JP2003080153A - Active liquid coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an active liquid coating apparatus eliminating the waste of a noble metal because an electroless plating method capable of controlling film thickness is utilized and capable of coating the surface of an electronic component with a thin active film. SOLUTION: The active liquid coating apparatus 2 is constituted of a dispenser body 12 storing an active liquid 14, a coating part 21 for coating the surface of an electronic component 4 with the active liquid 14, the nozzle pipe 16 connected across the dispenser body 12 and the coating part 21, the penetration member 18 inserted in the nozzle pipe 16 to be connected to the coating part 21 at one end thereof and coming into contact with the active liquid 14 at the other end thereof to penetrate the active liquid 14 into the coating part 21, a means for bringing the coating part 21 into contact with the surface of the electronic component 4 and a means performing the relative motion of the coating part 21 and the electronic component 4 in a contact state to coat the desired region of the surface of the electronic component 4 with the active liquid 14. The active liquid is supplied to the surface of the electronic component by the coating part and natural force by utilizing the capillary phenomenon of the penetration member to form the active film and an electrode film is simply formed by electroless plating. Especially, an electrode is effectively formed to the inner surface of an oxygen sensor or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for applying an active liquid in a desired shape on the surface, particularly the inner surface, of an electronic component such as an oxygen sensor. More specifically, the active liquid is applied and then dried to lower the temperature. The active metal film consisting of an island-shaped film or a layered film is formed by firing at the temperature of, and then an electrode film is deposited and formed on the active metal film by electroless plating to complete an electronic component. The present invention relates to an active liquid coating device capable of reducing the waste of the amount of noble metal by coating with a thin film of an electrode film.

[0002]

2. Description of the Related Art With the development of electronic component technology, electrodes of electronic components such as semiconductors are often formed of precious metals such as platinum. Conventionally, this noble metal electrode has always been formed using a noble metal paste. The noble metal paste is a viscous semi-liquid substance formed by dispersing an organometallic complex of a noble metal together with a resin in an organic solvent.

If the noble metal paste is applied to a required portion of an electronic component to form a paste electrode film and the paste electrode film is dried and then the electrode portion is fired at a predetermined temperature, all organic substances are burned. Then, only the metal is finally sintered as a metal film to form a metal wiring or a metal electrode on the surface of the electronic component. Hereinafter, an oxygen sensor will be described as an example of the electronic component.

FIG. 15 is a cutaway sectional view of an essential part of an oxygen sensor used in an engine combustion system of an automobile. The oxygen sensor 32 has, as a main body, a ceramic body 34 made of a solid electrolyte formed in a cylindrical member (cup shape) with one end closed, and has a reference electrode 36 on its inner surface, which is in contact with a reference gas.
Is formed, and a measurement electrode 40 that contacts the gas to be measured is formed on the outer surface. In this specification, the reference electrode is referred to as an internal electrode and the measurement electrode is referred to as an external electrode in order to maintain common terms with general electronic components. In addition, the internal electrode 3
6 is provided with an internal lead portion 38 serving as a lead wire.

The oxygen sensor 32 is embedded in an exhaust pipe connected to the engine, the external electrode 40 contacts exhaust gas, and the internal electrode 36 contacts atmospheric air. An electric output proportional to the oxygen concentration difference between the exhaust gas and the atmosphere is generated between the electrodes 36 and 40, and information on excess oxygen or insufficient oxygen is fed back to the control system. Based on this information, the amount of air mixed with the fuel gas is automatically adjusted to the optimum value.

FIG. 20 is an explanatory view of forming internal electrodes inside the oxygen sensor. A discharge member 44 is formed in the application portion of the hollow paste nozzle tube 42 having a closed tip, and a plurality of discharge holes 46 penetrating the paste nozzle tube 42 and the discharge member 44 are formed.

The tip of the paste nozzle tube 42 is inserted into the inner hollow portion of the ceramic body 34, and the distance h between the inner surface of the ceramic body 34 and the surface of the discharge member 44 is set to a predetermined value, and then the noble metal paste is moved backward. Then, the ceramic body 34 is rotated once in the direction of arrow a while being pressure-fed at an appropriate pressure. As a result, the noble metal paste is discharged from the discharge holes 46, and the paste annular body 50 having the thickness h is formed on the inner surface.

After forming the paste annular body 50, when the paste nozzle tube 42 is retracted in the direction of arrow b, the thickness h is obtained.
The paste lead body 52 is formed. That is, the undried paste annular body 50 is formed on the inner surface of the ceramic body 34.
Then, the paste lead body 52 is completed.

When the ceramic body 34 is dried and then fired at about 1000 ° C., all the organic substances in the paste are burned and removed, and finally only the metal components such as platinum remain, as shown in FIG. Internal electrode 36 and lead 3
8 is formed.

