JP3219941B2 - Optical glass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical glass, and more particularly, to an optical glass which is not only excellent in precision press moldability but also used in combination with a material such as silicon which generally has a smaller thermal expansion coefficient than glass. The present invention relates to an optical glass suitable for manufacturing a glass molded product.

[0002]

2. Description of the Related Art In recent years, a method for manufacturing a glass block, a glass lens, and the like by processing glass into a desired shape by precision press of glass requires grinding or polishing after press molding. It has been developed because it has such advantages as not having. In this method, since the glass to be molded and the mold generally need to be heated to a temperature close to or above the deformation point of the glass during press molding, the value of the deformation point of the glass to be molded is difficult to perform precision press molding of glass. Is an important factor in determining
That is, as the yield point of the glass becomes higher, the mold during press molding is exposed to a higher temperature, so that the mold is rapidly deteriorated by oxidation or the like, and the life of the mold is shortened. Therefore, in the production of a glass block and a glass lens by press molding of glass, it is advantageous that the glass to be molded has a low yield point and is easily softened in order to prevent deterioration due to oxidation of the press die.

[0003] From such a viewpoint, many precision press-molding glasses having a low melting point are commercially available, and a typical example thereof is a glass containing a large amount of an alkali oxide which is a low melting point-imparting component. However, glass containing a large amount of this alkali oxide has a low melting point suitable for precision press molding, but has a thermal expansion coefficient of, for example, 90 × 10
^-7 / ° C., and the obtained glass molded product is converted to a low-expansion material such as silicon (thermal expansion coefficient α = 32 × 10 ⁻⁷ /
When used in combination with (.degree. C.), the glass molded article has a significantly larger coefficient of thermal expansion than that of silicon.

On the other hand, focusing only on the low coefficient of thermal expansion, the SK of the SiO ₂ —B ₂ O ₃ —BaO based optical glass
No. 5 has a coefficient of thermal expansion of 66 × 10 ⁻⁷ / ° C., and Pyrex (code No. # 7740) of SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —R ₂ O based glass has a thermal expansion coefficient of Although the coefficient is 34 × 10 ⁻⁷ / ° C., which is closer to the coefficient of thermal expansion of silicon than the above-mentioned alkali metal oxide-containing glass, these low coefficient of thermal expansion glasses have a yield point of 6%.
50 ° C (SK5), 620 ° C (Pyrex)
Due to its high melting point, it cannot be used for precision press molding.

When the optical glass is press-molded as described above and the obtained glass molded product is used in combination with a low-expansion material such as silicon, the optical glass itself has a low melting point and a low thermal expansion coefficient. Is required, but no glass meeting these two requirements has been found so far. Also, this kind of glass was obtained
Contact between glass molded products or between glass molded products and other materials
The attachment and bonding can be performed using UV-curable resin.
Has good transmission characteristics in the ultraviolet,
Things are desired.

Accordingly, an object of the present invention is to provide a molded product obtained by press molding with a low-expansion material such as silicon because it has a low yield point and a low melting point, and is suitable for precision press molding and has a small coefficient of thermal expansion. suitable der to combination use
Another object of the present invention is to provide an optical glass which has excellent transmittance characteristics in the ultraviolet region and has less coloring .

[0007]

In order to achieve the above-mentioned object, the present inventor has proposed a method of producing a SiO ₂ -B ₂ which can be operated stably.
As a result of searching for an additive component effective for lowering the yield point (melting point) and lowering the coefficient of thermal expansion of the glass in which O ₃ is a glass skeleton forming component, ZnO did not increase the coefficient of thermal expansion of the glass. It has been found that the yield point (melting point) is lowered.

In order to lower the yield point of the glass to a level sufficient for use in precision press molding, a large amount of ZnO, which could not be considered so far, is contained, and the skeleton-forming components SiO ₂ and B ₂ O ₃ are contained. by limiting the amount of interest, low yield point, and thermal expansion coefficient rather small, also
We succeeded in obtaining stable glass with no problems such as coloring .

Accordingly the present invention as a glass component, the _{SiO 2 1~30wt%, B 2 O} 3 and 15 to 40 wt%, (not included, however 40 wt%) of ZnO 40~60wt%, 0~15wt% of MgO 0 to 10 wt% of CaO, 0 to 10 wt% of SrO, 0 to 10 wt% of BaO, 0 to 20 wt% of PbO [However, the total amount of ZnO, MgO, CaO, SrO, BaO and PbO is 40 to 60 wt% (Excluding 40 wt%)], a glass containing 0 to 10 wt% (but not including 0 wt%) of Al ₂ O ₃ , wherein the total amount of the glass components is 75
Der wt% or more is, further 0-10 wt% of GeO _2, [provided that the total amount is 3 to 30 wt% of SiO ₂ and GeO _2], La ₂ O ₃ and 0 to 20 wt%, a Y ₂ O ₃ 0 10 to 10 wt%, Gd ₂ O ₃ is 0 to 10 wt%, provided that the total amount of La ₂ O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ is 0 to 2
0 wt%], Nb ₂ O ₅ is less than 0 to 9 wt% , Ta ₂ O ₅ is less than 0 to 9 wt% , [however , the total amount of Nb ₂ O ₅ and Ta ₂ O ₅ is less than 0 to 9 wt%], ZrO ₂ the 0-5 wt%, is summarized as optical glass characterized that you containing TiO ₂ 0 to 3wt%.

