JP7632173B2 - Resin-sealed electronic substrate and method for manufacturing the same - Google Patents

Description

The present invention relates to a resin-sealed electronic substrate and a method for manufacturing the resin-sealed electronic substrate.

The following Patent Document 1 describes a resin-sealed semiconductor device such as a power transistor or diode, in which a metal support plate on which a semiconductor chip is mounted is covered with insulating resin. Conventionally, including Patent Document 1 below, has been carried out on resin-sealed electronic boards in which a board on which electronic components are mounted is covered with resin, and methods for manufacturing such resin-sealed electronic boards.

Japanese Patent Application Publication No. 5-109795

In a resin-sealed electronic board as described in Patent Document 1, electronic components are mounted on a board by soldering, and the board is then held in a molding die, after which heated and molten insulating resin is poured onto the board to manufacture it. Therefore, if an electronic component has two or more terminals, each of which is secured by solder, the solder securing the terminals may melt due to the insulating resin that is poured in, and the molten solder pieces may come into contact with each other, causing a short circuit.

The present invention was made in consideration of such circumstances, and aims to prevent short circuits between two terminals of an electronic component on a board during the manufacture of a resin-sealed electronic board.

In order to solve the above problems, the resin-sealed electronic substrate of the present invention comprises:
an electronic component having two terminals;
a substrate having two lands provided on a first surface thereof, on which the two terminals of the electronic component are mounted, and a through hole formed between the two lands;
a coating layer made of an insulating resin and coating the first surface of the substrate;
The substrate is characterized in that it is provided with a second surface side molding body made of insulating resin on the second surface side, which is the surface opposite to the first surface, of the substrate, and formed in a manner filling the through hole.

When manufacturing a resin-sealed electronic board of this configuration, before forming the coating layer, insulating resin is filled between the two lands formed on the board through the through hole to form the second surface side molded body. This prevents the lands from coming into contact even if the solder on the lands melts when the coating layer is formed, and reliably prevents a short circuit between the two terminals of the electronic component. In a resin-sealed electronic board of this configuration, the electronic components are not particularly limited, and various types can be used. In addition, a resin-sealed electronic board of this configuration can also be used when it is equipped with an electronic component with three or more terminals.

In the above configuration, the two-sided molded body can be configured to cover the entire substrate, with a design shape being applied to the surface opposite the substrate.

This resin-sealed electronic board is configured so that the second surface side molded body functions as a housing to accommodate the board, and the surface of the second surface side molded body can be used as a design surface for an interior material. With this resin-sealed electronic board, there is no need to assemble the electronic board with a housing or interior material, which reduces the number of parts and the labor required.

In the above configuration, the electronic component is an LED element that emits light, the substrate, the covering layer, and the second surface side molded body are molded from a resin having optical transparency, the second surface side molded body has a lens portion that emits light, and the covering layer is provided with a light reflecting portion that reflects the light emitted from the LED element toward the lens portion of the second surface side molded body.

A resin-sealed electronic board with this configuration can be partially used as lighting. Since the board and lens member are integrated in this resin-sealed electronic board, it is possible to reduce the number of parts and the number of labor hours. If the second surface side molded body is configured to cover the entire board and function as a housing, the resin-sealed board itself becomes a lighting device. In other words, there is no need to assemble lens members, housing members, etc. to the board on which the LED elements are mounted, as in conventional lighting devices, and it is possible to further reduce the number of parts and the number of labor hours.

In the above configuration, the substrate can be a flexible film-like substrate.

This type of resin-sealed electronic board can be curved when molding the second surface side molded body and the coating layer, making it possible to realize not only flat but also three-dimensional shapes.

