JPS61110569A - Thermal head and manufacture thereof - Google Patents

Abstract

PURPOSE:To facilitate manufacture of a thermal head, by a method wherein two substrates provided with respective electrode layers are adhered to each other through a glass layer, the resultant laminate is cut, and a heating resistor is provided on an end face of the cut piece. CONSTITUTION:The substrates 11, 12 provided with respective electrode layers 3, 4 are opposed to each other through the glass layer 5, and are fixed to each other through the glass layer 5. Thus, manufacture and wiring can be easily performed. In addition, by regulating the thickness of the glass layer 5 provided between the selective electrode layer 3 and the common electrode layer 4, it is possible to arbitrarily control the length of the heating resistor 2, and high resolution can be obtained irrespectively of the thicknesses of the substrates 11, 12. Further, since the heating resistor 2 is provided on the end face on which the electrode layers 3, 4 are exposed, the resistor 2 may be provided on only the end face, and there is no bend in the resistor 2, so that the heating resistor 2 with high reliability can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head in which a heating resistor is formed in the direction of an end face of a substrate, and a manufacturing method thereof.

[Conventional technology]

Conventionally, thermal heads such as those disclosed in Japanese Patent Publication No. 40-6040 and Japanese Patent Publication No. 48-38265 are known as thermal heads in which a heating resistor is formed at the end of a substrate. FIG. 7 is a block diagram showing an outline of such a thermal head. The thermal head shown in the figure has a heating resistor 2 formed at the end of a substrate 1, and electrode layers 3.4e laminated on both sides of the substrate 10 so as to partially overlap with the heating resistor 2.

In the thermal head formed in this way, the heat-generating portion of the heat-generating resistor 2 reliably contacts the recording paper, etc.
A thermal head with good thermal efficiency can be obtained. In addition, since the edges of the substrate 1 are easier to flatten than the flat parts, the plural heating resistors 2 can be brought into even contact with the recording paper, etc., and high printing quality can be obtained. I can do it.

[Problem that the invention seeks to solve]

However, in such a thermal head,
Since the electrode layers 3 and 4 are formed on both sides of the substrate 1, there are the following drawbacks.

(a) Since electrode layers must be formed on one side of the substrate 1, alignment of the electrode layers 3 and 4 is not easy.

(b) If a ceramic substrate or other board that is difficult to process through holes is used as the substrate 1, wiring such as lead wiring must be done on a separate board, and the drive IC and other elements must be built in. is difficult.

(c) The size of the printed dot (the length of the heating resistor 2) is determined by the thickness of the substrate 1, so in order to achieve high resolution recording, the substrate 1 must be made thinner. The mechanical strength of the substrate 1 cannot be obtained, and manufacturing becomes difficult.

(d) Since the heating resistor 2 is formed so as to wrap around the edge of the substrate 1, the heating resistor 2 is bent at right angles at the edge of the substrate 1. Therefore, the heating resistor 2 generates heat at 11°C at this edge. 2 may be disconnected.

An object of the present invention is to eliminate the drawbacks of the conventional apparatus as described above, to realize a thermal head that is easy to manufacture, and is suitable for high resolution, and a method for manufacturing the same.

[Means for solving problems]

A thermal head and a method for manufacturing the same of the present invention include two substrates each having an electrode layer formed thereon, which are opposed to each other so that a glass layer is sandwiched between the two substrates, and are bonded together via this glass layer. Two substrates are cut in a straight line so that each electrode layer is exposed on the end face, and a heating resistor is formed on the end face.

(Function) In this way, when two substrates each having an electrode layer formed thereon are arranged to face each other with a glass layer sandwiched therebetween and are bonded to each other via this glass layer, for each substrate, All electrode layers can be formed through a series of manufacturing processes,
It is easy to manufacture, and lead wiring processing such as loss-over required when mounting a driving IC and other elements can be performed simultaneously and within the same substrate. Since the lead wiring pattern is shared between two substrates, there is a high degree of freedom in the lead pattern, which is advantageous for mounting driver elements. In addition, the length of the heating resistor is determined by the thickness of the glass layer formed between the electrode layers, so by adjusting this thickness, the length of the heating resistor can be arbitrarily controlled. A high-resolution thermal head can be realized without affecting strength.

Furthermore, since the end of the substrate is cut and the heating resistor is formed on the exposed end surface of the electrode layer, the heating resistor only needs to be formed on one of the ends, and there is no bending. Therefore, a highly reliable heating resistor can be obtained.

