Peripheral surface-emitting linear light guide and method for manufacturing the same

A peripheral surface-emitting linear light guide, comprising:

• an optical fiber including a core, an outer peripheral surface of which is exposed from a cladding at one end in a longitudinal direction;
• and
• a light-scattering member that covers an entire periphery of the outer peripheral surface of the core in an exposed portion over a predetermined axial length range,
• wherein light emitted from the outer peripheral surface of the core is scattered and radiated by the light-scattering member,
• wherein the light-scattering member comprises a light transmissive base material having a higher refractive index than the core and light-scattering particles that scatter the light incident on the base material, and the light-scattering particles are dispersed and mixed in a certain proportion throughout the base material,
• wherein at least a portion of the light-scattering member in the longitudinal direction is an incremental portion whose thickness increases gradually toward a tip side of the core, and
• wherein the light-scattering member further comprises, on the tip side of the core from the incremental portion, an annular thin-walled portion which is thinner than a thickest portion of the incremental portion.