WO2002014235A1 - Low fluorescent optical glass - Google Patents

Abstract

A low fluorescent optical glass which comprises, in mass % on oxide basis, 30 to 45 % of SiO2, 0.5 to 10 % of ZrO2, 30 to 50 % of Nb2O5, 0 to 15 % of Ta2O5, 0 % or more and less than 12 % of Li2O, 0 % or more and less than 12 % of Na2O, 0 % or more and less than 12 % of K2O, provided that the sum of Li2O, Na2O and Na2O is 1 to 12 %. The low fluorescent optical glass has high refractive index and high dispersion i.e. a refractive index of 1.68 to 1.78 and an Abbe's number of 27 to 35, is reduced in the intensity of fluorescence emitted by the excitation with ultraviolet rays, has excellent chemical durability and excellent light transmittance and further can be produced at a relatively low material cost.

Description

 Technical field of low-fluorescence optical glass — The present invention has a refractive index (nd) of 1.68 to 1.78, an Abbe number (vd) of 27 to 35, and a fluorescence intensity (ultraviolet ray) excited by ultraviolet light. Low fluorescence optical glass with low luminous intensity. Field background technology

 In the fields of biology and medicine, there are many techniques for irradiating excitation light such as ultraviolet rays to an observation target and observing and measuring the fluorescence emitted from the observation target in order to observe biological tissues, cells, and bacteria. In recent years, techniques for detecting weak fluorescence emitted from a very small amount of bacteria, cells, and the like have been actively studied. However, fluorescent light is also generated from the optical glass used for the objective lens of the fluorescence microscope used for such observation and measurement by excitation with ultraviolet light, and this fluorescent light ′ is observed when observing the fluorescent light emitted from the observation target. Because of the noise, there is a demand for an optical glass that has a low intensity of fluorescence generated by ultraviolet excitation (indicated by the Japanese Optical Glass Industrial Association standard as the fluorescence intensity).

The optical system such as the objective lens of a fluorescence microscope, which is highly aberration-corrected, is composed of optical glass with various refractive indices and dispersions. Conventional optical glass, especially high-dispersion optical glass, has ultraviolet excitation. There is hardly any consideration to reduce the fluorescence (fluorescence) due to light. As mentioned above, due to the problem of noise, the conventional high-dispersion optical glass with high fluorescence and the excitation light in the ultraviolet region are used. It cannot be used in the optical system of a fluorescence microscope optical device that irradiates the observation target and observes or measures the weak fluorescence generated from the observation target. For the above reasons, several high-dispersion low-fluorescence optical glasses have been proposed in recent years. For example, Japanese Patent Laid-Open No. 10- 158029, B ₂ 〇 ₃ _P ₂ 0 ₅ - R 〇 one N b ₂ 〇 ₅ and Z or T a ₂ 〇 ₅ based high dispersion low fluorescence optical glass composition is disclosed However, this glass has the disadvantage that its chemical IS durability is not sufficient. Also, Japanese Patent Application Laid-Open No. Hei 10-231140 discloses a high-dispersion, low-fluorescence optical glass having a composition of B ₂ — ₃ —P ₂ 〇 ₅ —R Ta Ta ₂ 〇 ₅ system. Las immediately, is not sufficient chemical durability and light transmittance, because the raw material cost is introduced a large number of very high cost of Ta ₂ 〇 ₅ components, also has a problem that the production cost Bok high .

Japanese Patent Application Laid-Open No. 10-316449 discloses a high-dispersion, low-fluorescence optical glass having a Ge ₂ — ₃ —Ta ₂ 〇 ₅ —RO system composition, but this glass also has insufficient chemical durability. no, in addition to containing a large amount of Ta ₂ 〇 ₅ components, ya Ri, since the raw material costs are contained in a large amount is also very expensive Ge ₂ 〇 _three components, manufacturing costs I very High and not practical.

