JPH01178872A - Structure of grounding conductor for signal measuring device - Google Patents

Abstract

PURPOSE:To conduct signal measurement with little error in measurement, by making a sheet-shaped conductor means windable and by increasing the width thereof gradually from a narrowed end on the leading side thereof. CONSTITUTION:The leading length of a sheet-shaped conductor means 30 can be minimized in relation to a signal detecting position of a measuring probe 22 of a signal measurer 10, since the sheet-shaped conductor means 30 is so wound that it can be pulled out. Therefore, signal detection can be conducted in a state wherein the impedance of the sheet-shaped conductor means 30 is minimized. In addition, the width of the sheet-shaped conductor means 30 increases gradually as it is pulled out from a narrowed end 32 thereof to begin with. Therefore an increase in the impedance with the pulling-out of the sheet- shaped conductor means can be reduced to be small.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a grounding conductor structure used in a signal detector for detecting signals from electronic elements such as various IC packages installed on a printed circuit board. The purpose of the present invention is to provide a grounding conductor structure that suppresses impedance to high-frequency signals without substantially restricting the spatial degree of freedom of a measurement probe when detecting a signal with the measurement probe, and the present invention is a flexible sheet-shaped The sheet-like conductor means has a narrow end serving as a grounding connection end, and the width of the sheet-like conductor means is equal to the narrow end. The sheet-like conductor means is wound around the winding means so that it can be pulled out from the narrow end side, and furthermore, the sheet-like conductor means can be electrically connected to the sheet-like W body means. A grounding conductor structure is constructed with electrical connection means fixed in place.

[Industrial Application Field] The present invention relates to a grounding conductor structure used in a signal detector for detecting signals from various electronic elements such as C installed on a printed circuit board.

As is well known, when performing an electrical characteristic test, a functional test, etc. of an IC on a printed circuit board, a signal passing through each terminal or lead extending from the side of the IC is detected, and the electrical interface of the detected signal is The value and rise characteristics are measured. Specifically, such signal measuring instruments employ measurement probes that are brought into electrical contact with each lead of the IC to pick up the signal passing through the lead;
The signal detected by this measurement probe is input to a measuring instrument such as a tester or an oscilloscope, and thereby the voltage value and rise characteristics of the signal are measured. At this time, the measurement probe is grounded to the chassis on which the printed circuit board is installed, and the voltage value of the detection signal is measured as a potential difference with respect to the chassis.

[Conventional technology]

A measuring probe of a conventional signal measuring instrument incorporates a grounding lead wire, and a lip like a crocodile wire is connected to the distal end of the grounding lead wire. When the measurement probe detects a signal, the measurement probe is grounded to the chassis by clamping the clip at an appropriate location on the chassis.

[Problem to be solved by the invention]

Now, since the grounding lead wire as mentioned above is usually constructed as a conductor consisting of a bundle of thin copper wires, the grounding lead wire is Therefore, if the signal to be detected is a high frequency signal of several tens of megahertz, the impedance of the grounding lead wire will be considerably high, which can cause a large measurement error. The point is considered to be a problem.

Therefore, an object of the present invention is to provide a grounding conductor structure used in a signal detector for detecting a signal from an electronic element such as an IC, which is a grounding conductor structure for use in a measurement probe when detecting a signal with a measurement probe of the signal detector. It is an object of the present invention to provide a grounding conductor structure that suppresses impedance to high frequency signals to a low level without substantially restricting spatial freedom.

[Means to solve the problem]

The grounding conductor structure according to the present invention includes a flexible sheet-like conductor means and a winding means for winding up the sheet-like conductor means so as to be freely drawn out. The sheet-like conductor means has a narrow end serving as a grounding connection end, the width of the sheet-like conductor means gradually increases from the narrow end, and the winding means is provided with a narrow end so that the sheet-like conductor means can be pulled out from the narrow end side. be wound up. The grounding conductor structure further comprises electrical connection means fixed in position for making an electrical connection to the sheet-like conductor means.

