TW200800830A - Optical glass for mold press molding - Google Patents

Abstract

Disclosed is a lead-free optical glass for mold press molding which has characteristics required for optical glasses for mold press molding, especially a refractive index (nd) of 1.57-1.62 and an Abbe number (vd) of not less than 55, while being excellent in weather resistance. The lead-free optical glass for mold press molding is characterized by having a composition containing, in mass%, 41-56% of SiO2, 1.5-5% of Al2O3, 7-16% of B2O3, 0.1-10% of CaO, 0-10% of BaO, 0-10% of SrO, 0-5% of ZnO, 1-10% of Li2O, 0-5% of Na2O and 5-15% of La2O3. Preferably, the composition of the optical glass further satisfies the following conditions: MgO + CaO + BaO + SrO is 10-20%, Li2O + Na2O + K2O is 5-12% and 3.2 ≤ SiO2/La2O3 ≤ 15.0.

Description

200800830 IX. Description of the Invention: [Technical Field of the Invention] The present invention relates to an optical glass for press molding. [Prior Art]

In optical lenses such as CDs, MDs, and DVDs, optical lenses such as optical reading lenses, cameras, and general-purpose cameras, the refractive index (nd) is 1.57 to 1.62, and the Abbe number (vd) is used. The optical glass of 55 or more, more specifically, the refractive index (nd) is an Abbé number (vd) of 5 8 5 - 62.0. Previously, as such a glass, a lead-containing glass containing Si〇2_PbO-R'2〇 (R, 2〇 as an alkali metal oxide) as a basic component has been widely used. However, in recent years, it has been gradually replaced in consideration of environmental problems. It is a non-missing glass such as SiCVB2〇3-R〇 (R〇 is a soil-based metal oxide) _R, 2 fluorene (for example, Patent Documents 1 and 2). Patent Document 1: Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. 2004-328068. Solution to Problem The optical reading lens and the photographic lens are shaped as follows. 1 First, the molten glass is dropped from the tip end of the nozzle, and the droplet-shaped glass is temporarily prepared for grinding, polishing, and washing to prepare a preformed glass. Or quench the scales; melt the glass and temporarily make the glass bricks, and also grind the 'grinding and washing' to make the pre-formed glass. Thereafter, the preformed glass in the sub-softened state is press-formed by performing a precision-machined mold, and the surface shape of the mold is detached from the surface of the mold 120054.doc 200800830. Such a method is called a so-called overmolding method and is widely used. "The glass formed by dust drawing is of course required to meet the required constants (refractive index, Abbe number), and the softening point is required to be low to prevent deterioration. The fusion, and the high weather resistance, and the like. Eighth, as previously described, most of the non-lead-based preformed glass does not have the weather resistance of the burr. When the weather resistance of the glass is not sufficient, the glass component is eluted into the polishing washing water or various washing solutions during the cutting, grinding, and washing steps to cause surface deterioration. As a result, it is easy to produce in the forming step, and defects occur in the through-glass, which makes mass production difficult. Moreover, even if it is a final product, there is a problem that the long-term exposure to high temperature and high humidity causes deterioration of the glass surface and impairs reliability. The purpose of the invention is to provide an optical glass for non-missing multi-mode molding, which satisfies the characteristics required for optical glass for die-forming, in particular, the refractive index (nd) is 1.57 to 1.62, and the Abbe number (vd) ) is 55 or more (preferably, the refractive index (nd) is i.575 to 161 g, and the Abbe number state is 585 to 62 and the weatherability is excellent. The technical means for solving the problem. The inventors found that various tests have been carried out. , # is strictly limited

