TW201706227A - Plate glass and method for forming information display section on plate glass - Google Patents

Abstract

A plate glass 1 according to the present invention is provided with, on a surface 2 thereof, an information display section 3 of which the constitutional unit is a dot 6, and the dot 6 is formed at a circular groove 7.

Description

Flat glass and method of forming message display portion on flat glass

The present invention relates to a flat glass and a method of forming a message display portion of the flat glass, and more particularly to a technique of forming a message display portion having a dot as a unit on the surface of the flat glass.

In the fabrication of semiconductor wafers, flat glass is used as a component to support the semiconductor wafer. At this time, in order to make the crystal orientation conform to a predetermined orientation, the semiconductor wafer is provided with a missing portion called a notch. Therefore, the flat glass supporting the semiconductor wafer is generally provided with the same missing portion.

Further, at this time, on the surface of the flat glass, a mark for obtaining various kinds of information about the flat glass or the like is formed, wherein the mark is formed by a combination of characters, symbols, or figures. These marks are, for example, composed of a dot-shaped element called a dot as a constituent unit. In the prior art, each point is a surface irradiated with a laser to irradiate the flat glass, so that the irradiated area of the laser is formed into a slightly bottomed cylinder. A concave portion (for example, refer to Patent Document 1).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP H9-278494 A

However, such a mark having a dot as a constituent unit is generally set to a predetermined size from the viewpoint of visibility and the like, the size of the mark and the center distance (pitch) of the dot. Therefore, even the concave portion constituting the dot must be formed based on the size (outer diameter, depth) of the specification. However, this specification is based on various specifications that satisfy the mark identification from the point of the constituent unit. Therefore, the strength of the flat glass cannot be ensured even if it is combined with the specification forming point (concave portion). In particular, when the thickness is small, the volume ratio of the concave portion occupying the mark forming region of the flat glass is larger, and the periphery of the concave portion is relatively thinner, which may make it difficult to secure the strength required for the flat glass.

The above-mentioned problems are not limited to the flat glass having the missing portion, and may occur even when any mark having a dot as a constituent unit is formed on the surface of the flat glass. In addition, the above-mentioned problems, like the combination of characters and the like, are not only a situation in which a meaning is directly expressed in the appearance, but a meaning of a two-dimensional code, which is also suitable for formation. The case where the reader reads (indirectly displays) the meaning of the object.

In view of the above, the problem to be solved by the present specification is that the strength of the flat glass is not lowered, and a highly recognizable information display portion is formed on the surface.

In order to solve the aforementioned problems, it is achieved by the flat glass of the present invention. That is, the flat glass is provided with a message display portion having a dot as a unit on the surface, and the flat glass is characterized in that the dots are formed by the annular groove.

Therefore, the present invention is characterized in that when a message display portion having a dot as a constituent unit is provided on the surface of the flat glass, a dot is formed by the annular groove. Since the dot is formed by the annular groove, the region surrounded by the annular groove (the region further inside than the groove) is not removed by the laser and remains. Therefore, compared with the concave portion of the conventional shape (slightly cylindrical shape) having the same outer diameter, since the volume of the concave portion of the present invention is greatly reduced, the strength of the region provided in the information display portion of the flat glass can be prevented from being lowered. Further, in the case of the annular groove, the visibility is not greatly lowered even if the width of the groove is not changed without changing the outer diameter. Therefore, if the width is lowered without changing the outer diameter of the groove, the volume of the inner side of the groove can be increased, and the required strength can be ensured while ensuring the visibility.

Further, in the flat glass of the present invention, the groove may have an annular shape.

Since the dot is a constituent unit of the message display portion, it is preferable to form the groove forming the dot into point symmetry from the viewpoint of making the dot have versatility. Further, since the groove has an annular shape, particularly a true annular shape, the versatility of the arrangement of the dots 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.

Since the outer diameter of the ring formed by the identification pattern of the dots is specified, the visibility of the information display portion having the point and the point as the constituent unit is satisfied, and the strength required for the flat glass can be secured.

Further, in the sheet glass of the present invention, the inner diameter of the groove forming the dots may be 0.0375 mm or more and 0.125 mm or less.

By specifying the inner diameter of the ring formed by the identification pattern of the dots, it is possible to ensure the strength required for the flat glass while satisfying the visibility of the information display portion in which the dots and dots are constituent units.

Further, in the sheet glass of the present invention, the depth of the groove forming the dots may be 2.0 μm or more and 30 μm or less.

