TW202136820A - Glass material for use in molding - Google Patents

Abstract

To provide a glass material that is to be used in molding and that has excellent stability when being reheated. A glass material to be used in molding, wherein the maximum value [alpha]max of the coefficient of linear expansion of the glass material and the total content [SiO2+ZrO2] of SiO2 and ZrO2 expressed as wt% satisfy formula (1). (1): [alpha]max*[SiO2+ZrO2] ≤ 27900.

Description

Glass materials for molding

The present invention relates to glass materials for molding.

Optical glass not only has specific optical constants such as refractive index and Abbe number, but also has the characteristics of high light transmittance and homogeneity of optical properties. It is different from conventional silicate-based glass such as window glass and can glass.

In recent years, in response to the high-definition of video equipment, the requirements for high-performance cameras have also increased, and the requirements for low-profile optical components themselves have also increased. Therefore, an optical glass with a high refractive index and excellent stability is expected.

Here, as for the manufacturing method of the optical glass, for example, a reheat press method in which glass is reheated and molded, a round rod molding method, an extrusion molding method, and the like. For example, in these production methods, for example, a large amount of _{silicate-based optical glass with components that improve optical properties such as Nb 2} O ₅ , TiO ₂ , or La ₂ O _{3 is introduced,} and the stability of the glass is likely to decrease, especially when reheating. The problem of crystallization.

It is known that an inorganic compound melt that is easy to crystallize can be vitrified by quenching. Therefore, the inorganic glass that is the object of the present invention is to cool the molten inorganic compound at a faster rate than the crystallization progress rate, so that the disordered atomic arrangement in the molten state can be maintained/frozen even at room temperature.

However, at least optical glass that does not absorb visible light has a low thermal conductivity even in a molten state. Therefore, the cooling rate of the entire glass decreases as the thickness of the glass increases, and there is a limit to the quenching effect. For example, as shown in Non-Patent Document 1, if a glass melt with a thickness of 0.5 mm is press-formed with a metal plate, even if ^{a cooling rate of 10 2} to 10 ³ ℃/sec can be obtained, the glass melt with a thickness of 5 mm is performed with a metal plate. The cooling rate during press forming still stays at 10-20°C/sec. For this reason, the glass obtained by quenching is like the "sheet" shown in Non-Patent Document 2.

Furthermore, it has a relatively large thickness of about 10 mm for the glass used for molding into an optical element, and continuous melting is used to produce glass with a thickness of 30 mm or 40 mm. However, if there are crystals in the glass, it will cause light scattering, so such glass cannot be used as an optical element. It is assumed that even if the surface of the glass with such a thickness is quenched to obtain glass, the inside of the glass is not sufficiently quenched, which may cause crystals to appear inside the glass. In addition, if the cooling conditions are excessively strengthened to avoid such crystallization inside the glass, the surface of the glass will solidify earlier than the inside of the glass, and as a result, problems such as cracks or glass breakage will occur.

According to this, when the glass with a certain thickness is manufactured, the use of ordinary quenching operation to vitrify without crystallization is limited to the vicinity of the surface. In addition, even if the glass that has crystallized inside is reheated, the tendency to crystallize does not disappear, and there is a high possibility that the glass will crystallize again during molding. Therefore, the glass material obtained in this way cannot obtain a desired shape even if it is heated and softened, and therefore cannot be used as an optical glass used in general industries.

On the other hand, Patent Document 1 discloses a prior art that proposes a cooling condition different from ordinary cooling conditions for optical glass. That is, it is disclosed that for a _{silicate glass containing a large amount of TiO 2} , the molten glass is cooled to room temperature, and then annealed at a temperature lower than the glass transition temperature Tg to remove strain, thereby obtaining energy when reheated. A glass material that inhibits the formation of crystals.

However, the optical glass obtained from the glass material of Patent Document 1 cannot meet the requirements of recent years such as low light transmittance in the short wavelength region of visible light (especially blue), partial dispersion ratio Pg, and large F value. Design requirements. [Advanced Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2003-192384 [Non-Patent Literature]

[Non-Patent Document 1] Sakuhashio "Glass Amorphous Science" (1983) p.23 [Non-Patent Document 2] New Glass Forum (Company) "New Glass Basic Lecture" (1983) p.2-6

[The problem to be solved by the invention]

The present invention was completed in view of such circumstances, and its object is to provide a molding glass material having excellent stability during reheating. [Means to solve the problem]

The gist of the present invention is as follows. [1] A glass material for molding, which is the maximum linear expansion coefficient α _max , and the total content _{of SiO 2} and ZrO ₂ expressed by mass% _{[SiO 2} +ZrO ₂ ], and satisfies the following formula (1): α _max ×[ SiO ₂ +ZrO ₂ ]≦27900 ・・・(1)

[2] A glass material for molding, which is the maximum linear expansion coefficient α _max , the average linear expansion coefficient α _{100-300 at 100-300} °C, and the total content _{of SiO 2} and ZrO ₂ expressed by mass% _{[SiO 2} +ZrO ₂ ], satisfies the following formula (4): α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦264 ・・・(4)

[3] A glass material for molding, the maximum linear expansion coefficient α _{max is} smaller than that after the glass material for molding is soaked at the glass transition temperature Tg, then cooled at -30°C/hr for 4 hours, and then The maximum linear expansion coefficient α _max (Tg) of the glass material obtained by cooling.

[4] The glass material for molding as described in [1] to [3], when a sample of 11mm×11mm×10.5mm is heat-treated for 5 minutes at a temperature 200°C higher than the glass transition temperature Tg, the glass per 1g The number density of crystals D is less than 10/g.

[5] The glass material for molding as described in [1] to [4], wherein the TiO ₂ content [TiO ₂ ] and the Nb ₂ O ₅ content [Nb ₂ O ₅ ] expressed in mass% satisfy the following formula (7): {5×[TiO ₂ ]}/{3×[Nb ₂ O ₅ ]}≦3 ・・・(7)

_{[6] The glass material for molding as described in [1] to [5], wherein the wavelength λτ 80} at which the internal transmittance of glass with a thickness of 10 mm is 80% in the wavelength range of 280 to 700 nm is 395 nm or less.

[7] The glass material for molding as described in [1] to [6], wherein the Abbe number νd and the partial dispersion ratio Pg, F system satisfy the following formula (8): Pg,F≦-0.00286×νd+0.68700 ・・・(8)

[8] An optical glass formed from the glass material for molding as described in [1] to [7] above. [Effects of the invention]

According to the present invention, it is possible to provide a molding glass material having excellent stability during reheating.

In the present invention and this specification, the glass composition is expressed on the basis of oxides unless otherwise stated. The so-called "oxide-based glass composition" here refers to the glass composition that is completely decomposed when the glass material is melted, and the glass composition is converted according to the oxide form in the glass. The expression of each glass component follows the customary SiO ₂ , TiO ₂ etc. Record. The content and total content of the glass components are based on quality unless otherwise stated. "%" means "mass%". In addition, "glass materials for molding" may also be referred to simply as "glass" or "glass materials".

The content of the glass component can be quantified in accordance with known methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS) and other methods. In addition, in this specification and the present invention, the "content of a constituent component is 0%" means that the constituent component is not substantially contained, and it is allowed to contain the component depending on the degree of unavoidable impurities.

Hereinafter, the glass material for molding of the present invention will be described in accordance with the first embodiment, the second embodiment, and the third embodiment, respectively. In addition, the glass characteristics of the second and third embodiments are the same as the glass characteristics of the first embodiment. In addition, the functions and effects of the respective glass components in the second and third embodiments are the same as the functions and effects of the respective glass components in the first embodiment. Therefore, in the second and third embodiments, descriptions and overlapping matters related to the first embodiment are appropriately omitted.

First Embodiment The molding glass material of the first embodiment has the maximum linear expansion coefficient α _max and the total content _{of SiO 2} and ZrO ₂ expressed by mass% _{[SiO 2} +ZrO ₂ ], satisfying the following formula (1): α _max ×[SiO ₂ +ZrO ₂ ]≦27900 ・・・(1)

In the glass material for molding of the first embodiment, the maximum linear expansion coefficient α _max and the total content _{of SiO 2} and ZrO ₂ expressed by mass% _{[SiO 2} +ZrO ₂ ] satisfy the following formula (1), preferably It satisfies the following formula (2), and more preferably satisfies the following formula (3). By satisfying the following formula, a molding glass material with excellent stability during reheating can be obtained. α _max ×[SiO ₂ +ZrO ₂ ]≦27900 ・・・(1) α _max ×[SiO ₂ +ZrO ₂ ]≦27500 ・・・(2) α _max ×[SiO ₂ +ZrO ₂ ]≦27000 ・・・(3)

The maximum linear expansion coefficient α _max is in the manufacturing step of the glass material described later, and can be controlled by adjusting the conditions for cooling the molten glass.

The method of measuring the coefficient of linear expansion is measured in accordance with the regulations of JOGIS08 of the Japan Society of Engineering Industries. The sample system is a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. In a state where a load of 98 mN is applied to the sample, the sample is heated at a constant rate of 4°C per minute, and the temperature and sample elongation are measured every 1 second. Because the maximum linear expansion coefficient α _max is the maximum linear expansion coefficient between room temperature and the yield point temperature (the temperature at which the sample drops and the apparent extension stops), so as long as the temperature rises per unit, the sample extension becomes The coefficient of linear expansion at the maximum temperature is sufficient. The maximum value of linear expansion coefficient α _MAX can also be the maximum value obtained by moving average processing of linear expansion coefficients at 31 measurement locations. _{In addition, the average linear expansion coefficient α 100-300} described later is the average value of the linear expansion coefficient at 100 to 300°C.

In addition, in this specification, the maximum linear expansion coefficient α _MAX and the average linear expansion coefficient α _{100-300 are} based on JOGIS08 regulations and ^{expressed in units of 10 -7} ℃ ^-1 to the first place of the integer. That is, the maximum linear expansion coefficient α _MAX and the average linear expansion coefficient α _100-300 are expressed in integers in units of [10 ^-7 ·℃ ^{-1 ].} Furthermore, in this specification, the average linear expansion coefficient α is ^{expressed in the unit of [℃ -1} ], but even if the unit is [K ^-1 ], it is still the same as the average linear expansion coefficient α.

With regard to the glass material for molding of this embodiment, the characteristics and glass composition other than the above are shown as non-limiting examples below.

The glass material for molding of the first embodiment has the maximum linear expansion coefficient α _max , the average linear expansion coefficient α _100-300 at 100 to 300°C, and the total content _{of SiO 2} and ZrO ₂ expressed in mass% _{[SiO 2} +ZrO ₂ ], the preferred system satisfies the following formula (4), the more preferred system satisfies the following formula (5), and the particularly preferred system satisfies the following formula (5). In order to obtain a glass material for molding with excellent stability during reheating, it is preferable to satisfy the following formula. α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦264 ・・・(4) α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦260 ・・・(5) α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦255 ・・・(6)

The maximum linear expansion coefficient α _max and the average linear expansion coefficient α _100-300 are controlled by adjusting the conditions for cooling the molten glass in the manufacturing steps of the glass material described later.

For the glass material for molding of the first embodiment, the maximum linear expansion coefficient α _{max is} preferably smaller than that after the glass material for molding is soaked according to the glass transition temperature Tg, and then performed at -30°C/hr for 4 hours The maximum value of the linear expansion coefficient α _max (Tg) of the glass material obtained after cooling and then cooling. However, the maximum linear expansion coefficient α _max may be only slightly larger than the above-mentioned maximum linear expansion coefficient α _max (Tg). Therefore, if the difference between α _max and α _max (Tg) [α _max (Tg)-α _max ] is ^{expressed in the unit of 10 -7} ·℃ ^-1 to the first digit of the integer, it is preferably -9 or more, more preferably The order is in sequence -4 or more, 0 or more, 5 or more, 10 or more, 20 or more, 40 or more, 60 or more, 80 or more, 100 or more, 120 or more, 140 or more, 160 or more, 180 or more, 200 or more, 250 or more, Above 300, above 350, above 400. Although the upper limit of the difference is not particularly limited, it is usually α _max (Tg), preferably α _max (Tg)-100.

The maximum linear expansion coefficient α _max (Tg) is the maximum linear expansion coefficient of the glass obtained by maintaining the glass material for molding according to the glass transition temperature Tg and then cooling it for 4 hours at -30℃/hr. . In addition, the molding glass material of the first embodiment has the maximum linear expansion coefficient α _max , but does not have the maximum linear expansion coefficient α _max (Tg). As described later, a first embodiment of the molding glass material, since by having a low glass transition temperature Tg to maintain the temperature obtained, which has a smaller α _max to α _max (Tg) of.

When performing soaking in accordance with the glass transition temperature Tg, since the glass material for molding is heated to a temperature higher than Tg, the temperature can also be lowered to the same temperature state as Tg. Alternatively, the glass material for molding may be slowly heated to the same temperature as Tg.

FIG. 1 shows an example of the glass material for molding according to this embodiment, and a glass temperature chart in the manufacturing process. The glass material for molding of this embodiment is described later, and in step 2, the temperature is maintained at a temperature lower than the glass transition temperature Tg. Here, the maximum linear expansion coefficient α _max (Tg) is the comparative example (Tg1) in FIG. 1, and the maximum linear expansion coefficient of the glass is obtained by maintaining the glass transition temperature Tg in step 2. Alternatively, the maximum linear expansion coefficient α _max (Tg) can also be the comparative example (Tg2) in Figure 1. After heating the glass material for molding from room temperature, the glass material is heated at the same temperature as the Tg. After cooling, the maximum linear expansion coefficient of the glass is obtained.

When the glass material for molding is heated to a temperature higher than the glass transition temperature Tg and then cooled, the lower limit of the time required for soaking according to the glass transition temperature Tg varies according to the size of the sample, and the glass surface temperature becomes Tg After about 30 minutes, it can also be 1 hour, 2 hours, or 4 hours. The upper limit is not particularly limited, and is usually within 24 hours, preferably within 12 hours. In addition, the soaking time after the inside of the glass reaches the Tg temperature is preferably about 10 minutes.

When the glass material for molding is subjected to soaking, for example, even if the glass surface temperature becomes the glass transition point Tg, it is not limited to the internal temperature becoming Tg. Here, the determination of whether the soaking is sufficient can be known from the specific gravity. The glass obtained after being sufficiently uniformized by the glass transition temperature Tg and then cooled down, the specific gravity will hardly change even if the holding time of the uniformized state by Tg is elongated. On the other hand, before the soaking is performed according to the glass transition temperature Tg, for example, the glass obtained by cooling before the glass transition temperature Tg is reached, and the glass obtained by cooling the glass after the inside of the glass is sufficiently soaked according to Tg , There will be a difference in specific gravity.

Therefore, for example, according to the soaking method of the glass transition temperature Tg, the glass material for molding is heated in the furnace and maintained for a holding time t ₁ (hr) and then cooled to obtain the specific gravity d(t ₁ ) of the glass. Internal heating and maintaining the holding time t ₁ +K(hr) and then cooling to obtain the _{absolute value of the change in the specific gravity d(t 1} +K) of the _{glass [d(t 1} )-d(t ₁ +K)], which is more The best system is less than 0.002. Here, the lower limit of the K value is preferably 4, more preferably 8, and particularly preferably 12.

When the above-mentioned variation is satisfied, it can be judged that the soaking of the glass heated _{according to the holding time t 1 is sufficient.} In this case, the time required to perform soaking according to the glass transition temperature Tg is preferably t ₁ or more.

The method of cooling the glass homogenized according to the glass transition temperature Tg is carried out before cooling for 4 hours at a temperature drop rate of -30°C/hr after soaking, and the rest is not particularly limited. For example, a gradual cooling furnace that can be controlled by a temperature program can be used. In addition, even if the glass strain point is not lowered even if the glass is cooled from the holding temperature Tg at a cooling rate of -30°C/hr for 4 hours, it can also be performed from the holding temperature Tg at a cooling rate of -30°C/hr for 5 hours to 6 hours of cooling.

The heating temperature during reheating is usually the temperature at which the glass will soften and deform. Specifically, the heating temperature is a temperature that is about 50°C higher than the glass transition temperature Tg in a lower case, and a temperature that is about 200 to 300°C higher than the glass transition temperature Tg in a higher case. When the heating temperature during reheating is low, that is, when heating is performed at a temperature that is about 50°C higher than the glass transition temperature Tg, the stability of the glass can be easily ensured, and the occurrence of crystallization and devitrification can be suppressed.

However, if the heating temperature during reheating is low, higher pressure must be applied during molding. As a result, the molded glass product (for example, lens, lens blank, round rod, extrusion molded product, etc.) has a high possibility of cracking and glass breakage. Therefore, the low heating temperature during reheating is likely to cause a decrease in production yield, and the shape of the glass molded product that can be molded is also easily restricted.

On the other hand, when the heating temperature during reheating is high, that is, when heating is performed at a temperature of about 200 to 300°C higher than the glass transition temperature Tg, it can be deformed in a shorter time and the shape of the molded product can also be improved. Degree of freedom, but it is not easy to ensure the stability of the glass, easy to crystallize, and easy to devitrify. From these phenomena, the glass with the composition of the present invention is likely to precipitate crystals if the molding temperature is increased. In order to avoid the precipitation of crystals, the molding temperature must be set lower than that of conventional glass, resulting in cracks and fractures. The possibility of poor deformation is increased.

For the glass material for molding of the first embodiment, when a sample of 11mm×11mm×10.5mm is heat-treated for 5 minutes at a temperature 200°C higher than the glass transition temperature Tg, the number density D of crystals per 1g of the glass is preferably less than 10 Units/g, the upper limit is in order of 9 units/g, 8 units/g, 7 units/g, 6 units/g, 5 units/g, 4 units/g, 3 units/g, 2 units/g , 1/g. The best number of crystals is 0/g.

The number of crystals at the above-mentioned number density D is calculated based on the number of bright spots of the crystals confirmed by an optical microscope (100 times).

The above-mentioned number density D is calculated in the following order.

[Production of sample] First, observe with an optical microscope (100 times) to confirm that there are no identifiable foreign objects and crystals inside the glass. Then, the glass was cut and cutting was performed to obtain a cubic sample of approximately 11 mm×11 mm×10.5 mm. The surface of this sample is all sanded with the use of No. ♯80~400 stone stone.

[Soaking of heat treatment furnace] Set a temperature 200°C higher than the glass transition temperature Tg, perform soaking for 15 minutes or more after the furnace temperature reaches Tg+200°C, and put it into a heat treatment furnace with an internal space volume of about 25cm×about 10cm×about 10cm for heating.

At this time, the temperature controller of the heat treatment furnace is installed at the approximate center of the internal space. During the heat treatment of the glass sample, the glass sample is installed at a position within 3 cm from the sensor portion of the temperature controller.

[Preheating of receiving dish] A ceramic plate made of cubic hexahedral alumina with a size of about 10.5 cm×about 3 cm×about 1 cm was set as a receiving dish. Coat the front end of the receiving dish with an anti-welding agent such as powdered alumina, or a solid lubricant such as BN, 0.01 to 0.3 g, preferably 0.5 g to 0.15 g, more preferably 0.1 g, and place a glass sample on it. Into the heat treatment furnace for heating. The receiving vessel is placed in a heat treatment furnace for preheating for more than 15 minutes before the test.

[Heat Treatment of Glass Samples] The receiving vessel is taken out of the heat treatment furnace just before the glass sample is put into it, and the glass sample is immediately placed on the receiving vessel where the anti-welding agent or solid lubricant is coated, and then the glass sample is returned to the furnace together with the receiving vessel The original location within. The time until the receiving vessel is taken out until it returns to its original position is preferably within 10 seconds, more preferably within 8 seconds, and particularly preferably within 6 seconds in order to prevent the temperature of the receiving vessel from decreasing. After 5 minutes from the introduction of the glass sample, the glass was taken out from each receiving vessel, and after the glass sample was taken out from the receiving vessel, cooling was performed at a cooling rate that would not cause cracks. At this time, in order not to affect the stability of the glass and to cool efficiently, it is best to roll the glass sample out of the furnace immediately (after about 3±1 seconds) in the ceramic fiber, etc. The sample is also covered with ceramic fibers to the degree of no compression, and then cooled to room temperature. The end of the cooled glass sample was optically polished, and the inside of the glass sample was observed with an optical microscope (100 times). During optical polishing, the softened glass sample preferably retains more than 80%, more preferably more than 85% of the observed volume. The number of crystals (bright spots) inside the glass sample was counted, and the weight of the sample after optical polishing was measured and converted into the number per 1 g.

The first embodiment of the molding glass material, by mass% TiO ₂ content represented by [TiO _2] and Nb ₂ O ₅ content [Nb ₂ O _5], based preferably satisfies the following formula (7): {5 × [ TiO ₂ ]}/{3×[Nb ₂ O ₅ ]}≦3 ・・・(7)

The upper limit of {5×[TiO ₂ ]}/{3×[Nb ₂ O ₅ ]} mentioned above is to further reduce Pg, F and achieve the purpose of glass stability and/or high refractive index, preferably 2, A more preferable sequence is 1.25, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5. On the other hand, from the viewpoint of reducing Pg, F and increasing the transmittance of the blue region λτ80, _{the upper limit of 5×[TiO 2} ]}/{3×[Nb ₂ O ₅ ]} is preferably 0.4. A more preferable order is 0.3, 0.2, 0.1. The above 5×[TiO ₂ ]}/{3×[Nb ₂ O ₅ ]} can also be set to 0.0.

The above {5×[TiO ₂ ]}/{3×[Nb ₂ O ₅ ]} indicates the ratio of Ti ions to Nb ions in the glass material for molding. If there are too many Ti ions, the partial dispersion ratio of Pg and F may increase. In addition, there is a concern that fine crystal nuclei may be generated when the molten glass is cooled. Therefore, depending on the subsequent molding conditions, the growth of crystals may result in degradation of optical properties, which may hinder glass production. Therefore, in order to suppress the increase in the partial dispersion ratio Pg, F and suppress the crystallization of the glass, it is preferable to satisfy the above formula.

In the glass material for molding of the first embodiment, the partial dispersion ratio Pg, F preferably satisfies the following formula (8), more preferably satisfies the following formula (9), particularly preferably satisfies the following formula (10), and the best system The following equation (11) is satisfied, and the best system meets the following equation (12). The partial dispersion ratio Pg, F satisfies the following formula to provide an optical glass suitable for chromatic aberration correction. Pg,F≦-0.00286×νd+0.68700 ・・・(8) Pg,F≦-0.00286×νd+0.68600 ・・・(9) Pg,F≦-0.00286×νd+0.68500 ・・・(10) Pg,F≦-0.00286×νd+0.68400 ・・・(11) Pg,F≦-0.00286×νd+0.68300 ・・・(12)

The partial dispersion ratio Pg, F uses the respective refractive indexes ng, nF, and nC of the g-line, F-line, and C-line, and is expressed by the following formula (13): Pg,F=(ng-nF)/(nF-nC) ・・・(13)

The partial dispersion ratio Pg, F is adjusted by adjusting the mass ratio [(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)/(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )], mass ratio [(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )], mass ratio [(SiO ₂ +P ₂ O ₅ + B ₂ O ₃ )/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )], mass ratio [ZrO ₂ /(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )], Mass ratio [P ₂ O ₅ /(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )], mass ratio [Nb ₂ O ₅ /(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] Can be controlled.

Furthermore, ΔPg, F is the deviation of Pg, F from the normal, which can be obtained according to formula (14): ΔPg,F=Pg,F-(0.6483-0.001802×νd) ・・・(14)

The glass material system for molding of the first embodiment can be a high-dispersion glass with a small partial dispersion ratio Pg and f. In high-dispersion glass, by reducing the Pg and f values, it is easy to suppress the focus distance shift near the g-line when performing decolorization (focus distance adjustment) focusing on the F line and C line, that is, it is easy to suppress the short wavelength range. Chromatic aberration occurs. In addition, when the image captured by the camera is zoomed in, the contrast can be easily improved. In addition, when viewing digital images electronically, the edge of the object can be easily viewed, and the computational load of the image engine can be expected to be suppressed.

The glass material for molding of this embodiment may have glass composition A, glass composition B, or glass composition C described in detail below.

(Glass composition A) Hereinafter, regarding the case where the glass material for molding of the present embodiment has the glass composition A, the content and ratio of the glass components, and the glass characteristics will be described.

In the glass material for molding of the present embodiment, when the glass composition is A, it is preferably a silicate-based glass in which the _{glass network forming component mainly contains SiO 2.} The lower limit of the content of SiO ₂ is preferably 0%, and more preferably 6%, 11%, 16%, and the larger the value, the better. Especially when the thermal stability is more important than the refractive index of the glass, _{the lower limit of the SiO 2} content is preferably 21%, and it can also be set to 24%, 26%, or 28%. In addition, _{the upper limit of the SiO 2} content is preferably 40%, and the order is more preferably 38%, 35%, 33%. The smaller the value, the better, especially when the refractive index is more important than the stability of glass. The upper limit of the SiO ₂ content is preferably 30%, and can also be set to 28%, 26%, or 25%.

SiO ₂ is a network forming component of glass in the glass composition A, and has the functions of improving the thermal stability, chemical durability and weather resistance of the glass, increasing the viscosity of the molten glass, and making the molten glass easy to form. It also has the effect of improving the thermal stability during reheating and reducing the crystal number density D. On the other hand, if the _{content of SiO 2 is} too high, the devitrification resistance of the glass tends to decrease, leading to an increase in Pg and F. Therefore, the _{content of SiO 2 is} preferably within the above range.

When the glass material for molding of this embodiment is glass composition A, it is preferable to contain P ₂ O ₅ . The lower limit of the content of P ₂ O ₅ is preferably 0%, and the more preferable order is 0.2%, 0.4%, and 0.6%. In addition, _{the upper limit of the content of P 2} O ₅ is preferably 10%, and the more preferable order is 8%, 7%, 6%, 5%, 4%.

In the glass composition A, when _{the lower limit of the content of P 2} O ₅ satisfies the above, the thermal stability during reheating is also improved, and the number density D of crystals is reduced. In addition, since _{the upper limit of the P 2} O ₅ content satisfies the above, the increase in the partial dispersion ratios Pg and F can be suppressed, and the stability during reheating can be maintained.

In the glass material for molding of the present embodiment, in the case of the glass composition A, _{the upper limit of the B 2} O ₃ content is preferably 20%, and the more preferable order is 14%, 9%, and 4%. The _{content of B 2} O ₃ may also be 0%.

B ₂ O ₃ is a network forming component of glass in the glass composition A, and has the effect of improving the melting property of the glass and improving the thermal stability. On the other hand, if the _{content of B 2} O _{3 is} too large, the volatilization amount of the glass component may increase when the glass is melted, and it also tends to hinder high dispersion and reduce the devitrification resistance. In addition, compared with the case of substituting the same amount of SiO ₂ , there is a concern that the viscosity of the glass will be lowered. However, if it is introduced excessively, the thermal stability during reheating may also decrease. Therefore, the _{content of B 2} O _{3 is} preferably within the above range.

In the molding glass material of the present embodiment, in the case of the glass composition A, _{the upper limit of the Al 2} O ₃ content is preferably 20%, and the more preferable order is 9%, 4%, 2%, and 1%. The _{lower limit of the Al 2} O ₃ content is preferably 0%, and the more preferable order is 0.02%, 0.04%, 0.08%, 0.12%, 0.14%, 0.16%, 0.2%, 0.3%. The _{content of Al 2} O ₃ may also be 0%.

In the glass composition A, Al ₂ O ₃ is a glass component that has the effect of improving the chemical durability and weather resistance of the glass, and can be considered as a network forming component. On the other hand, if the Al ₂ O ₃ content is too large, the devitrification resistance of the glass decreases. In addition, as the glass transition temperature Tg increases, when the molten glass is cooled, problems such as a decrease in thermal stability are more likely to occur. From the viewpoint of avoiding such problems, the _{content of Al 2} O _{3 is} preferably within the above-mentioned range. In addition, when the glass melt is melted and transported, a refractory brick container and/or ladle may be used, and the Al ₂ O ₃ content may be set to 0.02% or more.

In the glass material for molding of this embodiment, in the case of glass composition A, the lower limit of the total content of _{SiO 2} and P ₂ O _{5 [SiO 2} +P ₂ O ₅ ] is preferably 5%, and more preferably in order 11%, 16%, 21%. Especially when stability is important, the lower limit of the total content is preferably 24%, and can also be set to 27% or 30%. In addition, the upper limit of the total content is preferably 40%, and the more preferable order is 38%, 36%, 34%, 33%.

In the glass composition A, when the lower limit of the total content of _{SiO 2} and P ₂ O _{5 [SiO 2} +P ₂ O ₅ ] satisfies the above, the thermal stability during reheating can be improved and the number density D of crystals can be reduced. In addition, when the upper limit of the total content satisfies the above, it is possible to suppress the decrease in refractive index and increase the partial dispersion ratio Pg and F, and the thermal stability of the glass can be maintained.

In the glass material for molding of this embodiment, in the case of glass composition A, the lower limit of the total content of _{SiO 2} , P ₂ O ₅ and B ₂ O _{3 [SiO 2} +P ₂ O ₅ +B ₂ O _{3] is preferable} The best order is 10%, 15%, 18%, 21%, 22%, 23%. In addition, the upper limit of the total content is preferably 50%, and a more preferable order is 45%, 40%, 37%, 35%, 34%, 33%. Especially when the refractive index is important, the upper limit of the total content is preferably 30%, and may be 28%, 26%, or 25%.

In the glass composition A, from the viewpoint of maintaining stability during reheating, the total content [SiO ₂ +P ₂ O ₅ +B ₂ O ₃ ] is preferably within the above-mentioned range.

In the glass material for molding of this embodiment, in the case of glass composition A, the upper limit of the mass ratio [B ₂ O ₃ /SiO _{2 ] of the content of B 2} O _{3 to the} content of SiO _{2 is} preferably 0.80, and more preferably, the order follows Sequence system 0.70, 0.60, 0.50, 0.40, 0.30, 0.20, 0.10, 0.05, 0.03. In addition, the lower limit of the mass ratio is preferably 0, and the more preferable order is 0.005, 0.01, 0.015, and 0.02 in this order. The mass ratio may also be zero.

In the glass composition A, from the viewpoint of suppressing an increase in the specific gravity of the glass and suppressing an increase in the coloring of the glass, the mass ratio [B ₂ O ₃ /SiO ₂ ] is preferably within the above-mentioned range.

Molding glass material of the present embodiment, when the glass composition A, P ₂ O ₅ content relative to the mass of SiO ₂ and P ₂ O ₅ total content ratio of _{[P 2 O 5 / (SiO} 2 + P 2 O 5 )] The lower limit is preferably 0.00, and the more preferred order is 0.006, 0.011, 0.016, 0.021. In addition, the upper limit of the mass ratio is preferably 0.20, and the more preferable order is 0.18, 0.16, 0.14, 0.12, 0.11.

