Nikon Corporation

The University of Tokyo

Motoi Ueda

Kohei Yoshimoto

Tatsunori Kawashima

Hiroshi Yamamoto

Takeshi Hasegawa

Atsunobu Masuno

Yoshiro Oikawa

Hiroyuki Inoue

Tetsuo Hattori

Masaaki Kusano

Kiyoshi Numazaki

Mikio Okamoto

Kazufumi Ishibashi

Hideaki Shimomura

Naotaka Shimamura

Kiyoaki Shinohara

Takashi Ozawa

An optical glass includes, in terms of mol % of cations, a total amount of La, Y, and Gdcomponents falling within a range of from 5% to 65% and a total amount of Zr, Hf, and Tacomponents falling within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied. (La+Y+Gd)×(Zr+Hf+Ta)≥400(%).

Optical glass, optical element composed of optical glass, optical system interchangeable lens, and optical device

Provided is optical glass containing, in terms of mol % of cations: 10 to 60% of a Lacomponent; more than 0% and up to 75% of a Gacomponent; and 5 to 75% of a Nbcomponent, in which a total amount of the Lacomponent, Gacomponent, and Nbcomponent is 60 to 100%.

Optical glass, optical element including optical glass, and optical apparatus

An optical glass includes, in terms of mol % of cations, a total amount of La, Y, and Gdcomponents falling within a range of from 5% to 65% and a total amount of Zr, Hf, and Tacomponents failing within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied. (La+Y+Gd)&#xd7;(ZrHf+Ta)&#x2265;400(%).

A glass composition comprising: (A) TeO(50-95 mol %); (B) BO(1-33 mol %); (C) ZnO (1-37 mol %); (D) BiO(1-18 mol %); (E) PO(0-15 mol %); (F) RO (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) TiO(0-13 mol %); (I) NbO(0-10 mol %); (J) TaO(0-13 mol %); (K) LO(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 PO, RO, MO, TiO, NbO, TaO, and LOdescribed in (E) to (K), respectively, is 0-15 mol %.

Glass composition and optical member and optical instrument using the same

Optical glass for polarizing optical system, production process therefor and polarizing beam splitter

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.

Projection type display apparatus

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:

Polarizing optical system

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.

Projection type display device

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.

Growing community of inventors

Naka, Japan

Motoi Ueda