JP2009029529A5 - - Google Patents

Description

Transport cart and optical distance measuring device

  The present invention is a transport carriage incorporating a lifting mechanism that moves up and down along a predetermined lifting path, which includes a chuck mechanism that self-travels along a traveling rail installed in an upper space and grips an object to be transported, And a distance measuring device.

  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. The above-described transport cart is used.

  As described in Patent Document 1 and Patent Document 2, in such a transport carriage, the transported object at the time of hanging is detected before it comes into contact with an obstacle such as a person or a carelessly placed object. In order to avoid contact accidents, the obstacle detection sensor that detects the presence or absence of obstacles by optically searching the lifting path between the hoisted carriage and the load port of each manufacturing equipment has fewer hoists than each manufacturing equipment. It is provided on the cart side.

  Such an obstacle detection sensor is configured to form a light film on the lifting path in order to expand the monitoring range in the traveling direction of the carriage with the hoist toward the lower side of the obstacle detection sensor. Specifically, while scanning a fan-shaped scan range centering on the obstacle detection sensor, the scan range is formed by dividing the scan range by two parallel virtual virtual planes. It was configured to be a film.

  And since the obstacle detection sensor mentioned above was attached to the trolley | bogie with a hoist, the said obstacle detection so that the obstacle in the raising / lowering path | route between the said obstacle detection sensor and a load port can be detected reliably. The light search range by the sensor is configured to be variably set according to the load port height of the manufacturing apparatus.

Japanese Patent No. 3371897 Japanese Patent No. 3375127 JP 2001-280284 A

  However, in the obstacle detection sensor attached to the conventional carriage described above, the detection resolution is different between the light search range close to the obstacle detection sensor and the light search range separated from the obstacle detection sensor, and the intensity of reflected light in the close light search range. However, since the scanning density is relatively high, even a small obstacle with a small reflectance can be detected reliably, but the intensity of the reflected light is weak and the scanning density is relatively low in the remote light search range. Therefore, there is a problem that only a sufficiently large obstacle can be detected.

  For example, an obstacle as large as a human finger can be detected in an adjacent light search range, but only an obstacle as high as a human arm can be detected in a remote light search range.

  For this reason, when the scanning speed is increased, the cost of parts for that purpose is increased, and there is a problem that the increase in the amount of detected light is also limited from the viewpoint of safety.

  In view of the above-described conventional problems, an object of the present invention is a transport cart that can accurately detect even an obstacle of a small size and avoid occurrence of an accident while avoiding an increase in parts cost. And providing an optical distance measuring device.

In order to achieve this object, the first characteristic configuration of the transport carriage according to the present invention, as described in claim 1 of the claims, is self-propelled along a traveling rail installed in the upper space, An optical distance measuring device for detecting the presence or absence of an obstacle on the elevating path, which is a conveying cart incorporating an elevating mechanism for elevating and lowering an elevating body having a chuck mechanism for gripping an object to be conveyed along a predetermined elevating path. Is attached to the lifting body, and the optical distance measuring device is configured so that a certain detection target space set between the lifting body and the mounting surface moves as the lifting body moves up and down. The obstacle search distance is set to be shorter than the distance between the optical distance measuring device and the placing surface of the transport object.

According to the above-described configuration, even when the search distance of the obstacle by the optical distance measuring device is set to a distance shorter than the distance between the optical distance measuring device and the placing surface of the object to be transported, along with the descent operation of the lifting body Since the optical distance measuring device attached to the lifting body is similarly lowered, even if the obstacle is small , there is a possibility of hindering the lifting operation by searching for the short distance. Since the search distance is set to a short distance, an obstacle can be sufficiently detected without setting the light source intensity of the optical distance measuring device to a very strong value.

  In the second feature configuration, as described in claim 2, in addition to the first feature configuration described above, the optical distance measuring device transmits measurement light output from a single light source on the lift path. A scanning unit that scans toward the measurement target space and a single light receiving unit that detects reflected light from an obstacle existing in the measurement target space, and based on the reflected light detected by the light receiving unit It is in the point comprised by the scanning optical distance measuring device which measures the distance to an obstruction.

  According to the above configuration, since the search distance is set to a short distance, the distance to the obstacle can be measured with sufficient accuracy without increasing the scanning speed of the measurement light.

  In the third feature configuration, as described in claim 3, in addition to the first feature configuration described above, the optical distance measuring device irradiates measurement light toward the measurement target space on the lift path. A sensor unit comprising a light source and a light receiving unit for detecting reflected light from an obstacle present in the measurement target space is arranged in a horizontal direction at a predetermined interval, and this corresponds to when each light source is scanned in a predetermined order by the scanning unit. A scanning optical distance measuring device that measures the distance to the obstacle based on the reflected light detected by the light receiving unit.

  According to the above-described configuration, even if a mechanism for optically scanning the measurement light from one light source is not provided, each light source is scanned in a predetermined order by the scanning unit, so that the measurement light emitted from the adjacent light source is used. Scanning can be performed so that stray light is not detected by other light receiving units, and an obstacle can be sufficiently detected without setting the intensity of the light source to a very high value, as described above.

  In the fourth feature configuration, as described in claim 4, in addition to any of the first to third feature configurations described above, the optical distance measuring device includes a measuring beam scanned by the scanning unit. The irradiation direction is attached to the outer frame of the elevating body in an inclined posture in which it is inclined to the outside of the elevating body from the vertical direction.

