Method for manufacturing cover window, cover window and display device including the same

Abstract

Provided are a method for manufacturing a cover window, a cover window, and a display device including the same. The method for manufacturing the cover window includes: preparing a glass product with a flat upper surface; forming a recessed portion in which a portion of the upper surface is recessed on the glass product and forming a mask layer including water glass; and etching the mask layer and the glass product to form a cover window in which a portion of the upper surface is partially recessed.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a cover window, a cover window and a display device including the same, and more particularly to a method for manufacturing a cover window partially having a thin area using water glass and a cover window manufactured by the same. Background Art

[0002] With the development of multimedia, the importance of display devices is increasing. In response, various display devices such as organic light emitting display devices (OLED) and liquid crystal display devices (LCD) are being used.

[0003] On the other hand, cover windows are often used in electronic devices including display devices, building materials, etc. For example, cover windows are applied to substrates of flat panel display devices such as liquid crystal display devices and OLEDs, or are applied to protect such substrates.

[0004] Recently, foldable display devices are being studied for user convenience. A cover window used in a foldable display device preferably has a thin thickness in order to relax bending stress when folded. Summary of the invention

[0005] An object of the present invention is to provide a method for manufacturing a cover window including a narrow portion partially having a concave shape using water glass.

[0006] Another problem to be solved by the present invention is to provide a cover window in which a thin portion is not recognized from the outside by using the above method, and a display device including the cover window.

[0007] The subject of the present invention is not limited to the subject mentioned above, and those skilled in the art should be able to clearly understand unmentioned or other subjects through the following description.

[0008] An embodiment for solving the above-mentioned problem relates to a method for manufacturing a cover window, comprising: preparing a glass product having a flat upper surface; forming a recessed portion in which a portion of the upper surface is recessed on the glass product and forming a mask layer including water glass; and etching the mask layer and the glass product to form a cover window in which a portion of the upper surface is partially recessed.

[0009] The step of forming the mask layer may include: coating a water glass layer on the upper surface of the glass product; and etching a portion of the upper surface of the water glass layer to form the mask layer.

[0010] The mask layer may include the concave portion and a flat portion connected to the concave portion and having a flat upper surface, and the thickness of the concave portion is smaller than the thickness of the flat portion.

[0011] The concave portion may include a first portion having a flat upper surface and a second portion connecting the first portion and the flat portion and having an inclined upper surface.

[0012] The concave portion may have a shape in which an upper surface is curved.

[0013] Alternatively, the step of forming the cover window may be performed by a wet etching process.

[0014] It may be that, in the step of forming the cover window, the mask layer is dissolved by an etching solution, and a portion of the upper surface of the glass product is etched.

[0015] In the glass product, a portion of the mask layer corresponding to the concave portion may be etched so that the upper surface has a curvature, and a portion corresponding to a region other than the concave portion may be etched so that the upper surface is flat.

[0016] It may be that the mask layer and the glass product are over-etched by wet etching.

[0017] It may be that the maximum thickness of the cover window is smaller than the thickness of the glass product.

[0018] The cover window may include a first surface and a flat second surface opposite to the first surface, and further includes a flat non-slender portion of the first surface and a slender portion of the first surface that is partially recessed and has a thickness smaller than that of the non-slender portion.

[0019] The portion of the first surface where the thin portion is located may have a curved shape.

[0020] The first thickness of the non-slender portion may be in a range of 0.1 mm to 20 mm, and the second thickness of the slender portion may be in a range of 0.01 mm to 0.1 mm.

[0021] The narrow portion may have a width in a range of 20 mm or less.

[0022] The cover window may be folded with the folding line located at the thin portion as a reference so that the first surface faces inward.

[0023] An embodiment for solving the above-mentioned problem involves a cover window including a first surface and a second surface which is flat and opposite to the first surface, and is folded with a folding line as a reference so that the first surface faces inward. The cover window includes: a flat non-slender portion of the first surface; and a slender portion, wherein the first surface is partially recessed and has a thickness smaller than that of the non-slender portion, and the folding line is located in the slender portion.

[0024] The first thickness of the non-slender portion may be in a range of 0.1 mm to 20 mm, and the second thickness of the slender portion may be in a range of 0.01 mm to 0.1 mm.

[0025] The narrow portion may have a width in a range of 20 mm or less.

[0026] In a state where the first surface is folded based on the folding line, a length of the thin portion measured to a radius of curvature may be within a range of about 2 mm.

[0027] An embodiment for solving the above-mentioned problem involves a display device which is a foldable display device which is folded with a display surface facing inward, and includes: a display panel, including a surface located in the front and another surface located in the rear, and displaying a picture facing the front; a cover window, which is arranged on one surface of the display panel and includes a first surface and a second surface which is opposite to the first surface and is flat; and a coupling component, which is arranged between the second surface of the cover window and the display panel, and the cover window includes a flat non-slender portion of the first surface and a slender portion of the first surface which is partially recessed and has a thickness less than that of the non-slender portion.

[0028] Details of other embodiments are included in the detailed description and drawings.

[0029] (Effects of the Invention)

[0030] The manufacturing method of the cover window involved in one embodiment can use a method of etching a glass product using water glass to manufacture a cover window partially including a thin portion according to the shape of the water glass. In the cover window manufactured in this way, the thin portion having a concave shape cannot be recognized from the outside, and applying it to a foldable display can improve the recognition of the display device.

[0031] The effects of each embodiment are not limited to the above examples, and more effects are included in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic three-dimensional diagram of a cover window involved in an embodiment.

[0033] Figure 2 Yes means Figure 1A three-dimensional diagram of a cover window in a folded state.

[0034] Figure 3 It is a side view of a cover window involved in one embodiment.

[0035] Figure 4 It is a cross-sectional view showing a thin part in a folded state of a cover window according to an embodiment.

[0036] Figure 5 It is a flowchart showing a method for manufacturing a cover window according to an embodiment.

[0037] Figures 6 to 11 The following are cross-sectional views sequentially showing the manufacturing steps of the cover window according to one embodiment.

[0038] Fig.12 and Fig.13 The following are cross-sectional views sequentially showing the manufacturing steps of the cover window according to another embodiment.

