KR20130018177A - Fluorophosphate glass and method for producing the same and near-infrared absorbing filter - Google Patents

Abstract

PURPOSE: A fluoride phosphate glass is provided to suppress an excessive absorption of visible light as absorbing near infrared light by controlling mole ratio(F-/(O2- + F-)) of F-content compared to the content summation of O2- and F-, and mole ratio(O2-/P5+) of O2- content compared to the content of P5+. CONSTITUTION: A fluoride phosphate glass absorbs a near infrared light by containing Cu2+. From the fluoride phosphate glass, the mole ratio(O2-/P5+) of O2- content compared to P5+ content is over 3.2 and less than 3.4. From the fluoride phosphate glass, the mole ratio(F-/(O2- + F-)) of F- content compared to O2- and F- content summation is over 0.05 and less than 0.25. The fluoride phosphate glass may not comprise B3+, Pb, the ion and compound, TI, the ion and compound. From the fluoride phosphate glass, the ratio of rare-earth ion content to content of all cation elements is over 0.5 cation% and less than 2.0 cation%. The near infrared light absorbing filter uses the fluoride phosphate glass. [Reference numerals] (AA,HH) Optical density; (BB,II) Wavenumber; (CC,JJ) Experimental spectrum; (DD,KK) Loss due to surface reflection; (EE,LL) Visible light peak(large); (FF,MM) Infrared light peak(small); (GG,NN) Composite spectrum

Description

Fluorinated phosphate glass and its manufacturing method and near-infrared light absorption filter {FLUOROPHOSPHATE GLASS AND METHOD FOR PRODUCING THE SAME AND NEAR-INFRARED ABSORBING FILTER}

TECHNICAL FIELD The present invention relates to fluorinated phosphate glass, a method for producing the same, and a near infrared ray absorption filter, and more particularly, to a fluorinated phosphate glass, a method for producing the same and a near infrared ray absorption filter.

Fluorinated phosphate glass is very useful as a low dispersion glass although it is a glass which has weather resistance, As such glass, the glass as described in patent documents 1-6 is known.

By the way, when combining a glass raw material based on the composition from which a required optical characteristic is obtained, and heating and melting, and producing fluorophosphate glass, there exist a following subject normally.

Fluorinated phosphate glass generally shows remarkable volatility at the time of manufacture. As a bad effect which volatilization of a molten glass brings about, the problem that a stria generate | occur | produces in the surface vicinity and inside of glass, and since a glass composition changes with progress of volatilization, there exists a subject that a characteristic of glass changes with time.

In addition, volatilization occurs by the production of phosphoryl fluoride (POF ₃ ) in the manufacturing process. Further, as the volatile fluorinated phosphoryl is hydrolyzed, hydrogen fluoride (HF) is also generated, so that white lead containing them is generated. Since these compounds may damage the glass manufacturing equipment, it is necessary to take measures beyond the usual one. As a result, enormous costs are incurred to cope with volatilization by-products, and the burden on workers increases.

MEANS TO SOLVE THE PROBLEM This inventor discloses the result which considered the cause of the said volatility in patent documents 7-10 in order to improve such a situation. The outline of the content is as follows.

When producing fluorinated phosphate glass, a phosphate raw material is generally used, but in order to increase the amount of fluorine ions introduced as an anion component, the ratio of the number of oxygen atoms (oxygen atom / phosphorus atom) to one phosphorus atom as the phosphate is Small metaphosphates (oxygen atom (O) / phosphorus atom (P) = 3, ie PO ₃ ) are used. For this reason, the ratio of the quantity of the oxygen atom to the quantity of the phosphorus atom is often 3 in the general purpose glass of the fluorinated phosphate system until now.

However, as a result of the present inventor's investigation, when using only metaphosphate as an oxide raw material and making glass with an oxygen / phosphorus ratio of 3, the metaphosphoric acid and fluorine which originate in a raw material react in molten glass, and phosphoryl fluoride which shows remarkable volatility is made. (POF ₃ ) was found to occur. On the other hand, when an oxide raw material other than metaphosphate is added or the pyrophosphate raw material is used to adjust the atomic ratio of oxygen atoms per phosphorus atom in the molten glass to 3.5 or more (oxygen atom / phosphorus atom≥3.5), It was found that the generation amount was greatly reduced. This melt as phosphate existing in the glass, the number of oxygen atom ratio of the first atom (oxygen atoms / phosphorus atoms) is 3 or more than metaphosphoric acid, an oxygen atom / phosphorus atom is 3.5-diphosphate (pyrophosphate, i.e., P ₂ O ₇ ) is considered to be stable.

Based on the above knowledge, in order to suppress the volatilization, the present inventors have a molar ratio (O ^2- / P ⁵⁺ ) of O ^{2 -} to the P ^{5 +} content in the fluorinated phosphate glass, or the phosphorus atoms contained in the raw materials. Attention is paid to the molar ratio (O / P) of the content of the oxygen atom to the content, and the method of making these values 3.5 or more is disclosed, and the methods are disclosed in Patent Documents 7 to 10.

In addition, the present applicant also discloses the method of setting it to 3.5 or more similarly in patent document 11.

In addition, the present inventors, in the Patent Document 12, O ² to P ^{5 +} content in hexafluorophosphate glass ^- the molar ratio of the content (O ^2- / P ⁵⁺⁾ to more than 3.4 and, in the O hexafluorophosphate glass F for the total amount ^{- - 2-F,} and the molar ratio of the content, discloses a method to more than 0.05.

Since, for the sake of convenience, the at hexafluorophosphate glass (hereinafter described as P ^{5 +)} oxygen to the content of the description ^- the (O ² referred to as base material), molar ratio of the content ^- and as "O ² / P ^{5 +} ratio" material The molar ratio (O / P) of the oxygen (described as O) content to the phosphorus (described as P) content contained therein is also referred to as "raw material O / P ratio".

Japanese Patent Laid-Open No. 10-139454 Japanese Patent Laid-Open No. 6-16451 Japanese Patent Laid-Open No. 8-253341 Japanese Patent Laid-Open No. 3-232735 Japanese Patent Laid-Open No. Hei 1-219073 Japanese Patent Laid-Open No. 3-83834 Japanese Patent Publication No. 2010-59019 Japanese Patent Publication No. 2010-59021 Japanese Patent Laid-Open No. 2010-59022 Japanese Patent Laid-Open No. 2010-59023 Japanese Patent Laid-Open No. 2011-132077 Japanese Patent Laid-Open No. 2011-93757

Before explaining the problem to be solved by the present invention, the reason for setting the O ^{2 −} / P ^{5 +} ratio to 3.5 or more in Patent Documents 7 to 10 is described in detail in terms of mechanism.

Patent Document until the 7 and 10 is started, as described above, in the general-purpose glass-based hexafluorophosphate, O ^{2 -} / P ^{5 +} It was typical ratio is 3. O ^{2 -} / P ^{5 +} when the ratio of 3 days, by the O and P bond in the glass, and form the long POP chain. The POP chains are oriented in a plurality and entangled with each other, so that the fluorinated phosphate-based glass is qualified as a glass used for practical use.

By the way, if fluorine (F) is present when the O ^{2 −} / P ^{5 +} ratio is 3, there is a possibility that the bond between O and P in the POP chain is cleaved by F. As a result, the above volatile matter (POF ₃ or HF) may occur as a by-product. In order to prevent this, in Patent Documents 7 to 10, before the POP chain is cut by F by increasing the O ^{2 −} / P ^{5 +} ratio (that is, containing a large amount of oxygen (O)) than usual, and a POP chain is cut in advance by the use of O metaphosphate structure (i.e. PO ₃₎ from the blood placed by changing a phosphate structure (i.e. P ₂ O ₇₎ are mechanisms.

On the other hand, O ^{2 -} / P by increasing the ^{5 +} ratio, in the C-based glass containing Cu ^{2 +,} near infrared light is task is absorbed, however, the absorption of visible light is too strong, resulting lowering the practicability as an optical filter is also , By the inventors. More specifically the time of forming the plate-like hexafluorophosphate glass having a predetermined thickness, when added to Cu ^{2 +} in the material to near-infrared light so absorbent, O ^{2 -} / P ^{5 +} high ratio, O ^{2 -} / P ^{5 +} ratio point 're excessively absorb visible light than when 3, that is, if I use up to the amount of Cu ^{2 +} enough to absorb near infrared light as a raw material, followed by apparent from the present inventors point' re excessively absorb visible light Done

In addition, specifically described later hageteuna, excessive absorption of the visible light, the O ^{2 -} point / P ⁵⁺ to give rain effect, and in view of this effect, O ² is set up to solve the above problems ^- / P ratio ^{+ 5} The inventors have obtained the knowledge that the amount of fluorine (F) in the glass must be considered in order to have the fluorinated phosphate glass after production.

An object of the present invention, absorption of but absorbs the near infrared light visible light is O ² is set to be added to the amount of Cu ^{2 +} of the degree of suppressing ^- having a / P, weather resistance having ^{5 +} ratio after manufacturing hexafluorophosphate glass And a method for producing the same and a near-infrared light absorption filter.

MEANS TO SOLVE THE PROBLEM This inventor decided to follow the policy of the technology of patent documents 7-10 by this inventor as a basic policy first. In other words, the O ^{2 −} / P ^{5 +} ratio was made higher than that in the prior art (3.0), and at first, the policy of suppressing volatilization of by-products was adopted. In this way, by cutting, POP chain by O in advance as described above, it is possible to suppress the occurrence of POF _3. Moreover, since POP chain may be cut | disconnected by the water molecule contained in the atmosphere at the time of manufacturing fluorophosphate glass, it is estimated that weather resistance can also be improved by cutting POP chain to some extent beforehand. .

