JP7608741B2 - Electronic component and method for manufacturing electronic component - Google Patents

Description

The present invention relates to an electronic component covered with an exterior case on which a display is formed, and a method for manufacturing the electronic component.

Commonly used electronic components include condensers, batteries, coils, and transformers. These electronic components are equipped with an exterior case that houses an element. The element is a component that performs the main function required of an electronic component. For example, if the element is a capacitor, it contains at least an anode foil, a cathode foil, and an electrolyte, and stores and discharges electric charge through capacitance. The exterior case protects the element from the external environment, and also protects the external environment from liquids in the element and gases generated by the element.

Metal exterior cases are sometimes chosen. However, in recent years, circuits have become more densely packed with various components, and there is a risk that a metal exterior case will come into contact with the circuit board on which the electronic components are mounted or with other components, causing a short circuit. In addition, metal exterior cases are prone to corrosion and discoloration, which can worsen the appearance of the electronic components. For this reason, the outer surface of the exterior case is usually covered with an insulating coating layer.

On such exterior cases, a marking is formed showing product information of the electronic component to inform the user of the product information of the electronic component. The marking is made up of letters, numbers, figures, patterns and other symbols, and if the electronic component is a capacitor, it shows the polarity, rated voltage, capacitance, trademark, serial number, etc.

One method of forming the markings is to remove only the opaque insulating coating layer with laser light according to the shape of the symbol (see, for example, Patent Document 1). With this method, the markings become visible due to the difference between the background color of the exterior case and the color of the insulating coating layer. Another method of forming the markings is to carve the outer surface of the exterior case together with the insulating coating layer with laser light according to the shape of the symbol (see, for example, Patent Document 2). With this method, the markings become visible due to the difference in the amount of light reflected from the outer surface of the exterior case and the carved portion.

Japanese Patent Application Publication No. 55-110001 JP 2002-346633 A

Whether the method of forming the marking is to remove only the insulating coating layer to match the shape of the symbol, or to carve the outer surface of the outer case together with the insulating coating layer to match the shape of the symbol, there is a problem that the outer surface of the outer case is exposed to the outside at the marking location.

If the outer surface of the exterior case is exposed to the outside at the location where the markings are to be displayed, the markings will not disappear, but the exposed parts will corrode or discolor, deteriorating their appearance. Furthermore, if the exposed parts corrode or discolor, there is a risk that the product information of the electronic parts cannot be mechanically read, for example, using a camera and OCR processing. This not only deteriorates the appearance, but also reduces the efficiency of inspection of the electronic parts.

Furthermore, when the outer surface of the exterior case is carved to match the shape of the symbol along with the insulating coating layer, further problems can arise. That is, if the sputtered particles that are generated when the exterior case is cut with laser light cannot be removed by cleaning, there is a risk that the sputtered particles will fall into the mounted circuitry and cause a short circuit.

The present invention aims to solve the above problems by providing an electronic component and a method for manufacturing the electronic component that suppresses corrosion and discoloration of the display and prevents short circuits caused by sputtered particles.

To achieve the above object, the electronic component according to the present invention is characterized by comprising a metal exterior case, an insulating coating layer covering the exterior case, a groove formed on the outer surface of the exterior case and having an opening covered by the insulating coating layer, and metal particles adhering to the surface of the insulating coating layer facing the groove.

The grooves may be formed by laser irradiation, and the metal particles may be separated from the metal case and attached to the insulating coating layer.

The opening may be blocked by the insulating coating layer to form a closed space inside the groove.

To achieve the above object, the method for manufacturing an electronic component according to the present invention is a method for manufacturing an electronic component having a metal exterior case whose outer surface is covered with an insulating coating layer, and includes a marking step in which a laser beam that penetrates the insulating coating layer is irradiated onto the outer surface of the exterior case to form a groove that forms a marking, and the marking step is characterized in that sputtered particles generated within the groove are attached to the surface of the insulating coating layer facing the groove.

In the marking process, the sputtered particles may be stirred up by the scanning speed of the laser light.

The metal particles or sputtered particles may be attached to 80% or more of the area covering the grooves of the insulating coating layer.

The metal particles or sputtered particles may have an average particle size of 10 μm or less.

The metal particles adhering to the surface of the insulating coating layer facing the closed space may be a part or all of the total metal particles confined in the closed space. The sputtered particles adhering to the surface of the insulating coating layer facing the closed space may be a part or all of the total sputtered particles confined in the closed space.

The electronic component may be a capacitor, a capacitor, or a battery.

