KR20210113897A - Strengthened glass product and fabricating method of the same - Google Patents

Abstract

The present invention is a tempered glass product including a bent portion, and the bent portion can have a different strengthening depth from an outer side surface and an inner side surface strengthening depth. Accordingly, the tempered glass product of the present application has improved folding characteristics, so that it can be more easily applied to a flexible display device or the like.

Description

STRENGTHENED GLASS PRODUCT AND FABRICATING METHOD OF THE SAME

The present invention relates to a tempered glass product and a manufacturing method thereof, and more particularly, to a tempered glass product used in a touch screen panel and the like and a manufacturing method thereof.

Glass products are treated as essential components in a wide range of technologies and industries such as video and optical equipment such as monitors, cameras, VTRs, mobile phones, transportation equipment such as automobiles, various tableware, and construction facilities, and accordingly, the characteristics of each industrial field Glass having various physical properties has been manufactured and used in accordance with this.

In particular, as a flexible display device has recently been developed, the need for an upper transparent protective film having excellent bending properties and durability has increased. Conventionally, plastic organic materials such as polyester or acrylic have been used as the upper transparent protective film, but these materials have weak mechanical strength and are limited in durability, such as being deformed or damaged by repeated bending. Accordingly, tempered thin glass having excellent heat resistance, mechanical strength and hardness is gradually emerging as a material for an upper transparent protective film for flexible display devices.

However, in the case of tempered thin glass, there is a risk that the tempered thin glass is broken by the compressive stress caused by repeated bending in spite of its excellent strength.

Therefore, there is a need for a study on the tempered thin glass with improved sieve folding durability while maintaining the excellent mechanical strength of the tempered thin glass. Korean Patent No. 10-2011-0049524 discloses a flexible display substrate using chemically tempered glass, but a tempered thin glass for flexible display including a tempered thin glass having excellent folding durability is not disclosed.

Korean Patent Registration No. 10-2011-0049524

One object of the present invention is to provide a tempered glass article having improved mechanical properties and a method of manufacturing the tempered glass article.

1. A tempered glass article comprising a bent portion, wherein the bent portion has a strengthening depth of an outer surface and a strengthening depth of an inner surface different from each other.

2. The tempered glass article according to the above 1, wherein the strengthening depth of the outer surface is 5 to 50% deeper than the strengthening depth of the inner surface.

3. The tempered glass article according to the above 1, wherein the surface compressive stress of the outer surface is 5 to 50% greater than the surface compressive stress of the inner surface.

4. The tempered glass article according to the above 1, wherein the bending angle of the bending portion is 0 to 150°.

5. The tempered glass article according to 1 above, wherein when the bending angle of the bending portion is 0°, the inner radius of the bending portion is 0.1R to 5R.

6. The tempered glass article according to 1 above, comprising two or more bends.

7. The tempered glass article according to 1 above, wherein the thickness of the tempered glass article is 10 to 100 μm.

8. The tempered glass article according to the above 1, wherein the bent portion is formed in a region where a distance from a center line perpendicular to the longitudinal direction with respect to the length of the tempered glass article is 20% or less with respect to the length of the tempered glass article.

9. The tempered glass article according to the above 1, wherein the tempered glass article is used as a protective film for a flexible display.

10. Preparing a preliminary tempered glass by etching the glass original plate; forming a preliminary bend in the preliminary tempered glass; and chemically strengthening the pre-tempered glass including the pre-bend portion through an ion replacement solution.

11. The method of manufacturing a tempered glass product according to the above 10, wherein the preparing of the preliminary tempered glass includes etching both sides or one end of the glass original plate using an etchant.

12. The method of manufacturing a tempered glass article according to the above 10, wherein the forming of the preliminary bending portion forms the preliminary bending portion by applying a physical force to the preliminary tempered glass.

13. The method of manufacturing a tempered glass article according to the above 12, wherein the forming of the preliminary bending portion uses a jig to form the preliminary bending portion.

14. The method of manufacturing a tempered glass product according to the above 13, wherein the chemically strengthening the preliminary tempered glass is chemically strengthened by immersing the pre-tempered glass in the ion substitution solution in a state in which the preliminary tempered glass is fixed to the jig. .

15. The method of manufacturing a tempered glass article according to the above 10, wherein the forming of the preliminary bending portion comprises thermoforming the preliminary tempered glass to form the preliminary bending portion.

