TWI359121B - Optical glass, preform for precision press molding - Google Patents

Description

1359121 IX. Description of the Invention: [Technical Field] The present invention relates to an optical glass having an index of refraction (nd) greater than or equal to 1.65 and an Abbe number greater than or equal to 50 (Abbe mimbeO (nu) d) an optical constant of the form; a preform for precision press molding composed of the glass; a method of producing the preform; and a method of manufacturing an optical element comprising the glass. [Prior Art] The advent of digital cameras and mobile phones equipped with cameras has led to rapid progress in high integration and high functionality in devices employing optical systems. ^ This same, the demand for high-precision, low-weight, compact optical systems is rising. In recent years, in order to meet these demands, the optical design using non-spherical lenses is gradually shifting to the mainstream. Therefore, in order to stably and economically provide a large number of precision pressurization techniques (also referred to as molded optical molding techniques) that directly form an optical functional surface by press molding without a grinding or polishing step using highly functional glass Attract attention. The demand for optical pressure glass with low temperature softening is increasing every year. These glasses include a refractive index and a low-dispersion glass having an Abe (6) greater than or equal to i 65 and an Abbe number greater than or equal to 5 G. Examples of high- and low-dispersion glass having low-temperature softening properties are described in No. 2,616,958. - Spears are used in the manufacture of optical components such as precision twisted lenses.

S 319107 1359121 I ‘In the case of this glass-like precision press molding, sometimes damage occurs during the cooling process of this addition. These damages are made up of fine lines (five) z. This is particularly remarkable in the above-mentioned high refractive index and low dispersion glass, and the yield is jeopardized. Under the circumstance, the inventors of the present invention have an object to provide a means for producing an optical element comprising a high refractive index and a low dispersion glass by high pressure production through compression molding. The inventor of the present invention carefully studied the causes of the fine lines and cracks described above and now described below: Less than precision press molding, after the glass is formed into a desired shape in the dusting mold, the glass is Maintained in the pressurizing mold, the mold is kept dense so that the glass surface retains the shape transferred by the surface of the mold while being cooled to a temperature range in which the glass does not deform. At this point, the portion of the glass attached to the surface will cool rapidly' but the center and portion of the glass cool slowly. Thus, even after the glass near the surface has reached a temperature below the glass transition temperature, the flux at the center is still above the glass transition temperature. When the inventor of the present invention explores the swelling properties associated with conventional glass which is prone to fine lines and cracks, the linear thermal expansion coefficient ratios above and below the glass transition temperature are significantly souther than those which are less prone to fine lines. And the linear thermal expansion coefficient of the cracked glass. Also in this glass, when the temperature near the surface is lower than the glass transition: degree and the temperature of the center is higher than the glass transition temperature, the central portion is farther than the portion near the surface. Big contraction. This phenomenon occurs when the glass is enclosed in a pressurizing mold, and a large stress is generated in the glass which loses the ability to undergo the deformation of the plastic 319107 6 1359121. At the time of the coil, even when stress is generated, it does not;: Damage = firmly: ^ The structure of the high refractive index and the low dispersion glass which are relatively weak in the optical constant range described above is considered to cause fine Grains and cracks. 'Therefore, when this (four) Ming people _ these hairdressing lines further research, they found that through the traditional high refractive index and low dispersion glass above and below the glass transition temperature expansion coefficient The reduction between the differences can reduce the difference in the degree of contraction between the surface near the surface and the center of the heart during the cooling step, thereby suppressing fine lines and cracks. The present invention has been designed on the basis of this. The inventor of the present invention provides an optical glass which is not damaged in precision press molding, a preformed product for precision press molding composed of the glass, and an optical component composed of the glass. . In addition, the inventors of the present invention have contributed to the manufacture of optical elements at high productivity without damaging the glass. The invention relates to an optical glass for precision press molding, which has a refractive index greater than or equal to 1.65 and an Abbe number greater than or equal to 5 汕 to match number) (nu)d ) such that the ratio of α(Μρ/]3)1/α(3^^)2 is less than 17, which will be expressed in the temperature range from the glass transition temperature (Tg) to the relaxation temperature (Ts) The temperature table for this maximum glass elongation difference relative to the temperature difference Δ (MX7M)T (here the table or smaller fixed value) is T1 and will range from T1-56C to T1 + 5°C. The average linear expansion coefficient within the table is "rushed alt and will be from 319107 7 1359121 from the glass transition temperature (Tg) - 16 (rc to the glass transition temperature yield ag) - i4 (the average linear expansion in the rC range Coefficient table = 地 纟 it it 〃 〃 〃 〃 〃 〃 〃 〃 〃 〃 〃 〃 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密 精密Other exemplary embodiments and advantages of Qian Ming can be determined by reading the contents of the disclosure and the drawings. Therefore, the following specific examples are to be understood as merely illustrative, and in no way limit the remainder of the disclosure. In this regard, it is not intended to show more detail than those required for a basic understanding of the invention. The invention will be described in detail in conjunction with the description of the drawings, and it will be apparent to those skilled in the art how to practice several embodiments of the invention. The invention will be described in more detail below. [Optical Glass] I Invented Optical Glass is an optical glass for precision press molding having a refractive index (nd) greater than or equal to 1.65 and an Abbe number (in nu) d of greater than or equal to 5 ,, such that α(1) coffee The ratio of 1/α (suppressed) 2 is less than 17', which will exhibit a difference Δ (/^XM) with respect to the temperature range from the glass transition temperature (f) to the sag temperature (Ts). The temperature at which T (where Δ (/) appears to represent a fixed value of 1 〇c or less) is expressed as τ] and will be from Tl-5 C to T1+5°. The average linear expansion coefficient in the range C is not shown and will be converted from the glass Degree (Tg)_16 (rc to the glass transition (8 319107 1359121 benefit (Tg) - 140 ° C. The average linear expansion coefficient is expressed as aip /? a2. The ratio a (aip /? a) 2 is An index of the difference between the expansion coefficient higher than the glass transition temperature and the expansion coefficient lower than the glass transition temperature. As described above, in the present invention, in the high refractive 'rate and low dispersion glass Internally, reducing the difference between the expansion coefficient above the glass transition temperature and the expansion coefficient below the glass transition temperature can reduce the difference in shrinkage between the glass surface and the interior of the glass during cooling. 'This suppresses fine lines and cracks. The ratio a(aJp/ja)l/a(aJp/ja)2 will be described below. The coefficient of thermal expansion a7p/jal is expressed in the temperature range from the glass transition temperature (Tg) to the sag temperature (Ts), which is expressed relative to the temperature difference (here /) £X7Mt expressed or smaller The fixed value of the maximum glass elongation difference is expressed by T1, the average linear expansion coefficient in the range of n-5 ° C to Τ 1 + 5 · ;; which is representative of the transition from the glass _ The value of the linear expansion factor in the temperature range (Tg) to the sag temperature (Ts). The average linear expansion coefficient is from a temperature lower than the glass transition temperature (Tg) of 160 ° C (Tg - 160 ° C) to a temperature lower than the glass transition temperature (Tg) 140 ° C (Tg-14 (TC) Average linear expansion in the range