According to the present invention, since the laser groove portion is covered with an insulating coating layer, it is possible to prevent corrosion and discoloration of the display formed on the electronic component. In addition, when forming the laser groove portion, there is no need to adopt processing conditions that expand the insulating coating layer, and it is possible to avoid a situation in which the insulating coating layer gets caught on some structure and breaks, causing internal sputtered particles to fall onto the mounted circuit and cause a short circuit.

FIG. 2 is a side view of the capacitor according to the embodiment, partially cut away to show the internal structure. 1 is an external perspective view of a capacitor according to an embodiment of the present invention; 4 is a cross-sectional view of an indication formed on an exterior case. FIG. 1 is a schematic diagram showing the optical path of light entering a display formed on an exterior case. FIG. This is a photograph of the display.

The following describes in detail the capacitor and manufacturing method according to an embodiment of the present invention. Note that the present invention is not limited to the embodiment described below.

The capacitor 1 shown in FIG. 1 is an example of an electronic component, and is a lead-type and wound-type electrolytic capacitor. The capacitor 1 includes an element 2. The element 2 is a component that performs the main function required of an electronic component. In the case of the capacitor 1, the element 2 stores and discharges electric charge by electrostatic capacitance. In the case of the capacitor 1, the element 2 includes a long anode foil, a cathode foil, and an electrolyte. The anode foil and the cathode foil are stacked facing each other with a separator interposed between them, and are wound. The electrolyte is sandwiched between the anode foil and the cathode foil. At least the surface of the anode foil is enlarged, and a dielectric oxide film is further formed.

The capacitor 1 includes an element 2, an outer case 3, lead terminals 4, and a sealing body 6. The outer case 3 is a bottomed cylindrical body with one end open, and houses the element 2. The sealing body 6 is, for example, a rubber or a laminate of rubber and a hard substrate, and is fitted into the outer case 3 with the element 2 housed in the outer case 3, sealing the opening of the outer case 3. The sealing body 6 is fixed to the opening position of the outer case 3 by crimping the periphery of the outer case 3. The lead terminals 4 are connected to the anode foil and cathode foil of the element 2 by stitch connection, cold weld connection, ultrasonic welding, laser welding, or the like, and are drawn out from the sealing body 6. The lead terminals 4 are contact points with the circuit on which the capacitor 1 is mounted, and are electrically connected to the circuit board by reflow soldering or the like when the capacitor 1 is mounted.

As shown in FIG. 2, the capacitor 1 has a marking 5 formed thereon that is visible from the outside. For example, the marking 5 is formed on the bottom surface 31 of the exterior case 3. The bottom surface 31 is the end surface opposite the end surface that is sealed with the sealing body 6 and from which the lead terminals 4 protrude. The marking 5 is a means of informing the product information of the capacitor 1, and is made up of letters, numbers, figures, patterns, and other symbols, and indicates the polarity, rated voltage, capacitance, trademark, serial number, etc.

Figure 3 is a cross-sectional view of the outer surface of the outer case 3 on which the markings 5 are formed. The outer case 3 is made of metal, such as aluminum, an aluminum alloy containing aluminum and manganese, or stainless steel. The outer surface of the outer case 3 is covered with a transparent insulating coating layer 32. The outer surface of the outer case 3 is visible through the insulating coating layer 32. The insulating coating layer 32 prevents the outer case 3 from coming into contact with the current-carrying parts of the circuit or other components on the circuit and causing a short circuit, and also protects the outer case 3 from corrosion or discoloration from the external environment.

This insulating coating layer 32 is made of resin, such as polyethylene terephthalate (PET), epoxy resin, or nylon. In addition, the insulating coating layer 32 preferably has a transmittance of 80% or more for each wavelength of the laser light used in the marking process described below. If the transmittance is less than 80%, the insulating coating layer 32 will absorb the laser light and will tend to be removed by heat generation.

The marking 5 is formed by a groove 51 formed on the outer surface of the exterior case 3. The groove 51 is a groove dug into the outer surface of the exterior case 3. The opening of this groove 51 is blocked by the insulating coating layer 32 that covers the groove 51, and the groove 51 is surrounded by the insulating coating layer 32 to form a closed space.

A large number of metal particles 52 are trapped in the groove 51 closed by the insulating coating layer 32. The metal particles 52 are generated when the groove 51 is formed and are separated from the exterior case 3. The average particle size of the metal particles 52 is 10 μm or less. All or a part of the metal particles 52 trapped in the groove 51 are attached to the area of the insulating coating layer 32 that covers the groove 51. The metal particles 52 are also attached to the surface of the insulating coating layer 32 that faces the groove 51, that is, the inner surface side of the insulating coating layer 32 that faces the groove 51. The metal particles 52 are attached to 80% or more of the area where the insulating coating layer 32 covers the groove 51.