16. The method of manufacturing a tempered glass article according to the above 10, wherein the ion displacement solution comprises potassium nitrate (KNO _{3 ).}

Tempered glass articles according to embodiments of the present invention may include a bend. Accordingly, the folding durability of the tempered glass article can be improved.

For example, the tempered glass article may include a bent portion, so that stress added in the process of folding the tempered glass article may be reduced. Accordingly, it is possible to effectively prevent a problem in which the tempered glass product is damaged in the process of repeatedly folding the tempered glass product.

In the tempered glass product according to some embodiments, the strengthening depth of the outer surface of the bent portion may be greater than the strengthening depth of the inner surface. Accordingly, the bent portion can be more easily formed in the tempered glass product.

The method of manufacturing a tempered glass article according to embodiments of the present invention may first form a bent portion before reinforcing the preliminary tempered glass. In addition, it is possible to form a bend in the pre-tempered glass using a jig. Accordingly, it is possible to minimize physical and chemical damage to the tempered glass article that may occur in the process of forming the bent portion in the tempered glass article.

1 is a schematic cross-sectional view showing a tempered glass article according to the present invention.
2 is a schematic schematic diagram for explaining a position where a bent portion is formed.
3 to 7 are schematic cross-sectional views for explaining a method of manufacturing a tempered glass article according to some embodiments.
8 is a schematic diagram illustrating a temperature change in a glass strengthening step according to some embodiments.

Embodiments of the present invention provide a tempered glass article comprising a bend. Accordingly, even when the tempered glass article of the present application is folded, an additional stress that the tempered glass article is subjected to by the folding by the bending portion may be reduced. Accordingly, the tempered glass product can be more easily applied to a flexible display device.

In this specification, the surface compressive stress (Compressive Stress, CS) means the compressive stress in the outermost surface of the glass. The surface compressive stress gradually decreases as it progresses from the surface of the glass to the inside of the glass. In the present specification, the depth of reinforcement (Depth of Layer) may refer to a depth from the surface of the glass to the point at which the compressive stress, which is decreased toward the inside of the glass, becomes substantially zero.

Compressive Stress (CS) and Depth Of Layer can be measured using a surface stress meter (FSM-6000LE).

For example, when the thickness of the glass is about 70 μm or less, the Depth of Layer may be measured using EDAX. For example, by counting the number of atoms from the surface to the center of a glass using EDAX, the depth of layer can be determined based on changes in the concentrations of ^{K +} and Na ^{+ .}

For example, the surface compressive stress (CS) can be measured based on the stress value until the glass breaks while pressing the glass surface with an indenter.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in more detail. However, the following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the above-described content of the present invention, so the present invention is described in such drawings It should not be construed as being limited only to the matters.

1 is a schematic cross-sectional view illustrating a tempered glass article according to exemplary embodiments.

Referring to FIG. 1 , the tempered glass product 100 may include a bent portion 110 . The bent portion 110 may be a region having a bent shape (eg, a U-shape). In this case, in the tempered glass product 100 including the bent portion 110 , the stress added by the bent portion 110 may be reduced even when the tempered glass product 100 is bent or unfolded. Accordingly, the impact received by the tempered glass product 100 in the process of repeatedly folding and unfolding the tempered glass product 100 may be reduced, and the bending durability of the tempered glass product 100 may be improved.

The bent portion 110 is a bent region present in the tempered glass product 100. In the present specification, the concave surface of both surfaces of the bent portion 110 is the inner surface (X), and the convex surface is the outer surface (Y). can be defined as

According to some exemplary embodiments, the reinforcing depth of the outer surface Y and the reinforcing depth of the inner surface X of the bent portion 110 may be different from each other. For example, that the reinforcing depths are different from each other may mean that the difference between the reinforcing depth of the outer surface Y and the reinforcing depth of the inner surface X is about 1 μm or more.

In some exemplary embodiments, the reinforcing depth of the outer surface Y of the bent portion 110 may be about 5 to 50% greater than the reinforcing depth of the inner surface X. In this case, a difference in bending stress may occur between the inner surface X and the outer surface Y due to the difference in the reinforcement depth. In this case, the tempered glass product 100 may be bent such that a concave portion is formed on the inner surface X due to the difference in bending stress. Accordingly, the curved portion 100 may be more easily formed in the tempered glass product 100 .