On the other hand, O ^{2 -} / P ⁵⁺ If the ratio higher than the prior art, O ² at hexafluorophosphate glass ^- it is necessary to increase the content molar ratio of ^- F for the total content ^- and F. This is because by increasing the O ^{2 −} / P ^{5 +} ratio, since the POP chain is cut by O, the glass forming ability decreases and glass becomes prone to crystallization remarkably. Therefore, by raising the molar ratio of said F <^-> content in glass, the structure in which POP chain was cut | disconnected can be tied together through F between pyrophosphoric acid structures. By doing in this way, the fluorinated phosphate type glass can be used practically.

Since, for convenience, the oxygen in the hexafluorophosphate glass description (O ^{2 -} also indicated as) and a fluorine ^- the total content of (F hereinafter described as) (O ^{2 -} + F ^{-), -} the molar ratio of the content (F F for ^- / (O ^2- + F ^-)), the "F ^- ratio" referred to, hereinafter described as oxygen (O contained in the raw material) and fluorine (also indicated as F), the total F content of the content (O + F) The molar ratio of (F / (O + F)) is also called "raw material F ratio". However, although it mentions later in detail, in this invention, the method which substantially does not generate | occur | produce a volatile substance is employ | adopted. Therefore, said raw material F ratio becomes substantially the same as F <^-> in product glass.

Returning the story to the origin, by increasing the O ^{2 −} / P ^{5 +} ratio, POP chains in the glass often take a pyrophosphate structure (that is, P ₂ O ₇ ). As a result, other metals (Li and the like) in the glass and the pyrophosphoric acid structure may bind to each other to form crystals. When crystal | crystallization generate | occur | produces in glass, it will result in the remarkable fall of an optical characteristic. As a countermeasure, F is interposed between pyrophosphoric acid structures by increasing the F ^- ratio in the glass. By doing in this way, formation of the said crystal | crystallization can be suppressed.

Here, O ² of the embodiment in Patent Document 2 to 6 ^- / P ^{5 +} ratio while levels in excess of 3.0, and to select the 3.5 less, O ^{2 -} / P ^{5 +} ratio and F ^- with respect to non-schedule 1 is shown. As shown in FIG. 1, when the O ^{2 −} / P ^{5 +} ratio is set to have sufficient weather resistance, the F ⁻ ratio is usually at least 0.30 or more, as long as the aim is to have sufficient weather resistance. It was common sense.

In addition, Patent Document 12 describes that the O ^{2 −} / P ^{5 +} ratio is 3.4 or more and the F ⁻ ratio is 0.05 or more, but when λ 50 = 615 nm in the near infrared region (1200 nm). The decrease in the spectral transmittance (hereinafter, also simply referred to as "transmittance") remains at about 23% (see Example (Patent Table 1 below) in Patent Document 12). As a cause of this, even in the visible light region (615 nm), absorption of constant light is performed. → The glass thickness of λ 50 = 615 nm may be thin. → As the glass thickness becomes thin, the absorption of near infrared light cannot be sufficiently performed. It seems to have a causal relationship.

In view of the above situation, the present inventors have studied the above problems. As a result, the following three knowledges were obtained by broadly dividing the invention.

[Knowledge 1] absorption spectrum with respect to the acid fluoride glass containing Cu ^{+ 2:} and has a single peak when analyzed by a (horizontal axis represents wave number (K (Kaiser = ㎝ ^-1))), a near infrared wavelength to a visible light wavelength. However, this one peak can be separated into two peaks: an infrared light peak and a visible light peak. The intensity of the visible light peak is affected by the O ^{2 −} / P ^{5 +} ratio.

[Knowledge 2] Even if a predetermined amount of raw material is blended so that the final glass composition has a predetermined O ^{2 −} / P ^{5 +} ratio, if the raw material F ratio is high (or the melting temperature is high), at least in the raw material step, O ^{2 -} / P ⁵⁺ case of setting the ratio at about 3.0, the by-product, from the raw material stage up to the step after the production of glass, in fact, O ^2, by the ^volatile-and / P ⁵⁺ ratio changes. That is, the O ^{2 −} / P ^{5 +} ratio in the product glass is influenced by the raw material F ratio (or melting temperature).

[Knowledge 3] In the [Knowledge 2], the O ^{2 −} / P ^{5 +} ratio that varies from the raw material step to the post-glass production step is about 3.3. Value, known as the 3.3 shows an tripolyphosphate structure (i.e., P ₃ O _10).

Hereinafter, the process which arrived at this invention is demonstrated in order, explaining each knowledge in detail.

First, with respect to inde [knowledge 1], for the analysis of the absorption spectrum with respect to the acid fluoride glass containing Cu ^{+ 2,} it is shown in FIG. Then, the absorption peak in this Figure 2, the original Cu ^{2 +} the infrared light side peak (S) to be absorbed, and the infrared light side peak than the short-wavelength-side visible light which is located in (i.e., hungry water side) side of the peak (for Can be divided into The result is shown in FIG. In addition, the In (a) of FIG. 3, O ^{2 -} / P ⁵⁺ a ratio of 3.5 and, in the Figure ^{3 (b), O 2 -} / P ⁵⁺ is the ratio to 3.18.

3, the absorption peak (* attached solid line) in a measured spectrum is the infrared side peak (broken line) which Cu <^2+> wants to absorb originally, and the visible side peak which is located shorter wavelength side than the infrared side peak ( Solid line). In addition, when (a) of FIG. 3 is compared with (b) of FIG. 3, the intensity of the visible light peak is lower in the lower O ^{2 −} / P ^{5 +} ratio (that is, in FIG. 3 (b)). I can see that there is. In addition, there was almost no difference in both the width and intensity of the infrared side peak, and there was almost no difference in the width of the visible side peak. Also, there was almost no difference in both of the peak positions.

In addition, the spectral transmittance finally calculated | required contains the loss by surface reflection. In order to consider this loss, the loss (dotted line) by surface reflection is also considered in absorbance. However, in FIG. 3, since the change amount of the reflectance by the change of a refractive index is small generally, it calculates by making a reflectance constant regardless of a wavelength.

In addition, the spectrum measured with respect to the product glass (* attached solid line) is a spectrum which synthesize | combined the loss by surface reflection, superimposing the normal distribution spectrum which divided this into two (namely, an infrared side peak and a visible side peak) (long wave line). Is almost identical to).

Here, in consideration of the results of the glass of the higher O ^{2 −} / P ^{5 +} ratio (FIG. 3 (a)) and the glass of the lower of the O ^{2 −} / P ^{5 +} ratio (FIG. 3 (b)), Consider the case of producing a plate glass having a constant thickness and a constant near infrared light absorbing ability (specifically, a transmittance of 10% when the wavelength is 1200 nm (about 8300 K)). That is, the more added in order to obtain a plate-shaped glass is required, so that the plate-shaped glass to achieve a transmittance of 10% in the near-infrared region, in order to increase the enemy intensity of the external light side peak in the absorption spectrum, Cu ^{2 +} at a raw material step Needs to be.

To do this with respect to a result of prediction of the absorption spectrum with respect to Cu ^{2 +} a hexafluorophosphate glass in a case where further addition, is shown in Fig. And based on FIG. 4, the result predicted about the transmittance | permeability of the light in plate glass is shown in FIG. 4 (a) and 5 (a) show prediction results for FIG. 3 (a), and FIGS. 4 (b) and 5 (b) show the results of FIG. The prediction result for b) is shown.

As is shown Figure 4, when the glass product so as to have a (10% transmittance at the wavelength 1200㎚ (about 8300K)) constant near-infrared light absorbing ability is further added the (broken line → thick solid line) Cu ^{+ 2,} the infrared light side Not only does the intensity of the peak increase (double dashed line → thin solid line), but the intensity of the visible light peak further increases (single dashed line → solid line). At this time, FIG. 3 (a) and as O ^{2 -} / P ^{5 +} ratio is high, the visible light side peak and the viscosity (e.g. with a wavelength of about 830㎚ (about 12000K) close to) the original was high strength, the Cu ^{2 +} By further adding, the absorption on the visible light side becomes very strong. As a result, as shown to Fig.5 (a), it will have excessive absorption ability in a visible light region (for example, wavelength 500nm), and the transmittance | permeability of the fluorophosphate glass in a visible light region will fall.

In contrast, O ^{2 -} / P ⁵⁺ If the ratio is lower, the transmittance at the time the work, Cu ^{+ 2} the intensity of the visible light side peak is low and the original as shown in (b) of Figure 3 was added further, 1200㎚ wavelength (about 8300K) 10 Even if it is%, absorption on the visible light side is not so strong. As a result, as shown in FIG.5 (b), the transmittance | permeability of fluorophosphate glass has a moderate absorption ability in a visible light region, and the transmittance | permeability of the fluorophosphate glass in a visible light region can maintain a high value.

From the above results, the knowledge that the O ^{2 −} / P ^{5 +} ratio finally affects whether visible light is absorbed when the fluorinated phosphate glass capable of absorbing near infrared light is produced (that is, [Knowledge 1]) , Obtained by the effort of the present inventors.