[For production]

According to the configuration of the grounding conductor structure as described above, since the sheet-like conductor means is wound up so that it can be freely drawn out, the draw-out length of the sheet-like conductor means with respect to the signal detection position of the measurement probe of the signal measuring device is Therefore, signal detection can be performed with the impedance of the sheet-like conductor means minimized. Further, as the sheet-like conductor means is pulled out from the narrow end, its width gradually increases, so that an increase in impedance accompanying the withdrawal of the sheet-like conductor means can be suppressed to a low level.

〔Example〕

Next, embodiments of the grounding conductor structure according to the present invention will be described with reference to the accompanying drawings.

First, referring to FIGS. 1 and 2, a signal detector for detecting a signal from an electronic element such as an IC is designated by reference numeral 1.
0, signal detector 10 incorporates a grounding conductor structure according to the present invention.

The signal detector 10 includes a hollow casing 12, which can be constructed as a molded article of, for example, plastic, with both ends open. As is clear from FIG. 2, a hollow conductor member 14 is provided immediately inside the hollow casing 12, and both ends of the hollow conductor member 14 are also open as in the case of the hollow casing 12. An elongated opening is formed in the hollow casing 12 along its longitudinal direction, and the hollow conductor member 14 is passed through the opening.
A long protrusion 16 is made to protrude to the outside.

The protrusion 16 can be formed as an integral extension from the peripheral wall of the hollow conductor member 14, and the protrusion 16
An elongated slot 18 extending along the longitudinal direction of the hollow casing 12 is formed at the tip of the hollow conductor member 6 , and the inside of the hollow conductor member 14 is communicated with the outside of the hollow casing 12 through this elongated slot 18 .

A tubular member 20 is disposed inside the hollow conductor member 14 along the central axis thereof, and this tubular member 20 is connected to the hollow conductor member 14.
and the hollow casing 12. Additionally, a measuring probe 22 is disposed within the tubular member 20 along its central axis.
is arranged, and the measuring probe 22 extends through the tubular member 20 .

Further, the measurement probe 22 is supported in an electrically insulated state with respect to the tubular member 20;
a body of insulating material 2 applied therein so as to close the end side of the
4 by penetrating and supporting the measuring probe.

As is clear from FIGS. 1 and 2, on one end side of the hollow casing 12 (i.e. on the left side in FIGS. 1 and 2), one end of the measuring probe 22 is connected to the corresponding end of the tubular member 20. This protruding portion functions as a measurement detecting portion that detects a signal by being brought into contact with a lead of an electronic device such as an IC. On the other hand, a connector member 26 is attached to the other end of the hollow casing 12, from which an electrical cable 28 extends and is connected to a measuring instrument (not shown) such as a tester or oscilloscope. Electrical cable 28 includes a pair of lead wires, one lead connected to measurement probe 22 and the other lead connected to hollow conductor member 14 .

The hollow conductor member 14 is grounded, for example, to a chassis (not shown) of an electronic device by a grounding conductor structure according to the present invention.

In short, the signal voltage detected by the measurement detection section of the measurement probe 22 is measured as a potential difference with respect to the chassis, that is, the hollow conductor member.

Next, a grounding conductor structure constructed according to the present invention for grounding the hollow conductor member 14 will be described in detail.

The grounding conductor structure according to the invention comprises a flexible sheet-like conductor means 30, which has a narrowed end 32 as a grounding connection end and whose width gradually increases from the narrowed end 32. It looks like this. In this embodiment, as can be seen from FIG.
The overall shape is triangular, and it is constructed by applying a conductive foil, such as aluminum foil, to one side of a flexible synthetic resin sheet such as vinyl chloride.

A reinforcing plate 34 made of a conductive material, for example a thin copper plate, is attached to the narrowed end 32 of the sheet-like conductor means 30, and a lip means 36, such as an alligator, is connected thereto.