Of course, optical glass is required to have excellent light transmittance.However, in the process of grinding or polishing the optical glass and the process of cleaning lenses, etc., the surface of the glass is damaged. In order to prevent the occurrence of glass, the glass must have excellent chemical durability. In addition, in order to reduce the manufacturing cost, it is desirable that the raw material costs of the components constituting the optical glass be as low as possible. However, as described above, the conventional high-dispersion, low-fluorescence optical glass cannot be said to sufficiently meet these requirements. An object of the present invention is to solve the above-mentioned problems of the prior art comprehensively and to obtain a high refractive index (nd) power of 1.68 to 1.78 and an Abbe number (le d) of 27 to 35. Provide low-fluorescence optical glass that has dispersibility, has low fluorescence intensity when excited by ultraviolet light, has excellent chemical durability and light transmittance, and can be manufactured at a relatively low material cost. Is to do. Disclosure of the invention

As a result of extensive studies, the present inventor has found that S i 0 ₂ -Z r 0 ₂ -Nb ₂ O _s -R ₂ 0 (R is Li, One or two or more selected from Na and K) ¾ glass, having the above-mentioned optical constants (refractive index (nd) and Abbe number (li d)), low fluorescence intensity by ultraviolet excitation, and The present inventors have found that a glass having excellent chemical durability and light transmittance can be obtained, and have accomplished the present invention.

 That is, the low-fluorescence optical glass of the first embodiment according to the present invention has an oxide-based mass%

S i O, 30-45%,

_{Z r 0 2 0. 5~: L} 0%,

Nb ₂ O _s 30~ 50%,

Ta ₂ 〇 ₅ 0-15 percent,

L i _200- less than 12%,

Na, O 0 to less than 12%,

K _200- less than 12%,

However, L i ₂ O + N a ₂ 〇 + K ₂ 〇 12% i full,

 Mg〇 0-4%,

 C aO 0-4%,

 S r〇 0-4%,

 B a〇 0-4%,

 Zn〇 0-4%, '

Where Mg〇 + C a〇 + S r〇 + B a〇 + Z ηθ 0 ~ 4%.

Sb ₂ 〇 ₃ 0-1%,

A s _z 0 ₃ 0-1%

Wherein each component is contained. The low-fluorescence optical glass of the second aspect according to the present invention has an oxide-based mass%

S i〇 ₂ 30-45%,

Z r〇 ₂ 0.5 ~: L 0%,

Nb ₂ 0 ₅ 30-50%,-

_{T a 2 0 5 0~ 15%} ,

However, Nb ₂ 〇 ₅ + Ta ₂ 〇 ₅ is 55% or less,

L i ₂ O 0 to less than 12%,

N a ₂ O 0 to less than 12%,

K ₂ 〇 0-: I less than 2%,

However, Li ₂ 0 + Na ₂ 〇 + K ₂ 0 7 to less than 12%,

And, by mass ratio, S i〇 ₂ / (L i ₂ 〇 + Na ₂ 〇 + K ₂ 〇) is 3.3 or more,

S 0 ₃ 0-1%,

A s ₂ 〇 ₃₀ 0 to 1%

Wherein each component is contained.

Preferably, in low fluorescence optical glass of the first and second aspects of the present invention, in mass percent on the oxide basis, Ta ₂ 〇 ₅ content from 0.5 to 1 less than 1% of It is.

 Preferably, the low-fluorescence optical glass according to the first and second embodiments of the present invention has a refractive index (nd) of 1.68 to 1.78 and an Abbe number (d) of 27 to 35. Has an optical constant in the range of

Preferably, in the low-fluorescence optical glass according to the first and second aspects of the present invention, the acid resistance (SR) of the glass measured by the measuring method of International Standards Organization IS 08424: 1996 (E). The grade is grade 1. BEST MODE FOR CARRYING OUT THE INVENTION The reason why the composition range of each component is limited as described above in the low-fluorescence optical glass of the present invention will be described below.

That, S i 0 ₂ component, as well as a glass forming oxide is a component for improving the stability and chemical durability of the glass against devitrification, to maintain the stability and chemical durability against devitrification Requires more than 30%. On the other hand, if the amount exceeds 45%, the glass is rather devitrified, and the obtained glass tends to be milky white.

