JP2624457B2 - Contact pin deformation detection mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the deformation of a contact pin by judging the state of contact between an IC lead and a contact pin in an IC socket in which the IC is mounted when measuring electrical characteristics. Regarding the mechanism.

[0002]

2. Description of the Related Art A conventional IC socket has a socket body having a recess into which an outer package of an IC is inserted, and is arranged side by side around the socket body so that one end extends through the socket body and the other end extends toward the recess side. And a plurality of contact pins for making the tip end contact the IC lead.

[0003] These contact pins have the same number as the leads of the IC. For example, they are arranged at a narrow pitch of about 0.65 mm and are buried around the socket body. It is partitioned. In addition, the contact pins ensure contact with the leads of the IC due to the resiliency of the curved portions of the contact pins.

[0004]

In a conventional IC socket, the number of contact pins is several tens to several in accordance with the lead pitch of the IC.
It has a thickness of only over a hundred tens of μm,
If the package pushes the contact pins,
There is a problem that the contact pin is plastically deformed due to a long-term repetitive stress applied to the curved portion of the contact pin by a foreign substance entering between the lead of C and the contact pin, so that the contact pin does not come into contact with the lead.

[0005] The poor contact with the leads of the IC due to the deformation of the contact pins does not indicate whether the electrical characteristic test is normally performed or not, and often leads to a large number of apparently good or defective products until the test abnormality is noticed. Will occur. For this reason, there has been a problem that the test has to be performed again and wasteful man-hours are consumed.

As a countermeasure, a method of making the socket body transparent and observing the contact state between the contact pins and the leads of the IC visually beforehand can be considered. One contact state of the contact pins arranged at a fine pitch can be considered. Observation at a time is practically difficult. In addition, many holes corresponding to the contact pins are drilled at the bottom of the recess of the socket body,
An inspection method can be considered based on whether there is continuity between the probe pin passing through these holes and one end of the contact pin derived from the socket body. In addition to this, the provision of a large number of probe pins, such as 100 pins and 200 pins, complicates the structure and becomes expensive, so this is not an advantageous method.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an inexpensive IC having a very simple structure and a reliable test by judging the quality of contact between a contact pin and a lead of an IC socket.
An object of the present invention is to provide a socket contact pin deformation detecting mechanism.

[0008]

SUMMARY OF THE INVENTION A feature of the present invention is that a socket body having a recess into which an outer package of an IC enters is provided, and is arranged side by side around the socket body, one end of which penetrates the socket body, and the other end of which is connected to the socket body. A contact pin deformation detecting a deformation of the contact pin that causes a contact failure between the lead and the contact pin of an IC socket having a plurality of contact pins having a plurality of contact pins that are bent so as to extend toward the dent side and contact the tip end thereof with the lead of the IC. In the detection mechanism, a plate-shaped conductive plate laid on the bottom of the depression, and a conductive wire derived from the socket body from the conductive plate,
When the outer body is inserted into the recess with the IC, the tip of the contact pin at the time of energization contacts the lead and the tip is pushed down to determine whether or not the tip comes into contact with the conductive plate or whether the conductive A contact pin deformation detection mechanism comprising: a deformation detection circuit that determines whether or not the contact pin is deformed based on whether a gap between a plate and the tip portion is equal to or smaller than an allowable value. Further, it is preferable that an abnormality display unit is provided for displaying an abnormality by a signal indicating that the contact pin is deformed by the deformation detection circuit.

Further, another feature of the present invention is an IC socket including the contact pin deformation detecting mechanism.

On the other hand, a deformation detecting circuit for judging the presence or absence of deformation of the contact pin based on whether or not the tip end of the contact pin is in contact with the conductive plate is provided. Is characterized by the presence or absence of a voltage applied to the. Further, a deformation detection circuit that determines whether or not the contact pin is deformed by determining whether a gap between the distal end portion of the contact pin and the conductive plate is equal to or smaller than an allowable value, includes: It is characterized in that it is determined whether or not the electric charge induced in the conductive plate by the electric field is equal to or more than a specified value.