(Embodiment) Hereinafter, an embodiment of the thermal head and its manufacturing method of the present invention will be described with reference to the drawings.In the drawings, the same parts as those in FIG. 7 are designated by the same reference numerals.

An embodiment of the manufacturing process of the thermal head of the present invention is shown in FIGS. 1 to 5. In Figure 1, L has gold (
1. A first substrate on which a first WL electrode layer (hereinafter referred to as selection electrode layer 3) is formed of a conductor such as Au), silver palladium, platinum, or copper; Similarly, 5 is a second substrate on which a second electrode layer 4 (hereinafter referred to as common electrode layer 4) is formed, and 5 is made of high melting point glass or the like, and the selective electrode layer 3 and the common electrode layer 4 are
This is a glass layer that is laminated between the two to form an electrically insulating layer and a thermally resistant layer. As shown in the figure, first a first substrate 1. After printing a glass layer 5 on the soil of the selected electrode layer 3, a second layer is placed on top of this glass layer 5 so as to sandwich it between the common electrode layer 4 side.
Substrate 1. are stacked on top of each other, and the glass layer 5 is fired to form the first and second substrates 1. , L are fixed together. Here, the first substrate 1. The selective electrode layer 3 formed in the second step is formed into a pattern as shown in the figure by etching. However, etching is used to form a fine pattern when obtaining an electrode density of 10 lines/llll11 or more. If the density is relatively low, it is also possible to directly form the electrode pattern as shown in the figure by printing. Note that the thickness of the selective electrode layer 3 and the common electrode layer 4 is generally about 3 to 5 μm.

FIG. 2 shows the state of the glass layer 5 after firing, and in the next step, the first and second substrates 1. , 1. Cut the end of the heating resistor 2 in a straight line along the line a in the figure.
form the end surface to which the material is to be applied.

As a result, the selective electrode layer 3 and the common electrode layer 4 are exposed on the cut end face, as shown in FIG.
Moreover, these electrode layers 3 and 4 are opposed to each other with a glass layer 5 in between. Here, the second substrate 1. is the first substrate 1
．． The first substrate 1. is formed shorter than the first substrate 1.
This is to make it easier to take out the leads from the (selective electrode layer 3).

In the present invention, the heating resistor 2 is formed on the exposed end face of the electrode layer 3.4, but if the surface roughness of the end face after cutting is lower than a predetermined standard, the surface is polished and finished. It is desirable to improve the adhesion of the heating resistor 2 by doing so. FIG. 4 shows an example of a case in which the end surface is polished and chamfered 7[ is applied in order to reduce the contact area with recording paper, etc., and to reduce the total printing pressure.

The end face formed in this way is coated with tantalum nitride (Ta,
A resistive material such as N), nichrome (N+-Cr) is deposited by sputtering or vapor deposition to form the heating resistor 2. The film thickness of the heating resistor 2 in this case is determined in relation to its resistance (fl+, and is approximately 1?
It is about 0.1#Lm.

By the above process, the heat generating resistor 2 is uniformly deposited on the exposed end surfaces of the selection electrode 3 and the common electrode layer 4 and is in electrical continuity with these electrodes. needs to be separated for each selection electrode 3.

FIG. 5 shows a state in which the heating resistor 2 is separated into shapes corresponding to the selection electrodes 3. In the illustrated example, the heating resistor 2 is separated using laser cutting, and 6 is the locus of the laser cutting. The width of the laser cut (the line width of the locus 6) is determined by the spot of the laser beam, and the minimum width can be up to about 30 μm, making it easy to form a high-density heating resistor.

When the heating resistor 2 is divided into 1l11 as described above,
Silicon oxide (SjO,), tantalum pentoxide (Ta, O,) as protection for heating resistor 2 and W14 wear layer
, boron nitride (BN), silicon carbide (SjC), etc., are deposited by sputtering or evaporation. Furthermore, in consideration of thermal conductivity, a wear-resistant metal layer may be applied by split-dip plating after insulating with silicon oxide or the like. In this case, nickel is mainly used for the metal film, and by adding aluminum oxide, boron nitride, diamond, etc. as a dispersant, thermal conductivity and wear resistance can be improved. FIG. 6 is a sectional view showing the state in which this iiJ wear layer 7 is adhered.

