Abstract: Provided is optical glass containing, in terms of mol % of cations: 10 to 60% of a La3+ component; more than 0% and up to 75% of a Ga3+ component; and 5 to 75% of a Nb5+ component, in which a total amount of the La3+ component, Ga3+ component, and Nb5+ component is 60 to 100%.

Abstract: An optical glass includes, in terms of mol % of cations, a total amount of La3+, Y3+, and Gd3+ components falling within a range of from 5% to 65% and a total amount of Zr4+, Hf4+, and Ta5+ components falling within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied.

Abstract: Provided is optical glass containing, in terms of mol % of cations: 10 to 60% of a La3+ component; more than 0% and up to 75% of a Ga3+ component; and 5 to 75% of a Nb5+ component, in which a total amount of the La3+ component, Ga3+ component, and Nb5+ component is 60 to 100%.

Abstract: An optical glass includes, in terms of mol % of cations, a total amount of La3+, Y3+, and Gd3+ components falling within a range of from 5% to 65% and a total amount of Zr4+, Hf4+, and Ta5+ components failing within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied. (La3++Y3++Gd3+)×(Zr4+ Hf4++Ta3+)?400(%)2.

Abstract: An optical glass includes, in terms of mol % of cations, a total amount of La3+, Y3+, and Gd3+ components falling within a range of from 5% to 65% and a total amount of Zr4+, Hf4+, and Ta5+ components failing within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied.

Abstract: Provided is optical glass containing, in terms of mol % of cations: 10 to 60% of a La3+ component; more than 0% and up to 75% of a Ga3+ component; and 5 to 75% of a Nb5+ component, in which a total amount of the La3+ component, Ga3+ component, and Nb5+ component is 60 to 100%.

Abstract: An exposure apparatus irradiates an exposure light beam EL in a state that a space KS, between predetermined optical elements LS1 and LS2 among a plurality of optical elements included in a projection optical system, is filled with a liquid LQ. When the exposure light beam EL is not irradiated during, for example, the maintenance or the like, the liquid LQ in the space KS is substituted by a functional fluid LK different from the liquid LQ. This makes it possible to reduce any influence exerted by the liquid LQ on the exposure apparatus.

Abstract: A glass composition comprising: (A) TeO2 (50-95 mol %); (B) B2O3 (1-33 mol %); (C) ZnO (1-37 mol %); (D) Bi2O3 (1-18 mol %); (E) P2O5 (0-15 mol %); (F) R2O (0-13 mol %), where R represents at least one element selected from the group consisting of Li, Na, and K; (G) MO (0-13 mol %), where M represents at least one element selected from the group consisting of Mg, Ca, Sr, and Ba; (H) TiO2 (0-13 mol %); (I) Nb2O5 (0-10 mol %); (J) Ta2O5 (0-13 mol %); (K) L2O3 (0-11 mol %), where L represents at least one element selected from the group consisting of yttrium and lanthanoids; and (L) the total amount of P2O5, R2O, MO, TiO2, Nb2O5, Ta2O5, and L2O3 described in (E) to (K), respectively, is 0-15 mol %.

Abstract: A glass composition satisfying the following conditions (A) to (L), the conditions are: (A) a content ratio of TeO2 is in a range from 50 to 95 mol %; (B) a content ratio of B2O3 is in a range from 1 to 33 mol %; (C) a content ratio of ZnO is in a range from 1 to 37 mol %; (D) a content ratio of Bi2O3 is in a range from 1 to 18 mol %; (E) a content ratio of P2O5 is in a range from 0 to 15 mol %; (F) a content ratio of R2O (where R represents at least one element selected from the group consisting of Li, Na, and K) is in a range from 0 to 13 mol %; (G) a content ratio of MO (where M represents at least one element selected from the group consisting of Mg, Ca, Sr, and Ba) is in a range from 0 to 13 mol %; (H) a content ratio of TiO2 is in a range from 0 to 13 mol %; (I) a content ratio of Nb2O5 is in a range from 0 to 10 mol %; (J) a content ratio of Ta2O5 is in a range from 0 to 13 mol %; (K) a content ratio of L2O3 (where L represents at least one element selected from the group consisting of yttrium and lant

Abstract: An exposure apparatus irradiates an exposure light beam a state that a space, between predetermined optical elements and among a plurality of optical elements included in a projection optical system, is filled with a liquid. When the exposure light beam is not irradiated during, for example, the maintenance or the like, the liquid in the space is substituted by a functional fluid different from the liquid. This makes it possible to reduce any influence exerted by the liquid on the exposure apparatus.

