is the time difference.

[Equation 1]
L = (1/2) × C / ΔT

  In this embodiment, the TOF method is adopted as the distance calculation method of the distance measuring device 40, but the AM method may be adopted. The AM method is a method in which a measurement light obtained by modulating a laser beam with a sine wave is output, and a distance is calculated by the following formula 2 based on the phase difference between the reflected light reflected by the detection object and the measurement light. is there. Here, φ is the measured phase difference, C is the speed of light, and F is the modulation frequency.

[Equation 2]
L = (1/2) × (φ / 2π) × C / F

  The slit interval of the slit plate 56 provided in the scanning unit 47 is formed so as to be different from others at a preset reference position of the rotating body, and the scanning angle detection unit 58 determines the reference position based on the waveform of the pulse signal. And the scanning angle θ from the reference position is calculated by counting the number of pulses from the reference position.

  Here, the attenuation characteristic of the measurement light output from the first polarizing element 48 according to the scanning angle θ will be described.

As shown in FIG. 10, when the laser diode is arranged so as to output light linearly polarized in the first direction on the front side in the traveling direction of the transport carriage (scanning angle θ = 0 °), the first mirror 44 The measurement light reflected toward the front surface of the distance measuring device 40 in a state where the polarization direction is maintained is irradiated to the front in the traveling direction via the first polarizing element 48. Since the intensity I of the light is proportional to the square of the magnitude of the electric field E, the intensity I ₀ of the measurement light at this time is I ₀ = E ₀ ² cos ² (0).

However, when the first mirror 44 rotates with the rotation of the scanning unit 47, the polarization angle of the measurement light reflected by the first mirror 44 gradually tilts with respect to the vertical polarization characteristics of the laser diode. For example, when the scanning angle θ = ± 45 degrees, the intensity I ₄₅ of the measurement light that has passed through the first polarizing element 48 is I ₄₅ = E ₄₅ ² cos ² (45).

That is, the light intensity I _θ at the scanning angle θ is expressed by I _θ = I ₀ cos ² θ, and attenuates as the scanning angle θ is changed from 0 degree to ± 90 degrees. Therefore, as shown in FIG. 11A, the measurement light is emitted from the first polarizing element 48 when the scanning angle θ = 0, and the measuring light is emitted from the first polarizing element 48 when the scanning angle θ = ± 90 degrees. It will not be done.

  Therefore, as shown in FIG. 11B, the correction calculation unit 83 corrects the intensity of the reflected light received by the light receiving unit 42 by the inverse square law of cos θ. As a result, the intensity of the measurement light excluding the influence of the attenuation of the intensity due to the rotation of the first mirror 44 is obtained. Hereinafter, the intensity I of reflected light refers to the intensity corrected by the correction calculation unit 83.

  The measurement light scanned in a planar shape by the scanning unit 47 (here, a horizontal plane, but may be a vertical plane or a plane inclined at a predetermined angle from the horizontal plane) is returned to the front carriage 20. When the reflective reflector 60 is irradiated, the measurement light is reflected from the retroreflective member 60 toward the distance measuring device 40, and the distance calculation unit 81 from the time delay between the measurement light and the reflected light to the retroreflective member 60. The distance to the retroreflective member 60 is obtained for each scanning angle θ of the measurement light, and the intensity of the reflected light at that time is obtained. The retroreflective member 60 has a certain width, and based on the reflected light retroreflected from each incident point where the measurement light scanned in a planar shape is incident on the retroreflective member 60, the retroreflective member 60 has a predetermined width. The width can be detected.

  However, when the measurement light is irradiated onto a metal cover or the like of a manufacturing apparatus or other equipment, it is specularly reflected. Therefore, if the light is irradiated onto a reflection surface perpendicular to the optical axis of the measurement light, the distance measuring device 40 Although detected, if the optical axis of the measurement light and the reflection surface are slightly inclined, the reflected light is not detected by the distance measuring device 40. Therefore, the reflected light is continuously generated with a certain width with respect to the operation angle of the measurement light. It will not be detected.

