JPH0243058A - Seal structure of substrate - Google Patents

Abstract

PURPOSE:To reduce air bubbles invading in a seal material as low as possible, to enhance the reliability of the seal material and to suitably protect a connection member by filling the gap between substrates with the first seal material to close the same and covering the first seal member and the connection member with the second seal material. CONSTITUTION:In a thermal line head 1, a V-shape groove 5a is formed to the abutted part 5 of an alumina substrate 2 provided on the left side of the free end part of said head 1 and a resin substrate 3 loaded with a driver IC 6 by chamfering the end surface of the resin substrate 3 and filled with a seal material 12 composed of an epoxy resin to be closed. Then, a seal material 11 composed of an epoxy resin is applied so as to cover not only both lead wires 9, 10 and the driver IC 6 on the resin substrate 3 but also the abutted part 5.

Description

[Detailed Description of the Invention] [Object of the Invention] <Industrial Field of Application> The present invention is a method for sealing a substrate for protecting a driver IC, lead wires, etc. mounted on a substrate of a thermal head or an LED array head. The present invention relates to a sealing structure, and particularly to a substrate sealing structure for protecting connecting members such as lead wires connecting a pair of adjacent substrates.

<Prior Art> Conventionally, thermal printers have been known that perform desired printing each time a resistive heating section of a thermal head is brought into sliding contact with, for example, a sheet of paper supported by a platen via a thermal transfer ink ribbon.

In the thermal head mentioned above, an alumina substrate with good heat dissipation is used for the free end side part where the resistance heating part is provided, but in order to reduce the manufacturing cost of the head, this alumina substrate part is used as much as possible. Since it is preferable to make the heat generating part as small as possible, a substrate made of resin, which is inexpensive and has good workability, is provided on the base end side with the end surfaces of both substrates butted against each other, and a resistance heating section is selected on this resin substrate. The device is equipped with electronic components such as a driver IC that generates heat. In this case, it is preferable that the electronic component and the wiring on the alumina substrate or the wiring on the resin substrate and the wiring on the alumina substrate be connected to each other by, for example, wire bonding.

On the other hand, for example, in an LED array printer that prints by selectively lighting up the LED elements of an LED array mounted on an alumina substrate, the L of the print head
The alumina substrate on which the ED array is mounted is made as small as possible, a resin substrate is provided on the base end side so as to abut against the end surface of the substrate, electronic components such as a driver IC are mounted on this resin substrate, It is preferable to connect the component and the wiring on the alumina substrate or the wiring on the resin substrate and the wiring on the alumina substrate to each other by wire bonding or the like.

However, in such a printer head, especially connecting members such as lead wires installed between the above-mentioned two substrates, or electronic components mounted near the abutting portions of both substrates are made of silicone resin or the like. However, even if both boards are processed with high precision, there will still be a gap at the butt part, so sealing from this butt part is done during electronic component sealing work. Air bubbles enter the sealing material, and as the temperature changes during curing of the sealing material, these bubbles change in volume, causing cracks in the sealing material, and in some cases, causing the connection member to break, etc., resulting in damage to its reliability. There was a problem with sexuality.

<Problems to be Solved by the Invention> In view of the problems of the prior art, the main purpose of the present invention is to provide a thermal head, an LED array head, etc., which is constructed between a pair of adjacent substrates. An object of the present invention is to provide a substrate sealing structure that can easily and suitably protect lead wires and the like.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, such an object is to provide a substrate for protecting a connecting member such as a lead wire installed between a pair of mutually adjacent substrates. The sealing structure includes a first sealant that fills a gap between the front and back substrates, and a second sealant that covers the first sealant and the connection member. This is achieved by providing a sealing structure for the substrate.

<Effect> In this way, it is possible to reduce as much as possible the air bubbles that enter the inside of the encapsulant, which improves the reliability of the encapsulant and improves the reliability of the encapsulant. The connecting member can be suitably protected.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show a first embodiment according to the invention. Thermal line head 1, which faces the printing surface of paper (not shown) via an angry heat transfer ink ribbon, has an alumina substrate 2 provided on its free end side, that is, on the left side in FIG. The heat sink 4 has resin substrates 3 disposed adjacent to each other so as to be in close contact with each other, and a heat sink 4 closely attached to the bottoms of these substrates 2.3. A resistive heating section made of a resistive heating element film is provided on the free end side (not shown) of the alumina substrate 2.

In the vicinity of the abutting portion 5 on the resin substrate 3, there is a driver IC for selectively generating heat in the above-mentioned resistance heating element film.
6 is installed. An individual electrode 7 is formed between the driver IC 6 and the resistance heating section, and the individual electrode 7 and the driver IC 6 are connected by a lead wire 9.

The driver IC 6 is also connected to the end of the wiring 8 connected to an external circuit using a lead wire 10. The driver IC 6 and both lead wires 9 and 10 are covered with a sealing material 11 made of epoxy resin, which is not applied by a coating device (not shown), so that they are protected from external disturbances.

Here, as clearly shown in FIG. 2, the abutting portion 5 has
A V-shaped groove 5a is formed by chamfering the end face of the resin substrate 3. The inside of this V-shaped groove 5a is filled with a sealing material 12 which may be an epoxy resin.

