JPH08150751A - Thermal head and its preparation - Google Patents

Abstract

PURPOSE: To make a multi-layered wiring part forming a plurality of common electrode conductive body patterns easily and high density by providing heat generating bodies on individual electrode lead pattern and on the second and the third connection lead patterns. CONSTITUTION: On an insulating base sheet 8, the first common electrode conductive body pattern 9, the first connection pattern 9a connected with one side end part of this pattern 9 and an individual electrode lead pattern 6 are formed. An insulating layer 11 is formed on the pattern 9 so as to expose the first connection lead pattern 9a. In addition, the second common electrode conductive pattern 10 extending from a part on the insulating layer 11 to a part on the insulating base sheet 8, the second connection lead pattern 10b connected with this pattern 10 and the third connection lead pattern 10a connected with the first connection lead pattern 9 are formed. Then, heat generating bodies 7 are formed on the individual electrode lead pattern 6, on the second connection lead pattern 10b and on the third connection lead pattern 10a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head and its manufacturing method.

[0002]

2. Description of the Related Art Conventionally, a thermal head has a structure in which dots of a heating resistor are connected in parallel to one common electrode formed on an insulating substrate. Electric current was supplied from individual drive elements, for example, drive transistors, but with this structure, the number of drive elements required for the thermal head and the area occupied by the drive elements were large, which made it difficult to miniaturize the thermal head.

Therefore, conventionally, each two heating element dots (R0, R1), (R2, R3), (R) as shown in FIG.
4, R5), ..., One drive transistor Tr0, Tr1, Tr2, ... Is provided respectively, and the other ends of the heating element dots R0, R2, R4 are connected to the first common electrode C0.
In addition, it is proposed that the other ends of the heating resistor dots R1, R3, R5, ... Are connected to the second common electrode C1 and the voltage levels of these two common electrodes C0, C1 are switched to perform time-division driving. Has been done. A voltage level is alternately applied to the two common electrodes via a voltage level switching circuit 50 having a power source E, so that the heating element dots connected to the common electrode at the voltage level can be energized. Then, the selection of energization is performed by selecting the drive transistors Tr0, Tr1, Tr2, ...
・ It is performed by selecting ON / OFF of.

With the above structure, the number of the drive transistors is halved to reduce the size, weight and cost. As described above, in the case of a thermal head in which a plurality of common electrodes C0 and C1 are provided and operated by time-division driving, it is necessary to form the common electrodes by multilayer wiring.

3 and 4 show an example of a conventional thermal head having a multilayer wiring structure and its manufacturing process. 3 and 4, first, in FIG.
As shown in FIG. 5, a conductor layer is formed on the insulating substrate 1 by thick film printing or the like over the entire required area, and the first common electrode conductor pattern 2 is formed by photoetching. A comb-teeth-shaped conductor pattern 2a is integrally formed on the first common electrode conductor pattern 2.

Further, an independent lead pattern 2b and an individual lead pattern 6 which are connected to a second common electrode conductor pattern 4 which will be described later are simultaneously formed between the comb tooth-shaped conductor patterns 2a.

Next, as shown in FIG. 3B, the first common electrode conductor pattern 2 and the comb tooth-shaped conductor pattern 2 are formed.
An electrically insulating layer 3 is formed on a. At this time, since the independent lead pattern 2b needs to be exposed from the electrically insulating layer 3, it is formed by thick film printing or the like so that the electrically insulating layer 3 does not overlap the independent lead pattern 2b. Alternatively, an insulator is formed on the first common electrode conductor pattern 2 by vacuum evaporation, and is formed by photoetching leaving only a necessary portion.

After that, a second common electrode conductor pattern 4 is formed on the electrically insulating layer 3 by thick film printing or the like, and the independent lead pattern 2b is connected to the second common electrode conductor pattern 4 and the connecting portion 5. Are connected in common. After the pattern formation, as shown in FIG. 4A, the heating element 7 is formed on the independent lead pattern 2b, the comb-teeth-shaped conductor pattern 2a, and the individual lead pattern 6. The formation of the multilayer wiring portion is completed through the above steps, and in the subsequent steps, a general thermal head such as forming a protective film, mounting a driving transistor, and wire bonding between the driving transistor and an individual lead pattern is manufactured. It

With the above structure, a first conducting circuit composed of the first common electrode conductor pattern 2, the heating element 7 and the individual leads 6, the second common electrode conductor pattern 4,
A second energizing circuit composed of the heating element 7 and the individual leads 6 is formed, and the drive transistor (not shown) wire-bonded to the pad of the individual lead pattern 6 is made conductive to switch the voltage to the heating element dot and supply it. Then, the thermal head can be operated by time-division driving.

