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KR-20260065612-A - Complex curved glass article and method of forming the same

KR20260065612AKR 20260065612 AKR20260065612 AKR 20260065612AKR-20260065612-A

Abstract

A reformed glass article having a shape that cannot be unfolded, and an associated mold and reforming technique are described. The glass article may be formed using a vacuum mold, which comprises a mold having a mold surface that defines a mold cavity. The mold may also comprise a frame comprising a body disposed on the mold, the body comprising a top surface comprising one or more vacuum openings formed on the top surface. The top surface comprises an outer edge, an inner edge, and a width (W) measured between the inner edge and the outer edge. The width (W) does not vary by more than 10% from the average value over the entire perimeter of the vacuum mold. The vacuum mold comprises a length (L) and a depth (D), the depth (D) being 10% to 30% of L. W is 0.06*L to 0.10*L. The reformed glass article may be reformed from a glass sheet to conform to the mold.

Inventors

  • 쿠브로 이베릭
  • 단누 티에리 뤽 알랭
  • 디디외 시릴 레미 앙드레
  • 미셸 케빈 로베르 클로드
  • 플레시에 장-마르크
  • 유 차오

Assignees

  • 코닝 인코포레이티드

Dates

Publication Date
20260508
Application Date
20240813
Priority Date
20230906

Claims (20)