The present inventor not only obtained this [Knowledge 1], but also earned the above-mentioned [Knowledge 2] as a result of earnestly researching based on this [Knowledge 1]. [Knowledge 2] will be described in detail below.

FIG. 6 is a graph showing the relationship between the raw material O / P ratio at the raw material time point in the fluorinated phosphate glass and the transmittance after the fluorinated phosphate glass is produced. In that case, a series of each plot is shown for every raw material F ratio. In addition, melting temperature is 1000 degreeC.

In addition, although the glass thickness is changed so that the intensity | strength of a visible light side peak may become equal in the plot for every raw material F ratio, FIG. 6, "raw material F ratio", "glass thickness", and "raw material O / P ratio" other than (e. g. other compositions, including the Cu ^{+ 2)} are in the same manner.

In Fig. 6, when the raw material F ratios are 0.04 and 0.08, as shown in [Knowledge 1], when the intensity of the visible light peak is constant in each plot, as the raw material O / P ratio increases, O ^{2 −} / P ^{+ 5} ratio increased due to the intensity of the infrared light side peak decrease as it can be seen that haebeo Lee (i.e. transmittance increases). Specifically, since the intensity of the visible peak is constant in each plot, when the raw material O / P ratio is high (that is, when the O ² / P ⁵⁺ ratio is high), the intensity of the visible peak is originally high. to, and does not add only a small amount of Cu ^{+ 2.} As a result, the intensity of the infrared side peak decreases and the transmittance increases.

On the other hand, when the raw material F ratio is 0.11 and 0.15, even if it mix | blends and mixes raw material O / P ratio in a raw material step, it turns out that the difference in transmittance | permeability is in the state which does not become much when it is finally made into glass. That is, based on [Knowledge 1], even if the raw material O / P ratio is changed and blended in the raw material step, each plot (for example, when the raw material F ratio is 0.15, the raw material O / P ratio is 3.05). and among the point of 3.09), and finally is in is small (that is, substantially the same O ² difference in the composition when the glass ^- it can be seen that it is a glass having a / P ratio ^{+ 5).}

In order to pursue this cause, the inventors conducted further experiments. Specifically, when the raw material F ratio in FIG. 6 was set to 0.15, experiments were also conducted for the different melting temperatures (900 ° C and 1000 ° C, respectively). The resulting graph is shown in FIG.

7, it turns out that the said tendency becomes remarkable by raising melting temperature. In other words, by increasing the melting temperature to promote the reaction, even when the raw material O / P ratio is changed and blended in the raw material step, when the product glass is finally used, the transmittance becomes the same, and further, almost constant O ^{2 −} / P ^{5 +} It can be seen that it is raining.

Based on FIG. 6 and FIG. 7, the present inventor examined the cause of this phenomenon. As a result, this phenomenon was estimated that POF ₃ volatilizes and a glass composition changes from a raw material stage. Therefore, the ratio is higher raw material F, and promotes the volatilization of the POF _3, and finally a constant O ^{2 -} speculated / P ^{5 +} ratio (about 3.3) that the closer. Similarly, by raising the melting temperature, the volatilization of POF ₃ was promoted, and finally, it was assumed that the ratio was close to a constant O ^{2 −} / P ^{5 +} ratio. That is, the O ^{2 −} / P ^{5 +} ratio is affected by the raw material F ratio (or melting temperature). In other words, the O ^{2 −} / P ^{5 +} ratio in the product glass can be controlled by the raw material F ratio (or melting temperature).

The above idea was unified and the above [Knowledge 2] was obtained.

[Knowledge 3] can be obtained by examining this [Knowledge 2] at a completely different time. That is, in [Knowledge 2], finally approaching a constant O ^{2 −} / P ^{5 +} ratio (about 3.3) means that the fluorophosphate glass finally has a composition of O ^{2 −} / P ^{5 +} ratio = 3.5 (pyrophosphate). by variations in the manufacturing conditions, it is in / P ^{5 +} ratio of 3.3 of the composition (tripolyphosphate structure) is a stable structure as an intermediate step, such as optical ^{properties-structure),} even if this, O ² in hexafluorophosphate glass You can imagine it hard to change. From this imagination, [Knowledge 3] can be obtained.

Based on the [Knowledge 1]-[Knowledge 3] obtained in this way, although this inventor absorbed near-infrared light by containing Cu2 ⁺ , in order to obtain the fluorophosphate glass like not absorbing visible light substantially, Was reviewed.

Whether the Cu ^{2 +} we can properly contain is, O ^{2 -} / P ^{5 +} affected by rain. The O ^{2 -} / P ^{5 +} ratio is influenced by the raw material F rain or melting temperature. This influence is due to the volatilization of the substance which existed at the raw material stage. If so, the material F ratio, set low enough to be the first place volatilization does not occur, and when preventing the O and P separated from the raw material, it is possible to eliminate the effect, possible O In an appropriate amount of Cu ^{2 + 2 -} It was thought that the / P ^{5 +} ratio could be assured to have the fluorophosphate glass after production. Moreover, since a volatilization does not generate | occur | produce substantially by doing in this way, raw material F ratio becomes substantially the same as F <^{-> in} glass after manufacture. Furthermore, the raw material O / P ratio is also substantially the same as the O ^{2 −} / P ^{5 +} ratio in the glass after manufacture.

In addition, F ^- inde for non-, O ^{2 -} / P high and the ^{5 +} ratio than in the prior art, a sufficient weather resistance while, F ^- lower the ratio of all-Patent Document 2 to 6 concept is the idea contrary to the In common sense, a person skilled in the art to be. As described above, by increasing the O ^{2 −} / P ^{5 +} ratio, the bond between O and P in the POP chain is cleaved by F, which may lower the glass strength and deteriorate weather resistance. In addition, other metals in the glass and the pyrophosphoric acid structure may bind to each other to form crystals. Also to prevent them, F in the glass ^- because it is common sense to increase the ratio.

However, the present inventors have attempted to lower the raw material F ratio and further the F ⁻ ratio in the glass, without being bound by such common sense. Further, F ^- and involves lowering the ratio, O ^{2 -} / the P ^{5 +} ratio, while higher than the prior art with the appropriate value, so that in addition an appropriate amount of Cu ^{2 +,} F ^- ratio, and the O ^{2 -} / P ^{5 +} ratio This inventor examined. As a specific numerical example, based on [Knowledge 3], the target is set so that the O ^{2 −} / P ^{5 +} ratio becomes a numerical value near 3.3 (that is, a numerical value within a predetermined width centered on 3.3 or a close value thereof), Raw material F ratio Furthermore, the method of setting F <^-> ratio much smaller than before is examined.

In addition, the present inventor is also intensively examining the melting temperature, the raw material F ratio and F ⁻ ratio thereof, and the degree of volatilization thereof.

In addition, Patent Document 12 describes that the O ^{2 −} / P ^{5 +} ratio is 3.4 or more and the F ⁻ ratio is 0.05 or more. However, Patent Document 12 has, no disclosure is also suggested for the above-mentioned [knowledge 1] to [knowledge 3, the light absorbing ability in the visible light region when further addition of Cu ^{2 +,} and further the light from the near-infrared region There is no description which makes absorption ability a subject. As a proof, in the Example of patent document 12, the reduction of the transmittance | permeability ((lambda) 50 = 615nm) in a near-infrared light region (1200nm) stays at about 23%.

The form of this invention made based on the above knowledge and examination result is as follows.

The first aspect of the present invention,

In the near-infrared hexafluorophosphate glass that absorbs ultraviolet light by containing a Cu ^{+ 2,}

O ² to P ^{5 +} content in the hexafluorophosphate glass ^- the molar ratio (O ^2- / P ⁵⁺⁾ of the content is not less than 3.4 less than 3.2,

The molar ratio of the content (F ^{- -} / (O ^2- + F ^-)) for the total content of F ^- O ² in the glass hexafluorophosphate ^- and F is a fluoride phosphate glass, characterized in that not more than 0.05 or 0.25.

However, the said fluorinated phosphate glass does not contain B3 ⁺ , Pb and its ion and compound, and Tl and its ion and its compound.

The 2nd form of this invention is a form as described in a 1st form,

The ratio of the rare earth ion content to the content of all the cationic components in the fluorinated phosphate glass is characterized by being 0.5 cation% or more and 2.0 cation% or less.

The 3rd form of this invention is a form as described in a 1st or 2nd form,

In the spectral transmittance with respect to fluorophosphate glass, the transmittance | permeability of wavelength 1200nm is less than 15% in the thickness which shows the transmittance | permeability 50% in wavelength 615nm, It is characterized by the above-mentioned.

The 4th aspect of this invention used the fluorinated phosphate glass in any one of 1st-3rd aspect, It is a near-infrared light absorption filter characterized by the above-mentioned.

According to a fifth aspect of the present invention,

In a combination of a glass material, a hexafluorophosphate glass is produced by melting the glass raw materials, the manufacturing method of hexafluorophosphate glass to near infrared absorbing external light by containing a Cu ^{+ 2,}

The composition of the glass hexafluorophosphate, O ² on the P ^{+ 5} content of the phosphoric acid in the fluoride glass ^- the molar ratio of the content (O ^2- / P ⁵⁺⁾ is at least 3.4 less than 3.2, and O in the glass hexafluorophosphate ^2- and F ^- content ratio of ^- F for the total content of ^{(F - / (O 2 -} + F -)) is set to be 0.05 or more 0.25 or less, based on the composition is set by combining a glass material, It is a manufacturing method of fluoride phosphate glass characterized by producing glass.

