JP6864731B2 - Optical glass, optical elements using optical glass, optical devices - Google Patents

Description

The present invention relates to, for example, optical glass, optical elements, and optical devices.

In recent years, remarkable progress has been made in miniaturization and weight reduction in the design of optical systems such as cameras. High-performance optical glass is required to achieve those product performances. As such an optical glass, for example, glass _{SiO 2} -PbO-Li 2 O system is disclosed in Patent Document 1.

Japanese Unexamined Patent Publication No. 03-050138

However, since the composition system as described above contains a harmful lead component (PbO), it is environmentally unfavorable, and it is desired that the glass component does not contain a lead component.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical glass having high refraction and low dispersion, which does not substantially contain PbO.

A first aspect of the present invention to solve the aforementioned problem, in mass%, the content of each component, SiO ₂ content: 2 to _10%, B 2 _{O 3} content: 12 to 25%, ZnO content: 2-10%, La ₂ O ₃ content: 20-55%, WO ₃ content: 1-10%, Gd ₂ O ₃ content: 3.4-9%, Na ₂ O and K _{Total 2} O content (Na ₂ O + K ₂ O): 0 to 0.1%, Nb ₂ O ₅ content: 0 to 3% , Y ₂ O ₃ content: 3.8 to 15% . and it does not substantially contain PbO and Li ₂ O, an optical glass is. In terms of mass%, the content of each component is SiO ₂ content: 2 to 10%, B ₂ O ₃ content: 12 to 25%, ZnO content: 2 to 10%, La ₂ O ₃ content. : 20-55%, WO ₃ content: 1-10%, Gd ₂ O ₃ content: 3.4-9%, _{total Na 2} O and K ₂ O content (Na ₂ O + K ₂ O): 0 With optical glass having ~ 0.1%, Nb ₂ O ₅ content: 0 to 3%, BaO content: 0.5 to 1.8%, and substantially free of _{PbO and Li 2 O.} is there. In terms of mass%, the content of each component is SiO ₂ content: 2 to 10%, B ₂ O ₃ content: 12 to 25%, ZnO content: 2 to 10%, La ₂ O ₃ content: 20-55%, WO ₃ content: 1-10%, Gd ₂ O ₃ content: 3.4-9%, _{total Na 2} O and K ₂ O content (Na ₂ O + K ₂ O): 0- It is an optical glass having 0.1%, Nb ₂ O ₅ content: 0 to 3%, Ta ₂ O ₅ content: 0 to 12%, and substantially free of PbO and Li _{2 O.}

A second aspect of the present invention is an optical element comprising the optical glass of the first aspect.

A third aspect of the present invention is an optical device including the optical element of the second aspect. A fourth aspect of the present invention is a lens barrel comprising the optical element of the second aspect.

It is a perspective view of the image pickup apparatus provided with the optical element using the optical glass which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention (hereinafter, referred to as “the present embodiment”) will be described. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified and implemented within the scope of the gist thereof. Unless otherwise specified in the present specification, the content of each component shall be the mass% of the total mass of the glass in the oxide conversion composition. The oxide-equivalent composition described here is the total of the oxides, assuming that all the oxides, composite salts, etc. used as raw materials for the glass constituents of the present invention are decomposed into oxides when melted. It is a composition in which each component contained in a glass is described, with the mass being 100% by mass.

The optical glass according to the present embodiment is an optical glass that does not substantially contain PbO. In addition, in this specification, "substantially not contained" means that the component is not contained as a component affecting the characteristics of the glass composition in excess of the concentration unavoidably contained as an impurity. means. For example, contamination of about 100 ppm or less in the manufacturing process is not substantially contained.

Specific examples of the component composition of the optical glass according to the present embodiment are SiO _{2 2 to} 10%, B ₂ O ₃ 10 to 25%, Zn O 2 to 10%, and La _{2 O 3} 20 to 55% in terms of mass%. , _WO 3 1~10%, contains components _{of, Na 2 O + K 2 O} 0~0.1% as optional _{components, Gd 2 O 3 0~9%,} Nb 2 O 5 0~3%, each of containing components, and include those that do not substantially contain PbO and Li 2 _O.