[0039] Fig.14 is a cross-sectional view showing a display device including a cover window according to an embodiment.

[0040] Fig.15 yes Fig.14 Schematic cross-sectional view of a display device.

[0041] Fig.16 Yes means Fig.14 A cross-sectional view of a display device in a folded state.

[0042] Explanation of symbols:

[0043] 100: cover window; SP: slim part; NSP1, NSP2: non-slim part; US: first side; LS: second side; FL: folding line; R: center of curvature; GP: glass product; GM: mask layer; WG: water glass layer; 10: display device; 300: bonding part; 200: display panel; DPA: display area; NDA: non-display area; FDA: folding area; NFA1, NFA2: non-folding area. DETAILED DESCRIPTION

[0044] References and Attachments Figure 1 The advantages, features and methods of achieving the advantages and features of the present invention will become clear from the detailed description of the embodiments below. However, the present invention is not limited to the embodiments disclosed below, and can be implemented in different forms. The embodiments are only provided to make the disclosure of the present invention complete and to fully inform the scope of the invention to those skilled in the art. The present invention should be defined only by the scope of the claims.

[0045] The case where an element or layer is located on other elements or layers includes not only the case where it is directly located on other elements, but also the case where other layers or other elements are present therebetween. Similarly, references to "below", "left" and "right" include the case where it is directly adjacent to other elements and the case where other layers or other elements are present therebetween. Throughout the specification, the same symbol refers to the same constituent element.

[0046] Although the terms "first" and "second" are used to describe each component, each component is certainly not limited to these terms. These terms are only used to distinguish one component from other components. Therefore, within the technical concept of the present invention, the first component mentioned below can certainly be the second component.

[0047] Hereinafter, each embodiment will be described with reference to the drawings.

[0048] Figure 1 It is a schematic three-dimensional diagram of a cover window involved in an embodiment. Figure 2 Yes means Figure 1 A three-dimensional diagram of a cover window in a folded state. Figure 3 It is a side view of a cover window involved in one embodiment.

[0049] In this specification, "upper part", "top", and "upper surface" refer to the upper direction based on the cover window 100, that is, one direction of the third direction DR3, and "lower part", "bottom", and "lower surface" refer to the other direction of the third direction DR3. In addition, "left", "right", "upper", and "lower" refer to directions when the cover window 100 is observed on a plane. For example, "left" is one direction of the first direction DR1, "right" is the other direction of the first direction DR1, "up" is one direction of the second direction DR2, and "down" is the other direction of the second direction DR2.

[0050] Reference Figures 1 to 3 The cover window 100 can be used not only for tablet PCs, notebook PCs, smart phones, e-books, televisions, and PC displays, but also for protecting displays in electronic devices including displays such as refrigerators and washing machines. The cover window 100 can also be used for cover glass of automobile dashboards, cover glass for solar cells, built-in materials of building materials, windows of buildings or buildings, and the like.

[0051] In one embodiment, the cover window 100 may be in a flat sheet shape or a flat plate shape. The planar shape of the cover window 100 may be a rectangle, but is not limited thereto, and may have various shapes such as a chamfered rectangle, a square, a circle, an ellipse, etc. In other embodiments, the cover window 100 may be in a three-dimensional shape including a bent portion. For example, the edge of the flat portion may be tortuous or may be an arc as a whole. In addition, in one embodiment, the cover window 100 may have a flexible property and may be folded based on the folding line FL.

[0052] The cover window 100 includes a first surface US and a second surface LS which is the opposite surface of the first surface US. The first surface US may be the upper surface of the cover window 100, and the second surface LS may be the lower surface of the cover window 100. The cover window 100 has a rectangular shape in a plan view, and may have a shape in which the intersection of the edges extending in the first direction DR1 and the second direction DR2 is bent. The first surface US and the second surface LS are opposite to each other in the thickness direction. When the cover window 100 is included in the display device ( Fig.14 In the case where the cover window 100 has a "10" (shown in FIG. 1 ) and plays a role of allowing light to pass through, light can mainly enter from one of the first surface US and the second surface LS and pass through the other surface. In the accompanying drawings, the length of each side extending in the first direction DR1 of the cover window 100 is longer than the length of each side extending in the second direction DR2, but it is not limited to this.

[0053] The cover window 100 is required to have high strength. For example, in the case of window glass, in order to meet the requirements of high transmittance and light weight, it is preferred to have a thin thickness and a strength that is not easily broken by external impact.

[0054] In one embodiment, the cover window 100 includes a glass composition. The glass composition of the cover window 100 may include various compositions known in the art. In one embodiment, the glass composition may include LAS glass ceramics containing lithium aluminum silicate. For example, the glass composition may contain SiO in an amount of 50 to 80 mol%. 2 , containing Al in an amount of 1 to 30 mol% 2 O 3 , containing B in an amount of 0 to 5 mol% 2 O 3 , containing P in an amount of 0 to 4 mol% 2 O 5 , containing Li in an amount of 3 to 20 mol% 2 O, containing Na in an amount of 0 to 20 mol% 2 O, containing K in an amount of 0 to 10 mol% 2O, MgO at a content of 3 to 20 mol%, CaO at a content of 0 to 20 mol%, SrO at a content of 0 to 20 mol%, BaO at a content of 0 to 15 mol%, ZnO at a content of 0 to 10 mol%, TiO at a content of 0 to 1 mol% 2 and containing ZrO in an amount of 0 to 8 mol % 2 .

[0055] Here, "content is 0 mol %" means that the corresponding component is not substantially contained. That a composition does not substantially contain a specific component means that it is intentionally not contained in raw materials, etc., including the case where a trace amount of impurities such as 0.1 mol % or less is inevitably contained.

[0056] The components of the glass composition are described in more detail, namely, SiO 2 It constitutes the skeleton of glass, plays the role of improving chemical durability and reducing the generation of cracks when defects (indentations) occur on the glass surface. In order to fully perform the above-mentioned functions, SiO can be included in an amount of 50 mol% or more. 2 In order to achieve sufficient melting properties, SiO 2 The content is 80 mol% or less.

