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

Abstract

To provide a peripheral surface-emitting linear light guide with a configuration that enables cost reduction while increasing the homogeneity of light intensity, and a method for manufacturing the peripheral surface-emitting linear light guide.SOLUTION: A peripheral surface-emitting linear light guide 3 comprises: an optical fiber 4 in which an outer peripheral surface 41a of a core 41 is exposed from a cladding 42 at one end in a longitudinal direction; and a light-scattering member 5 that covers an entire periphery of the outer peripheral surface 41a of the core 41 in an exposed portion over a predetermined axial length range. Light emitted from the outer peripheral surface 41a of the core 41 is scattered and radiated by the light-scattering member 5. The light-scattering member 5 includes a light transmissive base material 50 having a higher refractive index than the core 41, and light-scattering particles 500 that scatter the light incident on the base material 50, where the light-scattering particles 500 are dispersed and mixed in a certain proportion throughout the base material 50. At least a portion of the light-scattering member 5 in the longitudinal direction is a gradually increasing portion 51 whose thickness increases gradually toward a tip side of the core 41.SELECTED DRAWING: Figure 3

Claims

1. A circumferentially emitting linear light guide comprising an optical fiber in which the outer surface of the core is exposed from the cladding at one end in the longitudinal direction, and a light scattering member that covers the entire circumference of the exposed portion of the outer surface of the core over a predetermined axial length range, wherein light emitted from the outer surface of the core is scattered and radiated by the light scattering member, The light scattering member comprises a light-transmitting substrate with a refractive index higher than that of the core, and light-scattering particles that scatter light incident on the substrate, wherein the light-scattering particles are dispersed and mixed in a constant proportion throughout the substrate. At least a portion of the light scattering member in the longitudinal direction is a gradually increasing portion in which the thickness gradually increases toward the tip side of the core. The light scattering member has an annular thin-walled portion that is thinner than the thickest part of the gradually increasing portion, located on the tip side of the core than the gradually increasing portion. A linear light guide that emits light from its surrounding surface.

2. The outer circumferential surface of the aforementioned gradually increasing portion is a tapered surface formed without steps and inclined with respect to the central axis of the core. The peripheral surface emitting linear light guide according to claim 1.

3. The outer circumferential surface of the annular thin-walled portion is formed to be parallel to the central axis of the core. The peripheral surface emitting linear light guide according to claim 1.

4. A method for manufacturing a circumferentially emitting linear light guide according to any one of claims 1 to 3, A process for processing optical fibers to expose the outer surface of the core from the cladding, A preparation step of preparing a liquid body to be used as the light scattering member, An immersion step in which the exposed core is immersed in the liquid body over a predetermined axial length range, A lifting step in which the core and the liquid body are moved relative to each other in the vertical direction, thereby lifting the core from the liquid body, The process includes a curing step for hardening the liquid substance adhering to the core, When forming the gradually increasing portion of the light scattering member in the aforementioned pulling-up process, the pulling-up speed is changed to gradually increase the thickness of the liquid adhering to the outer surface of the core. A method for manufacturing a circumferentially emitting linear light guide.

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