SiO ₂ has the effect of forming a glass skeleton and improving chemical durability. When _{the content of SiO 2} is less than 2% by mass, the devitrification stability of the glass becomes insufficient. Further, when _{the content of SiO 2} exceeds 10%, it becomes difficult to make the glass have a high refractive index. Therefore, _{the content of SiO 2} is 2 to 10%, preferably 2 to 9%, and more preferably 3 to 9%.

B ₂ O ₃ is a component that forms a glass skeleton. When _{the content of B 2} O ₃ is less than 10%, the devitrification stability of the glass becomes insufficient. Further, when _{the content of B 2} O ₃ exceeds 25%, it becomes difficult to make the glass have a high refractive index. Therefore, _{the content of B 2} O ₃ is 10 to 25%, preferably 10 to 23%, and more preferably 10 to 21%.

ZnO is a component having an effect of increasing the refractive index of glass, but when the content thereof exceeds 10%, the devitrification stability is lowered. Therefore, the ZnO content is 2 to 10%, preferably 2 to 9%, and more preferably 2 to 8%.

La ₂ O ₃ is a component having an effect of increasing the refractive index of glass, but when the content thereof exceeds 55%, the devitrification stability is lowered. Further, when _{the content of La 2} O ₃ is less than 20%, it becomes difficult to obtain a high refractive index. Therefore, _{the content of La 2} O ₃ is 20 to 55%, preferably 25 to 50%, and more preferably 30 to 50%.

WO ₃ is a component that increases the refractive index of glass, but when its content is less than 1%, it becomes difficult to obtain a high refractive index. Further, when _{the content of WO 3} exceeds 10%, the devitrification stability is lowered. Therefore, _{the content of WO 3} is 1 to 10%, preferably 1 to 9%, and more preferably 1 to 8%.

Alkali metal oxides, Na ₂ O and K ₂ O, are components that promote the melting of glass, but their inclusion reduces devitrification stability. From this point of view, the total content of _{Na 2} O and K _{2 O (Na 2} O + K ₂ O) is 0 to 0.1%. When _{the total content of Na 2} O and K ₂ O is more than 0%, _{only one of Na 2} O and K ₂ O may be contained, or both may be contained. It is preferable that Na ₂ O and K ₂ O are not substantially contained. That is, _{the total content of Na 2} O and K ₂ O is preferably 0%. Further, the optical glass according to the present embodiment, even without containing Li 2 _O is an alkali metal oxides are easy to melt the glass, typical temperatures for melting an optical glass (e.g., 1200 to 1400 Can be melted at ° C). Therefore, the optical glass according to the present embodiment does not substantially contain _{Li 2 O.}

Gd ₂ O ₃ is a component having an effect of increasing the refractive index of glass, but when the content thereof exceeds 9%, the devitrification stability is lowered. Therefore, _{the content of Gd 2} O ₃ is 0 to 9%, preferably 0 to 8%, and more preferably 0 to 7%.

Nb ₂ O ₅ is a component that increases the refractive index of glass, but when its content exceeds 3%, the devitrification stability decreases. Therefore, _{the content of Nb 2} O ₅ is 0 to 3%, preferably 0 to 2%, and more preferably 0 to 1%.

The optical glass according to the present embodiment further contains as an optional _{component, BaO, Y 2 O 3,} ZrO 2, TiO 2, Ta 2 O 5, and any one or more selected from the group consisting of _Sb 2 _{O 3} It is preferable to do so. Among them, as a more preferable _{combination, BaO 0~5%, Y 2 O} 3 0~15%, ZrO 2 0~10%, TiO 2 0~10%, Ta 2 O 5 0~20%, Sb 2 O ₃ 0 to 1% more like to contain. Hereinafter, each component will be described.

BaO is a component having an effect of increasing the refractive index of glass, but when the content thereof exceeds 5%, the devitrification stability is lowered. Therefore, the content of BaO is preferably 0 to 5%, more preferably 0 to 4%, and even more preferably 0 to 3%.

Y ₂ O ₃ is a component having an effect of increasing the refractive index of glass, but when the content thereof exceeds 15%, the devitrification stability is lowered. Therefore, _{the content of Y 2} O ₃ is preferably 0 to 15%, more preferably 0 to 13%, and even more preferably 0 to 11%.