  According to the above-described configuration, the placement surface of the conveyance object can be removed from the measurement target space on the lifting path by the optical distance measuring device, and the placement surface is removed from the obstacle detected by the optical distance measuring device. This eliminates the need for complicated calculation processing.

The optical distance measuring device according to the present invention is characterized in that, as described in claim 5, the object to be conveyed is conveyed via an elevating mechanism incorporated in a conveyance carriage that is self-propelled along a traveling rail installed in the upper space. An elevating body having a chuck mechanism for gripping is attached so as to be movable up and down, and is an optical distance measuring device that detects the presence or absence of an obstacle on the elevating path of the elevating body, and is attached to the elevating body, As the elevator moves up and down, an obstacle search distance is set between the optical distance measuring device and the transport object so that a certain detection target space set between the elevator and the placement surface moves. The distance is set to be shorter than the distance to the placement surface.

  As described above, according to the present invention, it is possible to accurately detect even an obstacle of a small size while avoiding an increase in parts cost, and to prevent an accident from occurring in advance. A distance measuring device can be provided.

  Embodiments of a transport carriage and an optical distance measuring device according to the present invention will be described.

  As shown in FIG. 1, in a semiconductor device manufacturing facility, various manufacturing apparatuses 10 (10a, 10b, 10c, 10d) and the like for sequentially performing a predetermined process on a semiconductor wafer disposed along a passage 13 are provided. A wafer carrier device in which a plurality of semiconductor wafers placed on a load port 11 provided in the manufacturing apparatus 10 are accommodated in order to automatically transport the semiconductor wafer 21 between the storage equipment and the manufacturing apparatus 10 A transport carriage 30 for transporting 20 is provided to be able to run.

  As shown in FIG. 2, the transport cart 30 holds the wafer carrier device 20 on a base 31 having a travel mechanism 32 that self-travels along a travel rail 12 installed in an upper space of the manufacturing apparatus 10. An elevating mechanism 33 is incorporated for elevating and lowering an elevating body 35 provided with a chuck mechanism 36 for performing along a predetermined elevating path.

  The elevating mechanism 33 includes an elevating body 35, a plurality of belts 34 having one end fixed to a predetermined portion of the upper surface of the elevating body 35, and a winding shaft having the other end fixed to the base 31. And a lifting motor (not shown) that rotationally drives the belt 34. The driving of the lifting motor causes the belt 34 to be wound or unwound, and the lifting body 35 is configured to be movable up and down. The belt 34 incorporates a power supply line from the base 31 to the lifting body 35.

  The chuck mechanism 36 includes a pair of claws 37 for gripping the gripped portion 22 on the upper surface of the wafer carrier device 20, and drives a gripping solenoid or motor 81 (not shown) provided in the lift 34. Thus, the wafer carrier device 20 is configured to be held or released by the claw 37 being in the holding posture 37a or the opening posture 37b.

  As shown in FIG. 3, at the center of the side surface on the passage 13 side of the outer cover of the lifting body 35, the obstacle 61 on the lifting path of the wafer carrier device 20 held by the lifting body 35 and the lifting body 35. An optical distance measuring device 40 for detecting the presence or absence of is attached.

  The search distance La of the obstacle 61 by the optical distance measuring device 40 is set to a distance (for example, 1 m) shorter than the distance Lb (for example, 3 m) between the optical distance measuring device 40 and the load port 11, and the measurement target space 60 Is set in a fan-shaped shape having a central angle of 90 degrees around the optical distance measuring device 40 and a radius of 1 m.

  The optical distance measuring device 40 measures the distance to the obstacle 61 based on the reflected light reflected by the obstacle 61 from the single light source, and the search distance is set to a short distance. Therefore, the obstacle 61 can be detected with sufficient accuracy without increasing the scanning speed of the measurement light. Details will be described below. The following optical distance measuring device is only an example, and the distance measuring device used in the present invention is not limited to such a configuration.

  FIG. 4 is a schematic longitudinal sectional view showing the overall configuration of the optical distance measuring device 40. As shown in the figure, the optical distance measuring device 40 includes a housing 42 and a light projecting unit 43, a scanning unit 44, and a light receiving unit 45 as main components inside the housing 42. .

  The housing 42 has a shape in which two cylinders having different diameters overlap each other in the vertical direction in FIG. 4 via a stepped portion 42a2 and are closed at the top and bottom, and from the entire circumference of the peripheral wall portion 42a including the stepped portion 42a2. A translucent window 42a1 having a certain width in the vertical direction is formed across the side wall (shown on the right side wall in FIG. 4) excluding a part, and a light projecting portion to be described later is formed through the translucent window 42a1. The measurement light output from 43 and the reflected light that is reflected by the obstacle 61 and reaches the light receiving unit 45 can be transmitted and received. Leakage that allows measurement light to be detected by the light receiving unit 45 through the translucent window 42a1 by forming the stepped portion 42a2 in the translucent window 42a1 at substantially the same surface position as a top plate 48b described later. It is comprised so that light can be attenuated effectively.

  In addition, the portion of the housing 42 other than the light transmitting window 42a1 is composed of a light absorbing wall that is covered with a light absorbing member such as a dark curtain having a concavo-convex surface to completely block light and prevent reflection. Yes.

  The light projecting unit 43 includes, for example, a light emitting element such as a light emitting diode or a semiconductor laser, and a drive circuit for the light emitting element, and the light emitting element is arranged to output measurement light downward in the drawing. An optical lens 47 that makes the beam diameter of light constant is disposed on the light incident optical path L1 through which the measurement light output downward from the light projecting unit 43 passes.

