JP3362234B2 - Electronic component and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component and a method for manufacturing the same, more specifically, a thermal print head used in a printer, a plotter, a facsimile, and the like.
The present invention relates to an electronic component such as an image sensor used in an ED head, a reading unit of a facsimile, or other optical reading device, and a manufacturing method thereof.

For example, a conventional general structure of a so-called line type thermal print head having a long print width is as follows. That is, a row of heating elements arranged in a row is formed on an insulating head substrate having a rectangular plate shape, and a plurality of drive ICs for individually driving the elements of the row of heating elements are mounted. The substrate is attached on a supporting substrate made of aluminum or the like and having a heat dissipation function. Further, on the head substrate, an individual electrode pattern which is electrically connected to the output pad of the driving IC and reaches each heating element, and the heating element array which is commonly conducted to each heating element and supplies electric power to the heating element row. In addition to the common electrode patterns that are extended in parallel, a signal wiring pattern that controls signal supply to each drive IC is formed. Each wiring pattern is formed by forming a thin glass glaze layer on an insulating substrate, forming a conductive metal coating film such as gold, and performing etching treatment on the conductive metal coating film. And the common electrode pattern is
In order to increase the current capacity, it is formed by printing and firing a silver paste or a silver / palladium paste so as to overlap a wiring pattern made of a conductive metal film.

By the way, various structural modifications have been made in order to solve various problems in the general line type thermal print head as described above. For example, when the print width is long, the voltage drop in the central portion of the common electrode pattern becomes remarkable, which deteriorates the print quality. However, in order to solve such a problem, it is proposed in JP-A-4-52149. In a thermal print head, a base substrate is interposed between a head substrate and a supporting substrate, an auxiliary common electrode is formed on the base substrate, and the common electrode on the base substrate and the head substrate are formed. The original common electrode pattern is connected by a conductive member. Then, since the substantial current capacity of the common electrode pattern is doubled by the auxiliary common electrode, the problem of the voltage drop described above is solved.

However, the above-mentioned Japanese Patent Laid-Open No. 4-52149.
In the configuration proposed in the publication, since the base substrate has to form the common electrode on the upper surface while overlapping under the head substrate, its area becomes larger than the head substrate, and the entire thermal print head as a whole is There is a problem of increasing the size.

Further, in the thermal print head having the above-mentioned general structure, since the drive IC is also mounted on the head substrate, a relatively complicated process of forming the glass glaze layer and then patterning the wiring is performed. The head substrate manufactured in the past becomes large in size, the number of head substrates taken from the manufacturing substrate decreases, and the cost of the head substrate increases accordingly, but in order to solve such a problem, JP-A-4-338556. In the thermal print head proposed in, a heating element array, an individual electrode pattern, and a common electrode pattern are formed on a head substrate, a drive IC is mounted on a base substrate on which the head substrate is mounted, and a signal wiring pattern is formed. Is formed. In this case, the output pad of the drive IC on the base substrate and the individual wiring pattern on the head substrate are connected by wire bonding or the like.

In the structure proposed in the above-mentioned Japanese Patent Laid-Open No. 4-338556, it is not necessary to mount the drive IC on the head substrate, so that the planar shape of the head substrate can be made smaller, and the manufacturing substrate can be made smaller. The number from
The manufacturing cost of the head substrate itself can be reduced.

However, it takes a considerable number of man-hours to correct the wire displacement between the drive IC mounted on the base substrate and the individual wiring pattern on the head substrate while compensating for the positional deviation. In addition, there is a problem that the manufacturing cost of the entire thermal print head cannot be reduced so much.

The present invention has been devised under the circumstances as described above. For example, in a thermal print head, a circuit of a circuit is formed under a substrate (element substrate) on which a heating element array is formed. It is an object of the present invention to make it possible to significantly reduce the planar shape of the whole and to easily manufacture and assemble it when the base boards (circuit boards), which are partially formed, are laminated. I am trying.

[0009]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention takes the following technical means.

