JP2013002976A - Probe unit, circuit board inspection device and probe unit manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe unit which realizes miniaturization while suppressing increase in manufacturing cost and occurrence of failure.SOLUTION: A probe unit comprises: a plurality of probes 12; and a holding part 11 holding each probe 12. The holding part 11 is formed of a tabular body having insertion holes 11c. The probes 12 are formed of coated conductive wires 21 inserted into the insertion holes 11c in such a manner that tip parts 21c protrude from an underside 11a of the holding part 11, and are held by the holding part 11 through an elastic material 13 filled in the insertion holes 11c in a state of being movable along central axes A of the insertion holes 11c and also being insulated from the other coated conductive wires 21.

Description

  The present invention relates to a probe unit including a plurality of probes and a holding unit for holding each probe, a circuit board inspection apparatus including the probe unit, and a probe unit manufacturing method for manufacturing the probe unit.

  As a probe unit used for inspection of a circuit board or the like, a probe unit (vertical operation type probe card) disclosed in Japanese Patent Laid-Open No. 2000-292439 is known. The probe unit includes a plurality of probes having a buckled portion at the center, a substrate on which a wiring pattern that is in contact with a connection portion of each probe is formed via an anisotropic conductor, and a plurality of through holes. And a probe support member having the formed upper support substrate and lower support substrate. In this probe unit, each probe is fixed to the upper support substrate with an adhesive while being penetrated through the through hole of the upper support substrate and the through hole of the lower support substrate. In this probe unit, the arrangement of the probes is defined in accordance with the arrangement of the conductor patterns on the substrate to be probed, and each probe can be probed to each conductor pattern at a time.

Japanese Unexamined Patent Publication No. 2000-292439 (page 3, FIG. 1)

  However, the above probe unit has the following problems. That is, this probe unit has a complicated structure in which a probe having a buckling portion at the center is supported by a plurality of members (in the above example, an upper support substrate and a lower support substrate) so as to be buckled. . Further, in this probe unit, an electrode for inputting / outputting a signal (in the above example, a portion of the anisotropic conductor facing the probe) and a connecting portion of the probe are in contact when probing, and are separated when not probing. Due to the structure, there is a possibility that a failure such as a contact failure occurs at the electrical contact. On the other hand, along with the increase in the density of circuit boards, the miniaturization and narrowing of the conductor pattern have progressed, and in order to cope with this, miniaturization of the probe unit is required. However, since the conventional probe unit has a complicated structure as described above, it is difficult to reduce the size of the probe unit, and it is difficult to cope with the high density of the circuit board. Even if downsizing is possible, advanced processing technology is required for downsizing, resulting in an increase in the manufacturing cost of the probe unit. There is also a risk that failure such as poor contact may occur.

  The present invention has been made in view of such problems, and provides a probe unit, a circuit board inspection apparatus, and a probe unit manufacturing method capable of realizing downsizing while suppressing an increase in manufacturing cost and occurrence of failure. The main purpose.

  In order to achieve the above object, the probe unit according to claim 1 is a probe unit including a plurality of probes and a holding portion for holding the probes, and the holding portion has a plate-like body having an insertion hole. The probe is composed of a linear or rod-like conductor inserted into the insertion hole so that the tip portion protrudes from one surface of the holding portion, and along the central axis of the insertion hole. It is hold | maintained at the said holding | maintenance part via the elastic material with which the said insertion hole was filled with the state which was movable and insulated with respect to the said other conductor.

  According to a second aspect of the present invention, in the probe unit according to the first aspect, the probe is formed of a coated conductor.

  The probe unit according to claim 3 is the probe unit according to claim 1 or 2, wherein a plurality of the probes are inserted into one insertion hole.

  A probe unit according to a fourth aspect is the probe unit according to the third aspect, wherein the plurality of probes are inserted into the one insertion hole in a twisted state.

  Further, the circuit board inspection apparatus according to claim 5 inputs and outputs via the probe of the probe unit according to any one of claims 1 to 4 and the probe of the probe unit brought into contact with the circuit board as a probing object. And an inspection unit that performs an electrical inspection on the circuit board based on the electrical signal.