  Therefore, the identification unit 82 corresponds to a plurality of scanning angles θ of the measurement light obtained by scanning by the scanning unit 47 and stored in the RAM of the control circuit 80, and each scanning angle θ calculated by the distance calculation unit 81. Based on the correlation between at least one of the distance D to be reflected and the intensity I of the reflected light corresponding to each scanning angle θ, it is identified whether or not the reflected light is from the retroreflective member 60, and the traveling unit is controlled. The identified data is transmitted to the unit 70.

  First, the identification unit 82 performs recursion based on the correlation between the plurality of scanning angles θ of the measurement light scanned by the scanning unit 47 and the distance D corresponding to each scanning angle θ calculated by the distance calculation unit 83. The case where it is identified whether it is the reflected light from the reflective member 60 is demonstrated.

  Since the retroreflective member 60 has a certain width, the retroreflective member 60 is reflected on the basis of the reflected light retroreflected from each incident point where the measurement light scanned in a plane is incident on the retroreflective member 60. Can be detected.

For example, as shown in FIG. 12A, at the distance D _x , the retroreflective member 60 is detected in the range of the scanning angle θ = 0 ± θ _x , and its width is A _x = 2D _x tan θ _x . I know that.

For example, the ROM of the control circuit 80 has a correlation between the distance D _x to the retroreflective member 60 calculated by the distance calculation unit 83 and the scanning angle range θ corresponding to the width A _x of the retroreflective member 60. The table data which prescribes is stored. That is, when the distance D _x to the retroreflective member becomes longer, the width A _x detected by the distance measuring device, that is, the scanning angle range θ becomes narrower, and when the distance D _x becomes shorter, the width A _x detected by the distance measuring device. In other words, since the correlation that the scanning angle range θ becomes wide is established, the scanning angle corresponding to the width of the retroreflective member 60 is calculated for each distance D _x calculated by the distance calculation unit 81 to the retroreflective member 60. Table data defining an allowable range indicating an upper limit and a lower limit is stored. For example, the identification unit 82 is detected if the average distance to the detected object calculated during one scan and the scanning angle range corresponding to the detected object are within the allowable range stored in the ROM. The reflected light is identified as reflected light from the retroreflective member.

As shown in FIG. 12B, it is assumed that the distance measuring device 40 has detected an object in the scanning angle range θ = 0 ± θ _{1 at} a distance D ₁ ahead of the conveyance carriage 20a in the traveling direction. At this time, the width of the object is A ₁ = 2D ₁ tan θ ₁ .

The identification unit 82 includes a distance D ₁ and a scanning angle (width A ₁ ) stored in the RAM by the detection, and a table data of a correlation between the distance D ₁ and the scanning angle (width A ₁ ) stored in the ROM. In comparison, as shown in FIG. 12C, the reflected light is identified as reflected light from the retroreflective member 60b of the front transport carriage 20b. Since the position of the forward traveling direction front distance D ₃ of the conveyance carriage 20a, be detected object in the width B, the identification unit 82 is too small compared to the width at a distance D _3, which is stored in the ROM It can be identified that the light is not reflected light from the retroreflective member.

  Thus, when the identification unit 82 identifies that the reflected light is from the retroreflective member 60b of the transport carriage 20b traveling forward, the distance data is transmitted to the traveling unit control unit 70, and the traveling unit control unit 70 controls the traveling motor 28 to control the traveling speed of the transport carriage 20. Normally, the transport cart 20 is travel controlled at a speed of 3 m / s. For example, if the distance from the front transport cart is 5 m or less, the transport cart 20 is decelerated, and if the distance is 1 m or less, the transport cart 20 is transported. The carriage 20 is controlled to stop, and if it is 300 mm or less, the carriage 20 can be completely stopped to prevent a collision between the carriages.

Next, the identifying unit 82 is based on the correlation between the plurality of scanning angles θ _x of the measurement light scanned by the scanning unit 47 and the intensity I _{x of the} reflected light corresponding to each scanning angle θ _x . The case where it is identified whether it is the reflected light from the reflection member 60 is demonstrated.

