JPH0635187B2 - Method of manufacturing thermal head - Google Patents

Description

The present invention relates to a method for manufacturing a thermal head, and more particularly to a thermal head having a heating resistor array protruding in a convex shape from the surface of an insulating substrate. It relates to a manufacturing method.

(Prior Art) Generally, in a thermal head, in order to improve the adhesion between the heating resistor array and the recording medium such as thermal paper and thermal transfer ribbon, the heating resistor array is convex from the surface of the insulating substrate. The one that is projected to the above is widely put into practical use.

Usually, such a thermal head is manufactured as follows.

First, a line-shaped glaze layer having a convex cross-section made of glaze glass is formed by screen printing on an insulating substrate made of alumina ceramics or the like.

After that, a heating resistor film is formed on the surface of the thermal head substrate on which the glaze layer is formed by a sputtering method or a vacuum evaporation method, and a constant amount near the top of the glaze layer is formed by a photoetching method using a desired mask. A heating resistor array including a large number of heating resistor elements is patterned in the region.

Then, a metal thin film is formed on the surface of the thermal head substrate on which the heating resistor array is formed by a sputtering method or a vacuum deposition method, and a lead wiring is patterned by the same photoetching method as above.

By the way, in such a thermal head, it is desirable that the heating resistor rows are accurately arranged in a certain area near the top of the glaze layer in order to ensure close contact with the recording medium. It is necessary to accurately align the insulating substrate with reference to the end face of the insulating substrate.

(Problems to be solved by the invention) However, when the glaze layer is formed by screen printing, it is unavoidable that a deviation of about ± 0.2 μm from the normal position occurs, and the heat generation on the glaze layer is unavoidable. Even when the pattern of the resistor array is formed by the photo-etching method, there is a possibility that a positional deviation of about ± 0.25 to ± 0.3 μm or more may occur.

Therefore, even if the alignment before forming each pattern is performed with reference to the end face of the insulating substrate, it is difficult to accurately arrange the heating resistor array in a certain region near the top of the glaze layer. .

In view of such a difficulty, recently, the glaze layer is formed on an insulating substrate, and at the same time, an alignment pattern is formed, and a photomask for etching is provided with another alignment pattern corresponding to the alignment pattern. Attempts have been made to improve the accuracy by forming a working pattern and matching these patterns at the time of alignment.

However, even if such a method is used, the shape of the alignment pattern is deformed during pattern baking after screen printing, and as a result, when the alignment patterns are matched, about ± 50 to ± 100 μm. There is a high possibility that the position shift of will occur. Further, since all such alignment work is performed by the operator's eyes, there is a problem that mass productivity is poor.

The present invention has been made in response to such conventional circumstances,
Provided is a method of manufacturing a thermal head capable of forming a heating resistor element array more accurately at a predetermined position on a glaze layer and mass-producing a product having good adhesion to a recording medium. Is intended.

[Structure of the Invention] (Means for Solving Problems) In order to achieve such an object, the present invention forms a line-shaped glaze layer having a convex cross-section on an insulating substrate, and forms the line on the glaze layer. In manufacturing a thermal head having a heat-generating low-antibody element formed at a predetermined position, the surface of the glaze layer is irradiated with light perpendicular to the surface of the insulating substrate, and the surface of the glaze layer is irradiated with light. Positioning for forming the heating resistor element array at a predetermined position on the glaze layer is performed based on the intensity or intensity distribution of the reflected light.

(Operation) The method of manufacturing the thermal head of the present invention is based on the intensity or intensity distribution of the light reflected from the surface of the glaze layer by irradiating the surface of the glaze layer with light perpendicular to the surface of the insulating substrate. Since the alignment is performed to form the heating resistor element array at a predetermined position on the glaze layer, it is possible to more accurately form the heating resistor element array at a predetermined position on the glaze layer. Therefore, it is possible to mass-produce a product having good adhesion to the recording medium.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

1 and 2 are views showing a method of manufacturing a thermal head according to an embodiment of the present invention.

As shown in these figures, in the manufacturing method of this embodiment,
First, at a predetermined position on an insulating substrate 1 made of, for example, alumina ceramics, a glaze layer 2 made of glaze glass having a height of several tens of μm and a width of about 2 mm and having a convex section is formed in a line shape by screen printing. (Fig. 2-a).

After that, the heating resistor film 3 is formed on the insulating substrate 1 on which the glaze layer 2 is formed by a sputtering method or a vacuum evaporation method (FIG. 2B).

Next, a photosensitive resist resin is applied on this and dried to form a resist layer 4 (FIG. 2C).

Then, as shown in FIG. 1, the end face of the insulating substrate 1 is placed on the movable stage 6 for aligning the thermal head substrate A on which the resist layer 4 is formed with the photomask 5 and the side face of the positioning pin 7. Install it in the state of abutting against.