  The scanning unit 44 scans the measurement light output from the light projecting unit 43 to the external measurement target space 60 through the light transmission window 42 a 1 of the housing 42, and exists in the rotating body 48 and the measurement target space 60. The reflection member 49 guides the reflected light from the obstacle 61 to the light receiving unit 45, and the motor 51 as a rotation mechanism.

  The rotating body 48 includes a cylindrical peripheral wall portion 48a and a top plate portion 48b that closes the upper end of the peripheral wall portion 48a. The lower end portion of the peripheral wall portion 48 a is reduced in diameter, and a hollow shaft 53 is inserted into the inner peripheral surface thereof via a bearing 52, and is rotatably supported by the hollow shaft 53.

  The motor 51 that rotationally drives the rotating body 48 includes a coil 51a on the stator side and a magnet 51b on the rotor side, and the magnet 51b is attached to the outer peripheral surface of the lower end portion of the peripheral wall portion 48a of the rotating body 48. The rotating body 48 is configured to rotate the reflection member 49 around a predetermined rotation axis by the interaction with the coil 51a.

  The light projecting unit 43 and the scanning unit 44 are arranged so that the rotation axis of the scanning unit 44 and the optical axis of the measurement light output from the light projecting unit 43 are parallel, and the light receiving unit 45 is arranged on the rotation axis. Has been. Specifically, the rotational axis of the scanning unit 44 is set at a position separated by a predetermined distance x from the optical axis of the light incident light path L1 in the reflecting member 49, as indicated by a broken line in FIG. That is, the reflection member 49 is configured to rotate in a circle around a predetermined rotation axis.

  The reflecting member 49 is disposed between the light projecting unit 43 and the light receiving unit 45 arranged to face each other, and the light projecting as the first reflecting member 49 a that propagates the measurement light output from the light projecting unit 3 to the measurement target space 60. The mirror and a pair of light receiving mirrors as the second reflecting member 49b that guides the reflected light from the obstacle to the light receiving unit 45 are configured.

  A first reflecting member 49a and a second reflecting member 49b are attached to the upper and lower surfaces of the top plate portion 48b of the rotating body 48 at a predetermined distance from the rotation axis in an inclined posture, and are emitted from the light projecting unit 3. The measured light is incident on the first reflecting member 49a through the light incident light path L1, then reflected and guided to the horizontal light projecting and outgoing light path L2, and the measurement target space formed outside the housing 42. Reflected light from an object that exists in the scanning region 60, that is, the obstacle 61, passes through the opening 48a1 formed in a part of the peripheral wall 48a of the rotator 48, and is received by the light receiving incident light path L3. After entering the reflecting member 49b, it is reflected and guided to the light receiving and emitting optical path L4. A light receiving lens 54 is mounted on the light receiving and emitting light path L4 so that the reflected light from the object is focused by the light receiving unit 45.

  In addition, the measurement light emitted from the light projecting unit 43 is guided from the upper surface to the lower surface of the top plate portion 48b of the rotating body 48 at a position symmetrical to the optical axis of the measuring light and the rotation axis of the rotating body 48. When the reference light hole 50 is provided and the rotator 48 rotates and the reference light hole 50 is located directly below the light projecting unit 43, a part of the measurement light is emitted as the reference light to the outside of the apparatus. Without passing through, the reference light hole 50 is guided to the light receiving unit 45.

  The first reflecting member 49a and the second reflecting member 49b are inclined at 45 degrees with respect to the rotation axis of the rotating body 48, and the light projecting and emitting light path L2 and the light receiving and emitting light path L3 are projected. Each has an optical axis orthogonal to the optical axis of the incident optical path L1 (the optical axis of the received incident optical path L4), and is set to be parallel to each other. As a result, it is possible to take in reflected light that is irradiated and reflected on the object through the light projecting and exiting optical path L2 from the light receiving incident optical path L3. Furthermore, a scanning angle detector 55 that detects the scanning angle of the rotator 48 includes a slit plate 55a having an optical slit fixed to the outer peripheral surface of the rotator 48, and a photo arranged on the rotation path of the slit plate 55a. It is comprised from the interrupter 55b.

  The light receiving unit 45 is configured to detect reflected light from the obstacle 61, and includes a light receiving element such as an avalanche photodiode and an amplification circuit that amplifies the photoelectrically converted signal, and rotates. In a state of being housed inside the body 48, it is disposed so as to face the light projecting unit 43. More specifically, the light receiving unit 45 is disposed on the upper end surface of the hollow shaft 53 that supports the rotating body 48, and always maintains a stationary state regardless of the rotating operation of the rotating body 48 by the motor 51. ing. Although not shown, the output signal from the light receiving unit 45 is connected to a signal processing circuit described later by a signal line inserted into the internal space of the hollow shaft 53.

  When the rotator 48 is rotated, the measurement light output from the light projecting unit 43 scans the measurement target space 60 having a fan shape centered on the rotation axis of the rotator 8.