Coefficient; which is the value representing the linear expansion coefficient at a temperature below the glass transition temperature (Tg). V The glass transition temperature (Tg) and the relaxation temperature (Ts) are

The thermomechanical analyzer manufactured by Rigaku Denki K.K. is measured at a temperature increase rate of 1 gram load and 319107 9 1359121, for example, '4 °G/min. The coefficient of thermal expansion, a; p, such as 2), can be calculated from the results of the thermomechanical analysis obtained using the apparatus. When the ratio aip/?al/a^/?a2 in the optical glass of the present invention is lower than the value of the 1717 field, the difference between the shrinkage and the shrinkage between the surface and the inside of the glass will be Increases in the cooling step, which may cause fine lines and cracks. The ratio Wp/^l/a; p/3a2 is suitably 16 5 or lower, preferably 16 • or lower and more preferably 15 or lower. The smaller the difference between the expansion coefficients above and below the glass transition temperature, the better the suppression of the fine lines and cracks. However, as far as the properties of the glass are concerned, for example, 丨 is greater than p/?a 2, and η is used for the tm point, and the lower limit of the ratio a jphal /a Jpha 2 can be regarded as 1 · 01. In the case of a glass which satisfies the properties described above, the ratio of 3 work / ^ 1 / 34 is suitably 2.5 or higher. The typical components that improve aip/jal are 匕(1) and Ca0. The typical components that reduce a/p/?al are Si〇2 and LhO. From the point of view of influencing the a;p/jal, the effects of Collapse_ Law and GchO3 fall between Si聊4 Li2〇 on the one hand or (10) to the other. For example, (10) or (10) may be replaced with 〇2 or LiA to reduce a1, and substitutions in the other direction may be used to increase Wp/jal. The amount of change in the ayp such as 1 can be controlled by this substitution. It is also possible to replace La2〇3 and Gd2〇3 with B2〇3 or Ca〇 or Bz〇3 or Ca〇 with La2〇3 and Gd2〇3 in the same manner, and

Si〇2* Li2〇 replaces La. and Gd2〇3 or replaces Si〇2 or Li2〇 with La2〇3 and Gd2〇3. A7p/^2 can be raised by increasing the 319107 10 121 121 having a large ionic radius in the glass' and by increasing the decrease with a small ionic radius. For example, regarding divalent cation components:

The ionic radius of Ba > the early s of the Sr, the irradiance of the 丄r ion, the ionic radius of the Ca > the radius of the dimension of the Mg > the ion of the Zn is τ ^ τ. • The yak heart. The ionic radius of u and Li is greater than Ca. Ion of Ca; 0. , λ., « II; ionic radius of B*si. For this reason, the substitution of these elements with each other can be used to control aip/^2. • The method described in (4) may be such that the ratio 肇 _ _ 2 is kept below 17 在 in the towel composite of the present invention. However, from the viewpoint of controlling the ratio a (10) a 〜 咖 2, _al has a greater influence than a 2 , and The degree of this change achieved by the above substitution is relatively large for two ports. Therefore, the ratio is called / it is appropriate to control and control aw31 via L. For example, the range is preferably from 5〇χ1〇-6 to 200χ10-νγ, and a; the range of can a2 is preferably from 50χ1 (Γ7 to 20〇xl〇-7/°c. Due to the optical glass of the present invention It is used for precision press molding, so its glass transition temperature is preferably lower than or equal to 63 (rc. However, at a glass transition temperature lower than 4 〇〇:c, it sometimes becomes difficult to evaluate Wβ. In addition, during the press molding process, a carbon-containing coating is formed on the surface of the preform to help the glass to stretch, and there is also a risk of clogging. Thus, the glass transition temperature is preferably from 450 to 63 (TC, preferably. 450 to 620 ° C. Further, the optical glass of the present invention preferably has a lower than or equal to 67 ° C, preferably 490 to 66 (TC, more preferably 500 to 64 (TC, and even better) a sag temperature of 530 to 630 ° C. When the optical glass has a low glass transition temperature and a sag temperature, the glass may be heated to a temperature of 319107 11 1359121 in press molding. The result is heating and cooling the glass. The time required is shortened and the yield in the manufacture of press-formed products can be increased. The heating temperature of the press molding can be extended, so that the life of the press molding die can be extended. The optical glass of the present invention has a refractive index (nd) of 1.65 or more and an Abbe number (nud) of 50 or more. The upper limit of the refractive index and the Abbe number of the inventive glass is particularly limited. However, the low temperature softening property and glass suitable for press molding are important for the formation of the high quality preform. For stability considerations, it is preferred to have a refractive index (nd) of 18 or less and/or an Abbe number (nud) of 60 or more. Next, a suitable composition of the present invention will be described. The optical glass of the present invention may comprise It is a glass component in the form of B2〇3, Si〇2, La2〇3, metal oxide, and divalent metal oxide. The following § brothers clarify the individual glass components. Unless there are different specific descriptions, the content and combination The content is the percentage of Momo, and the ratio of the content to the combined content is the molar ratio. B2〇3 and Si〇2 are all components for forming a glass network. In order to strengthen the structure of the glass and reduce fine lines and cracks, The Si()2 content is (4) 3 The ratio of the amount (10) 2 / B2 〇 3) is preferably from 〇 1 to 〇 9 〇. When the refractive index (nd) is from 1.65 to 1.70, the content of the s pool relative to the sol can be increased to strengthen the structure of the glass. So, Si〇2/ secret should be more than Q 5 but not more than G.9G' is better than G 5 but not more than 0.5 but not more than 〇· 文住, u. 8 and better from 0 55 to 0.75, the range of X is better from 〇55 to 〇7. When the refractive index (10) 319107 12 U59121 exceeds 1.70, S1〇2/B2〇3 is preferably 〇5, The best 〇 ^ to 0.4 to maintain the desired nature. (10) is a component which imparts a high refractive index to glass and is used to increase the chemical durability of the glass. Gd2〇3, γ2〇3, and Yb2〇3 which function in the same manner as the La2〇3 can be added as an optional component. The U2()3 and at least one selected from

The addition of oxides in Gd2〇3, Υ-, and Yb2〇3 is suitable for increasing the high temperature stability of the glass. Alkali metal oxides are used to impart low temperature softening properties. In this respect, the U-phase adds a low-temperature softening property while increasing the refractive index of the glass. In this respect, Ll2〇 has a greater utility than other metal oxides as long as it is not added to the excess. Thus, the loss of devitrification resistance or chemical durability can contribute to the desired refractive index and low temperature softening properties.