In the glass composition A, if the mass ratio [P ₂ O ₅ /(SiO ₂ +P ₂ O ₅ )] is too low, the stability may deteriorate during reheating, and if it is too high, there is a partial dispersion ratio Pg , Concerns about the rise of F. Therefore, the mass ratio is preferably within the above range.

Molding glass material of the present embodiment, when the glass composition A, P ₂ O ₅ content relative to the mass of SiO _2, P ₂ O ₅ and B ₂ O ₃ total content ratio of _{[P 2 O 5 / (SiO} 2 +P ₂ O ₅ +B ₂ O ₃ )] The lower limit is preferably 0.00, and more preferably, the order is 0.006, 0.011, 0.016, 0.021. In addition, the upper limit of the mass ratio is preferably 0.20, and the more preferable order is 0.18, 0.16, 0.14, 0.12, 0.11.

In the glass composition A, if the mass ratio [P ₂ O ₅ /(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )] is too high, the partial dispersion ratio Pg and F may increase. Therefore, the mass ratio is preferably within the above range.

Molding glass material of the present embodiment, when the glass composition A, SiO ₂ content of the mass ₂ O ₃ the total content of SiO _2, P ₂ O ₅ and B ratio of _{[SiO 2 / (SiO 2 +} P 2 O ₅ +B ₂ O ₃ )] The lower limit is preferably 0.100, and more preferably 0.200, 0.300, 0.400, 0.500, 0.600, 0.700, 0.800, 0.820, 0.840, 0.860 in order. In addition, the upper limit of the mass ratio is preferably 1.000, and the more preferable order is 0.995, 0.990, 0.985, 0.980, 0.978.

In the glass composition A, the mass ratio [SiO ₂ /(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )] is preferably within the above-mentioned range from the viewpoint of maintaining stability during reheating.

In the glass material for molding of the present embodiment, in the case of glass composition A, _{the lower limit of the ZrO 2} content is preferably 0%, and more preferably 2%, 3%, 4%, and 5% in order. In particular, when stability is more important than the refractive index, _{the lower limit of the ZrO 2} content is preferably 6%, or can also be set to 8%. In addition, _{the upper limit of the ZrO 2} content is preferably 15%, and the more preferable order is 14%, 13%, 12%, 11%, 10%. Especially when stability is more important than the refractive index, _{the upper limit of the ZrO 2} content is preferably 9%, and can also be set to 8%, 7%, or 6%.

In the glass composition A, when _{the lower limit of the ZrO 2} content satisfies the above, a glass having a high refractive index, high dispersibility, and high internal transmittance λτ ₈₀ can be obtained. In addition, when _{the upper limit of the ZrO 2} content satisfies the above, the increase in the partial dispersion ratio Pg and F can be suppressed, and the occurrence of defects when it becomes an optical element can be suppressed, and the meltability and thermal stability of the glass can be maintained.

In the glass material for molding of this embodiment, in the case of glass composition A, _{the lower limit of the Nb 2} O ₅ content is preferably 1%, and the more preferable order is 11%, 21%, 26%, 31%, 34%. , 36%. Especially when stability is more important than the refractive index, _{the lower limit of the Nb 2} O ₅ content is preferably 39%, and can also be set to 41%, 46%, 49%, or 50%. In addition, _{the upper limit of the Nb 2} O ₅ content is preferably 80%, and the more preferable order is 70%, 64%, 59%, 56%, 54%. Especially when stability is more important than the refractive index, _{the upper limit of the Nb 2} O ₅ content is preferably 51%, and it can also be set to 47%, 44%, 43%, or 38%.

In the glass composition A, when _{the lower limit of the Nb 2} O ₅ content satisfies the above, a high refractive index and high dispersibility glass with a reduced partial dispersion ratio Pg,F can be obtained. In addition, Nb ₂ O _{5 is} also a glass component that improves the thermal stability and chemical durability of glass. If the content is too small, Pg and F may increase, and if it is contained excessively, the thermal stability of the glass may deteriorate. Therefore, when _{the upper limit of the Nb 2} O ₅ content satisfies the above, the thermal stability and chemical durability of the glass can be maintained well, and the moldability during reheating can be improved.

In the glass material for molding of this embodiment, in the case of glass composition A, _{the lower limit of the TiO 2} content is preferably 0%, and the more preferable order is 1%, 2%, 3%, and 4% in this order. In addition, the _{upper limit of the TiO 2} content is preferably 20%, and the more preferable order is 15%, 11%, 8%, 6%.

TiO ₂ is a component that contributes to high refractive index and high dispersion in the glass composition A. By _{coexisting with Nb 2} O ₅ , the stability of the glass can be improved while maintaining the high refractive index, and the stability of the glass can be improved during reheating. The stability. On the other hand, if TiO ₂ is introduced excessively, the partial dispersion ratio Pg and F may increase, and the transmittance of the glass in the short wavelength region may decrease. In addition, crystals are formed in a temperature range lower than the glass yield point, which may hinder the productivity of the glass. Therefore, the _{content of TiO 2 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition A, the lower limit of the total content of _{Nb 2} O ₅ and TiO _{2 [Nb 2} O ₅ +TiO ₂ ] is preferably 10%, and more preferably, the order is in order. 20%, 30%, 35%, 38%, 39%, 40%, 41%. Especially when stability is more important than the refractive index, the lower limit of the total content is preferably 45%, and it can also be set to 48%, 51%, 53%, or 55%. In addition, the upper limit of the total content is preferably 80%, and the more preferable order is 75%, 70%, 65%, 62%, 59%, 56%. Especially when stability is more important than the refractive index, the upper limit of the total content is preferably 53%, and it can also be set to 50%, 47%, 44%, or 43%.

In the glass composition A, in order to improve the stability of the glass while maintaining a high refractive index, and to improve the stability during reheating, the total content [Nb ₂ O ₅ +TiO ₂ ] is preferably within the above-mentioned range.

In the glass material for molding of the present embodiment, in the case of glass composition A, the upper limit of the mass ratio [TiO ₂ /Nb ₂ O _{5 ] of the content of TiO 2 to the} content of Nb ₂ O _{5 is} preferably 0.50, and more preferably in the order of Sequence 0.40, 0.30, 0.20, 0.18, 0.16. The lower limit of the mass ratio is preferably 0, and the more preferable order is 0.02, 0.04, 0.06, 0.08, 0.10. The mass ratio may also be zero.

_{In the glass composition A, the mass ratio [TiO 2} /Nb ₂ O ₅ ] is preferably within the above-mentioned range from the viewpoint of suppressing the increase in the partial dispersion ratio Pg and F and increasing the λτ80.

In the glass material for molding of this embodiment, in the case of glass composition A, the lower limit of the mass ratio [P ₂ O ₅ /Nb ₂ O ₅ ] of the _{content of P 2} O _{5 to the} content of Nb ₂ O _{5 is preferably 0.000,} A more preferable sequence is 0.005, 0.010, 0.015, 0.020. In addition, the upper limit of the mass ratio is preferably 0.200, and the more preferable order is 0.150, 0.100, 0.090, 0.080.

_{In the glass composition A, the mass ratio [P 2} O ₅ /Nb ₂ O ₅ ] is preferably within the above-mentioned range from the viewpoint of suppressing the increase in the partial dispersion ratios Pg and F.

Molding glass material of the present embodiment, when the glass composition A, P ₂ O ₅ content of the Nb ₂ O ₅ and TiO ₂ total content mass ratio of _{[P 2 O 5 / (Nb} 2 O 5 + TiO 2 )] The lower limit is preferably 0.000, and the more preferable order is 0.005, 0.010, 0.015, 0.018. In addition, the upper limit of the mass ratio is preferably 0.200, and the more preferable order is 0.150, 0.100, 0.090, 0.080.

In the glass composition A, the mass ratio [P ₂ O ₅ /(Nb ₂ O ₅ +TiO ₂ )] is preferably within the above-mentioned range from the viewpoint of obtaining the required high dispersibility.

In the molding glass material of this embodiment, when the glass is composed of A, the _{upper limit of WO 3} content is preferably 20%, and the more preferable order is 17%, 14%, 11%, 8%, 6%, 4%. , 3%, 2%, 1%, 0.5%, 0.2%. In addition, _{the lower limit of the WO 3} content is preferably 0%. The WO ₃ content can also be 0%.

In the glass composition A, WO ₃ is a component that improves the stability during reheating. On the other hand, the WO ₃ system increases the partial dispersion ratio Pg and F. In addition, it is easy to cause coloration of the glass, and λτ80 is reduced. Therefore, the WO ₃ content is preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition A, the _{upper limit of the Bi 2} O ₃ content is preferably 20%, and the more preferable order is 17%, 14%, 11%, 8%, 6%, 4%, 3%, 2%, 1%, 0.5%, 0.2%. In addition, _{the lower limit of the Bi 2} O ₃ content is preferably 0%. The _{content of Bi 2} O ₃ may also be 0%.

In the glass composition A, Bi ₂ O ₃ has the effect of improving the thermal stability of the glass by containing it in an appropriate amount. On the other hand, if the _{content of Bi 2} O _{3 is} too large, the partial dispersion ratio Pg and F will increase. In addition, the coloring of the glass may increase and λτ80 may decrease. Therefore, the _{content of Bi 2} O _{3 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition A, the total content of _{Nb 2} O ₅ , TiO ₂ , WO ₃ and Bi ₂ O _{3 [Nb 2} O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ The upper limit of] is preferably 80%, and a more preferable sequence is 75%, 70%, 65%, 62%, 59%, 56%. Especially when stability is more important than the refractive index, the upper limit of the total content is preferably 53%, and it can also be set to 50%, 47%, 44%, or 43%. In addition, the lower limit of the total content is preferably 10%, and the more preferable order is 20%, 30%, 35%, 38%, 39%, 40%, 41%. Especially when stability is more important than the refractive index, the lower limit of the total content is preferably 45%, and it can also be set to 48%, 51%, 53%, or 55%.

In the glass composition A, TiO ₂ , WO ₃ and Bi ₂ O ₃ are all components that contribute to high refractive index and high dispersion together with Nb ₂ O _5. Therefore, the total content [Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ ] is preferably within the above range.

Furthermore, in the glass material for molding of this embodiment, in the case of glass composition A, the mass ratio of the _{Nb 2} O ₅ content to the _{total content of Nb 2} O ₅ , TiO ₂ , WO ₃ and Bi ₂ O _{3 [Nb 2} The _{upper limit of O 5} /(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] is better from the viewpoint of maintaining the thermal stability of the glass, increasing the λτ80 of the glass, and improving the stability during reheating Line 1, preferably 0.98, 0.96, 0.94, 0.92 in order. The lower limit of the mass ratio is preferably 0.1, and the more preferable order is 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8.

Further, molding glass material of the present embodiment, when the glass composition A, ZrO ₂ content of the Nb ₂ O _5, by mass TiO _2, WO ₃ and Bi ₂ O ₃ ratio of the total content [ZrO ₂ / ( The _{upper limit of Nb 2} O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )], from the viewpoint of maintaining the thermal stability of the glass, is preferably 1, and the more preferable order is 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.25. In addition, the lower limit of the mass ratio [ZrO ₂ /(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] is, from the viewpoint of increasing the λτ80 of the glass, 001 is preferred, and the order is 0.03. , 0.05, 0.08, 0.09, 0.10, 0.11. In addition, from the viewpoint of maintaining high dispersibility of the glass, _{the upper limit of the mass ratio [ZrO 2} /(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] may be set to 0.02, 0.01, or 0.00.

Furthermore, in the case of the glass of this embodiment, in the case of glass composition A, the _{total content of SiO 2} , P ₂ O ₅ and B ₂ O _{3 is} relative to the total content of Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ The upper limit of the mass ratio [(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )], preferably 5, more preferably in order 4. 3, 2, 1.5, 1.3, 1.1, 1.0, 0.9, 0.8. When paying particular attention to the refractive index, the upper limit of the mass ratio is preferably 0.7, and may be 0.6, 0.5, or 0.45. In addition, the lower limit of the mass ratio is preferably 0.013, and the more preferable order is 0.10, 0.20, 0.30, 0.35, 0.40. When stability is particularly important, the lower limit of the mass ratio is preferably 0.50, and may also be set to 0.60, 0.70, or 0.75.

In the glass composition A, by setting the mass ratio [(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] to the above range, Adjust the refractive index of glass and maintain thermal stability.

In the glass material for molding of this embodiment, when the glass is composed of A, the _{upper limit of Ta 2} O ₅ content is preferably 20%, and the more preferable order is 15%, 10%, 8%, 6%, 4%, 2%, 1%. In addition, the lower limit of the content of _{Ta 2} O _{5 is preferably 0%.} The _{content of Ta 2} O ₅ may also be 0%.

In the glass composition A, Ta ₂ O ₅ is a glass component that has the effect of improving the thermal stability of the glass. On the other hand, if the _{content of Ta 2} O _{5 is} too large, the thermal stability of the glass is reduced, and when the glass is melted, the glass raw material is likely to be left after melting. In addition, it is a high-priced component, which may increase the cost of glass manufacturing. Therefore, the _{content of Ta 2} O _{5 is} preferably within the above range.

Further, molding glass material of the present embodiment, when the glass composition A, Ta ₂ O ₅ with respect to the content of _{Ta 2 O 5, Nb 2 O} 5, TiO 2, WO 3 and Bi ₂ O ₃ in the total content The upper limit of the mass ratio [Ta ₂ O ₅ /(Ta ₂ O ₅ +Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] is preferably 0.9, and the more preferred order is 0.7, 0.5, 0.3, 0.2, 0.1, 0.05. The lower limit of the mass ratio is preferably 0.000.

In glass composition A, from the viewpoint of suppressing the increase in specific gravity and the increase in glass manufacturing cost, the mass ratio [Ta ₂ O ₅ /(Ta ₂ O ₅ +Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ ) ] Preferably within the above range.

In the glass material for molding of this embodiment, in the case of the glass composition A, the _{upper limit of the Li 2} O content is preferably 10%, and the more preferable order is 9%, 8%, 7%, and 6%. The lower limit of the content of Li ₂ O is preferably 0%, and the more preferable order is 1%, 2%, 3%, 3.5%, 4%, 4.5%.

In the molding glass material of this embodiment, when the glass is composed of A, the _{upper limit of Na 2} O content is preferably 30%, and the more preferable order is 25%, 20%, 18%, 16%, 14, 12%. . The lower limit of the Na ₂ O content is preferably 0%, and the more preferable order is 1%, 2%, 3%, 3.5%, 4%, 4.5%, 5%.

In the glass material for molding of the present embodiment, when the glass is composed of A, the _{upper limit of the K 2} O content is preferably 30%, and the more preferable order is 20%, 15%, 10%, 7%, 4%. The lower limit of the K ₂ O content is preferably 0%, and the more preferable order is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%.

In the glass composition A, Li ₂ O, Na ₂ O, and K ₂ O all have the effect of lowering the liquidus temperature and improving the thermal stability of the glass. If these contents are too high, the chemical durability and weather resistance will decrease. Therefore, _{the respective contents of Li 2} O, Na ₂ O, and K ₂ O are preferably within the above-mentioned ranges.

In the glass material for molding of this embodiment, in the case of glass composition A, the lower limit of the total content of _{Li 2} O, Na ₂ O, and K _{2 O [Li 2} O+Na ₂ O+K _{2 O] is preferably 1} %, the better order is 5%, 8%, 10%, 12%, 13%, 14%. In addition, the upper limit of the total content is preferably 40%, and a more preferable order is 35%, 30%, 25%, 22%, 20%, 19%, 18%, 17%.

In the glass composition A, when _{the lower limit of the total content [Li 2} O+Na ₂ O+K ₂ O] satisfies the above, the meltability of the glass can be improved and the rise in the liquidus temperature can be suppressed. Moreover, when the upper limit of the total content satisfies the above, the viscosity of the glass can be improved, the crystallization rate of the glass melt can be reduced, and the stability during reheating can be improved.

In the glass material for molding of this embodiment, in the case of glass composition A, the _{total content of Li 2} O, Na ₂ O, and K ₂ O is the mass ratio with respect to the total content of Nb ₂ O ₅ and TiO _{2 [(Li 2} O +Na ₂ O+K ₂ O)/(Nb ₂ O ₅ +TiO ₂ )] The lower limit is preferably 0.10, and the more preferred order is 0.15, 0.18, 0.21, 0.23, 0.25. In addition, the upper limit of the mass ratio is preferably 0.70, and the more preferable order is 0.65, 0.60, 0.55, 0.50, 0.45.

In the glass composition A, the mass ratio [(Li ₂ O+Na ₂ O+K ₂ O)/(Nb ₂ O ₅ + TiO ₂ )] is preferably within the above range.

Molding glass material of the present embodiment, when the glass composition A, P ₂ O ₅ content of the Li ₂ O, by mass Na ₂ O, K ₂ O and ₂ O ₅ total content of Nb ratio of [P ₂ O ₅ The upper limit of /(Li ₂ O+Na ₂ O+K ₂ O+Nb ₂ O ₅ )] is preferably 0.500, and the more preferred order is 0.400, 0.300, 0.200, 0.100, 0.080, 0.070, 0.060. In addition, the lower limit of the mass ratio is preferably 0, and the more preferable order is 0.005, 0.010, 0.011, 0.012, 0.013, 0.014.

_{In the glass composition A, the mass ratio [P 2} O ₅ /(Li ₂ O+Na ₂ O+K ₂ O+Nb ₂ O ₅ ) from the viewpoint of stabilizing the glass and suppressing the increase in the partial dispersion ratio Pg and F ] Preferably within the above range.

In the glass material for molding of this embodiment, when the glass is composed of A, the _{upper limit of the Cs 2} O content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 3%, 2%, 1 %. The lower limit of the Cs ₂ O content is preferably 0%.

In the glass composition A, Cs ₂ O has the effect of improving the thermal stability of the glass, but if the content of these is too large, the chemical durability and weather resistance will be reduced. Therefore, the _{content of Cs 2} O is preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition A, the total content of _{Li 2} O, Na ₂ O, K ₂ O, and Cs _{2 O [Li 2} O+Na ₂ O+K ₂ O+Cs ₂ O The lower limit of] is preferably 1%, and the more preferable order is 5%, 8%, 10%, 12%, 13%, 14%. In addition, the upper limit of the total content is preferably 40%, and a more preferable order is 35%, 30%, 25%, 22%, 20%, 19%, 18%, 17%.

In the glass composition A, the total content [Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O] is preferably within the above-mentioned range from the viewpoint of maintaining stability during reheating.

Further, molding glass material of the present embodiment, when the glass composition A, Li ₂ O content of the _{Li 2 O, Na 2 O,} K 2 O, Cs ₂ O and the mass ratio of the total content of [Li ₂ The upper limit of O/(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)], from the viewpoint of suppressing the rise of liquidus temperature and suppressing the decrease in weather resistance, the preferred value is 1, and the more preferred sequence is 0.9. , 0.8, 0.7, 0.6, 0.5, 0.45, 0.4. In addition, the lower limit of the mass ratio is preferably 0, and the more preferable order is 0.1, 0.2, 0.25, 0.29, 0.31, 0.33.

Further, molding glass material of the present embodiment, when the glass composition A, Na ₂ O content of the _{Li 2 O, Na 2 O,} K 2 O, Cs ₂ O and the mass ratio of the total content of [Na ₂ The upper limit of O/(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)], from the viewpoint of suppressing the rise in liquidus temperature and suppressing the decrease in weather resistance, the preferred value is 1, and the more preferred sequence is 0.95. , 0.9, 0.85, 0.80, 0.75, 0.70, 0.66. In addition, the lower limit of the mass ratio is preferably 0, and the more preferable order is 0.1, 0.2, 0.25, 0.29, 0.31, 0.33, 0.34.

Further, molding glass material of the present embodiment, when the glass composition A, K ₂ O content of the _{Li 2 O, Na 2 O,} K 2 O, Cs ₂ O and the mass ratio of the total content [K ₂ The upper limit of O/(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)], from the viewpoint of suppressing the rise of liquidus temperature and suppressing the decrease in weather resistance, the preferred value is 1, and the more preferred sequence is 0.9. , 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.28, 0.27. The lower limit of the mass ratio is preferably 0, and the more preferable order is 0.1, 0.15, 0.20, 0.22, 0.24, 0.25.

Furthermore, in the glass material for molding of this embodiment, when the glass composition is A, the _{content of P 2} O _{5 is} relative to Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, Nb ₂ O ₅ , TiO ₂ , The mass ratio of the total content of _{WO 3} and Bi ₂ O _{3 [P 2} O ₅ /(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O+Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] The upper limit is preferably 1, and the more preferred order is 0.5, 0.3, 0.1, 0.08, 0.07, 0.06. In addition, the lower limit of the mass ratio is preferably 0, and the more preferable order is 0.005, 0.008, 0.011, and 0.012.

In glass composition A, by appropriately introducing glass components of Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ , the desired Abbe value νd and partial dispersion ratio Pg,F. However, if these components are introduced into silicate-based glass, the stability during reheating may deteriorate. On the other hand, P ₂ O ₅ is a component that improves the stability during reheating. Therefore, if the mass ratio [P ₂ O ₅ /(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O+Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] is too high, The stability of the glass may deteriorate and the partial dispersion ratio Pg and F may increase. If it is too low, the stability may deteriorate during reheating. Therefore, the mass ratio is preferably within the above range.

In addition, in the glass material for molding of this embodiment, in the case of glass composition A, the _{total content of Li 2} O, Na ₂ O, K ₂ O, and Cs ₂ O is relative to SiO ₂ , P ₂ O ₅ and B ₂ O ₃ mass ratio of the total content _{[(Li 2 O + Na 2} O + K 2 O + Cs 2 O) / (SiO 2 + P 2 O 5 + B 2 O 3)] the upper limit, the preferred system 5, more preferably The order is 4, 3, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6. In addition, the lower limit of the mass ratio is preferably 0.02, and the more preferable order is 0.1, 0.2, 0.3, 0.4, 0.45.

In glass composition A, if the mass ratio [(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)/(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )] is too low, remove the glass transition point In addition to the increase in Tg, the solubility may deteriorate and the partial dispersion ratio Pg and F may increase. In addition, if it is too high, in addition to lowering the viscosity during melting of the glass and lowering the thermal stability of the melt, there is also a possibility that the stability during reheating may deteriorate.

In the glass material for molding of this embodiment, in the case of glass composition A, the _{total content of Li 2} O, Na ₂ O, K ₂ O, and Cs ₂ O is relative to Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ The upper limit of the mass ratio of the total content of _{O 3 [(Li 2} O+Na ₂ O+K ₂ O+Cs ₂ O)/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] is preferably 4 , The better order is 3.2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5. In addition, the lower limit of the mass ratio is preferably 0.015, and the more preferable order is 0.100, 0.200, and 0.300 in that order.

In glass composition A, if the mass ratio [(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] is too low, There is a concern that the dispersion ratio of Pg and F may increase and the penetration rate may deteriorate. Moreover, if it is too high, in addition to the increase in the Abbe number and the decrease in the refractive index, there is also a risk of deterioration in stability during reheating.

In the glass material for molding of this embodiment, when the glass composition is A, the upper limit of the MgO content is preferably 20%, and the more preferable order is 14%, 9%, 4%, 2%, 1%. The upper limit can also be 0%. In addition, the lower limit of the MgO content is preferably 0%. Especially when increasing the specific resistance of the glass to increase the melting efficiency, the lower limit of the MgO content is preferably 1%, and can also be set to 2%, 4%, or 6%.

In the molding glass material of the present embodiment, when the glass composition is A, the upper limit of the CaO content is preferably 20%, and the more preferable order is 14%, 9%, 4%, 2%, 1%. The upper limit can also be 0%. In addition, the lower limit of the CaO content is preferably 0%. Especially when increasing the specific resistance of the glass to increase the melting efficiency, the lower limit of the CaO content is preferably 1%, and can also be set to 2%, 4%, 6%, or 8%.

In the molding glass material of the present embodiment, when the glass composition is A, the upper limit of the SrO content is preferably 20%, and the more preferable order is 14%, 9%, 4%, 2%, 1%. The upper limit can also be 0%. In addition, the lower limit of the SrO content is preferably 0%. Especially when increasing the specific resistance of the glass to increase the melting efficiency, the lower limit of the SrO content is preferably 1%, and can also be set to 2%, 4%, 6%, or 8%.

In the molding glass material of the present embodiment, when the glass composition is A, the upper limit of the BaO content is preferably 20%, and the more preferable order is 14%, 9%, 4%, 2%, 1%. The upper limit can also be 0%. In addition, the lower limit of the BaO content is preferably 0%. Especially when increasing the specific resistance of the glass to increase the melting efficiency, the lower limit of the BaO content is preferably 1%, and can also be set to 2%, 4%, 6%, or 8%.

In the glass composition A, MgO, CaO, SrO, and BaO are all glass components that have the function of improving the thermal stability of the glass and the resistance to devitrification. However, if the content of these glass components is too high, the specific gravity will increase and high dispersibility will be impaired, and the thermal stability and devitrification resistance of the glass will decrease. Therefore, the respective contents of the glass components are preferably within the above-mentioned ranges.

In the molding glass material of the present embodiment, when the glass composition is A, the upper limit of the ZnO content is preferably 20%, and the more preferable order is 14%, 9%, 4%, 2%, 1%. The upper limit can also be 0%. In addition, the lower limit of the ZnO content is preferably 0%. Especially when the specific resistance of the glass is increased to increase the melting efficiency, or the glass transition point is lowered, the lower limit of the ZnO content is preferably 1%, and can also be set to 2%, 4%, or 6%.

In the glass composition A, ZnO is a glass component that has the effect of improving the thermal stability of the glass. However, if the ZnO content is too large, the specific gravity may increase. Therefore, the ZnO content is preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition A, the upper limit of the total content of MgO and CaO [MgO+CaO] is preferably 20%, and the more preferable order is 14%, 9%, 4%. , 2%, 1%. The upper limit can also be 0%. In addition, the lower limit of the total content is preferably 0%. From the viewpoint of not hindering high dispersion and maintaining thermal stability, the total content is preferably within the above-mentioned range.

Furthermore, in the glass material for molding of this embodiment, when the glass composition is A, the upper limit of the total content of MgO, CaO, SrO, BaO, and ZnO [MgO+CaO+SrO+BaO+ZnO] is preferably 20% , The better order is 14%, 9%, 4%, 2%, 1%. The upper limit can also be 0%. In addition, the lower limit of the total content is preferably 0%. Especially when increasing the specific resistance of the glass to increase the melting efficiency, the lower limit of the total content is preferably 1%, and can also be set to 2%, 4%, 6%, or 8%. From the viewpoint of suppressing an increase in specific gravity, without hindering high dispersion, and maintaining thermal stability, the total content is preferably within the above-mentioned range.

Furthermore, in the glass material for molding of this embodiment, when the glass composition is A, the total content of MgO, CaO, SrO, BaO, and ZnO is relative to the total of Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O The upper limit of the content mass ratio [(MgO+CaO+SrO+BaO+ZnO)/(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)] is preferably 20, and the more preferred order is 18, 16, 14. In addition, the lower limit of the mass ratio is preferably 0, and the more preferable order is 5, 8, 10, 12, and 13 in order. The mass ratio may also be zero. From the viewpoint of suppressing the increase in the specific gravity of the glass, the viewpoint of high refractive index and high dispersion while improving the melting property by increasing the glass filling rate, and the viewpoint of maintaining the specific resistance of the glass appropriately, the mass ratio is preferably within the above range .

In the glass material for molding of this embodiment, in the case of the glass composition A, the _{upper limit of the La 2} O ₃ content is preferably 20%, and the more preferable order is 17%, 14%, and 12% in that order. When the stability is more important than the refractive index, _{the upper limit of the La 2} O ₃ content can also be set to 9%, 7%, 5%, 3%, 2%, or 1%. The upper limit can also be 0%. In addition, _{the lower limit of the La 2} O ₃ content is preferably 0%. In particular, when the refractive index is increased while maintaining the content of the glass forming component, _{the lower limit of the La 2} O ₃ content is preferably 1%, and may be 2%, 4%, or 6%.

In the glass composition A, if the La ₂ O ₃ content is too large, the high dispersion of the glass is suppressed, and the thermal stability is reduced. Therefore, the _{content of La 2} O _{3 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of the glass composition A, the _{upper limit of the Y 2} O ₃ content is preferably 20%, and the more preferable order is 17%, 14%, and 12% in that order. When the stability is more important than the refractive index, _{the upper limit of the Y 2} O ₃ content can also be set to 9%, 7%, 5%, 3%, 2%, or 1%. The upper limit can also be 0%. In addition, _{the lower limit of the Y 2} O ₃ content is preferably 0%. In particular, when the refractive index is increased while maintaining the content of the glass forming component, _{the lower limit of the Y 2} O ₃ content is preferably 1%, and may be 2%, 3%, or 5%.

In the glass composition A, if the Y ₂ O ₃ content is excessively increased, the high dispersion of the glass is suppressed, the thermal stability is reduced, and the glass is easily devitrified during production. Therefore, the _{content of Y 2} O _{3 is} preferably within the above range.

In the molding glass material of the present embodiment, when the glass composition is A, the _{upper limit of the Sc 2} O ₃ content is preferably 3%, and the more preferable order is 2%, 1.5%, 1%, 0.5%. The upper limit can also be 0%. In addition, the lower limit of the content of _{Sc 2} O _{3 is preferably 0%.}

In the molding glass material of the present embodiment, when the glass composition is A, the _{upper limit of the HfO 2} content is preferably 3%, and the more preferable order is 2%, 1.5%, 1%, 0.5%. The upper limit can also be 0%. In addition, _{the lower limit of the HfO 2} content is preferably 0%.

Sc ₂ O ₃ and HfO ₂ have the effect of improving the high dispersibility of the glass in the glass composition A, but they are high-priced components. Therefore, _{the contents of Sc 2} O ₃ and HfO ₂ are preferably within the above-mentioned ranges.

In addition, the HfO ₂ system contains a certain amount in the ZrO _{2 raw material.} Therefore, _{the glass containing ZrO 2} will contain a certain amount of HfO ₂ . Therefore, in the glass material for molding of the first embodiment, in the case of glass composition A, the mass ratio [HfO ₂ /ZrO _{2 ] of the HfO 2} content to the ZrO ₂ content should also be set within a predetermined range. For example, the lower limit of the mass ratio [HfO ₂ /ZrO ₂ ] may be 0.005, or may be 0.010, 0.013, or 0.015. On the other hand, the upper limit of the mass ratio may be 0.05, or 0.040, 0.030, 0.020, or 0.018. From the viewpoint of suppressing the melting of the components of the refractory bricks into the glass, the glass preferably contains a small amount of ZrO ₂ , and therefore, the HfO ₂ content is preferably within the above-mentioned range.

In the glass material for molding of this embodiment, when the glass composition is A, the _{upper limit of the Lu 2} O ₃ content is preferably 3%, and the more preferable order is 2%, 1.5%, 1%, 0.5%. The upper limit can also be 0%. In addition, the lower limit of the content of _{Lu 2} O _{3 is preferably 0%.}

Lu ₂ O ₃ has the effect of improving the high dispersibility of the glass in the glass composition A, but because of its large molecular weight, it is also a glass component that leads to an increase in the specific gravity of the glass. Therefore, the _{content of Lu 2} O _{3 is} preferably within the above range.

