JPH09145765A - Method and device for reproducing and testing migration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely reproduce migration in a short time by condensing steam generated by heating a closed pressure vessel which supports objects to be tested after pouring water in the container into dews on the surfaces of the objects. SOLUTION: While posistors 10 to be tested are supported in, for example, the main body 2 of a stainless steel closed pressure container and steam is generated by heating a prescribed amount of water 40 contained in the main body 2 with a heater 11 so that dews can be forcibly condensed on the surfaces of thermistor (TPC) elements in the posistors 10 and migration can be reproduced. At the time of conducting migration tests, the temperatures of the posistors 10 rise to about 140 deg.C or higher, because rated voltages are applied across current introducing terminals 9, but the condensed dews continuously adhere to the posistors 10, because the posistors 10 are maintained in a steam atmosphere. Since the temperature in the container 1 is controlled with a thermocouple 7 and the steam pressure in the container 1 is controlled with a pressure gauge 8, tests can be conducted under a prescribed condition for a prescribed period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a migration reproduction test method and an apparatus therefor, for example, a positive temperature coefficient thermistor PTC (Positor) called a posistor.
TECHNICAL FIELD The present invention relates to a method and apparatus for reproducing a migration that may occur in a PTC element (hereinafter, also referred to as a PTC thermistor) in an electrical component having a built-in tive temperature coefficient (Coefficient Thermistor) element.

[0002]

2. Description of the Related Art In a color television picture tube,
The three primary colors (red, green,
The electron beam emitted at high speed from the (blue) electron gun is selectively incident on the phosphors which are regularly arranged and coated on the inner surface of the face plate of the picture tube, and the corresponding phosphors are caused to emit light. Color images can be obtained.

However, due to the incidence of electrons emitted as described above, the inner surface of the face plate becomes magnetized, and this magnetism remains and accumulates in the fluorescent film during the reception of the image on the television. John screen is easily magnetized. Due to the influence of this residual magnetism, the electron beam emitted from the electron gun does not land correctly on the target fluorescent body position, causing color unevenness on the television screen.

FIG. 14 shows a state where color irregularities 46A and 46B appear on the screen 45a of the television receiver 45 due to such a phenomenon. Such color unevenness is not uniform,
There are various shades, areas, places, etc., and they occur inevitably.

Therefore, as a countermeasure for this, for example, as shown in FIG.
As shown in FIG. 15, a degaussing coil 43 is provided on the outer surface of the funnel portion 42 of the picture tube 45 to eliminate the residual magnetism in the screen as described above.

For this purpose, the degaussing coil 43 described above is provided by a posistor, which will be described later, provided with a PTC element 26 as shown in FIG.
And is attached in the vicinity of the picture tube 45. That is,
A degaussing circuit as shown in FIG. 13 is configured to eliminate residual magnetism and remove color irregularities 46A and 46B (in this figure, the DGC (De-Gauss Coil) is the above degaussing coil).
Represents 43).

In order to demagnetize the residual magnetism on the fluorescent material in this way, as shown in FIGS. 13 and 14, the switch SW of the power supply 44 of the television receiver 45 is turned on and, at the same time, the PTC of the posistor is turned on. A large current is momentarily passed through the degaussing coil 43 through the element 26, and the reverse magnetic field generated thereby cancels the residual magnetism and degausses it.

This instantaneously flowing electric current is a large electric current of 3 to 4 A or 7 to 8 A, though it depends on the type of television equipment. Since heat generated by such a large current easily causes the picture tube of the television to become hot, it is necessary to immediately reduce the large current to a minute current of several mA to prevent heat generation.

Therefore, it is necessary to supply the necessary large current to the degaussing coil 43 and immediately cut off or significantly reduce the current immediately after the supply, which is caused by the PTC element 26 of the posistor described above. It is possible.

That is, FIG. 12 shows the temperature characteristic of the resistance of this posistor, whereas the characteristic 39 of a general thermistor decreases as the temperature rises, whereas the characteristic 38 of the PTC thermistor decreases. In this case, the resistance value, which is less than 50 Ω at room temperature, rises sharply as the temperature rises, and reaches about 10 ⁸ Ω at about 200 ° C. In the process of this temperature rise, almost 120 ℃
The operating temperature of the posistor is in the temperature range between 150 ° C and 200 ° C, and the resistance of the posistor is as large as 10 ⁶ to 10 ⁸ Ω at the temperature T in this temperature range, and almost no current flows.