Zn〇' which imparts a low-temperature softening property while increasing the refractive index of the glass and MgO, Ca0, Sr0, and _ for adjusting the optical constant can be added as a divalent metal oxide. In the compositions of the present invention, it is sufficient to add Sb2G3 which can be added as a 'and a clear agent as needed to obtain a composition which simultaneously achieves the above-mentioned properties f. The content of each component is preferably within the range described below. Both 匕〇3 and SiQ2 are network-shaped secret components. In order to increase the stability of the glass, the combined amount of the two components (Si() 2 lion 3) is preferably 5 〇 to 72% 'better 5 〇 to 7 〇 %, more preferably 5 〇 to 68%, and Even better, 5〇 to 65%. The ratio of the content of b1〇3 to b2〇3 (Si〇2+B2〇3) is preferably maintained at 319107 13 1359121 as described above to promote the outflow viscosity of the glass melt to be more suitable for the preform. The molding and improved chemical durability simultaneously strengthen the glass bond, 'reducing the change in viscosity with respect to temperature, solving the problem of the glass crack and maintaining the low temperature softening property. The content of the Si 〇 2 is combined with the Β 2 〇 3 content and is also defined based on the ratio of the Β 2 〇 3 content. However, when the refractive index (nd) is from /65 to 丨.70, the content of the S1〇2 is preferably 15 to 30%, preferably 18 __ to 30% 'better 18 to 27 %, and more preferably, 19 to 25% β When the refractive index (nd) exceeds 1.70, the content of the Si〇2 is preferably 4 to μ18% 'better 5 to 16%' and more Good, 6 to 15%. The cerium-containing cerium is also defined in combination with the si 〇 2 content and also based on the ratio of the Si 〇 2 content. However, when the refractive index (nd) is from 1.65 to 丨.70, the content of the B2〇3 is preferably from 25 to 45%, preferably from 30 to 40%, and more preferably from 32 to 37%. . When the refractive index (nd) exceeds 丨.7〇, the content of the B2〇3 is preferably 38 to 6 8%, preferably 42 to 65%, 4 and more preferably 44 to 62%. In contrast to other metal oxides, Li2〇 can increase the refractive index more and lower the glass transition temperature without compromising chemical durability, thereby enhancing the refining properties of the glass. However, these effects are difficult to achieve when introduced in excessive quantities. In addition, when introduced in an excessive amount, the devitrification resistance of the glass is reduced, and it becomes difficult to directly mold the glass melt from the outflow into a high-quality preform, and the weatherability is deteriorated. . Therefore, when the refractive index (nd) is from 1.65 to 1.70, the content of the LizO is preferably maintained at 5 to 20%, preferably J4 319107 1359121 is 6 to 18%, and more preferably , 9 to 18%. When the refractive index (nd) exceeds 1.70, the LhO content is preferably from 1 to 14%, preferably from 2 to 12%, and more preferably from 3 to 11%. In addition to Li2〇, Na2〇 and K2〇 can be added as metal oxides. However, 'when considering the effect of Li2〇 described above, regardless of the refractive index, the ratio of the Li2〇 content to the combined content of Li2〇, Na2〇, and K2〇R, 2〇• (Li2〇/ R, 2 〇) is preferably 〇. 8 to 1, preferably j. In order to maintain the stability and chemical durability of the glass, regardless of the refractive index, the ratio of the R 2 〇 content to the combined content of S i 〇 2 and B 2 O 3 (R′ 2〇/(Si〇4B2〇3)) is preferably Y is less than 〇. 3, preferably less than 〇. 29.

La2〇3 has the effect of increasing the refractive index and increasing chemical durability and weather resistance without lowering the stability of the glass or increasing the dispersion. Therefore, it is an essential component of the glass of the present invention. This equivalent is not achieved when added in too small amounts. When added in an excessive amount, the glass stability is lowered, the glass transition temperature is increased, and both of the high-quality preforms and the precision press molding become difficult, and the dispersion is increased. Therefore, the Laz〇3 content is preferably 〇. 5 to 22%, preferably! To 5%. When the refractive index (nd) is from 165 to 17 Torr, the content of the 〇3 is preferably from 2 to 10, preferably from 3 to 10%. When the refractive index (nd) exceeds 17 Torr, the U2 〇 3 content is preferably from 5 to 15, more preferably from 6 to 14%. . θ Gd203 can be used as an optional component. In the same manner as the La2?3, it can increase the refractive index without impairing the stability or low dispersion property of the glass. Second: Addition: durability and weather resistance. In particular, when it is taken together, it can further increase the stability of the glass for devitrification. No 319107 15 When used in the past, it will reduce the stability of the glass, and it is difficult to mold and precision press the preform. Sigh the main text - mouth θ ^ 〇 3 can also be used as an optional ingredient. In the same manner as the Gd2〇3, the refractive index can be raised without impairing the stability or low dispersion property of the glass, and can be chemically durable and economical. In particular, it is possible to further increase the stability of the glass for devitrification when used in combination with La2〇3. When it is used, it will lower the stability of the glass, increase the temperature of the glass transition, and make molding and precision press forming of the preform difficult.

Yb2〇3 can also be used as an optional ingredient. In the same manner as the Gd2〇3 and Υ2〇3, it can increase the refractive index without impairing the stability or low color of the glass, and can increase chemical durability and finance. In particular, 'when it is used with La2〇3, it can further increase the stability of the glass for devitrification. However, when it is used, it will lower the stability of the glass. The temperature is changed and molding and precision press forming of the preform become difficult. Thus, the combined use of GdW, Y2〇3, Yb2〇3 and "these components can increase the stability of the glass for devitrification and effectively promote direct molding from the glass melt into the high quality preform. Therefore, the combined content of the GchO3, Y4, and several 2〇3 is preferably greater than or equal to. However, when the content of the combination is too large, the stability of the glass is lowered and the glass transition temperature is increased. The upper limit of the combined content of Gd2〇3, γ2〇3, and 2〇3 is preferably 15%. When the refractive index (1^) is from 319107 16 1359121 1.70, The combination of Gd2〇3, Υ2〇3, and Yb2〇3 is preferably from 1 to 10%, preferably from 1 to 6%. When the refractive index (nd) exceeds 1. 7〇, it is preferably 3 It is in the range of 14% and preferably 4 to 12%. Among the components such as Gd2〇3, Y2〇3, and Yb2〇3, the components Gd2〇3 and LA are favorable for obtaining the above utility. When the refractive index (nd) is from 1.65 to 1.70, the combined content of the Gd2〇3 - and Y2〇3 is preferably from 1 to 10%, preferably from 1 to 6%, and the refractive index (nd) exceeds 1. 70 o'clock It is preferably from 3 to 14%, preferably from 4 to 12%. The ratio of the combined content of Gd2〇3, Υ2〇3, and Yb2〇3 to the content of La2〇3 ((Gd2〇3+Y2〇3+) Yb2〇3)/La2〇3) is preferably kept within the range of 〇·3 to 1.5 to increase the stability of the glass regardless of the refractive index. When the refractive index (nd) is 丨.邸 to 1.70 At the time, the content of the GchCh is preferably within a range from 〇 to 8% 'better 〇 to 6%. When the refractive index (nd) exceeds 1.70, the content of the Gd2 〇 3 is suitable for falling. From 〇 to 12%, preferably from 1 to 12%, and more preferably from 1 to 1%. + When the refractive index (nd) is from 1.65 to 1.70, the content of Υ2〇3 Preferably, Yulu is from 0 to 5V, preferably [to 3%, more preferably, 〇. i to 2.5%. When the refractive index (nd) exceeds 17〇, The content of LA is preferably in the range of from 1 to 6%, preferably from 0.5 to 6%, and even more preferably from 5 to 5%. 'What is the refractive index, Ybz The content of 〇3 is preferably within a range from 〇 to 5〇/〇, preferably from 〇 to 3%, and particularly preferably not at all.