In order to solve the above problems, the present invention provides a method for producing a resin-sealed electronic substrate, comprising the steps of:
A method for manufacturing a resin-sealed electronic substrate comprising: an electronic component having two terminals; a substrate having the electronic component mounted on a first surface thereof by soldering; and a coating layer made of insulating resin and coating the first surface of the substrate, the method comprising the steps of:
the substrate has two lands provided on the first surface, on which the two terminals of the electronic component are mounted, and a through hole formed between the two lands;
a second surface side molded body molding step of holding the substrate on which the electronic components are mounted within a mold, forming a second surface side molding space including the through hole as a part thereof between the mold and a second surface, which is a surface of the substrate opposite to the first surface, and filling and solidifying a molten insulating resin into the second surface side molding space to mold a second surface side molded body;
a coating layer forming step, which is performed after the back surface side molding step, of forming a first surface side molding space between the first surface and the mold, filling the first surface side molding space with a molten insulating resin and solidifying it to form the coating layer;
The present invention is characterized by comprising:

This method of manufacturing a resin-sealed electronic board allows the through-hole to be filled before the coating layer is formed, making it possible to manufacture a resin-sealed electronic board that reliably prevents short circuits between the two terminals of the electronic component.

According to the present invention, it is possible to prevent short circuits between two terminals of an electronic component on a board during the manufacture of a resin-sealed electronic board.

FIG. 1 is a diagram showing the interior of a vehicle in which a resin-sealed substrate according to an embodiment of the present invention is used; A cross-sectional view of a main part of a map lamp, which is a resin-sealed substrate according to this embodiment. A cross-sectional view of the main part of the center lamp, which is a resin-sealed substrate of this embodiment. FIG. 13 is a diagram showing a second surface side molding step in the manufacturing method of the resin-sealed substrate of the present embodiment. FIG. 1 is a diagram showing a coating layer forming step in the manufacturing method of the resin-sealed substrate according to the present embodiment.

Below, examples of the present invention will be described in detail with reference to the drawings as a form for carrying out the present invention. Note that the present invention is not limited to the following examples, and can be carried out in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

The resin-sealed electronic board according to the embodiment of the present invention is used in lighting devices 10, 12 mounted on a vehicle. As shown in FIG. 1, these lighting devices 10, 12 form part of an overhead module 16 that is provided on the ceiling 14 of the vehicle and extends in the fore-and-aft direction of the vehicle. The lighting device 10 is a map lamp (hereinafter referred to as "map lamp 10") located at the front end of the overhead module 16, on the front side of the ceiling 14, and has two spot lights 10R, 10L corresponding to the driver's seat and passenger seat, respectively. The lighting device 12 is a center lamp (hereinafter referred to as "center lamp 12") located at the rear end of the overhead module 16, near the center of the vehicle interior on the ceiling 14.

2, the map lamp 10 is configured such that a film substrate 22 on which an LED element 20, which is a light source, is mounted is sealed with resin. In detail, the map lamp 10 is configured to include an LED element 20 as an electronic component (two are provided for each of the driver's seat and the passenger seat, but only one is shown in FIG. 2), a film substrate 22 on which the LED element 20 is mounted, a first surface side molded body 24 molded with resin so as to cover the first surface 22A of the film substrate 22 on which the LED element 20 is mounted, and a second surface side molded body 26 molded with resin so as to cover the second surface 22B of the film substrate 22, which is the surface opposite to the first surface 22A. Although not shown, a driver for driving the LED element 20, a capacitor chip, and a connector for connecting to the vehicle's electric circuit are also mounted on the first surface 22A of the film substrate 22.

The film substrate 22 is mainly composed of a substrate body 30 made of polyethylene terephthalate (PET), which is almost colorless and transparent and has optical transparency. On one side of the substrate body 30, a wiring pattern is formed with copper foil, and lands 32 for soldering each electronic component are formed. In other words, the surface of the substrate body 30 on which the wiring pattern and lands are formed is the first surface 22A. For example, as shown in FIG. 2, two lands 32 are provided corresponding to the two terminals of the LED element 20, the anode 20a and the cathode 20k. The anode 20a and the cathode 20k are fixed to their respective lands 32 by solder 34.