For example, the difference in the strengthening depth between the outer surface (Y) and the inner surface (X) of the bent portion 10 may be implemented by immersing a preliminary tempered glass to be described later in a bent state in an ion replacement solution.

For example, the tempered glass article 100 adjusts the difference in the tempered depth between the outer surface (Y) and the inner surface (X) of the bent portion 110 to adjust the bending angle and inner radius of the tempered glass article 100 , etc. can be easily adjusted.

According to some exemplary embodiments, in the bent portion 110 , the surface compressive stress of the outer surface Y may be greater than the surface compressive stress of the inner surface X by about 5 to 50%. In this case, a concave portion may be formed in the inner surface X of the tempered glass product 100 due to a difference in surface compressive stress. Accordingly, the bent portion 110 may be more easily formed in the tempered glass article 100 , and thus the folding durability of the tempered glass article 100 may be further improved.

In addition, by adjusting the surface compressive stress difference between the outer surface (Y) and the inner surface (X) of the bent portion 110, it is possible to easily adjust the bending angle and the inner radius of the tempered glass product 100.

According to some exemplary embodiments, the bending angle A of the bent portion 110 may be about 0° to 150°. Referring to FIG. 1 , the bending angle A may refer to an angle formed by meeting each other between regions positioned on both sides of the curved portion 110 and extension lines extending to contact the boundary region of the curved portion 110 , respectively.

For example, when the bending angle A satisfies the above range, additional stress generated in the process of folding the tempered glass product 100 may be reduced. For example, when out of the above range, the tempered glass product 100 may be damaged by stress added in the process of folding the tempered glass product 100 .

According to some exemplary embodiments, when the bending angle of the bent portion 110 is about 0°, the inner radius of the bent portion 110 may be 0.1R to 5R. In the above range, the present tempered glass product 100 can be more easily applied to a flexible display device.

According to some exemplary embodiments, the tempered glass article 100 may include two or more bends 110 . For example, as the tempered glass product 100 includes two or more curved portions 110 , the flexible display device may be folded a plurality of times and in a plurality of directions. Accordingly, the application range of the tempered glass article 100 may be wider.

According to some exemplary embodiments, the thickness of the tempered glass article 100 may be about 10 to 100 μm. In the above range, a thin-film tempered glass product having excellent durability may be implemented. Therefore, the tempered glass product 100 can be easily folded and unfolded, and due to its thin and excellent bending durability, it can be more easily applied to a flexible display device.

When the thickness of the tempered glass product 100 exceeds the above range, the thickness of the glass is thick, there is a problem that it is not easily folded, and if it is less than the above range, the folding durability of the tempered glass product 100 is lowered, and repeated The tempered glass product 100 may be damaged by folding.

2 is a schematic diagram for explaining a position where a bent portion is formed according to some embodiments.

Referring to FIG. 2 , the bent portion formation position (C) is based on the longitudinal direction of the tempered glass product 100, and the distance from the center line (Z) perpendicular to the longitudinal direction is 20 with respect to the length (L) of the tempered glass product % or less. For example, the center line Z is perpendicular to the longitudinal direction and may mean a line that bisects the length of the tempered glass product 100 .

In this case, since the position of the bent portion 110 is not biased to one side, the compressive stress relief effect by the bent portion 110 may be evenly distributed throughout the tempered glass product 100 . Accordingly, it is possible to effectively prevent damage to the tempered glass product 100 due to a relatively large compressive stress continuously acting only in a specific region.

The tempered glass article 100 according to some exemplary embodiments may be used as a protective film for a flexible display. In this case, due to the compressive stress relief effect of the above-described bent portion 110 and the excellent strength of the tempered glass product, the durability and folding durability of the flexible display can be improved at the same time. In addition, unlike the organic protective film, the tempered glass product 100 is not deformed even by repeated bending, so that it is possible to effectively prevent a problem of deterioration in visibility due to deformation of the protective film.

3 to 7 are schematic cross-sectional views for explaining a method of manufacturing a tempered glass article according to exemplary embodiments.

Tempered glass products according to exemplary embodiments prepare a preliminary tempered glass by etching a glass original plate, form a preliminary bend in the preliminary tempered glass, and chemically strengthen the preliminary tempered glass with the preliminary bent portion formed therein through an ion replacement solution. It can be manufactured by

For example, both sides or one side of the glass original plate 80 may be etched using an etching solution.