ZrO ₂ is a component having an effect of increasing the refractive index of glass and improving chemical durability. When the content exceeds 10%, the devitrification stability is lowered. Therefore, _{the content of ZrO 2} is preferably 0 to 10%, more preferably 1 to 10%, and even more preferably 1 to 9%.

TiO ₂ has the effect of increasing the refractive index of glass and increasing the dispersion. If the content exceeds 10%, it becomes difficult to achieve low dispersion. Therefore, _{the content of TiO 2} is preferably 0 to 10%, more preferably 0 to 9%, and even more preferably 0 to 8%.

Ta ₂ O ₅ has the effect of increasing the refractive index of glass and increasing its density. If the content exceeds 20%, the density of the glass becomes excessively high. Therefore, _{the content of Ta 2} O ₅ is preferably 0 to 20%, more preferably 0 to 18%, and even more preferably 0 to 16%.

Sb ₂ O ₃ functions as a defoaming agent that promotes clarification of glass. Its content is preferably 0 to 1%.

The optical glass according to this embodiment is an environmental pollutant and does not substantially contain harmful PbO (so-called lead-free). Further, it is preferable that the optical glass according to the present embodiment does not substantially contain _{TeO 2 from the viewpoint of not lowering the devitrification stability. Further, although it is possible to contain As 2} O ₃ as a defoaming agent that promotes clarification during the production of optical glass, it is preferable that _{As 2} O ₃ is substantially not contained because it is a harmful substance.

Other components other than the above, such as known fining agents, colorants, defoaming agents, fluorine compounds, and phosphoric acid, for the purpose of clarifying, coloring, decoloring, fine-tuning the optical constant value, etc., as necessary. Can be added in an appropriate amount to the glass composition as long as the effects of the present embodiment can be obtained. Further, not limited to the above components, other components may be added as long as the effects of the present embodiment can be obtained.

The method for producing the optical glass according to the present embodiment is not particularly limited, and a known method can be adopted. Further, as the production conditions, suitable conditions can be appropriately selected. For example, raw materials such as oxides, carbonates, nitrates, and sulfates are mixed so as to have a target composition, melted at preferably 1100 to 1500 ° C., more preferably 1200 to 1400 ° C., and homogenized by stirring. , A manufacturing method or the like in which the foam is cut off and then cast into a mold can be adopted. The optical glass thus obtained can be made into a desired optical element by performing reheat pressing or the like as necessary to process it into a desired shape and polishing or the like.

The optical glass according to the present embodiment preferably has a refractive index (nd) of 1.81 to 1.93, and more preferably 1.83 to 1.91. Further, the optical glass according to the present embodiment preferably has an Abbe number (νd) of 33 to 47, more preferably 34 to 46. Particularly preferable combinations include a refractive index (nd) of 1.81 to 1.93 and an Abbe number (νd) of 33 to 47.

The optical glass according to this embodiment is suitable as an optical element such as a lens provided in an optical device such as a camera or a microscope.

The optical glass according to this embodiment can be used, for example, as an optical element included in an optical device. FIG. 1 shows a perspective view of an image pickup apparatus (optical apparatus) including an optical element using optical glass according to an embodiment of the present invention. The image pickup device 1 is a so-called digital single-lens reflex camera, and the lens barrel 3 is detachably attached to a lens mount (not shown) of the camera body 2. Then, the light passing through the lens 4 of the lens barrel 3 is imaged on the sensor chip (solid-state image sensor) 5 of the multi-chip module 7 arranged on the back side of the camera body 2. The sensor chip 5 is a bare chip such as a so-called CMOS image sensor, and the multi-chip module 7 is, for example, a COG (Chip On Glass) type module in which the sensor chip 5 is bare-chip mounted on a glass substrate 6.

The optical device is not limited to such an image pickup device, and includes a wide range of devices such as a projector and the like. The optical element is not limited to the lens, and examples thereof include a prism and the like.

Next, Examples and Comparative Examples of the present invention will be described. Each table shows the chemical composition of each component of the optical glass according to the examples and the comparative examples based on the mass% based on the oxide, and the evaluation results of the physical properties of the obtained optical glass. The present invention is not limited to these examples.

<Making optical glass>
The optical glass according to each Example and each Comparative Example was produced by the following procedure. First, glass raw materials such as oxides, carbonates, and nitrates were weighed so as to have the chemical composition (mass%) shown in each table. Next, the weighed raw materials were mixed and put into a crucible, melted at a temperature of 1200 to 1400 ° C., and stirred and homogenized. After clarification, each sample was obtained by casting in a mold, slowly cooling, and molding.