Abstract: An optical glass for polarizing optical system having a photoelastic constant C in the range of −0.2 to +0.

Abstract: An optical glass for polarizing optical system having a photoelastic constant C in the range of −0.2 to +0.5 [10−8 cm2/N] with respect to a wavelength of 633 nm, the optical glass having the following composition (1): composition (1): when represented in terms of wt. % of oxides: SiO2: 17.0-27.0% (35.5-57.0 mol %) Li2O+Na2O+K2O: 0.5-5.0% (0.7-20.0 mol %) PbO: 72.0-75.0% (39.1-45.0 mol %) As2O3+Sb2O3: 0.1-3.0% (0.1-2.0 mol %).

Abstract: The present invention relates to a projection type display apparatus which utilizes a polarizing beam splitter and/or a color separating/combining optical system, each being constituted by an optically transparent material block having a specific characteristic, thereby being capable of securing optically stable performances against influences of various thermal and external stresses and suppressing image quality deterioration to a low level. In particular, in this projection type display apparatus, the polarizing beam splitter used for a polarized light separating optical system and analyzing optical system, and/or an optical member servicing as a color separating/combining optical system are constituted by an optically transparent material block in which a wavelength where the absolute value of a photoelastic constant becomes a minimum level exists in a wavelength range of a blue light component.

Abstract: A polarizing optical system comprising: at least, polarizing characteristic imparting means for imparting a polarizing characteristic to light emitted from a light source; analyzer means for converting the polarizing characteristic into light intensity information; and output means for outputting the light intensity information; at least one element constituting the polarizing characteristic imparting means comprising an optical glass having a photoelastic constant C in the range of substantially zero with respect to a wavelength range of 0.4 .mu.m to 3.0 .mu.m. The optical glass has a photoelastic constant C in the range of -0.8 to +0.8 (10.sup.-8 cm.sup.2 /N) with respect to a wavelength range of 0.4 .mu.m to 3.0 .mu.m, and has the following composition when represented in terms of wt.% of oxides:SiO.sub.2 : 17.0-27.0% (35.5-57.0 mol %)Li.sub.2 O+Na.sub.2 O+K.sub.2 O: 0.5-5.0% (0.7-20.0 mol %)PbO: 72.0-75.0% (39.1-45.0 mol %)As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 : 0-3.0% (0.0-2.

Abstract: A color projection display device separates light into the colors of red, green and blue. Each of the color components is modulated, superimposed with the other components again and projected. The device provides color picture images with few irregularities in illumination intensity. Polarizing beam splitters used for modulation of the colors are constructed from base materials having a minimum absolute photoelasticity constant value at different wavelengths. Thus, the absolute photoelasticity constant value of the base material for a particular wavelength of light that is separated by the polarizing beam splitter can be made small and double refractions, resulting from stress, are unlikely to occur in any of the components. As a result, a disturbance in the polarization and separation performance is unlikely to occur, and irregularities in the illumination intensity can be reduced.

Abstract: A projection type display apparatus includes a spatial light modulator, a polarizing beam splitter formed of members of a transparent material, and a projection optical system. The polarizing beam splitter includes a dielectric multilayer film, and a first transparent material member and a second transparent material member sandwiching the dielectric multilayer film. Each of the first and second transparent material members is made of a transparent material with a refractive index of at least 1.8 and with an absolute value of the photoelastic constant being no more than 1.5.times.10.sup.-8 cm.sup.2 /N for light of wavelengths 0.4 .mu.m to 0.7 .mu.m, incident to the polarizing beam splitter.