The sheet-like conductor means 30 is housed in a wound state within the hollow conductor member 14, with its narrowed end 32 extending over the hollow conductor member 1.
4 (FIG. 1). To explain in detail, hollow conductor member 1
4 is provided with a winding means 38 (FIG. 2) for winding up the sheet-like conductor means 30, and this winding means 38
is composed of a winding tubular member 42 rotatably mounted on the tubular member 20 via a bearing 40.

One side of the triangular sheet-like conductor means 30, that is, the bottom side with the narrowed end 32 as the apex angle, is fixed to the winding tubular member 42, and the sheet-like conductor means 30 is
0 will be wound onto the winding tubular member 42. In FIG. 2, the sheet-like conductor means 30 wound up on the winding tubular member 42 is shown by a broken line. In short, the sheet-like conductor means 30 has its narrow end 3
2 into a winding tubular member 42 for withdrawal through the elongated slot 18 of the projection 16.

The grounding conductor structure according to the present invention also includes an electrical connection means for ensuring electrical connection between the retractable sheet-like conductor means 30 and the hollow conductor member. The connecting means is the protrusion 1 of the hollow conductor member 14.
The conductive plate spring element 44 is provided inside a long slot 18 formed in the conductor plate 6 . Specifically, as shown in FIG.
It is formed, for example, as a plate spring piece made of copper, which is attached at an appropriate interval to the inner surface of one of a pair of extension parts integrally extended from. In this case, it goes without saying that the inner surface of one of the pair of extensions is selected to face the conductor foil side of the sheet-like conductor means 30. These conductive leaf spring elements, ie, the copper leaf spring pieces 44, are always maintained in contact with the conductive foil of the sheet-like conductor means 30 by their spring action, so that the electrical connection between the hollow conductor member 14 and the sheet-like conductor means 30 is maintained. This will ensure a reliable connection. In this embodiment, a conductive leaf spring element 44 is used as the electrical connection means, but other suitable conductive elements, such as conductive brush elements made of thin copper wire, may also be used.

In this embodiment, the winding means 38 includes a winding tubular member 4
A manual winding mechanism 46 is provided to impart rotational movement to the hollow casing 12 , and the manual winding mechanism 46 approaches one end side of the hollow casing 12 , that is, the end side where the connector 26 is provided. It includes a hand crank 48 mounted thereon. As seen in FIGS. 2 and 3, a shaft portion 50 extends from the center of the disc-shaped portion of the hand crank 48, and this shaft portion 50 passes through the hollow casing 12 and the hollow conductor member 14. However, a gear 52 is attached to its tip. As best shown in FIG. 3, gear 52 is engaged with toothing 54 on the end edge of winding tubular member 42 so that hand crank 48 is rotated by its knob 56. Then, the rotational motion is transmitted to the winding tubular member 42.

In this embodiment, the winding means 38 includes a manual winding mechanism 4.
8 is provided, but instead of this manual winding mechanism 48, an elastic mechanism is provided which acts to elastically rewind the sheet-like conductor means 30 to its original winding position when the sheet-like conductor means 30 is pulled out. A target rewinding mechanism may also be provided.

Specifically, such an elastic unwinding mechanism may be constructed of an elastic rubber or a mechanical spring, and the elastic rubber or mechanical spring causes the winding tubular member 42 to rotate when the sheet-like conductor means 30 is pulled out. It is incorporated into the winding tubular member 42 so that the amount of rotation can be stored as an amount of elastic deformation when it is rotated. In short, when the sheet-like conductor means 30 is pulled out with an appropriate pulling force,
The elastic unwinding mechanism undergoes elastic deformation in accordance with the amount of the pull-out, and then when the pull-out force is released, the sheet-like conductor means 30 is automatically rewound to the original winding position by the elastic deformation. become. In this case, it is necessary to make the spring force of the elastic rewinding mechanism smaller than the pinching force of the clip means 36 so that the clip means 36 does not come off due to the spring force when a signal is detected.

Next, main modified embodiments of the embodiment described above will be explained.