However, the said fluorinated phosphate glass does not contain B3 ⁺ , Pb and its ion and compound, and Tl and its ion and its compound.

The sixth aspect of the present invention is the aspect described in the fifth aspect,

The glass raw material contains at least fluorine, oxygen, phosphorus,

The glass raw materials are combined so that the molar ratio of oxygen to phosphorus contained in the glass raw material is not less than 3.2 and less than 3.4, and the molar ratio of content of fluorine to the total content of oxygen and fluorine contained in the glass raw material is Glass is produced by combining the said glass raw material so that it may become 0.05 or more and 0.25 or less.

7th aspect of this invention is a aspect as described in a 5th or 6th aspect,

The ratio of the rare earth ion content to the content of all the cationic components in the fluorinated phosphate glass is 0.5 cation% or more and 2.0 cation% or less, and the melting temperature is 1000 ° C. or less.

The 8th aspect of this invention is a form as described in any one of 5th-7th aspect,

In the spectral transmittance with respect to fluorophosphate glass, the transmittance of wavelength 1200nm is less than 15% in the thickness which shows the transmittance | permeability 50% in wavelength 615nm, It is characterized by the above-mentioned.

According to the invention, the absorption of but absorbs the near infrared light visible light is O ² is set to be added to the amount of Cu ^{2 +} of the degree of suppressing ^- having a / P, weather resistance has even after producing a ^{5 +} a non-hexafluorophosphate glass And a manufacturing method thereof and a near infrared light absorption filter.

1, in the patent documents 2 to 6, the O ^{2 −} / P ^{5 +} ratio was selected to be less than 3.5 while the ratio exceeded 3.0, and the O ^{2 −} / P ^{5 +} ratio and the F ⁻ ratio were listed. It is a figure which shows that.
Fig. 2 is a graph when a transmittance spectrum of 500 nm to 1500 nm was measured for a product glass having O ^{2 −} / P ^{5 +} ratio = 3.5 (Comparative Example 1), and the abscissa indicates the wave number (K, ie cm ^−1). ), The vertical axis is converted into absorbance (arbitrary unit).
Of Figure 3 (a) is a O ^{2 -} / P ^{5 +} ratio is high (i.e., O ^{2 -} / P ^{5 +} ratio of 3.5 (Comparative Example 1)) to remove the infrared light side peak and the visible light side peak in the graph of It's a graph. FIG. 3 (b) shows the separation of the infrared and visible peaks in the graph when the O ^{2 −} / P ^{5 +} ratio is low (that is, the O ^{2 −} / P ^{5 +} ratio = 3.18 (Reference Example 1)). It's a graph.
FIG. 4A is a graph obtained by multiplying the absorption spectrum by a coefficient such that the transmittance of the product glass at a wavelength of 1200 nm (about 8300 K) is 10% with respect to the graph of FIG. 3A. The spectrum is 1.22 times and corresponds to 1.22 times the thickness. FIG. 4B is a graph obtained by multiplying the absorption spectrum by a coefficient such that the transmittance of the product glass at a wavelength of 1200 nm (about 8300 K) is 10% with respect to the graph of FIG. 3B. The spectrum is 1.4 times and corresponds to 1.4 times the thickness.
FIG. 5A is a graph when the graph of FIG. 4A is converted into the horizontal axis: wavelength (nm) and the vertical axis: transmittance (%). FIG. 5B is a graph when the graph of FIG. 4B is converted into the horizontal axis: wavelength (nm) and the vertical axis: transmittance (%).
Fig. 6 shows the transmittance at the wavelength of 1200 nm when the thickness of the product glass is adjusted such that the transmittance at the wavelength of 615 nm is 50%, and the raw material F / r ratio as the horizontal axis. It is a graph plotted every time.
FIG. 7 shows the transmittance at wavelength 1200 nm when the thickness of the product glass is adjusted so that the transmittance at wavelength 615 nm is 50%, the raw material O / P ratio is the horizontal axis, Plotted graph.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in the following order.

1. Manufacturing Method of Fluorinated Phosphate Glass

2. Fluorinated Phosphate Glass

3. Effect by embodiment

4. Other

<1. Manufacturing Method of Fluorinated Phosphate Glass>

The fluorinated phosphate glass in this embodiment combines a glass raw material, melts the said glass raw material, and is produced. And a hexafluorophosphate glass, has the capability of absorbing the near-infrared to infrared light by containing a Cu ^{+ 2.}

In the production of this fluorinated phosphate glass, the molar ratio (O ^{2 −} / P ^{5 +} ) of the O ^{2 −} content to the P ^{5 +} content in the fluorinated phosphate glass is determined by the composition of the fluorinated phosphate glass in the product glass step. That is, the O ^{2 −} / P ^{5 +} ratio is not less than 3.2 and less than 3.4, and the molar ratio (F ⁻ / (O ^{2 −)} of the F ⁻ content to the total content of O ^{2 −} and F ⁻ in the fluorinated phosphate glass. + F ⁻ )) (ie, F ⁻ ratio) are set to be 0.05 or more and 0.25 or less, and the glass raw materials are combined based on the set composition.

As described above, the [knowledge 1] to [knowledge 3], it is possible in this embodiment, which does not generate the volatiles (POF ₃₎ substantially free. By substantially not generating volatiles, the main fluctuation factor of the composition in the glass disappears from the step of combining the glass raw materials to the step of becoming a product glass through melting. Therefore, in order to obtain the product glass which has the said composition, you may use the glass raw material which has the same composition.

Therefore, the said glass raw material contains at least fluorine, oxygen, and phosphorus, and the composition in a product glass step may satisfy | fill the said conditions, and may satisfy | fill the following conditions further. That is, the glass raw materials are combined so that the molar ratio (O / P) (i.e. raw material O / P ratio) of the content of oxygen to the content of phosphorus contained in the glass raw material is not less than 3.2 but less than 3.4, and in the glass raw material You may combine the said glass raw material so that molar ratio (F / (O + F)) (namely, raw material F ratio) of content F of fluorine with respect to the total content of oxygen and fluorine contained may be 0.05 or more and 0.25 or less.

Here, O ^{2 -} / P ^{5 +} If the ratio and the raw material O / P ratio is more than 3.2, because it is able to properly cut a POP chain in advance, it becomes possible to sufficiently suppress the generation volatilization of water at the time of melting the glass raw materials do. Moreover, since cutting | disconnection of POP chain by a water molecule can be suppressed, sufficient weather resistance can also be provided with respect to product glass.

In addition, 3.2 of levels, O ² obtained from the knowledge 3] ^- / P ^{5 +} ratio of 3.3 of at the point value in the vicinity of the value, not only does not generate volatiles in a substantially relatively stable tripolyphosphate structure as the structure In addition, the stability as a product glass also increases.

Here, O ^{2 -} / P ^{5 +} ratio, and as described in the raw material O / P if the ratio is less than 3.4 [knowledge 1], so as to have a desired near-infrared light absorbing ability even if there was and the product glass containing Cu ^{2 +,} the visible light absorption capability is excessive Can be suppressed. At that time, it becomes possible to suppress the color development when Cu ²⁺ is added.

On the other hand, F ^- if the ratio and the raw material F ratio is 0.05 or more, O ^{2 -} / P ^{5 +} even if that ratio, and a value of the raw material O / P ratio of for example 3.4 approximately, sufficient amounts (between or tripolyphosphate structure) between pyrophosphate structure F can be interposed, and the structure from which the POP chain was cut | bonded can be tied together. As a result, crystallization resulting from cutting | disconnecting POP chain can fully be suppressed, and also sufficient weather resistance can be provided with respect to a product glass.

In addition, when F ^- ratio and the raw material F ratio are 0.25 or less, it demonstrated also in [Knowledge 2], It becomes possible not to generate | occur | produce a volatile substantially at the low temperature which can melt a glass raw material at least. In addition, since the relative amount of oxygen relative to fluorine is not made too high, as a result, the O ^{2 −} / P ^{5 +} ratio and the raw material O / P ratio can be kept appropriately high, thereby further suppressing substantial generation of volatiles. can do. As a result, from the step of combining the glass raw materials to the step of forming the product glass through melting, the main variation factor of the composition in the glass is eliminated, and the O ^{2 −} / in the product glass is obtained so as to have a desired near infrared light absorption ability. It is possible to control the P ^{5 +} ratio.

In short, not excessively absorb visible light, even if appropriately ^{Cu 2 + O 2 - / P} 5+ ratio ([knowledge 1]) is, O ² which is relatively stable tripolyphosphate structure ^- / P ratio = ^{5 +} Attention is drawn to values close to 3.3 (Knowledge 3). Then, the product glass has the value ^- to have a (O ² / P ⁵⁺ ratio), a raw material F ratio ^- the (consequently the F ratio) substantially eliminating the generation of water by volatilization in the above range, the variation factor of the main composition Resolve ([Knowledge 2]).

As described above, due to the presence of the [knowledge 1] to [knowledge ^{3], O 2 - / P} 5 + ratio and the raw material O / P ratio at the same time as or more and less than 3.2 3.4 F ^- 0.05 the ratio and the raw material F ratio It is possible to derive the configuration of not less than 0.25. That is, although each numerical range itself is significant, in this embodiment, the true value is exhibited only when both numerical ranges are combined. That is, by being a glass composition acceptable at the same time in the value range of the two, "absorb infrared light and" while "inhibiting the color development, and" the addition of approximately an amount of Cu ^{2 +} of the "absorption of visible light is to inhibit" in hexafluorophosphate glass It may, "so set O ^{2 -} may enable control from / P ^{5 +} non-glass material, and step" addition "and a weather resistance" is obtained a hexafluorophosphate glass to exert more effects.