[0010]

The performance of the oxygen sensor depends on the density and thickness of the electrode. When the electrode is formed from the paste, the thickness is reduced by drying and firing, so that the paste film thickness must be determined in consideration of the reduction rate of the paste film thickness in order to obtain a predetermined electrode film thickness.

However, since the organic solvent contained in the paste evaporates during standing, the components of the paste change with time, and even if the paste film thickness is made constant, it depends on the manufacturing conditions. In general, an error occurs in the electrode film thickness.

The thickness of the paste is determined by the ceramic body 34.
Although it depends on the distance h between the inner surface of the discharge member 44 and the discharge member 44, the setting of the distance h is mechanically performed by a measuring instrument such as a micrometer, and thus the adjustment is considerably troublesome. In particular, different shapes of the ceramic body 34 must be readjusted. Also, since the paste supply amount also depends on the pumping pressure,
That adjustment is also difficult.

Further, although the paste contains a considerable amount of noble metal, when the paste is solidified in the paste nozzle tube 42 or the dispenser main body for storing the paste, the noble metal contained therein is wasted. There is. In particular,
When the paste solidifies in the paste nozzle tube 42,
Not only is the paste wasted, but it becomes impossible to inject the paste, and expensive nozzles must be replaced.

Therefore, the present inventors have decided to adopt an electrode forming method for electronic parts, which is a combination of an active liquid and an electroless plating method, instead of the paste coating method which is wasteful and difficult. did. Since the active liquid is a free-flowing liquid, clogging and solidification hardly occur. Therefore, waste of noble metal is eliminated, and at the same time, adjustment of the electrode film thickness is facilitated.

That is, the active liquid coating apparatus according to the present invention is
By providing a specific device that can form an extremely thin active film on the surface of electronic parts such as oxygen sensors, it is possible to eliminate the waste of precious metal and to control the metal film thickness on this active film with high precision. The purpose is to be able to apply the electroless plating method.

[0016]

The present invention has been made to achieve the above object, and a first invention thereof is a dispenser main body which stores an active liquid and an active liquid applied to the surface of an electronic component. The coating section, the nozzle tube connected between the dispenser body and the coating section, and the nozzle tube inserted into the nozzle tube, one end of which is connected to the coating section and the other end of which is in contact with the active liquid, so that the active liquid is applied to the coating section. It is composed of a permeation member for permeation, and the active liquid is moved to the application part through the permeation member to wet the application part with the active liquid. The active liquid can be freely applied to a desired region on the surface of the electronic component by moving the application unit and the electronic component relative to each other while the application unit is in contact with the surface of the electronic component. The permeation member and the application part may be integrally formed from the permeation member or may be separately formed. The length of the permeating member can be adjusted freely, and the end of the permeating member, which is the end of the classifying liquid, may have a length that protrudes from the nozzle tube into the dispenser body, or the flow rate up to the middle of the nozzle tube. However, it is sufficient as long as it has at least the ability to supply the active liquid to the coating section.

A second aspect of the present invention provides an active liquid coating device in which the length of the insertion portion of the penetrating member inserted in the nozzle tube is 5 times or more the diameter of the nozzle tube. The active liquid can be efficiently supplied to the application part to increase the wettability of the application part, and the application state on the surface of the electronic component can be made effective.

In a third aspect of the invention, the dispenser body is arranged substantially vertically, and the permeating member has a capillary phenomenon with respect to the active liquid, and the active liquid naturally permeates into the permeating member due to this capillary phenomenon. A stable coating film can be formed on the surface of the electronic component by the coating section without control. When arranged substantially vertically, the flow-down force due to the self-weight of the active liquid is added to the capillary liquid absorption force, and the natural permeability of the active liquid can be enhanced. The active liquid in the dispenser body may be pumped to enhance the penetrating power.

A fourth invention is to arrange a cylindrical electronic component,
The application part of the permeation member is inserted into the hollow part of the tubular electronic component, and the active liquid is applied by bringing the application part into contact with the inner surface of the electronic component. By combining the rotation control and the insertion control of the electronic component. It can contribute to the automation of coating work.

A fifth aspect of the present invention is a cup-type oxygen sensor made of a solid electrolyte in which an electronic component has a reference gas chamber provided therein, and the coating portion is inserted into the reference gas chamber of the oxygen sensor to form a coating portion. Is applied to the inner surface of the oxygen sensor to apply the active liquid to the area where the reference electrode is to be formed.
The active liquid can be efficiently applied to the inner surface of the cup-shaped oxygen sensor.

According to a sixth aspect of the present invention, the permeation member is made of felt, a fibrous body or a porous body, and these permeation members have a strong capillary action for the active liquid and supply the active liquid to the application part smoothly and naturally. be able to.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have earnestly studied an alternative method of forming an electrode film by a paste coating method, and as a result, it is most desirable to form an electrode by using an active film and an electroless plating method together. I reached the conclusion. The present invention has been completed as an apparatus for forming an active film.