First, in the embodiment described above, as an electrical connection means for reliably guaranteeing the electrical connection between the sheet-like conductor means 30 and the hollow conductor element 42, the conductor foil of the sheet-like conductor means 30 is directly connected. The conductive leaf spring element 4 comes into contact with
4 or conductor brush elements have been used, however, a capacitive connection may also be formed between the sheet-like conductor means 30 and the hollow conductor element 42. In this case, the sheet-like conductor means 30 is composed of a pair of flexible synthetic resin sheets and a conductor foil sandwiched between the pair of flexible synthetic resin sheets, while the electrical connection means is configured as an electrode plate, which electrode plate is formed by a pair of extensions integrally extending from the hollow conductor member 14 to form the protrusion 16 of the hollow conductor member 14.

In another variant embodiment, the width of the flexible synthetic resin sheet of the sheet-like conductor means 30 may be made somewhat wider than its conductor foil, thereby leaving an electrically insulating area of the sheet-like conductor means 30. good. In such an embodiment, short-circuit problems that can be caused by the sheet-like conductor means 30 during signal detection will be avoided.

〔Effect of the invention〕

As is clear from the above description, in the grounding conductor structure according to the present invention, since the sheet-like conductor means can be wound up freely, the width of the sheet-like conductor means gradually increases from the narrow end on the drawer side. Because of this, it is possible to minimize the impedance of the sheet-like conductor means during signal detection, and therefore signal measurement with less measurement error can be performed.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a signal measuring device incorporating a grounding conductor structure according to the present invention, Fig. 2 is an enlarged longitudinal cross-sectional view of the signal measuring device shown in Fig. 1, and Fig. 3 shows the manual winding mechanism in detail. It is a partially enlarged perspective view shown. 10...Signal detector, 12...Hollow casing, 14...Hollow conductor member, 16...Protrusion part,
18... Long slot, 20... Tubular member, 22
...Measuring probe, 30... Sheet-like conductor means, 32... Narrowed end, 38... Winding means, 4
2... Tubular member for winding, 44... Conductor leaf spring element, 46... Hand-crank winding mechanism, 48... Hand-crank crank, 52... Gear. 3632 Fig. 1 Vertical cross-sectional view of the signal measuring device shown in Fig. 1 Fig. 2

Claims (1)

[Claims] 1. A grounding door structure used in a signal detector for detecting signals from electronic devices such as ICs, which comprises a flexible sheet-like conductor means (30) and the sheet. The sheet-like conductor means is provided with a winding means (38) for retractably winding the sheet-like conductor means, and the sheet-like conductor means has a narrow end (38) as a grounding connection end.
2), and the width of the sheet-like conductor means gradually increases from the narrow end, and the sheet-like conductor means is wound around the winding means so that it can be pulled out from the narrow end side. , further, the sheet-like conductor means (44
) a grounding conductor structure comprising an electrical connection means fixed in position so as to be able to make an electrical connection to the earth. 2. In the grounding conductor structure according to claim 1, the sheet-like conductor means (30) is made of a flexible synthetic resin sheet and a conductor foil applied to one surface of the flexible synthetic resin sheet. A grounding conductor structure characterized in that the electrical connection means comprises a sliding contact (44) adapted to make direct electrical contact with the conductor foil of the sheet-like conductor means. 3. In the grounding conductor structure according to claim 2, the width of the flexible synthetic resin sheet of the sheet-like conductor means (30) is somewhat wider than the width of the conductor foil, so that the width of the flexible synthetic resin sheet of the sheet-like conductor means (30) is somewhat wider than the width of the conductor foil. A grounding conductor structure characterized in that electrically insulating areas are left on both side edges of the grounding conductor structure. 4. In the grounding conductor structure according to claim 1, the sheet-like conductor means (30) is sandwiched between a pair of flexible synthetic resin sheets and the pair of flexible synthetic resin sheets. 1. A grounding conductor structure comprising a conductor foil, wherein the electrical connection means is constructed as an electrode element that makes a capacitive connection to the sheet-like conductor means.