[0010]

In the conventional method of manufacturing a thermal head having a multilayer wiring, the insulating layer 3 is formed on the comb-teeth-shaped conductor pattern 2a when the insulating layer 3 is formed. The insulating layer is formed in the shape of a stripe. When this insulating layer is formed by thick film printing, for example, 0.1 mm
It was difficult to form a pattern having the following width, and it was difficult to cope with a high-density pattern. Further, when the insulating layer is formed by vapor deposition or photo etching, dedicated equipment is required, which leads to an increase in cost. In view of the above problems, it is an object of the present invention to provide a manufacturing method capable of easily and densifying a multi-layer wiring portion forming the plurality of common electrode conductor patterns.

[0011]

The thermal head of the present invention comprises a first common electrode conductor pattern (9) formed on an insulating substrate (8) and one end of the first common electrode conductor pattern (9). Connection lead pattern (9a) formed in the portion
An insulating layer (11) formed on the first common electrode conductor pattern (9) so that the first connection lead pattern (9a) is exposed, and an individual electrode formed on the insulating substrate (8). A lead pattern (6) and a second connection lead pattern formed on the first connection lead pattern (9a) and the insulating layer (11) and connected to the first common electrode conductor pattern (9). (10a) and the second common electrode conductor pattern (1) formed on the insulating layer (11).
0), a third connection lead pattern (10b) integrally formed with the second common electrode pattern (10) on the insulating layer (11) and the insulating substrate (8), and the individual electrode lead pattern (10b). 6), the second connection lead pattern (10a) and the third connection lead pattern (10a)
b) A heating element (7) formed above.

In the method for manufacturing a thermal head of the present invention, (a) a first common electrode conductor pattern (9) on an insulating substrate (8) and one end portion of the first common electrode conductor pattern are connected. Forming the first connection lead pattern (9a) and the individual electrode lead pattern (6) (b) The first common electrode conductor pattern so that the first connection lead pattern (9a) is exposed (9) Step of forming insulating layer (11) on (c) Second common electrode conductive pattern (10) extending from the insulating layer (11) to the insulating substrate (8) and the second A second electrode connected to the common electrode conductive pattern (10) of
Forming the connection lead pattern (10b) and the third connection lead pattern (10a) connected to the first connection lead pattern (9a). (D) On the individual electrode lead pattern (6), The second
And the step of forming a heating element (7) on the connection lead pattern (10b) and on the third connection lead pattern (10a).

[0013]

Embodiments of the present invention will be described with reference to FIGS. 1 and 2. 1, (A) of FIG. 1 is a plan view of a main part of a thermal head according to an embodiment of the present invention, (B) of FIG. 1 is a sectional view taken along the line AA ′ of (A) of FIG. 1C is a cross-sectional view taken along the line BB ′ of FIG. 1A, and FIGS. 2 and 3 are explanatory views of a manufacturing process of the thermal head shown in FIG.

First, in the steps shown in FIGS. 2A and 2B, a conductor to be the first common electrode conductor pattern 9, for example, gold is required for thick film printing on the ceramic insulating substrate 8. A film is formed on the entire surface of the region, and patterns 9 and 9a as shown in FIG. 2A are formed by photoetching. A connection lead pattern 9a connected to a second common electrode conductor pattern 10 described later is integrally formed on the first common electrode conductor pattern 9 at the same time.

Next, in a step shown in FIGS. 2C and 2D, an insulating layer 11 is thickly formed on the first common electrode conductor pattern 9 and the connection lead 9a pattern by an insulator such as glass. It is formed by film printing. At this time, the insulating layer 11 is formed in a strip shape so that the connection leads 9a are individually exposed. Since the insulating layer 11 is formed in a simple strip shape without irregularities toward the periphery, pattern formation is easy and can be formed by a screen printing method.

When the insulating substrate 8 has, for example, a glaze layer (not shown) on the surface thereof, the first common electrode conductor pattern 9 is formed and then baked at a high temperature to form a first common electrode in the glaze layer. When the insulating layer 11 is formed by sinking the conductor pattern 9, the connection lead 9a is formed.
It is possible to form the insulating layer 11 on the pattern linearly without waviness at the pattern edge.

After that, in the step shown in FIG. 1, a conductor to be the second common electrode conductor pattern 10, for example, gold is formed on the insulating layer 11 by thick film printing over the entire required area.
Second common electrode conductor pattern 1 by photoetching
Form 0. The second common electrode conductor pattern 10 is roughly classified into two types of sectional structures shown in FIGS.

First, in FIG. 1B showing the AA ′ cross section of FIG. 1A, the second common electrode conductor pattern 1 is formed.
At 0, an independent lead pattern 10a connected to the connection lead 9a pattern formed on the first common electrode conductor pattern 9 is formed. This independent lead pattern 1
Since 0a is completely separated from the other patterns of the second common electrode conductor pattern 10, it can be connected only to the connection lead 9a pattern of the first common electrode conductor pattern 9.