  1. As a curved glass article in a molded state, First main surface; A second main surface positioned opposite to the first main surface; A minor surface extending between the first main surface and the second main surface; A peripheral region extending inward from the above-mentioned surface to a boundary region, wherein most of the peripheral region is substantially flat; A central curved surface area positioned inside the above boundary area; and It includes a length (L) representing the maximum linear distance between spaced points on the sub-surface measured in a first direction parallel to the first main surface in the surrounding area, and Within the above central curved surface region, the first principal surface includes a concave shape and the second principal surface includes a convex shape, and the first and second principal surfaces exhibit non-zero Gaussian curvature, The above curved glass article represents a maximum distance between a portion of the first main surface of the peripheral region and a portion of the first main surface of the central curved region in a second direction perpendicular to the first direction, i.e., a bending depth (DOB) expressed as 10% to 30% of the length, and The above-mentioned peripheral area includes a width measured parallel to the first main surface, and the width varies by 10% or less of the average value of the perimeter of the peripheral area, and A curved glass article in which the above-mentioned peripheral area exhibits one or fewer buckles along the entire outer periphery.
  2. In paragraph 1, 300 mm ≤ L ≤ 4000 mm, and Curved glass article having 50 mm ≤ DOB ≤ 700 mm.
  3. In paragraph 1 or 2, The above glass article is a curved glass article comprising a width (W) representing the maximum linear distance between spaced points on the sub-surface measured in a third direction parallel to the first main surface and perpendicular to the first direction in the surrounding area, wherein 200 mm ≤ W ≤ 2500 mm.
  4. In any one of paragraphs 1 through 3, The first principal surface of a portion of the central curved surface region comprises a surface area of 60,000 mm² or more, and A curved glass article, wherein, within the above portion, the thickness measured between the first main surface and the second main surface has a uniformity of +/- 75 microns per 1000 mm² of the surface area of the first main surface.
  5. In paragraph 4, A curved glass article comprising a non-developable curved shape, wherein the above portion includes a maximum compressive strain shape parameter of 3.0% or more and 10% or less, measured between a virtual center surface and a virtual surface disposed between the first main surface and the second main surface.
  6. In paragraph 4 or 5, A curved glass article, wherein, within the above portion, the average value of the thickness measured over the entire first main surface is 0.5 mm or more and 2.5 mm or less.
  7. As a vacuum mold, A mold having a complex non-developable shape and comprising a mold surface that defines a mold cavity; and A frame comprising a main body disposed on the mold, wherein the main body comprises an upper surface surrounding the perimeter of the mold surface and one or more vacuum openings formed on the upper surface, and the upper surface is: outer edge; As an inner edge, the inner edge, wherein the main body forms an interface with the mold; and It includes a width (W) measured in a first direction parallel to the top surface between the inner edge and the outer edge, The width (W) does not vary by more than 10% from the average value of the entire perimeter of the vacuum mold, and The above vacuum mold includes a length (L) representing the maximum linear distance between spaced points on the outer edge surface parallel to the top surface, and The vacuum mold comprises a depth (D) measured as the maximum vertical distance between the top surface and the mold surface in a direction perpendicular to the top surface, i.e., a depth (D) that is 10% to 30% of L, and A vacuum mold in which W is 0.06*L to 0.10*L.
  8. In Paragraph 7, A vacuum mold having an inner edge that includes a perimeter shape without a linear segment having a length longer than L/4.
  9. In paragraph 8, A vacuum mold in which the second derivative of the above perimeter shape is continuous over the entire shape.
  10. In paragraph 8, A vacuum mold in which the width (W) does not vary by more than 5% from the average value of the entire outer circumference of the vacuum mold.
  11. In any one of paragraphs 7 through 10, 300 mm ≤ L ≤ 4000 mm, and A vacuum mold with 50 mm ≤ D ≤ 700 mm.
  12. In any one of paragraphs 7 through 11, A vacuum mold, wherein the main body is formed of graphite, and the vacuum mold further comprises a metal frame disposed on the upper surface and around the outer edge.
  13. In Paragraph 12, A vacuum mold in which the inner edge of the metal frame is positioned outside one or more vacuum openings.
  14. In Paragraph 13, A vacuum mold further comprising a stainless steel mesh welded around the inner edge and disposed around the outer edge.
  15. As a method for forming curved glass articles, A step of placing a glass sheet on a vacuum mold comprising a mold surface that at least partially defines a vacuum cavity, wherein the glass sheet is placed on the vacuum mold and contacts the upper surface of a frame body surrounding the perimeter of the mold surface, and the upper surface is: One or more vacuum openings formed inside; outer edge; As an inner edge, the inner edge, wherein the main body forms an interface with the mold; and A step of placing a glass sheet on a vacuum mold, wherein the vacuum mold includes a width (W) measured parallel to the top surface between the inner edge and the outer edge, wherein the width (W) does not vary by more than 10% from the average value of the entire outer circumference of the vacuum mold, the vacuum mold includes a length (L) representing the maximum linear distance between spaced points on the outer edge measured parallel to the top surface, and the vacuum mold includes a depth (D) measured as the maximum vertical distance between the top surface and the mold surface in a second direction perpendicular to the top surface, i.e., a depth (D) that is 10% to 30% of L, and W is 0.06*L to 0.10*L; A step of heating the above glass sheet to a reshaping temperature; A step of applying vacuum pressure to one or more vacuum openings so that one or more first portions of the glass sheet are pulled into the one or more vacuum openings; and A method comprising the step of applying vacuum pressure to the vacuum cavity such that a second portion of the first glass sheet is pulled into the vacuum cavity and the glass sheet comes into contact with a portion of the mold surface that is positioned at the depth (D) relative to the top surface.
  16. In paragraph 15, A method in which, prior to the heating, the static friction coefficient between the top surface and the glass sheet is greater than 0.1 and less than or equal to 1.6.
  17. In paragraph 15 or 16, A method in which, when the glass sheet is placed on the upper surface, the entire peripheral edge of the glass sheet is aligned with the outer edge.
  18. In paragraph 15, A method in which, during the heating above, the first part is heated to a first temperature and the second part is heated to a second temperature lower than the first temperature.
  19. In Paragraph 18, The above second temperature is 20°C to 120°C lower than the above first temperature, method.
  20. In any one of paragraphs 15 through 19, The second portion of the glass sheet comprises an initial thickness (t1) before reshaping the glass sheet and a final thickness (t2) after reshaping the glass sheet, is a method in the range of 1.1 to 2.