Z r0 ₂ component to increase the refractive index of the glass, the chemical durability is improved, and is a component effective for suppressing the devitrification tendency of the glass, its amount is 0.5 less than 5% In this case, the above effect is not sufficient, and if it exceeds 10%, the glass tends to be more devitrified.

Nb ₂ 0 ₅ component in the present invention, while maintaining the optical constants of the desired range, is an important component is effective to significantly reduce the fluorescence by ultraviolet ray excitation, with its amount is less than 20% the No effect is obtained, and if it exceeds 50%, light transmittance deteriorates. .

Further, Nb ₂ 〇 ₅ component is not as much as T a ₂ 〇 _five components to be described later, a relatively high component material costs, the case of adding T a ₂ 〇 ₅ components, reduction in the manufacturing cost of the glass for, Nb ₂ 〇 ₅ and T a ₂ 〇 ₅ the total amount of components 55% or less and to Rukoto force, more preferably.

Ta ₂ 〇 ₅ component, by incorporating the glass, while maintaining the optical constants of the desired range, mosquitoes which may be added to any because of the effect of improving the light transmittance and chemical durability, the amount is 1 If more than 5%, and deteriorated significantly meltability, T a ₂ 〇 ₅ undissolved prone components.

In order to sufficiently exhibit the above effect, it is more preferable that the content of Ding & ₂ 〇 _five components 0.5% or more. Further, Ta ₂ 0 ₅ component, among the components of the glass of the present invention, in particular, raw material cost is high component, while obtaining the above effects, glass In order to keep the production cost of the glass low and to further improve the melting property of the glass to make it easier to obtain a homogeneous glass, the amount is more preferably less than 11%.

Each of the components L i ₂ 〇, Na ₂ 〇 and K ₂が あ る has the effect of accelerating the melting of glass, but the total amount of one or more of these components is less than 1% If the above effects are not sufficiently obtained, and if the total amount exceeds 12%, it becomes difficult to obtain the desired high refractive index and high dispersion, and the fluorescence intensity tends to increase.

In order to particularly improve the melting property of the glass, it is more preferable that the total amount of one or more of these components is 7% or more. In addition, when melting or refining glass using a platinum or platinum alloy crucible or a refining tank, the melting point of platinum ions is reduced while the melting promotion effect is obtained, and the light transmittance is particularly excellent. In order to obtain glass, it is more preferable that S i 0 / (L i ₂₀ + Na ₂ 〇 + K ₂₀ ) be 3.3 or more in terms of mass ratio.

 All of the BaO, Ca Mg, MgO, Sr〇 and Zn〇 components can be added as needed for the purpose of adjusting the optical constants and improving the melting property and devitrification resistance of the glass. However, when the total amount of one or more of these five components exceeds 4%, the light transmittance is significantly deteriorated.

S b ₂ 0 ₃ and A s ₂ 〇 _three components, respectively, but it may be optionally added as a refining agent in the glass melting, in order to obtain the effect of fining is sufficient up to 1%, especially In order to obtain a glass having excellent light transmittance and low fluorescence, the amounts of these components are more preferably set to 0.5% or less, respectively. % Is more preferable, and even if the amount of each of these components is 0.3% or less, fining can be sufficiently performed by adjusting the dissolution conditions. In addition, a component other than the above, for example, a B ₂成分₃ component may be added to the glass of the present invention as needed up to 5% for the purpose of adjusting the optical constant and improving the melting property. In addition, the content of F (fluorine) is reduced to 4% to improve the light transmittance. For the purpose of improving the melting property and the devitrification resistance of the glass, it may be added to the glass of the present invention as needed. Example '