The active film is a film formed by coating an active liquid (active catalyst liquid) on the surface on which an electrode is to be formed. The active catalyst means an active metal such as platinum. For example, an active solution is prepared by dispersing an organic complex of this active metal in an organic solvent.

The active liquid is applied to a desired surface of an electronic component to form an active film, and the active film is dried.
For example, when the active film is baked at 600 ° C., all the organic components in the active film are burned and removed, and finally the active metal film is formed. The active metal film has a structure in which active metal nuclei are dispersed in an island shape, and it is preferable that the active metal nuclei are formed in a state of being as fine and uniform as possible.

Next, the electronic component having the active metal film formed thereon is immersed in an electroless plating solution. Metal is deposited on the active metal nuclei and each island grows into a continuous thin film,
Further, metal is deposited and the film thickness increases. Thus, the metal is continuously deposited only on the surface of the active metal film. The thickness of the metal film depends on the metal concentration of the electroless plating solution, the plating time and the temperature of the plating bath. Since this metal film constitutes the electrode film, the thickness control of the electrode film is performed in the electroless plating step. Therefore, the thickness of the electrode film can be controlled simply and accurately.

Therefore, the plating formation region of the electrode film is limited to the range of the active film, and the excellent formation of the active film and the denseness of the active metal film influence the success or failure of electroless plating in the subsequent process. That is, since this active film is a precursor film of the electrode film to be formed, the degree of excellence of the precursor film affects the excellence of the electrode film. The present invention relates to an active liquid coating device that forms the active film on an electronic component. Hereinafter, an embodiment of an active liquid coating device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view of an active liquid coating apparatus according to the present invention. The present inventors have already published the main structure of the active liquid coating device 2 as WO99 / 62644 internationally. In this publication, this device is disclosed as a paste uniform coating device for injecting a metal paste, but in the present invention, this device is improved to be an active liquid coating device.

The active liquid coating device 2 is a horizontal type device in which an electronic component side device 2a and an active liquid side device 2b are horizontally connected. Of course, a vertical device in which these devices 2a and 2b are arranged vertically may be used. The electronic component side device 2a includes a mounting portion 6 for fixing the tubular electronic component 4, a rotation driving portion 8 configured to rotatably mount the mounting portion 6, and a vertical position for vertically moving the rotation driving portion 8 integrally. It is composed of the adjusting device 10.

The active liquid side device 2b includes a dispenser body 12 in which the active liquid 14 is stored, a pressure-feeding portion 22 for pressure-feeding the active liquid 14, and a nozzle pipe 16 for pouring out the active liquid 14.
And an application part 21 which is a pen tip for applying the active liquid 14, and an advancing / retreating movement device 24 for moving the application part 21 left and right.

FIG. 2 is a simplified explanatory view of the coating operation on the inner surface of the electronic component by the coating section. The electronic component 4 is rotated in the arrow A direction, the height of the nozzle tube 16 and the coating portion 21 is adjusted in the arrow C direction, and the electronic component 4 is advanced and retracted in the hollow portion of the electronic component 4 in the arrow B direction. It goes without saying that the height of the electronic component 4 can be adjusted in the direction of arrow C and, at the same time, it can be moved back and forth in the direction of arrow B. Therefore, the application is performed by rotating, advancing and retracting, and adjusting the height.

FIG. 3 is a cross-sectional view of a pouring portion for the active liquid, which is the main part of the present invention. Active liquid 1 in dispenser body 12
4 are stored. An L-shaped nozzle tube 16 is disposed at the lower end of the dispenser body 12, and a penetrating member 18 is inserted inside the nozzle tube 16.

The permeation member 18 is made of a material that permeates the active liquid 14 into the coating portion 21 by a capillary phenomenon. Therefore, the permeation member 18 is provided with a liquid absorbing end 19 that is projected into the active liquid 14 and absorbs the active liquid 14, an intermediate portion 20 that transmits the active liquid 14 by capillary action, and the active liquid 14
It is composed of a coating section 21 which serves as a pen tip for coating.

In this embodiment, the liquid absorption end 19 of the penetrating member 20 projects into the dispenser body 12, but it may be located at any position in the middle of the nozzle tube 16. That is,
The permeation portion length L may be longer than the length Ln of the nozzle tube 16 (L> Ln), but may be 0 <L ≦ Ln. L ≦
In the case of Ln, the active liquid is located inside the nozzle tube 16, but the active liquid 14 is sufficiently sucked by the liquid suction end 19 of the permeation member 20 and supplied to the coating unit 21. Nozzle tube 1
Assuming that the inner diameter (inner diameter) of 6 is R, as will be described later,
It can be seen that the osmotic force of the active liquid depends on the L / R ratio.