An electronic component according to claim 1 of the present application is an electronic component including a circuit board and an element substrate arranged so as to be laminated on the circuit board, and the element substrate has a surface thereof. A plurality of driven elements arranged along one side edge of the substrate, and a common electrode extending in a strip shape on one side of the array of driven elements so as to be electrically connected to each driven element in common. A pattern, an individual electrode pattern on the other side of the array of driven elements that individually conducts to each driven element, and a drive I that controls turning on / off of each individual electrode pattern
C and a signal wiring pattern for supplying a signal to the driving IC on the other side of the driving IC, and a conductive path for the common electrode pattern and the signal wiring pattern on the back surface thereof. The circuit board has a plurality of connection patterns corresponding to each land pattern on the back surface side of the element substrate, a wiring pattern that is conductive to the connection pattern, and The circuit board is provided with a plurality of terminals that are electrically connected to the wiring pattern and that are disposed on the other side of the circuit board and that are disposed on the other side of the circuit board. Each of the connection patterns of the substrate is characterized in that they are connected to each other by a conductive connection means.

The element substrate and the circuit board can be connected in a laminated manner by connecting the land pattern and the connecting pattern to each other by a conductive connecting means (claim 2).

The conductive path may be a through hole, a VIA hole, and / or a conductive means formed on the side surface of the element substrate (claim 3).

The conductive connecting means may be solder, a conductive adhesive, or a conductive paste applied and fired (claim 4).

If the driven element is a heating element, the electronic component has a structure as a thermal print head (claim 5).

In this case, both the element board and the circuit board are made of board materials having a similar linear expansion coefficient (claim 6), and the clearance between the circuit board and the element board is: It is desirable to interpose an insulating member having a good heat transfer property such as a silicon compound (claims 7 and 8).

According to a ninth aspect of the present invention, there is provided a method for manufacturing an electronic component according to the first aspect, wherein a plurality of driven elements are arranged on a surface of the substrate along one side edge of the substrate.
A common electrode pattern extending in a strip shape on one side of the array of driven elements so as to be electrically connected to each driven element, and individually connected to each driven element on the other side of the array of driven elements. An individual electrode pattern, a drive IC for controlling ON / OFF of each individual electrode pattern, and a signal wiring pattern for supplying a signal to the drive IC on the other side of the drive IC are provided on the back surface thereof An element substrate having a plurality of land patterns electrically connected to the common electrode pattern and the signal wiring pattern through a conductive path, and a plurality of connection patterns corresponding to the land patterns on the back surface side of the element substrate, A wiring pattern that conducts to the connection pattern, and to the other side of this circuit board that conducts to this wiring pattern and to the other side of the element substrate And a circuit board having a plurality of terminals arranged in protruding portions, by connecting the mutually electrically conductive connection means between the land pattern and the connecting patterns, characterized in that connected in layers.

In this method, cream solder is printed and applied on each connection pattern of the circuit board, and then the element board is overlaid on the circuit board so that the land pattern is overlaid on the connection pattern. After being introduced into the heating furnace, the circuit board and the element board can be connected in a laminated manner by cooling.
0).

The electronic component according to claim 1 of the present application has a double substrate structure including an element substrate on which a driven element is formed and a circuit board. Therefore, most of the wiring patterns to be electrically connected to the driven element can be formed on the circuit board, and the planar shape of the element board can be reduced. Further, the electrical connection between the wiring pattern on the element substrate and the wiring pattern on the circuit board is established by the conductive path extending in the thickness direction of the element substrate, the land pattern, and the conductive connecting means. There is no problem even if a wiring pattern is formed on the part hidden by the board,
As a result, it becomes unnecessary to make the planar shape of the circuit board larger than that of the element substrate. From the above, the electronic component of the present invention can be miniaturized in its planar shape as a whole.

Further, as described in claims 2 and 9, in the electronic component and the method for manufacturing the same of the present invention, a conductive material for connecting the wiring pattern on the circuit board and the land pattern on the back surface of the element substrate. The connecting means has both the function of achieving electrical conduction between the circuit board and the element substrate and the function of connecting the circuit board and the element substrate on the stacked layers. Therefore, the structure is simplified, and no special means for connecting the two substrates is required, and the number of assembling steps is further simplified.

