JP7679688B2 - Glass Materials - Google Patents

Description

The present invention relates to a glass member.

For the purpose of managing the manufacturing process of glass components, glass components are known that have marks formed on their surfaces that are made up of a combination of letters, symbols, figures, etc., from which various information about the glass components can be obtained.

As an example of a glass member having such a mark, there is disclosed a plate glass having an information display portion on its surface, the constituent units of which are dots formed in annular grooves (see, for example, Patent Document 1). In the plate glass of Patent Document 1, the mark is formed by irradiating the surface of the glass member with a laser, causing the glass to disappear and creating dots in the laser irradiated area.

An optical cover glass has also been disclosed that has a flat plate portion and a frame portion, and a recess surrounded by the flat plate portion and the frame portion is formed by wet etching (see, for example, Patent Document 2).

JP 2016-210644 A JP 2011-37694 A

However, when irradiating the surface of a glass member with laser light to process a mark, as in the technology described in Patent Document 1, the mark is formed by vaporizing the glass by irradiating the glass plate with high-energy density laser light for a very short period of time. This can easily cause many tiny cracks to form at the boundary between the laser-processed area and the non-processed area, making the outline of the mark unclear.

In addition, when processing recesses by etching, as in the technology described in Patent Document 2, the angle of the boundary between the etched and unetched areas tends to be gentle, which can make the outline of the mark unclear.

When a mark provided on the surface of a glass member is used to position the glass member, the visibility of the mark affects the accuracy of the positioning. For example, when a glass member is positioned using an optical device that uses a camera and then processed, if the outline of the mark is unclear, the glass member cannot be positioned accurately, and it may not be possible to process the glass member or form the printing layer with high accuracy.

One aspect of the present invention aims to provide a glass member having a recess with excellent visibility.

One aspect of the glass member according to the present invention is a glass member having a recess, in which the angle between the main surface of the glass member and the opening end surface of the recess is 90° to 130° in a cross-sectional view.

One aspect of the present invention is to provide a glass member having a recess with excellent visibility.

FIG. 2 is a plan view of a glass member according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II of FIG. FIG. 2 is an enlarged view of the recess in FIG. 1 . This is a cross-sectional view of FIG. 3 taken along line II-II. FIG. 5 is a partially enlarged view of FIG. 4 . 3 is a flowchart showing a method for manufacturing a glass member. 1 is a SEM photograph of a surface including a recess of the glass member of Example 1-1. 1 is a SEM photograph of a cross section including a recess of the glass member of Example 1-1. FIG. 9 is a partially enlarged view of FIG. 8 . 1 is a SEM photograph of a surface including a recess of the glass member of Example 1-3. 1 is a SEM photograph of a cross section including a recess of the glass member of Example 1-3. FIG. 12 is a partially enlarged view of FIG. 1 is a SEM photograph of a surface including a recess of the glass member of Example 1-5. 1 is a SEM photograph of a cross section including a recess of the glass member of Example 1-5. 1 is a SEM photograph of a surface including a recess of the glass member of Example 3-1. 1 is a SEM photograph of a surface including a recess of the glass member of Example 3-2.

The following is a detailed description of an embodiment of the present invention. To facilitate understanding of the description, the same components in each drawing are given the same reference numerals, and duplicate descriptions are omitted. The scale of each member in the drawings may differ from the actual scale. In this specification, a tilde "~" indicating a numerical range means that the numerical values before and after it are included as the lower and upper limits, unless otherwise specified.

<Glass components>
A glass member according to an embodiment of the present invention will be described. Fig. 1 is a plan view of the glass member according to this embodiment, and Fig. 2 is a cross-sectional view taken along line I-I of Fig. 1. As shown in Figs. 1 and 2, the glass member 1 according to this embodiment is a plate-like member having a recess 10 and a printed layer 20 on its main surface 1a, the main surface 1a being flat, and the recess 10 being used as a mark for positioning the glass member 1. The glass member 1 may be formed in a curved shape.