  The probe unit manufacturing method according to claim 6 is a probe unit manufacturing method for manufacturing a probe unit including a plurality of probes and a holding portion for holding each probe, and the plate-like body has an insertion hole. Forming the holding portion by forming, and inserting the conductor into the insertion hole so that the tip of a linear or rod-like conductor that functions as the probe protrudes from one surface of the holding portion, and the insertion hole The insertion hole is filled with the elastic material so that the electric conductor is held by the holding portion via the elastic material in a state where the electric conductor can be moved along the central axis of the electrode and insulated from the other electric conductor. The probe unit is manufactured.

  7. The probe unit according to claim 1 and the probe unit manufacturing method according to claim 6, wherein a holding portion is formed by forming an insertion hole in the plate-like body, and the tip portion of a linear or rod-like conductor that functions as a probe. Elastic material in the insertion hole so that the conductor is inserted into the insertion hole so that the protrusion protrudes from one surface of the holding part, and the conductor is held in the holding part via the elastic material so as to be movable along the central axis of the insertion hole. The probe unit is manufactured. That is, this probe unit is configured by a holding unit configured by a single plate-shaped body and a probe configured by a linear or rod-shaped conductor. For this reason, according to the probe unit and the probe unit manufacturing method, the number of types of components of the probe unit is smaller than that of a conventional probe unit of a type in which a pin-shaped probe is buckled by a plurality of members. Since the structure is simple, the manufacturing process can be simplified. As a result, the manufacturing cost can be sufficiently reduced. Therefore, according to the probe unit and the probe unit manufacturing method, the probe unit can be easily miniaturized corresponding to the high-density circuit board as the probing object, and the manufacturing cost can be reduced. Can be sufficiently reduced. Also, according to the probe unit and the probe unit manufacturing method, unlike the conventional configuration in which the contact and separation between the electrode for inputting and outputting signals and the connection portion of the probe are repeated every time probing is performed, such probing is performed. Since there is no portion where contact and separation are repeated each time, it is possible to reliably prevent the occurrence of a failure due to contact failure in that portion.

  According to the probe unit of the second aspect, since the probe is composed of the coated conductor, the coated conductor itself has an insulating property, so that each coated conductor is securely insulated from each other. It can be held by the holding part. In addition, by configuring the probe with a coated conductor, the coated conductor can be directly connected to an inspection unit or the like of the circuit board inspection apparatus. That is, the coated conductive wire as a probe can be used as it is as a lead wire for connection with an inspection unit or the like. For this reason, the manufacturing cost of the probe unit can be reduced because the connection between the conductor as the probe and the lead wire for connection is unnecessary compared to the configuration using the lead wire for connection separate from the conductor as the probe. Can be further reduced.

  According to the probe unit according to claim 3, since a plurality of probes are inserted into one insertion hole, the interval between the probes is compared with a configuration in which one probe is inserted into one insertion hole. (Pitch) can be narrowed. For this reason, according to this probe unit, it is possible to further reduce the size of the probe unit corresponding to a higher-density circuit board while sufficiently reducing the manufacturing cost.

  According to the probe unit of the fourth aspect, since the plurality of twisted probes are inserted into one insertion hole, the interval (pitch) between the plurality of probes inserted into one insertion hole is further increased. It can be narrowed. For this reason, according to this probe unit, it is possible to further reduce the size of the probe unit corresponding to a higher-density circuit board while sufficiently reducing the manufacturing cost.

  According to the circuit board inspection apparatus of the fifth aspect, by providing the probe unit, it is possible to realize an effect similar to the effect of the probe unit.

1 is a configuration diagram showing a configuration of a circuit board inspection device 1. FIG. 2 is a configuration diagram showing a configuration of a probe unit 2. FIG. 3 is a cross-sectional view of the probe unit 2. FIG. FIG. 3 is a plan view of the probe unit 2 as viewed from the distal end 12a side of the probe 12. FIG. 5 is a first explanatory view illustrating a method for manufacturing the probe unit 2. FIG. 5 is a second explanatory view explaining the method for manufacturing the probe unit 2. FIG. 6 is a third explanatory view explaining the method for manufacturing the probe unit 2. 4 is a cross-sectional view showing a configuration of a probe unit 202. 4 is a cross-sectional view showing a configuration of a probe unit 302. FIG. 4 is a cross-sectional view showing a configuration of a probe unit 402. 4 is a cross-sectional view showing a configuration of a probe unit 502. FIG. 4 is a cross-sectional view showing a configuration of a probe unit 602. FIG.

