Abstract: An optical glass is provided which does not contain components negatively affecting the environment as environmental loads, and is less colored while having a refractive index maintained moderately high. The optical glass has a composition including, in % by mass, 30% or more and 47% or less of SiO2, 0% or more and 10% or less of B2O3, 3% or more and 12% or less of Na2O, 0% or more and 5% or less of Li2O, 0% or more and 3.8% or less of CaO, 28% or more and 43% or less of BaO, 3% or more and 16% or less of ZnO, 0% or more and 8% or less of ZrO2, 0% or more and 15% or less of La2O3, where Sb2O3 is excluded from the composition, wherein the optical glass does not contain any of PbO, As2O3, and K2O.

Abstract: Provided is an optical fiber illumination device in which optical fibers produced without using a special method is used and the amount of light emitted from the side surface is improved. An optical fiber illumination device 1 includes: an optical fiber bundle 10 having a plurality of optical fibers, a resin jacket 101 that covers a bundle of the plurality of optical fibers and emits light, a first end, and a second end, the first end and the second end being polished; and a first light source placed close to the first end so as to emit light in a range of angles larger than an angular aperture of the plurality of optical fibers toward the optical fiber bundle.

Abstract: Provided is an optical fiber illumination device in which optical fibers produced without using a special method is used and the amount of light emitted from the side surface is improved. An optical fiber illumination device 1 includes: an optical fiber bundle 10 having a plurality of optical fibers, a resin jacket 101 that covers a bundle of the plurality of optical fibers and emits light, a first end, and a second end, the first end and the second end being polished; and a first light source placed close to the first end so as to emit light in a range of angles larger than an angular aperture of the plurality of optical fibers toward the optical fiber bundle.

Abstract: An optical glass is provided which does not contain components negatively affecting the environment as environmental loads, and is less colored while having a refractive index maintained moderately high. The optical glass has a composition including, in % by mass, 30% or more and 47% or less of SiO2, 0% or more and 10% or less of B2O3, 3% or more and 12% or less of Na2O, 0% or more and 5% or less of Li2O, 0% or more and 3.8% or less of CaO, 28% or more and 43% or less of BaO, 3% or more and 16% or less of ZnO, 0% or more and 8% or less of ZrO2, 0% or more and 15% or less of La2O3, where Sb2O3 is excluded from the composition, wherein the optical glass does not contain any of PbO, As2O3, and K2O.

Abstract: Provided is an image guide fiber that improves image quality while preventing a manufacturing problem. The image guide fiber according to the present disclosure has a numerical aperture NA in the range of 0.70 to 0.90. A linear thermal expansion coefficient difference ??, which is a value obtained by subtracting a linear thermal expansion coefficient ?2 at from 100 to 300° C. of clad glass, from a linear thermal expansion coefficient ?1 at from 100 to 300° C. of core glass, is in the range of ?3×10?7° C. to 15×10?7/° C. A glass-transition temperature Tg1 of the core glass is higher than a glass-transition temperature Tg2 of the clad glass. A core occupancy area ratio is 25% or more. A pixel density is 0.1 pixel/?m2 or more.

Abstract: Provided is an image guide fiber that improves image quality while preventing a manufacturing problem. The image guide fiber according to the present disclosure has a numerical aperture NA in the range of 0.70 to 0.90. A linear thermal expansion coefficient difference ??, which is a value obtained by subtracting a linear thermal expansion coefficient ?2 at from 100 to 300° C. of clad glass, from a linear thermal expansion coefficient ?1 at from 100 to 300° C. of core glass, is in the range of ?3×10?7/° C. to 15×10?7/° C. A glass-transition temperature Tg1 of the core glass is higher than a glass-transition temperature Tg2 of the clad glass. A core occupancy area ratio is 25% or more. A pixel density is 0.1 pixel/?m2 or more.

Abstract: A glass material is provided which is capable of exhibiting fluorescence in the visible region by ultraviolet ray excitation. This glass material is represented, in term of atoms for making up the glass, by the following chemical composition (mol %):______________________________________ SiO.sub.2 2 to 60%, B.sub.2 O.sub.3 5 to 70% (SiO.sub.2 + B.sub.2 O.sub.3 = 50 to 70%) RO 5 to 30% (R: at least one atom selected from Mg, Ca, Sr and Ba) ZnO 0 to 15% ZrO.sub.2 0 to 10%, Tb.sub.2 O.sub.3 or Eu.sub.2 O.sub.3 2 to 15% (containing either of Tb.sub.2 O.sub.3 or Eu.sub.2 O.sub.3) Ln.sub.2 O.sub.3 0 to 20% (Ln: at least one atom selected from Y, La, Gd, Yb, Lu, Sm, Dy and Tm) CeO.sub.2 0 to 1% Bi.sub.2 O.sub.3 0 to 2% Sb.sub.2 O.sub.3 0.01 to 0.5% and R'.sub.

Abstract: A drive control commanding unit is provided which, when plural such units constitute a system, can configure the system as a synchronous system which can conduct a synchronous operation free from synchronism deviation. The drive control commanding unit has an operation clock generator 9 which generates an operation clock signal, an interruption generator 11 which outputs an interruption signal at every cycle of the operation clock signal.