Abstract: A frame has an outer frame made of microcellular foam resin, and two inner frames made of the microcellular foam resin. The two inner frames are arranged together inside the outer frame. Both of the inner frames and the outer frame include openings provided at respective upper portions and recess portions formed downwardly from the openings, respectively. An LED light source, which is arranged inside a light guide space, emits light with a light emitting face thereof directing toward the light guide space. Accordingly, light from the LED light source is uniformly emitted from a light extraction portion. Also, an LED light source arranged inside a light guide space emits light directing toward the light guide space. Accordingly, light from the LED light source is uniformly emitted from a light extraction portion.

Abstract: A frame has an outer frame made of microcellular foam resin, and two inner frames made of the microcellular foam resin. The two inner frames are arranged together inside the outer frame. Both of the inner frames and the outer frame include openings provided at respective upper portions and recess portions formed downwardly from the openings, respectively. An LED light source, which is arranged inside a light guide space, emits light with a light emitting face thereof directing toward the light guide space. Accordingly, light from the LED light source is uniformly emitted from a light extraction portion. Also, an LED light source arranged inside a light guide space emits light directing toward the light guide space. Accordingly, light from the LED light source is uniformly emitted from a light extraction portion.

Abstract: An optical fiber made of quartz or glass and having a core and a cladding includes a microporous silica solution applied to an outer peripheral surface thereof, which is synthesized from a mixture of silicon alcoxide, active alcohol for facilitating hydrolytic action, alcohol, and water, by means of the sol-gel process, followed by baking to form a thin film of microporous silica made chiefly of silicon. Microporous of the thin film of microporous silica have function of cushioning to cushion and restrain that micro cracks much existing in the cladding undergo growth when the optical fiber is bent so that the optical fiber is likely to be broken. And the thin film of microporous silica which made chiefly of silicon has high heat-resistant properties similarly to the optical fiber itself. Accordingly, a heat-resistant optical fiber very excellent in heat-resistant properties is provided.

Abstract: To the outer peripheral surface of an optical fiber made of quartz or glass and having a core and a cladding is applied a microporous silica solution, which is synthesized from a mixture of silicon alcoxide, active alcohol for facilitating hydrolytic action, alcohol, and water, by means of the sol-gel process, followed by baking to form a thin film of microporous silica made chiefly of silicon. Microporous of the thin film of microporous silica have function of cushioning to cushion and restrain that micro cracks much existing in the cladding undergo growth when the optical fiber is bent so that the optical fiber is likely to be broken. And the thin film of microporous silica which made chiefly of silicon has high heat-resistant properties similarly to the optical fiber itself. Accordingly, a heat-resistant optical fiber very excellent in heat-resistant properties is provided.

Abstract: To the outer peripheral surface of an optical fiber made of quartz or glass and having a core and a cladding is applied a microporous silica solution, which is synthesized from a mixture of silicon alcoxide, active alcohol for facilitating hydrolytic action, alcohol, and water, by means of the sol-gel process, followed by baking to form a thin film of microporous silica made chiefly of silicon. Microporous of the thin film of microporous silica have function of cushioning to cushion and restrain that micro cracks much existing in the cladding undergo growth when the optical fiber is bent so that the optical fiber is likely to be broken. And the thin film of microporous silica which made chiefly of silicon has high heat-resistant properties similarly to the optical fiber itself. Accordingly, a heat-resistant optical fiber very excellent in heat-resistant properties is provided.