In the molding glass material of the present embodiment, when the glass composition is A, the _{upper limit of the GeO 2} content is preferably 3%, and the more preferable order is 2%, 1.5%, 1%, 0.5%. The upper limit can also be 0%. In addition, _{the lower limit of the GeO 2} content is preferably 0%.

GeO ₂ has the effect of improving the high dispersibility of the glass in the glass composition A, but it is a very high-priced component among the commonly used glass components. Therefore, from the viewpoint of reducing glass manufacturing costs, the GeO ₂ content is preferably within the above-mentioned range.

In the glass material for molding of this embodiment, in the case of the glass composition A, the _{upper limit of the Gd 2} O ₃ content is preferably 3%, and the more preferable order is 2%, 1.5%, 1%, 0.5%. The upper limit can also be 0%. In addition, the lower limit of the content of _{Gd 2} O _{3 is preferably 0%.}

In the glass composition A, if the Gd ₂ O ₃ content is excessively increased, the thermal stability of the glass will decrease. In addition, if the Gd ₂ O ₃ content is excessively increased, the specific gravity of the glass will increase, so it is best not to. Therefore, from the viewpoint of suppressing an increase in specific gravity while maintaining a good thermal stability of the glass, the _{content of Gd 2} O _{3 is} preferably within the above-mentioned range.

In the glass material for molding of the present embodiment, when the glass composition is A, the _{upper limit of the Yb 2} O ₃ content is preferably 3%, and the more preferable order is 2%, 1.5%, 1%, 0.5%. The upper limit can also be 0%. In addition, _{the lower limit of the Yb 2} O ₃ content is preferably 0%.

In the glass composition A, since _{the molecular weight of Yb 2} O ₃ is larger than that of La ₂ O ₃ , Gd ₂ O ₃ , and Y ₂ O ₃ , the specific gravity of the glass increases. If the specific gravity of the glass increases, the quality of the optical element will increase. For example, when a large-mass lens is assembled in an auto-focusing type imaging lens, the power required to drive the lens during auto-focusing will increase, resulting in intense battery consumption. Therefore, it is better to reduce the Yb ₂ O ₃ content in order to suppress the increase in the specific gravity of the glass.

Furthermore, in the glass composition A, if the _{content of Yb 2} O _{3 is} too large, the thermal stability of the glass will decrease, and absorption in the near-infrared region is likely to occur. From the viewpoints of maintaining the transmittance of the glass in the near-infrared region, preventing a decrease in thermal stability, and suppressing an increase in specific gravity, the Yb ₂ O ₃ content is preferably within the above-mentioned range.

In the case of the glass material for molding of this embodiment, when the glass composition is A, it is preferable to mainly consist of the above-mentioned glass components (ie, SiO ₂ , P ₂ O ₅ , B ₂ O ₃ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , Ta ₂ O ₅ , Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, MgO, CaO, SrO, BaO, ZnO, La ₂ O ₃ , Y ₂ O ₃ , Sc ₂ O ₃ , HfO ₂ , Lu ₂ O ₃ , GeO ₂ , Gd ₂ O ₃ , and Yb ₂ O ₃ ), the lower limit of the total content of the above-mentioned glass components is preferably 95.5%, and the more preferable order depends on Sequence line is 96.0%, 96.5%, 97.0%, 97.5%, 98.0%, 98.5%, 99.0%.

In addition, it is preferable that the glass material for molding of the present embodiment is basically composed of the above-mentioned glass components, but it may contain other components within a range that does not impair the effects of the present invention. In addition, the present invention does not exclude the inclusion of unavoidable impurities.

(Other ingredients) Pb, As, Cd, Tl, Be, and Se are all toxic. Therefore, it is better not to contain these elements in the glass component of the glass material for molding in this embodiment.

U, Th, and Ra are all radioactive elements. Therefore, it is better not to contain these elements in the glass component of the glass material for molding in this embodiment.

V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm series will cause the color of the glass to increase and become the source of fluorescence. Therefore, it is better not to contain these elements in the glass component of the glass material for molding in this embodiment.

Sb(Sb ₂ O ₃ ) and Ce(CeO ₂ ) are arbitrarily addable elements with clarifying agent function. Among them, Sb (Sb ₂ O ₃ ) is a clarifying agent with a greater clarifying effect, but it can also promote the oxidation of easily reduced components due to a small amount of introduction, and has the effect of increasing λτ80. The clarification effect of Ce(CeO ₂ ) is smaller than that of Sb(Sb ₂ O ₃ ). _{If Ce(CeO 2} ) is added in a large amount, there is a tendency for glass coloring to increase.

The Sb ₂ O ₃ content is expressed as an outer percentage. That is, when the total content of all glass components other than _{Sb 2} O ₃ and CeO _{2 is 100% by mass, the upper limit of the Sb 2} O ₃ content is preferably 1.000% by mass, and the more preferable order is 0.500% by mass and 0.300% by mass. , 0.100% by mass, 0.080% by mass, 0.060% by mass, and 0.040% by mass. In addition, _{the lower limit of the Sb 2} O ₃ content is preferably 0.000% by mass, and more preferably, the order is 0.001% by mass, 0.003% by mass, 0.005% by mass, 0.010% by mass, 0.015% by mass, and 0.020% by mass. In addition, because Sb ₂ O ₃ itself also shifts the penetration absorption end of the glass toward the long wavelength, from the viewpoint of maximizing the transmittance of the glass in the short wavelength region, the _{content of Sb 2} O ₃ can also be less than 0.008% by mass. , And it may be 0.004% by mass or less, or 0.000% by mass.

The CeO ₂ content is also expressed as an additional ratio. That is, when the total content of all glass components other than _{CeO 2} and Sb ₂ O _{3 is 100% by mass, the upper limit of CeO 2} content is preferably 1.000% by mass, and the more preferable order is 0.500% by mass, 0.300% by mass, and 0.100. Mass%, 0.080% by mass, 0.060% by mass, and 0.040% by mass. In addition, _{the lower limit of the CeO 2} content is preferably 0.000% by mass, and more preferably, the order is 0.005% by mass, 0.010% by mass, 0.015% by mass, and 0.020% by mass. The CeO ₂ content may also be 0% by mass.

(Having the glass characteristics of glass composition A) ＜Abbe value νd＞ In the glass material for molding of the present embodiment, in the case of the glass composition A, the upper limit of the Abbe number νd is preferably 50, and may be 45, 40, 35, 33, 31, or 30. In addition, the lower limit of the Abbe number νd is preferably 15, and may be 17, 18, 19, 20, 21, 22, 23, or 24.

By setting the Abbe number νd in the above range, a highly dispersible glass can be obtained. The Abbe number νd can be controlled by adjusting the contents of Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ that contribute to the highly dispersed glass components.

<Refractive index nd> In the case of the glass composition A in the glass material for molding of the present embodiment, the lower limit of the refractive index nd may be 1.65, or 1.70, 1.72, 1.74, 1.76, or 1.80. In addition, the upper limit of the refractive index nd may be 2.30, or may be 2.10, 2.00, or 1.90. The refractive index can be controlled by adjusting the contents of Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ O ₃ that contribute to the high refractive index of the glass component.

<Glass transition temperature Tg> In the glass material for molding of this embodiment, when the glass composition is A, the preferred order of the upper limit of the glass transition temperature Tg is 700°C, 680°C, 670°C, 660°C, 650 ℃, 640℃, 630℃, 620℃, 610℃, 600℃, 590℃, 580℃. In addition, the lower limit of the glass transition temperature Tg is not particularly limited, but is preferably 200°C, and more preferably 300°C, 400°C, and 450°C in this order. The glass transition temperature Tg is adjusted by adjusting the mass ratio [(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )], etc. controllable.

When the upper limit of the glass transition temperature Tg satisfies the above, the increase in the molding temperature and annealing temperature during glass reheating can be suppressed, and the thermal damage to the reheat molding equipment and annealing equipment can be reduced.

When the lower limit of the glass transition temperature Tg satisfies the above, the glass of the present invention can maintain the moldability during reheating and the thermal stability of the glass while having the required Abbe number, refractive index, or transmittance.

＜Specific gravity＞ In the glass material for molding of this embodiment, when the glass is composed of A, the upper limit of the specific gravity is preferably 4.3, and the more preferable order is 4.1, 4.0, 3.9, 3.8, 3.7, 3.6. The lower limit of the specific gravity is not particularly limited, and is usually 2.0, preferably 2.5.

The specific gravity is measured by a measurement method whose repeatability measurement accuracy is within the range of ±0.001 to ±0.002.

＜λτ80＞ In the case of glass composition A, use glass samples with a thickness of 2.0mm±0.1mm and 10.0mm±0.1mm, and measure the spectral transmittance in the wavelength range of 200~700nm according to JOGIS17 (method for measuring the internal transmittance of optical glass). The wavelength at which the internal transmittance at a thickness of 10 mm becomes 80% is λτ80.

In the glass material for molding of the present embodiment, in the case of glass composition A, the upper limit of λτ80 is preferably 395 nm, and in this order, 390 nm, 385 nm, 380 nm, 375 nm, and 370 nm are more preferable. The smaller the value, the better. The lower limit of λτ80 is not particularly limited, and is usually 250 nm. From the viewpoint of suppressing ultraviolet light transmittance, it may be 300 nm or 320 nm.

＜λ70＞ In the case of glass composition A, for a glass sample with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance is measured in the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance becomes 70% is λ70.

In the molding glass material of this embodiment, in the case of glass composition A, the upper limit of λ70 is preferably 445 nm, and more preferably, the order is 440 nm, 430 nm, 420 nm, 410 nm, 400 nm, 390 nm, and 380 nm in this order. The lower limit of λ70 is not particularly limited, and it is usually 255 nm. From the viewpoint of suppressing ultraviolet light transmittance, it may be 305 nm or 325 nm.

In addition, in the present invention, when the glass composition is A, it has a high refractive index and a partial dispersion ratio of Pg, f is small. Therefore, even if the glass cooling rate in step 3 described later is set to one tenth, the dispersion change of the glass can be suppressed. For example, when comparing the glass obtained in step 3 at the cooling rate described later with the glass obtained at one-tenth of the cooling rate, the change in Abbe number Δνd is preferably greater than -0.10, more preferably greater than -0.09, and The lower limit is better in the order of -0.08, -0.07, -0.06, -0.05, -0.04, -0.03. In addition, when combined with a low dispersion lens, from the viewpoint of effectively correcting chromatic aberration, the Abbe value νd of the glass material of this embodiment is preferably 50 or less. Therefore, the upper limit of the above Δνd is +0.10, and the more preferable order is +0.08, +0.06, +0.04, +0.02, +0.01. Especially when the Abbe number is 35 or less, preferably 30 or less, the upper limit of Δνd is preferably +0.005, and more preferably, it may be +0.00, -0.01, -0.02, or -0.03.

<Average linear expansion coefficient α _L > In the glass material for molding of this embodiment, when the glass composition is A, the lower limit of the _{average linear expansion coefficient α L} ^{at -30 to 70°C is preferably 0.70×10 -5} ℃ ^-1 . The better order is 0.71×10 ^-5 ℃ ^-1 , 0.72×10 ^-5 ℃ ^-1 , 0.73×10 ^-5 ℃ ^-1 , 0.74×10 ^-5 ℃ ^-1 , 0.75×10 ^-5 ℃ ^-1 , 0.76×10 ^-5 ℃ ^-1 , 0.77×10 ^-5 ℃ ^-1 , 0.78×10 ^-5 ℃ ^-1 , 0.79×10 ^-5 ℃ ^-1 . In addition, the upper limit of the average linear expansion coefficient α _L , from the viewpoint of maintaining the stability of the glass and obtaining the required optical properties, can be exemplified as 1.10×10 ^-5 ℃ ^-1 , preferably 1.05×10 ^-5 ℃ ^-1 or less , The better order is 1.00×10 ^-5 ℃ ^-1 , 0.96×10 ^-5 ℃ ^-1 , 0.92×10 ^-5 ℃ ^-1 , 0.88×10 ^-5 ℃ ^-1 , 0.84×10 ^-5 ℃ ^{- 1} .

In the case of glass composition A, by setting the average linear expansion coefficient α _{L from} -30 to 70°C in the above range, a molding glass material that can be used in a wide temperature environment can be obtained.

The average linear expansion coefficient α _L is measured in accordance with the regulations of JOGIS16. The sample system is a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. In a state where a load of 98 mN is applied to the sample, the sample is heated at a constant rate of 4°C per minute, and the temperature and sample elongation are measured every 1 second. The average linear expansion coefficient α _L is the average value of the linear expansion coefficient at -30~70℃.

In addition, although JOGIS16 stipulates that "the average linear expansion coefficient is ^{expressed in units of 10 -7} ℃ ^-1 to the first place of the integer", in this manual, the average linear expansion coefficient α _L is set to [10 ^-5 ·℃ ^-1 ] Set as the display unit.

In this manual, the average linear expansion coefficient α _L system uses [10 ^-5 ·℃ ^-1 ] as the unit of expression, and even if the unit system uses [10 ^-5 ·K ^-1 ], the average linear expansion coefficient α _L The value of is still the same.

(Glass composition B) Next, regarding the case where the glass material for molding of the present embodiment has the glass composition B, the content and ratio of the glass components, and the glass characteristics will be described.

In the case of the glass composition B in this embodiment, the glass composition is based on SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, MgO on the basis of oxides. , CaO, SrO, BaO, ZnO, La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , WO ₃ , and _{the content of Bi 2} O ₃ expressed by mass%, Set as C(SiO ₂ ), C(B ₂ O ₃ ), C(Al ₂ O ₃ ), C(Li ₂ O), C(Na ₂ O), C(K ₂ O), C(Cs ₂ O), C(MgO), C(CaO), C(SrO), C(BaO), C(ZnO), C(La ₂ O ₃ ), C(Gd ₂ O ₃ ), C(Y ₂ O ₃ ), C(ZrO ₂ ), C(TiO ₂ ), C(Nb ₂ O ₅ ), C(WO ₃ ), and C(Bi ₂ O ₃ ).

The content of glass components other than the above is _{represented by the mass% of Ta 2} O ₅ , Sc ₂ O ₃ , HfO ₂ , Lu ₂ O ₃ , GeO ₂ , and Yb ₂ O ₃ , respectively, as C(Ta ₂ O ₅ ), C(Sc ₂ O ₃ ), C(HfO ₂ ), C(Lu ₂ O ₃ ), C(GeO ₂ ), and C(Yb ₂ O ₃ ).

When the present embodiment has glass composition B, SiO ₂ , BO _1.5 , AlO _1.5 , LiO _0.5 , NaO _0.5 , KO _0.5 , CsO _0.5 , MgO, CaO, SrO, BaO, ZnO, LaO _1.5 , GdO _1.5 , YO _1.5 , ZrO ₂ , TiO ₂ , NbO _2.5 , WO ₃ , and BiO _1.5 each of the chemical formulas are set to M (SiO ₂ ), M (BO _1.5 ), M (AlO _1.5 ), M (LiO _0.5 ), M (NaO _0.5 ), M (KO _0.5 ), M (CsO _0.5 ), M (MgO), M (CaO), M (SrO), M (BaO), M (ZnO), M (LaO _1.5 ), M ( GdO _1.5 ), M(YO _1.5 ), M(ZrO ₂ ), M(TiO ₂ ), M(NbO _2.5 ), M(WO ₃ ), and M(BiO _1.5 ).

_{The chemical formulae of TaO 2.5} , ScO _1.5 , HfO ₂ , LuO _1.5 , GeO ₂ , and YbO _1.5 other than the above-mentioned glass components are set to M (TaO _2.5 ), M (ScO _1.5 ), M (HfO ₂ ), M (LuO _1.5 ), M(GeO ₂ ), and M(YbO _1.5 ).

That is, when the present embodiment has the glass composition B, for example, the related oxide X _y O _z , the content expressed in mass% can be C(X _y O _z ). In addition, _{the chemical formula weight of the cation (cation "X") of the oxide X y} O _z (cation "X") per 1 mol (that is, the chemical formula weight of XO _z/y ) can be set to M(XO _z/y ). However, when expressed in the formula {C(X _y O _z )/M(XO _z/y )}, it is the cation "X" content expressed in terms of mole %, that is, the "X" content expressed in terms of cation %.

For the glass material for molding of this embodiment, in the case of glass composition B, A1={C(B ₂ O ₃ )/M(BO _1.5 )}/{C(B ₂ O ₃ )/M(BO _1.5 ) +C(SiO ₂ )/M(SiO ₂ )}, the lower limit of A1 is preferably 1/3, and the more preferable order is 1.1/3, 1.2/3, 1.3/3, 1.4/3, 1.5/3 , 1.6/3, 1.7/3, 1.8/3, 1.9/3. Furthermore, the upper limit of A1 is preferably 3.0/3, and the more preferable order is 2.9/3, 2.8/3, 2.7/3, 2.6/3, 2.5/3, 2.4/3, 2.3/3.

In the glass composition B, by setting A1 in the above range, a glass material for molding with a large _{average linear expansion coefficient α L at -30 to 70°C and low dispersion can be obtained.} In addition, the temperature coefficient (dn/dT) of the relative refractive index of the glass can be reduced. _{In addition, even when La 2} O ₃ is contained in a large amount, it is possible to suppress the deterioration of the thermal stability of the glass. On the other hand, if A1 is too small, if a large amount of _{La 2} O ₃ and Y ₂ O ₃ are glass components that _{increase the refractive index nd and prevent the decrease of the average linear expansion coefficient α L} , the glass may become unstable. . In addition, if A1 is too large, the stability, chemical durability, and mechanical properties of the glass may decrease.

For the glass material for molding of this embodiment, in the case of glass composition B, set B1={C(BaO)/M(BaO)+C(SrO)/M(SrO)}/{C(Li ₂ O)/ M(LiO _0.5 )+C(Na ₂ O)/M(NaO _0.5 )+C(K ₂ O)/M(KO _0.5 )+C(Cs ₂ O)/M(CsO _0.5 )+C(MgO)/ When M(MgO)+C(CaO)/M(CaO)+C(SrO)/M(SrO)+C(BaO)/M(BaO)}, the lower limit of B1 is preferably 0.62, and the better order is in order It is 0.63, 0.65, 0.67, 0.69, 0.71, 0.73, 0.75, 0.77, 0.79, 0.81, 0.83, 0.85, 0.87. In addition, the upper limit of B1 is preferably 1.00, and the more preferable order is 0.99 and 0.98 in this order. B1 can also be 1.00.

In the glass composition B, by setting B1 in the above range, a molding glass material having a large _{average linear expansion coefficient α L and a high refractive index can be obtained.} In addition, the decrease in thermal stability can be suppressed in a state where the average linear expansion coefficient α _{L is increased.} On the other hand, if B1 is too small, the average linear expansion coefficient α _L and the refractive index nd may decrease, and the stability of the glass may be impaired.

For the glass material for molding of this embodiment, in the case of glass composition B, set C1={C(BaO)/M(BaO)+C(Li ₂ O)/M(LiO _0.5 )}/{C(Na ₂ O)/M(NaO _0.5 )+C(K ₂ O)/M(KO _0.5 )+C(SiO ₂ )/M(SiO ₂ )+C(TiO ₂ )/M(TiO ₂ )+C(Nb ₂ When O ₅ )/M(NbO _2.5 )+C(WO ₃ )/M(WO ₃ )}, the lower limit of C1 is preferably 8/9, and the more preferable order is 8.2/9, 8.4/9, 8.6/ 9, 8.8/9, 9.0/9, 9.2/9, 9.4/9, 9.5/9. In addition, the upper limit of C1 is preferably 27/9, and the more preferable order is 25/9, 23/9, 21/9, 19/9, 17/9, 15/9, 13/9, 12/9.

In the glass composition B, by setting C1 in the above-mentioned range, a glass material for molding with a large _{average linear expansion coefficient α L, high refractive index and low dispersion can be obtained.} In addition, the temperature coefficient (dn/dT) of the relative refractive index of the glass can be reduced. On the other hand, if C1 is too small, the average linear expansion coefficient α _{L may} decrease, and the glass may lose high refraction and low dispersion. In addition, if C1 is too large, the stability of the glass may decrease.

In the glass material for molding of this embodiment, in the case of glass composition B, D1=C(Gd ₂ O ₃ )+C(ZnO)+C(TiO ₂ )+C(Nb ₂ O ₅ )+C( For WO ₃ )+C(ZrO ₂ ), the upper limit of D1 is preferably 13.50, and the more preferable order is 12.00, 11.00, 10.50, 10.00, 9.50, 9.00, 8.50. In addition, the lower limit of D1 is preferably 0, and the more preferable order is 1, 2, 3, 4, 5, 6, 7, and 8. D1 can also be 0.

In the glass composition B, by setting D1 in the above range, it is possible to suppress the decrease in the average linear expansion coefficient α _L. In addition, it is possible to obtain a molding glass material that suppresses high dispersion, high refractive index and low dispersion. It also has the effect of not increasing the temperature coefficient (dn/dT) of the relative refractive index of the glass. D1 can also be set to 0, in order to adjust optical constants such as Abbe value νd, D1 can also be set to be greater than zero. On the other hand, if D1 is too large, the average linear expansion coefficient α _{L may} decrease, and the glass may lose its high refraction and low dispersion properties.

In the glass material for molding of this embodiment, in the case of glass composition B, set E1={C(La ₂ O ₃ )+C(Gd ₂ O ₃ )+C(Y ₂ O ₃ )}/{C( When SiO ₂ )+C(B ₂ O ₃ )+C(Al ₂ O ₃ )}, the lower limit of E1 is preferably 1.25, and the more preferable order is 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70. In addition, the upper limit of E1 is preferably 3.00, and the more preferable order is 2.80, 2.60, 2.40, 2.20, 2.10.

In the glass composition B, by setting E1 in the above range, a glass material for molding with a high refractive index and low dispersion can be obtained. On the other hand, if E1 is too small, the glass may lose high refraction and low dispersion, and the average linear expansion coefficient α _{L may} decrease. In addition, if E1 is too large, the thermal stability of the glass may decrease.

In the glass material for molding of this embodiment, when the glass composition is B, F1={C(Gd ₂ O ₃ )/M(GdO _1.5 )+C(ZnO)/M(ZnO)+C(TiO ₂ )/M(TiO ₂ )+C(Nb ₂ O ₅ )/M(NbO _2.5 )+C(WO ₃ )/M(WO ₃ )+C(Bi ₂ O ₃ )/M(BiO _1.5 ))/{ When C(Y ₂ O ₃ )/M(YO _1.5 )}, the upper limit of F1 is preferably 2.0, and the more preferable order is 1.8, 1.6, 1.4, 1.2, 1.1, 1.0, 0.9, 0.8, 0.6. In addition, the lower limit of F1 is preferably 0, and the more preferable order is 0.1, 0.2, 0.3, 0.4. F1 can also be 0.

In the glass composition B, by setting F1 in the above-mentioned range, a molding glass material having a large _{average linear expansion coefficient α L can be obtained.} In addition, it is possible to suppress a decrease in the thermal stability of the glass. F1 may also be 0, but to adjust optical constants such as Abbe value νd, F1 may be set to be greater than 0. On the other hand, if F1 is too large, the average linear expansion coefficient α _{L may} decrease, and the glass may lose its high refraction and low dispersion properties.

In the glass material for molding of this embodiment, in the case of glass composition B, G1=C(BaO)/M(BaO)+C(La ₂ O ₃ )/M(LaO _1.5 )+C(Li ₂ O When )/M(LiO _0.5 )+C(Y ₂ O ₃ )/M(YO _1.5 ), the lower limit of G1 is preferably 0.47, and the more preferable order is 0.475, 0.48, 0.485. In addition, the upper limit of G1 is preferably 0.60, and more preferably the order is 0.59, 0.58, 0.57, 0.56, 0.55, 0.54, 0.53.

In the glass composition B, from the viewpoint of obtaining a glass material for molding with a high refractive index and low dispersion while _{suppressing a decrease in the average linear expansion coefficient α L, it is preferable to set G1 in the above-mentioned range.} On the other hand, if G1 is too small, the average linear expansion coefficient α _{L may} decrease, and the glass may lose its high refraction and low dispersion properties. In addition, if G1 is too large, the thermal stability of the glass may decrease.

In this embodiment, in the case of glass composition B, _{the lower limit of {C(B 2} O ₃ )/M(BO _1.5 )+C(SiO ₂ )/M(SiO ₂ )} is preferably 0.35, more preferably The sequence is 0.37, 0.39, 0.41, 0.43, 0.45, 0.47. In addition, the upper limit is preferably 0.75, and the more preferable order is 0.73, 0.71, 0.69, 0.67, 0.65, 0.63, 0.61, 0.59.

In the glass composition B, from the viewpoint of obtaining a glass material for molding with a large _{average linear expansion coefficient α L and low dispersion, {C(B 2} O ₃ )/M(BO _1.5 )+C(SiO ₂ )/M(SiO ₂ )} It is better to set the above range.

In this embodiment, when the glass composition is B, the lower limit of {C(BaO)/M(BaO)+C(SrO)/M(SrO)} is preferably 0.15, and the more preferable order is 0.16, 0.17, 0.18, 0.19, 0.20. In addition, the upper limit is preferably 0.30, and the more preferable order is 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23.

In the glass composition B, from the viewpoint of obtaining _{a glass material for high refractive index molding with a large average linear expansion coefficient α L} , {C(BaO)/M(BaO)+C(SrO)/M(SrO)} is best set For the above range.

In this embodiment, when the glass composition is B, {C(Li ₂ O)/M(LiO _0.5 )+C(Na ₂ O)/M(NaO _0.5 )+C(K ₂ O)/M(KO _0.5 )+C(Cs ₂ O)/M(CsO _0.5 )+C(MgO)/M(MgO)+C(CaO)/M(CaO)+C(SrO)/M(SrO)+C(BaO) The lower limit of /M(BaO)} is preferably 0.15, and the more preferable order is 0.16, 0.17, 0.18, 0.19, 0.20. In addition, the upper limit is preferably 0.35, and the more preferable order is 0.34, 0.33, 0.32, 0.31, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23.

In the glass composition B, from the viewpoint of obtaining a glass material for high refractive index molding with a large _{average linear expansion coefficient α L , {C(Li 2} O)/M(LiO _0.5 )+C(Na ₂ O)/M(NaO _0.5 )+C(K ₂ O)/M(KO _0.5 )+C(Cs ₂ O)/M(CsO _0.5 )+C(MgO)/M(MgO)+C(CaO)/M(CaO)+C (SrO)/M(SrO)+C(BaO)/M(BaO)} is preferably set to the above range.

In this embodiment, in the case of glass composition B, the lower limit of {C(BaO)/M(BaO)+C(Li ₂ O)/M(LiO _0.5 )} is preferably 0.15, and more preferably in order 0.16, 0.17, 0.18, 0.19, 0.20. In addition, the upper limit is preferably 0.35, and the more preferable order is 0.34, 0.33, 0.32, 0.31, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23.

In glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, {C(BaO)/M(BaO)+C(Li ₂ O)/M( LiO _0.5 )} is preferably set to the above range.

In this embodiment, when the glass composition is B, {C(Na ₂ O)/M(NaO _0.5 )+C(K ₂ O)/M(KO _0.5 )+C(SiO ₂ )/M(SiO ₂ ) The lower limit of +C(TiO ₂ )/M(TiO ₂ )+C(Nb ₂ O ₅ )/M(NbO _2.5 )+C(WO ₃ )/M(WO ₃ )}, preferably 0.05, more preferable order The sequence is 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16. In addition, the upper limit is preferably 0.30, and the more preferable order is 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21.

In the glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, C(Na ₂ O)/M(NaO _0.5 )+C(K ₂ O)/ M(KO _0.5 )+C(SiO ₂ )/M(SiO ₂ )+C(TiO ₂ )/M(TiO ₂ )+C(Nb ₂ O ₅ )/M(NbO _2.5 )+C(WO ₃ )/ M(WO ₃ )} is preferably set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the mass ratio [C(BaO)/{C(SiO ₂ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ The lower limit of )}] is preferably 1.0, and the more preferable order is 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4. In addition, the upper limit of the mass ratio is preferably 5.5, and the more preferable order is 5.3, 5.1, 4.9, 4.7, 4.5, 4.3, 4.1, 3.9, 3.7, 3.5.

In glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, and the viewpoint of reducing the temperature coefficient (dn/dT) of the relative refractive index, it is best to compare the mass [C(BaO)/{C(SiO ₂ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )}] is set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the mass ratio [C(BaO)/{C(SiO ₂ )+C(B ₂ O ₃ )+C(TiO ₂ )+C(Nb ₂ The lower limit of O ₅ )+C(WO ₃ )}] is preferably 0.80, more preferably 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20 in order. In addition, the upper limit of the mass ratio is preferably 1.70, and the more preferable order is 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35 in order.

In the glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, and a viewpoint of lowering the temperature dependence of the temperature coefficient (dn/dT) of the relative refractive index, the most It is better to set the mass ratio [C(BaO)/{C(SiO ₂ )+C(B ₂ O ₃ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )}] to the above range .

In the glass material for molding of this embodiment, when the glass composition is B, the mass ratio [{C(BaO)+C(Li ₂ O)+C(SrO)}/{C(SiO ₂ )+C(TiO ₂ The lower limit of )+C(Nb ₂ O ₅ )+C(WO ₃ )}] is preferably 0.5, and the more preferable order is 1.0, 1.5, 2.0, 2.2, 2.4. In addition, the upper limit of the mass ratio is preferably 7.0, and the more preferable order is 6.5, 6.0, 5.5, 5.0, 4.5, 4.0, 3.5.

In the glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, it is best to set the mass ratio [{C(BaO)+C(Li ₂ O)+C (SrO)}/{C(SiO ₂ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )}] is set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the mass ratio [{C(Li ₂ O)+C(Na ₂ O)+C(K ₂ O)+C(Cs ₂ O)+C The lower limit of (CaO)+C(SrO)+C(BaO)}/{C(SiO ₂ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )}], preferably 0.5 , The better order is 1.0, 1.5, 2.0, 2.2, 2.4. In addition, the upper limit of the mass ratio is preferably 7.0, and the more preferable order is 6.5, 6.0, 5.5, 5.0, 4.5, 4.0, 3.5.

In the glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, it is best to make the mass ratio [{C(Li ₂ O)+C(Na ₂ O) +C(K ₂ O)+C(Cs ₂ O)+C(CaO)+C(SrO)+C(BaO))/{C(SiO ₂ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )}] is set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the total content is [C(ZnO)+C(Gd ₂ O ₃ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO _{The lower limit of 3} )] is preferably 0, and more preferably the order is 1, 2, 3, 4, and 5 in order. The total content may also be zero. In addition, the upper limit of the total content is preferably 15, and the more preferable order is 14, 13, 12, 11, 10, 9, 8, 7, and 6.