  However, when the reflecting member 49 is rotated by the rotating body 48, the measurement light output from the specific rotation position, that is, the scanning unit 44 is output toward the light absorbing wall of the housing 42 off the light transmitting window 42a1. If the scanning unit 44 is located at a position where the reference light hole 10 is located directly below the light projecting unit 45 and the optical lens 47, a part of the measurement light output from the light projecting unit 43 Is guided to the light receiving unit 45 through the reference light hole 50 as reference light. At this time, a part of the measurement light incident on the first reflecting member 49a is absorbed by the light absorption wall of the housing 42 and therefore is not emitted outside the apparatus. The specific rotation position is preferably a position at which the measurement light output from the scanning unit 44 is directed to the opposite side with respect to the horizontal center position of the translucent window 42a1.

  The formation range of the light transmission window 42a1 through which the measurement light is scanned to the outside is set to an angular range of 120 to 180 degrees around the optical axis of the light incident light path L1.

  That is, the light projecting unit 43 and the scanning unit 44 are arranged so that the rotation axis of the scanning unit 44 and the optical axis of the measurement light output from the light projecting unit 43 are parallel to each other. Part of the measurement light output from the light projecting unit 43 is configured to be guided to the light receiving unit 43 without passing through the reflecting member 49 as reference light.

  As shown in FIG. 5A, the optical distance measuring device 40 uses the reference light to the light receiving unit 45 after the measurement light S2 is emitted from the light projecting unit 43 when the scanning unit 44 is located at the specific rotation position. The time t1 until the light S3 arrives is calculated, and when the scanning unit 44 is located at a position other than the specific rotation position, the measurement light S2 is emitted from the light projecting unit 43 and then the obstacle 61 A time t2 until the reflected light S4 reaches the light receiving unit 45 is calculated.

  The calculated time t1 is the time when only the light ranging device 40 is passed through the light projecting unit 3 to the light receiving unit 45, while the calculated time t2 is the inside of the light ranging device 40. Since the time is from the light projecting unit 43 to the light receiving unit 45 through the outside, the light projecting unit 43 is transmitted only through the outside of the apparatus by performing an operation of subtracting the time t1 from the calculated time t2. It is possible to calculate the time from the light receiving unit 45 to the light receiving unit 45, that is, the time in which the influence of fluctuations of unstable elements inside the optical distance measuring device 40 is accurately reduced.

  The details of the calculation of the time described in FIG. 5A and the calculation of the distance between the optical distance measuring device 40 and the obstacle 61 based on the time will be described below.

  In the optical distance measuring device 40 described above, a correction value calculation unit 74 that calculates a correction value for correcting the distance to the obstacle based on the reference light detected by the light receiving unit 45 in synchronization with the output timing of the measurement light; The signal processing circuit 70 provided with the calculating part 75 which calculates the distance to the obstruction 61 based on the reflected light detected by the light-receiving part 45 in synchronization with the output timing of the measurement light and the correction value will be described.

  As shown in FIG. 6, 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 55, and the scanning. When the unit 44 is not at the specific rotation position, the measurement light detection unit 72 detects the electrical signal output from the light receiving unit 45 as a measurement light signal, and when the scanning unit 44 is at the specific rotation position, the light is output from the light reception unit 45. A reference light detection unit 73 that detects the detected electrical signal as a reference light signal, and correction for the search distance between the optical distance measuring device 40 and the obstacle 61 based on the reference light signal detected by the reference light detection unit 73 A correction value calculation unit 74 that calculates a value, and a calculation that calculates a search distance based on the measurement light signal detected by the measurement light detection unit 72 and calculates a final search distance based on the search distance and the correction value Part 5, the angle signal and calculates the position of the last search distance from the obstacle, is constituted by a signal control unit 76 to determine whether it is within range of the measurement target space 60.

  In order to drive the optical distance measuring device 40, a lifting / lowering operation start signal of the lifting / lowering body 35 is output from the lifting / lowering body-side control unit 80 to the signal control unit 76, and the motor 51 is driven by the signal control unit 76 at a predetermined speed. A pulse signal output from the scanning angle detection unit 55 as the motor 51 is driven to rotate is input to the light emission control unit 71. Based on the pulse signal, the light emission control unit 71 determines the output direction of the measurement light from the scanning unit 44. Be grasped. In addition, since the slit interval of the slit plate 55a constituting the scanning angle detector 55 is formed so as to be different from the other reference position of the rotary body set in advance, the reference position is detected based on the waveform of the pulse signal. The rotation angle from the reference position is calculated by counting the number of pulses from the reference position.

  As shown in FIG. 5B, the measurement timing signal is input to the light emission control unit 71 from the signal 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 55. Then, 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 43 at a predetermined timing based on the measurement timing signal.

  In the light projecting unit 43 that has received the light emission drive signal S1, the modulation circuit 81 modulates the laser light or LED light into pulsed measurement light, and a drive circuit (not shown) causes the light emitting element 82 to synchronize with the light emission drive signal S1. When driven, the light emitting element 82 emits the measuring light S2 to the outside of the apparatus. That is, the light emission intensity of the measurement light S2 is controlled by the duty ratio of the light emission drive signal S1 and the drive current of the light emitting element 82, and the light emitting element is intermittently driven at the same cycle as the measurement timing signal output at a predetermined cycle.

  When the scanning unit 44 is not located at the specific rotation position, the reflected light S4 reflected by the obstacle in the output measurement light S2a is detected by the light receiving element 83, and the amplification circuit 84 performs photoelectric conversion of the reflected light S4. Then, the converted electric signal is amplified to a level that allows signal analysis and output.

The measurement light detector 72 detects the electrical signal as the reflected signal S5a and outputs the detected signal to the correction value calculator 74. In addition, when the scanning part 44 is located in a specific rotation position, the measurement light detection part 72 is comprised so that a signal may not be detected.