In particular, if the connection between the land pattern on the back surface of the element substrate and the wiring pattern on the circuit board is achieved by the so-called reflow soldering method as in the tenth aspect, all the electrical connections can be made in a single process. The connection of parts is completed and the manufacturing process is significantly simplified.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the drawings.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below.
A specific description will be given with reference to the drawings. The embodiment shown in the drawing is an example in which the present invention is applied to the line type thermal print head 1.

As shown in FIGS. 1 and 2, the thermal print head 1 of this example has a double substrate structure including an upper element substrate 2 and a lower circuit substrate 3. Element substrate 2
Is placed on an insulating material substrate such as alumina ceramics via a heat storage glass glaze tank (not shown) and is provided on one side edge 2a of the substrate.
A heating element row 4 as a driven element extending linearly along the common electrode pattern extending in a strip shape in a region between the example heating element and one side edge 2a of the substrate so as to be commonly conducted to each heating element. 5, the other side 2 of the substrate with the heating element row 4 interposed therebetween
In the direction b, a fine individual electrode pattern 6 which is individually conducted to each heating element is formed, and a plurality of drive ICs 7 for controlling the on / off of the individual electrode pattern 6 are mounted and are generally formed.

A signal wiring pattern 8 for supplying a signal to the driving IC 7 is formed in a region on the element substrate 2 which is on the other side 2b of the substrate with respect to the driving IC 7. For each wiring pattern, after forming a conductive metal coating such as gold on the substrate material,
It is formed by performing etching processing or the like. The common electrode pattern 5 is formed by printing and firing a silver paste or a silver / palladium paste on the conductive metal film.

However, in the case of the present invention, the element substrate 2 is used.
The common electrode pattern 5 formed above does not need to be thickened or thickened in order to secure the necessary current capacity by itself, and may have a narrow width.

Through holes (or VIA holes) 10 for electrically connecting the common electrode pattern 5 and the land pattern 9 formed on the back surface are formed in the element substrate 2 at a plurality of equal intervals. Has been done. The through hole 10 can be easily formed by a known method in which the conductive material paste is applied to the inner wall of the through hole formed in the substrate by suction and then baked. Further, the land pattern 9 on the back surface of the element substrate 2 can be easily formed by a thick film printing method using a conductive material paste.

Further, in this embodiment, the other side 2 of the substrate
Also for the signal wiring pattern 8 arranged in the direction b, the back surface land pattern 9 is provided via the through holes 10 at a plurality of locations.
It is conducted to. The surface of the element substrate 2 is covered with the glass protective layer 11.

On the other hand, the circuit board 3 is made of an insulating material such as alumina ceramic as in the case of the element board 2, and its upper surface is made to correspond to the common electrode pattern 5 on the element board 2 in plan view. , Auxiliary common electrode pattern 1
2 is formed by, for example, a thick film printing method using a conductive material paste. In the case of the circuit board 3, both ends 12a and 12a of the auxiliary common electrode pattern 12 are
It extends to the terminal 13 on the other side of the substrate. In addition, a plurality of wiring patterns 14 connected to the terminals 13 on the other side of the circuit board are provided so as to planarly correspond to the through holes 10 or the land patterns 9 formed on the signal wiring pattern 8 on the element substrate 2. Is also formed by the thick film printing method. In addition, all terminals 13
Are arranged side by side in the protruding portion of the circuit board 3 to the other side of the element substrate 2.

The circuit board 3 and the element substrate 2 are formed by, for example, soldering or a conductive adhesive between each land pattern 9 on the back surface of the element substrate 2 and the corresponding wiring patterns 12, 14 on the circuit board 3. Alternatively, they are connected to each other in a laminated manner by connecting them by the conductive connecting means 15 such as coating and firing of a conductive material paste. For example, in order to connect the two boards 2 and 3 by the solder reflow method, first, cream solder is applied to a predetermined portion of the wiring patterns 12 and 14 on the circuit board 3 by printing or the like, and then the circuit board 3 is formed. A well-known method is adopted in which the element substrate 2 is mounted while being positioned thereon, and this laminate is introduced into a heating furnace and cooled. In this way, the electrical connection parts are collectively and reliably formed, and the electrical reliability of the thermal print head is improved.