In the glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} and a small dispersion, it is best to set the total content [C(ZnO)+C(Gd ₂ O ₃ )+C(TiO ₂ ) +C(Nb ₂ O ₅ )+C(WO ₃ )] is set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the total content is [C(SiO ₂ )+C(ZnO)+C(Gd ₂ O ₃ )+C(TiO ₂ )+C(Nb ₂ O _{The lower limit of 5} )+C(WO ₃ )] is preferably 5, more preferably 6, 7, 8, 9 in order. In addition, the upper limit of the total content is preferably 25, and more preferably, the order is 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14 in order.

In the glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, it is best to set the total content [C(SiO ₂ )+C(ZnO)+C( Gd ₂ O ₃ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )] is set to the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, the total content is [C(SiO ₂ )+C(ZnO)+C(Gd ₂ O ₃ )+C(ZrO ₂ )+C(TiO ₂ ) The lower limit of +C(Nb ₂ O ₅ )+C(WO ₃ )] is preferably 5, more preferably 6, 7, 8, 9 in order. In addition, the upper limit of the total content is preferably 25, and more preferably, the order is 24, 23, 22, 21, 20, 19, 18, 17, and 16.

In the glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, it is best to set the total content [C(SiO ₂ )+C(ZnO)+C( Gd ₂ O ₃ )+C(ZrO ₂ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )] is set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the total content is [C(Al ₂ O ₃ )+C(SiO ₂ )+C(ZnO)+C(Gd ₂ O ₃ )+C(ZrO ₂ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )] is the lower limit, preferably 5, and more preferably 6, 7, 8, 9 in order. In addition, the upper limit of the total content is preferably 25, and more preferably, the order is 24, 23, 22, 21, 20, 19, 18, 17, and 16.

In the glass composition B, from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L} , high refractive index and low dispersion, it is best to set the total content [C(Al ₂ O ₃ )+C(SiO ₂ ) +C(ZnO)+C(Gd ₂ O ₃ )+C(ZrO ₂ )+C(TiO ₂ )+C(Nb ₂ O ₅ )+C(WO ₃ )] is set to the above range.

In this embodiment, in the case of glass composition B, _{the lower limit of the total content [C(La 2} O ₃ )+C(Gd ₂ O ₃ )+C(Y ₂ O ₃ )] is preferably 25, and more preferably the order Sequence 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38 in sequence. In addition, the upper limit of the total content is preferably 50, and more preferably, 49, 48, 47, 46, 45, 44, and 43 are in order.

In the glass composition B, the total content [C(La ₂ O ₃ )+C(Gd ₂ O ₃ )+C(Y ₂ O ₃ )] is the best in terms of obtaining high refractive index and low dispersion molding glass materials Set to the above range.

In this embodiment, in the case of glass composition B, _{the lower limit of the total content [C(SiO 2} )+C(B ₂ O ₃ )+C(Al ₂ O ₃ )] is preferably 15, and more preferably in order Department 16, 17, 18, 19. In addition, the upper limit of the total content is preferably 30, and more preferably 29, 28, 27, 26, 25 in this order.

In glass composition B, the total content [C(SiO ₂ )+C(B ₂ O ₃ )+C( Al ₂ O ₃ )] is preferably set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the mass ratio is [{C(La ₂ O ₃ )+C(Gd ₂ O ₃ )+C(Y ₂ O ₃ )}/{2×C The lower limit of (SiO ₂ )+C(B ₂ O ₃ )+C(Al ₂ O ₃ )}] is preferably 1.00, and the more preferred order is 1.05, 1.10, 1.15, 1.16, 1.17, 1.18, 1.19, 1.20, 1.21. In addition, the upper limit of the mass ratio is preferably 1.80, and the more preferable order is 1.75, 1.70, 1.65, 1.60, 1.55, 1.54, 1.53, 1.52, 1.51, 1.50.

In glass composition B, from the viewpoint of obtaining high refractive index and low dispersion molding glass materials, the mass ratio [{C(La ₂ O ₃ )+C(Gd ₂ O ₃ )+C(Y ₂ O ₃ )}/ {2×C(SiO ₂ )+C(B ₂ O ₃ )+C(Al ₂ O ₃ )}] is preferably set to the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, the lower limit of the _{total content [2×C(SiO 2} )+C(B ₂ O ₃ )+C(Al ₂ O _{3 )] is preferably} 20. The better order is 21, 22, 23, 24, 25, 26. In addition, the upper limit of the total content is preferably 45, and the more preferable order is 44, 43, 42, 41, 40, 39, 38, 37, 36, 35 in this order.

In glass composition B, the total content is [2×C(SiO ₂ )+C(B ₂ O ₃ )+C from the viewpoint of obtaining _{a glass material for molding with a large average linear expansion coefficient α L, high refractive index and low dispersion.} (Al ₂ O ₃ )] is preferably set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the mass ratio [{C(La ₂ O ₃ )+C(Y ₂ O ₃ )}/{C(B ₂ O ₃ )+C(BaO The lower limit of )}] is preferably 0.50, more preferably 0.55, 0.60, 0.65, 0.70, 0.75, 0.80 in order. In addition, the upper limit of the mass ratio is preferably 1.30, and the more preferable order is 1.25, 1.20, 1.15, 1.10, 1.05, 1.00, 0.95, 0.92.

_{In glass composition B, the mass ratio [{C(La 2} O ₃ )+C(Y ₂ O ₃ )}/{C(B ₂ O ₃ ) from the viewpoint of obtaining high refractive index and low dispersion molding glass materials +C(BaO)}] is preferably set to the above range.

In this embodiment, when the glass composition is B, [C(Gd ₂ O ₃ )/M(GdO _1.5 )+C(ZnO)/M(ZnO)+C(TiO ₂ )/M(TiO ₂ )+C The lower limit of (Nb ₂ O ₅ )/M(NbO _2.5 )+C(WO ₃ )/M(WO ₃ )+C(Bi ₂ O ₃ )/M(BiO _1.5 )] is preferably 0, more preferably the order The order is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06. The value can also be 0. In addition, the upper limit is preferably 0.30, and the more preferable order is 0.25, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, 0.08.

In the glass composition B, from the viewpoint that the average linear expansion coefficient α _{L is} large and the decrease in the thermal stability of the glass is suppressed, [C(Gd ₂ O ₃ )/M(GdO _1.5 )+C(ZnO)/M(ZnO)+C (TiO ₂ )/M(TiO ₂ )+C(Nb ₂ O ₅ )/M(NbO _2.5 )+C(WO ₃ )/M(WO ₃ )+C(Bi ₂ O ₃ )/M(BiO _1.5 ) ] It is better to set the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the mass ratio [C(Y ₂ O ₃ )/{C(La ₂ O ₃ )+C(Y ₂ O ₃ )+C(Gd ₂ O ₃ )}], the lower limit is preferably 0.20, more preferably 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34 in order. In addition, the upper limit of the mass ratio is preferably 0.60, and the more preferable order is 0.59, 0.58, 0.57, 0.56, 0.55, 0.54, 0.53, 0.52, 0.51, 0.50, 0.49, 0.48, 0.47, 0.46.

In the glass composition B, from the viewpoint that the average linear expansion coefficient α _{L is} large and the decrease in the thermal stability of the glass is suppressed, the mass ratio [C(Y ₂ O ₃ )/{C(La ₂ O ₃ )+C(Y ₂ O ₃ )+C(Gd ₂ O ₃ )}] is set to the above range.

In the glass material for molding of this embodiment, when the glass composition is B, the mass ratio is [C(Y ₂ O ₃ )/{C(La ₂ O ₃ )+C(Y ₂ O ₃ )+C(TiO ₂ ) The lower limit of }] is preferably 0.20, more preferably 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32 in order. In addition, the upper limit of the mass ratio is preferably 0.50, and the more preferable order is 0.49, 0.48, 0.47, 0.46, 0.45.

In the glass composition B, from the viewpoint that the average linear expansion coefficient α _{L is} large and the decrease in the thermal stability of the glass is suppressed, the mass ratio [C(Y ₂ O ₃ )/{C(La ₂ O ₃ )+C(Y ₂ O ₃ )+C(TiO ₂ )}] is set to the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, _{the lower limit of the total content [C(BaO)+C(La 2} O ₃ )+C(Y ₂ O ₃ )] is preferably 50, more The best order is 52, 54, 56, 58, 60, 62, 64, 66, 68, 70. In addition, the upper limit of the total content is preferably 85, and more preferably 83, 81, 79, 77, and 76 in this order.

In the glass composition B, from the viewpoint of obtaining _{a molding glass material that suppresses the decrease in the average linear expansion coefficient α L} , and has a high refractive index and low dispersion, it is best to set the total content [C(BaO)+C(La ₂ O ₃ )+ C(Y ₂ O ₃ )] is set to the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, _{the lower limit of the SiO 2} content is preferably 3.0%, and the more preferable order is 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0 %, 6.5%, 7.0%. In addition, the _{upper limit of the SiO 2} content is preferably 15.0%, and the more preferable order is 14.5%, 14.0%, 13.5%, 13.0%, 12.5%, 12.0%, 11.5%, 11.0%, 10.5%, 10.0%.

In the glass composition B, SiO ₂ is a network forming component of glass, and has the functions of improving the thermal stability, chemical durability, and weather resistance of the glass, increasing the viscosity of the molten glass, and facilitating the molding of the molten glass. In addition, SiO ₂ has a stronger effect of increasing the ΔPg and F values than _{La 2} O ₃ , BaO, and Y ₂ O ₃ contained in a large amount in the glass composition B, for example. On the other hand, if the SiO ₂ content is too high, the average linear expansion coefficient α _{L is} more likely to be lowered, and there is a concern that the refractive index nd may be lowered. In addition, if the SiO ₂ content is too small, the stability during reheating may deteriorate. Therefore, the _{content of SiO 2 is} preferably within the above range.

In the molding glass material of the present embodiment, when the glass composition is B, _{the lower limit of the B 2} O ₃ content is preferably 8.0%, and the more preferable order is 8.5%, 9.0%, 9.5%, 10.0%, 10.5% , 11.0%, 11.5%, 12.0%. In addition, the _{upper limit of the B 2} O ₃ content is preferably 20.0%, and the more preferable order is 19.5%, 19.0%, 18.5%, 18.0%, 17.5%, 17.0%, 16.5%, 16.0%, 15.5%, 15.0%.

In the glass composition B, B ₂ O ₃ is a network forming component of the glass, and has the effect of improving the thermal stability of the glass. In addition, it is a component that does not lower the average linear expansion coefficient α _L among the network forming components. In addition, from the viewpoint of obtaining high refractive index nd glass without impairing damage and having low dispersibility, the B ₂ O ₃ content may be set within the above-mentioned range. On the other hand, if the B ₂ O ₃ content is too large, the refractive index nd may decrease. In addition, if the B ₂ O ₃ content is too small, the stability during reheating may deteriorate.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of the Al 2} O ₃ content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5%, 0.2%, 0.1%. In addition, _{the lower limit of the Al 2} O ₃ content is preferably 0%. The _{content of Al 2} O ₃ may also be 0%.

In the glass composition B, Al ₂ O ₃ is a glass component that has the effect of improving the chemical durability and weather resistance of the glass, and it can also be considered as a network forming component. On the other hand, if the _{content of Al 2} O _{3 is} too high, the refractive index nd may decrease, and the thermal stability and meltability of the glass may decrease. Therefore, the _{content of Al 2} O _{3 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of the P 2} O ₅ content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5%, 0.2%, 0.1%. In addition, the lower limit of the content of _{P 2} O _{5 is preferably 0%.} The _{content of P 2} O ₅ may also be 0%.

In the glass composition B, P ₂ O _{5 is} a component that lowers the refractive index nd, and it is also a component that lowers the thermal stability of the glass. Therefore, the _{content of P 2} O _{5 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of Li 2} O content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5 %, 0.2%, 0.1%. In addition, _{the lower limit of the Li 2} O content is preferably 0%. The _{content of Li 2} O may also be 0%.

In the glass composition B, Li ₂ O is a component that contributes to the lowering of the specific gravity of the glass, and has the effect of improving the meltability of the glass and increasing the average linear expansion coefficient α _L. In addition, it is a component that contributes to lowering the glass transition temperature Tg, and contributes to the improvement of moldability when precision press molding is performed. In addition, from the viewpoint of obtaining a glass with a high refractive index nd without impairing and low dispersibility, the _{content of Li 2} O may be set within the above-mentioned range. On the other hand, if the _{content of Li 2} O is too high, the devitrification resistance and acid resistance may decrease. In addition, there is a concern that low dispersion may be compromised.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of Na 2} O content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5 %, 0.2%, 0.1%. In addition, _{the lower limit of the Na 2} O content is preferably 0%. The Na ₂ O content can also be 0%.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of K 2} O content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5 %, 0.2%, 0.1%. In addition, _{the lower limit of the K 2} O content is preferably 0%. The K ₂ O content can also be 0%.

In the glass material for molding of this embodiment, in the case of glass composition B, _{the upper limit of the total content of Na 2} O and K ₂ O is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2 %, 1%, 0.5%, 0.2%, 0.1%. In addition, the lower limit of the total content is preferably 0%, and more preferably, the order is 0.001%, 0.01%, and 0.05% in this order.

In the glass composition B, both Na ₂ O and K ₂ O have the function of improving the glass meltability. In addition, it has the effect of increasing the average linear thermal expansion coefficient. On the other hand, if these contents are too high, thermal stability, devitrification resistance, chemical durability, and weather resistance will decrease. Therefore, _{the respective contents and total contents of Na 2} O and K ₂ O are preferably within the above-mentioned range.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of Cs 2} O content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5 %, 0.2%, 0.1%. In addition, _{the lower limit of the Cs 2} O content is preferably 0%. The _{content of Cs 2} O can also be 0%.

In the glass composition B, Cs ₂ O has the effect of improving the melting of the glass, but if the content is too large, it will reduce the thermal stability and refractive index nd of the glass, and increase the volatilization of the glass component during the melting, resulting in the inability to obtain the glass. Need glass concerns. Therefore, the _{content of Cs 2} O is preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, _{the upper limit of the total content of Li 2} O, Na ₂ O, K ₂ O, and Cs ₂ O is preferably 10%, and more preferably 8% in order. , 6%, 4%, 2%, 1%, 0.5%, 0.2%, 0.1%. In addition, the lower limit of the total content is preferably 0%. The total content may also be 0%. From the viewpoint of suppressing the rise in the liquidus temperature of the glass, the _{total content of Li 2} O, Na ₂ O, K ₂ O, and Cs ₂ O is preferably within the above-mentioned range.

In the glass material for molding of this embodiment, in the case of glass composition B, the upper limit of MgO content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5%, 0.2%, 0.1%. In addition, the lower limit of the MgO content is preferably 0%. The MgO content can also be 0%.

In the glass material for molding of this embodiment, in the case of glass composition B, the upper limit of the CaO content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5%, 0.2%, 0.1%. In addition, the lower limit of the CaO content is preferably 0%. The content of CaO may also be 0%.

In the molding glass material of this embodiment, when the glass composition is B, the upper limit of the SrO content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5%, 0.4%, 0.3%. In addition, the lower limit of the SrO content is preferably 0%, and the more preferable order is 0.05%, 0.10%, 0.15%, 0.20%.

In the glass material for molding of this embodiment, in the case of glass composition B, the upper limit of the total content of MgO, CaO, and SrO is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%. , 1%, 0.5%, 0.4%, 0.3%. In addition, the lower limit of the total content is preferably 0%, and more preferably, the order is 0.05%, 0.10%, 0.15%, 0.20%. The total content may also be 0%.

In the glass composition B, MgO, CaO, and SrO are all glass components that have the effect of improving glass meltability, and also have the effect of increasing the average linear expansion coefficient. However, if the content of these glass components is too large, the thermal stability and devitrification resistance of the glass will decrease. Therefore, each content and total content of the glass components are preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, the lower limit of the BaO content is preferably 20%, and the more preferable order is 21%, 22%, 23%, 24%, 25%, 26%. , 27%, 28%, 29%, 30%, 31%. In addition, the upper limit of the BaO content is preferably 45%, and the more preferable order is 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, 34%.

In the glass composition B, BaO is a glass component that does not impair the high refractive index and low dispersion characteristics and increases the average linear expansion coefficient α _L. It is also a component that reduces the ΔPg and F values. By setting the BaO content in the above range, a glass material for molding with a high refractive index, a low dispersion, and an _{improved average linear expansion coefficient α L can be obtained.} On the other hand, if the content of BaO is too large, the thermal stability of the glass may decrease, the glass may lose clarity, and the stability at the time of reheating may deteriorate.

In the glass material for molding of this embodiment, in the case of glass composition B, _{the upper limit of the total content of SiO 2} and B ₂ O _{3 is} preferably 30%, and the more preferable order is 29%, 28%, 27%, 26 %, 25%, 24%, 23%, 22%, 21%, 20%. In addition, the lower limit of the total content is preferably 13%, and a more preferable order is 14%, 15%, 16%, 17%, 18%.

_{In the glass composition B, the total content of SiO 2} and B ₂ O _{3 is} preferably set to the above range from the viewpoint of maintaining glass stability and suppressing the decrease in refractive index.

In the glass material for molding of this embodiment, in the case of glass composition B, the upper limit of the mass ratio [BaO/(SiO ₂ +B ₂ O ₃ )] of the _{BaO content and the total content of SiO 2} and B ₂ O _{3 is preferable} The order is 3.00, and the better order is 2.80, 2.60, 2.40, 2.20, 2.00, 1.80, 1.70. In addition, the lower limit of the mass ratio is preferably 0.60, and the more preferable order is 0.80, 0.90, 1.00, 1.10, 1.20, and 1.30.

In the glass composition B, from the viewpoint of obtaining a glass that maintains the stability _{of the glass and has a large average linear expansion coefficient α L} , the mass ratio is preferably set to the above-mentioned range.

In the glass material for molding of this embodiment, in the case of glass composition B, the upper limit of ZnO content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.05%, 0.03%, 0.02%, 0.01%. In addition, the lower limit of the ZnO content is preferably 0%. The ZnO content can also be 0%.

In the glass composition B, ZnO is a glass component that has the function of improving glass melting. However, if the ZnO content is too large, the specific gravity of the glass may increase and the average linear expansion coefficient α _{L may} decrease. In addition, there is also a concern that the low dispersion of the glass may be impaired. In addition, there is also a concern that the glass transition temperature Tg may decrease. Therefore, the ZnO content is preferably within the above range.

In the molding glass material of this embodiment, when the glass composition is B, _{the lower limit of the La 2} O ₃ content is preferably 15%, and the more preferable order is 16%, 17%, 18%, 19%, 20%. , 21%, 22%. In addition, the _{upper limit of La 2} O ₃ content is preferably 40%, and the more preferable order is 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31%, 30%, 29%, 28%.

In the glass composition B, La ₂ O ₃ is a glass component that has the effect of suppressing the decrease in the Abbe number νd and increasing the refractive index. In addition, it is a component that lowers the partial dispersion ratio Pg and F, and the effect of lowering the ΔPg and F value is stronger than that of BaO. Therefore, by setting the _{content of La 2} O ₃ within the above range, a molding application with high refractive index, low dispersion, suppression of a decrease in the average linear expansion coefficient α _L , and suppression of an increase in the temperature coefficient of the relative refractive index (dn/dT) can be obtained. Glass material. On the other hand, if the La ₂ O ₃ content is excessively increased, the thermal stability and devitrification resistance of the glass may decrease, and the stability during reheating may also deteriorate.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of the Gd 2} O ₃ content is preferably 20%, and the more preferable order is 15%, 10%, 5%, 4%, 3%, 2%, 1%, 0.5%. In addition, the lower limit of the content of _{Gd 2} O _{3 is preferably 0%.} The _{content of Gd 2} O ₃ may also be 0%.

In the glass composition B, Gd ₂ O ₃ is a component that has high refraction and low dispersion and can suppress the _{decrease in the average linear expansion coefficient α L.} However, in the glass of this embodiment in which a large amount of BaO is introduced, if the Gd ₂ O ₃ content is excessively increased, It will lead to a decrease in the thermal stability and resistance to devitrification of the glass, and it will easily lead to devitrification of the glass during manufacturing. In addition, if the Gd ₂ O ₃ content is excessively increased, the specific gravity of the glass will increase, so it is best not to. In addition, it is also disadvantageous from the viewpoint of reducing the cost of raw materials. Therefore, the _{content of Gd 2} O _{3 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, _{the lower limit of the Y 2} O ₃ content is preferably 5%, and the more preferable order is 6%, 7%, 8%, 9%, 10%. , 11%, 12%, 13%, 14%. In addition, the _{upper limit of the Y 2} O ₃ content is preferably 25%, and the more preferable order is 24%, 23%, 22%, 21%, 20%, 19%.

In the glass composition B, Y ₂ O ₃ is a component that has the effect of suppressing the decrease in the Abbe number νd and increasing the refractive index. In addition, the glass of the present embodiment in which a large amount of BaO or SrO is introduced into the alkali component or alkaline earth component is also _{an effective component for suppressing the decrease in the average linear expansion coefficient α L} and imparting high refractive index and low dispersion characteristics. In addition, it also has the effect of improving the chemical durability and weather resistance of the glass, and increasing the glass transition temperature. The component that reduces the partial dispersion ratio Pg, F also has the effect of reducing the value of ΔPg, F. On the other hand, if the Y ₂ O ₃ content is excessively increased, the thermal stability and devitrification resistance of the glass may decrease. There is also a concern that the stability during reheating may deteriorate. Therefore, the _{content of Y 2} O _{3 is} preferably within the above range.

In the molding glass material of this embodiment, when the glass composition is B, the _{upper limit of the ZrO 2} content is preferably 10%, and the more preferable order is 9%, 8%, 7%, 6%, 5%, 4%. , 3%, 2.5%. In addition, _{the lower limit of the ZrO 2} content is preferably 0%, and the more preferable order is 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1.0%, 1.5%, 2.0%. The ZrO ₂ content can also be 0%.

In the glass composition B, ZrO ₂ is a component that has the effect of increasing the refractive index. By containing it in an appropriate amount, it also has the effect of improving the thermal stability of the glass. However, ZrO ₂ is not only a component that makes the average linear expansion coefficient α _L smaller, but also a component that increases the temperature dependence of the temperature coefficient of the relative refractive index (dn/dT). In addition, if the content is too large, the thermal stability may be significantly reduced. Therefore, the _{content of ZrO 2 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of TiO 2} content is preferably 15%, and the more preferable order is 14%, 13%, 12%, 11%, 10%, 9%. , 8%, 7%, 6%. In addition, _{the lower limit of the TiO 2} content is preferably 0%, and the more preferable order is 1%, 2%, 3%, 4%, 5%. The TiO ₂ content can also be 0%.

In the glass composition B, TiO ₂ is a component that has the effect of increasing the refractive index. By containing it in an appropriate amount, it also has the effect of improving the thermal stability of the glass. TiO ₂ is a component that increases the partial dispersion ratio of Pg, F, and the effect of increasing the value of Pg, F and ΔPg, F is stronger than that of Nb ₂ O ₅ . On the other hand, if the _{content of TiO 2 is} too large, in addition to the possibility of a _{decrease in the average linear expansion coefficient α L} , there is also a possibility of a decrease in the Abbe number νd, and there is a possibility of increased coloring of the glass and deterioration of the meltability. consider. There is also a concern that the stability during reheating may deteriorate. Therefore, the _{content of TiO 2 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of the Nb 2} O ₅ content is preferably 20%, and the more preferable order is 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 5%, 3%, 2%, 1%. In addition, _{the lower limit of the Nb 2} O ₅ content is preferably 0%, and a more preferable order is 0.001%, 0.003%, 0.005%, 0.010%, 0.050%, 0.080%, 0.100%. The Nb ₂ O ₅ content can also be 0%.

In the glass composition B, Nb ₂ O ₅ is a component that has the effect of increasing the refractive index. By containing it in an appropriate amount, it also has the effect of improving the thermal stability of the glass. In addition, Nb ₂ O ₅ is a component that increases the partial dispersion ratios Pg,F and ΔPg,F. On the other hand, if the _{content of Nb 2} O _{5 is} too large, in addition to the possibility of lowering the average linear expansion coefficient α _L , there is also the possibility of increased coloring of the glass. There is also a concern that the stability during reheating may deteriorate. Therefore, the Nb ₂ O ₅ content is preferably within the above range.

In the molding glass material of this embodiment, when the glass composition is B, the _{upper limit of WO 3} content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5%. , 0.1%. In addition, _{the lower limit of the WO 3} content is preferably 0%. The WO ₃ content can also be 0%.

In the glass composition B, WO ₃ has the effect of reducing the glass transition temperature Tg for other high-dispersion components. Therefore, when the glass is subjected to softening molding, especially when precision stamping is performed, it can be used to protect the molding die, protective film, and molding. The machine is introduced for the purpose of lowering the molding temperature. On the other hand, from the viewpoint of increasing the glass transmittance and suppressing the increase in the temperature coefficient (dn/dT) of the relative refractive index of the glass, the WO ₃ content is preferably within the above-mentioned range.

In the glass material for molding of this embodiment, when the glass composition is B, the _{upper limit of the Bi 2} O ₃ content is preferably 10%, and the more preferable order is 8%, 6%, 4%, 2%, 1%, 0.5%, 0.1%. In addition, _{the lower limit of the Bi 2} O ₃ content is preferably 0%. The _{content of Bi 2} O ₃ may also be 0%.

In the glass composition B, Bi ₂ O ₃ is a component that increases the refractive index nd and decreases the Abbe number νd. In addition, it is also a component that easily enhances the coloring of the glass. Therefore, the _{content of Bi 2} O _{3 is} preferably within the above range.

In the glass material for molding of this embodiment, in the case of glass composition B, the _{upper limit of Ta 2} O ₅ content is preferably 20%, and the more preferable order is 15%, 13%, 10%, 5%, 3%, 1%. In addition, the lower limit of the content of _{Ta 2} O _{5 is preferably 0%.} The _{content of Ta 2} O ₅ may also be 0%.

In the glass composition B, Ta ₂ O ₅ is a glass component that improves the thermal stability and devitrification resistance of glass. On the other hand, Ta ₂ O ₅ increases the refractive index and makes the glass highly dispersed. In addition, if the _{content of Ta 2} O _{5 is} too high, the thermal stability of the glass is reduced, and when the glass is melted, the melting residue of the glass raw material is likely to occur. In addition, it is a component that lowers the average linear expansion coefficient α _L. Therefore, the _{content of Ta 2} O ₅ should preferably be within the above range. In addition, _{compared to other glass components, Ta 2} O ₅ is a very high unit price component. If the _{content of Ta 2} O _{5 is} too high, it will cause glass damage. Increased production costs. In addition, since _{the molecular weight of Ta 2} O ₅ is larger than that of other glass components, the specific gravity of the glass increases, and as a result, the weight of the optical element increases.

In the glass material for molding of the present embodiment, in the case of the glass composition B, the _{upper limit of the Sc 2} O ₃ content is preferably 2%. In addition, the lower limit of the content of _{Sc 2} O _{3 is preferably 0%.}

In the glass material for molding of this embodiment, in the case of the glass composition B, the _{upper limit of the HfO 2} content is preferably 2%. In addition, _{the lower limit of the HfO 2} content is preferably 0%.

In the glass composition B, both Sc ₂ O ₃ and HfO ₂ are components that have the effect of increasing the refractive index nd and have a high unit price. Therefore, _{the contents of Sc 2} O ₃ and HfO ₂ are preferably within the above-mentioned range.

In the glass material for molding of the present embodiment, when the glass composition is B, the _{upper limit of the Lu 2} O ₃ content is preferably 2%. In addition, the lower limit of the content of _{Lu 2} O _{3 is preferably 0%.}

In the glass composition B, Lu ₂ O ₃ has the effect of increasing the refractive index nd. In addition, since the molecular weight is large, it is also a glass component that increases the specific gravity of glass. Therefore, the _{content of Lu 2} O _{3 is} preferably within the above range.

In the glass material for molding of the present embodiment, in the case of glass composition B, the _{upper limit of the GeO 2} content is preferably 2%. In addition, _{the lower limit of the GeO 2} content is preferably 0%.

In the glass composition B, GeO ₂ has the effect of increasing the refractive index nd, and is a component with a very high unit price among the glass components generally used. Therefore, from the viewpoint of reducing glass manufacturing costs, the GeO ₂ content is preferably within the above-mentioned range.

In the glass material for molding of the present embodiment, when the glass composition is B, the _{upper limit of the La 2} O ₃ content is preferably 2%. In addition, _{the lower limit of the La 2} O ₃ content is preferably 0%. The _{content of La 2} O ₃ may also be 0%.

In the glass composition B, if the La ₂ O ₃ content is too large, the thermal stability and devitrification resistance of the glass will decrease, and the devitrification of the glass is likely to occur during manufacture. Therefore, from the viewpoint of suppressing the decrease in thermal stability and devitrification resistance, the La ₂ O ₃ content is preferably within the above-mentioned range.

In the glass material for molding of the present embodiment, in the case of glass composition B, the _{upper limit of the Yb 2} O ₃ content is preferably 2%. In addition, _{the lower limit of the Yb 2} O ₃ content is preferably 0%.

In the glass composition B, if the _{content of Yb 2} O _{3 is} too large, the thermal stability and devitrification resistance of the glass may decrease. Moreover, among the glass components generally used, it is a high-priced component. From the viewpoint of preventing the thermal stability of the glass from decreasing, suppressing the increase in specific gravity, and suppressing the glass manufacturing cost, the Yb ₂ O ₃ content is preferably within the above-mentioned range.

In the case of the glass composition B of the glass material for molding of the present embodiment, it is preferable to mainly consist of the above-mentioned glass components SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , P ₂ O ₅ , Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O, MgO, CaO, SrO, BaO, ZnO, La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , Ta ₂ O ₅ , Sc ₂ O ₃ , HfO ₂ , Lu ₂ O ₃ , GeO ₂ , and Yb ₂ O ₃ , and the total content of the above glass components is preferably 95% or more, more preferably 98% or more , Over 99% of the best line, over 99.5% of the best line.

In the glass material for molding of this embodiment, the _{upper limit of the TeO 2} content is preferably 2%. In addition, _{the lower limit of the TeO 2} content is preferably 0%.

Because TeO ₂ is toxic, it is best to reduce the content of _{TeO 2.} Therefore, the TeO ₂ content is preferably within the above range.

In the glass material for molding of the present embodiment, in the case of glass composition B, the content of fluorine F is preferably 3% or less, and the upper limit is 1%, 0.5%, and 0.3%. The smaller the F content, the better, and the lower limit is preferably 0%. The F content can also be 0%. In addition, it is preferable that fluorine F is not substantially contained.

In the glass composition B, by setting the F content in the above-mentioned range, the volatilization of the glass during melting can be suppressed, and the fluctuation of the refractive index and the texture can be suppressed.

In addition, it is preferable that the glass material for molding of the present embodiment is basically composed of the above-mentioned glass components, but it may contain other components within a range that does not impair the effects of the present invention. In addition, the present invention does not exclude the inclusion of unavoidable impurities.

