TWI877245B - Scoring Wheel - Google Patents

Abstract

The purpose of the present invention is to provide a scribing wheel that can form vertical cracks of sufficient depth on a substrate and improve the end surface strength. The scribing wheel 100 has: a plurality of blades 101 formed along the outer periphery; and a plurality of grooves 102, which are arranged between the blades 101 adjacent to each other in the circumferential direction and are recessed on the side of the central axis L0. When the groove 102 is observed in a direction parallel to the central axis L0, the angle formed by the ridge line at the end thereof is greater than the angle formed by the ridge line at the deepest part, and the angle formed by the ridge line at the end is greater than 155 degrees.

Description

Scoring Wheel

The present invention relates to a scribing wheel for forming scribing lines on brittle material substrates such as glass substrates.

The breaking of a brittle material substrate such as a glass substrate is performed by a scribing step of forming a scribing line on the substrate surface and a breaking step of breaking the substrate along the formed scribing line. In the scribing step, a scribing wheel is pressed against the substrate surface and moves along a specific line. Thus, the scribing wheel rolls on the substrate surface to form a scribing line.

The following patent document 1 describes a scribing wheel having a plurality of grooves formed at a specific pitch on the peripheral ridge line. By using a scribing wheel having this structure, vertical cracks can be reliably formed on the substrate immediately after scribing begins, and deeper vertical cracks can be formed. [Prior art document] [Patent document]

[Patent Document 1] Japanese Patent Publication No. 09-188534

When using the scribing wheel of the above structure, scribing marks are intermittently formed at a specific interval on the substrate surface, and are connected to the vertical cracks formed directly below the scribing marks, thereby forming scribing lines. Furthermore, it is known that the scribing quality varies depending on the shape of the groove. Although the groove needs to be deepened to form a deeper vertical crack, there is a case where the end surface strength of the substrate after cutting is reduced.

In view of this problem, the purpose of the present invention is to provide a scribing wheel that can form vertical cracks of sufficient depth on a substrate and improve the end surface strength.

The main aspect of the present invention is a scribing wheel for forming scribing lines on a substrate. The scribing wheel of this aspect has: a plurality of blades formed along the outer periphery; and a plurality of grooves disposed between the blades adjacent to each other in the circumferential direction and recessed on the central axis side. Here, when the groove is observed in a direction parallel to the central axis, the angle formed by the tangents at the boundary position of the groove and the blade is greater than the angle formed by the ridge line of the deepest part, and the angle formed by the tangents at the boundary position of the groove and the blade is greater than 155 degrees.

According to the scribing wheel of this embodiment, when the scribing wheel rolls on the substrate surface, the portion near the blade bites into the substrate, forming a scratch on the substrate surface. At this time, since the groove has the above-mentioned shape, the interval of the scratch formed under low load becomes narrower, and it is easy to connect with the vertical crack formed at the scratch position. Furthermore, the angle change of the end of the groove, that is, the boundary between the blade and the groove, is gentle, and it is not easy to cause damage to the substrate. Therefore, the end surface strength of the substrate after cutting can be improved.

In the scribing wheel of this aspect, the groove is formed so that the grooves on both sides of the deepest part in the circumferential direction are curved when viewed in a direction parallel to the central axis. Thus, as the scribing wheel rolls, the grooves bite into the substrate smoothly. Thus, vertical cracks can be smoothly formed on the substrate.

As described above, according to the present invention, a scribing wheel can be provided which can improve the end surface strength of a substrate after cutting by means of a simple structure.

The effects and significance of the present invention will be further clarified by the following description of the embodiments. However, the embodiments shown below are only examples of the present invention, and the present invention is not limited to the embodiments described below.

The following is a description of the embodiments of the present invention with reference to the drawings. For convenience, each drawing is labeled with mutually orthogonal X-axis, Y-axis and Z-axis. The Z-axis is parallel to the center axis of the scribing wheel.

Fig. 1 (a) and (b) are a side view and a front view respectively schematically showing the structure of the scribing wheel 100. Fig. 1 (c) is a diagram showing a portion of the outer periphery of the scribing wheel 100 in an enlarged manner.

The scribing wheel 100 has a circular plate shape with the edges of both sides of the outer circumference cut off obliquely. Two inclined surfaces 100a inclined in different directions are formed on the outer circumference of the scribing wheel 100 when viewed from the side. A plurality of blades 101 including ridges are formed by the intersection of the two inclined surfaces 100a, and a groove 102 recessed on the central axis L0 side is formed between the blades 101 adjacent to each other in the circumferential direction. The lengths of the blades 101 in the circumferential direction are equal to each other. Moreover, the lengths of the grooves 102 in the circumferential direction are also equal to each other. Therefore, the spacing between the blades 101 in the circumferential direction is fixed, and the spacing between the grooves 102 in the circumferential direction is also fixed.

