TWI675016B - Flat glass and method of forming message display portion on flat glass - Google Patents

Abstract

In the flat glass (1) of the present invention, an information display unit (3) with dots (6) as a unit is provided on a surface (2), and dots (6) are formed by annular grooves (7).

Description

Plate glass and method for forming message display portion on plate glass

The present invention relates to a flat glass and a method for forming a message display portion on the flat glass, and in particular, a technique for forming a message display portion in dot units on the surface of the flat glass.

In the manufacturing process of semiconductor wafers, flat glass is used as a component that supports semiconductor wafers. At this time, the semiconductor wafer is provided with a missing portion called a notch in order to bring the crystal orientation to a predetermined orientation. Therefore, the flat glass supporting the semiconductor wafer is generally provided with the same defect.

In addition, at this time, a mark is obtained on the surface of the flat glass that can obtain various information about the flat glass, and the mark is formed by a combination of characters, symbols, or graphics. These marks are, for example, formed by dot-shaped elements called dots. In the conventional technology, each point is irradiated with the surface of a flat glass by a laser, so that the laser irradiated area forms a slightly bottomed cylinder. Shaped recess (see, for example, Patent Document 1).

[Prior technical literature] [Patent Literature]

[Patent Document 1] JP H9-278494 A

However, with regard to this type of mark that uses dots as a constituent unit, the size of the mark and the point, and the center distance (pitch) of the point are generally set to predetermined specifications from the viewpoint of visibility and the like. Therefore, even the recessed portions constituting the dots must be formed based on the size (outer diameter, depth) of the specifications. However, this specification is a specification that is determined from a variety of viewpoints of satisfying mark visibility using dots as a unit of construction. Therefore, even if the specification is formed at a point (recess), the strength of the flat glass cannot be guaranteed. In particular, when the thickness is smaller, the volume ratio of the recessed portion occupying the mark formation region of the flat glass becomes larger, and the periphery of the recessed portion becomes relatively thin, which makes it difficult to ensure the required strength of the flat glass.

The problems described above are not limited to flat glass having a defective portion, and may also occur when any mark is formed on the surface of the flat glass with dots as constituent units. In addition, the above-mentioned problems, like a mark composed of words and the like, are not only a case of what is directly expressed in the appearance, like a two-dimensional code, what meaning is implied, and it is also suitable for the formation of When the reader reads and acquires (indirectly displays) the meaning.

In view of the foregoing, a problem to be solved in this specification is not to reduce the strength of the flat glass, and to form a highly visible message display portion on the surface.

In order to solve the aforementioned problems, the flat glass of the present invention is used to achieve this. That is to say, the flat glass is provided with an information display unit with dots as a unit on the surface, and the flat glass is characterized in that the dots are formed by annular grooves.

Therefore, the present invention is characterized in that when an information display unit having dots as a unit is provided on the surface of the flat glass, dots are formed by annular grooves. Because the point is formed by the annular groove, the area surrounded by the annular groove (the area more inward than the groove) is not removed by the laser and therefore remains. Therefore, compared with a conventionally-shaped (slightly bottomed cylindrical) recessed portion having the same outer diameter, the volume of the recessed portion of the present invention is greatly reduced, and it is possible to prevent the strong bottom of the region provided in the information display portion of the flat glass from decreasing. In addition, in the case of an annular groove, as long as the outer diameter is not changed, even if the width of the groove is reduced, the visibility will not be greatly reduced. Therefore, if the outer diameter of the groove is not changed and the width is reduced, the volume of the area more inward than the groove can be increased, and the required strength can be ensured while ensuring the visibility.

In addition, in the flat glass of the present invention, the groove may have a ring shape.

Since the dot is a constituent unit of the information display unit, from the viewpoint of making the dot universal, it is preferable to form the recognizable shape such that the groove forming the dot is symmetrical. Furthermore, since the groove is annular, especially a true annular shape, the versatility of the arrangement of the points formed by the groove can be improved.

Further, in the flat glass of the present invention, the outer diameter of the dot is also It may be 0.05 mm or more and 0.2 mm or less.

Because the outer diameter of the ring formed by such a dot recognition mode is prescribed, the strength required for flat glass can be ensured while satisfying the visibility of the message display unit composed of dots and dots.

In addition, in the flat glass of the present invention, the groove inner diameter at which the dots are formed may be 0.0375 mm or more and 0.125 mm or less.