＜Other component composition＞ Pb, As, Cd, Tl, Be, and Se are all toxic. Therefore, it is preferable that the glass component of the glass material for molding of the present embodiment does not contain these elements.

U, Th, and Ra are all radioactive elements. Therefore, it is preferable that the glass component of the glass material for molding of the present embodiment does not contain these elements.

V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm series will cause the color of the glass to increase and become the source of fluorescence. Therefore, it is preferable that the glass component of the glass material for molding of the present embodiment does not contain these elements.

Sb(Sb ₂ O ₃ ) and Ce(CeO ₂ ) are arbitrarily addable elements with clarifying agent function. Among them, Sb (Sb ₂ O ₃ ) is a clarifying agent with a greater clarification effect.

The Sb ₂ O ₃ content is expressed as an additional ratio. That is, when the _{total content of all glass components other than Sb 2} O ₃ and CeO ₂ is 100% by mass, the Sb ₂ O ₃ content is preferably less than 1% by mass, more preferably less than 0.1% by mass. In addition, it is particularly preferred that the order is less than 0.05% by mass, less than 0.03% by mass, less than 0.02% by mass, and less than 0.01%. The Sb ₂ O ₃ content may also be 0% by mass.

The CeO ₂ content is also expressed as an additional ratio. That is, when the _{total content of all glass components except CeO 2} and Sb ₂ O ₃ is set to 100% by mass, the CeO ₂ content is preferably less than 2% by mass, more preferably less than 1% by mass, and particularly preferably less than 1% by mass. The range is 0.5% by mass and the best system is less than 0.1% by mass. The CeO ₂ content may also be 0% by mass. By setting the CeO ₂ content in the above range, the clarity of the glass can be improved.

(Glass characteristics with glass composition B) ＜Refractive index nd＞ In the glass material for molding of the present embodiment, in the case of glass composition B, the refractive index nd is not particularly limited, and examples include 1.60 to 2.10, preferably 1.65 to 2.00, more preferably 1.70 to 1.88, and more preferably 1.73 ~1.85. The lower limit of the refractive index nd may also be 1.65, 1.74, 1.75, 1.76, 1.77, 1.78, or 1.79, and the upper limit of the refractive index nd may also be 2.0, 1.9, 1.84, 1.83, or 1.82.

The refractive index nd can become a desired value by appropriately adjusting the content of each glass component in the glass composition B. The components with the effect of relatively increasing the refractive index nd (high refractive index components), such as: Nb ⁵⁺ , Ti ⁴⁺ , W ⁶⁺ , Bi ³⁺ , Ta ⁵⁺ , Zr ⁴⁺ , La ³⁺ _3, etc. _{(That is, Nb 2} O ₅ , TiO ₂ , WO ₃ , Bi ₂ O ₃ , Ta ₂ O ₅ , ZrO ₂ , La ₂ O _3, etc., if expressed in terms of oxides). On the other hand, the components that have the effect of relatively lowering the refractive index nd (low refractive index components) are such as: P ⁵⁺ , Si ⁴⁺ , B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ etc. (that is, if According to the oxide, it is P ₂ O ₅ , SiO ₂ , B ₂ O ₃ , Li ₂ O, Na ₂ O, K ₂ O, etc.).

＜Abbe value νd＞ In the glass material for molding of this embodiment, in the case of glass composition B, the Abbe value νd system can be exemplified as: 20 to 70, preferably 25 to 65, more preferably 30 to 60, and particularly preferably 35 to 55 . The lower limit of Abbe number νd can be 23, 28, 32, 36, 37, 38, 39, or 40, and the upper limit of Abbe number νd can also be 67, 63, 57, 53, 51, 49, 47, 45 , 43, or 42.

The Abbe value νd can be set to a desired value by appropriately adjusting the content of each glass component in the glass composition B. The components that relatively reduce the Abbe number νd (ie, highly dispersed components) can be, for example, Nb ⁵⁺ , Ti ⁴⁺ , W ⁶⁺ , Bi ³⁺ , Ta ⁵⁺ , Zr ^4+, etc. (that is, if oxidized The material representation is Nb ₂ O ₅ , TiO ₂ , WO ₃ , Bi ₂ O ₃ , Ta ₂ O ₅ , ZrO _2, etc.). On the other hand, the components that relatively increase the Abbe number νd (ie, low-dispersion components) can be, for example: P ⁵⁺ , Si ⁴⁺ , B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , La ³⁺ , Ba ²⁺ , Ca ²⁺ , Sr ^2+, etc. (that is, P ₂ O ₅ , SiO ₂ , B ₂ O ₃ , Li ₂ O, Na ₂ O, K ₂ O, La ₂ O ₃ , BaO, CaO, SrO, etc.).

In the glass material for molding of the present embodiment, when the glass composition is B, the refractive index nd and Abbe number νd preferably satisfy the following formula (1), preferably satisfy the following formula (2), and more preferably satisfy the following formula Formula (3), the special best system satisfies the following formula (4). When the refractive index nd and Abbe number νd satisfy the following formula, a glass material for molding with high refractive index and low dispersion characteristics can be obtained. nd-(-0.0183×Abbe value νd+2.502)≧0 …(1) nd-(-0.0183×Abbe value νd+2.512)≧0 …(2) nd-(-0.0183×Abbe value νd+2.522)≧0 …(3) nd-(-0.0183×Abbe value νd+2.532)≧0 …(4)

<Average linear expansion coefficient α _L > In the glass material for molding of this embodiment, in the case of glass composition B, the lower limit of the _{average linear expansion coefficient α L} ^{at -30 to 70°C is preferably 0.80×10 -5} ℃ ^-1 , The better order is 0.81×10 ^-5 ℃ ^-1 , 0.82×10 ^-5 ℃ ^-1 , 0.83×10 ^-5 ℃ ^-1 , 0.84×10 ^-5 ℃ ^-1 , 0.85×10 ^-5 ℃ ^{- 1.} 0.86×10 ^-5 ℃ ^-1 , 0.87×10 ^-5 ℃ ^-1 , 0.88×10 ^-5 ℃ ^-1 . In addition, the upper limit of the average linear expansion coefficient α _L ^{can be exemplified as 1.20×10 -5} ℃ ^-1 , preferably 1.10×10 ^-5 ℃ ^-1 from the viewpoint of maintaining the stability of the glass and obtaining the required optical properties. Below, the more preferable order is 1.00×10 ^-5 ℃ ^-1 , 0.98×10 ^-5 ℃ ^-1 , 0.96×10 ^-5 ℃ ^-1 , 0.95×10 ^-5 ℃ ^-1 , 0.94×10 ^-5 ℃ ^-1 , 0.93×10 ^-5 ℃ ^-1 .

In the case of glass composition B, by setting the average linear expansion coefficient α _{L from} -30 to 70°C in the above range, a molding glass material that can be used in a wide temperature environment can be obtained.

The average linear expansion coefficient α _L is measured in accordance with the regulations of JOGIS16. The sample system is a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. In a state where a load of 98 mN is applied to the sample, the sample is heated at a constant rate of 4°C per minute, and the temperature and sample elongation are measured every 1 second. The average linear expansion coefficient α _L is the average value of the linear expansion coefficient at -30~70℃.

In addition, JOGIS16 stipulates that "the average linear expansion coefficient is ^{expressed in units of 10 -7} ℃ ^-1 to the first place of the integer", but the average linear expansion coefficient α _{L in} this manual is based on [10 ^-5 ·℃ ^-1 ] Unit representation.

In this manual, the average linear expansion coefficient α _L system uses [10 ^-5 ·℃ ^-1 ] as the unit of expression, and even if the unit system uses [10 ^-5 ·K ^-1 ], the average linear expansion coefficient α _L The value of is still the same.

<Average linear expansion coefficient α _100-300 > In the glass material for molding of this embodiment, in the case of glass composition B, _{the lower limit of the average linear expansion coefficient α 100-300} at 100 to 300°C is preferably 90, and more preferable order Order 92, 94, 95 in sequence. In addition, the upper limit of the average linear expansion coefficient α _100-300 , from the viewpoint of maintaining the stability of the glass and obtaining the required optical properties, can be exemplified as 130, preferably 115, and more preferably 110, 106, 104 in order. .

The average linear expansion coefficient α _100-300 is measured in accordance with the regulations of JOGIS08. The sample system is a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. In a state where a load of 98 mN is applied to the sample, the sample is heated at a constant rate of 4°C per minute, and the temperature and sample elongation are measured every 1 second. The average linear expansion coefficient α _100-300 is the average value of the linear expansion coefficient at 100~300℃.

In addition, in this specification, the average linear expansion coefficient α _100-300 is in accordance with the regulations of JOGIS08, ^{expressed in the unit of 10 -7} ℃ ^-1 to the first place of the integer. In other words, the average linear expansion coefficient α _100-300 is set in the unit of [10 ^-7 ·°C ^-1 ] and expressed as an integer.

＜The temperature coefficient of relative refractive index dn/dT＞ The temperature coefficient of glass relative refractive index (dn/dT) is based on Japanese Industrial Standards JISB7072-2 (Method for Measuring the Temperature Coefficient of Refractive Index of Optical Glass-Part 2: Interference Method) , For light with a wavelength of 632.8nm, when the temperature is changed from -40°C to 110°C, the temperature coefficient value of the relative refractive index is measured. In addition, in this manual, the relative refractive index temperature coefficient (dn/dT) is ^{expressed in the unit of [10 -6} ·℃ ^-1 ], even if the unit is [10 ^-6 ·K ^-1 ], the relative refraction The temperature coefficient dn/dT value of the rate remains the same.

In the glass material for molding of this embodiment, in the case of glass composition B, the upper limit of the temperature coefficient dn/dT of the relative refractive index is within the range of He-Ne laser wavelength (633nm to 632.8nm) and temperature 20-40℃ , preferably based 2.0 × 10 ^-6 ℃ ^-1, more preferably sequential order based ^{1.5 × 10 -6 ℃ -1, 1.0} × 10 -6 ℃ -1, 0.5 × 10 -6 ℃ -1, 0.0 × 10 - ⁶ ℃ ^-1 , -0.5×10 ^-6 ℃ ^-1 , -1.0×10 ^-6 ℃ ^-1 . In addition, although the lower limit of the temperature coefficient dn/dT of the relative refractive index is not specifically limited, it is preferably -13.0×10 at the He-Ne laser wavelength (633nm to 632.8nm) and the temperature is within the range of 20-40°C. ^-6 ℃ ^-1 , the better order is -10.0×10 ^-6 ℃ ^-1 , -9.0×10 ^-6 ℃ ^-1 , -8.0×10 ^-6 ℃ ^-1 , -7.0×10 ^-6 ℃ ^{- 1.} -6.5×10 ^-6 ℃ ^-1 .

By setting dn/dT in the above range and combining it with an optical element whose dn/dT is a positive value, or an optical element whose dn/dT is a negative value and the lens focal length has a different sign, even if the temperature of the optical element is large In a fluctuating environment, the refractive index fluctuates still smaller, so the required optical characteristics can still be exerted with high precision in a wider temperature range.

On the other hand, when high-energy light, such as laser light, or light having a wavelength equivalent to the glass absorption wavelength, enters the glass, the increase in the temperature of the glass changes depending on the intensity of the light and the irradiation time. In this case, the glass of the present embodiment alone requires a temperature change that reduces the refractive index.

In this case, the upper limit of the temperature coefficient dn/dT of the relative refractive index, if the He-Ne laser wavelength (633nm to 632.8nm) and the temperature range of 20~40℃ are taken as examples, it is preferably 2.0×10 ^-6 ℃ ^-1 , The better order is 1.5×10 ^-6 ℃ ^-1 , 1.0×10 ^-6 ℃ ^-1 , 0.5×10 ^-6 ℃ ^-1 , 0.3×10 ^-6 ℃ ^-1 , 0.1×10 ^-6 ℃ ^-1 . In addition, the lower limit of the temperature coefficient dn/dT of the relative refractive index is preferably -2.0×10 ^-6 ℃ ^-1 , and the more preferable order is -1.5×10 ^-6 ℃ ^-1 , -1.0×10 ^-6 ℃ ^-1 , -0.5×10 ^-6 ℃ ^-1 , -0.3×10 ^-6 ℃ ^-1 , -0.1×10 ^-6 ℃ ^-1 . The temperature coefficient dn/dT of the relative refractive index can also be set to 0.0×10 ^-6 ℃ ^-1 . In addition, the temperature coefficient (dn/dT) value of the relative refractive index of the glass material for molding of the present embodiment can also be appropriately selected from the above-mentioned preferable range according to the description in this specification, according to the laser wavelength used.

＜Measurement method of temperature dependence of temperature coefficient dn/dT of relative refractive index＞ In the case of the glass of the present embodiment, when the glass composition is B, the temperature dependence of the relative refractive index temperature coefficient (dn/dT) is small. The measurement method is as follows.

According to the method described in the Japan Optical Glass Industry Association standard JOGIS18 "Method for Measuring the Temperature Coefficient of Refractive Index of Optical Glass", the measurement is performed by the interference method. Change the temperature from -40°C to 80°C, and measure the dn/dT with a wavelength of 632.8nm at temperatures of -30°C, -10°C, +10°C, +30°C, +50°C, and +70°C (hereinafter referred to as "Dn/dT@632.8"), use the least square method to find the approximate straight line of dn/dT@632.8 value to temperature, set the slope of the straight line to a, and set the intercept at 0℃ to b.

The closer the above-mentioned slope a is to 0, the smaller the change in dn/dT due to temperature, which means that even in different temperature ranges, the change in dn/dT value per temperature change is smaller. That is, the shifting method of the focal length with respect to the unit temperature change of the optical element is not constant regardless of the temperature. Therefore, the position adjustment mechanism of the light receiving element can be simplified, and it is effective as an optical element for obtaining high-precision imaging.

Therefore, in the glass material for molding of the present embodiment, in the case of glass composition B, the range of the above-mentioned slope a value is preferably 10.0×10 ^-9 to -10.0×10 ^-9 , and the more preferable order is 8.0×10 ^-9 ~-8.0×10 ^-9 , 6.0×10 ^-9 ~-6.0×10 ^-9 , 4.0×10 ^-9 ~-4.0×10 ^-9 , 3.0×10 ^-9 ~-3.0×10 ^-9 .

Furthermore, the closer the intercept b is to 0.0×10 ^-6 , the smaller the value of dn/dT@632.8 when the approximate straight line is at 0°C, which means that the absolute value of the dn/dT value is smaller. Therefore, since the focus distance shift amount becomes smaller than the unit temperature change of the individual optical element, it is effective as an optical element for obtaining high-precision imaging.

Therefore, in the glass material for molding of this embodiment, when the glass composition is B, the range of the intercept b value is preferably 3.0×10 ^-6 to -3.0×10 ^-6 , and the more preferable order is 2.0×10 ^-6 ~-2.0×10 ^-6 , 1.0×10 ^-6 ~-1.0×10 ^-6 , 0.5×10 ^-6 ~-0.5×10 ^-6 . In addition, if the value of the slope a is set to a certain value or less (preferably controlled to be near 0), the intercept b does not necessarily have to be zero. The above-mentioned intercept b can also be set close to 0.

＜Glass transition temperature Tg＞ In the glass material for molding of the present embodiment, in the case of glass composition B, the upper limit of the glass transition temperature Tg is preferably 730°C, and more preferably 720°C, 710°C, and 700°C in this order. In addition, the lower limit of the glass transition temperature Tg is preferably 500°C, and more preferably 550°C, 560°C, 570°C, and 580°C in this order.

When the upper limit of the glass transition temperature Tg satisfies the above range, the increase in the molding temperature and annealing temperature of the glass can be suppressed, and the thermal damage to the press molding equipment and annealing equipment can be reduced. In addition, by making the lower limit of the glass transition temperature Tg satisfy the above-mentioned range, the thermal stability of the glass can be maintained satisfactorily while maintaining the required Abbe number and refractive index. In addition, when used as a precision stamping material, good moldability can be obtained.

On the other hand, because the higher the glass transition temperature Tg, the smaller the amount of expansion per unit temperature change tends to be, so there is a tendency to reduce the degree of shape change caused by the thermal expansion per unit temperature change. In addition, if heating is used to raise the temperature of the glass to near Tg or above the strain point, even if the glass is subsequently cooled, there is still a concern that the optical performance will not return to the original state. Therefore, the lower limit of Tg preferably satisfies the above range.

＜Specific gravity of glass＞ In the glass material for molding of the present embodiment, in the case of the glass composition B, the specific gravity is preferably 5.50 or less, and the order is more preferably, 5.00 or less, and 4.80 or less. If the specific gravity of the glass can be reduced, the weight of the lens can be reduced. As a result, it is possible to reduce the power consumption of a camera lens equipped with a lens during autofocus driving.

＜Light penetration of glass＞ The light transmittance of the glass material for molding of this embodiment can be evaluated by the coloring degrees λ5, λ70, and λ80. In the case of glass composition B, for a glass sample with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance is measured in the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance becomes 5% is set to λ5, and the external transmittance is set to 70 The wavelength of% is set to λ70, and the wavelength at which the external transmittance becomes 80% is set to λ80.

In the glass material for molding of the present embodiment, in the case of glass composition B, λ5 is preferably 400 nm or less, 𨊽 preferably 380 nm or less, more preferably 360 nm or less, and particularly preferably 350 nm or less.

In the glass material for molding of this embodiment, in the case of glass composition B, λ70 is preferably 440 nm or less, more preferably 430 nm or less, and more preferably 420 nm or less.

In the glass material for molding of the present embodiment, in the case of glass composition B, λ80 is preferably 510 nm or less, more preferably 500 nm or less, and more preferably 490 nm or less.

By using λ5, λ70, and λ80 as the above-mentioned short-wavelength molding glass material, it is possible to provide an optical element capable of better color reproduction.

(Glass composition C) Next, regarding the case where the glass material for molding of the present embodiment has the glass composition C, the content and ratio of the glass components, and the glass characteristics will be described.

In the glass material for molding of this embodiment, when the glass is composed of C, SiO ₂ is a network-forming component of the glass, which improves the thermal stability, reheating devitrification, chemical durability, and weather resistance of the glass, and improves the melting The viscosity of the glass is a necessary component for the effect of making molten glass easy to shape. From the above point of view, the SiO ₂ content is expressed in terms of mass %, and it is preferably more than the total content of _{B 2} O ₃ and P ₂ O _5. In the case of glass composition C, silicate glass is preferred. In the case of glass composition C, the SiO ₂ content is preferably 8.0% or more, and the more preferable order is 10.00% or more, 11.00% or more, 12.00% or more, 13.00% or more, 14.00% or more, 14.50% or more, 15.00% or more, 15.50% or more, 16.00% or more, 16.50% or more, 16.60% or more. In the glass material for molding of this embodiment, when the glass composition is C, from the viewpoints of enhancing the devitrification resistance of the glass, enhancing the melting property, and improving the partial dispersion characteristics, the SiO ₂ content is preferably 50.00% or less, and more The best order is 45.00% or less, 40.00% or less, 35.00% or less, 30.00% or less, 28.00% or less, 26.00% or less, 25.00% or less, 24.50% or less, 24.00% or less, 23.50% or less, 23.00% or less, 22.75 % Or less, 22.50% or less, 22.00% or less.

In the glass material for molding of this embodiment, when the glass is composed of C, the total content of _{SiO 2} and B ₂ O _{3 (SiO 2} +B ₂ O ₃ ) improves the thermal stability of the glass, lowers the specific gravity, and From the viewpoint of obtaining better optical constants, preferably 10.00% or more, and the more preferable order is 12.00% or more, 14.00% or more, 15.00% or more, 16.00% or more, 17.00% or more, 17.75% or more, 18.00% or more, 18.25 % Or more, 18.50% or more, 18.60% or more, and preferably 35.00% or less, and the more preferable order is 32.00% or less, 30.00% or less, 28.00% or less, 27.00% or less, 26.50% or less, 26.00% or less, 25.50% or less, 25.00% or less, 24.50% or less, 24.40% or less, 24.30% or less.

In the glass material for molding of this embodiment, when the glass is composed of C, although SiO ₂ and B ₂ O ₃ have the effect of improving the thermal stability of the glass, if the _{content of SiO 2 is} too high, the glass meltability will decrease. The tendency. From the above point of view it is, SiO _{2 2} O ₃ with respect to the mass of the total content of SiO ₂ and B ratio _{(SiO 2 / (SiO 2 +} B 2 O 3)), based preferably 0.50 or more, more preferably 0.55 based sequential order Above, 0.60 or above, 0.65 or above, 0.70 or above, 0.75 or above, 0.77 or above, 0.80 or above, more preferably 1.00 or below, and more preferably in order of 0.99 or below, 0.98 or less, 0.97 or less, 0.96 or less, 0.95 or less, 0.94 Below, 0.93 or less, 0.92 or less, 0.91 or less, 0.90 or less, 0.89 or less, 0.88 or less.

In the glass material for molding of this embodiment, in the case of glass composition C, the mass ratio of _{B 2} O ₃ content to SiO _{2 content (B 2} O ₃ /SiO ₂ ) improves chemical durability and reduces α _max , And from the viewpoint of improving reheating devitrification, it is preferably less than 1.00, and the more preferable order is 0.90 or less, 0.80 or less, 0.70 or less, 0.60 or less, 0.50 or less, 0.40 or less, 0.35 or less, 0.32 or less, 0.31 or less in order , 0.30 or less, 0.29 or less, 0.28 or less, 0.27 or less, 0.26 or less, 0.25 or less. From the viewpoint of improving the thermal stability, the mass ratio (B ₂ O ₃ /SiO ₂ ) is preferably 0.00 or more, and the more preferable order is 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.10 or more, 0.11 or more, 0.12 or more, 0.13 or more, 0.14 or more, or 0.15 or more.

In the glass material for molding of the present embodiment, when the glass is composed of C, the _{content of B 2} O _{3 is} preferably 0.00% or more, more preferably more than 0.00%, and particularly preferred order is 0.10% or more, 0.20% or more, 0.30% or more, 0.35% or more, 0.37% or more, 0.39% or more, 0.40% or more, 0.41% or more, 0.42% or more, 0.43% or more, 0.44% or more, 0.45% or more, 0.46% or more, 0.47% or more, 0.48% Above 0.49%. In addition, the B ₂ O ₃ content is preferably 30.00% or less, and the more preferable order is 25.00% or less, 20.00% or less, 18.00% or less, 16.00% or less, 14.00% or less, 12.00% or less, 10.00% or less, 9.00% Or less, 8.00% or less, 7.00% or less, 6.00% or less, 5.50% or less, 5.20% or less, 5.10% or less, 5.00% or less, 4.90% or less, 4.80% or less. By setting the _{content of B 2} O ₃ within the above range, the specific gravity of the glass can be further reduced, and the thermal stability of the glass can be improved.

In the glass material for molding of this embodiment, when the glass is composed of C, the CaO content is preferably 3.00% or more, more preferably 4.00% or more from the viewpoint of improving glass meltability and thermal stability. The sequence is above 5.00%, above 5.10%, above 5.20%, above 5.30%, above 5.40%, above 5.50%, above 5.60%, above 5.70%, above 5.80%, above 5.90%. Also, from the same point of view, the CaO content is preferably 40.00% or less, and the more preferable order is 35.00% or less, 30.00% or less, 28.00% or less, 26.00% or less, 24.00% or less, 22.00% or less, 21.50% or less. , 21.00% or less, 20.50% or less, 20.25% or less, 20.00% or less, 19.50% or less.

In the glass material for molding of this embodiment, when the glass composition is C, the total content (MgO+CaO+SrO+BaO+ZnO) of MgO, CaO, SrO, BaO, and ZnO belonging to alkaline earth metal oxides is relatively The best is 5.00% or more, and the better order is 7.00% or more, 10.00% or more, 11.00% or more, 12.00% or more, 13.00% or more, 13.50% or more, 14.00% or more, 14.50% or more, 15.00% or more, 15.30% Above, 15.50% or above, 16.00% or above. In addition, the total content (MgO+CaO+SrO+BaO+ZnO) is preferably 50.00% or less, and the more preferable order is 45.00% or less, 40.00% or less, 39.00% or less, 38.00% or less, 37.00% or less, 36.50% Below, 36.00% or less, 35.50% or less, 35.00% or less, 34.50% or less, 34.00% or less. If the total content (MgO+CaO+SrO+BaO+ZnO) is within the above-mentioned range, it is preferable from the viewpoints of lower specific gravity, without hindering high dispersion, and maintaining thermal stability.

In the glass material for molding of this embodiment, when the glass composition is C, among MgO, CaO, SrO, BaO and ZnO, the effective components of MgO and CaO are superior to SrO, BaO and ZnO in terms of suppressing the specific gravity of the glass. . Therefore, from the viewpoint of further suppressing the increase in specific gravity, the mass ratio of the total content of ZnO, SrO, and BaO to the total content of MgO and CaO ((ZnO+SrO+BaO)/(MgO+CaO)) is preferably 2.78 or less, The more preferable order is 2.77 or less, 2.76 or less, 2.75 or less, 2.74 or less, and 2.73 or less. On the other hand, the effect of SrO, BaO, and ZnO on improving partial dispersion characteristics is greater than that of MgO and CaO. Therefore, from the viewpoint of improving partial dispersion characteristics, the mass ratio ((ZnO+SrO+BaO)/(MgO+CaO)) is preferably 0.17 or more, and more preferably 0.18 or more, 0.19 or more, and 0.20 or more in order.

In the molding glass material of this embodiment, when the glass composition is C, the mass ratio of the CaO content to the total content of MgO, CaO, SrO, BaO, and ZnO (CaO/(MgO+CaO+SrO+BaO+ZnO)) From the viewpoint of higher refractive index and lower specific gravity, it is preferably 0.35 or higher, and more preferably 0.36 or higher, 0.37 or higher, 0.38 or higher, 0.39 or higher, 0.40 or higher, 0.41 or higher, 0.42 or higher in order. From the viewpoint of improving thermal stability, the mass ratio (CaO/(MgO+CaO+SrO+BaO+ZnO)) is preferably 1.00 or less, and the more preferable order is 0.95 or less, 0.90 or less, 0.89 or less, 0.88 or less, 0.87 or less, 0.86 or less, 0.85 or less, 0.84 or less, 0.83 or less, 0.80 or less, 0.78 or less.

In the glass material for molding of this embodiment, when the glass composition is C, the total content of CaO and MgO is the mass ratio ((CaO+MgO)/(MgO+CaO) to the total content of MgO, CaO, SrO, BaO, and ZnO +SrO+BaO+ZnO)), from the viewpoint of lower specific gravity, preferably 0.35 or more, and more preferably 0.36 or more, 0.37 or more, 0.38 or more, 0.39 or more, 0.40 or more, 0.41 or more, 0.42 or more in order . From the viewpoint of improving thermal stability, the mass ratio ((CaO+MgO)/(MgO+CaO+SrO+BaO+ZnO) is preferably 1.00 or less, and the more preferable order is 0.95 or less, 0.90 or less, 0.89 or less, 0.88 or less, 0.87 or less, 0.86 or less, 0.85 or less, 0.84 or less, 0.83 or less, 0.80 or less, 0.78 or less.

In the molding glass material of this embodiment, when the glass composition is C, MgO, CaO, SrO, BaO, and ZnO, which are alkaline earth metal oxides, have the effect of lowering the liquidus temperature and improving thermal stability. On the other hand, if these contents are too high, the chemical durability and/or weather resistance tends to be reduced. In addition, although SiO ₂ and B ₂ O ₃ have the effects of improving thermal stability and improving reheating devitrification, if these contents are too large, the meltability tends to be lowered. From the above point of view, _{the mass ratio of the total content of SiO 2} and B ₂ O _{3 to the} total content of MgO, CaO, SrO, BaO, and ZnO ((SiO ₂ +B ₂ O ₃ )/(MgO+CaO+SrO+ BaO+ZnO)), preferably 0.40 or more, and more preferably in the order of 0.45 or more, 0.50 or more, 0.52 or more, 0.54 or more, 0.56 or more, 0.57 or more, 0.58 or more, 0.59 or more, 0.60 or more, 0.61 or more, 0.70 or more , 0.80 or more, 0.90 or more, 1.00 or more, 1.10 or more, more preferably 2.00 or less, and more preferably, the order is 1.80 or less, 1.60 or less, 1.55 or less, 1.50 or less, 1.45 or less, 1.40 or less, and 1.35 or less.

In the glass material for molding of the present embodiment, when the glass composition is C, the MgO content is preferably 0.00% or more. In addition, the MgO content is preferably 15.00% or less, and the more preferable order is 12.00% or less, 9.00% or less, 7.00% or less, 6.00% or less, 5.00% or less, 4.00% or less, 3.50% or less, 3.00% or less, 2.50 % Or less, 2.10% or less.

In the glass material for molding of this embodiment, when the glass composition is C, the SrO content is preferably 0.00% or more, and the more preferable order is 0.10% or more, 0.20% or more, 0.25% or more, 0.26% or more, 0.27% Above, above 0.28%, above 0.29%, above 0.30%, above 0.31%. In addition, the SrO content is preferably 15.00% or less, and the more preferable order is 12.00% or less, 10.00% or less, 9.00% or less, 8.50% or less, 8.00% or less, 7.50% or less, 7.00% or less, 6.50% or less, 6.00 %the following.

In the glass material for molding of this embodiment, in the case of glass composition C, the BaO content is preferably 0.00% or more, and the more preferable order is 0.10% or more, 0.20% or more, 0.30% or more, 0.40% or more, 0.50% Above, 0.60% or above, 0.70% or above, 0.80% or above, 0.90% or above, 1.00% or above, 1.10% or above, 1.20% or above, 1.30% or above. In addition, the BaO content is preferably 25.00% or less, and the more preferable order is 22.00% or less, 20.00% or less, 19.00% or less, 18.00% or less, 17.00% or less, 16.50% or less, 16.00% or less, 15.50% or less, 15.25 % Or less, 15.00% or less.

MgO, CaO, SrO and BaO are all glass components that can improve the thermal stability and devitrification resistance of glass. From the viewpoint of high dispersibility and lower specific gravity, and the viewpoint of improving the thermal stability and devitrification resistance of the glass, the contents of each of the glass components are preferably within the above-mentioned ranges.

In the glass material for molding of the present embodiment, when the glass composition is C, the ZnO content is preferably 0.00% or more. In addition, the ZnO content is preferably 10.00% or less, and more preferably the order is 9.00% or less, 8.00% or less, 7.00% or less, 6.00% or less, 5.00% or less, 4.00% or less, 3.00% or less, and 2.00% or less. ZnO is a glass component that can improve the thermal stability of glass. From the viewpoint of lowering the specific gravity, improving the thermal stability of the glass, and obtaining better optical constants, the content of ZnO is preferably within the above-mentioned range.

