A touch panel includes a transparent plate, an upper substrate having an upper surface situated on a lower surface of the transparent plate and stacked on the transparent plate in a downward direction, an upper conductive layer provided between the lower surface of the transparent plate and the lower surface of the upper substrate, a lower substrate having an upper surface situated on the lower surface of the upper substrate and stacked on the upper substrate in the downward direction, and a lower conductive layer provided between the lower surface of the upper substrate and the upper surface of the lower substrate and facing the upper conductive layer across the upper substrate. The upper surface of the transparent plate has a dome shape projecting upward on a cross section in a first direction perpendicular to the downward direction and on a cross section in a second direction perpendicular to the downward direction and the first direction. The lower surface of the transparent plate is concave upward on the cross section in the first direction is straight on the cross section in the second direction. The touch panel can be easily manufactured and reliably operated.
1. A touch panel comprising:
a transparent plate having an upper surface and a lower surface;
an upper substrate having a lower surface and an upper surface which is situated on the lower surface of the transparent plate, the upper substrate being stacked on the transparent plate in a downward direction;
an upper conductive layer provided between the lower surface of the transparent plate and the lower surface of the upper substrate;
a lower substrate having an upper surface situated on the lower surface of the upper substrate, the lower substrate being stacked on the upper substrate in the downward direction; and
a lower conductive layer provided between the lower surface of the upper substrate and the upper surface of the lower substrate, the lower conductive layer facing the upper conductive layer across the upper substrate,
wherein the upper surface of the transparent plate has a dome shape projecting upward on a cross section in a first direction perpendicular to the downward direction and on a cross section in a second direction perpendicular to the downward direction and the first direction, and
wherein the lower surface of the transparent plate is concave upward on the cross section in the first direction and is straight on the cross section in the second direction.
2. The touch panel according to claim 1 , wherein the lower surface of the transparent plate substantially has a cylindrical surface shape.
3. The touch panel according to claim 1 , wherein the transparent plate substantially has a rectangular shape having short sides and long sides longer than the short sides, the short sides extending in the first direction, the second sides extending in the second direction.
4. The touch panel according to claim 1 , wherein the transparent plate has a uniform thickness on the cross section of the transparent plate in the first direction.
5. The touch panel according to claim 1 , wherein a curvature radius of the upper surface of the transparent plate on the cross section in the first direction is smaller than a curvature radius of the upper surface of the transparent plate on the cross section in the second direction.
6. The touch panel according to claim 1 , wherein a curvature radius of the lower surface of the transparent plate on the cross section in the first direction is substantially identical to the curvature radius of the upper surface of the transparent plate on the cross section in the first direction.
7. The touch panel according to claim 6 , wherein a thickness of the transparent plate in the first direction is substantially constant.
8. The touch panel according to claim 1 , wherein a thickness of the transparent plate in the first direction is substantially constant.