Nikon Corporation

Kabushiki Kaisha Toyota Chuo Kenkyusho

Mikio Okamoto

Tetsuo Hattori

Masatoshi Sato

Takeshi Hasegawa

Tomoyoshi Motohiro

Yasuhiko Takeda

Tatsumi Hioki

Shoji Noda

Motoi Ueda

Yoshiro Oikawa

Hiroshi Niikura

Naotaka Shimamura

An optical glass for polarizing optical system having a photoelastic constant C in the range of &#x2212;0.2 to +0.5 [10cm/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:SiO: 17.0&#x2013;27.0% (35.5&#x2013;57.0 mol %)LiO+NaO+KO: 0.5&#x2013;5.0% (0.7&#x2013;20.0 mol %)PbO: 72.0&#x2013;75.0% (39.1&#x2013;45.0 mol %)AsO+SbO: 0.1&#x2013;3.0% (0.1&#x2013;2.0 mol %).

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

The projection type display apparatus according to the present invention has a prism for separating incident light into a plurality of light components and combining the plurality of modulated color components. The prism is constituted by a plurality of prism assemblies, each including an optical member made of an optically transparent material having a photoelastic constant whose absolute value is not greater than &plus;1.5&times;10 cm /N with respect to the incident light. More preferably, these plurality of prism assemblies are arranged such that each of a plurality of the separated color components is totally reflected by any of the prism assemblies.

Projection type display apparatus

A mirror comprises a transparent glass substrate and a dielectric multilayer film laminated on one surface (entrance surface) of the glass substrate. The dielectric multilayer film is formed by layers made of a high refractive index material and layers made of a low refractive index material which are alternately laminated, and is applied to a projection type display apparatus. The material and thickness of each layer are set so as to yield a polarization characteristic for causing reflected light to approach linearly polarized light.

Mirror and 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

By providing a normally deposited layer as a buffer layer between a substrate and an obliquely deposited layer, it is possible to prevent contaminants on the substrate from diffusing into the obliquely deposited layer. Also, by providing a normally deposited layer as a passivation layer on the uppermost obliquely deposited layer, absorption of water vapor in the air by the obliquely deposited layer is prevented. Further, by forming a laminated object comprising obliquely deposited layers and dense normally deposited layers, strength of each obliquely deposited layer itself is increased and relaxation of its columnar structure can be suppressed with certainty because both the diffusion of contaminants from the substrate and the absorption of water in the air is prevented. Thus, by removing factors to accelerate the relaxation of columnar structure in the obliquely deposited layer, clouding of the obliquely deposited film layer can be prevented.

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Yokohama, Japan

Mikio Okamoto