After that, a light S _{1 from} a light source (not shown) that is a safe color to the photosensitive resist resin and is perpendicular to the surface of the insulating substrate ₁
The resist layer surface 4 corresponding to the glaze layer 2 surface
Irradiate a. In this case, the light S ₁ is applied to a range wider than the width of the glaze layer 2.

By the way, as shown in FIG. 3, since the surface of the glaze layer 2 has a substantially arc shape, the reflection angle of the light S ₁ incident on each point on the resist layer surface 4a is equal to that of the incident point. The position spreads from the apex to both sides.
From this, the intensity distribution B ₁ of the light S ₂ reflected on the resist layer surface 4a is reflected on the virtual plane C at the position corresponding to the apex of the glaze layer 2 as shown in FIG. It will be the peak of.

That is, in this embodiment, the reflected light S ₂ from the portion of the resist layer surface 4a corresponding to the surface of the glaze layer 2 is directed above the thermal head substrate A by 45 degrees with respect to the short side direction surface of the thermal head substrate A. The photodetector 9 detects the light received through the semi-transparent mirror 8 that is inclined with respect to the photodetector 9 to obtain the intensity distribution B ₁ of the reflected light as described above.

Now, the vertex of the glaze layer 2 of the thermal head substrate A placed at a normal position and the position of the photomask 5 corresponding to this are connected to form a line R ₁ , and the reflected light S ₂ from the vertex is A line R ₂ is formed by connecting the position where the light reaches the semi-transparent mirror 8 and the position where the light S ₂ reflected from this position reaches the photodetector 9.

Under these conditions, when the position of the apex of the glaze layer 2 of the thermal head substrate A installed on the movable stage 6 is displaced from the line R ₁ by the distance d ₁ as shown by the broken line in the figure, Light S reflected from the vertex of the glaze layer 2
₂ reaches a position on the photodetector 9 which is displaced from the line R ₂ by a distance d ₂ . Therefore, the position of the peak of the light intensity distribution B ₂ due to such reflected light S ₂ is also the line R.
_The position is shifted from ₂ by a distance d ₂ .

Then, the movable stage 6 is horizontally moved in the direction of arrow E in the drawing so that the peak position of the light intensity distribution B ₂ obtained by the photodetector 9 overlaps the line R ₂ , and the apex of the glaze layer 2 becomes normal. Install it in a proper position.

After performing the alignment as described above, a photomask 5 is placed on the insulating substrate 1 on which the resist layer 4 is formed, and a heating resistor is provided in a certain area near the top of the glaze layer 2 by a normal photoetching method. The rows 10 are patterned (Fig. 2-d).

After that, a metal thin film 11 is formed on the entire surface of the insulating substrate 1 by a sputtering method or a vacuum evaporation method (FIG. 2E), a resist layer 4 is formed, and then a lead wiring is formed by a photoetching method using a desired mask. 12 is patterned (FIG. 2-f).

Thus, according to the method of manufacturing the thermal head of this embodiment, the glaze layer 2 can be aligned on the basis of the peak position of the intensity distribution B ₁ of the reflected light from the glaze layer 2, so that the heating resistor is formed. The rows 10 can be more accurately formed in place on the glaze layer 2. Further, such alignment can be achieved only by setting the positions of the photomask 5, the movable stage 6, the semi-transparent mirror 8 and the photodetector 9 in advance, so that mass productivity can be improved and labor can be reduced. Become.

In this embodiment, the case where the reflected light is directly received by the photodetector 9 has been described, but an enlarged or reduced image may be formed through the lens system. Further, although the semi-transparent mirror 8 is arranged between the photomask 5 and the movable stage 6, it may be arranged on the photomask 5 as long as the reflected light reaches it.

[Effects of the Invention] According to the method of manufacturing a thermal head of the present invention, the heating resistor element array can be formed more accurately at a predetermined position on the glaze layer and has good adhesion to the recording medium. The product can be mass-produced.

[Brief description of drawings]

FIG. 1 is a side view for explaining a method of manufacturing a thermal head according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a thermal head substrate for each step, and FIG. 3 is a glaze layer surface. FIG. 4 is a side view showing a reflection state of light in a corresponding portion, and FIG. 4 is a view showing a light intensity distribution on a predetermined plane by the reflected light. 1 ... Insulating substrate 2 ... Glaze layer 5 ... Photomask 6 ... Movable stage 8 ... Semi-transparent mirror 9 ... Photodetector 10 ... Heating resistor array

Claims (1)

[Claims] 1. A glaze layer having a convex cross-section is formed in a line on an insulating substrate and a heating resistor element array is formed at a predetermined position on the glaze layer. The surface portion of the layer is irradiated with light perpendicular to the surface of the insulating substrate, and the heating resistor element array is arranged on the glaze layer based on the intensity or intensity distribution of the reflected light from the surface portion of the glaze layer. A method of manufacturing a thermal head, which comprises performing alignment for forming at a predetermined position.