Transparent member, electronic device including same, and thermoforming method of transparent member

A method comprising:

• inserting a first transparent substrate into a first cavity of a lower mold having a first depth and a second transparent substrate into a second cavity of the lower mold connected to the first cavity and having a second depth, wherein the second depth being greater than the first depth, wherein the first transparent substrate and the second transparent substrate are inserted in a solid state;
• positioning an upper mold on to the lower mold, wherein the upper mold corresponds to the lower mold and includes a pressing portion having at least one pressing surface;
• preheating at least one of the lower mold or the upper mold to a predetermined temperature, thereby resulting in preheated transparent substrates;
• and
• pressing the upper mold onto the lower mold, thereby thermoforming the preheated transparent substrates such that the first transparent substrate and the second transparent substrate are bonded to each other during the thermoforming, thereby forming thermoformed transparent substrates,
• wherein inserting the first transparent substrate and the second transparent substrate into the lower mold further comprises inserting the first transparent substrate and the second transparent substrate adjacent to each other, such that a gap is formed therebetween, and
• wherein the lower mold includes a first side wall, a second side wall facing the first side wall, a third side wall substantially perpendicular to the first side wall and second side wall, and a fourth side wall facing the third side wall,
• wherein the gap between the first transparent substrate and the second transparent substrate includes a first portion, a second portion closer to the fourth side wall of the lower mold than the first portion in a direction from the third side wall toward the fourth side wall, a third portion, and a fourth portion closer to the second side wall of the lower mold than the third portion in a direction from the first side wall toward the second side wall,
• wherein a second width of the second portion is greater than a first width of the first portion to prevent microbubbles being formed during thermos forming, and
• wherein a fourth width of the fourth portion is greater than a third width of the third portion to prevent microbubbles being formed during thermos forming.