Hoya Corporation

Yoshiko Kasuga

Xuelu Zou

Yasuhiro Fujiwara

Kazuo Tachiwana

Hiroaki Yanagita

Mikio Ikenishi

A method of making a press-moldable glass, including melting starting materials, forming a melt, and annealing a formed glass, wherein the melt has a composition such that, (1) when rapidly cooled to room temperature, it becomes glass that has a scattering coefficient of less than 0.005 cmat wavelengths of from 400 to 2,500 nm or comprises crystals with a volumetric ratio of less than 10, and (2) when maintained for three hours at a temperature 10&#xb0; C. higher than the glass transition temperature, maintained for 10 min at a temperature yielding a viscosity of 10to 10dPa&#xb7;s, and then rapidly cooled to room temperature, (3) the resulting glass has (a) a scattering coefficient of at least one wavelength from 400 to 2,500 nm of greater than 0.01 cmor (b) crystals with a volumetric ratio of greater than 10. A temperature for annealing is lower than for glass transition.

Optical glass, glass material for press molding, optical element, and method of manufacturing same

Preforms for precision press molding made of optical glass, optical elements, and methods of manufacturing the same are provided. The preforms are suited to precision press molding having a broad range of dispersion characteristics, a low glass transition temperature, a low sag point, and good resistance to devitrification while containing no PbO. The optical element is obtained by precision press molding the preform. One example of the preform has a refractive index (nd) of greater than or equal to 1.7 and an Abb&#xe9; number (vd) of less than or equal to 32. The other example of the preform has an Abb&#xe9; number (vd) exceeding 32.

Preforms for precision press molding, optical elements, and methods of manufacturing the same

An optical glass having high refractivity and a low sag temperature and having a low-temperature softening property that enables precision press-molding is provided, and the optical glass contains, by mol %, 5 to 50% of BO, 3 to 50% of SiO, 5 to 40% of TiO, 1 to 40% of ZnO, 5 to 20% of LaO, 0 to 10% of GdO, 0 to 15% of NbO, 0 to 10% of ZrO, 0 to 5% of TaO, 0 to 10% of BiO, 0 to 10% of MgO, 0 to 8% of CaO, 0 to 10% of SrO, 0 to 10% of BaO, provided that the total content of MgO, CaO, SrO and BaO is 15% or less, 0 to 20% of LiO, and 0 to 5% of NaO, optionally containing SbOas a refining agent, and having a refractive index (nd) of 1.8 or more and an Abbe's number (&#x3bd;d) of 35 or less.

Optical glass, precision press-molding preform, process for producing the preform, optical element and process for producing the element

The present invention relates to an optical glass having a refractive index (nd) of greater than or equal to 1.65 and an Abb&#xe9; number (&#x3bd; (nu)d) of greater than or equal to 50 for use in precision press molding. The glass exhibits that a ratio &#x3b1; (alpha)1/&#x3b1; (alpha)2 is less than 17 when temperature denoting maximum value of differential in amount of elongation of glass relative to temperature differential DELTAT (where DELTAT denotes a constant value of 1&#xb0; C. or less) over a temperature range from glass transition temperature (Tg) to sag temperature (Ts) is denoted as T1, average coefficient of linear expansion over a range from T1&#x2212;5&#xb0; C. to T1+5&#xb0; C. is denoted as alpha1, and average coefficient of linear expansion over a range from the glass transition temperature (Tg)&#x2212;160&#xb0; C. to the glass transition temperature (Tg)&#x2212;140&#xb0; C. is denoted as alpha2.

Optical glass, preform for precision press molding and method of manufacturing thereof, optical element and method of manufacturing thereof

An optical glass which has an Abbe's number (&#x3bd;d) of 50 to 59, has the property of not easily reacting with a press mold, a low-temperature softening property, excellent glass stability and high refractivity, and is suitable for precision press-molding. The optical glass comprising BOand SiOas essential components and having a BOand SiOtotal content (BO+SiO) of 45 to 70 by mol % and an SiOcontent/BOcontent molar ratio (SiO/BO) of from 0.1 to 0.5, the optical glass further comprising, by mol %, 5 to 15% of LaO, 0.1 to 8% of GdO, provided that the total content of LaOand GdOis 8% or more, 0 to 10% of YO, 3 to 18% of LiO, provided that the molar ratio of the content of LiO to the total content of BOand SiO[LiO/(BO+SiO)] is over 0 but not more than 0.2, 0.1 to 15% of ZnO, 2 to 20% of CaO, 0 to 5% of BaO, provided that the content of BaO is smaller than the content of ZnO, 0 to 5% of SrO, 0 to 5% of MgO, provided that the molar ratio of the total content of MgO, CaO, SrO and BaO to the total content of BOand SiO[(MgO+CaO+SrO+BaO)/(BO+SiO) is from 0.1 to 0.4, and 0 to 5% of ZrO, and having a refractive index (nd) and an Abbe's number (&#x3bd;d) which satisfy the equation (1),&#x3bd;d&#x2267;308.5&#x2212;150&#xd7;nd (in which 50&#x2266;&#x3bd;d&#x2266;59)&#x2003;&#x2003;(1).

Optical glass, preform for precision press-molding, process for the production of the preform, optical element, and process for the production of the element

The optical glass has a refractive index of equal to or greater than 1.65 and an Abb&#xe9; number ranging from 50 to 60. In the optical glass, as molar basis, a ratio of SiOcontent to BOcontent is greater than 0.5 and equal to or less than 0.90; a total content of SiOand BOranges from 50 to 70 percent; LiO content ranges from 5 to 20 percent; LaOcontent ranges from 0.5 to 22 percent; a ratio of ZnO content to RO (MgO, CaO, SrO and BaO) is equal to or greater than 0.5; a total content of GdO, YOand YbOranges from 1 to 15 percent; SbOcontent ranges from 0 to 1 percent; and no BaO is comprised, or a ratio of the total content of LaO, GdO, YOand YbOto the content of BaO is equal to or greater than 10.

