Method and apparatus for forming glass laminates comprising plies with offset edges
Methods and apparatuses for fabricating glass laminates where there is a substantial offset between edges of glass plies of the laminates are described herein. The method includes placing an entirety of the periphery of a stack of the glass plies in a vacuum ring comprising a vacuum channel with a depth that circumferentially varies. The vacuum ring includes at least a first portion where the vacuum channel has a first depth and a second portion where the vacuum channel has a second depth that is at least two times greater than the first depth to accommodate edge offsets. Negative pressure can be applied to a space between the plies via the vacuum ring to deair the space. A suitable furnace can be used to bond the plies together and form a laminate having a desired shape.
1 . A process for fabricating a glass laminate, the process comprising:
positioning a second glass substrate onto a first glass substrate with a polymeric material between the first glass substrate and the second glass substrate to form a stack, wherein the first glass substrate comprises a greater surface area than the second glass substrate such that the first substrate comprises an extending portion that is not covered by the second glass substrate and an edge of the first glass substrate is offset from an edge of the second glass substrate by a distance that is greater than or equal to 10 mm;
inserting an entirety of a periphery of the stack into a vacuum channel of a vacuum ring, wherein the vacuum ring comprises a first portion where the vacuum channel has a first depth and a second portion where the vacuum channel has a second depth that is greater than or equal to twice the first depth, wherein an entirety of the extending portion is contained in the second portion of the vacuum ring;
applying negative pressure to the vacuum channel; and
heating the stack to above a softening temperature of the polymer material to bond the first glass substrate to the second glass substrate such that the second glass substrate is retained in a bent shape by the first glass substrate and the polymer material.
2 . The process of claim 1 , wherein the distance that the edge of the first glass substrate is offset from the edge of the second glass substrate varies as a function of position within the stack.
3 . The process of claim 1 , wherein the distance comprises a maximum value that is greater than or equal to 100 mm.
4 . The process of claim 3 , wherein the second depth is greater than or equal to 100 mm.
5 . The process of claim 1 , wherein, within the second portion, the second depth has a constant value.
6 . The process of claim 1 , wherein:
the periphery comprises an aligned portion where three edges of the second glass substrate are aligned with three corresponding edges of the first glass substrate, and
the first portion of the vacuum ring encapsulates an entirety of the aligned portion of the periphery.
7 . The process of claim 1 , wherein the vacuum channel comprises a constant width measured in a direction perpendicular to the depth.
8 . The process of claim 7 , wherein the constant width is less than or equal to a total thickness of the glass laminate.
9 . The process of claim 1 , further comprising applying a force to the stack to press the first glass substrate against the second glass substrate, wherein applying the force comprises contacting the second glass substrate with a pressing member to press the second glass substrate against the first glass substrate.
10 . The process of claim 1 , wherein the extending portion comprises one or more openings.
11 . The process of claim 1 , wherein the first glass substrate is curved, and, when the stack is formed, the second glass substrate comprises a minimum radius of curvature that is greater than that of the first glass substrate, wherein applying the negative pressure causes the second glass substrate to bend.