JPH07260825A - Probe for measuring signal - Google Patents

Abstract

PURPOSE:To obtain a signal-measuring probe in a structure whereby a flow- measuring resistance can be incorporated, and the probe and a reference potential contact are united with a narrow pitch to be movable freely on an electronic circuit package. CONSTITUTION:A shunt resistance 7 of a signal-measuring system, a rigid coaxial part 6 connected to the shunt resistance 7 inside a movable element 8, and a probe contact 5 to be in touch with a reference potential pad 10 thereby to supply a reference potential of the measuring system are united at the movable element 8, thereby constituting a unit of measuring part. The movable element 8 of the measuring part is fixed by a cover 19 to a main body 9 of a measuring probe. The probe main body 9 is temporarily fixed to a holding instrument 23 by a screw shaft 22 to be movable up and down. The holding instrument 23 is temporarily secured in a slidable fashion to a slide rail 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal measuring probe used when measuring a signal waveform of an electronic circuit package, and particularly used when measuring a high-speed signal waveform of an electronic circuit package mounted with high density. Signal measuring probe.

[0002]

2. Description of the Related Art Conventionally, in a signal measuring device for measuring a signal waveform of an electronic circuit package, a supporting plate for supporting a coaxial movable contact probe is mounted on an electronic circuit package as a circuit board to be measured. A structure in which a guide post fixed vertically to the plate is movably inserted (Japanese Patent Laid-Open No. 60-
According to Japanese Patent Laid-Open No. 158357 (see FIG. 1 in particular), the signal waveform is measured by bringing the tip of the coaxial movable probe into contact with the measurement pad of the electronic circuit package.

Alternatively, as shown in FIG. 7, a reference potential connection terminal 101 for guiding the tip of the coaxial type measurement probe 102 to a predetermined measurement pad 104 is electronically connected to the predetermined measurement pad 104. Circuit package 105
Mounted on top, the reference potential connection terminal 101,
The measurement probe 102 is configured to be connected to the reference potential on the electronic circuit package 105 near the measurement pad 104.
The signal waveform is measured by bringing the tip, which is the central conductor of the measurement probe 102, into contact with the measurement pad 104 in a state where the outer conductor is connected to the reference potential.

[0004]

However, in the above-mentioned conventional signal measuring device using the coaxial movable contact probe, the probe is connected to the signal measuring pad by vertically moving the support plate positioned by the guide post. Therefore, it is necessary to support the probe on the support plate in accordance with the position of the measurement pad of the electronic circuit package. For this reason, the measuring device becomes expensive, and since a shunt resistance for shunting the signal current cannot be attached, branching (shunt) measurement is difficult.

On the other hand, in the signal measuring device using the reference potential connecting terminal shown in FIG. 7, the outer conductor of the coaxial measuring probe is connected to the reference potential by the reference potential connecting terminal mounted in the electronic circuit package. Since it is configured so that it can be connected with the
There is a problem that the accommodability of the signal wiring pattern in the vicinity of the soldering portion of the reference potential connection terminal is deteriorated, and as a result, it is difficult to provide the measurement pads in close contact with high density.

The present invention has been made in view of the above-mentioned problems of the prior art, and has a structure in which a shunt current measuring resistor can be built-in, and a measuring probe and a reference potential contact are integrated at a narrow pitch. An object of the present invention is to provide a signal measuring probe that can freely move on a circuit package.

[0007]

The present invention for achieving the above object provides a signal measuring probe for use in measuring a signal waveform of a circuit board to be measured by a signal measuring device. Installed on the measured surface side of the circuit board,
A measurement probe body that is movable opposite to the circuit board to be measured, a conductive movable piece attached to the measurement probe body while being urged toward the circuit board to be measured, and a center conductor. A rigid coaxial portion formed coaxially with an insulating material interposed between the outer conductor and a shunt resistance for shunting a signal current, which is connected to a signal measurement pad of the circuit board under test, And a probe contact connected to a reference potential pad of the circuit board to be measured, and the shunt resistor and the contact probe are adjacent to each other from one end side of the movable piece facing the circuit board to be measured. The rigid coaxial portion is fitted from the other end side of the movable piece so that the center conductor of the rigid coaxial portion and the shunt resistor are electrically connected to each other, and Tsu DOO coaxial portion of the outer conductor and said contact probe is characterized in that it is electrically connected.