[0010] The present invention is a glass component, the _{SiO 2 1~30wt%, B 2 O} 3 and 15 to 40 wt%, (not included, however 40 wt%) of ZnO 40~60wt%, 0~15wt% of MgO 0 to 10% by weight of CaO, 0 to 10% by weight of SrO, 0 to 10% by weight of BaO, 0 to 20% by weight of PbO [However, ZnO, MgO, CaO, SrO, BaO and
The total amount of PbO is 40 to 60% by weight (excluding 40% by weight)
A ) containing 0 to 10 wt% (but not including 0 wt% ) of Al ₂ O ₃ , wherein the total amount of the glass components is 75%
wt% or more, yield point of 560 ° C or less and 70 × 10 ^-7
With a coefficient of thermal expansion of less than / ° C and transmission at a thickness of 2 mm
80% wavelength at 288-350nm
The gist is an optical glass. Hereinafter, the present invention will be described in detail.

First, the reasons for limiting each component in the optical glass of the present invention will be described.

SiO ₂ is a basic component for forming a glass skeleton and is a component essential for stable operation and glass formation. For this reason, it is necessary to contain at least 1 wt% of SiO _2, but if it exceeds 30 wt%, the glass is liable to phase separation. Therefore, the content of SiO ₂ is 1 to 30 wt%
Is limited to A particularly preferred content of SiO ₂ is 3 to 3
0 wt%.

Further, for the purpose of improving coloring and the like, SiO ₂
Can be replaced with GeO ₂ , but GeO _2
If the amount of ₂ exceeds 10%, the durability deteriorates.
The amount of O ₂ is limited to 0-10 wt%. In order to maintain glass devitrification resistance and prevent phase separation, SiO ₂ and GeO are used.
_The total amount with ₂ must be in the range of 3 to 30% by weight.

[0014] B ₂ O ₃ is also a basic component for forming the skeleton of glass, it is an essential component in the stable operation and the glass formation. B ₂ O ₃ is 15 because it is effective in lowering the liquidus temperature.
It is necessary to contain it in an amount of not less than wt%, but if it exceeds 40 wt%, the devitrification resistance and the chemical durability are significantly reduced.
The content of B ₂ O ₃ is limited to 15 to 40 wt%. A particularly preferred B ₂ O ₃ content is 20 to 40% by weight.

[0015] ZnO is an essential component for obtaining desired properties, that is, a low yield point and a low coefficient of thermal expansion. To lower the yield point without increasing the coefficient of thermal expansion, use ZnO
Requires more than 40% by weight, but if it exceeds 60% by weight, vitrification becomes difficult. Preferably it is more than 40 wt% and 55 wt% or less. However, for the purpose of adjusting the thermal expansion coefficient, part of ZnO, 15 wt% of MgO,
aO is 10 wt%, SrO is 10 wt%, BaO is 10 wt%
Can be replaced with these alkaline earth oxides, respectively, with the upper limit of each. However, if it exceeds the above range, the thermal expansion coefficient becomes too large, so that MgO is 0 to 15%.
wt%, CaO is 0-10 wt%, SrO is 0-10 wt%,
BaO is limited to 0 to 10 wt%. Also, the refractive index nd
Can be replaced with PbO for the purpose of increasing PbO. However, if the amount exceeds 20% by weight, coloring becomes strong. Therefore, the amount of PbO is 0
It is limited to ~ 20 wt%.

In order to maintain the properties of glass as described above, divalent metal oxides such as ZnO, MgO, Ca
The total amount of O, SrO, BaO and PbO is limited to more than 40% by weight and not more than 60% by weight, and more than 40% by weight and 55% by weight.
It is preferred that:

Al ₂ O ₃ is a component that has the effect of improving the durability of the glass and preventing phase separation, and is an essential component. However, if it exceeds 10 wt%, the devitrification resistance of the glass deteriorates. , Al ₂ O ₃ is limited to more than 0 wt% and not more than 10 wt%, preferably 0.5 to 10 wt%.