By specifying the depth of the constituent points as described above, it is possible to ensure the strength required for the flat glass while satisfying the visibility of the information display portion in which the dots and dots are constituent units.

Further, in the sheet glass of the present invention, the center-to-center spacing of adjacent dots may be 0.06 mm or more and 0.25 mm or less.

Since the center-to-center spacing of such adjacent dots is specified, the strength required for the flat glass can be ensured while satisfying the visibility of the information display portion in which the dots and dots are constituent units.

Further, in the sheet glass of the present invention, the area defined by the groove as the inner side of the groove and the area defined by the groove as the outer side of the groove may be on the same plane.

The surface defined by the groove as the inner side of the groove is formed on the same plane as the area defined by the groove as the outer side of the groove, and is formed on the surface of the glass plate. The outline of the ditch becomes more vivid. Therefore, the visibility of the dots formed by the grooves can be further improved.

Further, in the sheet glass of the present invention, the surface has a disk shape, and a positioning portion is provided in the peripheral portion, and a central position in the circumferential direction of the information display portion is defined by a central position in the circumferential direction of the positioning portion as a reference. The direction is set within a range of 2° or more and 10° or less.

According to the flat glass of the present invention, since the strength of the region where the information display portion is formed can be ensured, for example, in the above-described manner, the surface is formed into a disk shape, and in the flat glass in which the positioning portion is provided in the peripheral portion, the side of the positioning portion is The case where the information display portion is formed only in a position in which the circumferential direction is shifted by a predetermined phase angle is also applicable to the present invention.

Further, 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 a plurality of dots.

Therefore, when the message display unit has elements selected from the group consisting of characters, symbols, two-dimensional codes, and graphics, elements such as characters can be composed of a plurality of points. Therefore, regardless of the type of the message display portion, the element (so-called intermediate constituent unit) can be correctly displayed by a dot (a so-called minimum constituent unit).

Further, in the flat glass of the present invention, the message display portion may display at least one of the size of the flat glass, the linear expansion ratio, the batch size, the partial thickness ratio, the manufacturer name, the seller name, and the material code. In addition, the size referred to herein includes the thickness, the outer diameter, and the like of the flat glass (as will be described later, when the flat glass is provided with a positioning portion such as a missing portion, The depth of the missing portion, the size of the opening, and the like, the size of the portion representing the shape and size of the positioning portion).

Regarding the flat glass of the present invention, regardless of the manner of display, since various kinds of information can be displayed on the surface of the flat glass in a highly recognizable manner, for example, the information display portion displaying the above-exemplified information can be formed on the flat panel without any problem. The surface of the glass.

Further, in order to solve the above problem, it is achieved by the method of forming the message display portion of the present invention. That is, this method is characterized by a method of forming a message display portion on the surface of the flat glass, and the message display portion is formed by dots and formed by dots.

As described above, the method of forming the message display portion according to the present invention, like the flat glass of the present invention, forms a dot by the annular groove, and the same as the outer diameter is left because the region surrounded by the annular groove is left. The volume of the recess is greatly reduced as compared with the recess of the shape (slightly cylindrical shape). Therefore, it is possible to prevent the strong bottom of the area where the information display portion of the flat glass is set from being lowered. Further, in the case of the annular groove, it is not necessary to reduce the width of the groove, and there is no fear that the visibility is greatly lowered. Therefore, if the width is lowered without changing the outer diameter of the groove, the volume of the inner side of the groove (the area surrounded by the groove) can be increased, and the required strength can be ensured while ensuring the 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 ensured while ensuring the visibility.

Further, in the method of forming the message display portion of the present invention, the annular groove may be formed by irradiating the laser light to form ablation.

When various marks are formed on the surface of the object by irradiating the laser light (so-called laser mark), the region irradiated with the laser light is generally melted to form a concave portion as a mark. However, when laser light 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 heated and melted by the irradiation of the laser light to form a concave portion, heat accumulation occurs in the irradiation region of the laser light and the surroundings thereof. Since this heat accumulation causes strain on the surface of the flat glass, it is a cause of a decrease in strength. Further, since the molten portion flows around and remains, it is difficult to form a groove having a correct shape and size in accordance with the movement trajectory of the pulsed laser in the irradiation region.