For example, the etching solution may be an aqueous solution containing hydrofluoric acid. For example, the etchant may comprise about 1 wt% to 20 wt% of hydrofluoric acid, about 0.1 wt% to 5 wt% ammonium fluoride, about 1 wt% to 20 wt% inorganic acid, about 1 wt% to 10 wt% an organic acid or a salt of the organic acid, and a balance of water such that the total weight of the total composition is 100% by weight.

For example, the inorganic acid is sulfuric acid (H ₂ SO ₄ ), hydrochloric acid (HCl), nitric acid (HNO ₃ ), phosphoric acid (H ₃ PO ₄ ), sulfamic acid (SO ₃ HNH ₂ ), perchloric acid (HClO ₄ ), chromic acid (HCrO ₄ ), sulfurous acid (H ₂ SO ₃ ) and nitrous acid (HNO ₂ ) may include at least one selected from the group consisting of.

For example, the organic acid is carboxylic acid, dicarboxylic acid, tricarboxylic acid, tetracarboxylic acid, acetic acid, butanoic acid, citric acid ), formic acid, gluconic acid, glycolic acid, malonic acid, oxalic acid, pentanoic acid, sulfobenzoic acid, sulfobenzoic acid sulfosuccinic acid, sulfophthalic acid, salicylic acid, sulfosalicylic acid, benzoicacid, lactic acid, glyceric acid, succinic acid acid), malic acid, tartaric acid, isocitric acid, propenoic acid, imminodiacetic acid and ethylenediaminetetraacetic acid (EDTA) It may include one or more selected from.

For example, the water may be deionized water having a resistivity of 18 MΩ/cm or more at 25°C.

Referring to FIGS. 3 to 5 , by spraying the etching solution on the glass original plate 80 , both sides or one side of the glass original plate 80 may be etched. For example, the glass original plate 80 is positioned under the etchant spraying device 200 to which the etching solution is sprayed, and then the etching solution is sprayed onto the glass original plate 80 to etch both sides or one side of the glass original plate 80 . can

3 and 4 , the etchant spraying device 200 may include an etchant spraying nozzle 210 , a glass fixing unit 220 , and a spraying body 230 . For example, the etchant injection device 200 may further include a supply unit 240 for supplying the etchant to the injection body 230 .

For example, the glass disk 80 may be inserted into the glass fixing unit 220 of the etchant spraying device 200 . The glass disk 80 inserted into the glass fixing unit 220 may be positioned below the injection body 230 of the etchant injection device 200 . The etchant included in the spray body 230 may be sprayed onto the glass disk 80 through the etchant spray nozzle 210 . Accordingly, both surfaces or a cross-section of the glass original plate 80 may be etched. For example, the etchant may be injected into the injection body 230 through the supply unit 240 .

Referring to FIG. 5 , all of the surface regions 85 located on both surfaces of the glass original plate 80 may be removed by the etching solution sprayed onto the glass original plate 80 . thus. Since the surface state of both surfaces of the glass original plate is formed to be the same, it is possible to implement the tempered glass product 100 having uniform surface properties as a whole.

For example, only one surface of the surface area 85 of the glass original plate 80 may be etched by the etching solution sprayed onto the glass original plate 80 .

In this case, the surface state of both surfaces of the preliminary tempered glass 90 may be adjusted to be different from each other. Accordingly, it is possible to easily implement the tempered glass product 100 having a different reinforcing depth or the surface compressive stress. Accordingly, the tempered glass product 100 including the bent portion 110 may be easily manufactured.

In some exemplary embodiments, surface polishing by ultrasonic waves or an end mill may be performed before etching the glass original plate 80 .

In some exemplary embodiments, a preliminary bending portion may be formed in the preliminary tempered glass 90 on which one or both surfaces of the surface are etched. For example, the preliminary bending portion may be formed by applying a physical force to the preliminary tempered glass 90 .

For example, by applying the physical force to the preliminary tempered glass 90 , the preliminary tempered glass 90 may be bent into a U-shape. For example, the preliminary tempered glass 90 may be fixed in a bent state in a U-shape to form the preliminary bent portion. For example, the preliminary bending portion may mean a region in which the preliminary tempered glass 90 is bent in a U shape.

6 and 7 , the preliminary bent portion may be formed using a jig.

For example, the jig may include a jig body 400 for accommodating the preliminary tempered glass 90 and a support 420 for fixing the preliminary tempered glass 90 accommodated in the jig body 400 .