In the glass material for molding of this embodiment, when the glass composition is C, the total content _{of La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 belonging to rare earth oxides (La 2} O ₃ +Gd ₂ O ₃ + Y ₂ O ₃ ), from the viewpoint of high refractive index and low dispersion, it is preferably more than 0%, and the more preferable order is 0.50% or more, 1.00% or more, 1.33% or more, 1.50% or more, 2.00% Above, 2.50% or more, 3.00% or more. From the viewpoint of lower specific gravity, the total content of _{La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 (La 2} O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) is preferably 30.00% or less, more preferably The order is 29.00% or less, 28.00% or less, 26.00% or less, 24.00% or less, 22.00% or less, 20.00% or less, 18.00% or less, 16.00% or less, 15.00% or less, 14.50% or less, 14.00% or less, 13.50% Or less, 13.00% or less, 12.50% or less, 12.00% or less.

In the glass material for molding of this embodiment, when the glass composition is C, BaO, and La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ which are rare earth oxides are all contributing to low dispersibility ( That is, the components of the Abbe number (νd) are increased, but if the content of these components is too high, the specific gravity of the glass tends to increase. From the above point of view, in the case of glass composition C, the total content of _{BaO, and rare earth oxides La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 (BaO+La 2} O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ), preferably below 30.00%, and in a more preferred order, below 29.00%, below 28.00%, below 27.00%, below 26.00%, below 25.00%, below 24.50%, below 24.00%, below 23.50%, 23.00% or less. Also, from the viewpoint of increasing the Abbe number νd, the _{total content of BaO, La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ (BaO+La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) is preferable More than 0%, and the best order is 1.00% or more, 2.00% or more, 3.00% or more, 4.00% or more, 5.00% or more, 6.00% or more, 7.00% or more, 7.50% or more, 8.00% or more, 8.50% or more .

In the glass material for molding of the present embodiment, in the case of glass composition C, both BaO and La ₂ O ₃ are low-dispersion components, but BaO is smaller than La ₂ O ₃ in terms of the effect of increasing the refractive index. Therefore, from the viewpoint of increasing the refractive index, the mass ratio of the _{BaO content to the La 2} O _{3 content (BaO/La 2} O ₃ ) is preferably 8.30 or less, and the more preferable order is 8.00 or less, 7.50 or less, and 7.00 or less. , 6.50 or less, 6.00 or less, 5.50 or less, 5.40 or less, 5.30 or less, 5.20 or less, 5.10 or less, 5.00 or less, 4.90 or less, 4.80 or less, 4.70 or less. In the glass material for molding of the present embodiment, in the case of glass composition C, the mass ratio (BaO/La ₂ O ₃ ) may be 0 or may be 0.00 or more. From the viewpoint of maintaining the thermal stability of the glass, the mass ratio (BaO/La ₂ O ₃ ) is preferably more than 0.00, and the more preferable order is 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.10 or more, 0.11 or more.

In the glass material for molding of this embodiment, when the glass composition is C, La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ , which are rare earth oxides, contribute to the improvement of refractive index and low dispersion. If the content is too large, the thermal stability tends to decrease. In addition, although SiO ₂ and B ₂ O ₃ have an effect of improving thermal stability, if these contents are too high, the solubility tends to decrease and the refractive index tends to decrease. From the above point of view, the mass ratio of the total content of _{SiO 2} and B ₂ O _{3 to the} total content of La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 ((SiO 2} +B ₂ O ₃ )/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )), preferably more than 0.00, and more preferably, the order is 0.25 or more, 0.50 or more, 0.75 or more, 1.00 or more, 1.25 or more, 1.50 or more, 1.75 or more, 1.80 or more , 1.85 or more, and preferably 7.47 or less, and more preferably, the order is 7.40 or less, 7.35 or less, 7.30 or less, and 7.25 or less.

In the glass material for molding of this embodiment, when the glass composition is C, La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ are all components that can increase the refractive index of the glass, but in terms of increasing the specific gravity, Gd ₂ O ₃ and Y ₂ O ₃ are components of La ₂ O _{3 that} can further increase the specific gravity ratio. So, from the much lower proportion of view, La ₂ O ₃ content with respect to La ₂ O _3, the quality of Gd ₂ O ₃ and Y ₂ O ₃ total content ratio of _{(La 2 O 3 / (La} 2 O 3 + Gd ₂ O ₃ +Y ₂ O ₃ )), preferably more than 0.00, and more preferably in the order of 0.10 or more, 0.20 or more, 0.30 or more, 0.40 or more, 0.50 or more, 0.60 or more, 0.70 or more, and 0.75 or more. The mass ratio (La ₂ O ₃ /(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )) can be set to 1.00 or less. It From the same viewpoint, when the glass composition C, Gd ₂ O ₃ content with respect to La ₂ O _3, the quality of Gd ₂ O ₃ and Y ₂ O ₃ the total content ratio _{(Gd 2 O 3 / (La} 2 O 3 +Gd ₂ O ₃ +Y ₂ O ₃ )), preferably less than 1.00, and more preferably in the order of 0.90 or less, 0.80 or less, 0.70 or less, 0.60 or less, 0.50 or less, 0.40 or less, 0.30 or less, 0.25 or less, Below 0.20. The mass ratio (Gd ₂ O ₃ /(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )) can be set to 0.00 or more. Moreover, it is from the same viewpoint, when the glass composition C, Y ₂ O ₃ with respect to the content of La ₂ O _3, Gd ₂ O ₃ by mass and the total content of Y ₂ O ₃ ratio of (Y ₂ O ₃ / (La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )), preferably less than 1.00, and more preferably in the order of 0.90 or less, 0.80 or less, 0.70 or less, 0.60 or less, 0.50 or less, 0.40 or less, 0.30 or less, 0.25 or less. The mass ratio (Y ₂ O ₃ /(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )) can be set to 0.00 or more.

In the glass material for molding of the present embodiment, in the case of glass composition C, from the above viewpoint, the contents of the above-mentioned components belonging to the rare-earth group oxide are preferably all within the following ranges. The _{content of La 2} O _{3 is} preferably 0.00% or more, and more preferably, the order is more than 0.00%, 0.50% or more, 1.00% or more, 1.33% or more, 1.50% or more, 2.00% or more, 2.50% or more, 2.75% or more, 3.00% or more. In addition, the La ₂ O ₃ content is preferably 30.00% or less, and the more preferable order is 25.00% or less, 20.00% or less, 18.00% or less, 16.00% or less, 15.00% or less, 14.00% or less, 13.50% or less, 13.00% Below, 12.50% or less, 12.00% or less. The _{content of Gd 2} O _{3 is} preferably 0.00% or more. In addition, the _{content of Gd 2} O _{3 is} preferably 10.00% or less, and the more preferable order is 9.00% or less, 8.00% or less, 7.00% or less, 6.00% or less, 5.00% or less, 4.00% or less, 3.00% or less, 2.00% the following. The _{content of Y 2} O _{3 is} preferably 0.00% or more. In addition, the Y ₂ O ₃ content is preferably 10.00% or less, and the more preferable order is 9.00% or less, 8.00% or less, 7.00% or less, 6.00% or less, 5.00% or less, 4.00% or less, 3.00% or less, 2.00% the following.

In the glass material for molding of the present embodiment, when the glass composition is C, the La ₂ O ₃ system has an effect of increasing the refractive index of the glass, and the B ₂ O ₃ system has a tendency to lower the refractive index of the glass. Therefore, from the viewpoint of higher refractive index, the mass ratio of the _{La 2} O ₃ content to the B ₂ O _{3 content (La 2} O ₃ /B ₂ O ₃ ) is preferably 1.30 or more, and the order is more preferable. 1.35 or higher, 1.40 or higher, 1.45 or higher, 1.50 or higher, 1.55 or higher, 1.60 or higher, 1.65 or higher, 1.70 or higher, 1.72 or higher. From the viewpoint of lower specific gravity, the mass ratio (La ₂ O ₃ /B ₂ O ₃ ) is preferably 20.00 or less, and the more preferable order is 18.00 or less, 16.00 or less, 14.00 or less, 13.00 or less, 12.00 or less, 11.50 Below, 11.00 or less, 10.50 or less, 10.00 or less.

In the glass material for molding of this embodiment, in the case of glass composition C, the mass ratio of the _{B 2} O ₃ content to the La ₂ O _{3 content (B 2} O ₃ /La ₂ O ₃ ) is preferably 0.79 or less, and more The best order is 0.78 or less, 0.77 or less, 0.76 or less, 0.75 or less, 0.70 or less, 0.65 or less, 0.64 or less, 0.62 or less, 0.61 or less, 0.60 or less, 0.59 or less, 0.58 or less, 0.57 or less, 0.50 or less. The mass ratio (La ₂ O ₃ /B ₂ O ₃ ) is preferably 0.00 or more, and more preferably exceeds 0.00.

In the glass material for molding of this embodiment, when the glass is composed of C, rare earth oxides can increase the refractive index of the glass. However, if the content of rare earth oxides is too high, the thermal stability will decrease and the glass will melt. Tendency to decrease sex. Therefore, from the viewpoint of maintaining the thermal stability of glass and increasing the refractive index, the _{total content of La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 is} relative to BaO, La ₂ O ₃ , Gd ₂ O ₃ and Y The mass ratio of the total content of ₂ O _{3 ((La 2} O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )/(BaO+La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )), preferably 1.00 Below, the more preferable order is less than 1.00, 0.99 or less, 0.98 or less, 0.97 or less, 0.96 or less, 0.95 or less, 0.94 or less, 0.93 or less, 0.92 or less, 0.91 or less, and 0.90 or less. The mass ratio ((La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )/(BaO+La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )) is preferably more than 0.00, and the order is better It is 0.05 or higher, 0.06 or higher, 0.07 or higher, 0.08 or higher, 0.09 or higher, 0.10 or higher, 0.11 or higher, 0.12 or higher, 0.13 or higher, 0.14 or higher, 0.15 or higher, 0.16 or higher, 0.17 or higher, 0.18 or higher, 0.20 or higher.

In the glass material for molding of the present embodiment, when the glass composition is C, the rare earth oxide can increase the refractive index of the glass, but if the content is too large, the glass meltability tends to decrease. On the other hand, although alkaline earth metal oxides can improve the meltability of the glass, if the content is too large, the refractive index tends to be lowered. Therefore, from the viewpoint of increasing the refractive index while maintaining the glass meltability, the _{total content of La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 is} relative to MgO, CaO, SrO, BaO, ZnO, La ₂ The mass ratio of the total content of O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 ((La 2} O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )/(MgO+CaO+SrO+BaO+ZnO+La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )), preferably more than 0.00, more preferably, the order is more than 0.01, more than 0.02, more than 0.03, more than 0.04, more than 0.05, more than 0.06, more than 0.07, more than 0.08, and , Preferably 0.85 or less, more preferably, the order is 0.80 or less, 0.75 or less, 0.70 or less, 0.65 or less, 0.60 or less, 0.55 or less, 0.50 or less, 0.45 or less, 0.44 or less, 0.43 or less, 0.42 or less, 0.41 or less, 0.40 the following.

In the glass material for molding of the present embodiment, when the glass composition is C, the rare earth oxide can increase the refractive index of the glass, but if the content is too large, the thermal stability of the glass tends to decrease. On the other hand, although B ₂ O ₃ can improve the thermal stability of the glass, if the content is too large, the refractive index tends to be lowered. Therefore, from the viewpoint of further increasing the refractive index while maintaining the thermal stability of the glass, the mass ratio of the _{B 2} O ₃ content to the _{total content of BaO, La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 (} B ₂ O ₃ /(BaO+La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )), preferably more than 0.00, more preferably, the order is more than 0.00, more than 0.01, more than 0.02, more than 0.03, and , Preferably 1.00 or less, and more preferably the order is 0.90 or less, 0.80 or less, 0.70 or less, 0.60 or less, 0.55 or less, 0.50 or less, 0.45 or less, 0.40 or less, 0.35 or less in this order.

In the glass material for molding of this embodiment, in the case of glass composition C, although La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ have the effect of increasing the refractive index of the glass, if the total content of these is too large , There will be a tendency for thermal stability to decrease. On the other hand, although B ₂ O ₃ has the effect of improving the thermal stability of the glass, it has a tendency to lower the refractive index. Therefore, from the viewpoint of increasing the refractive index while maintaining the thermal stability of the glass, the _{total content of La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 is} relative to that of B ₂ O ₃ , La ₂ O ₃ , and Gd ₂ O ₃ And the mass ratio of the total content of _{Y 2} O _{3 ((La 2} O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )/(B ₂ O ₃ +La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )) , Preferably 0.57 or more, more preferably 0.58 or more, 0.59 or more, 0.60 or more, 0.61 or more, 0.62 or more, 0.63 or more, and 0.64 or more in order. From the viewpoint of lower specific gravity, the mass ratio ((La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )/(B ₂ O ₃ +La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) ) Is preferably 1.00 or less, and more preferably, the order is less than 1.00, 0.99 or less, 0.98 or less, 0.97 or less, 0.96 or less, 0.95 or less, 0.94 or less, 0.93 or less, 0.92 or less, 0.91 or less, 0.90 or less, 0.89 or less, 0.88 or less, 0.87 or less, 0.86 or less, 0.85 or less.

In the glass material for molding of this embodiment, when the glass composition is C, although La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and ZrO ₂ have the effect of increasing the refractive index and improving the partial dispersion characteristics, if If the _{content of ZrO 2 is} too large, the glass meltability tends to decrease. It From the above viewpoint, ZrO ₂ content of the La ₂ O _3, the quality of _{Gd 2 O 3, Y 2 O} 3 and ZrO ₂ total content ratio _{(ZrO 2 / (La 2 O} 3 + Gd 2 O 3 + Y 2 O ₃ +ZrO ₂ )), preferably 0.01 or more, more preferably 0.02 or more, 0.03 or more, 0.04 or more in sequence, more preferably 5.00 or less, more preferably 4.00 or less, 3.00 or less, 2.00 in sequence the following.

In the glass material for molding of this embodiment, when the glass composition is C, La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and ZrO ₂ are all components that increase the refractive index, but ZrO _{2 is} compared to La ₂ Under O ₃ , Gd ₂ O ₃ , and Y ₂ O ₃ , the effect of increasing the refractive index is greater, and the effect of improving dispersion (the effect of reducing Abbe value) is also greater. It is from the viewpoint of maintaining low dispersion, ZrO ₂ content of the La ₂ O _3, the quality of Gd ₂ O ₃ and Y ₂ O ₃ the total content ratio _{(ZrO 2 / (La 2 O} 3 + Gd 2 O 3 + Y 2 O ₃ )), preferably 3.30 or less, and more preferably in the order of 3.00 or less, 2.90 or less, 2.80 or less, 2.70 or less, 2.60 or less, 2.50 or less, 2.40 or less, 2.30 or less, 2.20 or less, 2.10 or less, 2.00 or less, 1.90 Below, 1.80 or less, 1.70 or less, 1.60 or less, 1.50 or less, 1.40 or less, 1.30 or less, 1.25 or less. The mass ratio (ZrO ₂ /(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )) can be set to 0.00 or more. From the viewpoint of increasing the refractive index, it is preferably more than 0.00, and the order is better. It is 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, and 0.06 or more.

In the glass material for molding of this embodiment, when the glass is composed of C, the ZrO ₂ content is preferably 7.63% or less from the viewpoint of achieving better optical constants and improving partial dispersion characteristics, and more preferably, the order is in order. Full 7.63%, the better order is 7.60 or less, 7.50 or less, 7.40 or less, 7.30 or less, 7.20 or less, 7.10 or less, 7.00 or less, 6.90 or less, 6.80 or less, 6.70 or less, 6.60 or less, 6.50 or less, 6.40 or less, 6.30 Below, 6.20 or less, 6.10 or less, 6.00 or less, 5.95 or less, 5.90 or less, especially from the viewpoint of improving reheating devitrification, preferably 6.00 or less, and more preferably 5.50 or less, 5.00 or less, 4.00 or less, 3.00 or less, 2.50 or less. In addition, _{from the viewpoint of achieving better optical constants and improving partial dispersion characteristics, the content of ZrO 2} is preferably 0.00% or more, and more preferably in the order of more than 0.00%, 0.10% or more, 0.20% or more, and 0.30% or more , 0.40% or more, 0.50% or more, 0.60% or more, 0.65% or more, 1.10% or more, and 1.60% or more.

In the glass material for molding of this embodiment, when the glass is composed of C, although MgO, CaO, SrO, BaO, and ZnO have the effect of improving the thermal stability of the glass, if the content of these is too high, it will decrease The tendency of the refractive index. On the other hand, although La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ have the effect of increasing the refractive index, if these contents are too large, the thermal stability tends to be lowered. From the above point of view, the total content of MgO, CaO, SrO, BaO, and ZnO is _{the mass ratio of the total content of La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ ((MgO+CaO+SrO+BaO+ZnO )/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )), preferably more than 0.00, more preferably, the order is 0.10 or more, 0.20 or more, 0.30 or more, 0.40 or more, 0.50 or more, 0.60 or more, 0.70 or more, 0.80 or more, 0.90 or more, 1.00 or more, 1.10 or more, 1.20 or more, 1.30 or more, 1.40 or more, and preferably 20.00 or less, and more preferably, the order is 18.00 or less, 16.00 or less, 14.00 or less, 11.09 or less, 11.08 or less, 11.07 or less, 11.06 or less, 11.05 or less, 11.04 or less, 11.03 or less, 11.02 or less, 11.01 or less, 11.00 or less.

In the glass material for molding of the present embodiment, in the case of glass composition C, SrO, BaO, La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ are all effective components capable of maintaining low dispersibility. Therefore, from the viewpoint of maintaining lower dispersibility, the _{total content of SrO, BaO, La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ (SrO+BaO+La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ), preferably 9.00% or more, more preferably 9.50% or more, 10.00% or more, 10.50% or more, 11.00% or more, 11.50% or more, 12.00% or more, 12.50% or more, 13.00% or more, 13.50% in order above,. Furthermore, in the glass material for molding of the present embodiment, when the glass composition is C, the total content (SrO+BaO+La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ ) Preferably, it is 45.00% or less, and the more preferable order is 40.00% or less, 35.00% or less, 30.00% or less, 29.00% or less, 28.00% or less, 27.00% or less, 26.00% or less, and 25.00% or less.

In the glass material for molding of this embodiment, when the glass is composed of C, La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ are components that increase the refractive index, and SiO ₂ is a component that maintains the thermal stability of the glass. Ingredients. The mass ratio of the total content of La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 to the} total content of La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ and SiO _{2 ((La 2} O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ +SiO ₂ )), from the viewpoint of further increasing the refractive index, it is preferably 0.12 or more, more preferably 0.13 or more . From the viewpoint of maintaining the thermal stability of the glass, the mass ratio ((La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )/(La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ +SiO ₂ )) It is preferably 0.70 or less, and more preferably, the order is 0.60 or less, 0.50 or less, 0.49 or less, 0.48 or less, 0.47 or less, 0.46 or less, 0.45 or less, 0.44 or less, 0.43 or less, 0.42 or less, and 041 or less in this order.

In the glass material for molding of this embodiment, in the case of glass composition C, the _{total content of SiO 2} and CaO is relative to the total content of TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O ₃ The mass ratio ((SiO ₂ +CaO)/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), the denominator system belongs to the total content of the major components that increase the refractive index, and the molecular system Effective for the total content of low dispersion and low specific gravity components. From the viewpoint of maintaining high refractive index and low dispersion, and maintaining low specific gravity and thermal stability, the mass ratio ((SiO ₂ +CaO)/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )) is preferably 1.20 or less, and the more preferable order is 1.09 or less, 1.08 or less, 1.07 or less, 1.06 or less, 1.05 or less, 1.04 or less, 1.03 or less, 1.02 or less, 1.01 or less, 0.99 or less, 0.94 in order Below, 0.89 or less, 0.86 or less. In addition, from the viewpoint of maintaining higher refractive index, lower dispersibility, and lower specific gravity, the mass ratio ((SiO ₂ +CaO)/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )) is preferably 0.25 or more, more preferably 0.30 or more, 0.35 or more, 0.40 or more, 0.42 or more, 0.44 or more, 0.46 or more, 0.48 or more, 0.50 or more, 0.52 or more, 0.54 or more, 0.55 in order in order above.

In the glass material for molding of this embodiment, in the case of glass composition C, among ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ , and Bi ₂ O ₃ , which are _{components of increasing refractive index, ZrO 2} The effect of improving dispersion is small. So, from the viewpoint of maintaining the lower dispersibility, ZrO ₂ content of the _{TiO 2, Nb 2 O 5,} Ta 2 O 5, WO _3, and the quality of Bi ₂ O ₃ ratio of the total content of (ZrO ₂ / (TiO ₂ + Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), preferably 0.00 or more, more preferably 0.01 or more and 0.02 or more in order. From the viewpoint of maintaining the thermal stability of the glass, and maintaining the devitrification resistance when the glass is heated to soften it and then press forming (stability during reheating press forming: also known as "reheat press formability"), the mass ratio (ZrO ₂ /(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )) is preferably 0.21 or less, more preferably, the order is 0.20 or less, 0.19 or less, 0.18 or less, 0.17 or less, 0.16 Below, 0.15 or less, 0.12 or less, 0.10 or less, 0.08 or less, 0.06 or less.

In the glass material for molding of this embodiment, when the glass is composed of C, the lower limit of the total content of _{Li 2} O, Na ₂ O, and K _{2 O [Li 2} O+Na ₂ O+K _{2 O] is preferably 0.1} %, the better order is 0.2%, 0.5%, 1.0%, 1.2%, 1.5%. In addition, the upper limit of the total content is preferably 20%, and a more preferable order is 15%, 10%, 8%, 6%, 4%, 2%.

In the glass composition C, when _{the lower limit of the total content [Li 2} O+Na ₂ O+K ₂ O] satisfies the above, the meltability of the glass can be improved, and the rise in the liquidus temperature can be suppressed. Moreover, when the upper limit of the total content satisfies the above, the viscosity of the glass can be increased, the crystallization rate of the glass melt can be reduced, and the stability during reheating can be improved.

In the glass material for molding of this embodiment, when the glass is composed of C, Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O, which are alkali metal oxides, have the effect of improving partial dispersion characteristics, and also have Reduce the liquidus temperature and improve the thermal stability of the glass. From these viewpoints, the total content of _{Li 2} O, Na ₂ O, K ₂ O, and Cs _{2 O (Li 2} O+Na ₂ O+K ₂ O+Cs ₂ O) is preferably at least 0.00%, and the order is more preferable The order is more than 0.00%, more than 0.05%, more than 0.10%, more than 0.15%, more than 0.20%, more than 0.25%, more than 0.28%, more than 0.60%, more than 1.10%, more than 1.30%, more than 1.60%. From the viewpoint of improving chemical durability and weather resistance, the total content (Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O) is preferably 20.00% or less, and the more preferable order is 18.00% or less and 16.00% in order. Below, 14.00% or less, 12.00% or less, 10.00% or less, 9.00% or less, 8.00% or less, 7.00% or less, 6.50% or less, 6.00% or less, 5.50% or less, 5.00% or less, 4.50% or less, 3.90% or less, 2.90% or less, 2.40% or less.

In the glass material for molding of this embodiment, when the glass composition is C, the _{total content of Li 2} O, Na ₂ O, K ₂ O, and Cs ₂ O is relative to the total of SiO ₂ , P ₂ O ₅ and B ₂ O ₃ The upper limit of the content mass ratio [(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)/(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )], preferably 1.0, more preferably in order It is 0.7, 0.5, 0.4, 0.3, 0.2, 0.1, 0.09, 0.08. In addition, the lower limit of the mass ratio is preferably 0.001, and the more preferable order is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06.

In the glass composition C, if the mass ratio [(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)/(SiO ₂ +P ₂ O ₅ +B ₂ O ₃ )] is too low, there will be melting Worries of deterioration. In addition, if it is too high, in addition to lowering the viscosity during melting of the glass and lowering the thermal stability of the melt, there is also a possibility of deterioration in stability during reheating.

In the glass material for molding of this embodiment, when the glass composition is C, the _{total content of Li 2} O, Na ₂ O, K ₂ O, and Cs ₂ O is relative to Nb ₂ O ₅ , TiO ₂ , WO ₃ and Bi ₂ The upper limit of the mass ratio of the total content of _{O 3 [(Li 2} O+Na ₂ O+K ₂ O+Cs ₂ O)/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] is preferably 1.0 , The better order is 0.5, 0.3, 0.2, 0.1, 0.09, 0.08, 0.07, 0.06, 0.05. In addition, the lower limit of the mass ratio is preferably 0.005, and the more preferable order is 0.01, 0.02, 0.03, 0.04 in this order.

In the glass composition C, if the mass ratio [(Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O)/(Nb ₂ O ₅ +TiO ₂ +WO ₃ +Bi ₂ O ₃ )] is too low, There is a concern that the dispersion ratio of Pg and F may increase and the penetration rate may deteriorate. In addition, if it is too high, in addition to an increase in the Abbe number and a decrease in the refractive index, there is also a risk of deterioration in stability during reheating.

In the glass material for molding of the present embodiment, when the glass composition is C, although alkali metal oxides and alkaline earth metal oxides contribute to maintaining glass meltability and thermal stability, if these contents are too high, There will be a tendency for the meltability and thermal stability of the glass to decrease. Therefore, from the viewpoint of maintaining the meltability and thermal stability of the glass, Li ₂ O, Na ₂ O, K ₂ O, and Cs ₂ O, which are alkali metal oxides, and MgO, CaO, and CaO, which are alkaline earth metal oxides The total content of SrO and BaO (Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O+MgO+CaO+SrO+BaO), preferably more than 5.00%, and more preferably in the order of more than 7.00%, 9.00 % Or more, 10.00% or more, 12.00% or more, 14.00% or more, 15.00% or more, 16.00% or more, 17.00% or more, 18.00% or more, 18.50% or more, more preferably 50.00% or less, more preferably in order 48.00% or less, 46.00% or less, 44.00% or less, 43.00% or less, 42.00% or less, 41.00% or less, 40.00% or less, 39.00% or less, 38.00% or less, 37.00% or less, 36.00% or less, 35.00% or less, 34.50% Below, below 34.00%.

In the glass material for molding of the present embodiment, when the glass composition is C, although the alkali metal oxides and alkaline earth metal oxides have the effect of lowering the liquidus temperature and improving the thermal stability, if these contents are relative to If the glass has too many network-forming components, the chemical durability and weather resistance tend to decrease. In addition, although SiO ₂ and B ₂ O ₃ have an effect of improving thermal stability, if these contents are too large, the meltability tends to decrease. From these viewpoints, the mass ratio of the total content of _{Li 2} O, Na ₂ O, K ₂ O, Cs ₂ O, MgO, CaO, SrO, and BaO to the total content of SiO ₂ and B ₂ O _{3 ((} Li ₂ O+Na ₂ O+K ₂ O+Cs ₂ O+MgO+CaO+SrO+BaO)/(SiO ₂ +B ₂ O ₃ )), preferably 0.50 or more, more preferably 0.52 or more in sequence , 0.54 or more, 0.56 or more, 0.58 or more, 0.60 or more, 0.62 or more, 0.64 or more, 0.66 or more, 0.68 or more, 0.70 or more, 0.72 or more, 0.74 or more, 0.75 or more, 0.76 or more, 0.77 or more, 0.78 or more, 0.79 or more, and , Preferably 5.00 or less, and more preferably the order is 4.50 or less, 4.00 or less, 3.50 or less, 3.00 or less, 2.50 or less, 2.00 or less, 1.90 or less, 1.80 or less, 1.70 or less, 1.65 or less, and 1.60 or less.

In the glass material for molding of the present embodiment, when the glass composition is C, among Li ₂ O, Na ₂ O, and K ₂ O, Li ₂ O is the component that is the least likely to lower the refractive index. So, from the viewpoint of even higher refractive index, Li ₂ O content of the Li ₂ O, Na ₂ O and quality of K ₂ O ratio of the total content of _{(Li 2 O / (Li 2} O + Na 2 O + K 2 O)), preferably 0.00 or more, more preferably in the order of more than 0.00, 0.10 or more, 0.20 or more, 0.30 or more, 0.40 or more, 0.45 or more. On the other hand, the mass ratio (Li ₂ O/(Li ₂ O+Na ₂ O+K ₂ O)) system can be set to, for example, 1.00 or less. In addition, from the viewpoint of suppressing the decrease in reheating devitrification, it can also be set It is 0.99 or less, 0.98 or less, 0.95 or less, 0.90 or less, 0.80 or less, 0.70 or less, 0.65 or less, 0.60 or less, and 0.50 or less.

In the glass material for molding of this embodiment, when the glass is composed of C, although Li ₂ O, Na ₂ O, K ₂ O, MgO, CaO, SrO, BaO, and ZnO can improve the thermal stability of the glass and improve the glass Because of the effect of meltability, if _{the total content of Li 2} O, Na ₂ O, and K ₂ O is too high, the glass tends to exhibit high dispersibility. Therefore, from the viewpoint of obtaining better dispersibility, the _{total content of Li 2} O, Na ₂ O, and K ₂ O is the mass ratio ((Li ₂ O+Na ₂ O+K ₂ O)/(MgO+CaO+SrO+BaO+ZnO)), preferably 0.00 or more, and more preferably in the order of more than 0.00, 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, In addition, it is preferably 4.00 or less, and more preferably, the order is 3.50 or less, 3.00 or less, 2.50 or less, 2.00 or less, 1.50 or less, 1.00 or less, 0.90 or less, 0.80 or less, 0.70 or less, 0.60 or less, 0.50 or less, 0.40 or less, Below 0.35.

In the glass material for molding of this embodiment, in the case of glass composition C, the _{total content of Li 2} O, Na ₂ O, and K ₂ O is the mass ratio relative to the total content of SiO ₂ and B ₂ O _{3 ((Li 2} O +Na ₂ O+K ₂ O)/(SiO ₂ +B ₂ O ₃ )), from the viewpoint of maintaining thermal stability and/or maintaining reheat stamping formability, it is preferably 1.00 or less, more preferably in order It is 0.90 or less, 0.80 or less, 0.70 or less, 0.60 or less, 0.50 or less, 0.40 or less, 0.35 or less, 0.30 or less, 0.25 or less. From the viewpoint of maintaining meltability and/or reducing the partial dispersion ratio to provide glass suitable for high-order chromatic aberration correction, the mass ratio ((Li ₂ O+Na ₂ O+K ₂ O)/(SiO ₂ +B ₂ O) ₃ )) It is preferably 0.00 or more, and more preferably, the order is more than 0.00, 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, and 0.05 or more in order.

In the glass material for molding of this embodiment, in the case of glass composition C, the _{content of Li 2} O is preferably 0.00% or more, and the more preferable order is 0.05% or more, 0.10% or more, 0.15% or more, 0.20% or more, 0.25% or more, 0.30% or more, 0.40% or more, 0.50% or more, 0.60% or more. In addition, the Li ₂ O content is preferably 14.00% or less, and the more preferable order is 12.00% or less, 10.00% or less, 8.00% or less, 7.00% or less, 6.50% or less, 6.00% or less, 5.50% or less, and 5.00% or less. . From the viewpoint of achieving better optical constants, and from the viewpoint of maintaining chemical durability, weather resistance, and stability during reheating, it is preferable to set the Li ₂ O content within the above-mentioned range.