  On the other hand, when the scanning unit 44 is located at the specific rotation position, a part of the output measurement light S2b is detected by the light receiving unit 45 through the above-described reference optical path without being emitted outside the apparatus as the reference light S3. Then, the photoelectric conversion of the reference light S3 is performed in the amplifier circuit 84, 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 calculation unit 75. When the scanning unit 44 is not at the specific rotation position, the reference light detection unit 73 is configured not to detect a signal.

The distance L from the light source to the obstacle is calculated based on the following [Equation 1] from the flight time Δt of light and the speed of light C.

  The correction value calculation unit 74 calculates a time difference t1 between the light emission drive signal S1 corresponding to the measurement light S2b and the reference signal S5b, and calculates a correction value ΔL for the search distance between the optical distance measuring device 40 and the obstacle 61 from the time difference t1. Calculate from [Equation 1]. In calculating the correction value ΔL, the time difference t1 is substituted into T in [Equation 1] to calculate the correction value ΔL as L.

  The computing unit 75 calculates the time difference t2 between the light emission drive signal S1 and the reflected signal S5a corresponding to the measurement light S2a, and calculates the search distance L1 from [Equation 1] from the time difference t2. In calculating the search distance L1, the search distance L1 as L is calculated by substituting the time difference t2 into Δt in [Equation 1].

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

  The signal control unit 76 calculates the position of the obstacle 61 from the angle signal and the final search distance. That is, the direction of the obstacle 61 relative to the optical distance measuring device 40 is calculated from the angle signal, and the distance of the obstacle 61 from the optical distance measuring device 40 is calculated from the final search distance.

  The signal processing unit 76 stores the data of the position of the obstacle 61 in a memory provided inside the signal processing unit 76 and determines whether or not the measurement target space 60 is within the range.

  Next, each functional block of the transport carriage 30 will be described. As shown in FIG. 7, the elevating body 35 includes a gripping motor 81 for bringing the pawl 37 of the chuck mechanism 36 into the gripping posture 37a or the opening posture 37b, and the pawl 37 of the chuck mechanism 36 as a wafer carrier device. Signal processing provided with various lifting body side sensors 82 for detecting that the hand 20 has been grasped or released, and a signal control unit 76 for processing the detected signal when the obstacle 61 is detected by the optical distance measuring device 40. In order to communicate with the circuit 70 and the base 31, a lifting / lowering body side transmission / reception unit 83 and a lifting / lowering body side control unit 80 that performs overall control of the respective parts included in the lifting body 35 are provided.

  The base 31 includes a lifting motor 91 for winding or unwinding the belt 34 for moving the lifting body 35 up and down, and the load port 11 of the manufacturing apparatus 10 in which the base 31 is designated by a conveyance instruction unit (not shown). Various base side sensors 92 for detecting the above and the base side transmission / reception unit 93 for communicating with the lifting body 35 and for driving the traveling mechanism 32 for traveling on the traveling rail 12 And a travel motor 94.

  The elevator-side transmitting / receiving unit 83 and the base-side transmitting / receiving unit 93 are configured by an optical communication unit including a pair of light emitting elements and a light receiving element, respectively, and signals to be transmitted / received are configured by 8-bit serial data, When the obstacle 61 is detected within the measurement target space 60, the elevator body side control unit 80 controls the obstacle detection data so as to transmit the obstacle detection data from the elevator body side transmission unit 83a to the base side reception unit 93b. Yes.

  An operation in which the elevating body 35 of the transport carriage 30 having the above-described configuration moves up and down the wafer carrier device 20 and an operation in the case where the obstacle 61 exists on the elevating path will be described.

  FIG. 8 is a schematic side view showing the positional relationship between the transport carriage 30, the lifting body 35, and the wafer carrier device 20.

  As shown in FIG. 8A, first, in order to transfer the wafer carrier device 20 placed on the load port 11 of the manufacturing apparatus 10, the transfer carriage 30 stops on the load port 11 instructed by the transfer instruction unit. To do. The optical distance measuring device 40 provided on the lifting body 35 of the transport carriage 30 starts scanning in order to detect an obstacle on the lifting path of the lifting body 35. Next, the base side controller 90 drives the lifting motor 91 to feed out the belt 34 and lower the lifting body 35.

  When the elevating body 35 moves up and down, the measurement light emitted from the optical distance measuring device 40 is reflected by the load port 11, and the optical distance measuring device 40 detects the reflected light. However, if the distance from the optical distance measuring device 40 calculated as described above is equal to or greater than a predetermined distance, that is, not in the fan-shaped measurement target space 60 below the optical distance measuring device 40, it is not detected as an obstacle. Therefore, the load port 11 is not detected as an obstacle that affects the lifting operation of the lifting body 35, and the lifting body 35 is further lowered.

  As shown in FIG. 8 (b), since the obstacle is not detected in the measurement target space 60 by the optical distance measuring device 40 even if the elevating body 35 is further lowered, the elevating body 35 continues to descend.

  As shown in FIG. 8 (c), when the elevating body 35 is lowered to a predetermined position near the wafer carrier device 20, the elevating body control unit 80 drives the gripping motor 81 and the nail provided in the chuck mechanism 36. 37 is switched from the open posture to the gripping posture to grip the gripped portion 22 of the wafer carrier device 20.