  Embodiments of a probe unit, a circuit board inspection apparatus, and a probe unit manufacturing method according to the present invention will be described below with reference to the drawings.

  First, the configuration of the circuit board inspection apparatus 1 will be described. A circuit board inspection apparatus 1 shown in FIG. 1 is configured to be able to perform an electrical inspection on a circuit board 100 as an example of a probing object. Specifically, as shown in the figure, the circuit board inspection apparatus 1 includes a probe unit 2, a moving mechanism 3, a circuit board support section 4, an inspection section 5 and a control section 6.

  The probe unit 2 is an example of a probe unit, and includes a holding unit 11 and a plurality of probes 12 as shown in FIG.

  As shown in FIG. 2, the holding unit 11 is configured by a single plate-like body and holds the probe 12. In this case, the holding part 11 is comprised with resin which has nonelectroconductivity (insulating property) as an example. As shown in FIG. 3, the holding portion 11 is formed with an insertion hole 11 c into which the covered conducting wire 21 constituting the probe 12 can be inserted.

  As shown in FIGS. 3 and 4, the probe 12 is composed of a covered conductive wire 21 (an example of a linear or rod-shaped conductor). The covered conducting wire 21 is configured by forming an insulating film 21b around the conductor portion 21a (a portion excluding the end surface 21d). In the probe 12, as an example, a magnet wire having an outer diameter D <b> 2 of about 50 μm to 500 μm is used as the coated conductor 21. Further, as shown in FIG. 3, the probe 12 has a front end portion 12a (that is, a front end portion 21c of the covered conducting wire 21) that is one surface of the holding portion 11 (the lower surface in FIG. It is inserted into the insertion hole 11c of the holding part 11 so as to protrude from the holding part 11, and is held by the holding part 11 via an elastic adhesive 13 as an elastic material filled in the insertion hole 11c. In this case, the protruding length of the front end portion 12a from the lower surface 11a can be arbitrarily defined according to the outer diameter D2 or the material of the coated conducting wire 21. In the probe unit 2, the protruding length is defined as about 10 to 100 times the outer diameter D2 as an example. 2 and 3 and FIGS. 6 to 12 to be described later, the ratio of the protruding length of the tip 12a and the length of the other part is shown in a ratio different from the actual ratio.

  As the elastic adhesive 13, various adhesives that have fluidity in an initial state and have a property of solidifying in an elastic state after application (supply) can be used. Specifically, in the probe unit 2, as an example, a natural rubber adhesive, a synthetic rubber adhesive, a silicone adhesive, a modified silicone adhesive, or the like is used as the elastic adhesive 13.

  In this probe unit 2, as shown in FIG. 3, the probe 12 is held by the holding portion 11 via the elastic adhesive 13, and therefore, the tip end portion 12 a is used when probing the terminal 101 of the circuit board 100 as the probing object. When a force is applied to the (leading end portion 21c of the covered conducting wire 21), the elastic adhesive 13 is elastically deformed, so that the probe 12 extends in the direction along the central axis A of the insertion hole 11c (the vertical direction in the figure). Can be moved. Further, at the time of probing, the distal end portion 12a presses the terminal 101 by the elastic force accompanying the elastic deformation of the elastic adhesive 13, so that the distal end portion 12a reliably contacts and is electrically connected to the terminal 101. Moreover, since the probe 12 is comprised by the covered conducting wire 21 insulated by the insulating film 21b, and the covered conducting wire 21 is hold | maintained by the holding | maintenance part 11 which has nonelectroconductivity, other probes 12 (other covered conducting wires 21) are comprised. ) Is insulated.

  The moving mechanism 3 is configured to be able to fix the probe unit 2, and moves the probe unit 2 in a direction toward and away from the circuit board support unit 4 according to the control of the control unit 6. The circuit board support 4 is configured to hold the circuit board 100. The inspection unit 5 performs predetermined electrical inspections such as a disconnection inspection and a short circuit inspection on the circuit board 100 based on electric signals input / output via the probes 12 of the probe unit 2 according to the control of the control unit 6. Execute. The control unit 6 moves the probe unit 2 fixed to the moving mechanism 3 by controlling the moving mechanism 3. In addition, the control unit 6 controls the inspection unit 5 to perform an electrical inspection on the circuit board 100.