In the manufacturing process, the exterior case 3 is covered with an insulating coating layer 32 before the marking process in which the indicia 5 is formed. In the marking process, a groove 51 is formed without breaking the insulating coating layer 32, and the insulating coating layer 32 is left to remain directly above the groove 51. That is, in the marking process, this groove 51 is processed using laser light that penetrates the insulating coating layer 32 and reaches the outer surface of the exterior case 3.

The laser light forms grooves 51 by melting and sublimating the outer surface of the exterior case 3 with heat without destroying the insulating coating layer 32, and has a wavelength that is transmitted through the insulating coating layer 32 and absorbed by the outer surface of the exterior case 3. In order to transmit the laser light without destroying the insulating coating layer 32 and form grooves 51 in the exterior case 3, for example, a fiber laser, _YVO4 laser, UV laser, YAG laser, etc. are selected, and the beam profile, such as the output, pulse width, scan speed, pulse frequency, spot size, etc., is adjusted in advance.

The metal particles 52 are generated in the marking process and are confined in the closed space of the groove portion 51 closed by the insulating coating layer 32. In addition to confining the metal particles 52, when forming the groove portion 51, the scanning speed of the laser light is increased to make some or all of the metal particles 52 fly up to reach the insulating coating layer 32 and adhere to the insulating coating layer 32.

These metal particles 52 are sputtered particles that melt when the outer surface of the exterior case 3 receives the energy of the laser light when irradiated with the laser light. Vapor gas is also generated in the grooves 51 that are cut by irradiating with the laser light. The molten metal is blown away by this vapor gas and separated into particles from the exterior case 3, which cool and solidify, remaining as metal particles 52.

Some of the generated metal particles 52 may remain on the inner surface of the groove 51. Also, when the laser light is irradiated, some of the metal that melts when the outer surface of the exterior case 3 receives the energy of the laser light may extend and cool and harden without leaving the exterior case 3, remaining in the closed space of the groove 51 as a burr. The burr may also separate from the inner surface of the groove 51 over time.

As shown in FIG. 4, such a display 5 appears as light and dark on the outer surface of the outer case 3 and the groove 51 due to the difference between the amount of light reflected from the outer surface of the outer case 3 and entering the human retina or the image sensor of the camera, and the amount of light reflected from the inner surface of the groove 51 and entering the human retina or the image sensor of the camera.

Figure 4 is a schematic diagram showing the optical path of light entering the display formed on the exterior case 3. As shown in Figure 4, the metal particles 52 have a surface that is more distorted than the outer surface of the exterior case 3. A portion of the light heading toward the groove portion 51 hits the metal particles 52 attached to the insulating coating layer 32, and is reflected more diffusely than the outer surface of the exterior case 3.

The other light heading toward the groove 51 passes between the metal particles 52 attached to the insulating coating layer 32, reaches the inner surface of the groove 51, and is reflected. A portion of the light that is reflected by the inner surface of the groove 51 and attempts to exit the groove 51 is blocked by the metal particles 52 attached to the insulating coating layer 32.

That is, the metal particles 52 attached to the insulating coating layer 32 act as a light shield that blocks light attempting to exit from the grooves 51 that form the display 5. The insulating coating layer 32 acts as a holder that separates the metal particles 52 that act as light shields from the inner surface of the grooves 51. The insulating coating layer 32 and the metal particles 52 act as a light shield that faces the inner surface of the grooves 51 at a distance.

In this way, the amount of light entering the groove 51 is reduced by the metal particles 52, and the metal particles 52 also block the reflected light from the groove 51, so that the amount of light reaching the human retina or the image sensor of the camera from the display 5 is lower than the amount of light reflected from the outer surface of the exterior case 3.

Here, the visibility and distinguishability of the marking 5 can also be achieved by deepening the grooves 51 or roughening them thoroughly. This is because as the grooves 51 become deeper, less light hits the grooves 51, and the exposed grooves 51 cause more diffuse reflection. However, to dig the grooves 51 deeper, the amount of energy projection of the laser light must be increased. When the amount of energy projection of the laser light is increased, the internal pressure of the grooves 51 increases due to heat, causing the insulating coating layer 32 to bulge.

The bulging insulating coating layer 32 may get caught on an external structure or the like and tear during the process of mounting the capacitor 1. If the insulating coating layer 32 tears, the metal particles 52 inside may fall from the groove 51 onto the mounting circuit, causing a short circuit in the mounting circuit.