[0057] Al 2 O 3 It plays a role in improving the breakability of glass. 2 O 3 It can produce less fragments when the glass breaks. 2 O 3 It can improve the ion exchange performance during chemical strengthening and can act as an effective component to increase the surface compressive stress after strengthening. 2 O 3 When the content of Al is 1 mol% or more, the above functions can be effectively performed. On the other hand, in order to maintain the acid resistance and melting property of the glass, Al 2 O 3 The content is below 30 mol%.

[0058] B 2 O 3 Improves the glass's spalling resistance and improves its melting properties. 2 O 3 , but in the case of B containing more than 0.5 mol% 2 O 3 When the melting point of the glass is increased, the melting point of the glass can be further improved. 2 O 3When the content of is 5 mol% or less, the generation of texture during melting can be suppressed.

[0059] P 2 O 5 Improves ion exchange performance and peeling resistance. P can also be omitted 2 O 5 , but in the case of containing more than 0.5 mol% P 2 O 5 When the function is effectively performed. 2 O 5 A content of 4 mol% or less can prevent a significant decrease in breakage and acid resistance.

[0060] Li 2 O plays a role in forming surface compressive stress through ion exchange. Li ions arranged near the glass surface can be exchanged for Na ions or the like through the ion exchange process. 2 O can also improve the breakability of glass. Li for efficient ion exchange 2 The content of O is 3 mol % or more, and preferably has a content of 20 mol % or less in consideration of acid resistance.

[0061] Na 2 O forms surface compressive stress through ion exchange, which plays a role in improving the solubility of the glass. The Na ions arranged near the glass surface can be exchanged for K ions, etc. through the ion exchange process. Na 2 O, but contains Na 2 In the case of O, a content of 1 mol% or more is preferred for effectively performing the above-mentioned functions. In the case where only the exchange process of Li ions and Na ions exists and there is no exchange process of K ions, in order to smoothly exchange Li ions and Na ions, Na 2 It is preferable that the content of O is less than 8 mol%. In the case of a K ion exchange process, a larger amount of Na 2 O, but even in this case, when considering acid resistance, it may be preferable to have a content of 20 mol% or less.

[0062] K 2 O improves ion exchange performance and is related to fragmentation. K can also be omitted 2 O, but in order to improve the ion exchange performance, it can contain 0.5 mol% or more. K to prevent excessive decrease in crushing properties 2 The content of O may be less than 10 mol %.

[0063] MgO increases the surface compressive stress of chemically strengthened glass and improves crushability. The above-mentioned effects can be effectively performed when the content is 3 mol% or more. When the content of MgO is 20 mol% or less, the possibility of devitrification during glass melting can be reduced.

[0064] CaO plays a role in improving the melting property of glass and improving crushability. CaO can be omitted, but in order to effectively perform the above-mentioned functions, it is preferably present in an amount of 0.5 mol% or more. If the CaO content is too high, the ion exchange performance may decrease, so it is preferred that the CaO content has a value of 20 mol% or less.

[0065] SrO, like CaO, plays a role in improving the melting property of glass and improving crushability. SrO can be omitted, but in order to effectively perform the above-mentioned functions, it is preferably 0.5 mol% or more. If the content of SrO is too large, the ion exchange performance may decrease, so the content of SrO is preferably 20 mol% or less.

[0066] BaO plays a role in improving the melting property of glass and improving crushability. BaO can be omitted, but in order to effectively perform the above-mentioned functions, it is preferably 0.5 mol% or more. When the content of BaO is 15 mol% or less, it can be helpful to prevent excessive decrease in ion exchange performance.

[0067] ZnO plays a role in improving the melting property of the glass. ZnO can be omitted, but when the content of ZnO is 0.25 mol% or more, a significant melting property improvement effect can be brought about by containing ZnO. In order to prevent the weather resistance from decreasing, it is preferred to maintain the content of ZnO below 10 mol%.

[0068] TiO 2 Improves the breakability of chemically strengthened glass. TiO can be omitted 2 , in the case of TiO with a content of 0.1 mol% or more 2 When TiO 2 When considering the prevention of devitrification during melting, TiO 2 The content is 1 mol% or less.

[0069] ZrO 2 The surface compressive stress based on ion exchange can be increased, and the crushability of the glass can be improved. ZrO can be omitted 2 However, when the content is 0.5 mol% or more, the above-mentioned effects can be effectively performed. ZrO 2When the content of is below 8 mol%, the devitrification phenomenon during melting can be suppressed.

[0070] In addition to the above-listed components, the glass composition may also include Y 2 O 3 ,La 2 O 3 , Nb 2 O 5 、 2 O 5 , Gd 2 O 3 The composition ratio of the glass composition of the cover window 100 can be changed through a molding process or an ion exchange process.

[0071] According to one embodiment, the cover window 100 may have a soft property and may be folded. In this specification, "folding" is used not only to mean a device that is folded, but also to mean a device that can have a folded state and an unfolded state. In addition, folding is representative of a situation where it is folded at an angle of about 180°, but is not limited thereto. In the case where the angle of the bend exceeds 180° or is less than 180°, for example, when it is bent at an angle greater than or equal to 90° and less than 180°, or greater than or equal to 120° and less than 180°, it can also be understood as being folded. At the same time, for the folded state, even if it does not constitute a complete fold, but when it is out of the unfolded state and in the bent state, it can also be called a folded state. For example, even if it is bent at an angle less than or equal to 90°, as long as the maximum folding angle is greater than or equal to 90°, in order to distinguish it from the unfolded state, it can be expressed as being in a folded state.

[0072] The cover window 100 may be folded with the folding line FL as a reference. The folding line FL may be a straight line extending along a direction (e.g., the second direction DR2) on a plane. In the drawings, the folding line FL is illustrated as extending in parallel with the short side of the cover window 100, but it is not limited thereto, and the folding line FL may also be parallel to the long side or inclined relative to the short side and the long side.

[0073] In some embodiments, the folding line FL of the cover window 100 may also be determined at a specific position. In the cover window 100, the folding line FL determined at a specific position may be one or more than two. In other embodiments, the folding line FL may also be freely set in various areas in the cover window 100 without being specified in its position.