In this regard, in the present invention, the annular groove is formed by irradiation and ablation of the laser light, and the glass in the laser light irradiation region disappears due to vaporization. Further, in order to form the ablation, it is possible to irradiate the laser light of a high energy density in a very short period of time, and it is possible to suppress the occurrence of heat accumulation in the irradiation region of the laser light and the surroundings. Therefore, the groove can be formed while suppressing the occurrence of thermal strain, and the intensity of the irradiation region of the laser light can be ensured. Further, by forming a groove by ablation, in order to reduce the flow amount of the molten glass, it is possible to form a groove having a correct shape and size by emulating the movement locus of the irradiation region of the laser light.

Further, in this case, in the method of forming the message display portion of the present invention, the annular groove may be formed by scanning the laser light in a ring shape.

Further, in the method of forming a message display portion of the present invention, the laser light is a pulsed laser, and the pulse width used may be a picosecond to femtosecond level.

For example, using a nanosecond laser that is generally used (the pulse width is The pulse laser of the nanosecond level forms such a mark, and if the irradiation condition is precisely controlled, although the ablation occurs in the irradiation area of the laser light, in this case, a large amount of glass is melted. On the other hand, if a pulsed laser with a pulse width of picoseconds to femtoseconds (so-called picosecond laser or femtosecond laser) is used, since the pulse width is very short, heat accumulation does not occur in the glass. The ablation is formed only in the irradiation region of the laser light (the glass is substantially not melted around the irradiation region of the laser light). Therefore, it is possible to surely prevent the occurrence of thermal strain and to ensure the strength more stably. Further, since it is possible to prevent the glass from flowing and to flow around, it is possible to form a groove only in the irradiation region of the laser light, and it is expected that the shape accuracy and dimensional accuracy of the groove are improved. In addition, in the case of a picosecond laser and a femtosecond laser, it is not necessary to consider the flow of the molten glass like a nanosecond laser, and the control can be simplified because the irradiation conditions of the laser light can be set.

As described above, according to the present invention, it is possible to form a highly recognizable information display portion on the surface without lowering the strength of the flat glass.

1‧‧‧ flat glass

1a‧‧‧around parts

2‧‧‧ surface

2a, 2b‧‧‧ divided areas

3‧‧‧Information Display Department

4‧‧‧Deficit

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 reflecting surface

15‧‧‧ lens

16‧‧‧Support desk

17, 18‧‧‧ scan motor

A1‧‧‧field of exposure

Scanning trajectory of L1‧‧‧ laser

Fig. 1 is a plan view showing a sheet glass according to an embodiment of the present invention.

Fig. 2 is an enlarged view of a principal part of the flat glass shown in Fig. 1.

Fig. 3 is an enlarged view of a portion A of the flat glass shown in Fig. 2;

Fig. 4 is an enlarged view of a portion B of the flat glass shown in Fig. 3;

Fig. 5 is a cross-sectional view taken along line C-C of the flat glass shown in Fig. 4.

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

Fig. 7A is an enlarged plan view showing a principal part of a method of forming an annular groove by using the laser marking device shown in Fig. 6.

Fig. 7B is an enlarged plan view showing the principal part of a method of forming an annular groove by the laser marking device shown in Fig. 6.

Fig. 7C is an enlarged plan view showing the principal part of a method of forming an annular groove by the laser marking device shown in Fig. 6.

[Embodiment]

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

Fig. 1 is a plan view showing a sheet glass 1 according to an embodiment of the present invention. The plate glass 1 can be used, for example, as a semiconductor supporting substrate. As shown in FIG. 1, the message display portion 3 is formed on the surface 2 of the flat glass 1. In the present embodiment, the flat glass 1 has a substantially circular plate shape. Further, the peripheral portion 1a of the sheet 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.

Further, the flat glass 1 is preferably in the form of a wafer (slightly rounded), and in this case, the diameter is set to 100 mm or more and 500 mm or less, preferably 150 mm or more and 450 mm or less. If using this shape The size of the flat glass 1 is more suitable for the manufacturing process of a semiconductor package.

Further, in the above application, the thickness of the sheet 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 below 0.9mm. The smaller the plate thickness, the smaller the quality of the laminate included in the flat glass 1, and the handleability of the laminate can be improved. On the other hand, if the thickness of the sheet is too small, the strength of the flat glass 1 itself may be lowered, and there is a problem that the function as a support plate cannot be exhibited. Therefore, the thickness of the flat glass 1 is set to 0.1 mm or more, preferably 0.2 mm or more, more preferably 0.3 mm or more, still more preferably 0.4 mm or more, still more preferably 0.5 mm, and particularly preferably 0.6mm or more, preferably 0.7mm or more.