<Measurement of optical glass>
The refractive index (nd) and Abbe number (νd) of each sample were measured and calculated using a refractive index measuring device (manufactured by Shimadzu Device Manufacturing Co., Ltd .: KPR-2000). The Abbe number (νd) was calculated based on the following equation (1). The value of the refractive index was set to the fifth decimal place.
νd = (nd-1) / (nF-nC) ... (1)
nd: Refractive index of glass with respect to light with a wavelength of 587.562 nm nF: Refractive index of glass with respect to light with a wavelength of 486.133 nm nC: Refractive index of glass with respect to light with a wavelength of 656.273 nm

From the above, neither the optical glass of the present embodiment, even without containing PbO and Li 2 _O, it was at least confirmed a high refractive index and low dispersion.

1: Imaging device, 2: Camera body, 3: Lens barrel, 4: Lens, 5: Sensor chip, 6: Glass substrate, 7: Multi-chip module

Claims (11)

By mass%, the content of each component,
SiO ₂ content: 2-10%,
B ₂ O ₃ content: 12-25%,
ZnO content: 2-10%,
La ₂ O ₃ content: 20-55%,
WO ₃ content: 1-10%,
Gd ₂ O ₃ content: 3.4-9%,
Total content of Na ₂ O and K _{2 O (Na 2} O + K ₂ O): 0-0.1%,
Nb ₂ O ₅ content: 0-3% ,
Y ₂ O ₃ content: 3.8 to 15%,
, And the and substantially free of PbO and Li ₂ O, the optical glass. By mass%, the content of each component,
BaO content: 0-5% ,
Z rO ₂ content: 0-10%,
TiO ₂ content: 0-10%,
Ta ₂ O ₅ content: 0-20%,
Sb ₂ O ₃ content: 0 to 1%,
The optical glass according to claim 1. By mass%, the content of each component is
SiO ₂ Content rate: 2-10%,
B ₂ O ₃ Content: 12-25%,
ZnO content: 2-10%,
La ₂ O ₃ Content rate: 20-55%,
WO ₃ Content: 1-10%,
Gd ₂ O ₃ Content rate: 3.4-9%,
Na ₂ O and K ₂ Total O content (Na ₂ O + K ₂ O): 0 to 0.1%,
Nb ₂ O ₅ Content rate: 0-3%,
BaO content: 0.5-1.8%,
And PbO and Li ₂ Optical glass that contains substantially no O. By mass%, the content of each component is
Y ₂ O ₃ Content rate: 0 to 15%,
ZrO ₂ Content rate: 0-10%,
TiO ₂ Content rate: 0-10%,
Ta ₂ O ₅ Content rate: 0-20%,
Sb ₂ O ₃ Content rate: 0 to 1%,
The optical glass according to claim 3. By mass%, the content of each component is
SiO ₂ Content rate: 2-10%,
B ₂ O ₃ Content: 12-25%,
ZnO content: 2-10%,
La ₂ O ₃ Content rate: 20-55%,
WO ₃ Content: 1-10%,
Gd ₂ O ₃ Content rate: 3.4-9%,
Na ₂ O and K ₂ Total O content (Na ₂ O + K ₂ O): 0 to 0.1%,
Nb ₂ O ₅ Content rate: 0-3%,
Ta ₂ O ₅ Content rate: 0-12%,
And PbO and Li ₂ Optical glass that contains substantially no O. By mass%, the content of each component is
BaO content: 0-5%,
Y ₂ O ₃ Content rate: 0 to 15%,
ZrO ₂ Content rate: 0-10%,
TiO ₂ Content rate: 0-10%,
Sb ₂ O ₃ Content rate: 0 to 1%,
The optical glass according to claim 5. Refractive index _{(n d)} of Ru der 1.81 to 1.93, the optical glass according to any one of claims 1 to 6. The optical glass according to any one of claims 1 to 7, wherein the Abbe number (νd) is 33 to 47. An optical element comprising the optical glass according to any one of claims 1 to 8. An optical device comprising the optical element according to claim 9. A lens barrel comprising the optical element according to claim 9.

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