For example, in the ROM of the control circuit 80, table data of the correlation between the scanning angle range θ and the intensity I _{x in which} the retroreflective member 60 is detected, for example, when the scanning angle range θ is large, that is, the retroreflective member. The detected intensity I _x becomes stronger when the distance to the distance is short, and the correlation is established that the intensity I _x becomes weak when the scanning angle range θ is small, that is, when the distance to the re-regulating reflecting member is long. Therefore, table data defining an allowable range indicating an upper limit and a lower limit of the scanning angle corresponding to the width of the retroreflective member 60 is stored for each intensity I _x corrected by the correction calculation unit 83. For example, the identification unit 82 has been detected if the average intensity up to the detected object calculated during one scan and the scanning angle range corresponding to the detected object are within the allowable range stored in the ROM. The reflected light can be identified as reflected light from the retroreflective member.

Further, for example, as shown in FIG. 13A, it is assumed that the distance measuring device 40 detects reflected light having a scanning angle range θ = 0 ± θ ₁ and an intensity that is substantially constant I ₁ . The identification unit 82 has a scanning angle range θ = 0 ± θ ₁ and intensity I ₁ stored in the RAM by detection, and an intensity I when the scanning angle range θ = 0 ± θ ₁ stored in the ROM. by comparing ₁ and, if in the difference is allowable range, the reflected light, as shown in FIG. 12 (c), When it is reflected light from the retroreflection member 60b of the front conveyance carriage 20b Identify. Incidentally, also be detected reflected light intensity I ₃ over a scan angle range theta = C ahead in the traveling direction front side of the transporting carriage 20a, the identification unit 82 compares the table data stored in the ROM, It identifies that it is not the reflected light from a retroreflection member. In this case, since the range in which the intensity I ₃ is detected is too small in the scanning angle range θ = C, it can be identified that it is not reflected light from the retroreflective member.

Next, the identification unit 82 performs recursion based on the correlation between the distance D _x corresponding to each scanning angle θ calculated by the distance calculation unit 81 and the intensity I _{x of the} reflected light corresponding to each scanning angle θ. The case where it is identified whether it is the reflected light from the reflective member 60 is demonstrated.

For example, in the ROM of the control circuit 80, the distance D _x corresponding to each scanning angle θ and the intensity I _{x of} reflected light, that is, the intensity I _x of light is inversely proportional to the square of the distance D _x from the light source 41. , the distance to the retroreflection member the greater the intensity I _x of the reflected light D _x becomes shorter, the distance D _x to the retroreflection member smaller the intensity I _x of the reflected light is correlated to become longer relationship Therefore, table data defining an allowable range of the reflected light intensity I _x for the distance D _x or table data defining an allowable range of the distance D _x for the reflected light intensity I _x is stored. For example, if it is within the allowable range of the identification unit 82 is detected intensities I _x of the reflected light intensity I _x is stored in the ROM of the reflected light to the distance D _x of the reflected light, reflected light is detected recursive It can be identified as reflected light from the reflecting member.

As shown in FIG. 13B, it is assumed that the distance measuring device 40 detects reflected light having an intensity I ₁ at a distance D ₁ . Identification unit 82, the intensity _{I 1} at a distance _{D 1} stored in the RAM by the detection, by comparing the intensity _{I 1} at a distance _{D 1} stored in the ROM, the intensity _{I 1} is within the allowable range If there is, the reflected light is identified as reflected light from the retroreflective member 60b of the front carriage 20b as shown in FIG. 12 (c). Even when the reflected light having the intensity I ₃ is detected at the distance D ₃ , the identification unit 82 is out of the predetermined range stored in the table data stored in the ROM, so that it is reflected from the retroreflective member. Identify not light. In this case, since the intensity I ₃ is too small in the distance D ₃ is detected, it can be identified as not a reflected light from the retroreflective member

In the above description, the case where the two transport carts travel along the linear travel rail 10 has been described. For example, as illustrated in FIG. Since the transport carriage moves in the right direction while decelerating, the scanning angle θ and the distance D based on the detected reflected light move in the direction indicated by the lower right arrow in the figure. Become. The range of the scanning angle at which the reflected light is detected is detected because the angle of the retroreflective member of the front transport carriage is inclined with respect to the optical axis of the measurement light of the distance measuring device of the rear transport carriage. scanning angle is smaller than θ = 0 ± θ _1.