ZnO is used to lower the sap point, liquidus temperature and glass transition temperature; increase the chemical durability and weather resistance of the glass; and increase the composition of the refractive index. It is preferably employed as an essential component of the glass of the present invention. ZnO is much better than other two 319107 17 1359121 valence components to enhance the weatherability of the glass. In this case, Ba0 - although the refractive index can be increased, it will impair the weather resistance of the glass. Therefore, ZnO can be added in demand to replace _. In order to achieve the effect of the grain by doping, when the refractive index (nd) is 165 to i ,, the amount of ZnO is preferably 5 to _, preferably 6 to eagle, and more preferably -7 to 20%. When the refractive index (ml) exceeds 1.70, the content of Zn〇 is preferably from 1 to 18%, preferably from 2 to 16%, and more preferably from 3 to 14%.

MgQ, (10), SrG, and _ are all used to adjust optical constants. The CaO content of 1 is preferably from 〇 to m to achieve the desired target regardless of the refractive index. This CaO is used in conjunction with Training 2 and β2〇3 to lower the glass transition temperature. Therefore, the amount of CaO added is preferably 1% or more, preferably from (1) to (14). Further, when the refractive index (10) is 165 to Å, the divalent component 'including Zn ruthenium is not appropriately blended with the alkaline earth metal compound, and it becomes difficult to attain a glass having good weather resistance. 5的以上。 The ZnO content of MgO, Ca0, Sr0, and Ba 〇 of the combined content of r 〇 ^ the ratio (sub / RO) is preferably 0. 5 $ greater. A preferred Zn〇/R〇 ratio is from 0.5 to 4, and even more preferably from ο” to 3. Regardless of the refractive index, the combination of Mg0, Ca〇, Sr〇, and ytterbium is preferably from 1 to 14%, preferably from 2 to 14%, to adjust the optical constant and lower the glass transition temperature. Regardless of the refractive index, it is desirable to pay attention to the incorporation of MgO, Ca0, Si*0, and BaO to simultaneously lower the glass transition temperature and achieve good pairability. As described above, when added in an appropriate amount, (10) is used to lower the glass transition temperature. Since the incorporation of Ba〇 will impair the weatherability, the ratio (CaO/RO) of the content of 319107 18 1359121 is preferably 0.5 to j, and 2 to 8 8 to The ratio (Ba0/R0) of the R〇 content is from 0 to 〇·2, and particularly preferably 〇. As described above, although Ba 〇 can increase the refractive index, it also reduces the weather resistance of the glass, i.e., weakens chemical resistance. In the present invention, regardless of the refractive index, the Ba〇 content can be controlled to be

The ratio of the combined content of other components in the form of Gd2〇3, Y2〇3, and Yb2〇3 which can increase the refractive index is such that the desired refractive index is achieved, and even BaO denier is not added. That is, you can save Ba〇. When it is added, it is preferable to reduce the amount of (4) such that the combined content of LazO3, Gch〇3, Y2〇3, and Yb2〇s is the ratio of the content of the BaO ((La2〇3+Gd2〇) 3+Y2〇3+Yb2〇3)/BaO) is

1 〇 or greater. In this way, an optical glass having both the desired optical properties and good chemical resistance can be achieved. When BaO is added, the ratio ((La2〇3+Gd2〇3+Y2〇3+Yb2〇3)/BaO) is preferably 11 or greater, and preferably 12 or greater is better. 15 or greater 'and better, 18 or greater.

Sb2〇3 is an optional additive as a fining agent. Since sufficient effect can be attained at 1% or less, the content is preferably from 〇 to 1%, preferably from 〇 to 0.06%. The addition of the excess Sb2〇3 oxidizes the molding surface of the press molding die in precision press molding, adversely affecting the service life of the press molding die and the like, and thus from the precision press molding The point of view is not suitable. A12〇3 has the effect of enhancing the durability and weather resistance of the glass and can be added as an optional ingredient. However, at temperatures above 5%, the glass 319107 19 1359121 transition pulse will increase sharply and will cause the optical constant to fall outside the desired range. % of the risk, 0 to 5% of the Ah 〇 3 content is suitable, preferably [to 3% and even better, 0 to 2%. • (4) 2 can be used as an optional component to increase the viability of the glass and adjust the fresh constant. However, when the content exceeds 5%, there is a risk that the optical constant number falls outside the desired range and the low temperature softening property is sub-ized. For this reason, regardless of the refractive index, the content of the present invention is preferably. To 5%, preferably. · (4). In the glass

Ta2〇. W〇3, palpitations 5, Ti〇2, P2〇5 and F can be incorporated to the extent that the objectives of the present invention are not lost. However, considering the cost of the starting material's influence on the various properties of the glass, and the productivity, these compounds must be controlled. Ta2〇5, W〇3, Nb2〇5, Ti〇2, P2〇5, and &, and a3 is less than 5%, preferably less than 2%, and more preferably less than, And even better, below 〇.5%, the best is not mixed at all. Therefore, it is preferable not to add because it causes difficulty in directly molding a high-quality preform from the glass melter b body.来看 For the negative impact of the environment, avoid adding Pb, Cr, Cd, A^^Th, and Te. Pb is conventionally used as a main component of optical glass to improve the refractive index, but in addition to the problems described above, it tends to be reduced by precision press molding in a non-oxidizing gas environment. This causes the precipitated metallic lead to adhere to the molding surface of the press molding die, thereby reducing the problem of the surface precision of the press-formed product.杬2〇3 is also conventionally added as a clarifying agent. However, in addition to the problems described above, it causes oxidation of the molding surface such as a press molding die, thereby shortening

(S 319107 20 1359121 The use of the converter is problematic and therefore should not be added.) The invention of the glass can be produced by heating and melting the glass starting material. It may be in the form of a suitable carbonic acid step, a sulphate, an oxide, and the like. These starting materials are weighed and mixed in a predetermined ratio to obtain a blended starting material. - the starting material is placed in a furnace, for example, i, to 13 (10). The starting material is then dashed, clarified, dropped, and sentenced to give a uniform glass without bubbles and undissolved matter (4) The glass of the present invention is molded and gradually cooled to obtain the optical glass of the present invention. [Preform for fine press molding and method for producing a preform for precision dusting molding] ' - 帛The preform for precision press molding of the present invention and the method for producing the preform for precision press molding are described. The preform used for precision press forming can be referred to as "precision press molding". Preform, or simply The preform, the preform is a molded glass member that is equal in weight to the precision twisted two-in-one article. The preform is molded into a shape corresponding to the shape of the precision press-formed article. Examples are a spherical shape and a convoluted spheroid. The preform is heated to a viscosity which facilitates precision press molding and is subjected to precision press molding. The preform used in the precision press molding of the present invention is The optical glass of the present invention is constructed. The surface of the preform of the present invention may be provided with a thin release blunt as needed. The preforms can be molded with high precision to produce desired optical constants with high productivity. An optical component. Alternatively, as described above, the glass composition can be adjusted to increase the glass