For example, the preliminary tempered glass 90 may be inserted into the groove region 410 located between the pair of jig bodies 400 . In this case, the support part 420 extending from one end of the jig body 400 may fix both ends of the preliminary tempered glass 90 . Accordingly, it is possible to effectively prevent a problem in which the preliminary tempered glass 90 is damaged in the process of forming the preliminary bent portion by applying a physical force to the preliminary tempered glass 90 .

For example, the preliminary tempered glass 90 fixed to the jig may receive a physical force by movement or shape deformation of the jig. In this case, the preliminary tempered glass 90 is gradually deformed by the jig, and a preliminary bent portion may be formed in the preliminary tempered glass 90 . In this case, a method of applying a physical force to the preliminary tempered glass 90 using the jig may not be particularly limited.

In some exemplary embodiments, the preliminary bending portion may be formed by thermoforming the preliminary tempered glass 90 .

For example, the pre-bent portion increases the internal temperature of the pre-tempered glass 90 to a temperature at which the pre-tempered glass 90 can be molded (eg, glass transition temperature), and then the pre-tempered glass 90 is molded by can be formed.

For example, after inserting the preliminary tempered glass 90 into the mold in which the shape of the preliminary bending part is formed, the temperature inside the mold is set to a temperature at which the preliminary tempered glass 90 can be molded (eg, glass). transition temperature). For example, the molding temperature may be 400 to 600 ℃.

For example, the preliminary tempered glass 90 may include two or more preliminary bends. When the preliminary tempered glass 90 includes a plurality of preliminary bends, positions at which the plurality of preliminary bends are formed may be appropriately changed within a range capable of preventing breakage and damage of the preliminary tempered glass 90 .

For example, the plurality of preliminary bending parts may include a concave preliminary bending part and a convex preliminary bending part. For example, the concave preliminary curved portion may mean a curved portion having a concave inner surface (X), and the convex preliminary curved portion may indicate a convex curved portion of the inner surface (X).

For example, the concave preliminary bending portion and the convex preliminary bending portion may be alternately formed in the preliminary tempered glass 90 .

For example, the preliminary tempered glass 90 may have various shapes by including the concave preliminary bending portion and the convex preliminary bending portion. For example, the preliminary tempered glass 90 may have an S-shape or a W-shape due to the plurality of preliminary bends. Accordingly, the range of the flexible display device to which the tempered glass product 100 can be applied can be expanded.

For example, the pre-strengthened glass 90 having the pre-bent portion formed thereon may be immersed in the ion replacement solution 310 . Thereafter, the pre-tempered glass 90 may be strengthened with the glass-reinforced product 100 . For example, the pre-strengthened glass 90 having the pre-bent portion formed thereon may be immersed in the tempering tank 300 including the ion replacement solution 310 and then subjected to strengthening treatment.

For example, the ion displacement solution may be _{potassium nitrate (KNO 3 ).}

According to exemplary embodiments, in the strengthening of the preliminary tempered glass 90, the preliminary tempered glass 90 is preheated, the preliminary tempered glass 90 is immersed in a high temperature ion replacement solution 310 to be strengthened, and then to room temperature. It can be carried out by cooling slowly. Accordingly, in the tempered glass product 100 , the surface compressive stress (CS) present on the reinforced surface may be increased.

In this case, as the preliminary tempered glass 90 includes the preliminary bent portion, there is a difference in the area and area in which the ion replacement solution 310 contacts between the inner surface and the outer surface of the preliminary bent portion, so the inner surface and the Differences in the degree of reinforcement between the outer surfaces may occur.

Due to this, the strengthening depth or surface compressive stress difference between the inner surface (X) and the outer surface (Y) of the tempered glass article 100 may be generated. For example, the tempered glass article 100 including the bent portion 110 may be manufactured due to the difference in the depth of strengthening or the surface compressive stress between the inner surface X and the outer surface Y, and the like.

FIG. 7 is a schematic model view of the pre-strengthened glass 90 having the bent portion of the strengthening tank 300 immersed in the ion replacement solution 310 observed from the upper side of the strengthening tank 300 .

Referring to FIG. 7 , the preliminary bending part may be formed in the preliminary tempered glass 90 by the jig including the jig body 400 and the support part 420 . The preliminary tempered glass 90 including the preliminary bent portion may be chemically strengthened by being immersed in the ion replacement solution 310 included in the tempering tank 300 together with the jig.