  Note that the measurement target space 60 is set in advance corresponding to the distance to the load port 11 corresponding to the type of manufacturing apparatus input to the memory inside the signal processing unit 76 in advance. When the distance between the traveling rail 12 and the load port 11 differs depending on the type of manufacturing apparatus, the measurement target space 60 is set to the optimum measurement target space according to the manufacturing apparatus by changing the search distance and the search angle. The

  In addition, even if the data of the distance from the traveling rail corresponding to the type of the manufacturing apparatus to the load port 11 is not input to the memory inside the signal processing unit 76 in advance, the transport cart 30 receives data from the transport instruction unit for each manufacturing apparatus 10. You may comprise so that it may obtain.

  As shown in FIG. 8D, when the lifting body 35 grips the wafer carrier device 20, the base side control unit 90 drives the lifting motor to wind up the belt 34. As shown in FIG. 8E, when the elevating body 35 and the wafer carrier device 20 are taken into the base 31, the optical distance measuring device 40 stops scanning, and the transport carriage 30 follows the instructions of the transport instruction section. The wafer carrier device 20 is transferred to the manufacturing apparatus.

  An operation of the transport carriage 30 when the optical distance measuring device 40 detects an obstacle 61 in the measurement target space 60 on the lifting path in the lifting operation of the lifting body 35 described above will be described.

  As shown in FIG. 8 (f), when the obstacle 61 exists on the lifting path, but the distance from the lifting body 35 is still sufficiently separated, that is, the obstacle 61 is positioned in the measurement target space 60. If not, the lowering operation of the lifting body 35 is continued because the lowering operation of the lifting body 35 is not affected. However, as shown in FIG. 8G, when the lifting body 35 is further lowered and the obstacle 61 is positioned in the measurement target space 60, the lifting body side control unit 80 provided in the lifting body 35 transmits the lifting body side transmission. When the obstacle detection data is transmitted from the unit 83a and the base side receiving unit 93b receives the obstacle detection data, the base side control unit 90 stops the lifting and lowering motor 91, and the feeding of the belt 34 is stopped. The lowering operation of the elevating body 35 stops.

  When the obstacle 61 is detected in this way, the operation of the elevating body 35 is stopped for the safety of the surroundings. At this time, an alarm is notified or the operation of the elevating body 35 is automatically performed when the obstacle 61 is removed. Control such as restarting is appropriately determined according to the use of the transport carriage 30.

  As described above, even if the measurement target space 60 of the obstacle 61 by the optical distance measuring device 40 is set to a distance shorter than the distance between the optical distance measuring device 40 and the load port 11 which is the mounting surface of the wafer carrier device 20. Since the optical distance measuring device 40 attached to the lifting / lowering body 35 is similarly lowered along with the lowering operation of the lifting / lowering body 35, an obstacle 61 that may hinder the lifting / lowering operation if the predetermined short distance is searched. Can be reliably detected. And since the search distance is set to a short distance, even when the surface reflectance of the obstacle 61 is small, the obstacle is sufficiently detected without setting the light source intensity of the optical distance measuring device 40 to a very strong value. It can be done.

  As shown in FIG. 9A, the case where the optical distance measuring device 40a is provided in the base 31 is compared with the case where the optical distance measuring device 40b is provided in the lifting body 35 as shown in FIG. 9B. Then, when both the optical distance measuring devices 40a and 40b have the same configuration and the angular resolution is equal to θ, if the maximum search distance is shortened from 3L to L, the size of the detectable obstacle 61 in the scanning direction is changed from 3d to d. And the detection resolution is improved.

  For example, only an obstacle about the human arm can be detected in the separated light search range, but an obstacle about the human finger can be detected in the close light search range.

  As described above, when the optical distance measuring device 40a is provided on the base 31 of the transport carriage 30 and the measurement target space is scanned, it is necessary to increase the scanning speed, resulting in an increase in parts cost and safety. From the standpoint of performance, there is a limit to the increase in the amount of detected light. However, if the elevating body 35 includes the optical distance measuring device 40b, an obstacle 61 having a slight size can be used while avoiding an increase in parts cost. Even if it exists, the conveyance trolley | bogie 30 and the optical ranging device 40 which can be detected accurately and can avoid the occurrence of an accident can be provided.

  In the above-described embodiment, as an example of the optical distance measuring device 40, in order to correct the search distance, the rotation axis of the scanning unit 44 is separated from the optical axis of the light incident light path L1 in the reflecting member 49 by a predetermined distance x. The measurement light emitted from the light projecting unit 43 is set to a position and symmetrical to the optical axis of the measurement light and the rotation axis of the rotator 48 from the upper surface to the lower surface of the top plate portion 48b of the rotator 48. Although the configuration in which the reference light hole 50 for guiding is provided has been described, the reference optical path for correction is not limited to such a configuration.

In the above-described embodiment, the optical distance measuring device 40 outputs measurement light obtained by modulating laser light or LED light into pulse light, and based on the time difference between the reflected signal returned by the obstacle and the measurement light, Although the configuration for calculating the distance has been described, as a distance measuring method of the optical distance measuring device, a measurement signal obtained by modulating laser light or LED light with a sine wave is output and reflected by the measurement object, The configuration may be such that the distance is calculated based on the phase difference of the measurement light. The distance L from the light source to the obstacle is calculated on the basis of the following [Equation 2] based on the measured phase difference, C the speed of light, and F the modulation frequency.