The composition of the Si〇2 B2〇3-R〇_Ri2〇_La2〇3 series glass can achieve the above object and is proposed as the present invention. That is, the optical glass for press molding of the present invention is characterized by containing: 41% to 56% by mass of 〇2, 1> 5 to 5% of 〇12〇3, 120054.doc 200800830 B2〇3 〇·卜 10% CaO, 〇~10%2Ba〇, 〇~1〇%^〇, 〇~5% Zn〇, Bu 10% Li2〇, 〇~5%iNa2〇, 5~i5 % of L a2 0 3 . Advantageous Effects of Invention The optical glass of the present invention has a refractive index (nd) of i.574.62 used in an optical lens such as an optical reading lens of various optical disk systems such as CD, MD, or DVD, a camera, and a photographic lens of a general camera. Abbe number (vd) above 55. Further, since the softening point is low and the glass component is hard to volatilize, the molding precision is not lowered and the mold is poor or contaminated. Further, the working temperature range is wide, the mass production of the preformed glass is excellent, and the weather resistance is good, so that the physical properties are not deteriorated or the surface is deteriorated during the manufacturing step or product use. Therefore, it is suitable as an optical glass for press molding. [Embodiment] The optical glass for press molding of the present invention contains 4 Å to 4 Å, 2 1 5 to 5% of 8 12 〇 3, 7 to 16% of b 2 〇 3, 〇 1 ~1〇% of CaO, 〇~10% of Ba〇, 〇~1〇% of 〇, 〇~5% of 〇, ((7)% of U2〇, 〇~5% of Na2〇, 5~15 The basic composition of the glass of %iLa2〇3. In general, in the non-lead-based glass, a large amount of the alkaline earth metal oxide R0 is contained in order to obtain a high refractive index, which is a cause of lowering the weather resistance of the glass. Therefore, the glass of the present invention contains the component LkO3 which improves the refractive index and the component 提高"3 which improves the weather resistance, suppresses the content of r〇, and contains the essential component CaO as R0, whereby the refractive index can be maintained and the glass can be improved. Weather resistance. X, if it contains La2〇3, there is a tendency to decrease the Abbe number: but it contains B2〇3 to prevent the Abbe number from decreasing. By virtue of this, 120054.doc 200800830 can be obtained with excellent weather resistance, refractive index (nd) of 1.57~1.62, Abbe number (vd) of 55 or more, especially refractive index of 1.575~1.610 (n (j), an optical glass for compression molding of a V (j) having an Abbe number of 58. 5 to 6 2.0, which can be used as an optical lens for optical elements having less dispersion and high function and small size. Further, the present invention The optical glass for press molding preferably has a glass softening point of 65 Å or less (preferably 640 ° C or less, more preferably 630 ° C or less). If the softening point of the glass is lowered, the temperature is low. The lower press molding can suppress the contamination of the mold caused by the oxidation of the mold or the volatilization of the glass component or the fusion of the glass and the mold. The reason for limiting the range of each component as described above is explained. Improve the effect of weather resistance. ^ Summer is 41~56%, preferably 42~53%, t plus better ^4 ancient 3~50·5%. Furthermore, there is increased material casting low or softening Point to the tendency of ^. In addition, the tendency to devitrification is strengthened. On the other hand, if Si02' >, then acid resistance or resistance Weather resistance such as water is deteriorated. B2〇3 is a skeleton component of glass-breaking glass, which has improved resistance to devitrification, and includes: a few: a component that lowers the softening point. Further, there is a glass and a mold which reduce the effect of glass formation. The effect of fusion is 3~16%, preferably 9~16% 10~155%, 仓工+ a, 炸 疋/ and then preferably 12~15% β, When the glass is melted, the volatile matter formed by R 3 . 3- 佤 隹 隹 & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & If there are fewer 〇3, there is a possibility of resistance to devitrification in the right degree range. x, easy to fish mold and = ensure sufficient work temperature is easy, and the cookware is fused. Further, SiO 2 is less 120054.doc 200800830 In the case where V* "D 4· is less than 2〇3, it is difficult to maintain the Abbe number at 55 or more.

The Al2〇3 series and si〇2 together form a component of the glass skeleton and have the effect of improving weather resistance.士,甘θθ,疋 in Si〇2-B2〇3-R〇-R'2〇-La2〇3 series glass, the effect of suppressing the selective elution of alkaline components into the water is significant. It is from 1. 5 to 5%, preferably from 2 to 4.5%, and more preferably from 2·7 4·5/〇. Furthermore, if Α12〇3 is more, it is easy to devitrify. Further, there is a possibility that the melt melting property is deteriorated, and streaks or bubbles remain in the glass, so that the required quality as the peripheral glass of the lens cannot be satisfied. On the other hand, if 丨2〇3 is more than ^, the water resistance and the acid resistance are lowered, and it is difficult to obtain a glass having a very high weather resistance.

