Patent ID: 8758239

Claim:
A biological information detector, comprising: a light-emitting part configured to emit a first light directed at a detection site of a test subject and a second light directed in a direction other than a direction of the detection site; a first reflecting part configured to be disposed on a substrate and to reflect the second light and directing the second light towards the detection site, wherein the first reflecting part is disposed by a predetermined distance projecting from the light-emitting part toward the detection site; and a light-receiving part configured to be disposed on the substrate and to receive light having biological information, the light produced by the first light and the second light being reflected at the detection site, wherein an equation W 1 ≦W 2 is satisfied, when in a cross-sectional view, W 1 is a maximum value for the length of the first reflecting part in a direction parallel to a first surface of the substrate, and W 2 is a maximum value for the length of the light-receiving part in the direction parallel to the first surface.