  In this case, the light projecting unit 43 that has received the light emission drive signal from the light emission control unit 71 emits measurement light in which the laser light or the LED light is modulated by a sine wave in the modulation circuit 31.

  In the above-described embodiment, as shown in FIG. 10A, the optical distance measuring device 40 is installed at the center of the side surface on the passage side of the lifting body 35 so that the distance measuring direction is vertically downward in the figure. As described above, in the optical distance measuring device 40, the irradiation direction of the measurement light scanned by the scanning unit 44 is from the vertical direction to the passage side direction of the elevator 35, that is, the load port 11 in the measurement target space 60. The distance measuring direction may be attached to the side surface of the elevating body 35 on the passage side so that the distance measurement direction is inclined at an angle α with respect to the vertical downward direction. Thereby, as shown in FIG. 10B, the load port 11 on which the wafer carrier device 20 is placed can be removed from the measurement target space 601 on the lifting path by the optical distance measuring device 401, and the optical distance measuring device. No longer need to be subjected to complicated calculation processing to prevent erroneous detection as an obstacle when the reflected light from the load port 11 is detected as in the case where the distance measuring direction is vertically downward.

  11, the optical distance measuring device 401 is mounted on the side of the passage 13 of the lifting / lowering body 35 in such a manner that the distance measuring direction is inclined at an angle α with respect to the vertically downward direction in the figure as described above. The raising / lowering operation | movement to which the raising / lowering body 351 raises / lowers the wafer carrier apparatus 20 is shown. The positional relationship among the transport carriage 301, the lifting body 351, and the wafer carrier device 20 is the same as that shown in FIG. As shown in FIG. 11 (g), by providing the optical distance measuring device 401 in an inclined posture, the distance measuring direction is inclined at an angle α with respect to the vertical downward direction. It can be detected.

  In the above-described embodiment, the case where the measurement target space 60 is defined as a fan having a central angle of 90 degrees and a radius of 1 m has been described. However, the shape of the measurement target space 60 is not limited to this, and the central angle and the radius Can be set as appropriate. For example, the shape is arbitrarily set as necessary, such as defining a fan shape with a central angle of 120 degrees and a radius of 0.5 m.

  Needless to say, the measurement target space 60 is not limited to a fan shape and can be set to an arbitrary shape as necessary, such as a triangle or an arbitrary polygon. By setting the search distance to be different for each predetermined scanning angle, the measurement target space can be set to an arbitrary shape. For example, as illustrated in FIG. 3D, the measurement target space 60 is set to be substantially pentagonal downward from the optical distance measuring device 40, so that the lower end of the measurement target space 60 is the mounting surface of the load port 11. It can also be made parallel to.

  Another embodiment of the present invention will be described below.

  In the above-described embodiment, the optical distance measuring device 40 measures the distance to the obstacle 61 based on the reflected light reflected by the obstacle 61 from the measurement light output from the single light source, and the search distance is short. Although the case where the distance to the obstacle 61 can be measured with sufficient accuracy without increasing the scanning speed of the measurement light has been described, as shown in FIG. In addition, the optical distance measuring device includes a light source that irradiates the measurement light toward the measurement target space 602 on the lifting path and a light receiving unit that detects reflected light from the obstacle 61 existing in the measurement target space 602. The sensor units are arranged horizontally at predetermined intervals, and the distance to the obstacle 61 is measured based on the reflected light detected by the corresponding light receiving unit when the light sources are scanned in a predetermined order by the scanning unit. Light measurement May be each other consists of device 402.

  FIG. 13 is a functional block diagram of the transport carriage 302 including the optical distance measuring device 402. Note that description of blocks having the same functions as the functional blocks of the optical distance measuring device 40 shown in FIG. 7 is omitted.

  Here, in the optical distance measuring device 402, the signal processing unit 762 provided in the signal processing circuit 702 transmits a switching signal to each sensor unit, so that the scanning unit scans each light source in a predetermined order so that the mutual stray light does not interfere with each other. By doing so, it scans so that the stray light by the measurement light irradiated from the adjacent light source may not be detected by another light-receiving part.

  Specifically, the odd-numbered and even-numbered sensor units from the left end of the optical distance measuring device 402 in FIG. 12 are alternately scanned, and the first to fifth from the left end are scanned. A configuration may be adopted in which groups from the tenth to the tenth are scanned in order from the sensor unit at the left end of each group. This may be appropriately selected so that stray light does not interfere with each other according to the number of sensor units constituting the optical distance measuring device 402 and the interval between the sensor units.

  Also in the case of the optical distance measuring device 402, as in the case of the optical distance measuring device 40 described above, the optical distance measuring device 402 and the wafer carrier device 20 pass through the measurement target space 602 of the obstacle 61 by the optical distance measuring device 402. Even if the distance is set shorter than the distance from the load port 11 which is the mounting surface, the optical distance measuring device 402 attached to the lifting / lowering body 35 is similarly lowered along with the lowering operation of the lifting / lowering body 35. By searching for the predetermined short distance, it is possible to reliably detect an obstacle 61 that may interfere with the lifting operation. Since the search distance is set to a short distance, even if the surface reflectance of the obstacle 61 is small, the obstacle can be detected sufficiently without setting the light source intensity of the optical distance measuring device 402 to a very strong value. it can.

  That is, if the distance to the obstacle 61 is different, the detection resolution is different, and if the light quantity is the same, the reflected light intensity is weak in the separated light search range, and the scanning density is relatively small, so the reflectance is large. While only sufficiently large obstacles can be detected, the reflected light intensity is high in the close light search range, and the scanning density is relatively large, so even small obstacles with low reflectance can be reliably detected. Can be detected.