The external shape of the glass member 1 in plan view is not particularly limited, and may include straight and curved parts, or may be composed of only curved parts such as a circle or an ellipse. For example, the glass member 1 is formed in a substantially rectangular shape with rounded corners C1 to C4 in plan view, and the rounded corners C1 to C4 have different curvatures. The main surface 1a is the front surface (upper surface) of the glass member 1, and the surface opposite the main surface 1a is the back surface (lower surface) of the glass member 1. The curvatures of the corners C1 to C4 may all be the same, or at least one of the four corners C1 to C4 may be different. The number of rounded corners may be three or more in plan view of the glass member 1.

In this embodiment, the recess 10 of the glass member 1 can be used as a mark for positioning the glass member 1, so that the outer shape of the glass member 1 does not have to have straight line portions that are parallel or perpendicular to each other in a plan view. Furthermore, the outer shape of the glass member 1 does not have to have straight line portions in a plan view. In other words, the glass member 1 can be configured not to have two straight line portions that are perpendicular to each other in a plan view.

The end faces of the glass member 1 may be formed substantially perpendicular to the ends of the main surface 1a and the back surface, or may be formed at an angle.

Examples of the glass member 1 include a glass wafer (glass substrate), a glass panel, a glass lens, etc. Examples of the material that can be used for the glass member 1 include soda-lime silica glass, borosilicate glass, aluminosilicate glass, etc.

The glass member 1 may be physically strengthened or chemically strengthened. When chemically strengthening, ions with a small ionic radius, such as Li ions and Na ions, contained in the surface of the glass member 1 are replaced with ions with a relatively large ionic radius, such as K ions. This forms a compressive stress layer at a predetermined depth from the surface of the glass member 1. By chemically strengthening the glass member 1 and forming a compressive stress layer on the surface of the glass member 1, the strength of the glass member 1 can be improved and damage to the glass member 1 due to contact, etc. can be suppressed.

As shown in FIG. 1, two recesses 10 are formed near different end faces of the main surface 1a of the glass member 1. The recesses 10 are formed as annular grooves in the main surface 1a. FIG. 3 is an enlarged view of the recesses 10 in FIG. 1, and FIG. 4 is a cross-sectional view taken along line II-II in FIG. 3. As shown in FIG. 3, the recesses 10 are formed as annular grooves in the main surface 1a in a plan view, and as shown in FIG. 4, the recesses 10 form grooves in a cross-sectional view.

The recess 10 may be a circular recess, an elliptical groove, an elliptical recess, etc., in which the contour between the recess 10 and the main surface 1a of the glass member 1 in a planar view is curved. Also, the recess 10 may be a polygonal groove, a polygonal recess, a cross-shaped groove, etc., in which the contour between the recess 10 and the main surface 1a of the glass member 1 in a planar view is linear. Furthermore, the recess 10 may be a curved and linear contour, in which the contour between the recess 10 and the main surface 1a of the glass member 1 in a planar view is curved and linear.

In addition to the shapes described above, the recess 10 may also form symbols, character strings, bar codes, two-dimensional codes, etc.

The number of recesses 10 formed on the main surface 1a of the glass member 1 may be one or may be three or more.

The recess 10 may be formed on both the main surface 1a of the glass member 1 and the main surface opposite the main surface 1a.

Figure 5 is a partially enlarged view of Figure 4. As shown in Figure 5, the side surface 11 (wall surface) of the recess 10 has an opening end surface 111, an intermediate side surface 112, and a bottom side surface 113.

As shown in FIG. 5, when the depth H0 (see FIG. 4) of the recess 10 is taken as 100%, the opening end surface 111 is the side surface between the position 11a (5% depth recess position) of the side surface 11 of the recess 10 at a depth H1 of 5% in the vertical direction from the main surface 1a of the recess 10 with respect to the depth H0 (see FIG. 4) of the recess 10, and the main surface 1a.

The depth H0 of the recess 10 is the distance from the main surface 1a of the glass member 1 to the deepest part of the bottom of the recess 10 in a cross-sectional view, i.e., the maximum depth of the bottom surface 12 of the recess 10.

As shown in FIG. 4, when the depth H0 of the recess 10 is taken as 100%, the intermediate side 112 is between a recess position 11a that is 5% deeper from the main surface 1a in the vertical direction with respect to the depth H0 of the recess 10, and a position (50% deeper recess position) 11b of the side 11 of the recess 10 at a depth H2 that is 50% deeper from the main surface 1a in the vertical direction with respect to the depth H0 of the recess 10.