The operating temperature of the posistor is that the posistor itself is a heating element having a resistance value. Therefore, after the power is turned on, a large current is passed through the degaussing coil 43 through the posistor to erase the above-mentioned residual magnetism. At the temperature of self-heating, the resistance of the posistor becomes remarkably large, the current is automatically cut off or drastically reduced, and the circuit is cut off to prevent further temperature rise. Then, when the temperature reaches 200 ° C, a large current is cut off by the posistor.

Therefore, the posistor is an indispensable component for removing the color unevenness of the television screen, but if it does not have the ability to sufficiently cut off the current after degaussing, the current will flow too much and the television May cause smoke or fire accidents.

That is, if silver, which is an electrode material provided on both sides of the PTC element 26 in the posistor, migrates to cause a short circuit phenomenon, the current is not interrupted even at the operating temperature of the posistor. , The above accident may occur.

It is considered that the main cause of silver migration is that silver hydroxide (AgOH) is produced by the action of moisture (OH ions) in the air, as described in the following items.

Due to the presence of a high temperature atmosphere and a potential difference, silver on the electrodes and moisture on the surface of the insulating material on which the electrodes are provided are
Ionization occurs as in g → Ag ⁺ , H ₂ O → H ⁺ + OH ⁻ , and it becomes easy to move to the counter electrode side.

Ag ⁺ and OH ⁻ form and precipitate silver hydroxide (AgOH) in a region near the anode.

AgOH decomposes and decomposes in the anode region

Embedded image Like silver oxide, which grows by electrochemical migration.

After that, by the reducing substance in the insulating material,

Embedded image In the case of the above process, the migration of Ag ⁺ causes the metal Ag to grow in the cathode region by electrochemical migration.

In order to prevent such electrochemical migration of silver, it is necessary not to give water between the silver electrodes on both sides, but this is due to OH ions in the air. It is impossible and there is no definitive preventive measure.

Therefore, since the influence of moisture in the air is unavoidable, in order to prevent the above-mentioned ignition accident and the like, how much migration progresses under what conditions and conditions such as temperature and humidity. In anticipation of moisture migration due to moisture over a long period of time, an accelerated deterioration test under high temperature and high humidity under conditions corresponding to this in advance should be performed, and the result should be used as a guideline for the product. It becomes an important matter in quality control.

For this purpose, a test for reproducing the migration of the silver electrode in the posistor under various conditions is indispensable, but a reliable test method has not been established so far.

In order to reproduce the cause of migration, it is sufficient to apply the dew condensation or humidity which is the source of the OH ion, and for the evaluation test of this, the dew condensation and humidity are efficiently adjusted so that acceleration can be obtained. It is important to stably apply to. However, in reality, the operating temperature of the PTC element in the posistor is generally as high as 140 ° C or higher, so that even if condensation or humidity is applied, it vaporizes instantly, and it is difficult to accelerate and apply OH ions. Met.

For example, the following migration reproducibility tests have been generally attempted and the results thereof are as follows.

After the posistor is cooled in a low temperature tank, it is immediately placed in a high temperature and high humidity tank to be energized while dew condensation occurs (however, this energization corresponds to the energization during actual use of the posistor).

However, this has an unstable factor that the amount of dew condensation fluctuates depending on the movement speed of the posistor between the tanks and the environment. In addition, only one moment of dew condensation can be obtained with one movement between tanks,
Not suitable for accelerated tests.

Electric power is supplied by spraying steam with a sprayer.

In this case, since the surface of the element was as high as 140 ° C. or higher, it was instantly evaporated and it was impossible to cause dew condensation.

It is placed in a high temperature and high humidity tank and energized.

It was impossible to cause dew condensation for the same reason as above.

[0030]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and it causes stable and reliable dew condensation on an object to be tested, and maintains the dew condensation. It is an object of the present invention to provide a migration reproduction test method and a device therefor capable of accelerating migration to a DUT by this dew condensation and realizing it in a short time and with high reliability.