Further, the measurement probe main body is provided with an X-axis so that the shunt resistance and the contact probe can be moved to an arbitrary measurement pad on the circuit board to be measured.
It is preferably attached to the Y stage.

[0009]

In the present invention configured as described above, the measurement probe body is moved to the positions of the signal measurement pad and the reference potential pad on the circuit board to be measured to be measured, and the measurement probe body is placed on the circuit board to be measured. Move toward each other. Then, the shunt resistance and the probe fitted from one end (the end facing the circuit board to be measured) of the conductive movable piece attached to the measurement probe main body while being urged toward the circuit board to be measured. The contact is in contact with the signal measurement pad and the reference potential pad. At this time, a reference potential is connected to the outer conductor of the rigid coaxial portion derived from the other end of the movable piece through a probe contact, and the center conductor of the rigid coaxial portion is connected to the lead conductor of a shunt resistance to measure a signal. The signal from the pad is transmitted. As a result, stable signal waveform measurement that matches the reference potential of the circuit board under measurement becomes possible. In addition, shunt measurement can also be performed.

In particular, when a plurality of signal measurement pads and a plurality of reference potential pads corresponding to the signal measurement pads are closely arranged on the circuit board to be measured and arranged in high density, the contact probe and the shunt resistor are sandwiched. Corresponding to each other at a pitch, the reference potential obtained from the contact probe and the measurement signal from the shunt resistance can be collectively collected in the rigid coaxial portion and developed above the circuit board to be measured.

Furthermore, it is necessary to mount the above-mentioned measurement probe main body on the XY stage and move it so that it is supported by the support plate in accordance with the position of the measurement pad on the circuit board to be measured as in the conventional case. There is no.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing an embodiment of the signal measuring probe of the present invention, and FIG. 2 is an assembled sectional view of a measuring portion constituting an embodiment of the signal measuring probe of the present invention. Is. 3A and 3B are configuration diagrams of an embodiment of the signal measuring probe of the present invention, where FIG. 3A is a front view, FIG. 3B is a side view, and FIG. 3C is a plan view.

As shown in FIG. 1, the signal measuring probe of this embodiment is arranged corresponding to the position of a reference potential pad 10 arranged on the surface of an electronic circuit package (not shown) as a circuit board to be measured. The probe contact 5 whose tip is movable in the axial direction, the shunt resistance 7 arranged corresponding to the position of the signal measurement pad 11 arranged on the surface of the electronic circuit package (not shown), and the central conductor. It has a measuring portion integrally formed with a conductive movable piece 8 and a rigid coaxial portion 6 formed coaxially with an insulating material interposed between the outer conductor and the outer conductor.

The structure of the measuring section will be described in detail with reference to FIG. 2. The root of the probe contact 5 is an electrically stable connection such as soldering or caulking to the movable piece 8 and mechanically. Fix it with a method that can hold it firmly. The rigid coaxial portion 6 is sunk into the movable piece 8 coaxially with the shunt resistor 7. A coupling portion 13 is formed on the tip end side of the sinking rigid coaxial portion 6, and this coupling portion 1
3, the movable piece 8 facing the electronic circuit package (not shown) is inserted from one end portion (downward in the drawing) to form the coupling portion 13.
The lead of the shunt resistor 7 introduced into the core of the movable piece 8 and the central conductor 14 of the rigid coaxial portion 6 which is inserted from the other end (upper side in the drawing) of the movable piece 8 and introduced into the coupling portion 13 are firmly connected.
If the coupling portion 13 is used as a contact, the shunt resistor 7 can be easily replaced. As described above, when the lead of the shunt resistor 7 and the central conductor 14 of the rigid coaxial portion 6 are connected to each other by soldering for firm connection or a contact having a small conductor diameter for easy replacement, the movable piece 8
It is possible to form a coaxial structure in which the inner wall of the coupling part is an outer conductor.