The bottom side 113 is the side between the intermediate side 112 and the bottom side 12, as shown in FIG. 4.

As shown in FIG. 5, in a cross-sectional view of the recess 10, the angle α between the main surface 1a of the glass member 1 (main surface of the glass member) and the opening end surface 111 of the recess 10 is 90° to 130°. The angle α is preferably 92° to 120°, more preferably 95° to 115°, and even more preferably 100° to 110°. If the angle α is 90° to 130°, the boundary between the recess 10 and the main surface 1a is clear, and the outline of the recess 10 can be made clear. In addition, because the angle α is a moderate inclination, the cost required for forming the recess 10 can be reduced.

The angle α of the opening end surface 111 refers to the angle between the main surface 1a and a straight line drawn from the 5% depth recess position 11a toward the main surface 1a along the shape of the recess 10. If the 5% depth recess position 11a is a curve, the angle α of the opening end surface 111 is the angle between the tangent at the 5% depth recess position 11a and the main surface 1a.

Of the side surfaces 11 closer to the bottom surface 12 than the opening end surface 111, it is preferable that the middle side surface 112 has an angle β of 90° to 130° with respect to the main surface 1a of the glass member 1 in a cross-sectional view. The angle β is more preferably 92° to 120°, even more preferably 95° to 115°, and most preferably 100° to 110°. If the angle β is 90° to 130°, the angle β can be set close to the angle α, so that the change in the inclination of the side surface 11 of the recess 10 can be suppressed. This makes it possible to prevent the boundary between the recess 10 and the main surface 1a from becoming unclear.

The angle β of the intermediate side surface 112 refers to the angle between the main surface 1a and the straight line connecting the 5% depth recess position 11a and the 50% depth recess position 11b.

In addition, the circularity of the outer shape of the recess 10 in plan view is preferably 5% or less of the outer dimensions, more preferably 3% or less, and even more preferably 1% or less. If the circularity of the outer shape of the recess 10 is 5% or less of the outer dimensions, the shape of the recess 10 is clearer, and the outline of the recess 10 can be more clearly identified.

Circularity can be determined based on JIS B0621-1984, Definition and Display of Geometric Deviation.

As shown in FIG. 4, it is preferable that the recess 10 has a curved bottom surface 12. If the bottom surface 12 of the recess 10 has a curved surface, the recess 10 can be easily formed, and since the recess 10 has no corners, it is less likely to lose its shape. In addition, when bending stress or the like is applied to the glass member 1, cracks caused by the recess 10 can be suppressed.

It is preferable that the surface roughness Rq of the bottom surface 12 is smaller than the surface roughness Rq of the side surface 11 of the recess 10. If the surface roughness Rq of the bottom surface 12 is smaller than the surface roughness Rq of the side surface 11 of the recess 10, the bottom surface 12 can be easily seen from the outside, and therefore the recess 10 can be easily recognized from the outside.

The surface roughness Rq is the root mean square roughness Rq defined in JIS B 0601:2001. This root mean square roughness Rq means the standard deviation of the surface roughness. The surface roughness Rq can be measured using a laser microscope.

The ratio of the depth H0 of the recess 10 to the thickness of the glass member 1 (depth H0 of the recess 10/thickness of the glass member 1) preferably satisfies the following formula (1). That is, the depth H0 of the recess 10/thickness of the glass member 1 is preferably 0.05 to 0.5, more preferably 0.10 to 0.4, and even more preferably 0.15 to 0.25. If the depth of the recess 10/thickness of the glass member 1 is 0.05 to 0.5, the recess 10 can have a sufficient depth to form a groove, and can be recognized from the outside. In addition, the thickness of the glass member 1 can be sufficiently secured relative to the depth of the recess 10, and therefore the strength of the glass member 1 can be maintained high. 0.05<depth H0 of the recess 10/thickness of the glass member 1<0.5 ... (1)

As shown in Figures 1 and 2, the printing layer 20 is provided on the main surface 1a at a position different from the recess 10 in a plan view. The printing layer 20 is, for example, a model symbol, a manufacturing number, a light-shielding layer, etc. If there is a recess 10, it can function as an alignment mark for positioning when forming the printing layer 20. The printing layer 20 can be formed of a colored ink layer such as black ink.