  Further, as shown in FIG. 14B, the transport carriage 20b traveling forward passes through the curve of the track, and the optical axis of the measuring light of the distance measuring device of the rear transport carriage 20a deviates from the retroreflective member 60. Even in such a case, the measurement light is reflected by the inner surface of the cover member 12 and is incident on the retroreflective member 60b installed on the transport carriage 20b traveling forward, and is reflected from the retroreflective member 60b. Is reflected on the inner surface of the cover member and guided to the distance measuring device 40a, so that the inter-vehicle distance from the transport carriage 20b traveling forward can be detected well.

  In the above-described embodiment, the configuration has been described in which the identification unit 82 identifies whether or not the reflected light is from the retroreflective member based on the reflected light for each scan of the scanning unit 47. Based on the correlation obtained for the measurement light scanned by the unit 47 and the correlation obtained for the measurement light scanned in the past by the scanning unit 47, the continuity is evaluated, You may comprise so that it may be identified whether it is the reflected light from a retroreflection member.

  In this case, the identification unit 82 obtains the scan angle range θ, the distance D, the intensity I obtained by a certain scan and stored in the RAM of the control circuit 80, and the scan obtained by the next scan and stored in the RAM of the control circuit 80. The angle range θ, the distance D, and the intensity I are compared, and if the difference is within a predetermined allowable range, it is evaluated that there is continuity, and the reflected light from the retroreflective member is identified. Further, identification may be made by any combination of the scanning angle range θ, the distance D, and the intensity I. In this case, the allowable range is a value set in advance for each relative speed by calculating the relative speed with the preceding vehicle by dividing the previous and current calculated distances by the calculation time difference.

For example, FIG. 12 (b), the scanning angle range theta = 0 in the next scan it detects the distance D ₁ over a ± theta _1, the scanning angle range theta = 0 the distance over ± θ ₂ D ₂ Is detected. Then, the identification unit 82 identifies whether or not the reflected light is from the retroreflective member 60, and further compares with the result obtained in the previous scan. In this case, the retroreflective member 60 It can be identified that the distance to is approaching.

Further, FIG. 13 (a), the scanning angle range theta = 0 in the next scan it detects intensity I ₁ over ± theta _1, the scanning angle range theta = 0 intensity over ± θ ₂ I ₂ Is detected. Then, the identification unit 82 identifies whether or not the reflected light is from the retroreflective member 60, and further compares with the result obtained in the previous scan. In this case, the retroreflective member 60 It can be identified that the distance to is approaching.

Furthermore, as shown in FIG. 13B, it is assumed that the intensity I _{2 of the} reflected light is detected at the distance D ₂ in the next scanning in which the intensity I _{1 of the} reflected light is detected at the distance D ₁ . Then, the identification unit 82 identifies whether or not the reflected light is from the retroreflective member 60, and further compares with the result obtained in the previous scan. In this case, the retroreflective member 60 It can be identified that the distance to is approaching.

  In this way, the distance D for each scanning angle θ and the intensity I of the reflected light obtained each time the measuring light is scanned by the scanning unit 47 are used to determine the distance D and the reflected light I for each scanning angle θ obtained in the past. In contrast to the intensity, it is possible to identify whether the reflected light is from the same retroreflective member based on the difference.

  In the above description, the identification unit 82 calculates the distance to the detected object from the time delay between the measurement light scanned by the scanning unit 47 and the reflected light from the detected object, and the scanning unit 47. Any one of a plurality of scanning angles θ of the measurement light scanned by the above, a distance D corresponding to each scanning angle θ calculated by the distance calculation unit 81, and an intensity I of reflected light corresponding to each scanning angle θ Although the configuration for identifying whether or not the light is the reflected light from the retroreflective member 60 based on the two correlations has been described, the scan angle θ, the distance D, and the reflected light intensity I are all combined to achieve a recursive property. It may be configured to identify whether or not the light is reflected from the reflecting member 60. Since the traveling device 21 located inside the traveling rail 10 includes the distance measuring device 40 and the retroreflecting member 60, the external light is blocked by the cover member 12 that forms the track, and therefore stray light caused by the measuring light. The stray light other than can be eliminated.