Because the inner diameter of the ring formed by the identification mode of the dots is specified, the strength required for the flat glass can be ensured while satisfying the discrimination of the information display unit composed of dots and dots.

In the flat glass of the present invention, the depth of the grooves forming the dots may be 2.0 μm or more and 30 μm or less.

Because the depth of the constituent points is specified in this way, the strength required for the flat glass can be ensured while satisfying the visibility of the information display unit with the dots as the constituent units.

In addition, in the flat glass of the present invention, the center distance between adjacent points may be 0.06 mm or more and 0.25 mm or less.

Because the center-to-center distance between such adjacent points is specified, the strength required for the flat glass can be ensured while satisfying the visibility of the information display unit composed of points and points.

In addition, in the flat glass of the present invention, on the surface, the region divided by the groove into the inside of the groove and the region divided by the groove into the outside of the groove may be on the same plane.

The area formed on the surface of the glass plate is formed on the same plane as the area divided by the groove inside the groove and the area divided by the groove outside the groove. The outline of the ditch becomes sharper. Therefore, the visibility of the points formed by the groove can be further improved.

In addition, in the flat glass of the present invention, the surface is in the shape of a circular plate, and a positioning portion is provided in the surrounding portion. The center position in the circumferential direction of the information display portion may be determined based on the center position in the circumferential direction of the positioning portion. The direction is set within a range of 2 ° to 10 °.

With regard to the flat glass of the present invention, since the strength of the area where the information display portion is formed can be ensured, for example, the surface is formed into a circular plate in the manner described above, and in the flat glass provided with the positioning portion in the surrounding portion, The present invention is also applicable to a case where the information display portion is formed only at a position shifted by a predetermined phase angle in the circumferential direction.

In the flat glass of the present invention, the message display unit has one or more elements selected from the group consisting of characters, symbols, two-dimensional codes, and graphics; and elements composed of plural dots.

Therefore, when the message display unit has elements selected from characters, symbols, two-dimensional codes, and graphics, the elements such as characters may be composed of plural dots. Therefore, regardless of the type of the message display section, this element (so-called intermediate constituent unit) can be accurately displayed with dots (so-called minimum constituent unit).

In addition, in the flat glass of the present invention, the message display unit may display at least one of the size, linear expansion ratio, batch size, partial thickness ratio, manufacturer name, seller name, and material code of the flat glass. In addition, the dimensions here include the thickness, outer diameter, and the like of the flat glass (as described later, when a positioning portion such as a missing portion is provided in the flat glass, The depth of the missing portion, the size of the opening, and the like represent the shape and size of the positioning portion.

Regarding the flat glass of the present invention, regardless of the display method, various kinds of information can be displayed on the surface of the flat glass in a highly recognizable manner. For example, the information display section that displays the information exemplified above can be formed on the flat without a doubt The surface of the glass.

In addition, in order to solve the aforementioned problems, it is achieved by a method for forming a message display section of the present invention. That is, this method is characterized by a method of forming an information display portion on the surface of the flat glass, and the information display portion uses dots as a constituent unit, and dots are formed in an annular groove.

As described above, as for the method of forming the information display portion of the present invention, as with the flat glass of the present invention, dots are formed by annular grooves because the area surrounded by the annular grooves is left with the same outer diameter. The shape (slightly cylindrical shape) of the recessed portion significantly reduces the volume of the recessed portion. Therefore, it is possible to prevent the strong bottom of the area where the message display portion of the flat glass is provided from being lowered. In addition, in the case of an annular groove, as long as the outer diameter is not changed, there is no need to worry about greatly reducing the visibility even if the width of the groove is reduced. Therefore, if the outer diameter of the groove is not changed and the width is reduced, the volume of the area (the area surrounded by the groove) that is more inward than the groove can be increased, and the required strength can be ensured while ensuring visibility. Or, for the same reason, if the depth of the groove is made smaller than the depth of the concave portion of the conventional shape, the required strength can be secured while ensuring the visibility.

In addition, in the method for forming the information display portion of the present invention, the annular groove may be formed by forming an ablation by irradiating laser light.