The compositions of the preferred examples (No. l to No. 14) of the low-fluorescence optical glass of the present invention and the compositions of comparative examples (No. A and No. B) of the conventional optical glass are shown below. Measurement of refractive index (nd), Abbe number (d), spectral wavelength including reflection loss, wavelength of light showing 80% transmittance (T8 ₍₎ ; unit: nm), fluorescence (fluorescence) and acid resistance The results are shown in Tables 1 to 3 together with the class (SR). Where T _s . The figure shows the measurement results for a 10 mm thick glass sample polished face-to-face. In addition, measurement of silicon luminosity, carried out on the basis of the Japan Optical Glass Industry Association standard "method of measuring only have luminous intensity of optical glass" (J_〇_GISO ^3-1975), as a standard sample, of Japan Optical Glass Industry Association specified Using flint glass, the intensity of fluorescence (fluorescence) generated by irradiating the glass samples of the examples and comparative examples and the above standard sample with ultraviolet light having a main wavelength of 365 nm was measured. The fluorescence intensity is calculated from the measured fluorescence intensity, and the ratio of the fluorescence intensity of each glass sample to the standard sample is calculated. If it is less than 5, it is shown as Class 2, and if it is less than 0.7, it is shown as Class 1. If the glass has a fluorescence intensity of class 1, the intensity of the fluorescence by ultraviolet excitation is sufficiently small, and it can be used for an objective lens of a fluorescence microscope.

The class showing acid resistance (SR) shows the results obtained by measurement according to the measurement method of International Organization for Standardization I S08424: 1996 (E). Here, the SR was graded according to the time (h) required for a glass sample of 30 x 30 x 2 mm, whose six surfaces were polished, to undergo 0.1 m erosion in a given acid treatment solution. And if 3 is 1, 2, 3 and 4, use a nitric acid solution of pHO.3 to erode more than 100 respectively !!, 100 h to 10 h, 10 h Less than lh and less than Ih to 0.1h. Therefore, the smaller the SR class value, the higher the acid resistance of the glass and the better the chemical durability.

 The acid resistance class (SR) shown in Table 4 is obtained by further subdividing the acid resistance class (SR) shown in Tables 1 to 3 by the measurement method of IS 08424: 1996 (E) above. The surface of the glass sample immediately after the acid treatment was observed, and the change in the polished surface caused by the acid treatment was classified as follows. For example, when SR was grade 1.0, erosion was 100%. This indicates that the required h is exceeded and that the polished surface does not change immediately after the acid treatment.

 . 0 No change

 . 1 clean, but irregular surface (undulations, dents)

 .2 interference color (slight selective elution)

 . 3 Sticky white layer (stronger selective elution)

. 4 Debris that easily breaks down (surface crust)

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鰂 ¾%

/ OSAV:

鰂 >>

/ OSAV:

鰂 ¾

Four

 Example Comparative example

No. 7 9 13 B

SR (grade) 1.0 1.0 1.0 2.4

As can be seen from Tables 1 to 3, the glasses (No. 1 to No. 14) of the examples of the present invention all have a refractive index (nd) force of 1.68 to 1.78 and an Abbe number (レ cl ) Has an optical constant in the range of 27-35. In addition, the glasses (No. 1 to No. 14) of the examples of the present invention all have the conventional high dispersibility of Comparative Example No. A in which the luminosity is class 1 and the luminosity is class 2. It can be seen that the fluorescence intensity by ultraviolet excitation is smaller than that of optical glass.

 In addition, all of the glasses (No. l to No. 14) of the examples of the present invention have a conventional high dispersion of Comparative Example No. B in which the acid resistance (SR) is class 1 and the SR is class 2. It shows that it has better acid resistance and better chemical durability than low fluorescent optical glass.

 Further, as can be seen from Table 4, the glasses of Examples of the present invention (No. 7, No. 9 and No. 13) have a classified acid resistance (SR) of 1.0, It can be seen that the acid resistance is remarkably superior to the conventional high-dispersion low-fluorescence optical glass of Comparative Example No. B, whose SR) grade is 2.4.

Further, the glass (No. 1 to No. 14) of the example of the present invention has a wavelength (T _{8 ()} ) of light having a spectral transmittance of 80% including reflection loss within a range of 365 to 397 nm. _Yes , compared to the conventional optical glass of Comparative Examples No. A and No. B, the wavelength ( _{光線 8ϋ} ) of the light beam that shows a spectral transmittance of 80% including the reflection loss is almost equal or shorter. It can be seen that the light transmittance is excellent in the near ultraviolet region from the short wavelength side of the visible region.