On the other hand, this display 5 achieves a reduction in the amount of light by metal particles 52 that adhere to the insulating coating layer 32. Therefore, the groove portion 51 can be shallow, and the amount of energy projection of the laser light can be reduced. Therefore, the insulating coating layer 32 can be kept flat without bulging.

When the output of the laser light is reduced and the scanning speed of the laser light is increased so that metal particles 52 with an average particle size of 10 μm or less are generated, the metal particles 52 are not taken into the laser-irradiated portion melted by the laser, and the metal particles 52 easily fly up and adhere to the insulating coating layer 32. In other words, when the output of the laser light is reduced and the scanning speed of the laser light is increased so that metal particles 52 with an average particle size of 10 μm or less are generated, the expansion of the insulating coating layer 32 can be suppressed.

An example of a beam profile that causes the metal particles 52 to fly up is shown. The capacitor 1 of Example 1 has an exterior case 3 made of aluminum with an aluminum number of A1100. The insulating coating layer 32 is polyethylene terephthalate, and the resin thickness is 8 μm. A _YVO4 laser device with a wavelength of 1064 nm was used as the device for irradiating the laser light. The scanning speed of the laser light was set to 2200 mm/sec so that the metal particles 52 fly up. In addition, the depth of the groove portion 51 was set to 10 μm, and the output of the laser light was adjusted so that the average particle size of the generated metal particles 52 was 10 μm or less.

Comparative Example 1 was used to fabricate a capacitor in comparison with Example 1. The material of the exterior case 3, the material and resin thickness of the insulating coating layer 32, and the device for irradiating the laser light were the same. However, the scanning speed was reduced to 200 mm/sec, which is less than one-tenth of the scanning speed of Example 1, so as to prevent the metal particles 52 from flying up. The output of the laser light was adjusted so that the depth of the grooves forming the display was 50 μm, five times that of Example 1.

In FIG. 5, (a) is a photograph taken before the insulating coating layer 32 of Comparative Example 1 was peeled off, (b) is a photograph taken after the insulating coating layer 32 of Comparative Example 1 was peeled off, (c) is a photograph taken before the insulating coating layer 32 of Example 1 was peeled off, and (d) is a photograph taken after the insulating coating layer 32 of Example 1 was peeled off.

As shown in Figure 5, the difference in brightness of the display 5 before and after peeling of the insulating coating layer 32 in Example 1 is greater than the difference in brightness of the display before and after peeling of the insulating coating layer 32 in Comparative Example 1. This fact indicates that in Example 1, the metal particles 52 are lost due to peeling of the insulating coating layer 32, and the benefit of the distinguishability provided by the metal particles 52 is no longer available. On the other hand, in Comparative Example 1, there is no or only a small amount of adhesion of the metal particles 52 to the insulating coating layer 32, so there is no benefit of the metal particles 52 to begin with, and the distinguishability does not change much.

The difference between Example 1 and Comparative Example 1 is the output of the laser light and the scanning speed of the laser light. It was confirmed that by increasing the scanning speed of the laser light, the metal particles 52 generated during the formation of the groove portion 51 can be stirred up and attached to the insulating coating layer 32. It was also confirmed that by decreasing the laser output to reduce the diameter of the metal particles 52, the metal particles 52 can be easily stirred up simply by increasing the scanning speed of the laser light within an effective range.

As described above, the capacitor 1 has a metal exterior case 3 covered with an insulating coating layer 32, and a groove 51 with an opening covered by the insulating coating layer 32 formed on the outer surface of the exterior case 3. The capacitor 1 is provided with metal particles 52 that adhere to the surface of the insulating coating layer 32 on the side of the groove 51.

For example, this capacitor 1 has a metal exterior case 3 covered with an insulating coating layer 32, and is provided with a groove 51 on the outer surface of the exterior case 3 that forms the display 5. The opening of the groove 51 is blocked by the insulating coating layer 32, forming a closed space. This closed space is provided with metal particles 52 that adhere to the surface of the insulating coating layer 32 facing the closed space.

This allows light to be repeatedly reflected between the metal particles 52 attached to the insulating coating layer 32 and the inner surface of the groove 51, reducing the amount of light through light absorption, scattering, and attenuation. This allows the laser cut portion 51 to be shallower and the amount of laser light energy projection to be reduced, preventing an increase in the internal pressure of the groove 51 and suppressing the expansion of the insulating coating layer 32. This reduces the risk of the insulating coating layer 32 getting caught on an external structure or the like and breaking, and prevents a short circuit caused by the metal particles 52 falling off the mounted circuit.