When various marks are formed by irradiating laser light on the surface of an object (so-called laser marking), a region irradiated by the laser light is generally melted to form a recessed portion as a mark. However, when a laser mark is applied to a brittle material such as flat glass, it is necessary to pay attention to the strain (thermal strain) caused by the heat accumulated in the flat glass when irradiating the laser light. In other words, when the flat glass is formed by heating and melting the flat glass by the irradiation of the laser light, heat is accumulated in the area irradiated by the laser light and its surroundings. This heat accumulation causes strain on the surface of the sheet glass, which is a cause of the decrease in strength. In addition, because the melted part flows around and remains, it is difficult to form a groove with the correct shape and size following the movement trajectory of the pulse laser in the irradiation area.

In this regard, in the present invention, the annular groove is formed by irradiation and ablation of laser light, and the glass in the laser light irradiated area disappears due to vaporization. In addition, in order to form erosion, laser light with a high energy density is irradiated in a very short period of time, which can suppress the occurrence of heat accumulation in the area and surroundings of the laser light. Therefore, a groove can be formed while suppressing the occurrence of thermal strain, and the intensity of the area irradiated with the laser light can be ensured. In addition, grooves are formed by erosion. In order to reduce the flow of molten glass, grooves with the correct shape and size can be formed following the movement trajectory of the laser light irradiation area.

In addition, in this case, in the method for forming an information display unit of the present invention, the annular groove may be formed by scanning laser light in a ring shape.

In addition, in the method for forming an information display section of the present invention, the laser light is a pulsed laser, and the pulse width used may be in the picosecond to femtosecond range.

For example, using the commonly used nanosecond laser (pulse width is Nanosecond-level pulsed lasers) form such a mark, and if the irradiation conditions are precisely controlled, although the ablation can occur in the area irradiated with the laser light, in this case, more glass melts. On the other hand, if a pulse laser with a pulse width of picosecond to femtosecond level (so-called picosecond laser or femtosecond laser) is used, the pulse width is very short, so no heat accumulation is formed in the glass, so Ablation is formed only in the area irradiated with the laser light (the melting of the glass is not substantially generated around the area irradiated with the laser light). Therefore, it is possible to reliably prevent the occurrence of thermal strain and secure the strength more stably. In addition, since melting of glass can be prevented from flowing around, grooves can be formed only in the area irradiated with laser light, and it is expected that the shape accuracy and even the dimensional accuracy of the grooves can be improved. In addition, if it is a picosecond laser or a femtosecond laser, it is not necessary to consider the flow of the molten glass like the nanosecond laser. Since the irradiation conditions of the laser light can be set, the control can be simplified.

As described above, according to the present invention, a highly visible message display portion can be formed on the surface without reducing the strength of the flat glass.

1‧‧‧ flat glass

1a‧‧‧periphery

2‧‧‧ surface

2a, 2b ‧‧‧ divided area

3‧‧‧ Message Display Department

4‧‧‧ missing

5‧‧‧ text

6 o'clock

7‧‧‧ annular groove

10‧‧‧laser marking device

11‧‧‧ Pulse Laser

12‧‧‧laser oscillator

13, 14‧‧‧scanning mirror

13a, 14a‧‧‧Laser reflection surface

15‧‧‧ lens

16‧‧‧Support Desk

17, 18‧‧‧ scan motor

A1‧‧‧Laser Irradiation Area

Scanning trajectory of L1‧‧‧laser

[Fig. 1] A plan view of a flat glass according to an embodiment of the present invention.

[Fig. 2] An enlarged view of a main part of the flat glass shown in Fig. 1. [Fig.

[Fig. 3] An enlarged view of a portion A of the flat glass shown in Fig. 2. [Fig.

[Fig. 4] An enlarged view of a part B of the flat glass shown in Fig. 3. [Fig.

[Fig. 5] C-C sectional view of the flat glass shown in Fig. 4. [Fig.

6 is a perspective view illustrating the outline of a laser marking device according to an embodiment of the present invention.

[Fig. 7A] An enlarged plan view of a main part illustrating a method for forming an annular groove by using the laser marking device shown in Fig. 6. [Fig.

[Fig. 7B] An enlarged plan view of a main part illustrating a method of forming an annular groove by using the laser marking device shown in Fig. 6. [Fig.

FIG. 7C is an enlarged plan view of a main part illustrating a method of forming an annular groove using the laser marking device shown in FIG. 6. FIG.

[Embodiment]

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7C.

