| 摘要 |
<p>A translucent ceramic composed mainly of a composition of the general formula (1): Ba{M<SUB>x</SUB>B1<SUB>y</SUB>B2<SUB>z</SUB>}<SUB>v</SUB>O<SUB>w</SUB> (wherein B1 is a trivalent metal element; B2 is a pentavalent metal element; M is at least one member selected from among Ti, Sn, Zr and Hf; x+y+z=1, 0=x=0.45, 1.00=z/y=1.04 and 1.00=v=1.05; and w is a positive number required for maintaining electrical neutrality), or the general formula (2): Ba{M<SUB>x</SUB>(B1<SUB>s</SUB>B3<SUB>1-s</SUB>)<SUB>y</SUB>B2<SUB>z</SUB>}<SUB>v</SUB>O<SUB>w</SUB> (wherein B3 is a bivalent metal element; 0=x=0.9, 1.00=z/y=2.40 and 0<s<1; with respect to other parameters, the same as in the general formula (1)). This translucent ceramic exhibits high refractive index and high anomalous dispersion and excels in optical properties, so that it can be advantageously used as a material of objective lens (2) included in optical pickup (9).</p> |