The indicia 5 is covered by the insulating coating layer 32 and is not exposed, which suppresses corrosion and discoloration of the indicia 5 and maintains a good appearance. In addition, the indicia 5 is not exposed and is suppressed from corroding and discoloring, which makes it easier to read mechanically and improves the inspection efficiency of the capacitor 1.

The closed space within the groove portion 51 is sufficient if it can confine the metal particles 52, and it is acceptable for holes or cracks to be formed that are large enough to prevent the metal particles 52 from being expelled from the insulating coating layer 32.

The manufacturing method of this capacitor 1 also includes a marking process in which a laser beam that penetrates the insulating coating layer 32 is irradiated onto the outer surface of the outer case 3 to form a groove 51 that forms the display 5. In this marking process, metal particles 52 generated within the groove 51 are stirred up and attached to the surface of the insulating coating layer 32 facing the groove 51. This makes it possible to easily prevent short circuits caused by the falling off of the metal particles 52 and to suppress corrosion and discoloration of the display 5.

In addition, in the marking process, the metal particles 52 are stirred up by the scanning speed of the laser light. This makes it possible to easily prevent short circuits caused by falling off of the metal particles 52 and to suppress corrosion and discoloration of the display 5 without increasing or decreasing the number of steps of forming the display 5 with the laser light. In addition, metal particles 52 with an average particle size of 10 μm or less are generated. This makes it possible to easily cause the metal particles 52 to fly up by increasing the scanning speed of the laser light, making it possible to even more easily prevent short circuits caused by falling off of the metal particles 52 and to suppress corrosion and discoloration of the display 5 without increasing or decreasing the number of steps of forming the display 5 with the laser light.

As described above, the capacitor 1 has been described as an example of an electronic component, but this is not limiting. As long as the electronic component has a metal exterior case 3 and a display 5 formed by a groove 51 provided on the outer surface of the exterior case 3, it is possible to easily prevent short circuits caused by falling off of metal particles 52 and suppress corrosion and discoloration of the display 5. Any electronic component having a metal exterior case 3 can be used, and examples of such electronic components include, in addition to the capacitor 1, a capacitor, a battery, a coil, a transformer, etc.

REFERENCE SIGNS LIST 1 Capacitor 2 Element 3 Outer case 31 Bottom surface 32 Insulating coating layer 4 Lead terminal 5 Indication 51 Groove portion 52 Sputtered particle 6 Sealing body

Claims (12)

A metal outer case,
an insulating coating layer covering the exterior case;
a groove formed on an outer surface of the exterior case, the groove having an opening covered with the insulating coating layer;
metal particles attached to the groove-side surface of the insulating coating layer in a state separated from the groove;
To have
An electronic component characterized by: The groove portion is formed by laser irradiation,
the metal particles are separated from the exterior case and attached to the insulating coating layer;
2. The electronic component according to claim 1 . a closed space is formed inside the groove by closing the opening with the insulating coating layer;
3. The electronic component according to claim 1 or 2. the metal particles are attached to an area of 80% or more of the region covering the groove of the insulating coating layer;
4. The electronic component according to claim 1, wherein The metal particles have an average particle size of 10 μm or less.
3. The electronic component according to claim 1 or 2. the metal particles adhering to the insulating coating layer are a part or all of the total metal particles confined in the space covering the groove portion;
6. The electronic component according to claim 1, wherein being a capacitor, a condenser or a battery;
7. The electronic component according to claim 1, wherein A method for manufacturing an electronic component having a metal exterior case whose outer surface is covered with an insulating coating layer, comprising the steps of:
a marking step of irradiating an outer surface of the outer case with a laser beam that transmits through the insulating coating layer, thereby forming a groove that forms a marking;
In the marking step, sputtered particles generated within the groove are attached to a surface of the insulating coating layer facing the groove in a state separated from the groove;
A method for manufacturing an electronic component, comprising the steps of: In the marking step, the sputtered particles are stirred up by a scanning speed of a laser beam;
The method for producing an electronic component according to claim 8, further comprising the steps of: In the marking step, the sputtered particles are attached to an area of 80% or more of a region covering the groove portion of the insulating coating layer;
The method for manufacturing an electronic component according to claim 8 or 9, In the marking step, the sputtered particles are generated to have an average particle size of 10 μm or less;
11. The method for manufacturing an electronic component according to claim 8, further comprising the steps of: The electronic component is a capacitor or a battery;
12. The method for manufacturing an electronic component according to claim 8, further comprising the steps of:

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