In addition, a through hole 36 is formed between the two lands 32 in the film substrate 22. The size of this through hole 36 is set to a size that fits within the body 21 of the LED element 20 when viewed from above. The shape of the through hole 36 is not particularly limited, but in this embodiment, when the LED element 20 is mounted on the first surface 22A of the film substrate 22, the dimension in the direction intersecting the direction connecting the lands 32 from the view point of the first surface 22A side is set to be approximately the same as the width of the body 21 of the LED element 20 at its largest point. In addition, a similar through hole is formed in the film substrate 22 at the location where another LED element 20 is mounted, and a through hole is also formed between the lands to which the anode and cathode of other electronic components are connected.

The first surface side molded body 24 and the second surface side molded body 26 are made of an insulating resin material, such as acrylic or polycarbonate, that has a refractive index sufficiently higher than that of air and is almost transparent (excellent light transmission). The first surface side molded body 24 is a coating layer formed to cover the entire first surface 22A for the purpose of protecting the wiring pattern and electronic components on the film substrate 22. Similarly to the first surface side molded body 24, the second surface side molded body 26 is also formed to cover the entire second surface 22B of the film substrate 22. In other words, the second surface side molded body 26 is formed in such a way that it fills the through-hole 36 formed in the film substrate 22.

The second surface side molded body 26 has a convex lens portion 40 that bulges downward, or more simply, below the LED element 20, formed at a location where it overlaps with the LED element 20 on the film substrate 22 in the thickness direction of the film substrate 22. On the other hand, the first surface side molded body 24 has a recess formed on its upper surface (the surface opposite the film substrate 22), forming a light reflecting portion 42 that reflects light emitted upward from the LED element 20 downward, or more specifically, toward the lens portion 40 of the second surface side molded body 26.

The center lamp 12 is similar in configuration to the map lamp 10, and includes a film substrate 52 on which an LED element 50 is mounted, a first surface side molded body 54 molded from resin so as to cover the first surface 52A of the film substrate 52 on which the LED element 50 is mounted, and a second surface side molded body 56 molded from resin so as to cover the second surface 52B of the film substrate 52 on the opposite side to the first surface 52A. However, the shapes of the first surface side molded body 54 and the second surface side molded body 56 differ from those of the map lamp 10.

In the center lamp 12, the second surface side molding 56 has an uneven shape 58 formed on almost the entire lower surface side. On the other hand, the first surface side molding 54 has a light reflecting portion 60 that reflects light downward on the entire area corresponding to the uneven shape 58 of the second surface side molding 56 on the upper surface, and can guide the light of the LED element 50 and direct it downward. In other words, the center lamp 12 is configured so that light is emitted from the entire portion where the uneven shape 58 of the second surface side molding 56 is formed.

In the center lamp 12, like the map lamp 10, the film substrate 52 has two lands 62 corresponding to the two terminals of the LED element 50, the anode 50a and the cathode 50k, and has a through hole 64 between the two lands 62, and the second surface side molded body 56 is formed by filling the through hole 64.

Next, the manufacturing method of the resin-sealed electronic board of the present invention will be described using the above-mentioned map lamp 10 as an example. First, a circuit board S is prepared on which electronic components including an LED element 20 are mounted on a film substrate 22 having the above-mentioned through hole 36 formed therein. Then, the circuit board S is held in a first molding die 80 of an injection molding device shown in FIG. 4. The first molding die 80 is mainly composed of a pair of metal dies 82, 84, and is used to mold the above-mentioned second surface side molded body 26.

The upper die 82 of the pair of dies 82, 84 is a fixed die that is fixedly installed, and the lower die 84 is a movable die that can be moved up and down by a drive device. The fixed die 82 has a molding surface 82A on the lower side that imitates the surface of the second surface side molded body 26 of the circuit board S (the lower surface in FIG. 2), and the movable die 84 has a molding surface 84A on the upper side that imitates the shape of the first surface 22A side of the circuit board S. The molding surface 84A of the movable die 84 is then held in a state in which the first surface 22A side of the circuit board S faces downward. Next, the pair of dies 82, 84 are closed to form a molding space for molding the second surface side molded body 26, that is, a second surface side molding space C2, between the molding surface 82A and the second surface 22B of the circuit board S, as shown in FIG. 4.