An alkaline earth metal oxide (R〇) such as Ca〇, BaO or StO acts as a flux and has an effect of increasing the refractive index without lowering the Abbe number in the glass. Ca 〇, Ba 〇, and Sr 〇 , ' 冲 里 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Further, when R〇 is increased, the preformed glass is melted, the devitrified substance is easily precipitated in the molding step, the liquidus temperature is increased, and the working range is narrowed, which tends to be difficult to produce. Further, the elution from the glass to the polishing washing water or the various washing solutions is increased, the deterioration of the glass surface in the warm and humid state is remarkable, and the weather resistance is likely to be deteriorated. On the other hand, if the RO is decreased, it is liable to cause a decrease in the refractive index or a high softening point.

The Ca lanthanide does not lower the Abbe number and increases the refractive index component. In the high-temperature and wet state, the effect of preventing precipitation on the surface of alkaline or alkaline earth is prevented, and it is an essential component for improving weather resistance. The content of CaO is better 120054.doc 200800830 is 0 · 1~10%, and the cup is dip η Λ , 疋 .5 5%, and then preferably 1-4%. Further, if the Ca0 is increased, the liquidus temperature rises and the devitrification is likely to occur.

Ba〇 is a component that increases the refractive index, and in the glass system, the liquidus temperature is lowered to improve the workability. H In the high-temperature and high-humidity state, the amount deposited from the glass surface is compared with other R〇 components. Significantly more, so f contains a large amount, which may damage the weather resistance of the final product. The content of eBa〇 is preferably G~1G%, especially good and better.

It is 4 to 9% 四 (4) is the composition of the two refractive indices. And compared with _, the amount of precipitation from the glass surface is less under high temperature and humidity. Therefore, by actively using S^, a product excellent in weather resistance can be obtained. The content is preferably from 0.5 to 9% and further preferably from 3 to 8%. Further, when (10) is increased, the liquidus temperature rises and the working range tends to be narrow. Further, in addition to Ca〇, Ba0, or Sr, in order to increase the refractive index, it is also possible to add: MgO. When Mg is added, the content is preferably 5% to 5%, particularly preferably 0 to 3%. When Mg〇 increases, it is easily devitrified.

ZnO has an effect of increasing the refractive index and improving weather resistance. Moreover, the tendency to devitrification is not strong, so even if it is contained in a large amount, it is possible to obtain a glass of uniformity. Its content is 0~5. /. Preferably, it is 5 to 4%, and more preferably it is 3%. If ΖηΟ increases, there is a tendency for the Abbe number to decrease.

An alkali metal oxide (R, 2?) such as LhO or NkO is used to lower the softening point component. The total amount of LiW and NkO is preferably 5 to 12%, and 6 to 11% is particularly preferably '7 to (four). Furthermore, when R is increased by 2, the liquidus temperature is likely to rise and the operating temperature range is narrowed. At this time, it is possible to cause damage to mass production. 120054.doc -10-

200800830 The impact and the tendency to weather resistance deteriorate. Conversely, if R, 2 〇 decreases, the softening point increases. Among R'2〇, the effect of lowering the softening point by Li2〇 is the largest. The content is from 1 to 10% by weight, preferably from 3 to 9%, more preferably from 5 to 8.5 %. . However, since the phase separation property of L^〇 is strong, when a large amount is added, the liquidus temperature becomes high and the workability tends to be deteriorated. Further, since the LhO field strength (hereinafter referred to as F.S.) is low and the composition of the alkalinity of the glass described later is increased, it is a cause of fusion with the mold during press forming. On the other hand, if L "〇 decreases, the softening point increases.

NhO has an effect of lowering the softening point. When it is contained in a large amount, the amount of volatile matter formed by B2〇3_R, 2〇 increases during melting, and the formation of streaks is promoted. In addition, vulcanization and contamination of the mold are caused during press forming, resulting in a significant reduction in mold life. The content of Na^ is preferably 〇~5%, especially preferably 0.5~3% 〇 Furthermore, in addition to Li2〇 and Na20, ίο may be added to lower the softening point. When adding ίο, the content is preferably 7%~7%, especially preferably 0~5%. When the right Κ 2〇 increases, the weather resistance deteriorates.