On the other hand, since the rigid coaxial section 6 can be constructed by a coaxial structure part matching the characteristic impedance of the measuring instrument, the signal waveform is not reflected even if the tip of the shunt resistor 7 is contacted to shunt the signal current. Can be measured. Also, by soldering or crimping,
Movable piece 8 on the opposite side of the electronic circuit package (not shown)
When the outer conductor 15 of the rigid coaxial portion 6 is attached to the end of the, the outer conductor 15 of the rigid coaxial portion 6 and the probe contact 5 are electrically integrated. Therefore, the shunt resistance 7
Of the contact probe 5 and the reference potential pad 10 (see FIG. 1).
When the measurement is carried out by contacting with, the stable signal waveform measurement which matches the reference potential of the electronic circuit package (not shown) becomes possible.

A through hole 16 is formed in the movable piece 8 in parallel with the probe contact 5 and the shunt resistor 7,
A coil spring 12 is attached to the rigid coaxial portion 6.

The signal measuring probe of this embodiment is constructed by assembling the measuring section having the above-mentioned configuration together with the respective parts as shown in FIG.

That is, by inserting the pin 17 into the through hole 16 of the movable piece 8 while press-fitting the pin 17 into the through hole 18 of the probe body, the movable piece 8 is attached to the measuring probe main body 9 so as to be vertically movable. To be Similarly to this, the movable piece 8
Are attached to the measuring probe main body 9 so as to be adjacent to each other, and then the coil springs 12 mounted on the respective rigid coaxial portions 6 are pressed down by the bottom surface of the cover 19 so that the cover 19 is fixed. The measuring unit having the above-described structure is attached to the measuring probe main body 9 so as to be vertically movable independently.

Then, after the screw shaft 22 is screwed into the female thread portion 21 of the measuring probe main body 9, the convex portion 20 of the measuring probe main body 9 is mounted in the groove portion 24 of the holder 23, from the top of the drawing. By fixing the holding plate 25 to the holder 23 so that the upper end of the screw shaft 22 penetrates, the measurement probe main body 9 is assembled to the holder 23 so as to be vertically movable by the rotation of the slot 26 of the screw shaft. Has been.

In FIG. 3, a coaxial connector 27 which can be connected to a measuring coaxial cable from a measuring instrument is attached to the other end of the rigid coaxial portion 6 submerged in the coupling portion 13. Even if the rigid coaxial portion 6 is lengthened as necessary, it does not affect the measurement accuracy, and the coaxial connector 27 can be deployed by utilizing the front, rear, left and right spaces above the measurement pad. Therefore, it is not necessary to be restricted by the arrangement dimension of the signal measurement pad.

FIG. 4 is a perspective view showing the configuration of an embodiment of the signal measuring probe of the present invention. FIG. 5 shows a simple X-type equipped with an embodiment of the signal measuring probe of the present invention.
The structure of a Y stage is shown, (a) is a top view, (b) is a side view. 6A and 6B show the configuration of a precision moving XY stage on which an embodiment of the signal measuring probe of the present invention is mounted. FIG. 6A is a plan view and FIG. 6B is a side view.

The signal measuring probe having the above-described structure is assembled as shown in FIG. 4, and the holding piece 28 (see FIG. 1) is inserted into the slide groove 30 of the slide rail 29 to hold the holder 2.
If it is strongly screwed into the holding piece 28 via 3, it cannot be moved, but if it is lightly screwed in, the signal measuring probe can be moved along the slide groove 30. Further, as shown in FIG. 5, a mounting table on which an electronic circuit package (not shown) is mounted is provided, and the signal measuring probe shown in FIGS. 1 and 4 is slidably held on the mounting table. If the signal measuring probe is attached to a simple XY stage that is configured to hold the slide rail 29 that is slidably held in the direction orthogonal to the sliding direction of the signal measuring probe, the signal measuring probe will be electronic. It can be moved to any position on the circuit package. When the measurement is performed using the XY stage shown in FIG. 5, after loosening the bridge screw 32 of the gate-shaped beam 31 of the XY stage shown in FIG. 5, the measurement is performed on the electronic circuit package (not shown). Aim at the signal measurement pad 11 (see Fig. 1),
By moving the measurement probe main body 9 along the sled rail 29, the measurement probe main body 9 can be arranged immediately above the signal measurement pad 11 (see FIG. 1). Therefore, when the measuring probe main body 9 is lowered by operating the slotted portion 26 of the screw shaft 22, the probe contact 5 hits the reference potential pad 10, and when the measuring probe main body 9 is further lowered, the tip of the shunt resistance 7 is reached. Hits the signal measuring pad 11. As a result, stable signal waveform measurement that matches the reference potential of the electronic circuit package (not shown) becomes possible.