FIG. 1 is a plan view of a flat glass 1 according to an embodiment of the present invention. This plate glass 1 can be used as a semiconductor support substrate, for example. As shown in FIG. 1, an information display section 3 is formed on the surface 2 of the flat glass 1. In this embodiment, the flat glass 1 has a substantially circular plate shape. In addition, the peripheral portion 1 a of the flat glass 1 is provided with a missing portion 4 as a positioning portion, and a message display portion 3 is formed beside the missing portion 4.

The flat glass 1 is preferably in a wafer shape (slightly circular plate shape). In this case, the diameter is set to 100 mm or more and 500 mm or less, and preferably 150 mm or more and 450 mm or less. If you use this shape And the size of the flat glass 1 is more suitable for the manufacturing process of a semiconductor package.

In addition, for the above application, the plate thickness of the flat glass 1 is set to less than 2.0 mm, preferably 1.5 mm or less, more preferably 1.2 mm or less, still more preferably 1.1 mm or less, and still more preferably 1.0 mm or less. , The best is 0.9mm or less. This is because the smaller the thickness of the plate, the smaller the mass of the laminated body included in the flat glass 1 can be, and the handleability of the laminated body can be improved. On the other hand, if the thickness of the plate is too small, the strength of the flat glass 1 itself decreases, and a problem that the function as a support plate cannot be exerted occurs. Therefore, the plate thickness of the flat glass 1 is set to be 0.1 mm or more, preferably 0.2 mm or more, more preferably 0.3 mm or more, even more preferably 0.4 mm or more, still more preferably 0.5 mm, and even more preferably 0.6mm or more, preferably 0.7mm or more.

The message display unit 3 is enlarged and displayed as shown in part A in FIG. 2. For example, the message display unit 3 is composed of a plurality of characters 5 (the characters 5 referred to herein include at least ideographic characters such as the numbers shown in FIG. 2). Each character 5 is composed of a plurality of dots 6 as shown in FIG. 3.

Here, the configuration of each point 6 will be described in more detail. FIG. 4 is an enlarged view of point 6. As shown in the figure, each point 6 is formed by an annular groove 7. Therefore, each point 6 constituting the character 5 is recognized as a ring (FIGS. 3 and 4). In this embodiment, the groove 7 has a true annular shape. In addition, the outer peripheral edge and the inner peripheral edge of the groove 7 have a true circular shape together. Therefore, at this time, the width w of the groove 7 is kept constant around a circle.

In addition, in the surface 2 of the flat glass 1, a message is formed The area of the display section 3, that is, the area where the dots 6 are formed, is divided into a first divided area 2a inside the groove 7 by the annular groove 7, and a second divided area 2b outside the groove 7. At this time, as shown in FIG. 5, each of the divided regions 2 a and 2 b is flat and located on the same plane.

Next, the size of the loop groove 7 is described. First, the outer diameter d1 (FIG. 4) of the groove 7 is set to, for example, 0.05 mm or more and 0.20 mm or less, preferably 0.07 mm or more and 0.13 mm or less, and more preferably 0.09 mm or more and 0.11 mm or less. The inner diameter d2 (FIG. 4) of the structure is set to, for example, 0.035 mm or more and 0.14 mm or less, preferably 0.05 mm or more and 0.10 mm or less, and more preferably 0.06 mm or more and 0.08 mm or less. The depth d3 (FIG. 5) of the groove 7 is set to, for example, 2.0 μm or more and 30 μm or less, and preferably 4.0 μm or more and 15 μm or less. The distance d4 (FIG. 4) between the centers C1 and C2 of the adjacent grooves 7 and 7 is, for example, 0.06 mm or more and 0.25 mm or less, and preferably 0.10 mm or more and 0.16 mm or less. In addition, at this time, in order to prevent mutual interference between the grooves 7 and 7 adjacent to each other, the distance d4 between the centers C1 and C2 of the grooves 7 and 7 adjacent to each other is set to be larger than the outer diameter d1 of the groove 7 Even bigger. Specifically, the interval d5 between the grooves 7 and 7 adjacent to each other is set to 0.10 mm or more, and preferably 0.20 mm or more. The above dimensions are specified from the viewpoint of satisfying the visibility of the point 6 and the strength of the flat glass 1, particularly the strength of the area where the point 6 is formed.

In addition, as in the present embodiment, the surface 2 of the flat glass 1 has a circular plate shape. When a missing portion 4 serving as a positioning portion is provided in the peripheral portion 1a (FIG. 1), the circumferential center position C3 of the missing portion 4 is set as Benchmark In this case, the phase angle θ (FIG. 2) between C3 and the center position C4 in the circumferential direction of the message display section 3 is set to 2 ° or more and 10 ° or less, preferably 3 ° or more and 7 ° or less.

