Light detection unit

A light detection unit connected to an optical sensor, which includes:

• a light emitting element that projects detection light toward a detection area;
• a light receiving element that receives the detection light from the detection area;
• and
• a signal generation unit that compares a light reception signal generated by the light receiving element with a threshold and generates a detection signal indicating a comparison result,
• the light detection unit comprising:
• an optical waveguide that guides light between a first end and a second end, has a sheet shape which is wide in a horizontal direction, has a core and a cladding surrounding the core, and projects light to the detection area or receives light from the detection area, the core and the cladding being provided in layers in a vertical direction, the first end connected to a light projection connecting section or a light reception connecting section so as to be optically coupled to the light emitting element or the light receiving element of the optical sensor, the second end being used as a light projecting end or a light receiving end;
• and
• a sheet-shaped cover member that covers the cladding in a vicinity of the second end of the optical waveguide or between the first end and the second end and is integrally formed with the optical waveguide.