319107 21 1359121 The stability of the glass over the surface temperature range and the viscosity of the glass melt in the outflow. Thus, in the procedure of cooling a glass gob which separates a glass melt from a tube, the method of molding the preform can provide for the manufacture of the high quality preform at high productivity. The present invention also relates to a method of making a preform for precision press molding, comprising: (1) determining a glass composition to impart a refractive index (nd) greater than or equal to 1.65 to greater than or equal to 50. The Abbe number (nud), and a ratio of apl/?al/aip/7a2 of less than 17, which will be expressed over the temperature range from the glass transition temperature (Tg) to the sag temperature (Ts) The temperature of the difference in the maximum glass elongation relative to the temperature difference (here, a fixed value of 1. C or less) is expressed as T1 and will be from H-5 ° C to T1 + 5 ° C. The average linear expansion coefficient in the range is represented by the rib 1 and will average the coefficient of linear expansion from the glass transition temperature (Tg) _16 (rc to the glass transition temperature (Tg) - 140 ° C. Cut "2", and (2) a preform used for precision press molding using a glass having the composition thus determined. As described above, a7p/3al/a7p/3a2 below Π is used. The ratio can contribute to the reduction or prevention of precision press molding in the south and low dispersion glass Patterns and cracks. In the method of the present invention for producing a preform for precision press molding, the composition is determined such that the ratio is less than 17 to promote high productivity and/or presence in precision press molding. Fine-formed glass of crepe and crack to produce a preform for precision press molding. The preform used for precision press molding thus produced can be used for high-productivity manufacturing with (4) 319107 22 1359121 Optical element composed of high refractive index and low dispersion glass of optical constant. The aip/jal/a7p/ja2 ratio is achieved by the control method described above. Preform for the manufacture of precision press molding according to the present invention. In the method of the method, these control methods may be appropriately combined to determine a glass composition which produces an aip/2al/ajp/7a2 ratio of less than 丄 7. The preform may be produced by a method comprising the following steps: · causing the glass melt to flow out of the pipe, separating the glass paste balls, and cooling the glass melt paste balls to form a preform for precision press molding ( It is referred to herein as a method; and is produced by a method comprising the steps of: molding a glass body from a glass melt and cutting or slicing; grinding; and polishing the molded glass body (hereinafter referred to as "method 2" ) μ

A specific example of the method 1 is a production method in which a preform having a predetermined weight is molded by separating a predetermined weight of the glass (tetra) body paste ball from the outflowing glass (tetra) body stream and cooling the glass paste ball or the like. The advantage of this method is that it does not require mechanical reinforcement such as cutting, grinding, and light removal. The machined preform needs to be annealed prior to machining to reduce the deformation of the domain to the point where damage does not occur. However, the method described above does not require annealing to prevent damage. In addition, it can give a preform having a brilliance surface. In this method, from the viewpoint of imparting (four), a clean surface, it is preferable to form the preformed object by floating under the application of wind pressure. Does not contain cutting marks, called cut marks. Shearing occurs when the outer flow glass (4) melt is cut by the blade. When the shear = is retained by this stage of the molded precision twisted molded product, = 319107 23 1359121 becomes a defect at the end. Therefore, it is preferable to eliminate the cutting mark at the preforming stage. A method of separating a glass melt that does not produce a shear mark comprises dropping a glass melt from an outer tube, and supporting a front end of the glass melt flowing out of the outer tube and contributing to a glass melt paste having a predetermined weight This support is removed at the timing of the ball separation (referred to as the "drop-cut method"). In the drop-cutting process, the glass is separated by a constriction formed between the front end of the flow of the glass melt and the tip of the outer flow tube to produce a glass melt paste ball having a predetermined weight. . Next, the obtained glass melt paste ball was molded into a shape which was suitable for press molding while still being softened. In the method 2, the glass melt is flowed into a casting mold to mold the molded glass member including the optical glass described above, and the molded glass member is machined to be formed into a preform having a predetermined weight. Things. The glass is preferably subjected to an annealing treatment prior to machining to completely remove residual deformation. [Optical element and method of manufacturing the optical element] The optical 70 of the present invention is composed of the optical glass of the present invention described above. The optical element of the present invention is characterized by having a high refractive index and a low dispersion property in the form of the optical glass of the present invention constituting the optical element. Examples of the optical element of the present invention are various lenses such as a spherical lens, an aspheric lens, and a microlens; a diffractive optical thumb; a lens with a diffractive peach; a lens array; These optical elements are preferably obtained by heating & softening and precision press molding the preform of the present invention. An optical film such as an anti-reflection film, a total reflection film of 319107 24 1359121, and a partially reflective film may be attached to the optical element. And films with spectral properties. The method of manufacturing an optical component is described. In the method for producing an optical element of the present invention, the preform used in the method of pre-forming a preformed method of the present invention by the method of the present invention is heated and used to manufacture an optical transfer/ = Precision press forming dies are precision pressed. This precision press molding method, also referred to as a molded optical molding method, is well known in the art. Any surface of an optical element that x can transmit, refract, diffract, or reflect light is referred to as an optically functional surface. In the example of the lens, both the aspherical surface of the lens surface = the aspheric surface of the aspherical lens and the spherical surface of the spherical lens correspond to the optically functional surface. In precision press molding, the forged plastic surface of the precision press molding die is precisely transferred to the glass to form an optically functional surface via press molding. That is, in order to complete the optically functional surface, no mechanical processing such as grinding or polishing is required.