[0031]

As a result of intensive studies to achieve the above object, the present inventor has focused on exposing a test object to water vapor in a closed container, and further Water is put in the container and the heater is used to heat the container to forcibly generate steam. Furthermore, by holding the DUT in the steam atmosphere in the container so that it can be energized, the DUT is condensed. The present invention has been reached based on the conclusion that migration can be reproduced reliably in a short time.

That is, according to the present invention, a reproduction of migration is performed in which an object to be tested is supported in a container which can be sealed, and dew condensation is caused on the object to be tested, and the dew condensation causes migration to the object to be tested. It relates to the test method.

Further, the present invention is provided with a container which can be sealed, a supporting means for supporting the object to be tested in the container, and a means for imparting dew condensation to the object to be tested,
The present invention also relates to a migration reproduction test apparatus configured to generate migration in the DUT.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION In the migration reproduction test method according to the present invention, the object to be tested is supported in a high temperature pressure vessel so that it can be energized, and the water in the high temperature pressure vessel is evaporated by heating, and this steam is removed. It is desirable to provide a sealing means in the high temperature pressure vessel so that the water vapor does not leak to the outside of the high temperature pressure vessel by causing dew condensation on the DUT.

It is desirable that the object to be tested is supported in the container and tested at a predetermined temperature and a predetermined vapor pressure for a predetermined time.

It is desirable to change at least one of the amount of water and the heating energy with respect to the inner volume of the container.

Furthermore, the internal temperature of the container is set to be equal to or higher than the operating temperature during actual use of the DUT, and the humidity in the container is 40% to 40%.
It is desirable to set the saturated vapor pressure and the test time to 1 minute or more.

The above-mentioned test method is a method suitable for testing, for example, a posistor used in a degaussing circuit of a cathode ray tube, using a posistor as an object to be tested.

Further, in the migration reproduction test apparatus according to the present invention, a supporting means for supporting the DUT so that the DUT can be energized and a high temperature pressure container for accommodating the DUT are heated. Heating means to
It is desirable that a water vapor generation unit that evaporates water in the high temperature pressure container and condenses the water vapor on the DUT, and a sealing unit that prevents the water vapor from leaking out of the high temperature pressure container are provided. .

Further, it is desirable that temperature detection means for detecting the temperature inside the container and pressure detection means for detecting the pressure inside the container are provided.

Further, the means for supporting the object to be tested has a current introducing terminal body screwed and fixed to the container, and the current conducting wire is airtightly supported by the insulating powder pressed into the current introducing terminal body. It is desirable to be configured as follows.

The above-mentioned device is a device suitable for supporting a posistor as an object to be tested in a container and for reproducing a migration between electrodes of a posistor used for a degaussing circuit of a cathode ray tube.

[0043]

Embodiments of the present invention will be described below in detail.

FIG. 1 is a sectional view showing a state in which a posistor is supported in an airtight container used in an embodiment in which the present invention is applied to a migration reproduction test of a posistor.

As shown in FIG. 1, in this migration reproduction test method, a posistor 10 is supported in a sealable container 1 (for example, a pressure-resistant closed container made of stainless steel) configured as an autoclave body, and migration acceleration is performed on this. This causes dew condensation. That is, as a means for imparting dew condensation, if a predetermined amount of water 40 is stored in the container 1 in advance and the water is heated to generate steam in the container 1, the container 1 can be filled with steam. Condensation can be forcedly generated on the PTC element 26 (see FIG. 5 described later) in the posistor 10 which is the DUT.

In this case, since the rated voltage is applied to the posistor 10 from the outside through the current introduction terminal 9, the temperature rises to 140 ° C. or higher, but since the posistor 10 is in the vapor atmosphere in the closed container 1, Moisture due to the generated dew condensation continues to adhere to and cover the posistor 10. Then, the temperature and vapor pressure inside the container 1 are controlled by an instrument provided outside the container 1, and a test can be performed under a predetermined condition for a predetermined time.

In FIG. 2, the heater 11 is arranged around the closed container 1 supporting the posistor 10 as described above.
Autoclave 21 that can heat container 1 to a specified temperature by
FIG.