The glass member 1 may also have an AR film, a light-shielding layer, etc. on its main surface 1a.

(Method of Manufacturing Glass Member)
A method for manufacturing the glass member 1 according to this embodiment will now be described. Fig. 6 is a flowchart showing a method for manufacturing the glass member 1 according to this embodiment.

As shown in FIG. 6, in the method for manufacturing a glass member according to this embodiment, first, a raw glass plate is prepared (preparation process of raw glass plate: step S11).

The glass material that can be used to form the glass plate can be, for example, borosilicate glass, soda-lime glass, high silica glass, etc. The size, thickness, shape, etc. of the glass plate can be appropriately selected depending on the application of the finished glass member 1.

The glass plate can be manufactured using known manufacturing methods such as the float method, the downdraw method (e.g., the overflow downdraw method), the redraw method, the press molding method, and the pull-up method. As a manufacturing method for the glass plate, it is preferable to use the float method because of its excellent productivity and cost.

Next, the glass plate is cut into multiple glass substrates (glass plate cutting process: step S12).

Methods for cutting the raw glass plate include, for example, a method of cutting by irradiating the surface of the raw glass plate with laser light and moving the irradiated area of the laser light on the surface of the raw glass plate, and a mechanical cutting method using a cutter wheel, etc.

Next, the glass substrate is processed into the shape described above in plan view, and a recess 10 is formed on the surface of the glass substrate (processing the outer shape of the glass substrate and forming a recess: step S13). The surface of the glass substrate corresponds to the main surface 1a of the glass member 1 shown in Figures 1 and 2, and hereinafter the surface of the glass substrate is referred to as the main surface 1a.

The processing of the outer shape of the glass substrate and the formation of the recess 10 are performed simultaneously, but they may be performed separately. When performed separately, the recess 10 is formed, and then the outer shape is processed using the recess 10 as a reference. In this way, the outer shape can be processed with high precision. In addition, the thickness of the glass substrate may be processed to an appropriate thickness before, after, or simultaneously with the processing of the outer shape of the glass substrate. Methods for processing the thickness of the glass substrate include polishing and slimming (chemical polishing using a chemical solution).

The processing of the glass substrate's contour and other external shapes and the formation of the recesses 10 can be performed by using a combination of laser and wet etching.

As the laser, _CO2 laser, Nd:YAG laser, etc. can be used, and a semiconductor laser pumped YAG laser is preferable because of its good focusing ability. By focusing the laser on the main surface 1a of the glass substrate, a modified region can be formed on the main surface 1a of the glass substrate and below it. In addition, when focusing the laser, it is preferable to use a femtosecond laser because the glass substrate around the laser focusing portion is hardly thermally or chemically damaged.

Wet etching is performed by immersing the glass substrate in an etching solution. It is preferable to use an etching solution that is optimal for the material constituting the glass member 1, and suitable solutions include aqueous solutions containing fluorides such as hydrogen fluoride, ammonium fluoride, potassium fluoride, and sodium fluoride; aqueous solutions containing inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid; and aqueous solutions containing organic acids such as acetic acid and succinic acid. These may be used alone or in combination of two or more.

After forming modified regions by irradiating the outer peripheral surface and specific positions of the main surface 1a of the glass substrate with a laser, the glass member is immersed in an etching solution to perform wet etching. When the glass member is immersed in the etching solution, the etching solution penetrates more easily into the modified regions formed by laser irradiation than into the unmodified regions not irradiated with the laser, and the etching can be promoted more in the modified regions than in the unmodified regions. Therefore, the etching rate of the modified regions is higher than the etching rate of the unmodified regions, and therefore etching can be promoted more in the modified regions than in the unmodified regions.

This allows the glass member 1 to be obtained with an arbitrary contour shape formed along the modified region, and with a generally rectangular shape with rounded corners in a plan view, each corner having a different curvature. A ring-shaped recess 10 can be formed along the modified region at a specific position on the main surface 1a of the glass member 1.