Optical glass, precision press molding preform and optical element

An optical glass taking account of meltability and the moldability of a preform, having optical constants including a refractive index (nd) of at least 1.57 but less than 1.67 and an Abbe's number (&#x3bd;d) of over 55 but not more than 65, having the property of softening at a low temperature and being suitable as a glass for precision press-molding, the optical glass including an optical glass containing BO, SiO, LaO, GdO, an alkali metal oxide and an alkaline earth metal oxide as essential components, having a BOand SiOtotal content of 52% by weight or more and having an SiO/BOcontent ratio of from 0.38 to 1.2, and an optical glass wherein the relationship of the refractive index (nd) and the Abbe's number (&#x3bd;d) satisfies the equation (1),&#x3bd;&#x3e;260&#x2212;126&#xd7;. &#x2003;&#x2003;(1)

Optical glass, precision press-molding preform, process for production thereof, optical element and process for the production thereof

Provided are optical glass exhibiting a refractive index (nd) in a range of 1.75 to 1.87, an Abb&#xe9; number (&#x3bd;d) in a range of 80 to 45, and excellent low-temperature softening properties even when not incorporating ThOas well as permitting a low production cost; a precision press molding preform and an optical element comprised of such glass; a method of manufacturing the preform; and a method of manufacturing the optical element. The optical glass comprises, in a molar percent, 30 to 45 percent of BO, 2 to 15 percent of SiO, 10 to 20 percent of LaO, 1 to 10 percent of TiO, 10 to 30 percent of ZnO, 2 to 15 percent of LiO, higher than 0 percent and 10 percent or less of WO, 0 to 15 percent of NbO, and 0 to 10 percent of ZrO, wherein the total amount of the above-mentioned components is higher than 95 percent, the glass exhibits a refractive index (nd) in a range of 1.75 to 1.87, and an Abb&#xe9; number (&#x3bd;d) in a range of 80 to 45. The precision press molding preform and the optical element are comprised of the glass. In the method of manufacturing a precision press molding preform, the preform comprised of the optical glass is formed. The method of manufacturing an optical element employs the precision press molding preform.

Optical glass, precision press molding preform and method of manufacturing the same, optical element and method of manufacturing the same

An optical glass being free of lead and fluorine, having a low glass transition temperature permitting press-molding with a mold formed of stainless steel and having high climate resistance includes an optical glass comprising, by mol %, 25 to 44% of PO, 10 to 40% of a total of LiO, NaO and KO, 5 to 40% of ZnO, 1 to 35% of BaO and at least one components selected from NbO, BiOand WO, having a glass transition temperature (Tg) of 370&#xb0; C. or lower and being free of lead and fluorine and an optical glass which is free of lead and fluorine, has a mass loss ratio of less than 0.25% when immersed in pure water, and has a glass transition temperature (Tg) of 370&#xb0; C. or lower.

Optical glass, preform for press molding and optical element

An optical glass having a refractive index (nd) of 1.57 to 1.67, an Abbe's number (&#x3bd;d) of 55 to 65 and a glass transition temperature (Tg) of 560&#xb0; C. or lower and having a low-temperature softening property and excellent climate resistance or a haze value of 3% or less, or an optical glass comprising, by mol %, 22 to 40% of BO, 12 to 40% of SiO, 2 to 20% of LiO, 5 to 15% of CaO, 2 to 14% of ZnO, 0.5 to 4% of LaO, 0 to 3% of GdO, 0 to 3% of YO, the total content of LaO, GdOand YObeing at least 1%, 0 to 5% of AlO, 0 to 3% of ZrOand 0 to 5% of BaO, the total content of the above components being more than 96%, and having a refractive index (nd) of 1.57 to 1.67 and an Abbe's number (&#x3bd;d) of 55 to 65.

Optical glass, press-molding preform and optical element

Disclosed is an optical glass comprising, expressed as weight percentages, greater than or equal to 18 percent and less than 30 percent of SiO, greater than or equal to 12 percent and less than 23 percent of BaO, 22 to 37 percent TiO, greater than or equal to 7 percent and less than 16 percent NbO, 5 to 20 percent of NaO, 0 to 6 percent of KO, 0 to 5 percent of CaO, 0 to 5 percent of SrO, 0 to 4 percent of ZrO, 0 to 3 percent of TaO, 0 to 1 percent of SbO, and greater than or equal to 0 percent and less than 0.5 percent of PO, and by essentially not comprising PbO, AsO, and F. The optical glass exhibits a refractive index (nd) greater than or equal to 1.80 and an Abb&#xe9; number (vd) less than or equal to 30. A method of manufacturing a glass material for press molding is disclosed. This method comprises the steps of melting the glass starting materials, forming the glass melt obtained, and annealing the formed glass and is characterized in that: the glass melt has a composition such that, (1) when rapidly cooled to room temperature, said glass melt becomes glass that has a scattering coefficient of less than 0.005 cmat wavelengths of from 400 to 2,500 nm or comprises crystals with a volumetric ratio of less than 10, and (2) when maintained for three hours at a temperature 10&#xb0; C. higher than the glass transition temperature, maintained for 10 min at a temperature yielding a viscosity of 10to 10dPa&#xb7;s, and then rapidly cooled to room temperature, said glass melt becomes glass that has a scattering coefficient at at least one wavelength from 400 to 2,500 nm of greater than 0.01 cmor comprises crystals with a volumetric ratio of greater than 10; and an annealing of said formed glass is conducted at a temperature lower than the glass transition temperature.

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Koganei, Japan

Yoshiko Kasuga