In the present embodiment, the two substrates 2 and 3 are connected by the conductive connecting means 15 at a plurality of locations in relation to the common electrode pattern 5 on the one side 2a of the substrate, and the signal is provided on the other side 2b of the substrate. Since the boards 2 and 3 are connected by the conductive connecting means 15 at a plurality of locations in relation to the wiring pattern 8, the conductive connection such as the solder can be made without any other means for mechanically connecting the boards. By using only the means, both substrates can be integrated in a laminated state, and the number of manufacturing steps and the number of parts can be reduced.

In the above structure, the signal input from the signal terminal 13 of the circuit board 3 is the wiring pattern 14, the conductive connecting means 15, the land pattern 9, the through hole 1.
0, it is introduced into each drive IC 7 through the signal wiring pattern 8, and each drive IC 7 controls the on / off of the individual electrode pattern 6 according to the signal. The heating elements that are electrically connected to the individual signal pattern 6 in the ON state receive the current supplied from the common electrode pattern 5 and individually generate heat. A current is supplied to the common electrode pattern 5 through the auxiliary common electrode pattern 12, the conductive connecting means 15, the land pattern 9 of the element substrate 2, and the through hole 10 on the circuit board 3.

Therefore, even if the common electrode pattern 5 on the element substrate 2 is thin and thin and its current capacity is small, the auxiliary common electrode pattern 1 on the circuit board 3 is small.
Since a sufficient current flows from 2 to the through hole 10, the voltage drop at the central portion of the common electrode pattern 5 can be minimized, and the deterioration of the print quality due to this voltage drop can be conveniently avoided. it can.

As is apparent from FIGS. 1 and 2, the wiring necessary for forming the thermal print head 1 is formed separately on the element substrate 2 and the circuit substrate 3, and the wiring is formed on the element substrate 2. The common electrode pattern 5 may be thin, and the auxiliary common electrode pattern 1 formed on the circuit board 3
2 may be formed so as to overlap with the common electrode pattern 5 of the element substrate 2 in a plane, and therefore the circuit board 3 need not be formed larger than the element substrate 2 than necessary. In this embodiment, a thermal print head having a significantly reduced dimension in the substrate width direction is achieved.

Further, as shown in FIG. 2, if an insulating member 16 having good thermal conductivity is provided in the clearance between the circuit board 3 and the element substrate 2, the circuit board 3 and the element board 2 are separated from the circuit board. This is advantageous because heat dissipation can be further promoted. An example of such an insulating member is a silicon compound.

Further, it is preferable that both the element substrate 2 and the circuit board 3 are formed by using a material having a small linear expansion coefficient such as alumina ceramic, and the thermal print head is warped due to the bimetal effect, and the conductivity such as solder is caused. It is desirable to avoid the concentration of thermal stress on the connecting portion by the connecting means 15. As another substrate constituent material satisfying such a condition, as shown in FIG. 3, a metal plate material having a low linear expansion coefficient such as 42 alloy is used as the core material 17, and the insulating resin film 1 is formed on the surface thereof.
8 is formed, and a wiring pattern 19 made of a conductive metal film such as copper or gold is formed thereon by a patterning method such as etching.

FIG. 4 shows a thermal print head 1 having the same basic structure as that of the above-described embodiment, including an element substrate 2
Another method of electrically connecting the upper common electrode pattern 5 and the back surface land pattern 9 is shown. That is, in this example, the conductive film 10a is formed on one side surface of the element substrate 2 instead of the method using the through hole 10 as in the above-described embodiment.
Is formed and is electrically connected to the common electrode pattern 5 on the front surface side and the land pattern 9 on the back surface side. The conductive coating 10a can be easily formed by applying and firing a silver paste or a silver / palladium paste. This conductive coating 10
The a may be formed on one side surface of the element substrate 2 over the entire length of the substrate, or may be formed discretely here and there. In FIG. 4, reference numeral 20 indicates the conductive film 10a.
Is an insulating resin protective layer for covering.

It is obvious, of course, that this example can be expected to have the same operational effects as those of the above-mentioned embodiment, without needing to explain it again.

Of course, the scope of the present invention is not limited to the above embodiments. Although the embodiment shown in the figure has a double substrate structure composed of an element substrate and a circuit board, when a thermal print head is configured, the head having the double substrate structure is made of aluminum or the like in order to improve heat dissipation performance. It is of course within the scope of the present invention to attach and mount it on the resulting heat dissipation plate.