In addition, <2. Which is mentioned later. Fluorinated phosphate glass> is explained in full detail, but the ratio of the rare earth ion content with respect to content of all the cationic components in the said fluorinated phosphate glass may be 0.5 cation% or more and 2.0 cation% or less. By doing in this way, meltable temperature can be reduced and it becomes possible to cause backfire of a manufacturing process. When the rare earth ion content is in the above range, the melting temperature can be set to 1000 ° C. or lower, and therefore it is preferable to melt the glass raw material at the temperature.

Hereinafter, unless otherwise indicated, content of cationic component and total content are represented by the cation%, content of anionic component is represented by anion%, or is simply expressed by%.

In addition, in the above, although the composition which glass product has and a composition glass after manufacture was demonstrated, the specific process, such as melting in the manufacturing method of fluorophosphate glass, is conventionally used, such as a cast, a pipe outflow, a roll, a press, etc. You can use As a specific example of this process, <4. Listed in the item of Other>.

However, when using the above-mentioned conventional method, it is desirable to produce glass without substantially varying the molar ratio by combining the glass raw materials based on the set composition, and trapping the exhaust gas in a closed system to melt the glass raw materials. desirable. In the present embodiment, it is possible to substantially not generate volatiles in the first place. However, in order to eliminate possible variation in composition, the glass raw material is melted and cooled in an airtight container in which exhaust gas is also trapped. It is preferable to produce glass.

<2. Fluorinated Phosphate Glass>

As described above, the fluorinated phosphate glass produced by the above method has a composition substantially similar to that of the glass raw material step. As a result, the hexafluorophosphate glass in this embodiment, while having the ability to absorb ultraviolet light near infrared by containing Cu ^{2 +,} O ² to P ^{5 +} content in the hexafluorophosphate ^glass-molar ratio of the content (O ^2- / P ⁵⁺⁾ is at least 3.2 less than 3.4, O ² in the hexafluorophosphate ^glass-molar ratio of the content ^{(F - - / (O 2-} + F -) F for the total content of the ^- and F) is 0.05 or more and 0.25 or less.

Moreover, it is especially preferable that the fluorophosphate glass in this embodiment has a transmittance of wavelength 1200nm less than 15% in the thickness which shows the transmittance | permeability in wavelength 615nm 50% in the spectral transmittance | permeability with respect to the fluorophosphate glass. Do. In addition, the numerical value of less than 15% is derived from the transmittance | permeability becoming less than 15% when the raw material O / P ratio is 3.4 in the plot of the raw material F ratio in FIG.

When the composition of a glass raw material and a product glass satisfy | fills the conditions mentioned above, the fluoride phosphate glass which has sufficient absorption ability in a near-infrared light region, suppresses absorption ability in a visible light region, and transmits visible light is obtained. This is only to compare the transmittance (Table 1) of the fluorophosphate glass of the present Example mentioned later and the transmittance | permeability of Table 1 of patent document 12, and this Example is reducing the transmittance | permeability to about half in the near-infrared region. (I.e. it can absorb near-infrared light). It that has produced this result, that is, it is possible to obtain a fluoride phosphate glass that satisfies the above conditions, and further absorption of yet absorbed near infrared light visible light is able to be added to the amount of Cu ^{2 +} of the degree of suppressing Because there is.

Moreover, it is preferable to make the ratio of the rare earth ion content with respect to content of all the cationic components in fluorophosphate glass into 0.5 cation% or more and 2.0 cation% or less.

If content of the rare earth ion contained as a cation component is the said range, the rise of the melting temperature of a glass raw material, liquidus temperature, the outflow temperature of a molten glass, and shaping | molding temperature can be suppressed suitably. In the present embodiment, the generation of volatiles is surely substantially achieved by setting the O ^{2 −} / P ^{5 +} ratio and the raw material O / P ratio to 3.2 or more and less than 3.4 (also, the F ⁻ ratio and the raw material F ratio are 0.05 or more and 0.25 or less). While suppressing, the weather resistance of the product glass is secured. However, suppressing the rise of the dissolution temperature, the liquidus temperature, and the molding temperature in addition to this can further ensure the weather resistance of the product glass while substantially suppressing the generation of volatiles.

Moreover, in glass with high liquidus temperature, when the outflow temperature and shaping | molding temperature are going to fall, the viscosity of the glass at the time of outflow and shaping | molding becomes high, and it becomes difficult to isolate | separate molten glass mass or molten glass droplet from molten glass, or it is difficult to shape | mold It is also built.

On the other hand, since the refractive index can be increased without coloring the glass and without drastically lowering the thermal stability, any one or more of Y, La, Gd, and Yb may be selected when introducing rare earth ions. It is preferable to introduce.

For this reason, it is preferable to make the total content of the said rare earth ion into 0.5 cation% or more and 2.0 cation% or less. Additionally, Y ^{+ 3,} La ^{+ 3,} Gd ^{+ 3,} and it is preferable that the total content is less than 2.0%, at least 0.5 cation% cationic including Yb ^{3 +.} Among them, Y is preferably in the strengths of the effect of increasing the refractive index while maintaining the thermal stability, the total content including the Y ^{+ 3} in a range from 0.5% to 2.0 cation% cationic.

As where for example a guide only, the above conditions after satisfying ^{(O 2 - - / P 5} + ratio and the raw material O / P ratio, and F ratio and the value range of the material F ratio), the composition of the fluorinated phosphate glass of the embodiment The following are mentioned as what was shown by the cation% display.

P ^{5 +} 3-50%,

Al ^{3 +} 5 to 40%,

Li ⁺ 0-30%,

Na ⁺ 0-20%,

K ⁺ 0-20%,

Mg ^{2 +} 0 to 10%,

Ca ^{2 +} 0 to 30%,

Sr ^{2 +} 0-30%,

Ba ^{2 +} 0 to 40%,

However, Mg ^{+ 2,} Ca ^{+ 2,} Sr ^{+ 2,} and the total amount of Ba ^{2 +} of at least 10%,

Zn ^{2 +} 0-20%,

In ^{2 +} 0-20%,

Y ^{3 +} 0-10%,

La ^{3 +} 0 to 10%,

Gd ^{3 +} 0-10%,

Yb ^{3 +} 0 to 10%,

Cu ^{+ 2} 0.5 to 13%

In addition to containing an anion% display,

F ^- 20 to 95%,

O ^{2 -} 5% to 80%

The fluorinated phosphate glass containing these is mentioned.

Hereinafter, each said composition is demonstrated.

P ^{5 +} is an important ingredient acting as a network-forming component in the glass. In addition, a characteristic portion of O ² in this embodiment ^- is one of the factors that determine the / P ratio ^{+ 5.} Basically, the above-mentioned O ^{2 -} but if the amount of P ^{+ 5} in the range of / P ratio ^{+ 5,} such a numerical value as one example, not less than 3% hexafluorophosphate this glass is stable. Moreover, if it is 50% or less, the required low dispersibility can be obtained. Therefore, the content of P ^{+ 5} is preferably in a range of from 3 to 50%.

Al ^{3 +} is an important ingredient for enhancing the reliability in fluoride phosphate glass, not less than 5% hexafluorophosphate this glass is stable. Moreover, if it is 40% or less, the total amount of other components can be ensured and it is stabilized similarly. Therefore, the content of Al ^{+ 3} is preferably in a range of 5 to 40%.

Alkali metals, such as Li ⁺ , Na ⁺ , K ⁺ , are components that can lower the viscosity and glass transition temperature of the glass and facilitate the manufacture of the glass. Therefore, the amount of Li ⁺ is preferably 0 to 30%, the amount of Na ⁺ to 0 to 20%, ^and the amount of K ⁺ to 0 to 20%. Among the alkali metals, Li ⁺ also has a large effect of increasing stability, so it is more preferable to introduce Li ⁺ at least 0.5%, more preferably at least 1%, particularly preferably at least 2%.

^{Mg 2 +, Ca 2 +,} Sr 2 +, an alkaline earth metal such as Ba ^{2 +} will increase the stability of the glass, a component for increasing the refractive index, the higher the effect on the stability by the total amount to 10% or more. In addition, Mg ^{+ 2,} Ca ^{+ 2} is a useful component for resistance to devitrification of the glass, improves the durability and processability. Sr ^{2 +,} Ba ^{2 +} is a useful component for improving the resistance to devitrification of the glass, the melting property.

However, since a particular alkaline earth metal component to break the balance, and so increases, the other components, be desirable to uniformly introduced, and introducing the Mg ^{2 +,} Ca ^{2 +,} Sr ^{2 +,} Ba ^{2 +} of the at least two or more of desirable. Preferred content of each component, Mg ^{+ 2} from 0 to 10%, Ca ^{+ 2} is from 0 to 30%, Sr ^{2 +} is 0 to 30%, Ba ^{+ 2} is 0-40%.

Zn ^{2 +,} In ^{3 +} has a characteristic that can be easily introduced into the glass like alkaline earth metals, and can be expected to improve the stability effect that by introducing the Zn ^{2 +} or In ^{3 +} is to the component, the excess Introduction is undesirable. Therefore, the introduced amount of Zn ^{2 + 3} and In ⁺ is particularly preferably at 0 to not introduce desirable, and that of 20%.