The material of the permeation member 18 is selected from the materials exhibiting the capillary phenomenon. In particular, the material used for the pen tip of the marking pen is suitable. For example, felt pen material made of wool, synthetic fiber, heat-sealed fiber, etc. in a soft felt shape, felt felt material made by applying resin treatment to this felt, synthetic fiber such as acrylic, polyester, nylon, etc. There are synthetic fiber pen materials that are reinforced by bonding with a resin, and fiber pen materials that use other fibers.

The material that causes the capillary phenomenon is not limited to a fibrous pen material such as a felt pen or a fiber pen, and a plastic pen material having a communication hole inside which the active liquid is transmitted by the capillary phenomenon can be used. For example, a copolymer such as a polyacetal resin or a homopolymer has innumerable gaps (communication holes) therein, and the gaps cause a capillary phenomenon. Therefore, this plastic pen material is also a material of the penetrating member 18. Further, a porous material having a communicating hole such as a sponge body also serves as the penetrating material.

The coating portion 21 of the penetrating member 18 is a pen tip, and is formed in a shape that allows the active liquid 14 to be easily coated on the electronic component 4. The coating part 21 includes a curved part 21a and a straight part 2
1b, the curved portion 21a can be applied to the curved portion, and the straight portion 21b can be applied to the inner peripheral surface.

In order to insert the penetrating member 18 into the nozzle tube 16 in an L-shape, the linear penetrating member 18 is first inserted into the straight tubular nozzle tube, and then the nozzle tube is bent into an L-shape. Formed by processing.

The active liquid 21 is a free-flowing liquid composed of a metal compound containing an active metal. Platinum or the like is often used as the active metal, balsam platinum sulfide or the like as the metal organic compound, and platinum chloride or the like as the metal inorganic compound. The metal organic compound or metal inorganic compound is dispersed in an organic solvent to obtain an active liquid.

The inventor of the present invention has also proposed in JP-A-9-272996 an active liquid in which a noble metal organic complex is dispersed in an organic solvent. Particularly, as the noble metal organic complex, an active liquid in which a bis [di (substituted) benzylideneacetone] noble metal or tris [di (substituted) benzylideneacetone] noble metal is dispersed in an organic solvent is effective.

As described above, unlike the paste, the active liquid is a free-flowing liquid having a low viscosity, and thus is a material which is hard to solidify in the dispenser body 12 and hard to solidify in the permeating member 18. Therefore, in the conventional coating device using the paste, the paste may be hardened in the nozzle tube and it may be difficult to pour the paste. However, the active liquid coating device using the permeation member 18 of the present invention may be used. In case 2, such a situation is unlikely to occur, and an appropriate amount of the active liquid 14 is always applied to the coating portion 21.
Can be poured from.

In the case of paste, if it solidifies in the dispenser body 12 or adheres to other members, those pastes are wasted, and the noble metal contained in the paste is also wasted. Met. However, since the active liquid does not attach a considerable amount to unnecessary portions, there is an advantage that the waste of precious metals can be reduced.

The active liquid 14 is applied to the application part 2 by the capillary phenomenon.
1 is always wet. However, there is a limit to the supply amount of the active liquid 14 only by the water absorption capacity of the capillary tube. Therefore, when the active liquid 14 is applied to the electronic component 4, the active liquid 1
When it is desired to increase the amount of 4, the active liquid 14 can be forcedly permeated and supplied by the pressure of the pressure feeding portion 22.

FIG. 4 is a process drawing of applying the active liquid to the inner surface of the electronic component. In FIG. 1, the straight line portion 21 b of the coating portion 21 is moved to the inner peripheral surface 4 of the electronic component 4 by the vertical position adjusting device 10.
Adjust the height so that it contacts a. Next, the coating unit 21 is moved forward to a predetermined position inside the electronic component 4 by the advancing / retreating movement device 24.

When the linear portion 21b is in contact with the inner peripheral surface 4a of the electronic component 4, the active liquid moistening the coating portion 21 is transferred to the inner peripheral surface 4a, and the active liquid is deposited on the inner peripheral surface 4a. It adheres extremely thinly. When the electronic component 4 is rotated once in this positional relationship, the internal active film 25 is formed on the inner peripheral surface 4a over 360 degrees.

FIG. 5 is a sectional view taken along line AA of FIG. When the width of the coating portion 21 is W and the width of the active liquid coated on the inner surface by the coating portion 21 is w, generally W ≦ w is satisfied. Since the coating width w becomes larger than the coating portion width W as the osmotic force of the active liquid is larger, the coating efficiency can be estimated from the magnitude relationship between w and W. In the test described later, w-W is 2 m
A value of m or less was judged as good (◯), and a value of more than 2 mm was judged as poor (x).

FIG. 6 is a partially enlarged view of FIG. Application part 2
1 and the electronic component 4 are preferably in contact with each other, and the coating surface 21d of the coating portion 21 preferably has a curvature that is substantially the same as the curvature of the inner surface of the electronic component 4. However, since the gap between the coating surface 21d and the inner side surface is very small, it is not necessary to actively design the curved surface, and even if it is formed in a substantially linear shape, the coating characteristics are not significantly affected.