  Specifically, since the detection resolution is inversely proportional to the square of the distance, if the search distance is 1/3, the detection resolution is nine times and even an object with poor reflectance can be detected.

  Note that the optical distance measuring device 402 also has an irradiation direction of the measuring light scanned by the scanning unit in the direction from the vertical direction to the passage side of the lifting body 35 in the same manner as the optical distance measuring device 401 shown in FIG. In other words, the distance measuring direction may be attached to the side surface on the passage side of the elevating body 35 so that the distance measuring direction is inclined at a predetermined angle with respect to the vertical downward direction so that the load port 11 does not enter the measurement target space 602. As a result, the load port 11 on which the wafer carrier device 20 is placed can be removed from the measurement target space 602 on the up-and-down path by the optical distance measuring device 402 and is not detected by the optical distance measuring device 402, and the distance measuring direction is changed. When the reflected light from the load port 11 is detected as in the case of the vertically downward direction, it is not necessary to perform complicated calculation processing for not detecting the reflected light as an obstacle.

  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.

Schematic perspective view of manufacturing equipment, wafer carrier equipment, transport cart, etc. in semiconductor device manufacturing equipment Explanatory drawing of transfer cart and wafer carrier device (A) Plan view (b) Front view (c) Side view (d) Manufacturing apparatus, wafer carrier device, transport cart in another embodiment, explaining the positional relationship between the manufacturing device, wafer carrier device, transport cart, and measurement target space And front view explaining the positional relationship of the measurement object space Schematic cross section of optical distance measuring device (A) Explanatory view of time until reference light reaches the light receiving portion from the light projecting portion and time until reflected light from the obstacle reaches the light receiving portion (b) Explanatory view of the light emission drive signal Block diagram of optical distance measuring device and signal processing circuit Functional block diagram of transport cart (A) First side view (b) Second side view (c) Third side view (d) Fourth side view (e) Fifth side view (F) Sixth side view (g) Seventh side view Explanatory diagram of detection resolution depending on the position of the optical ranging device (A) Side view for explaining the distance measurement target space when the optical distance measuring device is installed so that the distance measuring direction is vertically downward (b) The distance measuring direction of the optical distance measuring device is vertically downward Side view for explaining the space to be measured when it is installed in an inclined posture so as to incline at an angle α with respect to the direction (A) 1st side view (b) 2nd side view (c) 3rd side view (d) 4th side view (e) 4th for demonstrating raising / lowering operation | movement of the raising / lowering body in another embodiment Fifth side view (f) Sixth side view (g) Seventh side view Explanatory drawing of the conveyance trolley in another embodiment Functional block diagram of the transport carriage in another embodiment

10: Manufacturing apparatus 11: Load port 12: Traveling rail 13: Passage 20: Wafer carrier device 21: Wafer 22: Grasping part 30: Transport cart 302: Transport cart 31: Base 32: Travel mechanism 33: Lifting mechanism 34 : Belt 35: Lifting body 36: Chuck mechanism 37: Claw 40: Optical distance measuring device 401: Optical distance measuring device 402: Optical distance measuring device 60: Measuring object space 601: Measuring object space 602: Measuring object space 61: Obstacle

Claims (5)

A carriage that incorporates an elevating mechanism that moves up and down along a predetermined elevating path along a predetermined elevating path, which is self-propelled along a traveling rail installed in an upper space and has a chuck mechanism that grips an object to be conveyed,
An optical distance measuring device that detects the presence or absence of an obstacle on the lifting path is attached to the lifting body, and is set between the lifting body and the mounting surface as the lifting body moves up and down. Conveyance in which the search distance of the obstacle by the optical distance measuring device is set to be shorter than the distance between the optical distance measuring device and the placement surface of the conveyance object so that a certain detection target space moves . Trolley.   The optical distance measuring device scans the measurement light output from a single light source toward the measurement target space on the lift path, and detects reflected light from an obstacle existing in the measurement target space. The transport carriage according to claim 1, comprising a single light receiving unit configured to measure a distance to the obstacle based on the reflected light detected by the light receiving unit.   A sensor unit comprising: a light source that irradiates measurement light toward the measurement target space on the lift path; and a light receiving unit that detects reflected light from an obstacle existing in the measurement target space. Scanning optical distance measurement that measures the distance to the obstacle based on the reflected light that is arranged in the horizontal direction at predetermined intervals and that is detected by the corresponding light receiving unit when each light source is scanned in a predetermined order by the scanning unit The conveyance cart according to claim 1, which is constituted by an apparatus.   The optical distance measuring device is attached to an outer frame of the lifting body in an inclined posture in which an irradiation direction of measurement light scanned by the scanning unit is inclined to the outside of the lifting body from a vertical direction. The conveyance trolley in any one of. An elevating body having a chuck mechanism for gripping an object to be conveyed via an elevating mechanism incorporated in a conveyance carriage that self-propels along a traveling rail installed in an upper space is attached to be movable up and down, and an elevating path of the elevating body An optical distance measuring device that detects the presence or absence of an obstacle above,
The obstacle search distance is set such that a fixed detection target space set between the lifting body and the mounting surface moves as the lifting body is lifted and lowered. An optical distance measuring device that is set to a distance shorter than a distance between the optical distance measuring device and a placement surface of the conveyance object.