^{Y 3 +, La 3 +,} Gd 3 +, inde rare earth element component to increase the refractive index while maintaining the low-dispersion glass such as Yb ^{3 +,} excessive introduction of turns to also decreases stability of the glass by raising the melting temperature. Therefore, it is preferable to make the quantity of each said component 0 to 10%, respectively.

Further, in this embodiment, it is added to Cu ^{2 +} in the glass raw material. By adding Cu ²⁺ , the near-infrared light absorption characteristic can be imparted to the product glass. In the present embodiment, to be sufficiently added to the amount of Cu ^{2 +} of the degree capable of absorbing light in the near-infrared region, the addition of an amount of Cu ^{2 +,} such as the light absorption in the visible region is not excessively absorbed Done. As described above, this addition amount is determined by the O ^{2 −} / P ^{5 +} ratio and the raw material O / P, and the F ⁻ ratio and the raw material F ratio. However, it is preferred to instance an example of the figures, the addition of 0.5 to 13% of Cu ^{2 +} a oehal added.

Further, Cu ^{+ 2-containing} glass is suitable as a color correction filter material of the semiconductor image pickup device such as CCD or CMOS. The addition amount of Cu ^{2 +} is, in consideration of the thickness of the filter, it is properly assuming within this range.

Next, an anion component and an anion additive are demonstrated. In the fluorinated phosphate glass in the present embodiment, F ⁻ and O ^{2 −} are the main anionic components. Basically, the above-F ^- in that the good is, instance the figures as an example, achieve the desired optical characteristics with excellent weather resistance, F ^{- -} amount of F in the range of ^non-and O ² of 20 to 95%, O is preferably introduced into a ^2-5 to 80%.

In addition, by introducing a small amount of Cl ⁻ , Br ⁻ , I ⁻ , the fluorinated phosphate glass becomes difficult to wet with platinum products such as platinum containers and platinum nozzles used during the production of the glass or at the time of outflow. Therefore, it becomes possible to easily manufacture glass. However, Cl ^-, Br ^-, I ^- Introduction of excess of are, as they result in the occurrence of the refractive index variation with the platinum foreign substance by the components volatile, the introduced amount is in preferably in a total from 0 to 3%, and 0.1 to 3% It is more preferable to do.

Further, in order to increase the quality of the hexafluorophosphate glass in the present ^{embodiment, F -, O 2 -,} Cl -, Br - and I ^- preferred that the combined amount to more than 98% of, and to more than 99% It is more preferable, and it is still more preferable to set it as 100%.

In addition, in this embodiment, ^{B3 +} is not contained. Although it is a component which improves the durability of glass originally, when it melt | dissolves a glass raw material for a long time, it tends to volatilize as a fluoride. Therefore, B3 ⁺ is not contained in the fluorophosphate glass in this embodiment.

Similarly to B ³⁺ , there are components in which the fluorinated phosphate glass in the present embodiment is not preferably contained. Specifically, Pb, As, Cd, Cr, U, Th, Tl, and the ions and compounds thereof are preferably not contained in consideration of the load on the environment. In addition, about Pb and Tl at least, it is not made to contain in the fluorinated phosphate glass in this embodiment.

<3. Effect by Embodiment>

According to this embodiment, the following effects are exhibited.

That is, while "absorbs near infrared light, and""inhibiting the color development, and" may be added to the amount of Cu ^{2 +} of about "absorption of visible light is to inhibit" in hexafluorophosphate glass, "O ^2- / P is set so ⁵⁺ ratio can be controlled from a glass raw material stage ", and the fluorinated phosphate glass which exhibits numerous effects of" having weather resistance "is obtained.

As a result, the absorption of visible light but absorb infrared light is set to O ² can be added to the amount of Cu ²⁺ of the degree of suppressing ^- having a having even after producing a ^{5 +} ratio / P, and a weather-resistant glass hexafluorophosphate A manufacturing method can be provided.

In addition, while a constant ratio of the glass content of components other than Cu ^{+ 2,} it is possible to balance the "absorption of near infrared light" and "inhibiting the absorption of visible light" bakkueodo the content of Cu ^{2 +.} Therefore, by adjusting the glass content of the content of components with a constant ratio of other than Cu ^{2 +} Cu ²⁺ it is possible to adjust the thickness of the filter. By increasing the content of Cu ^{2 +} can be reduced to the thickness of the filter, you are possible to increase the thickness of the filter by reducing the content of Cu ^{2 +.} That is, according to the present invention, with a constant ratio of the glass content of components other than Cu ^{+ 2,} it is possible to provide the compatible glass material to a thickness of several filters.

Glass component amount ratio of the non-Cu ^{2 +} are the same, the case of producing a filter to a content of Cu ^{2 +} using different free, good-molding glass composition is substantially at the same point, without changing the forming conditions, the processing conditions of the glass, I can process it.

<4. Other>

Hereinafter, the specific example of processes, such as melting, is demonstrated in the manufacturing method of fluorophosphate glass. In that case, the example which manufactures a near-infrared light absorption filter from the glass raw material which satisfy | fills the said requirements as an example is demonstrated below.

Moreover, the case where [Knowledge 1]-[Knowledge 3] is applied other than above embodiment is demonstrated.

(Specific example in the manufacturing method of fluorinated phosphate glass)

First, glass raw materials satisfying the above requirements are weighed and mixed, and then heated and melted in a heat-resistant crucible, for example, a crucible made of platinum or a platinum alloy. In addition, in this embodiment, although volatile matter is not made to generate | occur | produce substantially, it is preferable to put a heat-resistant cover, such as platinum, on a crucible in order to suppose that a small amount of volatile matter generate | occur | produces.

And the glass of a molten state is stirred and clarified, and the homogeneous glass melt which does not contain a bubble flows out from the nozzle for glass outflows made of any one of a platinum agent, a platinum alloy agent, a gold agent, and a gold alloy, and is shape | molded.

Cl which is contained in a glass solution when the glass outlet ^-, Br ^-, I ^- of the glass melt at least one outlet from the nozzle tip, a halogen component or more, the effect of suppressing the wet blasting developed with the outer peripheral surface from the nozzle end nozzle Obtained. As a result, the wet glass melt is deteriorated, introduced into the glass melt flowing out after the deterioration, and the phenomenon of defects such as striae and devitrification can be reduced and prevented.

By the way, in a near-infrared light absorption filter, also in order to comprise the compact imaging system provided with a semiconductor image sensor, it is calculated | required to maintain high transmittance | permeability of visible light, while improving the cut function of near-infrared light. From this point of view, in the glass having a thickness of which the external transmittance at a wavelength of 615 nm is 50%, it is preferable that the light having a wavelength of at least 500 nm is not substantially absorbed. In addition, the term "substantial" as used herein includes the case where no light at this wavelength is absorbed at all, and the case where the absorption is at a practically practical level even if absorbed.

Moreover, it is preferable that the external transmittance in wavelength 400nm is 80% or more. About absorption of near-infrared light, it is preferable that the transmittance | permeability in wavelength 1200nm is less than 15%.

The preparation example of the said near-infrared light absorption filter is as follows.

First, the molten glass clarified and homogenized so that the said glass is obtained is melt | dissolved, it flows out from a pipe, it flows into a mold, and the glass block of a large plate with a thick plate thickness is shape | molded. For example, prepare a mold composed of a flat and horizontal bottom surface, a pair of side walls facing each other in parallel with the bottom surface and a barrier plate blocking one opening located between the pair of side walls, A molten glass homogenized at a constant outflow speed is injected into the mold from a platinum alloy pipe. The injected molten glass is unfolded in the mold and molded into a plate-shaped glass regulated to a constant width by a pair of side walls. The shaped plate glass is continuously drawn out from the opening of the mold. By setting the shaping | molding conditions, such as a shape, a dimension of a mold, and the outflow speed of a molten glass, here, a thick glass block can be shape | molded while being a large plate.

In addition, melting of a glass raw material may be performed in atmosphere of inert gas, such as nitrogen gas, or dry gas, and may be performed in air | atmosphere. According to the present invention, high-quality fluorinated phosphate glass can be produced and supplied without being affected by the glass melting atmosphere.

The molded glass block is transferred to an anneal previously heated near the transition temperature of glass, and is cooled to room temperature. The glass block from which distortion was removed by slow cooling is subjected to slice, grinding, and polishing with high precision, and thus a glass plate having both surfaces optically polished can be obtained. Although this glass plate can also be used as a near-infrared light absorption filter, the said glass plate can be bonded together and a near-infrared light absorption filter can also be made. Both surfaces of the plate-shaped near-infrared light-absorbing glass on which both surfaces are optically polished are bonded to the plate-shaped crystals on which both surfaces are optically polished. Then, one side of the crystal is bonded to a plate-like optical glass, for example BK-7 (borosilicate optical glass), which is transparent to both surfaces and is optically polished by visible light. Although the near-infrared light absorption filter is comprised by such a structure, you may bond together the plate-shaped optical glass (for example, BK-7) which penetrates the visible light on one side of the said plate-shaped optical glass, and both surfaces were optically polished. An optical multilayer film is formed on the surface of the filter as needed.

As mentioned above, although the case where the glass block is processed by the glass plate was demonstrated, it can also grind and polish a glass block, to produce a lens, or to process to another shape.