FIG. 7 is a process drawing of forming a lead active film on the inner surface of an electronic component. When the coating portion 21 is retracted in the direction of the arrow b from the state of FIG. 4, the lead active film 26 is continuously formed with a width w corresponding to the thickness W of the coating portion 21. At this stage, the inner active film 25 and the lead active film 26 continuous with the inner active film 25 are formed as active films by coating on the inner surface of the electronic component 4.
When electroless plating is applied to this active film, internal electrodes 36 shown in FIG. 15 are formed.

FIG. 8 is a process diagram of applying the active liquid to the inner depth of the electronic component. In the case of being used as an oxygen sensor, the internal electrode formed in the inner part of the electronic component provides the most efficient sensor. Therefore, the shape of the curved portion 21a of the coating portion 21 is made to match the shape of the inner back surface 4b of the electronic component 4.

While the linear portion 21b is in contact with the inner peripheral surface 4a of the electronic component 4, the coating portion 21 is moved forward to move the curved portion 21a.
To the inner surface 4b of the component. Electronic component 4 in this state
Is rotated once in the direction of arrow a, the active liquid adheres and the inner active film 25 and the tip active film 25a are integrally formed. After that, the coating section 21 is retracted to form a lead active film (not shown).

FIG. 9 is a partially cutaway sectional view of an electronic component on which an active film is formed. The tip active film 25 is formed on the inner surface of the electronic component 4.
The internal active film 25 and the lead active film 26 are formed. The electronic component 4 is dried and baked at 400 to 600 ° C. to remove organic substances from the active film to form an active metal film. When this is electroless plated, a metal such as platinum is plated on the active metal film to form internal electrodes.

FIG. 10 is a process diagram for forming an active film on an electronic component having a step. The coating section 21 is the straight section 21.
b has a vertical end 21 instead of the curved portion 21a.
forming c. In this state, the electronic component 4 is rotated once to form the inner active film 25 at 360 ° C. After that, the coating section 21 is retracted in the direction of arrow b.

FIG. 11 is a completed view of the process of FIG. When the coating portion 21 is moved back and reaches the step portion 4c, the vertical end 21c is moved along the step portion 4c to form the step active film 26a. Therefore, in the case of the electronic component 4 having the step portion 4c, the internal active film 25 and the lead active film 26 are provided.
The step active film 26a constitutes an active film.

When the active film is formed on the inner surface and the outer surface of the electronic component 4, the electronic component 4 is dried and the organic solvent is evaporated from the active film. Next, the electronic component 4 is fired at about 600 ° C. to burn and remove organic substances, and the active film is converted into a dense active metal film.

As described above, the active metal film is a precursor metal film made of only active metal, and its thickness may be about 1 μm, for example. Finally, the electronic component is immersed in an electroless plating solution to electrolessly deposit the active metal on the active metal film to form an electrode film. At this time, the thickness of the electrode film can be freely controlled by adjusting the concentration of the electroless plating solution, the plating temperature, and the plating time.

FIG. 12 is a sectional view showing a modified example of the coating section. The tip of the coating part 21 is formed in a hemispherical shape, and the spherical surface is formed slightly smaller than the shape of the inner surface 4b of the electronic component 4 inside the component. Since it has a hemispherical shape, even if the coating section 21 collides with a member during operation, it is difficult to deform and has durability.
When the semi-spherical surface is brought into contact with the inner back surface 4b and the electronic component 4 is rotated, the tip active film 25a and the inner active film 25 are blown at once.
Is formed.

FIG. 13 is a sectional view showing a modified example of the permeation member. The penetrating member 18 has a middle portion 20 having a length L.
The penetrating member 18 integrally forms the coating portion 21 and the liquid absorbing portion 19. The liquid absorbing portion 19 has a length L so that the coating portion 21 does not fall off, and the nozzle tube locking portion 16a is provided to prevent the coating portion 21 from falling off.
Is provided to fix the tip of the coating unit 21. Therefore,
The active liquid 14 has entered the vicinity of the tip of the nozzle tube 16. Even in such a case, the active liquid 14 permeates from the liquid suction end 19 and the coating portion 21 is in a wet state with the active liquid.

FIG. 14 is a cross-sectional view of an active liquid pouring portion using another modified example of the permeation member. Liquid absorbing end 1 of permeation member 18
Reference numeral 9 is at an intermediate position of the nozzle pipe 16, and the active liquid 14 has entered the nozzle pipe 16. Therefore, the liquid absorbing portion 19 absorbs the active liquid 14 in the nozzle tube 16.