Therefore, in the present invention, when a character 5 having dots 6 as a unit and a message display unit 3 formed by combining plural characters 5 are provided on the surface 2 of the flat glass 1, the dots 6 are formed by the annular groove 7. Since the point 6 is formed by the annular groove 7, the area surrounded by the annular groove 7 (the area inside the groove) is left. Therefore, the volume of the recessed portion (annular groove 7) of the present invention is significantly reduced as compared with the recessed portion of the conventional shape (slightly cylindrical) having the same outer diameter d1. Therefore, it is possible to prevent the intensity of the area where the message display section 3 is provided on the flat glass 1 from being lowered. In addition, in the case of the annular groove 7, as long as the outer diameter d1 is not changed, even if the width w of the groove 7 is reduced, the visibility is not greatly reduced. Therefore, if the outer diameter d1 of the groove 7 is not changed and the width w is reduced, the volume of the area more inward than the groove 7 can be increased, and the required strength can be ensured while ensuring the visibility.

The flat glass 1 configured as described above can be formed by a laser light method. This is described in more detail below.

FIG. 6 is a configuration example of a laser marking device 10 according to an embodiment of the present invention. As shown in the figure, the laser marking device 10 includes a laser oscillator 12 capable of oscillating a pulse laser 11 having a predetermined pulse width, and controls two-dimensional irradiation of the pulse laser 11 oscillated by the laser oscillator 12. The first and second scanning mirrors 13 and 14 and the pulsed laser 11 controlled by the first and second scanning mirrors 13 and 14 are lenses 15 for collecting light at the two-dimensional irradiation position.

Therefore, at this time, the pulse laser 11 oscillated from the laser oscillator 12 is reflected by the first laser reflecting surface 13 a of the first scanning mirror 13, and the reflected pulse laser 11 is reflected by the second scanning again. The second laser reflection surface 14 a of the mirror 14 reflects the predetermined portion of the plate glass 1 supported on the support table 16 through the lens 15, that is, the pulse laser 11 is irradiated on the area where the information display portion 3 will be formed. In addition, at this time, the first scanner motor 17 connected to the first scanning mirror 13 is rotationally driven, the phase of the first laser reflecting surface 13 a of the first scanning mirror 13 is adjusted, and the second scanning mirror 14 is rotationally driven. The second scanner motor 18 adjusts the phase of the second laser reflecting surface 14a of the second scanning mirror 14 and sets the scanning trajectory L1 of the pulse laser 11 irradiating the surface 2 of the flat glass 1 (refer to FIGS. 7A to 7C described later) ).

In addition, at this time, one of the irradiation conditions of the pulse laser 11 oscillated from the laser oscillator 12 is as follows, for example. That is, the pulse width of the pulse laser 11 is set to a picosecond level, preferably a femtosecond level, and specifically set to a setting of 10 fs or more and 500,000 fs (500 ps) or less. In addition, while setting the wavelength of the pulsed laser 11 to 200 nm or more and 2500 nm or less, the repetition frequency is set to 1 Hz or more and 1 G (giga) Hz or less. In addition, the beam diameter of the pulse laser 11 is set to be 1 μm or more and 100 μm or less, and the scanning speed, that is, the moving speed of the pulse laser 11 on the scanning trajectory L1 shown in FIGS. 7A to 7C is set to The repetition frequency is 1 mm / s or more and 800 mm / s or less.

Next, the point 6 used for the laser marking device 10 configured as described above and the character 5 (message display portion 3) including the point 6 will be described. Formation method.

First, as shown in FIG. 7A, while the pulse laser 11 is irradiated to the scan starting point P0 on a predetermined scan track L1, scanning is started along the scan track L1 of the pulse laser 11. By this irradiation operation, the ablation is formed in the irradiation area A1 of the pulse laser 11, so that the scanning starting point P0 is used as a starting point, and a groove is formed along the scanning locus L1 with a predetermined width w and according to the outer diameter of the irradiation area A1. 7 (Figure 4, Figure 7B).

Next, the scanning trajectory L1 is slightly circled, and when the irradiation center of the pulse laser 11 returns to the scanning starting point P0, scanning and irradiation of the pulse laser 11 are stopped. Thereby, the ring-shaped groove 7 is closed along the scanning locus L1 (FIG. 7C).