In the glass material for molding of the present embodiment, when the glass composition is C, the Na ₂ O content is preferably 0.00% or more. In addition, the Na ₂ O content is preferably 10.00% or less, and the more preferable order is 8.00% or less, 7.00% or less, 6.00% or less, 5.00% or less, 4.00% or less, 3.00% or less, and 2.00% or less. Setting the Na ₂ O content within the above range is preferable from the viewpoint of improving partial dispersion characteristics.

In the glass material for molding of the present embodiment, when the glass composition is C, the K ₂ O content is preferably 0.00% or more. In addition, the K ₂ O content is preferably 10.00% or less, and the more preferable order is 8.00% or less, 7.00% or less, 6.00% or less, 5.00% or less, 4.00% or less, 3.00% or less, and 2.00% or less. It is preferable to set the K ₂ O content within the above-mentioned range from the viewpoint of improving the thermal stability of the glass.

In the glass material for molding of this embodiment, when the glass is composed of C, the Cs ₂ O content is preferably 5.00% or less, and the more preferable order is 4.00% or less, 3.00% or less, 2.00% or less, 1.00% or less, Below 0.50%, it can also be 0%.

In the glass material for molding of this embodiment, when the glass composition is C, the total content of _{TiO 2} , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O _{3 (TiO 2} +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ ), from the viewpoint of higher refractive index, preferably 30.00% or more, and more preferably 31.00% or more, 32.00% or more, 33.00% or more, 34.00% in this order Above, above 35.00%, above 36.00%, above 36.50%, above 37.00%, above 37.55%. From the viewpoint of lowering specific gravity and improving thermal stability, the total content of _{TiO 2} , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O _{3 (TiO 2} +Nb ₂ O ₅ +Ta ₂ O ₅ + WO ₃ +Bi ₂ O ₃ ), preferably 60.00% or less, and more preferably in the order of 58.00% or less, 56.00% or less, 54.00% or less, 52.00% or less, 51.00% or less, 50.00% or less, 49.50% or less, 49.00% or less, 48.50% or less.

In the glass material for molding of this embodiment, in the case of glass composition C, the _{total content of SiO 2} and B ₂ O _{3 is} relative to the total of TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O ₃ The mass ratio of the content ((SiO ₂ +B ₂ O ₃ )/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )) can be obtained by suppressing the increase in specific gravity. From the viewpoint of refractive index glass, it is preferably 0.75 or less. In addition to the above, the mass ratio ((SiO ₂ +B ₂ O ₃ )/(TiO ₂ + Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )) is preferably 0.16 or more, and the more preferable order is 0.20 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.36 or more, 0.37 or more, 0.38 Above, 0.39 or above, 0.40 or above, 0.41 or above, 0.42 or above, more preferably 0.75 or below, and more preferably in the order of 0.74 or below, 0.73 or below, 0.72 or below, 0.71 or below, 0.70 or below, 0.69 or below, 0.68 or below, 0.67 Below, 0.66 or less, 0.65 or less, 0.64 or less.

In the glass material for molding of the present embodiment, when the glass composition is C, SiO ₂ and B ₂ O ₃ have the effect of lowering the refractive index and lowering the dispersion (increasing the Abbe number). On the other hand, TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , and ZrO ₂ are high refractive index and high dispersion components. From the viewpoint of increasing the refractive index, the total content of _{SiO 2} and B ₂ O _{3 is} the mass ratio of the total content of _{TiO 2} , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ , Bi ₂ O ₃ and ZrO _{2 (} (SiO ₂ +B ₂ O ₃ )/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ +ZrO ₂ )), preferably 0.64 or less, more preferably 0.63 in order Below, 0.62 or less, 0.61 or less, 0.60 or less, 0.59 or less, 0.58 or less. On the other hand, in the case of glass composition C, from the viewpoint of suppressing high dispersion, the mass ratio ((SiO ₂ +B ₂ O ₃ )/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ +ZrO ₂ )) is preferably 0.13 or more, more preferably, the order is 0.15 or more, 0.20 or more, 0.25 or more, 0.26 or more, 0.27 or more, 0.28 or more, 0.29 or more, 0.30 or more, 0.31 or more, 0.32 or more, 0.33 or more, 0.34 or more, 0.35 or more, 0.36 or more, 0.37 or more, 0.38 or more.

In the glass material for molding of this embodiment, when the glass composition is C, the _{total content of Li 2} O, Na ₂ O, and K ₂ O is relative to TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi The mass ratio of the total content of ₂ O _{3 ((Li 2} O+Na ₂ O+K ₂ O)/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )) can be improved from From the viewpoint of partial dispersion characteristics and transmittance, it is preferably 0.00 or more, and more preferably 0.01 or more in order. From the viewpoint of maintaining glass thermal stability and/or reheat stamping formability, the mass ratio ((Li ₂ O+Na ₂ O+K ₂ O)/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )) is preferably 0.67 or less, and more preferably, the order is 0.60 or less, 0.50 or less, 0.40 or less, 0.30 or less, 0.20 or less, 0.15 or less, and 0.10 or less.

In the glass material for molding of this embodiment, when the glass is composed of C, although MgO, CaO, SrO, BaO, and ZnO have the effect of improving the thermal stability of the glass, if the content of these is too high, there will be refraction. There is a tendency to decrease the rate, and there is a tendency for the glass to exhibit lower dispersibility. On the other hand, although TiO ₂ , Nb ₂ O ₅ , WO ₃ and Bi ₂ O ₃ have a tendency to increase the refractive index and make the glass more dispersible, if the content of these is too high, the thermal stability will decrease. Propensity. It From the above point of view, MgO, CaO, SrO, BaO and ZnO total content, with respect to the mass of _{TiO 2, Nb 2 O 5,} Ta 2 O 5, 2 O 3 the total content of WO ₃ and Bi ratio ((MgO + CaO +SrO+BaO+ZnO)/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), preferably 0.09 or more, and more preferably the order is 0.10 or more, 0.15 or more, 0.20 or more, 0.21 or more, 0.22 or more, 0.23 or more, 0.24 or more, 0.25 or more, 0.26 or more, 0.27 or more, 0.28 or more, 0.29 or more, 0.30 or more, 0.31 or more, 0.32 or more, 0.35 or more, 0.40 or more, 0.45 or more, and, It is preferably 1.66 or less, and the more preferable order is 1.60 or less, 1.50 or less, 1.40 or less, 1.30 or less, 1.20 or less, 1.10 or less, 1.00 or less, 0.95 or less, 0.90 or less, 0.88 or less, 0.80 or less, 0.70 or less, 0.60 or less , 0.50 or less.

In the glass material for molding of this embodiment, when the glass composition is C, among MgO, CaO, SrO, BaO, and ZnO, MgO, CaO is lower than SrO, BaO, and ZnO, which suppresses the increase in the specific gravity of the glass. And reduce the effective components of _{α 100-300} and α _max. Therefore, from the viewpoint of suppressing the increase in specific gravity, the total content of ZnO, SrO, and BaO is preferably 1.98 or less as the mass ratio of the total content of MgO and CaO ((ZnO+SrO+BaO)/(MgO+CaO)). The best order is 1.96 or less, 1.94 or less, 1.92 or less, 1.90 or less, 1.88 or less, 1.86 or less, 1.85 or less, 1.84 or less, 1.83 or less, 1.82 or less, 1.81 or less, 1.80 or less, 1.79 or less, 1.78 or less, and 1.50 or less , 1.20 or less, 0.95 or less, 0.80 or less, 0.70 or less, 0.60 or less, 0.50 or less.

On the other hand, in the glass material for molding of the present embodiment, when the glass is composed of C, SrO, BaO, and ZnO can be introduced in small amounts to improve the stability of the glass and also have the effect of increasing the refractive index. Therefore, from the viewpoint of maintaining low dispersibility, the mass ratio ((ZnO+SrO+BaO)/(MgO+CaO)) is preferably 0.17 or more, and the more preferable order is 0.18 or more, 0.19 or more, 0.20 or more, 0.25 Above, above 0.30.

In the glass material for molding of this embodiment, when the glass composition is C, the _{total content of Li 2} O, Na ₂ O, and K ₂ O is the mass ratio with respect to the total content of Nb ₂ O ₅ and TiO _{2 [(Li 2} O The lower limit of +Na ₂ O +K ₂ O)/(Nb ₂ O ₅ +TiO ₂ )] is preferably 0.001, and the more preferred order is 0.01, 0.02, 0.03, 0.04. In addition, the upper limit of the mass ratio is preferably 1.00, and the more preferable order is 0.50, 0.30, 0.20, 0.10, 0.08, 0.06.

In the glass composition C, the mass ratio [(Li ₂ O+Na ₂ O+K ₂ O)/ (Nb ₂ O ₅ +TiO ₂ )] is preferably within the above range.

In the glass material for molding of this embodiment, when the glass is composed of C, it contributes to dispersibility. If TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O _{3 are} combined with Comparing La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ , TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O ₃ have a tendency to make glass lower dispersion, while La ₂ O ₃ , Gd ₂ O ₃ and Y ₂ O ₃ have a tendency to make glass more dispersible. From the viewpoint of obtaining the required dispersibility, the _{total content of La 2} O ₃ , Gd ₂ O ₃ and Y ₂ O _{3 is} relative to the total of TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O ₃ The mass ratio of content ((La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ )/(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), preferably more than 0.00, the more preferred order is 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, and more preferably 1.00 or less, more preferably 0.90 or less, 0.80 or less, 0.70 Below, 0.60 or less, 0.50 or less, 0.45 or less, 0.40 or less, 0.35 or less, 0.32 or less.

Molding glass material of the present embodiment, when the glass composition C, TiO ₂ content of the _{TiO 2, Nb 2 O 5,} Ta 2 O 5, mass of WO ₃ and Bi ₂ O ₃ total content ratio of (TiO ₂ /(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), from the viewpoint of high refractive index and low specific gravity, it is preferably 0.00 or more, and more preferably in the order of more than 0.00, 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.15 or more, 0.20 or more, 0.25 or more, 0.30 or more. On the other hand, from the viewpoint of suppressing glass coloration and improving glass stability, it is preferably 1.00 or less, and more preferably the order is less than 1.00, 0.95 or less, 0.90 or less, 0.85 or less, 0.80 or less, 0.75 or less, 0.73 or less , 0.60 or less, 0.50 or less, 0.45 or less, 0.40 or less.

In the glass material for molding of this embodiment, in the case of glass composition C, the mass ratio of the _{Nb 2} O ₅ content to the total content of TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O _{3 (} Nb ₂ O ₅ /(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), from the viewpoint of improving partial dispersion characteristics, it is preferably 0.00 or more, more preferably in order More than 0.00, 0.01 or more, 0.05 or more, 0.10 or more, 0.15 or more, 0.20 or more, 0.21 or more, 0.22 or more, 0.23 or more, 0.24 or more, 0.25 or more, 0.26 or more, 0.27 or more. On the other hand, in order to improve the thermal stability of the glass and improve the reheating devitrification, it is preferably 1.00 or less, and the more preferable sequence is less than 1.00, 0.99 or less, 0.98 or less, 0.97 or less, 0.96 or less, and 0.95 or less. , 0.94 or less, 0.93 or less, 0.92 or less, 0.91 or less, 0.85 or less, 0.80 or less, 0.75 or less, 0.70 or less, 0.66 or less.

Molding glass material of the present embodiment, when the glass composition C, Ta ₂ O ₅ content of the _{2 O 5, 2 O 5,} 2 O 3 the total content of TiO _2, Nb Ta WO ₃ and Bi mass ratio ( Ta ₂ O ₅ /(TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), from the viewpoint of reducing the cost of glass raw materials and lowering the specific gravity, it is preferably less than 1.00, more The preferred order is below 0.80, below 0.60, below 0.40, below 0.30, below 0.20, below 0.10, and more preferably below 0.

In the glass material for molding of this embodiment, when the glass composition is C, it belongs to TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O ₃ which are high refractive index and high dispersion components. ₃ and Bi ₂ O _{3 have a} greater effect on increasing the specific gravity. So, from the much lower proportion of view, WO ₃ content with respect to the mass of _{TiO 2, Nb 2 O 5,} Ta 2 O 5, 2 O 3 the total content of WO ₃ and Bi ratio _{(WO 3 / (TiO 2 +} Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), preferably 1.00 or less, and more preferably in the order of 0.80 or less, 0.60 or less, 0.40 or less, 0.30 or less, 0.20 or less, 0.10 or less, especially The best department is 0. On the situation From the same viewpoint, the glass composition C, Bi ₂ O ₃ content with respect to _{TiO 2, Nb 2 O 5,} Ta 2 O 5, 2 O 3 the total content of WO ₃ and Bi mass ratio of (Bi ₂ O ₃ / (TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), preferably 1.00 or less, and more preferably in the order of 0.80 or less, 0.60 or less, 0.40 or less, 0.30 or less, 0.20 or less , 0.10 or less, especially preferred is 0.

In the glass material for molding of this embodiment, when the glass composition is C, Li ₂ O ₃ , La ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O ₃ have the effect of increasing the refractive index. On the other hand, SiO ₂ , B ₂ O ₃ , Na ₂ O, K ₂ O, MgO, CaO, SrO, BaO, and ZnO have a tendency to lower the refractive index. From the viewpoint of higher refractive index, the _{total content of SiO 2} , B ₂ O ₃ , Na ₂ O, K ₂ O, MgO, CaO, SrO, BaO, and ZnO is relative to Li ₂ O ₃ , La ₂ O ₃ , The mass ratio of the total content of Gd ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ and Bi ₂ O _{3 ((SiO 2} +B ₂ O ₃ +Na ₂ O+K ₂ O+MgO+CaO+SrO+BaO+ZnO)/(Li ₂ O+La ₂ O ₃ +Gd ₂ O ₃ +Y ₂ O ₃ +ZrO ₂ +TiO ₂ +Nb ₂ O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ )), preferably 0.12 or more, and more preferably the order is 0.15 or more, 0.20 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, and , More preferably 2.83 or less, and more preferably 2.80 or less, 2.60 or less, 2.40 or less, 2.20 or less, 2.00 or less, 1.80 or less, 1.70 or less, 1.60 or less, 1.50 or less, 1.40 or less, 1.30 or less, 1.26 or less, 1.25 Below, 1.24 or less.

In the glass material for molding of this embodiment, in the case of glass composition C, although TiO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ , Bi ₂ O ₃ and ZrO ₂ have the effect of increasing the refractive index of the glass, If the ZrO ₂ content is too large, the glass meltability tends to decrease. It From the above viewpoint, ZrO ₂ content of the _{TiO 2, Nb 2 O 5,} Ta 2 O 5, the quality of WO _3, Bi ₂ O ₃ and ZrO ₂ total content ratio _{(ZrO 2 / (TiO 2 +} Nb 2 O ₅ +Ta ₂ O ₅ +WO ₃ +Bi ₂ O ₃ +ZrO ₂ )), preferably 0.00 or more, more preferably 0.01 or more, 0.02 or more in order, more preferably 0.17 or less, more preferably The sequence system is below 0.16, below 0.15, below 0.14, and below 0.13.

In the glass material for molding of the present embodiment, when the glass composition is C, although TiO ₂ , Nb ₂ O ₅ , WO ₃ and ZnO have a tendency to increase the refractive index and make the glass more dispersible, if a large amount of these is contained In the case of glass, there will be a tendency for the thermal stability of the glass to decrease. On the other hand, MgO, CaO, SrO, and BaO have a tendency to lower the dispersibility of the glass and have an effect of improving thermal stability. If these are contained in a large amount, the refractive index tends to decrease. It From the above viewpoint MgO, CaO, SrO and BaO in total content, with respect to the mass of TiO _2, Nb ₂ O _5, the total content of WO ₃ and ZnO ratio ((MgO + CaO + SrO + BaO) / (TiO 2 + Nb ₂ O ₅ +WO ₃ +ZnO)), preferably 0.10 or more, and more preferably in the order of 0.15 or more, 0.20 or more, 0.25 or more, 0.26 or more, 0.27 or more, 0.28 or more, 0.29 or more, 0.30 or more, 0.31 or more , 0.32 or more, more preferably 1.50 or less, and more preferably the order is 1.30 or less, 1.20 or less, 1.10 or less, 1.00 or less, 0.95 or less, 0.90 or less, and 0.87 or less.

In the glass material for molding of this embodiment, when the glass composition is C, the TiO ₂ content is preferably 0.00% or more, and more preferably, the order is more than 0.00%, 0.50% or more, 1.00% or more, 1.50% or more, 2.00 % Or more, 2.50% or more, 3.00% or more, 3.50% or more, 4.00% or more, and more preferably 50.00% or less, more preferably, 45.0% or less, 40.00% or less, 38.00% or less, 36.00% or less, 35.00% or less, 34.00% or less, 32.00% or less, 31.00% or less, 30.00% or less, 29.50% or less, 29.00% or less. The _{content of TiO 2} within the above range is preferable from the viewpoint of achieving better optical constants and reducing the cost of glass raw materials.

In the glass material for molding of the present embodiment, when the glass is composed of C, the Nb ₂ O ₅ content is preferably 0.00% or more, and more preferably, the order is more than 0.00%, 1.00% or more, 2.00% or more, and 3.00% or more. , 4.00% or more, 5.00% or more, 6.00% or more, 7.00% or more, 8.00% or more, 9.00% or more, 10.00% or more, 10.50% or more. In addition, the Nb ₂ O ₅ content is preferably 60.00% or less, and the more preferable order is 58.00% or less, 56.00% or less, 54.00% or less, 52.00% or less, 50.00% or less, 49.00% or less, 48.00% or less, 47.00% Below, 46.00% or less, 45.00% or less, 44.00% or less. The _{content of Nb 2} O ₅ within the above range is preferable from the viewpoints of achieving better optical constants, lower specific gravity, and improving partial dispersion characteristics.

In the glass material for molding of this embodiment, in the case of the glass composition C, the Ta ₂ O ₅ content can be set to 0.00% or more. In addition, the _{content of Ta 2} O _{5 is} preferably 5.00% or less, and a more preferable order is 4.00% or less, 3.00% or less, 2.00% or less, 1.00% or less, and 0.50% or less. The _{content of Ta 2} O ₅ within the above-mentioned range is preferable in terms of improving the thermal stability of the glass, improving the melting property, and lowering the specific gravity.

In the glass material for molding of this embodiment, in the case of the glass composition C, the WO ₃ content can be set to 0.00% or more. In addition, the WO ₃ content is preferably 5.00% or less, and more preferably, the order is 4.00% or less, 3.00% or less, 2.00% or less, 1.00% or less, and 0.50% or less in this order. The WO ₃ content within the above range is preferable from the viewpoints of increasing glass transmittance, improving partial dispersion characteristics, and lowering specific gravity.

In the glass material for molding of this embodiment, in the case of the glass composition C, the Bi ₂ O ₃ content can be set to 0.00% or more. In addition, the Bi ₂ O ₃ content is preferably 5.00% or less, and more preferably, the order is 4.00% or less, 3.00% or less, 2.00% or less, 1.00% or less, and 0.50% or less. The _{content of Bi 2} O ₃ within the above range is preferable from the viewpoints of enhancing the thermal stability of the glass, improving the partial dispersion characteristics, and lowering the specific gravity.

In the glass material for molding of the present embodiment, in the case of glass composition C, although GeO ₂ has an effect of increasing the refractive index, it is a very high unit price component. From the viewpoint of suppressing the glass manufacturing cost, the GeO ₂ content can be set to 0.00% or more and 2.00% or less, and the more preferable order is 1.50% or less, 1.00% or less, and 0.50% or less.

In the glass material for molding of the present embodiment, in the case of the glass composition C, in addition to the above-mentioned components, one or more of _{P 2} O ₅ , Al ₂ O _{3 and the like may be contained.} The _{content of P 2} O ₅ can be set to 0.00% or more, and preferably 10.00% or less, and the more preferable order is 8.00% or less, 6.00% or less, 4.00% or less, 2.00% or less, 1.00% or less, 0.50% or less . The _{content of P 2} O ₅ within the above range is preferable from the viewpoint of enhancing the thermal stability of the glass and improving the partial dispersion characteristics. The _{content of Al 2} O ₃ can be set to 0.00% or more, and preferably 10.00% or less, and the more preferable order is 8.00% or less, 6.00% or less, 4.00% or less, 2.00% or less, 1.00% or less, 0.50% or less . The _{content of Al 2} O ₃ within the above range is preferable from the viewpoint of enhancing the devitrification resistance and thermal stability of the glass.

Pb, As, Cd, Tl, Be, and Se are respectively toxic. Therefore, it is best not to contain these elements, that is, it is better not to introduce these elements into the glass as glass components. U, Th, and Ra are all radioactive elements. Therefore, it is best not to contain these elements, that is, it is better not to introduce these elements into the glass as glass components. V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Ce are the types that will increase the coloring of the glass or become the source of fluorescence , It is best not to be an element contained in the glass for optical components. Therefore, it is best not to contain these elements, that is, it is better not to introduce these elements into the glass as glass components.

Sb and Sn are arbitrarily addable elements with clarifying agent function. When the amount of Sb added is converted into Sb ₂ O ₃ and the _{total content of glass components other than Sb 2} O ₃ is set to 100% by mass, it is preferably in the range of 0 to 0.11% by mass, more preferably 0.01 to The range of 0.08% by mass, and the particularly preferred system is set to the range of 0.02 to 0.05% by mass. When the amount of Sn added is converted to SnO ₂ and the _{total content of glass components other than SnO 2} is set to 100% by mass, it is preferably in the range of 0 to 0.50% by mass, more preferably in the range of 0 to 0.20% by mass , Special best system is set to 0% by mass.

＜Glass properties＞ (Refractive index nd) In the glass material for molding of the present embodiment, when the glass composition is C, it can be a glass with a high refractive index. In the case of the glass composition C, the refractive index nd is preferably 1.860 or more, and the more preferable order is 1.865 or more, 1.870 or more, 1.875 or more, 1.880 or more, 1.885 or more, 1.890 or more, 1.895 or more, and 1.900 or more. Moreover, the refractive index nd system is set to 1.950 or less, 1.945 or less, 1.940 or less, 1.935 or less, 1.930 or less, or 1.925 or less, for example. In the present invention and this specification, "refractive index" means "refractive index nd".

(Abbe value νd) The Abbe number νd represents the value of the dispersive correlation property, and is represented by νd=(nd-1)/(nF-nC) using the respective refractive indexes nd, nF, and nC of the d-line, the F-line, and the C-line. In the glass material for molding of the present embodiment, when the glass composition is C, from the viewpoint of the usefulness of the material for optical elements, the Abbe value νd is preferably 22.00 or more, and more preferably, the order is 22.50 or more, 23.00 or more, Above 23.50, above 24.00, above 24.20, above 24.40, above 24.60, above 24.70, above 24.80, above 25.00, above 25.50, above 25.60, above 25.80, above 26.00. From the same point of view, the Abbe value νd is preferably 30.00 or less, and the more preferable order is 29.50 or less, 29.00 or less, 28.50 or less, 28.40 or less, 28.30 or less, 28.20 or less, 28.10 or less, 28.00 or less, 27.90 or less, 27.80 or less. Below, 27.70 or less.

Furthermore, in the glass material for molding of this embodiment, when the glass is composed of C, from the viewpoint of the usefulness of the material for optical elements, it is preferable that the refractive index nd and the Abbe number νd satisfy one of the following relational expressions: above: nd≧-0.0025νd+1.925 nd≧-0.0025νd+1.935 nd≦-0.0025νd+1.995 nd≦-0.0025νd+2.005

(Specific gravity d) The optical element constituting the optical system determines the refractive power by using the refractive index of the glass constituting the optical element and the curvature of the optical function surface of the optical element (the entrance and exit surface of the light to be controlled). If the curvature of the optical function surface is to be increased, the thickness of the optical element will also increase. As a result, the optical element becomes heavy. In contrast, if a glass with a higher refractive index is used, a larger refractive power can be obtained even if the curvature of the optical function surface is not increased. According to the above, if the refractive index can be increased while suppressing the increase in the specific gravity of the glass, an optical element with a certain refractive power can be lightened. From the above point of view, in the glass material for molding of the present embodiment, when the glass is composed of C, the specific gravity d is preferably 4.100 or less, and the more preferable order is 4.095 or less, 4.090 or less, 4.085 or less, 4.080 or less, 4.050 Below, 4.000 or less, 3.995 or less, 3.990 or less, 3.985 or less. From the viewpoint that the lower the specific gravity, the lighter the weight of the optical element, it is better to have a lower specific gravity, and the lower limit of the relevant specific gravity is not particularly limited. In one form, the specific gravity can be 3.400 or higher, 3.450 or higher, 3.500 or higher, 3.550 or higher, 3.600 or higher, 3.650 or higher, 3.700 or higher, or 3.750 or higher.

(d/nd) From the same viewpoint as the above-mentioned related specific gravity d, the quotient (d/nd) of the specific gravity d divided by the refractive index nd in the glass material for molding of the present embodiment is preferably 4.35 when the glass is composed of C. Below, the more preferable order is 4.00 or less, 3.50 or less, 3.00 or less, 2.90 or less, 2.80 or less, 2.70 or less, 2.60 or less, 2.50 or less, 2.40 or less, 2.30 or less, 2.20 or less, and 2.15 or less. From the viewpoint that the smaller the (d/nd) value, the lighter the optical element, the smaller the (d/nd) value is preferable, and the lower limit of the correlation (d/nd) is not particularly limited. One aspect of the (d/nd) system can be, for example, 1.74 or more, 1.76 or more, 1.78 or more, 1.80 or more, 1.82 or more, 1.84 or more, 1.85 or more, 1.86 or more, 1.87 or more, 1.88 or more, 1.89 or more, 1.90 or more, 1.91 or higher, 1.92 or higher, 1.93 or higher, 1.94 or higher, or 1.95 or higher.

(Coloring degree λ5) In the glass material for molding of the present embodiment, when the glass composition is C, the light transmittance of the relevant glass, specifically, suppresses the increase of the wavelength of the light absorption end on the short-wavelength side, and can be evaluated by the coloring degree λ5. The so-called "coloring degree λ5" refers to the wavelength at which the spectral transmittance (including surface reflection loss) of glass with a thickness of 10 mm from the ultraviolet region to the visible region becomes 5%. In the case of glass composition C, the so-called "spectral transmittance" is, for example, in detail, it is obtained when a glass sample with a thickness of 10.0±0.1 mm and a plane parallel to the direction to be polished is used, and light is incident on the polished surface from a vertical direction Spectral transmittance, that is, when the intensity of light incident on the glass sample is Iin, and the intensity of light penetrating the glass sample is Iout, it is referred to as Iout/Iin. Based on the degree of coloring λ5, the absorption end on the short-wavelength side of the spectral transmittance can be quantitatively evaluated. When bonding the lenses with an ultraviolet curable adhesive to produce a doublet lens, the adhesive is irradiated with ultraviolet rays through an optical element to harden the adhesive. From the viewpoint of efficient implementation of UV-curable adhesive curing, the absorption end on the short-wavelength side of the spectral transmittance is preferably in the shorter wavelength range. As a quantitative evaluation index for the absorption end on the short wavelength side, the coloring degree λ5 can be used. In the case of glass composition C, it is preferable to exhibit λ5 of 400 nm or less. The more preferable order of λ5 is 395nm or less, 390nm or less, 385nm or less, and 380nm or less. The lower the λ5 system, the better, and the lower limit is not particularly limited.

(Glass transition temperature Tg) In the glass material for molding of the present embodiment, when the glass composition is C, the glass transition temperature Tg is preferably 560°C or higher from the viewpoint of machinability. The glass with a higher glass transition temperature tends to be less susceptible to damage when subjected to glass machining such as cutting, cutting, grinding, and grinding, so it is preferable. From the viewpoint of machinability, the glass transition temperature Tg is more preferably 570°C or higher, and more preferably 580°C or higher, 590°C or higher, and 600°C or higher in this order. On the other hand, from the viewpoint of reducing the burden on the annealing furnace and the forming mold, the glass transition temperature Tg is preferably 800°C or lower, and the more preferable order is 790°C or lower, 780°C or lower, 770°C or lower, and 760°C or lower. , Below 750℃, below 740℃.

The glass transition temperature Tg is determined as follows. In the differential scanning calorimetry analysis, if the glass sample is heated up, an endothermic behavior accompanied by a change in specific heat will appear, that is, an endothermic peak will appear, and if the temperature rises further, a heating peak will appear. In the differential scanning calorimetry analysis, the horizontal axis is temperature and the vertical axis is the differential scanning calorie curve (DSC curve) corresponding to the heat absorption of the sample. In this curve, the tangent line where the slope at which the endothermic spike appears from the baseline is the largest, and the intersection point with the baseline is set as the glass transition temperature Tg. When measuring the glass transition temperature Tg, the glass can be fully crushed with a mortar or the like as a sample, and then a differential scanning calorimeter can be used, and the temperature rise rate is 10°C/min.

(Liquid phase temperature) The thermal stability of glass includes the devitrification resistance when the glass melt is molded, and the devitrification resistance when the cured glass is reheated. The devitrification resistance of the relevant glass melt during molding can be determined by using the liquidus temperature LT as an index. It can be said that the lower the liquidus temperature, the better the devitrification resistance. In order to prevent devitrification of glass with a higher liquidus temperature, the temperature of the glass melt (ie molten glass) must be kept at a high temperature. However, for example, volatile components will volatilize and the crucible will be corroded, especially for precious metal crucibles. The glass will be colored due to the dissolution of precious metal ions in the glass melt, and the viscosity during molding will decrease, making it difficult to mold into highly homogeneous glass. Therefore, in the case of glass composition C, the liquidus temperature is preferably 1400°C or lower, and the more preferable order is 1370°C or lower, 1340°C or lower, 1310°C or lower, 1280°C or lower, 1270°C or lower, 1260°C or lower, 1250°C in order. the following. In addition, the liquidus temperature system can be set to, for example, 1000°C or higher, 1050°C or higher, or 1100°C or higher, but may be higher than the value exemplified here.

The "liquid phase temperature" in the present invention and this specification can be obtained according to the following method. Using a differential scanning calorimeter, while flowing nitrogen at a flow rate of 0.3L/min, about 0.02ml of the crushed glass sample is heated in a nitrogen environment at a heating rate of 10°C/min to 1350°C, when the heat is generated during the heating process When crystals in glass melt in a temperature range higher than the glass transition temperature or crystallization temperature, the end point of the generated endothermic peak is set as the liquidus temperature. Fig. 1 shows a schematic diagram of a differential scanning calorie curve (DSC curve). The horizontal axis indicates the temperature, the more to the right on the horizontal axis, the higher the temperature, and the more to the left, the lower the temperature. The vertical axis corresponds to the heat generation and heat absorption of the sample. The upper side of the baseline (dotted line) is heat generation, and the lower side is heat absorption. The precipitation of crystals during the heating process corresponds to the exothermic peak, and the melting of the precipitated crystals corresponds to the endothermic peak. The temperature at which the crystal melts and melts is the liquidus temperature. The liquidus temperature is the temperature of the intersection point of the tangent of the endothermic peak on the high-temperature side and the baseline.