The scribing wheel 100 is formed of a superhard alloy, sintered diamond, single crystal diamond or multi-crystal diamond. A circular hole 100b is formed in the center of the scribing wheel 100 for inserting a shaft serving as a rotating shaft. The scribing wheel 100 has a diameter of about 1 mm to 5 mm and a thickness of about 0.4 mm to 1 mm. In addition, the angle of the blade 101, that is, the angle formed by the two inclined surfaces 100a, is about 100 to 160°, and the diameter of the hole 100b is about 0.4 to 1.5 mm.

The spacing p1 of the grooves 102 (the sum of the circumferential length (L1) of one groove 102 and the circumferential length (L2) of one blade 101) is, for example, about 10 to 100 μm. The depth d1 of the groove (the difference in radial distance between the ridge line of the blade 101 and the deepest part of the groove 102 on the scribing wheel 100) is, for example, about 1 to 10 μm. The length of the area that is more recessed than the ridge line of the blade 101 on the outer periphery of the scribing wheel 100, that is, the circumferential length (L1) of the groove 102 is, for example, about 3 to 40 μm. In addition, a ridge line similar to that of the blade 101 is formed inside the groove 102.

FIG. 2 is a diagram for explaining the shape of the groove portion 102 of the scribing wheel 100 when viewed from a direction parallel to the central axis L0.

As shown in FIG. 2 , a groove 102 having a circumferential width of W is formed between adjacent blades 101. When viewed from a direction parallel to the center axis L0 (Z-axis direction), the portions of the groove 102 on both sides of the circumferential direction relative to the deepest portion 102a are convex in a direction away from the center axis L0. That is, the angle at which the ridge lines of the blade 101 and the groove 102 intersect at the boundary positions P3 and P4, i.e., the end groove angle, is different from the angle formed by the ridge line of the groove 102 at the deepest portion 102a, i.e., the bottom groove angle, and the end groove angle is greater than the bottom groove angle. Here, the angle formed by the ridge line of the groove 102 and the ridge line of the blade 101 on both sides of the circumferential direction relative to the deepest portion 102a changes at positions P1 and P2. 2 for the sake of explanation, the blade portion 101 and the groove portion 102 are set to be a shape consisting of straight lines, but in fact, the shape includes a curved line.

At the boundary positions P3 and P4 between the groove portion 102 and the blade portion 101, tangents Ln1 and Ln2 are set at the end of the groove 102, and the angle 20 formed by the tangents Ln1 and Ln2 is set as the end groove angle θ1. In addition, tangents Ln3 and Ln4 are set at the two side parts of the deepest portion 102a, and the angle formed by the tangents Ln3 and Ln4 is set as the bottom groove angle θ2. In this embodiment, θ1 is greater than θ2. In addition, θ1 is greater than 155 degrees, preferably greater than 160 degrees, and more preferably greater than 165 degrees. Thereby, the deepest portion 102a is located closer to the center axis side of the scribing wheel than the intersection of the tangents Ln1 and Ln2.

Thus, in the scribing wheel 100, if the angle formed by the tangent of the groove at the boundary position between the blade 101 and the groove 102, i.e., the end groove angle θ1, is set to be 155 degrees or more, then, especially when the scribing load is relatively small, the volume of the portion that bites into the substrate becomes larger, and the interval between the portions that bite into the substrate becomes narrower. Thus, it is easier to generate vertical cracks with a lower load. In addition, since the angle between the blade 101 and the groove 102 at the boundary positions P3 and P4 between the blade 101 and the groove 102 is more blunt, the impact on the substrate can be further reduced, and the end surface strength of the substrate after the cut can be improved in conjunction with the relatively small scribing load.

Furthermore, since the bottom groove angle θ2 of the bottom of the groove is smaller than the end groove angle θ1, the groove depth d1 and the groove width can be individually changed according to the type and thickness of the substrate.

<Experimental example> The inventors used the scribing wheel 100 of Experimental Examples 1 to 6 in which the angle θ1 of the groove end was changed in six stages to perform scribing evaluation. A glass substrate with a thickness of 0.4 mm was used as a brittle material substrate. The scribing speed was set to 100 mm/sec. The structure other than the shape of the groove portion 102 when observed along the direction of the central axis L0 was the same as that of the scribing wheel of Experimental Examples 1 to 6, with an outer diameter of 2.0 mm, a thickness of 0.65 mm, and a blade tip angle of 115 degrees.

FIG3 is a table related to the scribing wheels of Experimental Examples 1 to 6. As shown in FIG3, the angle θ1 of the end groove of the scribing wheel 100 is 165.2 degrees in Experimental Example 1, 162.7 degrees in Experimental Example 2, 157.8 degrees in Experimental Example 3, 154.0 degrees in Experimental Example 4, 153.4 degrees in Experimental Example 5, and 150.0 degrees in Experimental Example 6. By using these scribing wheels, the load is changed each time a scribing line is formed, and it is confirmed that ribs can be formed on the substrate and the load range is good for the scribing quality.