The penetrating member length L of the penetrating member 18 and the inner diameter R (inner diameter) of the nozzle tube 16 were changed, and the material of the penetrating member 18 was changed to measure the coating characteristics. As described above, the applicability is determined by determining that the extension amount (bleeding amount) is 2 mm or less from the application member width W of the application width w (good), 2 m.
Those exceeding m were regarded as defective (x). The results are listed in Table 1.

[0059]

[Table 1]

As can be seen from Table 1, the coating characteristics change with L / R as a parameter. By setting the L / R value to 5 or more, preferably 10 or more, an excellent coating film can be obtained.
Since the active liquid is a free-flowing liquid and easily permeates the permeation member 18, if L / R is less than 5, it becomes difficult to control the amount of the active liquid supplied from the coating section 21, and a large bleeding may occur in the coating film. I understand.

Even in the region of L / R <5, there is a method of increasing the viscosity of the active liquid and feeding it under pressure. However, when the permeation member length L is short, pressure control for forming a fine coating film is performed. Is difficult, and costs more than necessary for the control device,
The advantage of the present invention becomes insufficient.

When the value of L / R is large, No. 1 in Table 1 is used. In the case of 18, the coating amount is insufficient, and there is a possibility that scraping or the like may occur. Therefore, pressure feeding gives a superior coating film. N
o. Reference numerals 29 and 30 are examples in which porous rubber was used for the coating member, but a material having slightly less pores than the felt was selected, and therefore pressure feeding gave a desirable result.

As described above, FIG. 15 is a cutaway sectional view of a main part of an oxygen sensor used in an engine combustion system of a vehicle. The oxygen sensor 32 described as an example of an electronic component includes a ceramic body 34 made of a solid electrolyte, an internal electrode 36 corresponding to a reference electrode, an internal lead body 38 for connecting the internal electrode 36 to an external circuit, and a measurement electrode. It is composed of a corresponding external electrode 40.

First, in order to form the external electrodes 40, an active paste containing a noble metal compound for forming noble metal nuclei is applied and printed on the outer surface of the ceramic body 34 in a desired external electrode shape by a roll pad transfer method. This coating film is heated to dry the organic solvent and the like in the active paste.

Then, in order to form the internal electrode 36,
With the device of the present invention shown in FIGS. 1 and 3, an active liquid containing a noble metal compound for forming noble metal nuclei is applied to the inner surface in the shape of a desired internal electrode and heated to dry an organic solvent or the like. Further, the binder and the like in the coating film are removed by heating at 400 ° C. to 600 ° C., the precious metal compound is decomposed, and a precious metal nucleus is formed in the coating film portion. By this firing, the organic components are removed and the external electrode 40 is also completed.

Next, electroless plating is applied to the noble metal nucleus forming portion of the internal electrode portion to form a plated film electrode, and the internal electrode 36 is formed.
Was completed. Platinum is most preferable for the noble metal nucleus and the plating film, but Pd, Au, Rh, etc. may be used, for example. Of course, the noble metal nucleus and the plating film do not have to be made of the same material.

FIG. 16 is an external view of external electrodes of another oxygen sensor. The external electrode 40 is a measurement electrode that comes into contact with the exhaust gas, is connected to the external electrode terminal portion 41 via the external lead body 39, and supplies a signal to an external circuit. In the following example, the oxygen sensor 32 has the same appearance as that of FIG.

FIG. 17 is a sectional view for explaining the pattern of the internal electrodes of FIG. In the vertical sectional view of (A), the internal electrode 36 and the internal electrode terminal portion 37 are connected by an internal lead body 38. (B) is a vertical cross-sectional view of a position where the inner lead body 38 cannot be seen, and (C) is a horizontal cross-sectional view in which two inner lead bodies 38, 38 and one outer lead body 39 are formed. I understand.

FIG. 18 is a sectional view for explaining another pattern of the internal electrodes of FIG. (A) shows a state in which the internal electrode 36 and the internal electrode terminal portion 37 are connected by an internal lead body 38, and (B) shows two internal lead bodies 38, 3
8 and two external lead bodies 39, 39 are formed.

FIG. 19 is a sectional view for explaining another pattern of the internal electrodes of FIG. Although the state where the internal electrode 36 and the internal lead body 38 are connected is shown in (A), the internal electrode terminal portion 37 is not formed. Internal lead body 3
The upper end portion of 8 also serves as the internal electrode terminal portion 37.
Although the state where two inner lead bodies 38, 38 and two outer lead bodies 39, 39 are formed is shown in (B), the inner lead bodies 38, 38 and the outer lead bodies 39, 3 are shown.
It can be seen that 9 are rotated by 90 degrees with respect to each other.

As described above, the present invention relates to an apparatus that can apply an active liquid in a free shape to the inner surface of a general electronic component, and has described an oxygen sensor as an example of the electronic component. Even if only the oxygen sensor is taken up, there are various electrode shapes and various cup shapes, and naturally many shapes exist for electronic parts. However, it goes without saying that the present invention exhibits good properties for applying the active liquid to the inner surface of the cylindrical electronic component, and the active liquid can be applied to the outer surface more easily.