  Next, a method for manufacturing the probe unit 2 will be described with reference to the drawings.

  First, as shown in FIG. 5, the same arrangement pattern as the arrangement pattern (see FIG. 2) of the terminals 101 of the circuit board 100 serving as the probing target for the plate-like body made of non-conductive resin. The holding part 11 is produced by forming the insertion hole 11c. In this case, when the outer diameter D2 of the coated conducting wire 21 constituting the probe 12 is 50 μm, for example, the inner diameter D1 of the insertion hole 11c is defined to be about 100 μm (that is, about twice the outer diameter D2) (see FIG. 3).

  Next, as shown in FIG. 6, the above-described covered conducting wire 21 having an outer diameter D2 of 50 μm is inserted into each insertion hole 11c of the holding portion 11. At this time, as shown in FIG. 7 and FIG. 7, the covered conductor 21 is inserted into the insertion hole 11 c so that the tip 21 c of the covered conductor 21 protrudes from the lower surface 11 a of the holding portion 11.

  Subsequently, when the insertion of the covered conductor 21 into all the insertion holes 11c is completed, as shown in FIG. 7, the other surface of the holding portion 11 (the upper surface in FIG. The elastic adhesive 13 (silicone adhesive as an example) is applied (supplied) to the edge of the insertion hole 11c (that is, around the covered conductive wire 21 inserted through the insertion hole 11c). Next, suction is performed from the lower surface 11 a side of the holding portion 11. At this time, as shown in FIG. 3, the elastic adhesive 13 applied to the upper surface 11 b is drawn into the gap between the inner peripheral surface of the insertion hole 11 c and the covered conductor 21 and is filled in the gap.

  Subsequently, after the elastic adhesive 13 is solidified (dried), the tip portion 21 c of each coated conductor 21 is cut or polished to project the tip portion 21 c from the lower surface 11 a of the holding portion 11. Align so that the length is a predetermined length. In this case, when an oxide film is formed on the end surface 21d of the tip portion 12a, or when fragments or dirt of the insulating film 21b adhere to the end surface 21d, they are removed by cutting or polishing.

  Next, a plating process (for example, a gold plating process) is performed on the end surface 21d of the tip end portion 21c of the coated conductive wire 21 to form a conductive (low resistance) metal film on the end surface 21d. Thus, the probe unit 2 is completed.

  In this case, the probe unit 2 is composed of a holding portion 11 composed of a single plate-like body and a probe 12 composed of a covered conducting wire 21. For this reason, this probe unit 2 has a simple structure with fewer types of components compared to a conventional probe unit of a type in which a pin-shaped probe is supported by a plurality of members so as to be buckled. Further, since the structure is simple, as described above, the manufacturing process is also simple, and the manufacturing cost can be reduced accordingly.

  Next, a method for performing an electrical inspection on the circuit board 100 using the circuit board inspection apparatus 1 will be described with reference to the drawings.

  First, the probe unit 2 is fixed to the moving mechanism 3. Next, the circuit board 100 is fixed to the circuit board support 4. Subsequently, the circuit board inspection apparatus 1 is operated. At this time, the control unit 6 controls the moving mechanism 3 to move the probe unit 2 in a direction approaching the circuit board 100 (downward in FIG. 2). Next, when the tip 12a of each probe 12 of the probe unit 2 comes into contact with the terminal 101 of the circuit board 100, the control unit 6 controls the moving mechanism 3 to apply a predetermined amount of load to the probe unit 2. The probe unit 2 is further moved downward while being applied downward.

  At this time, the load applied to the probe unit 2 is dispersed to each probe 12, and the dispersed load presses the terminal 101 of the circuit board 100. Here, in this probe unit 2, the probe 12 (the coated conducting wire 21 constituting the probe 12) is held by the holding unit 11 via the elastic adhesive 13. For this reason, in the probe unit 2, when the reaction force of the pressing force against the terminal 101 is applied to each probe 12 during probing, the elastic adhesive 13 holding the probe 12 is elastically deformed and held thereby. Movement of the probe 12 along the central axis A of the insertion hole 11c in the portion 11 is allowed. Therefore, even when the distance between the distal end portion 12a of each probe 12 and the terminal 101 is different for each probe 12, the distal end portion 12a of each probe 12 and the terminal are elastically deformed. 101 can be reliably brought into contact with.

