Optical sensor

An optical sensor comprising:

• a support layer;
• a thermoelectric conversion material portion disposed on the support layer, the portion including a strip-shaped first material layer that converts thermal energy into electrical energy, and a strip-shaped second material layer that is electrically conductive;
• and
• a light absorbing film disposed on the thermoelectric conversion material portion to form a temperature difference in a longitudinal direction of the first material layer, the film converting received light into thermal energy;
• the first material layer including
• a first region including a first end located on one side in the longitudinal direction and
• a second region including a second end located on the other side in the longitudinal direction,
• the second material layer including
• a third region including a third end located on one side in a longitudinal direction and
• a fourth region including a fourth end located on the other side in the longitudinal direction, the fourth region being connected to the second region,
• the optical sensor further comprising:
• a first electrode electrically connected to the first region;
• and
• a second electrode disposed apart from the first electrode and electrically connected to the third region;
• the first material layer having a width, perpendicular to the longitudinal direction, of 0.1 μm or more,
• the first material layer including
• a thick portion located to include a center in a width direction of a cross section perpendicular to the longitudinal direction and
• thin portions located on both sides of the thick portion and smaller in thickness than the thick portion,
• the thick portion having a thickness of 10 nm or more,
• the thin portions having widths together accounting for 15% or more of the width of the first material layer,
• wherein the cross section of the first material layer perpendicular to the longitudinal direction includes
• a first side facing the support layer,
• a second side located apart from the first side in a thickness direction of the thick portion, and
• a pair of third sides connecting the first side and the second side,
• the cross section having a trapezoidal shape with the first side being greater in length than the second side, and
• wherein a relationship of 2≤tan θ×(w/d)≤10.7 exists in the cross section of the first material layer perpendicular to the longitudinal direction, where w represents the length of the first side, d represents the thickness of the thick portion, and θ represents an angle between the first side and each of the third sides.