A lid 3 is provided on the upper portion of the main body 2 of the container 1, a packing 4A is arranged between the main body 2 and the lid 3, and the lid 3 is fastened and fixed to the main body 2 with bolts 5. The main body 2 has a heater 11 having a heater wire 12 provided therein.
Surrounded by the sides and bottom by, it is structured to be heated.

A concave portion 13 is provided on the outer surface of the heater 11, and a thermocouple 14 is arranged in the concave portion and its lead wires 14a and 14b.
Is connected to a voltmeter (not shown) to detect the heater temperature and control its power. On the other hand, a thermocouple case 6 is also welded to the lid 3 of the container 1 by being welded to the inside of the lid 3 so as to project downward inside the container 1, and a thermocouple 7 is arranged therein and its lead wires 7a, 7b are provided. Is through hole 3
It is connected to a voltmeter (not shown) through a and detects the internal temperature of the container 1.

Therefore, the thermocouple 14 is for controlling the heating temperature of the main body 2 of the container 1, and the other thermocouple 7 is used.
Is for measuring the temperature inside the container 1. Then, the test can be performed by adjusting the heating amount of the heater 11 to bring the internal temperature of the container 1 to a predetermined temperature based on the both measured temperatures.

A pressure gauge 8 is provided on the lid 3.
The conduit 8a penetrates the lid 3. Then, the water 40, which is stored in an appropriate amount at the bottom of the main body 2 in accordance with the test conditions, is heated by the heater 11 to be steamed, and the steam pressure is measured by the pressure gauge 8.

The lid 3 is provided with a plurality of screw holes 3b, and the current introducing terminals 9 are respectively screwed and fixed in these holes. The current conducting wire 17 supported by the current introducing terminal 9 is guided into the container 1, and the posistor 10 is attached to the tip thereof.
Are connected and held. Therefore, when testing the posistor, first, with the lid 3 removed from the body 2,
The posistor 10 is connected to 17, and a predetermined amount of water 40 is injected into the main body 2, and then the lid 3 is put on the main body 2 and fixed by the bolt 5.

FIG. 3 is a cross-sectional view showing another embodiment of the present invention. Compared with the device shown in FIG. 2, a single posistor is used.
It is configured as a device (autoclave) 31 for testing 10.

In this case, except for the number of objects to be tested, the same as in the embodiment of FIG. 2, so the description of each part is omitted here. It should be noted that the apparatus of the embodiment shown in FIG. 2 can also be used for testing, for example, by mounting a single posistor 10.

The current introducing terminal 9 has a structure as shown in FIG. The current introducing terminal 9 is composed of a main body 15, a cap nut 16 and a pressure welding tube 18, and the tip of the main body 15 has a threaded portion 15
a is formed, and a threaded portion 15b is also formed on the other end side so that the threaded portion 16a of the cap nut 16 is screwed. The end surface 15d of the screw portion 15a is tightly sealed to the lid 3 by a packing 4B. The pressure welding tube 18 is the body 15 on the side of the cap nut 16.
And plays a role of press-contacting and solidifying the insulating powder 19 described later.

An insulating material 20 supporting the current conducting wire 17 is fitted into the pawl portion 15c inside the threaded portion 15a of the main body 15, and the current conducting wire 17 is guided to the outside through a hole provided in the cap nut 16. . Then, the current conducting wire 17 penetrates through the insulating material 20 from the side of the posistor 10 and is further fixed in position at the central portion of the insulating powder 19 press-fitted by the pressure welding tube 18 in the main body 15 and led out to the outside. Has been done.

That is, the insulating material 20 supporting the current conducting wire 17 is inserted from the upper portion (outside) of the main body 15, and then the insulating powder 19
After inserting (for example, ceramic powder), the pressure contact tube 18 is inserted, the position of the current conducting wire 17 is determined, and then the cap nut 16 is tightened. Since the flange portion 18a is formed inwardly on the upper portion of the press-contact pipe 18, the insulating powder 19 is pressed against the insulating material 20 and the tapered surface 15c of the main body 15 by tightening the cap nut 16 and inside the main body 15. Compacted and insulating powder 19
Has a shape as shown in FIG.
Fix 17 firmly.

The current introducing terminal 9 having the above-mentioned structure surely insulates and supports the current conducting wire 17 through which a large current flows. Then, the packings 4A and 4B described above and the insulating powder
By 19, the vapor pressure in the container 1 is cut off from the outside air to maintain the airtightness.