[0074] On the other hand, as described above, in order to protect the electronic device including the display, the cover window 100 may be required to have a strength above a certain level, but at the same time, it may have a flexible property that can be folded based on the folding line FL. The strength of the cover window 100 and whether it can be folded may be associated with the thickness of the cover window 100. In the case of a thick thickness, the mechanical strength of the cover window 100 can be ensured, but the flexibility will be somewhat reduced. On the contrary, in the case of a thin thickness of the cover window 100, it can be smoothly folded with flexibility, but it may be difficult to ensure the mechanical strength for protecting electronic devices, etc. In view of this property, the cover window 100 involved in one embodiment may include: a slender portion SP, which is a peripheral portion of the folding line FL and has a thin thickness; and non-slender portions NSP1 and NSP2, which are portions other than the slender portion SP, where the folding line FL is not formed, and have a thick thickness.

[0075] The slender portion SP is a peripheral portion of the folding line FL, and the slender portion SP may be arranged with the folding line FL as the center. In the slender portion SP, the first surface US of the cover window 100 may be a portion that is partially recessed and has a recessed (Recess) shape. The slender portion SP may be formed to have a thin thickness corresponding to the area where the cover window 100 is folded. In one embodiment, the first surface US may have a shape that is recessed in a curvature manner in the slender portion SP, and the slender portion SP may have a shape in which the thickness gradually decreases relative to the non-slender portions NSP1 and NSP2. The first surface US has a shape that is slowly recessed at the slender portion SP, so that it can better resist the compressive stress caused when the cover window 100 is folded, and can also prevent parts of the first surface US from directly abutting each other when folded.

[0076] With the slender portion SP as a reference, the cover window 100 can be divided into a first non-slender portion NSP1 and a second non-slender portion NSP2. The first non-slender portion NSP1 can be located on one side (e.g., the left side) of the folding line FL, and the second non-slender portion NSP2 can be located on the other side (e.g., the right side) of the folding line FL. In the case where the folding line FL is determined at a specific position, the first non-slender portion NSP1 and the second non-slender portion NSP2 can be specified as areas that do not constitute a fold. The first non-slender portion NSP1 and the second non-slender portion NSP2 can have the same width, respectively, but are not limited to this. In the case of an unspecified folding line FL, the first non-slender portion NSP1 and the second non-slender portion NSP2 can have different areas depending on the position of the set folding line FL. The first non-slender portion NSP1 and the second non-slender portion NSP2 can each have a flat shape of the first surface US and can have a uniform thickness. Each non-slim portion NSP1, NSP2 is a region that is spaced apart from the folding line FL and is not folded, and has a certain degree of thickness, so that it can have durability against external impact. That is, in the cover window 100, the first surface US can have a partially concave or flat shape depending on the position, and on the contrary, the second surface LS can be formed flat regardless of the position, so that the slim portion SP and the non-slim portions NSP1, NSP2 can have different thicknesses from each other.

[0077] Figure 4 It is a cross-sectional view showing a thin part in a folded state of a cover window according to an embodiment.

[0078] Combination Figures 1 to 3 And further refer to Figure 4 The cover window 100 can be folded in an inner folding manner in which the first surface US is facing inward and the two surfaces are folded toward each other, or can be folded in an outer folding manner in which the first surface US is facing outward. The cover window 100 can be folded in only one of the inner folding manner and the outer folding manner, or can be folded in both inner and outer folding manners. In the case of the cover window 100 that realizes both inner folding and outer folding, the inner folding and the outer folding can be realized based on the same folding line FL, or can be a plurality of folding lines FL that perform folding in different ways, including a folding line dedicated to inner folding and a folding line dedicated to outer folding.

[0079] The thickness T1 and T2 of the cover window 100 are defined by the distance between the first surface US and the second surface LS. In one embodiment, the first thickness T1 of the non-slim portions NSP1 and NSP2 of the cover window 100 may be in the range of 0.1 mm to 2 mm. As the non-slim portions NSP1 and NSP2 of the cover window 100 that are not folded have a thickness within the above range, especially a thickness of at least 0.1 mm, the cover window 100 may have minimal durability against external impact.

[0080] On the contrary, the second thickness T2 as the minimum thickness of the slender portion SP of the cover window 100 can have a range of 0.01mm to 0.1mm, and its width W can have a range of 1mm to 20mm. The slender portion SP is an area that is folded based on the folding line FL, and can have a relatively thin thickness so that it can be folded smoothly. As the slender portion SP has a thickness of less than 0.1mm, preferably in the range of 0.01mm to 0.03mm, the cover window 100 can somewhat reduce the repulsive force caused by folding at the slender portion SP. In the slender portion SP, the depth of the recessed portion of the first surface US can have a range of more than 0.07mm and less than 0.1mm, and when the cover window 100 is folded, the radius of curvature RD measured from its center of curvature R to the first surface US of the cover window 100 can be less than 5mm, preferably in the range of 1mm to 2mm. As the cover window 100 according to an embodiment includes the thin portion SP and the non-slim portions NSP1 and NSP2 having different thicknesses, the non-slim portions NSP1 and NSP2 can have flexibility for achieving smooth folding while ensuring durability against external impact.

[0081] On the other hand, as described above, the cover window 100 including the thin portion SP can be prepared by preparing a glass product having a flat surface and manufacturing it through a molding process of etching one side of the glass product. The molding process of the glass product can be performed by a method of etching or pressurizing a part of the cover window 100 to form the thin portion SP, in which case the boundary between the thin portion SP and the non-slim portions NSP1 and NSP2 may be recognized from the outside. In order to prevent this, the manufacturing method of the cover window 100 involved in one embodiment can be performed by a process of etching the glass product using water glass having a component similar to that of the glass composition. The cover window 100 can be manufactured by performing a process of etching the glass product together with the water glass, thereby simplifying the manufacturing process and preventing the thin portion SP of the cover window 100 from being recognized from the outside.

[0082] Hereinafter, a method for manufacturing the cover window 100 according to an embodiment will be described with reference to other drawings.

[0083] Figure 5 It is a flowchart showing a method for manufacturing a cover window according to an embodiment.