(Manufacturing of glass materials) The glass of the embodiment of the present invention can be prepared by blending glass raw materials so as to have the above-mentioned predetermined composition, and then using the blended glass raw materials. For example, a plurality of compounds are blended and fully mixed into a master batch, and the master batch is put into a quartz crucible or a platinum crucible to perform rough melting. The melt obtained by rough melting is cooled and pulverized to produce glass chips. The glass scraps are put into a platinum crucible, heated and remelted (remelted) to become molten glass. After cooling, clarification, and homogenization are performed, the molten glass is cast in a temperature adjusted to a temperature Tx that is less than Tg. In the mold (step 1), the temperature Tx is maintained (step 2). Then, in order to reduce the strain point temperature of the glass, cooling is performed at -30°C/hr for 4 hours (Step 3), and the glass is cooled at a rate of gradual cooling to the extent that the glass does not appear to be cracked. Temperature (Step 4).

In addition, there are no special restrictions on the compound used in the preparation of the masterbatch before the required glass components can be introduced into the glass according to the required content. Examples of such compounds include: oxides, carbonates, Nitrate, hydroxide, fluoride, etc.

Hereinafter, steps 1 to 4 will be described.

(step 1) Step 1. The molten glass is cast into a mold whose temperature has been adjusted to reach a temperature Tx that is less than the glass transition temperature Tg. By controlling the temperature of the molten glass as described above, the thermal energy applied to the glass can be suppressed, and the movement of atoms in the glass can be suppressed. As a result, the movement of atoms can be regulated before the structural factors inside the glass such as the bonding distance between the atoms in the glass and the bonding angles are homogenized. Therefore, by maintaining a messy glass structure like a molten state, a glass material with excellent stability during reheating can be obtained.

In addition, the melting glass temperature before step 1 is usually the liquidus temperature of the glass to the melting temperature of the glass. In addition, in step 1, the glass temperature when the molten glass is cast into the mold is the temperature when the glass is melted, and is about 1500°C to 1100°C, preferably in the range of 1400°C to 1200°C. Therefore, in step 1, the molten glass will be cooled as it is cast into the mold. At this time, the cooling is usually performed by using the air to cool. However, if the cooling rate is not fast enough, a part of the inside of the glass may become highly viscous or solidify with no fluidity. As a result, the homogenization of the glass will be hindered, and there will also be a concern that the glass will crack or break. Therefore, the lower limit of the cooling rate in step 1 is preferably about 1°C/sec, and more preferably, the order is 3°C/sec and 6°C/sec in this order. The upper limit of the cooling rate is preferably 20°C/sec, and more preferably, the order is 15°C/sec, 12°C/sec, and 10°C/sec in this order.

(Step 2) In step 2, the molten glass is maintained according to the temperature Tx. The holding temperature Tx of step 2 is preferably less than the glass transition temperature Tg, and the upper limit is preferably in order of Tg-1°C, Tg-5°C, Tg-10°C, Tg-15°C, Tg-20°C. By setting the upper limit of the holding temperature Tx to the above range, the disorder of the glass structure can be improved, and a glass material having excellent stability during reheating can be obtained.

The lower limit of the holding temperature Tx in step 2 is preferably Tg-100°C, and more preferably the order is Tg-90°C, Tg-80°C, Tg-70°C, Tg-60°C, Tg-50°C. The Tx of the best system is not excessively lower than the strain point, and the best system is above the strain point. By setting the lower limit of the holding temperature Tx to the above-mentioned range, excessive internal strain of the glass can be removed, so that deterioration of glass workability can be suppressed in a later step, or the glass block material can be prevented from being damaged. When the subsequent steps are processes that have nothing to do with the deterioration of glass workability, there is no special requirement for the lower temperature limit of step 2.

The holding time of step 2 is to homogenize the high temperature glass cooled from the molten state. The thicker the glass and the larger the volume of the glass, the longer it will take. It is preferably more than 10 minutes. It is 20 minutes or more, or 30 minutes or more. From the viewpoint of productivity and the viewpoint of maintaining the thermal stability of the glass, the upper limit of the holding time is less than 3 hours, and the more preferable order is less than 2 hours, less than 1.5 hours, or less than 1.0 hour. If the holding time is too long, the disordered state of the atomic arrangement in the molten state cannot be maintained, and the structural ordering of the atomic arrangement reduces the thermal stability of the glass and also tends to increase the _{α max.}

(Step 3) Step 3. The glass system can be cooled down at -30°C/hr for 4 hours so that the strain point temperature can be reliably lowered during the gradual cooling. The time required for this cooling is when the temperature Tx is higher than the strain point, preferably 4 hours or more, more preferably 5 hours or more, particularly preferably 6 hours or more. If the temperature Tx is lower than the strain point, it can also be set to less than 4 hours.

(Step 4) Step 4, the glass is cooled to a temperature at which the glass can be taken out of the furnace at a gradual cooling rate that does not appear to be cracked. The gradual cooling rate in step 4 is preferably less than about -50°C/hr, and more preferably set to about -10°C/hr or -30°C/hr. If it is less than -1°C/hr, it may hinder productivity. In addition, the temperature of the glass that can be taken out of the furnace varies according to the heat insulation conditions outside the furnace, and is preferably about 100°C or less, and more preferably, the order is 80°C or less, 60°C or less, 40°C or less, and 20°C or less in this order. If expressed in terms of the difference from room temperature, the upper limit of the glass temperature outside the furnace can be taken out, preferably room temperature +50°C, and the more preferred sequence is room temperature +40°C, room temperature +30°C, and room temperature +20°C , Room temperature +10℃. The lower limit of the temperature of the glass that can be taken out of the furnace is set to room temperature.

When the glass is gradually cooled, it is only necessary to adopt a known method (for example, a gradual cooling furnace that can be controlled by a temperature program) that can obtain the above-mentioned temperature distribution.

By setting the cooling rate of step 1 and the holding temperature Tx of step 2 within the above-mentioned ranges, a glass material with high disorder of the glass structure and excellent stability during reheating can be obtained. In addition, by cooling and gradually cooling the glass as in Steps 3 and 4, the strain of the glass can be removed, so that the workability of the glass can be maintained in the subsequent steps.

The optical glass system of the embodiment of the present invention can directly use the glass material for molding of the embodiment of the present invention.

(Manufacturing of optical components, etc.) When an optical element is manufactured using the glass material for molding of the embodiment of the present invention, a known method may be used. For example, at the time of manufacturing the above-mentioned glass material, molten glass is poured into a mold and molded into a plate shape to produce the glass material for molding of the present invention. The obtained glass material is appropriately cut, ground, and ground to produce a molding precursor (also called "slice") with a size and shape suitable for molding after reheating. The slices are heated and softened, and are molded using a known method (reheat stamping, round bar molding, extrusion molding, etc.) to produce an optical element blank that is approximately the shape of an optical element. The optical element blank is annealed, and then cut, ground, polished, etc. are performed by a known method to produce an optical element.

The optical function surface of the manufactured optical element can also be coated with anti-reflection film, total reflection film, etc. according to the purpose of use.

According to an aspect of the present invention, an optical element composed of the above-mentioned optical glass can be provided. The types of optical elements can be exemplified by lenses such as spherical lenses and aspheric lenses; diffractive gratings and diffraction gratings. The shape of the lens can be exemplified by various shapes such as a biconvex lens, a plano-convex lens, a bi-concave lens, a plano-concave lens, a convex meniscus lens, and a concave meniscus lens. The optical element can be manufactured by a method including a step of processing a glass molded body composed of the above-mentioned optical glass. Examples of processing systems include: cutting, cutting, rough grinding, fine grinding, and grinding. When performing such processing, by using the above-mentioned glass, damage can be reduced and high-quality optical components can be supplied stably.

Second Embodiment The molding glass material of the second embodiment is the maximum linear expansion coefficient α _max , the average linear expansion coefficient α _100-300 at 100 to 300°C, and the total content _{of SiO 2} and ZrO ₂ expressed in mass% [ SiO ₂ +ZrO ₂ ], which satisfies the following formula (4): α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦264 ・・・(4)

In the glass material for molding of the second embodiment, the maximum linear expansion coefficient α _max , the average linear expansion coefficient α _100-300 at 100 to 300°C, and the total content _{of SiO 2} and ZrO ₂ expressed in mass% _{[SiO 2} + ZrO ₂ ] satisfies the following formula (4), more preferably satisfies the following formula (5), and particularly preferably satisfies the following formula (6). By satisfying the following formula, a molding glass material with excellent stability during reheating can be obtained. α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦264 ・・・(4) α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦260 ・・・(5) α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦255 ・・・(6)

The maximum linear expansion coefficient α _max and the average linear expansion coefficient α _100-300 are controlled by adjusting the conditions for cooling the molten glass in the manufacturing steps of the glass material described later.

The maximum linear expansion coefficient α _max and the average linear expansion coefficient α _100-300 can be measured in the same manner as in the first embodiment.

In the molding glass material of the second embodiment, the maximum linear expansion coefficient α _max and the total content _{of SiO 2} and ZrO ₂ expressed in mass% _{[SiO 2} +ZrO ₂ ] preferably satisfy the following formula (1), The better system satisfies the following formula (2), and the particularly best system satisfies the following formula (3). From the viewpoint of obtaining a glass material for molding with excellent stability during reheating, it is preferable to satisfy the following formula: α _max ×[SiO ₂ +ZrO ₂ ]≦27900 ・・・(1) α _max ×[SiO ₂ +ZrO ₂ ]≦27500 ・・・(2) α _max ×[SiO ₂ +ZrO ₂ ]≦27000 ・・・(3)

The maximum linear expansion coefficient α _max is in the manufacturing step of the glass material described later, and can be controlled by adjusting the conditions for cooling the molten glass.

In the glass material for molding of the second embodiment, the characteristics and glass composition system other than the above can be the same as those in the first embodiment. In addition, the manufacturing of the glass material and the manufacturing of optical elements and the like related to the second embodiment can also be the same as those of the first embodiment.

Third Embodiment In the molding glass material of the third embodiment, the maximum linear expansion coefficient α _max is smaller than the maximum linear expansion coefficient α _max (Tg), and the maximum linear expansion coefficient α _max (Tg) is The glass material for molding is soaked according to the glass transition temperature Tg, then cooled at -30°C/hr for 4 hours, and then left to cool to obtain the maximum linear expansion coefficient α _max (Tg) of the glass material.

In the glass material for molding of the third embodiment, the maximum linear expansion coefficient α _max is smaller than that after the glass material for molding is soaked at the glass transition temperature Tg, and then cooled at -30°C/hr for 4 hours , And then the maximum linear expansion coefficient α _max (Tg) of the glass material obtained by cooling. However, the maximum linear expansion coefficient α _max may be slightly larger than the above-mentioned maximum linear expansion coefficient α _max (Tg). Therefore, the difference between α _max and α _max (Tg) [α _max (Tg)-α _max ], if ^{expressed in the unit of 10 -7} ·℃ ^{-1, the} first digit of the integer is preferably -9 or higher, and the order is better. Sequential system -4 and above, 0 and above, 5 and above, 10 and above, 20 and above, 40 and above, 60 and above, 80 and above, 100 and above, 120 and above, 140 and above, 160 and above, 180 and above, 200 and above, 250 and above, 300 above. In addition, the upper limit of the difference is not particularly limited, but it is usually α _max (Tg), and preferably about α _max (Tg)-100.

In the glass material for molding of the third embodiment, the _{method of measuring the maximum value α max} (Tg) is the same as that of the first embodiment.

In the glass material for molding of the third embodiment, the maximum linear expansion coefficient α _max and the total content _{of SiO 2} and ZrO ₂ expressed in mass% _{[SiO 2} +ZrO ₂ ] preferably satisfy the following formula (1), The better system satisfies the following formula (2), and the particularly best system satisfies the following formula (3). From the viewpoint of obtaining a glass material for molding with excellent stability during reheating, it is best to satisfy the following formula: α _max ×[SiO ₂ +ZrO ₂ ]≦27900 ・・・(1) α _max ×[SiO ₂ +ZrO ₂ ]≦27500 ・・・(2) α _max ×[SiO ₂ +ZrO ₂ ]≦27000 ・・・(3)

The maximum linear expansion coefficient α _max is in the manufacturing step of the glass material described later, and can be controlled by adjusting the conditions for cooling the molten glass.

In the glass material for molding of the third embodiment, characteristics and glass composition systems other than the above can be made the same as those in the first embodiment. In addition, the manufacturing of the glass material and the manufacturing of optical elements and the like related to the third embodiment may be the same as those of the first embodiment. [Example]

Hereinafter, a more detailed description will be given of the application examples of the present invention. However, the present invention is not limited to the aspects shown in the embodiments.

(Example 1-1) A glass sample having the glass composition I shown in Table 1 (1) was prepared in the following procedure, and various evaluations were performed on the obtained glass sample. The results are shown in Tables 2(1) and 2(2).

[Manufacturing of glass samples] First, the raw material system prepares the oxides, hydroxides, carbonates, and nitrates corresponding to the components of the glass. The glass composition of the obtained optical glass becomes the composition I shown in Table 1 (1). After mixing, the raw materials are fully mixed. Put the prepared raw material (masterbatch) obtained in this way into a platinum crucible, heat at 1350℃~1450℃ for 2 hours to obtain molten glass, stir to homogenize, and then clarify, then cast the molten glass into the preheated Into a mold at an appropriate temperature and quenched (Step 1). The cast glass is held for 30 minutes at a holding temperature Tx that is 25°C lower than the glass transition temperature Tg (step 2). Then, cool to a temperature 120°C lower than the holding temperature Tx of step 2 at a rate of -30°C/hr (step 3), and then cool to room temperature in the furnace (step 4) to obtain a glass sample. The amount of glass here is 150 g.

Here, the holding temperature Tx of step 2 is the value rounded to the first decimal place of the glass transition temperature Tg (unit: °C) as the Tg of the glass sample, and then the value 25 °C lower than the temperature is set as the holding Temperature Tx. In Table 2(2), the difference between the rounded Tg corresponding to such a temperature difference and the holding temperature Tx is described. In this way, although the measured value of Tg varies somewhat, it can be set to the same holding temperature Tx, so that multiple samples can be held at one time, thereby improving the production efficiency of the glass of the present invention.

[Confirmation of glass composition] For the obtained glass samples, inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to determine the content of each glass component. The composition I was confirmed as shown in Table 1(1).

[Glass transition temperature Tg] The glass transition temperature Tg was measured using a differential scanning calorimeter (DSC3300SA) manufactured by NETZSCH JAPAN Co., Ltd. at a temperature increase rate of 10°C/min.

[Stability Test] After the obtained glass sample was confirmed by an optical microscope (100 times) that there was no foreign matter inside, it was cut and cut to obtain a sample of 11 mm×11 mm×10.5 mm. The sample was placed in a heat treatment furnace set to a temperature 200°C higher than Tg, heated, and taken out after 5 minutes, and the glass sample was cooled. The end of the cooled glass sample was optically polished, and then the inside of the glass sample was observed with an optical microscope (100 times). The number of crystals (bright spots) observed from the entire glass sample was counted and converted to the number per 1 g. The size of the crystal system is in the range of 1 to 300 μm. In addition, no cracks or lines were found in the glass sample.

[Coefficient of Linear Expansion] For the obtained glass samples, the average linear expansion coefficient was measured in accordance with the regulations of JOGIS08. The sample system is a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. In a state where a load of 98 mN is applied to the sample, the sample is heated at a constant rate of 4°C per minute, and the temperature and sample elongation are measured every 1 second. Between room temperature and yield point temperature (the temperature at which the sample falls and the extension stops apparently), when the extension of the sample becomes a maximum per unit temperature rise, the maximum value of the linear expansion coefficient at that temperature is set to α _max . In addition, α _max is the maximum value obtained by moving average processing using linear expansion coefficients from 31 measurement points. In addition, the average linear expansion coefficient of 100 to 300°C is defined as the average linear expansion coefficient α _100-300 .

Measure the maximum linear expansion coefficient α _{max and the maximum linear expansion coefficient α max} (Tg) of the glass when the holding temperature Tx in step 2 is set to the glass transition temperature, and calculate the difference Q: α _max (Tg)-α _max .

[Average Linear Expansion Coefficient α _L ] For the obtained glass samples, the average linear expansion coefficient was measured in accordance with the regulations of JOGIS16. The average linear expansion coefficient was measured using a thermomechanical analyzer (TMA4000SE) manufactured by NETZSCH JAPAN. The sample system uses a round rod with a length of 20 mm ± 0.5 mm and a diameter of 5 mm ± 0.5 mm. First, use liquid nitrogen to cool the sample temperature to below -80°C, and after keeping it for 20 minutes, start the measurement. During the measurement, while applying a load of 98 mN to the sample, the temperature and sample elongation were measured every 1 second while raising the temperature to 320°C at a constant rate of 4°C per minute. Let the average linear expansion coefficient of -30~70℃ be the average linear expansion coefficient α _L.

[Measurement of Optical Properties] For the obtained glass sample, the refractive index nd, ng, nF and nC, Abbe number νd, partial dispersion ratio Pg,F, and ΔPg,F were measured. The results are shown in Tables 2(1) and 2(2).

(i) Refractive index nd, ng, nF, nC and Abbe number νd For the above-mentioned glass sample, the refractive index nd, ng, nF, and nC were measured by the refractive index measurement method of Japanese Industrial Standards JIS B 7071-1, and the Abbe number νd was calculated according to the following formula. νd=(nd-1)/(nF-nC)

(ii) Partial dispersion ratio Pg, F, ΔPg, F Using the respective refractive indices ng, nF, and nC of the g-line, F-line, and c-line, the partial dispersion ratios Pg,F and ΔPg,F are calculated according to the following formula. Pg,F=(ng-nF)/(nF-nC) ・・・(13) ΔPg,F=Pg,F-(0.6483-0.001802×νd) ・・・(14)

[Evaluation of light penetration] (i)λτ80 Using glass samples with thicknesses of 2.0mm±0.1mm and 10.0mm±0.1mm, according to JOGIS17 (method for measuring the internal transmittance of optical glass), the spectral transmittance is measured in the wavelength range of 200~700nm. The wavelength at which the internal transmittance at a thickness of 10 mm becomes 80% is λτ80. The results are shown in Table 2(1).

(ii) λ70 For a glass sample with a thickness of 10.0mm±0.1mm, the spectral transmittance is measured in the wavelength range of 200~700nm. The wavelength at which the internal transmittance becomes 70% is set to λ70. The results are shown in Table 2(1).

[proportion] The specific gravity is determined by the Archimedes method. The results are shown in Table 2(1).

(Example 1-2) In the manufacture of the glass sample, except that the holding temperature Tx in step 2 was set to a temperature lower than the glass transition temperature Tg by 50° C., the glass samples were obtained in the same manner as in Example 1-1. Various evaluations were performed in the same manner as in Example 1-1.

(Example 1-3) In the manufacture of the glass sample, the glass sample was obtained in the same manner as in Example 1-1 except that the holding temperature Tx in step 2 was set to a temperature lower than the glass transition temperature Tg by 100°C. Various evaluations were performed in the same manner as in Example 1-1.

(Example 2-1) A glass sample having glass composition II shown in Table 1(1) was produced. In the manufacture of glass samples, except that the raw materials are prepared in a way to become glass composition II, and the holding temperature Tx in step 2 is set to a temperature lower than the glass transition temperature Tg by 60°C, the rest are all in accordance with Example 1- 1 Obtain glass samples in the same way. Various evaluations were performed in the same manner as in Example 1-1.

(Comparative Example 1-1) In the manufacture of the glass sample, except that the holding temperature Tx in step 2 was set to a temperature higher than the glass transition temperature Tg by 30°C, the glass sample was obtained in the same manner as in Example 1-1. Various evaluations were performed in the same manner as in Example 1-1.

(Comparative Example 1-2) In the manufacture of a glass sample, except that the holding temperature Tx in step 2 was set to the glass transition temperature Tg, the glass sample was obtained in the same manner as in Example 1-1. Various evaluations were performed in the same manner as in Example 1-1. In addition, the maximum value of the linear expansion coefficient of Comparative Example 1-2 was set to α _max (Tg), and the comparison was made with the maximum value of the linear expansion coefficient α _{max of} Examples 1-1, 1-2, and 1-3.

(Comparative example 1-3) In the manufacture of the glass sample, the glass sample was obtained in the same manner as in Example 1-1 except that the holding time of step 2 was set to 72 hours. Various evaluations were performed in the same manner as in Example 1-1. In addition, although the glass can be obtained in Comparative Examples 1-3, significant devitrification occurred during the stability test. In addition, the refractive index nd, Abbe number νd, partial dispersion ratio Pg,F, and ΔPg,F could not be measured.

(Comparative Example 2-1) In the manufacture of a glass sample, except that the holding temperature Tx in step 2 was set to the glass transition temperature Tg, the glass sample was obtained in the same manner as in Example 2-1. Various evaluations were performed in the same manner as in Example 2-1. In addition, the maximum linear expansion coefficient of Comparative Example 2-1 was set to α _max (Tg) and compared with the maximum linear expansion coefficient α _{max of} Example 2-1.

(Example 3-1) A glass sample having the glass composition III shown in Table 1(2) was produced. In the manufacture of glass samples, except that the raw materials are prepared in a way to become glass composition III, and the holding temperature Tx in step 2 is set to a temperature lower than the glass transition temperature Tg by 60°C, the rest are all in accordance with Example 1- 1 Obtain glass samples in the same way. Various evaluations were performed in the same manner as in Example 1-1.

(Example 3-2) A glass sample having the glass composition III shown in Table 1(2) was produced. In the manufacture of glass samples, except that the raw materials are prepared in a way to become glass composition III, and the holding temperature Tx in step 2 is set to a temperature lower than the glass transition temperature Tg by 100°C, the rest are all in accordance with Example 1- 1 Obtain glass samples in the same way. Various evaluations were performed in the same manner as in Example 1-1.

(Example 4-1) A glass sample having the glass composition IV shown in Table 1(3) was produced. In the manufacture of glass samples, except that the raw materials are prepared in a way to become glass composition III, and the holding temperature Tx in step 2 is set to a temperature lower than the glass transition temperature Tg by 100°C, the rest are all in accordance with Example 1- 1 Obtain glass samples in the same way. Various evaluations were performed in the same manner as in Example 1-1. A glass sample having the glass composition IV shown in Table 1(3) was produced. In the manufacture of the glass sample, except that the raw materials were prepared so as to become the glass composition IV, and the holding temperature Tx of step 2 was set to the same temperature as the glass transition temperature Tg, the rest were obtained in the same manner as in Example 1-1 Glass samples. Various evaluations were performed in the same manner as in Example 1-1.

(Example 4-2) A glass sample having the glass composition IV shown in Table 1(3) was produced. In the manufacture of the glass sample, the glass sample was obtained in the same manner as in Example 1-1 except that the raw materials were prepared so as to become the glass composition IV. Various evaluations were performed in the same manner as in Example 1-1.

[Table 1(1)] Composition (mass%) I II P ₂ O ₅ 1.10 0.76 SiO ₂ 23.27 31.91 Li ₂ O 5.66 5.26 Na ₂ O 5.15 11.06 K ₂ O 3.79 0.71 ZrO ₂ 5.82 8.75 Nb ₂ O ₅ 50.14 35.79 TiO ₂ 5.07 5.77 total 100 100 Sb ₂ O ₃ 0.02 0.02 {5×[TiO ₂ ]}/{3×[Nb ₂ O ₅ ]} 0.169 0.269

[Table 1(2)] Composition (mass%) III SiO ₂ 7.20 B ₂ O ₃ 12.40 SrO 0.29 BaO 31.94 La ₂ O ₃ 22.01 Y ₂ O ₃ 17.99 ZrO ₂ 2.35 TiO ₂ 5.82 total 100.00 {5×[TiO ₂ ]}/{3×[Nb ₂ O ₅ ]} -

[Table 1(3)] Composition (mass%) Ⅳ SiO ₂ 19.94 B ₂ O ₃ 3.11 Li ₂ O 1.76 CaO 14.78 SrO 1.69 BaO 3.36 La ₂ O ₃ 11.99 ZrO ₂ 2.34 Nb ₂ O ₅ 26.58 TiO ₂ 14.45 total 100 Sb ₂ O ₃ 0.050 {5×[TiO ₂ ]}/{3×[Nb ₂ O ₅ ]} 0.91

[Table 2(1)] Glass composition SiO ₂ (mass %) ZrO ₂ (mass%) nd νd Pg_F ⊿Pg_F -0.00286×νd+0.68700 proportion α _L (10 ^-5 ℃ ^-1 ) λτ80 (nm) λ70 (nm) Glass transition temperature Tg(℃) Step 2 holding temperature Tx (℃) Hold time of step 2 t ₁ (hr) Difference between Tx and Tg (℃) Comparative example 1-1 I 23.27 5.82 1.85455 25.18 0.610 0.007 0.615 3.486 0.81 389 395 553 580 0.5 +30 Comparative example 1-2 I 23.27 5.82 1.85403 25.18 0.610 0.007 0.615 3.487 0.81 389 395 553 550 0.5 0 Comparative example 1-3 I 23.27 5.82 Unable to determine Unable to determine Unable to determine Unable to determine Unable to determine 3.488 0.81 389 395 553 525 72 -25 Example 1-1 I 23.27 5.82 1.85355 25.19 0.610 0.007 0.615 3.486 0.81 389 395 553 525 0.5 -25 Example 1-2 I 23.27 5.82 1.85217 25.25 0.610 0.007 0.615 3.483 0.81 389 395 553 500 0.5 -50 Example 1-3 I 23.27 5.82 1.85116 25.26 0.610 0.007 0.615 3.480 0.81 389 395 553 450 0.5 -100 Comparative example 2-1 II 31.91 8.75 1.77090 29.26 0.598 0.002 0.603 3.267 0.82 369 372 562 560 0.5 0 Example 2-1 II 31.91 8.75 1.76788 29.34 0.598 0.002 0.603 3.264 0.82 369 372 562 500 0.5 -60 Example 3-1 III 7.20 2.35 1.80515 40.58 0.572 -0.003 0.571 4.607 0.90 688 630 0.5 -60 Example 3-2 III 7.20 2.35 0.572 -0.003 4.608 0.90 688 590 0.5 -100 Example 4-1 Ⅳ 19.99 2.35 1.9003 27.1 0.607 0.007 0.609 3.833 －－－ 429 445 640 640 0.5 0 Example 4-2 Ⅳ 19.99 2.35 1.90025 27.14 0.607 0.007 0.609 3.834 －－－ 428 445 640 615 0.5 -25

[Table 2(2)] Stability test crystal quantity density D (pieces/g) Maximum linear expansion coefficient α _max (10 ^-7 ℃ ^-1 ) (Bottom line is α _max (Tg)) Average linear expansion coefficient α _100-300 (10 ^-7 ℃ ^-1 ) α _max ×[SiO ₂ +ZrO ₂ ] α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ] α _max (Tg)-α _max (10 ^-7 ℃ ^-1 ) Comparative example 1-1 5.5×10 ⁴ 974 106 28333 266 -10 Comparative example 1-2 10 964 105 28043 268 0 Comparative example 1-3 9.5×10 ⁵ 1077 106 31335 295 -113 Example 1-1 2 925 106 26906 253 39 Example 1-2 - 720 107 20945 196 244 Example 1-3 0 631 106 18346 172 333 Comparative example 2-1 2.5×10 ³ 880 111 35764 321 0 Example 2-1 0 615 111 25006 224 265 Example 3-1 0 495 103 4728 46 67 Example 3-2 0 471 103 4499 44 91 Example 4-1 6 848 91 18942 208 0 Example 4-2 0 837 91 18696 205 11

(Example 3) Using the glass samples produced in Examples 1-1, 1-2, 1-3, 2-1, 3-1, 3-2, 4-1, 4-2, the lens blanks were produced by a known method, and then The lens blank is processed by a well-known method such as polishing to produce various lenses. The optical lenses produced include various lenses such as biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, concave meniscus lenses, and convex meniscus lenses. Various lenses are combined with lenses composed of other types of optical glass to well correct secondary chromatic aberration.

In the same way, various optical glasses produced in Examples 1-1, 1-2, 1-3, 2-1, 3-1, 3-2, 4-1, and 4-2 were used to make 稜頡.

The embodiments disclosed this time are all just examples, and should not be considered as limiting. The scope of the present invention is not limited to the above description, but is shown in accordance with the scope of the patent application, and all changes within the scope and meaning equivalent to the scope of the patent application are covered.

For example, with respect to the glass composition exemplified above, the optical glass of one aspect of the present invention can be produced by adjusting the composition described in the specification. In addition, of course, two or more items described in the specification or described in the preferred range may be combined arbitrarily.

without.

[Fig. 1] Fig. 1 is an example of the glass material for molding of the present embodiment, and a glass temperature chart during the manufacturing step; the vertical axis is the glass temperature, and the horizontal axis is the time (seconds) expressed in logarithm.

Claims (8)

A glass material for molding, which is the maximum linear expansion coefficient α _max , and the total content _{of SiO 2} and ZrO ₂ expressed by mass% _{[SiO 2} +ZrO ₂ ], which satisfies the following formula (1): α _max ×[SiO ₂ + ZrO ₂ ]≦27900 ・・・(1). A glass material for molding, which has the maximum linear expansion coefficient α _max , the average linear expansion coefficient α _{100-300 at 100-300} ℃, and the total content _{of SiO 2} and ZrO ₂ expressed by mass% _{[SiO 2} +ZrO ₂ ], which satisfies The following formula (4): α _max /α _100-300 ×[SiO ₂ +ZrO ₂ ]≦264 ・・・(4). A glass material for molding, the maximum linear expansion coefficient α _{max is} smaller than that after the glass material for molding is soaked according to the glass transition temperature Tg, then cooled at -30°C/hr for 4 hours, and then placed in a cold room. Obtain the maximum linear expansion coefficient α _max (Tg) of the glass material. The glass material for molding as described in any one of claims 1 to 3, in which, when a sample of 11mm×11mm×10.5mm is heat-treated for 5 minutes at a temperature 200°C higher than the glass transition temperature Tg, the glass will crystallize per 1g The number density D is less than 10 pieces/g. The molding glass material of any one of claims 1 to 4, requested items, wherein, TiO ₂ content by mass% of [TiO _2] and Nb ₂ O ₅ content [Nb ₂ O _5], based satisfies the following formula (7 ): {5×[TiO ₂ ]}/{3×[Nb ₂ O ₅ ]}≦3 ・・・(7). _{The glass material for molding as described in any one of claims 1 to 5, wherein the wavelength λτ 80} at which the internal transmittance of glass with a thickness of 10 mm is 80% in the wavelength range of 280 to 700 nm is below 395 nm. The molding glass material described in any one of claims 1 to 6, wherein the Abbe number νd and the partial dispersion ratio Pg, F satisfy the following formula (8): Pg,F≦-0.00286×νd+0.68700 ・・・(8). An optical glass formed from the glass material for molding described in any one of Claims 1 to 7.

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