The current introducing terminal 9 is screwed into the screw portion provided on the lid 3 of the container 1, and then the posistor 10 shown in FIG. 5 is connected to the tip of the current conducting wire. FIG. 6 shows FIG.
FIG. 3 is an exploded perspective view of the posistor 10 shown in FIG. 1 (however, the nickel base film is not shown).

In the case 41 of the posistor 10, the terminal board 23
PTC element 26 (eg 26A for heater) on one side
Is sandwiched between the terminal plates 24, and the PTC element 26 (for example, demagnetizing 26B) is inserted between the terminal plates 23, 24, 25 on the other side surface. The PTC elements 26A, 26B are pressed against the central terminal plate 23 by elastic contact portions 24a, 25a provided on the terminal plates 24, 25.

On the bottom surface of the case 41, each terminal plate 23, 24, 25
Is provided with a through hole 40 (see FIG. 5) through which the lower part of each of the terminal plates 23, 24, 25 is provided.
24b and 25b are fitted or abutted in the through holes,
Each terminal plate 23, 24, 25 is fixed to the case 41.
In this way, the lid 22 is put on after fixing the terminal plates 23, 24, 25. It should be noted that the corresponding current conductors 17 are connected to the conductor connecting portions 23b, 24c, 25c at the lower ends of the terminal plates 23, 24, 25, respectively.
17b, 17c and 17a are connected.

FIG. 5A is a sectional view of the posistor 10 assembled in this way, and FIG. 5B is a sectional view taken along the line bb of FIG.
It is a line sectional view.

PTC element set in the posistor 10
26 has a shape as clearly shown in the perspective view of FIG. 10, the insulating main body 29 is made of a ceramic such as barium titanate in a disk shape, and silver electrodes are provided on both sides with a nickel base film interposed therebetween.
27A and 27B are formed. Then, this is incorporated into the posistor 10, is mounted in the vicinity of the television picture tube as described above, and constitutes the degaussing coil 43 provided outside the picture tube shown in FIG. 15 and the circuit shown in FIG. doing.

That is, in FIG. 13, a portion surrounded by a broken line is the posistor 10, and of the two PTC elements provided in the posistor 10, one PTC element 26A is for a heater and the other PTC element is a PTC element. Element 26B is for degaussing and corresponds to that shown in FIG. The connection position of each terminal of the posistor 10 in the degaussing circuit is indicated by in FIGS. 5 and 13.

Each of these PTC elements 26A and 26B immediately rises to the operating temperature or higher due to a large current, but in order to maintain the temperature of the PTC element 26B which acts for degaussing, the other PTC element 26A For heater
As shown in FIGS. 5 and 6, the PTC elements 26B are installed back to back, so to speak.

In FIG. 13, when the power supply 44 is turned on, each P
After a large current flows through the TC elements 26A and 26B and the degaussing coil 43, a magnetic field is generated from the degaussing coil 43 to erase the color unevenness on the screen of the television receiver described above. , When the operating temperature of the posistor is raised, P
The resistance of the TC element 26B sharply increases, and the current no longer flows through the degaussing coil 43, so that the operation of this degaussing circuit is stopped.

The posistor 10 used for such a purpose
Cannot be hermetically sealed in the case 41 due to the insertion holes 40 of the terminal plates 23, 24, 25 and the gaps between the respective built-in parts, so that the PTC elements 26A, 26B in the case 41 can be removed from the outside of the posistor 10. OH from water contained in invading air
The ions cause the above-described electrochemical migration. This migration is caused by the PTC element 26A,
Insulation resistance of silver ions from the periphery of the silver electrodes 27A and 27B of 26B 29
This is due to diffusion on the peripheral surface of the electrode, and if this progresses, a short circuit will occur between both electrodes.

Therefore, in the present embodiment, the migration of silver generated in the PTC element of the posistor 10 is artificially caused by the above-mentioned phenomenon in the television receiver after a long time has passed. That is, by creating various extremely harsh conditions in a sealed container so as to be equivalent to a state where a long time has passed, the PTC element in the posistor is surely caused to migrate in a short time, and is forced. Accelerated testing is possible.