[0011]

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

FIGS. 1A and 1B show an IC for explaining a contact pin deformation detecting mechanism according to an embodiment of the present invention.
It is the sectional view of a socket, and the circuit diagram of a detection circuit. This contact pin deformation detecting mechanism is, as shown in FIG. 1A, a plate-shaped conductive plate 3 laid on the bottom of the depression 9 of the socket body 8 and is derived from the socket body 8 from the conductive plate 3. The one conductive wire 4 and the outer body 7 of the IC are put into the recess 9, and the tip 5 a of the contact pin 5 presses the lead 6, and the contact pin 5 is deformed depending on whether the tip 5 a does not contact the conductive plate 3. A detection circuit 1 for determining the presence / absence of a defect, and an abnormality display section 2 for displaying that there is a contact failure between at least a pair of contact pins 5 and the leads 6 by an output indicating that the detection circuit 1 is deformed.

Normally, the lead 6 of the IC is in contact with the contact pin 5 at a normal position indicated by a two-dot chain line, but plastically deforms due to fatigue while repeating the measurement several times. In this case, the lead 6 and the tip 5a of the contact pin 5 are separated from each other by a distance c and do not come into contact with each other. Utilizing this, IC
If the installation position of the conductive plate 3 is set in consideration of the amount h of the spring of the bending portion and the amount c of depression, the amount of pushing the outer body 7 into the depression 9 is reduced by c due to fatigue or any other reason. The contact pin 5 has its tip 5a not in contact with the lead 6 but in contact with the conductive plate 3, and it is easy to determine whether or not the tip 5a of the contact pin 5 is in contact with the conductive plate 3. It is possible to detect whether or not the contact pin 5 is deformed.

The detection circuit 1 for determining whether or not the contact pin 5 and the conductive plate 3 have come into contact with each other, for example, as shown in FIG.
As shown in (b), when the contact pin 5 contacts the conductive plate 3 without contacting the lead 6, that is, when there is a deformation, the voltage applied to the contact pin 5 (for example,
3.5V) is input to the comparator via the conductive line 4,
Compared with the reference voltage Vdd (for example, 5 V), the difference between the output of the comparator and the reference voltage becomes Low (1.5 V). Then, High (5 V) is applied by a flip-flop.
Becomes As a result, the abnormality display unit 2 is driven by the High-level output voltage of the flip-flop. The abnormality display unit 2 may be, for example, a light emitting diode.

Conversely, when the contact between the contact pin 5 and the lead 6 is normal and does not contact the conductive plate 3, the input voltage from the conductive plate 3 is zero and the output voltage of the comparator is Hi.
gh, the voltage of the flip-flop becomes Low, and the abnormality display unit 2 does not operate.

At the beginning of a test program for such a detection circuit 1 and a tester, a test item for determining whether or not a test can be started is provided.
When a voltage lower than the reference voltage is applied to all of the contact pins 5 when the
If even one of the contact pins 5 is in poor contact, the abnormality display section 2 operates and the test is not started. This determination can be made in a fraction of a second. If the test can be started, the test proceeds according to the program. Moreover, whether this test can be started
Since the selection can be performed for each IC loaded in the IC socket, selection errors due to poor contact do not occur.

FIG. 2 is a circuit diagram showing another embodiment of the detection circuit of FIG. Also, as described above, the contact pin 5
Due to the fatigue, there is often a gap C1 between the lead 6 and the tip portion 5a of the contact pin 5 without contact with the lead 6 and a gap C2 without contact with the conductive plate 3 in many cases. In such a case, it is seen in the initial state of the deformation, and eventually becomes the state of the aforementioned embodiment.
This means that the above-mentioned detection circuit does not detect the degree of deformation, and there is a possibility that the degree of deformation may be overlooked.

Therefore, in the present invention, the position of the conductive plate 3 is adjusted so that the gap C1 is reduced, and the amount of electric charge of the conductive plate 3 induced by the electric field of the contact pin 5 when energized is detected. The fifth embodiment focuses on detecting the deformation of the fifth embodiment. That is, for example, as shown in FIG.
A Wheatstone bridge with an impedance including a capacitor, an oscillation circuit for driving the impedance bridge, an operational amplifier for receiving the output of the bridge and outputting a voltage difference between the output, and a high level for receiving the output of the operational amplifier.
Alternatively, it is configured by a flip-flop that outputs a Low level voltage.