In this case, as the bending by the physical force of the jig and the bending by the chemical strengthening of the ion replacement solution 310 are simultaneously performed, the tempered glass product 100 including the bent portion 110 can be manufactured more easily. can In addition, the inner radius of the bent portion 110 may be further reduced.

For example, a plurality of preliminary tempered glass 90 included as the preliminary bending portion may be simultaneously inserted into the tempering tank 300 . For example, the inserted plurality of preliminary tempered glass 90 may be sequentially inserted into the upper side of the tempering tank 300 in parallel to each other.

8 is a graph illustrating a temperature change in a glass strengthening process according to example embodiments.

Referring to FIG. 8 , the preliminary tempered glass 90 may be started at room temperature and gradually increased to T1, which is the preheating end temperature. Accordingly, due to a sudden temperature difference between the preliminary tempered glass 90 and the ion replacement solution 310 , it is possible to effectively prevent a problem in which the preliminary tempered glass 90 is damaged.

For example, the preheating end temperature T1 may be greater than or equal to the melting point of the ion replacement solution and less than the deformation temperature of the preliminary tempered glass 90 . For example, when the ion replacement solution is a potassium nitrate (KNO ₃ ) solution, the preheating end temperature (T1) may be about 333 °C to 450 °C.

For example, the preliminary tempered glass 90 preheated to the preheating end temperature T1 may be immersed and heat treated in the ion replacement solution 310 of the tempering temperature T2 to be strengthened into the tempered glass product 100 .

For example, the pre-tempered glass 90, a small ion distribution on the surface after from (Na ⁺⁾ is missing, a large ion of the small ion ionic substitution solution (310) in the seat out (Na ⁺⁾ is missing (K ⁺⁾ As this is inserted, the preliminary tempered glass 90 may be strengthened.

For example, the size of a sodium ion (Na ⁺ ) atom is about 0.98 Å, and ^{the atomic size of a potassium ion (K +} ) is about 1.33 Å. can form. Accordingly, the tempered glass article 100 may be formed due to an increase in the density of the surface of the preliminary tempered glass 90 .

For example, the strengthening temperature T2 may be a temperature lower than the preheating end temperature T1. Accordingly, the surface compressive stress of the tempered glass may be primarily increased.

For example, the strengthening temperature (T2) may be greater than or equal to the melting point of the ion replacement solution 310 and less than or equal to about 400 °C. For example, the strengthening time may be between about 5 minutes and 60 minutes.

For example, the tempered preliminary tempered glass 90 may be heat-treated at a post-heating temperature (T3) less than the tempering temperature (T2). Accordingly, the surface compressive stress may be secondarily increased due to the difference ΔT between the strengthening temperature T2 and the post heating temperature T3.

For example, the difference ΔT between the strengthening temperature T2 and the post heating temperature T3 may be about 1 to 100°C.

If the difference (ΔT) between the strengthening temperature (T2) and the post-heating start temperature (T3) is less than 1 degree, the secondary surface compressive stress increase may not occur sufficiently, and the strengthening temperature (T2) and the post-heating start temperature (T3) If the difference (ΔT) exceeds about 100°C, structural damage may occur due to an excessive temperature difference.

Hereinafter, experimental examples including specific examples and comparative examples are presented to help the understanding of the present invention, but these are merely illustrative of the present invention and do not limit the appended claims, the scope and description of the present invention It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope of the spirit, and it is natural that such variations and modifications fall within the scope of the appended claims.

Example 1

A curved portion was formed on a glass thin film having a thickness of 70 μm using a jig. Tempered glass was prepared by immersing the glass thin film in which the bent portion was formed by a jig in an ion replacement solution.

Examples 2 to 4

Tempered glass was prepared in the same manner as in Example 1, except that the thickness of the glass and the method of forming the preliminary bent portion were the same as in Table 1 below.

Comparative Example 1

Tempered glass was prepared by immersing the glass thin film having a thickness of 70 μm in an ion replacement solution without forming a preliminary bend.