[0084] Reference Figure 5 The manufacturing method of the cover window 100 according to an embodiment may include a step S100 of preparing a glass product, a step S200 of forming a mask layer on the glass product, and a step S300 of etching the mask layer and the glass product. The glass product may include a glass composition and form the cover window 100 after an etching process.

[0085] Figures 6 to 11The present invention is a cross-sectional view sequentially showing the manufacturing steps of the cover window according to one embodiment.

[0086] First, refer to Figure 6 A glass product GP including a glass composition is prepared (S100). The glass product GP may have a plate shape having a flat upper surface.

[0087] The glass product GP may have the composition of the cover window 100 described above. In one embodiment, the glass product GP may include LAS glass ceramics containing lithium aluminum silicate. For example, the glass composition may contain 50 to 80 mol% of SiO 2 , 1 to 30 mol% Al 2 O 3 , 0 to 5 mol% content of B 2 O 3 , 0 to 4 mol% P 2 O 5 , 3 to 20 mol% Li 2 O, 0 to 20 mol% Na 2 O, 0 to 10 mol% K 2 O, 3 to 20 mol% MgO, 0 to 20 mol% CaO, 0 to 20 mol% SrO, 0 to 15 mol% BaO, 0 to 10 mol% ZnO, 0 to 1 mol% TiO 2 and 0 to 8 mol% ZrO 2 Here, "0 mol% content" means that the corresponding component is substantially not contained. The fact that the composition does not substantially contain a specific component means that the corresponding component is intentionally not contained in the raw materials, etc., for example, including the case where a trace amount of impurities such as 0.1 mol% or less is inevitably contained. The description of each component of the glass product GP is the same as above. In addition to the components listed above, the glass product GP may also include Y 2 O 3 ,La 2 O 3 , Nb 2 O 5 、 2 O 5 , Gd 2 O 3 And other ingredients.

[0088] In some embodiments, the glass product GP may be manufactured through a forming step, a cutting step, a chamfering step, a repairing step, a high temperature / high humidity treatment step, and a chemical strengthening step of the glass composition.

[0089] For example, the step of forming the glass composition may be a step of preparing a glass composition having the above-mentioned composition and forming it into a specific shape. The glass composition may be formed into a flat plate shape by various methods known in the art. For example, it may be formed by a float process, a fusion draw process, a slot draw process, etc. However, it is not limited thereto.

[0090] Next, the formed glass composition can be cut through a cutting step. The glass composition formed into a flat plate shape can have a size different from that of the glass product GP. For example, the glass composition can be formed in a large-area substrate state as a mother glass including a plurality of glass compositions, and it can be cut into a plurality of units, so that a plurality of glass compositions can be manufactured. For example, assuming that the glass product GP has a size of about 6 inches, it can be formed into a glass composition having a size several to hundreds of times (for example, 120 inches) and then cut, and 20 glass compositions formed into a flat plate shape can be obtained at the same time. The cutting process of the glass composition can be performed using a cutting knife, a cutting wheel, a laser, etc. However, it is not limited to this.

[0091] Next, the cut glass composition is subjected to a chamfering process. In the chamfering process, the cut glass composition and the cut dummy substrate are bonded to each other through an adhesive layer to form a chamfered surface of each cut glass composition. The chamfering process of the cut glass composition can be achieved by computerized numerical control (CNC). By chamfering the cut glass composition, the occurrence of breakage or chipping of the cut surface of the glass composition can be prevented in advance.

[0092] Next, the chamfered glass composition is repaired or surface treated. If the chamfered glass composition is surface treated, the reduced strength of the side surface of the glass composition can be improved. The surface treatment process of the chamfered glass composition can be performed using a surface treatment solution containing fluoride ions. In some embodiments, a polishing step of the glass composition can be performed between the chamfering process and the surface treatment process.

[0093] Next, the surface-treated glass composition is subjected to a high temperature / high humidity treatment. The high temperature / high humidity treatment process can be performed on the surface-treated glass composition in a chamber for about 2 hours to 4 hours, wherein the chamber is adjusted to a temperature condition of 80° C. to 90° C. and a humidity condition of 80% to 90%.

[0094] Next, the glass composition is chemically strengthened to form a glass product GP. The chemical strengthening step can be performed by an ion exchange process, and the formed glass product GP can have excellent durability, strength or compressive stress. The above-mentioned process is a process performed to make the glass product GP have sufficient durability, and is not necessarily limited thereto. A previous process for adjusting the characteristics of the glass product GP can be performed according to the product to which the cover window 100 is applied.

[0095] Next, refer to Figure 7 and Figure 8 , a mask layer GM is formed on the glass product GP (S200). According to an embodiment, the mask layer GM may include water glass. As the mask layer GM includes water glass, the water glass may be removed together with the etching liquid used in the etching process of the glass product GP. Compared with the patterning process using a general mask, the mask removal process is omitted, thereby reducing the manufacturing process. In addition, the mask layer GM including water glass is applied to the glass product GP, and an etching process based on an etching selectivity is performed, so that the glass product GP can be formed into a desired shape.

[0096] That is, the mask layer GM may have a structure for etching the glass product GP according to the shape of the cover window 100. For example, the mask layer GM may include a flat portion with a flat upper surface and a recessed portion RP with a partially recessed upper surface. In a subsequent process, if the mask layer GM and the glass product GP are etched simultaneously, the portion of the glass product GP corresponding to the recessed portion RP may form the slim portion SP of the cover window 100, and the portion corresponding to the flat portion may form the non-slim portions NSP1 and NSP2 of the cover window 100. The flat portion of the mask layer GM is a portion having a uniform thickness and a shape with a flat upper surface, and a plurality of flat portions may be divided based on the recessed portion RP. The recessed portion RP is a portion with a partially recessed upper surface, and may have a thickness thinner than the flat portion.

[0097] Such a mask layer GM may be formed by etching only a portion of the upper surface of the water glass layer WG after coating the water glass layer WG on the glass product GP. The mask layer GM may have a recessed portion RP by etching a portion of the water glass layer WG, and the recessed portion RP and the portion other than the recessed portion RP may have different thicknesses from each other. The drawings illustrate a case where the mask layer GM is formed by etching the water glass layer WG without other masks, but the invention is not limited thereto.

