JPH04236356A - Contact probe - Google Patents

Abstract

PURPOSE:To keep the contact pressure of a probe constant and to bring the probe into contact even with a contact surface different in height by definite propelling force by directly driving the probe by an electromagnetic coil. CONSTITUTION:A contact probe is constituted of a housing 2, an electromagnetic coil 1, a probe 3, a spring 4, an insulating spacer 5, an iron core pipe 6 and a lead wire 7. The force acting on the probe 3 is only the reaction force due to the spring 4 when no current is supplied to the electromagnetic coil 1 and the probe 1 does not come into contact with a contact surface 8. When a current is supplied to the electromagnetic coil 1, constant propelling force acts on the iron core pipe 6 to compress the spring 4 to push down the probe 3. The contact pressure at this time becomes almost same to the propelling force because the spring constant of the spring 4 is sufficiently smaller than the propelling force generated by the coil 1 and the reaction, force of the spring 4 can be neglected. By this constitution, the contact probe can come into even with the contact surface different in height by constant propelling force.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to contact probes, and more particularly to contact probes used for electrical inspection.

0002

[Prior Art] As a conventional technology, for example, the US
There is a contact probe described in PAT No. 3,435,168.

A conventional contact probe will be explained in detail with reference to the drawings. FIG. 2 is a sectional view showing a conventional example. The contact probe shown in FIG. 2 has a housing 11 having a hollow cylindrical aperture and a recess in a part, and a stepped part located inside the housing 11 with one end shaped like a sharp needle and a middle part smaller than the outer diameter of both ends. The probe needle 12 includes a conical probe needle 12, a spring 13 in contact with the other end of the probe needle 12, and a ball 14 held between the housing 11 and the spring 13. Here, the probe needle 12 came into contact with the contact surface, pushed the spring 13, pressed the ball 14 against the housing 11, and extracted an electrical signal.

0004

[Problems to be Solved by the Invention] In the conventional contact probe described above, in order to obtain a good connection that breaks the oxide film on the contact surface and does not cause unnecessary scratches, the probe needle must be held under a predetermined load. The probe needle must be pressed against the contact surface, and this load is normally managed so that the amount of push-in of the probe needle is 2/3 of the total push-down amount. Therefore,
When the height of contact with the probe needle differs between test pads, IC leads, solder surfaces, etc., there is a drawback that the amount of movement of the contact probe must be changed for each.

[0005]

[Means for Solving the Problems] A contact probe of the present invention includes: (A) a pipe-shaped housing having a restriction at one end;
B) an electromagnetic coil attached to the outer periphery of the housing;
(C) A needle having one end having a stepped portion slidably guided by the housing and disposed inside the housing on the side having the constriction, and the other end having a sharp protrusion protruding from the housing. , (D) a spring attached to one end of the needle, (E)
a hollow insulating spacer inserted into the housing so as to be in contact with the stepped portion of the needle; (F) an iron core pipe located within the housing and fixed to the insulating spacer; (G) a stepped portion of the needle. and a lead wire connected to the insulating spacer and the hollow portion of the iron core pipe to the outside from the other end of the housing.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to the drawings.

FIGS. 1(a) and 1(b) are cross-sectional views showing one embodiment of the present invention. The contact probe shown in FIGS. 1(a) and 1(b) includes: (A) a pipe-shaped housing 2 having a restriction at one end;
(B) Electromagnetic coil 1 attached to the outer periphery of the housing 2
, (C) A needle whose one end with a stepped part that is slidably guided in the housing 2 is arranged inside the housing 2 on the side having the constriction, and whose other end with a sharp projection protrudes outside the housing 2. 3. (D) Spring 4 attached to one end of needle 3. (E)
(F) A hollow insulating spacer 5 inserted into the housing 2 so as to be in contact with the stepped portion of the needle 3; (F) A core pipe 6 located within the housing 2 and fixed to the insulating spacer 5; (G) A step of the needle 3. A lead wire 7 is connected to the attached portion, and is led out from the other end of the housing 2 through the insulating spacer 5 and the hollow portion of the iron core pipe 6.

FIG. 1(a) shows the state before operation, and since the electromagnetic coil 1 is not energized, the force acting on the needle 3 is only the reaction force caused by the spring 4, and the needle 3 does not come into contact with the contact surface 8. Figure 1(b) shows the state after operation, and the electromagnetic coil 1
When energized, a constant thrust F acts on the core pipe 6, compressing the spring 4 and pushing down the needle 3. The contact pressure at this time is that the spring constant k of the spring 4 is equal to the electromagnetic coil 1.
Spring 4 is sufficiently small compared to the thrust F generated by
The reaction force f can be ignored and is almost the same as the thrust force F. Also,
The electrical signal is taken out directly from the lead wire 7 connected to the needle 3 which is insulated by the iron core pipe 6 and the insulating spacer 5.

[0009]

[Effects of the Invention] The contact probe of the present invention directly drives the movement of the needle with an electromagnetic coil, so that the contact pressure of the needle remains constant at any position in the stroke, so a constant thrust is applied to contact surfaces of different heights. Since contact is possible, there is an advantage that there is no need to change the amount of movement of the contact probe in response to the height of the contact surface.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are cross-sectional views showing one embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional example.

[Explanation of symbols]

1 Electromagnetic coil 2 Housing 3 needle 4 Spring 5 Insulating spacer 6 Iron core pipe 7 Lead wire

Claims (1)

[Claims] 1. (A) a pipe-shaped housing having a throttle at one end; (B) an electromagnetic coil attached to the outer periphery of the housing; (C) one end having a stepped portion slidably guided by the housing. , (D) a spring attached to one end of the needle, (E) a needle disposed inside the housing on the side having the aperture, the other end having a sharp protrusion protruding from the housing; (D) a spring attached to one end of the needle; (F) a hollow insulating spacer inserted into the housing so as to be in contact with the stepped portion of the needle; (F) an iron core pipe located within the housing and fixed to the insulating spacer; (G) a hollow insulating spacer inserted into the stepped portion of the needle; A contact probe, comprising: a lead wire connected to the insulating spacer and the hollow portion of the iron core pipe, and led out from the other end of the housing.