Here, the position of the conductive plate 3 is set so as to reduce the gap C 2, and a charge capacity of at least several picofarads or more is induced by the voltage of the contact pin 5. If necessary, the voltage may be increased, and the contact pin 5 on the side not in contact with the lead 6 may be made of a high dielectric material. When the contact between the lead 6 and the contact pin 5 is normal and the gap C2 is large and the amount of charge induced in the conductive plate is small, it is necessary to adjust the capacity of the variable capacitor so that the balance of the Whiston bridge circuit is not lost. is there.

The operation of detecting the deformation of the contact pin 5 by the detection circuit 1 prepared as described above is as follows. First, when the gap between the tip 5a of the contact pin 5 and the conductive plate 3 becomes smaller than the gap C2, the electric charge is accumulated on the conductive plate 3. Charge is increased, the balance of the Whiston bridge is lost, and e
The voltages of 1 and e2 are input. This operational amplifier operates as a subtractor, and the output is e2-e1. Then, a high-level voltage equal to the reference voltage Vdd is output by the flip-flop. Then, the abnormality display section of FIG. 1 is operated with this output voltage.

The lead 6 and the contact pin 5
When the contact is made, the gap of C2 is large, the amount of electric charge induced in the conductive plate 3 is small, and the Wheatstone bridge does not lose its balance. Part 2 does not work. The mechanism for detecting the deformation of the contact pin due to the change in capacitance due to the gap C2 has an advantage over the above-described voltage-based detection mechanism that it can detect even the initial slight deformation of the contact pin 5 that causes a contact failure.

[0022]

As described above, according to the present invention, one flat conductive plate is provided with a gap between the contact pins and the contact pins corresponding to the plurality of contact pins of the IC socket which is in contact with the IC leads and is pressed down. , IC before measurement
Is mounted in an IC socket and a detection circuit is provided to detect whether or not there is contact between the contact pin and the conductive plate and to determine whether or not the contact pin is deformed by detecting whether or not the contact pin is deformed. By detecting the deformation as soon as possible, it is possible to detect a defect in contact with the lead of the IC.
There is an effect that a reliable test can be performed without the necessity of reselecting the electrical characteristic test.

Further, since only one conductive plate having a simple structure and a simple detection circuit are required, there is an effect that the cost can be obtained at a low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of an IC socket and a circuit diagram of a detection circuit for explaining a contact pin deformation detection mechanism according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the detection circuit of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detection circuit 2 Abnormal display part 3 Conductive plate 4 Conductive wire 5 Contact pin 5a Tip part 6 Lead 7 Outer body 8 Socket body 9 Depression

Claims (5)

(57) [Claims] 1. A socket body having a recess into which an outer body of an IC enters, and a socket body arranged and arranged around the socket body, one end of which penetrates the socket body, and the other end of which is curved so as to extend toward the recess side and has a tip end. A contact pin deformation detecting mechanism for detecting a deformation of the contact pin that causes a contact failure between the lead and the contact pin of an IC socket having a plurality of contact pins for contacting a portion with the lead of the IC. A plate-shaped conductive plate, a conductive wire led out of the socket body from the conductive plate, and a tip of the contact pin when the IC is put into the recess and the outer pin is put in contact with the lead when energized. Whether the tip is pushed down and the conductive plate comes into contact with the tip or not, or the gap between the conductive plate and the tip is an allowable value A deformation detection circuit for determining whether or not the contact pin is deformed based on the following conditions: 2. The contact pin deformation detecting mechanism according to claim 1, further comprising: an abnormality display section for displaying an abnormality by a signal indicating that the contact pin is deformed by the deformation detecting circuit. 3. An IC comprising the contact pin deformation detecting mechanism according to claim 1 or 2.
socket. 4. A deformation detecting circuit according to claim 1, wherein said deformation detecting circuit determines whether or not said contact pin is deformed by contacting said tip portion with said conductive plate. A contact pin deformation detection mechanism, wherein the determination is made based on the presence or absence of a voltage applied to the conductive plate based on a voltage. 5. The deformation detection circuit according to claim 1, wherein the deformation detection circuit determines whether the contact pin is deformed based on whether a gap between the tip portion of the contact pin and the conductive plate is equal to or smaller than an allowable value. A contact pin deformation detecting mechanism for determining whether the electric charge induced in the conductive plate by the electric field of the contact pin at the time of energization is equal to or greater than a specified value.