  In the above-described embodiment, the scanning range of the scanning angle of the distance measuring device 40 is not specified. However, when the scanning angle θ of the distance measuring device 40 is set to 0 ° in front of the conveyance carriage 20 in the traveling direction, the scanning angle. If the range of θ = 0 ± 30 degrees can be measured, when the horizontal width of the traveling rail 10 is 400 mm and the width of the retroreflective member 60 is 200 mm, it is approximately 180 mm in front of the straight traveling rail 10. Since all of the horizontal direction of the retroreflective member 60 can be detected even at a short distance, the distance between the transport carts can be shortened, and the number of transport carts traveling on the traveling rail can be increased. The transfer efficiency of the wafer carrier device can be increased.

  Further, when the radius of curvature R at the central portion is 500 mm at the maximum in the curved portion of the orbit, the scanning angle θ = 0 ± when the distance measuring device 40 sets the scanning angle θ = 0 ° to the front in the traveling direction. If the range of 30 degrees is scanned, the retroreflective member 60d can be sufficiently detected, but the scanning angle range can be set as appropriate according to the value of the radius of curvature R at the center of the curved portion.

  In this embodiment, since the rotation speed of the first mirror and the second mirror 45 by the rotation mechanism is set to 2400 rpm, the measurement light is scanned 40 times per second, and the scanning angle is from −30 degrees to +30 degrees. It is scanned once at about 4.2 msec. The distance is calculated in increments of 0.2 degrees during one scan.

  In the above-described embodiment, a micro prism type retroreflective member is used as the retroreflective member, and the distance measuring device has a light source for measuring light that is a laser diode that emits light in a single mode, and a light receiving device that receives the reflected light. A first mirror that reflects the light from the light source toward the detected object, and a second mirror that reflects the reflected light from the detected object toward the light receiving unit. A scanning unit configured by a rotation mechanism that rotates as an axis, a first polarizing element that is polarized in a first direction provided in an optical path that is reflected from the first mirror toward the detection object, and the second mirror from the detection object Although the example comprised by the 2nd polarizing element which polarizes in the 2nd direction different from the 1st direction prepared in the optical path of the reflected light which injects into a distance, the distance measuring device by this invention is not restricted to such a structure. Absent.

  For example, a laser light source that emits light in a multi-mode or a light source for measurement light composed of a light-emitting diode and a light receiving unit that receives reflected light are arranged on the optical axis so as to reflect light from the light source toward a detection object The first mirror and the second mirror that reflects the reflected light from the detection object toward the light receiving unit are configured by a scanning unit configured by a rotating mechanism that rotates about the optical axis, and the first and second polarizations A distance measuring device that does not include an element may be used.

  Also in this case, at least of the plurality of scanning angles of the measurement light scanned by the scanning unit, the distance corresponding to each scanning angle calculated by the distance calculation unit, and the intensity of the reflected light corresponding to each scanning angle Whether the light is reflected light from the retroreflective member or noise light by including an identification unit that identifies whether the light is reflected light from the retroreflective member based on any two correlations Can be properly identified, and the inter-vehicle distance from the transport carriage traveling in front can be accurately detected.

  In this case, a glass bead retroreflective member may be used instead of the microprism retroreflective member. A glass bead-type retroreflective member is composed of a base material with a reflective film and a reflective layer made of glass beads, which is refracted when light is incident on the glass beads and focuses at a single point on the spherical surface. Reflected by the reflective film on the back of the glass bead, bent again when exiting the glass bead, and reflected in the direction of the light source parallel to the incident light.

  In the above-described embodiment, the configuration in which the distance measuring device and the retroreflective member are arranged in the traveling unit so as to be positioned inside the track has been described. However, the distance measuring device and the retroreflective member are located outside the track. You may arrange | position to a conveyance trolley so that it may be located.

  In the above-described embodiment, the case where the distance measuring apparatus according to the present invention is used in a semiconductor device manufacturing facility has been described. However, the distance measuring apparatus according to the present invention is an arbitrary luggage transport apparatus in which a plurality of transport carts travel on a track. Can be used.