According to the present embodiment, the posistor 10 can be exposed to the vapor atmosphere which is high in temperature, high humidity and airtight in the container 21 or 31 supporting the posistor 10, whereby the operating temperature of the posistor 10 or higher or 140 40% ~ under high temperature above ℃
Under the temperature condition of saturated vapor pressure, OH ions can be easily attached to the surface of the PTC element, and dew condensation can be continuously generated.

Since the temperature and the humidity can be arbitrarily changed according to the set conditions, the acceleration coefficient for reproducing the migration can be controlled.

Furthermore, this migration reproduction test
Since it is carried out in an airtight container configured as an autoclave, there are no instability factors, tests can be performed with good reproducibility, and the reliability of the posistor can be evaluated (whether or not migration has occurred).
Can be confirmed in a short time. The time required for the test may be 1 minute or more.

Next, a test example of migration reproduction performed by using the migration reproduction test apparatus according to the present embodiment described above will be described.

<Test Example 1> Two PTC thermistors 26 (26B for demagnetization, 26A for heaters) of FIG. 10 were used to construct the posistor 10 as shown in FIG. It was set in a pressure resistant airtight container 1. Put a proper amount of water in the container body 2 and heat it by the heater 11 to set the temperature in the vicinity of the posistor 10 (internal temperature of the closed space) to 155 ° C. At this temperature, the posistor is rated via the current introducing terminal 9. The applied voltage was applied for 6 hours at the specified voltage.

After the test, the posistor 10 is taken out from the device 31, the case 41 is opened, the PTC thermistor 26 is taken out, and the side surface of the PTC thermistor 26 is taken by an optical microscope, a scanning electron microscope and an energy dispersive X-ray spectroscope. The presence or absence of migration of the electrode material Ag from the silver electrode of the PTC thermistor 26 was examined.

As a result, as shown in FIG.
The growth distribution of Ag migration 37 was confirmed in 26, and this portion was confirmed to be silver by qualitative analysis. Furthermore, the Ag migration 37 has grown from the electrodes 27A and 27B on both sides to the side surface of the main body 29 as shown in the figure,
It almost coincided with the generation mode in the general defective product shown in FIG. 9 (however, the nickel underlayer film is not shown).

<Test Example 2> The temperature near the posistor 10 was set to 191
The same test as in Test Example 1 was conducted except that the temperature was set to 0 ° C., and the presence or absence of Ag migration was examined in the same manner.

As a result, as shown in FIG.
Migration distribution to 26 confirmed the growth distribution of 37,
Qualitative analysis confirmed that this part was silver. Further, as in the case of Test Example 1, Ag migration 37 grew from the electrodes 27A, 27B on both sides to the side surface of the main body 29, which almost coincided with the general defective product generation mode shown in FIG.

<Test Example 3> The temperature in the vicinity of the posistor 10 was tested every 10 ° C within the range of the operating point temperature of the posistor 10 to 250 ° C. Also, the energizing application time at each of these temperatures is 10
Minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 10 hours. Further, the amount of water in the device 31 was changed, and the test was conducted every 10% in the humidity range of 60% from the saturated steam pressure. All other conditions were the same as in Test Example 1.

As a result, Ag migration of silver was confirmed after the test under all temperature, time and humidity conditions. Further, in this case, it was confirmed that the amount of Ag migration from both electrodes 27A and 27B to the side surface of the main body 29 increased depending on temperature, humidity and time.

<Test Example 4> Using the test apparatus 21 shown in FIG. 2, a plurality of posistors 10 are set in a pressure-resistant closed container 1 made of stainless steel, and an appropriate amount of water is put into the container body 2 to make the posistor 10 In the same manner as in Test Example 1 except that the temperature in the vicinity was set to 160 ° C., a plurality of posistors 10 were simultaneously subjected to a heating test for 6 hours to examine whether Ag migration occurred.

As a result, almost the same growth distribution of Ag migration was confirmed as in the case of Test Example 1 above.
This portion was confirmed to be silver by qualitative analysis, and the growth status of Ag migration was also in agreement with the general defective product generation mode in FIG.