Incidentally, the glasses (No. 1 to No. 14) of the examples of the present invention whose compositions are shown in Tables 1 to 3 are all ordinary optical glass such as oxides, carbonates, nitrates and hydroxides. The raw materials are mixed and weighed to a specified ratio, then put into a platinum crucible, etc., and melted at a temperature of 1100-1350 ° C for about 2-4 hours, depending on the melting property of the composition, and stirred. After homogenization, it was easily obtained by inserting into a mold and slowly cooling. Industrial applicability

As described above, low fluorescence optical glass of the present _{invention, S i 0 2 -Z r 0} 2 -Nb 2 0 5 -R 2 0 (R a specific composition range, selected from L i, N a and K (1 or 2 or more types) glass, and has a refractive index (nd) power of 0.68 to; L. 78, an Abbe number (vd) of 27 to 35, and a high optical constant. It has a refractive index and high dispersion, has low fluorescence when excited by ultraviolet light, has low fluorescence, and has excellent chemical durability and light transmittance. Therefore, it is particularly suitable for use as an objective lens of an optical system such as a fluorescence microscope, and is used as a glass member requiring low fluorescence such as a solution cell for fluorescence measurement or a cover glass of a solid-state imaging device. Also suitable for. It is also suitable and useful as ordinary optical glass for use as lenses in optical systems of various optical devices such as cameras, digital cameras, and video cameras. Also, since the raw material cost does not contain a large amount of expensive components, it is more advantageous than conventional high-dispersion low-fluorescence optical glass in terms of manufacturing cost.

Claims

In mass% based on oxide, S 10 ₂ 30-45%, Z r0 ₂ 0.5 to 10%, Nb ₂ 0 ₅ 30-50%, T a, O _t 0-15%, L i ₂ O 0 to less than 12%, of N a ₂ O 0 to less than 12%, K „〇 0 to less than 12%, However, L i, 0 + Na, 〇 + K, 〇 less than 2%,  MgO 0-4%, C a O 0-4%, SrO 0-4%, B aO 0-4%, ZnO 0-4%, However, Mg〇 + Ca〇 + S r〇 + B a〇 + Zn〇 0 ~ 4%, S b ₂ 〇 ₃₀ 0 ~ 1%, -A s ₂ 0 ₃ 0 ~ 1% Low fluorescence optical glass characterized by containing each component in the range of < 2. In mass% based on oxide, S i〇. '30-45%,  ZrO, 0.5-10%, Nb, O _t 30~50%, Ta ₂ 0 ₅ 0~15%, However, Nb ₂ 〇 ₅ + T a ₂ 〇 ₅ is 55% or less, Mg〇 0-4%,.  C a〇 0-4%, SrO 0-4%, B aO 0-4%, Z nO 0-4%, Where MgO + C a〇 + S r〇 + B a〇 + Z nO 0-4%, L i ₂ O 0 to less than 12%, N a ₂ 〇 0-: less than 12%, K ₂ O 0 to less than 12%, However, Li ₂ 0 + Na ₂ 〇 + K ₂ 0 7 to less than 12%, And, by mass ratio, S i〇no (L i ₂ 〇 + Na ₂₀ + K ₂ 〇) is 3.3 or more, S b ₂ 0 ₃ 0-1%, A s ₂ 0 ₃ 0 to 1% A low-fluorescent optical glass comprising the components described in (1). 3. in terms of% by mass on the oxide basis, low fluorescence optical glass according to claim 1 or 2, characterized in that the Ta less than ₂ 〇 ₅ 0.5 to 1 1%.  4. The method according to claim 1, wherein the refractive index (nd) has an optical constant in the range of 1.68 to 1.78, and the Abbe number (d) in the range of 27 to 35. Low fluorescent optical glass. . 5. The glass according to the International Standards Organization IS 08424: 1996 (E), wherein the glass has an acidity (SR) class of class 1. 5. The low-fluorescence optical glass according to 3, 3 or 4.