Therefore, the method of manufacturing an optical element of the present invention is suitable for fabricating optical elements such as lenses, lens arrays, diffraction gratings, and prisms, and is most suitable for manufacturing aspherical lenses with high productivity. The method of making an optical component of the present invention can facilitate the fabrication of the optical component having the optical properties described above and permit adjustment of the glass composition described above to impart low temperature processing properties to the preform, thereby facilitating the entry at relatively low temperatures. Press molding of glass. Thus, the load on the molding surface of the press molding die is reduced and the use of the press molding film (or the release film when the release film is attached to the molding surface) can be extended. Shou 25 319107

丄J Qualitative, tempering and tempering enhances the composition of the glazed material to stabilize the devitrification. The ground is reheated and the good fortune is prevented. The glass step "ίπ_ (4) glass is obtained by obtaining the final product. The series of steps can be performed with high productivity. The known pressure forming mold can be used for precision forming, such as = for example, carbon cutting (four), super hard material or non-axis film can be used. There is a mold surface to be coated with a (four) coating, a demolding, a =3 carbon film, a noble metal alloy film, or the like used. The press molding die is provided with both the upper and lower molds, and if necessary, there is also a In the drum mold, etc., in order to effectively reduce or prevent damage to the glass molded article in press molding, it is preferable to use a press molding die composed of carbon carbide or superalloy (especially A mold made of a superhard alloy without a binder, such as an additive mold made of WC. It is also suitable to add a release film in the form of a carbon-containing film on the molding surface of the mold. It is advisable to use a non-oxidizing gas ring during the molding process. The molding surface of the press molding die is maintained in a good condition. An example of a preferred non-deuterated gas is nitrogen and a mixture of nitrogen and hydrogen. In particular, the use of a carbon-containing film is added. At the time of press molding of the mold surface of the mold film and the use of a press-formed fork made of carbon carbide, it is necessary to perform precision press molding in such a non-oxidizing gas environment. A method which is particularly suitable for producing the optical element of the present invention is used for precision press molding. (Precision Press Forming Method 1) 319107 26 1359121 In this method, 'the preform is introduced into the press molding die, and the pressurization is performed. Both the molding die and the preform are heated, and precision C molding (hereinafter referred to as "precision molding method 1") is performed. • In the fine press molding method 1, it is preferable to add Both the press molding die and the preform are heated to the glass constituting the preform to exhibit a viscosity of 1 〇 to 10 dPa·s for precision press molding. η The precision press molded article is suitable for cooling To the glass Exhibiting from the press molding die when the temperature of the viscosity of io12dpa^s or larger is better than 1% UdPa·s or larger and more preferably 10 dPa·s or more Under these conditions, the shape of the molding surface of the press molding die can be accurately transferred to the glass and the precision press molded article can be taken out without deformation. (Precision Pressing Method 2) This method It is characterized in that a preform heated to a temperature is guided into a press molding mold which is preheated to another temperature, and the preform is precisely pressed (hereinafter referred to as "precision press molding" 2"). This method can be used to preheat the pre-formed material before it is introduced into the press-forming mold. This shortens the cycle time and contributes to good surface accuracy and no surface defects. The manufacture of optical components. The temperature at which the press molding die is to be preheated is preferably lower than the temperature at which the preform is preheated. Such preheating can keep the temperature of heating the press molding die low, thereby reducing wear and tear on the press molding die. In the precision press molding method 2, it is preferred to preheat the preform to 27 319107 1359121. The glass constituting the preform exhibits a viscosity of 1 〇 9 dPa · S or less, preferably 109 dPa · s. . Further, it is preferred to preheat the preform at the time of floating; preferably, the preheating is carried out until the glass constituting the preform exhibits 1〇5·5 to 1〇9

Pa· S, preferably greater than or equal to 105.5 but less than 1〇gdPa·s. The cooling of the glass is preferably started simultaneously with the initiation of pressurization or under pressure. The temperature of the press molding die should be adjusted to be lower than the preheating temperature of the preform. The temperature at which the glass exhibits a viscosity of from 1 〇 9 to 1 〇 12 dPa·s is sufficient as a measure. In this method, it is preferred to take out the press-formed article from the mold after cooling after press molding until the glass exhibits a viscosity of 10 dPa's or more. The optical member obtained by press molding is taken out from the press molding die and gradually cooled as needed. When the molded article is an optical article such as a lens, an optical film may be coated on the surface as needed. [Embodiment] The present invention will be further described below by way of examples. However, the invention is not limited to the form shown in the embodiment. Reconstituted optical glass Table 1 provides the glasses of Examples i to 18 and Comparative Examples i and 2

And, and into. Among them, a variety of var. @P., oxides, hydroxides, carbonates, and nitrates are used as starting materials for the different components of each of these 4 glasses 319107 28 1359121. Weigh the starting materials to vitrify, mix thoroughly, feed them into a platinum crucible, melt in an electric furnace at 1,200 to 1,30 (temperature range of TC, homogenize by stirring, clarify, and After preheating into a metal mold of appropriate temperature, the composition provided in Table 1 is produced. After cooling the cast glass to the glass transition temperature, it is directed to the annealing furnace where it is cooled directly to the chamber. Various optical glasses were thus obtained. * The following procedures were used to determine the glass transition temperature (Tg), relaxation temperature (Ts) and ratio of the optically broken glass of Example 14. The glass transition temperature (Tg), the sag temperature (Ts), and the a/phal/a ratio p/ja2 ratios are all obtained in a similar manner. Their values are provided in Table 2. 丨· Thermomechanical analysis A fixed weight of 1 gram was applied to the longitudinal axis of the cylindrical glass sample, which was sufficiently annealed and sized to a length of 20 mm and a diameter of 5 mm and at a fixed rate of 4 ° C/min. The glass sample was heated and repeatedly measured at 15 second intervals According to this, the measurement is performed at an interval of 1 ° C (/^L7MT = rc). The TMA curve shown in Fig. 1 is from the measurement result by the amount of elongation TMA of the sample. Plotted on the Y-axis (the vertical axis on the left side of the graph) and the plot is plotted on the χ_axis. The curve shown in Figure i is based on the temperature of the sample per 1 °c. The change in the elongation of the difference is plotted on the Y-axis (the vertical axis on the right side in Figure )) and the temperature is plotted on the X_ axis. That is, the Χ7Χ corresponds to the temperature difference per rc. The TMA difference of the value. Here, "the elongation of the sample is the elongation of the height of the cylindrical glass sample. The temperature difference is 1 ° C or less, and the solid value is 319107 29 1359121, as shown above. The narrator can obtain a measurement with sufficient accuracy when it is set to 丨. · 2· The γ7MAMA (the difference in elongation) reaches the maximum value from the DTMA curve obtained in 1. Temperature T1. 3. Based on the TMA curve, determined according to the standard of the 〇ptical-Glass Industry Ass〇ciati〇n The glass transition temperature Tg and the temperature at which TMA reaches a maximum value ts. 0^ T The T1 and TMA curves paid in 2 give the elongation of the sample at τ 1 _ 5 .c and T1+5 C: TMA (Tb 5) and TMA (T1+5) 5. The Tg and TMA curves obtained in 定3 determine the elongation of the sample at Tg-160 C and Tg-140 °C: TMA (Tg_16〇 And TMA (Tg-140) 6. Calculate the typical value of the average linear expansion coefficient in the temperature range from the glass transition temperature (Tg) to the sag temperature (Ts) as follows: 34/^1 (/γ) = {ΤΜΑ(τ1+5)_ΤΜΑ(τ卜5)}/sample length ♦ "5.0 (-5. 〇}. 7. Calculate the typical it alpha2 of the average linear expansion coefficient below Tg as follows: · ΜρΛ32(/γ) = {ΤΜΑ(τ§—14(rc)_TMA(Tg—16〇.〇}/sample length/ {140 C (-160 C) }. "Sample length" means that the sample is at 25 (the length of the '' is 20 mm.