Further, by selecting the spring constants of the coil spring in the probe contact and the coil spring 12 above the movable piece 8, the probe contact and the tip of the shunt resistor 7 can be brought into contact with the measurement pad with an appropriate contact force. it can.

Further, the present invention is not limited to this, but if the shape behind the signal measuring probe is changed so that the slide rail 29 shown in FIG. 6 is mounted on a precision movable XY stage whose position can be finely adjusted. Also with such a configuration, the signal measuring probe can be moved corresponding to the position of the measurement pad.

[0026]

Since the present invention is constructed as described above, it has the following effects.

According to the first aspect of the present invention, the contact probe and the shunt resistance are adjacent to each other with a pitch, and the reference potential obtained from the contact probe and the measurement signal from the shunt resistance are collected together in the rigid coaxial portion to be measured circuit. Since it can be deployed above the board, the signal waveform can be expanded even when the signal measurement pad and multiple reference potential pads corresponding to the signal measurement pad are closely arranged on the circuit board under test and are arranged in high density. Can be measured. In addition, since a shunt resistor can be attached corresponding to the signal measurement pad, it is possible to perform measurement with a part of the signal current shunted.

According to the second aspect of the invention, since the measuring probe main body is attached to the XY stage and is movable,
In addition to the effect of the invention described in claim 1, it is possible to perform measurement even when the size of the electronic circuit package and the position of the measurement pad are different, and it is possible to prevent the measurement device from becoming expensive.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a signal measuring probe of the present invention.

FIG. 2 is an assembled sectional view of a measuring member that constitutes an embodiment of the signal measuring probe of the present invention.

3A and 3B are configuration diagrams of an embodiment of a signal measuring probe of the present invention, in which FIG. 3A is a front view, FIG. 3B is a side view, and FIG.

FIG. 4 is a perspective view showing the configuration of an embodiment of the signal measuring probe of the present invention.

5A and 5B show a configuration of a simple XY stage on which an embodiment of a signal measuring probe of the present invention is mounted, wherein FIG. 5A is a plan view and FIG. 5B is a side view.

FIG. 6 shows a configuration of a precision movable XY stage on which an embodiment of a signal measuring probe of the present invention is mounted,
(A) is a plan view and (b) is a side view.

FIG. 7 is a side view showing a conventional signal measuring device adopting a grounding terminal type.

[Explanation of symbols]

 5 probe contact 6 rigid coaxial portion 7 shunt resistance 8 movable piece 9 measurement probe body 10 reference potential pad 11 signal measurement pad 12 coil spring 13 coupling portion 14 center conductor 15 outer conductor 16 through hole 17 pin 18 probe body through hole 19 cover 20 Convex Part 21 Female Thread Part 22 Screw Shaft 23 Holding Tool 24 Groove Part 25 Holding Plate 26 Grating Part 27 Coaxial Connector 28 Holding Piece 29 Slide Rail 30 Slide Groove 31 Gate Beam 32 Bridge Part Screw

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Tetsuro Mikazuki 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Kazuhiko Sakakibara 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Hironori Oka 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. A signal measuring probe used when measuring a signal waveform of a circuit board under measurement by a signal measuring device, wherein the measured object is installed on the side of the surface under measurement of the circuit board under measurement. A measurement probe body that is movable opposite to the circuit board; a conductive movable piece that is attached to the measurement probe body while being urged toward the circuit board to be measured; a center conductor and an outer conductor. A rigid coaxial part formed coaxially with an insulating material interposed between the rigid coaxial part, a shunt resistance for shunting a signal current, which is connected to a signal measurement pad of the circuit board under test, and the circuit under test A probe contact connected to a reference potential pad of the substrate, and the shunt resistance and the contact probe from one end side of the movable piece facing the circuit board to be measured. And are fitted adjacent to each other, the rigid coaxial portion is fitted from the other end side of the movable piece, the central conductor of the rigid coaxial portion and the shunt resistance are electrically connected, and the rigid coaxial portion of A signal measuring probe, wherein an outer conductor and the contact probe are electrically connected. 2. The measurement probe main body is attached to an XY stage such that the shunt resistance and the contact probe can be moved to an arbitrary measurement pad on the circuit board to be measured. The signal measuring probe according to claim 1.