Then, an injection device provided on the fixed mold 82 side is configured to pour molten insulating resin material (acrylic or polycarbonate) into the second surface side molding space C2, forming the second surface side molded body 26. In other words, the second surface side molded body 26 is molded in such a way that it fills the space formed by the through-hole 36 formed in the film substrate 22 and the LED element 20.

Next, the molding of the first surface side molded body 24 is performed using the second mold 90 shown in FIG. 5. The second mold 90 is mainly composed of a pair of molds 92, 94, with the upper mold 92 being the fixed mold and the lower mold 94 being the movable mold. The fixed mold 92 has a molding surface 92A formed on the lower surface thereof that imitates the shape of the surface (upper surface in FIG. 2) of the first surface side molded body 24, and the movable mold 94 has a molding surface 94A formed on the upper surface thereof that imitates the surface (lower surface in FIG. 2) of the second surface side molded body 26. The circuit board S on which the second surface side molded body 26 has been molded is held in a state in which the second surface side molded body 26 fits into the molding surface 94A of the movable mold 94. Next, the pair of molds 92, 94 are closed to form a molding space for molding the first surface side molded body 24, that is, a first surface side molding space C1, between the molding surface 92A and the first surface 22A of the circuit board S, as shown in FIG. 4.

Then, an injection device provided on the fixed mold 92 side is configured to pour molten insulating resin material (acrylic or polycarbonate) into the first surface side molding space C1, and the first surface side molded body 24 is molded. In other words, the manufacturing method of the resin-sealed electronic substrate of this embodiment includes a second surface side molded body molding process for molding the second surface side molded body 26, and a first surface side molding process (coating layer molding process) that is performed after the second surface side molded body molding process and for molding the first surface side molded body 24 as a coating layer.

In conventional resin-sealed electronic boards, when filling the molding space with molten insulating resin to form the coating layer, the solder that has fixed the LED elements, etc., melts and flows along with the molten resin, and for example, the solder that fixed the anode and the solder that fixed the cathode may come into contact with each other, causing a short circuit. In contrast, according to the manufacturing method of this embodiment, the second surface side molded body 26 is molded by filling the space formed by the through hole 36 formed in the film substrate 22 and the LED element 20, so that even if the solder 34 that fixed the anode 20a and the solder 34 that fixed the cathode 20k melt, it is possible to avoid a situation where they come into contact with each other. In addition, since the first surface side molded body 24 and the second surface side molded body 26 are molded by injection molding, they can be molded relatively freely, as in the map lamp 10 and center lamp 12 of this embodiment, so the resin-sealed electronic board itself can have various functions.

The map lamp 10 (center lamp 12), which is a resin-sealed electronic board of this embodiment, includes an electronic component 20 (50) having two terminals 20a, 20k (50a, 50k), two lands 32 (62) provided on the first surface 22A (52A) and on which the two terminals 20a, 20k (50a, 50k) of the electronic component 20 (50) are mounted, and a through hole 36 formed between the two lands 32 (62). (64), a coating layer 24 (54) made of insulating resin that coats the first surface 22A (52A) of the substrate 22 (52), and a second surface side molded body 26 (56) made of insulating resin on the second surface 22B (52B) side, which is the surface opposite to the first surface 22A (52A) of the substrate 22 (52), and formed in a form that fills the through hole 36 (64).

In other words, while the map lamp 10 and center lamp 12 in this embodiment are resin-sealed electronic boards, they function as lighting devices using only the components of the resin-sealed electronic boards. In addition, the map lamp 10 and center lamp 12 are configured with the circuit board and lens member of the lighting device integrated together, so there is no need to assemble a lens member to a circuit board on which LED elements are mounted, as in conventional lighting devices, and this reduces the number of parts in the lighting device and the labor required.