Further, as shown in FIGS. 5 and 6, the length of the heating resistor 2 is determined by the thickness of the glass layer 5 interposed between the selection electrode 3 and the common electrode layer 4. By adjusting the film thickness of the heating resistor 5, the length of the heating resistor 2 can be arbitrarily controlled by It11. For example, glass layer 5
As a means of controlling the film thickness of the first and second substrates 1, spherical alumina powder with a constant particle size and shape, cylindrical fiberglass with a constant diameter, etc. are mixed into the glass layer 5. 1. By acting as a spacer between the glass layers 5, the glass layer 5 can be fired while maintaining a constant spacing.

The thermal head of the present invention is formed by the steps described in -1-, but in such a thermal head,
A substrate 1 on which electrode layers 3 and 4 are formed, respectively. , 1. are made to face each other with the glass layer 5 interposed therebetween and are fixed together, which facilitates manufacturing and wiring processing, and also reduces the need for the glass layer 5 interposed between the selection electrode layer 3 and the common electrode fIiA''J4. By adjusting the film thickness, the length of the heating resistor 2 can be arbitrarily controlled.
．． High resolution can be obtained regardless of the thickness etc. In addition, since the heating resistor 2 is formed on the exposed end surface of the electrode layer 3.4, the heating resistor 2 only needs to be attached to the end surface, and since there is no bending, the heating resistor 2 is highly reliable. body 2 can be formed. Furthermore, substrate 1. , 1. The step of sputtering or vapor depositing the heating resistor 2 on the end face of the substrate 1. , 1. The substrate 1. , 1. A large number of them can be installed in sputtering equipment, etc., making mass production possible.

In addition, in the above description, the substrates 13°1,
Although the first electrode layer 3 and the second electrode layer 4 are formed directly on the surface of the substrate 1. , 1. Depending on the surface smoothness of the substrate 1. , 1. A glass layer may be provided between the electrode layer 3.4 and the electrode layer 3.4 to smooth the base of the electrode layer 3.4. Furthermore, although laser cutting has been exemplified as a means for separating the heating resistor 2, there are other means for separating the heating resistor 2, such as etching by photolithography, mechanical cutting with a blade, and sandblasting. , which can be used as needed. Furthermore, H formed on the heating resistor 2
The wear layer 7 is not limited to a metal film, and a glass layer can also be used. Also, in Figure 6 of the song,
By changing the length Q of the glass layer 5 interposed between the electrode layers 3.4, the thermal conductivity of this portion changes, so the thermal response characteristics of the head can be changed as desired.

〔Effect of the invention〕

As explained above, the thermal head of the present invention and its! ! In the manufacturing method, two substrates each having an electrode layer formed thereon are placed facing each other with a glass layer serving as an electrical insulating layer and a thermal resistance layer sandwiched between them, and are fixed together via this glass layer. Each layer is cut in a straight line and a heating resistor is formed on the exposed end face of each electrode layer, making it possible to perform lead wiring such as crossovers, making the head including the driver more compact. Reducing the number of parts and connection points through common use, and lower prices! n1 of l'l+1 can be realized. Further, it is possible to easily control the length of the heating resistor, to easily manufacture the thermal head, and to realize a thermal head suitable for high resolution and a method for manufacturing the same.

[Brief explanation of the drawing]

1 to 6 are block diagrams showing embodiments of a thermal head and a method for manufacturing the same according to the present invention, and FIG. 7 is a block diagram showing an example of a conventional thermal head. 1.1. ．． 1. ...Substrate, 2...Heating resistor, 3.
...Selection electrode layer, 4...Common electrode layer, 5...Glass layer, 6...Laser cut, 7...In4 wear layer. Figure 1 Figure 3 Figure 4 Figure 2 Figure 5 Figure 6

Claims (2)

[Claims] (1) A glass layer serving as an electrical insulating layer and a heat resistance layer, and a first and second glass layer each having an electrode layer formed on one surface thereof and facing each other so as to sandwich the glass layer between the electrode layers. A thermal head comprising: a substrate; and a heating resistor formed on an end face where the plurality of electrode layers are exposed. (2) a step of facing two substrates each having an electrode layer formed on one side with a glass layer interposed therebetween and fixing them together;
A method for manufacturing a thermal head, comprising the steps of: cutting each layer including a substrate into a straight line at its end; and forming a heat generating resistor on an end surface where a plurality of electrode layers are exposed by the cutting step.