Comparative Example 2

Tempered glass was prepared in the same manner as in Comparative Example 1, except that the thickness of the glass thin film was the same as in Table 1 below.

division Glass thin film thickness (㎛) How to form a preliminary bend Example 1 70 use a jig Example 2 70 thermoforming Example 3 50 use a jig Example 4 50 thermoforming Comparative Example 1 70 - Comparative Example 2 50 -

Experimental Example: Measurement of Reinforcement Depth and Surface Compressive Stress

The strengthening depth and surface compressive stress of the outer and inner surfaces of the tempered glass prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were measured. For the depth of strengthening, the concentration of ^{K +} and Na ⁺ was measured by counting the number of atoms from the reference surface to the center of the cross-section of the tempered glass using EDAX. It was measured based on the measured concentration change of K ⁺ and Na ^{+ .} In the case of surface compressive stress, the stress value until the glass is broken was measured while pressing the surface of the tempered glass using an indenter.

The measurement results are shown in Table 2.

division outer side inner side inner radius
(mm) reinforcement depth
(μm) Surface compressive stress (Mpa) reinforcement depth
(μm) Surface compressive stress (Mpa) Example 1 14.3 704 10.1 838 2.71 Example 2 15.1 661 13.5 720 2.81 Example 3 10.7 722 8.4 881 1.47 Example 4 12.4 696 9.1 853 1.54 Comparative Example 1 13.5 712 13.8 709 3.17 Comparative Example 2 9.1 742 9.7 739 1.86

Referring to Table 2, in the case of the embodiment in which the bent portion is formed, the difference in the reinforcing depth between the outer and inner surfaces was 1 μm or more, and the difference in surface compressive stress was also 5% or more. Accordingly, the inner radius of the Examples was formed to be smaller than the inner radius of the Comparative Examples based on the same glass thickness.

In addition, Examples 1 and 3 in which the preliminary bent portion was formed using a jig had an inner radius smaller than that of Examples 2 and 4 in which the preliminary bent portion was formed through a thermoforming method.

Therefore, as the inner radius of the glass-reinforced product is formed to be small, it is more easily applied to a flexible display device, and the impact that the glass-reinforced product receives in the process of repeatedly bending and unfolding the glass-reinforced product is reduced.

80: glass disc 90: preliminary tempered glass
100: tempered glass product 110: bent portion
200: injection device 210: etchant
300: fortification tank 310: ion replacement solution
400: jig body 420: support
X: inner side Y: outer side
A: bending angle Z: center line
C: bent portion formation position

Claims (16)

A tempered glass article comprising a bend, comprising:
The bent portion is different from the strengthening depth of the inner surface and the strengthening depth of the outer surface, tempered glass article.
The tempered glass article of claim 1 , wherein the strengthening depth of the outer side is 5 to 50% greater than the strengthening depth of the inner side.
The tempered glass article of claim 1 , wherein the surface compressive stress of the outer side is 5 to 50% greater than the surface compressive stress of the inner side.
The tempered glass article of claim 1 , wherein the bend angle of the bend is 0 to 150°.
The tempered glass article of claim 1 , wherein when the bend angle of the bend is 0°, the inner radius of the bend is 0.1R to 5R.
The tempered glass article of claim 1 comprising at least two bends.
The tempered glass article of claim 1 , wherein the thickness of the tempered glass article is between 10 and 100 μm.
The tempered glass article according to claim 1, wherein the bent portion is formed in a region where a distance from a center line perpendicular to the longitudinal direction with respect to the length of the tempered glass article is 20% or less with respect to the length of the tempered glass article.
The tempered glass article according to claim 1, wherein the tempered glass article is used as a protective film of a flexible display.
preparing a preliminary tempered glass by etching the glass original plate;
forming a preliminary bending portion in the preliminary tempered glass; and
A method of manufacturing a tempered glass article, comprising the step of chemically strengthening the pre-tempered glass including the pre-bend portion through an ion displacement solution.
The method according to claim 10, wherein the preparing of the preliminary tempered glass comprises etching both sides or one side of the glass original plate using an etchant.
The method of claim 10 , wherein the forming of the preliminary bending portion forms the preliminary bending portion by applying a physical force to the preliminary tempered glass.
The method of claim 12 , wherein forming the preliminary bend forms the preliminary bend using a jig.
The method of claim 13 , wherein the chemically strengthening the pre-tempered glass comprises chemically strengthening the pre-strengthened glass together with the jig in the ion displacement solution.
The method of claim 10 , wherein the forming of the preliminary bending portion comprises thermoforming the preliminary tempered glass to form the preliminary bending portion.
The method of claim 10 , wherein the ion displacement solution comprises potassium nitrate (KNO ₃ ).

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