Li ₂ O has the effect of lowering the melting point of glass and preventing phase separation. Although effective with a small amount of addition,
If a large amount is added, the yield point is lowered and at the same time the coefficient of thermal expansion is significantly increased. Therefore, in order to maintain the desired coefficient of thermal expansion, it must not exceed 7 wt%. Thus the amount of Li ₂ O is limited to 0~7wt%.

For the purpose of adjusting the optical constant and improving the durability, La ₂ O ₃ which has the effect of increasing the refractive index nd can be added. However, if it exceeds 20 wt%, the devitrification resistance decreases significantly, the amount of La ₂ O ₃ is 0~20wt
%. Further, a part of La ₂ O ₃ can be replaced with a limit of 10 wt% of Y ₂ O ₃ and a limit of 10 wt% of Gd ₂ O ₃ . However, if it exceeds 10% by weight, the devitrification resistance decreases, so that the amounts of Y ₂ O ₃ and Gd ₂ O ₃ are 0
Limited to 10 wt%, La ₂ O ₃ , Y ₂ O ₃ and Gd ₂
The total amount with O ₃ must also be in the range of 0 to 20% by weight.

In order to improve durability, Nb ₂ O ₅ , T
a ₂ O ₅ to be added in a range of less than 0 to 9 wt%, respectively.
However, the total amount of Nb ₂ O ₅ and Ta ₂ O ₅ is 9 wt% or more.
Then , the coloring becomes strong, and the glass becomes yellowish. Therefore, also the total amount of Nb ₂ O _5, Ta ₂ O ₅ is limited to less than 0 to 9 wt%.

For the purpose of improving durability, ZrO ₂ , Ti
O ₂ or the like can be added. However, if the amount of ZrO ₂ exceeds 5 wt%, unmelted matter is liable to be formed during melting and melting becomes difficult, so the amount of ZrO ₂ is 0 to 5 wt%.
Is limited to Further, since TiO ₂ is reduced at the same time the devitrification resistance when the coloring and exceeds 3 wt% stronger, TiO ₂
Is limited to 0-3 wt%.

For the purpose of improving defoaming and coloring, As ₂ O ₃ , Sb ₂ O ₃ , SnO, SnO ₂
One or more of them can be added. But A
4 w in total with s ₂ O ₃ , Sb ₂ O ₃ , SnO and SnO ₂
Even if it is added in excess of t%, the effect of improving defoaming and coloring is not improved, so it is desirable to use them in the total amount of 0 to 4 wt%.

In the glass of the present invention, in addition to the above-mentioned components, F and Bi may be used as long as the properties of the glass are not deteriorated.
_{2 O 3, Yb 2 O 3} , WO 3 or the like as appropriate to a trace amount of Na ₂
O and K ₂ O can be added.

The optical glass of the present invention has a deformation point of, for example, 560 ° C. or less and a thermal expansion coefficient of 70 × 10 ⁻⁷ / ° C. or less, so that precision press molding is possible. No distortion or breakage occurs when used in combination with low expansion materials such as silicon.

Further, the optical glass of the present invention has good transmittance characteristics in the ultraviolet region and has little coloring, so that the resulting molded articles or the ultraviolet ray-curable resin can be used for bonding and joining between molded articles and other materials. And the like can also be used.

[0026]

The present invention will be further described with reference to the following examples. Example 1 As raw materials, SiO ₂ , H ₃ BO ₃ , ZnO, Al (O
H) ₃ , Li ₂ CO ₃ , after blending a glass batch using As ₂ O ₃ as a defoaming agent, melting at 1100 ° C. using a platinum crucible, homogenizing by stirring, and then removing bubbles by fining, Glass was produced by pouring into a mold and slowly cooling. A glass block having a predetermined weight was cut out from the produced glass, heated to a temperature of 500 ° C. slightly higher than the glass transition point of 475 ° C., and kept at that temperature for 3 hours.
The strain inside the glass was removed by cooling from a holding temperature to a temperature lower by 200 ° C. at a constant temperature of −30 ° C./hr. The strain-reduced glass was processed into a cylindrical shape having a diameter of 5 mm and a length of 20 mm, and the glass transition point (° C.), the yield point (° C.),
Coefficient of thermal expansion from 0 ° C. to 300 ° C. (× 10 ⁻⁷ / cm
/ Cm / ° C). Further, both sides of the strain-reduced glass block are polished with a thickness of 2 mm, and the wavelength is 250 to 700.
Measure the spectral transmittance (including reflection loss) in nm,
From the obtained spectral transmittance curve, a wavelength indicating a transmittance of 80% was obtained, and the degree of coloring was evaluated.

Table 1 shows the measurement results of the glass transition point, the yield point, the coefficient of thermal expansion, and the degree of coloring of the optical glass obtained in this example.

