Touch sensor

1. A touch sensor with a view area, the touch sensor comprising:

a substrate with a first surface; and

a plurality of first electrodes on the first surface of the substrate in the view area, wherein:

the first surface of the substrate includes a plurality of bottomed grooves extending linearly,

each of the plurality of first electrodes includes a plurality of fine lines,

each of the plurality of fine lines includes a conductive material buried in one of the plurality of grooves,

at least one of the plurality of fine lines includes a recess recessed from the first surface toward a bottom surface of each of the plurality of grooves,

each of bottom and side surfaces of the recess are curved, an entirety of which forms a concave shape, and

each of the side surfaces of the recess is entirely curved from an opening edge of the recess to a connection point to the bottom surface so as to form a concave shape.

2. The touch sensor of claim 1 , wherein

a distance along a plane direction of the substrate between each of side surfaces of the groove and a corresponding one of the side surfaces of the recess becomes gradually greater in a thickness direction of the substrate from the opening edge of the recess toward the bottom surface of the recess.

3. The touch sensor of claim 1 , wherein

the bottom surface of the recess has a smaller radius of curvature than the side surface of the recess.

4. The touch sensor of claim 1 , wherein

an opening width of the recess orthogonal to an extending direction thereof is larger than a size corresponding to one-fourth of a width of the plurality of grooves orthogonal to an extending direction thereof.

5. The touch sensor of claim 1 , wherein

a blackened layer serves as an overlying layer of at least the recess.