La2〇3 has an effect of increasing the refractive index without lowering the Abbe number, so that it is possible to improve the weather resistance without containing a large amount of RO. Further, the U system has the effect of improving the resistance to devitrification and can expand the components of the operating temperature range, but if it is contained in a large amount, the phase separation tendency of the glass tends to be enhanced, and it is difficult to obtain homogenization: glass. The content of La203 is 5 to 15%', preferably 6 to 12%, and further 7 to 10%. Further, it is preferred to adjust the contents of Si〇2 and La2〇3 to 120054.doc 200800830 The mass % is the standard, and the value of SiCVLazO3 is in the range of 3.2 to 15.0, particularly preferably in the range of 3.2 to 1 〇·〇. By setting the ratio to 3.2 to 15 Å without lowering the refractive index, high devitrification resistance can be maintained. When the ratio is small, the devitrification resistance is lowered, and when the ratio is increased, the refractive index tends to decrease. Sb2〇3 can be added as a clarifying agent. However, in order to avoid excessive coloring of the glass, it is desirable to make the content of Sb2〇3 1% or less. Furthermore, 'Ti〇2, Nb2〇5 series increase the refractive index of the glass, but reduce the Abbe number, or increase the absorption of the ultraviolet region, reducing the transmittance of 39〇~44〇11 melon, hindering the use. For short-wavelength lenses, it should be avoided to introduce into the actual break. Further, for environmental reasons, since Ag and halogen are carriers of light color change, it is avoided to Pb0, then 2〇3 and ^2〇3 into the solid glass. Further, in the present invention, "avoiding introduction into the solid glass" means that the content is 0.1% or less. Further, in the optical glass for press molding of the present invention, in order to further prevent fusion of the glass and the mold during press molding, it is desirable to set the degree of glass to 11 or less (preferably 9.5 or less) in addition to the above characteristics. ). Further, in the present invention, the basicity is defined as (the sum of the molar number of oxygen atoms / the sum of the FieId Strength of the cation) xl, and the Field strength (hereinafter referred to as F.S.) is obtained according to the following formula 1. Formula 1, F.S.=Z/r2 Z represents the ion valence, and r represents the ionic radius. Furthermore, the values of Z and r in the present invention use the value of the table (disclosed in the "Scientific Handbook Basics Revision 2]

120054.doc -12- < S 200800830 Edition (issued by Maruzen Co., Ltd. in 1975). According to the invention [Table 1] ί

The opinion of the person is that the lower the degree of verification, the more difficult it is to fuse with the mold, and the mechanism of the alkalinity of the glass is explained.

First, find the number of moles of oxygen atoms. Im〇12Si〇2 contains 2 m〇i of oxygen atoms. Therefore, by the number of oxygen atoms 2 mol multiplied by the mole % of Si〇2 in the glass composition, it can be found that the Si〇2 in the glass has The Zengwa machine η The number of the ear of the milk item is '1' and the number of moles of oxygen atoms of each component is obtained, which is called "the sum of the mole numbers of oxygen atoms". Second, find F.S. The cation si4+ is Ζ = 4, Γ == 〇 4 η ςι = λ ^ Therefore, and Α ·-25. S1〇2 is included! m〇1iSi4+, so Fs in glass • Find 120054.doc -13- 200800830 is 25xl(m〇i)x (% of the moles of si〇2 in the composition). F.S. was obtained for each component, and the total was taken as "the sum of Rs• of the cation". In addition, the value of "the sum of the molar numbers of oxygen atoms" divided by the value of "the sum of the cations of F.S." is multiplied by 1 to be the "glass value alkalinity". Its-person's description of the mechanism by which the glass is judged to govern the fusion. The alkalinity of the glass indicates to what extent the electrons of oxygen in the glass are labeled by the % ions in the glass. In the high-sensitivity glass, the cations in the glass are weakly attracted to the electrons of oxygen. Therefore, when the glass having a high alkalinity is brought into contact with a cation (mold component) having a strong tendency to require electrons, the cation from the mold easily enters the glass as compared with the glass having a low alkalinity. When a cation which is a mold component intrudes (diffusion) into the glass, it is in the glass phase near the interface. The concentration of the mold components will increase. Thereby, the composition of the glass phase and the mold phase is poorly reduced, so that the affinity between the two increases, and the glass is easily attached to the mold. It is generally believed that the glass is fused to the mold because of such a mechanism. Therefore, as the alkalinity is lowered, it is difficult for the mold component to intrude into the glass, and the glass and the mold are not fused. Specifically, it is considered that if the alkalinity of the glass is i i or less, preferably 9 or less, fusion does not occur. When the alkalinity of the glass exceeds 9.5, the mold tends to be fused to the mold. If it exceeds 丨, the glass is fused with the mold, which impairs the surface accuracy of the product and tends to deteriorate the mass productivity. Next, a method of manufacturing an optical reading lens, a photographic lens or the like using the glass of the present invention will be described. After the glass material is blended with the desired composition, Baixuan melts in the glass melt. μ I20054.doc •14- 200800830 Next, the molten glass is dripped from the sputum before the sneeze, Pan, and the company is dripped, and the droplet glass is temporarily prepared to obtain the preformed glass. The bite will be cold-cast and cast. For the glass bricks, the pre-formed glass is obtained by grinding, grinding, and grinding. Next, the mold which was subjected to the precision machining was placed in the center, and the core was placed in a softened state while being heated to a softened state, and the surface shape of the mold was transferred to the glass. This forming method is called (4) die forming method, and it can be applied in general. An optical reading lens or a photographic lens can be obtained in this way. EXAMPLES Hereinafter, the present invention will be described based on examples. [Table 2] _?ιΙΑ121Β201Β€: ο018ΓΟ1ζηο§:ικ2^一/Τ |Quantity I