According to Table 1, the optical glass of Example 1 has a deformation point of 505 ° C., a low softening temperature, and a thermal expansion coefficient of 64 × 1.
It was 0 ^-7 cm / cm / ° C and had low expansion property. Further, the wavelength at a transmittance of 80% at a thickness of 2 mm is 290 nm, which has good transmittance characteristics in the ultraviolet region, has little coloring, and it is clear that an ultraviolet curable resin or the like can be used for adhesion, bonding, and the like. It became.

Further, after a spherical preform was obtained by cold polishing a part of the produced glass, a rectangular parallelepiped glass block was produced by precision press molding.
It was confirmed that it was suitable for precision press. When a glass block obtained by precision press molding was incorporated into a silicon block, no distortion or breakage was observed.

Examples 2 to 17 Glasses were produced in the same manner as in Example 1 except that the glass compositions shown in Tables 1 and 3 were used. The coefficient of thermal expansion and the degree of coloring were measured. As shown in Tables 1 to 3, the measurement results are shown in Examples 2-1.
Glass No. 7 has a yield point of 495-555 ° C., a low softening temperature, and a thermal expansion coefficient of 50-70 × 10 ⁻⁷ cm / c.
m / ° C. and low expansion. Further, the wavelength at a transmittance of 80% at a thickness of 2 mm was 288 to 350 nm, and it was confirmed that the film had good transmittance in the ultraviolet and had little coloring.

A spherical preform was obtained from the glasses of Examples 2 to 17 by cold polishing in the same manner as in Example 1, and then a rectangular parallelepiped glass block was produced by precision press molding. It was confirmed that it was suitable for pressing. When a glass block obtained by precision press molding was incorporated into a silicon block, no distortion or breakage was observed.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

As described above, according to the present invention, since the yield point is low and the melting point is low, it is suitable for precision press molding and has a low coefficient of thermal expansion. An optical glass suitable for use in combination with the low expansion material is provided.

Claims (4)

(57) [Claims] As claimed in claim 1] glass component, the _{SiO 2 1~30wt%, B 2 O} 3 and 15 to 40 wt%, (not included, however 40 wt%) of ZnO 40~60wt%, 0~15wt% of MgO, CaO 0-10 wt%, SrO: 0-10 wt%, BaO: 0-10 wt%, PbO: 0-20 wt%, provided that the total amount of ZnO, MgO, CaO, SrO, BaO and PbO is 40-60 wt% (however, 40 wt% is not included), the Al ₂ O ₃ 0~10wt% (except 0 wt% is not included) a glass containing, total amount of the glass component 75
Der wt% or more is, further 0-10 wt% of GeO _2, [provided that the total amount is 3 to 30 wt% of SiO ₂ and GeO _2], La ₂ O ₃ and 0 to 20 wt%, a Y ₂ O ₃ 0 10 to 10 wt%, Gd ₂ O ₃ is 0 to 10 wt%, provided that the total amount of La ₂ O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ is 0 to 2
0 wt%], Nb ₂ O ₅ is less than 0 to 9 wt% , Ta ₂ O ₅ is less than 0 to 9 wt% , [however , the total amount of Nb ₂ O ₅ and Ta ₂ O ₅ is less than 0 to 9 wt%], ZrO ₂ the 0-5 wt%, the optical glass characterized that you containing TiO ₂ 0 to 3wt%. As wherein the glass component, the _{SiO 2 1~30wt%, B 2 O} 3 and 15 to 40 wt%, (not included, however 40 wt%) of ZnO 40~60wt%, 0~15wt% of MgO, CaO 0-10 wt%, SrO: 0-10 wt%, BaO: 0-10 wt%, PbO: 0-20 wt%, provided that the total amount of ZnO, MgO, CaO, SrO, BaO and PbO is 40-60 wt% (however, 40 wt% is not included), the Al ₂ O ₃ 0~10wt% (except 0 wt% is not included) a glass containing, total amount of the glass component 75
Der wt% or more is, sag and 70 × 10 ^-7 of 560 ° C. or less
With a coefficient of thermal expansion of less than / ° C and transmission at a thickness of 2 mm
Optical glass wavelengths rate 80% and wherein the 288~350nm der Rukoto. 3. A optical glass according to claim 1 or 2, the SiO ₂ 3 to 30 wt%, B ₂ O ₃ and 20 to 40 wt%, the ZnO 40~55wt% (where 40 wt% is not included), 0 to 15% by weight of MgO, 0 to 10% by weight of CaO, 0 to 10% by weight of SrO, 0 to 10% by weight of BaO, 0 to 20% by weight of PbO. amounts (not included however 40wt%) 40~55wt%], the Al ₂ O ₃ containing 0.5-10%, optical glass, characterized in that it further contains 0～7Wt% of Li ₂ O. 4. The optical glass according to any one of claims 1 to 3, wherein the optical glass is an optical glass for precision press.