<Other embodiments>
(1) In the above embodiment, the second surface side molded body 26 covers the entire film substrate 22, and the surface opposite the film substrate 22 is the design surface, but the second surface side molded body may be formed so as to fill the through hole 36 formed in the film substrate 22. For example, only the lens portion 40 of the map lamp 10 may be molded, and in such a case, the above-mentioned short circuit between the terminals can be prevented.
(2) In addition, the resin-sealed electronic board in the above embodiment is used as a lighting device, but is not limited thereto. For example, the surface of the second surface side molded body may be molded as a design surface, and the electronic board may be integrated into an interior material for a vehicle.
(3) In the above embodiment, the main substrate of the resin-sealed electronic substrate is a flexible film-like substrate, and is sealed with resin while remaining flat. However, the substrate may be sealed with resin in a curved state. The present invention may also be applied to rigid substrates.

10...Map lamp (resin-sealed electronic board), 12...Center lamp (resin-sealed electronic board), 20...LED element (electronic component), 20a...Anode (terminal), 20k...Cathode (terminal), 22...Film substrate (substrate), 22A...First surface, 22B...Second surface, 24...First surface side molded body (coating layer), 26...Second surface side molded body, 32...Land, 34...Solder, 36...Through hole, 40...Lens portion, 42...light reflecting portion, 50...LED element [electronic component], 50a...anode [terminal], 50k...cathode [terminal], 52...film substrate [substrate], 52A...first surface, 52B...second surface, 54...first surface side molded body [covering layer], 56...second surface side molded body, 60...light reflecting portion, 62...land, 64...through hole, 80...first mold, 90...second mold, C1...first surface side molding space, C2...second surface side molding space

Claims (4)

an electronic component having two terminals;
a substrate having two lands provided on a first surface thereof, on which the two terminals of the electronic component are mounted, and a through hole formed between the two lands;
a coating layer made of an insulating resin and coating the first surface of the substrate;
a second surface side molded body formed of an insulating resin on a second surface side of the substrate, the second surface side being the surface opposite to the first surface, and formed in a manner to fill the through hole;
Equipped with
The second surface side molded body covers the entire substrate, and a design shape is formed on the surface opposite to the substrate, in a resin-sealed electronic substrate. an electronic component having two terminals;
a substrate having two lands provided on a first surface thereof, on which the two terminals of the electronic component are mounted, and a through hole formed between the two lands;
a coating layer made of an insulating resin and coating the first surface of the substrate;
a second surface side molded body formed of an insulating resin on a second surface side of the substrate, the second surface side being the surface opposite to the first surface, and formed in a manner to fill the through hole;
Equipped with
the electronic component is an LED element that emits light,
the substrate, the covering layer, and the second surface side molded body are molded from a resin having optical transparency,
The second surface side molded body has a lens portion that emits light,
The cover layer is provided with a light reflecting portion that reflects light emitted from the LED element toward the lens portion of the second surface side molded body. an electronic component having two terminals;
a substrate having two lands provided on a first surface thereof, on which the two terminals of the electronic component are mounted, and a through hole formed between the two lands;
a coating layer made of an insulating resin and coating the first surface of the substrate;
a second surface side molded body formed of an insulating resin on a second surface side of the substrate, the second surface side being the surface opposite to the first surface, and formed in a manner to fill the through hole;
Equipped with
The substrate is a flexible film-like substrate, that is , a resin-sealed electronic substrate. A method for manufacturing a resin-sealed electronic substrate comprising: an electronic component having two terminals; a substrate having the electronic component mounted on a first surface thereof by soldering; and a coating layer made of insulating resin and coating the first surface of the substrate, the method comprising the steps of:
the substrate has two lands provided on the first surface, on which the two terminals of the electronic component are mounted, and a through hole formed between the two lands;
a second surface side molded body molding step of holding the substrate on which the electronic components are mounted within a mold, forming a second surface side molding space including the through hole as a part thereof between the mold and a second surface, which is a surface of the substrate opposite to the first surface, and filling and solidifying a molten insulating resin into the second surface side molding space to mold a second surface side molded body;
a coating layer forming step, which is carried out after the second surface side molding step, of forming a first surface side molding space between the first surface and the mold, filling the first surface side molding space with a molten insulating resin and solidifying it to form the coating layer;
A method for producing a resin-sealed electronic substrate, comprising:

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