Next, the main surface 1a and the back surface of the glass member 1 are chemically strengthened (chemical strengthening process: step S14).

By chemically strengthening the glass member 1, ions with a small ionic radius, such as Li ions and Na ions, contained in the principal surface 1a and rear surface of the glass member 1 are replaced with ions with a relatively large ionic radius, such as K ions. This forms a strengthened layer to a predetermined depth from the principal surface 1a and rear surface of the glass member 1. By chemically strengthening the glass member 1 and forming a strengthened layer on the principal surface 1a and rear surface of the glass member 1, the strength of the glass member 1 can be improved and damage to the glass member 1 due to contact, etc. can be suppressed.

Next, a printed layer 20 is formed near the end face of the main surface 1a of the glass member 1 (printed layer formation process: step S15).

The printed layer 20 can be formed using a printing method such as spray printing, inkjet printing, screen printing, etc. Among these, screen printing is preferably used because it is easy to form the printed layer 20 into the desired shape while making the average thickness of the printed layer 20 uniform.

This results in a glass member 1 having a printed layer 20 on the main surface 1a.

If necessary, an anti-reflection treatment may be performed by depositing (forming) an AR film or a light-shielding layer on the main surface 1a and/or the back surface of the glass member 1.

In this way, the glass member 1 has a recess 10 on the principal surface 1a, and the recess 10 is formed so that the angle α between the principal surface 1a of the glass member 1 and the opening end surface 111 is 90° to 130° in a cross-sectional view. This allows the glass member 1 to clearly define the boundary between the recess 10 and the principal surface 1a and to clearly define the outline of the recess 10, making it easier to recognize the recess 10 from the outside. Therefore, the glass member 1 can have a recess 10 with excellent visibility.

In addition, by setting the angle α between the main surface 1a and the opening end surface 111 of the glass member 1 to 90° to 130°, the angle α has a moderate inclination, which reduces the burden of forming the recess 10, and therefore reduces the cost required to form the recess 10.

Furthermore, the recess 10 can be formed in the glass member 1 at the same time as the contour shape is processed, so the recess 10 can be formed without increasing the number of processing steps. Therefore, the glass member 1 can be manufactured at reduced cost.

In the cross-sectional view of the recess 10, the glass member 1 has an angle β of 90° to 130° between the side surface 112 closer to the bottom surface 12 than the opening end surface 111 and the intermediate side surface 112 relative to the bottom surface 12 and the main surface 1a of the glass member 1. This makes it possible to suppress the change in the inclination of the side surface 11 of the recess 10 from the opening end surface 111 to the bottom surface 12 side, and to suppress the boundary between the recess 10 and the main surface 1a from becoming unclear, thereby making the outline of the recess 10 clearer. Therefore, the glass member 1 makes the recess 10 easier to recognize, and thus can further improve the visibility of the recess 10.

In the glass member 1, the recess 10 can be formed as a circular groove. This allows the recess 10 to be easily formed on the main surface 1a. Furthermore, by forming the recess 10 in a circular shape, it can be recognized as having a substantially uniform shape in all directions, thereby improving the visibility of the recess 10.

The glass member 1 can have the circularity of the outer shape of the recess 10 in a plan view be 5% or less of the outer dimensions. This allows the outer shape of the recess 10 to be more clearly grasped, making the recess 10 easier to see and thus improving the visibility of the recess 10.

In the glass member 1, the recess 10 may include a linear shape in a plan view. By forming the recess 10 to include a linear shape, the recess 10 can be easily formed on the main surface 1a. In addition, the external shape of the recess 10 can be more clearly grasped, so the visibility of the recess 10 can be further improved. Furthermore, the shape of the bottom surface 12 is less likely to collapse, and the shape of the recess 10 can be stably maintained, so a decrease in the visibility of the recess 10 is suppressed.

The glass member 1 can have a curved surface on the bottom surface 12 of the recess 10. This allows the bottom surface 12 to be formed in a curved shape, so the shape of the bottom surface 12 is less likely to collapse and the shape of the recess 10 can be stably maintained compared to when the recess 10 has a corner between the side surface 11 and the bottom surface 12. Therefore, the glass member 1 can prevent the visibility of the recess 10 from decreasing.