[0098] In one embodiment, the recessed portion RP of the mask layer GM may include a first portion having a flat upper surface and a second portion having an inclined upper surface. The second portion having an inclined upper surface of the recessed portion RP is a portion connecting the flat portion of the mask layer GM and the first portion having a flat upper surface in the recessed portion RP. The mask layer GM may have a shape in which the recessed portion RP is angular in a linear shape as a whole, but is not limited thereto. The upper surface of the mask layer GM may also be partially recessed in a curvature to form a gently curved shape of the recessed portion RP.

[0099] The upper surface of the mask layer GM is recessed at the recessed portion RP, so that the thickness of the recessed portion RP can be smaller than other portions, and the etching amount of the glass product GP etched together with the mask layer GM can be different according to the position. The portion of the glass product GP corresponding to the recessed portion RP of the mask layer GM can be etched more than other portions, and the corresponding portion can form the thin portion SP of the cover window 100.

[0100] Then, refer to Fig. 9 and Fig.10 , the mask layer GM and the glass product GP are etched at the same time (S300), thereby manufacturing the cover window 100. The mask layer GM may include water glass and dissolve in the etching solution for etching the glass product GP, thereby being removed. During the period when the glass product GP and the recessed portion RP of the mask layer GM are etched at different speeds, the mask layer GM is dissolved and removed. By etching the glass product GP using the mask layer GM including water glass, the manufacturing process steps of the cover window 100 can be reduced to one step.

[0101] According to one embodiment, the etching process of the mask layer GM and the glass product GP may be performed through an over-etching process. In the over-etching process, as the glass product GP is etched together with the mask layer GM, the first thickness T1 of the non-fine parts NSP1 and NSP2 in the finally manufactured cover window 100 may be smaller than the third thickness T3 of the glass product GP. The glass product GP may be etched on the entire surface according to the shape of the mask layer GM, and a fine part SP may be formed in a portion where the recessed part RP is provided, and non-fine parts NSP1 and NSP2 may be formed in the portion other than the recessed part. The cover window 100 manufactured using the mask layer GM including water glass may control the etching selectivity according to the shape of the mask layer GM, so that a fine part SP in which the first surface US is partially recessed may be formed.

[0102] According to an embodiment, the process of etching the mask layer GM and the glass product GP may be performed by wet etching, and a portion of the glass product GP corresponding to the recessed portion RP of the mask layer GM may be etched by isotropic etching.

[0103] Fig.11The schematic diagram shows that a portion of the glass product GP corresponding to the recessed portion RP of the mask layer GM is etched to form a thin portion SP. Fig.11 The cover window 100 formed by etching the glass product GP may have a thin portion SP whose upper surface is partially recessed in a curvature and flat non-slim portions NSP1 and NSP2. Even if the recessed portion RP of the mask layer GM has an overall linear angular shape, the portion of the first surface US of the cover window 100 corresponding to the thin portion SP may have a gently curved shape by wet etching.

[0104] However, the present invention is not limited thereto, and the recessed portion RP of the mask layer GM may also have a shape with a slow curvature corresponding to the shape of the thin portion SP of the cover window 100 .

[0105] Fig.12 and Fig.13 2 is a cross-sectional view showing in sequence the manufacturing steps of the cover window according to another embodiment. Fig.12 and Fig.13 , the shape of the mask layer GM_1 and the etching process of the mask layer GM_1 and the glass product GP are shown.

[0106] Reference Fig.12 and Fig.13 In the manufacturing process of the cover window 100 according to an embodiment, the mask layer GM_1 may include a flat portion with a flat upper surface and a concave portion RP with a gently curved upper surface. Figure 7 The difference between the embodiments is that the recessed portion RP of the mask layer GM_1 has a different shape. Hereinafter, repeated contents are omitted and the shape of the mask layer GM_1 is described in detail.

[0107] The concave portion RP of the mask layer GM_1 has a thickness thinner than the flat portion, and an upper surface of the concave portion RP may have a gently curved shape. Figure 7 In the embodiment, the recessed portion RP may have a shape in which there is no first portion with a flat upper surface, and the thickness thereof varies with the position starting from the portion connected to the flat portion. The cover window 100 manufactured by the etching process includes a thin portion SP in which a portion of the first surface US is recessed in a curvature, and thus the shape of the mask layer GM_1 may be formed corresponding thereto. Even if the glass product GP is isotropically etched by the wet etching process, if the thin portion SP is not formed smoothly, the shape of the mask layer GM_1 may be designed as follows: Fig.12 As shown in the figure, the shape of the thin portion SP of the cover window 100 can be realized.

[0108] According to an embodiment, the glass product GP can be made into a cover window 100 by a wet etching process using a mask layer GM_1 including water glass, and the cover window 100 can include a thin portion SP formed corresponding to the recessed portion RP of the mask layer GM_1. For the cover window 100 manufactured by the over-etching process of the mask layer GM_1 including water glass and the glass product GP, the glass product GP is partially etched in the entire surface to form the thin portion SP and the non-slim portions NSP1 and NSP2, so that their boundaries can be prevented from being recognized from the outside. In addition, the cover window 100 manufactured in this way has an advantage in that the product durability is increased by including the non-slim portions NSP1 and NSP2 having a thickness greater than the thin portion SP.

[0109] The cover window 100 manufactured by the above method can be used in a display device including a plurality of pixels and capable of displaying images. In particular, the foldable cover window 100 can be effectively used in a foldable display device.

[0110] Fig.14 is a cross-sectional view showing a display device including a cover window according to an embodiment. Fig.15 yes Fig.14 Schematic cross-sectional view of a display device. Fig.16 Yes means Fig.14 A cross-sectional view of a display device in a folded state.

[0111] Reference Figures 14 to 16 The display device 10 displays a screen or image through the display area DPA, and various devices including the display area DPA may be included in the display device 10. Examples of the display device 10 are not limited thereto, and may include various home appliances including the display area DPA, such as smart phones, portable phones, tablet PCs, PDAs (Personal Digital Assistants), PMPs (Portable Multimedia Players), televisions, game consoles, watch-type electronic devices, head-mounted displays, personal computer displays, notebook computers, car navigation systems, car dashboards, digital cameras, video cameras, external advertising boards, electro-optical boards, various medical devices, various inspection devices, refrigerators or washing machines, etc., and Internet of Things devices. Representative examples of the foldable display device described later include foldable smart phones, tablet PCs or notebook computers, but are not limited thereto.

