Window for display apparatus, manufacturing method thereof, and manufacturing method of display apparatus
A method of manufacturing a window for a display apparatus according to the present invention includes: providing, on a stage, a substrate including a foldable part bending around a folding axis extending in a first direction, and forming a groove on the foldable part. The forming the groove includes: grinding the foldable part by using a first machining wheel; grinding the foldable part by using a second machining wheel; and machining the foldable part by using a polishing wheel. The groove has at least one radius of curvature. The first machining wheel includes first abrasive grains, and the second machining wheel includes second abrasive grains less in size than the first abrasive grains.
1. A window for a display apparatus comprising:
a foldable part bent along a first direction; and
a flat part adjacent to the foldable part,
wherein the foldable part comprises a groove surface providing a groove having a plurality of radii of curvature defined in a plane perpendicular to the first direction, the groove surface comprises one end contacting the flat part, an other end contacting the flat part and facing the one end, and an internal point between the one end and the other end, and each of the one end, the other end and the internal point has a minimum radius of curvature among the plurality of radii of curvature, and
a width of the groove surface in a second direction intersecting the first direction is defined as L 1 , the maximum depth of the groove is defined as d 1 , a thickness of the flat part is defined as h 1 , and the minimum radius of curvature is defined as RR, wherein
RR is 2 m to 10 m inclusive,
d 1 is 0.01 mm to 0.05 mm inclusive,
RR×(d 1 /L 1 2 ) is 0.08 to 0.12 inclusive, and
RR×(d 1 /L 1 /h 1 ) is 10 to 50 inclusive.
2. The window of claim 1 , wherein the internal point comprises a first internal point and a second internal point spaced apart from the first internal point in a second direction intersecting the first direction, and
each of the first internal point and the second internal point has the minimum radius of curvature.
3. The window of claim 2 , wherein the groove surface corresponding to a line between the first internal point and the second internal point is flat.
4. The window of claim 1 , wherein the flat part comprises a first flat part and a second flat part, and
the foldable part is disposed between the first flat part and the second flat part.
5. The window of claim 1 , wherein in a thickness direction of the flat part, a thickness of the flat part is greater than that of the groove.
6. The window of claim 1 , wherein the flat part comprises an upper surface and a bottom surface facing the upper surface, and
the groove surface has a shape recessed from the upper surface of the flat part.