  Subsequently, the inspection unit 5 performs an electrical inspection on the circuit board 100 based on an electrical signal input / output via the probe 12 under the control of the control unit 6. Next, when the inspection of the circuit board 100 is completed, the control unit 6 controls the moving mechanism 3 to move the probe unit 2 in a direction away from the circuit board 100. Subsequently, when an electrical inspection is performed on another circuit board 100, the above steps are repeated.

  As described above, in the probe unit 2, the circuit board inspection apparatus 1, and the probe unit manufacturing method, the holding portion 11 is formed by forming the insertion hole 11 c in the plate-like body, and the distal end portion of the covered conductive wire 21 that functions as the probe 12. The covered conducting wire 21 is inserted into the insertion hole 11c so that 21c protrudes from the lower surface 11a of the holding portion 11, and the covered conducting wire 21 is held via the elastic adhesive 13 so as to be movable along the central axis A of the insertion hole 11c. The probe unit is manufactured by filling the insertion hole 11 c with the elastic adhesive 13 so as to be held by the probe 11. That is, the probe unit 2 includes a holding portion 11 configured by a single plate-like body and a probe 12 configured by a covered conductive wire 21. For this reason, according to this probe unit 2, the circuit board inspection apparatus 1, and the probe unit manufacturing method, the probe unit is compared with a conventional probe unit of a type in which a pin-shaped probe is buckled by a plurality of members. Since the number of types of component 2 is simple and the structure is simple, the manufacturing process can be simplified. As a result, the manufacturing cost can be reduced sufficiently. Therefore, according to the probe unit 2, the circuit board inspection apparatus 1, and the probe unit manufacturing method, the probe unit 2 can be easily miniaturized corresponding to the high-density circuit board 100 because the structure is simple. The manufacturing cost can be sufficiently reduced. In addition, according to the probe unit 2, the circuit board inspection apparatus 1, and the probe unit manufacturing method, the contact and separation between the electrode for inputting and outputting signals and the connecting portion of the probe are repeated every time probing is performed. On the other hand, since there is no portion that repeats contact and separation every time such probing is performed, it is possible to reliably prevent the occurrence of a failure due to contact failure in that portion.

  Further, according to the probe unit 2 and the circuit board inspection apparatus 1, since the probe 12 is composed of the coated conductor 21, the coated conductor 21 itself has insulation, so that the respective coated conductors 21 can be reliably connected to each other. Each insulated conductor 21 can be held by the holding portion 11 in an insulated state. In addition, by configuring the probe 12 with the coated conducting wire 21, the coated conducting wire 21 can be directly connected to the inspection unit 5. That is, the coated conductor 21 as the probe 12 can be used as a lead wire for connection with the inspection unit 5 as it is. For this reason, compared with the structure using the connection lead wire separate from the conductor as the probe 12, the probe unit 2 is not necessary for the connection between the conductor as the probe 12 and the connection lead wire. The manufacturing cost can be further reduced.

  Next, the probe unit 202 shown in FIG. 8 will be described. In the following description, the same components as those of the probe unit 2 described above are denoted by the same reference numerals, and redundant description is omitted. The probe unit 202 is another example of the probe unit, and includes a holding unit 11 and a probe 12 as shown in FIG. In this case, two covered conductors 21 that respectively constitute two (a plurality of examples) probes 12 are inserted into the insertion holes 11 c of the holding unit 11. Further, each covered conductor 21 inserted through the insertion hole 11c is movable along the central axis A of the insertion hole 11c and is insulated from each other via an elastic adhesive 13 filled in the insertion hole 11c. Are held by the holding unit 11. In addition, the number of the probes 12 inserted through one insertion hole 11c is not limited to two, and can be defined as an arbitrary plurality.

  According to this probe unit 202, since a plurality of probes 12 are inserted into one insertion hole 11c, each probe 12 is compared with a configuration in which one probe 12 is inserted into one insertion hole 11c. Can be narrowed. For this reason, according to this probe unit 202, the probe unit 202 can be further reduced in size corresponding to the higher-density circuit board 100 while sufficiently reducing the manufacturing cost.