The above-described embodiment is an example in which the present invention is applied to the thermal print head in which the driven element to be formed on the element substrate 2 is the heating element array 4, but an LED array chip is used as the driven element. The dual substrate structure of the present invention can be applied to LED print heads arranged in rows and image sensors formed by arranging image sensor array chips as driven elements in rows.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention.

2 is a cross-sectional view of the embodiment shown in FIG.

FIG. 3 is a cross-sectional view showing another example of forming a substrate.

FIG. 4 is a cross section of another embodiment of the present invention.

[Explanation of symbols]

1 Thermal print head 2 element substrate 3 circuit board 4 heating element array 5 Common wiring pattern 6 Individual electrode pattern 9 land patterns 10 through holes 12 Auxiliary common electrode pattern 14 wiring pattern 15 Conductive connection means

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/335 H01L 23/12

Claims (10)

(57) [Claims] 1. A circuit board and a laminate on the circuit board.
Is an electronic component that has an element substrate arranged in
Te, the element substrate, on the surface, the edge of one side of the substrate
A plurality of driven elements arranged along
One side of the array of driven elements so that
Common electrode pattern extending in strips and driven elements
In the other side of the arrangement, the elements are individually conducted to each driven element.
Individual electrode patterns that can be turned on and off
Controlling the driving IC and further side to this driving IC
Wiring pattern for supplying a signal to the drive IC in
And the common electric
Conductive traces for the pole pattern and the signal wiring pattern
It is equipped with multiple land patterns that conduct through the paths.
The above-mentioned circuit board consists of land patterns on the back side of the element board.
Multiple connection patterns corresponding to
To a wiring pattern that is electrically connected to the
The other side of the element board on the other side of the circuit board.
With a plurality of terminals arranged on the protruding portion toward
According to another aspect of the present invention, there is provided an electronic component, wherein the back surface side land patterns of the element substrate and the connection patterns of the circuit board are connected to each other by conductive connecting means. Wherein the above element substrate and the circuit board, by connecting the mutually electrically conductive connection means between the land pattern and the connecting patterns are connected in layers, according to claim 1 Electronic components. 3. The conductive path is a through hole, a VIA.
The electronic component according to claim 1, which is a conductive means formed on the side surface of the hole or / and the element substrate. Wherein said conductive connection means is a solder, conductive adhesive, or a conductive paste obtained by coating and firing, electronic component according to any one of claims 1 to 3. 5. The driven element is a heating element,
The electronic component according to any one of claims 1 to 4. 6. The element substrate and the circuit board are both
It is formed by using a substrate material having a linear expansion coefficient of the same degree,
The electronic component according to claim 5. 7. A spacer between the circuit board and the element board.
An insulating member having good heat conductivity is interposed in the gap,
The electronic component according to claim 5. 8. The insulating member is a silicone compound.
The electronic component according to claim 7, which is 9. The surface of the substrate along one side edge thereof.
Driven elements arranged in a plurality, common to each driven element
To one side of the array of driven elements so that
Common electrode pattern that extends in a strip shape, array of driven elements
Individually connected to each driven element on the other side
Driving to control ON / OFF of the electrode pattern and each individual electrode pattern
Moving IC and further to the side of this driving IC
Signal wiring pattern for supplying a signal to the drive IC
And the common electrode pad on the back side.
A conductive path for the turn and the signal wiring pattern
An element substrate having a plurality of land patterns that are electrically connected via the
The connection pattern and the wiring pattern that conducts to this connection pattern.
Turn and conduct to this wiring pattern, this circuit
Protrusion to the other side of the element board on the other side of the board
A circuit board having a plurality of terminals arranged in the bent portion is used to guide the land pattern and the connection pattern to each other.
By connecting with an electrical connection means
A method for manufacturing an electronic component, which comprises: 10. On each connection pattern of the circuit board
After printing and applying cream solder, the above connection pattern
The land pattern on top of the circuit board
After stacking the above element substrate on top of it and introducing it into the heating furnace, cool it down.
The circuit board and the element board by stacking
The method according to claim 9, wherein the methods are connected in layers .