JPH0744163B2 - Substrate for thermal head and electronic component including the same - Google Patents

Description

The present invention relates to a substrate for a thermal head.

(B) Conventional Technology An electronic component such as a thermal head uses a ceramic substrate. In recent years, as the substrate size of the thermal head has been reduced, as shown in FIG. 5, many thermal head substrates have been taken from one large substrate 11. Since the outer dimensions of the substrate 11 are uniform, when a large number of thermal head substrates are to be taken, a discard pattern 15 for adjusting the dimensions is often provided.

A scribe line 12 for facilitating the division is formed on the substrate 11, and the substrate 11 is divided by the scribe line 12 into a pattern 14 of a thermal head substrate and a discard pattern 15. .

The scribe line 12 is formed by laser processing. FIG. 6 is an enlarged view of the scribe line 12, in which the laser beam B is irradiated once at a predetermined pitch to form holes p in a row. The depth d of the hole p is the substrate 11
The thickness t is about 1/3.

(C) Problems to be Solved by the Invention In the substrate 11 described above, the width of the discard pattern 15 is small (2
.About.5 mm), it is difficult to divide the discard pattern 15, and a division defect such as a large crack angle .theta. (See FIG. 4) easily occurs.

Therefore, it is conceivable to deepen the hole p of the scribe line 12. However, if the hole p has a depth of 1/3 or more of the substrate thickness t, the beam diameter becomes large, and microcracks are likely to occur on the substrate 11.

The present invention has been made in view of the above, and an object thereof is to provide a substrate for a thermal head that facilitates division of a discard pattern without causing microcracks.

(D) Means and Actions for Solving the Problem In order to solve the above problem, the thermal head substrate of the present invention forms a scribe line by laser treatment,
In a roughly rectangular substrate divided into each pattern,
The scribe line between the patterns is formed by performing the laser processing once, and the scribe line that defines the discarded pattern on the edge side of the substrate is formed by performing the laser processing twice.

In the thermal head substrate of the present invention, the scribe line that defines the discard pattern on the substrate edge side is irradiated with the laser beam twice to form a hole, so that the hole should be deepened without increasing the beam diameter. You can Therefore, it becomes easy to divide the discard pattern, and it is possible to reduce the occurrence rate of division defects.

(E) Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 2 is a plan view of the electronic component substrate (thermal head substrate) 1 of the embodiment. The electronic component substrate 1 is made of, for example, ceramic, and has scribe lines 2 and 3
Thus, it is divided into a pattern 4 and a discard pattern 5 used as a substrate of an electronic component.

The scribe line 2 divides the patterns 4 from each other, and is formed by one laser treatment as in the conventional case (see FIG. 6). On the other hand, scribe line 3
Divides the pattern 4 and the discard pattern 5,
Laser processing is performed once, that is, a laser beam is irradiated twice at one location to form holes p having a depth of about ½ of the substrate thickness t at a predetermined pitch (see FIG. 1). Since the diameter of the laser beam is the same as in the case of one-time processing, the risk of microcracks in the electronic component substrate 1 is low.

In this electronic component substrate 1, after forming the components of the electronic component in the portions of each pattern 4, for example, in the case of a thermal head, after forming a glaze layer, a heating resistor, an electrode pattern, etc., It is divided into individual patterns 4.

Table 1 below shows a comparison of the transverse rupture force F, the defect rate P, and the crack angle θ when the discard pattern is divided into five, in the case of the two-time laser treatment and the case of the one-time laser treatment. .

Here, as for the transverse rupture force F, as shown in FIG. 3, the electronic component substrate 1 is clamped by the jigs 6a and 6b, the jig 7 is mounted on the discard pattern 5, and the jig 7 is pushed. Pull gauge 8
This is a reading of the push-pull gauge 8 when the discard pattern 5 is broken by pressing with. Here, the thickness t and the width w of the electronic component substrate 1 are 1.05 mm and 55 mm, respectively. For reference, the dimensions l ₁ and l ₂ of jigs 6a and 6b are 23
mm and 73 mm. As shown in FIG. 4, the crack angle θ is an angle formed by the crack surface f and the direction perpendicular to the electronic component substrate 1, and the smaller the crack angle, the better the division.

As shown in Table 1, in the case of the double laser treatment, the transverse rupture force F, the defect rate P, and the crack angle θ are all smaller than in the case of the single laser treatment, and the discard pattern 5 can be easily formed. It can be confirmed that it can be divided into.

(F) Effects of the Invention As described above, the thermal head substrate of the present invention is characterized in that the scribe line that defines the end waste pattern is formed by performing laser processing twice. The advantage is that the discard pattern can be divided easily and the occurrence of division failure can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of an electronic component substrate (thermal head substrate) along a scribe line according to an embodiment of the present invention, FIG. 2 is a plan view of the electronic component substrate, and FIG. A perspective view illustrating bending strength measurement of an electronic component substrate,
FIG. 4 is a diagram for explaining a crack angle of a discard pattern of the electronic component substrate, FIG. 5 is a plan view of a conventional electronic component substrate, and FIG. 6 (a) is a conventional electronic component substrate. The figure which expands and shows the scribe line of a board | substrate, FIG.6 (b) is sectional drawing which follows the scribe line of the same conventional electronic component board | substrate. 1: Electronic component substrate, 5: Discard pattern, 2/3: Scribe line.

Claims (2)

[Claims] 1. A substrate for a thermal head having a substantially rectangular shape in which scribe lines are formed by laser processing and each pattern is divided, and a scribe line between each pattern is formed by laser processing once, and a substrate edge is formed. The scribe line that defines the side discard pattern is formed by performing laser processing twice, and is a substrate for a thermal head. 2. An electronic component provided with the substrate according to claim 1.