<Test Example 5> In this example, the PT shown in FIG.
A test was conducted in the same procedure as in Test Example 1 except that the C element 30 was used. This PTC element 30 was developed for the purpose of suppressing Ag migration.
The nickel underlayer films 28A and 28B provided on both sides of a ceramic body 29 similar to the C element 26 are exposed in a ring shape at the peripheral edge of the main body, and a silver electrode 27A is provided inside the ring-shaped peripheral edge.
27B are formed respectively. Therefore, silver electrodes on both sides
The creepage distance between 27A and 27B is longer than that in FIG. 10, and the structure is such that Ag migration does not easily occur. Although the nickel base films 28A and 28B are formed by electroless plating and the silver electrodes 27A and 27B are formed by electroplating, the same applies to the element of FIG.

After the test, the presence or absence of Ag migration from the silver electrodes 27A and 27B was examined in the same manner as in Test Example 1 above. As a result, as compared with the results of Test Examples 1 to 4 above,
Ag migration occurred although it was very slight.
This was a very small amount that was difficult to discriminate with an optical microscope and could be observed with a scanning electron microscope and an energy dispersive X-ray spectrometer. This means that the element 30 of FIG. 11 has excellent migration resistance, but it is desired that Ag migration does not occur at all.

As described above, as is apparent from each of the above-mentioned test examples, in the conventional test method, even if dew condensation is caused on the PTC element, it is instantly dried, and it is impossible to artificially reproduce the migration. However, according to the method and apparatus of the present embodiment, it is possible to perform a test in which dew condensation is stably and surely generated, the dew condensation state is maintained, and migration can be easily reproduced in a short time.

According to this embodiment, in a posistor mounted in the vicinity of a picture tube of a television, Ag migration, which takes several years or more under normal use, can be artificially reproduced in a short time. The device and the device make it possible to immediately confirm the effectiveness and migration resistance of the migration prevention component. Therefore, the prospect for the development of a more complete PTC element is opened, and it can contribute to the improvement of the reliability of the product.

Although the embodiments of the present invention have been described above, the above-mentioned embodiments can be variously modified based on the technical idea of the present invention.

For example, the above-mentioned closed container, posistor, P
The structure, shape, material, etc. of the TC thermistor or the like can be any other desired one. Regarding the closed container, various closed structures can be adopted. PTC that constitutes a posistor
Of the thermistors, the one for the heater (27A described above) does not necessarily have to be used.

Also, various methods other than the above-mentioned embodiments can be adopted as the method of holding the posistor and the method of introducing the current. The heater for heating may be integrated with the closed container or may be embedded in the wall of the closed container. The method of supplying or generating water vapor is not limited to the heating method inside the container, but a method of supplying water vapor generated by heating water outside the container into the container is also possible.

Further, in addition to using the posistor containing the PTC thermistor for the test as described above, it is also possible to carry out the migration test by supporting the PTC thermistor itself in the closed container as described above.

Further, in the above-described embodiment, the PT in the posistor is used.
Although it relates to a migration reproduction test of the C element, the present invention is also applicable to a reproduction reproduction test of a migration that causes a short circuit between wirings of a semiconductor device, for example.

[0091]

As described above, according to the present invention, an object to be tested is supported in a container that can be sealed, and dew condensation is caused on the object to be tested, and the dew condensation causes migration to the object to be tested. Therefore, it is possible to generate stable and reliable dew condensation in a closed container to maintain this dew condensation state in a stable manner, and to perform an accelerated migration migration test with good reproducibility in a short time and with reliability. It is possible to surely contribute to the development of high quality products.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a closed container of a migration reproduction test apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the migration reproducing apparatus.

FIG. 3 is a sectional view showing a migration reproduction test apparatus according to another embodiment of the present invention.

FIG. 4 is a half cross-sectional perspective view of a current introducing terminal used in the migration reproduction test apparatus according to each example of the present invention.

5A is a sectional view showing a posistor used in the migration reproduction test, and FIG. 5B is a sectional view taken along line bb of FIG.

FIG. 6 is an exploded perspective view of the same posistor.

FIG. 7 is an enlarged side view of the PTC element after the Ag migration reproduction test according to the example.

FIG. 8 is an enlarged side view of the PTC element after another Ag migration reproduction test according to the example.