The message display unit 3 is shown in an enlarged manner in the portion A in FIG. 2, and is composed of, for example, a plurality of characters 5 (the characters 5 referred to herein include at least the ideograms such as the numbers shown in FIG. 2). Further, each character 5 is composed of a plurality of points 6 as shown in FIG.

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

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

Next, the size of the annular groove 7 will be 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, 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 grooves 7 and 7 adjacent to each other is set to, for example, 0.06 mm or more and 0.25 mm or less, preferably 0.10 mm or more and 0.16 mm or less. Further, at this time, the mutually adjacent grooves 7 and 7 are set to be larger than the outer diameter d1 of the groove 7 by the distance d4 between the centers C1 and C2 of the adjacent grooves 7 and 7 in order to prevent mutual interference therebetween. Still bigger. Specifically, the interval d5 between the adjacent grooves 7 and 7 is set to 0.10 mm or more, preferably 0.20 mm or more. The above dimensions are defined from the viewpoint of satisfying the visibility of the point 6, the strength of the sheet glass 1, and particularly the strength of the region where the dots 6 are formed.

Further, as in the present embodiment, the surface 2 of the sheet glass 1 has a disk shape, and when the missing portion 4 as the positioning portion is provided in the peripheral portion 1a (Fig. 1), when the circumferential center position C3 of the missing portion 4 is Benchmark In this case, the phase angle θ ( FIG. 2 ) of C3 and the circumferential center position C4 of the message display unit 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 the character 5 having the dot 6 as a constituent unit and the message display portion 3 formed by combining the plural characters 5 are provided on the surface 2 of the flat glass 1, the dot 6 is 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) remains. Therefore, the volume of the concave portion (annular groove 7) of the present invention is greatly reduced as compared with the concave portion of the conventional shape (slightly cylindrical shape) having the same outer diameter d1. Therefore, it is possible to prevent the strength of the region where the information display portion 3 is provided in the sheet glass 1 from being lowered. Further, in the case of the annular groove 7, as long as the outer diameter d1 is not changed, the visibility is not greatly lowered even if the width w of the groove 7 is lowered. Therefore, if the width w is lowered without changing the outer diameter d1 of the groove 7, the volume of the region inside 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 method of laser light. More detailed below.

Fig. 6 is a view showing an example of the configuration of a laser marking device 10 according to an embodiment of the present invention. As shown, the laser marking device 10 includes a laser oscillator 12 that oscillates a pulsed laser 11 having a predetermined pulse width, and two-dimensional illumination that controls a pulsed laser 11 oscillated from the laser oscillator 12. The first scanning mirror 13 and the second scanning mirror 14 at the position, and the pulsed laser 11 controlled by the first and second scanning mirrors 13, 14 collect the lens 15 at the two-dimensional irradiation position.

Therefore, at this time, the pulsed laser 11 oscillated from the laser oscillator 12 is reflected by the first laser reflecting surface 13a of the first scanning mirror 13, and the reflected pulsed laser 11 is reflected by the second scanning. The second laser reflecting surface 14a of the mirror 14 is reflected by the lens 15, and illuminates a predetermined portion of the sheet glass 1 supported on the support table 16, that is, the region where the information display portion 3 is formed is irradiated with the pulsed laser 11. Further, at this time, the first scanner motor 17 connected to the first scanning mirror 13 is slewingly driven, the phase of the first laser reflecting surface 13a of the first scanning mirror 13 is adjusted, and the second scanning mirror 14 is rotatably driven. The second scanner motor 18 adjusts the phase of the second laser reflection surface 14a of the second scanning mirror 14 to set the scanning locus L1 of the pulse laser 11 that illuminates the surface 2 of the sheet glass 1 (see FIGS. 7A to 7C described later). ).

Further, 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 10 fs or more and 500000 fs (500 ps) or less. Further, 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 be 1 Hz or more and 1 G (giga) Hz or less. Further, 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 locus 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 in the laser marking device 10 having the above configuration and the character 5 having the point 6 as a component (the message display portion 3) will be described. The method of formation.