  The above-described embodiments are merely examples of the present invention, and the scope of the present invention is not limited by the description, and the specific configuration of each part is appropriately changed within the scope of the effects of the present invention. It goes without saying that it can be done.

1: Manufacturing equipment 2 (2a to 2l): Manufacturing apparatus 3: Load port 4: Wafer carrier apparatus 4a: Grasping part 5: Stocker 6, 7: Bay 21: Traveling part 27: Traveling wheel 10: Traveling rail 10a: Inter-process rail 10b: In-process rail 10c: Branch rail 10d: Retraction rail 10e: Bypass rail 11: Support section 12: Cover member 13: Support member 14: Feed line holder 15: Feed line 20: Conveying carriage 21: Traveling section 22 : Article storage unit 23: Chuck mechanism 24: Lifting body 25: Lifting motor 26: In-frame 27: Traveling wheel 28: Traveling motor 29: Belt 30: Power feeding unit 31: Core 32: Coil 33: Holding motor 40 : Distance measuring device 60: Retroreflective members 61, 62, 63: Reflecting surface 50: Housing 41: Light projecting part 41 a: Light source 42: Light receiving part 43: Optical axis 44: First 45: second mirror 46: rotating mechanism 47: scanning part 48: first polarizing element 49: second polarizing element 50: housing 51: step part 52: peripheral wall part 53: translucent window 54: optical lens 56: slit plate 55: Light-receiving lens 57: Photo interrupter 58: Scanning angle detector 59: Hollow axis L1: Light in the first direction L2: Light in the second direction 70: Traveling part controller 71: Command signal 72: Traveling part controller 73: Chuck mechanism control unit 74: signal line 75: communication unit 80: control circuit 81: distance calculation unit 82: identification unit 83: correction calculation unit 84: light emission control unit

Claims (4)

Detected from the scanning unit that scans the modulated measurement light in a plane at the front part of the transport carriage traveling along the track, and the time delay between the measurement light scanned by the scanning unit and the reflected light from the detection object A distance measuring device including a distance calculation unit for calculating a distance to an object is disposed, and the transport carriage is based on reflected light from a retroreflective member disposed at the rear of the transport carriage traveling forward by the distance measuring apparatus. A distance measuring device for detecting a distance between vehicles,
The retroreflective member is composed of a micro prism type retroreflective member,
In the distance measuring device, a light source for measuring light composed of a laser diode that emits light in a single mode and a light receiving unit that receives reflected light are arranged opposite to each other on an optical axis, and the light from the light source is directed to a detection object. A first mirror that reflects light, a second mirror that reflects reflected light from the detection object toward the light receiving unit, a scanning unit that includes a rotation mechanism that rotates about the optical axis, and the first mirror A first polarizing element that is polarized in a first direction provided in an optical path that is reflected from the mirror toward the detection object, and a second that is different from the first direction provided in the optical path of the reflected light incident on the second mirror from the detection object. A second polarizing element that is polarized in the direction,
At least one of a plurality of scanning angles of the measurement light scanned by the scanning unit, a distance corresponding to each scanning angle calculated by the distance calculating unit, and an intensity of reflected light corresponding to each scanning angle. A distance measuring device comprising an identification unit for identifying whether or not the reflected light is from the retroreflective member based on two correlations. The distance according to claim 1, further comprising a correction calculation unit that corrects the intensity of the reflected light received by the light receiving unit based on an attenuation characteristic of the measurement light output from the first polarizing element according to a scanning angle. measuring device. The identification unit determines the continuity based on the correlation obtained for the measurement light scanned by the scanning unit and the correlation obtained for the measurement light previously scanned by the scanning unit. The distance measuring device according to claim 1 , wherein the distance measuring device identifies whether it is reflected light from the retroreflective member by evaluating. The transport carriage is configured by a traveling unit that travels along the track, and an article accommodating unit that is supported by the traveling unit, and the track supports a traveling wheel provided in the traveling unit and the support unit. and is connected, is constituted by a cover member surrounding the traveling portion, the distance measuring device and the retroreflection member, said claims 1 disposed on the traveling unit to be positioned inside the orbit of 3 The distance measuring device according to any one of the above.

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