Description

Complex curved glass article and method of forming the same Cross-reference regarding related applications This application claims the benefit of priority to U.S. provisional application serial number 63/536,763 filed on September 6, 2023, under 35 U.S.C. § 119, the contents of which form the basis and are incorporated herein by reference in their entirety. The present disclosure relates to vacuum forming of articles for use in various industries, e.g., consumer electronics, automobiles, home appliances, transportation, construction, defense, and medical. In particular, the present disclosure relates to vacuum forming of glass articles having an unexpandable shape and to the resulting vacuum-formed glass articles having an unexpandable shape. Many products include three-dimensional (3D) glass articles. Some examples of 3D glass articles include curved LCD or LED TV screens, smartphones, and windows. Innovations in product shapes pose new challenges to the manufacturing process for 3D parts, particularly those made of glass that must possess desirable scratch-resistant and impact-resistant properties along with excellent optical properties. Therefore, there is a continuing need for a method to manufacture three-dimensional articles with complex shapes and desirable optical and mechanical properties, particularly three-dimensional glass articles. The present disclosure relates to a vacuum forming apparatus and a method for forming a glass sheet into a curved glass article having a shape that is relatively difficult to obtain using a given conventional forming technique (e.g., an undevelopable shape and a bending depth of at least 200 mm). By using the apparatus and method described herein, a glass article of such a shape can be obtained while simultaneously exhibiting thickness uniformity and relatively low optical distortion compared to such conventional methods. In particular, a glass article formed through the method and apparatus described herein exhibits a relatively small amount of buckling due to the careful configuration of the frame supporting the periphery of the glass sheet during the forming process. Aspect (1) of the present disclosure relates to a curved glass article in a molded state, wherein the curved glass article comprises: a first main surface; a second main surface positioned opposite to the first main surface; a minor surface extending between the first main surface and the second main surface; a peripheral area extending inward from the minor surface to a boundary area, wherein most of the peripheral area is substantially flat; a central curved area positioned inside the boundary area; and includes a length (L) representing the maximum linear distance between spaced points on a subsurface measured in a first direction parallel to the first main surface within the surrounding area, wherein: within the central curved surface area, the first main surface has a concave shape and the second main surface has a convex shape and the first and second main surfaces have non-zero Gaussian curvature, and the curved glass article represents a bending depth (DOB) expressed as the maximum distance between a portion of the first main surface within the surrounding area measured in a second direction perpendicular to the first direction and a portion of the first main surface within the central curved surface area, the bending depth is 10% to 30% of the length, and the surrounding area includes a width measured parallel to the first main surface that varies by 10% or less of the average value of the periphery of the surrounding area, and the surrounding area represents one or fewer buckles over the entire outer periphery. An embodiment (2) of the present disclosure relates to a curved glass article according to embodiment (1), wherein: 400 mm ≤ L ≤ 4000 mm, and 50 mm ≤ DOB ≤ 700 mm. An embodiment (3) of the present disclosure relates to a curved glass article according to any one of embodiments (1) and (2), wherein the glass article comprises a width (W) representing the maximum linear distance between separated points on a subsurface, measured in a third direction parallel to a first main surface within a peripheral area and perpendicular to a first direction, wherein 200 mm ≤ W ≤ 2500 mm. An embodiment (4) of the present disclosure relates to a curved glass article according to any one of embodiments (1) to (3), wherein: in part of the central curved region, the first main surface comprises a surface area of 60,000 mm² or more, and in part, the thickness has a uniformity of +/- 75 microns per 1,000 mm² of the surface area of the first main surface. An embodiment (5) of the present disclosure relates to a curved glass article according to an embodiment (4), and includes a non-developable curved shape having a maximum compressive strain shape parameter of 3.0% or more and 10% or less, which is measured between a virtual center surface and a virtual surface disposed between a first main surface and a se