With this method, after forming one point 6, the focus of the laser 11 is moved in a predetermined formation area of the adjacent point 6, and the pulse laser 11 is irradiated with the state shown in Figs. 7A to 7C. Irradiation causes erosion, forming an annular groove 7 constituting the point 6. By repeating the irradiation action to the predetermined formation area on all the points 6 constituting a character 5, the corresponding plural points 6, that is, a character 5 is formed by using the plural points 6 as a unit (FIG. 2) .

Then, the above operations are repeated for the predetermined formation area of other characters 5, and the plural characters 5 forming the message display section 3 are formed by corresponding plural points 6 (FIGS. 2 and 3).

By this method, in the present invention, since the annular groove 7 constituting each point 6 is formed by the ablation by the irradiation of the pulse laser 11, the glass cause of the area irradiated by the pulse laser 11 (that is, the irradiation area A1) gasification And disappear. In addition, in order to form erosion, the pulse laser 11 with a high energy density is irradiated in a very short period of time, and heat accumulation in the irradiation area A1 of the pulse laser 11 and the surrounding area can be suppressed. Therefore, the groove 7 can be formed while suppressing the occurrence of thermal strain, and the intensity of the irradiation area A1 of the pulse laser 11 can be secured. In addition, the grooves 7 are formed by ablation. In order to greatly reduce the flow of molten glass around the grooves, the grooves 7 with the correct shape and size can be formed following the movement trajectory (scanning trajectory L1) of the irradiation area A1 of the pulsed laser 11.

In the present embodiment, as the pulse laser 11, a pulse laser (a so-called picosecond laser or femtosecond laser) having a pulse width in the picosecond to femtosecond range is used. With this type of laser light, the very short pulse width characteristic can be used, and only when the plate glass 1 does not generate heat accumulation, only the ablation can be formed in the irradiation area A1 of the pulse laser 11. Then, it is possible to surely prevent the occurrence of thermal strain and secure a more stable strength of the flat glass 1. In addition, since the molten glass can be prevented from flowing around, the correct groove 7 can be formed only in the irradiation area A1 of the pulsed laser 11. Speaking of this embodiment, in the surface 2 of the sheet glass 1, the first divided region 2a divided by the annular groove 7 on the inner side and the second divided region divided by the outer groove 7 2b is formed on the same plane in a flat manner together, so it has good visibility. In addition, if it is a picosecond laser or a femtosecond laser, it is not necessary to consider the flow of the molten glass like the nanosecond laser, because the irradiation conditions of the pulse laser 11 can be set, and the control can be simplified.

In addition, as in this embodiment, if the annular groove 7 is formed by irradiating the pulse laser 11, compared with the case where the groove 7 has a polygonal shape such as a rectangle, the deviation of the irradiation energy of the pulse laser 11 can be suppressed ( According to Shooting time deviation). As a result, the grooves 7 controlled to have a highly accurate shape and size can be formed. Of course, if the shape accuracy and dimensional accuracy are higher, there are fewer defect parts in the strength, and the strength can be further improved.

As mentioned above, although one embodiment of the present invention is described as an example, the formation method of the flat glass 1 and the information display unit 3 described above can be arbitrarily changed within the scope of the present invention.

For example, the shape of the groove 7 is exemplified as a ring shape (FIG. 4), but it is not limited to this shape. For example, although the illustration is omitted, a polygonal shape such as a rectangular shape may be formed to form a non-circular groove 7. Alternatively, the groove 7 is formed in a point-symmetric shape at the center (center of gravity) of the groove 7 such as a polygon or a cymbal pattern.

In addition, in the above-mentioned embodiment, as shown in FIG. 4 and the like, although the annular groove 7 is formed in a completely closed form, it is not necessarily limited to this form. The annular groove 7 may be formed in a partially open form within a range that does not cause discrimination problems, such as a C-shape. If such a groove 7 is formed, for example, when the annular groove 7 is formed by irradiating the pulse laser 11 in the manner described above, the irradiation area A1 is overlapped due to the scanning of the pulse laser 11, which can prevent the overlapped portion Variations in the shape or width w of the grooves 7 formed.