First, as shown in FIG. 7A, scanning is started along the scanning trajectory L1 of the pulse laser 11 while the pulse laser 11 is irradiated to the scanning start point P0 on the predetermined scanning trajectory L1. By this irradiation operation, ablation is formed in the irradiation area A1 of the pulsed laser 11, whereby the scanning start point P0 is used as a starting point, and a groove is formed along the scanning track L1 area at a predetermined width w according to the outer diameter size of the irradiation area A1. 7 (Fig. 4, Fig. 7B).

Next, the scanning trajectory L1 is slightly wound one round, and when the irradiation center of the pulse laser 11 returns to the scanning starting point P0, the scanning and irradiation of the pulse laser 11 are stopped. Thereby, the ring shape is closed along the scanning locus L1, and in the present embodiment, the annular groove 7 is completed (FIG. 7C).

By this method, after forming one dot 6, the focus of the laser 11 is then moved in a predetermined formation region of the adjacent dot 6, and the pulse laser 11 is irradiated by the pattern shown in FIGS. 7A to 7C. Irradiation causes erosion and forms an annular groove 7 constituting the point 6. By repeating the irradiation operation of the pair of predetermined formation regions constituting all the dots 6 of one character 5, the corresponding complex point 6 is formed by forming a single character 5 with the plurality of dots 6 as a constituent unit (FIG. 2). .

Then, the predetermined formation area of the other character 5 is repeated as described above, and the plural character 5 forming the message display unit 3 is formed by the corresponding complex point 6 (FIG. 2, FIG. 3).

By this method, in the present invention, since the annular groove 7 constituting each of the dots 6 is formed by the ablation by the irradiation of the pulsed laser 11, the glass of the irradiation region of the pulsed laser 11 (that is, the irradiation region A1) gasification And disappeared. Further, in order to form the ablation, the pulse laser 11 having a high energy density is irradiated in a very short period of time, and heat accumulation in the irradiation region A1 of the pulse laser 11 and the surroundings can be suppressed. Therefore, the groove 7 can be formed while suppressing the occurrence of thermal strain, and the intensity of the irradiation region A1 of the pulsed laser 11 can be ensured. Further, by forming the groove 7 by the ablation, in order to greatly reduce the flow of the molten glass around, the groove 7 having the correct shape and size can be formed by emulating the movement locus (scanning locus L1) of the irradiation area A1 of the pulsed laser 11.

Further, in the present embodiment, as the pulse laser 11, a pulse laser having a pulse width of picosecond to femtosecond level (so-called picosecond laser or femtosecond laser) is used. When such a type of laser light is used, the characteristic that the pulse width is extremely short can be utilized, and in the case where the sheet glass 1 does not generate heat accumulation, only the ablation is formed in the irradiation area A1 of the pulsed laser 11. Then, it is possible to surely prevent the occurrence of thermal strain and ensure a more stable flat glass 1 strength. Further, 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. In the present embodiment, in the surface 2 of the sheet glass 1, the first divided region 2a defined by the annular groove 7 on the inner side and the second divided region defined on the outer side of the annular groove 7 are formed. 2b, which is formed on the same plane in a flat manner, has good visibility. In addition, in the case of a picosecond laser and a femtosecond laser, it is not necessary to consider the flow of the molten glass as in the case of a nanosecond laser, and the control of the pulsed laser 11 can be set, and the control can be simplified.

Further, as in the present embodiment, when the annular groove 7 is formed by the irradiation of the pulsed laser 11, the irradiation energy deviation of the pulsed laser 11 can be suppressed as compared with the case where the groove 7 has a polygonal shape such as a substantially rectangular shape ( Photo Shooting time deviation). Thereby, the groove 7 controlled to have a high-precision shape and size can be formed. Of course, if the shape accuracy and the dimensional accuracy are higher, the defect portion in the strength is less, and the strength can be further improved.

Although the above description of an embodiment of the present invention has been made, the method of forming 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 an annular shape (FIG. 4), but the shape is not limited to this. For example, although not shown in the drawings, a polygonal shape such as a slightly rectangular shape or the like may be formed to form a non-annular groove 7. Alternatively, the groove 7 is formed in a point symmetrical shape with respect to the center (center of gravity) of the groove 7 such as a polygon or a meandering pattern.

Further, in the above-described embodiment, as shown in FIG. 4 and the like, the annular groove 7 is formed in a completely closed state, but the present invention is not necessarily limited to this embodiment. The annular groove 7 may be formed in a form of a part of the opening, for example, in a C-shape or the like without causing an identification problem. When such a groove 7 is formed, for example, in the case where the annular groove 7 is formed by irradiating the pulsed laser 11 in the above-described manner, the irradiation area A1 is repeated due to the scanning of the pulsed laser 11, and the overlapping portion can be prevented. The shape of the groove 7 or the deviation of the width w.