The active liquid coating device 2 can also be constructed as a vertical device in which the electronic component side device 2a is arranged below and the active liquid side device 2b is arranged above. The following device is considered as an example of this case. The electronic component 4 is erected vertically and its opening is arranged above. The nozzle tube 16 is a vertical tube that hangs vertically downward from the dispenser main body 12, and the coating portion 21 faces downward. The coating portion 21 is moved downward to bring the coating portion 21 into contact with the inner surface of the electronic component 4, and the inner active film 25 and the lead active film 26 are formed by rotation and vertical movement.

The vertical device may be tilted to form a tilting device. In this inclined arrangement, it is considered that when the active liquid side device 2b is placed above, the active liquid is more likely to wet the application portion 21 due to the capillary phenomenon. However, these geometrical arrangements can be arbitrarily arranged depending on the case in order to form an optimum device.

In addition, the present invention is not limited to the above-described embodiment, and various modifications, design changes and the like within the technical scope of the present invention are included in the technical scope thereof. There is no end.

[0075]

According to the first aspect of the present invention, the active liquid can be strongly supplied from the dispenser body to the coating portion by the permeating member in the nozzle tube, so that the coating portion is always wet with the active liquid. If the coating section and the electronic component are moved relative to each other while the coating section is in contact with the surface of the electronic component, the active liquid can be freely coated on a desired region of the surface of the electronic component. In particular, by arbitrarily changing the shape of the nozzle tube or the shape of the coating portion, it is possible to freely coat the inner surface of the electronic component. Further, the permeation member and the coating portion may be integrally formed from the same permeation material, or may be separately formed from the same material or different materials, and various configurations can be adopted. Further, the length of the permeating member can be freely adjusted, and the end of the classifying liquid, which is the rear end of the permeating member, may have such a length that it projects from the nozzle tube into the dispenser body, or even if it flows halfway through the nozzle tube. Well, it is an object of the present invention to provide an apparatus effective for applying the active liquid to the surface of the electronic component, such as having at least the ability to supply the active liquid to the application part.

According to the second invention, in the penetrating member inserted in the nozzle tube, if the length of the inserting section is set to be 5 times or more the diameter of the nozzle tube, the active liquid can be efficiently supplied to the applying section. Thus, the wettability of the application part can be increased, and the active liquid applied to the surface of the electronic component can be effectively prevented from oozing out from the contact surface of the application part to an unnecessary area on the surface of the electronic component.

According to the third aspect of the invention, since the dispenser body is arranged substantially vertically, the downward force due to the self-weight of the active liquid is added to the capillary liquid absorption force of the permeation member, and as a result, the natural permeation of the active liquid is enhanced. Therefore, the active liquid can be naturally and surely applied to the surface of the electronic component without using a driving force. Of course, in order to enhance the penetrating force, a method of pumping the active liquid of the dispenser body may be used together.

According to the fourth aspect of the present invention, the cylindrical electronic component is arranged, the coating portion of the permeation member is inserted into the hollow portion of the cylindrical electronic component, and the coating portion and the inner surface of the electronic component are brought into contact with each other. Since the active liquid is applied, automation of the application work can be achieved by the basic mechanism of rotation control and insertion control, and the active liquid can be applied freely to electronic parts having various and complicated structures.

According to the fifth aspect of the invention, since the cup type oxygen sensor made of a solid electrolyte having a reference gas chamber provided therein is used as an electronic component, the active liquid is provided on the inner surface of the oxygen sensor having various structures. Can be applied in a desired shape, and combined with subsequent electroless plating enables continuous production of an oxygen sensor having a good electrode pattern, and achieves cost reduction and mass production of the oxygen sensor.

According to the sixth aspect of the invention, since the permeation member is made of felt, fibrous body or porous body, these permeation members have a strong capillary action on the active liquid, and a driving force such as pumping is used. Even if it does not exist, there is an advantage that the active liquid can be smoothly supplied to the application portion by natural force.

[Brief description of drawings]

FIG. 1 is a front view of an active liquid coating apparatus according to the present invention.

FIG. 2 is a simplified explanatory diagram of a coating operation on an inner surface of an electronic component by a coating unit.

FIG. 3 is a cross-sectional view of a portion for pouring an active liquid, which is a main part of the present invention.

FIG. 4 is a process diagram of applying an active liquid to the inner surface of an electronic component.

5 is a cross-sectional view taken along the line AA of FIG.

6 is a partially enlarged view of FIG.

FIG. 7 is a process drawing of forming a lead active film on the inner surface of an electronic component.

FIG. 8 is a process diagram of applying an active liquid to the inner depth of the electronic component.