FIG. 9 is an enlarged side view of a general defective product of a PTC element due to Ag migration.

FIG. 10 is a perspective view of a PTC element according to a conventional example.

FIG. 11 is a perspective view of another PTC element.

FIG. 12 is a graph showing a temperature characteristic of resistance of a PTC element in comparison with a normal thermistor.

FIG. 13 is an equivalent circuit diagram of a degaussing circuit in which a posistor using a PTC element is connected.

[Fig. 14] Fig. 14 is a schematic diagram for explaining the color unevenness and the degaussing current of the screen of the television picture tube.

[Fig. 15] Fig. 15 is a schematic rear view of the picture tube showing the arrangement of degaussing coils provided in the picture tube.

[Explanation of symbols]

 1 ... Airtight container 2 ... Container body 3 ... Lid 4 ... Packing 7, 14 ... Thermocouple 7a, 7b, 14a, 14b ... Lead wire 8 ... Pressure gauge 8a. ..Conduit 9 ... Current introducing terminal 10 ... Positor 11 ... Heater 12 ... Heater wire 15a, 15b ... Screw 15c ... Pawl 16 ... Cap nut 16a ... Screw Part 17 ... Current conductor 18 ... Pressure contact tube 19 ... Insulating powder 20 ... Insulating material 21, 31 ... Migration reproduction tester 23, 24, 25 ... Terminal board 23a, 24b , 25b ... Elastic pieces 23b, 24c, 25c ... Connection portions 24a, 25a ... Elastic contact portions 26, 26A, 26B, 30 ... PTC elements 27A, 27B ... Silver electrodes 28A, 28B. ..Nickel base film 29 ... Insulating body 37 ... Ag migration 38 ... PTC thermistor characteristic curve 39 ... Thermistor characteristics Curve 40 ... water 42 ... television picture tube (CRT) 43 ... degaussing coil (degaussing coil) 44 ... Power 45a ... screen 46A, 46B ... color unevenness

Claims (13)

[Claims] 1. A migration reproduction test method in which an object to be tested is supported in an airtight container to cause condensation on the object to be tested, and the condensation causes migration to occur on the object to be tested. 2. The device under test is supported in a high temperature pressure vessel so that it can be energized, and the water in the high temperature pressure container is evaporated by heating to cause the water vapor to condense on the device under test. The method according to claim 1, wherein the high temperature pressure vessel is provided with a sealing means so as not to leak out of the pressure vessel. 3. The method according to claim 1, wherein the DUT is supported in a container and tested at a predetermined temperature and a predetermined vapor pressure for a predetermined time. 4. The method according to claim 3, wherein at least one of the amount of water and the heating energy with respect to the inner volume of the container is changed. 5. The method according to claim 3, wherein the inner temperature of the container is set to be equal to or higher than the operating temperature when the test object is actually used, the humidity in the container is set to 40% to saturated vapor pressure, and the test time is set to 1 minute or longer. The method described. 6. The method according to claim 1, wherein a posistor is used as the DUT. 7. The method according to claim 6, wherein a posistor used in a degaussing circuit of a cathode ray tube is tested. 8. A container which can be sealed, a support means for supporting an object to be tested in the container, and a means for imparting dew condensation to the object to be tested are provided, and migration to the object to be tested. A migration reproduction test device configured to generate 9. A hermetically sealed high-temperature pressure container containing a device under test, supporting means for supporting the device under test in an electrically conductive manner, heating means for heating the high-temperature pressure container, and The apparatus according to claim 8, further comprising: a steam generating unit that evaporates water and causes the steam to condense on the DUT; and a sealing unit that prevents the steam from leaking out of the high temperature pressure vessel. 10. The apparatus according to claim 9, further comprising temperature detecting means for detecting a temperature inside the container and pressure detecting means for detecting a pressure inside the container. 11. The means for supporting an object to be tested has a current introducing terminal body screwed and fixed to a container, and an insulating powder press-fit into the current introducing terminal body so as to support the current conducting wire in an airtight manner. The device of claim 9, wherein the device is configured to. 12. The apparatus according to claim 8, wherein a posistor as a device under test is supported in the container. 13. The reproduction test of migration between electrodes of a posistor used in a degaussing circuit of a cathode ray tube.
The device described in 1.