A glass frit includes Bi.sub.2O.sub.3 and has a glass transition temperature (Tg) in a range of 280° C. to 320° C. A display device includes the glass frit including Bi.sub.2O.sub.3 and the glass transition temperature (Tg) in the range of 280° C. to 320° C. The display device shows excellent internal reliability and drop strength.

Provided is an optical glass containing glass-forming cations, the optical glass satisfying, expressed in cation percent, 10 cat %≤B.sup.3+≤50 cat %, 15 cat %≤La.sup.3+≤35 cat %, 20 cat %≤Nb.sup.5+≤50 cat %, and 15 cat %≤Ti.sup.4+≤25 cat %.

Provided is an optical glass containing glass-forming cations, the optical glass satisfying, expressed in cation percent, 10 cat %≤B.sup.3+≤50 cat %, 15 cat %≤La.sup.3+≤35 cat %, 20 cat %≤Nb.sup.5+≤50 cat %, and 15 cat %≤Ti.sup.4+≤25 cat %.

Provided is an optical glass containing glass-forming cations, the optical glass satisfying, expressed in cation percent, 10 cat %B.sup.3+50 cat %, 15 cat %La.sup.3+35 cat %, 20 cat %Nb.sup.5+50 cat %, and 15 cat %Ti.sup.4+25 cat %.

Provided is an optical glass containing glass-forming cations, the optical glass satisfying, expressed in cation percent, 10 cat %B.sup.3+50 cat %, 15 cat %La.sup.3+35 cat %, 20 cat %Nb.sup.5+50 cat %, and 15 cat %Ti.sup.4+25 cat %.

Disclosed are an optical glass, a glass preform, an optical element and an optical instrument having the same. The optical glass comprises 5 to 25 wt % of B.sub.2O.sub.3, 25 to 45 wt % of La.sub.2O.sub.3, 0 to 10 Wt % of Y.sub.2O.sub.3, 10 to 35 wt % of Gd.sub.2O.sub.3, 0.5 to 15 wt % of SiO.sub.2, 1 to 15 wt % of ZrO.sub.2, 0 to 5 wt % of TiO.sub.2, 0 to 7 wt % of WO.sub.3, 0 to 15 wt % of Ta.sub.2O.sub.5, 0 to 10 wt % of ZnO and 0 to 8.5 wt % of Nb.sub.2O.sub.5; and m.sub.(B2O3+SiO2+ZrO2+Nb2O5+TiO2+WO3)/m.sub.(La2O3+ZrO2) is not lower than 0.6.

A method for manufacturing a glass wafer for augmented reality applications includes the steps of: providing the raw wafer; edge-grinding of the raw wafer; lapping the raw wafer; rough polishing the raw wafer; fine polishing the raw wafer to obtain an intermediate wafer; gluing the intermediate wafer on a flat carrier; performing single-side polishing of a first main side of the intermediate wafer; and performing single-side polishing of a second main side of the intermediate wafer.

A method for manufacturing a glass wafer for augmented reality applications includes the steps of: providing the raw wafer; edge-grinding of the raw wafer; lapping the raw wafer; rough polishing the raw wafer; fine polishing the raw wafer to obtain an intermediate wafer; gluing the intermediate wafer on a flat carrier; performing single-side polishing of a first main side of the intermediate wafer; and performing single-side polishing of a second main side of the intermediate wafer.

The purpose of the present invention is to provide a neutron-absorbing material which has high neutron absorption performance, is less apt to suffer structural degradation caused by irradiation with neutrons or rays, and has satisfactory water resistance. The glass composition according to the present invention is characterized by containing Gd2O3, B2O3, CeO2, and Bi2O3 when the components are expressed in terms of oxide, the total amount of Gd2O3 and B2O3 being 65 mol % or greater in terms of oxide amount.

The purpose of the present invention is to provide a neutron-absorbing material which has high neutron absorption performance, is less apt to suffer structural degradation caused by irradiation with neutrons or rays, and has satisfactory water resistance. The glass composition according to the present invention is characterized by containing Gd2O3, B2O3, CeO2, and Bi2O3 when the components are expressed in terms of oxide, the total amount of Gd2O3 and B2O3 being 65 mol % or greater in terms of oxide amount.