An elastic member including a first region and a second region, wherein the first region is defined as a folding region, and the second region is defined as an unfolding region, wherein the elastic member includes a first direction defined as a width direction of the elastic member and a direction in which a folding axis extends;
- and a second direction defined as a longitudinal direction of the elastic member and perpendicular to the first direction, wherein the first region includes a hinge part and a first pattern part including a plurality of patterns spaced apart from the hinge part with a bridge part interposed therebetween and extending in the first direction, wherein the second region includes a second pattern part including a plurality of patterns extending in the first direction, wherein the plurality of patterns of the first pattern part are formed in a hole shape, wherein the plurality of patterns of the second pattern part are formed in a groove shape, wherein the first region includes a 1-1 region closer to the folding axis and a 1-2 region and a 1-3 region spaced apart in the second direction with the 1-1 region interposed therebetween and farther from the folding axis than the 1-1 region, wherein the patterns and the bridge part of the first pattern part are provided in each of the 1-1 region, the 1-2 region, and the 1-3 region, wherein a length in the first direction of the pattern provided in the 1-1 region is greater than a length in the first direction of the pattern provided in the 1-2 region and a length in the first direction of the pattern provided in the 1-3 region, wherein a width in the second direction of the pattern provided in the 1-1 region is greater than a width in the second direction of the pattern provided in the 1-2 region and a width in the second direction of the pattern provided in the 1-3 region, and wherein a number of bridge parts in the 1-1 region is smaller than a number of bridge parts in each of the 1-2 region and the 1-3 region, wherein the elastic member further includes a first end region and a second end region facing each other in the first direction, wherein the patterns formed in the 1-1 region include a first pattern disposed in a central region of the 1-1 region with respect to the folding axis, and a second pattern and a third pattern disposed in an outer region of the 1-1 region so as to be directly adjacent to the first pattern in the second direction, wherein the first pattern, the second pattern, and the third pattern are spaced apart from each other in the second direction, wherein a width of the first pattern in the second direction is greater than a width of each of the second pattern and the third pattern in the second direction, wherein the width of each of the first pattern, the second pattern, and the third pattern in the second direction is greater than a spacing in the second direction between the first pattern and the second pattern and a spacing in the second direction between the first pattern and the third pattern, wherein the hinge part includes at least one first hinge part formed in the 1-1 region, spaced apart from the first to third patterns, and having the first end region and the second end region opened, wherein the at least one first hinge part includes a 1-1 hinge part formed such that the first end region and the second end region are each opened between the first pattern and the first end region and between the first pattern and the second end region, a 1-2 hinge part formed such that the first end region and the second end region are each opened between the second pattern and the first end region and between the second pattern and the second end region, and a 1-3 hinge part formed such that the first end region and the second end region are each opened between the third pattern and the first end region and between the third pattern and the second end region, and wherein a length of the 1-1 hinge part in the first direction is greater than a length of the 1-2 hinge part in the first direction and a length of the 1-3 hinge part in the first direction.