FIG. 9 is a partially cutaway sectional view of an electronic component on which an active film is formed.

FIG. 10 is a process drawing for forming an active film on an electronic component having a step portion.

11 is a completed view of the process of FIG.

FIG. 12 is a cross-sectional view showing a modified example of the coating unit.

FIG. 13 is a cross-sectional view showing a modified example of the permeation member.

FIG. 14 is a cross-sectional view of a spout of the active liquid using another modified example of the permeation member.

FIG. 15 is a cutaway sectional view of an essential part of an oxygen sensor used in an engine combustion system of an automobile.

FIG. 16 is an external view of external electrodes of another oxygen sensor.

FIG. 17 is a cross-sectional view illustrating a pattern of the internal electrode of FIG.

18 is a cross-sectional view illustrating another pattern of the internal electrode of FIG.

19 is a cross-sectional view illustrating another pattern of the internal electrode of FIG.

FIG. 20 is an explanatory diagram of forming internal electrodes inside the oxygen sensor.

[Explanation of symbols]

2 is an active liquid coating device, 2a is an electronic component side device, 2b is an active liquid side device, 4 is an electronic component, 4a is an inner peripheral surface, 4b is an inner part of the component, 4c is a step portion, 6 is a mounting portion, 8 Is a rotation drive unit, 1
0 is a vertical position adjusting device, 12 is a dispenser body, 14
Is an active liquid, 16 is a nozzle tube, 18 is a permeating member, 19 is a liquid absorbing end, 20 is an intermediate part, 21 is a coating part, 21a is a curved part,
21b is a straight part, 21c is a vertical end, 21d is a coated surface, 2
2 is a pumping unit, 24 is a forward / backward moving device, 25 is an internal active film,
25a is a tip active film, 26 is a lead active film, 26a is an active film step, 32 is an oxygen sensor, 34 is a ceramic body,
36 is an internal electrode, 37 is an internal electrode terminal portion, 38 is an internal lead body, 39 is an external lead body, 40 is an external electrode, 41 is an external electrode terminal portion, 42 is a paste nozzle tube, 44 is a discharge member, and 46 is Discharge hole, 48 is paste, 50 is paste annular body, 52 is paste lead body, h is paste thickness,
L is the permeation member length, R is the inner diameter of the nozzle tube, W is the coating width, and w is the coating width.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomoaki Tsujimoto             2-7-19 Nishi, Saito-ku, Osaka-shi, Osaka               Within Daiken Chemical Industry Co., Ltd. (72) Inventor Akio Harada             2-7-19 Nishi, Saito-ku, Osaka-shi, Osaka               Within Daiken Chemical Industry Co., Ltd. (72) Inventor Kiyomi Kobayashi             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO (72) Inventor Motoaki Sato             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO (72) Inventor Nami Fujii             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO F-term (reference) 4F042 AA01 AA06 BA02 BA03 CA01                       CB11 CB19 EA10 EA18 EA24                       EA35                 4K022 AA04 AA11 AA13 AA36 AA37                       AA41 BA03 BA18 BA35 CA06                       CA20 CA21 CA22 CA29 DA01                       DB15 DB19

Claims (6)

[Claims] 1. A dispenser body storing an active liquid,
An application part for applying the active liquid to the surface of the electronic component, a nozzle tube connected between the dispenser body and the application part, and one end connected to the application part and the other end inserted into the nozzle tube A penetrating member that comes into contact with the permeation member to permeate the active liquid into the coating portion, and a means for bringing the coating portion into contact with the surface of the electronic component,
An active liquid coating device comprising means for relatively moving the coating part and the electronic component in a contact state to coat the desired region on the surface of the electronic component with the active liquid. 2. The active liquid coating apparatus according to claim 1, wherein the penetrating member inserted in the nozzle tube has an insertion portion length of 5 times or more the diameter of the nozzle tube. 3. The dispenser body is arranged substantially vertically, and the permeation member has a capillary phenomenon with respect to the active liquid, and the active liquid naturally permeates the permeation member due to this capillary phenomenon,
The active liquid coating apparatus according to claim 1, wherein a stable coating film can be formed on the surface of the electronic component by the coating section without special control. 4. A cylindrical electronic component is arranged, the application part of the permeation member is inserted into the hollow part of the cylindrical electronic component, and the active part is applied by bringing the application part into contact with the inner surface of the electronic component. Item 5. The active liquid coating device according to item 1, 2 or 3. 5. The electronic component is a cup-type oxygen sensor made of a solid electrolyte in which a reference gas chamber is provided. The coating part is inserted into the reference gas chamber of the oxygen sensor, and the coating part is oxygen sensor. The active liquid application device according to claim 4, wherein the active liquid is applied to a region where the reference electrode is to be formed by contacting the inner surface of the active liquid. 6. The active liquid coating device according to claim 1, wherein the permeation member is made of felt, a fibrous body or a porous body.