JPH0772209A - Probe for detecting component on circuit board - Google Patents

Abstract

PURPOSE:To provide a probe which can surely detect even though the height of parts is very low and can find even open-circuit parts. CONSTITUTION:A contact probe 21, a first holding member of electric conduction 26 for interposing an insulation part 27 in the lower side thereof and movably holding under a conductive state with resistance, a second holding member of insulation 31 for fixing thereon and movably holding the upper side of the contact probe 21, an energizing means 32 for pushing out the contact probe 21 up to a part side and contact parts 25, 29 for forming at respective positions where its contact state is separated in response to stroke displacement of the contact probe 21 produced at the time when the contact probe 21 comes into contact with the first holding member 26 in regard to the position where the energized contact probe 21 and the first holding member 26 are into contact with each other are equipped. A detection signal at the time of part presence detection operation of a circuit board to be inspected makes a signal without a part at the time when contact point parts are into contact with each other and produces another signal with a part at the time when they are not into contact with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component presence / absence detection probe for a circuit board inspection machine, and more specifically, it is capable of detecting the presence / absence of even a component of extremely small height and detecting the presence / absence of disconnection. The present invention relates to a component presence / absence detection probe for a circuit board inspection machine capable of detecting.

[0002]

2. Description of the Related Art A disconnection or short circuit of printed wiring on a circuit board,
2. Description of the Related Art In order to perform various inspections such as the type and performance of components mounted on a circuit board, there is an inspection machine that inspects a probe by contacting it with a measurement site. In such an inspection machine, in addition to using a dedicated jig (pin board) in which the probe pins are fixed according to the circuit board, the probe pins are moved to a predetermined part by the XY unit and the Z axis unit. Some have made the necessary measurements.

In the above-mentioned circuit board inspection machine in which the probe pins can be freely moved in three dimensions, when detecting the presence or absence of a component, a component presence / absence detection probe as shown in FIG. 4 is attached to the Z-axis unit. Is going. The component presence / absence detection probe 1 is configured by providing a holding cylinder 2 with first and second contact probes 3 and 5 movably in the axial direction.

Of these, the first contact probe 3
Is attached to the front end side of the holding cylinder 2 via a conductive collar 4, and its front end portion 3a comes into contact with a component. In addition, the second contact probe 5 has an insulating collar 6 on the rear end side of the holding tube 2 so that the front end 5a is located apart from the rear end 3b of the first contact probe 3 by a gap A. Is attached through. These first and second contact probes 3 and 5 have their respective rear end portions 3b and front end portions 5a set in a conductive state, and are further urged by a coil spring (not shown) so as to project toward the component side. Has been done. Then, the rear end portion 3b of the first contact probe 3 and the tip portion 5a of the second contact probe 5 under such an initial state.
The gap between and is set to A.

On the other hand, the holding cylinder 2 is made of a conductive material, and is in a conductive state with the first contact probe 3 held by the holding cylinder 2 via a conductive collar 4.
In addition, the second contact probe 5 has an insulating collar 6
Since it is attached to the holding cylinder 2 via
And the second contact probe 5 are in an insulated state. Then, lead wires 8 and 9 are connected to the surface of the holding cylinder 2 and the rear end portion 5b of the second contact probe 5, respectively, whereby the detection signal of the component presence / absence detection probe 1 is sent to the measuring instrument side. It is like this.

When the presence / absence of a component on a circuit board is detected by using the component presence / absence detection probe 1 as described above, the component presence / absence detection probe 1 is placed on a detected component (height A or more).
Is positioned and then lowered to bring the tip 3a of the first contact probe 3 into contact with the component. In this state, when there is a component, the first contact probe 3 comes into contact with the component, moves in the holding cylinder 2, and comes into contact with the tip portion 5a of the second contact probe 5. As a result, both become conductive and it is possible to detect that there is a component. If there is no component, the first contact probe 3 does not move, so that the insulation state is maintained,
It is possible to detect the absence of parts.

[0007]

Although the component presence / absence detection probe 1 as described above has a simple structure, the height of the component must be not less than the clearance A between the first and second contact probes 3 and 5. Since the rear end portion 3b and the front end portion 5a which are mutual contact portions do not come into contact with each other, there is a problem that it becomes impossible to detect the presence or absence of a component. Further, if there is a component, it is determined from the short-circuit state of the first and second contact probes 3 and 5 that there is a component. If there is no component, it is determined that the insulation state is maintained and there is no component. There is also a problem that when the wire 1 is disconnected, the presence of the component is erroneously detected as the absence of the component.

The present invention is intended to solve the above-mentioned problems, and even a component having a very small height can be detected regardless of the height of the component, and the component presence / absence detection probe is disconnected. In this case, it is an object of the present invention to provide a component presence / absence detection probe capable of detecting this disconnection state.