The glass member 1 can have a surface roughness Rq of the bottom surface 12 of the recess 10 smaller than the surface roughness Rq of the side surface 11 of the recess 10. This makes it easier to check the bottom surface 12 from the outside, making the recess 10 easier to recognize and further improving the visibility of the recess 10.

The glass member 1 can have a depth of the recess 10/thickness of the glass member 1 of 0.05 to 0.5. This allows the recess 10 to have a predetermined depth relative to the thickness of the glass member 1 while preventing a decrease in the strength of the glass member 1. Therefore, the glass member 1 can make the recess 10 easier to recognize from the outside while maintaining the strength of the glass member 1.

The glass member 1 can be formed so that its external shape does not have straight line portions that are parallel or perpendicular to each other in a plan view. As a result, even if the external shape of the glass member 1 is difficult to use as a positioning reference, the position of the glass member 1 can be accurately grasped by using the recess 10 as a marker, so that the positioning of the glass member 1 can be performed with high precision.

The glass member 1 can also be formed so that its outer shape does not have any straight lines in a plan view. As a result, even if the outer shape of the glass member 1 is difficult to use as a positioning reference, such as a circle in a plan view, the position of the glass member 1 can be accurately determined by using the recess 10 as a marker, so that the positioning of the glass member 1 can be performed with high precision.

The glass member 1 can have a printed layer 20 at a position different from the recess 10 in a plan view. The glass member 1 can have the recess 10 function as an alignment mark for positioning when forming the printed layer 20, etc., and therefore can improve the positional accuracy of the printed layer 20 formed on the main surface 1a.

In this way, the glass member 1 has a highly visible recess 10, so that the glass member 1 can be positioned easily and accurately even if the glass member 1 is made of irregularly shaped glass. Therefore, the glass member 1 can be suitably used for glass articles that are unlikely to have straight lines in a plan view and tend to include curved surfaces on the surface, such as cover glass and protective glass for imaging devices.

In this embodiment, the glass member 1 may have an alignment portion on the end face, an orientation flat portion formed by cutting out a portion of the outer periphery, etc.

The following examples are provided to further explain the embodiments, but the embodiments are not limited to these examples. Examples 1-1 to 1-4, 2-1 to 2-12, 3-1, and 3-2 are working examples, and Example 1-5 is a comparative example.

<Example 1-1>
[Preparation of Glass Member]
As a glass member, a soda lime glass (AS2 glass, manufactured by AGC) with outer dimensions of 100 mm×100 mm and thickness of 400 μm was prepared, and a laser was irradiated onto the surface of the glass member in an annular shape to form a modified region. After that, the glass member was immersed in an etching solution to etch the surface of the glass member, thereby forming an annular recess on the surface of the glass member.

[Evaluation of recesses]
The surface of the glass member including the recess was observed by SEM. The surface of the glass member including the recess is shown in FIG. 7. The glass member with the recess formed thereon was then embedded in resin. The side surface of the glass member was then polished to expose the cross section of the recess, and the cross section of the recess was observed by SEM. The cross section of the glass member including the recess is shown in FIG. 8, and a partial enlarged view of FIG. 8 is shown in FIG. 9. As shown in FIGS. 7 to 9, the recess was formed as a circular groove, and the contour of the recess and the surface of the glass member could be clearly recognized, and it was confirmed that the visibility of the recess was high. It was also confirmed that the bottom surface of the recess had a curved surface. The results of the visibility of the recess are shown in Table 1. In Table 1, the visibility of the recess is shown based on the following evaluation criteria.
(Evaluation Criteria)
◯: The outline of the recess and the surface of the glass member can be clearly recognized, and the recess is highly visible.
×: The outline between the recess and the surface of the glass member is unclear, and the visibility of the recess is low.

The opening diameter and depth of the recess were measured from the cross-sectional view of the recess shown in Figure 9, and the angle of the opening end face, the angle of the middle side face, the radius of curvature of the bottom face, and the depth of the recess/glass thickness were calculated. Note that the left side of the opening end face angle and the middle side face angle recess is the inner side face of the glass member in the cross-section of the recess, and the right side is the outer side face of the glass member in the cross-section of the recess. The measurement results of the opening diameter, depth, opening end face angle, middle side face angle, and radius of curvature of the bottom face, and the depth of the recess/glass thickness of the recess are shown in Table 1.