Further, in the above-described 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 not shown in the drawings, as a purpose of further improving the visibility, a dot-shaped recess may be formed in the center of the annular groove 7 forming the outer contour of the dot 6 (in the case of the first divided region 2a in FIG. 4). . Or at the point of formation 6 The inner side of the annular groove 7 of the outer contour may be formed by one annular groove.

Further, in the above embodiment, the pulse laser 11 that irradiates and scans one beam in the above-described embodiment is exemplified in the case where only one annular groove 7 is formed in the irradiation and scanning region. However, in order to improve the work efficiency, the annular groove 7 constituting the point 6 may be formed at the same time. In this case, for example, although not shown in the drawings, the pulsed laser 11 is split by a conventional spectroscopic means such as one or a plurality of beam splitters or spatial light phase modulators, and the pulsed light is split by the light. The shots 11 are illuminated and scanned at predetermined formation areas of the respective corresponding points 6, and a plurality of grooves 7 (i.e., a plurality of points 6) can be simultaneously formed (once).

Further, in the above-described embodiment, the form in which the pulsed laser 11 is scanned by the laser marking device 10 is exemplified as a means for forming the annular groove 7 constituting the point 6, but the present invention is not necessarily limited to this embodiment. For example, although the illustration is omitted, a predetermined mask is irradiated with a laser, and by irradiating the object (flat glass 1) with the laser beam transmitted through the mask, the shape of the transmission pattern formed in advance in the mask can be formed to form the annular groove 7 . .

In the above description, the present invention exemplifies that the missing portion 4 is formed in the peripheral portion 1a of the surface 2 of the flat glass 1. However, the positioning portion is provided to the peripheral portion 1a of the flat glass 1 other than the missing portion 4, and is also applicable to the present invention. Of course, when the message display portion 3 having the dot 6 as a constituent unit is formed on the surface 2 of the sheet glass 1, the positioning portion is not formed, and the present invention is also applicable.

2‧‧‧ surface

2a, 2b‧‧‧ divided areas

6 o'clock

7‧‧‧ annular groove

Claims (14)

A flat glass provided with a message display portion having a dot as a unit on a surface thereof, wherein the flat glass is formed by an annular groove. The flat glass of claim 1, wherein the groove is annular. The sheet glass according to 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 sheet glass according to any one of claims 1 to 2, wherein an inner diameter of the groove forming the point is 0.035 mm or more and 0.14 mm or less. The sheet glass according to any one of claims 1 to 2, wherein a depth of the groove forming the point is 2.0 μm or more and 30 μm or less. The sheet glass according to any one of claims 1 to 2, wherein, on the surface, a region defined by the groove into the inside of the groove is on the same plane as a region defined by the groove as the outside of the groove. The sheet glass according to any one of claims 1 to 2, wherein a center-to-center spacing of the adjacent points is 0.06 mm or more and 0.25 mm or less. The sheet glass according to any one of claims 1 to 2, wherein the sheet glass has a disk shape and is provided with a positioning portion at a peripheral portion thereof; a central position of the information display portion in the circumferential direction is in a circumferential direction of the positioning portion The center position is set in the range of 2° or more and 10° or less in the circumferential direction as a reference. The sheet glass according to any one of claims 1 to 2, wherein the information display unit has one or more elements selected from the group consisting of: a character, a symbol, a two-dimensional code, and a graphic; and the plurality of points constitute the aforementioned 1 kind The elements on it. The flat glass according to any one of claims 1 to 2, wherein the information display unit is selected from the group consisting of a size, a linear expansion ratio, a batch size, a partial thickness ratio, a manufacturer name, a seller name, and a material of the flat glass. At least one of the messages in the code. A method of forming a message display portion is a method of forming a message display portion on a surface of a flat glass, wherein the information display portion has a dot as a constituent unit; and the dot is formed by an annular groove. A method of forming a message display portion according to claim 11, wherein the annular groove is formed by ablation by irradiating laser light. The method of forming a message display unit according to claim 12, wherein the annular groove is formed by scanning the laser light in a ring shape. A method of forming a message display portion according to claim 12 or 13, wherein said laser light is a pulsed laser, and a pulse width used is a picosecond to femtosecond level.