03 a2 : / L Refractive index nd Abbe number vd Bearing phase temperature m Weather resistance ί Transmittance difference ΔΤ0/γΛ Alkalinity 7Η3·.73 2.03 1.5887 59.6 599 845 1.5 8.53 250.22.713.09.027.0_7.91.78.0 9.6. L5889 59.6 601 855 1.4 8.58 3 .07.0050 92.525 483.152.6.5.-7.91.210.0.23. 9.4. 1.5851 60.5 602 865 1.3 8.24 4 8.1.73.0-0.0.09201.01 431428527.1.8.0.159.6· 1.5855 60.1 605 844 L1 8.34 120054.doc -15- 200800830 [Table 3] 5 6 Composition (% by mass) Si02 51.0 49.0 A!2〇3 0.7 2.5 B203 13.0 13.0 CaO 5.0 - BaO 5.0 8.0 SrO 9.0 9.0 ZnO .- 2.7 Li20 6.4 7.5 Na20 2.7 0.9 La2〇3 7.0 7.4 Sb2〇3 0.2 - RO 19.0 17.0 R,20 9.1 8.4 Si〇2/La2〇3 7.3 6.6 Refractive index nd 1.5837 1.5851 Abbe number vd 60.5 60.4 Softening point (°C) 617 606 Liquid phase temperature (°C) 866 840 Weather resistance (difference in transmittance ΔΤ%) 4.5 3.1 Residual 'degree 8.36 8.36 120054.doc 16- 200800830

[Table 4] 7 8 9 10 Composition (mass °/〇) Si02 43.1 50.0 48.6 42.0 AI2O3 4.5 3.0 3.5 4.8 B2〇3 15.0 15.0 13.5 16.0 CaO 4.0 2.0 1·3 0.6 BaO 9.0 6.0 9.0 9.0 SrO 4.8 4·0 4.0 8.0 ZnO 3.0 1.0 3.0 3.0 U20 7.5 9.0 8.0 8.0 Na20 1.0 0,5 1.0 - La203 8.0 93 8.0 8.4 Sb2〇3 0.1 0.2 0.1 0.2 RO 17.8 12.0 14.3 17.6 r'2o 8.5 9.5 9.0 8.0 Si〇2/L^2〇 3 5.4 5.4 6.1 5.0 Refractive index nd 1.5959 1.5830 1.5859 1.5962 Abbe number vd 59.3 60.7 59.9 59.6 Softening point (°C) 601 600 604 598 Liquid temperature (°C) 868 858 845 852 Financial 1.5 1.3 1.1 1.2 (Transmission Rate difference ΔΤ%) Test 8.40 8.23 8.36 8.26 120054.doc 17- 200800830 [Table 5] 11 12 13 Composition (% by mass) Si02 553 46.8 41.0 AI2O3 1.7 1.6 4.0 B2O3 7.2 7.4 15.0 CaO 4.2 9.7 5.0 BaO 9.6 - 10.0 SrO 5.0 5.0 ZnO 5.0 3.0 5.0 L12O 9.8 7.0 2.5 Na20 2.0 4.9 4.9 La2〇3 52 14.6 7·6 Sb203 - Multiple RO 13.8 14.7 20.0 R, 2〇11.8 11.9 7.4 Si〇2/La2〇3 10.6 3.2 5.4 Refractive index nd L5821^_ 1.6061 1.5948 1 habe number vd 58.7 56.6 58.6 softening point rtn 576 599 64 8 欣 温 温 875 875 887 838 蚵 ( ( ( ( ( ( ( ( ( ( ( 1.6 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 And Table 3 shows a comparative example (sample No. 5 to 6). Each sample was prepared as follows. First, a glass raw material was prepared to have the composition shown in the table, using platinum rhodium at 1400. The crucible melted for 3 hours. After melting, the melt was poured onto a carbon plate, and after annealing, a sample suitable for each measurement was prepared. The obtained sample was measured for its refractive index (nd), Abbe number (vd), and softening (s) weather resistance. Also, calculate the degree of verification. These results are shown in the tables. As shown in the table, the implementation of the present invention, 120054.doc -18-200800830 of each sample of 7 to 13 has a refractive index of 1.5821 to 1.6061, an Abbe number of 56.6 or more, a softening point of 648t or less, and a liquidus temperature of 887. 〇C below. In addition, the change in transmittance before and after the exposure test of the ancient, the sho, and the shovel was as small as 16%, and it was considered to be good as well. Further, it contains a large amount of Η2.3, and the degree of verification is also less than 9 55, so that it is difficult to cause fusion with the mold. On the other hand, in each of Comparative Examples No. 5 and No. 6, the transmittance change before and after the exposure test was as large as 3.1% or more, and the weather resistance was low.