8. Calculate the alphal/alphaZ scale from the values of the resulting alphal and alpha2.

The refractive index (nd), Abbe number (nud), and specific gravity of the optical glasses of Examples 1 to 18 and Comparative Examples J 319107 30 1359121 and 2 were measured in the following manner and are shown in Table 2. (1) Refractive index (nd) and Abbe's number (nud) The obtained optical glass was measured at a gradual cooling rate of 30 ° C / hour. (2) Specific gravity Calculated by the Archimedes method.

31 319107 1359121 [Table 1]

7π oggog O gg § gggggggggggo —1 ooogg 〇gg ο — ogg O ο 〇ο ψ O o —' § C3 Hj CO » T1»— sg csi sg CO g another··«— s CO f _ s cri a T ' - o CO sg 〇> g od g cx> S gs CO 3 o co S o* g CO g CO o CO w — g CO o 04 ir—* g CO T.— o CO » § CO ▼ one s oi g GO* CO s GO gygo « ο o LT> g < g inch 8 O' ggooggggg Ο ogg 〇gogg 3 § 〇> oo <=> o* c>〇> OO <r>G>c=>〇><=> o' C>C> 〇· o' g LT3 CVl €〇g LO o lo o LO s cri s CO g LO O LO o LO ο ixi gg LO g s寸· s to o 〇· S csi g 〇gg C=> cC oi 1— LO goo 〇g S ggggsggggg 0 gg <=>C>c> CD <=>G> o' 〇io* Cri c>c><=> o' ci <=> 〇· O' CD <r> S OO 〇> s OJ s cvi s oi g csi g cvi s csi sg csi sgsag 〇> g cri § CNJ ogo* s csi go* en g. CO CO 〇»' s T ss S » ss sub • 丨 · s — 1 sg Cft gs CO g CO g cvj g cvl ° 丨__ og CO § vp S <P CO g to g 甘o CO g CO sgs CO s CO s CO S esi o u> CO s LT? S LO μ s r -* g CO g 〇* s €vi ES g CO 8 C£> gogsog O gsssgsg CO* 兮CO· CO OO LO <〇LO CO inch o « 〇> od CO τ a T- , a cd 〇 > c? g 1 g « _ gg — sgggg arm · gt~ go' 3 c> gogdg Ο g 〇· g 〇* gc=> go _<SJ IXj> gg 〇gggggggogsg ο osg CNI g CO CO CNJ ▼ — 丨·— T αο co_ V t — CO sso S gs S ooo 〇sggs ο g § g a * g to CO ✓ lt» CO tri CO uS CO LO CO 艺 · ή c0 CO ss' CO eg s CNi LO 〇>IX> Cp CN σ> o Csj "T· CO 寸 ID CO 卜 CO ώ CM CM CO to CO 卜Q〇-T— ώ • o 2 ι2 ώ ώ ώ ώ ώ ώ CL E Q. 〇319107 32 1359121 [Table 2] <〇LT> %

Si

Si 5 § oo oo s s s

CO oo CO i co CO co

CO tr> CSJ CO 〇>〇>〇>〇> CN| 〇> CN| cva <〇 co CNi CNi tr> co oo oo 〇>

CO ir> CNI CNJ 〇> LO ir> o. Si i

[9S s

65S 6Z9 is called lil called TIT TIT liT lil OJ 3i inch s

OS s

61S s IOO8S is called nr 1ST "1ST IS" 1ΪΓ Nl lil lil HI Ίίί p/i

9SS ss

US

OCNIS

81S ss

COCOK ss oevllsl 59 95 Is.ts ssl 06SI SCOI9 05 ^.s ^.K ozlsl a -s pu 1.- 1--

In 1- 3S, l

SSI 1-- _9-l s scolz _ 浜699 i 1·- s§.l 93ΙΠ 1-11ΙΠ 0,1 ncolln xt>s6^oedto

9S

Is ore con 69 ·ε 5 zsrI 61." 5 5 15 0Ξ 06 _ss s s zre Lolrcol

rxLU CJ.X3 COX3 inch.X3 S.X3

toxLU

Orxluj 6.X3 COIXLUI ii l?l ΤΓ 1- Ιώι lI ιώι ώι ώι 130.IE00I1 t.xIXJI.duJOoI ools ΓΧΙ3 33 319107 1359121 The pre-forms used in the manufacture of press molding are made corresponding to Examples 1 to 18 The clarified and homogenized glass melts of Comparative Examples 1 and 2 were flowed out from a tube made of a platinum alloy at a fixed rate, and the tube was adjusted to a temperature at which the glass could flow stably without devitrification. The temperature within the range. The glass melt paste ball having the weight of the target preform is separated by a drop method or a drop-cut method. Then, the glass melt paste ball is received by receiving the mold, the mold has a gas blow hole at the bottom thereof, the gas can be blown through the gas blow hole, and the fine melt pressure is molded in the float of the glass melt paste ball. A preform used for molding. The breaking interval of the glass melt is adjusted and set to obtain a spherical glass preform having a diameter of 2 to 丨〇 mm and a spheroidal preform having a diameter of 5 to 25 mm. I made an optical element. The non-broken surface was read, and the preform obtained by the above method was subjected to precision press molding using a press shown in Fig. 2 to obtain an aspherical lens. Specifically, the pre-form 4 is placed between the lower mold 2 and the upper mold constituting the press molding mold, and the inside of the quartz tube 11 is reversely filled with a nitrogen atmosphere, and the heater 12 is turned on to heat. The inside of the quartz tube U. The inside of the press molding die was set to a temperature at which the molded glass exhibited a viscosity of 1 〇 8 to 1 〇 1 GdPa.s. While maintaining this temperature, the pressure bar 3 is lowered and pressed down onto the upper mold 1 to shrink the preform which has been placed in the dust-molding mold. The dust used in the compression was 8 MPa and the compression time was 30 seconds. In Figure 2♦, the 'sleeve mold 3, also called the drum mold, determines the relative configuration of the upper mold i ” lower loose 2, and performs the function of limiting the spread of the glass. A 319107 34 1359121 support rod 9 is used to withstand The pressure applied by the pressure bar 13. A press molding mold holder ίο is used to hold the press molding die. A thermocouple 14 is used to monitor the temperature of the lower mold 2. After compression, it is released in compression. The pressure used. The molded glass article obtained by pressure molding is gradually cooled to a temperature at which the glass exhibits a viscosity of 10 μPa·s or more while still being in contact with the lower mold 2 and the upper mold 1 . And then rapidly cooled to room temperature. Thereafter, the molded glass article was taken out from the press molding die to obtain an aspherical lens. When the glass of Examples 1 to 18 was used, in the precision press molding process Little damage was observed on the glass. In particular, for Examples 1 to 1 13, 14, and 16 to 18, there was 15 or less. For example, 1 "4 such as 2 ratio of the glass, no damage was observed. . In this case, in the glass precision press molding of Comparative Examples 1 and 2, damage to the glass was observed in h. As is clear from these results, all of the glass portions of Examples 丨 to 18 have desired optical properties and good formability, which can facilitate precision press molding using a press molding die without causing glass. damage. The present invention provides an optical glass having an optical constant suitable for precision press molding. From the optical glass of the present invention, a preform for precision press molding can be produced with high productivity. The present invention further provides an optical element composed of optical glass having high productivity. Although the present invention has been described in some detail in detail, it is possible that other types, and variations, permutations, and equivalents of the type shown may be read by those skilled in the art and in the study of the drawings. 319107 35 1359121 can use a variety of features of the various aspects of H have the purpose of using 2 'and without limiting the invention, . . . a soap street language. Therefore, the scope of any attached patent application is not limited to the description of the preferred version included in this " and should include both the true meaning and the scope (4) all such changes and discharges. = Having fully described the present invention, it will be apparent to those skilled in the art that: the inventive method can be carried out using a broad and equivalent range of conditions, with example parameters, without departing from the scope of the invention or any specific reference thereto. All patents and publications are hereby incorporated by reference in their entirety in their entirety in their entirety. Any public quotes are :: pre-exposures and should not be construed as recognizing such disclosures as prior art. = 2 inventions are not qualified. #Previous creations are disclosed than such [simplified illustrations] x