The angle of the opening end face is the angle between the surface of the glass member and a straight line drawn from the position of the side of the recess at a depth of 5% from the main surface in a vertical direction relative to the depth of the recess (5% depth recess position) to the surface side of the glass member along the shape of the recess, assuming the depth of the recess to be 100%. The angle of the intermediate side face is the angle between the surface of the glass member and a straight line connecting the 5% depth recess position and the position of the side of the recess at a depth of 50% from the main surface in a vertical direction relative to the depth of the recess (50% depth recess position).

The surface roughness Rq of the recess was measured using a laser microscope (shape measuring laser microscope VK-100, manufactured by Keyence Corporation). The bottom located at the center of the opening of the recess and the curved surface area around it were defined as the bottom surface. The inner side surface of the glass member in the cross section of the recess was defined as the left side surface, and the outer side surface of the glass member in the cross section of the recess was defined as the right side surface. The measurement results of the surface roughness Rq of the bottom surface, left side surface, and right side surface of the recess are shown in Table 1.

<Example 1-2>
In Example 1-1, the procedure was the same as in Example 1-1, except that the recess was formed so that the opening diameter was 110 μm and the depth was 69 μm. The recess was formed as a circular groove as in Example 1-1, and the outline of the recess and the surface of the glass member could be clearly recognized, and it was confirmed that the visibility of the recess was high. It was also confirmed that the bottom surface of the recess had a curved surface. Table 1 shows the results of measuring the opening diameter, depth, angle of the opening end face, angle of the middle side face, and radius of curvature of the bottom surface, as well as the depth of the recess/glass thickness of the recess formed in the glass member, and the evaluation results of visibility.

<Example 1-3>
In Example 1-1, the procedure was the same as in Example 1-1, except that the recess was formed so that the opening diameter was 112 μm and the depth was 93 μm. FIG. 10 shows the surface including the recess of the glass member, FIG. 11 shows a cross section including the recess of the glass member, and FIG. 12 shows a partially enlarged view of FIG. 11. As shown in FIG. 10 to FIG. 12, the recess was formed in a circular groove like in Example 1-1, and the outline of the recess and the surface of the glass member could be clearly recognized, and it was confirmed that the visibility of the recess was high. It was also confirmed that the bottom surface of the recess had a curved surface. Table 1 shows the results of measuring the opening diameter, depth, angle of the opening end face, angle of the middle side face, and radius of curvature of the bottom surface, depth of the recess/glass thickness, and surface roughness Rq of the recess formed in the glass member, as well as the evaluation results of visibility.

<Example 1-4>
In Example 1-1, the procedure was the same as in Example 1-1, except that the recess was formed so that the opening diameter was 112 μm and the depth was 94 μm. The recess was formed as a circular groove as in Example 1-1, and the outline of the recess and the surface of the glass member was clearly recognizable, confirming that the visibility of the recess was high. It was also confirmed that the bottom surface of the recess had a curved surface. Table 1 shows the results of measuring the opening diameter, depth, angle of the opening end face, angle of the middle side face, and radius of curvature of the bottom surface, as well as the depth of the recess/glass thickness of the recess formed in the glass member, and the evaluation results of visibility.

<Example 1-5>
A resist was formed on the surface of a borosilicate glass (FP-1 glass, manufactured by AGC Technoglass) having an outer dimension of 100 mm×100 mm and a thickness of 1.0 mm as a glass member, and the surface was masked with a dry etching to form a rectangular recess (6 mm×5 mm, depth 400 μm) in the glass member. FIG. 13 shows the surface of the glass member including the recess, and FIG. 14 shows a cross section of the glass member including the recess. As shown in FIG. 13 and FIG. 14, the recess forms a gentle side from the main surface of the glass member to the bottom surface of the recess, and the outline between the recess and the surface of the glass member is unclear, and it was confirmed that the visibility of the recess is low. Table 1 shows the results of measuring the depth, the angle of the opening end face, and the angle of the middle side face, and the depth of the recess/glass thickness of the recess formed in the glass member, as well as the evaluation results of the visibility.