Since the near-infrared light absorption glass of this embodiment is fluorophosphate glass, and glass transition temperature is low, it does not grind | grind or grind | polish an optical function surface after shaping | molding by precision press molding (mold molding), Optical elements, such as a lens and a diffraction grating, can also be shape | molded. For example, the molding surface of well-known press-molded members, such as SiC and a cemented carbide, is processed to high precision into the shape which inverted the lens surface of an aspherical lens, and an upper mold | type and a lower mold are produced, and these upper and lower molds or as needed are known. Using the same copper mold or the vertical guide member, the glass preform made of the near-infrared light absorbing glass of the present embodiment is heated and precisely press-molded. In this way, the molding surface can be accurately transferred to the glass, and an aspherical lens can be produced. Such aspherical lens is also the near-infrared light absorption filter of this embodiment. The aspherical lens thus obtained may form part or all of an optical system for forming an image of a subject on the light receiving surface of the semiconductor image sensor, and the number of optical components in the imaging device can be reduced and the space can be reduced. It is effective for saving and cost reduction.

It is also possible to obtain a near-infrared light absorbing filter with a diffraction grating by forming an upper mold and a lower mold by precisely forming a diffraction grating in a shape in which the diffraction grating is inverted on the molding surface of the press-molded member, and by precision press molding the glass preform in the same manner as the above method. .

The near-infrared light absorption filter with a diffraction grating functions as an optical low pass filter of light incident on a semiconductor image sensor. Therefore, the near-infrared light absorbing filter and the optical low-pass filter can be made into one element, so that the number of optical components in the imaging device can be reduced, and space saving and cost can be reduced.

In addition, while the molding surface of the press-formed member has a shape in which the lens surface (for example, the lens surface of an aspherical lens) is inverted, the grooves of the diffraction grating are precisely processed in the inverted shape, and in the same manner as in the above method, When press-molding, a near-infrared light absorption filter which has a near infrared light absorption function, an optical low pass filter function, and a lens function can be manufactured.

You may form a well-known release film in the press molding die molding surface as needed. In addition, what is necessary is just to determine suitably the various conditions of precision press molding by the specific specification of the target near-infrared light absorption filter, applying a well-known thing.

By producing a near-infrared light absorption filter by precision press molding, mass production by grinding and polishing is not suitable, such as aspherical lens, optical low pass filter with diffraction grating, aspherical lens with diffraction grating functioning as optical low pass filter. Even devices can be manufactured under high productivity. In addition, you may form an optical multilayer film, such as an anti-reflective film, on the surface of a near-infrared light absorption filter as needed.

According to the near-infrared light absorption filter of this embodiment, since the transmittance | permeability of visible light is high and absorption of near-infrared light is large, the color sensitivity correction of a semiconductor imaging element can be performed favorably. Moreover, it can also be set as the optically homogeneous filter.

In addition, the near-infrared light absorption filter of this embodiment can be applied to an imaging device by combining with a semiconductor image sensor. The semiconductor image sensor includes a semiconductor imaging device such as a CCD or a CMOS in a package and covers the light receiving portion with a light transmitting member. The light transmitting member may also serve as a near infrared light absorbing filter, and the light transmitting member may be separate from the near infrared light absorbing filter.

In addition, the imaging device of the present embodiment may include an optical element such as a lens or a prism for forming an image of a subject on the light receiving surface of the semiconductor image sensor.

In addition, according to the imaging device described above, since a near-infrared light absorption filter having excellent optical homogeneity, a high transmittance in the visible region, and a large absorption of near-infrared light is mounted, color sensitivity correction is satisfactorily achieved, resulting in an image having excellent image quality. It is possible to provide an imaging device capable of obtaining.

In addition, if it is this embodiment, it can of course also manufacture optical elements (lens etc.) other than a near-infrared light absorption filter. In addition, it is possible to apply to various products made of glass, and various modifications are possible.

(Examples of [Knowledge 1] to [Knowledge 3])

In the present embodiment it has been described with respect to near infrared hexafluorophosphate glass that absorbs ultraviolet light by containing a Cu ^{+ 2.} However, even when the near infrared light-absorbing component other than Cu ^{2 +} (e.g. Al or the already listed above, In, Sn, etc. compounds, such as W or their oxides) or simultaneously added, instead of Cu ^{2 +,} the present invention It may be applicable. That is, the addition of any near-infrared absorbing component, [knowledge 1 may be divided into a light absorbing peak in two steps, the light absorption peak of O ^{2 -} if it is affected by the / P ^{5 +} ratio, the above-described The problem is likely to occur. In addition, [knowledge 2] or [knowledge 3] O ^{2 -} / P ^{5 +} ratio and F ^- In the related information to the non-point, and thus is likely to apply when the addition of ingredients other than the Cu ^{2 +} . About the form which reflected it, it adds to the end of specification.

Moreover, there is also the possibility that the above effects can be exhibited even in the O ^{2 −} / P ^{5 +} ratio, the raw material O / P ratio, and the F ⁻ ratio and the raw material F ratio slightly deviated from the numerical range described in the present embodiment. The form which reflected it is also added at the end of the specification.

[Example]

Next, an Example is shown and this invention is demonstrated concretely. Of course, the present invention is not limited to the following examples.

<Examples 1 to 44>

In order to obtain each glass composition of Examples 1-44 shown in Table 1, raw materials, such as phosphate, such as zinc diphosphate, and fluoride, such as sodium fluoride, were combined, and it puts into a platinum crucible, and Examples 1-11, 16 To 41 are melt temperatures of 1000 ° C., Example 12 is a melt temperature of 900 ° C., and Examples 42 to 44 are heated, dissolved, clarified, and homogenized over 2 to 3 hours with stirring, homogeneous. After obtaining one glass melt, glass melt, ie, molten glass, was poured into the mold, and 44 kinds of fluorinated phosphate glasses corresponding to Examples 1 to 44 were obtained. In addition, in the said process, glass manufacture did not become difficult by generation | occurrence | production of a large amount of volatile components. In addition, precipitation of crystal | crystallization, a residual bubble, a foreign material, and the aspirate were not recognized inside the obtained glass.

<Comparative Examples 1 to 3>

In the embodiment 1, whereas to 44, Comparative Examples 1 and 2, the raw material O / P ratio ^were produced by a comparative example glass above 3.4 (O ² of the glass that is the product / P ratio ^{+ 5).} In addition, in Comparative Example 3, and the Cu ^{2 +} a very small amount of 1.00%. The composition other than that was like Table 1, and it carried out similarly to the Example as a specific manufacturing process.

<Reference Examples 1 to 10>

In addition, other numerical ranges in this embodiment O ^{2 -} while having a / P ratio ^{+ 5,} for example, capable of reducing the transmittance in the near infrared light region, as shown in Reference Example.

Specifically, as Reference Examples 1 to 7, glass in which the raw material O / P ratio (that is, the O ² / P ⁵⁺ ratio in the product glass) was less than 3.2 was produced. Compositions other than that were as shown in Table 1, Reference Examples 1 to 5 set the melting temperature to 1000 ° C, Reference Examples 6 to 7 set the melting temperature to 900 ° C, and the other specific manufacturing processes were the same as in Examples.

In addition, as Reference Examples 8 to 10, glass in which the raw material F ratio (ie, the F ⁻ ratio in the product glass) was less than 0.05 was produced. Other compositions and specific manufacturing processes were as shown in Table 1. The composition other than that was like Table 1, and it carried out similarly to the Example as a specific manufacturing process.

<Transmittance>

About each glass of Examples 1-44, Comparative Examples 1-3, and Reference Examples 1-10, the thickness in which the external transmittance in wavelength 615nm becomes 50%, the external in wavelength 1200nm in this thickness The transmittances (transmittances at wavelengths of 400 nm and 500 nm in some examples) are shown in Table 1.

As shown in Table 1, in the glass of an Example, the transmittance | permeability of a visible region is high, and it is excellent in the cut function of near-infrared light in an Example and a reference example, and is suitable as filter glass for chromatic aberration correction of a semiconductor image sensor.

On the other hand, the glass of the comparative example became 15% or more in all, and compared with the Example and the reference example, the absorption ability with respect to the light of a near-infrared light region was weak. Further, in Comparative Example 3 is glass, since the Cu ^{2 +} a very small amount, can not absorb near-infrared light, in the first place is not roneun "hexafluorophosphate glass that absorbs near-infrared light by containing Cu ^{2 +."} Accordingly, in Comparative Example 3 is glass, O ² within the numerical range of the present embodiment ^- / P ratio ^{+ 5} and F ^- have a non belong to yet and Comparative Examples. Conversely, it is preferable that the content of Cu ^{2 +} excess of 1.00% in the fluorinated phosphate glass of the present embodiment. In addition, in view of the examples 1 to 44, more preferably the content of Cu ^{2 +} 2.50% or more. On the other hand, while maintaining the thermal stability of the glass, it is preferred that the content of Cu ^{2 +} 5% or less.

Hereinafter, other preferable forms are added.

[Appendix 1]

By containing Cu ^{+ 2,} in hexafluorophosphate glass having a peak of light absorption in a near infrared region,

Roasting the peak separation is free in two peaks, Cu ^{+ 2} is no color development, while a wavelength 1200㎚ light is substantially absorbed, the wavelength of light is not substantially absorbed into 500㎚,

O ² in the glass hexafluorophosphate ^- and F ^- the molar ratio of the ^content-F for the total content of ^{(F - / (O 2- +} F -)) range of values is, POF, in the manufacture of the near-infrared light absorbing filter _The fluorinated phosphate glass which makes an upper limit the value of the grade which does not produce ₃ substantially.