In the Gemingtai IS, the present invention will be described by way of non-limiting specific examples shown in the drawings, wherein: FIG. 1 is a TMA curve and an mmMA curve of the glass of Example 1. FIG. 2 is a precision press molding die. schematic diagram. Main component symbol description] 2 4 10 12 I Upper mold 3 Sleeve mold 9 Support rod II Quartz tube Lower mold Preform Pressing mold holder Heater 319107 36 1359121 Thermocouple 13 Pressure rod 14

% 37 319107

Claims (1)

1359121 Patent Application No.: PCT Patent Application No. 96109669, the entire disclosure of which is incorporated herein by reference. The composition is such that the refractive index (nd) of the glass is greater than or equal to 165 and the Abbe number (yd) greater than or equal to 50, and the ratio of a as an index is less than 17, wherein the transition temperature (Tg) from glass to sagging The temperature of the temperature (Ts) within the temperature range 'expresses the difference in temperature d relative to the temperature difference d where j T represents a fixed value of 1 C or less) is expressed as Τ1 and will be from Τ1-5: The average linear expansion coefficient in the range of T1 + 5 ° C is expressed, and will be expressed from the glass transition temperature (Tg) _160 ° C to the glass transition temperature (Tg) _ 14 (average linear expansion coefficient in the range of rc) And (2) manufacturing a preform for precision press molding by using the glass having the composition thus determined. The manufacture of a pre-formed product for precision press molding as described in claim 1 Method, wherein A preform for precision press molding using glass, and the glass has a composition having a measured value of less than 17. The precision described in claim 1 or 2 A method for producing a preform for press molding, wherein the refractive index is in the range of 丨 to 1.70, and the composition includes Si〇2, Βζ〇3, La2〇3, and Gd2〇3 as essential components, Si (The total content of h and B2〇3 is in the range of 5〇 to 72mol%, and the ratio of si〇2 content to (iv) content (Si〇2/B2〇3) is patented by Moer 319107 Rev. 38 No. 96109669 On August 12, 100, the corrected replacement ratio is expressed as more than 〇·5 and below 0.90, and the content of 1^〇3 is in the range of 4.87 to 10% by mole. The content of Gd2〇3 is 3.30 to 8 mol%. 4. The method of manufacturing a preform for precision press molding as described in claim 1 or 2, wherein the aforementioned refractive index exceeds 1.70, and the aforementioned composition contains si 〇2. B2O3, La2〇3 and Gd2〇3 as essential components 'Si〇2 content is 11 to 18 mol% Range, La2〇3 content in the range of 5 to 15 mol% 'Gd2〇3 content in the range of 1 to 12 mol% 'the total content of Si〇2 and B2〇3 is in the range of 50 to 72 mol%' The ratio of the Si〇2 content to the 匕〇3 content (SiOV B2〇3) is expressed in the range of 0.1 to 0.90 in terms of molar ratio. 5. The optical glass is used for precision press molding and An optical glass having a refractive index (nd) in the range of 1.65 to 1.70 and an Abbe number (wd) of 50 or more, wherein the temperature range from the glass transition temperature (Tg) to the sag temperature (TS) Inside, the temperature exhibiting a difference in maximum glass elongation relative to the temperature difference Z1T (here, a fixed value of rc or less) is expressed as T1 'will range from T1 -5 ° C to T1 + 5 ° C The average linear expansion coefficient within is expressed by α 1 and the average linear expansion coefficient in the range from the glass transition temperature (Tg ) -16 0 ° C to the glass transition temperature (Tg) - 140 ° C is represented by α 2 , Its (α1/α2) ratio is less than 17, and contains Si〇2, Β2Ο3, La2〇3, and Gd2〇3 as essential components, and the total content of si〇2 and B2〇3 is 50 to 72 m. % range, si 〇2 content 39 319107 Revised version 96109669 Patent application August 12, 100 Revision ratio of replacement page to B2〇3 content (Si〇2/B2〇3) expressed in molar ratio Above 0.5 and below 〇·9〇, the content of La2〇3 is in the range of 4.87 to 10 mol% 'Gd2 (h content is in the range of 3.30 to 8 mol%). An optical glass used for precision pressure molding of an optical glass having a refractive index (nd) exceeding 1.70 and an Abbe number (yd) of 50 or more, wherein the glass transition temperature (Tg) to the sag temperature ( In the temperature range of Ts), the temperature exhibiting a difference in maximum glass elongation relative to the temperature difference 4 T (where JT represents a fixed value of 1 °c or less) is expressed as T1 and will be from Tl-5. The average linear expansion coefficient in the range of °c to Tl + 5°c is expressed by α 1 and will range from the glass transition temperature (Tg)_16〇t>c to the glass transition temperature (Tg) -14〇°c. The average linear expansion coefficient is represented by α 2 , the ratio of (α 1 / α 2 ) is less than 17, and contains Si〇2, b2〇3, La2〇3, and Gd2〇3 as essential components, and the Si〇2 content is 11 To the range of 18% by mole, the La"3 content is in the range of 5 to 15 mol%, the GdzO3 content is in the range of 1 to 12 mol%, and the total content of Si〇2 and 匕〇3 is 50 to 72 mol. In the range of %, the ratio of Si〇2 content to B2〇3 content (Si〇2/B2〇3) is in the range of Mo莫90.仕.1 Main 2 Preform for precision press molding, which is composed of the optical glass described in the scope of claim or item 6. The optical element is a member of the optical glass described in claim 5 or 6. And a method for learning a component, which comprises heating a preform of a patent application scope; and using a precision press molding die to heat the 319107 revision 40. Patent application No. 96109669, revised August 10, pp. 1359121 The preform is subjected to a precision press molding method. 10. A method of manufacturing an optical component, comprising: heating a preform produced by the manufacturing method according to any one of claims 1 to 4; and using a precision press molding die The heated preform is subjected to a precision press molding method. 41 319107 revision