Further, in FIG. 1C showing the BB ′ cross section of FIG. 1A, the first common electrode conductor pattern 9 is formed.
Since the insulating layer 11 is present between the second common electrode conductor pattern 10 and the connection lead pattern 10b,
The first common electrode conductor pattern 9 is electrically separated from the second common electrode conductor pattern 9 and the connection lead pattern 10b. At this time, the first common electrode conductor pattern 9 and the second common electrode conductor pattern 10 are made of the same material, and photoetching of both can be performed under the same condition, so that the multilayer wiring can be easily performed. It is possible.

At the time of photo-etching the second common electrode conductor pattern 10, it is necessary to accurately align the first common electrode conductor pattern 9 with the first common electrode conductor pattern 9. However, the first alignment pattern 12 and the second alignment pattern 1 are aligned with each other.
By providing 3 for each conductor pattern and photomask, alignment can be performed easily and accurately in the photoetching process of the second common electrode conductor pattern 10. Then, after the second common electrode conductor pattern 10 is formed, the process shown in FIG. 1 can be performed by the same operation as the general thermal head as described above.

In the above embodiment, two common electrode conductor patterns are provided, but by repeating the same process, the common electrode conductor patterns can be further multilayered to reduce the number of drive transistors. Is.
In addition, although the conductor layer is formed by thick film printing in this embodiment, a similar structure can be manufactured when the conductor is formed by a thin film process such as vapor deposition or sputtering by using aluminum or the like. it can.

[0022]

According to the structure of the thermal head and the method of manufacturing the same of the present invention, it is not necessary to form a fine pattern having uneven portions in the peripheral direction on the insulating layer separating the plurality of common electrode conductor patterns. The photoetching for forming the common electrode conductor pattern may simply be performed a number of times corresponding to the number of common electrodes, and the multilayer wiring portion of the common electrode can be formed easily with high accuracy.

[Brief description of drawings]

FIG. 1 is a plan view and a cross-sectional view of a main part showing a multilayer wiring pattern of a thermal head of the present invention.

2A and 2B are a plan view and a cross-sectional view showing a step of forming a first common electrode conductor pattern and an insulating layer according to the present invention.

3A and 3B are a plan view and a cross-sectional view showing a conventional process of forming a first common electrode conductor pattern and an insulating layer.

FIG. 4 is a plan view and a cross-sectional view of a main part showing a multilayer wiring pattern of a conventional thermal head.

FIG. 5 is a drive circuit diagram of a thermal head including a plurality of common electrodes.

[Explanation of symbols]

 8 Insulating Substrate 9 First Common Electrode Conductor Pattern 10 Second Common Electrode Conductor Pattern 11 Insulating Layer

Claims (3)

[Claims] 1. A first common electrode conductor pattern (9) formed on an insulating substrate (8), and a first connection lead pattern formed at one end of the first common electrode conductor pattern (9). (9a) and the first connection lead pattern (9a)
To expose the first common electrode conductor pattern (9)
An insulating layer (11) formed on the insulating layer, an individual electrode lead pattern (6) formed on the insulating substrate (8), and the first electrode
On the connection lead pattern (9a) and on the insulating layer (1
1) A second connecting lead pattern (10) formed on the first common electrode conductor pattern (9) and connected thereto.
a), the second common electrode conductor pattern (10) formed on the insulating layer (11), and the second common electrode pattern (10) on the insulating layer (11) and the insulating substrate (8).
Third connection lead pattern (10b) integrally formed with
And a heating element (7) formed on the individual electrode lead pattern (6), the second connection lead pattern (10a) and the third connection lead pattern (10b). head. 2. A method of manufacturing a thermal head, which comprises the following steps. (A) a first common electrode conductor pattern (9) on the insulating substrate (8), a first connection lead pattern (9a) connected to one end of the first common electrode conductor pattern, and Step of forming individual electrode lead pattern (6) (b) Forming an insulating layer (11) on the first common electrode conductor pattern (9) so that the first connection lead pattern (9a) is exposed Step (c) A second common electrode conductive pattern (10) extending from the insulating layer (11) to the insulating substrate (8) and a second common electrode conductive pattern (10) connected to the second common electrode conductive pattern (10). Two
Forming the connection lead pattern (10b) and the third connection lead pattern (10a) connected to the first connection lead pattern (9a). (D) On the individual electrode lead pattern (6), The second
Forming a heating element (7) on the connection lead pattern (10b) and on the third connection lead pattern (10a) 3. The method of manufacturing a thermal head according to claim 2, wherein the first common electrode conductor pattern (9) is connected to one end portion of the first common electrode conductor pattern on the insulating substrate (8). A method of manufacturing a thermal head, characterized in that the formed first connection lead pattern (9a) and the individual electrode lead pattern (6) are simultaneously formed by thick film printing and firing.