As shown in Table 1, in Examples 1-1 to 1-4, the recesses were clearly visible, but in Example 1-5, the recesses were unclear. Therefore, unlike Example 1-5, in Examples 1-1 to 1-4, the angle of the opening end face is set to 124° or less, which allows the outline of the recesses and the surface of the glass member to be clearly recognized, and the recesses have excellent visibility, so it can be said that the recesses can be effectively used as positioning marks.

<Example 2-1 to Example 2-12>
Glass members were prepared in the same manner as in Example 1-1. The glass members of Examples 2-1 to 2-12 had an opening end face angle (average of the left and right sides) in the range of 104° to 125°, and an intermediate side face angle (average of the left and right sides) in the range of 102° to 115°. The outer dimensions and roundness of the recessed portion of the prepared glass members were measured using a CNC image measuring system (NEXIV, manufactured by Nikon Instech Co., Ltd.), and the ratio of the roundness to the outer dimensions was calculated. The outer dimensions of the recessed portion formed in the glass member, the roundness of the recessed portion, and the calculation results of the ratio of the roundness to the outer dimensions are shown in Table 2.

Furthermore, when the surface and cross section of the recess were observed in the same manner as in Example 1-1, it was confirmed that the recess was formed as a circular groove, as in Example 1-1, and the outline between the recess and the surface of the glass member was clearly recognizable, confirming that the visibility of the recess was high. It was also confirmed that the bottom surface of the recess was curved. The visibility evaluation results are shown in Table 2.

As shown in Table 2, the recesses could be clearly confirmed in all of Examples 2-1 to 2-12. Therefore, by setting the ratio of circularity to the outer dimensions to approximately 0.40 or less in Examples 2-1 to 2-12, the outline between the recesses and the surface of the glass member could be clearly recognized, and the recesses had excellent visibility, so they can be effectively used as positioning marks.

<Example 3-1 and Example 3-2>
Glass members were produced in the same manner as in Example 1-1. The surface including the recess of the glass member of Example 3-1 is shown in FIG. 15, and the surface including the recess of the glass member of Example 3-2 is shown in FIG. 16. As shown in FIG. 15, it was confirmed that a symbol consisting of annular grooves and straight lines was formed in the glass member of Example 3-1. Also, as shown in FIG. 16, it was confirmed that a matrix-type two-dimensional code in which a plurality of circular depressions were arranged was formed in the glass member of Example 3-2.

Therefore, in Examples 3-1 and 3-2, the outline between the recess and the main surface of the glass member is clearly recognizable, and the recess has excellent visibility, so it can be said that they can be effectively used as identification symbols.

Although the embodiments have been described above, they are presented as examples, and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their variations are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

1 Glass member 1a Main surface (front surface)
REFERENCE SIGNS LIST 10 Recess 11 Side surface 111 Open end surface 112 Middle side surface 12 Bottom surface 20 Printing layer

Claims (9)

A glass member having a recess,
an angle between a main surface of the glass member and an opening end surface of the recess is 90° to 130° in a cross-sectional view;
In a cross-sectional view, a side surface of the recess that is closer to a bottom surface than the opening end surface has an angle of 90° to 130° with respect to a main surface of the glass member,
A glass member in which the surface roughness Rq of a bottom surface of the recess is smaller than the surface roughness Rq of a side surface of the recess . The glass member according to claim 1 , wherein the recess is an annular groove or a circular depression. 3. The glass member according to claim 2 , wherein the circularity of the outer shape of the recess in a plan view is 5% or less of the outer dimension. The glass member according to claim 1 , wherein the recess includes a linear shape in a plan view. The glass member according to any one of claims 1 to 4 , wherein the recess has a curved bottom surface. 6. The glass member according to claim 1 , wherein the ratio of the depth of the recess to the thickness of the glass member is 0.05 to 0.5. The glass member according to any one of claims 1 to 6 , wherein the outer shape of the glass member does not have straight line portions that are in a parallel or perpendicular positional relationship with each other in a plan view. The glass member according to claim 7 , wherein the outer shape of the glass member does not include any straight line portions in a plan view. The glass member according to claim 1 , further comprising a printed layer at a position different from the recess in plan view.

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