In addition, in the above-mentioned embodiment, the case where only one annular groove 7 is formed corresponding to one point 6 is exemplified, but it is not necessarily limited to this form. For example, although the illustration is omitted, for the purpose of improving the visibility, a dot-shaped recess may be formed at the center of the inside of the annular groove 7 (in FIG. 4, the first divided region 2a) to form the outer contour of the point 6. . Or at the point of formation 6 The outer groove of the annular groove 7 can be formed inside the annular groove.

In addition, regarding the aspect of forming the point 6 by the pulsed laser 11, in the above embodiment, one pulse laser 11 is irradiated and scanned, and only one ring groove 7 is formed in the irradiated and scanned area. However, in order to improve the working efficiency, the annular groove 7 constituting the point 6 may be formed at the same time. In this case, for example, although the illustration is omitted, the pulsed laser is divided into 11 beams by a conventional beam splitter or a spatial beam phase modulator such as a conventional beam splitting means. The shots 11 are irradiated and scanned on predetermined formation areas corresponding to the points 6 respectively, and a plurality of grooves 7 (that is, a plurality of points 6) can be formed simultaneously (once).

In addition, in the above-mentioned embodiment, as the means for forming the annular groove 7 constituting the point 6, although the form in which the pulse laser 11 is scanned by the laser marking device 10 is exemplified, it is not necessarily limited to this form. For example, although the illustration is omitted, a predetermined mask is irradiated with laser light, and the laser irradiation object (flat glass 1) passing through the mask can imitate the shape of a transmission pattern formed in advance in the mask to form a ring groove 7 .

In addition, in the above description, although the present invention exemplifies the formation of the defective portion 4 on the peripheral portion 1 a of the surface 2 of the flat glass 1, the positioning of the peripheral portion 1 a of the flat glass 1 other than the defective portion 4 is also applicable to the present invention. Of course, if the information display section 3 having the dot 6 as a unit is formed on the surface 2 of the flat glass 1, it is also applicable to the present invention without forming a positioning section.

Claims (12)

A flat glass is provided with a message display unit with dots as a unit on the surface. The flat glass is characterized in that the aforementioned dots are formed by annular grooves; the inner diameter of the aforementioned grooves is 0.035 mm or more and 0.14 mm or less; The distance between the centers of the adjacent grooves is larger than the outer diameter of the grooves; the surface is divided by the grooves into an inner divided area located inside the groove and an outer divided area located outside the groove; The inner divided region and the outer divided region are both flat. The flat glass of claim 1, wherein the groove is annular. The flat glass of claim 1 or 2, wherein the outer diameter of the aforementioned point is 0.05 mm or more and 0.2 mm or less. The flat glass of claim 1 or 2, wherein the depth of the grooves forming the dots is 2.0 μm or more and 30 μm or less. The flat glass of claim 1 or 2, wherein the inner divided region and the outer divided region are on the same plane. For example, the flat glass of claim 1 or 2, wherein the center-to-center distance between adjacent points is 0.06 mm or more and 0.25 mm or less. For example, the flat glass of claim 1 or 2, wherein it has a circular plate shape and is provided with a positioning portion around the center; the center position in the circumferential direction of the information display portion is based on the center position in the circumferential direction of the positioning portion. Above 2 ° in the circumferential direction And set within 10 °. For example, the flat glass of claim 1 or 2, wherein the information display unit has one or more elements selected from the group consisting of characters, symbols, two-dimensional codes, and graphics; and the plurality of dots constitute the one or more of the aforementioned elements. Elements. For example, the flat glass of claim 1 or 2, wherein the information display section displays at least one selected from among the size, linear expansion ratio, batch size, partial thickness ratio, manufacturer name, seller name, and material code of the flat glass. 1 message. A method for forming an information display portion is a method of forming an information display portion on the surface of a flat glass, characterized in that the aforementioned information display portion is constituted by dots; and the aforementioned dots are formed by annular grooves. The inner diameter of the groove is set to be 0.035 mm or more and 0.14 mm or less, and the distance between the centers of the grooves adjacent to each other is larger than the outer diameter of the groove; the surface is divided by the groove to be located inside the groove. A flat inner divided area and a flat outer divided area located outside the groove are formed; and the annular groove is formed by irradiating laser light to perform ablation. The method for forming an information display unit according to claim 10, wherein the annular groove is formed by scanning the laser light in a ring shape. For example, the method for forming an information display section of claim 10 or 11, wherein the laser light is a pulse laser, and a pulse width used is in the picosecond to femtosecond range.