[0009]

In order to achieve the above object, the present invention is a circuit for bringing a contact probe into contact with a component of a circuit board to be inspected and outputting a detection signal of the presence or absence of the component by stroke displacement at that time. In a component presence / absence detection probe of a board inspection machine, a contact probe that comes into contact with the component and a lower portion of the contact probe that is movable in the axial direction with an insulating material interposed therebetween and have a predetermined resistance value between them. A conductive first holding member that is originally held in a conductive state, and an insulating second holding member that is fixed to the first holding member to freely hold the upper side of the contact probe in the axial direction. A member, an urging means for pushing the contact probe toward the component side, a part where the contact probe and the first holding member come into contact with each other by the urging means, and The contact probe is provided at each of the parts where the contact state is cut off by the stroke displacement of the contact probe caused when touched, and the contact signal is transmitted between the contact parts when detecting the presence or absence of the component of the circuit board to be inspected. A signal indicating that there is no component is set in the contact state, and a signal indicating that there is a component is set when the contact portions are in the non-contact state.

[0010]

Therefore, when the component presence / absence detection probe is lowered and brought into contact with the component of the circuit board to be inspected, the contact portions that have been in contact with each other until now and are in a short-circuit state are separated from each other, so that the resistance value is kept under a predetermined resistance value. The presence of components can be detected by the resistance value obtained via the contact probe and the first holding member which are in a conductive state with each other. If there is no component at the inspected position, the contact probe will not move even if the component presence / absence detection probe is lowered, so the contact points still contact each other and maintain a short-circuited state. Can be detected.

Further, when the component presence / absence detecting probe is disconnected, the resistance is always infinite regardless of the presence / absence of the component, so that erroneous determination is prevented.

Further, when the contact probe comes into contact with the component, the contact portions are always separated from each other even with a slight stroke displacement, so that this can be reliably detected even if the height of the component is extremely small.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 3 showing a circuit board inspection machine to which the present invention is applied, a component presence / absence detection probe 10 is provided with a mounting height adjusting metal fitting 11 for adjusting its mounting height according to the component height. Attached to the Z-axis unit 12.

The Z-axis unit 12 is attached to the movable portion 13. The Z-axis unit 12 moves the probe 10 to Z
By moving the tip of the probe 10 in the axial direction, the circuit board 1
Contact 4. In the illustrated example, the Z-axis unit 12
Is provided outside the movable part 13.
It may be built in.

The movable portion 13 is attached to the arm 16 of the XY unit 15 so as to be movable in the Y direction. X-
The Y unit 15 includes an arm 16 and a guide rail 17. The Y unit 15 is movable by moving the arm 16 along the guide rail 17 by a driving unit (not shown) and moving the movable unit 13 along the arm 16. The portion 13 is movable in the XY directions.

The circuit board 14 to be inspected is mounted on a pair of support plates 18a and 18b provided in parallel with the guide rails 17. The support plates 18a and 18b are attached to the base 19 so that they are sufficiently separated from each other so as to support near both ends of the circuit board 14.

As shown in FIG. 1, the component presence / absence detection probe 10 according to the present invention includes a metal contact probe 21.
And a first holding member 26 and a second holding member 31 that hold the contact probe 21 movably in the axial direction.

Of these, the lower side of the contact probe 21 defined by the collar portion 24 integrally formed or separately formed of a conductive material and fixed to the first holding member 2.
6 is movably attached. The first holding member 26 is made of a conductive material, and an insulating portion 27 formed by applying an insulating paint or via an insulating collar is interposed on the inner peripheral side thereof. Because
The contact probe 21 and the first holding member 26 are in a non-conductive state with each other.

Moreover, the contact probe 21 and the first holding member 26 in such a non-conductive state have a resistance member 30 such as a resistance wire having a predetermined resistance value (RΩ).
Since it is directly connected and intervened, the specified resistance value (RΩ)
The conductive state is maintained under the condition that the disconnection of the component presence / absence detection probe 10 can be detected.

The contact state is lost due to the stroke displacement of the contact probe 21 that occurs when the contact probe 21 and the first holding member 26 are in contact with each other by the urging means 32 described later and when the contact probe 21 contacts the part 14a. Contact portions 25 and 29 are formed on each of the portions to be formed, that is, on the flange portion 24 of the contact probe 21 and the upper end surface 28 of the first holding member 26, respectively.

On the other hand, the second holding member 31 made of an insulating material for holding the upper side of the contact probe 21 partitioned by the collar 24 is fixedly connected to the first holding member 26, and therefore the contact is fixed. The insulating state is maintained between the probe 21 and the second holding member 31.

Further, the collar portion 24 of the contact probe 21
A biasing means 32 such as a coil spring is attached between the second holding member 31 and the second holding member 31.
As a result, the contact probe 21 is urged in such a direction that the tip portion 22 thereof is always pressed against the component 14a side.