  Next, the probe unit 302 shown in FIG. 9 will be described. In the following description, the same components as those of the probe unit 2 described above are denoted by the same reference numerals, and redundant description is omitted. The probe unit 302 is still another example of the probe unit, and includes a holding unit 11 and a probe 12 as shown in FIG. In this case, two covered conducting wires 21 respectively constituting two (a plurality of examples) probes 12 are inserted into the insertion holes 11c of the holding portion 11, and each covered conducting wire 21 is connected to the central axis A of the inserting hole 11c. The holding portion 11 is held via an elastic adhesive 13 which is movable along the other and is insulated from each other and filled in the insertion hole 11c. Moreover, as shown in the figure, each probe 12 (each covered conducting wire 21 inserted through one insertion hole 11c) is inserted into the insertion hole 11c in a twisted state.

  According to this probe unit 302, since a plurality of twisted probes 12 are inserted into one insertion hole 11c, the interval (pitch) between the plurality of probes 12 inserted into one insertion hole 11c is set. It can be narrowed further. For this reason, according to the probe unit 302, the probe unit 302 can be further reduced in size corresponding to the higher-density circuit board 100 while sufficiently reducing the manufacturing cost.

  The probe unit and the circuit board inspection apparatus are not limited to the above configuration. For example, although the example using the coated conductor 21 as a conductor formed in a linear shape has been described above, a configuration using a conductor formed in a rod shape instead of the coated conductor 21 may be employed.

  Further, the configuration example (see FIG. 3) in which the portion of the coated conductor 21 constituting the probe 12 excluding the end surface 21d is covered with the insulating film 21b has been described above, but as shown in FIG. 10, the peripheral surface of the tip portion 21c. The probe unit 402 can be configured by using the probe 12 composed of the coated conductive wire 21 from which the insulating film 21b is removed in a part (excluding the end surface 21d), and the circuit board includes the probe unit 402. An inspection device can also be configured.

  Further, as shown in FIG. 11, the probe unit 502 is configured by using the probe 12 composed of the covered conducting wire 21 in which the distal end portion 21c is formed in a needle shape (a shape gradually narrowing toward the distal end). The circuit board inspection apparatus can be configured with the probe unit 502. In addition, as shown in FIG. 12, the probe unit 602 can be configured by using the probe 12 configured by the covered conducting wire 21 in which the tip end portion 21c is formed in a hemispherical shape, and the probe unit 602 is provided. A circuit board inspection apparatus can also be configured.

DESCRIPTION OF SYMBOLS 1 Circuit board inspection apparatus 2,202,302 Probe unit 5 Test | inspection part 11 Holding | maintenance part 11a Lower surface 11c Insertion hole 12 Probe 12a Tip part 13 Elastic adhesive 21 Covering conductor 21a Conductor part 21b Insulating film 21c Tip part 100 Circuit board 101 Terminal A Central axis

Claims (6)

A probe unit comprising a plurality of probes and a holding unit for holding each probe,
The holding part is composed of a plate-like body having an insertion hole,
The probe is composed of a linear or rod-like conductor inserted through the insertion hole so that a tip portion protrudes from one surface of the holding portion, and is movable along the center axis of the insertion hole; A probe unit held by the holding portion via an elastic material filled in the insertion hole in a state of being insulated from other conductors.   The probe unit according to claim 1, wherein the probe is formed of a coated conductor.   The probe unit according to claim 1 or 2, wherein a plurality of the probes are inserted into one insertion hole.   The probe unit according to claim 3, wherein the plurality of probes are inserted through the one insertion hole in a twisted state.   An electrical inspection for the circuit board based on the probe unit according to any one of claims 1 to 4 and an electrical signal input / output through the probe of the probe unit brought into contact with the circuit board as a probing object. A circuit board inspection apparatus comprising: an inspection unit that executes A probe unit manufacturing method for manufacturing a probe unit including a plurality of probes and a holding unit that holds the probes.
Forming the holding part by forming an insertion hole in the plate-like body,
The conductor is inserted into the insertion hole so that the tip of a linear or rod-shaped conductor that functions as the probe protrudes from one surface of the holding part,
The elastic material is inserted into the insertion hole so that the electric conductor is held by the holding portion via the elastic material while being movable along the central axis of the insertion hole and insulated from the other electric conductor. A probe unit manufacturing method for filling and manufacturing the probe unit.

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