[0112] The display device 10 may be substantially rectangular in plan. The display device 10 may be rectangular with right angles or rectangular with rounded corners in plan. The display device 10 may include four sides or edges. The display device 10 may include long sides and short sides.

[0113] The display device 10 may include one side and another side. At least one of the one side and the other side of the display device 10 may be a display side. In one embodiment, the display side may be located on one side of the display device 10, and may not display in the direction toward the other side. The following description is mainly based on this embodiment, but the display device may also be a two-sided display device that displays on both one side and the other side.

[0114] The display device 10 may be divided into a display area DPA for displaying an image or a video and a non-display area NDA arranged around the display area DPA, depending on whether display is performed on a plane.

[0115] The display area DPA may include a plurality of pixels. A pixel is a basic unit of a display screen. A pixel may include a red pixel, a green pixel, and a blue pixel, but is not limited thereto. A pixel may also include a white pixel. A plurality of pixels may be arranged alternately on a plane. For example, the pixels may be arranged in row and column directions, but is not limited thereto.

[0116] The non-display area NDA may be arranged around the display area DPA. The non-display area NDA may surround the display area DPA. In one embodiment, the display area DPA may be formed in a rectangular shape, and the non-display area NDA may be arranged around the four sides of the display area DPA, but is not limited thereto. A black matrix may be arranged in the non-display area NDA to prevent light emitted from adjacent pixels from leaking.

[0117] The display device 10 may be a foldable device. The display device 10 may include a folding area FDA that is folded based on a folding line FL. The folding area FDA may be a straight line extending in one direction on a plane. In the drawings, the folding area FDA is illustrated as extending in parallel with the short side of the display device 10, but it is not limited thereto, and the folding area FDA may also be parallel to the long side or inclined relative to the short side and the long side.

[0118] In one embodiment, the folding area FDA of the display device 10 may also be determined at a specific position. In the display device 10, the folding area FDA determined at a specific position may be one or more than two. In other embodiments, the folding area FDA may also be freely set in various areas in the display device 10 without being specified in its position.

[0119] With the folding area FDA as a reference, the display device 10 may be divided into a first non-folding area NFA1 and a second non-folding area NFA2. The first non-folding area NFA1 may be located on one side of the folding area FDA, and the second non-folding area NFA2 may be located on the other side of the folding area FDA. In the case where the folding area FDA is determined at a specific position, the first non-folding area NFA1 and the second non-folding area NFA2 may be specified as areas that do not constitute a fold. The specified first non-folding area NFA1 and the second non-folding area NFA2 may have the same width, respectively, but are not limited thereto. In the case where the folding area FDA is not specified, the first non-folding area NFA1 and the second non-folding area NFA2 may have different areas depending on the position of the set folding area FDA.

[0120] The display area DPA of the display device 10 can be configured in the entire first non-folding area NFA1 and the entire second non-folding area NFA2. Furthermore, the display area DPA can also be located in the folding area FDA which is equivalent to the boundary between the first non-folding area NFA1 and the second non-folding area NFA2. That is, the display area DPA of the display device 10 can be continuously configured regardless of the boundaries of the non-folding areas NFA1, NFA2, the folding area FDA, etc. However, it is not limited to this, and the display area DPA may be configured in the first non-folding area NFA1 but not in the second non-folding area NFA2, or the display area DPA may be configured in the first non-folding area NFA1 and the second non-folding area NFA2 but not in the folding area FDA.

[0121] In one embodiment, the folding area FDA of the display device 10 may be an area corresponding to the thin portion SP of the cover window 100, and the non-folding areas NFA1 and NFA2 may be areas corresponding to the non-slim portions NSP1 and NSP2 of the cover window 100, respectively. When the display device 10 is folded, the folding area FDA may be folded based on the folding line FL, but the non-folding areas NFA1 and NFA2 are not folded. Since the thin portion SP is located in the folding area FDA, the stress generated during folding can be well resisted, and since the non-slim portions NSP1 and NSP2 are located in the non-folding areas NFA1 and NFA2, the durability against external impact can be excellent. In addition, the display device 10 includes the cover window 100 manufactured by the manufacturing method of the cover window 100 according to one embodiment, so that the boundary between the thin portion SP and the non-slim portions NSP1 and NSP2 or the boundary between the folding area FDA and the non-folding areas NFA1 and NFA2 can be prevented from being recognized from the outside.

[0122] The display device 10 can be folded in an inner folding manner in which the display surface faces inward and the display surfaces are folded in opposite directions, or in an outer folding manner in which the display surface faces outward. The display device 10 can be folded in only one of the inner folding manner and the outer folding manner, or both the inner folding and the outer folding can be realized. In the case of the display device 10 that realizes both the inner folding and the outer folding, the inner folding and the outer folding can be realized based on the same folding area FDA, or a plurality of folding areas FDA that perform folding in different ways from each other can be included, such as a folding line dedicated to the inner folding and a folding line dedicated to the outer folding.

[0123] In one embodiment, the display device 10 may be a display panel or a layer, panel, or substrate stacked on the display panel itself has a soft property, and the corresponding components are all folded to achieve folding. In some embodiments, at least a portion of the display panel or the components stacked on the display panel may have a shape separated based on the folding area FDA. In this case, the separated components located in the non-folding areas NFA1 and NFA2 may not have a soft property.

[0124] The display device 10 may include: a display panel 200 ; a cover window 100 disposed on the display panel 200 ; and a coupling member 300 disposed between the display panel 200 and the cover window 100 to couple the display panel 200 and the cover window 100 .

[0125] The display panel 200 may include not only self-luminous display panels such as an organic light-emitting display panel (OLED), an inorganic light-emitting display panel (inorganic EL), a quantum dot light-emitting display panel (QED), a micro-LED display panel (micro-LED), a nano-LED display panel (nano-LED), a plasma display panel (PDP), a field emission display panel (FED), and a cathode ray display panel (CRT), but may also include light-receiving display panels such as a liquid crystal display panel (LCD) and an electrophoretic display panel (EPD).