Further, the refractive index (nd) is expressed as a measured value for the 丄 line of the xenon lamp. The Abbe number (vd) is the value of the refractive index of the above-mentioned d-line refractive index and the hydrogen lamp ο%.] nm), the same hydrogen lamp C line (656.3 nm), according to the Abbe number (vd). ={(nd-l)/(nF-nC)} is calculated. The softening point was measured by a fiber elongation method according to Japanese Industrial Specification R_31〇4. The liquidus temperature TL is measured by the following steps, that is, the sample is pulverized into a powder of 297 to 500 μm and classified, placed in a platinum boat, and maintained in an electric furnace having a temperature gradient for 24 hours. Cooling was placed in the air, and the devitrification precipitation position was obtained by an optical microscope. Evaluation of weather resistance, the glass transmittance before and after the exposure test in the high temperature and high humidity state was measured by a spectrophotometer, and the difference in the glass transmittance at a wavelength of 59 〇 nm in the visible region was evaluated. Furthermore, the exposure test was performed at a temperature of 6 Torr. The enamel, the wetness is 90%, and the conditions of 300 hours are carried out. The glass sample is polished to a size of 3〇χ25, and the two sides are firstly ground to obtain 1〇mnU^ degree. The alkalinity is calculated according to the formula (the sum of the moles of oxygen atoms / the sum of the cations iField strength 120054.doc -19- 200800830) Χ 100

Recorded as F.S.) by the following formula.

Strength (the following FS=Z/r2 Z indicates that the ion valence number 'is broadly expressed as the ionic radius. However, it is clear to those skilled in the art that various modifications can be applied and the present invention will be described in detail with reference to specific embodiments. The spirit and scope of the present invention Under the conditions of this application, or the amendments. This application is based on the patent application filed on April 5, 2006, the patent application (the patent application 2006-103806), and the patent application filed on March 29, 2007 ( Japanese Patent Application No. 2007-86412), the contents of which are incorporated herein by reference.

Claims (1)

200800830 X. Patent application scope: 1 . An optical glass for press molding, characterized in that it contains 41% to 56% of SiO 2 , 1 · 5 to 5% of a 1203, 7 to 16 by mass%. /. B2〇3, 〇·1~10% of CaO, 0~10% of BaO, 〇~10% of SrO, 0~5% of ZnO, 1~ι〇〇/. Li2〇, 〇~5% Na2〇 and 5~15% La203. 2. The optical glass for press molding according to claim 1, wherein the total amount of Li2〇 and Na2〇 is 5 to 12%.光学'3. The optical glass for press molding of claim 1 or 2, wherein the total amount of CaO, BaO & Sr0 is 10 to 20%. The optical glass for press molding according to any one of claims 1 to 3, wherein substantially no TiO 2 & Nb 205 is contained. The optical glass for press molding according to any one of claims 1 to 4, wherein the content of SiO 2 and La 203 is 3.2$ SiO 2 / La 203 $ 15 · 以 based on 篁 %. I20054.doc 200800830 ' VII. Designated representative map: (1) The representative representative of the case is: (none) (2) The symbolic symbol of the representative figure is simple: 8. If there is a chemical formula in this case, please reveal the characteristics that can best show the invention. Chemical formula: (none) 120054.doc