As shown in Figure 3, the minimum load for forming ribs in Experimental Examples 1 to 6 is 5.0 to 6.5 N, and there is a tendency that the larger the angle θ1 of the groove end, the smaller the minimum load. The maximum load for obtaining good quality lines is 14.5 to 15.0 N, and the change caused by the angle θ1 of the groove end is smaller than the minimum load.

Next, use each scribing wheel to form a scribing line with a load 0.5 N higher than the minimum load shown in Figure 3, and measure the end strength of the 20 specimens after segmentation by a 4-point bending test.

FIG. 4 is a graph showing the end face strength of the substrate after being cut in the scribing test using the scribing wheels of Experimental Examples 1 to 6. In FIG. 4 , the average value of the end face strength is shown as a numerical value, and the maximum and minimum values are shown as bars. The bar graph below shows the standard deviation. As shown in FIG. 4 , the average value of the end face strength is 121.0 N in the scribing wheel of Experimental Example 1, and is 110.0 N in the scribing wheel of Experimental Example 2. In addition, in the scribing wheels of Experimental Examples 1 and 2, it can be seen that the minimum value of the end face strength exceeds 100 N, and the standard deviation also tends to be lower. On the other hand, in the scribing wheel of Experimental Example 1, the average value of the end face strength is 89.5 N, which is a sufficiently high value. In contrast, the end surface strengths of the scoring wheels in Experimental Examples 4, 5, and 6 are 73.3 N, 53.0 N, and 51.3 N, respectively.

Thus, it was confirmed that by using the scribing wheel 100 with an end groove angle θ of 155 degrees or more, the end surface strength of the substrate after being cut with a load near the minimum load that can form a scribing line can be greatly improved compared with the previous one. Thus, it was confirmed that by using the scribing wheel 100 of the embodiment, a good scribing line can be formed even with a lower load.

<Examples of Changes> The implementation of the present invention may be subject to various changes other than those described above.

For example, in the above-mentioned embodiment, as shown in FIG. 2 , when viewed from a direction parallel to the central axis L0, the shape includes a straight line portion, but the shape of the portion is not limited thereto and can be appropriately changed as long as it bulges in a direction away from the central axis L0. For example, the shape of the two side portions of the deepest portion 102a can also be set to a curved shape whose curvature changes toward the deepest portion 102a.

Furthermore, the length of the ridgeline of the circumferential blade portion 101 can be appropriately adjusted according to the number of grooves 102 formed on the outer periphery of the scribing wheel 100. Similarly, the width W of the circumferential groove 102 can also be appropriately adjusted according to the number of grooves 102 formed on the outer periphery of the scribing wheel 100.

In addition, in the above-mentioned embodiment, as shown in Figures 1(b) and (c), although the groove portion 102 has a ridge line inside, the shape of the groove portion 102 when observed in the circumferential direction may also be a curved surface shape that bulges away from the center axis, or a shape that includes a plane perpendicular to the radial direction, and other shapes.

In addition, the embodiments of the present invention may be appropriately modified within the scope of the technical concept shown in the scope of the patent application.

100: Scribing wheel 100a: Inclined surface 100b: Hole 101: Blade 102: Groove 102a: Deepest part d1: Depth L0: Center axis L1: Length L2: Length Ln1: Tangent Ln2: Tangent Ln3: Tangent Ln4: Tangent p1: Pitch P1: Position P2: Position P3: Boundary position P4: Boundary position W: Width X: Axis Y: Axis Z: Axis θ1: End groove angle θ2: Bottom groove angle

Fig. 1 (a) and (b) are schematic side and front views of the scribing wheel of the embodiment, respectively. Fig. 1 (c) is an enlarged view showing a portion near the outer periphery of the scribing wheel of the embodiment. Fig. 2 is a diagram for explaining the shape of the groove of the scribing wheel of the embodiment when observed in a direction parallel to the center axis. Fig. 3 is a diagram showing the load of the scribing test using the scribing wheel of Experimental Examples 1 to 6. Fig. 4 is a diagram showing the end face strength of the substrate after being broken in the scribing test using the scribing wheel of Experimental Examples 1 to 6.

100: Scoring wheel

100a: Inclined surface

100b: hole

101: Blade

102: Groove

d1: depth

L0: Center axis

L1: Length

L2: Length

p1: Spacing

Claims (2)

A scribing wheel is characterized in that it is used to form scribing lines on a substrate and has: a plurality of blades, which include ridges formed along the outer periphery; and a plurality of grooves, which are arranged between the blades adjacent to each other in the circumferential direction and are recessed on the central axis side; a ridge is formed inside the groove, and when observed in a direction parallel to the central axis, the angle formed by the tangents at the boundary position of the groove and the blade is greater than the angle formed by the ridge at the deepest part, and the angle formed by the tangents at the boundary position of the groove and the blade is greater than 155 degrees. As in claim 1, the scoring wheel, wherein the groove portion, relative to the deepest portion, on both sides of the circumferential direction is in a curved shape when observed along a direction parallel to the central axis.