Further, the lead wire 35 is connected to the first holding member 26.
The lead wire 36 is attached to the rear end portion 2 of the contact probe 21.
3 and the detection signal of the component presence / absence detection probe 10 is sent to the measuring instrument via the lead wires 35 and 36.

Next, the operation of this embodiment will be described. As shown in FIG. 3, when detecting whether or not the component 14a is present at a predetermined position on the circuit board 14, the component presence / absence detection probe 10 is attached to the Z-axis unit 12 via the attachment height adjustment fitting 11. In this state, the XY unit 15 is operated to position the movable portion 13 above the component 14a of the circuit board 14 to be inspected. And the Z-axis unit 1
2, the probe 10 is lowered, and the part 14 at the measurement site is
The tip 22 of the contact probe 21 is brought into contact with a.

When the tip portion 22 of the contact probe 21 comes into contact with the component 14a, the contact probe 21 causes the first holding member 26 and the second holding member 31 as shown in FIG.
Move in. As a result, the contact probe 21 is pushed up by a stroke corresponding to the height of the component 14a, and thus the contact portion 29 formed on the upper end surface 28 of the first holding member 26 and the contact probe 21 provided with a function as a stopper. The contact state with the contact point portion 25 formed by the flange portion 24 is released and separated. Therefore, the resistance value (RΩ) obtained from the resistance member 30 is shown between the lead wires 35 and 36. This allows
It is possible to determine that there are parts on the measuring instrument side.

Even if the Z-axis unit 12 is operated and the probe 10 is lowered, if there is no component 14a,
Since the contact probe 21 does not contact the component 14a, the contact probe 21 does not move as shown in FIG. Therefore, the contact portion 25,
29 Lead wires 35 and 36 are not separated from each other.
A short circuit state (≈0Ω) is present between the two, and it can be determined that there are no parts on the measuring instrument side.

The contact probe 2 is attached to the component 14a.
In the initial state (the state shown in FIG. 1) before the contact of 1 with each other, by checking the short circuit state between the lead wires 35 and 36, if the short circuit state is detected, the component presence / absence detection probe 10 is normal and the resistance is infinite. In the case of, the component presence / absence detection probe 10 is found to be defective due to disconnection or the like.

[0028]

As described above, according to the present invention, when the component presence / absence detecting probe is lowered and brought into contact with the component of the circuit board to be inspected, the contact portions which have been in contact with each other and are in the short-circuited state are separated from each other. Therefore, it is possible to detect the state in which there is a component based on the resistance value obtained via the contact probe and the first holding member that are in a conductive state with each other under a predetermined resistance value. If there are no parts at the inspected position,
Even if the component presence / absence detection probe is lowered, the contact probe does not move, so that the contact portions are still in contact with each other and the short-circuit state is maintained, whereby the state of no component can be detected.

Further, in the initial state before the contact probe comes into contact with the component, by checking the contact points with each other, the component presence / absence detection probe is normal if there is a short-circuit state, and the component presence / absence is present if the resistance is infinite. Since it is found that the detection probe is defective due to disconnection or the like, erroneous determination is prevented regardless of the presence or absence of parts.

Moreover, when the contact probe comes into contact with the component, the contact portions are always separated from each other even with a slight stroke displacement, so that this can be reliably detected even if the component height is extremely small.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a state without parts according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state with parts in the embodiment shown in FIG.

FIG. 3 is a perspective view illustrating a main part of a circuit board inspection machine to which the present invention is applied.

FIG. 4 is an explanatory diagram showing a conventional component presence / absence detection probe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Component presence / absence detection probe 11 Mounting unit 12 Z-axis unit 13 Moving part 14 Circuit board 14a Component 15 XY unit 21 Contact probe 22 Tip part 23 Rear end part 24 Collar part 25 Contact part 26 1st holding member 27 Insulating part 28 Upper end surface 29 Contact part 30 Resistance member 31 Second holding member 32 Energizing means 35, 36 Lead wire

Claims (1)

[Claims] 1. In a component presence / absence detection probe of a circuit board inspecting device, wherein a contact probe is brought into contact with a component of a circuit board to be inspected and a stroke displacement at that time outputs a detection signal of presence / absence of the component A first conductive member that holds the probe and the lower side of this contact probe in an axial direction freely with an insulating material interposed therebetween and keeps them in a conductive state under a predetermined resistance value.
A holding member, an insulative second holding member that is fixed to the first holding member and holds the upper side of the contact probe so as to freely move in the axial direction, and a biasing force that pushes the contact probe toward the component side. Means and a portion where the contact probe and the first holding member come into contact with each other by the biasing means, and the contact state is cut off due to stroke displacement of the contact probe that occurs when the contact probe contacts the component. A contact signal is provided, and a detection signal at the time of a component presence / absence detection operation of the circuit board to be inspected is a signal indicating that there is no component when the contact components are in contact with each other, and there is a component when there is no contact between the contact components. A component presence / absence detection probe characterized by being a signal.