Therefore, since the sealing material 11 is applied so as to cover both the lead wires 9 and 10 and the driver IC 6 on the resin substrate 3, and also to cover the butt part 5, air bubbles are removed from the sealing material from the butt part. It is possible that it could infiltrate the inside of 11,
The sealing material 12 filled in the butt portion 5 ensures airtightness of the portion, and the interior of the sealing material 11 is maintained in a suitably degassed state. Incidentally, in practice, the filling sealing material 12 of the abutting portion 5 may be any suitable material that can airtightly seal the abutting portion 5.

FIG. 3 is a diagram similar to FIG. 2 showing a second embodiment based on the present invention.

According to this embodiment, the end face of the butt portion 13 of the resin substrate 3 is processed to be oblique in advance. That is, the end surface of the alumina substrate 2 and the end surface of the resin substrate 3 collide only at the lower end in FIG. 3. The airtightness of the butt portion 13 is ensured by filling the V-shaped groove 13a formed between these end faces with a sealing material 14 similar to that of the first embodiment.

FIG. 4 is a diagram similar to FIG. 2 showing a third embodiment based on the present invention. In this embodiment, the sealing structure based on the present invention is applied to an LED array head of an LED array printer.

The LED array head 21 includes a heat sink 22 made of metal, an alumina substrate 23 mounted on the top of the heat sink 22, and a resin substrate 24 mounted adjacent to the alumina substrate on its base end side, that is, on the right side in FIG. have. An LED array chip 25 is mounted on the alumina substrate 23,
A driver IC 26 is mounted on the resin substrate 24. The LED array chip 25 is connected to the driver IC 26 via a lead wire 27, wiring 28 on the resin substrate 24, and two lead wires. Also, driver IC
26 is also connected by a lead wire 31 to one end of a wiring 30 formed on the base end side of the resin substrate 24, that is, on the right side in FIG. The other end of the wiring 30 is connected to an external circuit (not shown). Note that the reference numeral 33 is a common electrode provided at the bottom of each LED array chip 25.

Here, the alumina substrate 23 and the resin substrate 24 abut each other at the butt portion 34 . By chamfering the end face of the resin substrate 24 at this butt portion 34, the V-shaped groove 3
4a is defined. The inside of this V-shaped groove 34a is filled with a sealing material 35 which may be an epoxy resin. The portion of these LED array chips 25 excluding the light emitting window 25a, the driver IC 26, the lead wires 27, 29, 31, the wiring 28, 30, and the butt portion 34 filled with the sealing material 35 are sealed with an epoxy resin. It is covered with a stopper 36.

It goes without saying that the present invention is not limited to the above-mentioned embodiment and can be applied in various ways. For example, in the above-mentioned embodiment, the alumina substrate 2 and the resin substrate 3 were in partial contact with each other. Alternatively, a predetermined gap may be formed between both substrates in advance, and this gap may be filled with a sealing material.

[Effects of the Invention] As described above, according to the present invention, by airtightly filling the gap between a pair of mutually adjacent substrates with the first sealing material,
Since it is possible to prevent air bubbles from entering the inside of the second sealing material that covers the first sealing material and connection members such as lead wires installed between both substrates, the reliability of the sealing structure is improved. The effect is extremely great because the connection member can be suitably protected.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part of a thermal head showing a first embodiment based on the present invention. FIG. 2 is an enlarged view of the main part of FIG. 1. FIG. 3 is a diagram similar to FIG. 2 showing a second embodiment based on the present invention. FIG. 4 is a diagram similar to FIG. 2 showing a third embodiment based on the present invention. 1...Thermal head 2...Alumina substrate 3...Resin substrate 4...Heat sink 5...
- Butt part 5a...V-shaped groove 6...Driver IC7...Individual electrode 8...Wiring 9.1
0... Lead wire 11... Sealing material 12.
... Sealing material 13... Butt portion 13a... V-shaped groove 14... Sealing material 21... LED array head 22... Heat sink 23... Alumina substrate 24... Resin substrate 25...LED array chip 25a...Window 26...Driver IC2
7, 29, 31... Lead wire 28. 30... Wiring 33... Common electrode 34...
・Butt part 34a...V-shaped groove 35.36...
Sealing material

Claims (4)

[Claims] (1) A substrate sealing structure for protecting connecting members such as lead wires installed between a pair of adjacent substrates, the structure comprising: a first sealing material filling a gap between the two substrates; . A sealing structure for a substrate, comprising: the first sealing material; and a second sealing material covering the connection member. (2) The two substrates are in contact with each other at their end surfaces, and a groove formed by chamfering at least one of the end surfaces is filled with the second sealing material. A sealing structure for a substrate according to claim 1. (3) The two substrates are comprised of a free end substrate on which a resistive heating element film of a thermal head is formed and a proximal wiring substrate. The sealing structure of the substrate described in section. (4) Both substrates are used as LEDs in the LED array head.
3. The substrate sealing structure according to claim 1 or 2, comprising a free-end substrate on which the D array is mounted and a base-end wiring board.