Provided that the fluorinated phosphate glass does not contain B ³⁺ , Pb and its ions and compounds, and Tl and its ions and compounds.

[Note 2]

In the near-infrared hexafluorophosphate glass that absorbs ultraviolet light by containing a Cu ^{+ 2,}

O ² to P ^{5 +} content in the hexafluorophosphate glass ^- the molar ratio (O ^2- / P ⁵⁺⁾ of O ^2- / P ⁵⁺ range of the ratio of the content is, POF, in the manufacture of the near-infrared light absorbing filter does not cause a substantial amount of O ² to ^_3-a / P ^{+ 5} ratio to the lower limit of the other hand, Cu ^{+ 2} is no color development, while a wavelength 1200㎚ light is substantially absorbed by, a wavelength of light is substantially 500㎚ to the amount of O ² available in the Cu ^{+ 2} the extent that the ^{absorption-in} / P ratio and the upper limit of ^{5 +,}

O ² in the glass hexafluorophosphate ^- and F ^- the molar ratio of the ^content-F for the total content of ^{(F - / (O 2- +} F -)) range of values is, POF, in the manufacture of the near-infrared light absorbing filter _The fluorinated phosphate glass which makes an upper limit the value of the grade which does not produce ₃ substantially.

Provided that the fluorinated phosphate glass does not contain B ³⁺ , Pb and its ions and compounds, and Tl and its ions and compounds.

[Note 3]

In the near-infrared hexafluorophosphate glass that absorbs ultraviolet light by containing a Cu ^{+ 2,}

And the molar ratio (O ^2- / P ⁵⁺⁾ of the content is 3.40 to less than 3.05, ^- O ² to P ^{5 +} content in the glass hexafluorophosphate

The molar ratio of the content ^{(F - - / (O 2-} + F -)) has a glass hexafluorophosphate, characterized in that less than 0.03 0.19 F for the total content of the ^- O ² in the glass hexafluorophosphate ^- and F.

Provided that the fluorinated phosphate glass does not contain B ³⁺ , Pb and its ions and compounds, and Tl and its ions and compounds.

[Note 4]

The F ^- content of the ratio, P ₂ O ₇ ^{4 -} glass hexafluorophosphate characterized in that the value of a degree that does not cause a crystal due to a lower limit.

[Note 5]

A combination of glass materials and glass, and hexafluorophosphate is produced by melting the glass materials, a method of manufacturing a hexafluorophosphate glass to near infrared absorbing external light by containing a Cu ^{+ 2,}

O ² to P ^{5 +} content in the hexafluorophosphate glass ^- the molar ratio (O ^2- / P ⁵⁺⁾ of O ^2- / P ⁵⁺ range of the ratio of the content is, POF, in the manufacture of the near-infrared light absorbing filter does not cause a substantial amount of O ² to ^_3-a / P ^{+ 5} ratio to the lower limit of the other hand, Cu ^{+ 2} is no color development, while a wavelength 1200㎚ light is substantially absorbed by, a wavelength of light is substantially 500㎚ The ratio of O ^{2 −} / P ^{5 + that} can be added to Cu ^{2 +} in an amount not absorbed is set as an upper limit,

O ² in the glass hexafluorophosphate ^- and F ^- the molar ratio of the ^content-F for the total content of ^{(F - / (O 2- +} F -)) range of values is, POF, in the manufacture of the near-infrared light absorbing filter _The upper limit is set so that the value which does not substantially generate ₃ ,

A glass raw material is combined based on the set said composition, and glass is produced, The manufacturing method of the fluorophosphate glass characterized by the above-mentioned.

However, the said fluorinated phosphate glass does not contain B3 ⁺ , Pb and its ion and compound, and Tl and its ion and its compound.

[Note 6]

A combination of glass materials and glass, and hexafluorophosphate is produced by melting the glass materials, a method of manufacturing a hexafluorophosphate glass to near infrared absorbing external light by containing a Cu ^{+ 2,}

O ² to P ^{5 +} content in the hexafluorophosphate glass ^- the molar ratio (O ^2- / P ⁵⁺⁾ of O ^2- / P ⁵⁺ range of the ratio of the content is, POF, in the manufacture of the near-infrared light absorbing filter the degree that does not cause a substantial ₃ O ^{2 -} / P ^{5 +} a ratio to the lower limit, Cu ^{+ 2} is no color development, while a wavelength 1200㎚ light is substantially absorbed, the light is substantially absorbed by the wavelength 500㎚ Set the ratio of O ^{2 −} / P ^{5 + that} can be added in an amount of Cu ^{2 +} that is not so high as the upper limit,

A method of producing fluorinated phosphate glass, comprising: combining a glass raw material based on the set composition, and trapping the exhaust gas in a closed system to melt the glass raw material to substantially produce the glass without substantially changing the molar ratio.

However, the said fluorinated phosphate glass does not contain B3 ⁺ , Pb and its ion and compound, and Tl and its ion and its compound.

[Note 7]

In the fluoride phosphate glass which absorbs near-infrared light by containing a near-infrared light absorption component,

O ² to P ^{5 +} content in the hexafluorophosphate glass ^- the molar ratio (O ^2- / P ⁵⁺⁾ of O ^2- / P ⁵⁺ range of the ratio of the content it is, POF _3, in the manufacture of the hexafluorophosphate glass While the O ^{2 −} / P ^{5 +} ratio is substantially lower than that of generating substantially no light, the near-infrared light absorbing component does not develop color, while light having a wavelength of 1200 nm is substantially absorbed, while light having a wavelength of 500 nm is substantially to the amount of O ² available in the Cu ^{+ 2} the extent that the ^{absorption-in} / P ratio and the upper limit of ^{5 +,}

O ² in the glass hexafluorophosphate ^- and F ^- the molar ratio of the ^content-F for the total content of ^{(F - / (O 2- +} F -)) range of values is, POF, in the manufacture of the near-infrared light absorbing filter _The fluorinated phosphate glass which makes an upper limit the value of the grade which does not produce ₃ substantially.

However, the said fluorinated phosphate glass does not contain B3 ⁺ , Pb and its ion and compound, and Tl and its ion and its compound.

Claims (8)

By containing Cu ^{2 +} hexafluorophosphate as a glass that absorbs near infrared light,
O ² to P ^{5 +} content in the hexafluorophosphate glass ^- the molar ratio (O ^2- / P ⁵⁺⁾ of the content is not less than 3.4 less than 3.2,
The molar ratio of the ^content-F for the total content of the ^- O ² in the glass hexafluorophosphate ^- and ^{F (F - / (O 2-} + F -)) is not more than 0.05 or 0.25
Characterized in,
The fluorinated phosphate glass contains B ³⁺ , Pb and its ions and compounds, and Tl and its ions and the compounds. The fluorinated phosphate glass according to claim 1, wherein the ratio of the rare earth ion content to the content of all the cationic components in the fluorinated phosphate glass is 0.5 cation% or more and 2.0 cation% or less. The spectral transmittance with respect to fluorophosphate glass WHEREIN: The transmittance | permeability of wavelength 1200nm is less than 15% in the thickness which shows the transmittance | permeability 50% in wavelength 615nm, The fluorophosphate glass of Claim 1 or 2 characterized by the above-mentioned. . The near-infrared light absorption filter using the said fluorophosphate glass in any one of Claims 1-3. Hexafluorophosphate as a glass by combining a glass material, which is produced by melting the glass materials, a method for manufacturing a hexafluorophosphate glass to near infrared absorbing external light by containing a Cu ^{+ 2,}
The composition of the glass hexafluorophosphate, O ² on the P ^{+ 5} content of the phosphoric acid in the fluoride glass ^- the molar ratio of the content (O ^2- / P ⁵⁺⁾ is at least 3.4 less than 3.2, and O in the glass hexafluorophosphate ^2- and F ^- the molar ratio of the ^content-F for the total content of ^{(F - / (O 2- +} F -)) is set to be 0.05 or more and 0.25 or less, based on the above-mentioned composition is set by combining a glass material, Producing glass
Characterized in,
The said fluorinated phosphate glass is a manufacturing method of fluorine phosphate glass which does not contain B3 ⁺ , Pb and its ion and compound, and Tl and its ion and this compound. The method of claim 5, wherein the glass raw material contains at least fluorine, oxygen, phosphorus,
The said glass raw material is combined so that the molar ratio of content of oxygen with respect to content of phosphorus contained in the said glass raw material may be 3.2 or more and less than 3.4, and the molar ratio of content F of fluorine with respect to the total content of oxygen and fluorine contained in the said glass raw material Glass is produced by combining the said glass raw material so that it may become 0.05 or more and 0.25 or less, The manufacturing method of the fluorophosphate glass characterized by the above-mentioned. The ratio of the rare earth ion content to the content of all the cationic components in the fluorinated phosphate glass is 0.5 cation% or more and 2.0 cation% or less, and the melting temperature is 1000 ° C or less. The manufacturing method of fluorophosphate glass made into. The spectral transmittance with respect to fluorophosphate glass WHEREIN: The transmittance | permeability of wavelength 1200nm is less than 15% in the thickness which shows 50% of the transmittance | permeability in wavelength 615nm, The fluorophosphoric acid characterized by the above-mentioned. Method of making glass.

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