[0126] The display panel 200 may include a plurality of pixels PX, and use the light emitted from each pixel PX to display an image. The display device 10 may also include a touch component (not shown). In one embodiment, the touch component may be built into the display panel 200. For example, a touch component may be formed directly on the display component of the display panel 200, so that the display panel 200 itself performs a touch function. In other embodiments, the touch component may be attached to the upper surface of the display panel 200 through an optically transparent bonding layer after being manufactured separately from the display panel 200. The display panel 200 may include a side located in the front and another side located in the rear, and the light emitted from the pixel PX of the display panel 200 may be emitted toward the front. That is, the display panel 200 may display a picture toward the front.

[0127] Arranged on one side of the display panel 200 Figure 1 The cover window 100 is provided. The cover window 100 serves to protect the display panel 200. The cover window 100 is larger than the display panel 200, so its side surface may protrude further outward than the side surface of the display panel 200, but is not limited thereto. The cover window 100 may further include a printed layer disposed on at least one surface of the cover window 100 at an edge portion of the cover window 100. The printed layer of the cover window 100 prevents the frame area of ​​the display device 10 from being recognized from the outside, and may perform a decorative function according to circumstances.

[0128] A bonding component 300 is disposed between the display panel 200 and the cover window 100 or between one side of the display panel 200 and the second side LS2 of the cover window 100. The bonding component 300 serves to fix the cover window 100 to the display panel 200. The bonding component 300 may include an optically clear adhesive (OCA) or an optically clear resin (OCR).

[0129] The above embodiments of the present invention are described with reference to the accompanying drawings, but those skilled in the art should be able to understand that the present invention can be implemented in other specific forms without changing the technical concept or essential features of the present invention. Therefore, it should be understood that the embodiments described above are illustrative in all aspects and are not restrictive.

Claims

1. A method for manufacturing a cover window, comprising: The step of preparing a glass product having a flat upper surface; forming a concave portion in which a part of the upper surface of the glass product is recessed and forming a mask layer including water glass; as well as The step of wet-etching the mask layer and the glass product to form a cover window in which a portion of the upper surface is partially recessed.

2. The method for manufacturing a cover window according to claim 1, wherein: The step of forming the mask layer comprises: A step of coating a water glass layer on the upper surface of the glass product; and A step of etching a portion of the upper surface of the water glass layer to form the mask layer.

3. The method for manufacturing a cover window according to claim 2, wherein: The mask layer includes the concave portion and a flat portion connected to the concave portion and having a flat upper surface. The thickness of the concave portion is smaller than the thickness of the flat portion.

4. The method for manufacturing a cover window according to claim 3, wherein: The concave portion includes a first portion having a flat upper surface and a second portion connecting the first portion and the flat portion and having an inclined upper surface.

5. The method for manufacturing a cover window according to claim 3, wherein: The concave portion has a shape in which an upper surface is curved.

6. The method for manufacturing a cover window according to claim 1, wherein: In the step of forming the cover window, the mask layer is dissolved by an etching solution, and a portion of the upper surface of the glass product is etched.

7. The method for manufacturing a cover window according to claim 1, wherein: In the glass product, a portion of the mask layer corresponding to the concave portion is etched so that the upper surface has a curvature, and a portion corresponding to a region other than the concave portion is etched so that the upper surface is flat.

8. The method for manufacturing a cover window according to claim 1, wherein: The mask layer and the glass product are over-etched by wet etching.

9. The method for manufacturing a cover window according to claim 8, wherein: The maximum thickness of the cover window is less than the thickness of the glass product.

10. The method for manufacturing a cover window according to claim 1, wherein: The cover window comprises a first surface and a second surface which is opposite to the first surface and is flat. The cover window further includes a non-slim portion in which the first surface is flat, and a slim portion in which the first surface is partially recessed and has a thickness smaller than that of the non-slim portion.

11. The method for manufacturing a cover window according to claim 10, wherein: A portion of the first surface where the thin portion is located has a curved shape.

12. The method for manufacturing a cover window according to claim 10, wherein: The first thickness of the non-slim portion is in the range of 0.1 mm to 20 mm. The second thickness of the thin portion is in the range of 0.01 mm to 0.1 mm.

13. The method for manufacturing a cover window according to claim 12, wherein: The width of the thin portion is within a range of 20 mm or less.

14. The method for manufacturing a cover window according to claim 10, wherein: The cover window is folded with the folding line located at the thin portion as a reference so that the first surface faces inward.

15. A cover window, comprising a first surface and a second flat surface opposite to the first surface, and folded with a folding line as a reference so that the first surface faces inward, the cover window comprising: the flat non-slim portion of the first surface; as well as a slender portion, wherein the first surface is partially recessed and has a thickness smaller than that of the non-slender portion, and the folding line is located in the slender portion, The cover window is manufactured by wet-etching a glass product having a flat upper surface using a mask layer comprising water glass, and a portion of the upper surface of the mask layer is recessed to form a concave portion.

16. The cover window according to claim 15, wherein: The first thickness of the non-slim portion is in the range of 0.1 mm to 20 mm. The second thickness of the thin portion is in the range of 0.01 mm to 0.1 mm.

17. The cover window according to claim 16, wherein: The width of the thin portion is within a range of 20 mm or less.

18. The cover window according to claim 16, wherein: In a state where the first surface is folded based on the folding line, a length of the first surface measured from the narrow portion to a curvature radius is 2 mm.

19. A display device, which is an inwardly folding display device folded with a display surface facing inward, comprising: The display panel includes a surface located at the front and another surface located at the rear, and displays images toward the front; a cover window, arranged on the one side of the display panel, and comprising a first side and a second side opposite to the first side and flat; as well as a coupling member disposed between the second surface of the cover window and the display panel, The cover window includes a flat non-slim portion of the first surface and a slender portion of the first surface that is partially recessed and has a thickness smaller than that of the non-slender portion. The cover window is manufactured by wet-etching a glass product having a flat upper surface using a mask layer comprising water glass, and a portion of the upper surface of the mask layer is recessed to form a concave portion.

Images